Vane pump

Abstract

A vane pump (100) is provided with: a main body-side panel (30) having a plurality of first back pressure grooves (34) which are provided so as to be spaced apart from each other in the circumferential direction of a rotor (2), each of the first back pressure grooves (34) being open in a first sliding contact surface (30a) in which a rotor (2) is in sliding contact, and which communicate with a back pressure chamber (5), and a cover-side panel (40) having a plurality of second back pressure grooves (44) which are provided so as to be spaced apart from each other in the circumferential direction of the rotor (2); a plurality of first back pressure grooves (34) communicating with the back pressure chamber so as to open on a second sliding contact surface (40a) in which the rotor (2) is in sliding contact, and provided in the same number as the plurality of first back pressure grooves (34); and communication grooves (45) that are provided so as to open in the second sliding contact surface (40a) and that communicate a plurality of second back pressure grooves (44) that are adjacent in the circumferential direction, the opening area of each of the plurality of first back pressure grooves (34) facing the first sliding contact surface (30a) being larger than the opening area of each of the plurality of second back pressure grooves (44) facing the second sliding contact surface (40a).

Description

Technical Field

[0001] The invention relates to a vane pump. Background Art

[0002] In Japanese Patent Laid-Open No. JP2017-61904A, a vane pump is disclosed, which comprises: a rotor, which is driven to rotate; a main body side side panel, which is arranged at one axial end side of the rotor; a cover side side panel, which is arranged at the other axial end side of the rotor; a plurality of slits, which have openings on the outer periphery of the rotor and are formed radially; blades, which are accommodated and installed in each slit in a free sliding manner and are arranged between the main body side side panel and the cover side side panel; and a pump chamber, which is divided between the rotor and adjacent blades.

[0003] In the slit, a back pressure chamber is divided by the base end of the blade. The side panel on the main body side has: a pair of back pressure ports, which are formed in a manner opposite to each other with a through hole through which a drive shaft for rotating the rotor is inserted; a pair of back pressure grooves, which are arranged at positions offset by approximately 90 degrees with the through hole as the center relative to the pair of back pressure ports, and the pair of back pressure ports and the pair of back pressure grooves are respectively connected to the back pressure chamber. The side panel on the cover side has: four arc-shaped back pressure grooves, which are formed in a manner to connect adjacent back pressure chambers; and connecting grooves, which connect adjacent back pressure grooves. Summary of the invention

[0004] In the vane pump described in Japanese Patent Laid-Open JP2017-61904A, a pair of back pressure ports and a pair of back pressure grooves on the main body side panel and four back pressure grooves on the cover side panel become corresponding structures. However, the structure corresponding to the connecting groove of the cover side panel is not provided on the main body side panel. Therefore, compared with the main body side panel, the rotor is subjected to a load from the cover side panel side that is greater than the load of the working fluid guided to the connecting groove. Thereby, there is the possibility that the rotor is pressed toward the main body side panel and contacts, and the friction force generated between the rotor and the main body side panel affects the operation of the vane pump.

[0005] An object of the present invention is to stabilize the operation of a vane pump.

[0006] According to one embodiment of the present invention, a vane pump comprises: a rotor that is driven to rotate; a plurality of slits that open on the outer peripheral surface of the rotor; a plurality of blades that are accommodated and mounted in the slits in a freely slidable manner; a cam ring that has an inner peripheral cam surface, and the top ends of the blades slide in contact with the inner peripheral cam surface as the rotor rotates; a first side member that is arranged to contact the side surface of one side of the cam ring; a second side member that is arranged to contact the side surface of the other side of the cam ring; a pump chamber that is divided by the rotor, the cam ring, and a pair of adjacent blades; a back pressure chamber that is divided in the slit by the base ends of the blades, the first side member having a back pressure chamber that is respectively provided for the rotor to slide The first sliding contact surface of the dynamic contact is opened to communicate with the back pressure chamber, and a plurality of first back pressure grooves are arranged in a manner spaced apart from each other in the circumferential direction of the rotor, and the second side member has: a plurality of second back pressure grooves, which are connected to the back pressure chamber in a manner of opening on the second sliding contact surface with which the rotor is in sliding contact, respectively, and are arranged to be the same in number as the plurality of first back pressure grooves; a connecting groove, which is arranged to open on the second sliding contact surface and connect the plurality of second back pressure grooves adjacent in the circumferential direction, and the opening area of ​​each of the plurality of first back pressure grooves opening toward the first sliding contact surface is larger than the opening area of ​​each of the plurality of second back pressure grooves opening toward the second sliding contact surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a cross-sectional view of a vane pump according to an embodiment of the present invention.

[0008] Figure 2 It is a front view of the rotor, the vanes and the cam ring, which shows the state in which the rotor, the vanes and the cam ring are assembled together.

[0009] Figure 3 This is a front view of the side panel of the main body viewed from the pump cover side.

[0010] Figure 4 This is a front view of the cover side panel viewed from the pump cover side.

[0011] Figure 5 This is a front view of the cover side panel viewed from the rotor side.

[0012] Figure 6 This is a front view of a cover-side side panel according to a modified example of the embodiment of the present invention as seen from the rotor side. DETAILED DESCRIPTION

[0013] Hereinafter, a vane pump according to an embodiment of the present invention will be described with reference to the accompanying drawings. The vane pump is used as a fluid pressure supply source for a fluid pressure device (e.g., a power steering device, a transmission, etc.) mounted on a vehicle. Here, although a vane pump in which working oil is used as a working fluid is described, other fluids such as working water may also be used as the working fluid.

[0014] like Figure 1 as well as Figure 2 As shown, the vane pump 100 comprises: a pump body 10 having a receiving recess 10A; a pump cover 20 covering the receiving recess 10A and being fixed to the pump body 10; a drive shaft 1 supported by the pump body 10 and the pump cover 20 in a freely rotatable manner through bearings 11 and 12; a rotor 2 connected to the drive shaft 1 and driven to rotate; a plurality of slits 2s opening on the outer peripheral surface of the rotor 2; a plurality of vanes 3 accommodated in the slits 2s of the rotor 2 in a freely slidable manner; and a cam ring 4 having an inner peripheral cam surface 4a, with which the top end 3a of the vane 3 comes into sliding contact as the rotor 2 rotates. The cam ring 4 accommodates the rotor 2 and the vanes 3.

