US20180023563A1 - Automatic transmission pump apparatus or pump apparatus - Google Patents
Automatic transmission pump apparatus or pump apparatus Download PDFInfo
- Publication number
- US20180023563A1 US20180023563A1 US15/540,868 US201515540868A US2018023563A1 US 20180023563 A1 US20180023563 A1 US 20180023563A1 US 201515540868 A US201515540868 A US 201515540868A US 2018023563 A1 US2018023563 A1 US 2018023563A1
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- United States
- Prior art keywords
- venturi
- pump
- venturi portion
- inner diameter
- hydraulic fluid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2/00—Rotary-piston machines or pumps
- F04C2/30—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
- F04C2/34—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members
- F04C2/344—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
- F04C14/10—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by changing the positions of the inlet or outlet openings with respect to the working chamber
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
- F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
- F04C14/24—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
- F04C14/26—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves using bypass channels
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2/00—Rotary-piston machines or pumps
- F04C2/30—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
- F04C2/34—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members
- F04C2/344—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
- F04C2/3446—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along more than one line or surface
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C14/00—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations
- F04C14/18—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber
- F04C14/22—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber by changing the eccentricity between cooperating members
- F04C14/223—Control of, monitoring of, or safety arrangements for, machines, pumps or pumping installations characterised by varying the volume of the working chamber by changing the eccentricity between cooperating members using a movable cam
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2/00—Rotary-piston machines or pumps
- F04C2/30—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members
- F04C2/34—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members
- F04C2/344—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member
- F04C2/3441—Rotary-piston machines or pumps having the characteristics covered by two or more groups F04C2/02, F04C2/08, F04C2/22, F04C2/24 or having the characteristics covered by one of these groups together with some other type of movement between co-operating members having the movement defined in groups F04C2/08 or F04C2/22 and relative reciprocation between the co-operating members with vanes reciprocating with respect to the inner member the inner and outer member being in contact along one line or continuous surface substantially parallel to the axis of rotation
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2230/00—Manufacture
- F04C2230/20—Manufacture essentially without removing material
- F04C2230/21—Manufacture essentially without removing material by casting
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2240/00—Components
- F04C2240/20—Rotors
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2240/00—Components
- F04C2240/60—Shafts
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
- F04C2270/00—Control; Monitoring or safety arrangements
- F04C2270/21—Pressure difference
- F04C2270/215—Controlled or regulated
Definitions
- the present invention relates to a pump apparatus.
- a pump apparatus including a control valve.
- the control valve controls a flow amount of hydraulic fluid that the pump apparatus supplies to an apparatus.
- a pump apparatus discussed in PTL 1 generates a differential pressure according to the flow amount to be discharged.
- the control vale controls the above-described flow amount by switching a flow passage of the hydraulic fluid based on the above-described differential pressure.
- An object of the present invention is to provide a pump apparatus capable of preventing or reducing deterioration of the efficiency of the pump.
- one embodiment of the present invention includes a venturi portion provided on the way along a discharge passage to generate a differential pressure and having an inner diameter gradually increasing from a small diameter portion toward a downstream side of the discharge passage.
- FIG. 1 illustrates a configuration of a hydraulic system to which a pump apparatus according to a first embodiment is applied.
- FIG. 2 schematically illustrates a configuration of the pump apparatus according to the first embodiment.
- FIG. 3 illustrates a partial cross section acquired by cutting a pump housing according to the first embodiment along a plane perpendicular to a central axis of a diving shaft.
- FIG. 4 illustrates a cross section as viewed from a line A-A illustrated in FIG. 3 .
- FIG. 5 illustrates a venturi forming block according to the first embodiment as viewed from one side in an axial direction.
- FIG. 6 schematically illustrates a discharge passage around a venturi portion according to the first embodiment.
- a lower diagram of FIG. 6 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram.
- FIG. 7 schematically illustrates a discharge passage around an orifice according to a comparative example.
- a lower diagram of FIG. 7 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram.
- FIG. 8 is a graph indicating a relationship between a flow amount and a differential pressure according to the first embodiment.
- a solid line indicates the first embodiment, and an alternate long and short dash line indicates the comparative example.
- FIG. 9 illustrates a relationship between a narrower angle and a pressure loss rate according to the first embodiment.
- FIG. 10 schematically illustrates a discharge passage in which a large diameter portion is provided upstream of the venturi portion according to the first embodiment.
- a lower diagram of FIG. 10 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram.
- FIG. 11 schematically illustrates a discharge passage including a stepped portion (a rear portion) on a downstream side of an inner diameter gradually-increasing portion according to the first embodiment.
- a lower diagram of FIG. 11 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram.
- FIG. 12 illustrates a relationship between L/L 0 , which is a ratio of L to L 0 illustrated in FIG. 11 , and the pressure loss rate.
- FIG. 13 illustrates a cross section acquired by cutting a venturi forming block according to a second embodiment along a plane passing through a central axis of the venturi portion.
- FIG. 14 illustrates a pump housing according to a fourth embodiment as viewed from a direction in which the central axis of the driving shaft extends.
- FIG. 15 illustrates a cross section as viewed from a line B-B illustrated in FIG. 14 .
- FIG. 16 schematically illustrates a configuration of a pump apparatus according to a sixth embodiment.
- FIG. 17 illustrates a partial cross section acquired by cutting a pump housing according to the sixth embodiment along a plane including the central axis of the driving shaft.
- FIG. 1 illustrates a configuration of a hydraulic system to which a pump apparatus 1 is applied.
- the pump apparatus 1 is mounted on a vehicle of an automobile.
- the pump apparatus 1 is a hydraulic fluid supply source that supplies hydraulic fluid to another apparatus mounted on the vehicle (an apparatus mounted on a vehicle).
- the apparatus mounted on the vehicle to which the pump apparatus 1 supplies the hydraulic fluid is an automatic transmission.
- the automatic transmission is a stepless transmission, in particular, a belt-type continuously variable transmission (hereinafter referred to as a CVT) 10 .
- the hydraulic fluid is ATF (automatic transmission fluid).
- the pump apparatus 1 is driven by an internal-combustion engine as a prime mover thereof, and introduces and discharges the hydraulic fluid from and into an oil pan 100 .
- an oil pan of the CVT 10 can be used as the oil pan 100 .
- Various types of valves controlled by a CVT control unit are provided in a control valve of the CVT 10 .
- the hydraulic fluid discharged from the pump apparatus 1 is supplied to each unit (a primary pulley, a secondary pulley, a forward clutch, a reverse brake, a torque converter, a lubricant/cooling system, and the like) of the CVT 10 via the control valve.
- the pump apparatus 1 includes a pump housing 2 , a pump element 4 , a venturi portion 50 , and a control valve 8 .
- the pump housing 2 contains the pump element 4 , the control valve 8 , and the venturi portion 50 therein.
- An intake passage 3 , a discharge passage 5 , a high pressure passage 6 , an intermediate pressure passage 7 , and a return passage 9 are provided in the pump housing 2 as passages through which the hydraulic fluid flows.
- the intake passage 3 connects the oil pan 100 and the pump element 4 to each other.
- the discharge passage 5 connects the pump element 4 and the CVT 10 to each other.
- the venturi portion 50 is a constriction portion provided on the way along the discharge passage 5 .
- the high pressure passage 6 connects one side of the discharge passage 5 that is closer to the pump element 4 than the venturi portion 50 is (hereinafter referred to as an upstream side) and the control valve 8 to each other.
- the intermediate pressure passage 7 connects the venturi portion 50 and the control valve 8 to each other.
- the return passage 9 connects the control valve 8 and the intake passage 3 (the oil pan 100 ) to each other.
- a driving shaft 40 is pivotally supported in the pump housing 2 .
- the driving shaft 40 is driven by a crank shaft of the internal-combustion engine.
- the pump element 4 is rotationally driven by the driving shaft 40 .
- the pump element 4 introduces the hydraulic fluid therein from the oil pan 100 via the intake passage 3 .
- the pump element 4 discharges the hydraulic fluid to the discharge passage 5 , and supplies the hydraulic fluid to the CVT 10 via the discharge passage 5 .
- a relatively high pressure (hereinafter referred to as a high pressure) on the upstream side of the venturi portion 50 is fed into the control valve 8 via the high pressure passage 6 .
- a relatively low pressure (a pressure around an intermediate level, hereinafter referred to as an intermediate pressure) in the venturi portion 50 is fed into the control valve 8 via the intermediate pressure passage 7 .
- the control valve 8 switches a flow passage of the hydraulic fluid based on a difference (a differential pressure) between the pressure on the upstream side of the venturi portion 50 and the pressure in the venturi portion 50 . By this switching, the control valve 8 controls a flow amount of the hydraulic fluid that the pump element 4 supplies to the CVT 10 .
- FIG. 2 schematically illustrates a configuration of the pump apparatus 1 .
- FIG. 2 illustrates a cross section acquired by cutting the pump element 4 in a state extracted from the pump housing 2 along a plane perpendicular to a center axis (a rotational axis) O of the driving shaft 40 .
- FIG. 2 illustrates a partial cross section acquired by cutting the control valve 8 along a plane passing through a central axis thereof.
- FIG. 2 schematically illustrates each of the passages 3 and the like. A direction in which the hydraulic fluid flows is indicated by an arrowed alternate long and short dash line.
- FIG. 3 illustrates a partial cross section acquired by cutting the pump housing 2 along the plane perpendicular to the central axis O.
- FIG. 4 illustrates a cross section as viewed from a line A-A illustrated in FIG. 3 .
- An orthogonal coordinate system is set for convenience of the description.
- An x axis is set to a horizontal direction in FIG. 3 , and a positive side thereof is set to a right side in FIG. 3 .
- a y axis is set to a vertical direction in the sheet of FIG. 3 , and a positive side thereof is set to an upper side.
- a z axis is set to a direction perpendicular to the sheet of FIG. 3 , and a positive side thereof is set to a front side of the sheet.
- the driving shaft 40 (the central axis O) extends in the z-axis direction.
- the pump housing 2 includes a pump housing main body 20 and a venturi forming block 21 .
- the pump housing main body 20 is made from a metallic material.
- An intake port 230 and a discharge port 231 are formed at the pump housing main body 20 , besides each of the above-described passages 3 and the like.
- the venturi forming block 21 is made from a resin material.
- the venturi forming block 21 is a member separate from the pump housing main body 20 .
- the pump housing main body 20 includes a rear body 22 , a side plate 23 , and a front body.
- a containing recessed portion 220 , a first hole 221 , a second hole 222 , a third hole 223 , a fourth hole 224 , a fifth hole 225 , a discharge pressure chamber 226 , a valve containing hole 227 , a venturi forming block containing hole 228 , and a bearing holding hole are formed at the rear body 22 .
- the containing recessed portion 220 has a bottomed cylindrical shape.
- the containing recessed portion 220 extends in the z-axis direction and is opened on a positive side of the rear body 22 in the z-axis direction.
- first and second groove portions are formed on an inner peripheral surface of the containing recessed portion 220 so as to extend in the z-axis direction.
- the second groove portion is provided on an opposite side of a central axis of the containing recessed portion 220 from the first groove portion.
- the bearing holding hole (not illustrated) has a bottomed cylindrical shape. The bearing holding hole extends in the z-axis direction and is opened to a bottom portion of the containing recessed portion 220 on the negative side in the z-axis direction.
- a bearing is mounted on an inner periphery of the bearing holding hole.
- the discharge pressure chamber 226 is a bottomed recessed portion provided at the above-described bottom portion of the containing recessed portion 220 , and is opened to the above-described bottom portion.
- the first hole 221 extends in the y-axis direction on a negative side of the rear body 22 in the x-axis direction and a negative side of the rear body 22 in the z-axis direction.
- An opening of the first hole 22 on a negative side of the rear body 22 in the y-axis direction is sealingly closed by a plug member 221 a.
- the first hole 221 is formed so as to partially overlap the discharge pressure chamber 226 as viewed from the y-axis direction and the z-axis direction, and is connected to the discharge pressure chamber 226 .
- the valve containing hole 227 has a generally cylindrical shape, and extends in the x-axis direction on a positive side of the rear body 22 in the y-axis direction and a negative side of the rear body 22 in the z-axis direction.
- a longitudinal direction of the valve containing hole 227 extends perpendicularly to a direction along the central axis O (the z-axis direction).
- An end of the valve containing hole 227 on the positive side in the x-axis direction is opened on an outer surface of the rear body 22 . This opening is sealingly closed by a plug member 227 a.
- An end of the valve containing hole 227 on the negative side in the x-axis direction is connected to an end of the first hole 221 on the positive side in the y-axis direction.
- One end of the fifth hole 225 is opened on a portion of the valve containing hole 227 that is closer to the negative side in the x-axis direction.
- the other end of the fifth hole 225 is opened on the outer surface of the rear body 22 .
- the venturi forming block containing hole 228 has a generally cylindrical shape, and extends in the x-axis direction on the negative side of the rear body 22 in the z-axis direction.
- a longitudinal direction of the venturi forming block containing hole 228 (the x-axis direction) extends generally in parallel with the longitudinal direction of the valve containing hole 227 , and also extends perpendicularly to the direction along the central axis O (the z-axis direction).
- a negative side of the venturi forming block containing hole 228 in the x-axis direction is formed so as to intersect the first hole 221 and is connected to the first hole 221 .
- the negative side of the venturi forming block containing hole 228 in the x-axis direction is formed so as to partially overlap the discharge pressure chamber 226 as viewed from the y-axis direction and the z-axis direction, and is connected to the discharge pressure chamber 226 .
- An end of the venturi forming block containing hole 228 on the negative side in the x-axis direction is opened on the outer surface of the rear body 22 . This opening is sealingly closed by a plug member 228 a.
- the second hole 222 is provided on a generally same central axis as the venturi forming block containing hole 228 , and extends in the x-axis direction on a positive side of the rear body 22 in the x-axis direction and the negative side of the rear body 22 in the z-axis direction.
- An end of the second hole 222 on the negative side in the x-axis direction is connected to an end of the venturi forming block containing hole 228 on the positive side in the x-axis direction.
- An inner diameter of the second hole 222 is smaller than an inner diameter of the venturi forming block containing hole 228 .
- the third hole 223 extends in the z-axis direction on the positive side of the rear body 22 in the x-axis direction and the negative side of the rear body 22 in the z-axis direction.
- An end of the third hole 223 on the positive side in the z-axis direction is connected to an end of the second hole 222 on the positive side in the x-axis direction.
- An end of the third hole 223 on the negative side in the z-axis direction is opened on the outer surface of the rear body 22 .
- the fourth hole 224 connects a positive side of the valve containing hole 227 in the x-axis direction and a positive side of the venturi forming block containing hole 228 in the x-axis direction to each other.
- the side plate 23 has a disk-like shape.
- a shaft containing hole (not illustrated) is provided at the side plate 23 .
- the shaft containing hole penetrates through a central portion of the side plate 23 .
- a pair of intake ports 230 a and 230 b and a pair of discharge ports 231 a and 231 b are provided on a surface of the side plate 23 on one side in an axial direction.
- the pair of intake ports 230 a and 230 b is grooves extending in a generally circular-arc manner in a direction around the shaft containing hole (hereinafter referred to as a circumferential direction), and is provided at positions opposite of the shaft containing hole from each other.
- the pair of discharge ports 231 a and 231 b is grooves extending in a generally circular-arc manner in the circumferential direction, and is provided at positions opposite of the shaft containing hole from each other.
- the intake ports 230 and the discharge ports 231 are arranged alternately in the circumferential direction.
- a communication passage (not illustrated) is provided at the side plate 23 .
- the communication passage axially penetrates though the side plate 23 to establish communication between both side surfaces thereof.
- a first communication passage is opened to the intake port 230 .
- a second communication passage is opened to the discharge port 231 .
- the side plate 23 is installed in the containing recessed portion 220 of the rear body 22 .
- a surface of the side plate 23 on the above-described one side faces an opening side of the containing recessed portion 220 (the positive side in the z-axis direction).
- a surface of the side plate 23 on the other side faces the bottom portion of the containing recessed portion 220 .
- the shaft containing hole of the side plate 23 faces the bearing holding hole of the rear body 22 .
- the first communication passage of the side plate 23 faces the bearing holding hole of the rear body 22 .
- the first communication passage of the side plate 23 is connected to the intake passage 3 of the rear body 22 .
- Each of the intake ports 230 is connected to the intake passage 3 via the first communication passage.
- the second communication passage of the side plate 23 is connected to the discharge pressure chamber 226 of the rear body 22 .
- Each of the discharge ports 231 is connected to the discharge pressure chamber 226 via the second communication passage.
- a front body (not illustrated) is a pump cover.
- the front body is fixed to the positive side of the rear body 22 in the z-axis direction so as to sealingly close the containing recessed portion 220 .
- a bearing holding hole is provided at the front body 24 .
- the bearing holding hole extends in the z-axis direction.
- a bearing is mounted on an inner periphery of the bearing holding hole. An end of the driving shaft 40 on the positive side in the z-axis direction is inserted on the inner peripheral side of the bearing, and is rotatably mounted.
- the venturi forming block 21 has a generally cylindrical shape.
- a diameter (an outer diameter) of an outer peripheral surface of the venturi forming block 21 is approximately equal to a diameter (an inner diameter) of an inner peripheral surface of the venturi forming block containing hole 228 .
- the venturi portion 50 is formed at the venturi forming block 21 .
- the venturi portion 50 is a constriction portion formed at the venturi forming block 21 by molding.
- the venturi forming block 21 is joined to the pump housing main body 20 after the venturi portion 50 is formed.
- FIGS. 3 and 4 illustrate the cross section acquired by cutting the venturi forming block 21 along the plane passing through the axis line (the central axis) along a longitudinal direction of the venturi portion 50 .
- the venturi forming block 21 includes an inner diameter gradually-reducing portion 210 , the venturi portion 50 , a communication hole 213 , a first communication groove 214 , and a second communication groove 215 .
- the venturi portion 50 includes a small diameter portion 51 and an inner diameter gradually-increasing portion 52 .
- the inner diameter gradually-reducing portion 210 is provided so as to extend in the axial direction toward an inner peripheral side of the venturi forming block 21 , and is opened on an end surface of the venturi forming block 21 on one side in the axial direction.
- the inner diameter gradually-reducing portion 210 is a taper portion tapering from the one side in the axial direction toward the other side in the axial direction (a downstream side in the discharge passage 5 ), and is formed in such a manner that an inner diameter thereof gradually reduces toward the other side in the axial direction.
- An inner diameter of an end of the inner diameter gradually-reducing portion 210 on the one side in the axial direction is smaller than an inner diameter of the venturi forming block containing hole 228 .
- the small diameter portion 51 is provided on the inner peripheral side of the venturi forming block 21 , and extends in the axial direction. An end of the small diameter portion 51 on the one side in the axial direction is connected to an end of the inner diameter gradually-reducing portion 210 on the other side in the axial direction. An inner diameter of the small diameter portion 51 is approximately equal to an inner diameter of an end of the inner diameter gradually-reducing portion 210 on the other side in the axial direction, and is kept constant in the axial direction.
- the inner diameter gradually-increasing portion 52 is provided so as to extend in the axial direction on the inner peripheral side of the venturi forming block 21 .
- An end of the inner diameter gradually-increasing portion 52 on the one side in the axial direction is connected to an end of the small diameter portion 51 on the other side in the axial direction, and an end of the inner diameter gradually-increasing portion 52 on the other side in the axial direction is opened on an end surface of the venturi forming block 21 on the other side in the axial direction.
- the inner diameter gradually-increasing portion 52 is a taper portion tapering from the other side in the axial direction toward the one side in the axial direction (the upstream side of the discharge passage 5 ), and is formed in such a manner that an inner diameter thereof gradually increases from the one side in the axial direction toward the other side in the axial direction (the downstream side of the discharge passage 5 ).
- An inner diameter of the end of the inner diameter gradually-increasing portion 52 on the other side in the axial direction is slightly smaller than the inner diameter of the second hole 222 .
- the venturi forming block 21 is formed in such a manner that a narrower angle e sandwiched between inner walls of the inner diameter-gradually increasing portion 52 (one of angles sandwiched between the inner walls as viewed from a direction perpendicular to the central axis of the venturi portion 50 that is equal to or smaller than 180 degree) is 60 degrees or smaller, in particular, approximately 15 degrees.
- the communication hole 213 is a radial hole formed inside the venturi forming block 21 and extending in a radial direction of the venturi forming block 21 .
- a plurality of (four) communication holes 213 are provided, and are arranged at approximately equal intervals to one another in the circumferential direction.
- Each of the communication holes 213 is provided at a position overlapping the small diameter portion 51 in the axial direction.
- a radially inner end of each of the communication holes 213 is opened to the small diameter portion 51 .
- the first communication groove 214 is a circumferential groove formed on an outer peripheral surface of the venturi forming block 21 and extending in the circumferential direction. The first communication groove 214 is provided at a position overlapping the small diameter portion 51 and the communication hole 213 in the axial direction.
- the second communication groove 215 is an axial groove formed on the outer peripheral surface of the venturi forming block 21 and extending in the axial direction. An end of the second communication groove 215 on the one side in the axial direction is connected to the first communication groove 214 . An end of the second communication groove 215 on the other side in the axial direction is positioned close to the end surface of the venturi forming block 21 on the other side in the axial direction.
- the venturi forming block 21 is joined to the pump housing main body 20 (the venturi forming block containing hole 228 of the rear body 22 ) as illustrated in FIGS. 3 and 4 after the venturi portion 50 is formed.
- the central axis of the venturi forming block 21 (the venturi portion 50 ) extends in the x-axis direction.
- the above-described one side of the venturi forming block 21 in the axial direction corresponds to the negative side in the x-axis direction
- the above-described other side of the venturi forming block 21 in the axial direction corresponds to the positive side in the x-axis direction.
- the end surface of the venturi forming block 21 on the other side in the axial direction (on which the inner diameter gradually-increasing portion 52 is opened) is in abutment with the end surface of the venturi forming block containing hole 228 on the positive side in the x-axis direction (on which the second hole 222 is opened).
- the end of the second communication groove 215 in the venturi forming block 21 on the above-described other side in the axial direction is connected to an opening of the fourth hole 224 in the venturi forming block containing hole 228 .
- a third communication groove connected to the end of the second communication groove 215 on the other side in the axial direction and also extending in the circumferential direction may be provided at a position in the axial direction that radially faces the opening of the fourth hole 224 on the outer peripheral surface of the venturi forming block 21 .
- the end of the second communication groove 215 on the other side in the axial direction and the opening of the fourth hole 224 are connected to each other via the third communication groove, which eliminates a necessity of adjusting a position of the venturi forming block 21 in a rotational direction around the central axis of the venturi forming block containing hole 228 .
