Vane pump
By introducing high-pressure and low-pressure backpressure grooves into the vane pump, the contact force between the vane and the inner peripheral cam surface is adjusted, and the problem of increased friction force of the vane pump under high pressure conditions is solved and the working efficiency is improved.
Patent Information
- Application Number
- CN202380040496.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-06-24
- Filing Date
- 2023-05-24
- Publication Date
- 2024-12-31
AI Technical Summary
Under the conditions of high-pressure working fluid, the friction between the blade and the inner peripheral cam surface increases, resulting in a loss of rotational torque and a decrease in working efficiency of the rotor.
The first backpressure groove and the second backpressure groove are introduced into the vane pump. The first backpressure groove guides the high-pressure working fluid to the backpressure chamber, and the second backpressure groove guides the low-pressure working fluid to the backpressure chamber, so that the blades are protruding in a protruding amount. The less-changing area contacts the inner peripheral cam surface to reduce friction.
The friction between the blade and the inner peripheral cam surface is effectively reduced, the loss of rotor rotation torque is reduced, and the working efficiency of the blade pump is improved.
Smart Images
Figure CN119234091A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a vane pump. Background Art
[0002] In Japanese Patent Publication JP2020-41484A, a vane pump is disclosed, which has: a rotor, which is driven to rotate; a plurality of slits, which are opened on the outer peripheral surface of the rotor; a plurality of blades, which are accommodated and installed in the slits in a free sliding manner; a cam ring, which has an inner peripheral cam surface, and the top ends of the plurality of blades are in sliding contact with the inner peripheral cam surface as the rotor rotates; a pair of side parts, which are configured to clamp the rotor and the cam ring; a pump chamber, which is divided by the rotor, the cam ring, the adjacent blades, and a pair of side parts. The back pressure chamber is divided by the inner peripheral surface of the slit and the base end of the blade, and the high-pressure working fluid is guided to the back pressure chamber from the ejection port of the side part set on one side. The blade is pressed in the direction of protruding from the slit by the fluid pressure of the back pressure chamber pressing the base end and the centrifugal force acting with the rotation of the rotor, and the top end of the blade is in sliding contact with the inner peripheral cam surface of the cam ring. Thereby, the blade protrudes from the slit as the rotor rotates, and the volume of the pump chamber expands. Summary of the invention
[0003] In the vane pump described in Japanese Patent Laid-Open No. JP2020-41484A, when the pressure of the working oil introduced into the back pressure chamber is high, the vanes are pressed strongly toward the inner peripheral cam surface, so the friction force generated between the vanes and the inner peripheral cam surface becomes larger. As a result, there is a possibility that a loss is generated in the rotational torque of the rotor, and the working efficiency of the vane pump is reduced.
[0004] The object of the present invention is to improve the working efficiency of a vane pump.
[0005] 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 vanes 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 end of the vane is in sliding contact with the inner peripheral cam surface as the rotor rotates; a side member that is arranged to contact one side surface of the cam ring; a pump chamber that is divided by the rotor, the cam ring, and a pair of adjacent vanes; and a back pressure chamber that is divided in the slit by the base end of the vane. The side member has a back-pressure groove connected to the back-pressure chamber in the suction area of the pump chamber where the volume expands, and the back-pressure groove has: a first groove that guides the working fluid to the back-pressure chamber; a second groove that guides the working fluid to the back-pressure chamber that is on the front side of the rotation direction of the rotor compared to the back-pressure chamber to which the working fluid is guided by the first groove, and guides the working fluid with a lower pressure than the working fluid guided by the first groove 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. BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Figure 1 It is a cross-sectional view of a vane pump according to an embodiment of the present invention.
[0007] 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.
[0008] Figure 3 for Figure 2 An enlarged view of the transfer portion of the inner peripheral cam surface.
[0009] Figure 4 It is a graph showing the relationship between the protrusion amount of the vanes and the rotation amount of the rotor in the suction region.
[0010] Figure 5 This is the front view of the side panel of the main body.
[0011] Figure 6 The front view of the cover side panel. DETAILED DESCRIPTION
[0012] 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.
