JP2009275537A - Variable displacement vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement vane pump capable of preventing cavitation from occurring in high speed rotation of a rotor. <P>SOLUTION: The variable displacement vane pump is equipped with a return passage 106 for returning a part of a hydraulic oil discharged from the variable displacement vane pump 100 to an intake passage 108, a return throttle 105 which is interposed in the return passage 106 and throttles the flow of the hydraulic oil, and a supercharging means 104 which sucks the hydraulic oil flowing in the intake passage 108 by a negative pressure generated by the hydraulic oil accelerated through the return throttle 105 to supply it between vanes 3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a variable displacement vane pump used as a hydraulic pressure supply source in hydraulic equipment.

  Conventionally, a variable displacement vane pump in which the flow rate of hydraulic fluid supplied to hydraulic equipment is adjusted by changing the volume of hydraulic fluid discharged through the vane, and the volume of hydraulic fluid discharged through the vane is constant. There are fixed displacement vane pumps in which the flow rate of hydraulic oil supplied to hydraulic equipment is not adjusted.

  In the fixed capacity type vane pump, since the time for sucking the hydraulic oil is shortened as the rotational speed of the rotor increases, the suction flow rate sucked through the vane is insufficient, and cavitation may occur.

  In response to this, the fixed displacement vane pump disclosed in Patent Document 1 returns a part of the hydraulic oil discharged from the vane pump to the suction passage of the vane pump in accordance with the discharge flow rate of the vane pump to prevent cavitation. It is like that.

Further, the fixed displacement vane pump disclosed in Patent Document 2 returns a part of the hydraulic oil discharged from the vane pump to the suction passage, and the suction passage is formed by the negative pressure generated by the hydraulic oil accelerated through the throttle. The flowing hydraulic oil is sucked and sent between the vanes to prevent cavitation.
JP 2007-231871 A JP 2007-278258 A

  On the other hand, since the variable displacement vane pump is adjusted so that the discharge flow rate becomes a predetermined value according to the rotational speed of the rotor, the suction flow rate does not increase in proportion to the rotational speed like the fixed displacement vane pump. The cavitation was considered unlikely to occur.

  However, in a variable displacement vane pump that is a hydraulic source for hydraulic equipment that requires a large supply flow rate of hydraulic oil, cavitation may occur due to insufficient suction of hydraulic oil into the pump chamber during high-speed rotation of the rotor. there were.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a variable displacement vane pump that can suppress the occurrence of cavitation during high-speed rotation of a rotor.

  The present invention sucks the working fluid from the suction passage by a plurality of vanes protruding from the rotating rotor, discharges the working fluid to the discharge passage, and changes the volume of the working fluid discharged through the vane to change the fluid from the discharge passage. A variable displacement vane pump for adjusting the flow rate of the working fluid supplied to the pressure device, wherein a part of the working fluid discharged from the vane pump is returned to the suction passage, and the working fluid is disposed in the return passage. A return throttle for restricting the flow, and a supercharging means for sucking the working fluid flowing through the suction passage by the negative pressure generated by the working fluid accelerated through the return throttle and sending it between the vanes. It was supposed to be.

  According to the present invention, when the rotor rotates at high speed, the vane pump sucks the working fluid flowing through the suction passage by the negative pressure generated by the working fluid accelerated through the return throttle that constitutes the supercharging means, and passes the suction to the suction port. By supplying, it is possible to suppress an increase in the negative pressure in the pump chamber, and it is possible to prevent the occurrence of noise, vibration and insufficient discharge due to cavitation.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing a section parallel to the axial direction of the drive shaft 1 in the variable displacement vane pump 100, and FIG. 2 is a transverse section showing a section orthogonal to the axial direction of the drive shaft 1 in the variable displacement vane pump 100. FIG.

  A variable displacement vane pump (hereinafter simply referred to as “vane pump”) 100 accommodates a plurality of vanes 3 provided so as to be capable of reciprocating in the radial direction with respect to the rotor 2, and the rotor 2. Along with this, a cam ring 4 that slides on the cam surface on the inner periphery and is eccentric with respect to the center of the rotor 2 is provided.

  The pump body 10 is formed with a pump housing recess 10 a for housing the cam ring 4. A side plate 6 that contacts one side of the rotor 2 and the cam ring 4 is disposed at the bottom of the pump housing recess 10a. The opening of the pump housing recess 10 a is sealed by a pump cover 5 that contacts the rotor 2 and the other side of the cam ring 4.