- the pump element 4 is contained in a space surrounded by the inner periphery of the containing recessed portion 220 in the rear body 22 , the surface of the side plate 23 on the positive side in the z-axis direction, and the surface of the front body on the negative side in the z-axis direction.
- the above-described space functions as a pump element containing portion.
- the driving shaft 40 is mounted in the above-described space, and the pump element 4 forms a plurality of pump chambers 400 around the driving shaft 40 .
- the pump element 4 is a vane pump-type pump, and includes a set of a rotor 41 and vanes 42 .
- the rotor 41 is provided in the pump element containing portion, and is coupled with the driving shaft 40 by serration coupling.
- the rotor 41 is rotationally driven by the driving shaft 40 , and rotates according to a rotation of the driving shaft 40 .
- a plurality of (ten) slits 410 (radially extending grooves) is each radially provided at the rotor 41 .
- the slits 410 are each opened on an outer peripheral surface of the rotor 41 .
- the plurality of slits 410 are provided at approximately equal intervals in a circumferential direction of the rotor 41 .
- the vane 42 is set in each of the slits 410 .
- the vane 42 is a generally rectangular plate member (a vane).
- the vane 42 is provided so as to be able to project from the slit 410 and retract into the slit 410 (provided in a projectable and retractable manner).
- a cam ring 43 has an annular shape. An outer periphery of the cam ring 43 is fitted in the inner periphery of the containing recessed portion 220 . A center (a central axis) of the cam ring 43 approximately coincides with the central axis O. An inner peripheral surface of the cam ring 43 has a cylindrical shape extending in the z-axis direction, and is generally ecliptic as viewed from the z-axis direction. Semi-cylindrical first and second groove portions 431 and 432 are provided on an outer peripheral surface of the cam ring 43 . The second groove portion 432 is provided on an opposite side of the central axis O of the cam ring 43 from the first groove portion 431 .
- a first pin 451 is mounted by being fitted between the above-described first groove portion of the containing recessed portion 220 and the first groove portion 431 of the cam ring 43 .
- a second pin 452 is mounted by being fitted between the above-described second groove portion of the containing recessed portion 220 and the second groove portion 432 of the cam ring 43 .
- Each of the pins 451 and 452 is fixed to the pump housing main body 20 .
- the pints 451 and 452 prevent or reduce a rotation of the cam ring 43 relative to the pump housing 2 .
- the cam ring 43 is disposed around the rotor 41 in the pump element containing portion.
- the cam ring 43 forms the plurality of pump chambers 400 together with the rotor 41 and the vanes 42 .
- the side plate 23 and the front body 24 are disposed on side surfaces of the cam ring 43 and the rotor 41 in the axial direction.
- a space between an inner peripheral surface of the cam ring 43 and an outer peripheral surface of the rotor 41 is sealingly closed by the side plate 23 and the front body 24 on the both sides thereof in the axial direction, while being divided into the plurality of (ten) pump chambers (volume chambers) 400 by the plurality of vanes 42 .
- an X axis and a Y axis are set to a long-axis direction and a short-axis direction of the generally ecliptic inner peripheral surface of the cam ring 43 , respectively, as illustrated in FIG. 2 .
- the rotor 41 rotates in a counterclockwise direction in FIG. 2 .
- a radial distance between the outer peripheral surface of the rotor 41 and the inner peripheral surface of the cam ring 43 (a radial dimension of the pump chamber 400 ) increases as approaching the negative side in the X-axis direction from the central axis O of the cam ring 43 , or approaching the positive side in the X-axis direction from the central axis O.
- the vane 42 projects from the slit 410 according to this change in the distance, by which each of the pump chambers 400 is defined.
- a volume of the pump chamber 400 increases as approaching the negative side in the X-axis direction from the central axis O or approaching the positive side in the X-axis direction from the central axis O.
- the volume of the pump chamber 400 reduces on the positive side in the X-axis direction with respect to the central axis O while increasing on the negative side in the X-axis direction with respect to the central axis O, as the rotor 41 rotates (as the pump chamber 400 travels toward the negative side in the x-axis direction) on the positive side in the Y-axis direction with respect to the central axis O.
- the volume of the pump chamber 400 reduces on the negative side in the X-axis direction with respect to the central axis O while increasing on the positive side in the X-axis direction with respect to the central axis O, as the rotor 41 rotates (the pump chamber 400 travel toward the positive side in the X-axis direction) on the negative side in the Y-axis direction with respect to the central axis O.
- the intake port 230 is opened to a region on the negative side in the X-axis direction and the positive side in the Y-axis direction, and a region on the positive side in the X-axis direction and the negative side in the Y-axis direction.
- the intake port 230 is opened to an intake region where the volume of the pump chamber 400 increases according to the rotation of the driving shaft 40 (i.e., an intake region where the pump chamber 400 increasing in volume according to the rotation of the driving shaft 40 among the plurality of pump chambers 400 is located).
- the discharge port 231 is opened to a region on the positive side in the X-axis direction and the positive side in the Y-axis direction, and a region on the negative side in the X-axis direction and the negative side in the Y-axis direction.
- the discharge port 231 is opened to a discharge region where the volume of the pump chamber 400 reduces according to the rotation of the driving shaft 40 (i.e., a discharge region where the pump chamber 400 reducing in volume according to the rotation of the driving shaft 40 among the plurality of pump chambers 400 is located).
- the pump chamber 400 introduces the hydraulic fluid therein from the intake port 230 in the intake region, and discharges the (above-described introduced) hydraulic fluid into the discharge port 231 in the discharge region.
- the intake and the discharge are each carried out twice per rotation of the driving shaft 40 in correspondence with the pair of intake ports 230 a and 230 b and the pair of discharge ports 231 a and 231 b.
- the hydraulic fluid in both the discharge ports 231 are collected into one portion.
- the cam ring 43 is provided immovably in the pump element containing portion.
- the pump element 4 is a fixed displacement pump that discharges a constant amount as a discharge amount per rotation of the driving shaft 40 (hereinafter referred to as a pump capacity).
- the pump element 4 may be a set of trochoidal pump-type inner and outer rotors or may be another type of pump.
- the control valve 8 is a spool valve body and is contained in the valve containing hole 227 .
- the control valve 8 is displaceable (capable of performing a stroke) in the x-axis direction in the valve containing hole 227 .
- the control valve 8 includes a first land portion 81 , a second land portion 82 , a connection portion 83 , a spacer portion 84 , and a recessed portion 85 .
- Each of the land portions 81 and 82 is cylindrical, and diameters thereof are approximately equal to each other.
- a diameter of an outer peripheral surface of each of the land portions 81 and 82 is slightly smaller than a diameter of an inner peripheral surface of the valve containing hole 227 .
- the first land portion 81 is provided on the negative side in the x-axis direction and the second land portion 82 is provided at an end on the positive side in the x-axis direction.
- a circumferential groove 810 extending in a direction around the central axis of the control valve 8 (hereinafter referred to as a circumferential direction) is provided on an outer peripheral surface of the first land portion 81 .
- a plurality of circumferential grooves 820 extending in the circumferential direction is provided on an outer peripheral surface of the second land portion 82 .
- the connection portion 83 has a cylindrical shape sandwiched between both the land portions 81 and 82 and extending in the x-axis direction.
- a diameter of the outer peripheral surface of the connection portion 83 is smaller than each of the land portions 81 and 82 .
- the spacer portion 84 has a rod shape extending from the first land portion 81 toward the negative side in the x-axis direction.
- the recessed portion 85 has a bottomed cylindrical shape and extends in the x-axis direction inside the second land portion 82 .
- the recessed portion 85 is opened on an end surface of the second land portion 82 on the positive side in the x-axis direction.
- a high pressure chamber 86 is defined inside the valve containing hole 227 by being surrounded by an end surface of the first land portion 81 on the negative side in the x-axis direction and the inner peripheral surface of the valve containing hole 227 .
- An intermediate pressure chamber 88 is defined by being surrounded by an end surface of the second land portion 82 on the positive side in the x-axis direction, the inner peripheral surface of the valve containing hole 227 , and an end surface of the plug member 227 a on the negative side in the x-axis direction.
- a drain chamber 89 is defined on an outer periphery of the connection portion 83 between the first land portion 81 and the second land portion 82 .
- a spring 88 is mounted in the intermediate pressure chamber 88 .
- the spring 88 is a coil spring. An end of the spring 88 on the positive side in the x-axis direction is held by the plug member 227 a. A negative side of the spring 88 in the x-axis direction is held inside the recessed portion 85 of the control valve 8 . The spring 88 is mounted in a compressed state. The spring 88 is a return spring constantly biasing the control valve 8 toward the negative side in the x-axis direction.
- a displacement of the control valve 8 in the valve containing hole 227 toward the negative side in the x-axis direction is regulated by abutment of an end of the spacer portion 84 on the negative side in the x-axis direction with an end surface of the valve containing hole 227 on the negative side in the x-axis direction.
- the first hole 221 is opened to the high pressure chamber 86 and the fourth hole 224 is opened to the intermediate pressure chamber 88 , regardless of the displacement of the control valve 8 in the valve containing hole 227 .
- Each of the discharge ports 231 of the side plate 23 is in communication with the first hole 221 or the venturi forming block containing hole 228 via the discharge pressure chamber 226 of the rear body 22 .
- the small diameter portion 51 is formed in such a manner that the inner diameter thereof is smaller than an inner diameter of the above-described discharge passage 5 .
- the inner diameter gradually-increasing portion 52 of the venturi portion 50 is in communication with outside the rear body 22 via the second hole 222 and the third hole 223 .
- the second hole 222 and the third hole 223 function as the discharge passage 5 extending from the venturi portion 50 toward the CVT 10 , i.e., the discharge passage 5 on the downstream side of the venturi portion 50 .
- An inner diameter of the above-described discharge passage 5 is larger than an inner diameter of an end of the inner diameter gradually-increasing portion 52 on the positive side in the x-axis direction.
- the communication hole 213 , the first communication groove 214 , and the second communication groove 215 of the venturi forming block 21 , and the fourth hole 224 of the rear body 22 function as the intermediate pressure passage 7 (a venturi portion pressure introduction passage) branching off from the venturi portion 50 (the small diameter portion 51 ) in the discharge passage 5 and is connected to the intermediate pressure chamber 88 of the control valve 8 .
- the communication hole 213 functions as a venturi portion pressure introduction hole.
- the fifth hole 225 of the rear body 22 functions as the return passage 9 extending from the drain chamber 89 of the control valve 8 toward the oil pan 100 .
- the longitudinal direction of the venturi portion 50 extends generally perpendicularly to the direction in which the central axis O of the driving shaft 40 extends (the z-axis direction), and also extends generally in parallel with the longitudinal direction of the control valve 8 (the x-axis direction).
- the venturi portion 50 is disposed in such a manner that the upstream side thereof faces the high pressure chamber 86 of the control valve 8 .
- the discharge passage 5 on the upstream side of the venturi portion 50 and the high pressure chamber 86 at least partially overlap each other in the x-axis direction.
- the negative side of the venturi forming block containing hole 228 in the x-axis direction with respect to the venturi forming block 21 , and the high pressure chamber 86 (when the control valve 8 is maximally displaced toward the negative side in the x-axis direction) at least partially overlap each other as viewed from the y-axis direction.
- FIG. 6 schematically illustrates the discharge passage 5 around the venturi portion 50 .
- An arrow indicates the direction in which the hydraulic fluid flows. It is defined that u 1 and p 1 represent a flow speed and a pressure of the hydraulic fluid in the discharge passage 5 on the upstream side of the venturi portion 50 , respectively. It is defined that u 2 and p 2 represent a flow speed and a pressure at the small diameter portion 51 . It is defined that u 3 and p 3 represent a flow speed and a pressure in the discharge passage 5 on the downstream side of the venturi portion 50 , respectively.
- a lower diagram of FIG. 6 illustrates a change in the pressure P that is associated with each of the portions illustrated in the upper diagram.
- the inner diameter (a cross-sectional area) of the small diameter portion 51 is smaller than the inner diameter (a cross-sectional area) of the discharge passage 5 on the upstream side of the venturi portion 50 . Therefore, u 2 is higher than u 1 .
- This increase in the flow speed is proportional to the flow amount and inversely proportional to a difference in the cross-sectional area.
- the pressure reduces in a quadratic function manner according to the increase in the flow speed based on Bernoulli's principle. Therefore, p 2 is lower than p 1 . This reduction in the pressure corresponds to the increase in the flow speed, i.e., the flow amount.
- the inner diameter of the inner diameter gradually-increasing portion 52 gradually increases at the venturi portion 50 as approaching the downstream side. Therefore, the flow speed at the inner diameter gradually-increasing portion 52 gradually reduces as approaching the downstream side. Since the reduction in the flow speed is gentle, energy is not lost so much. Therefore, the pressure in the inner diameter gradually-increasing portion 52 gradually increases as the hydraulic fluid flows toward the downstream side, according to the reduction in the flow speed.
- the flow speed reduces to around u 1 , and the pressure increases (recovers) to around p 1 . Since the inner diameter of the constriction portion on the downstream side (the inner diameter gradually-increasing portion 52 ) gently increases in this manner, a large loss of energy is prevented or cut down. Therefore, on the downstream side of the constriction portion, the flow speed reduces to a similar level to the upstream side of the constriction portion, and the pressure also recovers to a similar level to the upstream side of the constriction portion.
- the hydraulic fluid (p 1 ) on the upstream side of the venturi portion 50 is introduced into the high pressure chamber 86 via the high pressure passage 6 .
- the hydraulic fluid (p 2 ) in the venturi portion 50 (the small diameter portion 51 ) is introduced into the intermediate pressure chamber 88 via the intermediate pressure passage 7 .
- the drain chamber 89 is kept at the low pressure (is opened to an atmospheric pressure similarly to the intake passage 3 ).
- a force F 1 toward the positive side in the x-axis direction due to pi in the high pressure chamber 86 and a force F 2 toward the negative side in the x-axis direction due to p 2 in the intermediate pressure chamber 88 are applied to the control valve 8 .
- a force F 3 toward the negative side in the x-axis direction due to the spring 88 is applied to the control valve 8 .
- F 1 ⁇ F 2 the force corresponding to the differential pressure ⁇ p
- the control valve 8 is displaced toward the positive side in the x-axis direction.
- the hydraulic fluid introduced from the discharge passage 5 on the upstream side of the venturi portion 50 to the high pressure passage 6 (the high pressure chamber 86 ) starts to be returned to the intake passage 3 (one side where the intake ports 230 are located) via the return passage 9 .
- the control valve 8 switches the flow passage in such a manner that the hydraulic fluid is returned toward the intake side based on the differential pressure ⁇ p between the upstream side of the venturi portion 50 and the small diameter portion 51 .
- the flow amount to be supplied to the CVT 10 via the discharge passage 5 is limited to a required amount.
- the venturi portion 50 , the high pressure passage 6 , the intermediate pressure chamber 7 , the control valve 8 , and the return passage 9 function as a controller that controls the discharge flow amount of the pump element 4 .
- the orifice has been used as a means for generating the differential pressure.
- the orifice can be formed with, for example, such a simple structure that only a constriction of a thin plate is provided in the flow passage.
- the pressure difference is generated according to the flow amount between the upstream side and the downstream side of the orifice.
- the orifice leads to a turbulence of the flow at an exit of the constriction, thereby resulting in a loss of the energy and thus a reduction in the pressure on the downstream side of the orifice.
- the lost energy undesirably spreads outward by being converted into heat, noise, and the like. Therefore, the efficiency of the pump undesirably reduces.
- FIG. 7 is a similar diagram to FIG. 6 that illustrates the comparative example.
- An upper diagram of FIG. 7 illustrates the discharge passage 5 around the orifice 500 . It is defined that u 1 and p 1 represent the flow speed and the pressure of the hydraulic fluid in the discharge passage 5 on the upstream side of the orifice 500 , respectively.
- u 2 and p 2 represent the flow speed and the pressure in the discharge passage 5 on the downstream side of the orifice 500 , respectively.
- An inner diameter of the orifice 500 is smaller than the inner diameter of the discharge passage 5 on the upstream side of the orifice 500 . Therefore, the flow speed at the orifice 500 is higher than and the pressure at the orifice 500 is lower than p 1 .
- An inner diameter of the exit of the orifice 500 suddenly increases as approaching the downstream side. Therefore, an eddy current occurs at the exit of the orifice 500 , and the energy is significantly lost. Therefore, although u 2 reduces to u 1 , p 2 does not increase (recover) to p 1 . In other words, the pressure undesirably reduces (a pressure loss).
- the conventional pump apparatus results in supply of the pressure p 2 to the CTV 10 after the pressure reduces in this manner.
- the pump apparatus 1 uses a venturi tube instead of the orifice as method means for generating the differential pressure.
- the venturi portion 50 has the gently increasing inner diameter on the downstream side (the inner diameter gradually-increasing portion 52 ) of the constriction portion, thereby preventing or cutting down the significant loss of the energy. Therefore, the pressure recovers according to the reduction in the flow speed. In other words, the pressure loss at a differential pressure generation means is prevented or cut down. Therefore, the present embodiment can generate the differential pressure while preventing or reducing the deterioration of the efficiency of the pump.
- the automatic transmission such as the stepless transmission uses a larger flow amount compared to a power steering apparatus and the like, and therefore can acquire a considerable effect of preventing or cutting down the pressure loss.
- An entrance at the constriction portion at the venturi portion 50 (the upstream side of the small diameter portion 51 ) is also formed in such a manner that the dimeter of the inner diameter gradually-reducing portion 210 gently reduces, which can prevent or reduce the occurrence of the turbulence of the flow.
- the present embodiment can further efficiently reduce the pressure (can prevent or cut down the pressure loss as a whole). Therefore, the present embodiment can further improve the efficiency of the pump.
- the present embodiment can increase the differential pressure (the force F 1 ⁇ F 2 corresponding thereto) while preventing or reducing the deterioration of the efficiency of the pump.
- FIG. 8 is a graph indicating a relationship between the discharge flow amount (the flow amount passing through the differential pressure generation means) Q of the pump element 4 , and the difference ⁇ p between the pressures applied to the both sides of the control valve 8 in the axial direction (the differential pressure generated at the differential pressure generation means). Supposing that the efficiency of the pump (the pressure loss at the differential pressure generation means) is the same between the present embodiment and the comparative example, a characteristic of the present embodiment is indicated by a solid line, and a characteristic of the comparative example is indicated by an alternate long and short dash line. According to Q, ⁇ p changes in a quadratic curve manner.
- the activation (displacement) of the control valve 84 is controlled according to ⁇ p, i.e., Q.
- a change rate of ⁇ p to Q is higher in the present embodiment than in the comparative example.
- Q required to generate the same level of ⁇ p is smaller in the present embodiment than in the comparative example.
- a larger pressure of ⁇ p (the force F 1 ⁇ F 2 corresponding thereto) can be generated in the present embodiment than in the comparative example even if Q is the same therebetween. Therefore, the present embodiment can stabilize the behavior of the control valve 8 , and prevent or reduce the variation in the control flow amount.
- a load from outside may be applied to the control valve 8 besides F 1 to F 3 .
- the control flow amount may deviate from an originally intended amount.
- the differential pressure ⁇ p (the force F 1 ⁇ F 2 corresponding thereto) can be considerably changed with a small change in the flow amount Q. Therefore, the deviation of the control amount can be reduced.
- ⁇ p represents the above-described load converted into ⁇ p
- ⁇ Q represents the deviation of Q corresponding to this ⁇ p.
- a predetermined amount of Q corresponds to an arbitrary pressure of ⁇ p
- a deviation of the above-described arbitrary pressure of ⁇ p by ⁇ p causes a deviation of Q from the above-described predetermined amount of Q by ⁇ Q.
- the change rate of Q to ⁇ p is smaller in the present embodiment than in the comparative example.
- ⁇ Q corresponding to the same deviation of ⁇ p is smaller in the present embodiment than in the comparative example ( ⁇ Q 2 ⁇ Q 1 ). In other words, even when the same load is applied to the control valve 8 , the flow amount is less changed in the present embodiment than in the comparative example. Therefore, the present embodiment can reduce the deviation of the control flow amount.
- the present embodiment can generate a large differential pressure ⁇ p with a relatively small flow amount Q while preventing or cutting down the energy loss at the constriction portion. Therefore, the diameter of the control valve 8 can be reduced without requiring a significant reduction in the force F 1 ⁇ F 2 applied to the control valve 8 .
- Reducing the diameter of the control valve 8 also allows a reduction in the gap area of the above-described clearance portion.
- the present embodiment reduces the leak amount around the control valve 8 , thereby succeeding in preventing or reducing the deterioration of the pump efficiency.
- the narrower angle e sandwiched between the inner walls of the inner diameter gradually-increasing portion 52 is an angle by which the exit flares at the venturi portion 50 as the constriction portion.
- Setting ⁇ to 60 degrees or smaller can acquire a sufficient effect of preventing or cutting down the pressure loss.
- FIG. 9 illustrates a relationship between ⁇ and a pressure loss rate.
- the pressure loss rate is a rate when the pressure rate in the comparative example is defined to be 1. When ⁇ is 60 degrees or smaller, the pressure loss rate falls below 1. In other words, the pressure loss is smaller than the comparative example.
- the venturi portion 50 (the inner diameter gradually-increasing portion 52 ) is formed in such a manner that ⁇ becomes 60 degrees or smaller.
- the present embodiment can further reliably prevent or reduce the deterioration of the pump efficiency. For example, by setting ⁇ to approximately 15 degrees, the present embodiment can prevent or cut down an excessive increase in the length of the venturi portion 50 in the longitudinal direction (a dimension in the axial direction) while acquiring a sufficiency effect of preventing or cutting down the pressure loss.
- the space in the venturi forming block containing hole 228 on the negative side in the x-axis direction with respect to the venturi forming block 21 functions as the discharge passage 5 on the upstream side of the venturi portion 50 .
- the second hole 222 functions as the discharge passage 5 on the downstream side of the venturi portion 50 .
- the inner diameter of the venturi forming block containing hole 228 is larger than the inner diameter of the second hole 222 .
- the above-described space in the discharge passage 5 on the upstream side of the venturi portion 50 is a large diameter portion 53 having a larger inner diameter than the downstream side (the second hole 222 ).
- FIG. 6 can be redrawn like FIG. 10 .
- u 1 * and p 1 * represent a flow speed and a pressure in the large diameter portion 53 .
- the other symbols are similar to FIG. 6 . If the inner diameter (the cross-sectional area) of the large diameter portion 53 is larger than the inner diameter (the cross-sectional area) of the discharge passage 5 on the upstream side of the large diameter portion 53 , u 1 * is lower than u 1 ( ⁇ u 3 ). According thereto, p 1 * is higher than p 1 ( ⁇ p 3 ).