[0013] like Figure 1 as well as Figure 2As shown, the vane pump 100 comprises: a pump body 10, which is formed with a pump receiving recess 10A; a pump cover 20, which covers the opening of the pump receiving recess 10A and is fixed to the pump body 10; a drive shaft 1, which is supported by the pump body 10 and the pump cover 20 in a freely rotatable manner through bearings 11 and 12; a rotor 2, which is connected to the drive shaft 1 and is driven to rotate; a plurality of slits 2s, which are opened on the outer peripheral surface of the rotor 2; a plurality of vanes 3, which are accommodated and installed in the slits 2s in a freely slidable manner; and a cam ring 4, which has an inner peripheral cam surface 4a, and the top end 3a of the vane 3 is in sliding contact with the inner peripheral cam surface 4a as the rotor 2 rotates. The cam ring 4 accommodates the rotor 2 and the vanes 3.
[0014] 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.
[0015] 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”.
[0016] like Figure 1 As shown, the vane pump 100 also includes: a main body side side panel 30 as a side component, which is arranged at one axial end side of the rotor 2 and is arranged to contact one side of the rotor 2 and the cam ring 4; a cover side side panel 40, which is arranged at the other axial end side of the rotor 2 and abuts against the other side of the rotor 2 and the cam ring 4.
[0017] The body side side panel 30 is provided between the bottom surface of the pump housing 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.
[0018] 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.
[0019] The body side panel 30, the rotor 2, the cam ring 4, and the cover side panel 40 are housed in the pump housing recess 10A of the pump body 10. In this state, since the pump cover 20 is attached to the pump body 10, the pump housing recess 10A is sealed.
[0020] like Figure 2 As shown, the rotor 2 is provided with a plurality of slits 2s extending radially in the radial direction of the rotor 2. The openings of the slits 2s are formed in a raised portion 23 raised from the outer periphery of the rotor 2 toward the radially outer side.
[0021] The blade 3 is formed in a rectangular flat plate shape. The blade 3 is inserted into the 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 or the low pressure chamber 21, and the working oil is guided from the high pressure chamber 14 or the low pressure chamber 21 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.
[0022] 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.
[0023] 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.
[0024] 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.
[0025] like Figure 2As shown, the vane pump 100 involved in this embodiment has a first suction area 42a and a first discharge area 42b where the vane 3 performs a first reciprocating movement, and a second suction area 42c and a second discharge area 42d where the vane 3 performs a second reciprocating movement. During one rotation of the rotor 2, the pump chamber 6 expands in the first suction area 42a, contracts in the first discharge area 42b, expands in the second suction area 42c, and contracts in the second discharge area 42d. Although the vane pump 100 has two suction areas 42a and 42c and two discharge areas 42b and 42d, it is not limited thereto, and may be configured to have a structure having one or more than three suction areas and one or more than three discharge areas.
[0026] The inner peripheral cam surface 4a includes: a first curved surface 141, which is provided in each of the suction areas 42a and 42c, and the radial dimension between the first curved surface 141 and the rotor 2 increases by a certain amount along the rotation direction of the rotor 2; and a second curved surface 142, which is continuous with the first curved surface 141 and is provided in each of the suction areas 42a and 42c on the front side of the first curved surface 141 in the rotation direction of the rotor 2, and the radial dimension between the second curved surface 142 and the rotor 2 changes less than the first curved surface 141 along the rotation direction of the rotor 2. The boundary between the first curved surface 141 and the second curved surface 142 is referred to as a boundary 143.
[0027] Specifically, the radial dimension between the first curved surface 141 and the rotor 2 is the radial dimension between the portion where the slit 2s opens in the rotor 2 and the first curved surface 141. For example, when the first curved surface 141 is used as an example, Figure 3 As shown, the radial dimension between the first curved surface 141 and the rotor 2 is the radial dimension A between the raised portion 23 of the rotor 2 and the first curved surface 141. Figure 3 In the figure, for the sake of convenience, the description of the structure provided on the side panel 30 of the main body is omitted. In other words, the radial dimension between the first curved surface 141 and the rotor 2 is equivalent to the protrusion amount of the blade 3 from the slit 2s of the rotor 2. In addition, the change amount of the radial dimension between the first curved surface 141 and the rotor 2 is equivalent to the change in the protrusion amount of the blade 3. The same is true for the second curved surface 142.