  As described above, the pump cover 5 and the side plate 6 are arranged with the both sides of the rotor 2 and the cam ring 4 sandwiched therebetween. Thereby, a pump chamber 7 partitioned by the vanes 3 is defined between the rotor 2 and the cam ring 4.

  The cam ring 4 is an annular member, and a suction region that expands the volume of the pump chamber 7 partitioned by the vanes 3 as the rotor 2 rotates, and a pump chamber 7 partitioned by the vanes 3 are provided. A discharge region for shrinking the volume is provided. The pump chamber 7 sucks the working oil (working fluid) in the suction area and discharges the working oil in the discharge area. In FIG. 2, the rotor 2 rotates counterclockwise as indicated by an arrow, and a suction area is above the center line of the cam ring 4 and a discharge area is below the center line of the cam ring 4.

  In the pump cover 5, a suction port 15 that opens in an arc shape in the suction region is formed, and hydraulic oil is sucked into the pump chamber 7 from the suction port 15.

  The pump cover 5 is formed with an inlet 52 communicating with the suction port 15, and hydraulic oil in the tank 103 (see FIG. 4) is guided to the suction port 15 through a pipe 51 connected to the inlet 52. . A suction passage 108 (see FIG. 4) that guides the hydraulic oil in the tank 103 to the suction port 15 is configured by the pipe 51, the inlet 52, and the like.

  In the side plate 6, a discharge port 16 that opens in an arc shape in the discharge region is formed, and hydraulic oil is discharged from the pump chamber 7 to the discharge port 16.

  The pump body 10 is formed with a high-pressure chamber 18 that communicates with the discharge port 16 and a delivery port 19 that communicates with the high-pressure chamber 18. Pressurized hydraulic fluid is connected to the pump body 10 via a pipe (not shown) connected to the delivery port 19. Is guided to a hydraulic device (fluid pressure device) 101 (see FIG. 4). A discharge passage 109 (see FIG. 4) that guides hydraulic oil discharged from the discharge port 16 to the hydraulic equipment 101 is configured by the high-pressure chamber 18, the delivery port 19, piping, and the like.

  As a variable displacement mechanism that changes the amount of eccentricity of the cam ring 4 with respect to the rotor 2, an annular adapter ring 11 is fitted in the pump housing recess 10 a of the pump body 10 so as to surround the cam ring 4. A support pin 13 is interposed therebetween. As the cam ring 4 swings around the support pin 13 inside the adapter ring 11, the amount of eccentricity of the cam ring 4 with respect to the rotor 2 changes, and the discharge capacity of the pump chamber 7 changes.

  A sealing material 14 is interposed between the adapter ring 11 and the cam ring 4, and the outer peripheral surface of the cam ring 4 is in sliding contact with the sealing material 14 when the cam ring 4 swings. A first fluid pressure chamber 31 and a second fluid pressure chamber 32 are defined by the support pin 13 and the seal material 14 between the outer peripheral surface of the cam ring 4 and the inner peripheral surface of the adapter ring 11. The cam ring 4 swings around the support pin 13 as a fulcrum by the pressure difference between the hydraulic fluid in the first fluid pressure chamber 31 and the second fluid pressure chamber 32.

  As a pressure control means for moving the cam ring 4, a flow rate detection orifice 28 is interposed in the discharge passage 109, and the first fluid pressure chamber 31 and the second fluid pressure chamber 32 are provided according to the differential pressure across the flow rate detection orifice 28. A control valve 21 for controlling the hydraulic oil pressure to be guided is provided.

  Hereinafter, the flow rate detection orifice 28 will be described.

  A bottomed cylindrical plug 46 is attached to the pump body 10, and a piston 45 is slidably inserted into the plug 46.

  Between the bottom of the piston 45 and the outer peripheral surface of the cam ring 4, a feedback pin 40 that passes through the adapter ring 11 and follows the swing of the cam ring 4 is interposed.

  A cam spring 41 is interposed between the plug 46 and the piston 45. The cam spring 41 biases the cam ring 4 in a direction in which the amount of eccentricity with respect to the rotor 2 increases.

  A flow rate detection orifice 28 is formed in the cylindrical portion of the plug 46 so that the opening area of the flow rate detection orifice 28 is determined by the position of the piston 45 with respect to the cylindrical portion of the plug 46. The opening area of the flow rate detection orifice 28 is maximized when the cam ring 4 is decentered to the left as shown in FIG. 2 and the amount of decentering relative to the rotor 2 is maximized. From this state, as the cam ring 4 moves to the right in FIG. 2, the opening area of the flow rate detection orifice 28 gradually decreases.