- ⁇ p* represents the differential pressure generated at the venturi portion 50 (the small diameter portion 51 )
- the difference F 1 ⁇ F 2 between the forces applied to the control valve 8 increases, so that the present embodiment can further effectively acquire the above-described functions and effects.
- the inner diameter of the end of the inner diameter gradually-increasing portion 52 on the other end in the axial direction that is opened on the end surface of the venturi forming block 21 on the other side in the axial direction is slightly smaller than the inner diameter of the second hole 222 . Therefore, FIG. 6 can be redrawn like FIG. 11 .
- the inner diameter gradually-increasing portion 52 includes the taper portion on the upstream side that is formed so as to keep ⁇ constant at 60 degrees or smaller (in particular, approximately 15 degrees), and a stepped portion on the downstream side that is formed so as to have ⁇ larger than 60 degrees continuously from the discharge passage 5 on the downstream side of the venturi portion 50 .
- the inner diameter gradually-increasing portion 52 includes the front portion 520 and the rear portion 521 .
- ⁇ of the rear portion 521 is approximately 180 degrees.
- the rear portion 521 flares as if extending generally perpendicularly to the inner walls of the discharge passage 5 on the downstream side of the venturi portion 50 .
- L 0 is defined to represent a length of this (hypothetical) inner diameter gradually-increasing portion 52 in the longitudinal direction at this time. Then, L is defined to represent a length of the front portion 520 in the longitudinal direction.
- FIG. 12 illustrates a relationship between L/L 0 , which is a ratio of L to L 0 , and the pressure loss rate.
- the pressure loss rate is a rate of a pressure loss when L/L 0 is 0, i.e., a rate when the pressure loss in the comparative example is defined to 1.
- L/L 0 is higher than 0 and equal to or lower than 0.65
- the pressure loss rate reduces according to the increase in L/L 0 .
- the pressure loss rate does not reduce more than that even when L/L 0 increases.
- the pressure loss can be more prevented or cut down than in the comparative example.
- the length L of the front portion 520 increases to longer than 65% of L 0 , this does not achieve the effect of preventing or cutting down the pressure loss more than that. Therefore, it is preferable to form the front portion 520 in such a manner that the L/L 0 exceeds 0 and reaches or falls below 0.65, i.e., as far as a position where L reaches or falls below 65% of L 0 .
- the rear portion 521 where ⁇ exceeds 60 degrees is provided on the downstream side of the front portion 520 .
- Stopping keeping ⁇ at 60 degrees or smaller at the rear portion 521 in this manner allows the venturi portion 50 to be formed continuously from the discharge passage 5 (the inner diameter of the venturi portion 50 to be returned to the initial diameter) on the downstream side, with a relatively short length (shorter than L 0 ).
- the present embodiment can reduce the length of the venturi portion 50 in the longitudinal direction.
- the present embodiment can improve the above-described effect of reducing the length by allowing ⁇ at the rear portion 521 to approach generally 180 degrees as illustrated in FIG. 11 .
- a reduction amount (a reduction rate) of the pressure loss rate with respect to the increase in L/L 0 increases as L/L 0 approaches 0.
- a sufficiently low pressure loss rate (sufficiently close to the pressure loss rate when L/L0 is 0.65) can be acquired. Therefore, it is preferable to form the front portion 520 in such a manner that L/L 0 reaches or exceeds 0.4, i.e., as far as a position where L reaches or exceeds 40% of L 0 .
- the present embodiment can improve the above-described effect of reducing the length by allowing L to approach 40% of L 0 while acquiring the sufficient effect of preventing or cutting down the pressure loss.
- the venturi portion 50 is long compared to the orifice (the dimension in the axial direction is large). Therefore, processing thereof is comparatively difficult.
- the venturi portion 50 is formed in the venturi forming block 21 .
- This venturi forming block 21 is joined to the pump housing main body 20 .
- the venturi portion 50 is realized inside the pump housing main body 20 .
- the present embodiment can improve workability of the venturi portion 50 by forming the venturi portion 50 in the venturi forming block 21 that is a separate member from the pump housing main body 20 .
- the present embodiment can be realized by forming at least the small diameter portion 51 and the inner diameter gradually-increasing portion 52 constituting the venturi portion 50 in the venturi forming block 21 .
- the constriction portion having the same diameter as the small diameter portion 51 and a predetermined length and the inner diameter gradually-reducing portion 210 may be provided on the pump housing main body 20 side, or may be provided on the venturi forming block 21 side.
- the venturi forming block 21 is made from the resin material.
- the venturi portion 50 including the inner diameter gradually-increasing portion 52 is formed by molding. Therefore, the inner diameter gradually-increasing portion 52 can be easily formed compared to forming the inner diameter gradually-increasing portion 52 by machining processing.
- venturi portion 50 should have a long dimension (a large space in the longitudinal direction) compared to the orifice.
- the venturi portion 50 is disposed in such a manner that the longitudinal direction of the venturi portion 50 (the x-axis direction) and the direction of the rotational axis (the central axis O) of the driving shaft 40 (the z-axis direction) extend generally perpendicularly to each other.
- the present embodiment can prevent or cut down an increase in the dimension of the pump apparatus in the direction of the rotational axis of the driving shaft 40 (the axial direction).
- the pump housing 2 has a dimension enough to contain the control valve 8 therein from the beginning.
- the venturi portion 50 is disposed in such a manner that the longitudinal direction of the venturi portion 50 and the longitudinal direction of the control valve 8 extend generally in parallel with each other.
- the venturi portion 50 is disposed so as to utilize the originally existing space extending in the longitudinal direction of the control valve 8 in this manner, so that the present embodiment can prevent or cut down the increase in a size of an outer shape of the pump apparatus (in the radial direction of the control valve 8 ).
- venturi portion 50 is disposed in such a manner that the discharge passage 5 on the upstream side of the venturi portion 50 faces the high pressure chamber 86 of the control valve 8 . Therefore, the present embodiment can shorten the high pressure passage 6 (the first hole 221 ) establishing the communication between the upstream side of the venturi portion 50 and the high pressure chamber 86 . More specifically, both the venturi forming block containing hole 228 and the valve containing hole 227 extend in the x-axis direction and are disposed generally in parallel with each other.
- the first hole 221 extends linearly in the y-axis direction, and connects the negative side of the venturi forming block containing hole 228 in the x-axis direction with respect to the venturi forming block 21 and the high pressure chamber 86 in the valve containing hole 227 to each other, thereby connecting the upstream side of the venturi portion 50 and the high pressure chamber 86 with a shortest distance.
- the venturi portion 50 may be disposed in such a manner that the second communication groove 215 (at least a part thereof) in the venturi forming block 21 faces the intermediate pressure chamber 88 of the control valve 8 . In this case, the present embodiment can shorten the intermediate pressure passage 7 (the fourth hole 224 ) establishing the communication between the second communication groove 215 and the intermediate pressure chamber 88 .
- the communication holes 213 of the venturi forming block 21 are opened on the inner peripheral surface of the venturi portion 50 on the radially inner side.
- the communication holes 213 are provided in the venturi portion 50 , and function as openings for introducing the pressure in the venturi portion 50 into the control valve 8 (the intermediate pressure chamber 88 ).
- this passage 5 may have unevenness in a flow speed distribution in a direction around the axis line along the longitudinal direction thereof(hereinafter referred to as a circumferential direction). This case also leads to occurrence of unevenness in a pressure distribution in the circumferential direction in the venturi portion 50 .
- the plurality of (four) openings is provided in the circumferential direction of the venturi portion 50 as the above-described openings of the communication holes 213 .
- the pressure is extracted from a plurality of portions in the circumferential direction in the venturi portion 50 in this manner, which allows the pressure in the venturi portion 50 to be stably introduced into the intermediate pressure chamber 88 in spite of the above-described unevenness in the pressure distribution.
- the pressures (the hydraulic fluid) extracted from the above-described openings of the plurality of communication holes 213 are collected into the single intermediate pressure passage 7 (the fourth hole 224 ) via the first and second communication grooves 214 and 215 , and then are introduced into the intermediate pressure chamber 88 .
- the above-described uneven pressure distributions are canceled out by each other, which results in introduction of an average pressure in the circumferential direction in the venturi portion 50 into the intermediate pressure chamber 88 . Therefore, the variation in the pressure extracted from inside the venturi portion 50 is reduced. Therefore, the activation of the control valve 8 is stabilized, and the deviation of the control flow amount is reduced.
- the number of communication holes 213 may be any number as long as this number is two or more.
- the above-described openings of the communication holes 213 are disposed at generally equal intervals in the circumferential direction, so that the present embodiment can further stably reduce the variation in the pressure extracted from inside the venturi portion 50 .
- the communication holes 213 are provided at the positions overlapping the small diameter portion 51 in the axial direction (the longitudinal direction) of the venturi portion 50 .
- the above-described openings of the communication holes 213 are provided at the small diameter portion 51 . Therefore, this configuration results in extraction of the pressure from a portion smallest in diameter in the venturi portion 50 , i.e., a portion in the venturi portion 50 where the pressure is minimized, and introduction of this pressure into the intermediate pressure chamber 88 .
- the present embodiment can most efficiently utilize the differential pressure generated in the venturi portion 50 .
- the pump apparatus 1 according to a second embodiment is different from the first embodiment in terms of the configuration of the venturi forming block 21 .
- the second embodiment will be described below focusing on only configurations different from the first embodiment. Configurations shared with the first embodiment will be identified by the same reference numerals as the first embodiment, and descriptions thereof will be omitted.
- FIG. 13 illustrates a cross section acquired by cutting the venturi forming block 21 along a plane passing through the central axis of the venturi portion 50 .
- the venturi forming block 21 is not provided with the inner diameter gradually-reducing portion 210 like the first embodiment.
- the small diameter portion 51 is opened on the end surface of the venturi forming block 21 on the one side in the axial direction (the outer surface of the venturi forming block 21 ).
- the communication hole 213 is provided at the position overlapping the one side of the inner diameter gradually-increasing portion 52 in the axial direction (the one side where the small diameter portion 51 is located). A radially inner end of the communication hole 213 is opened to the one side of the inner diameter gradually-increasing portion 52 in the axial direction (the one side where the small diameter portion 51 is located). The communication hole 213 forms a part of the intermediate pressure passage 7 . The communication hole 213 introduces a pressure on the one side of the inner diameter gradually-increasing portion 52 in the axial direction (the one side where the small diameter portion 51 is located) among pressures in the venturi portion 50 into the intermediate pressure chamber 88 of the control valve 8 .
- the pressure in the venturi portion 50 that is introduced into the intermediate pressure chamber 88 may be not only the pressure in the small diameter portion 51 but also the pressure in the inner diameter gradually-increasing portion 52 .
- the pressure on the one side of the inner diameter gradually-increasing portion 52 in the axial direction (the one side where the small diameter portion 51 is located) is introduced into the intermediate pressure chamber 88 . Therefore, a lower pressure among the pressures in the inner diameter gradually-increasing portion 52 can be used. Therefore, the present embodiment allows a sufficiently large differential pressure to be applied to the control valve 8 .
- the small diameter portion 51 is not opened on the outer surface of the venturi forming block 21 and is provided inside the venturi forming block 21 , a mold would have to be inserted from the both sides of the venturi forming block 21 in the axial direction when the venturi portion 50 is formed by molding.
- the venturi portion 50 is subjected to the machining processing, the machining processing would have to be performed from the both sides of the venturi forming block 21 in the axial direction.
- the small diameter portion 51 is opened on the outer surface of the venturi forming block 21 .
- venturi portion 50 when the venturi portion 50 is formed by molding, this can be achieved by inserting the mold only from the opening side of the inner diameter gradually-increasing portion 52 in the axial direction of the venturi forming block 21 .
- the venturi portion 50 when the venturi portion 50 is subjected to the machining processing, this can be achieved by performing the machining processing only from the opening side of the inner diameter gradually-increasing portion 52 in the axial direction of the venturi forming block 21 . Therefore, manufacturability of the venturi portion 50 (the venturi forming block 21 ) can be improved.
- the pump housing main body 20 is made from a metallic material similarly to the first embodiment.
- the venturi forming block 21 is also made from a metallic material unlike the first embodiment. More specifically, the venturi forming block 21 is made from a sintered material.
- the venturi portion 50 is formed with use of a mold when metallic powder is molded by being compacted in a powder compacting process. This compact is sintered, by which the venturi forming block 21 is formed.
- the venturi forming block 21 is joined to the pump housing main body 20 (the venturi forming block containing hole 228 of the rear body 22 )
- this configuration can raise a problem such as occurrence of a distortion between the venturi forming block 21 and the pump housing main body 20 after the venturi forming block 21 is joined to the pump housing main body 20 .
- the venturi forming block 21 is made from the metallic material. Therefore, the venturi forming block 21 has a similar linear expansion coefficient to the pump housing main body 20 . Therefore, the present embodiment can prevent or reduce occurrence of a problem like the above-described example.
- venturi portion 50 (the inner diameter gradually-increasing portion 52 and the like) is formed with use of the mold. Therefore, the venturi portion 50 can be easily formed compared to forming the venturi portion 50 (the inner diameter gradually-increasing portion 52 and the like) by the machining processing.
- the pump apparatus 1 according to a fourth embodiment is different from the first embodiment in terms of the layout of the venturi portion 50 and the like.
- the fourth embodiment will be described below focusing on only configurations different from the first embodiment. Configurations shared with the first embodiment will be identified by the same reference numerals as the first embodiment, and descriptions thereof will be omitted.
- FIG. 14 illustrates the pump housing 2 as viewed from the direction in which the driving shaft 40 (the central axis O) extends (as viewed from the negative side in the z-axis direction), and a part of an inner structure and contained components are indicated by broken lines.
- FIG. 15 illustrates a cross section as viewed from a line B-B illustrated in FIG. 14 .
- the pump housing 2 does not include the venturi forming block 21 like the first embodiment.
- the pump housing main body 20 does not include the venturi forming block containing hole 228 like the first embodiment.
- the inner diameter gradually-reducing portion 210 and the venturi portion 50 are directly formed inside the rear body 22 .
- the inner diameter gradually-reducing portion 210 and the venturi portion 50 extend in the z-axis direction on the positive side of the rear body 22 in the x-axis direction and the negative side of the rear body 22 in the y-axis direction.
- the longitudinal direction of the venturi portion 50 extends generally in parallel with the direction of the central axis O (the z-axis direction) and also extends perpendicularly to the longitudinal direction of the valve containing hole 227 (the x-axis direction).
- the venturi portion 50 does not overlap the containing recessed portion 220 in the direction perpendicular to the z axis (the radial direction of the rotational axis of the driving shaft 40 ) (the venturi portion 50 is located on the radially outer side with respect to the containing recessed portion 220 ), but overlaps the containing recessed portion 220 in the z-axis direction.
- the inner diameter gradually-reducing portion 210 includes a first inner diameter gradually-reducing portion 210 a where a narrower angle sandwiched between inner walls thereof is relatively large, and a second inner diameter gradually-reducing portion 210 b where a narrower angle thereof is relatively small.
- An end of the first inner diameter gradually-reducing portion 210 a on the positive side in the z-axis direction is opened on the surface of the rear body 22 on the positive side in the z-axis direction.
- An inner diameter of the first inner diameter gradually-reducing portion 210 a gradually reduces from the positive side toward the negative side in the z-axis direction.
- An end of the second inner diameter gradually-reducing portion 210 b on the positive side in the z-axis direction is connected to an end of the first inner diameter gradually-reducing portion 210 a on the negative side in the z-axis direction.
- An inner diameter of the second inner diameter gradually-reducing portion 210 b gradually reduces from the positive side toward the negative side in the z-axis direction.
- An end of the small diameter portion 51 on the positive side in the z-axis direction is connected to an end of the second inner diameter gradually-reducing portion 210 b on the negative side in the z-axis direction.
- An end of the small diameter portion 51 on the negative side in the z-axis direction is connected to an end of the inner diameter gradually-increasing portion 52 on the positive side in the z-axis direction.
- the inner diameter of the inner diameter gradually-increasing portion 52 gradually increases from the positive side toward the negative side in the z-axis direction.
- An end of the inner diameter gradually-increasing portion 52 on the negative side in the z-axis direction is opened on the surface of the rear body 22 on the negative side in the z-axis direction.
- the second hole 222 extends in the z-axis direction on the negative side of the rear body 22 in the x-axis direction and the negative side of the rear body 22 in the y-axis direction.
- An end of the second hole 222 on the negative side in the z-axis direction is connected to an end of the first hole 221 on the negative side in the y-axis direction.
- An end of the second hole 222 on the positive side in the z-axis direction is opened on the surface of the rear body 22 on the positive side in the z-axis direction.
- the third hole 223 is formed inside the front body 24 and is disposed so as to extend in the x-axis direction.
- An end of the third hole 223 on the negative side in the x-axis direction is bent toward the negative side in the z-axis direction and opened on the surface of the front body 24 on the negative side in the z-axis direction, and is also connected to the end of the second hole 222 on the positive side in the z-axis direction.
- An end of the third hole 223 on the positive side in the x-axis direction is bent toward the negative side in the z-axis direction and opened on the surface of the front body 24 on the negative side in the z-axis direction, and is also connected to the end of the first inner diameter gradually-reducing portion 210 a on the positive side in the z-axis direction.
- An inner diameter of the end of the first inner diameter gradually-reducing portion 210 a on the positive side in the z-axis direction is approximately equal to an inner diameter of the third hole 223 .
- the fourth hole 224 connects the end of the valve containing hole 227 on the positive side in the x-axis direction and the small diameter portion 51 of the venturi portion 50 .
- the pump housing 2 does not include the venturi forming block 21 , and the inner diameter gradually-reducing portion 210 and the venturi portion 50 are directly formed inside the pump housing 2 (the rear body 22 ). Therefore, the present embodiment can reduce the number of components.
- the venturi portion 50 should have a long dimension (a large space in the longitudinal direction) compared to the orifice.
- the pump housing 2 has a dimension of the driving shaft 40 in the rotational axis direction that is enough to contain the pump element 4 therein from the beginning.
- the venturi portion 50 is disposed so as to be located on the radially outer side with respect to the pump element containing portion (the containing recessed portion 220 ) and overlap the pump element containing portion (the containing recessed portion 220 ) in the direction of the rotational axis (the central axis O) of the driving shaft 40 .
- the venturi portion 50 is disposed so as to utilize the originally existing space extending in the direction of the rotational axis of the driving shaft 40 in this manner, by which the present embodiment can prevent or cut down the increase in the size of the outer shape of the pump element 1 (in the direction of the rotational axis of the driving shaft 40 ). Further, the venturi portion 50 is disposed in such a manner that the longitudinal direction of the venturi portion 50 and the direction of the rotational axis (the central axis O) of the driving shaft 40 extend generally in parallel with each other. Therefore, the present embodiment can prevent or cut down the increase in the dimension of the pump apparatus 1 in the radial direction of the rotational axis of the driving shaft 40 .
- the functions and effects due to the above-described layout can also be acquired even when the venturi portion 50 is formed in the venturi forming block 21 .
- the pump apparatus 1 is different from the first embodiment in terms of the housing where the venturi portion 50 and the control valve 8 are set up.
- the fifth embodiment will be described below focusing on only differences from the first embodiment.
- a transmission housing 10 a is a housing of the CVT unit, and is a separate member from the pump housing 2 .
- the pump housing 2 may be disposed integrally with the transmission housing 10 a, or may be spaced apart from the transmission housing 10 a. While the pump element 4 is provided in the pump housing 2 , the venturi portion 50 and the control valve 8 are provided in the transmission housing (for example, a housing of the control valve) 10 a as indicated by a broken line illustrated in FIG. 1 .
- the venturi portion 50 or the control valve 8 is not provided on the pump housing 2 side but is provided on the transmission housing 10 a side, by which the present embodiment can reduce the size of the unit including the pump element 4 and improve layout flexibility thereof.
- the control valve 8 is provided on the transmission housing 10 a side, the hydraulic fluid supplied from the pump element 4 (the pump housing 2 ) to the transmission housing 10 a is a flow amount before the hydraulic fluid is controlled by the control valve 8 .
- the control valve 8 controls the flow amount of the hydraulic fluid to be supplied from the pump element 4 to the CVT 10 .
- the above-described “flow amount of the hydraulic fluid to be supplied from the pump element 4 to the CVT 10 ” means a flow amount to be actually supplied to the CVT 10 existing inside the transmission housing 10 a.
- the venturi portion 50 may be provided in the transmission housing 10 a, and the pump element 4 and the control valve 8 may be provided in the pump housing 2 . Further, the venturi portion 50 and the control valve 8 may be provided in a housing other than the transmission housing 10 a.
- the pump element according to a sixth embodiment is a variable displacement pump in which the pump capacity is variably controlled.
- the sixth embodiment will be described below focusing on only configurations different from the first embodiment. Configurations shared with the first embodiment will be identified by the same reference numerals as the first embodiment, and descriptions thereof will be omitted.
- FIG. 16 is a similar view to FIG. 2 that schematically illustrates a configuration of the pump apparatus 1 .
- FIG. 17 illustrates a partial cross section acquired by cutting the pump housing 2 along the plane including the central axis O. The z axis is set to a horizontal direction in FIG. 17 , and a positive side thereof is set to a right side in FIG. 17 .
- the containing recessed portion 220 , an intake pressure chamber 220 a, the discharge pressure chamber 226 , the valve containing hole 227 , the venturi forming block containing hole (not illustrated), a bearing holding hole 229 , and the plurality of passages 3 and the like are formed in the rear body 22 .
- the plurality of passages 3 and the like include the intake passage 3 , the discharge passage 5 , the high pressure passage 6 , the intermediate pressure passage 7 , a first control passage 60 , a second control passage 70 , and the return passage 9 .
- the intake pressure chamber 220 a and the discharge pressure chamber 226 are opened to the bottom portion of the containing recessed portion 220 .
- a bush 401 as a bearing is mounted on an inner periphery of the bearing holding hole 229 .
- the end of the valve containing hole 227 on the negative side in the x-axis direction is opened on the outer surface of the rear body 22 .
- a solenoid 80 is fitted in this opening via a seal member 253 .
- a rod 800 protrudes from the solenoid 80 toward the positive side in the x-axis direction.
- a shaft containing hole 234 is provided at the side plate 23 .
- the intake port 230 , the discharge port 231 , an intake-side backpressure port 232 , and a discharge-side backpressure port 233 are provided at the surface of the side plate 23 on the one side in the axial direction.
- the intake port 230 and the discharge port 231 are grooves extending in the circumferential direction in a generally circular-arc manner, and are provided at positions opposite of the shaft containing hole 234 from each other.
