JP5345093B2 - Vane pump - Google Patents

Description

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

  As a conventional vane pump, in Patent Document 1, for the purpose of reducing driving torque, a plurality of pump chambers of a vane pump are divided into a main pump chamber that always supplies discharge oil and other sub pump chambers, and a discharge port of the sub pump chamber A switching control valve is provided in the middle of the discharge oil passage leading to the valve, and a return passage branched from the switching control valve communicates with the suction port of the main pump chamber to recirculate excess oil.

  Moreover, there exists a thing shown in FIG. 3 as this kind of vane pump. FIG. 3 (A) is a diagram illustrating a full discharge state in which hydraulic oil discharged from the main pump chamber 82 and the sub pump chamber 81 is supplied to the hydraulic device 87 as indicated by arrows in the drawing. ), The hydraulic oil discharged from the sub pump chamber 81 returns to the main pump chamber 82 through the return passage 86 as indicated by the arrow in the figure, and the hydraulic oil discharged only from the main pump chamber 82 is supplied to the hydraulic device 87. It is a figure which shows the half discharge state supplied.

Japanese Patent Laid-Open No. 10-266978

  In the vane pump shown in FIG. 3, since hydraulic oil is supplied to and discharged from the sub-pump chamber 81 even in a semi-discharge state, the consumed horsepower for driving the vane pump is wasted and the temperature of the hydraulic oil is increased. There was a point. Further, the self-priming performance is insufficient at the time of high rotation of the vane pump, and cavitation may occur.

  This invention is made | formed in view of said problem, and it aims at providing the vane pump which can reduce the horsepower consumed in a half discharge state.

  The present invention relates to a rotor that is rotationally driven, a plurality of vanes that project slidably from the rotor, a cam ring in which a tip end portion of the vane is in sliding contact with an inner peripheral cam surface, and a space between the cam ring and the vane. A main chamber and a sub region that perform suction and discharge of the working fluid as the rotor rotates, and perform suction and discharge of the working fluid in both the main region and the sub region. A vane pump having a switching valve that switches between a full discharge position and a half discharge position that sucks and discharges working fluid only in the main region, and the switching valve is configured so that the vane is drawn into the rotor at the half discharge position and the inner periphery of the cam ring. The pressure guided to the vanes in the sub-region is switched so as to be separated from the cam surface.

  According to the present invention, when the vane pump is switched to the semi-discharge state by the operation of the switching valve, the vane is separated from the cam ring in the sub region, so that the pump chamber communicates with the suction region and the discharge region, and the working fluid flows. Suction discharge is not performed. For this reason, in the semi-discharge state, the working fluid does not circulate unnecessarily through the sub-region, and the consumed horsepower for driving the rotor is reduced and the temperature rise of the working oil can be suppressed.

Sectional drawing which shows the full discharge state of the vane pump which shows embodiment of this invention. Sectional drawing which similarly shows the half discharge state of a vane pump. The block diagram of the vane pump which similarly shows a prior art example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  A vane pump 1 shown in FIGS. 1 and 2 is used as a hydraulic supply source for a hydraulic device mounted on a vehicle, for example, a power steering device or a transmission.

  However, the present invention is not limited to this, and the vane pump 1 may be used as a fluid pressure supply source for driving loads such as construction machines, work machines, other machines, and facilities.

  The vane pump 1 uses a working oil (oil) as a working fluid, but a working fluid such as a water-soluble alternative liquid may be used instead of the working oil.

  In the vane pump 1, the power of an engine (not shown) is transmitted to the end of the drive shaft 9, and the rotor 2 connected to the drive shaft 9 rotates. The rotor 2 rotates counterclockwise as indicated by an arrow in FIG.

  The vane pump 1 accommodates a plurality of vanes 3 provided so as to be capable of reciprocating in the radial direction with respect to the rotor 2, the rotor 2 and the vanes 3, and the tip of the vane 3 on the inner circumferential cam surface 4 a as the rotor 2 rotates. And a cam ring 4 on which the part slides.

  In the rotor 2, slits 2a having openings on the outer peripheral surface are radially formed at predetermined intervals, and the base end portion of the vane 3 is slidably inserted into the slits 2a.

  Back pressure chambers 11 to 14 to which the discharge pressure of the pump is guided are defined on the proximal end side of the slit 2a. The vane 3 is pressed by the pressure of the back pressure chambers 11 to 14 in the direction in which the base end portion is pulled out from the slit 2 a, and the tip end portion comes into contact with the inner peripheral cam surface 4 a of the cam ring 4. As a result, a plurality of pump chambers 7 are defined inside the cam ring 4 by the outer peripheral surface of the rotor 2, the inner peripheral cam surface 4 a of the cam ring, and the adjacent vanes 3.

  The cam ring 4 is an annular member whose inner circumferential cam surface 4a has a substantially oval shape. As the rotor 2 makes one revolution, each vane 3 sliding on the inner circumferential cam surface 4a reciprocates twice.

  The vane pump 1 has a main region in which the vane 3 reciprocates for the first time and a sub region in which the vane 3 reciprocates for the second time.

  The main region shrinks the volume of the pump chamber 7 and one suction region that expands the volume of the pump chamber 7 defined by the vanes 3 that slide on the inner circumferential cam surface 4 a as the rotor 2 rotates. It is constituted by one discharge area.

  Similarly, the sub-region includes one suction region that expands the volume of the pump chamber 7 defined by the vanes 3 that slide on the inner circumferential cam surface 4 a as the rotor 2 rotates, and the volume of the pump chamber 7. And one discharge region that contracts.

  The vane pump 1 has two suction regions and two discharge regions, but is not limited thereto, and may have a configuration having three or more suction regions and three or more discharge regions.

