JP2011132868A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vane pump capable of inhibiting the generation of a turbulent flow or the like between a working fluid in an intake passage and a return flow in which a part of the working fluid discharged from a pump chamber is returned selectively. <P>SOLUTION: The vane pump includes vanes 3 supported for reciprocation in the radial direction by a rotor 2 connected with a drive shaft 1, a cam ring 4 having an inner circumference on which the vanes 3 slide accompanied by the rotation of the rotor 2, the intake passage 11 for introducing the working fluid sucked in the pump chamber 7 defined by the cam ring 4 and the vanes 3, and a supply passage for supplying the working fluid discharged from the pump chamber 7 to fluid pressure equipment. The intake passage 11 is formed along the outer circumference of the cam ring 4 and includes an annular passage 9 introducing the working fluid to the pump chamber 7, and a return passage 20 is connected with the annular passage 9 and formed so that the return flow is joined with the working fluid flowing in the annular passage 9 along its flow. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vane pump used as a fluid pressure supply source of a fluid pressure device.

  In the vane pump, a plurality of vanes held by a rotor that rotates with the rotation of a drive shaft rotate while sliding on the inner periphery of a cam ring having a suction region and a discharge region. The working fluid is sucked into and discharged from the pump chamber.

  Patent Document 1 discloses a so-called two-stage variable displacement vane pump, a so-called two-stage variable displacement vane pump capable of switching the discharge amount of the working fluid.

  In the two-stage variable displacement vane pump, the working fluid discharged from one of the two discharge areas facing each other across the drive shaft is constantly supplied into the discharge oil passage. Then, it is possible to switch between supplying the working fluid discharged from the other discharge region into the discharge oil passage or returning to the suction side. Thereby, the discharge volume of a working fluid can be switched in two steps.

Japanese Patent No. 3573242

  By the way, in the two-stage variable displacement vane pump of Patent Document 1, the working fluid recirculated to the suction side flows so as to directly flow into the pump chamber from a return passage formed facing the suction passage. Since this return flow is a working fluid discharged from the pump and has a high pressure, when it is supplied again to the pump chamber, it generates turbulence that becomes a resistance that prevents the flow when it merges with the working fluid from the suction passage. In addition, the suction efficiency of the pump may be reduced.

  Then, an object of this invention is to provide the vane pump which can suppress generation | occurrence | production of a turbulent flow etc. when a return flow merges with the working fluid from a suction passage.

  The present invention includes a rotor coupled to a drive shaft, a vane supported by the rotor so as to be capable of reciprocating in a radial direction, a cam ring in which the vane slides on an inner periphery as the rotor rotates, A pump chamber defined by a cam ring and the vane, a suction passage for guiding a working fluid to the pump chamber, a supply passage for supplying the working fluid discharged from the pump chamber to a fluid pressure device, A return passage through which a return flow for selectively returning a part of the working fluid flowing through the supply passage to the suction passage flows, wherein the suction passage is formed along the outer periphery of the cam ring. An annular passage for guiding the working fluid to the pump chamber; the return passage is connected to the annular passage, and the return flow joins along the flow of the working fluid flowing through the annular passage Characterized in that it is formed so that.

  In the present invention, the return flow in which part of the working fluid discharged from the pump chamber and supplied from the supply passage to the fluid pressure device is selectively returned to the suction passage is returned through the return passage. The return passage is formed such that the return flow merges from the opening on the outer periphery of the annular passage along the flow of the working fluid in the annular passage. Therefore, generation | occurrence | production of the turbulent flow etc. when a return flow merges with the working fluid from a suction passage can be suppressed.

It is the figure which showed the front view of the vane pump which concerns on embodiment of this invention in the state which removed the pump cover.

  Hereinafter, a vane pump 100 according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, hydraulic pressure is used as the fluid pressure.

  The vane pump 100 is used as a hydraulic pressure supply source for hydraulic equipment (not shown) mounted on the vehicle, such as a power steering device or an automatic transmission. These hydraulic devices correspond to fluid pressure devices.