- the intake-side backpressure port 232 is a groove extending in the circumferential direction in a generally circular-arc manner on one side closer to the shaft containing hole 234 (the radially inner side) with respect to the intake port 230 , and is provided in a range overlapping the intake port 230 in the circumferential direction.
- the discharge-side backpressure port 233 is a groove extending in the circumferential direction in a generally circular-arc manner on the radially inner side with respect to the discharge port 231 , and is provided in a range overlapping the discharge port 231 in the circumferential direction.
- the intake port 230 and the intake-side backpressure port 232 are connected to the intake pressure chamber 220 a of the rear body 22 via a communication passage in the side plate 23 .
- the discharge port 231 and the discharge-side backpressure port 233 are connected to the discharge pressure chamber 226 via a communication passage in the side plate 23 .
- An annular seal groove is formed on the surface of the side plate 23 on the negative side in the z-axis direction so as to surround an outer edge of the side plate 23 .
- An annular seal member 250 is mounted in this seal groove.
- An annular seal groove is formed on the surface of the bottom portion of the containing recessed portion 220 on the positive side in the z-axis direction so as to surround an opening of the bearing holding hole 229 .
- An annular seal member 251 is mounted in this seal groove.
- An annular seal groove is formed on the surface of the bottom portion of the containing recessed portion 220 on the positive side in the z-axis direction so as to surround an outer periphery of an opening of the discharge pressure chamber 226 .
- An annular seal member 252 is mounted in this seal groove.
- the seal member 252 defines a high pressure region and a low pressure region on an inner peripheral side and an outer peripheral side of the seal member 252 , respectively.
- a bush 402 as a bearing is mounted on an inner periphery of a bearing holding hole 244 of the front body 24 .
- An intake port 240 and a discharge port 241 , and an intake-side backpressure port 242 and a discharge-side backpressure port 243 are formed on the end surface of the front body 24 on the negative side in the z-axis direction at positions generally corresponding in the z-axis direction to the individual ports 230 and 231 and the individual ports 232 and 233 formed at the side plate 23 and with similar shapes to them, respectively.
- the front body 24 is fixed by being fastened to the rear body 22 with use of a bolt 26 .
- An adapter ring 44 is mounted in the containing recessed portion 220 of the rear body 22 on the positive side of the side plate 23 in z-axis direction.
- the adapter ring 44 has an annular shape, and an outer periphery of the adapter ring 44 is fitted to the inner periphery of the containing recessed portion 220 .
- An inner peripheral surface of the adapter ring 44 has a generally cylindrical shape extending in the z-axis direction and is generally ecliptic as viewed from the z-axis direction.
- a first groove portion 441 , a second groove portion 442 , a first flat surface portion 443 , a second flat surface portion 444 , and a recessed portion 445 are provided on this inner peripheral surface.
- the first groove portion 441 has a semi-cylindrical shape extending in the z-axis direction, and is provided on the first flat surface portion 443 .
- the first and second control passages 60 and 70 are provided on both sides of the first groove portion 441 so as to radially penetrate through the adapter ring 44 .
- the second groove portion 442 is provided on an opposite side of a center (a central axis) of the adapter ring 44 from the first groove portion 441 , and extends in the z-axis direction.
- the second flat surface portion 444 is provided between the first and second groove portions 441 and 442 (a generally middle position therebetween) in a circumferential direction of the adapter ring 44 .
- the recessed portion 445 is provided on an opposite side of the center of the adapter ring 44 from the second flat surface portion 444 .
- the pump element 4 is contained in a space surrounded by an inner peripheral surface of the adapter ring 44 , the surface of the side plate 23 on the positive side in the z-axis direction, and the surface of the front body 24 on the negative side in the z-axis direction.
- the above-described space functions as the pump element containing portion.
- Eleven slits 410 are provided at the rotor 41 .
- the cam ring 43 is annularly formed, and the inner peripheral surface thereof has a generally cylindrical shape.
- a semi-cylindrical groove portion 433 extending in the z-axis direction is provided on an outer peripheral surface of the cam ring 43 .
- the cam ring 43 is provided in the pump element containing portion so as to surround the rotor 41 .
- the cam ring 43 forms the plurality of pump chambers 400 together with the rotor 41 and the vanes 42 .
- the side plate 23 and the front body 24 are disposed on the side surfaces of the cam ring 43 and the rotor 41 in the axial direction.
- the space between the inner peripheral surface of the cam ring 43 and the outer peripheral surface of the rotor 41 is sealingly closed on the both sides thereof in the axial direction by the side plate 23 and the front body 24 , while being divided into the eleven pump chambers 400 by the plurality of vanes 42 .
- the cam ring 43 is provided displaceably in the pump element containing portion.
- a pin 453 is installed by being fitted between the first groove portion 441 of the adapter ring 44 and the groove portion 433 of the cam ring 43 .
- the pin 453 is fixed to the pump housing 2 .
- the pin 453 prevents or reduces a rotation of the adapter ring 44 relative to the pump housing 2 and also prevents or reduces a rotation of the cam ring 43 relative to the adapter ring 44 .
- the cam ring 43 is contained on the inner peripheral side of the adapter ring 44 swingably relative to the pump housing 2 .
- the cam ring 43 is supported on the first flat surface portion 443 relative to the adapter ring 44 .
- the cam ring 43 swings with the first flat surface portion 443 serving as a supporting point thereof by being displaced while rolling on the first flat surface portion 443 .
- an amount by which a center (a central axis) of the inner peripheral surface of the cam ring 43 is offset from the center (the central axis O) of the rotor 41 (the driving shaft 40 ) will be referred to as an eccentric amount 5 .
- a seal member 46 is mounted in the second groove portion 442 of the adapter ring 44 .
- the first flat surface portion 443 of the adapter ring 44 contacts the outer peripheral surface of the cam ring 43 and the seal member 46 also contacts the outer peripheral surface of the cam ring 43 .
- the above-described space between the inner peripheral surface of the adapter ring 44 and the outer peripheral surface of the cam ring 43 is liquid-tightly divided into a pair of spaces by the first flat surface portion 443 (a portion thereof in abutment with the outer peripheral surface of the cam ring 43 ) and the seal member 46 .
- two fluid pressure chambers 61 and 71 are formed as the pair of spaces between the cam ring 43 and the pump element containing portion.
- an X axis and a Y axis are set to a long-axis direction and a short-axis direction of the generally ecliptic inner peripheral surface of the adapter ring 44 , respectively, as illustrated in FIG. 16 .
- a first fluid pressure chamber 61 is defined on the negative side in the X-axis direction that is one side where the eccentric amount ⁇ increases
- a second fluid pressure chamber 71 is defined on the positive side in the X-axis direction that is the other side where ⁇ reduces.
- One end of a spring 47 is set in the recessed portion 445 of the adapter ring 44 inside the second fluid pressure chamber 71 .
- the other end of the spring 47 is set on the outer peripheral side of the cam ring 43 .
- the spring 47 is mounted in a compressed state, and constantly biases the cam ring 43 relative to the adapter ring 44 toward the negative side in the X-axis direction (the one side where the first fluid pressure chamber 61 is located).
- the displacement of the cam ring 43 toward the negative side in the X-axis direction is regulated by abutment of the outer peripheral surface of the cam ring 43 with the second flat surface portion 444 of the adapter ring 44 inside the first fluid pressure chamber 61 .
- the rotor 41 rotates in a clockwise direction in FIG. 16 .
- a radial distance between the outer peripheral surface of the rotor 41 and the inner peripheral surface of the cam ring 43 increases as approaching the negative side in the X-axis direction from the positive side in the X-axis direction.
- the vane 42 projects from the slit 410 and retracts into the slit 410 according to this change in the distance, by which each of the pump chamber 400 is defined.
- the volume of the pump chamber 400 on the negative side in the X-axis direction becomes larger than the volume of the pump chamber 400 on the positive side in the X-axis direction. Due to this difference in the volume of the pump chamber 400 , the volume of the pump chamber 400 reduces as the rotor 41 rotates (as the pump chamber 400 travels toward the positive side in the X-axis direction) on the positive side in the Y-axis direction with respect to the central axis O, while increasing as the rotor 41 rotates (as the pump chamber 400 travels toward the negative side in the X-axis direction) on the negative side in the Y-axis direction with respect to the central axis O.
- the pump chamber 400 periodically expands and contracts while rotating in the clockwise direction around the central axis O.
- the intake port 230 is opened to the intake region where the volume of the pump chamber 400 increases according to the rotation of the driving shaft 40 .
- the discharge port 231 is opened to the discharge region where the volume of the pump chamber 400 reduces according to the rotation of the driving shaft 40 .
- the intake passage 3 connects the oil pan 100 and the intake pressure chamber 220 a to each other.
- the discharge passage 5 connects the discharge pressure chamber 226 and the CVT 10 to each other.
- the high pressure passage 6 branches off from the discharge passage 5 on the upstream side of the venturi portion 50 in the discharge passage 5 , and is connected to the positive side of the valve containing hole 227 in the x-axis direction.
- the intermediate pressure passage 7 branches off from the venturi portion 50 (the small diameter portion 51 ) in the discharge passage 5 and is connected to the negative side of the valve containing hole 227 in the x-axis direction.
- the first control passage 60 and the second control passage 70 connect the control valve 8 and the pump element 4 to each other.
- the first control passage 60 is connected to the positive side of the valve containing hole 227 in the x-axis direction with respect to the high pressure passage 6 , and is also connected to the first fluid pressure chamber 61 by penetrating through the adapter ring 44 .
- the second control passage 70 is connected to the negative side of the valve containing hole 227 in the x-axis direction with respect to the intermediate pressure passage 7 , and is also connected to the second fluid pressure chamber 71 by penetrating through the adapter ring 44 .
- the return passage 9 is connected to between the first control passage 60 and the second control passage 70 in the valve containing hole 227 .
- the high pressure passage 6 is opened to the high pressure chamber 86
- the intermediate pressure passage 7 is opened to the intermediate pressure chamber 88
- the return passage 9 is opened to the drain chamber 89 .
- the control valve 8 switches the flow passage of the hydraulic fluid between the first control passage 60 and the second control passage 70 .
- an opening portion of the first control passage 60 in the valve containing hole 227 is in communication with the drain chamber 89 while being out of communication with the high pressure chamber 86 due to the first land portion 8 .
- an opening portion of the second control passage 70 is in communication with the intermediate pressure chamber 88 while being out of communication with the drain chamber 89 due to the second land portion 82 .
- the hydraulic fluid in the intermediate pressure chamber 88 flows into the second fluid pressure chamber 71 .
- the high pressure is not supplied into the first fluid pressure chamber 61 and the intermediate pressure is supplied into the second fluid pressure chamber 71 , so that the cam ring 43 is displaced into an eccentric state. Therefore, the pump discharge flow amount increases according to the number of rotations.
- the opening portion of the first control passage 60 is in communication with the high pressure chamber 86 while being out of communication with the drain chamber 89 due to the first land portion 81 .
- the opening portion of the second control passage 70 is in communication with the drain chamber 89 while being out of communication with the intermediate pressure chamber 88 due to the second land portion 82 .
- the flow passage is switched, so that the hydraulic fluid in the high pressure chamber 86 starts to flow into the first fluid pressure chamber 61 via the first control passage 60 .
- the high pressure is supplied into the first fluid pressure chamber 61 , and the intermediate pressure is not supplied into the second fluid pressure chamber 71 . Therefore, the eccentric amount ⁇ of the cam ring 43 reduces and the pump capacity reduces, so that the pump discharge flow amount does not increase even when the number of rotations of the pump increases.
- the control valve 8 switches the flow passage in such a manner that the hydraulic fluid introduced via the high pressure passage 6 is introduced into the first fluid pressure chamber 61 based on the differential pressure ⁇ p between the upstream side and the small diameter portion 51 of the venturi portion 50 .
- the venturi portion 50 , the high pressure passage 6 , the intermediate pressure passage 7 , the control valve 8 , the first control passage 60 , the second control passage 70 , the first fluid pressure chamber 61 , and the second fluid pressure chamber 71 function as a controller that controls the discharge flow amount of the pump element 4 .
- the activation of the control valve 8 is controlled based on the differential pressure ⁇ p applied to the both sides of the control valve 8 in the axial direction according to the discharge flow amount of the pump element 4 , and is also controlled based on a thrust force applied from the solenoid 80 to the control valve 8 .
- a distal end of the rod 800 of the solenoid 80 is in abutment with the end surface of the control valve 8 on the negative side in the x-axis direction.
- the rod 800 is displaceable in the x-axis direction due to an electromagnetic force generated by the solenoid 80 .
- the control valve 8 is subjected to a force F 4 applied from the solenoid 80 toward the positive side in the x-axis direction via the rod 800 .
- the thrust force F 4 of the solenoid 80 is controlled based on an instruction from the CVT control unit.
- F 1 ⁇ F 2 the force corresponding to the differential pressure ⁇ p
- F 4 the force corresponding to the differential pressure ⁇ p
- F 3 the control valve 8 is displaced toward the positive side in the x-axis direction.
- the solenoid 80 deactivated the force competing against the initial set load F 3 of the spring 88 is only the force F 1 ⁇ F 2 due to the differential pressure ⁇ p.
- the differential pressure ⁇ p i.e., F 1 ⁇ F 2
- the differential pressure ⁇ p cannot be sufficiently secured until the discharge flow amount increases to some degree.
- the CVT control unit appropriately controls a line pressure of the CVT 10 according to running conditions such as the number of revolutions of the engine, an opening degree of an accelerator (an opening degree of a throttle valve), and a vehicle speed. According thereto, the CVT control unit supplies a current to the solenoid 80 based on the number of revolutions of the engine, the opening degree of the accelerator, and the like to control the magnetic attractive force (the thrust force F 4 ), thereby changing the discharge flow amount (the pump capacity) of the pump element 4 .
- the pump apparatus 1 may be configured to omit the solenoid 80 .
- the present embodiment can also acquire each of functions and effects regarding the venturi portion 50 similar to the first embodiment even for the variable displacement pump.
- the specific configuration of the present invention is not limited to the embodiments, and the present invention also includes a design modification and the like thereof made within a range that does not depart from the spirit of the present invention.
- the stepless transmission to which the pump apparatus supplies the hydraulic fluid is not limited to the CVT, and may be, for example, a toroidal-type transmission.
- the automatic transmission to which the pump apparatus supplies the hydraulic fluid is not limited to the stepless transmission, and may be a stepped transmission.
- the apparatus mounted on the vehicle to which the pump apparatus supplies the hydraulic fluid is not limited to the automatic transmission, and may be a power steering apparatus or the like.
- the configurations of the individual embodiments can also be arbitrarily combined to each other or one another.
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Abstract
The present invention provides a pump apparatus capable of preventing or reducing deterioration of efficiency of a pump. The pump apparatus includes a venturi portion provided on the way along a discharge passage. The venturi portion includes a small diameter portion having a smaller inner diameter than an inner diameter of the discharge passage from a discharge port to the venturi portion and an inner diameter gradually-increasing portion formed in such a manner that an inner diameter thereof gradually increases from the small diameter portion toward a downstream side of the discharge passage. The pump apparatus further includes a control valve configured to receive introduction of hydraulic fluid on an upstream side of the venturi portion and hydraulic fluid in the venturi portion. The control valve is configured to control a flow amount of hydraulic fluid to be supplied into an automatic transmission by switching a flow passage of the hydraulic fluid based on a differential pressure between a pressure on the upstream side of the venturi portion and a pressure in the venturi portion (50).
Description
- The present invention relates to a pump apparatus.
- Conventionally, there has been known a pump apparatus including a control valve. The control valve controls a flow amount of hydraulic fluid that the pump apparatus supplies to an apparatus. For example, a pump apparatus discussed in
PTL 1 generates a differential pressure according to the flow amount to be discharged. The control vale controls the above-described flow amount by switching a flow passage of the hydraulic fluid based on the above-described differential pressure. - PTL 1: Japanese Patent Application Public Disclosure No. 2010-14074
- However, the conventional pump apparatus uses an orifice for generating the differential pressure. Therefore, efficiency of the pump may be deteriorated. An object of the present invention is to provide a pump apparatus capable of preventing or reducing deterioration of the efficiency of the pump.,
- To achieve the above-described object, one embodiment of the present invention includes a venturi portion provided on the way along a discharge passage to generate a differential pressure and having an inner diameter gradually increasing from a small diameter portion toward a downstream side of the discharge passage.
- Therefore, the deterioration of the efficiency of the pump can be prevented or reduced.
-
FIG. 1 illustrates a configuration of a hydraulic system to which a pump apparatus according to a first embodiment is applied. -
FIG. 2 schematically illustrates a configuration of the pump apparatus according to the first embodiment. -
FIG. 3 illustrates a partial cross section acquired by cutting a pump housing according to the first embodiment along a plane perpendicular to a central axis of a diving shaft. -
FIG. 4 illustrates a cross section as viewed from a line A-A illustrated inFIG. 3 . -
FIG. 5 illustrates a venturi forming block according to the first embodiment as viewed from one side in an axial direction. - An upper diagram of
FIG. 6 schematically illustrates a discharge passage around a venturi portion according to the first embodiment. A lower diagram ofFIG. 6 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram. - An upper diagram of
FIG. 7 schematically illustrates a discharge passage around an orifice according to a comparative example. A lower diagram ofFIG. 7 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram. -
FIG. 8 is a graph indicating a relationship between a flow amount and a differential pressure according to the first embodiment. A solid line indicates the first embodiment, and an alternate long and short dash line indicates the comparative example. -
FIG. 9 illustrates a relationship between a narrower angle and a pressure loss rate according to the first embodiment. - An upper diagram of
FIG. 10 schematically illustrates a discharge passage in which a large diameter portion is provided upstream of the venturi portion according to the first embodiment. A lower diagram ofFIG. 10 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram. - An upper diagram of
FIG. 11 schematically illustrates a discharge passage including a stepped portion (a rear portion) on a downstream side of an inner diameter gradually-increasing portion according to the first embodiment. A lower diagram ofFIG. 11 illustrates a change in a pressure that is associated with each portion illustrated in the upper diagram. -
FIG. 12 illustrates a relationship between L/L0, which is a ratio of L to L0 illustrated inFIG. 11 , and the pressure loss rate. -
FIG. 13 illustrates a cross section acquired by cutting a venturi forming block according to a second embodiment along a plane passing through a central axis of the venturi portion. -
FIG. 14 illustrates a pump housing according to a fourth embodiment as viewed from a direction in which the central axis of the driving shaft extends. -
FIG. 15 illustrates a cross section as viewed from a line B-B illustrated inFIG. 14 . -
FIG. 16 schematically illustrates a configuration of a pump apparatus according to a sixth embodiment. -
FIG. 17 illustrates a partial cross section acquired by cutting a pump housing according to the sixth embodiment along a plane including the central axis of the driving shaft. - In the following description, embodiments for implementing a pump apparatus according to the present invention will be described based on exemplary embodiments illustrated in the drawings.
- First, a configuration will be described.