  A gap 43 is defined between the outer peripheral surface of the plug 46 and the pump body 10, and the gap 43 communicates with the high-pressure chamber 18 through a through hole (not shown).

  The plug inner chamber 42 defined inside the plug 46 communicates with the delivery port 19 via a gap 47 defined outside the adapter ring 11 and a through hole 48.

  Hereinafter, the control valve 21 will be described.

  The control valve 21 includes a spool 22 that is slidably inserted into the valve housing hole 29. The valve housing hole 29 is formed in the pump body 10 in a direction orthogonal to the axial direction of the drive shaft 1.

  The opening end of the valve accommodating hole 29 is sealed with a plug 23. A first spool chamber 24 is defined between one end (first land portion 22 a) of the spool 22 and the plug 23, and a first pressure guide passage 37 communicating with the high pressure chamber 18 is opened in the first spool chamber 24. Then, the pump discharge pressure upstream of the flow rate detection orifice 28 is guided.

  A second spool chamber 25 is defined between the other end (second land portion 22 b) of the spool 22 and the bottom portion of the valve accommodating hole 29, and the second spool chamber 25 is connected to the second outlet 19. The pressure passage 38 is opened, and the pump discharge pressure downstream of the flow rate detection orifice 28 is guided.

  A return spring (biasing member) 26 that urges the spool 22 in a direction to expand the volume of the second spool chamber 25 is accommodated in the second spool chamber 25.

  The spool 22 moves to the right in FIG. 2 against the urging force of the return spring 26 as the differential pressure across the flow rate detection orifice 28 increases, and the load due to the pressure of the hydraulic oil guided to the spool 22 It stops at a position where the urging force of the return spring 26 is balanced.

  The spool 22 has a first land portion 22a and a second land portion 22b that slide along the inner peripheral surface of the valve accommodating hole 29, and is annular between the first land portion 22a and the second land portion 22b. A groove 22c is formed.

  The valve housing hole 29 includes a first fluid pressure passage 33 that communicates with the first fluid pressure chamber 31, a second fluid pressure passage 34 that communicates with the second fluid pressure chamber 32, and a drain passage 35 that communicates with the suction passage 108. Each is connected.

  The first fluid pressure passage 33 and the second fluid pressure passage 34 are formed inside the pump body 10 and are formed through the adapter ring 11.

  Depending on the position of the spool 22, the first fluid pressure passage 33 is opened and closed by the first land portion 22a, and the second fluid pressure passage 34 is opened and closed via the notch 22f of the second land portion 22b. 31 and the hydraulic fluid in the second fluid pressure chamber 32 are supplied and discharged.

  In the initial position where the spool 22 is in contact with the plug 23 as shown in FIG. 2, the first fluid pressure passage 33 is closed by the first land portion 22 a of the spool 22, and the first fluid pressure chamber 31 and the high pressure chamber 18 are separated. The communication is blocked, and the communication with the drain passage 35 is established via a communication passage (not shown) formed in the first land portion 22a. In this initial position, the second fluid pressure passage 34 is closed by the second land portion 22 b of the spool 22.

  As the differential pressure across the flow rate detection orifice 28 led to both ends of the spool 22 increases, the spool 22 moves to the right in FIG. 33 is opened by the first land portion 22a, and the pump discharge pressure of the high pressure chamber 18 is guided to the first fluid pressure chamber 31 via the first pressure guiding passage 37, the first spool chamber 24, and the first fluid pressure passage 33. . In this position, the second fluid pressure passage 34 is opened through the notch 22f of the second land portion 22b, and the pressure in the second fluid pressure chamber 32 is passed through the second fluid pressure passage 34, the annular groove 22c, and the drain passage 35. And drained into the suction passage 108. The communication between the second fluid pressure passage 34 and the annular groove 22c is performed via a notch 22f formed in the second land portion 22b of the spool 22, and the second fluid pressure chamber 32 is connected to the second fluid pressure chamber 32 according to the amount of movement of the spool 22. The opening area of the drain passage 35 increases or decreases.

  The second fluid pressure chamber 32 communicates with the high pressure chamber 18 via the throttle passage 36, and the pump discharge pressure of the high pressure chamber 18 is always guided.

  Next, the operation of the vane pump 100 configured as described above will be described.

