WO2016114076A1

WO2016114076A1 - Pump device for use in automatic transmission, or pump device

Info

Publication number: WO2016114076A1
Application number: PCT/JP2015/085738
Authority: WO
Inventors: 悟多熊坂
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2015-01-13
Filing date: 2015-12-22
Publication date: 2016-07-21
Also published as: CN107110155A; JP2016130462A; US20180023563A1; DE112015005940T5

Abstract

Provided is a pump device capable of minimizing a decline in pump efficiency. A pump device equipped with: a venturi section provided partway along a discharge channel, and having a small-diameter section having a smaller inner diameter than the inner diameter of the discharge channel from the discharge port to the venturi section, and a gradually increasing inner-diameter section formed in a manner such that the inner diameter thereof gradually increases from the small-diameter section toward the downstream side of the discharge channel; and a control valve to which the pressure inside the venturi section and on the upstream side of the venturi section is introduced, and which controls the flow of a working fluid supplied to an automatic transmission by switching the working fluid channel on the basis of the difference in the pressure inside the venturi section (50) and on the upstream side of the venturi section.

Description

Pump device or pump device for automatic transmission

The present invention relates to a pump device.

Conventionally, a pump device having a control valve is known. The control valve controls the flow rate of the hydraulic fluid that the pump device supplies to the device. For example, the pump device described in Patent Document 1 generates a differential pressure according to the flow rate to be discharged. The control valve controls the flow rate by switching the flow path of the hydraulic fluid based on the differential pressure.

JP 2010-14074 A

However, the conventional pump device uses an orifice to generate a differential pressure. For this reason, there existed a possibility that the efficiency of a pump might fall. The objective of this invention is providing the pump apparatus which can suppress the fall of the efficiency of a pump.

In order to achieve the above object, in one embodiment of the present invention, a venturi portion is provided in the middle of the discharge passage and the inner diameter gradually increases from the small diameter portion toward the downstream side of the discharge passage in order to generate a differential pressure. Have

Therefore, a decrease in pump efficiency can be suppressed.

The structure of the hydraulic system to which the pump apparatus of Example 1 is applied is shown. 1 shows an outline of a configuration of a pump device according to a first embodiment. The partial cross section which cut the pump housing of Example 1 with the plane orthogonal to the axial center of a drive shaft is shown. Fig. 4 shows a cross-sectional view taken along line AA in Fig. 3. It is the figure which looked at the venturi formation block of Example 1 from the axial direction one side. The upper part schematically shows the discharge passage in the vicinity of the venturi part of the first embodiment. The lower row shows changes in pressure associated with each part in the upper row. The upper stage schematically shows the discharge passage in the vicinity of the orifice of the comparative example. The lower row shows changes in pressure associated with each part in the upper row. It is a graph which shows the relationship between the flow volume of Example 1, and a differential pressure | voltage. Example 1 is indicated by a solid line, and a comparative example is indicated by an alternate long and short dash line. The relationship between the narrow angle of Example 1 and a pressure loss ratio is shown. The upper row schematically shows a discharge passage in which the large diameter portion is provided upstream of the venturi portion in the first embodiment. The lower row shows changes in pressure associated with each part in the upper row. The upper part schematically shows a discharge passage having a step part (rear part) on the downstream side of the inner diameter gradually increasing part in the first embodiment. The lower row shows changes in pressure associated with each part in the upper row. 11 shows the relationship between the ratio L / L0 of L to L0 in FIG. 11 and the pressure loss ratio. The cross section which cut the venturi formation block of Example 2 with the plane which passes along the axial center of a venturi part is shown. It is the figure which looked at the pump housing of Example 4 from the direction where the axial center of a drive shaft extends. FIG. 15 shows a cross section taken along the line BB of FIG. The outline of the structure of the pump apparatus of Example 6 is shown. The partial cross section which cut the pump housing of Example 6 with the plane containing the axial center of a drive shaft is shown.

Hereinafter, modes for carrying out the pump device of the present invention will be described based on the embodiments shown in the drawings.

[Example 1]
First, the configuration will be described. FIG. 1 shows a configuration of a hydraulic system to which the pump device 1 is applied. The pump device 1 is mounted on an automobile vehicle. The pump device 1 is a hydraulic fluid supply source that supplies hydraulic fluid to other devices (vehicle mounted devices) mounted on the vehicle. The vehicle-mounted device to which the pump device 1 supplies hydraulic fluid is an automatic transmission. The automatic transmission is a continuously variable transmission, specifically a belt-type continuously variable transmission (hereinafter referred to as CVT) 10. The hydraulic fluid is ATF (Automatic Transmission Fluid). The pump device 1 is driven by an internal combustion engine as a prime mover, and sucks and discharges hydraulic fluid from the oil pan 100. For example, a CVT10 oil pan 100 can be used. Various valves controlled by the CVT control unit are provided in the control valve of the CVT10. The hydraulic fluid discharged from the pump device 1 is supplied to each part (primary pulley, secondary pulley, forward clutch, reverse brake, torque converter, lubrication / cooling system, etc.) of the CVT 10 via the control valve.

The pump device 1 has a pump housing 2, a pump element 4, a venturi part 50, and a control valve 8. The pump housing 2 houses the pump element 4, the control valve 8, and the venturi part 50. The pump housing 2 is provided with a suction passage 3, a discharge passage 5, a high pressure passage 6, an intermediate pressure passage 7, and a return passage 9 as passages through which hydraulic fluid flows. The suction passage 3 connects the oil pan 100 and the pump element 4. The discharge passage 5 connects the pump element 4 and the CVT 10. A venturi 50 is provided on the discharge passage 5. The venturi section 50 is a throttle section provided in the middle of the discharge passage 5. The high-pressure passage 6 connects the control valve 8 to the pump element 4 side (hereinafter referred to as the upstream side) with respect to the venturi section 50 in the discharge passage 5. The intermediate pressure passage 7 connects the venturi unit 50 and the control valve 8. The return passage 9 connects the control valve 8 and the suction passage 3 (oil pan 100). A drive shaft 40 is pivotally supported on the pump housing 2. The drive shaft 40 is driven by a crankshaft of the internal combustion engine. The pump element 4 is rotationally driven by a drive shaft 40. The pump element 4 sucks hydraulic fluid from the oil pan 100 through the suction passage 3. The pump element 4 discharges hydraulic fluid to the discharge passage 5 and supplies it to the CVT 10 via the discharge passage 5. A relatively high pressure (hereinafter referred to as “high pressure”) upstream of the venturi section 50 is introduced into the control valve 8 via the high pressure passage 6. A relatively low pressure (medium pressure, hereinafter referred to as intermediate pressure) in the venturi section 50 is introduced into the control valve 8 through the intermediate pressure passage 7. The control valve 8 switches the flow path of the hydraulic fluid based on the difference (differential pressure) between the pressure upstream of the venturi unit 50 and the pressure in the venturi unit 50. Thereby, the flow volume of the hydraulic fluid which the pump element 4 supplies to CVT10 is controlled.

FIG. 2 shows an outline of the configuration of the pump device 1. The cross section which cut the pump element 4 of the state taken out from the pump housing 2 with the plane orthogonal to the axial center (rotating shaft) O of the drive shaft 40 is shown. The partial cross section which cut | disconnected the control valve 8 by the plane which passes along the axial center is shown. Each passage 3 and the like are schematically drawn. The direction in which the hydraulic fluid flows is indicated by a dashed line arrow. FIG. 3 shows a partial cross section of the pump housing 2 taken along a plane orthogonal to the axis O. FIG. 4 shows a cross section taken along line AA of FIG. Hereinafter, for convenience of explanation, an orthogonal coordinate system is set. The x axis is provided in the left-right direction in FIG. 3, and the right side is positive. The y-axis is provided in the vertical direction in the plane of FIG. 3, and the upper side is positive. The z axis is provided in a direction perpendicular to the paper surface of FIG. 3, and the front side of the paper surface is positive. The drive shaft 40 (axial center O) extends in the z-axis direction. The pump housing 2 has a pump housing body 20 and a venturi forming block 21. The pump housing body 20 is made of a metal material. In addition to the passages 3 and the like, a suction port 230 and a discharge port 231 are formed in the pump housing body 20. The venturi forming block 21 is formed of a resin material. The venturi forming block 21 is a member different from the pump housing body 20.

The pump housing body 20 has a rear body 22, a side plate 23, and a front body. The rear body 22 includes an accommodation recess 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 accommodation hole 227, and a venturi forming block accommodation hole 228. , And a bearing holding hole is formed. The housing recess 220 has a bottomed cylindrical shape. The housing recess 220 extends in the z-axis direction and opens on the z-axis positive direction side of the rear body 22. A semi-cylindrical first groove (not shown) and a second groove (not shown) are provided on the inner peripheral surface of the housing recess 220 so as to extend in the z-axis direction. The second groove is provided on the opposite side of the first groove with the axis of the housing recess 220 interposed therebetween. The bearing holding hole (not shown) has a bottomed cylindrical shape. The bearing holding hole extends in the z-axis direction and opens at the bottom of the housing recess 220 on the z-axis negative direction side. A bearing is installed on the inner periphery of the bearing holding hole. The end of the drive shaft 40 in the negative z-axis direction is inserted on the inner peripheral side of the bearing, and is rotatably installed. The discharge pressure chamber 226 is a bottomed recess provided at the bottom of the housing recess 220 and opens to the bottom.

The first hole 221 extends in the y-axis direction on the x-axis negative direction side and the z-axis negative direction side of the rear body 22. The opening of the first hole 221 on the y-axis negative direction side of the rear body 22 is sealed with a plug member 221a. The first hole 221 is formed so as to partially overlap the discharge pressure chamber 226 when viewed from the y-axis direction and the z-axis direction, and is connected to the discharge pressure chamber 226. The valve housing hole 227 is substantially cylindrical, and extends in the x-axis direction on the y-axis positive direction side and the z-axis negative direction side of the rear body 22. That is, the longitudinal direction (x-axis direction) of the valve housing hole 227 is orthogonal to the direction of the axis O (z-axis direction). The x-axis positive direction end of the valve housing hole 227 opens to the outer surface of the rear body 22. This opening is sealed by a plug member 227a. The x-axis negative direction end of the valve housing hole 227 is connected to the y-axis positive direction end of the first hole 221. One end of the fifth hole 225 opens near the valve housing hole 227 in the negative x-axis direction. The other end of the fifth hole 225 opens to the outer surface of the rear body 22.