[0028] The blade 3 protrudes from the slit 2s in a manner that it spans from the first curved surface 141 to the second curved surface 142 until the protrusion reaches the maximum amount. The first curved surface 141 is set so that the radial dimension between the blade 3 and the rotor 2 increases by a certain amount along the rotation direction of the rotor 2. Therefore, when the blade 3 is in sliding contact with the first curved surface 141 as the rotor 2 rotates, Figure 4As shown, the blade 3 protrudes from the slit 2s at a constant speed. In addition, the second curved surface 142 is configured so that the amount of change in the radial dimension between the blade 3 and the rotor 2 decreases along the rotation direction of the rotor 2. Therefore, when the blade 3 passes through the boundary 143 and is in sliding contact with the second curved surface 142, the speed at which the blade 3 protrudes from the slit 2s gradually decreases. When the protrusion amount of the blade 3 is the largest, the speed at which the blade 3 protrudes from the slit 2s is zero. In this way, in the suction areas 42a and 42c, the protrusion amount of the blade 3 changes more on the rear side in the rotation direction of the rotor 2, and the protrusion amount of the blade 3 changes less on the front side in the rotation direction of the rotor 2.
[0029] like Figure 1 As shown, on the bottom surface side of the pump housing recess 10A of the pump body 10, the pump body 10 and the body side side panel 30 define an annular high pressure chamber 14. The high pressure chamber 14 is connected to a fluid pressure device 70 (e.g., 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.
[0030] The pump cover 20 is provided with a low pressure chamber 21, and the inner peripheral surface of the pump housing recess 10A is provided with a bypass passage 13 communicating with 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.
[0031] 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.
[0032] Figure 5 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-like component including a sliding contact surface 30a that slides in contact with the side surface of the blade 3, an ejection port 31 formed in a manner corresponding to the ejection areas 42b and 42d, a through hole 32 for the drive shaft 1 to pass through, an intake port 33 formed in a manner corresponding to the intake areas 42a and 42c, and a pin hole 39 for the positioning pin 8 to pass through.
[0033] The discharge port 31 is provided at two positions facing each other with the through hole 32 interposed therebetween. The discharge port 31 is formed in an arc shape with the through hole 32 as the center. The discharge port 31 penetrates the main body side panel 30 and communicates with the high pressure chamber 14 formed in the pump body 10. The discharge port 31 guides the working oil discharged 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 discharge passage 62. Figure 1 ).
[0034] The suction port 33 is provided at two positions facing each other with the through hole 32 interposed therebetween. The suction port 33 is formed at a position of the pump housing recess 10A corresponding to the bypass passage 13. The suction port 33 is formed in a concave shape opening radially outward. The outer peripheral end of the suction port 33 reaches the outer peripheral surface of the main body side panel 30.
[0035] like Figure 1 As shown, in the state where the main body side panel 30 is assembled to the cam ring 4, the suction port 33 of the main body side panel 30 faces the notch 4c of the cam ring 4. The working oil in the bypass passage 13 is guided to the pump chamber 6 through the notch 4c and the suction port 33. The suction port 33 guides the working oil from the low pressure chamber 21 to the pump chamber 6.
[0036] like Figure 3 As shown, a groove-shaped recess 36 is formed on the sliding contact surface 30a of the side panel 30 on the main body side. The recess 36 is provided at the end of the discharge port 31 on the communication start side where the pump chamber 6 starts to communicate with the rotation of the rotor 2, and is connected to the discharge 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 discharge port 31. Thereby, the pump chamber 6 is pressurized, thereby preventing a sudden pressure change in the high-pressure chamber 14.
[0037] The side panel 30 on the main body side has: a first back pressure groove 34 as a pair of back pressure grooves, which are respectively arranged in the suction areas 42a and 42c; a second back pressure groove 35, which is respectively arranged in the discharge areas 42b and 42d; and a connecting groove 37, which connects the low pressure groove 34b described later of the first back pressure groove 34 and the suction port 33. The back pressure grooves 34 and 35 are arranged in an arc shape centered on the through hole 32 and open on the sliding surface 30a. The pair of first back pressure grooves 34 are arranged in a manner opposite to each other with the through hole 32 sandwiched therebetween. The pair of second back pressure grooves 35 are arranged in a position offset by approximately 90° with the through hole 32 as the center relative to the pair of first back pressure grooves 34. The back pressure grooves 34 and 35 are connected to the plurality of back pressure chambers 5 in an overlapping manner as the rotor 2 rotates. The first back pressure groove 34 communicates with the back pressure chamber 5 in the suction regions 42 a and 42 c , and the second back pressure groove 35 communicates with the back pressure chamber 5 in the discharge regions 42 b and 42 d .