  When the power of the engine 102 is transmitted to the drive shaft 1 and the rotor 2 rotates, the pump chamber 7, which expands between the vanes 3 as the rotor 2 rotates, sucks hydraulic oil from the suction passage 108 through the suction port 15. Further, the pump chamber 7 in which the space between the vanes 3 contracts discharges hydraulic oil to the high pressure chamber 18 through the discharge port 16. The hydraulic oil discharged to the high pressure chamber 18 is supplied to the hydraulic equipment 101 through the discharge passage 109.

  When the hydraulic oil passes through the discharge passage 109, a pressure difference is generated before and after the flow rate detection orifice 28 interposed in the discharge passage 109, and the pressure before and after the second and second spool chambers 25 and 25 of the control valve 21 is generated. Each of 24 is guided. In the control valve 21, the spool 22 moves to a position where the load due to the pressure of the hydraulic oil guided to the second spool chamber 25 and the first spool chamber 24 and the urging force of the return spring 26 are balanced.

  When the rotational speed of the rotor 2 is lower than the predetermined value, the differential pressure across the flow rate detection orifice 28 is smaller than the predetermined value. Therefore, the spool 22 is in a position where one end abuts against the plug 23 by the urging force of the return spring 26. Retained. In this case, since the communication between the first fluid pressure chamber 31 and the high pressure chamber 18 is blocked by the spool 22 and the communication between the second fluid pressure chamber 32 and the drain passage is also blocked, the cam ring 4 Due to the pressure of the second fluid pressure chamber 32 and the urging force of the cam spring 41, the eccentric amount with respect to the rotor 2 is maximized.

  In this way, the vane pump 100 discharges the hydraulic oil with the maximum discharge capacity, and discharges a flow rate that is substantially proportional to the rotational speed of the rotor 2. Thereby, even when the rotational speed of the rotor 2 is low, it is possible to supply the hydraulic fluid with a sufficient flow rate to the hydraulic device 101.

  On the other hand, when the rotational speed of the rotor 2 is increased to a predetermined value or higher, the differential pressure across the flow rate detection orifice 28 increases to a predetermined value or higher, so that the spool 22 resists the urging force of the return spring 26. Moving. In this case, since the first fluid pressure chamber 31 communicates with the high pressure chamber 18 and the second fluid pressure chamber 32 communicates with the drain passage 35, the cam ring 4 is connected to the first fluid pressure chamber 31 and the second fluid pressure chamber. According to the pressure difference with the chamber 32, the eccentric amount with respect to the rotor 2 moves in a direction that decreases.

  In this way, the vane pump 100 is adjusted to a pump discharge capacity corresponding to the differential pressure across the flow rate detection orifice 28. As the amount of eccentricity of the cam ring decreases, the amount of eccentricity is transmitted to the feedback pin 40, and the piston 45 moves to the right in FIG. 2, so the opening area of the flow rate detection orifice 28 decreases. Therefore, the discharge flow rate of the vane pump 100 gradually decreases as the rotational speed of the rotor 2 increases to a predetermined value or more. As a result, the amount of hydraulic oil supplied to the hydraulic device 101 when the vehicle is running is moderately adjusted.

  FIG. 3 is a characteristic diagram showing the relationship between the rotational speed N of the rotor 2 and the discharge flow rate Q of the vane pump 100. In a state where the rotational speed N of the rotor 2 is lower than a predetermined value, the cam ring 4 is eccentric to the maximum with respect to the rotor 2 as shown in FIG. 2, and the discharge flow rate Q substantially proportional to the rotational speed of the rotor 2 increases. As the rotational speed N of the rotor 2 rises above a predetermined value, the eccentricity of the cam ring 4 with respect to the rotor 2 is reduced by the operation of the control valve 21 that responds to the differential pressure across the flow rate detection orifice 28, and the discharge flow rate Q Gradually decreases.

  In FIG. 3, Q2 is the maximum discharge flow rate of the vane pump 100, and Q1 is the maximum supply flow rate required by the hydraulic device 101. The discharge flow rate of the vane pump 100 is set so that the maximum discharge flow rate Q2 is larger than the maximum supply flow rate Q1 by a predetermined value (Q2-Q1). Accordingly, when the discharge flow rate Q of the vane pump 100 reaches the maximum discharge flow rate Q2 as the rotational speed N of the rotor 2 increases to a predetermined value or more, the hydraulic oil at the flow rate (Q2-Q1) is excessive. It is set as the structure discharged as a flow.