The venturi forming block accommodation hole 228 is substantially cylindrical, and extends in the x-axis direction on the negative side of the rear body 22 in the z-axis direction. That is, the longitudinal direction (x-axis direction) of the venturi forming block accommodation hole 228 is substantially parallel to the longitudinal direction of the valve accommodation hole 227 and is orthogonal to the direction of the axis O (z-axis direction). The x-axis negative direction side of the venturi forming block accommodation hole 228 is formed so as to intersect the first hole 221 and is connected to the first hole 221. Further, the x-axis negative direction side of the venturi forming block accommodating hole 228 is formed so as to partially overlap the discharge pressure chamber 226 when viewed from the y-axis direction and the z-axis direction, and is connected to the discharge pressure chamber 226. The x-axis negative direction end of the venturi forming block accommodation hole 228 opens to the outer surface of the rear body 22. This opening is sealed by a plug member 228a. The second hole 222 is provided on substantially the same axis as the venturi forming block accommodating hole 228, and extends in the x-axis direction on the x-axis positive direction side and the z-axis negative direction side of the rear body 22. The x-axis negative direction end of the second hole 222 is connected to the x-axis positive direction end of the venturi forming block accommodation hole 228. The inner diameter of the second hole 222 is smaller than the inner diameter of the venturi forming block accommodation hole 228. The third hole 223 extends in the z-axis direction on the x-axis positive direction side and the z-axis negative direction side of the rear body 22. The z-axis positive direction end of the third hole 223 is connected to the x-axis positive direction end of the second hole 222. The z-axis negative direction end of the third hole 223 opens to the outer surface of the rear body 22. The fourth hole 224 connects the x-axis positive direction side of the valve accommodation hole 227 and the x-axis positive direction side of the venturi forming block accommodation hole 228.

The side plate 23 has a disk shape. The side plate 23 is provided with a shaft receiving hole (not shown). The shaft accommodating hole passes through the center portion of the side plate 23. A pair of

suction ports

230a and 230b and a pair of

discharge ports

231a and 231b are provided on the surface of one side of the side plate 23 in the axial direction. The pair of

suction ports

230a and 230b are grooves extending in a substantially arc shape around the shaft housing hole (hereinafter referred to as a circumferential direction), and are provided at positions facing each other across the shaft housing hole. The pair of

discharge ports

231a and 231b are grooves extending in a substantially arc shape in the circumferential direction, and are provided at positions facing each other across the shaft housing hole. The suction port 230 and the discharge port 231 are alternately arranged in the circumferential direction. The side plate 23 is provided with a communication path (not shown). The communication passage penetrates the side plate 23 in the axial direction and communicates both side surfaces thereof. The first communication path opens to the suction port 230. The second communication path opens at the discharge port 231. The side plate 23 is installed in the housing recess 220 of the rear body 22. The one surface of the side plate 23 faces the opening side (z-axis positive direction side) of the housing recess 220. The other side surface of the side plate 23 faces the bottom of the housing recess 220. The shaft receiving 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 is connected to the suction passage 3 of the rear body 22. Each suction port 230 is connected to the suction passage 3 via the first communication passage. The second communication path of the side plate 23 is connected to the discharge pressure chamber 226 of the rear body 22. Each discharge port 231 is connected to the discharge pressure chamber 226 via the second communication path.

The front body (not shown) 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 seal the housing recess 220. The front body 24 is provided with a bearing holding hole. The bearing holding hole extends in the z-axis direction. A bearing is installed on the inner periphery of the bearing holding hole. A z-axis positive direction end portion of the drive shaft 40 is inserted on the inner peripheral side of the bearing, and is rotatably installed.

The venturi forming block 21 is substantially cylindrical. The diameter (outer diameter) of the outer peripheral surface of the venturi forming block 21 is substantially equal to the diameter (inner diameter) of the inner peripheral surface of the venturi forming block accommodation hole 228. A venturi portion 50 is formed in the venturi forming block 21. The venturi portion 50 is a throttle portion formed on the venturi forming block 21 by molding. The venturi forming block 21 is joined to the pump housing body 20 after the venturi portion 50 is formed. 3 and 4, a cross section of the venturi forming block 21 taken along a plane passing through an axis (axial center) along the longitudinal direction of the venturi 50 is shown. FIG. 5 is a view of the venturi forming block 21 as seen from the direction in which the axis of the venturi portion 50 extends (from the x-axis negative direction side). Hereinafter, the direction in which the axis of the venturi 50 extends is referred to as the axial direction, and the direction around the axis is referred to as the circumferential direction. The venturi forming block 21 includes an inner diameter gradually decreasing portion 210, a venturi portion 50, a communication hole 213, a first communication groove 214, and a second communication groove 215. The venturi part 50 has a small diameter part 51 and an inner diameter gradually increasing part 52.

The inner diameter gradually decreasing portion 210 is provided on the inner peripheral side of the venturi forming block 21 so as to extend in the axial direction, and opens to the end surface on one side of the venturi forming block 21 in the axial direction. The inner diameter gradually decreasing portion 210 is a tapered portion that tapers from one side in the axial direction toward the other side in the axial direction (downstream of the discharge passage 5), and is formed so that the inner diameter gradually decreases toward the other side in the axial direction. Has been. The inner diameter of one end in the axial direction of the inner diameter gradually decreasing portion 210 is smaller than the inner diameter of the venturi forming block accommodation 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. One end in the axial direction of the small diameter portion 51 is connected to the other end in the axial direction of the inner diameter gradually decreasing portion 210. The inner diameter of the small diameter portion 51 is substantially equal to the inner diameter of the other end in the axial direction of the inner diameter gradually decreasing portion 210 and is constant in the axial direction.

The inner diameter gradually increasing portion 52 is provided on the inner peripheral side of the venturi forming block 21 so as to extend in the axial direction. One end in the axial direction of the inner diameter gradually increasing portion 52 is connected to the other end in the axial direction of the small diameter portion 51, and the other end in the axial direction of the inner diameter gradually increasing portion 52 is open to the end surface on the other axial side of the venturi forming block 21. The gradually increasing inner diameter portion 52 is a tapered portion that tapers from the other side in the axial direction toward one side in the axial direction (upstream side of the discharge passage 5), and from one side in the axial direction to the other side in the axial direction (downstream side of the discharge passage 5). ) So that the inner diameter gradually increases. The inner diameter of the other end in the axial direction of the inner diameter gradually increasing portion 52 is slightly smaller than the inner diameter of the second hole 222. The venturi forming block 21 has a narrow angle θ sandwiched between the inner walls of the inner diameter gradually increasing portion 52 (the angle between the inner walls viewed from the direction orthogonal to the axis of the venturi portion 50 is 180 degrees or less). It is formed so as to be less than 15 degrees, specifically about 15 degrees.

The communication hole 213 is a radial hole formed inside the venturi forming block 21 and extending in the radial direction of the venturi forming block 21. A plurality (four) of communication holes 213 are provided and are arranged at substantially equal intervals in the circumferential direction. The communication hole 213 is provided at a position overlapping the small diameter portion 51 in the axial direction. The radially inner end of the communication hole 213 opens to the small diameter portion 51. The first communication groove 214 is a circumferential groove formed on the 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 radially outer end of the communication hole 213 opens in the first communication groove 214 (the bottom thereof). 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. One axial end of the second communication groove 215 is connected to the first communication groove 214. The other end in the axial direction of the second communication groove 215 is located in the vicinity of the end surface on the other axial side of the venturi forming block 21.

The venturi forming block 21 is joined to the pump housing body 20 (the venturi forming block accommodation hole 228 of the rear body 22) as shown in FIGS. 3 and 4 after the venturi portion 50 is formed. The axis of the venturi forming block 21 (the venturi portion 50) extends in the x-axis direction. The one axial side of the venturi forming block 21 is the x-axis negative direction side, and the other axial side of the venturi forming block 21 is the x-axis positive direction side. The end surface on the other axial side of the venturi forming block 21 (where the inner diameter gradually increasing portion 52 opens) abuts on the end surface on the positive x-axis side of the venturi forming block accommodation hole 228 (where the second hole 222 opens). The other axial end of the second communication groove 215 in the venturi forming block 21 is connected to the opening of the fourth hole 224 in the venturi forming block accommodation hole 228. Note that, on the outer peripheral surface of the venturi forming block 21, a third communication extending in the circumferential direction and connected to the other axial end of the second communication groove 215 at an axial position opposed to the opening of the fourth hole 224 in the radial direction. A groove may be provided. In this case, since the other end in the axial direction of the second communication groove 215 and the opening of the fourth hole 224 are connected via the third communication groove, the venturi formation block 21 around the axis of the venturi formation block accommodation hole 228 is connected. There is no need to adjust the position of the rotation direction.

The pump element 4 is housed in a space surrounded by the inner periphery of the housing recess 220 in the rear body 22, the surface on the z-axis positive direction side of the side plate 23, and the surface on the z-axis negative direction side of the front body. That is, the space functions as a pump element housing portion. A drive shaft 40 is installed in the space, and the pump element 4 forms a plurality of pump chambers 400 around the drive shaft 40. As shown in FIG. 2, the pump element 4 is a vane pump type and has a set of a rotor 41 and a vane 42. The rotor 41 is provided in the pump element accommodating portion and is connected to the drive shaft 40 by serration. The rotor 41 is rotationally driven by the drive shaft 40 and rotates as the drive shaft 40 rotates. The rotor 41 is provided with a plurality of (ten) slits 410 (grooves extending in the radial direction) radially. The slit 410 opens on the outer peripheral surface of the rotor 41. The plurality of slits 410 are provided at substantially equal intervals in the circumferential direction of the rotor 41. A vane 42 is installed in each slit 410. The vane 42 is a substantially rectangular plate member (blade). The vane 42 is provided so as to be able to come out of the slit 410 or to enter the inside of the slit 410 (can be moved in and out).

The cam ring 43 has an annular shape. The outer periphery of the cam ring 43 is fitted to the inner periphery of the housing recess 220. The center (axial center) of the cam ring 43 substantially coincides with the axial center O. The inner peripheral surface of the cam ring 43 has a cylindrical shape extending in the z-axis direction, and is substantially elliptical when viewed from the z-axis direction. A semi-cylindrical first groove portion 431 and a second groove portion 432 are provided on the outer peripheral surface of the cam ring 43. The second groove portion 432 is provided on the opposite side of the first groove portion 431 across the axis O of the cam ring 43. A first pin 451 is fitted and installed between the first groove portion of the housing recess 220 and the first groove portion 431 of the cam ring 43. A second pin 452 is fitted and installed between the second groove portion of the housing recess 220 and the second groove portion 432 of the cam ring 43. The

pins

451 and 452 are fixed to the pump housing body 20. The

pins

451 and 452 suppress the rotation of the cam ring 43 with respect to the pump housing 2. The cam ring 43 is disposed so as to surround the rotor 41 in the pump element housing portion. The cam ring 43 forms a plurality of pump chambers 400 together with the rotor 41 and the vanes 42. That is, the side plate 23 and the front body 24 are disposed on the axial side surfaces of the cam ring 43 and the rotor 41. The space between the inner peripheral surface of the cam ring 43 and the outer peripheral surface of the rotor 41 is sealed on both sides in the axial direction by the side plate 23 and the front body 24, while a plurality of (10 pieces) are provided by the plural vanes 42. It is divided into a pump chamber (volume chamber) 400.