  The vane pump 100 includes a rotor 2 that is connected to the drive shaft 1 and rotates, a plurality of vanes 3 that can be reciprocated in the radial direction with respect to the rotor 2, and the rotor 2. A cam ring 4 on which the tip of the vane 3 slides is provided on the inner circumferential cam surface 4a.

  The vane pump 100 is configured such that the power of an engine (not shown) as a power source is transmitted to the end of the drive shaft 1 and the rotor 2 rotates. The rotor 2 rotates counterclockwise as viewed in FIG.

  The drive shaft 1 is rotatably supported by the pump body 10 via a bearing (not shown) inserted into the pump body 10. One end of the drive shaft 1 protrudes to the outside of the pump body 10. A pulley (not shown) to which engine power is transmitted via a belt is connected to the projecting portion of the drive shaft 1 projecting from the pump body 10.

  In the rotor 2, slits 2a having openings on the outer peripheral surface are radially formed at predetermined intervals, and the vanes 3 are slidably inserted into the slits 2a.

  The cam ring 4 is an annular member whose inner peripheral cam surface 4a has a substantially elliptical shape. A plurality of pump chambers 7 partitioned by the adjacent vanes 3 are defined on the inner periphery of the cam ring 4. In the present embodiment, twelve pump chambers 7 are defined by twelve vanes 3.

  The cam ring 4 includes two suction regions 4d and 4e that expand the volume of the pump chamber 7 at left and right symmetrical positions, and two discharge regions 4b and 4c that contract the volume of the pump chamber 7 at upper and lower symmetrical positions.

  The cam ring 4 is housed in a pump housing recess 10 a formed in the pump body 10. The pump accommodating recess 10a is formed to be open to accommodate components such as the cam ring 4 and the rotor 2.

  A pump cover (not shown) for closing the pump housing recess 10a is disposed in contact with one side surface (front side in FIG. 1) of the cam ring 4 and the rotor 2, and is disposed on the other side surface (back side in FIG. 1). Is arranged in contact with a side plate (not shown) in which a flow path for hydraulic oil discharged from the pump chamber 7 is formed. As described above, the pump cover and the side plate are arranged with both side surfaces of the rotor 2 and the cam ring 4 being sandwiched, and seal the pump chamber 7.

  The relative positions of the side plate, the cam ring 4, and the pump cover are fixed by positioning pins (not shown) that are inserted, and their rotations are suppressed. The pump cover is fixed by being fastened to the pump body 10 with screws (not shown) as fastening means.

  In the pump cover, suction recesses (not shown) are formed in each of the suction areas 4d and 4e for sucking hydraulic oil from the outer periphery via the side surface of the cam ring 4. The suction recess is formed in a concave shape on the side surface of the pump cover that contacts the cam ring 4. Therefore, a channel for supplying hydraulic oil into the pump chamber 7 is formed between the cam ring 4 and the pump cover.

  In order to guide the hydraulic oil supplied from the outside to the pump chamber 7, the pump body 10 has a suction port 8 opened to the outside and a hydraulic oil sucked from the suction port 8 for guiding the hydraulic oil to the suction areas 4 d and 4 e. An annular passage 9 is formed. The suction port 8 and the annular passage 9 form a part of a suction passage 11 for guiding hydraulic oil sucked into the pump chamber 7 from a tank (not shown).

  The annular passage 9 is defined by the outer periphery of the cam ring 4 and the inner periphery of the pump body 10. The annular passage 9 is formed so as to communicate the suction port 8 located substantially in the center with the two suction recesses of the pump cover. The annular passage 9 branches from the suction port 8 to the left and right, and is formed so as to surround the cam ring 4 over a substantially half circumference along the outer periphery of the cam ring 4. The annular passage 9 is connected to the suction regions 4d and 4e via suction recesses at both ends.

  At both ends of the annular passage 9, guide walls 9 a for changing the direction of the hydraulic oil flowing through the annular passage 9 and guiding it toward the suction recess are formed. The direction of the hydraulic oil flowing in the circumferential direction along the outer periphery of the cam ring 4 is changed by the guide wall 9a so as to flow in the radial direction toward the suction recess.

