WO2018150871A1

WO2018150871A1 - Variable displacement oil pump

Info

Publication number: WO2018150871A1
Application number: PCT/JP2018/003077
Authority: WO
Inventors: 浩二佐賀; 大西　秀明
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2017-02-17
Filing date: 2018-01-31
Publication date: 2018-08-23
Also published as: CN110300851A; JP2021167606A; JPWO2018150871A1

Abstract

This variable displacement oil pump is provided with: a rotor (6) disposed within a pump containing chamber (3); a cam ring (5), the amount of eccentricity of which relative to the center of rotation of the rotor changes within the pump containing chamber; a first piston section (25) provided integrally with the outer periphery of the cam ring and located on the side of the cam ring which is opposite the side pressed by a coil spring (31); a first control oil chamber (21) which is formed in the inner periphery of the pump body (2) so that the first piston section can slide thereon, and into which oil pressure is introduced through a discharge passage (23) and a branch passage (24); a first seal member (28) held in a first seal groove (27) formed in the surface (25b) of one side of the first piston section and sealing against the inner wall surface of the first control oil chamber. As a result, the leakage of discharge pressure to the control oil chamber is prevented to obtain desired pump discharge pressure and flow rate characteristics.

Description

Variable displacement oil pump

The present invention relates to a variable displacement oil pump.

In recent years, a variable displacement oil pump described in Patent Document 1 below is known as an oil pump for improving the fuel efficiency of an internal combustion engine for automobiles.

In this variable displacement oil pump, hydraulic pressure is introduced into one of two control oil chambers provided between the inner peripheral surface of the pump housing and the outer peripheral surface of the cam ring from a main oil gallery lower than the pump discharge pressure. The The other control oil chamber is introduced with a lower hydraulic pressure of the main oil gallery. By controlling the oil pressure into each control oil chamber, the eccentric amount of the cam ring is moved in the direction of increasing or decreasing to control the pump discharge pressure.

International publication WO2014 / 187503 A1

However, a high hydraulic pressure of the discharge port acts on one side of the outer periphery of the cam ring, and a low hydraulic pressure of the suction port acts on the other side. For this reason, the cam ring is pressed against the other side by the high hydraulic pressure on the one discharge port side, and there is a possibility that the gap between the housing constituting the one control oil chamber and the cam ring becomes large.

Then, the pump discharge pressure may enter one of the control oil chambers from the gap (leak), and the cam ring behavior may become unstable.

As a result, there is a possibility that desired discharge pressure and flow rate characteristics by the variable displacement oil pump cannot be obtained.

An object of the present invention is to provide a variable displacement oil pump that suppresses leakage of discharge pressure to a control oil chamber and obtains desired pump discharge pressure and flow rate characteristics.

As a preferred aspect of the present invention, a cam ring in which an eccentric amount between the rotation center of the rotor and the center of the rotor changes linearly by moving in a housing portion of the housing, and a direction in which the eccentric amount of the rotor and the cam ring increases. A biasing member that applies a biasing force to the cam ring, and a piston portion that is integrally provided on the outer periphery of the cam ring and that is provided at a position opposite to the biasing direction of the biasing member with respect to the cam ring. A control oil chamber in which oil is introduced from a main oil gallery in which the piston portion is slidably formed on the inner periphery of the housing and supplies lubricating oil to the sliding portion of the internal combustion engine; the piston portion; A sealing member provided at a position on the discharge portion side, which is a sliding surface with the inner wall surface of the control oil chamber.

According to one aspect of the present invention, it is possible to obtain the desired pump discharge pressure and flow rate characteristics by suppressing the leakage of the discharge pressure to the control oil chamber.

It is a schematic diagram of the variable displacement oil pump in the first embodiment. It is a disassembled perspective view of the cam ring and seal member which are provided to this embodiment. It is the A section enlarged view of FIG. FIG. 2 is a sectional view taken along line BB in FIG. FIG. 2 is a cross-sectional view taken along the line CC of FIG. It is a schematic diagram explaining the action | operation of the variable displacement type oil pump in this embodiment. It is a schematic diagram explaining the action | operation of the variable displacement type oil pump in this embodiment. It is a characteristic view which shows the relationship between the engine speed of the variable displacement type oil pump of this embodiment, and pump discharge pressure. It is a characteristic view which shows the relationship between the engine speed of the variable displacement type oil pump of this embodiment, and pump discharge pressure. It is a characteristic view which shows the relationship between the engine speed of the variable displacement type oil pump of this embodiment, and pump discharge pressure. It is a schematic diagram of the variable displacement oil pump in the second embodiment of the present invention. It is a disassembled perspective view of the cam ring and seal member which are provided to this embodiment. It is the D section enlarged view of FIG. FIG. 12 is a cross-sectional view taken along the line EE of FIG. FIG. 12 is a sectional view taken along line FF in FIG. 11. It is a schematic diagram of the variable displacement oil pump in the third embodiment of the present invention. It is a disassembled perspective view of the cam ring and seal member which are provided to this embodiment. It is the G section enlarged view of FIG. FIG. 12 is a cross-sectional view taken along line HH in FIG. 11. It is the II sectional view taken on the line of FIG.

Hereinafter, embodiments of a variable displacement oil pump according to the present invention will be described in detail with reference to the drawings. In the following embodiments, the present invention is applied to a variable displacement oil pump that supplies engine lubricating oil to a valve timing control device that is used to control the opening / closing timing of sliding parts and engine valves of an internal combustion engine for automobiles. ing.
[First Embodiment]
1 is a schematic diagram of a variable displacement oil pump according to the present embodiment, FIG. 2 is an exploded perspective view of a cam ring and a seal member provided for the present embodiment, FIG. 3 is an enlarged view of a portion A in FIG. 1 is a cross-sectional view taken along line BB of FIG. 1, and FIG. 5 is a cross-sectional view taken along line CC of FIG.

As shown in FIG. 1, the variable displacement oil pump includes a pump housing 1 and a drive shaft 4 that is rotatably supported through a central portion of a pump housing chamber 3 as a pump housing portion in the pump housing 1. And a cam ring 5 accommodated in the pump accommodating chamber 3 so as to be linearly movable, and a pump structure accommodated inside the cam ring 5.

The pump structure is driven to rotate in the counterclockwise direction in FIG. 1 by the drive shaft 4, thereby increasing or decreasing the volume of the pump chamber 13 that is a working chamber formed between the pump ring body and the cam ring 5. It is like that.

The pump housing 1 is provided, for example, at a front end portion of a cylinder block (not shown) of the internal combustion engine 19, and as shown in FIG. 1, a pump body 2 having an opening formed at one end side and the pump housing chamber 3 provided therein. And a cover member (not shown) that closes one end opening of the pump body 2.

A first control oil chamber 21 and a second control oil chamber 22 which will be described later are provided inside the pump housing 1, and a pilot valve 40 for controlling supply and discharge of hydraulic pressure to the second control oil chamber 22 is provided. It has been. Further, the pilot valve 40 is operated by the electromagnetic force of the electromagnetic actuator 50 in addition to being operated by the hydraulic pressure of the discharge passage 23 as will be described later.

The pump body 2 is integrally formed of an aluminum alloy material that is a non-ferrous metal, and a bearing hole (not shown) that rotatably supports one end portion of the drive shaft 4 is formed at a substantially central position of the bottom wall of the pump housing chamber 3. Has been.

Further, a suction port 11 which is a suction portion formed so as to open to a region where the volume of each pump chamber 13 is expanded in accordance with the pump action by the pump structure is provided on one side portion of the pump housing chamber 3. Yes.

In addition, on the inner side surface of the other side portion, the discharge port 12 which is a discharge portion formed so as to open to a region where the volume of each pump chamber 13 is reduced is opposed to the left and right sides with the bearing hole interposed therebetween. Is provided.

The suction port 11 is formed with a suction passage 11a that passes through the wall of the pump body 2 and communicates with the outside. The oil (lubricating oil) in the oil pan 14 is sucked into the suction passage 11a and the suction port 11 by the negative pressure generated by the pump action of the pump structure. This oil is sucked into each pump chamber 13 in the suction area of the suction port 11.

The discharge port 12 is formed with a discharge passage 12a that passes through the bottom wall of the pump body 2 and communicates with the outside. Then, the oil pressurized by the pump action is discharged to the discharge port 12. The discharged oil is supplied from the main oil gallery 18 into the internal combustion engine 19 through the discharge passage 12a as shown by the arrow in FIG. That is, it is supplied to each sliding part such as a piston of the internal combustion engine 19 and a valve timing control device.

The main oil gallery 18 has a supply passage 18a for supplying lubricating oil into the internal combustion engine 19 and a discharge passage 23 for returning the lubricating oil circulated through the internal combustion engine 19 to the oil pan 14. In the middle of the supply passage 20, an oil filter 49 and an oil cooler (not shown) are provided.

A first control oil chamber 21 is formed on the inner wall surface on one side in the radial direction across the cam ring 5 of the pump body 2, and a second control oil chamber 22 that is a recess is formed on the inner wall surface on the other side. Yes.

The first control oil chamber 21 is formed in a concave shape on the inner wall surface of the pump body 2 and is formed in a substantially square shape in cross section, and a bottom surface 21a is formed in a V shape. Further, the first control oil chamber 21 has a relatively small overall volume, and a downstream portion 23b of a branch passage 24 branched at a downstream side of a discharge passage 23 described later is opened at an end portion 21a. The second control oil chamber 22 is formed in a concave shape at a position facing the first control oil chamber 21 of the pump body 2 and the pump storage chamber 3 in the radial direction, and has a substantially square cross section. The entire volume of the second control oil chamber 22 is larger than that of the first control oil chamber 21, and the bottom side communicates with the pilot valve 40.

Further, the oil after lubricating the sliding portions in the internal combustion engine 19 and the like is supplied to the first and second

control oil chambers

22 and 22 through the discharge passage 23. That is, in the discharge passage 23, the upstream portion 23 a communicates with the drain passage of the internal combustion engine 19, and the downstream portion 23 b communicates with the second control oil chamber 22 via the pilot valve 40. Further, a branch passage 24 is formed which branches on the downstream side of the discharge passage 23. The branch passage 24 has a downstream end 24 a that opens to the end 21 a of the first control oil chamber 21.

Since the oil in the discharge passage 23 is returned through the oil filter 49 and the sliding portions of the internal combustion engine 19, the oil pressure (pump discharge pressure) of the supply passage 20 is caused by the flow resistance and the like. ) Is lower than. Further, the pulse pressure of this oil is sufficiently reduced due to the aforementioned flow resistance and the like.

The cover member (not shown) is formed in a substantially plate shape from a non-ferrous metal aluminum alloy material, and is formed in a rectangular shape that is long in the vertical direction following the outer shape of the pump body 2. Further, the outer peripheral side of the inner surface of the cover member is attached to the mounting surface of the pump body 2 on the opening side of the pump housing chamber 3 by a plurality of bolts not shown. Further, a bearing hole that rotatably supports the other end of the drive shaft 4 is formed through the cover member at a position facing the bearing hole of the pump body 2. Further, on the inner surface of the cover member, similarly to the pump body 2, the suction port and the discharge port are disposed so as to face the suction port 11 and the discharge port 12 of the pump body 2. The suction port 11 and the discharge port 12 may be formed on either the pump body 2 side or the cover member side.

The drive shaft 4 is supported at one end in the direction of the rotation axis by a bearing hole in the bottom wall of the pump body 2 and at the other end by a bearing hole in the cover member. Further, the drive shaft 4 has a tip end facing the outside linked to the crankshaft via a gear (not shown). Based on the rotational force transmitted from the crankshaft, the drive shaft 4 rotates a rotor 6 described later in the counterclockwise direction in FIG.

The pump structure is rotatably accommodated on the inner peripheral side of the cam ring 5, and a rotor 6 having a central portion coupled to the outer periphery of the drive shaft 4, and a plurality of (this book) radially formed in the outer peripheral portion of the rotor 6. In this embodiment, seven vanes 7 are housed in a slot 6a so as to be able to move in and out, and a pair of rotors 6 are formed with a smaller diameter than the rotor 6 and are disposed on both sides of the rotor 6 in the rotation axis direction. And

ring members

8 and 8.

A chamber 6b having a substantially circular cross section is provided in each of the inner base end portions of the seven slots 6a formed radially outward from the center side of the rotor 6 so as to introduce discharge oil as hydraulic oil. . The chamber 6 b is pushed outward so that the vanes 7 are in sliding contact with the inner surface of the cam ring 5 by the internal pressure and the centrifugal force accompanying the rotation of the rotor 6.

Each vane 7 is configured such that, when the rotor 6 rotates, each distal end surface is in sliding contact with the inner peripheral surface of the cam ring 5, and each proximal end surface is in sliding contact with the outer peripheral surface of each of the

ring members

8, 8. .

As shown in FIGS. 1 and 2, the cam ring 5 is integrally formed in a substantially cylindrical shape by ferrous metal by a sintering method. The cam ring 5 has a width in the axial direction, that is, a length along the rotational axis direction of the drive shaft 4 such that the cam ring 5 can slide with a small gap between the bottom surface of the pump housing chamber 3 and the facing surface of the cover member. Is formed.

The cam ring 5 is formed with substantially arc-shaped

cutout grooves

5a and 5b on the axial end surfaces of the suction port 11 side and the discharge port 12 side, respectively.

Further, a first piston portion 25 slidably accommodated in the first control oil chamber 21 is integrally provided at one position (right side in FIG. 1) of the outer peripheral portion of the cam ring 5. Further, the second piston part slidably accommodated in the second control oil chamber 22 at the other position (left side in FIG. 1) opposite to the first piston part 25 across the center of the cam ring 5. 26 is provided integrally.

The first piston portion 25 is formed in a substantially rectangular cross section following the cross sectional shape of the first control oil chamber 21. That is, the cross section in the direction orthogonal to the moving direction axis of the cam ring 5 is formed in a quadrangle. The first piston portion 25 is formed such that the length along the rotation axis direction of the drive shaft 4 is the same as the axial width of the cam ring 5.

Also, the first piston portion 25 has a tip surface 25a formed in a substantially V shape, like the V-shaped bottom surface 21a of the first control oil chamber 21. The front end surface 25 a is a pressure receiving surface that faces the first control oil chamber 21 and receives the hydraulic pressure in the first control oil chamber 21.

And in the position where the 1st piston part 25 entered the maximum in the 1st control oil chamber 21, the front-end | tip surface 25a whole contact | abuts to the bottom face 21a, and the further linear movement of the cam ring 5 comes to be controlled. ing.

Also, the first piston portion 25 has a first seal groove 27 formed on a surface 25b on one side of the four sides, that is, on the side where the downstream end 24a of the branch passage 24 opens. As shown in FIGS. 2 and 3, the first seal groove 27 is formed in a substantially quadrangular cross section and is linear with the same length as the axial direction of the cam ring 5 of the side surface 25 b. Is formed.

The first seal member 28 is held in the first seal groove 27. The first seal member 28 is held in a first seal body 28 a that slides on the inner wall surface of the first control oil chamber 21 and the bottom of the first seal groove 27, and the first seal body 28 a And a first elastic body 28b that urges the control oil chamber 21 toward the inner wall surface.

The first seal body 28a is formed in a substantially rectangular shape in cross section, and is formed in a linear shape along the axial direction of the cam ring 5 with, for example, a fluorine-based resin material having low friction characteristics. In addition, a holding groove 28c into which a part of the first elastic body 28b is fitted is linearly formed at the center position in the width direction of the first seal body 28a.

The first elastic body 28b is formed of a synthetic rubber material in a substantially circular cross section, and has the same length as the first seal body 28a. The first seal body 28a is pressed against the inner wall surface of the first control oil chamber 21 by the elastic force of the first elastic body 28b to ensure good liquid tightness of the first control oil chamber 21.

The second piston portion 26 is formed in a substantially U-shaped cross section and has a base portion 26a coupled to the cam ring 5 and a side wall 26b extending outward from one end side of the base portion 26a along the moving direction of the cam ring 5. And another side wall 26c extending in parallel with the one side wall 26b from the other end side of the base portion 26a.

The one side wall 26b and the other side wall 26c are formed to have the same length as that of the first piston portion 25 in the cam ring 5 axis direction. The

side walls

26 b and 26 c are slidable on the opposite side surfaces 22 a and 22 b of the second control oil chamber 22, respectively. Further, the entire inner surface 26 f surrounded by the base portion 26 a and both

side walls

26 b and 26 c is a pressure receiving surface that receives the hydraulic pressure in the second control oil chamber 22. Therefore, the pressure receiving area of the entire inner surface 26f is formed larger than the pressure receiving area of the front end surface 25a of the first piston portion 25.

The one side wall 26 b is formed at the same position on the radially outer side in the moving direction of the first piston portion 25 and the cam ring 5. A second seal groove 29 is formed on the outer surface 26d of the one side wall 26b. As shown in FIG. 2, the second seal groove 29 is formed in a substantially square shape in cross section, and the length is the same as the axial length of the cam ring 5 of the one side wall 26b.

In the second seal groove 29, a second seal member 30 having the same configuration as the first seal member 28 is held. That is, the second seal member 30 is held in the second seal body 30a that slides on the inner wall surface of the second control oil chamber 22 and the bottom of the second seal groove 29, and the second seal body 30a is held in the second position. And a second elastic body 30b that urges the control oil chamber 22 toward the inner wall surface.

The second seal main body 30a is formed in a substantially rectangular shape in cross section, and is formed in a linear shape along the axial direction of the cam ring 5 with a fluorine-based resin material having low friction characteristics, for example. The second elastic body 30b is formed of a synthetic rubber material in a substantially circular cross section and has the same length as the second seal body 30a. The second seal body 30a is pressed against the opposing inner surface of the second control oil chamber 22 by the elastic force of the second elastic body 30b to ensure good liquid tightness of the second control oil chamber 22. ing.

Further, as shown in FIG. 1, a coil spring 31 that urges the cam ring 5 toward the first control oil chamber 21 via the second piston portion 26 is accommodated in the second control oil chamber 22.

The coil spring 31 has one end elastically contacted with the inner surface of the base portion 26a of the second piston portion 26 and the other end elastically contacted with an outer surface of a valve body 41 (to be described later) of the pilot valve 40. Yes.

As described above, the cam ring 5 is always applied in the direction in which the amount of eccentricity in the direction of the first control oil chamber 21 increases with respect to the rotation center of the rotor 6 by the urging force of the coil spring 31 (right direction in FIG. 1). It is energized. Therefore, in the non-operating state, the V-shaped tip surface 25 a of the first piston portion 25 is pressed against the V-shaped bottom surface 21 a of the first control oil chamber 21. In this state, the cam ring 5 is restricted to a position where the center eccentricity is maximized.

The cam ring 5 has a relative pressure between the hydraulic pressure introduced into the first control oil chamber 21 and the hydraulic pressure introduced into the second control oil chamber 22 and the spring load of the coil spring 31 with respect to the rotation center of the rotor 6. To move straight. That is, the cam ring 5 moves in a direction in which the amount of eccentricity with respect to the rotation center of the rotor 6 increases or decreases, thereby controlling the discharge pressure and the discharge flow rate discharged from the discharge port 12.

As shown in FIG. 1, the pilot valve 40 includes a covered cylindrical valve body 41 fixed in the valve hole 1 a of the pump housing 1, and a spool 42 slidably provided inside the valve body 41. The spool 42 is mainly composed of a valve spring 43 as a biasing member that biases the spool 42 in the direction of the annular wall 41a described later.

In the valve body 41, an annular wall 41a on one end side in the axial direction is formed with an introduction port 41b that communicates the downstream end of the discharge passage 23 with the inside. Further, the valve body 41 has a communication hole 44 penetrating in the radial direction that communicates the inside of the valve body 41 and the second control oil chamber 22 at a substantially central position in the axial direction of the peripheral wall.

Further, a drain hole 45 that communicates the inside and the outside of the valve body 41 is formed along the radial direction at a position opposite to the communication hole 44 in the radial direction with respect to the central axis of the peripheral wall of the valve body 41. . In the vicinity of the drain hole 45, an air vent hole 41c that ensures good slidability of the spool 42 is formed penetrating along the radial direction.

The spool 42 communicates with the communication hole 44 and the drain hole 45 in accordance with the sliding position, or has a closed cylindrical valve body 46 that restricts the communication, and is integrally formed on one end of the valve body 46 in the axial direction. The passage component 47 is formed to have a hollow inner shape, and an annular plate-shaped guide portion 48 formed integrally with one end edge in the axial direction of the channel component 47.

The valve body 46 is formed in a cylindrical shape whose outer peripheral surface slides liquid-tightly on the inner peripheral surface of the valve body 41 and exerts a valve function. Further, the valve body 46 is integrally provided with a disk wall 46a on one end side in the axial direction, that is, on one end side on the passage component 47 side. The disc wall 46 a also functions as a pressure receiving portion that receives the hydraulic pressure introduced into a passage portion 47 b (described later) of the passage constitution portion 47.

The passage constituting portion 47 is formed in a cylindrical shape extending in the axial direction from the disc wall 46 a toward the introduction port 41 b, and has an outer diameter smaller than that of the valve body 46. Further, a cylindrical passage 47 a is formed on the outer peripheral surface of the passage constituting portion 47 between the inner peripheral surface of the valve body 41.

Furthermore, a cylindrical passage portion 47b that always communicates with the introduction port 41b through an opening portion 47d formed on one end side in the axial direction is formed inside the passage constitution portion 47. A second communication hole 47c that communicates the communication hole 44 of the passage portion 47b and the valve body 41 via the cylindrical passage 47a is formed in the peripheral wall of the passage configuration portion 47 along the radial direction.

Therefore, the passage portion 47b is appropriately communicated with the second control oil chamber 22 through the second communication hole 47c, the cylindrical passage 47a, and the communication hole 44 according to the sliding position of the spool 42.

The guide portion 48 slides on the inner peripheral surface of the valve body 41 so that the guide portion 48 cooperates with the valve body 46 when the spool 42 slides to ensure stable slidability in the axial direction. It has become.

The valve spring 43 is elastically mounted between the inner end surface of the disc wall 46a and the bottom of the valve body 41, and always urges the entire spool 42 in the direction of the annular wall 41a. As shown in FIG. 1, the valve body 46 closes the drain hole 45 at the moving position where the guide portion 48 is in elastic contact with the inner surface of the annular wall 41 a by the biasing force of the valve spring 43 as shown in FIG. 1. It has become.

Therefore, the spool 42 basically changes the moving position in the axial direction based on the relative pressure between the spring force of the valve spring 43 and the hydraulic pressure introduced from the discharge passage 23 to the introduction port 41b. .

The electromagnetic actuator 50 controls the moving position of the spool 42 in such a way as to assist the hydraulic pressure from the discharge passage 23. The electromagnetic actuator 50 includes a solenoid casing (not shown), a coil provided inside the solenoid casing via a bobbin, a fixed iron core provided at an axial end of the coil, and an inner peripheral side of the bobbin. A movable plunger provided so as to be slidable in the axial direction, and a push rod provided at the tip of the movable plunger and pressing the spool 42 from the same axial direction as the hydraulic action direction from the discharge passage 23. Has been.

The movable plunger moves forward by energization (pulse current) to the coil output from the control unit, and moves backward by the spring force of the coil spring when not energized.

The control unit detects the engine operating state based on information signals from various sensors such as a crank angle sensor. Further, the control unit is configured to change the duty ratio, which is the energization amount to the coil of the electromagnetic actuator 50, according to the engine operation state, or to be in a non-energized state.
[Operation of variable displacement oil pump]
Hereinafter, the operation of the variable displacement oil pump according to the present embodiment will be briefly described. 6 shows a state in which the hydraulic pressure of the discharge passage 23 and the pressing force of the electromagnetic actuator are applied to the pilot valve 40, and FIG. 7 shows a state in which only the pressure of the discharge passage 23 is applied to the pilot valve 40. 8 to 10 are characteristic diagrams showing the relationship between the engine speed (pump speed) and the pump discharge pressure.

When the engine is started, the pump discharge pressure pumped from the discharge port 12 of the variable displacement oil pump to the discharge passage 12a is low. Therefore, after lubricating the sliding portion such as the valve mechanism in the engine 19 from the supply passage 20 of the main oil gallery 18, the hydraulic pressure flowing into the passage portion 47b from the introduction port 41b of the pilot valve 40 from the discharge passage 23 is also low. For this reason, the hydraulic pressure acting on the disk wall 46a in the passage portion 47b is also small.

Therefore, as shown in FIG. 1, the spool 42 is held at a position where the guide portion 48 abuts against the inner surface of the annular wall 41a by the spring force of the valve spring 43. Therefore, the valve body 46 closes the drain hole 45 although the communication hole 44 is opened on the outer peripheral surface.

Thus, the hydraulic pressure that has flowed into the passage portion 47b flows into the second control oil chamber 22 through the second communication hole 47c, the cylindrical passage 47a, and the communication hole 44, as indicated by arrows.

On the other hand, the hydraulic pressure flowing into the branch passage 24 from the discharge passage 23 flows into the first control oil chamber 21 from the downstream end 24 a of the branch passage 24. The oil pressure in the first control oil chamber 21 is the same as the oil pressure in the second control oil chamber 22. Accordingly, the pressure acting on the first piston portion 25 and the second piston portion 26 is the same, and the same pressure directed toward the center of the cam ring 5 acts on both sides of the cam ring 5. However, since the pressure receiving area of the front end surface 25 a of the first piston portion 25 is smaller than the pressure receiving area of the second piston portion 26, a force in the direction of the first control oil chamber 21 is increased with respect to the cam ring 5.

Therefore, as shown in FIG. 1, the cam ring 5 moves in the direction of the first control oil chamber 21 with respect to the rotation axis center of the rotor 6 by the combined force of the hydraulic pressure in the second control oil chamber 22 and the spring force of the coil spring 31. It is held in the position of maximum eccentricity.

At this time, the coil of the electromagnetic actuator 50 is deenergized without being energized from the control unit.

Therefore, the pump discharge pressure (hydraulic pressure in the supply passage 20) discharged from the discharge port 12 increases in proportion to the engine speed as the engine speed increases, as shown by the solid line in FIG. It becomes a characteristic.

When the pump discharge pressure gradually increases to a desired level, as shown in FIG. 6, in addition to the hydraulic pressure from the discharge passage 23, the pressing force of the electromagnetic actuator 50 acts on the pilot valve 40. .

That is, energization (pulse signal) is output from the control unit to the coil of the electromagnetic actuator 50, and the duty ratio is appropriately changed. Accordingly, the spool 42 of the pilot valve 40 gradually slides toward the bottom of the valve body 41 against the spring force of the valve spring 43. Then, the valve body 46 of the spool 42 gradually opens the drain hole 45 while maintaining the state where the communication hole 44 is opened, and the hydraulic pressure in the second control oil chamber 22 is supplied via the communication hole 44 and the cylindrical passage 47a. It is discharged from the drain hole 45 to the outside.

During this time, the first control oil chamber 21 is always supplied with hydraulic pressure from the discharge passage 23 via the branch passage 24, but this hydraulic pressure may be low.

The sliding position of the spool 42 is changed by the duty ratio control from the control unit to the electromagnetic actuator 50 to control the opening / closing of the drain hole 45 and to increase / decrease the opening area. For this reason, the hydraulic pressure in the second control oil chamber 22 changes.

Therefore, relative pressure between the hydraulic pressure in the first control oil chamber 21 and the changing hydraulic pressure in the second control oil chamber 22 and the spring force of the coil spring 31 acts on the cam ring 5. That is, when the hydraulic pressure in the first control oil chamber 21 becomes larger than the combined force of the hydraulic pressure in the second control oil chamber 22 and the coil spring 31, the cam ring 5 linearly moves toward the second control oil chamber 22. Moving. As a result, the cam ring 5 has a small eccentric amount with respect to the center of rotation of the rotor 6.

As described above, the cam ring 5 is linearly moved between the

control oil chambers

21 and 22 so that the pump discharge pressure is variably controlled in accordance with the engine speed as shown by the solid line in FIG. Is possible.

Next, the pump discharge pressure from the discharge port 12 increases, and the hydraulic pressure acting on the disk wall 46a of the spool 42 of the pilot valve 40 from the discharge passage 23 increases. Then, the spool 42 slides toward the bottom of the valve body 41 against the spring force of the valve spring 43, as shown in FIG.

For this reason, the hydraulic pressure in the second control oil chamber 22 is discharged from the drain hole 45 through the communication hole 44 and the cylindrical passage 47a as described above, and the inside becomes a low pressure. On the other hand, high hydraulic pressure is introduced into the first control oil chamber 21 from the branch passage 24, pressing the first piston portion 25, and moving the cam ring 5 toward the second control oil chamber 22. As a result, the cam ring 5 has a small amount of eccentricity with respect to the rotation center of the rotor 6 and becomes close to the concentricity. Therefore, as shown by the solid line in FIG. 10, the pump discharge pressure becomes a size in the vicinity of the maximum, and an excessive pressure increase is further suppressed.

As described above, the variable displacement oil pump according to the present embodiment controls the sliding position of the spool 42 of the pilot valve 40 by the hydraulic pressure of the discharge passage 23 and the solenoid force of the electromagnetic actuator 50, thereby controlling the second control oil chamber 22. Control the hydraulic pressure inside. As a result, the movement position of the cam ring 5 in the linear direction can be continuously variably controlled, and the pump discharge pressure can be controlled with high accuracy in accordance with the engine operating state.

In the present embodiment, the space between the inner surface of the first control oil chamber 21 located on the discharge port 12 side and the surface 25 b on one side of the first piston portion 25 is effectively sealed by the first seal member 28. Yes.

For this reason, it becomes possible to sufficiently suppress the high hydraulic pressure on the discharge port 12 side (discharge region) from flowing into the first control oil chamber 21 (leakage). Therefore, the cam ring 5 can be held in a stable position with the behavior unstable. As a result, a desired stable discharge pressure and flow rate characteristic of the pump discharge pressure can be obtained.

In addition, in the discharge passage 23, not the oil pressure of the supply passage 20 where substantially the same oil pressure as the pump discharge pressure is applied, but the oil pressure in which the pulse pressure is sufficiently suppressed through the oil filter 49, the sliding portion inside the engine 19, etc. Flows in.

For this reason, since a low hydraulic pressure acts on the passage portion 47b of the spool 42, a stable hydraulic pressure always acts on the disk wall 46a. Therefore, the holding position and the sliding position of the spool 42 are stabilized, and the accuracy of supply and discharge of the hydraulic pressure in the second control oil chamber 22 is increased. As a result, since the linear movement of the cam ring 5 and the stabilization of the movement position can be achieved, the above-described pump discharge pressure and characteristics can be controlled with higher accuracy.

In addition, since the balanced pressure of the stable hydraulic pressure in which the pulse pressure of the discharge passage 23 is suppressed and the solenoid force of the electromagnetic actuator 50 acts on the spool 42, the stable sliding position of the spool 42 also in this respect. Control can be performed.

In the present embodiment, the second seal member 30 also effectively provides a space between the inner wall surface of the second control oil chamber 22 located on the discharge port 12 side and the outer surface 26d of the one side wall 26b of the second piston portion 26. It is sealed. For this reason, it is possible to sufficiently suppress the high hydraulic pressure on the discharge port 12 side from flowing (leaking) into the second control oil chamber 22. Accordingly, the cam ring 5 is held in a stable position with the behavioral instability being suppressed also in this respect. As a result, more stable discharge pressure and flow rate characteristics of the pump can be obtained.

Since the first and

second seal members

28 and 30 seal only the portions facing the discharge port 12 side of the

piston portions

25 and 26, the first and

second seal members

28 and 30 can be efficiently sealed.

Further, since the first seal member 28 and the second seal member 30 are pressed against the opposing surfaces of the first control oil chamber 21 and the second control oil chamber 22 in a surface contact state, the sealing performance is improved. Oil leakage from the discharge port 12 side to the

control oil chambers

21 and 22 can be minimized.

The oil leakage from the discharge port 12 side can be suppressed only by the first and

second seal members

28 and 30, and the structure is simplified because only these two members are used.

Further, since the first seal member 28 and the second seal member 30 are formed by simply forming the

seal bodies

28a, 30a and the

elastic bodies

28b, 30b in a straight line, the manufacture is easy and the increase in cost is suppressed. it can.

Furthermore, since each

seal body

28a, 30a is held in each

seal groove

27, 29, it is possible to suppress the displacement of each

piston portion

25, 26 during sliding.

The

seal bodies

28a and 30a are made of a material harder than the

elastic bodies

28b and 30b. However, if these materials are changed according to the specifications, the sliding resistance friction can be reduced and the durability can be improved. Improvement can be achieved.

In the present embodiment, the first piston portion 25 is provided on one side of the cam ring 5 in the linear movement direction, and the second piston portion 26 is provided on the other side opposite thereto. As a result, stable movement guidance of the cam ring 5 is performed.

Since the coil spring 31 is disposed on the inner side of the second piston portion 26, the pump housing 1 can be reduced in size as compared with the case where it is provided elsewhere.

A pressure lower than the pump discharge pressure is applied from the discharge passage 23 to the inside of the second piston portion 26. For this reason, high hydraulic pressure from the discharge port 12 side easily enters the second control oil chamber 22, but this can be effectively suppressed by the second seal member 30.
[Second Embodiment]
11 to 15 show a second embodiment of the present invention, FIG. 11 is a schematic view of a variable displacement oil pump according to the second embodiment, and FIG. 12 is an exploded perspective view of a cam ring and a seal member used in this embodiment. 13 is an enlarged view of a portion D in FIG. 11, FIG. 14 is a cross-sectional view taken along line EE in FIG. 11, and FIG. 15 is a cross-sectional view taken along line FF in FIG.

In this embodiment, in particular, the shape of the second piston portion 26 is slightly changed, and the configurations of the first and second seal grooves and the first and second seal members are changed.

That is, as shown in FIG. 12, the second piston portion 26 is formed such that the thickness of the base portion 26a is slightly larger than that of the first embodiment.

In addition to the one side surface 25b side of the first piston portion 25, the first seal groove 27 is formed with a third seal groove 32 along the width direction of one side surface 25c continuous with the one side surface 25b. It is formed in an L shape. The first seal groove 27 has the same cross-sectional shape as that of the first embodiment. Further, the first seal member 28 fitted and held in the first seal groove 27 is also composed of a first seal body 28a and a first elastic body 28b.

The third seal groove 32 has the same width and depth as the first seal groove 27.

The third seal member 33 held in the third seal groove 32 is similarly composed of a third seal body 33a and a third elastic body 33b. The third seal body 33a is formed of a fluorine-based resin material having a low friction characteristic like the first seal body 28a. The third seal body 33 a is formed in an elongated plate shape, and the length thereof is set to the same length as the third seal groove 32.

The third elastic body 33b is formed in a substantially circular cross section by a synthetic rubber material, and has the same length as the third seal body 33a. The third seal body 33a is pressed against the opposing inner surface of the second control oil chamber 22 by the elastic force of the third elastic body 33b to ensure good liquid tightness of the second control oil chamber 22. ing. In addition, the opposing edge part of the 1st elastic body 28b and the 3rd elastic body 33b is arrange | positioned in the abutting state from the substantially right angle direction.

On the other hand, in addition to the second seal groove 29, a fourth seal groove 34 is formed on one outer surface 26g in the base part 26a of the second piston part 26. The fourth seal groove 34 is elongated along the width direction of the base portion 26 a, and the depth thereof is the same as that of the second seal groove 29. A fourth seal member 35 is fitted in the fourth seal groove 34.

The fourth seal member 35 includes a fourth seal body 35a and a fourth elastic body 35b. The fourth seal body 35a is formed of the same material as the first seal body 28a. The fourth seal body 35a is formed in an elongated plate shape, and the length thereof is set to the same length as the fourth seal groove 34.

The fourth elastic body 35b is also formed in a substantially circular shape in cross section by a synthetic rubber material, and has the same length as the fourth seal body 35a. The fourth seal body 35a is pressed against the opposing inner surface of the second control oil chamber 22 by the elastic force of the fourth elastic body 35b to ensure good liquid tightness of the second control oil chamber 22. ing. In addition, the opposing edge part of the 2nd elastic body 30b and the 4th elastic body 35b is arrange | positioned in the abutting state from the substantially right angle direction.

Therefore, in addition to the first and

second seal members

28 and 30, the corresponding first control oil chamber 21 and the opposed inner wall surface of the second control oil chamber 22 are formed by the third and

fourth seal members

33 and 35. Seal the gap. For this reason, the inflow of high hydraulic pressure from the discharge port 12 side to the first control oil chamber 21 and the second control oil chamber 22 can be further effectively suppressed.

Other functions and effects are the same as those in the first embodiment.

The first elastic body 28b and the third elastic body 33b, and the second elastic body 30b and the fourth elastic body 35b are opposed to each other in a substantially perpendicular direction. However, as long as an elastic reaction force can be exerted on each of the seal bodies 28a to 35a, it is not always necessary to have a butt shape, and the seal bodies 28a to 35a may be separated from each other.
[Third Embodiment]
16 to 20 show a third embodiment of the present invention, FIG. 16 is a schematic view of a variable displacement oil pump according to the third embodiment, and FIG. 17 is an exploded perspective view of a cam ring and a seal member used in this embodiment. 18, FIG. 18 is an enlarged view of a portion G in FIG. 16, FIG. 19 is a sectional view taken along line HH in FIG. 16, and FIG. 20 is a sectional view taken along line II in FIG.

In this embodiment, the first seal groove 27 to the fourth seal groove 34 shown in the second embodiment are formed at the same depth as the

seal grooves

27 and 29 shown in the first embodiment. Accordingly, the first seal groove 27 and the third seal groove 32 are formed in an L shape having the same depth. The second seal groove 29 and the fourth seal groove 34 are also formed in an L shape having the same depth.

The first seal member 28 is integrated with the third seal member 33 by joining opposite ends thereof, and is formed into an elongated L-shape as a whole. On the other hand, the second seal member 30 is integrated with the fourth seal member 35 by coupling the opposite end portions, and is also formed in an elongated L-shape.

The first, second, third and fourth seal members 28 to 35 are respectively the first, second, third and fourth seal bodies 28a to 35a and the first, second, third and fourth elastic bodies. 28b to 35b.

The first to fourth seal bodies 28a to 35a are made of a fluorine-based resin material having a low friction characteristic as in the first embodiment. On the other hand, the first to fourth elastic bodies 28b to 35b are also formed in a substantially circular cross section by a synthetic rubber material as in the first embodiment, and have the same length as the seal bodies 28a to 35a. The first to fourth seal bodies 28a to 35a are pressed against the opposing inner side surfaces of the first and second

control oil chambers

21 and 22 by the elastic force of the elastic bodies 28b to 35b. Good fluid tightness of the

oil chambers

21 and 22 is ensured.

For this reason, inflow of high hydraulic pressure from the discharge port 12 side to the first control oil chamber 21 and the second control oil chamber 22 can be further effectively suppressed.

Further, by integrating the

seal members

28, 30, 33, and 35, the manufacturing operation becomes easy. Further, since the

seal grooves

27, 29, 32, and 34 have substantially the same depth, the machining operation is facilitated.

The other functions and effects are the same as those in the first and second embodiments.

Further, the opposing end portions of the first and third

elastic bodies

28b and 33b and the second and fourth

elastic bodies

30b and 35b are also in a butted state.

The present invention is not limited to the configuration of each of the above embodiments. For example, the hydraulic pressure introduced into the pilot valve 40 can be directly introduced not only from the discharge passage 23 but also from the supply passage 20. is there.

Further, the material of each sealing member such as the first and

second sealing members

28 and 30 may be other materials as long as it is a low friction material.

Furthermore, the difference in volume between the first and second

control oil chambers

21 and 22 can be freely changed according to the specification and size of the pump.

Furthermore, it is also possible to form each seal groove on the inner wall surface of each control oil chamber and hold each seal member in each seal groove.

It is also possible to bias a sealing member that does not have an elastic body outwardly by providing an elastic body.

As another preferable aspect of the present invention, a housing having a housing portion therein, a rotor disposed in the housing portion and driven to rotate from the outside of the housing, the rotor housed therein, and the interior of the housing portion A plurality of working chambers are formed between a cam ring in which the amount of eccentricity between the rotation center of the rotor and the center of the rotor changes linearly and an inner periphery of the cam ring. A biasing member that applies a biasing force to the cam ring in a direction in which the eccentric amount of the rotor and the cam ring increases, and a biasing member that is integrally provided on the outer periphery of the cam ring and that biases the biasing member against the cam ring. A piston portion provided at a position opposite to the direction and the piston portion slidably formed on the inner periphery of the housing, and lubricates the sliding portion of the internal combustion engine A control oil chamber into which oil is introduced from a main oil gallery that supplies the suction oil, and a suction side region that is formed on one side of the inner peripheral side of the housing and that increases the volume of each working chamber when the rotor is rotationally driven. And a discharge part formed on the discharge side region in which the volume of each hydraulic oil chamber is reduced when the rotor is rotationally driven. And a seal member provided at a position on the discharge portion side, which is a sliding surface between the piston portion and the inner wall surface of the control oil chamber.

More preferably, the piston portion has a quadrangular cross section in a direction perpendicular to the moving direction axis of the cam ring.

More preferably, the seal member is provided on at least one side of the piston portion on the side of the discharge portion.

More preferably, the seal member is disposed in a seal groove provided on at least one side of the piston portion.

More preferably, the seal member includes a seal body that slides on the inner wall surface of the control oil chamber, and an elastic body that biases the seal body toward the inner wall surface of the control oil chamber.

More preferably, the seal body is made of a material that is harder and has a lower sliding resistance than the elastic body.

More preferably, the seal member is provided on one side of the discharge unit side and at least one side surface connected to the one side.

More preferably, the seal member is disposed in a seal groove provided in the piston portion.

More preferably, a second piston portion provided integrally with the cam ring and provided at a position facing the piston portion in the moving direction of the cam ring is provided.

More preferably, the second piston portion is slidably disposed in a recess formed in the housing, and is a sliding portion between the recess and the second piston portion, and at least the discharge portion. A second seal member is provided at the side position.

More preferably, the second piston portion urges the cam ring toward the control oil chamber by the urging member.

More preferably, the second piston portion has a state in which a pressure lower than the discharge pressure introduced into the concave portion is applied.

More preferably, the second piston portion has a quadrangular cross section in a direction perpendicular to the moving direction axis of the cam ring.

More preferably, the second seal member is provided on one side of the square surface of the second piston portion and on one side continuous to the one side.

More preferably, the second seal member is disposed in a second seal groove formed on at least one side of the second piston portion.

More preferably, the second seal member is biased toward the sliding surface by the second elastic body.

More preferably, the second seal member is provided on one side surface connected to the one side in addition to the one side on the discharge portion side of the second piston portion.