For convenience of explanation, as shown in FIG. 2, the X axis is taken in the major axis direction and the Y axis is taken in the minor axis direction of the inner peripheral surface of the cam ring 43 which is substantially elliptical. The rotor 41 rotates counterclockwise in FIG. The radial distance between the outer peripheral surface of the rotor 41 and the inner peripheral surface of the cam ring 43 as it goes from the axial center O of the cam ring 43 toward the negative X-axis direction and from the axial center O toward the positive X-axis direction. (The radial dimension of the pump chamber 400) increases. As the distance changes, the vanes 42 appear and disappear from the slits 410 to separate the pump chambers 400. The volume of the pump chamber 400 increases as it goes from the axis O toward the X axis negative direction side and from the axis O toward the X axis positive direction side. Due to the difference in volume of the pump chamber 400, the rotor 41 rotates on the Y axis positive direction side with respect to the axis O (the pump chamber 400 moves toward the X axis negative direction side). While the volume of the pump chamber 400 decreases on the side, the volume of the pump chamber 400 increases on the X axis negative direction side from the axis O. As the rotor 41 rotates on the Y axis negative direction side of the axis O (the pump chamber 400 moves toward the X axis positive direction side), the volume of the pump chamber 400 decreases on the X axis negative direction side of the axis O. On the other hand, the volume of the pump chamber 400 increases on the X axis positive direction side from the axis O.

Thus, the pump chamber 400 periodically expands and contracts while rotating around the axis O in the counterclockwise direction. The suction port 230 opens in a region on the X axis negative direction side and the Y axis positive direction side, and a region on the X axis positive direction side and the Y axis negative direction side. That is, the volume of the pump chamber 400 increases with the rotation of the drive shaft 40 in the suction port 230 (in other words, the pump chamber 400 whose volume increases with the rotation of the drive shaft 40 among the plurality of pump chambers 400 is positioned. Open) in the inhalation area. The discharge port 231 opens in a region on the X axis positive direction side and the Y axis positive direction side, and a region on the X axis negative direction side and the Y axis negative direction side. That is, the volume of the pump chamber 400 decreases with the rotation of the drive shaft 40 in the discharge port 231 (in other words, the pump chamber 400 whose volume decreases with the rotation of the drive shaft 40 among the plurality of pump chambers 400 is positioned. Open) in the discharge area. The pump chamber 400 sucks the working fluid from the suction port 230 in the suction region, and discharges the above-mentioned sucked working fluid to the discharge port 231 in the discharge region. Corresponding to the pair of

suction ports

230a and 230b and the pair of

discharge ports

231a and 231b, suction and discharge are performed twice per rotation of the drive shaft 40, respectively. The hydraulic fluid at both outlets 231 is collected in one place. The cam ring 43 is provided so as not to move within the pump element housing. That is, the pump element 4 is a fixed capacity type in which the discharge amount per one rotation of the drive shaft 40 (hereinafter referred to as pump capacity) is constant. The pump element 4 may be a trochoid pump type inner rotor or outer rotor set, or other pump type.

The control valve 8 is a spool valve body and is accommodated in the valve accommodation hole 227. The control valve 8 can be displaced (stroked) in the x-axis direction within the valve housing 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 recess 85. The

land portions

81 and 82 are columnar and have substantially the same diameter. The diameter of the outer peripheral surface of each

land portion

81, 82 is slightly smaller than the diameter of the inner peripheral surface of the valve housing hole 227. In the control valve 8, the first land portion 81 is provided on the x-axis negative direction side, and the second land portion 82 is provided on the x-axis positive direction side end. A circumferential groove 810 extending in the direction around the axis of the control valve 8 (hereinafter referred to as the circumferential direction) is provided on the outer peripheral surface of the first land portion 81. A plurality of circumferential grooves 820 extending in the circumferential direction are provided on the outer peripheral surface of the second land portion 82. The connecting portion 83 has a cylindrical shape extending between the

land portions

81 and 82 and extending in the x-axis direction. The diameter of the outer peripheral surface of the connecting portion 83 is smaller than the

land portions

81 and 82. The spacer portion 84 has a rod shape extending from the first land portion 81 toward the negative x-axis direction. The recess 85 has a bottomed cylindrical shape, and extends inside the second land portion 82 in the x-axis direction. The recess 85 opens at the end surface of the second land portion 82 in the positive x-axis direction.

Inside the valve housing hole 227, a high pressure chamber 86 is defined by being surrounded by the end surface of the first land 81 in the negative x-axis direction and the inner peripheral surface of the valve housing hole 227. An intermediate pressure chamber 88 is defined by being surrounded by the x-axis positive direction end surface of the second land portion 82, the inner peripheral surface of the valve housing hole 227, and the x-axis negative direction end surface of the plug member 227a. A drain chamber 89 is defined between the first land portion 81 and the second land portion 82 and on the outer periphery of the connection portion 83. A spring 88 is installed in the intermediate pressure chamber 88. The spring 88 is a coil spring. The positive end of the spring 88 in the x-axis direction is held by a plug member 227a. The x-axis negative direction side of the spring 88 is held inside the recess 85 of the control valve 8. The spring 88 is installed in a compressed state. The spring 88 is a return spring that constantly biases the control valve 8 toward the negative x-axis direction. The movement of the control valve 8 in the valve housing hole 227 in the x-axis negative direction side is restricted by the x-axis negative direction end of the spacer 84 coming into contact with the x-axis negative direction end surface of the valve housing hole 227. Regardless of the movement of the control valve 8 in the valve accommodating hole 227, the first hole 221 opens in the high pressure chamber 86 and the fourth hole 224 opens in the intermediate pressure chamber 88.

Next, the configuration of the plurality of passages 3 will be described. Each discharge port 231 of the side plate 23 communicates with the first hole 221 or the venturi forming block accommodation hole 228 via the discharge pressure chamber 226 of the rear body 22. A connecting portion between the discharge pressure chamber 226 and the first hole 221 or the venturi forming block accommodating hole 228, the x axis negative direction side from the venturi forming block 21 (inner diameter gradually decreasing portion 210) in the venturi forming block accommodating hole 228, and an inner diameter gradually decreasing portion. 210 functions as a discharge passage 5 from the discharge port 231 (discharge pressure chamber 226) to the venturi portion 50 (small diameter portion 51 and gradually increasing inner diameter portion 52), in other words, the discharge passage 5 upstream of the venturi portion 50. The inner diameter of the small diameter portion 51 is formed smaller than the inner diameter of the discharge passage 5. The inner diameter gradually increasing portion 52 of the venturi portion 50 communicates with the outside of the rear body 22 through the second hole 222 and the third hole 223. The second hole 222 and the third hole 223 function as the discharge passage 5 from the venturi portion 50 toward the CVT 10, in other words, the discharge passage 5 on the downstream side of the venturi portion 50. The inner diameter of the discharge passage 5 is larger than the inner diameter of the inner diameter gradually increasing portion 52 at the x-axis positive direction end. The connection (intersection) part of the first hole 221 with the venturi forming block accommodation hole 228 and the connection part of the valve accommodation hole 227 branch from the discharge passage 5 upstream of the venturi part 50 and the control valve 8 It functions as a high-pressure passage 6 connected to the high-pressure chamber 86. The communication hole 213, the first communication groove 214, the second communication groove 215, and the fourth hole 224 of the rear body 22 of the venturi forming block 21 branch from the venturi section 50 (small diameter section 51) in the discharge passage 5 to control valves. 8 functions as an intermediate pressure passage 7 (venturi pressure introduction passage) connected to the intermediate pressure chamber 88. The communication hole 213 functions as a venturi pressure introducing hole. The fifth hole 225 in the rear body 22 functions as a return passage 9 from the drain chamber 89 of the control valve 8 toward the oil pan 100.

As shown in FIGS. 3 and 4, the longitudinal direction (x-axis direction) of the venturi portion 50 is substantially orthogonal to the direction (z-axis direction) in which the axis O of the drive shaft 40 extends, and the longitudinal direction of the control valve 8. It is substantially parallel to the direction (x-axis direction). The venturi unit 50 is disposed so that the upstream side thereof faces the high pressure chamber 86 of the control valve 8. In other words, the discharge passage 5 on the upstream side of the venturi section 50 and the high-pressure chamber 86 at least partially overlap in the x-axis direction. More specifically, the x-axis negative direction side of the venturi forming block accommodating hole 228 with respect to the x-axis negative direction side and the high-pressure chamber 86 (when the control valve 8 is most displaced to the x-axis negative direction side) are y It overlaps at least partially when viewed from the axial direction.

[Action]
Next, the function and effect will be described. The upper part of FIG. 6 schematically shows the discharge passage 5 in the vicinity of the venturi section 50. The arrow indicates the direction in which the hydraulic fluid flows. The flow rate of hydraulic fluid in the discharge passage 5 upstream from the venturi section 50 is u ₁ and the pressure is p ₁ . The flow velocity in the small diameter portion 51 is u ₂ and the pressure is p ₂ . The flow velocity in the discharge passage 5 downstream from the venturi 50 is u ₃ and the pressure is p ₃ . The lower part of FIG. 6 shows changes in the pressure p associated with each part in the upper part. The inner diameter (cross-sectional area) of the small-diameter portion 51 is smaller than the inner diameter (cross-sectional area) of the discharge passage 5 upstream from the venturi portion 50. Therefore, u ₂ increases from u ₁ . This increase in flow velocity is proportional to the flow rate and inversely proportional to the difference in cross-sectional area. According to Bernoulli's theorem, the pressure decreases in a quadratic function as the flow velocity increases. Thus, p ₂ is lower than p _1. This pressure drop corresponds to the increase in flow rate, that is, the flow rate. As described above, the venturi section 50 (small diameter section 51) as the throttle section generates a differential pressure Δp = p ₁ −p ₂ corresponding to the flow rate. In the venturi section 50, the inner diameter of the inner diameter gradually increasing section 52 gradually increases toward the downstream side. Therefore, the flow velocity of the inner diameter gradually increasing portion 52 gradually decreases toward the downstream side. Since the decrease in flow velocity is gradual, energy loss is not large. Therefore, the pressure in the inner diameter gradually increasing portion 52 gradually increases toward the downstream side in accordance with the decrease in the flow velocity. By extension from the venturi section 50 is an inner diameter of the downstream side of the venturi 50 to the vicinity of the inner diameter of the discharge passage 5 on the upstream side, the flow rate was reduced to the vicinity of u _1, the pressure is raised to the vicinity of the p ₁ (Recovery) . In this way, a large loss of energy is suppressed by gradually increasing the inner diameter of the downstream side (inner diameter gradually increasing portion 52) in the throttle portion. For this reason, on the downstream side of the throttle part, the flow velocity decreases to the same level as that upstream from the throttle part, and the pressure recovers to the same level as the upstream side from the throttle part.