  As described above, the hydraulic oil supplied from the suction passage 11 flows from the suction port 8, branches into two, and flows through the annular passage 9 along the outer periphery of the cam ring 4. The hydraulic oil is guided to the two suction recesses along the guide wall 9a of the annular passage 9, and is supplied to the pump chamber 7 in the suction areas 4d and 4e.

  In the side plate, two discharge ports (not shown) through which hydraulic oil discharged from the pump chamber 7 is guided are formed so as to open corresponding to the discharge regions 4b and 4c of the cam ring 4.

  The pump body 10 has a discharge passage (not shown) for supplying hydraulic oil from the pump chamber 7 discharged in the discharge areas 4b and 4c to an external hydraulic device so as to communicate the two discharge ports. Is done. The discharge port and the discharge passage form part of a supply passage (not shown) for supplying hydraulic oil discharged from the pump chamber 7 to the hydraulic equipment.

  Each pump chamber 7 sucks hydraulic fluid from the suction passage 11 into the pump chamber 7 in the suction regions 4 d and 4 e of the cam ring 4 and rotates from the pump chamber 7 in the discharge regions 4 b and 4 c of the cam ring 4 as the rotor 2 rotates. Is discharged. The discharged hydraulic oil is supplied to the hydraulic equipment via the discharge port and the discharge passage, respectively. Thus, each pump chamber 7 supplies and discharges hydraulic oil by expansion and contraction accompanying the rotation of the rotor 2.

  The pump body 10 is formed with a return passage 20 for selectively returning a part of the hydraulic oil supplied from the supply passage to the hydraulic equipment as a return flow to the suction passage 11. A part of the hydraulic oil can be returned to the return passage 20 by switching a switching device such as a switching valve (not shown) provided downstream of the vane pump 100.

  The return passage 20 is a passage for returning a part of the hydraulic oil discharged from the pump chamber 7 to the annular passage 9 in the discharge regions 4 b and 4 c of the vane pump 100. The return passage 20 is formed in two places so that the opening 23 faces the respective suction recesses located at both ends of the annular passage 9, that is, the opening 23 faces the suction regions 4d and 4e, respectively. . The return flow recirculated from the return passage 20 merges with the hydraulic oil sucked from the suction port 8 and flows through the annular passage 9 and is guided to the pump chamber 7 from the suction recess. The return passage 20 is formed at two locations so that there is no difference in the pressure of the hydraulic oil in the two suction areas 4d and 4e, but the pressure of the hydraulic oil in the two suction areas 4d and 4e is equal. If there is, it does not have to be two places.

  The return passage 20 is formed so as to be parallel to the drive shaft 1 and the straight passage 21 perpendicularly intersecting the straight passage 21 and connected to the annular passage 9. And a return port 22 for joining the outer peripheral side of the annular passage 9.

  The straight passage 21 is a passage for returning the hydraulic oil discharged from the pump chamber 7 toward the suction passage 11 in the discharge region 4c. The hydraulic oil is sucked into the pump chamber 7 from the pump cover side (front side in FIG. 1) and discharged to the side plate side (back side in FIG. 1). Contrary to the flow, the straight passage 21 is linearly formed in parallel with the drive shaft 1 in order to guide hydraulic oil from the side plate side to the pump cover side, that is, from the discharge side to the suction side. By forming the straight passage 21 linearly, the return flow can be guided from the discharge side to the suction side with the shortest distance.

  The return port 22 is formed so as to be connected to the annular passage 9 from the tangential direction. The return port 22 is disposed on the same plane as the annular passage 9. When they are not arranged on the same plane, the return flow is obliquely merged with the hydraulic oil flowing through the annular passage 9 by an amount corresponding to the relative angle. However, when arranged on the same plane, the return flow is generated in the hydraulic oil flowing through the annular passage 9. It becomes easier to join.

  The return port 22 includes an opening 23 that opens into the annular passage 9. The opening 23 is formed in the outer periphery of the annular passage 9 so as to join the hydraulic oil along the flow of the hydraulic oil flowing through the annular passage 9. That is, the return port 22 is connected to the annular passage 9 through the opening 23.