[0038] The first back pressure groove 34 includes: a high pressure groove 34a as a first groove, which guides the working oil to the back pressure chamber 5; and a low pressure groove 34b as a second groove, which is provided on the front side of the rotation direction of the rotor 2 compared with the high pressure groove 34a, and guides the working oil with a lower pressure than the working oil guided by the high pressure groove 34a to the back pressure chamber 5. The low pressure groove 34b is provided to be separated from the high pressure groove 34a in a manner not to communicate with the high pressure groove 34a. In the present embodiment, the first back pressure groove 34 is composed of two grooves, the high pressure groove 34a and the low pressure groove 34b.
[0039] The high pressure groove 34a is arranged in an arc shape. Figure 1 As shown in FIG. 1 , the high pressure groove 34 is connected to the high pressure chamber 14 provided in a manner penetrating the side panel 30 of the main body. In this way, the high pressure working oil from the discharge port 31 is guided to the back pressure chamber 5 via the high pressure chamber 14 and the high pressure groove 34a. The high pressure groove 34a is provided in an area corresponding to the first curved surface 141 of the inner peripheral cam surface 4a of the cam ring 4. Specifically, the high pressure groove 34a is provided so that Figure 2 In the front view shown, the first curved surface 141 is located on a straight line passing through the high-pressure groove 34a from the rotation center axis ○ of the rotor 2. That is, the back pressure chamber 5 presses the vane 3 toward the first curved surface 141 by the hydraulic oil guided through the high-pressure groove 34a, so that the vane 3 slides against the first curved surface 141.
[0040] The low-pressure groove 34b is arranged in an arc shape. The low-pressure groove 34b does not penetrate the main body side panel 30, and is not connected to the high-pressure chamber 14. The low-pressure groove 34b is connected to the suction port 33 via the connecting groove 37. Thereby, the low-pressure working oil from the discharge port 33 is guided to the back-pressure chamber 5 via the connecting groove 37 and the low-pressure groove 34b. The low-pressure groove 34b is arranged in an area corresponding to the second curved surface 142 of the inner peripheral cam surface 4a of the cam ring 4, and 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 as the rotor 2 rotates. Specifically, the low-pressure groove 34b is arranged so that Figure 2 In the front view shown, the second curved surface 142 is located on a straight line passing through the low-pressure groove 34b from the rotation center axis ○ of the rotor 2, and the boundary 143 is located on a straight line passing through the end of the low-pressure groove 34b on the rear side of the rotation direction from the rotation center axis ○. That is, the working oil guided to the back pressure chamber 5 via the low-pressure groove 34b presses the vane 3 toward the second curved surface 142, so that the vane 3 and the second curved surface 142 are in sliding contact. In this way, the low-pressure groove 34b guides the working fluid to the back pressure chamber 5 on the front side of the rotation direction of the rotor 2 compared to the back pressure chamber 5 to which the working oil is guided by the high-pressure groove 34a. In the vane pump 100 of this embodiment, the working oil is selectively guided to the back pressure chamber 5 from the high-pressure groove 34a or the low-pressure groove 34b as the rotor 2 rotates.
[0041] The connecting groove 37 is arranged to extend linearly in a manner spanning between the low-pressure groove 34b and the suction port 33, and is opened on the sliding contact surface 30a of the main body side panel 30. The connecting groove 37 does not penetrate the main body side panel 30, and is not connected to the high-pressure chamber 14. Therefore, only the low-pressure working oil from the suction port 33 is guided to the low-pressure groove 34b via the connecting groove 37. The connecting groove 37 is arranged to be offset from the direction in which the slit 2s extends. Specifically, the connecting groove 37 is arranged to be offset from the radial direction of the rotor 2. In the present embodiment, the connecting groove 37 is arranged to extend from the end of the low-pressure groove 34b on the rear side of the rotation direction of the rotor 2 to the suction port 33. As a result, the connecting groove 37 does not hinder the sliding of the blade 3 in the slit 2s. In addition, although the sliding of the blade 3 is not hindered, the connecting groove 37 can also be arranged along the direction in which the slit 2s extends.