The hydraulic fluid (p ₁ ) on the upstream side of the venturi section 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 (small diameter portion 51) is introduced into the intermediate pressure chamber 88 through the intermediate pressure passage 7. In addition, the drain chamber 89 is kept at a low pressure (same as the suction passage 3 and is opened to the atmospheric pressure). A force F1 in the positive x-axis direction due to p ₁ of the high-pressure chamber 86 and a force F2 in the negative x-axis direction due to p ₂ in the intermediate pressure chamber 88 act on the control valve 8. Further, the force F3 in the negative x-axis direction by the spring 88 acts on the control valve 8. When the difference F1-F2 between F1 and F2 (the force corresponding to the differential pressure Δp) exceeds F3, the control valve 8 moves to the x-axis positive direction side. Thus, when the high pressure chamber 86 and the return passage 9 communicate with each other, the hydraulic fluid introduced from the discharge passage 5 upstream of the venturi section 50 to the high pressure passage 6 (high pressure chamber 86) passes through the return passage 9 and the suction passage. 3 (suction port 230 side). That is, the control valve 8 switches the flow path so that the working fluid recirculates to the suction side based on the differential pressure Δp between the upstream side of the venturi portion 50 and the small diameter portion 51. When the working fluid returns to the suction side, the flow rate supplied to the CVT 10 via the discharge passage 5 is limited to a necessary amount. Thus, the venturi section 50, the high pressure passage 6, the intermediate pressure passage 7, the control valve 8, and the return passage 9 function as a control section that controls the discharge flow rate of the pump element 4.

In a conventional pump device, an orifice has been used as a means for generating a differential pressure. The orifice can be formed by a simple structure in which, for example, a thin plate throttle is provided in the flow path. A pressure difference corresponding to the flow rate is generated between upstream and downstream of the orifice. However, in the orifice, the flow is disturbed at the outlet of the restrictor, and the pressure downstream of the orifice is reduced by losing energy. The lost energy becomes heat or sound and diffuses to the outside. For this reason, the efficiency of a pump will fall. The greater the differential pressure, the lower the pump efficiency. Hereinafter, a pump device similar to the present embodiment using the orifice 500 instead of the venturi unit 50 is referred to as a comparative example. The narrow angle θ at the outlet of the orifice 500 is 120 to 180 degrees. FIG. 7 is a view similar to FIG. 6 in the comparative example. The upper stage shows the discharge passage 5 in the vicinity of the orifice 500. The flow rate of the hydraulic fluid in the discharge passage 5 upstream from the orifice 500 is u ₁ and the pressure is p ₁ . The flow velocity in the discharge passage 5 downstream from the orifice 500 is u ₂ and the pressure is p ₂ . The inner diameter of the orifice 500 is smaller than the inner diameter of the discharge passage 5 upstream of the orifice 500. Thus, the flow velocity at the orifice 500 increases above u _{1 and} the pressure at the orifice 500 decreases below p ₁ . The inner diameter of the outlet of the orifice 500 increases suddenly toward the downstream side. Therefore, a vortex is generated at the outlet of the orifice 500, and energy is greatly lost. Therefore, although u ₂ decreases to u ₁ , p ₂ does not increase (recover) to p ₁ . That is, the pressure decreases (pressure loss). The pressure p ₂ after such a decrease is supplied to the CVT 10.

On the other hand, in the pump device 1 of this embodiment, a venturi pipe is used instead of the orifice as means for generating the differential pressure. In the venturi section 50, a large loss of energy is suppressed by gently increasing the inner diameter of the downstream side (inner diameter gradually increasing section 52) in the throttle section. For this reason, the pressure recovers as the flow rate decreases. That is, pressure loss in the differential pressure generating means is suppressed. Therefore, it is possible to generate a differential pressure while suppressing a decrease in pump efficiency. In particular, since an automatic transmission such as a continuously variable transmission uses a larger flow rate than a power steering device or the like, a large pressure loss suppression effect can be obtained. In addition, at the entrance (upstream side of the small-diameter portion 51) of the throttle portion of the venturi portion 50, the diameter of the inner diameter gradually decreasing portion 210 is gradually reduced, so that it is possible to suppress the occurrence of turbulence in the flow. This increases the flow velocity and reduces the pressure without a significant loss of energy. Therefore, the pressure can be reduced more efficiently (the pressure loss as a whole is suppressed). Therefore, the efficiency of the pump can be further improved.

In the comparative example, if an attempt is made to reduce the energy loss at the orifice 500 in order to suppress a reduction in pump efficiency, the differential pressure Δp (corresponding force F1-F2) becomes small. When trying to operate the control valve 8 with a small Δp, the behavior of the control valve 8 becomes unstable. Thereby, the dispersion | variation in the discharge flow volume (henceforth a control flow volume) of the pump element 4 made into a control object will become large. On the other hand, in the present embodiment, the differential pressure (corresponding force F1-F2) can be increased while suppressing a decrease in the efficiency of the pump. Therefore, the above variation in the control flow rate can also be suppressed. FIG. 8 shows the difference between the discharge flow rate (flow rate passing through the differential pressure generating means) Q of the pump element 4 and the pressure acting on both axial sides of the control valve 8 (differential pressure generated by the differential pressure generating means) Δp. It is a graph which shows a relationship. When the pump efficiency (pressure loss at the differential pressure generating means) is the same in this embodiment and the comparative example, the characteristics of the present embodiment are indicated by a solid line, and the characteristics of the comparative example are indicated by an alternate long and short dash line. Δp changes in a quadratic curve according to Q. The operation (displacement) of the control valve 84 is controlled by Δp, in other words, by Q. The change rate of Δp with respect to Q is larger in the present example than in the comparative example. The Q required to generate the same Δp is less in this example than in the comparative example. That is, even with the same Q, this embodiment can generate a larger Δp (corresponding force F1-F2) than the comparative example. For this reason, the behavior of the control valve 8 can be stabilized and variations in the control flow rate can be suppressed.

In addition to F1 to F3, an external load (external force) may act on the control valve 8. In this case, the control flow rate may deviate from the original amount. For example, a relatively large amount of contamination is present in the hydraulic fluid under the usage environment of the automatic transmission (CVT10). If a load is generated in the control valve 8 due to contamination or the like in the gap between the outer peripheral surface of the control valve 8 and the inner peripheral surface of the valve housing hole 227, the control valve 8 becomes difficult to move, and the flow rate corresponding to this load Therefore, the control flow rate deviates from the original amount. On the other hand, in this embodiment, a small change in the flow rate Q can cause a large change in the differential pressure Δp (the corresponding force F1-F2). Therefore, the deviation of the control flow rate is reduced. In FIG. 8, a value obtained by converting the load into Δp is represented by δp, and a deviation of Q corresponding to δp is represented by δQ. That is, when a predetermined Q corresponds to an arbitrary Δp, if the arbitrary Δp is shifted by ΔP, Q is shifted from the predetermined Q by ΔQ. The rate of change of Q with respect to Δp is smaller in this example than in the comparative example. Therefore, ΔQ corresponding to the same ΔP is smaller in this example than in the comparative example (ΔQ ₂ <ΔQ ₁ ). That is, even if the same load acts on the control valve 8, the change in the flow rate is smaller in the present embodiment than in the comparative example. For this reason, the deviation of the control flow rate can be reduced.

In order to prevent the control valve 8 from being locked due to contamination, it is conceivable to increase the clearance area between the control valve 8 and the valve housing hole 227 around the control valve 8. However, increasing the clearance area of the clearance portion increases the amount of leakage around the control valve 8 (via the clearance portion). Thereby, the efficiency of a pump will fall. On the other hand, in this embodiment, it is possible to generate a large differential pressure Δp with a relatively small flow rate Q while suppressing energy loss in the throttle portion. Therefore, the diameter of the control valve 8 can be reduced without greatly reducing the force F1-F2 acting on the control valve 8. By reducing the diameter of the control valve 8, the clearance area of the clearance portion can be reduced. Thereby, since the leakage amount around the control valve 8 is reduced, it is possible to suppress a reduction in pump efficiency.

The narrow angle θ sandwiched between the inner walls of the inner diameter gradually increasing portion 52 is the spread angle of the outlet in the venturi portion 50 as the throttle portion. By setting θ to 60 degrees or less, a sufficient pressure loss suppressing effect can be obtained. FIG. 9 shows the relationship between θ and the pressure loss ratio. The pressure loss ratio is a ratio when the pressure loss in the comparative example is 1. When θ is 60 degrees or less, the pressure loss ratio is less than 1. That is, the pressure loss is smaller than that of the comparative example. In this embodiment, the venturi portion 50 (inner diameter gradually increasing portion 52) is formed so that θ is 60 degrees or less. Therefore, pressure loss is suppressed as compared with the comparative example. For this reason, the efficiency fall of a pump can be suppressed more reliably. For example, by setting θ to about 15 degrees, an excessive increase in the longitudinal length (axial dimension) of the venturi 50 can be suppressed while obtaining a sufficient pressure loss suppressing effect.

In the venturi forming block accommodation hole 228, the space on the x-axis negative direction side of 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 receiving hole 228 is larger than the inner diameter of the second hole 222. That is, the space on the upstream side of the venturi portion 50 in the discharge passage 5 is a large-diameter portion 53 having an inner diameter larger than that on the downstream side (second hole 222). The pressure in the large-diameter portion 53 is introduced into the high-pressure chamber 86 of the control valve 8 as the pressure (high pressure) upstream of the venturi portion 50. Therefore, FIG. 6 can be redrawn as shown in FIG. In FIG. 10, the flow velocity in the large-diameter portion 53 is u ₁ *, and the pressure is p ₁ *. Other reference numerals are the same as those in FIG. If the inner diameter (cross-sectional area) of the large-diameter portion 53 is larger than the inner diameter (cross-sectional area) of the discharge passage 5 upstream of the large-diameter portion 53, u ₁ * will be smaller than u ₁ (≈u ₃ ). Along with this, p ₁ * rises above p ₁ (≈p ₃ ). Others are the same as FIG. Therefore, if the differential pressure generated by the venturi portion 50 (small diameter portion 51) is Δp *, Δp * (= p ₁ * −p ₂ )> Δp (= p ₁ −p ₂ ), and the large diameter portion 53 is provided. The differential pressure becomes larger than that in the case where there is not (FIG. 6). As a result, the force difference F1-F2 acting on the control valve 8 is increased, so that the above-described operational effect can be obtained more effectively.