  The hydraulic oil sucked from the suction port 8 flows downward through the annular passage 9 toward the suction regions 4d and 4e as viewed in FIG. Therefore, the return port 22 is formed so as to be obliquely connected from the tangential direction to the outer periphery of the annular passage 9 in the downward direction as viewed in FIG. Since the return port 22 is formed in a cylindrical shape, the opening 23 of the return port 22 is formed in an elliptical shape whose major axis is positioned in the direction in which the hydraulic oil flows.

  The return port 22 may be formed so as to have an acute angle with the annular passage 9 in addition to being connected to the annular passage 9 from the tangential direction. Thereby, it is possible to join the return flow along the hydraulic oil flowing through the annular passage 9.

  The return port 22 is formed so that hydraulic fluid flows from the tangential direction on the outer peripheral side of the annular passage 9 toward the guide walls 9 a formed at both ends of the annular passage 9. Therefore, the hydraulic oil that merges from the return port 22 does not flow directly into the pump chamber 7, but merges with the hydraulic oil that flows through the annular passage 9 and then flows into the pump chamber 7.

  The inner diameter of the return port 22 is formed smaller than the inner diameter of the annular passage 9. Thereby, when flowing into the annular passage 9 from the return port 22, the flow path is enlarged, and the flow velocity of the return flow is reduced. The pressure of the return flow increases as the flow velocity decreases, and the hydraulic oil that is sucked from the suction port 8 and flows through the annular passage 9 flows so as to be pushed into the pump chamber 7 by the pressure of the return flow. Therefore, the charge performance of the hydraulic fluid supplied from the suction recess to the pump chamber 7 is improved.

  Below, operation | movement of the vane pump 100 is demonstrated.

  First, the operation state of the vane pump 100 in which all of the hydraulic oil discharged from the pump chamber 7 in both the discharge regions 4b and 4c is supplied to the hydraulic equipment will be described.

  The rotor 2 is rotated by the rotation of the drive shaft 1, and a plurality of vanes 3 slidably inserted into the slits 2 a of the rotor 2 come in and out of the slits 2 a and are cam surfaces 4 a that are the inner periphery of the cam ring 4. Slide.

  When the pump chamber 7 partitioned by the adjacent vanes 3 reaches the suction areas 4d and 4e of the cam ring 4, the volume of the pump chamber 7 gradually expands, and the pump chamber 7 whose internal pressure is reduced is the suction port. Intake hydraulic fluid from 8.

  When the pump chamber 7 reaches the discharge areas 4b and 4c of the cam ring 4, the volume of the pump chamber 7 gradually contracts, and the pump chamber 7 whose internal pressure has increased operates via the discharge port and the discharge passage. Discharge the oil. The discharged hydraulic oil is supplied to the hydraulic equipment through the supply passage.

  Next, an operation state of the vane pump 100 in which part of the hydraulic oil discharged from the pump chamber 7 in the discharge regions 4b and 4c is guided to the return passage 20 will be described.

  A part of the hydraulic oil discharged from the pump chamber 7 in the discharge regions 4b and 4c is guided to the return passage 20 which is communicated by switching the switching valve. Therefore, the flow rate of the hydraulic oil supplied to the hydraulic equipment is reduced as compared with the case where the hydraulic oil discharged from the pump chamber 7 is supplied to the hydraulic equipment in both the discharge areas 4b and 4c.

  Part of the hydraulic oil discharged from the pump chamber 7 in the discharge regions 4b and 4c flows through the straight passage 21 and is guided from the discharge side to the suction side, and is returned to the annular passage 9 from the opening 23 of the return port 22. The

  Since the return port 22 is connected from the tangential direction of the outer wall of the annular passage 9, the hydraulic oil flowing from the return port 22 merges with the hydraulic oil flowing through the annular passage 9 without generating turbulence or the like. Is possible.

  Further, since the return port 22 is formed so that the hydraulic oil flows in toward the guide walls 9 a formed at both ends of the annular passage 9, the hydraulic oil flowing in from the return port 22 directly enters the pump chamber 7. Inflow can be prevented.