[0042] The second back pressure groove 35 is connected to the high pressure chamber 14 provided so as to penetrate the main body side panel 30. Thus, the high pressure working oil from the discharge port 31 is guided to the back pressure chamber 5 via the high pressure chamber 14 and the second back pressure groove 35. The working oil guided to the back pressure chamber 5 via the second back pressure groove 35 presses the vane 3 toward the inner peripheral cam surface 4a in the discharge areas 42b and 42d, so that the vane 3 and the inner peripheral cam surface 4a are in sliding contact.
[0043] Figure 6 FIG. 4 is a front view of the cover side panel 40 as viewed from the pump cover 20 side. Figure 6 As shown, the cover side panel 40 has a sliding surface 40a (see Figure 1 ), a plate-shaped member including a through hole 42 for inserting the drive shaft 1, a notch 43 formed in a manner corresponding to the suction areas 42a, 42c, 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.
[0044] The notch 43 is provided at two positions facing each other with the through hole 42 interposed therebetween. The notch 43 is formed at a position of the pump housing recess 10A corresponding to the bypass passage 13. The notch 43 is provided so as to open radially outward. Figure 1 As shown, when cover side panel 40 is assembled to cam ring 4, notch 43 of cover side panel 40 faces notch 4d of cam ring 4. Working oil in bypass passage 13 and low pressure chamber 21 is guided to pump chamber 6 via notch 43 and notch 4d.
[0045] Thus, the pair of suction ports 33 are located in the suction regions 42a and 42c, and the pair of discharge ports 31 are located in the discharge regions 42b and 42d. The hydraulic oil is guided to the pump chamber 6 from both axial sides through the suction ports 33 and the cutouts 43 of the cover-side side panel 40.
[0046] Next, the operation of the vane pump 100 will be described.
[0047] 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 42a, 42c expands as the rotor 2 rotates. Figure 1 As 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 suction port 33, and the notch 43 of the cover side panel 40. In addition, the pump chamber 6 located in the discharge area 42b, 42d contracts as the rotor 2 rotates. As a result, the working oil in the pump chamber 6 is discharged via the 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 channel 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.
[0048] A portion of the working oil ejected to the high-pressure chamber 14 is supplied to the back pressure chamber 5 via the back pressure grooves 34 and 35, and presses the base end 3b of the vane 3 toward the inner peripheral cam surface 4a. 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 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.
[0049] Here, when the pressure of the working oil guided to the back pressure chamber is high, the vane is pressed strongly toward the inner peripheral cam surface, so the friction force generated between the vane and the inner peripheral cam surface becomes larger. Thereby, there is a possibility that a loss is generated in the rotational torque of the rotor, and the working efficiency of the vane pump is reduced. However, when the pressure of the working oil guided to the back pressure chamber is low, the vane cannot protrude toward the inner peripheral cam surface in the suction area and contact the inner peripheral cam surface, and the working oil in the pump chamber leaks from between the top end of the vane and the inner peripheral cam surface of the cam ring.
[0050] In contrast, 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 the high pressure working 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 low pressure working oil from the low pressure chamber 21 to the back pressure chamber 5 on the front side in the rotation direction of the rotor 2. In addition, in the suction regions 42a and 42c, the change in the protrusion amount of the vane 3 is large on the rear side in the rotation direction of the rotor 2, and the change in the protrusion amount of the vane 3 is small on the front side in the rotation direction of the rotor 2. Thus, in the suction regions 42a and 42c, in the region where the protrusion amount of the blade 3 changes greatly (the rear side in the rotation direction of the rotor 2), the pressure of the working oil guided to the back pressure chamber 5 is high, and in the region where the protrusion amount of the blade 3 changes less (the front side in the rotation direction of the rotor 2), the pressure of the working oil guided to the back pressure chamber 5 is low. Thus, in the region where the protrusion amount of the blade 3 changes less, the force pressing the blade 3 toward the inner peripheral cam surface 4a is small, and the friction force generated between the blade 3 and the inner peripheral cam surface 4a is small. In addition, in the region where the protrusion amount of the blade 3 changes less, the blade 3 can be protruded with a small force and slidably contacted with the inner peripheral cam surface 4a. Therefore, even if the pressure of the working oil in the back pressure chamber 5 in this region is small, it does not affect the operation of the vane pump 100. Thus, the loss of the rotation torque of the rotor 2 is small, and the working efficiency of the vane pump 100 is improved.