  FIG. 4 is a hydraulic circuit diagram in which the variable displacement vane pump 100 and the hydraulic equipment 101 are arranged.

  The hydraulic device 101 is a transmission mounted on a vehicle, for example, and is configured to switch a transmission gear ratio for transmitting the power of the engine 102 to wheels by an operating hydraulic pressure.

  The vane pump 100 used as a hydraulic pressure supply source of the hydraulic equipment 101 is supplied with hydraulic oil stored in the tank 103 through the suction passage 108, and pressurized hydraulic oil discharged from the hydraulic oil 101 passes through the discharge passage 109. To be supplied. The hydraulic oil discharged from the hydraulic device 101 is returned to the tank 103 through the discharge passage 107.

  A return passage 106 for returning a part of the pressurized hydraulic oil discharged from the vane pump 100 to the suction passage 108 is provided, and a return throttle 105 for reducing the flow of the hydraulic oil is provided in the return passage 106. The vane pump 100 is configured such that as the rotational speed N of the rotor 2 increases to a predetermined value or more, the hydraulic oil at a flow rate (Q2-Q1) discharged by the vane pump 100 as an excess flow is returned to the suction passage 108 through the return passage 106. And

  The return passage 106 communicates the discharge passage 109 and the suction passage 108. One end of the return passage 106 communicates with the discharge passage 109, the other end communicates with the suction passage 108, and part of the hydraulic oil flowing through the discharge passage 109 branches into the return passage 106 and flows into the suction passage 108. To do.

  A diversion valve 110 is interposed at a connection portion of the return passage 106 with respect to the discharge passage 109, and the diversion valve 110 is adjusted so that the opening area of the return passage 106 increases as the discharge flow rate of the vane pump 100 increases. The The diverter valve 110 includes a throttle 111 interposed in the discharge passage 109 and a spool (not shown) that responds to the differential pressure across the throttle 111, and the opening area of the return passage 106 with respect to the discharge passage 109 by the spool. Is adjusted.

  Hereinafter, the supercharging means 104 which sends hydraulic oil between the vanes 3 will be described.

  As shown in FIG. 1, the pump cover 5 is connected to the inlet 52 to which the pipe 51 of the suction passage 108 is connected, and extends coaxially with the inlet 52 so as to be orthogonal to the inlet port 15. And a return port 9 connected so as to be orthogonal to the supercharge hole 53, and a pipe (not shown) that defines a return passage 106 is connected to the return port 9.

  As shown in FIG. 2, the suction port 15 has an arc-shaped cross section concentric with the rotation center axis (drive shaft 1) of the rotor 11, and has a semi-cylindrical shape that guides hydraulic oil to the pump chamber 7 between the vanes 3. The flow path is defined.

  The inlet 52 constitutes the suction passage 108. The supercharging passage 53 extending coaxially with the inlet 52 defines a circular cross-sectional flow path extending in a direction perpendicular to the rotation center axis of the rotor 11 and is connected to the central portion of the semi-cylindrical suction port 15. To be formed. The flow passage cross-sectional area of the hydraulic oil extends from the supercharging passage 53 to the suction port 15. That is, the suction port 15 has an enlarged flow passage cross-sectional area with respect to a joining portion where the working oil that has passed through the return throttle 105 joins with the working oil that has passed through the supercharging passage 53.

  Thereby, the flow direction of the working oil from the supercharging hole 53 toward the suction port 15 is bent as indicated by an arrow in FIG. 1, and the flow velocity is reduced as the flow path cross-sectional area is expanded.

  The pump cover 5 is also formed with a drain passage 39 extending from the supercharging hole 53 to the end of the drive shaft 1.

  One end of the return passage 106 communicates with the return port 9 of the pump cover 5 through the return port 9, the other end is connected to the pump body 10, and a high pressure is supplied through a through hole (not shown) formed in the pump body 10. It communicates with the chamber 18.

  The return port 9 communicates with a connection portion between the supercharging through hole 53 and the suction port 15 through the through hole 8. The return port 9 and the through hole 8 extend substantially parallel to the rotation center axis of the rotor 11, are orthogonal to the supercharging hole 53, and are formed so as to extend coaxially with the suction port 15.