  From the return passage 20, high-pressure hydraulic oil discharged from the pump chamber 7 is recirculated in the discharge region 4b. Therefore, the hydraulic fluid that joins from the return passage 20 has a higher pressure than the hydraulic fluid that is sucked from the suction port 8 and flows through the suction passage 11.

  Further, the hydraulic oil flows into the annular passage 9 formed with an inner diameter larger than the diameter of the return port 22. Since the flow path is enlarged when it flows into the annular passage 9 from the return port 22, the flow velocity of the return flow decreases. The return flow increases in pressure as the flow velocity decreases, and the hydraulic oil flowing through the annular passage 9 flows so as to be pushed into the pump chamber 7 by the pressure. Therefore, the charge performance of the hydraulic fluid supplied from the suction recess to the pump chamber 7 is improved.

  According to the above embodiment, the following effects are obtained.

  The return flow in which the hydraulic oil discharged from the pump chamber 7 is recirculated to the suction passage 11 is recirculated through the return passage 20 formed so as to be connected and opened from the tangential direction of the outer wall of the annular passage 9. Therefore, since the hydraulic oil flowing in from the return port 22 merges along the flow of the hydraulic oil flowing through the annular passage 9, the occurrence of turbulence can be prevented.

  Therefore, even if the return flow merges with the hydraulic oil flowing through the suction passage 11, it is possible to prevent turbulent flow or the like from occurring in the hydraulic oil supplied to the pump chamber 7, and the pump suction efficiency can be increased.

  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.

  For example, in a two-stage variable displacement vane pump, hydraulic oil discharged from the pump chamber 7 in one discharge region 4b is always supplied to the hydraulic device, and hydraulic oil discharged from the pump chamber in the other discharge region 4c is supplied to the hydraulic device. It is also possible to adopt a configuration that can be switched by a switching valve to supply to the return passage 20 or to return to the return passage 20.

  The vane pump according to the present invention can be applied to a fluid pressure supply source such as a power steering device or a transmission for a vehicle.

100 Vane Pump 2 Rotor 3 Vane 4 Cam Ring 4b Discharge Area 4c Discharge Area 7 Pump Chamber 9 Annular Passage 10 Pump Body 11 Suction Passage 20 Return Passage 21 Linear Passage 22 Return Port 23 Opening

Claims (7)

A rotor coupled to the drive shaft;
A vane supported by the rotor so as to be capable of reciprocating in a radial direction;
A cam ring in which the vane slides on the inner periphery along with the rotation of the rotor;
A pump chamber defined by the cam ring and the vane;
A suction passage for guiding the working fluid to the pump chamber;
A supply passage for supplying hydraulic fluid discharged from the pump chamber to a fluid pressure device;
A return passage through which a return flow for selectively returning a part of the working fluid flowing through the supply passage to the suction passage flows,
The suction passage includes an annular passage that is formed along the outer periphery of the cam ring and guides the working fluid to the pump chamber.
The return passage is connected to the annular passage, and is formed so that the return flow merges along the flow of the working fluid flowing through the annular passage.   The vane pump according to claim 1, wherein the return passage is connected so that an angle with the suction passage is an acute angle.   The vane pump according to claim 2, wherein the return passage is formed to be connected to the annular passage from a tangential direction.   4. The vane pump according to claim 1, wherein an inner diameter of the return passage is smaller than an inner diameter of the annular passage. A pump body in which the cam ring is housed;
The vane pump according to any one of claims 1 to 4, wherein the annular passage is defined by an inner periphery of the pump body and an outer periphery of the cam ring. The return passage includes a return port connected to the annular passage through the opening,
The vane pump according to any one of claims 1 to 5, wherein the return port is disposed on the same plane as the annular passage. The cam ring is formed with two suction areas for sucking working fluid into the pump chamber,
The annular passage is connected to each of the two suction regions at both ends,
The vane pump according to any one of claims 1 to 6, wherein two return passages are formed to face each of the two suction regions.

Images