FIG. 1 illustrates a configuration of a hydraulic system to which apump apparatus 1 is applied. Thepump apparatus 1 is mounted on a vehicle of an automobile. Thepump apparatus 1 is a hydraulic fluid supply source that supplies hydraulic fluid to another apparatus mounted on the vehicle (an apparatus mounted on a vehicle). The apparatus mounted on the vehicle to which thepump apparatus 1 supplies the hydraulic fluid is an automatic transmission. The automatic transmission is a stepless transmission, in particular, a belt-type continuously variable transmission (hereinafter referred to as a CVT) 10. The hydraulic fluid is ATF (automatic transmission fluid). Thepump apparatus 1 is driven by an internal-combustion engine as a prime mover thereof, and introduces and discharges the hydraulic fluid from and into anoil pan 100. For example, an oil pan of the CVT 10 can be used as theoil pan 100. Various types of valves controlled by a CVT control unit are provided in a control valve of theCVT 10. The hydraulic fluid discharged from thepump apparatus 1 is supplied to each unit (a primary pulley, a secondary pulley, a forward clutch, a reverse brake, a torque converter, a lubricant/cooling system, and the like) of the CVT 10 via the control valve. - The
pump apparatus 1 includes apump housing 2, apump element 4, aventuri portion 50, and acontrol valve 8. Thepump housing 2 contains thepump element 4, thecontrol valve 8, and theventuri portion 50 therein. Anintake passage 3, adischarge passage 5, ahigh pressure passage 6, anintermediate pressure passage 7, and areturn passage 9 are provided in thepump housing 2 as passages through which the hydraulic fluid flows. Theintake passage 3 connects theoil pan 100 and thepump element 4 to each other. Thedischarge passage 5 connects thepump element 4 and the CVT 10 to each other. Theventuri portion 50 is a constriction portion provided on the way along thedischarge passage 5. Thehigh pressure passage 6 connects one side of thedischarge passage 5 that is closer to thepump element 4 than theventuri portion 50 is (hereinafter referred to as an upstream side) and thecontrol valve 8 to each other. Theintermediate pressure passage 7 connects theventuri portion 50 and thecontrol valve 8 to each other. Thereturn passage 9 connects thecontrol valve 8 and the intake passage 3 (the oil pan 100) to each other. Adriving shaft 40 is pivotally supported in thepump housing 2. Thedriving shaft 40 is driven by a crank shaft of the internal-combustion engine. Thepump element 4 is rotationally driven by thedriving shaft 40. Thepump element 4 introduces the hydraulic fluid therein from theoil pan 100 via theintake passage 3. Thepump element 4 discharges the hydraulic fluid to thedischarge passage 5, and supplies the hydraulic fluid to theCVT 10 via thedischarge passage 5. A relatively high pressure (hereinafter referred to as a high pressure) on the upstream side of theventuri portion 50 is fed into thecontrol valve 8 via thehigh pressure passage 6. Further, a relatively low pressure (a pressure around an intermediate level, hereinafter referred to as an intermediate pressure) in theventuri portion 50 is fed into thecontrol valve 8 via theintermediate pressure passage 7. Thecontrol valve 8 switches a flow passage of the hydraulic fluid based on a difference (a differential pressure) between the pressure on the upstream side of theventuri portion 50 and the pressure in theventuri portion 50. By this switching, thecontrol valve 8 controls a flow amount of the hydraulic fluid that thepump element 4 supplies to theCVT 10. -
FIG. 2 schematically illustrates a configuration of thepump apparatus 1.FIG. 2 illustrates a cross section acquired by cutting thepump element 4 in a state extracted from thepump housing 2 along a plane perpendicular to a center axis (a rotational axis) O of the drivingshaft 40.FIG. 2 illustrates a partial cross section acquired by cutting thecontrol valve 8 along a plane passing through a central axis thereof.FIG. 2 schematically illustrates each of thepassages 3 and the like. A direction in which the hydraulic fluid flows is indicated by an arrowed alternate long and short dash line.FIG. 3 illustrates a partial cross section acquired by cutting thepump housing 2 along the plane perpendicular to the central axis O.FIG. 4 illustrates a cross section as viewed from a line A-A illustrated inFIG. 3 . Hereinafter, an orthogonal coordinate system is set for convenience of the description. An x axis is set to a horizontal direction inFIG. 3 , and a positive side thereof is set to a right side inFIG. 3 . A y axis is set to a vertical direction in the sheet ofFIG. 3 , and a positive side thereof is set to an upper side. A z axis is set to a direction perpendicular to the sheet ofFIG. 3 , and a positive side thereof is set to a front side of the sheet. The driving shaft 40 (the central axis O) extends in the z-axis direction. Thepump housing 2 includes a pump housingmain body 20 and aventuri forming block 21. The pump housingmain body 20 is made from a metallic material. Anintake port 230 and adischarge port 231 are formed at the pump housingmain body 20, besides each of the above-describedpassages 3 and the like. Theventuri forming block 21 is made from a resin material. Theventuri forming block 21 is a member separate from the pump housingmain body 20. - The pump housing
main body 20 includes arear body 22, aside plate 23, and a front body. A containing recessedportion 220, afirst hole 221, asecond hole 222, athird hole 223, afourth hole 224, afifth hole 225, adischarge pressure chamber 226, avalve containing hole 227, a venturi formingblock containing hole 228, and a bearing holding hole are formed at therear body 22. The containing recessedportion 220 has a bottomed cylindrical shape. The containing recessedportion 220 extends in the z-axis direction and is opened on a positive side of therear body 22 in the z-axis direction. Semi-cylindrical first and second groove portions (not illustrated) are formed on an inner peripheral surface of the containing recessedportion 220 so as to extend in the z-axis direction. The second groove portion is provided on an opposite side of a central axis of the containing recessedportion 220 from the first groove portion. The bearing holding hole (not illustrated) has a bottomed cylindrical shape. The bearing holding hole extends in the z-axis direction and is opened to a bottom portion of the containing recessedportion 220 on the negative side in the z-axis direction. A bearing is mounted on an inner periphery of the bearing holding hole. An end of the drivingshaft 40 on the negative side in the z-axis direction is inserted on an inner peripheral side of the bearing and is rotatably mounted. Thedischarge pressure chamber 226 is a bottomed recessed portion provided at the above-described bottom portion of the containing recessedportion 220, and is opened to the above-described bottom portion. - The
first hole 221 extends in the y-axis direction on a negative side of therear body 22 in the x-axis direction and a negative side of therear body 22 in the z-axis direction. An opening of thefirst hole 22 on a negative side of therear body 22 in the y-axis direction is sealingly closed by aplug member 221 a. Thefirst hole 221 is formed so as to partially overlap thedischarge pressure chamber 226 as viewed from the y-axis direction and the z-axis direction, and is connected to thedischarge pressure chamber 226. Thevalve containing hole 227 has a generally cylindrical shape, and extends in the x-axis direction on a positive side of therear body 22 in the y-axis direction and a negative side of therear body 22 in the z-axis direction. In other words, a longitudinal direction of the valve containing hole 227 (the x-axis direction) extends perpendicularly to a direction along the central axis O (the z-axis direction). An end of thevalve containing hole 227 on the positive side in the x-axis direction is opened on an outer surface of therear body 22. This opening is sealingly closed by aplug member 227 a. An end of thevalve containing hole 227 on the negative side in the x-axis direction is connected to an end of thefirst hole 221 on the positive side in the y-axis direction. One end of thefifth hole 225 is opened on a portion of thevalve containing hole 227 that is closer to the negative side in the x-axis direction. The other end of thefifth hole 225 is opened on the outer surface of therear body 22. - The venturi forming
block containing hole 228 has a generally cylindrical shape, and extends in the x-axis direction on the negative side of therear body 22 in the z-axis direction. In other words, a longitudinal direction of the venturi forming block containing hole 228 (the x-axis direction) extends generally in parallel with the longitudinal direction of thevalve containing hole 227, and also extends perpendicularly to the direction along the central axis O (the z-axis direction). A negative side of the venturi formingblock containing hole 228 in the x-axis direction is formed so as to intersect thefirst hole 221 and is connected to thefirst hole 221. Further, the negative side of the venturi formingblock containing hole 228 in the x-axis direction is formed so as to partially overlap thedischarge pressure chamber 226 as viewed from the y-axis direction and the z-axis direction, and is connected to thedischarge pressure chamber 226. An end of the venturi formingblock containing hole 228 on the negative side in the x-axis direction is opened on the outer surface of therear body 22. This opening is sealingly closed by aplug member 228 a. Thesecond hole 222 is provided on a generally same central axis as the venturi formingblock containing hole 228, and extends in the x-axis direction on a positive side of therear body 22 in the x-axis direction and the negative side of therear body 22 in the z-axis direction. An end of thesecond hole 222 on the negative side in the x-axis direction is connected to an end of the venturi formingblock containing hole 228 on the positive side in the x-axis direction. An inner diameter of thesecond hole 222 is smaller than an inner diameter of the venturi formingblock containing hole 228. Thethird hole 223 extends in the z-axis direction on the positive side of therear body 22 in the x-axis direction and the negative side of therear body 22 in the z-axis direction. An end of thethird hole 223 on the positive side in the z-axis direction is connected to an end of thesecond hole 222 on the positive side in the x-axis direction. An end of thethird hole 223 on the negative side in the z-axis direction is opened on the outer surface of therear body 22. Thefourth hole 224 connects a positive side of thevalve containing hole 227 in the x-axis direction and a positive side of the venturi formingblock containing hole 228 in the x-axis direction to each other. - The
side plate 23 has a disk-like shape. A shaft containing hole (not illustrated) is provided at theside plate 23. The shaft containing hole penetrates through a central portion of theside plate 23. A pair ofintake ports discharge ports side plate 23 on one side in an axial direction. The pair ofintake ports discharge ports intake ports 230 and thedischarge ports 231 are arranged alternately in the circumferential direction. A communication passage (not illustrated) is provided at theside plate 23. The communication passage axially penetrates though theside plate 23 to establish communication between both side surfaces thereof. A first communication passage is opened to theintake port 230. A second communication passage is opened to thedischarge port 231. Theside plate 23 is installed in the containing recessedportion 220 of therear body 22. A surface of theside plate 23 on the above-described one side faces an opening side of the containing recessed portion 220 (the positive side in the z-axis direction). A surface of theside plate 23 on the other side faces the bottom portion of the containing recessedportion 220. The shaft containing hole of theside plate 23 faces the bearing holding hole of therear body 22. The first communication passage of theside plate 23 faces the bearing holding hole of therear body 22. The first communication passage of theside plate 23 is connected to theintake passage 3 of therear body 22. Each of theintake ports 230 is connected to theintake passage 3 via the first communication passage. The second communication passage of theside plate 23 is connected to thedischarge pressure chamber 226 of therear body 22. Each of thedischarge ports 231 is connected to thedischarge pressure chamber 226 via the second communication passage. - A front body (not illustrated) is a pump cover. The front body is fixed to the positive side of the
rear body 22 in the z-axis direction so as to sealingly close the containing recessedportion 220. A bearing holding hole is provided at thefront body 24. The bearing holding hole extends in the z-axis direction. A bearing is mounted on an inner periphery of the bearing holding hole. An end of the drivingshaft 40 on the positive side in the z-axis direction is inserted on the inner peripheral side of the bearing, and is rotatably mounted. - The
venturi forming block 21 has a generally cylindrical shape. A diameter (an outer diameter) of an outer peripheral surface of theventuri forming block 21 is approximately equal to a diameter (an inner diameter) of an inner peripheral surface of the venturi formingblock containing hole 228. Theventuri portion 50 is formed at theventuri forming block 21. Theventuri portion 50 is a constriction portion formed at theventuri forming block 21 by molding. Theventuri forming block 21 is joined to the pump housingmain body 20 after theventuri portion 50 is formed.FIGS. 3 and 4 illustrate the cross section acquired by cutting theventuri forming block 21 along the plane passing through the axis line (the central axis) along a longitudinal direction of theventuri portion 50.FIG. 5 illustrates theventuri forming block 21 as viewed from a direction in which the central axis of theventuri portion 50 extends (from the negative side in the x-axis direction). Hereinafter, the direction in which the central axis of theventuri portion 50 extends will be referred to as an axial direction, and a direction around the central axis will be referred to as a circumferential direction. Theventuri forming block 21 includes an inner diameter gradually-reducingportion 210, theventuri portion 50, acommunication hole 213, afirst communication groove 214, and asecond communication groove 215. Theventuri portion 50 includes asmall diameter portion 51 and an inner diameter gradually-increasingportion 52. - The inner diameter gradually-reducing
portion 210 is provided so as to extend in the axial direction toward an inner peripheral side of theventuri forming block 21, and is opened on an end surface of theventuri forming block 21 on one side in the axial direction. The inner diameter gradually-reducingportion 210 is a taper portion tapering from the one side in the axial direction toward the other side in the axial direction (a downstream side in the discharge passage 5), and is formed in such a manner that an inner diameter thereof gradually reduces toward the other side in the axial direction. An inner diameter of an end of the inner diameter gradually-reducingportion 210 on the one side in the axial direction is smaller than an inner diameter of the venturi formingblock containing hole 228. Thesmall diameter portion 51 is provided on the inner peripheral side of theventuri forming block 21, and extends in the axial direction. An end of thesmall diameter portion 51 on the one side in the axial direction is connected to an end of the inner diameter gradually-reducingportion 210 on the other side in the axial direction. An inner diameter of thesmall diameter portion 51 is approximately equal to an inner diameter of an end of the inner diameter gradually-reducingportion 210 on the other side in the axial direction, and is kept constant in the axial direction. - The inner diameter gradually-increasing
portion 52 is provided so as to extend in the axial direction on the inner peripheral side of theventuri forming block 21. An end of the inner diameter gradually-increasingportion 52 on the one side in the axial direction is connected to an end of thesmall diameter portion 51 on the other side in the axial direction, and an end of the inner diameter gradually-increasingportion 52 on the other side in the axial direction is opened on an end surface of theventuri forming block 21 on the other side in the axial direction. The inner diameter gradually-increasingportion 52 is a taper portion tapering from the other side in the axial direction toward the one side in the axial direction (the upstream side of the discharge passage 5), and is formed in such a manner that an inner diameter thereof gradually increases from the one side in the axial direction toward the other side in the axial direction (the downstream side of the discharge passage 5). An inner diameter of the end of the inner diameter gradually-increasingportion 52 on the other side in the axial direction is slightly smaller than the inner diameter of thesecond hole 222. Theventuri forming block 21 is formed in such a manner that a narrower angle e sandwiched between inner walls of the inner diameter-gradually increasing portion 52 (one of angles sandwiched between the inner walls as viewed from a direction perpendicular to the central axis of theventuri portion 50 that is equal to or smaller than 180 degree) is 60 degrees or smaller, in particular, approximately 15 degrees. - The
communication hole 213 is a radial hole formed inside theventuri forming block 21 and extending in a radial direction of theventuri forming block 21. A plurality of (four) communication holes 213 are provided, and are arranged at approximately equal intervals to one another in the circumferential direction. Each of the communication holes 213 is provided at a position overlapping thesmall diameter portion 51 in the axial direction. A radially inner end of each of the communication holes 213 is opened to thesmall diameter portion 51. Thefirst communication groove 214 is a circumferential groove formed on an outer peripheral surface of theventuri forming block 21 and extending in the circumferential direction. Thefirst communication groove 214 is provided at a position overlapping thesmall diameter portion 51 and thecommunication hole 213 in the axial direction. A radially outer end of each of the communication holes 213 is opened to the first communication groove 214 (a bottom portion thereof). Thesecond communication groove 215 is an axial groove formed on the outer peripheral surface of theventuri forming block 21 and extending in the axial direction. An end of thesecond communication groove 215 on the one side in the axial direction is connected to thefirst communication groove 214. An end of thesecond communication groove 215 on the other side in the axial direction is positioned close to the end surface of theventuri forming block 21 on the other side in the axial direction. - The
venturi forming block 21 is joined to the pump housing main body 20 (the venturi formingblock containing hole 228 of the rear body 22) as illustrated inFIGS. 3 and 4 after theventuri portion 50 is formed. The central axis of the venturi forming block 21 (the venturi portion 50) extends in the x-axis direction. The above-described one side of theventuri forming block 21 in the axial direction corresponds to the negative side in the x-axis direction, and the above-described other side of theventuri forming block 21 in the axial direction corresponds to the positive side in the x-axis direction. The end surface of theventuri forming block 21 on the other side in the axial direction (on which the inner diameter gradually-increasingportion 52 is opened) is in abutment with the end surface of the venturi formingblock containing hole 228 on the positive side in the x-axis direction (on which thesecond hole 222 is opened). The end of thesecond communication groove 215 in theventuri forming block 21 on the above-described other side in the axial direction is connected to an opening of thefourth hole 224 in the venturi formingblock containing hole 228. A third communication groove connected to the end of thesecond communication groove 215 on the other side in the axial direction and also extending in the circumferential direction may be provided at a position in the axial direction that radially faces the opening of thefourth hole 224 on the outer peripheral surface of theventuri forming block 21. In this case, the end of thesecond communication groove 215 on the other side in the axial direction and the opening of thefourth hole 224 are connected to each other via the third communication groove, which eliminates a necessity of adjusting a position of theventuri forming block 21 in a rotational direction around the central axis of the venturi formingblock containing hole 228. - The
pump element 4 is contained in a space surrounded by the inner periphery of the containing recessedportion 220 in therear body 22, the surface of theside plate 23 on the positive side in the z-axis direction, and the surface of the front body on the negative side in the z-axis direction. In other words, the above-described space functions as a pump element containing portion. The drivingshaft 40 is mounted in the above-described space, and thepump element 4 forms a plurality ofpump chambers 400 around the drivingshaft 40. As illustrated inFIG. 2 , thepump element 4 is a vane pump-type pump, and includes a set of arotor 41 andvanes 42. Therotor 41 is provided in the pump element containing portion, and is coupled with the drivingshaft 40 by serration coupling. Therotor 41 is rotationally driven by the drivingshaft 40, and rotates according to a rotation of the drivingshaft 40. A plurality of (ten) slits 410 (radially extending grooves) is each radially provided at therotor 41. Theslits 410 are each opened on an outer peripheral surface of therotor 41. The plurality ofslits 410 are provided at approximately equal intervals in a circumferential direction of therotor 41. Thevane 42 is set in each of theslits 410. Thevane 42 is a generally rectangular plate member (a vane). Thevane 42 is provided so as to be able to project from theslit 410 and retract into the slit 410 (provided in a projectable and retractable manner). - A
cam ring 43 has an annular shape. An outer periphery of thecam ring 43 is fitted in the inner periphery of the containing recessedportion 220. A center (a central axis) of thecam ring 43 approximately coincides with the central axis O. An inner peripheral surface of thecam ring 43 has a cylindrical shape extending in the z-axis direction, and is generally ecliptic as viewed from the z-axis direction. Semi-cylindrical first andsecond groove portions cam ring 43. Thesecond groove portion 432 is provided on an opposite side of the central axis O of thecam ring 43 from thefirst groove portion 431. Afirst pin 451 is mounted by being fitted between the above-described first groove portion of the containing recessedportion 220 and thefirst groove portion 431 of thecam ring 43. Asecond pin 452 is mounted by being fitted between the above-described second groove portion of the containing recessedportion 220 and thesecond groove portion 432 of thecam ring 43. Each of thepins main body 20. Thepints cam ring 43 relative to thepump housing 2. Thecam ring 43 is disposed around therotor 41 in the pump element containing portion. Thecam ring 43 forms the plurality ofpump chambers 400 together with therotor 41 and thevanes 42. In other words, theside plate 23 and thefront body 24 are disposed on side surfaces of thecam ring 43 and therotor 41 in the axial direction. A space between an inner peripheral surface of thecam ring 43 and an outer peripheral surface of therotor 41 is sealingly closed by theside plate 23 and thefront body 24 on the both sides thereof in the axial direction, while being divided into the plurality of (ten) pump chambers (volume chambers) 400 by the plurality ofvanes 42. - For convenience of the description, an X axis and a Y axis are set to a long-axis direction and a short-axis direction of the generally ecliptic inner peripheral surface of the
cam ring 43, respectively, as illustrated inFIG. 2 . Therotor 41 rotates in a counterclockwise direction inFIG. 2 . A radial distance between the outer peripheral surface of therotor 41 and the inner peripheral surface of the cam ring 43 (a radial dimension of the pump chamber 400) increases as approaching the negative side in the X-axis direction from the central axis O of thecam ring 43, or approaching the positive side in the X-axis direction from the central axis O. Thevane 42 projects from theslit 410 according to this change in the distance, by which each of thepump chambers 400 is defined. A volume of thepump chamber 400 increases as approaching the negative side in the X-axis direction from the central axis O or approaching the positive side in the X-axis direction from the central axis O. Due to this difference in the volume of thepump chamber 400, the volume of thepump chamber 400 reduces on the positive side in the X-axis direction with respect to the central axis O while increasing on the negative side in the X-axis direction with respect to the central axis O, as therotor 41 rotates (as thepump chamber 400 travels toward the negative side in the x-axis direction) on the positive side in the Y-axis direction with respect to the central axis O. The volume of thepump chamber 400 reduces on the negative side in the X-axis direction with respect to the central axis O while increasing on the positive side in the X-axis direction with respect to the central axis O, as therotor 41 rotates (thepump chamber 400 travel toward the positive side in the X-axis direction) on the negative side in the Y-axis direction with respect to the central axis O. - In this manner, the