  The return throttle 105 is interposed in the return port 9 and is arranged so as to be orthogonal to the supercharging hole 53 and extend coaxially with respect to the suction port 15. The hydraulic fluid that flows into the suction passage 108 from the return passage 106 passes through the return throttle 105 to increase the flow velocity thereof, and flows straight into the suction port 15 as shown by an arrow in FIG. The hydraulic oil that has passed through the return throttle 105 accelerates and flows into the suction port 15, thereby generating a negative pressure at the opening of the supercharging hole 53, and operating oil from the supercharging hole 53 to the suction port 15. Is sucked and hydraulic oil is supercharged to the suction port 15.

  That is, the supercharging means 104 sucks the hydraulic oil flowing through the suction passage 108 by the pressure drop generated by the hydraulic oil accelerated through the return throttle 105 and is supercharged to the suction port 15. To do.

  As described above, in the vane pump 100, the hydraulic oil stored in the tank 103 is supplied through the suction passage 108, and the pressurized hydraulic oil discharged therefrom is supplied to the hydraulic equipment 101 through the discharge passage 109. As shown in FIG. 3, the variable displacement vane pump 100 is adjusted so that the discharge flow rate Q becomes a predetermined value according to the rotational speed N of the rotor 2. For this reason, conventionally, variable displacement vane pumps were considered unlikely to cause cavitation because the suction flow rate did not increase in proportion to the rotational speed unlike fixed displacement vane pumps.

  However, even in a variable displacement vane pump that is adjusted so that the discharge flow rate becomes a predetermined value, cavitation may occur due to insufficient suction of hydraulic oil into the pump chamber during high-speed rotation of the rotor.

  In response to this, in the variable displacement vane pump 100 of the present invention, when the rotor 2 rotates at a high speed, the hydraulic oil having a flow rate (Q2-Q1) discharged as a surplus flow set in advance is returned to the suction passage 108 through the return passage 106. The hydraulic oil is returned and accelerated through the return throttle 105 constituting the supercharging means 104, whereby the hydraulic oil flowing through the suction passage 108 is sucked and sent to the suction port 15. Due to this supercharging action, the vane pump 100 improves the suction performance of the hydraulic oil when the rotor 2 rotates at a high speed, suppresses the occurrence of cavitation in the pump chamber 7 and the like, and is free from noise and vibration due to cavitation and insufficient discharge flow rate. It can be prevented from occurring.

  As described above, in the present embodiment, the hydraulic oil is sucked from the suction passage 108 by the plurality of vanes 3 protruding from the rotating rotor 2 and is discharged to the discharge passage 109 and discharged through the vane 3. The variable displacement vane pump 100 adjusts the flow rate of hydraulic oil supplied from the discharge passage 109 to the hydraulic equipment 101 by changing the volume of the hydraulic oil to be supplied. Return passage 106, return throttle 105 interposed in the return passage 106 to restrict the flow of hydraulic oil, and operation to flow through the suction passage 108 by negative pressure generated by the hydraulic oil accelerated through the return throttle 105 A supercharging means 104 for sucking oil and feeding it between the vanes 3 is provided.

  Based on the above configuration, the vane pump 100 sucks the hydraulic oil flowing through the suction passage 108 by the negative pressure generated by the hydraulic oil accelerated through the return throttle 105 constituting the supercharging means 104 when the rotor 2 rotates at high speed. By supercharging the suction port 15, it is possible to suppress an increase in the negative pressure of the pump chamber 7 and to prevent noise and vibration caused by cavitation.

  In the present embodiment, the maximum discharge flow rate Q2 of the vane pump 100 is set larger by a predetermined value (Q2-Q1) than the maximum supply flow rate Q1 required by the hydraulic device 101, and as the rotational speed N of the rotor 2 increases. Thus, the hydraulic fluid having a flow rate (Q2-Q1) discharged from the vane pump 100 as an excess flow is returned to the suction passage 108 through the return passage 106.

  Based on the above configuration, in the vane pump 100, when the rotor 2 rotates at high speed, the hydraulic oil having a flow rate (Q2-Q1) discharged as a surplus flow set in advance is returned to the suction passage 108 through the return passage 106, and the supercharging means 104 The negative pressure in the pump chamber 7 is increased by sucking the hydraulic oil flowing through the suction passage 108 by the negative pressure generated by the hydraulic oil accelerated through the return throttle 105 that constitutes the pressure and supercharging the suction port 15. And the generation of noise and vibration due to cavitation is prevented.

  In the present embodiment, the return passage 106 communicates the discharge passage 109 and the suction passage 108, and a part of the hydraulic oil flowing through the discharge passage 109 branches to the return passage 106 and flows into the suction passage 108.