The inner diameter at the other end in the axial direction of the inner diameter gradually increasing portion 52 that opens to the end surface on the other axial side of the venturi forming block 21 is slightly smaller than the inner diameter of the second hole 222. Therefore, FIG. 6 can be redrawn as shown in FIG. The inner diameter gradually increasing portion 52 has an upstream tapered portion formed with a constant θ at 60 degrees or less (specifically, approximately 15 degrees), and the discharge passage 5 downstream from the venturi section 50 at 60 degrees or more. And a step portion on the downstream side continuous with a large θ. Hereinafter, the tapered portion on the upstream side is referred to as a front portion 520, and the step portion on the downstream side is referred to as a rear portion 521. The inner diameter gradually increasing portion 52 has a front portion 520 and a rear portion 521. In this embodiment, θ of the rear portion 521 is approximately 180 degrees. That is, the rear portion 521 extends so as to be substantially orthogonal to the inner wall of the discharge passage 5 on the downstream side of the venturi portion 50. It is assumed that the inner diameter gradually increasing portion 52 is formed until θ is equal to or smaller than the inner diameter of the discharge passage 5 on the downstream side of the venturi portion 50 while being constant at 60 degrees or less. The longitudinal length of 52 is L0. The length of the front portion 520 in the longitudinal direction is L.

Fig. 12 shows the relationship between the ratio L / L0 of L to L0 and the pressure loss ratio. The pressure loss ratio is a ratio when the pressure loss when L / L0 is 0, in other words, the pressure loss in the comparative example is 1. When L / L0 is greater than 0 and less than or equal to 0.65, the pressure loss ratio decreases as L / L0 increases. In the range where L / L0 is larger than 0.65, even if L / L0 increases, the pressure loss ratio does not decrease any more. Therefore, pressure loss can be suppressed as compared with the comparative example if a certain region (the front portion 520) in which θ is 60 degrees or less is secured. However, even if the length L of the front portion 520 is longer than 65% of L0, no further pressure loss suppression effect can be obtained. Therefore, it is preferable to form the front portion 520 to a position where L is 65% or less of L0, so that L / L0 is greater than 0 and 0.65 or less. In this case, a rear portion 521 having θ larger than 60 degrees is provided on the downstream side of the front portion 520. As described above, the rear portion 521 does not maintain θ of 60 degrees or less, so that the venturi 50 is connected to the downstream discharge passage 5 with a relatively short length (less than L0) (based on the inner diameter of the venturi 50). You can return to Thereby, the longitudinal direction length of the venturi part 50 can be suppressed. If the θ of the rear portion 521 is close to approximately 180 degrees as shown in FIG. 11, the above-described length suppressing effect can be improved. In a range where L / L0 is greater than 0 and less than or equal to 0.65, the amount of decrease (decrease rate) in the pressure loss ratio relative to the increase in L / L0 increases as L / L0 approaches 0. If L / L0 is in the range of 0.4 or more, a sufficiently small pressure loss ratio (sufficiently close to the pressure loss ratio when L / L0 is 0.65) can be obtained. Therefore, it is preferable to form the front portion 520 so that L / L0 is 0.4 or more, in other words, to a position where L is 40% or more of L0. In this case, the length suppression effect can be improved by bringing L close to 40% of L0 while obtaining a sufficient pressure loss suppression effect.

The venturi 50 is longer than the orifice (large dimension in the axial direction). For this reason, processing is relatively difficult. In contrast, in the present embodiment, the venturi portion 50 is formed in the venturi forming block 21. This venturi forming block 21 is joined to the pump housing body 20. As a result, the venturi 50 is realized in the pump housing body 20. Thus, by forming the venturi section 50 in the venturi forming block 21 which is a separate member from the pump housing body 20, the workability of the venturi section 50 can be improved. Note that what is formed in the venturi forming block 21 may be at least the small diameter portion 51 and the inner diameter gradually increasing portion 52 constituting the venturi portion 50. In other words, the throttle part and the inner diameter gradually decreasing part 210 having the same diameter as the small diameter part 51 and having a predetermined length may be provided on the pump housing body 20 side, or may be provided on the venturi forming block 21 side. Good. The venturi forming block 21 is formed of a 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 formed more easily than when the inner diameter gradually increasing portion 52 is formed by machining.

Also, the venturi section 50 requires a longer dimension (space in the longitudinal direction) than the orifice. On the other hand, in the present embodiment, the venturi portion 50 is arranged such that the longitudinal direction (x-axis direction) of the venturi portion 50 and the direction of the rotation axis (axis O) of the drive shaft 40 (z-axis direction) are substantially orthogonal. Is placed. Therefore, an increase in the size of the pump device in the direction of the rotation axis of the drive shaft 40 (axial direction) can be suppressed. On the other hand, the pump housing 2 originally has dimensions for accommodating the control valve 8. On the other hand, in this embodiment, the venturi portion 50 is arranged so that the longitudinal direction of the venturi portion 50 and the longitudinal direction of the control valve 8 are substantially parallel. In this way, by arranging the venturi portion 50 so as to utilize the originally existing space extending in the longitudinal direction of the control valve 8, an increase in the outer shape of the pump device (in the radial direction of the control valve 8) is suppressed. be able to.

Also, the venturi section 50 is arranged so that the discharge passage 5 upstream from the venturi section 50 faces the high pressure chamber 86 of the control valve 8. Therefore, it is possible to shorten the high-pressure passage 6 (first hole 221) that communicates the upstream side of the venturi section 50 with the high-pressure chamber 86. Specifically, the venturi forming block accommodation hole 228 and the valve accommodation hole 227 both extend in the x-axis direction and are arranged substantially parallel to each other. The first hole 221 linearly extends in the y-axis direction, and is connected to the x-axis negative direction side of the venturi forming block accommodating hole 228 in the x axis negative direction and the high pressure chamber 86 in the valve accommodating hole 227, The upstream side of the venturi section 50 and the high pressure chamber 86 are connected with the shortest distance. The venturi portion 50 may be arranged so 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, it is possible to shorten the intermediate pressure passage 7 (fourth hole 224) that communicates the second communication groove 215 and the intermediate pressure chamber 88.

The communication hole 213 of the venturi forming block 21 opens on the inner peripheral surface of the venturi section 50 on the radially inner side. The communication hole 213 is provided in the venturi section 50 and functions as an opening for introducing the pressure in the venturi section 50 into the control valve 8 (intermediate pressure chamber 88). Here, since the discharge passage 5 on the upstream side of the venturi section 50 has a bend or the like, the flow velocity distribution in the direction around the axis along the longitudinal direction (hereinafter referred to as the circumferential direction) in the passage 5 is obtained. Bias may occur. In this case, the pressure distribution in the circumferential direction in the venturi 50 is also biased. This bias changes depending on the flow rate and temperature conditions. On the other hand, in this embodiment, a plurality (four) of the openings of the communication hole 213 are provided in the circumferential direction of the venturi portion 50. As described above, by extracting the pressure from a plurality of locations in the circumferential direction in the venturi section 50, the pressure in the venturi section 50 is stably introduced into the intermediate pressure chamber 88 in spite of the uneven pressure distribution. be able to. That is, the pressure (working fluid) taken out from the openings of the plurality of communication holes 213 is collected in one intermediate pressure passage 7 (fourth hole 224) via the first and

second communication grooves

214 and 215, and thereafter The medium pressure chamber 88 is introduced. At this time, the pressure distribution bias is canceled out, and the average pressure in the circumferential direction in the venturi 50 is introduced into the intermediate pressure chamber 88. Therefore, variation in pressure taken out from the venturi 50 is reduced. Therefore, the operation of the control valve 8 is stabilized, and the deviation of the control flow rate is reduced. The number of communication holes 213 may be two or more and is arbitrary. In the present embodiment, since the openings of the communication holes 213 are arranged at substantially equal intervals in the circumferential direction, variations in pressure taken out from the venturi 50 can be more stably reduced.

The communication hole 213 is provided at a position overlapping the small diameter part 51 in the axial direction (longitudinal direction) of the venturi part 50. That is, the opening of the communication hole 213 is provided in the small diameter portion 51. Therefore, the pressure is extracted from the smallest diameter portion of the venturi portion 50, that is, the portion where the pressure is lowest, and is introduced into the intermediate pressure chamber 88. Thereby, the differential pressure generated in the venturi portion 50 can be utilized most efficiently.

[Example 2]
The pump device 1 of the second embodiment is different from the first embodiment in the configuration of the venturi forming block 21. Only the configuration different from the first embodiment will be described below. The components common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted. FIG. 13 shows a cross section of the venturi forming block 21 taken along a plane passing through the axis of the venturi section 50. The venturi forming block 21 is not provided with the inner diameter gradually decreasing portion 210 as in the first embodiment. The small diameter portion 51 opens on the end surface on the one axial side of the venturi forming block 21 (the outer surface of the venturi forming block 21). The communication hole 213 is provided at a position overlapping with one axial side of the inner diameter gradually increasing portion 52 (the small diameter portion 51 side). The radially inner end of the communication hole 213 opens on one axial side of the inner diameter gradually increasing portion 52 (the small diameter portion 51 side). The communication hole 213 constitutes a part of the intermediate pressure passage 7. The communication hole 213 introduces the pressure on the one side in the axial direction of the inner diameter gradually increasing portion 52 (the small diameter portion 51 side) out of the pressure in the venturi portion 50 into the intermediate pressure chamber 88 of the control valve 8.

Next, the operation will be described. As in the present embodiment, the pressure in the venturi portion 50 introduced into the intermediate pressure chamber 88 is not limited to the pressure in the small diameter portion 51 but may be the pressure in the gradually increasing inner diameter portion 52. The pressure on one side in the axial direction of the gradually increasing inner diameter portion 52 (the smaller diameter portion 51 side) is introduced into the intermediate pressure chamber 88. Therefore, a lower pressure can be used among the pressures in the inner diameter gradually increasing portion 52. For this reason, a sufficiently large differential pressure can be applied to the control valve 8.

If the small-diameter portion 51 does not open to the outer surface of the venturi forming block 21 and is provided inside the venturi forming block 21, when molding the venturi portion 50, molds are formed from both axial sides of the venturi forming block 21. It is necessary to insert. When machining the venturi section 50, it is necessary to machine the venturi forming block 21 from both axial sides. On the other hand, in the present embodiment, the small diameter portion 51 opens on the outer surface of the venturi forming block 21. Therefore, when molding the venturi portion 50, it is sufficient to insert the die only from the opening side of the inner diameter gradually increasing portion 52 in the axial direction of the venturi forming block 21. When machining the venturi 50, it is sufficient to machine only from the opening side of the inner diameter gradually increasing portion 52 in the axial direction of the venturi forming block 21. Therefore, the manufacturability of the venturi portion 50 (the venturi forming block 21) is improved.