pump chamber 400 periodically expands and contracts while rotating in the counterclockwise direction around the central axis O. Theintake port 230 is opened to a region on the negative side in the X-axis direction and the positive side in the Y-axis direction, and a region on the positive side in the X-axis direction and the negative side in the Y-axis direction. In other words, theintake port 230 is opened to an intake region where the volume of thepump chamber 400 increases according to the rotation of the driving shaft 40 (i.e., an intake region where thepump chamber 400 increasing in volume according to the rotation of the drivingshaft 40 among the plurality ofpump chambers 400 is located). Thedischarge port 231 is opened to a region on the positive side in the X-axis direction and the positive side in the Y-axis direction, and a region on the negative side in the X-axis direction and the negative side in the Y-axis direction. In other words, thedischarge port 231 is opened to a discharge region where the volume of thepump chamber 400 reduces according to the rotation of the driving shaft 40 (i.e., a discharge region where thepump chamber 400 reducing in volume according to the rotation of the drivingshaft 40 among the plurality ofpump chambers 400 is located). Thepump chamber 400 introduces the hydraulic fluid therein from theintake port 230 in the intake region, and discharges the (above-described introduced) hydraulic fluid into thedischarge port 231 in the discharge region. The intake and the discharge are each carried out twice per rotation of the drivingshaft 40 in correspondence with the pair ofintake ports discharge ports discharge ports 231 are collected into one portion. Thecam ring 43 is provided immovably in the pump element containing portion. In other words, thepump element 4 is a fixed displacement pump that discharges a constant amount as a discharge amount per rotation of the driving shaft 40 (hereinafter referred to as a pump capacity). Thepump element 4 may be a set of trochoidal pump-type inner and outer rotors or may be another type of pump. - The
control valve 8 is a spool valve body and is contained in thevalve containing hole 227. Thecontrol valve 8 is displaceable (capable of performing a stroke) in the x-axis direction in thevalve containing hole 227. Thecontrol valve 8 includes afirst land portion 81, asecond land portion 82, aconnection portion 83, aspacer portion 84, and a recessedportion 85. Each of theland portions land portions valve containing hole 227. In thecontrol valve 8, thefirst land portion 81 is provided on the negative side in the x-axis direction and thesecond land portion 82 is provided at an end on the positive side in the x-axis direction. Acircumferential groove 810 extending in a direction around the central axis of the control valve 8 (hereinafter referred to as a circumferential direction) is provided on an outer peripheral surface of thefirst land portion 81. A plurality ofcircumferential grooves 820 extending in the circumferential direction is provided on an outer peripheral surface of thesecond land portion 82. Theconnection portion 83 has a cylindrical shape sandwiched between both theland portions connection portion 83 is smaller than each of theland portions spacer portion 84 has a rod shape extending from thefirst land portion 81 toward the negative side in the x-axis direction. The recessedportion 85 has a bottomed cylindrical shape and extends in the x-axis direction inside thesecond land portion 82. The recessedportion 85 is opened on an end surface of thesecond land portion 82 on the positive side in the x-axis direction. - A
high pressure chamber 86 is defined inside thevalve containing hole 227 by being surrounded by an end surface of thefirst land portion 81 on the negative side in the x-axis direction and the inner peripheral surface of thevalve containing hole 227. Anintermediate pressure chamber 88 is defined by being surrounded by an end surface of thesecond land portion 82 on the positive side in the x-axis direction, the inner peripheral surface of thevalve containing hole 227, and an end surface of theplug member 227 a on the negative side in the x-axis direction. Adrain chamber 89 is defined on an outer periphery of theconnection portion 83 between thefirst land portion 81 and thesecond land portion 82. Aspring 88 is mounted in theintermediate pressure chamber 88. Thespring 88 is a coil spring. An end of thespring 88 on the positive side in the x-axis direction is held by theplug member 227 a. A negative side of thespring 88 in the x-axis direction is held inside the recessedportion 85 of thecontrol valve 8. Thespring 88 is mounted in a compressed state. Thespring 88 is a return spring constantly biasing thecontrol valve 8 toward the negative side in the x-axis direction. A displacement of thecontrol valve 8 in thevalve containing hole 227 toward the negative side in the x-axis direction is regulated by abutment of an end of thespacer portion 84 on the negative side in the x-axis direction with an end surface of thevalve containing hole 227 on the negative side in the x-axis direction. Thefirst hole 221 is opened to thehigh pressure chamber 86 and thefourth hole 224 is opened to theintermediate pressure chamber 88, regardless of the displacement of thecontrol valve 8 in thevalve containing hole 227. - Next, a configuration of the plurality of
passages 3 and the like will be described. Each of thedischarge ports 231 of theside plate 23 is in communication with thefirst hole 221 or the venturi formingblock containing hole 228 via thedischarge pressure chamber 226 of therear body 22. A portion where thedischarge pressure chamber 226 and thefirst hole 221 or the venturi formingblock containing hole 228 are connected to each other, a negative side of the venturi formingblock containing hole 228 in the x-axis direction with respect to the venturi forming block 21 (the inner diameter gradually-reducing portion 210), and the inner diameter gradually-reducingportion 210 function as thedischarge passage 5 from the discharge port 231 (the discharge pressure chamber 226) to the venturi portion 50 (thesmall diameter portion 51 and the inner diameter gradually-increasing portion 52), i.e., thedischarge passage 5 on the upstream side of theventuri portion 50. Thesmall diameter portion 51 is formed in such a manner that the inner diameter thereof is smaller than an inner diameter of the above-describeddischarge passage 5. The inner diameter gradually-increasingportion 52 of theventuri portion 50 is in communication with outside therear body 22 via thesecond hole 222 and thethird hole 223. Thesecond hole 222 and thethird hole 223 function as thedischarge passage 5 extending from theventuri portion 50 toward theCVT 10, i.e., thedischarge passage 5 on the downstream side of theventuri portion 50. An inner diameter of the above-describeddischarge passage 5 is larger than an inner diameter of an end of the inner diameter gradually-increasingportion 52 on the positive side in the x-axis direction. A portion between portions of thefirst hole 221 that are connected to (intersects) the venturi formingblock containing hole 228 and thevalve containing hole 227, respectively, functions as thehigh pressure passage 6 branching off from thedischarge passage 5 on the upstream side of theventuri portion 50 and is connected to thehigh pressure chamber 86 of thecontrol valve 8. Thecommunication hole 213, thefirst communication groove 214, and thesecond communication groove 215 of theventuri forming block 21, and thefourth hole 224 of therear body 22 function as the intermediate pressure passage 7 (a venturi portion pressure introduction passage) branching off from the venturi portion 50 (the small diameter portion 51) in thedischarge passage 5 and is connected to theintermediate pressure chamber 88 of thecontrol valve 8. Thecommunication hole 213 functions as a venturi portion pressure introduction hole. Thefifth hole 225 of therear body 22 functions as thereturn passage 9 extending from thedrain chamber 89 of thecontrol valve 8 toward theoil pan 100. - As illustrated in
FIGS. 3 and 4 , the longitudinal direction of the venturi portion 50 (the x-axis direction) extends generally perpendicularly to the direction in which the central axis O of the drivingshaft 40 extends (the z-axis direction), and also extends generally in parallel with the longitudinal direction of the control valve 8 (the x-axis direction). Theventuri portion 50 is disposed in such a manner that the upstream side thereof faces thehigh pressure chamber 86 of thecontrol valve 8. In other words, thedischarge passage 5 on the upstream side of theventuri portion 50 and thehigh pressure chamber 86 at least partially overlap each other in the x-axis direction. More specifically, the negative side of the venturi formingblock containing hole 228 in the x-axis direction with respect to theventuri forming block 21, and the high pressure chamber 86 (when thecontrol valve 8 is maximally displaced toward the negative side in the x-axis direction) at least partially overlap each other as viewed from the y-axis direction. - [Functions]
- Next, functions and effects will be described. An upper diagram of
FIG. 6 schematically illustrates thedischarge passage 5 around theventuri portion 50. An arrow indicates the direction in which the hydraulic fluid flows. It is defined that u1 and p1 represent a flow speed and a pressure of the hydraulic fluid in thedischarge passage 5 on the upstream side of theventuri portion 50, respectively. It is defined that u2 and p2 represent a flow speed and a pressure at thesmall diameter portion 51. It is defined that u3 and p3 represent a flow speed and a pressure in thedischarge passage 5 on the downstream side of theventuri portion 50, respectively. A lower diagram ofFIG. 6 illustrates a change in the pressure P that is associated with each of the portions illustrated in the upper diagram. The inner diameter (a cross-sectional area) of thesmall diameter portion 51 is smaller than the inner diameter (a cross-sectional area) of thedischarge passage 5 on the upstream side of theventuri portion 50. Therefore, u2 is higher than u1. This increase in the flow speed is proportional to the flow amount and inversely proportional to a difference in the cross-sectional area. The pressure reduces in a quadratic function manner according to the increase in the flow speed based on Bernoulli's principle. Therefore, p2 is lower than p1. This reduction in the pressure corresponds to the increase in the flow speed, i.e., the flow amount. In this manner, a differential pressure Δp=p1−p2 is generated according to the flow amount at the venturi portion 50 (the small diameter portion 51) as the constriction portion. The inner diameter of the inner diameter gradually-increasingportion 52 gradually increases at theventuri portion 50 as approaching the downstream side. Therefore, the flow speed at the inner diameter gradually-increasingportion 52 gradually reduces as approaching the downstream side. Since the reduction in the flow speed is gentle, energy is not lost so much. Therefore, the pressure in the inner diameter gradually-increasingportion 52 gradually increases as the hydraulic fluid flows toward the downstream side, according to the reduction in the flow speed. If the inner diameter on the downstream side at theventuri portion 50 increases to around the inner diameter of thedischarge passage 5 on the upstream side of theventuri portion 50, the flow speed reduces to around u1, and the pressure increases (recovers) to around p1. Since the inner diameter of the constriction portion on the downstream side (the inner diameter gradually-increasing portion 52) gently increases in this manner, a large loss of energy is prevented or cut down. Therefore, on the downstream side of the constriction portion, the flow speed reduces to a similar level to the upstream side of the constriction portion, and the pressure also recovers to a similar level to the upstream side of the constriction portion. - The hydraulic fluid (p1) on the upstream side of the
venturi portion 50 is introduced into thehigh pressure chamber 86 via thehigh pressure passage 6. The hydraulic fluid (p2) in the venturi portion 50 (the small diameter portion 51) is introduced into theintermediate pressure chamber 88 via theintermediate pressure passage 7. Thedrain chamber 89 is kept at the low pressure (is opened to an atmospheric pressure similarly to the intake passage 3). A force F1 toward the positive side in the x-axis direction due to pi in thehigh pressure chamber 86 and a force F2 toward the negative side in the x-axis direction due to p2 in theintermediate pressure chamber 88 are applied to thecontrol valve 8. Further, a force F3 toward the negative side in the x-axis direction due to thespring 88 is applied to thecontrol valve 8. When the difference between F1 and F2, F1−F2 (the force corresponding to the differential pressure Δp) exceeds F3, thecontrol valve 8 is displaced toward the positive side in the x-axis direction. When thehigh pressure chamber 86 and thereturn passage 9 are brought into communication with each other due to this displacement, the hydraulic fluid introduced from thedischarge passage 5 on the upstream side of theventuri portion 50 to the high pressure passage 6 (the high pressure chamber 86) starts to be returned to the intake passage 3 (one side where theintake ports 230 are located) via thereturn passage 9. In other words, thecontrol valve 8 switches the flow passage in such a manner that the hydraulic fluid is returned toward the intake side based on the differential pressure Δp between the upstream side of theventuri portion 50 and thesmall diameter portion 51. When the hydraulic fluid starts to be returned toward the intake side, the flow amount to be supplied to theCVT 10 via thedischarge passage 5 is limited to a required amount. In this manner, theventuri portion 50, thehigh pressure passage 6, theintermediate pressure chamber 7, thecontrol valve 8, and thereturn passage 9 function as a controller that controls the discharge flow amount of thepump element 4. - In the conventional pump apparatus, the orifice has been used as a means for generating the differential pressure. The orifice can be formed with, for example, such a simple structure that only a constriction of a thin plate is provided in the flow passage. The pressure difference is generated according to the flow amount between the upstream side and the downstream side of the orifice. However, the orifice leads to a turbulence of the flow at an exit of the constriction, thereby resulting in a loss of the energy and thus a reduction in the pressure on the downstream side of the orifice. The lost energy undesirably spreads outward by being converted into heat, noise, and the like. Therefore, the efficiency of the pump undesirably reduces. As the differential pressure is further increasing, the efficiency of the pump is reducing. Hereinafter, a pump apparatus similar to the present exemplary embodiment that uses an
orifice 500 instead of theventuri portion 50 will be referred to as a comparative example. A narrower angle θ at an exit of theorifice 500 is 120 to 180 degrees.FIG. 7 is a similar diagram toFIG. 6 that illustrates the comparative example. An upper diagram ofFIG. 7 illustrates thedischarge passage 5 around theorifice 500. It is defined that u1 and p1 represent the flow speed and the pressure of the hydraulic fluid in thedischarge passage 5 on the upstream side of theorifice 500, respectively. It is defined that u2 and p2 represent the flow speed and the pressure in thedischarge passage 5 on the downstream side of theorifice 500, respectively. An inner diameter of theorifice 500 is smaller than the inner diameter of thedischarge passage 5 on the upstream side of theorifice 500. Therefore, the flow speed at theorifice 500 is higher than and the pressure at theorifice 500 is lower than p1. An inner diameter of the exit of theorifice 500 suddenly increases as approaching the downstream side. Therefore, an eddy current occurs at the exit of theorifice 500, and the energy is significantly lost. Therefore, although u2 reduces to u1, p2 does not increase (recover) to p1. In other words, the pressure undesirably reduces (a pressure loss). The conventional pump apparatus results in supply of the pressure p2 to theCTV 10 after the pressure reduces in this manner. - On the other hand, the
pump apparatus 1 according to the present embodiment uses a venturi tube instead of the orifice as method means for generating the differential pressure. Theventuri portion 50 has the gently increasing inner diameter on the downstream side (the inner diameter gradually-increasing portion 52) of the constriction portion, thereby preventing or cutting down the significant loss of the energy. Therefore, the pressure recovers according to the reduction in the flow speed. In other words, the pressure loss at a differential pressure generation means is prevented or cut down. Therefore, the present embodiment can generate the differential pressure while preventing or reducing the deterioration of the efficiency of the pump. Especially, the automatic transmission such as the stepless transmission uses a larger flow amount compared to a power steering apparatus and the like, and therefore can acquire a considerable effect of preventing or cutting down the pressure loss. An entrance at the constriction portion at the venturi portion 50 (the upstream side of the small diameter portion 51) is also formed in such a manner that the dimeter of the inner diameter gradually-reducingportion 210 gently reduces, which can prevent or reduce the occurrence of the turbulence of the flow. As a result, the energy is not lost significantly, and the pressure reduces according to the increase in the flow speed. Therefore, the present embodiment can further efficiently reduce the pressure (can prevent or cut down the pressure loss as a whole). Therefore, the present embodiment can further improve the efficiency of the pump. - In the comparative example, an attempt to cut down the energy loss at the
orifice 500 to prevent or reduce the deterioration of the efficiency of the pump leads to an unintentional reduction in the differential pressure (the force F1−F2 corresponding thereto). Activating thecontrol valve 8 with the small Δp leads to an unstable behavior of thecontrol valve 8. As a result, a wide variation undesirably occurs in the discharge flow amount of thepump element 4 targeted for the control (hereinafter referred to as a control flow amount). On the other hand, the present embodiment can increase the differential pressure (the force F1−F2 corresponding thereto) while preventing or reducing the deterioration of the efficiency of the pump. Therefore, the present embodiment can also prevent or reduce the above-described variation in the control flow amount.FIG. 8 is a graph indicating a relationship between the discharge flow amount (the flow amount passing through the differential pressure generation means) Q of thepump element 4, and the difference Δp between the pressures applied to the both sides of thecontrol valve 8 in the axial direction (the differential pressure generated at the differential pressure generation means). Supposing that the efficiency of the pump (the pressure loss at the differential pressure generation means) is the same between the present embodiment and the comparative example, a characteristic of the present embodiment is indicated by a solid line, and a characteristic of the comparative example is indicated by an alternate long and short dash line. According to Q, Δp changes in a quadratic curve manner. The activation (displacement) of thecontrol valve 84 is controlled according to Δp, i.e., Q. A change rate of Δp to Q is higher in the present embodiment than in the comparative example. Q required to generate the same level of Δp is smaller in the present embodiment than in the comparative example. In other words, a larger pressure of Δp (the force F1−F2 corresponding thereto) can be generated in the present embodiment than in the comparative example even if Q is the same therebetween. Therefore, the present embodiment can stabilize the behavior of thecontrol valve 8, and prevent or reduce the variation in the control flow amount. - Further, a load from outside (an external force) may be applied to the
control valve 8 besides F1 to F3. In this case, the control flow amount may deviate from an originally intended amount. For example, there is a relatively large amount of contamination in the hydraulic fluid under a use environment in the automatic transmission (the CVT 10). If a load is generated on thecontrol valve 8 due to, for example, the presence of the contamination in a gap between the outer peripheral surface of thecontrol valve 8 and the inner peripheral surface of thevalve containing hole 227, this makes thecontrol valve 8 less movable, thereby undesirably causing the deviation of the control flow amount from the originally intended amount by a flow amount corresponding to this load. On the other hand, in the present embodiment, the differential pressure Δp (the force F1−F2 corresponding thereto) can be considerably changed with a small change in the flow amount Q. Therefore, the deviation of the control amount can be reduced. InFIG. 8 , it is defined that δp represents the above-described load converted into Δp, and δQ represents the deviation of Q corresponding to this δp. In other words, a predetermined amount of Q corresponds to an arbitrary pressure of Δp, and a deviation of the above-described arbitrary pressure of Δp by δp causes a deviation of Q from the above-described predetermined amount of Q by δQ. The change rate of Q to Δp is smaller in the present embodiment than in the comparative example. Therefore, δQ corresponding to the same deviation of δp is smaller in the present embodiment than in the comparative example (δQ2<δQ1). In other words, even when the same load is applied to thecontrol valve 8, the flow amount is less changed in the present embodiment than in the comparative example. Therefore, the present embodiment can reduce the deviation of the control flow amount. - Then, it is also conceivable to increase a gap area of a clearance portion between the
control valve 8 and thevalve containing hole 227 around thecontrol valve 8 to prevent a lock of thecontrol valve 8 due to the contamination. However, the increase in the gap area of the clearance portion leads to an increase in a leak amount around the control valve 8 (via the clearance portion). This results in the undesirable deterioration of the efficiency of the pump. On the other hand, the present embodiment can generate a large differential pressure Δp with a relatively small flow amount Q while preventing or cutting down the energy loss at the constriction portion. Therefore, the diameter of thecontrol valve 8 can be reduced without requiring a significant reduction in the force F1−F2 applied to thecontrol valve 8. Reducing the diameter of thecontrol valve 8 also allows a reduction in the gap area of the above-described clearance portion. As a result, the present embodiment reduces the leak amount around thecontrol valve 8, thereby succeeding in preventing or reducing the deterioration of the pump efficiency. - The narrower angle e sandwiched between the inner walls of the inner diameter gradually-increasing
portion 52 is an angle by which the exit flares at theventuri portion 50 as the constriction portion. Setting θ to 60 degrees or smaller can acquire a sufficient effect of preventing or cutting down the pressure loss.FIG. 9 illustrates a relationship between θ and a pressure loss rate. The pressure loss rate is a rate when the pressure rate in the comparative example is defined to be 1. When θ is 60 degrees or smaller, the pressure loss rate falls below 1. In other words, the pressure loss is smaller than the comparative example. In the present embodiment, the venturi portion 50 (the inner diameter gradually-increasing portion 52) is formed in such a manner that θ becomes 60 degrees or smaller. Therefore, the pressure loss is prevented or cut down more than in the comparative example. Therefore, the present embodiment can further reliably prevent or reduce the deterioration of the pump efficiency. For example, by setting θ to approximately 15 degrees, the present embodiment can prevent or cut down an excessive increase in the length of theventuri portion 50 in the longitudinal direction (a dimension in the axial direction) while acquiring a sufficiency effect of preventing or cutting down the pressure loss. - The space in the venturi forming
block containing hole 228 on the negative side in the x-axis direction with respect to theventuri forming block 21 functions as thedischarge passage 5 on the upstream side of theventuri portion 50. Thesecond hole 222 functions as thedischarge passage 5 on the downstream side of theventuri portion 50. The inner diameter of the venturi formingblock containing hole 228 is larger than the inner diameter of thesecond hole 222. In other words, the above-described space in thedischarge passage 5 on the upstream side of theventuri portion 50 is alarge diameter portion 53 having a larger inner diameter than the downstream side (the second hole 222). The pressure in thislarge diameter portion 53 is introduced into thehigh pressure chamber 86 of thecontrol valve 8 as the pressure on the upstream side of the venturi portion 50 (the high pressure). Therefore,FIG. 6 can be redrawn likeFIG. 10 . InFIG. 10 , it is defined that u1* and p1* represent a flow speed and a pressure in thelarge diameter portion 53. The other symbols are similar toFIG. 6 . If the inner diameter (the cross-sectional area) of thelarge diameter portion 53 is larger than the inner diameter (the cross-sectional area) of thedischarge passage 5 on the upstream side of thelarge diameter portion 53, u1* is lower than u1 (≈u3). According thereto, p1* is higher than p1 (≈p3). The other characteristics are similar toFIG. 6 . Therefore, defining that Δp* represents the differential pressure generated at the venturi portion 50 (the small diameter portion 51), Δp*(=p1*−p2)>Δp(=p1−p2) is satisfied, so that a larger differential pressure is generated than when thelarge diameter portion 53 is not provided (FIG. 6 ). As a result, the difference F1−F2 between the forces applied to thecontrol valve 8 increases, so that the present embodiment can further effectively acquire the above-described functions and effects. - The inner diameter of the end of the inner diameter gradually-increasing