[0051] In the vane pump 100, the low-pressure groove 34b starts 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 as the rotor 2 rotates. Thus, the low-pressure groove 34b communicates with the back-pressure chamber 5 from a region where the change in the protrusion amount of the vane 3 caused by the rotation of the rotor 2 starts to decrease, and guides low-pressure working oil to the back-pressure chamber 5. Therefore, the low-pressure groove 34b can efficiently reduce the friction force generated between the vane 3 and the inner peripheral cam surface 4a in the region where the change in the protrusion amount of the vane 3 is small.
[0052] According to the present embodiment described above, the following effects are achieved.
[0053] In the vane pump 100, the first back pressure groove 34 is connected to the back pressure chamber 5 in the suction area 42a, 42c, and the high pressure groove 34a guides the high pressure working oil to the back pressure chamber 5 on the rear side of the rotation direction of the rotor 2, and the low pressure groove 34b guides the low pressure working oil to the back pressure chamber 5 on the front side of the rotation direction of the rotor 2. Thereby, in the area where the change of the protrusion amount of the blade 3 is small, the force pressing the blade 3 toward the inner peripheral cam surface 4a is small, and the friction force generated between the blade 3 and the inner peripheral cam surface 4a is small. In addition, in the area where the change of the protrusion amount of the blade 3 is small, the blade 3 can be protruded with a small force and slidably contacted with the inner peripheral cam surface 4a, so even if the pressure of the working oil in the back pressure chamber 5 is small, it does not affect the operation of the vane pump 100. Thereby, the loss of the rotation torque of the rotor 2 is small, and the working efficiency of the vane pump 100 is improved.
[0054] In the vane pump 100, the low-pressure groove 34b starts 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 as the rotor 2 rotates. The low-pressure groove 34b communicates with the back-pressure chamber 5 from a region where the change in the protrusion amount of the vane 3 caused by the rotation of the rotor 2 starts to decrease, and guides low-pressure working oil to the back-pressure chamber 5. Therefore, the low-pressure groove 34b can efficiently reduce the friction force generated between the vane 3 and the inner peripheral cam surface 4a in the region where the change in the protrusion amount of the vane 3 is small.
[0055] 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.
[0056] <Variation 1>
[0057] In the above embodiment, the low-pressure groove 34b is arranged 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. Without limitation to this, the low-pressure groove 34b only needs to be arranged in the suction area 42a, 42c on the front side of the rotation direction of the rotor 2 compared with the high-pressure groove 34a. In addition, in the above embodiment, the high-pressure groove 34a and the low-pressure groove 34b are separately arranged in a non-communicating manner. Without limitation to this, the high-pressure groove 34a and the low-pressure groove 34b may also be arranged to communicate via a throttle portion or the like. In addition, in the above embodiment, the first back pressure groove 34 is composed of two grooves, the high-pressure groove 34a and the low-pressure groove 34b. Without limitation to this, the first back pressure groove 34 is composed of a plurality of grooves of three or more. Even in this case, the first back pressure groove 34 is arranged so that in the suction area 42a, 42c, the groove located on the front side of the rotation direction of the rotor 2 guides the low-pressure working fluid to the back pressure chamber 5. Even with the above-mentioned structure, the same effects as those of the above-mentioned embodiment are achieved.