[Example 3]
In the pump device 1 according to the third embodiment, the pump housing body 20 is formed of a metal material as in the first embodiment. On the other hand, unlike the first embodiment, the venturi forming block 21 is also formed of a metal material. Specifically, the venturi forming block 21 is formed of a sintered material. When the metal powder is compacted in the compacting process, the venturi 50 is formed by a mold. By sintering this molded body, the venturi forming block 21 is formed.

When the venturi forming block 21 is joined to the pump housing body 20 (the venturi forming block receiving hole 228 of the rear body 22), distortion occurs between the venturi forming block 21 and the pump housing body 20 after joining, etc. Problems can arise. On the other hand, in the present embodiment, the venturi forming block 21 is made of a metal material. For this reason, the linear expansion coefficient is close to that of the pump housing body 20. Therefore, the occurrence of the above problems can be suppressed. Further, the venturi part 50 (inner diameter gradually increasing part 52, etc.) is formed by a mold. Therefore, compared to the case where the venturi portion 50 (inner diameter gradually increasing portion 52 or the like) is formed by machining, the formation becomes easier.

[Example 4]
The pump device 1 of the fourth embodiment is different from the first embodiment in the arrangement of the venturi portion 50 and the like. Only the configuration different from the first embodiment will be described below. The components common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted. FIG. 14 is a view of the pump housing 2 as viewed from the direction in which the drive shaft 40 (axial center O) extends (z-axis negative direction), and the internal structure and part of the housing components are indicated by broken lines. FIG. 15 shows a cross section taken along the line BB of FIG. The setting of the orthogonal coordinate system is the same as in the first embodiment (FIG. 3 and the like). The pump housing 2 does not have the venturi forming block 21 as in the first embodiment. The pump housing body 20 (rear body 22) does not have the venturi forming block accommodation hole 228 as in the first embodiment. The inner diameter gradually decreasing portion 210 and the venturi portion 50 are formed directly inside the rear body 22.

The inner diameter gradually decreasing portion 210 and the venturi portion 50 extend in the z-axis direction on the x-axis positive direction side and the y-axis negative direction side of the rear body 22. That is, the longitudinal direction of the venturi 50 is substantially parallel to the direction of the axis O (z-axis direction) and is orthogonal to the longitudinal direction (x-axis direction) of the valve housing hole 227. The venturi 50 does not overlap with the housing recess 220 in the direction orthogonal to the z-axis (the radial direction with respect to the rotation axis of the drive shaft 40) (outside in the radial direction from the housing recess 220). It overlaps with the housing recess 220. The inner diameter gradually decreasing portion 210 has a first inner diameter gradually decreasing portion 210a sandwiched between the inner walls and having a relatively small narrow angle, and a second inner diameter gradually decreasing portion 210b having a relatively small narrow angle. The z axis positive direction end of the first inner diameter gradually decreasing portion 210a opens on the surface of the rear body 22 on the z axis positive direction side. The inner diameter of the first inner diameter gradually decreasing portion 210a gradually decreases from the z-axis positive direction side toward the z-axis negative direction side. The z axis positive direction end of the second inner diameter gradually decreasing portion 210b is connected to the z axis negative direction end of the first inner diameter gradually decreasing portion 210a. The inner diameter of the second inner diameter gradually decreasing portion 210b gradually decreases from the z-axis positive direction side toward the z-axis negative direction side. The z axis positive direction end of the small diameter portion 51 is connected to the z axis negative direction end of the second inner diameter gradually decreasing portion 210b. The z axis negative direction end of the small diameter portion 51 is connected to the z axis positive direction end of the inner diameter gradually increasing portion 52. The inner diameter of the inner diameter gradually increasing portion 52 gradually increases from the z-axis positive direction side toward the z-axis negative direction side. The z axis negative direction end of the inner diameter gradually increasing portion 52 opens on the surface of the rear body 22 on the z axis negative direction side.

The second hole 222 extends in the z-axis direction on the x-axis negative direction side and the y-axis negative direction side of the rear body 22. The z-axis negative direction end of the second hole 222 is connected to the y-axis negative direction end of the first hole 221. The z-axis positive direction end of the second hole 222 opens on the surface of the rear body 22 on the z-axis positive direction side. The third hole 223 is formed inside the front body 24 and is disposed so as to extend in the x-axis direction. The end of the third hole 223 on the x-axis negative direction side bends to the z-axis negative direction side, opens on the surface of the front body 24 on the z-axis negative direction side, and extends to the z-axis positive direction end of the second hole 222. Connecting. The end of the third hole 223 on the x-axis positive direction side bends in the z-axis negative direction side, opens on the surface of the front body 24 on the z-axis negative direction side, and the z-axis positive direction of the first inner diameter gradually decreasing portion 210a. Connect to the end. The inner diameter of the end portion on the positive z-axis direction side of the first inner diameter gradually decreasing portion 210a is substantially equal to the inner diameter of the third hole 223. The fourth hole 224 connects the positive end of the valve housing hole 227 in the x-axis direction and the small diameter part 51 of the venturi part 50.

Next, the function and effect will be described. The pump housing 2 does not have the venturi forming block 21, and the inner diameter gradually decreasing portion 210 and the venturi portion 50 are formed directly inside the pump housing 2 (rear body 22). Therefore, the number of parts can be reduced.

The venturi unit 50 requires a longer dimension (longitudinal space) than the orifice. On the other hand, the pump housing 2 originally has dimensions in the direction of the rotation axis of the drive shaft 40 for housing the pump element 4. In the present embodiment, the pump element accommodating portion (accommodating recess 220) overlaps with the pump element accommodating portion (accommodating recess 220) in the radial direction outside the pump element accommodating portion (accommodating recess 220) in the direction of the rotation axis (axial center O) of the drive shaft 40. Thus, the venturi part 50 is arranged. Thus, by arranging the venturi unit 50 so as to utilize the space that originally exists in the direction of the rotation axis of the drive shaft 40, the outer shape of the pump device 1 (in the direction of the rotation axis of the drive shaft 40) is large. Can be suppressed. Further, the venturi section 50 is arranged so that the longitudinal direction of the venturi section 50 and the direction of the rotation axis (axis O) of the drive shaft 40 are substantially parallel. Therefore, an increase in the size of the pump device 1 in the radial direction with respect to the rotation shaft of the drive shaft 40 can be suppressed. Note that the effect of the above arrangement can also be obtained when the venturi portion 50 is formed in the venturi forming block 21.

[Example 5]
The pump device 1 of the fifth embodiment is different from the first embodiment in the housing in which the venturi unit 50 and the control valve 8 are installed. Only differences from the first embodiment will be described below. The transmission housing 10 a is a CVT unit housing and is a separate member from the pump housing 2. The pump housing 2 may be disposed integrally with the transmission housing 10a or may be disposed apart from the transmission housing 10a. The pump element 4 is provided in the pump housing 2, while the venturi 50 and the control valve 8 are provided in a transmission housing (for example, a control valve housing) 10a, as indicated by the broken line in FIG.

Thus, by providing the venturi unit 50 or the control valve 8 not on the pump housing 2 side but on the transmission housing 10a side, the unit including the pump element 4 can be downsized and its layout can be improved. When the control valve 8 is provided on the transmission housing 10a side, the hydraulic fluid supplied from the pump element 4 (pump housing 2) to the transmission housing 10a is a flow rate before being controlled by the control valve 8. The control valve 8 controls the flow rate of the hydraulic fluid supplied from the pump element 4 to the CVT 10. The “flow rate of hydraulic fluid supplied from the pump element 4 to the CVT 10” means a flow rate actually supplied to the CVT 10 existing inside the transmission housing 10a. 1, the venturi 50 may be provided in the transmission housing 10a, and the pump element 4 and the control valve 8 may be provided in the pump housing 2. Further, the venturi unit 50 and the control valve 8 may be provided in a housing other than the transmission housing 10a.

[Example 6]
The pump element 4 of Example 6 is a variable displacement type in which the pump displacement is variably controlled. Only the configuration different from the first embodiment will be described below. The components common to the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted. FIG. 16 is a diagram similar to FIG. 2, showing the schematic configuration of the pump device 1. FIG. 17 shows a partial cross section of the pump housing 2 taken along a plane including the axis O. The z axis is provided in the left-right direction in FIG. 17, and the right side is positive. The rear body 22 includes a housing recess 220, a suction pressure chamber 220a, a discharge pressure chamber 226, a valve housing hole 227, a venturi forming block housing hole (not shown), a bearing holding hole 229, a plurality of passages 3, and the like. The plurality of passages 3 and the like have a suction passage 3, a discharge passage 5, a high pressure passage 6, an intermediate pressure passage 7, a first control passage 60, a second control passage 70, and a return passage 9. A suction pressure chamber 220a and a discharge pressure chamber 226 are opened at the bottom of the housing recess 220. A bush 401 as a bearing is installed on the inner periphery of the bearing holding hole 229. The end of the valve housing hole 227 in the negative x-axis direction opens on the outer surface of the rear body 22. A solenoid 80 is fitted into the opening via a seal member 253. A rod 800 protrudes from the solenoid 80 in the positive x-axis direction.

The side plate 23 is provided with a shaft receiving hole 234. A suction port 230, a discharge port 231, a suction side back pressure port 232, and a discharge side back pressure port 233 are provided on the surface on one side in the axial direction of the side plate 23. The suction port 230 and the discharge port 231 are grooves extending in a substantially arc shape in the circumferential direction, and are provided at positions facing each other across the shaft housing hole 234. The suction-side back pressure port 232 is a groove that extends in a substantially arc shape in the circumferential direction on the side of the shaft accommodation hole 234 from the suction port 230 (inside in the radial direction), and is provided in a range that overlaps the suction port 230 in the circumferential direction. The discharge-side back pressure port 233 is a groove extending in a substantially arc shape in the circumferential direction on the radially inner side of the discharge port 231 and is provided in a range overlapping the discharge port 231 in the circumferential direction. The suction port 230 and the suction side back pressure port 232 are connected to the suction pressure chamber 220a of the rear body 22 via the communication path in the side plate 23. The discharge port 231 and the discharge side back pressure port 233 are connected to the discharge pressure chamber 226 via a communication path in the side plate 23. An annular seal groove is formed on the surface of the side plate 23 in the negative z-axis direction so as to surround the outer edge of the side plate 23. An annular seal member 250 is installed in the seal groove. An annular seal groove is formed on the bottom surface of the housing recess 220 on the z-axis positive direction side so as to surround the opening of the bearing holding hole 229. An annular seal member 251 is installed in the seal groove. An annular seal groove is formed on the surface of the bottom portion of the housing recess 220 on the z-axis positive direction side so as to surround the outer periphery of the opening of the discharge pressure chamber 226. An annular seal member 252 is installed in the seal groove. The seal member 252 defines a high pressure region on the inner peripheral side of the seal member 252 and a low pressure region on the outer peripheral side.