portion 52 on the other end in the axial direction that is opened on the end surface of theventuri forming block 21 on the other side in the axial direction is slightly smaller than the inner diameter of thesecond hole 222. Therefore,FIG. 6 can be redrawn likeFIG. 11 . The inner diameter gradually-increasingportion 52 includes the taper portion on the upstream side that is formed so as to keep θ constant at 60 degrees or smaller (in particular, approximately 15 degrees), and a stepped portion on the downstream side that is formed so as to have θ larger than 60 degrees continuously from thedischarge passage 5 on the downstream side of theventuri portion 50. Hereinafter, the above-described taper portion on the upstream side will be referred to as afront portion 520, and the above-described stepped portion on the downstream side will be referred to as arear portion 521. The inner diameter gradually-increasingportion 52 includes thefront portion 520 and therear portion 521. In the present embodiment, θ of therear portion 521 is approximately 180 degrees. In other words, therear portion 521 flares as if extending generally perpendicularly to the inner walls of thedischarge passage 5 on the downstream side of theventuri portion 50. Hypothetically supposing that the inner diameter gradually-increasingportion 52 is formed as far as the inner diameter thereof reaches the same diameter as the inner diameter of thedischarge passage 5 on the downstream side of theventuri portion 50 with θ kept constant at 60 degrees or smaller, L0 is defined to represent a length of this (hypothetical) inner diameter gradually-increasingportion 52 in the longitudinal direction at this time. Then, L is defined to represent a length of thefront portion 520 in the longitudinal direction. -
FIG. 12 illustrates a relationship between L/L0, which is a ratio of L to L0, and the pressure loss rate. The pressure loss rate is a rate of a pressure loss when L/L0 is 0, i.e., a rate when the pressure loss in the comparative example is defined to 1. In a range where L/L0 is higher than 0 and equal to or lower than 0.65, the pressure loss rate reduces according to the increase in L/L0. In a range where L/L0 is higher than 0.65, the pressure loss rate does not reduce more than that even when L/L0 increases. Therefore, as long as a region of a certain length is ensured as the region where θ is 60 degrees or smaller (the front portion 520), the pressure loss can be more prevented or cut down than in the comparative example. However, even if the length L of thefront portion 520 increases to longer than 65% of L0, this does not achieve the effect of preventing or cutting down the pressure loss more than that. Therefore, it is preferable to form thefront portion 520 in such a manner that the L/L0 exceeds 0 and reaches or falls below 0.65, i.e., as far as a position where L reaches or falls below 65% of L0. In this case, therear portion 521 where θ exceeds 60 degrees is provided on the downstream side of thefront portion 520. Stopping keeping θ at 60 degrees or smaller at therear portion 521 in this manner allows theventuri portion 50 to be formed continuously from the discharge passage 5 (the inner diameter of theventuri portion 50 to be returned to the initial diameter) on the downstream side, with a relatively short length (shorter than L0). As a result, the present embodiment can reduce the length of theventuri portion 50 in the longitudinal direction. The present embodiment can improve the above-described effect of reducing the length by allowing θ at therear portion 521 to approach generally 180 degrees as illustrated inFIG. 11 . In the range where L/L0 is higher than 0 and equal to or lower than 0.65, a reduction amount (a reduction rate) of the pressure loss rate with respect to the increase in L/L0 increases as L/L0 approaches 0. Then, in a range where L/L0 is 0.4 or higher, a sufficiently low pressure loss rate (sufficiently close to the pressure loss rate when L/L0 is 0.65) can be acquired. Therefore, it is preferable to form thefront portion 520 in such a manner that L/L0 reaches or exceeds 0.4, i.e., as far as a position where L reaches or exceeds 40% of L0. In this case, the present embodiment can improve the above-described effect of reducing the length by allowing L to approach 40% of L0 while acquiring the sufficient effect of preventing or cutting down the pressure loss. - The
venturi portion 50 is long compared to the orifice (the dimension in the axial direction is large). Therefore, processing thereof is comparatively difficult. On the other hand, in the present embodiment, theventuri portion 50 is formed in theventuri forming block 21. Thisventuri forming block 21 is joined to the pump housingmain body 20. - As a result, the
venturi portion 50 is realized inside the pump housingmain body 20. In this manner, the present embodiment can improve workability of theventuri portion 50 by forming theventuri portion 50 in theventuri forming block 21 that is a separate member from the pump housingmain body 20. The present embodiment can be realized by forming at least thesmall diameter portion 51 and the inner diameter gradually-increasingportion 52 constituting theventuri portion 50 in theventuri forming block 21. In other words, the constriction portion having the same diameter as thesmall diameter portion 51 and a predetermined length and the inner diameter gradually-reducingportion 210 may be provided on the pump housingmain body 20 side, or may be provided on theventuri forming block 21 side. Theventuri forming block 21 is made from the resin material. Theventuri portion 50 including the inner diameter gradually-increasingportion 52 is formed by molding. Therefore, the inner diameter gradually-increasingportion 52 can be easily formed compared to forming the inner diameter gradually-increasingportion 52 by machining processing. - Further, the
venturi portion 50 should have a long dimension (a large space in the longitudinal direction) compared to the orifice. On the other hand, in the present embodiment, theventuri portion 50 is disposed in such a manner that the longitudinal direction of the venturi portion 50 (the x-axis direction) and the direction of the rotational axis (the central axis O) of the driving shaft 40 (the z-axis direction) extend generally perpendicularly to each other. - Therefore, the present embodiment can prevent or cut down an increase in the dimension of the pump apparatus in the direction of the rotational axis of the driving shaft 40 (the axial direction). On the other hand, the
pump housing 2 has a dimension enough to contain thecontrol valve 8 therein from the beginning. Then, in the present embodiment, theventuri portion 50 is disposed in such a manner that the longitudinal direction of theventuri portion 50 and the longitudinal direction of thecontrol valve 8 extend generally in parallel with each other. Theventuri portion 50 is disposed so as to utilize the originally existing space extending in the longitudinal direction of thecontrol valve 8 in this manner, so that the present embodiment can prevent or cut down the increase in a size of an outer shape of the pump apparatus (in the radial direction of the control valve 8). - Further, the
venturi portion 50 is disposed in such a manner that thedischarge passage 5 on the upstream side of theventuri portion 50 faces thehigh pressure chamber 86 of thecontrol valve 8. Therefore, the present embodiment can shorten the high pressure passage 6 (the first hole 221) establishing the communication between the upstream side of theventuri portion 50 and thehigh pressure chamber 86. More specifically, both the venturi formingblock containing hole 228 and thevalve containing hole 227 extend in the x-axis direction and are disposed generally in parallel with each other. Thefirst hole 221 extends linearly in the y-axis direction, and connects the negative side of the venturi formingblock containing hole 228 in the x-axis direction with respect to theventuri forming block 21 and thehigh pressure chamber 86 in thevalve containing hole 227 to each other, thereby connecting the upstream side of theventuri portion 50 and thehigh pressure chamber 86 with a shortest distance. Theventuri portion 50 may be disposed in such a manner that the second communication groove 215 (at least a part thereof) in theventuri forming block 21 faces theintermediate pressure chamber 88 of thecontrol valve 8. In this case, the present embodiment can shorten the intermediate pressure passage 7 (the fourth hole 224) establishing the communication between thesecond communication groove 215 and theintermediate pressure chamber 88. - The communication holes 213 of the
venturi forming block 21 are opened on the inner peripheral surface of theventuri portion 50 on the radially inner side. The communication holes 213 are provided in theventuri portion 50, and function as openings for introducing the pressure in theventuri portion 50 into the control valve 8 (the intermediate pressure chamber 88). Then, due to presence of, for example, a bend or a curve in thedischarge passage 5 on the upstream side of theventuri portion 50, thispassage 5 may have unevenness in a flow speed distribution in a direction around the axis line along the longitudinal direction thereof(hereinafter referred to as a circumferential direction). This case also leads to occurrence of unevenness in a pressure distribution in the circumferential direction in theventuri portion 50. This unevenness undesirably varies depending on the flow amount and a temperature condition. On the other hand, in the present embodiment, the plurality of (four) openings is provided in the circumferential direction of theventuri portion 50 as the above-described openings of the communication holes 213. The pressure is extracted from a plurality of portions in the circumferential direction in theventuri portion 50 in this manner, which allows the pressure in theventuri portion 50 to be stably introduced into theintermediate pressure chamber 88 in spite of the above-described unevenness in the pressure distribution. In other words, the pressures (the hydraulic fluid) extracted from the above-described openings of the plurality ofcommunication holes 213 are collected into the single intermediate pressure passage 7 (the fourth hole 224) via the first andsecond communication grooves intermediate pressure chamber 88. At this time, the above-described uneven pressure distributions are canceled out by each other, which results in introduction of an average pressure in the circumferential direction in theventuri portion 50 into theintermediate pressure chamber 88. Therefore, the variation in the pressure extracted from inside theventuri portion 50 is reduced. Therefore, the activation of thecontrol valve 8 is stabilized, and the deviation of the control flow amount is reduced. The number ofcommunication holes 213 may be any number as long as this number is two or more. In the present embodiment, the above-described openings of the communication holes 213 are disposed at generally equal intervals in the circumferential direction, so that the present embodiment can further stably reduce the variation in the pressure extracted from inside theventuri portion 50. - The communication holes 213 are provided at the positions overlapping the
small diameter portion 51 in the axial direction (the longitudinal direction) of theventuri portion 50. In other words, the above-described openings of the communication holes 213 are provided at thesmall diameter portion 51. Therefore, this configuration results in extraction of the pressure from a portion smallest in diameter in theventuri portion 50, i.e., a portion in theventuri portion 50 where the pressure is minimized, and introduction of this pressure into theintermediate pressure chamber 88. As a result, the present embodiment can most efficiently utilize the differential pressure generated in theventuri portion 50. - The
pump apparatus 1 according to a second embodiment is different from the first embodiment in terms of the configuration of theventuri forming block 21. The second embodiment will be described below focusing on only configurations different from the first embodiment. Configurations shared with the first embodiment will be identified by the same reference numerals as the first embodiment, and descriptions thereof will be omitted.FIG. 13 illustrates a cross section acquired by cutting theventuri forming block 21 along a plane passing through the central axis of theventuri portion 50. Theventuri forming block 21 is not provided with the inner diameter gradually-reducingportion 210 like the first embodiment. Thesmall diameter portion 51 is opened on the end surface of theventuri forming block 21 on the one side in the axial direction (the outer surface of the venturi forming block 21). Thecommunication hole 213 is provided at the position overlapping the one side of the inner diameter gradually-increasingportion 52 in the axial direction (the one side where thesmall diameter portion 51 is located). A radially inner end of thecommunication hole 213 is opened to the one side of the inner diameter gradually-increasingportion 52 in the axial direction (the one side where thesmall diameter portion 51 is located). Thecommunication hole 213 forms a part of theintermediate pressure passage 7. Thecommunication hole 213 introduces a pressure on the one side of the inner diameter gradually-increasingportion 52 in the axial direction (the one side where thesmall diameter portion 51 is located) among pressures in theventuri portion 50 into theintermediate pressure chamber 88 of thecontrol valve 8. - Next, functions will be described. Like the present embodiment, the pressure in the
venturi portion 50 that is introduced into theintermediate pressure chamber 88 may be not only the pressure in thesmall diameter portion 51 but also the pressure in the inner diameter gradually-increasingportion 52. The pressure on the one side of the inner diameter gradually-increasingportion 52 in the axial direction (the one side where thesmall diameter portion 51 is located) is introduced into theintermediate pressure chamber 88. Therefore, a lower pressure among the pressures in the inner diameter gradually-increasingportion 52 can be used. Therefore, the present embodiment allows a sufficiently large differential pressure to be applied to thecontrol valve 8. - If the
small diameter portion 51 is not opened on the outer surface of theventuri forming block 21 and is provided inside theventuri forming block 21, a mold would have to be inserted from the both sides of theventuri forming block 21 in the axial direction when theventuri portion 50 is formed by molding. When theventuri portion 50 is subjected to the machining processing, the machining processing would have to be performed from the both sides of theventuri forming block 21 in the axial direction. On the other hand, in the present embodiment, thesmall diameter portion 51 is opened on the outer surface of theventuri forming block 21. Therefore, when theventuri portion 50 is formed by molding, this can be achieved by inserting the mold only from the opening side of the inner diameter gradually-increasingportion 52 in the axial direction of theventuri forming block 21. When theventuri portion 50 is subjected to the machining processing, this can be achieved by performing the machining processing only from the opening side of the inner diameter gradually-increasingportion 52 in the axial direction of theventuri forming block 21. Therefore, manufacturability of the venturi portion 50 (the venturi forming block 21) can be improved. - In the
pump apparatus 1 according to a third embodiment, the pump housingmain body 20 is made from a metallic material similarly to the first embodiment. On the other hand, theventuri forming block 21 is also made from a metallic material unlike the first embodiment. More specifically, theventuri forming block 21 is made from a sintered material. Theventuri portion 50 is formed with use of a mold when metallic powder is molded by being compacted in a powder compacting process. This compact is sintered, by which theventuri forming block 21 is formed. - If the
pump apparatus 1 is configured in such a manner that theventuri forming block 21 is joined to the pump housing main body 20 (the venturi formingblock containing hole 228 of the rear body 22), this configuration can raise a problem such as occurrence of a distortion between theventuri forming block 21 and the pump housingmain body 20 after theventuri forming block 21 is joined to the pump housingmain body 20. On the other hand, in the present embodiment, theventuri forming block 21 is made from the metallic material. Therefore, theventuri forming block 21 has a similar linear expansion coefficient to the pump housingmain body 20. Therefore, the present embodiment can prevent or reduce occurrence of a problem like the above-described example. Further, the venturi portion 50 (the inner diameter gradually-increasingportion 52 and the like) is formed with use of the mold. Therefore, theventuri portion 50 can be easily formed compared to forming the venturi portion 50 (the inner diameter gradually-increasingportion 52 and the like) by the machining processing. - The
pump apparatus 1 according to a fourth embodiment is different from the first embodiment in terms of the layout of theventuri portion 50 and the like. The fourth embodiment will be described below focusing on only configurations different from the first embodiment. Configurations shared with the first embodiment will be identified by the same reference numerals as the first embodiment, and descriptions thereof will be omitted.FIG. 14 illustrates thepump housing 2 as viewed from the direction in which the driving shaft 40 (the central axis O) extends (as viewed from the negative side in the z-axis direction), and a part of an inner structure and contained components are indicated by broken lines.FIG. 15 illustrates a cross section as viewed from a line B-B illustrated inFIG. 14 . An orthogonal coordinate system is set in a similar manner to the first embodiment (FIG. 3 and the like). Thepump housing 2 does not include theventuri forming block 21 like the first embodiment. The pump housing main body 20 (the rear body 22) does not include the venturi formingblock containing hole 228 like the first embodiment. The inner diameter gradually-reducingportion 210 and theventuri portion 50 are directly formed inside therear body 22. - The inner diameter gradually-reducing
portion 210 and theventuri portion 50 extend in the z-axis direction on the positive side of therear body 22 in the x-axis direction and the negative side of therear body 22 in the y-axis direction. In other words, the longitudinal direction of theventuri portion 50 extends generally in parallel with the direction of the central axis O (the z-axis direction) and also extends perpendicularly to the longitudinal direction of the valve containing hole 227 (the x-axis direction). Theventuri portion 50 does not overlap the containing recessedportion 220 in the direction perpendicular to the z axis (the radial direction of the rotational axis of the driving shaft 40) (theventuri portion 50 is located on the radially outer side with respect to the containing recessed portion 220), but overlaps the containing recessedportion 220 in the z-axis direction. The inner diameter gradually-reducingportion 210 includes a first inner diameter gradually-reducingportion 210 a where a narrower angle sandwiched between inner walls thereof is relatively large, and a second inner diameter gradually-reducingportion 210 b where a narrower angle thereof is relatively small. An end of the first inner diameter gradually-reducingportion 210 a on the positive side in the z-axis direction is opened on the surface of therear body 22 on the positive side in the z-axis direction. An inner diameter of the first inner diameter gradually-reducingportion 210 a gradually reduces from the positive side toward the negative side in the z-axis direction. An end of the second inner diameter gradually-reducingportion 210 b on the positive side in the z-axis direction is connected to an end of the first inner diameter gradually-reducingportion 210 a on the negative side in the z-axis direction. An inner diameter of the second inner diameter gradually-reducingportion 210 b gradually reduces from the positive side toward the negative side in the z-axis direction. An end of thesmall diameter portion 51 on the positive side in the z-axis direction is connected to an end of the second inner diameter gradually-reducingportion 210 b on the negative side in the z-axis direction. An end of thesmall diameter portion 51 on the negative side in the z-axis direction is connected to an end of the inner diameter gradually-increasingportion 52 on the positive side in the z-axis direction. The inner diameter of the inner diameter gradually-increasingportion 52 gradually increases from the positive side toward the negative side in the z-axis direction. An end of the inner diameter gradually-increasingportion 52 on the negative side in the z-axis direction is opened on the surface of therear body 22 on the negative side in the z-axis direction. - The
second hole 222 extends in the z-axis direction on the negative side of therear body 22 in the x-axis direction and the negative side of therear body 22 in the y-axis direction. An end of thesecond hole 222 on the negative side in the z-axis direction is connected to an end of thefirst hole 221 on the negative side in the y-axis direction. An end of thesecond hole 222 on the positive side in the z-axis direction is opened on the surface of therear body 22 on the positive side in the z-axis direction. Thethird hole 223 is formed inside thefront body 24 and is disposed so as to extend in the x-axis direction. An end of thethird hole 223 on the negative side in the x-axis direction is bent toward the negative side in the z-axis direction and opened on the surface of thefront body 24 on the negative side in the z-axis direction, and is also connected to the end of thesecond hole 222 on the positive side in the z-axis direction. An end of thethird hole 223 on the positive side in the x-axis direction is bent toward the negative side in the z-axis direction and opened on the surface of thefront body 24 on the negative side in the z-axis direction, and is also connected to the end of the first inner diameter gradually-reducingportion 210 a on the positive side in the z-axis direction. An inner diameter of the end of the first inner diameter gradually-reducingportion 210 a on the positive side in the z-axis direction is approximately equal to an inner diameter of thethird hole 223. Thefourth hole 224 connects the end of thevalve containing hole 227 on the positive side in the x-axis direction and thesmall diameter portion 51 of theventuri portion 50. - Next, functions and effects will be described. The
pump housing 2 does not include theventuri forming block 21, and the inner diameter gradually-reducingportion 210 and theventuri portion 50 are directly formed inside the pump housing 2 (the rear body 22). Therefore, the present embodiment can reduce the number of components. - The
venturi portion 50 should have a long dimension (a large space in the longitudinal direction) compared to the orifice. On the other hand, thepump housing 2 has a dimension of the drivingshaft 40 in the rotational axis direction that is enough to contain thepump element 4 therein from the beginning. In the present embodiment, theventuri portion 50 is disposed so as to be located on the radially outer side with respect to the pump element containing portion (the containing recessed portion 220) and overlap the pump element containing portion (the containing recessed portion 220) in the direction of the rotational axis (the central axis O) of the drivingshaft 40. Theventuri portion 50 is disposed so as to utilize the originally existing space extending in the direction of the rotational axis of the drivingshaft 40 in this manner, by which the present embodiment can prevent or cut down the increase in the size of the outer shape of the pump element 1 (in the direction of the rotational axis of the driving shaft 40). Further, theventuri portion 50 is disposed in such a manner that the longitudinal direction of theventuri portion 50 and the direction of the rotational axis (the central axis O) of the drivingshaft 40 extend generally in parallel with each other. Therefore, the present embodiment can prevent or cut down the increase in the dimension of thepump apparatus 1 in the radial direction of the rotational axis of the drivingshaft 40. The functions and effects due to the above-described layout can also be acquired even when theventuri portion 50 is formed in theventuri forming block 21. - The
pump apparatus 1 according to a fifth embodiment is different from the first embodiment in terms of the housing where theventuri portion 50 and thecontrol valve 8 are set up. The fifth embodiment will be described below focusing on only differences from the first embodiment. Atransmission housing 10 a is a housing of the CVT unit, and is a separate member from thepump housing 2. Thepump housing 2 may be disposed integrally with thetransmission housing 10 a, or may be spaced apart from thetransmission housing 10 a. While thepump element 4 is provided in thepump housing 2, theventuri portion 50 and thecontrol valve 8 are provided in the transmission housing (for example, a housing of the control valve) 10 a as indicated by a broken line illustrated inFIG. 1 . - In this manner, the
venturi portion 50 or thecontrol valve 8 is not provided on thepump housing 2 side but is provided on thetransmission housing 10 a side, by which the present embodiment can reduce the size of the unit including thepump element 4 and improve layout flexibility thereof. When thecontrol valve 8 is provided on thetransmission housing 10 a side, the hydraulic fluid supplied from the pump element 4 (the pump housing 2) to thetransmission housing 10 a is a flow amount before the hydraulic fluid is controlled by thecontrol valve 8. Thecontrol valve 8 controls the flow amount of the hydraulic fluid to be supplied from thepump element 4 to theCVT 10. The above-described “flow amount of the hydraulic fluid to be supplied from thepump element 4 to theCVT 10” means a flow amount to be actually supplied to theCVT 10 existing inside thetransmission housing 10 a. As indicated by an alternate long and short dash line inFIG. 1 , theventuri portion 50 may be provided in thetransmission housing 10 a, and thepump element 4 and thecontrol valve 8 may be provided in thepump housing 2. Further, theventuri portion 50 and thecontrol valve 8 may be provided in a housing other than thetransmission housing 10 a. - The pump element according to a sixth embodiment is a variable displacement pump in which the pump capacity is variably controlled. The sixth embodiment will be described below focusing on only configurations different from the first embodiment. Configurations shared with the first embodiment will be identified by the same reference numerals as the first embodiment, and descriptions thereof will be omitted.