[0058] <Variation 2>
[0059] In the above embodiment, the connecting groove 37 is arranged in a straight line in a manner spanning between the low-pressure groove 34b and the suction port 33. It is not limited to this, and the connecting groove 37 may also be arranged in an arc shape. In addition, if the connecting groove 37 can guide the working fluid with a lower pressure than the working fluid guided to the high-pressure groove 34a to the low-pressure groove 34b, it may not necessarily be arranged to span between the low-pressure groove 34b and the suction port 33. For example, the connecting groove 37 only needs to be a structure that guides the low-pressure working fluid from the low-pressure chamber 21 to the low-pressure groove 34b. Even with the above structure, the same effect as the above embodiment is achieved.
[0060] <Variation 3>
[0061] In the above embodiment, the vane pump 100 further includes: a body-side side panel 30 as a side member, which is provided at one axial end side of the rotor 2 and is provided so as to contact one side surface of the cam ring 4; and a cover-side side panel 40, which is provided at the other axial end side of the rotor 2 and abuts against the other side surface of the rotor 2 and the cam ring 4. However, the vane pump 100 may be a structure in which the cam ring 4 is sandwiched by the pump cover 20 and the body-side side panel 30 in a manner in contact with each other without the cover-side side panel 40.
[0062] <Variation 4>
[0063] In the above embodiment, the slits 2s are provided to extend radially in the radial direction of the rotor 2. The present invention is not limited thereto, and the slits 2s may be provided linearly so as to be offset in the radial direction of the rotor 2. For example, the slits 2s may be provided in the rotor 2 in a spiral shape.
[0064] Hereinafter, the configuration, operation, and effects of the embodiments of the present invention will be summarized and described.
[0065] 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, and the top end 3a of the vane 3 comes into sliding contact with the inner peripheral cam surface 4a as the rotor 2 rotates; a main body side side panel 30 which is a side member and is arranged to come into contact with one 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 pump chamber 6 ... pump chamber 6 which is divided by the base end 3b of the vane 3 in the slit 2s, and the pump chamber 6 which is divided by the base end 3b of the vane 3 in the slit 2s The first back pressure groove 34 as a back pressure groove connected to the back pressure chamber 5 in the suction area 42a, 42c of the volume expansion of the chamber 6 has: a high-pressure groove 34a as a first groove, which guides the working fluid to the back pressure chamber 5; a low-pressure groove 34b as a second groove, which guides the working fluid to the back pressure chamber 5 on the front side of the rotation direction of the rotor 2 compared with the back pressure chamber 5 to which the working fluid is guided by the high-pressure groove 34a, and guides the working fluid with a lower pressure than the working fluid guided by the high-pressure groove 34a to the back pressure chamber 5, and the working fluid is selectively guided to the back pressure chamber 5 from the high-pressure groove 34a or the low-pressure groove 34b as the rotor 2 rotates.
[0066] In this structure, the first back pressure groove 34 is connected to the back pressure chamber 5 in the suction area 42a, 42c, and the high pressure groove 34a guides the high pressure working fluid to the back pressure chamber 5 on the rear side of the rotation direction of the rotor 2, and the low pressure groove 34b guides the low pressure working fluid to the back pressure chamber 5 on the front side of the rotation direction of the rotor 2. Therefore, in the suction area 42a, 42c, in the area where the change of the protrusion amount of the blade 3 is large (the rear side of the rotation direction of the rotor 2), the pressure of the working fluid guided to the back pressure chamber 5 is high, and in the area where the change of the protrusion amount of the blade 3 is small (the front side of the rotation direction of the rotor 2), the pressure of the working fluid guided to the back pressure chamber 5 is low. Thereby, in the area where the change of the protrusion amount of the blade 3 is small, the force pressing the blade 3 toward the inner peripheral cam surface 4a is small, and the friction force generated between the blade 3 and the inner peripheral cam surface 4a is small. In addition, in the region where the protrusion amount of the vane 3 changes less, the vane 3 can be protruded with less force and slidably contact the inner peripheral cam surface 4a, so even if the pressure of the working fluid in the back pressure chamber 5 is small, it does not affect the operation of the vane pump 100. Thereby, the loss of the rotational torque of the rotor 2 is small, and the working efficiency of the vane pump 100 is improved.
[0067] In addition, in the vane pump 100 , the low-pressure groove 34 b is provided separately from the high-pressure groove 34 a so as not to communicate with the high-pressure groove 34 a .