A bush 402 serving as a bearing is installed on the inner periphery of the bearing holding hole 244 of the front body 24. A suction port 240 and a discharge port 241, a suction-side back pressure port 242 and a discharge-side back pressure port 243 are formed on the end surface in the negative z-axis direction of the front body 24. 232 and 233 are formed at positions substantially corresponding to the z-axis direction and in the same shape. The front body 24 is fastened and fixed to the rear body 22 by bolts 26.

In the housing recess 220 of the rear body 22, an adapter ring 44 is installed on the side plate 23 in the positive z-axis direction. The adapter ring 44 has an annular shape, and the outer periphery of the adapter ring 44 is fitted to the inner periphery of the housing recess 220. The inner peripheral surface of the adapter ring 44 has a substantially cylindrical shape extending in the z-axis direction, and is substantially elliptical when viewed from the z-axis direction. A first groove portion 441, a second groove portion 442, a first plane portion 443, a second plane portion 444, and a recess 445 are provided on the inner peripheral surface. The first groove portion 441 has a semicylindrical shape extending in the z-axis direction, and is provided in the first plane portion 443. On both sides of the first groove 441, there are provided first and

second control passages

60, 70 penetrating the adapter ring 44 in the radial direction. The second groove portion 442 is provided on the opposite side of the first groove portion 441 across the center (axial center) of the adapter ring 44 and extends in the z-axis direction. The second plane portion 444 is provided between the first and second groove portions 441 and 442 (substantially intermediate position) in the circumferential direction of the adapter ring 44. The concave portion 445 is provided on the opposite side of the second flat portion 444 across the center of the adapter ring 44.

The pump element 4 is accommodated in a space surrounded by the inner peripheral surface of the adapter ring 44, the surface of the side plate 23 on the z-axis positive direction side, and the surface of the front body 24 on the z-axis negative direction side. That is, the space functions as a pump element housing portion. The rotor 41 is provided with eleven slits 410. The cam ring 43 is formed in an annular shape, and its inner peripheral surface is substantially cylindrical. A semi-cylindrical groove 433 extending in the z-axis direction is provided on the outer peripheral surface of the cam ring 43. The cam ring 43 is disposed so as to surround the rotor 41 in the pump element housing portion. The cam ring 43 forms a plurality of pump chambers 400 together with the rotor 41 and the vanes 42. That is, the side plate 23 and the front body 24 are disposed on the axial side surfaces of the cam ring 43 and the rotor 41. The space between the inner peripheral surface of the cam ring 43 and the outer peripheral surface of the rotor 41 is sealed on both sides in the axial direction by the side plate 23 and the front body 24, while the plurality of vanes 42 provide eleven pump chambers 400. It is divided into.

The cam ring 43 is movably provided in the pump element housing. A pin 453 is fitted and installed 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 suppresses rotation of the adapter ring 44 with respect to the pump housing 2 and suppresses rotation of the cam ring 43 with respect to the adapter ring 44. The cam ring 43 is accommodated on the inner peripheral side of the adapter ring 44 so as to be swingable with respect to the pump housing 2. The cam ring 43 is supported by the first flat portion 443 with respect to the adapter ring 44. The cam ring 43 rolls on the first flat surface portion 443 and swings about the first flat surface portion 443 as a fulcrum. The amount of deviation of the center (axial center) of the inner peripheral surface of the cam ring 43 with respect to the center (axial center O) of the rotor 41 (drive shaft 40) is hereinafter referred to as an eccentricity δ.

The seal member 46 is installed in the second groove portion 442 of the adapter ring 44. When the cam ring 43 swings, the first flat portion 443 of the adapter ring 44 contacts the outer peripheral surface of the cam ring 43 and the seal member 46 contacts the outer peripheral surface of the cam ring 43. The space between the inner peripheral surface of the adapter ring 44 and the outer peripheral surface of the cam ring 43 is liquid-tight by a first flat portion 443 (a contact portion with the outer peripheral surface of the cam ring 43) and the seal member 46. Separated into pairs of spaces. That is, two

fluid pressure chambers

61 and 71 are formed as a pair of spaces between the cam ring 43 and the pump element accommodating portion. For convenience of explanation, as shown in FIG. 16, the X axis is taken in the major axis direction and the Y axis is taken in the minor axis direction of the inner peripheral surface of the adapter ring 44 which is substantially elliptical. On the outer peripheral side of the cam ring 43, the first fluid pressure chamber 61 is formed on the X axis negative direction side where the eccentric amount δ increases, and the second axis is formed on the X axis positive direction side where δ decreases. A fluid pressure chamber 71 is formed. When δ increases, the volume of the first fluid pressure chamber 61 decreases and the volume of the second fluid pressure chamber 71 increases. Inside the second fluid pressure chamber 71, one end of the spring 47 is installed in the recess 445 of the adapter ring 44. The other end of the spring 47 is installed on the outer peripheral side of the cam ring 43. The spring 47 is installed in a compressed state, and always biases the cam ring 43 toward the X axis negative direction side (the first fluid pressure chamber 61 side) with respect to the adapter ring 44. The movement of the cam ring 43 in the negative X-axis direction is restricted by the outer peripheral surface of the cam ring 43 abutting against the second flat surface portion 444 of the adapter ring 44 inside the first fluid pressure chamber 61.

Rotator 41 rotates in the clockwise direction in FIG. In a state where the center of the cam ring 43 is decentered with respect to the axis O (to the X axis negative direction side), the outer peripheral surface of the rotor 41 and the inner periphery of the cam ring 43 move from the X axis positive direction side to the X axis negative direction side. The radial distance between the surfaces (the radial dimension of the pump chamber 400) increases. As the distance changes, the vanes 42 appear and disappear from the slits 410 to separate the pump chambers 400. The pump chamber 400 on the X axis negative direction side has a larger volume than the pump chamber 400 on the X axis positive direction side. Due to the difference in the volume of the pump chamber 400, the volume of the pump chamber 400 is reduced as the rotor 41 rotates (the pump chamber 400 moves toward the X axis positive direction) on the Y axis positive direction side of the axis O. On the Y axis negative direction side of the axis O, the volume of the pump chamber 400 increases as the rotor 41 rotates (the pump chamber 400 moves toward the X axis negative direction side). The pump chamber 400 periodically expands and contracts while rotating around the axis O in the clockwise direction. The suction port 230 opens to a suction region where the volume of the pump chamber 400 increases as the drive shaft 40 rotates. The discharge port 231 opens to a discharge region where the volume of the pump chamber 400 decreases as the drive shaft 40 rotates.

The suction passage 3 connects the oil pan 100 and the suction pressure chamber 220a. The discharge passage 5 connects the discharge pressure chamber 226 and the CVT 10. The high-pressure passage 6 branches from the discharge passage 5 on the upstream side of the venturi portion 50 in the discharge passage 5 and is connected to the x-axis positive direction side of the valve housing hole 227. The intermediate pressure passage 7 branches off from the venturi portion 50 (small diameter portion 51) in the discharge passage 5 and is connected to the x-axis negative direction side of the valve housing hole 227. The first control passage 60 and the second control passage 70 connect the control valve 8 and the pump element 4. The first control passage 60 is connected to the positive side of the x-axis with respect to the high-pressure passage 6 in the valve housing hole 227 and is connected to the first fluid pressure chamber 61 through the adapter ring 44. The second control passage 70 is connected to the x-axis negative direction side with respect to the intermediate pressure passage 7 in the valve housing hole 227 and is connected to the second fluid pressure chamber 71 through the adapter ring 44. The return passage 9 is connected between the first control passage 60 and the second control passage 70 in the valve housing hole 227. Regardless of the movement of the control valve 8 inside the valve housing hole 227, the high pressure passage 6 opens in the high pressure chamber 86, the intermediate pressure passage 7 opens in the intermediate pressure chamber 88, and the return passage 9 passes through the drain chamber 89. Opens.

The control valve 8 switches the flow path of the hydraulic fluid between the first control passage 60 and the second control passage 70. In the initial state where the control valve 8 is displaced to the maximum in the negative direction of the x-axis, the opening of the first control passage 60 in the valve housing hole 227 is disconnected from the high pressure chamber 86 by the first land portion 81, Communicates with drain chamber 89. In the same initial state, the opening of the second control passage 70 is communicated with the intermediate pressure chamber 88 while the communication with the drain chamber 89 is blocked by the second land portion 82. As a result, the hydraulic fluid in the intermediate pressure chamber 88 flows into the second fluid pressure chamber 71. Since the high pressure is not supplied to the first fluid pressure chamber 61 and the intermediate pressure is supplied to the second fluid pressure chamber 71, the cam ring 43 is in an eccentric state. Therefore, the pump discharge flow rate increases according to the rotation speed. In a state where the control valve 8 has moved to the x-axis positive direction side by a predetermined amount or more, the opening of the first control passage 60 is disconnected from the drain chamber 89 by the first land portion 81, while the high-pressure chamber 86 Communicate. In the same state, the opening of the second control passage 70 is communicated with the drain chamber 89 while the communication with the intermediate pressure chamber 88 is blocked by the second land portion 82. As a result, the flow path is switched, and the hydraulic fluid in the high pressure chamber 86 flows into the first fluid pressure chamber 61 via the first control passage 60. High pressure is supplied to the first fluid pressure chamber 61, and medium pressure is not supplied to the second fluid pressure chamber 71. Therefore, the amount of eccentricity δ of the cam ring 43 is reduced and the pump capacity is reduced, so that the pump discharge flow rate does not increase even if the pump rotational speed is increased. That is, the control valve 8 is configured so that the hydraulic fluid introduced through the high pressure passage 6 is introduced into the first fluid pressure chamber 61 based on the differential pressure Δp between the upstream side of the venturi portion 50 and the small diameter portion 51. Switch the flow path. When the hydraulic fluid is introduced into the first fluid pressure chamber 61, the flow rate supplied to the CVT 10 via the discharge passage 5 is limited to a necessary amount. Thus, the venturi section 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 are pumps. It functions as a control unit that controls the discharge flow rate of the element 4.