  Based on the above configuration, in the vane pump 100, when the rotor 2 rotates at a high speed, hydraulic oil having a flow rate (Q2-Q1) discharged as a surplus flow set in advance is returned to the suction passage 108 through the return passage 106.

  In the present embodiment, the flow dividing valve 110 is provided at the connection portion of the return passage 106 to the discharge passage 109, and the opening area of the return passage 106 increases as the discharge flow rate of the vane pump 100 is increased by the flow dividing valve 110. It was set as the structure adjusted so that it might become large.

  Based on the above configuration, the flow rate of the hydraulic oil that is diverted to the return passage 106 is adjusted by the diversion valve 110 according to the discharge flow rate of the vane pump 100.

In the present embodiment, as the supercharging means 104, the suction port 15 that guides the hydraulic oil between the vanes 3 in the suction region where the volume between the vanes 3 expands, and the hydraulic oil from the suction passage 108 is supplied to the suction port 15. A supercharging passage hole 53 for guiding, and a return port 9 in which a return throttle 105 is interposed;
The return port 9 communicates with the suction port 15 through the supercharging hole 53, and flows from the junction where the hydraulic oil that has passed through the return throttle 105 merges with the hydraulic oil that has passed through the supercharging hole 53 to the suction port 15. The road cross-sectional area is increased.

  Based on the above configuration, after the hydraulic oil that has passed through the return throttle 105 merged with the hydraulic oil that has passed through the supercharging hole 53, the hydraulic oil flows into the suction port 15 where the cross-sectional area of the flow path expands, A pressure drop is promoted, and hydraulic oil can be efficiently supercharged from the supercharging passage 53 to the suction port 15.

  In the present embodiment, the return throttle 105 is arranged so as to extend coaxially with the suction port 15.

  Based on the above configuration, the hydraulic oil accelerated through the return throttle 105 advances straight through the supercharging hole 53 and flows into the suction port 15, so that there is little loss due to flow path resistance and the operation from the return passage 106 is performed. It can be supercharged efficiently with oil.

  In the present embodiment, as the cam ring 4 moves rightward in FIG. 2 and the amount of eccentricity of the cam ring 4 with respect to the rotor 2 decreases, the opening area of the flow rate detection orifice 28 gradually decreases. The control valve 21 controls the hydraulic oil pressure guided to the first fluid pressure chamber 31 and the second fluid pressure chamber 32 in accordance with the differential pressure across the orifice 28, whereby the rotational speed of the rotor 2 increases to a predetermined value or more. Accordingly, the discharge flow rate of the vane pump 100 gradually decreases.

  Based on the above configuration, the amount of hydraulic oil supplied to the hydraulic device 101 is appropriately adjusted, and the occurrence of cavitation when the rotor 2 rotates at high speed can be suppressed.

  As another embodiment, the opening area of the flow rate detection orifice 28 in FIG. 2 may be kept constant.

  In this case, as shown in FIG. 5 which shows the relationship between the rotational speed N of the rotor 2 and the discharge flow rate Q of the vane pump 100, the discharge flow rate Q is substantially reduced as the rotational speed N of the rotor 2 increases to a predetermined value or more. When the discharge flow rate Q of the vane pump 100 reaches the maximum discharge flow rate Q2 while being kept constant, the hydraulic oil at the flow rate (Q2-Q1) is discharged as an excess flow.

  As another embodiment, the opening area of the flow rate detection orifice 28 in FIG. 2 may be electronically controlled by a controller via an actuator.

  In this case, the rotational speed N of the rotor 2 at which the discharge flow rate Q of the vane pump 100 reaches the maximum discharge flow rate Q2 is arbitrarily set so as to show the relationship between the rotational speed N of the rotor 2 and the discharge flow rate Q of the vane pump 100 in FIG. Then, the hydraulic fluid having a flow rate (Q2-Q1) is discharged as an excess flow in a predetermined operation region where cavitation may occur.

  Next, another embodiment shown in FIG. 7 will be described. In addition, the same code | symbol is attached | subjected to the same structure part as the said embodiment.

  FIG. 7 is a hydraulic circuit diagram in which the variable displacement vane pump 100 and the hydraulic equipment 101 are arranged.

  The return passage 116 communicates the discharge port of the hydraulic device 101 and the suction passage 108. One end of the return passage 116 communicates with a discharge port through which hydraulic oil is discharged from the hydraulic device 101, the other end communicates with the suction passage 108, and a part of the hydraulic oil discharged from the hydraulic device 101 passes through the return passage 116. The remaining hydraulic oil that flows into the suction passage 108 and is discharged from the hydraulic device 101 is returned to the tank 103 through the discharge passage 107.