[0015] The vane pump 100 is driven by a driving device (not shown) such as an engine, and a rotor 2 connected to a driving shaft 1 is connected to the vane pump 100. Figure 2 The piston is driven counterclockwise as shown by the arrow, thereby generating fluid pressure.

[0016] Hereinafter, the direction along the rotation axis of the rotor 2 is referred to as the “axial direction”, the radial direction centered on the rotation axis of the rotor 2 is referred to as the “radial direction”, and the direction in which the rotor 2 rotates when the vane pump 100 is operating is referred to as the “rotation direction”.

[0017] like Figure 1 As shown, the vane pump 100 also includes: a main body side panel 30 as a first side member, which is arranged at one axial end side of the rotor 2 and is arranged to contact the side of one side of the rotor 2 and the cam ring 4; and a cover side panel 40 as a second side member, which is arranged at the other axial end side of the rotor 2 and is arranged to contact the side of the other side of the rotor 2 and the cam ring 4.

[0018] The body side side panel 30 is provided between the bottom surface of the receiving recess 10A and the rotor 2. The body side side panel 30 is in sliding contact with one axial end surface of the rotor 2, and abuts against one axial end surface of the cam ring 4. The cover side side panel 40 is provided between the rotor 2 and the pump cover 20. The cover side side panel 40 is in sliding contact with the other axial end surface of the rotor 2, and abuts against the other axial end surface of the cam ring 4.

[0019] Thus, the body side panel 30 and the cover side panel 40 are arranged to face both side surfaces of the rotor 2 and the cam ring 4. That is, the body side panel 30 and the cover side panel 40 are arranged to sandwich the rotor 2 and the cam ring 4 in the axial direction.

[0020] The body side panel 30, the rotor 2, the cam ring 4, and the cover side panel 40 are housed in the housing recess 10A of the pump body 10. In this state, since the pump cover 20 is attached to the pump body 10, the housing recess 10A is sealed.

[0021] like Figure 2 As shown, a plurality of slits 2s are radially formed on the rotor 2. The slits 2s open on the outer circumference of the rotor 2.

[0022] The blade 3 is formed in a rectangular flat plate shape. The blade 3 is inserted into each slit 2s in a freely slidable manner, and has a top end 3a as an end in the direction protruding from the slit 2s, and a base end 3b as an end on the opposite side of the top end 3a. In the slit 2s, a back pressure chamber 5 is divided by the base end 3b of the blade 3. As described later, the back pressure chamber 5 is connected to the high pressure chamber 14, and the working oil is guided from the high pressure chamber 14 to the back pressure chamber 5. The blade 3 is pressed in the direction protruding from the slit 2s by the pressure of the working oil guided to the back pressure chamber 5.

[0023] The cam ring 4 is an annular member including an inner circumferential cam surface 4a having a substantially oval inner circumferential surface and pin holes 4b for inserting positioning pins 8. The inner circumferential cam surface 4a is a surface with which the top ends 3a of the plurality of vanes 3 come into sliding contact as the rotor 2 rotates.

[0024] When the rotor 2 rotates, a centrifugal force is generated on the blade 3. The blade 3 is pressed in the direction protruding from the slit 2s by the centrifugal force. That is, the blade 3 is pressed in the direction protruding from the slit 2s (radially outward) by the fluid pressure of the back pressure chamber 5 pressing the base end 3b and the centrifugal force acting along with the rotation of the rotor 2. When the blade 3 is pressed radially outward, the top end 3a of the blade 3 slides in contact with the inner peripheral cam surface 4a of the cam ring 4. Thereby, inside the cam ring 4, the pump chamber 6 is divided by the outer peripheral surface of the rotor 2, the inner peripheral cam surface 4a of the cam ring 4, and a pair of adjacent blades 3.

[0025] The inner peripheral cam surface 4a is formed into a substantially elliptical shape. Therefore, the volume of the pump chamber 6 repeatedly expands and contracts with the rotation of the rotor 2. In the expansion area (suction area) where the pump chamber 6 expands, the working oil is sucked in, and in the contraction area (discharge area) where the pump chamber 6 contracts, the working oil is discharged.

[0026] like Figure 1As shown, on the bottom surface side of the pump housing recess 10A of the pump body 10, the pump body 10 and the main body side panel 30 define an annular high pressure chamber 14. The high pressure chamber 14 is provided between the bottom surface of the housing recess 10A and the main body side panel 30, and stores high pressure working oil ejected from the pump chamber 6. The high pressure chamber 14 is connected to the external fluid pressure device 70 (e.g., a power steering device, a transmission, etc.) of the vane pump 100 via the ejection passage 62. The ejection passage 62 is, for example, a passage provided on the vane pump 100 side.

[0027] The pump cover 20 has a low pressure chamber 21, and the inner peripheral surface of the housing recess 10A has a bypass passage 13 connected to the low pressure chamber 21. The bypass passage 13 is provided at two positions facing each other across the cam ring 4. The low pressure chamber 21 is connected to the fluid tank 60 via a suction passage 61.

[0028] like Figure 1 as well as Figure 2 As shown, the cam ring 4 has cutouts 4c and 4d extending from the outer peripheral surface to the inner peripheral cam surface 4a. The cutout 4c opens on the side adjacent to the body side panel 30, and the cutout 4d opens on the side adjacent to the cover side panel 40.

[0029] Figure 3 4 is a front view of the side panel 30 of the main body as viewed from the cam ring 4 side. Figure 3 As shown, the side panel 30 of the main body is a plate-shaped component including a first sliding contact surface 30a that is in sliding contact with the side surface of the blade 3, a first discharge port 31 formed in a manner corresponding to the discharge areas 50b and 50d, a first through hole 32 for the drive shaft 1 to pass through, a first suction port 33 formed in a manner corresponding to the suction areas 50a and 50c, and a pin hole 39 for the positioning pin 8 to pass through.