FIG. 16 is a similar view toFIG. 2 that schematically illustrates a configuration of thepump apparatus 1.FIG. 17 illustrates a partial cross section acquired by cutting thepump housing 2 along the plane including the central axis O. The z axis is set to a horizontal direction inFIG. 17 , and a positive side thereof is set to a right side inFIG. 17 . The containing recessedportion 220, anintake pressure chamber 220 a, thedischarge pressure chamber 226, thevalve containing hole 227, the venturi forming block containing hole (not illustrated), abearing holding hole 229, and the plurality ofpassages 3 and the like are formed in therear body 22. The plurality ofpassages 3 and the like include theintake passage 3, thedischarge passage 5, thehigh pressure passage 6, theintermediate pressure passage 7, afirst control passage 60, asecond control passage 70, and thereturn passage 9. Theintake pressure chamber 220 a and thedischarge pressure chamber 226 are opened to the bottom portion of the containing recessedportion 220. A bush 401 as a bearing is mounted on an inner periphery of thebearing holding hole 229. The end of thevalve containing hole 227 on the negative side in the x-axis direction is opened on the outer surface of therear body 22. Asolenoid 80 is fitted in this opening via aseal member 253. Arod 800 protrudes from thesolenoid 80 toward the positive side in the x-axis direction. - A
shaft containing hole 234 is provided at theside plate 23. Theintake port 230, thedischarge port 231, an intake-side backpressure port 232, and a discharge-side backpressure port 233 are provided at the surface of theside plate 23 on the one side in the axial direction. Theintake port 230 and thedischarge port 231 are grooves extending in the circumferential direction in a generally circular-arc manner, and are provided at positions opposite of theshaft containing hole 234 from each other. The intake-side backpressure port 232 is a groove extending in the circumferential direction in a generally circular-arc manner on one side closer to the shaft containing hole 234 (the radially inner side) with respect to theintake port 230, and is provided in a range overlapping theintake port 230 in the circumferential direction. The discharge-side backpressure port 233 is a groove extending in the circumferential direction in a generally circular-arc manner on the radially inner side with respect to thedischarge port 231, and is provided in a range overlapping thedischarge port 231 in the circumferential direction. Theintake port 230 and the intake-side backpressure port 232 are connected to theintake pressure chamber 220 a of therear body 22 via a communication passage in theside plate 23. Thedischarge port 231 and the discharge-side backpressure port 233 are connected to thedischarge pressure chamber 226 via a communication passage in theside plate 23. An annular seal groove is formed on the surface of theside plate 23 on the negative side in the z-axis direction so as to surround an outer edge of theside plate 23. Anannular seal member 250 is mounted in this seal groove. An annular seal groove is formed on the surface of the bottom portion of the containing recessedportion 220 on the positive side in the z-axis direction so as to surround an opening of thebearing holding hole 229. Anannular seal member 251 is mounted in this seal groove. An annular seal groove is formed on the surface of the bottom portion of the containing recessedportion 220 on the positive side in the z-axis direction so as to surround an outer periphery of an opening of thedischarge pressure chamber 226. Anannular seal member 252 is mounted in this seal groove. Theseal member 252 defines a high pressure region and a low pressure region on an inner peripheral side and an outer peripheral side of theseal member 252, respectively. - A
bush 402 as a bearing is mounted on an inner periphery of abearing holding hole 244 of thefront body 24. Anintake port 240 and adischarge port 241, and an intake-side backpressure port 242 and a discharge-side backpressure port 243 are formed on the end surface of thefront body 24 on the negative side in the z-axis direction at positions generally corresponding in the z-axis direction to theindividual ports individual ports side plate 23 and with similar shapes to them, respectively. Thefront body 24 is fixed by being fastened to therear body 22 with use of abolt 26. - An
adapter ring 44 is mounted in the containing recessedportion 220 of therear body 22 on the positive side of theside plate 23 in z-axis direction. Theadapter ring 44 has an annular shape, and an outer periphery of theadapter ring 44 is fitted to the inner periphery of the containing recessedportion 220. An inner peripheral surface of theadapter ring 44 has a generally cylindrical shape extending in the z-axis direction and is generally ecliptic as viewed from the z-axis direction. Afirst groove portion 441, asecond groove portion 442, a firstflat surface portion 443, a second flat surface portion 444, and a recessedportion 445 are provided on this inner peripheral surface. Thefirst groove portion 441 has a semi-cylindrical shape extending in the z-axis direction, and is provided on the firstflat surface portion 443. The first andsecond control passages first groove portion 441 so as to radially penetrate through theadapter ring 44. Thesecond groove portion 442 is provided on an opposite side of a center (a central axis) of theadapter ring 44 from thefirst groove portion 441, and extends in the z-axis direction. The second flat surface portion 444 is provided between the first andsecond groove portions 441 and 442 (a generally middle position therebetween) in a circumferential direction of theadapter ring 44. The recessedportion 445 is provided on an opposite side of the center of theadapter ring 44 from the second flat surface portion 444. - The
pump element 4 is contained in a space surrounded by an inner peripheral surface of theadapter ring 44, the surface of theside plate 23 on the positive side in the z-axis direction, and the surface of thefront body 24 on the negative side in the z-axis direction. In other words, the above-described space functions as the pump element containing portion. Eleven slits 410 are provided at therotor 41. Thecam ring 43 is annularly formed, and the inner peripheral surface thereof has a generally cylindrical shape. A semi-cylindrical groove portion 433 extending in the z-axis direction is provided on an outer peripheral surface of thecam ring 43. Thecam ring 43 is provided in the pump element containing portion so as to surround therotor 41. Thecam ring 43 forms the plurality ofpump chambers 400 together with therotor 41 and thevanes 42. In other words, theside plate 23 and thefront body 24 are disposed on the side surfaces of thecam ring 43 and therotor 41 in the axial direction. The space between the inner peripheral surface of thecam ring 43 and the outer peripheral surface of therotor 41 is sealingly closed on the both sides thereof in the axial direction by theside plate 23 and thefront body 24, while being divided into the elevenpump chambers 400 by the plurality ofvanes 42. - The
cam ring 43 is provided displaceably in the pump element containing portion. A pin 453 is installed by being fitted between thefirst groove portion 441 of theadapter ring 44 and the groove portion 433 of thecam ring 43. The pin 453 is fixed to thepump housing 2. The pin 453 prevents or reduces a rotation of theadapter ring 44 relative to thepump housing 2 and also prevents or reduces a rotation of thecam ring 43 relative to theadapter ring 44. Thecam ring 43 is contained on the inner peripheral side of theadapter ring 44 swingably relative to thepump housing 2. Thecam ring 43 is supported on the firstflat surface portion 443 relative to theadapter ring 44. Thecam ring 43 swings with the firstflat surface portion 443 serving as a supporting point thereof by being displaced while rolling on the firstflat surface portion 443. Hereinafter, an amount by which a center (a central axis) of the inner peripheral surface of thecam ring 43 is offset from the center (the central axis O) of the rotor 41 (the driving shaft 40) will be referred to as aneccentric amount 5. - A
seal member 46 is mounted in thesecond groove portion 442 of theadapter ring 44. When thecam ring 43 swings, the firstflat surface portion 443 of theadapter ring 44 contacts the outer peripheral surface of thecam ring 43 and theseal member 46 also contacts the outer peripheral surface of thecam ring 43. The above-described space between the inner peripheral surface of theadapter ring 44 and the outer peripheral surface of thecam ring 43 is liquid-tightly divided into a pair of spaces by the first flat surface portion 443 (a portion thereof in abutment with the outer peripheral surface of the cam ring 43) and theseal member 46. In other words, twofluid pressure chambers cam ring 43 and the pump element containing portion. For convenience of the description, an X axis and a Y axis are set to a long-axis direction and a short-axis direction of the generally ecliptic inner peripheral surface of theadapter ring 44, respectively, as illustrated inFIG. 16 . On the outer peripheral side of thecam ring 43, a firstfluid pressure chamber 61 is defined on the negative side in the X-axis direction that is one side where the eccentric amount δ increases, and a secondfluid pressure chamber 71 is defined on the positive side in the X-axis direction that is the other side where δ reduces. When δ increases, a volume of the firstfluid pressure chamber 61 reduces and a volume of the secondfluid pressure chamber 71 increases. One end of a spring 47 is set in the recessedportion 445 of theadapter ring 44 inside the secondfluid pressure chamber 71. The other end of the spring 47 is set on the outer peripheral side of thecam ring 43. The spring 47 is mounted in a compressed state, and constantly biases thecam ring 43 relative to theadapter ring 44 toward the negative side in the X-axis direction (the one side where the firstfluid pressure chamber 61 is located). The displacement of thecam ring 43 toward the negative side in the X-axis direction is regulated by abutment of the outer peripheral surface of thecam ring 43 with the second flat surface portion 444 of theadapter ring 44 inside the firstfluid pressure chamber 61. - The
rotor 41 rotates in a clockwise direction inFIG. 16 . With the center of thecam ring 43 located eccentrically from the central axis O (toward the negative side in the X-axis direction), a radial distance between the outer peripheral surface of therotor 41 and the inner peripheral surface of the cam ring 43 (a radial dimension of the pump chamber 400) increases as approaching the negative side in the X-axis direction from the positive side in the X-axis direction. Thevane 42 projects from theslit 410 and retracts into theslit 410 according to this change in the distance, by which each of thepump chamber 400 is defined. The volume of thepump chamber 400 on the negative side in the X-axis direction becomes larger than the volume of thepump chamber 400 on the positive side in the X-axis direction. Due to this difference in the volume of thepump chamber 400, the volume of thepump chamber 400 reduces as therotor 41 rotates (as thepump chamber 400 travels toward the positive side in the X-axis direction) on the positive side in the Y-axis direction with respect to the central axis O, while increasing as therotor 41 rotates (as thepump chamber 400 travels toward the negative side in the X-axis direction) on the negative side in the Y-axis direction with respect to the central axis O. Thepump chamber 400 periodically expands and contracts while rotating in the clockwise direction around the central axis O. Theintake port 230 is opened to the intake region where the volume of thepump chamber 400 increases according to the rotation of the drivingshaft 40. Thedischarge port 231 is opened to the discharge region where the volume of thepump chamber 400 reduces according to the rotation of the drivingshaft 40. - The
intake passage 3 connects theoil pan 100 and theintake pressure chamber 220 a to each other. Thedischarge passage 5 connects thedischarge pressure chamber 226 and theCVT 10 to each other. Thehigh pressure passage 6 branches off from thedischarge passage 5 on the upstream side of theventuri portion 50 in thedischarge passage 5, and is connected to the positive side of thevalve containing hole 227 in the x-axis direction. Theintermediate pressure passage 7 branches off from the venturi portion 50 (the small diameter portion 51) in thedischarge passage 5 and is connected to the negative side of thevalve containing hole 227 in the x-axis direction. Thefirst control passage 60 and thesecond control passage 70 connect thecontrol valve 8 and thepump element 4 to each other. Thefirst control passage 60 is connected to the positive side of thevalve containing hole 227 in the x-axis direction with respect to thehigh pressure passage 6, and is also connected to the firstfluid pressure chamber 61 by penetrating through theadapter ring 44. Thesecond control passage 70 is connected to the negative side of thevalve containing hole 227 in the x-axis direction with respect to theintermediate pressure passage 7, and is also connected to the secondfluid pressure chamber 71 by penetrating through theadapter ring 44. Thereturn passage 9 is connected to between thefirst control passage 60 and thesecond control passage 70 in thevalve containing hole 227. Regardless of the displacement of thecontrol valve 8 inside thevalve containing hole 227, thehigh pressure passage 6 is opened to thehigh pressure chamber 86, theintermediate pressure passage 7 is opened to theintermediate pressure chamber 88, and thereturn passage 9 is opened to thedrain chamber 89. - The
control valve 8 switches the flow passage of the hydraulic fluid between thefirst control passage 60 and thesecond control passage 70. In an initial state where thecontrol valve 8 is maximally displaced toward the negative side in the x-axis direction, an opening portion of thefirst control passage 60 in thevalve containing hole 227 is in communication with thedrain chamber 89 while being out of communication with thehigh pressure chamber 86 due to thefirst land portion 8. In the same initial state, an opening portion of thesecond control passage 70 is in communication with theintermediate pressure chamber 88 while being out of communication with thedrain chamber 89 due to thesecond land portion 82. As a result, the hydraulic fluid in theintermediate pressure chamber 88 flows into the secondfluid pressure chamber 71. The high pressure is not supplied into the firstfluid pressure chamber 61 and the intermediate pressure is supplied into the secondfluid pressure chamber 71, so that thecam ring 43 is displaced into an eccentric state. Therefore, the pump discharge flow amount increases according to the number of rotations. With thecontrol valve 8 displaced toward the positive side in the x-axis direction by a predetermined amount or more, the opening portion of thefirst control passage 60 is in communication with thehigh pressure chamber 86 while being out of communication with thedrain chamber 89 due to thefirst land portion 81. In the same state, the opening portion of thesecond control passage 70 is in communication with thedrain chamber 89 while being out of communication with theintermediate pressure chamber 88 due to thesecond land portion 82. As a result, the flow passage is switched, so that the hydraulic fluid in thehigh pressure chamber 86 starts to flow into the firstfluid pressure chamber 61 via thefirst control passage 60. The high pressure is supplied into the firstfluid pressure chamber 61, and the intermediate pressure is not supplied into the secondfluid pressure chamber 71. Therefore, the eccentric amount δ of thecam ring 43 reduces and the pump capacity reduces, so that the pump discharge flow amount does not increase even when the number of rotations of the pump increases. In other words, thecontrol valve 8 switches the flow passage in such a manner that the hydraulic fluid introduced via thehigh pressure passage 6 is introduced into the firstfluid pressure chamber 61 based on the differential pressure Δp between the upstream side and thesmall diameter portion 51 of theventuri portion 50. When the hydraulic fluid starts to be introduced into the firstfluid pressure chamber 61, the flow amount to be supplied to theCVT 10 via thedischarge passage 5 is limited to a required amount. In this manner, theventuri portion 50, thehigh pressure passage 6, theintermediate pressure passage 7, thecontrol valve 8, thefirst control passage 60, thesecond control passage 70, the firstfluid pressure chamber 61, and the secondfluid pressure chamber 71 function as a controller that controls the discharge flow amount of thepump element 4. - The activation of the
control valve 8 is controlled based on the differential pressure Δp applied to the both sides of thecontrol valve 8 in the axial direction according to the discharge flow amount of thepump element 4, and is also controlled based on a thrust force applied from thesolenoid 80 to thecontrol valve 8. In other words, a distal end of therod 800 of thesolenoid 80 is in abutment with the end surface of thecontrol valve 8 on the negative side in the x-axis direction. Therod 800 is displaceable in the x-axis direction due to an electromagnetic force generated by thesolenoid 80. Thecontrol valve 8 is subjected to a force F4 applied from thesolenoid 80 toward the positive side in the x-axis direction via therod 800. The thrust force F4 of thesolenoid 80 is controlled based on an instruction from the CVT control unit. When a sum of the difference between F1 and F2, i.e., F1−F2 (the force corresponding to the differential pressure Δp) and F4 (F1−F2+F4) exceeds F3, thecontrol valve 8 is displaced toward the positive side in the x-axis direction. With thesolenoid 80 deactivated, the force competing against the initial set load F3 of thespring 88 is only the force F1−F2 due to the differential pressure Δp. On the other hand, the differential pressure Δp (i.e., F1−F2) cannot be sufficiently secured until the discharge flow amount increases to some degree. This leads to such an operation of maintaining a certain flow amount after achieving a relatively large discharge flow amount. Generating F4 by supplying power to thesolenoid 80 can bring about the same effect as changing the initial set load F3 of thespring 88 to a lower load. In other words, this configuration allows thecontrol valve 8 to be displaced and switch the flow passage with the relatively small differential pressure Δp (i.e., F1−F2). Therefore, this configuration leads to such an operation of maintaining a certain flow amount after achieving a relatively small discharge flow amount. In this manner, the present embodiment can control the discharge flow amount with use of a magnetic attractive force (the thrust force F4) generated by thesolenoid 80. The CVT control unit appropriately controls a line pressure of theCVT 10 according to running conditions such as the number of revolutions of the engine, an opening degree of an accelerator (an opening degree of a throttle valve), and a vehicle speed. According thereto, the CVT control unit supplies a current to thesolenoid 80 based on the number of revolutions of the engine, the opening degree of the accelerator, and the like to control the magnetic attractive force (the thrust force F4), thereby changing the discharge flow amount (the pump capacity) of thepump element 4. Thepump apparatus 1 may be configured to omit thesolenoid 80. - The present embodiment can also acquire each of functions and effects regarding the
venturi portion 50 similar to the first embodiment even for the variable displacement pump. - Having described the pump apparatus according to the present invention based on the embodiments thereof, the specific configuration of the present invention is not limited to the embodiments, and the present invention also includes a design modification and the like thereof made within a range that does not depart from the spirit of the present invention. For example, the stepless transmission to which the pump apparatus supplies the hydraulic fluid is not limited to the CVT, and may be, for example, a toroidal-type transmission. The automatic transmission to which the pump apparatus supplies the hydraulic fluid is not limited to the stepless transmission, and may be a stepped transmission. The apparatus mounted on the vehicle to which the pump apparatus supplies the hydraulic fluid is not limited to the automatic transmission, and may be a power steering apparatus or the like. Further, the configurations of the individual embodiments can also be arbitrarily combined to each other or one another.
- The present application claims priority to Japanese Patent Application No. 2015-004311 filed on Jan. 13, 2015. The entire disclosure of Japanese Patent Application 2015-004311 filed on Jan. 13, 2015 including the specification, the claims, the drawings, and the abstract is incorporated herein by reference in its entirety.
- 1 pump apparatus
- 10 CVT (automatic transmission)
- 2 pump housing
- 20 pump housing main body
- 21 venturi forming block
- 213 communication hole (opening)
- 230 intake port
- 231 discharge port
- 4 pump element
- 40 driving shaft
- 400 pump chamber
- 41 rotor
- 410 slit
- 42 vane
- 43 cam ring
- 5 discharge passage
- 50 venturi portion
- 51 small diameter portion
- 52 inner diameter gradually-increasing portion
- 520 front portion
- 521 rear portion
- 53 large diameter portion
- 61 first fluid pressure chamber
- 71 second fluid pressure chamber
- 8 control valve
- 86 high pressure chamber
- 87 intermediate pressure chamber
Claims (19)
1. An automatic transmission pump apparatus for supplying hydraulic fluid to an automatic transmission of a vehicle, the automatic transmission pump apparatus comprising:
a pump housing including a pump element containing portion;
a driving shaft pivotally supported on the pump housing;
a pump element provided in the pump element containing portion and configured to be rotationally driven by the driving shaft, the pump element forming a plurality of pump chambers around the driving shaft;
an intake port formed at the pump housing and opened to an intake region where a volume of a pump chamber increases according to a rotation of the driving shaft among the plurality of pump chambers;
a discharge port formed at the pump housing and opened to a discharge region where the volume of the pump chamber reduces according to the rotation of the driving shaft among the plurality of pump chambers;
a discharge passage connected to the discharge port; and
a venturi portion provided on the way along the discharge passage, the venturi portion including a small diameter portion having a smaller inner diameter than an inner diameter of the discharge passage from the discharge port to the venturi portion and an inner diameter gradually-increasing portion formed in such a manner that an inner diameter thereof gradually increases from the small diameter portion toward a downstream side of the discharge passage; and
a control valve configured to receive introduction of hydraulic fluid on an upstream side of the venturi portion and hydraulic fluid in the venturi portion, the control valve including a spool valve body controlled based on a differential pressure between the hydraulic fluid on the upstream side of the venturi portion and the hydraulic fluid in the venturi portion, the control valve being configured to control a flow amount of the hydraulic fluid to be supplied into the automatic transmission at least by switching a flow passage of the hydraulic fluid introduced from the upstream side of the venturi portion.
2. The automatic transmission pump apparatus according to claim 1 , wherein the pump housing includes a pump housing main body including the pump element containing portion, and a venturi forming block that is a separate member from the pump housing main body and is joined to the pump housing main body,
wherein the venturi portion is formed at the venturi forming block, and
wherein the venturi forming block is jointed to the pump housing main body after the venturi portion is formed.
3. The automatic transmission pump apparatus according to claim 2 , wherein the pump housing main body is made from a metallic material,
wherein the venturi forming block is made from a resin material, and
wherein the venturi portion is formed by molding.
4. The automatic transmission pump apparatus according to claim 2 , wherein the pump housing main body is made from a metallic material,
wherein the venturi forming block is made from a sintered material, and
wherein the venturi portion is formed with use of a mold in a powder compacting process.
5. The automatic transmission pump apparatus according to claim 2 , wherein the small diameter portion of the venturi portion is formed so as to be opened on an outer surface of the venturi forming block.
6. The automatic transmission pump apparatus according to claim 1 , wherein the venturi portion is provided in such a manner that a longitudinal direction of the venturi portion and a direction of a, rotational axis of the driving shaft extend generally perpendicularly to each other.
7. The automatic transmission pump apparatus according to claim 6 , wherein the venturi portion is provided at a position that does not overlap the intake port on a cross section perpendicular to the rotational axis of the driving shaft but overlaps the intake port in the direction of the rotational axis of the driving shaft.
8. The automatic transmission pump apparatus according to claim 6 , wherein the venturi portion is provided in such a manner that a longitudinal direction of the venturi portion and a longitudinal direction of the control valve extend generally in parallel with each other.
9. The automatic transmission pump apparatus according to claim 8 , wherein the control valve includes a high pressure chamber into which a pressure on the upstream side of the venturi portion is introduced and an intermediate pressure chamber into which a pressure in the venturi portion is introduced, and
wherein the venturi portion is disposed in such a manner that the upstream side of the venturi portion faces the high pressure chamber of the control valve.
10. The automatic transmission pump apparatus according to claim 1 , wherein the venturi portion is provided in such a manner that a longitudinal direction of the venturi portion and a direction of a rotational axis of the driving shaft extend generally in parallel with each other.
11. The automatic transmission pump apparatus according to claim 10 , wherein the venturi portion is provided at a position that is located on a radially outer side with respect to the pump element containing portion in a radial direction of the rotational axis of the driving shaft, and overlaps the pump element containing portion in the direction of the rotational axis of the driving shaft.
12. The automatic transmission pump apparatus according to claim 1 , wherein the venturi portion includes an opening provided on the small diameter portion or one side of the inner diameter gradually-increasing portion that is closer to the small diameter portion in a longitudinal direction of the venturi portion, the opening being configured to supply the hydraulic fluid in the venturi portion into the control valve, and
wherein the opening includes a plurality of openings provided in a direction around an axis line along the longitudinal direction of the venturi portion.
13. The automatic transmission pump apparatus according to claim 1 , wherein the venturi portion is formed in such a manner that a narrower angle sandwiched between inner walls of the inner diameter gradually-increasing portion is 60 degrees or smaller.
14. The automatic transmission pump apparatus according to claim 13 , wherein, when it is defined that L represents a length of a longitudinal direction of the inner diameter gradually-increasing portion when the inner diameter gradually-increasing portion is formed as far as an inner diameter thereof reaches a same diameter as an inner diameter of the discharge passage from the discharge port to the venturi portion while the narrower angle sandwiched between inner walls of the inner diameter gradually-increasing portion is kept constant, the inner diameter gradually-increasing portion includes a front portion formed as far as a position where the length in the longitudinal direction is 65% of the length L or longer while the narrower angle sandwiched between the inner walls of the inner diameter gradually-increasing portion is kept constant at 60 degrees or smaller, and a rear portion provided on a downstream side of the front portion and formed in such a manner that the narrower angle exceeds 60 degrees.
15. The automatic transmission pump apparatus according to claim 1 , wherein the control valve or the venturi portion is provided at a housing that is a separate member from the pump housing.
16. The automatic transmission pump apparatus according to claim 1 , wherein the venturi portion includes an opening provided at the small diameter portion and configured to supply the hydraulic fluid in the venturi portion to the control valve.
17. The automatic transmission pump apparatus according to claim 1 , wherein the pump element is a pump element for a fixed displacement pump in which a discharge amount per rotation of the driving shaft is constant, and
wherein the control valve switches the flow passage of the hydraulic fluid so as to return the hydraulic fluid introduced from the upstream side of the venturi portion to an intake port side.
18. The automatic transmission pump apparatus according to claim 1 , wherein the pump element includes
a rotor including a plurality of slits in a circumferential direction,
a vane provided so as to be projectable and retractable from and into each of the slits of the rotor,
a cam ring provided displaceably in the pump element containing portion and annularly formed, the cam ring forming the plurality of pump chambers together with the rotor and the vane, and
a first fluid pressure chamber and a second fluid pressure chamber that are a pair of spaces formed between the cam ring and the pump element containing portion, the first fluid pressure chamber and the second fluid pressure chamber being respectively provided on one side where a volume reduces and an opposite side where the volume increases when an eccentric amount of the cam ring with respect to the rotor increases,
wherein the pump element is a pump element of a variable displacement pump in which a discharge amount per rotation of the driving shaft is variably controlled, and
wherein the control valve switches the flow passage of the hydraulic fluid so as to introduce the hydraulic fluid introduced from the upstream side of the venturi portion into the first fluid pressure chamber.
19. A pump apparatus comprising:
a pump housing including a pump element containing portion;
a driving shaft pivotally supported on the pump housing;
a pump element provided in the pump element containing portion and configured to be rotationally driven by the driving shaft, the pump element forming a plurality of pump chambers around the driving shaft;
an intake port formed at the pump housing and opened to an intake region where a volume of a pump chamber increases according to a rotation of the driving shaft among the plurality of pump chambers;
a discharge port formed at the pump housing and opened to a discharge region where the volume of the pump chamber reduces according to the rotation of the driving shaft among the plurality of pump chambers;
a discharge passage connected to the discharge port; and
a venturi portion provided on the way along the discharge passage, the venturi portion including a small diameter portion having a smaller inner diameter than an inner diameter of the discharge passage from the discharge port to the venturi portion and an inner diameter gradually-increasing portion formed in such a manner that an inner diameter thereof gradually increases from the small diameter portion toward a downstream side of the discharge passage; and
a control valve configured to receive introduction of hydraulic fluid on an upstream side of the venturi portion and hydraulic fluid in the small diameter portion, the control valve including a spool valve body controlled based on a differential pressure between the hydraulic fluid on the upstream side of the venturi portion and the hydraulic fluid in the small diameter portion, the control valve being configured to control a flow amount of the hydraulic fluid to be supplied into an apparatus mounted on a vehicle at least by switching a flow passage of the hydraulic fluid introduced from the upstream side of the venturi portion.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2015-004311 | 2015-01-13 | ||
JP2015004311A JP2016130462A (en) | 2015-01-13 | 2015-01-13 | Automatic transmission pump device or pump device |
PCT/JP2015/085738 WO2016114076A1 (en) | 2015-01-13 | 2015-12-22 | Pump device for use in automatic transmission, or pump device |
Publications (1)
Publication Number | Publication Date |
---|---|
US20180023563A1 true US20180023563A1 (en) | 2018-01-25 |
Family
ID=56405631
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US15/540,868 Abandoned US20180023563A1 (en) | 2015-01-13 | 2015-12-22 | Automatic transmission pump apparatus or pump apparatus |
Country Status (5)
Country | Link |
---|---|
US (1) | US20180023563A1 (en) |
JP (1) | JP2016130462A (en) |
CN (1) | CN107110155A (en) |
DE (1) | DE112015005940T5 (en) |
WO (1) | WO2016114076A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20180306185A1 (en) * | 2017-04-19 | 2018-10-25 | Zf Friedrichshafen Ag | Transmission |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN110131162B (en) * | 2019-06-29 | 2024-04-09 | 台州弘一液压伺服科技有限公司 | Energy-saving vane pump |
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2015
- 2015-01-13 JP JP2015004311A patent/JP2016130462A/en active Pending
- 2015-12-22 WO PCT/JP2015/085738 patent/WO2016114076A1/en active Application Filing
- 2015-12-22 CN CN201580071328.5A patent/CN107110155A/en active Pending
- 2015-12-22 US US15/540,868 patent/US20180023563A1/en not_active Abandoned
- 2015-12-22 DE DE112015005940.7T patent/DE112015005940T5/en not_active Withdrawn
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US2592884A (en) * | 1947-02-21 | 1952-04-15 | Hobart Mfg Co | Dishwasher |
US5098259A (en) * | 1989-08-29 | 1992-03-24 | Atsugi Unista Corporation | Fluid pump unit with flow control valve |
US5518380A (en) * | 1994-02-28 | 1996-05-21 | Jidosha Kiki Co., Ltd. | Variable displacement pump having a changeover value for a pressure chamber |
US6623154B1 (en) * | 2000-04-12 | 2003-09-23 | Premier Wastewater International, Inc. | Differential injector |
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US20180306185A1 (en) * | 2017-04-19 | 2018-10-25 | Zf Friedrichshafen Ag | Transmission |
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Also Published As
Publication number | Publication date |
---|---|
CN107110155A (en) | 2017-08-29 |
JP2016130462A (en) | 2016-07-21 |
DE112015005940T5 (en) | 2017-10-19 |
WO2016114076A1 (en) | 2016-07-21 |
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