[0068] In this structure, by dividing the first back pressure groove 34 into the high pressure groove 34a and the low pressure groove 34b, the friction force generated between the blade 3 and the inner peripheral cam surface 4a can be reduced in the region where the change in the protrusion amount of the blade 3 is small.
[0069] In the vane pump 100 , the main body side panel 30 further includes a suction port 33 for introducing the working fluid into the pump chamber 6 , and a communication groove 37 for connecting the low pressure groove 34 b and the suction port 33 .
[0070] In this structure, since the low-pressure groove 34 b and the suction port 33 are connected by the communication groove 37 , the low-pressure working fluid can be introduced into the low-pressure groove 34 b .
[0071] In addition, in the vane pump 100 , the communication groove 37 is provided so as to be offset from the direction in which the slit 2 s extends.
[0072] In the vane pump 100 , the slits 2 s are provided so as to extend radially in the radial direction of the rotor 2 , and the communication grooves 37 are provided so as to extend linearly while being offset from the radial direction of the rotor 2 .
[0073] In the above-described structure, the communicating groove 37 can be made not to hinder the sliding of the blade 3 in the slit 2s.
[0074] In addition, in the vane pump 100, the inner peripheral cam surface 4a has: a first curved surface 141, which is arranged in the suction area 42a, 42c, and the radial dimension between the first curved surface 141 and the rotor 2 increases by a certain amount along the rotation direction of the rotor 2; a second curved surface 142, which is continuous with the first curved surface 141 and is arranged in the suction area 42a, 42c on the front side of the rotation direction of the rotor 2 compared with the first curved surface 141, and the amount of change in the radial dimension between the second curved surface 142 and the rotor 2 decreases along the rotation direction of the rotor 2, and 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 as the rotor 2 rotates.
[0075] In this structure, the change amount of the radial dimension between the second curved surface 142 and the rotor 2 becomes smaller along the rotation direction of the rotor 2. Therefore, when the blade 3 is in sliding contact with the second curved surface 142, the change in the protrusion amount of the blade 3 caused by the rotation of the rotor 2 is small. As a result, the low-pressure groove 34b is connected to the back pressure chamber 5 from the area where the change in the protrusion amount of the blade 3 caused by the rotation of the rotor 2 begins to decrease, and guides the low-pressure working fluid to the back pressure chamber 5. Therefore, through the low-pressure groove 34b, the friction force generated between the blade 3 and the inner peripheral cam surface 4a can be efficiently reduced in the area where the change in the protrusion amount of the blade 3 is small.
[0076] 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.
[0077] This application claims priority based on Japanese Patent Application No. 2022-101644 filed with the Japan Patent Office on June 24, 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 side member arranged to contact a 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 side member has a back pressure groove communicating with the back pressure chamber in a suction region where the volume of the pump chamber expands. The back pressure tank has: a first groove that guides the working fluid to the back pressure chamber; a second groove that guides the working fluid to the back pressure chamber that is located forward of the back pressure chamber in the rotation direction of the rotor relative to the back pressure chamber to which the working fluid is guided by the first groove, and guides the working fluid having a lower pressure than the working fluid guided by the first groove to the back pressure chamber; The working fluid is selectively introduced into the back pressure chamber from the first groove or the second groove as the rotor rotates.
2. The vane pump according to claim 1, wherein: The second groove is provided to be separated from the first groove in a manner not to communicate with the first groove.
3. The vane pump according to claim 2, wherein: The side member further includes a suction port for introducing the working fluid into the pump chamber, and a communication groove for connecting the second groove with the suction port.
4. The vane pump according to claim 3, wherein: The communicating groove is disposed to be offset from a direction in which the slit extends.
5. The vane pump according to claim 4, wherein: The slits are arranged to extend radially along the radial direction of the rotor. The communication groove is provided to be offset from the radial direction of the rotor and to extend linearly.
6. The vane pump according to claim 2, wherein: The inner circumferential cam surface has: A first curved surface, which is disposed in the suction region and has a radial dimension between the first curved surface and the rotor that increases by a certain amount along the rotation direction of the rotor; a second curved surface which is continuous with the first curved surface and is provided in the suction region on the front side of the first curved surface in the rotation direction of the rotor, and wherein a change in a radial dimension between the second curved surface and the rotor decreases along the rotation direction of the rotor, 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.