[0030] The first ejection port 31 is provided at two positions opposite to each other across the first through hole 32. The first ejection port 31 is formed in an arc shape with the first through hole 32 as the center. The first ejection port 31 penetrates the main body side panel 30 and communicates with the high pressure chamber 14 formed in the pump body 10. The first ejection port 31 guides the working oil guided from the pump chamber 6 to the high pressure chamber 14. The working oil flowing into the high pressure chamber 14 is supplied to the fluid pressure device 70 (see FIG. 1 ) outside the vane pump 100 via the ejection passage 62. Figure 1 ).

[0031] The first suction port 33 is provided at two positions opposite to each other across the first through hole 32. The first suction port 33 is formed at a position of the receiving recess 10A corresponding to the detour passage 13. The first suction port 33 is formed in a concave shape opening radially outward. The outer peripheral end of the first suction port 33 reaches the outer peripheral surface of the main body side panel 30.

[0032] like Figure 1 As shown, in the state where the main body side side panel 30 is assembled to the cam ring 4, the first suction port 33 of the main body side side panel 30 faces the notch portion 4c of the cam ring 4. The working oil in the bypass passage 13 is guided to the pump chamber 6 through the notch portion 4c and the first suction port 33. The first suction port 33 guides the working oil from the low pressure chamber 21 to the pump chamber 6.

[0033] like Figure 3 As shown, a groove-shaped recess 36 is formed on the first sliding contact surface 30a of the side panel 30 on the main body side. The recess 36 is provided at the end of the connection start side where the pump chamber 6 in the first ejection port 31 starts to communicate with the rotation of the rotor 2, and is connected to the first ejection port 31. The recess 36 is formed in such a way that the opening area gradually increases toward the rotation direction of the rotor 2. By forming the recess 36, the working oil is supplied to the pump chamber 6 through the recess 36 in the stage before the pump chamber 6 directly opens on the first ejection port 31. Thereby, the pump chamber 6 is pressurized, thereby preventing a sudden pressure change in the high-pressure chamber 14.

[0034] The main body side panel 30 has a plurality of first back pressure grooves 34 that are opened on the first sliding contact surface 30a and communicate with the back pressure chamber 5, and are arranged in a manner spaced apart from each other in the circumferential direction of the rotor 2. In the present embodiment, one first back pressure groove 34 is provided in each of the suction area 50a, 50c and the discharge area 50b, 50d, so that a total of four are provided. The plurality of first back pressure grooves 34 are respectively provided in the same shape. The first back pressure grooves 34a, 34c provided in the suction area 50a, 50c are provided to face each other across the first through hole 32, and the first back pressure grooves 34b, 34d (discharge side first back pressure grooves) provided in the discharge area 50b, 50d are provided to face each other across the first through hole 32. The first back pressure groove 34 is provided between the first through hole 32 and the first discharge port 31. Specifically, the first back pressure groove 34b provided in the ejection area 50b is provided between the first ejection port 31 and the first through hole 32 provided in the same ejection area 50b. The same is true for the first back pressure groove 34d provided in the ejection area 50d. In other words, the first ejection port 31 is provided so that the first back pressure grooves 34b and 34d provided in the ejection areas 50b and 50d are located between the first ejection port 31 and the first through hole 32. The opening area of ​​each of the plurality of first back pressure grooves 34 opening toward the first sliding contact surface 30a is larger than the opening area of ​​each of the plurality of second back pressure grooves 44 described later of the cover side panel 40 opening toward the second sliding contact surface 40a. Details of the opening area of ​​the first back pressure groove 34 will be described later.

[0035] The first back pressure groove 34 is communicated with the plurality of back pressure chambers 5 in an overlapping manner as the rotor 2 rotates. The first back pressure groove 34 is communicated with the high pressure chamber 14 provided so as to penetrate the main body side panel 30. Thereby, the high pressure working oil from the first discharge port 31 is guided to the back pressure chamber 5 via the high pressure chamber 14 and the first back pressure groove 34. The back pressure chamber 5 presses the vane 3 toward the inner peripheral cam surface 4a by the working oil guided via the first back pressure groove 34, so that the vane 3 is brought into sliding contact with the inner peripheral cam surface 4a.

[0036] Figure 4 FIG. 4 is a front view of the cover side panel 40 as viewed from the pump cover 20 side. Figure 4 As shown, the cover side panel 40 is a plate-shaped member having a second through hole 42 for inserting the drive shaft 1, a second suction port 43 as a suction port for guiding the working oil to the pump chamber 6, and a pin hole 49 for inserting the positioning pin 8. The cover side panel 40 is positioned relative to the cam ring 4 and the main body side panel 30 by the positioning pin 8.

[0037] The second suction ports 43 are provided in the suction areas 50a and 50c, respectively, and are provided at two positions facing each other with the second through hole 42 interposed therebetween. The second suction ports 43 are formed at positions of the receiving recess 10A corresponding to the detour passage 13. The second suction ports 43 are provided to open radially outward. Figure 1 As shown, when the cover side panel 40 is assembled to the cam ring 4, the second suction port 43 of the cover side panel 40 faces the notch 4d of the cam ring 4. The hydraulic oil in the bypass passage 13 and the low pressure chamber 21 is guided to the pump chamber 6 via the second suction port 43 and the notch 4d.

[0038] Figure 5 4 is a front view of the cover side panel 40 as viewed from the rotor 2 side. Figure 5 As shown, the cover side panel 40 has: a second sliding contact surface 40a, which is in sliding contact with the side surface of the blade 3; a second ejection port 41, which is formed in a manner corresponding to each area of ​​the ejection area 50b, 50d; a plurality of second back pressure grooves 44, which are connected to the back pressure chamber 5 in a manner of opening on the second sliding contact surface 40a, and are provided in the same number as the plurality of first back pressure grooves 34; and a connecting groove 45, which is provided to open on the second sliding contact surface 40a and connect the plurality of second back pressure grooves 44 adjacent in the circumferential direction. The second ejection port 41, the second back pressure groove 44, the connecting groove 45, and the recess 46 described later provided in the second ejection port 41 do not penetrate the cover side panel 40 in the axial direction.

[0039] The second ejection port 41 is provided at two positions opposed to each other with the second through hole 42 therebetween. In addition, a notch 46 is provided at the end of the second ejection port 41 on the communication start side where the pump chamber 6 starts to communicate with the rotation of the rotor 2. The second ejection port 41 and the notch 46 are provided to correspond to the first ejection port 31 and the notch 36. Specifically, the second ejection port 41 is provided to overlap with the first ejection port 31 in the axial direction, and is provided with the same number in the same size as the first ejection port 31. The notch 46 is provided to overlap with the notch 36 in the axial direction, and is provided with the same number in the same size as the notch 36. Unlike the first ejection port 31, the second ejection port 41 is not directly connected to the high pressure chamber 14.

[0040] The second discharge port 41 is connected to the first discharge port 31 via the pump chamber 6, so the same pressure as that of the first discharge port 31 acts on the second discharge port 41. Since the second discharge port 41 is arranged to face the first discharge port 31 with the blade 3 interposed therebetween, the force acting on the blade 3 by the pressure in the first discharge port 31 is offset by the pressure in the second discharge port 41. This prevents the blade 3 from being pressed against the cover-side side panel 40 by the pressure in the first discharge port 31.

[0041] The second back pressure grooves 44 are arranged in a manner spaced apart from each other in the circumferential direction of the rotor 2, and one is provided in each of the suction regions 50a, 50c and the discharge regions 50b, 50d. The plurality of second back pressure grooves 44 are respectively provided in the same shape. The second back pressure grooves 44 are provided to correspond to the first back pressure grooves 34. Specifically, the second back pressure grooves 44 are provided to overlap with the first back pressure grooves 34 in the axial direction, and the same number as the first back pressure grooves 34 is provided. The second back pressure grooves 44 are provided between the second through hole 42 and the second discharge port 41. Specifically, the second back pressure groove 44b (discharge side second back pressure groove) provided in the discharge region 50b is provided between the second discharge port 41 and the second through hole 42 provided in the same discharge region 50b. The same is true for the second back pressure groove 44d provided in the discharge region 50d. In other words, the second discharge port 41 is provided so that the second back pressure grooves 44b, 44d (discharge side first back pressure grooves) provided in the discharge regions 50b, 50d are located between the second discharge port 41 and the second through hole 42. In addition, in the present embodiment, the second back pressure grooves 44b, 44d provided in the discharge regions 50b, 50d are provided so that the radial dimension between the second back pressure grooves 44b, 44d and the second discharge port 41, that is, the outer dimension B, is larger than the radial dimension between the second back pressure grooves 44b, 44d and the second through hole 42, that is, the inner dimension A. The second back pressure grooves 44a, 44c provided in the suction regions 50a, 50c are also provided in the same shape.

[0042] A plurality of connecting grooves 45 are provided in an arc shape, and connect the second back pressure groove 44a with the second back pressure groove 44b, the second back pressure groove 44b with the second back pressure groove 44c, the second back pressure groove 44c with the second back pressure groove 44d, and the second back pressure groove 44d with the second back pressure groove 44a. All of the plurality of second back pressure grooves 44 are connected to each other through the connecting grooves 45. An annular groove opening toward the rotor 2 is formed on the cover side panel 40 through the second back pressure grooves 44 and the connecting grooves 45. The radial dimension of the opening of the connecting groove 45 on the second sliding contact surface 40a is smaller than the radial dimension of the opening of each back pressure groove of the plurality of second back pressure grooves 44 on the second sliding contact surface 40a. The second back pressure groove 44 and the connecting groove 45 are connected to the back pressure chamber 5, and are not connected to the low pressure chamber 21.

[0043] The working oil supplied to the back pressure chamber 5 from the first back pressure groove 34 of the body side panel 30 is supplied to all the back pressure chambers 5 via the second back pressure groove 44 and the communication groove 45 of the cover side panel 40. Therefore, the working oil ejected from the pump chamber 6 is supplied to all the back pressure chambers 5. Therefore, all the vanes 3 of the vane pump 100 rotate while the tip end 3a is in sliding contact with the inner peripheral cam surface 4a of the cam ring 4.

[0044] Thus, in the main body side panel 30 and the cover side panel 40, the first and second discharge ports 31 and 41, the first and second suction ports 33 and 43, and the first and second back pressure grooves 34 and 44 correspond to each other and are arranged at positions overlapping in the axial direction.

[0045] In addition, in the pump body side panel 30, the first back pressure groove 34 opens on the first sliding contact surface 30a, and the high-pressure working oil from the first discharge port 31 is guided to the first back pressure groove 34 via the high-pressure chamber 14. Therefore, the rotor 2 receives a load from the main body side panel 30 side by the pressure of the working oil guided to the first back pressure groove 34. In addition, in the cover side panel 40, the second back pressure groove 44 and the connecting groove 45 open on the second sliding contact surface 40a, and the high-pressure working oil from the high-pressure chamber 14 is guided to the second back pressure groove 44 and the connecting groove 45 via the first back pressure groove 34 of the main body side panel 30 and the back pressure chamber 5. Therefore, the rotor 2 receives a load from the cover side panel 40 side by the pressure of the working oil guided to the second back pressure groove 44 and the connecting groove 45.

[0046] Here, in the vane pump 100, as described above, the first back pressure groove 34 of the main body side panel 30 and the second back pressure groove 44 of the cover side panel 40 become corresponding structures. However, the structure corresponding to the connecting groove 45 of the cover side panel 40 is not provided on the main body side panel 30. Therefore, when it is assumed that the opening area of ​​the first back pressure groove 34 and the second back pressure groove 44 toward the rotor 2 is the same, the rotor 2 receives a load corresponding to the pressure of the working oil guided to the connecting groove 45 from the cover side panel 40 side compared with the main body side panel 30 side. Thereby, there is a possibility that the rotor 2 is pressed toward the main body side panel 30 and contacts, and the friction force generated between the rotor 2 and the main body side panel 30 affects the operation of the vane pump 100. In addition, the gap between the rotor 2 and the cover side panel 40 becomes larger, so the working oil may also leak from between the two. Thus, in the vane pump 100 of the present embodiment, the opening area of ​​the first back-pressure groove 34 facing the rotor 2 is provided to be larger than that of each of the plurality of second back-pressure grooves 44 .

[0047] Next, the opening area of ​​the first back pressure groove 34 will be described.

[0048] The radial dimension of the rotor 2 at the opening of the first back pressure groove 34 toward the first sliding contact surface 30a is larger than the radial dimension of the rotor 2 at the opening of the second back pressure groove 44 toward the second sliding contact surface 40a. Specifically, the first back pressure groove 34 is provided so that when the inner dimension A in the cover side panel 40 is larger than the outer dimension B, the dimension between the first through hole 32 is smaller than the inner dimension A, and when the outer dimension B in the cover side panel 40 is larger than the inner dimension A, the dimension between the first discharge port 31 is smaller than the outer dimension B. In other words, the first back pressure groove 34 has a shape obtained by expanding the second back pressure groove 44 toward the larger one of the inner dimension A and the outer dimension B. In the vane pump 100 of the present embodiment, the outer dimension B in the cover side panel 40 is larger than the inner dimension A, and therefore, the first back pressure groove 34 is provided so that the dimension between the first discharge port 31 is smaller than the outer dimension B. That is, the first back-pressure groove 34 becomes such a shape that the second back-pressure groove 44 expands toward the second ejection port 41. The shape of the first through-hole 32 side in the first back-pressure groove 34 (in other words, the shape of the inner circumferential surface of the first back-pressure groove 34) is the same as the shape of the second through-hole 42 side in the second back-pressure groove 44 (in other words, the shape of the inner circumferential surface of the second back-pressure groove 44). The inner circumferential surface of the first back-pressure groove 34 and the inner circumferential surface of the second back-pressure groove 44 overlap in the axial direction. In addition, when the inner dimension A in the cover-side side panel 40 is greater than the outer dimension B, the first back-pressure groove 34 becomes such a shape that the second back-pressure groove 44 expands toward the second through-hole 42, and the outer circumferential surface of the first back-pressure groove 34 and the outer circumferential surface of the second back-pressure groove 44 overlap in the axial direction.

[0049] In addition, the total opening area obtained by adding the opening areas of the respective openings of the first sliding contact surface 30a of the plurality of first back pressure grooves 34 is the same as the total opening area of ​​the plurality of second back pressure grooves 44 and the connecting groove 45. In other words, the opening area of ​​the first back pressure groove 34 is set to be larger than that of the second back pressure groove 44 by an amount corresponding to the opening area of ​​the connecting groove 45.

[0050] Thus, in the vane pump 100, the opening area of ​​the openings of the plurality of first back pressure grooves 34 toward the first sliding contact surface 30a is larger than the opening area of ​​the openings of the plurality of second back pressure grooves 44 toward the second sliding contact surface 40a. Therefore, even if the cover side panel 40 has the connecting groove 45 in addition to the second back pressure groove 44, the load borne by the rotor 2 from the main body side panel 30 side and the load borne from the cover side panel 40 side by the pressure of the working oil are balanced. In particular, in the vane pump 100 of the present embodiment, the load borne by the rotor 2 from the main body side panel 30 side and the load borne from the cover side panel 40 side by the pressure of the working oil can be balanced. Thereby, the situation where the rotor 2 is pressed toward the main body side panel 30 and contacts is prevented, and the operation of the vane pump 100 is stable.

[0051] In addition, the first back pressure groove 34 is arranged to be enlarged relative to the second back pressure groove 44 in a manner that reduces the larger dimension of the inner dimension A and the outer dimension B. Thus, the first back pressure groove 34 can be made larger than the second back pressure groove 44 without reducing the smaller dimension of the inner dimension A and the outer dimension B. Therefore, the radial dimension between the first back pressure groove 34 and the first through hole 32, which is the area where the rotor 2 slides in contact, and the radial dimension between the first back pressure groove 34 and the first discharge port 31 can be ensured to be larger. This prevents the working oil from leaking from the sliding contact surface between the first back pressure groove 34 and the first through hole 32 and the rotor 2, and from the sliding contact surface between the first back pressure groove 34 and the first discharge port 31 and the rotor 2. As a result, the operation of the vane pump 100 is further stabilized.

[0052] Next, the operation of the vane pump 100 will be described.

[0053] When the drive shaft 1 is driven to rotate by the power of a drive device such as an engine (not shown), the rotor 2 Figure 2 The pump chamber 6 located in the suction area 50a, 50c expands as the rotor 2 rotates. Figure 1As shown in FIG. 1 , the working oil in the fluid box 60 is sucked into the pump chamber 6 via the suction passage 61, the low pressure chamber 21, the first suction port 33, and the second suction port 43 of the cover side panel 40. In addition, the pump chamber 6 located in the discharge area 50b, 50d contracts as the rotor 2 rotates. As a result, the working oil in the pump chamber 6 is discharged via the first discharge port 31 (see FIG. 1 ). Figure 2 ) and is ejected to the high pressure chamber 14. The working oil ejected to the high pressure chamber 14 is supplied to the external fluid pressure device 70 via the ejection passage 62. In the vane pump 100 of the present embodiment, during one rotation of the rotor 2, each pump chamber 6 repeatedly performs two times of suction and ejection of the working oil.

[0054] A portion of the working oil ejected to the high-pressure chamber 14 is supplied to the back-pressure chamber 5 via the first back-pressure groove 34, and presses the base end 3b of the vane 3 toward the inner peripheral cam surface 4a. In addition, the working oil supplied to the back-pressure chamber 5 is supplied to all the back-pressure chambers 5 via the second back-pressure groove 44 and the connecting groove 45 of the cover-side side panel 40. Therefore, the vane 3 is pressed in the direction of protruding from the slit 2s by the fluid pressure of the back-pressure chamber 5 pressing the base end 3b and the centrifugal force acting with the rotation of the rotor 2. Thereby, since the top end 3a of the vane 3 rotates while sliding in contact with the inner peripheral cam surface 4a of the cam ring 4, the working oil in the pump chamber 6 is ejected from the first ejection port 31 in a manner that does not leak from between the top end 3a of the vane 3 and the inner peripheral cam surface 4a of the cam ring 4.