The operation of the control valve 8 is controlled by a differential pressure Δp acting on both sides in the axial direction of the control valve 8 according to the discharge flow rate of the pump element 4, and is also controlled by a thrust acting on the control valve 8 from the solenoid 80. . That is, the tip of the rod 800 of the solenoid 80 abuts on the end surface of the control valve 8 in the negative x-axis direction. The rod 800 can be moved in the x-axis direction by the electromagnetic force generated by the solenoid 80. A force F4 from the solenoid 80 to the x-axis positive direction side acts on the control valve 8 via the rod 800. The thrust F4 of the solenoid 80 is controlled based on a command from the CVT control unit. When the sum (F1−F2 + F4) of the difference F1-F2 between F1 and F2 (the force corresponding to the differential pressure Δp) and F4 exceeds F3, the control valve 8 moves to the x-axis positive direction side. When the solenoid 80 is inactive, the force facing the initial set load F3 of the spring 88 is only the force F1-F2 due to the differential pressure Δp. On the other hand, if the discharge flow rate does not increase to some extent, a sufficient differential pressure Δp (that is, F1-F2) cannot be ensured. Therefore, after achieving a relatively high discharge flow rate, a constant flow rate is maintained. When the solenoid 80 is energized to generate F4, the same effect as that obtained by changing the initial set load F3 of the spring 88 small can be obtained. That is, the control valve 8 moves with a relatively small differential pressure Δp (that is, F1-F2), and the flow path is switched. Therefore, a constant flow rate is maintained after a relatively low discharge flow rate is achieved. Thus, the discharge flow rate can be controlled by the magnetic attractive force (thrust F4) generated by the solenoid 80. The CVT control unit appropriately controls the line pressure of the CVT 10 according to the driving situation such as the engine speed, the accelerator opening (throttle valve opening), and the vehicle speed. In response to this, the CVT control unit supplies current to the solenoid 80 based on the engine speed, the accelerator opening, etc., and controls the magnetic attractive force (thrust force F4), so that the discharge flow rate (pump of the pump element 4) Change the capacity. The solenoid 80 may be omitted.

In the present embodiment, the same effects as those of the venturi unit 50 can be obtained in the variable displacement pump as in the first embodiment.

[Other embodiments]
As mentioned above, although the pump apparatus of this invention was demonstrated based on the Example, the concrete structure of this invention is not limited to an Example, Even if there is a design change etc. of the range which does not deviate from the summary of invention. It is included in the present invention. For example, the continuously variable transmission to which the pump device supplies the hydraulic fluid is not limited to the CVT, and may be a toroidal type, for example. The automatic transmission to which the pump device supplies hydraulic fluid is not limited to a continuously variable transmission, but may be a stepped transmission. The on-vehicle equipment to which the pump device supplies the hydraulic fluid is not limited to the automatic transmission, but may be a power steering device or the like. Moreover, it is possible to combine the structure of each Example suitably.

This application claims priority based on Japanese Patent Application No. 2015-004311 filed on January 13, 2015. The entire disclosure including the specification, claims, drawings, and abstract of Japanese Patent Application No. 2015-004311 filed on January 13, 2015 is incorporated herein by reference in its entirety.

1 pump device, 10 CVT (automatic transmission), 2 pump housing, 20 pump housing body, 21 venturi forming block, 213 communication hole (opening), 230 intake port, 231 discharge port, 4 pump element, 40 drive shaft, 400 Pump chamber, 41 rotor, 410 slit, 42 vane, 43 cam ring, 5 discharge passage, 50 venturi section, 51 small diameter section, 52 inner diameter gradually increasing section, 520 front section, 521 rear section, 53 large diameter section, 61 first fluid pressure Chamber, 71 second fluid pressure chamber, 8 control valve, 86 high pressure chamber, 87 medium pressure chamber

Claims

A pump device for an automatic transmission for supplying hydraulic fluid to an automatic transmission of a vehicle,
A pump housing having a pump element housing;
A drive shaft pivotally supported by the pump housing;
A pump element that is provided in the pump element housing and is rotationally driven by the drive shaft and forms a plurality of pump chambers around the drive shaft;
A suction port formed in the pump housing and opening to a suction region in which the volume of the plurality of pump chambers increases with rotation of the drive shaft;
A discharge port that is formed in the pump housing and opens to a discharge region in which the volume of the plurality of pump chambers decreases as the drive shaft rotates;
A discharge passage connected to the discharge port;
A venturi portion provided in the middle of the discharge passage, a small diameter portion having an inner diameter smaller than the inner diameter of the discharge passage from the discharge port to the venturi portion, and from the small diameter portion to the downstream side of the discharge passage A venturi section having an inner diameter gradually increasing portion formed so that the inner diameter gradually increases toward the inner surface,
A hydraulic valve in the upstream of the venturi and in the venturi is introduced, and includes a spool valve body that is controlled based on a differential pressure between the hydraulic fluid in the upstream of the venturi and the hydraulic fluid in the venturi, and at least A control valve for controlling the flow rate of the hydraulic fluid supplied to the automatic transmission by switching the flow path of the hydraulic fluid introduced from the upstream side of the venturi unit;
A pump device for an automatic transmission comprising:
The automatic transmission pump device according to claim 1,
The pump housing has a pump housing main body having the pump element accommodating portion, and a venturi forming block which is a member different from the pump housing main body and joined to the pump housing main body,
The venturi portion is formed in the venturi forming block,
The venturi forming block is a pump device for an automatic transmission that is joined to the pump housing body after the venturi portion is formed.
The automatic transmission pump device according to claim 2,
The pump housing body is made of a metal material,
The venturi forming block is formed of a resin material,
The venturi section is a pump device for an automatic transmission formed by molding.
The automatic transmission pump device according to claim 2,
The pump housing body is made of a metal material,
The venturi forming block is formed of a sintered material;
The venturi section is a pump device for an automatic transmission that is formed by a mold in a compacting process.
The automatic transmission pump device according to claim 2,
The automatic transmission pump device, wherein the small-diameter portion of the venturi portion is formed to open on an outer surface of the venturi forming block.
The automatic transmission pump device according to claim 1,
The venturi portion is a pump device for an automatic transmission provided so that a longitudinal direction of the venturi portion and a direction of a rotation shaft of the drive shaft are substantially orthogonal to each other.
The automatic transmission pump device according to claim 6,
The venturi portion is provided at a position that does not overlap the suction port on a cross section orthogonal to the rotation axis of the drive shaft and a position that overlaps the suction port in the direction of the rotation shaft of the drive shaft. Pump device for automatic transmission.
The automatic transmission pump device according to claim 6,
The venturi section is a pump device for an automatic transmission provided so that a longitudinal direction of the venturi section and a longitudinal direction of the control valve are substantially parallel to each other.
A pump device for an automatic transmission according to claim 8,
The control valve includes a high pressure chamber into which upstream pressure of the venturi portion is introduced, and an intermediate pressure chamber into which pressure in the venturi portion is introduced,
The venturi section is an automatic transmission pump device arranged such that an upstream side of the venturi section faces the high pressure chamber of the control valve.
The automatic transmission pump device according to claim 1,
The venturi unit is an automatic transmission pump device provided so that a longitudinal direction of the venturi unit and a direction of a rotation shaft of the drive shaft are substantially parallel to each other.
A pump device for an automatic transmission according to claim 10,
The venturi portion is located radially outside the pump element housing portion in the radial direction with respect to the rotation shaft of the drive shaft, and overlaps the pump element housing portion in the direction of the rotation shaft of the drive shaft. A pump device for an automatic transmission provided at a position.
The automatic transmission pump device according to claim 1,
The venturi portion is an opening provided on the small diameter portion side of the inner diameter gradually increasing portion in the longitudinal direction of the small diameter portion or the venturi portion, and includes an opening for supplying hydraulic fluid in the venturi portion to the control valve. ,
The automatic transmission pump device is provided with a plurality of openings in a direction around an axis along the longitudinal direction of the venturi.
The automatic transmission pump device according to claim 1,
The venturi section is a pump device for an automatic transmission formed such that a narrow angle sandwiched between inner walls of the inner diameter gradually increasing section is 60 degrees or less.
A pump device for an automatic transmission according to claim 13,
When the inner diameter gradually increasing portion is formed so that the narrow angle between the inner walls of the inner diameter gradually increasing portion is constant and the inner diameter is the same as the inner diameter of the discharge passage from the discharge port to the venturi portion. When the length in the longitudinal direction of the inner diameter gradually increasing portion is L, the inner diameter gradually increasing portion has a narrow angle sandwiched between inner walls of the inner diameter gradually increasing portion that remains constant at 60 degrees or less, and the length in the longitudinal direction is the L And a rear portion provided downstream of the front portion and formed so that the narrow angle is greater than 60 degrees.
The automatic transmission pump device according to claim 1,
The control valve or the venturi section is a pump device for an automatic transmission provided in a housing separate from the pump housing.
The automatic transmission pump device according to claim 1,
The venturi portion is an opening provided in the small-diameter portion, and has an opening for supplying hydraulic fluid in the venturi portion to the control valve.
The automatic transmission pump device according to claim 1,
The pump element is a pump element for a fixed displacement pump having a constant discharge amount per one rotation of the drive shaft,
The control valve is a pump device for an automatic transmission that switches a flow path of the hydraulic fluid so that the hydraulic fluid introduced from the upstream side of the venturi is returned to the suction port side.
The automatic transmission pump device according to claim 1,
The pump element is
A rotor having a plurality of slits in the circumferential direction;
A vane provided so as to freely appear and disappear in the slit of the rotor;
A cam ring which is movably provided in the pump element accommodating portion, is formed in an annular shape, and forms a plurality of pump chambers together with the rotor and the vane;
A pair of spaces formed between the cam ring and the pump element housing portion, the first fluid pressure chamber provided on the side where the volume decreases when the eccentric amount of the cam ring with respect to the rotor increases; and A second fluid pressure chamber provided on the side where the volume increases,
With
A pump element for a variable displacement pump in which a discharge amount per one rotation of the drive shaft is variably controlled;
The control valve is a pump device for an automatic transmission that switches a flow path of hydraulic fluid so that hydraulic fluid introduced from an upstream side of the venturi section is introduced into the first fluid pressure chamber.
A pump device,
A pump housing having a pump element housing;
A drive shaft pivotally supported by the pump housing;
A pump element that is provided in the pump element housing and is rotationally driven by the drive shaft and forms a plurality of pump chambers around the drive shaft;
A suction port formed in the pump housing and opening to a suction region in which the volume of the plurality of pump chambers increases with rotation of the drive shaft;
A discharge port that is formed in the pump housing and opens to a discharge region in which the volume of the plurality of pump chambers decreases as the drive shaft rotates;
A discharge passage connected to the discharge port;
A venturi portion provided in the middle of the discharge passage, a small diameter portion having an inner diameter smaller than the inner diameter of the discharge passage from the discharge port to the venturi portion, and from the small diameter portion to the downstream side of the discharge passage A venturi section having an inner diameter gradually increasing portion formed so that the inner diameter gradually increases toward the inner surface,
A spool valve body that is controlled based on a differential pressure between the hydraulic fluid upstream of the venturi portion and the hydraulic fluid upstream of the venturi portion and the hydraulic fluid in the small diameter portion; A control valve for controlling the flow rate of the hydraulic fluid supplied to the on-vehicle equipment by switching the flow path of the hydraulic fluid introduced from the upstream side of the venturi section;
A pump device comprising: