JP2024002459A - vane pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve operating efficiency of a vane pump.

SOLUTION: A vane pump 100 comprises a cam ring 4, and a body side plate 30 as a side member provided in contact with one side surface of the cam ring 4. The body side plate 30 comprises a first back pressure groove 34 as a back pressure groove communicating with a back pressure chamber 5 in suction regions 42a and 42c in which the capacity of a pump chamber 6 is expanded. The first back pressure groove 34 comprises a high-pressure groove 34a as a first groove for guiding working fluid to the back pressure chamber 5, and a low-pressure groove 34b as a second groove for guiding the working fluid to the back pressure chamber 5 closer to the forward side in the rotation direction of a rotor 2 than the back pressure chamber 5 to which the high-pressure groove 34a guides the working fluid, and guiding the working fluid having a lower pressure than that of the working fluid to be guided by the high-pressure groove 34a, to the back pressure chamber 5. The working fluid is selectively guided to the back pressure chamber 5 from the high-pressure groove 34a or the low-pressure groove 34b in association with rotation of the rotor 2.

SELECTED DRAWING: Figure 5

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a vane pump.

Patent Document 1 describes a rotor that is rotationally driven, a plurality of slits that open on the outer peripheral surface of the rotor, a plurality of vanes that are slidably housed in the slits, and a plurality of vanes that are rotated as the rotor rotates. A cam ring having an inner circumferential cam surface with which a tip portion slides, a pair of side members arranged to sandwich the rotor and the cam ring, and a pump chamber defined by the rotor, the cam ring, adjacent vanes, and the pair of side members. A vane pump is disclosed. A back pressure chamber is defined by the inner peripheral surface of the slit and the base end of the vane, and high pressure working fluid is introduced into the back pressure chamber from a discharge port provided on one side member. The vane is pushed in the direction of protruding from the slit by the fluid pressure in the back pressure chamber that presses the base end and the centrifugal force that acts as the rotor rotates, and the tip of the vane touches the inner cam surface of the cam ring. Sliding contact. As a result, the vanes protrude from the slits as the rotor rotates, and the volume of the pump chamber expands.

JP2020-41484A

In the vane pump described in Patent Document 1, when the pressure of the working fluid introduced into the back pressure chamber is high, the vane is strongly pressed toward the inner cam surface, so there is a gap between the vane and the inner cam surface. The resulting frictional force increases. This causes a loss in the rotational torque of the rotor, which may reduce the operating efficiency of the vane pump.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the operating efficiency of a vane pump.

The present invention includes a rotor that is rotationally driven, a plurality of slits that open on the outer peripheral surface of the rotor, a plurality of vanes that are slidably housed in the slits, and tips of the vanes that slide as the rotor rotates. a cam ring having inner circumferential cam surfaces in contact with each other; a side member provided in contact with one side of the cam ring; a pump chamber defined by the rotor, the cam ring, and a pair of adjacent vanes; and a proximal end of the vane within the slit. a back pressure chamber defined by a side member, the side member has a back pressure groove that communicates with the back pressure chamber in a suction region where the volume of the pump chamber expands, and the back pressure groove allows working fluid to flow into the back pressure chamber. a first groove that guides the working fluid, and a working fluid that is lower in pressure than the working fluid that the first groove guides, and a working fluid that is lower in pressure than the working fluid that the first groove guides. and a second groove that guides the fluid to the back pressure chamber, and the working fluid is selectively guided to the back pressure chamber from the first groove or the second groove as the rotor rotates.

In this invention, the back pressure groove communicates with the back pressure chamber in the suction region, the first groove guides high pressure working fluid to the back pressure chamber on the rear side in the rotation direction of the rotor, and the second groove leads the high pressure working fluid to the back pressure chamber on the front side in the rotation direction of the rotor. A low-pressure working fluid is introduced into the back pressure chamber. Therefore, in the suction region, the pressure of the working fluid led to the back pressure chamber is high in the area where the change in the amount of vane protrusion is large (the rear side in the rotational direction of the rotor), and the pressure of the working fluid led to the back pressure chamber is high in the area where the change in the amount of protrusion of the vane is small (the rear side in the rotational direction of the rotor). On the front side), the pressure of the working fluid guided to the back pressure chamber is low. As a result, in a region where the change in the amount of protrusion of the vane is small, the force that presses the vane toward the inner cam surface becomes smaller, and the frictional force generated between the vane and the inner cam surface becomes smaller. In addition, in areas where the change in the amount of vane protrusion is small, the vane can be protruded with a small force and brought into sliding contact with the inner cam surface, so even if the pressure of the working fluid in the back pressure chamber is small, it will affect the operation of the vane pump. will not be given. This reduces the loss of rotational torque of the rotor and improves the operating efficiency of the vane pump.

Further, the present invention is characterized in that the second groove is provided separately from the first groove so as not to communicate with the first groove.

In this invention, by dividing the back pressure groove into the first groove and the second groove, it is possible to reduce the frictional force generated between the vane and the inner circumferential cam surface in a region where the change in the protrusion amount of the vane is small. can.

Furthermore, the present invention is characterized in that the side member further includes a suction port that guides the working fluid into the pump chamber, and a communication groove that communicates the second groove with the suction port.

In this invention, the second groove and the suction port communicate with each other through the communication groove, so that the low-pressure working fluid can be guided to the second groove.

Further, the present invention is characterized in that the communication groove is provided offset from the direction in which the slit extends.

Further, the present invention is characterized in that the slits are provided to extend radially along the radial direction of the rotor, and the communication grooves are provided to extend linearly with deviation from the radial direction of the rotor.

In these inventions, it is possible to prevent the communication groove from interfering with sliding of the vane within the slit.

Further, in the present invention, the inner circumferential cam surface has a first curved surface that is provided in the suction region and whose radial dimension with respect to the rotor increases by a constant amount of change along the rotational direction of the rotor; a second curved surface that is continuous and provided in the suction region on the forward side in the rotational direction of the rotor than the first curved surface, and the amount of change in the radial dimension between the second curved surface and the rotor is smaller along the rotational direction of the rotor; However, as the rotor rotates, the second groove starts communicating with the back pressure chamber at a position corresponding to the boundary between the first curved surface and the second curved surface.

In this invention, the amount of change in the radial dimension of the second curved surface relative to the rotor along the rotational direction of the rotor is reduced. Therefore, when the vane slides on the second curved surface, the change in the amount of protrusion of the vane due to rotation of the rotor is small. Therefore, the second groove communicates with the back pressure chamber from the region where the change in the amount of protrusion of the vane begins to decrease as the rotor rotates, and guides the low-pressure working fluid to the back pressure chamber. Therefore, the second groove can efficiently reduce the frictional force generated between the vane and the inner circumferential cam surface in a region where the change in the amount of protrusion of the vane is small.

According to the present invention, the operating efficiency of the vane pump can be improved.

FIG. 1 is a sectional view of a vane pump according to an embodiment of the present invention. It is a front view of a rotor, a vane, and a cam ring, and shows a state where a rotor, a vane, and a cam ring were assembled. FIG. 3 is an enlarged view of the transition portion of the inner cam surface of FIG. 2; It is a graph which shows the relationship between the amount of protrusion of the vane in the suction region, and the amount of rotation of the rotor. FIG. 3 is a front view of the body-side side plate. FIG. 3 is a front view of the cover-side side plate.

Hereinafter, a vane pump according to an embodiment of the present invention will be described with reference to the drawings. A vane pump is used as a fluid pressure supply source for fluid pressure equipment (for example, a power steering device, a transmission, etc.) mounted on a vehicle. Although a vane pump using hydraulic oil as the working fluid will be described here, other fluids such as working water may be used as the working fluid.

As shown in FIGS. 1 and 2, the vane pump 100 includes a pump body 10 in which a pump housing recess 10A is formed, a pump cover 20 that covers the opening of the pump housing recess 10A and is fixed to the pump body 10, and a pump cover 20 that covers the opening of the pump housing recess 10A and is fixed to the pump body 10. A drive shaft 1 rotatably supported by a body 10 and a pump cover 20 via bearings 11 and 12, a rotor 2 connected to the drive shaft 1 and rotationally driven, and a plurality of rotors opening on the outer peripheral surface of the rotor 2. It includes a slit 2s, a plurality of vanes 3 slidably housed in the slit 2s, and a cam ring 4 having an inner circumferential cam surface 4a with which the tip portion 3a of the vane 3 slides as the rotor 2 rotates. . Cam ring 4 accommodates rotor 2 and vane 3.

The vane pump 100 is driven by a drive device (not shown) such as an engine, and a rotor 2 connected to a drive shaft 1 is driven to rotate counterclockwise as shown by an arrow in FIG. to occur.

In the following, the direction along the rotation axis of the rotor 2 will be referred to as the "axial direction", and the radial direction centered on the rotation axis of the rotor 2 will be referred to as the "radial direction", and the direction in which the rotor 2 rotates when the vane pump 100 is operated is referred to as the "radial direction". It is called "rotation direction."

As shown in FIG. 1, the vane pump 100 includes a body-side side plate 30 as a side member that is provided at one axial end of the rotor 2 and in contact with one side of the rotor 2 and the cam ring 4; It further includes a cover-side side plate 40 that is provided on the other end in the axial direction and comes into contact with the other side surface of the rotor 2 and the cam ring 4.

The body-side side plate 30 is provided between the bottom surface of the pump housing recess 10A and the rotor 2. One axial end surface of the rotor 2 is in sliding contact with the body-side side plate 30, and one axial end surface of the cam ring 4 is in contact with the body side side plate 30. The cover-side side plate 40 is provided between the rotor 2 and the pump cover 20. The other axial end surface of the rotor 2 is in sliding contact with the cover-side side plate 40, and the other axial end surface of the cam ring 4 is in contact with the cover side plate 40.

In this way, the body-side side plate 30 and the cover-side side plate 40 are arranged to face both side surfaces of the rotor 2 and the cam ring 4. That is, the body-side side plate 30 and the cover-side side plate 40 are arranged to sandwich the rotor 2 and the cam ring 4 in the axial direction.

The body-side side plate 30, the rotor 2, the cam ring 4, and the cover-side side plate 40 are accommodated in the pump housing recess 10A of the pump body 10. In this state, the pump cover 20 is attached to the pump body 10, thereby sealing the pump housing recess 10A.

As shown in FIG. 2, a plurality of slits 2s are formed in the rotor 2 so as to extend radially along the radial direction of the rotor 2. As shown in FIG. The opening of the slit 2s is formed in a protrusion 23 that protrudes radially outward from the outer periphery of the rotor 2.

The vane 3 is formed into a rectangular flat plate shape. The vane 3 is slidably inserted into the slit 2s and has a distal end 3a that is an end protruding from the slit 2s, and a proximal end 3b that is an end opposite to the distal end 3a. . A back pressure chamber 5 is defined by the base end portion 3b of the vane 3 within the slit 2s. The back pressure chamber 5 communicates with the high pressure chamber 14 or the low pressure chamber 21, as described later, and hydraulic oil is introduced into the back pressure chamber 5 from the high pressure chamber 14 or the low pressure chamber 21. The vane 3 is pushed in the direction of protruding from the slit 2s by the pressure of the hydraulic oil guided to the back pressure chamber 5.

The cam ring 4 is an annular member having an inner circumferential cam surface 4a that is a substantially oval inner circumferential surface, and a pin hole 4b through which the positioning pin 8 is inserted. The inner circumferential cam surface 4a is a surface on which the tip portions 3a of the plurality of vanes 3 come into sliding contact as the rotor 2 rotates.

When the rotor 2 rotates, centrifugal force is generated in the vanes 3. This centrifugal force pushes the vane 3 in the direction of protruding from the slit 2s. In other words, the vane 3 is pressed in the direction of protruding from the slit 2s (radially outward) by the fluid pressure in the back pressure chamber 5 pressing the base end 3b and the centrifugal force acting as the rotor 2 rotates. Ru. When the vane 3 is pressed outward in the radial direction, the tip end 3a of the vane 3 comes into sliding contact with the inner cam surface 4a of the cam ring 4. As a result, a pump chamber 6 is defined inside the cam ring 4 by the outer circumferential surface of the rotor 2, the inner circumferential cam surface 4a of the cam ring 4, and a pair of adjacent vanes 3.

The inner circumferential cam surface 4a is formed in a substantially elliptical shape. Therefore, as the rotor 2 rotates, the volume of the pump chamber 6 repeatedly expands and contracts. Hydraulic oil is sucked into an expansion area (suction area) where the pump chamber 6 expands, and hydraulic oil is discharged from a contraction area (discharge area) where the pump chamber 6 contracts.

As shown in FIG. 2, the vane pump 100 according to the present embodiment has a first suction region 42a and a first discharge region 42b where the vane 3 makes the first reciprocating motion, and a first discharge region 42b where the vane 3 makes the second reciprocating motion. It has a second suction region 42c and a second discharge region 42d. During one rotation of the rotor 2, the pump chamber 6 expands in the first suction region 42a, contracts in the first discharge region 42b, expands in the second suction region 42c, and expands in the second suction region 42c. It contracts in the discharge area 42d. The vane pump 100 has two suction regions 42a, 42c and two discharge regions 42b, 42d, but is not limited to this, and has a configuration having one or more suction regions and one or more discharge regions. You can also use it as

The inner circumferential cam surface 4a includes a first curved surface 141, which is provided in each of the suction regions 42a and 42c, and whose radial dimension with respect to the rotor 2 increases by a constant amount of change along the rotational direction of the rotor 2; It is continuous with one curved surface 141 and is provided in each of the suction regions 42a, 42c on the forward side in the rotational direction of the rotor 2 than the first curved surface 141, and the radial dimension between it and the rotor 2 along the rotational direction of the rotor 2. a second curved surface 142 whose amount of change is smaller than that of the first curved surface 141. The boundary between the first curved surface 141 and the second curved surface 142 is defined as a boundary 143.

Specifically, the radial dimension between the first curved surface 141 and the rotor 2 is the radial dimension between the first curved surface 141 and the portion of the rotor 2 where the slit 2s opens. For example, taking the first curved surface 141 as an example, the radial dimension between the first curved surface 141 and the rotor 2 is as shown in FIG. The radial dimension is A. In addition, in FIG. 3, for convenience of explanation, description of the structure provided on the body side side plate 30 is omitted. In other words, the radial dimension between the first curved surface 141 and the rotor 2 corresponds to the amount of protrusion of the vane 3 from the slit 2s of the rotor 2. Further, the amount of change in the radial dimension between the first curved surface 141 and the rotor 2 corresponds to the change in the amount of protrusion of the vane 3. The same applies to the second curved surface 142.

The vane 3 protrudes from the slit 2s from the first curved surface 141 to the second curved surface 142 until it reaches the maximum protrusion amount. The first curved surface 141 is provided so that the radial dimension between the rotor 2 and the rotor 2 increases by a certain amount of change along the rotational direction of the rotor 2. In the state of sliding contact with the vane 3, as shown in FIG. 4, the vane 3 protrudes from the slit 2s at a constant speed. Further, since the second curved surface 142 is provided so that the amount of change in the radial dimension between the rotor 2 and the rotor 2 is small along the rotational direction of the rotor 2, the vane 3 passes through the boundary 143 and the second curved surface 142 In the state of sliding contact, the speed at which the vane 3 protrudes from the slit 2s gradually decreases. When the amount of protrusion of the vane 3 becomes maximum, the speed at which the vane 3 protrudes from the slit 2s becomes zero. Thus, in the suction regions 42a and 42c, the change in the amount of protrusion of the vane 3 is large on the rear side in the rotational direction of the rotor 2, and the change in the protrusion amount of the vane 3 is small on the front side in the rotational direction of the rotor 2.

As shown in FIG. 1, an annular high pressure chamber 14 is defined by the pump body 10 and the body-side side plate 30 on the bottom side of the pump housing recess 10A of the pump body 10. The high pressure chamber 14 is connected to a fluid pressure device 70 (for example, a power steering device, a transmission, etc.) outside the vane pump 100 via a discharge passage 62. The discharge passage 62 is, for example, a passage provided on the vane pump 100 side.

A low pressure chamber 21 is formed in the pump cover 20, and a detour passage 13 communicating with the low pressure chamber 21 is formed in the inner peripheral surface of the pump housing recess 10A. Two detour passages 13 are provided at opposing positions with the cam ring 4 in between. Low pressure chamber 21 is connected to tank 60 via suction passage 61.

As shown in FIGS. 1 and 2, the cam ring 4 is provided with notches 4c and 4d that penetrate from the outer circumferential surface to the inner circumferential cam surface 4a. The notch portion 4c opens on the side surface in contact with the body-side side plate 30, and the notch portion 4d opens on the side surface in contact with the cover-side side plate 40.

FIG. 5 is a front view of the body-side side plate 30 seen from the cam ring 4 side. As shown in FIG. 5, the body-side side plate 30 includes a sliding surface 30a on which the side surface of the vane 3 slides, a discharge port 31 formed to correspond to each of the discharge regions 42b and 42d, and a drive shaft. 1, a suction port 33 formed to correspond to each of the suction regions 42a and 42c, and a pin hole 39 through which the positioning pin 8 is inserted.

The discharge ports 31 are provided at two positions facing each other with the through hole 32 in between. The discharge port 31 is formed in an arc shape centered on the through hole 32 . The discharge port 31 penetrates the body-side side plate 30 and communicates with the high pressure chamber 14 formed in the pump body 10. The discharge port 31 guides hydraulic oil discharged from the pump chamber 6 to the high pressure chamber 14 . The hydraulic oil that has flowed into the high pressure chamber 14 is supplied to the fluid pressure device 70 outside the vane pump 100 through the discharge passage 62 (see FIG. 1).

The suction ports 33 are provided at two positions facing each other with the through hole 32 in between. The suction port 33 is formed at a position corresponding to the detour passage 13 of the pump housing recess 10A. The suction port 33 is formed to have a concave shape that opens outward in the radial direction. The outer peripheral end of the suction port 33 reaches the outer peripheral surface of the body-side side plate 30.

As shown in FIG. 1, when the body-side side plate 30 is assembled to the cam ring 4, the suction port 33 of the body-side side plate 30 faces the notch 4c of the cam ring 4. The hydraulic oil in the detour passage 13 is guided to the pump chamber 6 through between the notch 4c and the suction port 33. The suction port 33 guides hydraulic oil from the low pressure chamber 21 to the pump chamber 6.

As shown in FIG. 5, a groove-shaped notch 36 is formed in the sliding surface 30a of the body-side side plate 30. The notch 36 is provided at the end of the discharge port 31 on the communication start side where the pump chamber 6 begins to communicate as the rotor 2 rotates, and communicates with the discharge port 31 . The notch 36 is formed so that its opening area gradually increases in the direction of rotation of the rotor 2. By forming the notch 36, hydraulic oil is supplied to the pump chamber 6 through the notch 36 before the pump chamber 6 opens directly to the discharge port 31. This increases the pressure in the pump chamber 6, thereby preventing rapid pressure fluctuations in the high pressure chamber 14.

The body-side side plate 30 has a first back pressure groove 34 as a pair of back pressure grooves provided in the suction areas 42a and 42c, respectively, a second back pressure groove 35 provided in the discharge areas 42b and 42d, and a first groove. It has a communication groove 37 that communicates a low pressure groove 34b of the back pressure groove 34, which will be described later, and the suction port 33. The back pressure grooves 34 and 35 are provided in an arc shape centered on the through hole 32, and open to the sliding surface 30a. The pair of first back pressure grooves 34 are provided to face each other with the through hole 32 in between. The pair of second back pressure grooves 35 are provided to face each other with the through hole 32 in between. The pair of second back pressure grooves 35 are provided at positions shifted by approximately 90° from the pair of first back pressure grooves 34 with respect to the through hole 32 . The back pressure grooves 34 and 35 overlap and communicate with the plurality of back pressure chambers 5 as the rotor 2 rotates. The first back pressure groove 34 communicates with the back pressure chamber 5 in the suction regions 42a, 42c, and the second back pressure groove 35 communicates with the back pressure chamber 5 in the discharge regions 42b, 42d.

The first back pressure groove 34 includes a high pressure groove 34a serving as a first groove that guides hydraulic oil to the back pressure chamber 5, and a high pressure groove 34a that is provided on the front side in the rotational direction of the rotor 2 than the high pressure groove 34a, and is provided with a high pressure groove 34a as a first groove that guides hydraulic oil to the back pressure chamber 5. It has a low pressure groove 34b as a second groove that guides hydraulic oil at a lower pressure than the lower pressure to the back pressure chamber 5. The low pressure groove 34b is provided separately from the high pressure groove 34a so as not to communicate with the high pressure groove 34a. In this embodiment, the first back pressure groove 34 includes two grooves: a high pressure groove 34a and a low pressure groove 34b.

The high pressure groove 34a is provided in an arc shape. As shown in FIG. 1, the high pressure groove 34a is provided to penetrate the body side plate 30 and communicates with the high pressure chamber 14. Thereby, high pressure hydraulic oil from the discharge port 31 is guided to the back pressure chamber 5 through the high pressure chamber 14 and the high pressure groove 34a. The high pressure groove 34a is provided in a region corresponding to the first curved surface 141 of the inner cam surface 4a of the cam ring 4. Specifically, the high pressure groove 34a is provided such that the first curved surface 141 is located on a straight line passing through the high pressure groove 34a from the rotation center axis O of the rotor 2 in a front view as shown in FIG. That is, the back pressure chamber 5 presses the vane 3 toward the first curved surface 141 using the hydraulic oil guided through the high pressure groove 34a, and causes the vane 3 to come into sliding contact with the first curved surface 141.

The low pressure groove 34b is provided in an arc shape. The low pressure groove 34b does not penetrate the body side side plate 30 and does not communicate with the high pressure chamber 14. The low pressure groove 34b communicates with the suction port 33 through the communication groove 37. Thereby, the low pressure hydraulic oil from the suction port 33 is guided to the back pressure chamber 5 through the communication groove 37 and the low pressure groove 34b. The low pressure groove 34b is provided in a region corresponding to the second curved surface 142 of the inner cam surface 4a of the cam ring 4, and as the rotor 2 rotates, the low pressure groove 34b is provided at a position corresponding to the boundary 143 between the first curved surface 141 and the second curved surface 142. It starts communicating with the back pressure chamber 5. Specifically, in the front view of the low pressure groove 34b as shown in FIG. The boundary 143 is provided so as to be located on a straight line passing through the rear end of the low pressure groove 34b in the rotational direction. In other words, the hydraulic oil guided to the back pressure chamber 5 through the low pressure groove 34b presses the vane 3 toward the second curved surface 142, causing the vane 3 to come into sliding contact with the second curved surface 142. In this way, the low pressure groove 34b guides the working fluid to the back pressure chamber 5 on the forward side in the rotational direction of the rotor 2 rather than the back pressure chamber 5 to which the high pressure groove 34a leads the working oil. In the vane pump 100 of this embodiment, hydraulic oil is selectively introduced into the back pressure chamber 5 from the high pressure groove 34a or the low pressure groove 34b as the rotor 2 rotates.

The communication groove 37 is provided to extend linearly between the low pressure groove 34b and the suction port 33, and is open to the sliding surface 30a of the body-side side plate 30. The communication groove 37 does not penetrate the body-side side plate 30 and does not communicate with the high pressure chamber 14. Therefore, only low-pressure hydraulic oil from the suction port 33 is guided to the low-pressure groove 34b through the communication groove 37. The communication groove 37 is provided offset from the direction in which the slit 2s extends. Specifically, the communication groove 37 is provided to be offset from the radial direction of the rotor 2 . In this embodiment, the communication groove 37 is provided to extend from the end of the low-pressure groove 34b on the rear side in the rotational direction of the rotor 2 to the suction port 33. Therefore, the communication groove 37 does not inhibit sliding of the vane 3 within the slit 2s. Note that the communication groove 37 may be provided along the direction in which the slit 2s extends, although this will hinder the sliding movement of the vane 3.

The second back pressure groove 35 is provided to penetrate the body side side plate 30 and communicates with the high pressure chamber 14 . Thereby, high-pressure hydraulic oil from the discharge port 31 is guided to the back pressure chamber 5 through the high pressure chamber 14 and the second back pressure groove 35. The hydraulic oil guided to the back pressure chamber 5 through the second back pressure groove 35 presses the vane 3 toward the inner cam surface 4a in the discharge areas 42b and 42d, causing the vane 3 to slide into contact with the inner cam surface 4a. .

FIG. 6 is a front view of the cover side plate 40 seen from the pump cover 20 side. As shown in FIG. 6, the cover side plate 40 has a sliding surface 40a (see FIG. 1) on which the side surface of the vane 3 slides, a through hole 42 through which the drive shaft 1 is inserted, and suction regions 42a and 42c. It is a plate-like member having notches 43 formed to correspond to each other and a pin hole 49 through which the positioning pin 8 is inserted. The cover-side side plate 40 is positioned with respect to the cam ring 4 and the body-side side plate 30 by the positioning pin 8.

Two notches 43 are provided at opposing positions with the through hole 42 in between. The notch portion 43 is formed at a position corresponding to the detour passage 13 of the pump housing recess 10A. The cutout portion 43 is provided to open outward in the radial direction. As shown in FIG. 1, when the cover side plate 40 is assembled to the cam ring 4, the notch 43 of the cover side plate 40 faces the notch 4d of the cam ring 4. The hydraulic oil in the detour passage 13 and the low pressure chamber 21 is guided to the pump chamber 6 through the notch 43 and the notch 4d.

In this way, the pair of suction ports 33 are located in the suction regions 42a, 42c, and the pair of discharge ports 31 are located in the discharge regions 42b, 42d. Furthermore, hydraulic oil is introduced into the pump chamber 6 from both sides in the axial direction through the suction port 33 and the notch 43 of the cover-side side plate 40.

Next, the operation of vane pump 100 will be explained.

When the drive shaft 1 is rotationally driven by the power of a drive device (not shown) such as an engine, the rotor 2 rotates in the direction shown by the arrow in FIG. As the rotor 2 rotates, the pump chamber 6 located in the suction areas 42a and 42c expands. As a result, the hydraulic oil in the tank 60 is sucked into the pump chamber 6 through the suction passage 61, the low pressure chamber 21, the suction port 33, and the notch 43 of the cover side plate 40, as shown in FIG. Further, as the rotor 2 rotates, the pump chambers 6 located in the discharge areas 42b and 42d contract. As a result, the hydraulic oil in the pump chamber 6 is discharged into the high pressure chamber 14 through the discharge port 31 (see FIG. 2). The hydraulic fluid discharged into the high pressure chamber 14 is supplied to an external fluid pressure device 70 through a discharge passage 62. In the vane pump 100 of this embodiment, each pump chamber 6 repeats suction and discharge of hydraulic oil twice while the rotor 2 rotates once.

A portion of the hydraulic fluid discharged into the high pressure chamber 14 is supplied to the back pressure chamber 5 through the back pressure grooves 34 and 35, and presses the base end 3b of the vane 3 toward the inner circumferential cam surface 4a. Therefore, the vane 3 is pressed in the direction of protruding from the slit 2s by the fluid pressure in the back pressure chamber 5 pressing the base end 3b and the centrifugal force acting as the rotor 2 rotates. As a result, the tip portion 3a of the vane 3 rotates while slidingly contacting the inner circumferential cam surface 4a of the cam ring 4, so that the hydraulic oil in the pump chamber 6 is transferred between the tip portion 3a of the vane 3 and the inner circumferential cam surface 4a of the cam ring 4. It is discharged from the discharge port 31 without leaking between the two.

Here, when the pressure of the hydraulic oil introduced into the back pressure chamber is high, the vane is strongly pressed toward the inner circumferential cam surface, so that the frictional force generated between the vane and the inner circumferential cam surface becomes large. This causes a loss in the rotational torque of the rotor, which may reduce the operating efficiency of the vane pump. However, if the pressure of the hydraulic oil led to the back pressure chamber is low, the vane cannot protrude toward the inner cam surface in the suction area and come into contact with the inner cam surface, and the hydraulic oil in the pump chamber It leaks from between the tip and the inner cam surface of the cam ring.

On the other hand, in the vane pump 100 of the present embodiment, as described above, the first back pressure groove 34 having the high pressure groove 34a and the low pressure groove 34b is provided in the suction regions 42a and 42c. The first back pressure groove 34 communicates with the back pressure chamber 5 in the suction regions 42a and 42c. The high pressure groove 34a guides high pressure hydraulic oil from the high pressure chamber 14 to the back pressure chamber 5 on the rear side in the rotation direction of the rotor 2, and the low pressure groove 34b guides the high pressure hydraulic oil from the high pressure chamber 14 into the back pressure chamber 5 on the front side in the rotation direction of the rotor 2. 21 leads to low pressure hydraulic oil. Further, in the suction regions 42a and 42c, the change in the protrusion amount of the vane 3 is large on the front side in the rotation direction of the rotor 2, and the change in the protrusion amount of the vane 3 is small on the rear side in the rotation direction of the rotor 2. Therefore, in the suction regions 42a and 42c, in the region where the change in the protrusion amount of the vane 3 is large (the rear side in the rotational direction of the rotor 2), the pressure of the hydraulic oil guided to the back pressure chamber 5 is high, and the change in the protrusion amount of the vane 3 is high. In a region where the pressure is small (on the front side in the rotational direction of the rotor 2), the pressure of the hydraulic fluid guided to the back pressure chamber 5 is low. As a result, in a region where the change in the amount of protrusion of the vane 3 is small, the force that presses the vane 3 toward the inner cam surface 4a becomes smaller, and the frictional force generated between the vane 3 and the inner cam surface 4a becomes smaller. Become. Further, in a region where the change in the amount of protrusion of the vane 3 is small, the vane 3 can be protruded with a small force and brought into sliding contact with the inner circumferential cam surface 4a. Therefore, even if the pressure of the hydraulic oil in the back pressure chamber 5 in this area is small, the operation of the vane pump 100 is not affected. This reduces the loss of rotational torque of the rotor 2 and improves the operating efficiency of the vane pump 100.

Furthermore, in the vane pump 100, as the rotor 2 rotates, the low pressure groove 34b begins to communicate with the back pressure chamber 5 at a position corresponding to the boundary 143 between the first curved surface 141 and the second curved surface 142. Therefore, the low pressure groove 34b communicates with the back pressure chamber 5 from the region where the change in the amount of protrusion of the vane 3 begins to decrease as the rotor 2 rotates, and guides low pressure hydraulic oil to the back pressure chamber 5. Therefore, the low pressure groove 34b can efficiently reduce the frictional force generated between the vane 3 and the inner circumferential cam surface 4a in a region where the change in the amount of protrusion of the vane 3 is small.

According to the present embodiment described above, the following effects are achieved.

In the vane pump 100, the first back pressure groove 34 communicates with the back pressure chamber 5 in the suction regions 42a, 42c, and the high pressure groove 34a guides high pressure hydraulic oil to the back pressure chamber 5 on the rear side in the rotational direction of the rotor 2, and the low pressure The groove 34b guides low-pressure hydraulic oil to the back pressure chamber 5 on the forward side of the rotor 2 in the rotational direction. As a result, in a region where the change in the amount of protrusion of the vane 3 is small, the force that presses the vane 3 toward the inner cam surface 4a becomes smaller, and the frictional force generated between the vane 3 and the inner cam surface 4a becomes smaller. Become. In addition, in a region where the change in the amount of protrusion of the vane 3 is small, the vane 3 can be protruded with a small force and brought into sliding contact with the inner circumferential cam surface 4a, so even if the pressure of the hydraulic oil in the back pressure chamber 5 is small, the vane pump It does not affect the operation of 100. This reduces the loss of rotational torque of the rotor 2 and improves the operating efficiency of the vane pump 100.

In the vane pump 100, as the rotor 2 rotates, the low pressure groove 34b begins to communicate with the back pressure chamber 5 at a position corresponding to the boundary 143 between the first curved surface 141 and the second curved surface 142. The low pressure groove 34b communicates with the back pressure chamber 5 from a region where the change in the amount of protrusion of the vane 3 begins to decrease as the rotor 2 rotates, and guides low pressure hydraulic oil to the back pressure chamber 5. Therefore, the low pressure groove 34b can efficiently reduce the frictional force generated between the vane 3 and the inner circumferential cam surface 4a in a region where the change in the amount of protrusion of the vane 3 is small.

Next, a modification of this embodiment will be described. The following modified examples are also within the scope of the present invention, and it is also possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the following different modified examples. It is.

<Modification 1>
In the embodiment described above, the low pressure groove 34b is provided so as to start communicating with the back pressure chamber 5 at a position corresponding to the boundary 143 between the first curved surface 141 and the second curved surface 142 as the rotor 2 rotates. However, the present invention is not limited thereto, and the low pressure groove 34b may be provided in the suction regions 42a, 42c at a position further forward in the rotational direction of the rotor 2 than the high pressure groove 34a. Further, in the embodiment described above, the high pressure groove 34a and the low pressure groove 34b are provided separately so as not to communicate with each other. The present invention is not limited to this, and the high pressure groove 34a and the low pressure groove 34b may be provided so as to communicate with each other via a throttle or the like. Furthermore, in the embodiment described above, the first back pressure groove 34 is composed of two grooves: a high pressure groove 34a and a low pressure groove 34b. However, the first back pressure groove 34 may be composed of three or more grooves. Even in this case, the first back pressure groove 34 is provided in the suction regions 42a, 42c so that the groove located on the front side in the rotational direction of the rotor 2 guides the low pressure working fluid to the back pressure chamber 5. Even with these configurations, the same effects as in the above embodiment can be achieved.

<Modification 2>
In the embodiment described above, the communication groove 37 is provided in a straight line between the low pressure groove 34b and the suction port 33. However, the communication groove 37 is not limited to this, and the communication groove 37 may be provided in an arc shape. Further, the communication groove 37 does not necessarily have to be provided between the low pressure groove 34b and the suction port 33, as long as the working fluid having a lower pressure than the working fluid guided to the high pressure groove 34a can be guided to the low pressure groove 34b. For example, the communication groove 37 may have any configuration as long as it guides the low-pressure working fluid from the low-pressure chamber 21 to the low-pressure groove 34b. Even with these configurations, the same effects as in the above embodiment can be achieved.

<Modification 3>
In the embodiment described above, the vane pump 100 includes a body-side side plate 30 as a side member that is provided on one axial end of the rotor 2 and is provided in contact with one side of the cam ring 4, and a body-side side plate 30 that is provided on the other axial end of the rotor 2. A cover-side side plate 40 is provided on the rotor 2 and contacts the other side surface of the rotor 2 and the cam ring 4. However, the vane pump 100 may not include the cover-side side plate 40 and may have a configuration in which the cam ring 4 is in contact with and sandwiched between the pump cover 20 and the body-side side plate 30.

<Modification 4>
In the embodiment described above, the slits 2s are provided to extend radially along the radial direction of the rotor 2. The slit 2s is not limited to this, and the slit 2s may be provided in a straight line and deviated from the radial direction of the rotor 2. For example, the slits 2s may be provided in the rotor 2 in a spiral shape.

Hereinafter, the configuration, operation, and effects of the embodiments of the present invention will be collectively described.

The vane pump 100 includes a rotor 2 that is rotationally driven, a plurality of slits 2s that open on the outer peripheral surface of the rotor 2, a plurality of vanes 3 that are slidably housed in the slits 2s, and a rotor 2 that is driven to rotate. A cam ring 4 having an inner circumferential cam surface 4a on which the tip 3a of the vane 3 slides, a body-side side plate 30 as a side member provided in contact with one side of the cam ring 4, a rotor 2, a cam ring 4, and a pair of The body-side side plate 30 has a pump chamber 6 partitioned by adjacent vanes 3 and a back pressure chamber 5 partitioned by the base end 3b of the vane 3 in the slit 2s. has a first back pressure groove 34 as a back pressure groove that communicates with the back pressure chamber 5 in the suction regions 42a, 42c where the gas expands. The high pressure groove 34a as a groove and the high pressure groove 34a guide the working fluid to the back pressure chamber 5 on the forward side in the rotational direction of the rotor 2 rather than the back pressure chamber 5 where the high pressure groove 34a leads the working fluid. It has a low pressure groove 34b as a second groove that guides the low pressure working fluid to the back pressure chamber 5, and the working fluid flows into the back pressure chamber 5 from the high pressure groove 34a or the low pressure groove 34b as the rotor 2 rotates. is selectively guided.

In this configuration, the first back pressure groove 34 communicates with the back pressure chamber 5 in the suction regions 42a, 42c, and the high pressure groove 34a guides high pressure working fluid to the back pressure chamber 5 on the rear side in the rotational direction of the rotor 2, and the low pressure The groove 34b guides low-pressure working fluid to the back pressure chamber 5 on the forward side of the rotor 2 in the rotational direction. Therefore, in the suction regions 42a and 42c, in the region where the change in the amount of protrusion of the vane 3 is large (the rear side in the rotational direction of the rotor 2), the pressure of the working fluid guided to the back pressure chamber 5 is high, and the change in the amount of protrusion of the vane 3 is In a region where the pressure is small (on the front side in the rotational direction of the rotor 2), the pressure of the working fluid guided to the back pressure chamber 5 is low. As a result, in a region where the change in the amount of protrusion of the vane 3 is small, the force that presses the vane 3 toward the inner cam surface 4a becomes smaller, and the frictional force generated between the vane 3 and the inner cam surface 4a becomes smaller. Become. In addition, in a region where the change in the amount of protrusion of the vane 3 is small, the vane 3 can be protruded with a small force and brought into sliding contact with the inner circumferential cam surface 4a, so even if the pressure of the working fluid in the back pressure chamber 5 is small, the vane pump It does not affect the operation of 100. This reduces the loss of rotational torque of the rotor 2 and improves the operating efficiency of the vane pump 100.

Furthermore, in the vane pump 100, the low pressure groove 34b is provided separately from the high pressure groove 34a so as not to communicate with the high pressure groove 34a.

In this configuration, by dividing the first back pressure groove 34 into a high pressure groove 34a and a low pressure groove 34b, friction generated between the vane 3 and the inner circumferential cam surface 4a in a region where the change in the protrusion amount of the vane 3 is small. force can be reduced.

Furthermore, in the vane pump 100, the body-side side plate 30 further includes a suction port 33 that guides the working fluid to the pump chamber 6, and a communication groove 37 that communicates the low pressure groove 34b and the suction port 33.

In this configuration, the low pressure groove 34b and the suction port 33 communicate with each other through the communication groove 37, so that low pressure working fluid can be guided to the low pressure groove 34b.

Furthermore, in the vane pump 100, the communication groove 37 is provided offset from the direction in which the slit 2s extends.

Further, in the vane pump 100, the slits 2s are provided to extend radially along the radial direction of the rotor 2, and the communication grooves 37 are provided to extend linearly, shifted from the radial direction of the rotor 2.

With these configurations, it is possible to prevent the communication groove 37 from interfering with the sliding movement of the vane 3 within the slit 2s.

In the vane pump 100, the inner cam surface 4a is a first curved surface that is provided in the suction regions 42a, 42c and whose radial dimension with respect to the rotor 2 increases by a constant amount of change along the rotational direction of the rotor 2. 141, which is continuous with the first curved surface 141 and is provided in the suction regions 42a, 42c on the forward side in the rotational direction of the rotor 2 than the first curved surface 141, and is radially spaced from the rotor 2 along the rotational direction of the rotor 2. As the rotor 2 rotates, the low-pressure groove 34b has a second curved surface 142 in which the amount of change in dimensions becomes smaller. Begins communication with chamber 5.

In this configuration, the amount of change in the radial dimension of the second curved surface 142 relative to the rotor 2 along the rotational direction of the rotor 2 is small. Therefore, when the vane 3 makes sliding contact with the second curved surface 142, the amount of protrusion of the vane 3 changes little with the rotation of the rotor 2. Therefore, the low pressure groove 34b communicates with the back pressure chamber 5 from the region where the change in the amount of protrusion of the vane 3 begins to decrease as the rotor 2 rotates, and guides the low pressure working fluid to the back pressure chamber 5. Therefore, the low pressure groove 34b can efficiently reduce the frictional force generated between the vane 3 and the inner circumferential cam surface 4a in a region where the change in the amount of protrusion of the vane 3 is small.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. do not have.

2... Rotor, 2s... Slit, 3... Vane, 3a... Tip part, 3b... Base end part, 4... Cam ring, 4a... Inner circumference cam surface, 5... ... Back pressure chamber, 6... Pump chamber, 30... Body side side plate (side member), 33... Suction port, 34... First back pressure groove (back pressure groove), 34a. ...High pressure groove (first groove), 34b...Low pressure groove (second groove), 37...Communication groove, 42a, 42c...Suction area, 141...First curved surface, 142... Second curved surface, 143... Boundary, 100... Vane pump

Claims (6)

a rotor that is rotationally driven;
a plurality of slits opening on the outer peripheral surface of the rotor;
a plurality of vanes slidably housed in the slit;
a cam ring having an inner circumferential cam surface with which the tip of the vane slides in contact as the rotor rotates;
a side member provided in contact with one side of the cam ring;
a pump chamber defined by the rotor, the cam ring, and a pair of adjacent vanes;
a back pressure chamber defined within the slit by a base end of the vane;
The side member has a back pressure groove that communicates with the back pressure chamber in a suction region where the volume of the pump chamber expands;
The back pressure groove is
a first groove that guides working fluid to the back pressure chamber;
The first groove guides the working fluid to the back pressure chamber on the forward side in the rotational direction of the rotor than the back pressure chamber into which the working fluid is guided, and the working fluid has a lower pressure than the working fluid guided by the first groove. a second groove leading to the back pressure chamber;
The vane pump is characterized in that working fluid is selectively introduced into the back pressure chamber from the first groove or the second groove as the rotor rotates. The vane pump according to claim 1,
The vane pump is characterized in that the second groove is provided separately from the first groove so as not to communicate with the first groove. The vane pump according to claim 2,
The vane pump is characterized in that the side member further includes a suction port that guides working fluid into the pump chamber, and a communication groove that communicates the second groove with the suction port. The vane pump according to claim 3,
The vane pump is characterized in that the communication groove is provided offset from the direction in which the slit extends. The vane pump according to claim 4,
The slit is provided to extend radially along the radial direction of the rotor,
The vane pump is characterized in that the communication groove is provided so as to extend in a straight line and deviate from the radial direction of the rotor. The vane pump according to claim 2,
The inner cam surface has a first curved surface that is provided in the suction region and whose radial dimension with respect to the rotor increases by a constant amount of change along the rotational direction of the rotor;
The amount of change in radial dimension between the rotor and the rotor along the rotation direction of the rotor, which is continuous with the first curved surface and is provided in the suction region on the front side in the rotational direction of the rotor than the first curved surface. has a second curved surface where
The vane pump is characterized in that the second groove starts communicating with the back pressure chamber at a position corresponding to a boundary between the first curved surface and the second curved surface as the rotor rotates.