[0055] According to the present embodiment described above, the following effects are achieved.

[0056] In the vane pump 100, the opening area of ​​the openings of the plurality of first back pressure grooves 34 toward the first sliding contact surface 30a is larger than the opening area of ​​the openings of the plurality of second back pressure grooves 44 toward the second sliding contact surface 40a. Therefore, even if the cover side panel 40 has the connecting groove 45 in addition to the second back pressure groove 44, the load borne by the rotor 2 from the main body side panel 30 side and the load borne from the cover side panel 40 side due to the pressure of the working oil are balanced. In particular, in the vane pump 100, the load borne by the rotor 2 from the main body side panel 30 side and the load borne from the cover side panel 40 side due to the pressure of the working oil can be balanced. Thereby, the rotor 2 is prevented from being pressed toward the main body side panel 30 and contacting, and the operation of the vane pump 100 is stable.

[0057] In the vane pump 100, the first back pressure groove 34 is arranged to be enlarged in a manner that the larger dimension of the inner dimension A and the outer dimension B is reduced relative to the second back pressure groove 44. Therefore, even if the opening area of ​​the first back pressure groove 34 is increased, the radial dimension between the first back pressure groove 34 and the first through hole 32, which is the area where the rotor 2 slides in contact, and the radial dimension between the first back pressure groove 34 and the first discharge port 31 can be ensured to be large. This prevents the working oil from leaking from the sliding contact surface between the first back pressure groove 34 and the first through hole 32 and the rotor 2, and the sliding contact surface between the first back pressure groove 34 and the first discharge port 31 and the rotor 2. As a result, the operation of the vane pump 100 is further stabilized.

[0058] The following modifications are also within the scope of the present invention, and it is possible to combine the configurations shown in the modifications with the configurations described in the above embodiment, or to combine the configurations described in the following different modifications with each other.

[0059] <Variation 1>

[0060] In the above-mentioned embodiment, the total opening area of ​​each of the plurality of first back pressure grooves 34 opening toward the first sliding contact surface 30a is the same as the total opening area of ​​the plurality of second back pressure grooves 44 and the connecting groove 45. However, if the first back pressure groove 34 is a structure in which the opening area of ​​the first sliding contact surface 30a is larger than that of each of the plurality of second back pressure grooves 44, the total opening area may be different from the total opening area of ​​the plurality of second back pressure grooves 44 and the connecting groove 45. In other words, the load borne by the rotor 2 from the side panel 30 of the main body side and the load borne from the side panel 40 of the cover side by the pressure of the working oil may not be completely balanced. Even with this structure, the pressure of the working oil guided to the first back pressure groove 34 can be used to buffer the load applied to the rotor 2 by the working oil guided to the second back pressure groove 44 and the connecting groove 45.

[0061] In addition, in the above-mentioned embodiment, the main body side side panel 30 is provided between the rotor 2 and the high pressure chamber 14. Therefore, the following situation can also be considered, that is, the main body side side panel 30 receives a load from the bottom surface side of the receiving recess 10A of the pump body 10 toward the rotor 2 side by the pressure of the working oil in the high pressure chamber 14, and bends toward the rotor 2 side. When the main body side side panel 30 bends toward the rotor 2 side, the distance (axial distance) between the rotor 2 and the main body side side panel 30 becomes smaller. In contrast, when the total opening area of ​​the plurality of first back pressure grooves 34 is made larger than the total opening area of ​​the plurality of second back pressure grooves 44 and the connecting groove 45, the load received by the rotor 2 from the main body side side panel 30 side by the pressure of the working oil is larger than the load received from the cover side side panel 40 side. Thereby, the rotor 2 is placed close to the cover side side panel 40, and the distance between the rotor 2 and the main body side side panel 30 can be ensured. Therefore, even in the vane pump 100 in which the body-side side panel 30 is bent toward the rotor 2 side, the rotor 2 is prevented from coming into contact with the body-side side panel 30 and the cover-side side panel 40 .

[0062] <Variation 2>

[0063] In the above embodiment, the opening area of ​​the plurality of first back pressure grooves 34 toward the first sliding contact surface 30a is set larger than that of each of the plurality of second back pressure grooves 44, and the load borne by the rotor 2 from the body side side panel 30 side and the load borne from the cover side side panel 40 side by the pressure of the working oil are balanced. In addition, as Figure 6 As shown, the connecting groove 45 may also be a structure connected to the second suction port 43. A groove 48 connected to the second suction port 43 is provided on the second back pressure groove 44, and the connecting groove 45 is connected to the second suction port 43 via the groove 48 and the second back pressure groove 44. The groove 48 is arranged to be offset from the radial direction of the rotor 2 in a manner that does not hinder the sliding of the blades 3 in the slit 2s. The groove 48 is connected to the second suction port 43, so that the pressure of the working oil in the connecting groove 45 is reduced. As a result, the load on the rotor 2 from the working oil guided to the connecting groove 45 is reduced, and the difference between the load on the rotor 2 from the side panel 30 of the main body side due to the pressure of the working oil and the load on the side panel 40 of the cover side can be reduced. Thereby, the rotor 2 is prevented from contacting the side panel 30 of the main body side.

[0064] In addition, the groove 48 may be a structure that is provided in the connecting groove 45 and connects the connecting groove 45 and the second suction port 43. In addition, in this modification, the difference between the load borne by the rotor 2 from the main body side panel 30 side and the load borne from the cover side panel 40 side by the pressure of the working oil can be reduced, so the first back pressure groove 34 is provided so that the opening area toward the rotor 2 is the same as that of each of the plurality of second back pressure grooves 44. In addition, the second back pressure groove 44 and the connecting groove 45 may have the same width and be provided as a circular groove.

[0065] Hereinafter, the configuration, operation, and effects of the embodiments of the present invention will be summarized and described.

[0066] The vane pump 100 comprises: a rotor 2 which is driven to rotate; a plurality of slits 2s which are open on the outer peripheral surface of the rotor 2; a plurality of vanes 3 which are accommodated and mounted in the slits 2s in a freely slidable manner; a cam ring 4 which has an inner peripheral cam surface 4a, with the top end 3a of the vane 3 slidingly contacting the inner peripheral cam surface 4a as the rotor 2 rotates; a main body side side panel 30 which is a first side member and is arranged to contact one side surface of the cam ring 4; a cover side side panel 40 which is a second side member and is arranged to contact the other side surface of the cam ring 4; a pump chamber 6 which is divided by the rotor 2, the cam ring 4, and a pair of adjacent vanes 3; a back pressure chamber 5 which is divided by the base end 3b of the vane 3 in the slit 2s, and the main body side side panel 30 has a plurality of slits 2s and a plurality of slits 2s respectively provided on the supply side. The first sliding contact surface 30a with which the rotor 2 slides is open and communicates with the back pressure chamber 5, and a plurality of first back pressure grooves 34 are arranged in a manner spaced apart from each other in the circumferential direction of the rotor 2, and the cover side panel 40 has: a plurality of second back pressure grooves 44, which are communicated with the back pressure chamber 5 in a manner of opening on the second sliding contact surface 40a with which the rotor 2 slides, and are arranged in the same number as the plurality of first back pressure grooves 34; a connecting groove 45, which is arranged to open on the second sliding contact surface 40a and connects a plurality of second back pressure grooves 44 adjacent in the circumferential direction, and the opening area of ​​each of the plurality of first back pressure grooves 34 opening toward the first sliding contact surface 30a is larger than the opening area of ​​each of the plurality of second back pressure grooves 44 opening toward the second sliding contact surface 40a.

[0067] In this structure, the opening area of ​​the openings of the plurality of first back pressure grooves 34 toward the first sliding contact surface 30a is larger than the opening area of ​​the openings of the plurality of second back pressure grooves 44 toward the second sliding contact surface 40a. Therefore, even if the cover side panel 40 has the connecting groove 45 in addition to the second back pressure groove 44, the load on the rotor 2 from the main body side panel 30 side and the load on the cover side panel 40 side due to the pressure of the working fluid are balanced. This prevents the rotor 2 from being pressed toward the main body side panel 30 and contacting it, and the operation of the vane pump 100 is stable.

[0068] In the vane pump 100 , the radial dimension of the rotor 2 at the opening of the first back pressure groove 34 toward the first sliding contact surface 30 a is larger than the radial dimension of the rotor 2 at the opening of the second back pressure groove 44 toward the second sliding contact surface 40 a .

[0069] In addition, in the vane pump 100, the plurality of first back-pressure grooves 34 include discharge-side first back-pressure grooves 34b and 34d provided in the discharge areas 50b and 50d where the volume of the pump chamber 6 is contracted, and the plurality of second back-pressure grooves 44 include discharge-side second back-pressure grooves 44b and 44d provided in the discharge areas 50b and 50d. The discharge-side first back-pressure grooves 34b and 34d and the discharge-side second back-pressure grooves 44b and 44d are provided so as to overlap each other in the axial direction of the rotor 2. The main body side panel 30 has a first through hole 32 and a first discharge port 31, wherein the first through hole 32 is inserted through the drive shaft 1 for rotating the rotor 2, and the first discharge port 31 is provided so that the discharge-side first back-pressure grooves 34b and 34d are located between the first discharge port 31 and the first through hole 32. The cover side panel 40 has a second through hole 42 and a second discharge port 31. The outlet port 41, the second through hole 42 is for the drive shaft 1 to pass through, the second outlet port 41 is arranged so that the outlet-side second back pressure grooves 44b, 44d are located between the second outlet port 41 and the second through hole 42, the cover-side side panel 40 is arranged so that one of the radial dimensions between the outlet-side second back pressure grooves 44b, 44d and the second through hole 42, i.e., the inner dimension A and the radial dimension between the outlet-side second back pressure grooves 44b, 44d and the second outlet port 41, i.e., the outer dimension B is larger than the other, the outlet-side first back pressure grooves 34b, 34d are arranged so that, when the inner dimension A is larger than the outer dimension B, the radial dimension between the outlet-side first through hole 32 is smaller than the inner dimension A, and, when the outer dimension B is larger than the inner dimension A, the radial dimension between the outlet-side first outlet port 31 is smaller than the outer dimension B.

[0070] In the above structure, the first back pressure groove 34 is set to be larger than the second back pressure groove 44, that is, the inner dimension A and the outer dimension B. Therefore, even if the opening area of ​​the first back pressure groove 34 is increased, the radial dimension between the first back pressure groove 34 and the first through hole 32 and the radial dimension between the first back pressure groove 34 and the first discharge port 31 can be ensured to be large. This prevents the working fluid from leaking from the sliding contact surface between the first back pressure groove 34 and the first through hole 32 and the rotor 2, and from the sliding contact surface between the first back pressure groove 34 and the first discharge port 31 and the rotor 2.

[0071] In the vane pump 100 , the total opening area obtained by adding the opening areas of the plurality of first back pressure grooves 34 is equal to the total opening area of ​​the plurality of second back pressure grooves 44 and the communication groove 45 .

[0072] In this structure, the load received by the rotor 2 from the body-side side panel 30 side and the load received from the cover-side side panel 40 side can be balanced due to the pressure of the working fluid.

[0073] In addition, the vane pump 100 also includes: a pump body 10, which has a receiving recess 10A for receiving the rotor 2, the cam ring 4, the main body side panel 30, and the cover side panel 40; a pump cover 20, which covers the receiving recess 10A and is fixed to the pump body 10; a high-pressure chamber 14, which is arranged on the bottom side of the receiving recess 10A and is divided by the pump body 10 and the main body side panel 30, and stores high-pressure working fluid ejected from the pump chamber 6, the main body side panel 30 is arranged between the rotor 2 and the high-pressure chamber 14, and the total opening area of ​​the first back pressure groove 34 is larger than the total opening area of ​​the multiple second back pressure grooves 44 and the connecting grooves 45.