As another preferred aspect, a housing having a housing portion inside,
A pump structure that is disposed in the housing and discharges the sucked oil to the outside of the housing; a variable member that variably controls the flow rate of oil discharged from the pump structure by movement; and the pump structure A biasing member that biases the variable member in a direction in which the flow rate of oil discharged from the body increases; and a biasing direction of the biasing member that is provided integrally with the variable member and in the moving direction of the variable member. The oil is guided from a main oil gallery which is composed of a piston portion provided at a position opposite to the shaft, the housing and the piston portion, and supplies oil for lubricating the sliding portion of the internal combustion engine. An oil chamber is provided at a position adjacent to the control oil chamber, and the oil discharged from the pump component is guided, so that the housing in the piston portion is guided. A discharge part that applies a pressing force in one direction to the sliding part with the seal, and a seal member that is provided in the sliding part of the housing and the piston part and suppresses oil leakage from the discharge part to the control oil chamber And.

More preferably, the control oil chamber is formed in a concave shape on the inner surface of the housing, and the piston portion is slidably disposed in the control oil chamber and has a cross section perpendicular to the moving direction of the variable member. The shape is formed in a quadrangular shape, and the seal member is disposed between the inner wall surface of the control oil chamber and the outer surface of the piston portion.

Claims

A housing having an accommodating portion therein;
A rotor disposed in the housing and driven to rotate from the outside of the housing;
A cam ring in which the rotor is housed and the amount of eccentricity between the center of rotation of the rotor and the center of the rotor changes by moving linearly in the housing portion;
A vane provided on the outer periphery of the rotor and forming a plurality of working chambers with the inner periphery of the cam ring;
An urging member for applying an urging force to the cam ring in a direction in which the eccentric amount of the rotor and the cam ring is increased;
A piston portion provided integrally with the outer periphery of the cam ring and provided at a position opposite to the biasing direction of the biasing member with respect to the cam ring;
A control oil chamber in which the piston portion is slidably formed on the inner periphery of the housing, and oil is introduced from a main oil gallery that supplies lubricating oil to the sliding portion of the internal combustion engine;
A suction portion formed on one side of the inner peripheral side of the housing and formed in an opening side region in which the volume of each working chamber increases when the rotor is driven to rotate;
A discharge part formed on the other side of the inner peripheral side of the housing and having an opening formed in a discharge side region in which the volume of each hydraulic oil chamber decreases as the rotor rotates.
A sliding surface between the piston portion and the inner wall surface of the control oil chamber, and a seal member provided at a position on the discharge portion side;
A variable displacement oil pump characterized by comprising:
The variable displacement oil pump according to claim 1,
The piston section has a quadrangular cross section in a direction orthogonal to the moving direction axis of the cam ring.
The variable displacement oil pump according to claim 2,
The variable displacement oil pump according to claim 1, wherein the seal member is provided on at least one side of the piston portion on the side of the discharge portion.
The variable displacement oil pump according to claim 3,
The variable displacement oil pump according to claim 1, wherein the seal member is disposed in a seal groove provided on at least one side of the piston portion.
The variable displacement oil pump according to claim 4, wherein
The seal member is composed of a seal body that slides on the inner wall surface of the control oil chamber, and an elastic body that biases the seal body toward the inner wall surface of the control oil chamber. Shape oil pump.
The variable displacement oil pump according to claim 5,
The variable capacity oil pump, wherein the seal body is formed of a material that is harder than the elastic body and has a small sliding resistance.
The variable displacement oil pump according to claim 3,
The variable displacement oil pump according to claim 1, wherein the seal member is provided on one side of the discharge portion side and at least one side surface continuous with the one side.
The variable displacement oil pump according to claim 7,
The variable displacement oil pump, wherein the seal member is disposed in a seal groove provided in the piston portion.
The variable displacement oil pump according to claim 1,
A variable displacement oil pump provided with a second piston portion provided integrally with the cam ring and provided at a position facing the piston portion in a moving direction of the cam ring.
The variable displacement oil pump according to claim 9,
The second piston part is slidably disposed in a recess formed in the housing, and is a sliding part between the recess and the second piston part, at least at a position on the discharge part side. A variable displacement oil pump, wherein a second seal member is provided.
The variable displacement oil pump according to claim 9,
The variable displacement oil pump, wherein the second piston portion urges the cam ring toward the control oil chamber by the urging member.
The variable displacement oil pump according to claim 9,
The variable piston type oil pump according to claim 1, wherein the second piston portion has a state in which a pressure lower than the discharge pressure introduced into the recess is present.
The variable displacement oil pump according to claim 9,
The variable displacement oil pump according to claim 2, wherein the second piston portion has a quadrangular cross section in a direction orthogonal to the moving direction axis of the cam ring.
The variable displacement oil pump according to claim 13,
The variable-capacity oil pump, wherein the second seal member is provided on one side of the square side surface of the second piston portion on the discharge portion side and on one side surface connected to the one side.
The variable displacement oil pump according to claim 14,
The variable capacity type oil pump, wherein the second seal member is disposed in a second seal groove formed on at least one side of the second piston portion.
The variable displacement oil pump according to claim 10,
The variable displacement oil pump, wherein the second seal member is biased toward the sliding surface by a second elastic body.
The variable displacement oil pump according to claim 14,
The variable capacity oil pump, wherein the second seal member is provided on one side surface connected to the one side in addition to the one side on the discharge portion side of the second piston portion.
A housing having an accommodating portion therein;
A pump structure that is disposed in the housing and discharges the sucked oil to the outside of the housing;
A variable member that variably controls the flow rate of oil discharged from the pump component by moving;
An urging member that urges the variable member in a direction in which the flow rate of oil discharged from the pump structure increases.
A piston portion provided integrally with the variable member, and provided in a position opposite to the biasing direction of the biasing member in the moving direction of the variable member;
A control oil chamber that is constituted by the housing and the piston portion, and in which the oil is guided from a main oil gallery that supplies oil for lubricating the sliding portion of the internal combustion engine;
A discharge part that is provided at a position adjacent to the control oil chamber, and that guides the oil discharged from the pump structure to apply a unidirectional pressing force to the sliding part of the piston part with the housing;
A seal member provided in a sliding portion of the housing and the piston portion, and suppressing leakage of oil from the discharge portion to a control oil chamber;
A variable displacement oil pump characterized by comprising:
The variable displacement oil pump according to claim 18,
The control oil chamber is formed in a concave shape on the inner surface of the housing,
The piston portion is slidably disposed in the control oil chamber, and a cross-sectional shape perpendicular to the moving direction of the variable member is formed in a quadrangular shape.
The variable displacement oil pump according to claim 1, wherein the seal member is disposed between an inner wall surface of the control oil chamber and an outer surface of the piston portion.