  The return passage 116 is provided with a return throttle 105 for restricting the flow of hydraulic oil, and the hydraulic oil flowing through the suction passage 108 is sucked by the pressure drop generated by the hydraulic oil accelerated through the return throttle 105, and the suction port The hydraulic oil is supercharged to 15.

  In the present embodiment, the return passage 116 connects the discharge port of the hydraulic device 101 and the suction passage 108, and a part of the hydraulic oil discharged from the hydraulic device 101 flows into the suction passage 108 from the return passage 116. did.

  Based on the above configuration, the entire amount of pressurized hydraulic oil discharged from the vane pump 100 is supplied to the hydraulic equipment 101, so that torque loss of the vane pump 100 can be reduced and cavitation due to insufficient suction can be prevented.

  Note that a working fluid such as a water-soluble alternative liquid may be used instead of the oil as the working oil.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

The longitudinal cross-sectional view of the vane pump which shows embodiment of this invention. Similarly, a cross-sectional view of the vane pump. The characteristic view which similarly shows the relationship between the rotational speed N of a rotor, and the discharge flow rate Q of a vane pump. Similarly hydraulic circuit diagram. The characteristic view which shows the relationship between the rotational speed N of the rotor which shows other embodiment, and the discharge flow rate Q of a vane pump. The characteristic view which shows the relationship between the rotational speed N of the rotor which shows other embodiment, and the discharge flow rate Q of a vane pump. The hydraulic circuit diagram which shows other embodiment.

Explanation of symbols

2 Rotor 3 Vane 4 Cam ring 7 Pump chamber 9 Return port 15 Suction port 16 Discharge port 21 Control valve 22 Spool 28 Flow rate detection orifice 53 Supercharging passage 100 Variable displacement vane pump 101 Hydraulic equipment (hydraulic pressure equipment)
103 Tank 104 Supercharging Means 105 Return Restriction 106 Return Passage 107 Discharge Passage 108 Suction Passage 109 109 Discharge Passage 110 Branch Flow Valve 111 Restriction 116 Return Passage

Claims (7)

The working fluid is sucked in from the suction passage by the plurality of vanes protruding from the rotating rotor, and the working fluid is discharged into the discharge passage,
A variable displacement vane pump that adjusts the flow rate of the working fluid supplied from the discharge passage to the fluid pressure device by changing the volume of the working fluid discharged through the vane;
A return passage for returning a part of the working fluid discharged from the vane pump to the suction passage;
A return throttle interposed in the return passage to restrict the flow of the working fluid;
A variable displacement vane pump comprising: a supercharging means that sucks the working fluid flowing through the suction passage by negative pressure generated by the working fluid accelerated through the return throttle and sends it between the vanes. Set the maximum discharge flow rate of the vane pump by a predetermined value larger than the maximum supply flow rate required by the fluid pressure device,
2. The configuration according to claim 1, wherein a working fluid having a flow rate discharged by the vane pump as an excess flow as the rotational speed N of the rotor increases is returned to the suction passage through the return passage. Variable displacement vane pump. The return passage communicates the discharge passage and the suction passage,
3. The variable displacement vane pump according to claim 1, wherein a part of the working fluid flowing through the discharge passage branches into the return passage and flows into the suction passage. A diversion valve interposed in a connection portion of the return passage with respect to the discharge passage,
4. The variable according to claim 1, wherein the diverter valve is adjusted so that the opening area of the return passage increases as the discharge flow rate of the vane pump increases. 5. Capacity type vane pump. As the supercharging means, a suction port for guiding the working fluid between the vanes in a suction region where the volume between the vanes expands;
A supercharging passage for guiding the working fluid from the suction passage to the suction port;
A return port in which the return aperture is interposed,
The return port communicates with the suction port through the supercharging hole.
5. The flow passage cross-sectional area is increased from the merging portion where the hydraulic oil that has passed through the return throttle merges with the hydraulic oil that has passed through the supercharging hole to the suction port. 6. The variable displacement vane pump according to any one of the above.   6. The variable displacement vane pump according to claim 5, wherein the return throttle is arranged to extend coaxially with the suction port. The return passage communicates the outlet of the fluid pressure device and the suction passage,
2. The variable displacement vane pump according to claim 1, wherein a part of the working fluid discharged from the fluid pressure device flows into the suction passage from the return passage.

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