[0074] In this structure, the main body side side panel 30 receives a load from the bottom surface side of the receiving recess 10A of the pump main body 10 toward the rotor 2 side by the pressure of the working fluid in the high-pressure chamber 14, and bends toward the rotor 2 side. Therefore, the distance between the rotor 2 and the main body side side panel 30 becomes smaller. However, by making the total opening area of ​​the plurality of first back pressure grooves 34 larger than the total opening area of ​​the plurality of second back pressure grooves 44 and the connecting grooves 45, the load received by the rotor 2 from the main body side side panel 30 side by the pressure of the working oil is larger than the load received from the cover side side panel 40 side. Thereby, the rotor 2 is positioned close to the cover side side panel 40, and therefore, even in the vane pump 100 in which the main body side side panel 30 bends toward the rotor 2 side, the rotor 2 is prevented from contacting the main body side side panel 30 and the cover side side panel 40.

[0075] In the vane pump 100 , the cover-side side panel 40 further includes a suction port 43 for introducing the working fluid into the pump chamber 6 , and the communication groove 45 communicates with the suction port 43 .

[0076] In this structure, since the communication groove 45 is connected to the suction port 43, the pressure of the working fluid in the communication groove 45 becomes smaller. As a result, the load on the rotor 2 from the working fluid guided to the communication groove 45 becomes smaller, and the difference between the load on the rotor 2 from the main body side panel 30 side and the load on the cover side panel 40 side due to the pressure of the working fluid can be reduced. This prevents the rotor 2 from contacting the main body side panel 30.

[0077] Although the embodiments of the present invention have been described above, the above embodiments merely represent a part of 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.

[0078] This application claims the priority based on Japanese Patent Application No. 2022-106446 filed with the Japan Patent Office on June 30, 2022, and all the contents of the application are incorporated into this specification by reference.

Claims

1. A vane pump, wherein: have: a rotor, which is driven in rotation; a plurality of slits opening on an outer peripheral surface of the rotor; A plurality of blades are accommodated and installed in the slit in a freely slidable manner; a cam ring having an inner peripheral cam surface, with the tip end of the vane being in sliding contact with the inner peripheral cam surface as the rotor rotates; a first side member disposed to contact a side surface of one side of the cam ring; a second side member disposed so as to contact the other side surface of the cam ring; a pump chamber divided by the rotor, the cam ring, and a pair of adjacent blades; a back pressure chamber defined by the base end of the blade in the slit, The first side member has a plurality of first back pressure grooves which are respectively opened on a first sliding contact surface with which the rotor slides and communicate with the back pressure chamber and are arranged at intervals in the circumferential direction of the rotor. The second side member has: a plurality of second back pressure grooves, which are connected to the back pressure chamber in a manner of opening on the second sliding contact surface with which the rotor is in sliding contact, and are provided in the same number as the plurality of first back pressure grooves; a connecting groove, which is provided to open on the second sliding contact surface and connects the plurality of second back pressure grooves adjacent to each other in the circumferential direction, An opening area of ​​each of the plurality of first back pressure grooves that opens toward the first sliding contact surface is larger than an opening area of ​​each of the plurality of second back pressure grooves that opens toward the second sliding contact surface.

2. The vane pump according to claim 1, wherein: A radial dimension of the rotor at the opening of the first back pressure groove facing the first sliding contact surface is larger than a radial dimension of the rotor at the opening of the second back pressure groove facing the second sliding contact surface.

3. The vane pump according to claim 2, wherein: The plurality of first back pressure grooves include a discharge-side first back pressure groove provided in a discharge region where the volume of the pump chamber is contracted. The plurality of second back pressure grooves include a discharge-side second back pressure groove provided in the discharge region, The discharge-side first back-pressure groove and the discharge-side second back-pressure groove are provided so as to overlap each other in the axial direction of the rotor. The first side member has a first through hole and a first discharge port, the first through hole being inserted with a drive shaft for rotating the rotor, and the first discharge port being arranged so that the discharge-side first back pressure groove is located between the first discharge port and the first through hole. The second side member has a second through hole and a second discharge port, the second through hole is for the drive shaft to pass through, and the second discharge port is arranged so that the discharge-side second back pressure groove is located between the second discharge port and the second through hole. The second side member is configured so that one of the radial dimension between the second back pressure groove on the discharge side and the second through hole, i.e., the inner dimension, and the radial dimension between the second back pressure groove on the discharge side and the second discharge port, i.e., the outer dimension, is larger than the other. The first back pressure groove on the discharge side is configured so that, when the inner dimension is larger than the outer dimension, the radial dimension between the first through hole is smaller than the inner dimension, and is configured so that, when the outer dimension is larger than the inner dimension, the radial dimension between the first discharge port is smaller than the outer dimension.

4. The vane pump according to claim 1, wherein: A total opening area obtained by adding the respective opening areas of the plurality of first back pressure grooves is equal to a total opening area of ​​the plurality of second back pressure grooves and the communication groove.

5. The vane pump according to claim 1, wherein: Also available: a pump body having a housing recess for housing the rotor, the cam ring, the first side member, and the second side member; A pump cover, which covers the receiving recess and is fixed to the pump body; a high-pressure chamber which is provided on the bottom surface side of the accommodating recessed portion and is partitioned by the pump body and the first side member and stores the high-pressure working fluid ejected from the pump chamber, The first side member is disposed between the rotor and the high pressure chamber. A total opening area obtained by adding the respective opening areas of the plurality of first back-pressure grooves is greater than a total opening area of ​​the plurality of second back-pressure grooves and the communicating groove.

6. The vane pump according to claim 1, wherein: The second side member also has a suction port for guiding the working fluid to the pump chamber. The communication groove is communicated with the suction port.

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