  The drive shaft 9 is rotatably supported by a pump body (not shown). The pump body is formed with a pump housing recess for housing the rotor 2, the cam ring 4, a side plate (not shown), and the like. A pump cover 50 is fastened to the pump body, and the pump housing recess is sealed by the pump cover 50.

  A main suction port 21 is opened in the suction area of the main area, and a sub suction port 23 is opened in the suction area of the sub area on the end surface of the pump cover 50 where the rotor 2 is in sliding contact.

  The main suction port 21 communicates with the valve accommodation hole 51 via the main suction passage 20, and communicates with the tank passage 45 via this valve accommodation hole 51. The tank passage 45 communicates with a tank (not shown) and supplies hydraulic oil from the tank to the main suction port 21.

  The sub suction port 23 communicates with the valve accommodating hole 51 via the sub suction passage 25 and selectively communicates with the tank passage 45 and a pump discharge passage (not shown) via a switching valve 60 described later.

  On the end surface of the pump cover 50 where the rotor 2 is in sliding contact, the main discharge port 22 opens in the discharge region of the main region, and the sub discharge port 24 opens in the discharge region of the sub region.

  The main discharge port 22 and the sub discharge port 24 communicate with each other, and both communicate with a pump discharge passage (not shown). The pressurized hydraulic fluid discharged from the main discharge port 22 and the sub discharge port 24 is supplied to the hydraulic equipment through the pump discharge passage.

  The main back pressure chambers 11 and 12 provided in the main region are defined by arc-shaped grooves opened in the end face of the pump body, and communicate with the pump discharge passage (main discharge port 22). The pump cover 50 is formed with a communication passage 16 that allows the sub back pressure chambers 11 and 12 to communicate with each other.

  Thereby, the pump discharge pressure generated in the main discharge port 22 is always guided to the main back pressure chambers 11 and 12 as a high pressure, and the vane 3 is pushed out from the slit 2 a and slidably contacts the inner peripheral cam surface 4 a of the cam ring 4.

  The sub back pressure chambers 13 and 14 provided in the sub region are defined by arc-shaped grooves opened in the end face of the pump cover 50, and selectively communicate with the pump discharge passage and the tank passage 45 through the switching valve 60. Is done.

  The pump cover 50 is formed with a communication passage 15 that allows the sub back pressure chambers 13 and 14 to communicate with each other.

  Hereinafter, the switching valve 60 and a specific configuration related thereto will be described.

  The pump cover 50 includes sub back pressure passages 33 and 34 that communicate with the sub back pressure chambers 13 and 14, a sub suction port communication passage 43 that communicates with the sub suction port 23, and a sub discharge port that communicates with the sub discharge port 24. A communication path 44 is formed.

  The pump cover 50 is formed with a valve accommodating hole 51 in which the spool 52 is slidably accommodated.

  In the valve housing hole 51, a tank passage 45 communicating with the tank side (not shown), the sub back pressure passages 33 and 34, the sub suction port communication passage 43, the sub discharge port communication passage 44, the main suction flow passage 20 (main The suction port 21) and the sub suction passage 25 (sub suction port 23) are opened. Further, two valve communication passages 63 and 64 are opened at predetermined positions in the valve accommodating hole 51.

  The spool 52 is driven in the axial direction by an actuator (not shown), and is switched between a full discharge position shown in FIG. 1 and a half discharge position shown in FIG.

  The actuator is constituted by an electric motor, but is not limited thereto, and the spool 52 may be driven by pilot pressure.

  A controller (not shown) controls the operation of the actuator according to, for example, the traveling speed of the vehicle.

  Hereinafter, the operation of the vane pump 1 in the full discharge state in which the switching valve 60 is in the full discharge position and in the half discharge state in the half discharge position will be described.

[All discharge states]
When the spool 52 is in the full discharge position shown in FIG. 1, the passages are communicated as follows.

  The main suction port 21 and the sub suction port 23 are communicated with the tank passage 45.

  The sub discharge port communication passage 44 and the sub back pressure passage 33 are communicated with each other through the valve housing hole 51.

  The valve communication passage 63 connecting the tank passage 45 and the sub back pressure passage 34 is closed by the land portion 53 of the spool 52.

  The valve communication passage 64 connecting the tank passage 45 and the sub back pressure passage 33 is closed by the land portion 54 of the spool 52.

  As a result, the pump discharge pressure generated in the sub discharge port 24 is guided to the sub back pressure chamber 13 via the sub discharge port communication passage 44 and the sub back pressure passage 33, and the sub back pressure chamber 13 passes through the communication passage 15. Guided to the back pressure chamber 14. Since the communication between the sub back pressure passages 33 and 34 with respect to the tank passage 45 is blocked, a high pressure (pump discharge pressure) is generated in the sub back pressure chambers 13 and 14.

  The vane 3 is pushed out in the outer diameter direction from the slit 2a by the high pressure generated in the main back pressure chambers 11 and 12, and the sub back pressure chambers 13 and 14, and the tip portion thereof is in sliding contact with the entire circumference of the inner peripheral cam surface 4a. .

  During the half rotation of the rotor 2, each pump chamber 7 sucks hydraulic oil through the main suction flow path 20 and the main suction port 21, discharges the sucked hydraulic oil from the main discharge port 22, and a pump discharge passage (not shown) To supply to hydraulic equipment.

  Subsequently, in the process of half rotation of the rotor 2, each pump chamber 7 sucks the working oil through the sub suction passage 25 and the sub suction port 23, discharges the sucked working oil from the sub discharge port 24, and pump discharge (not shown) Supply to hydraulic equipment through passage.

  In this way, in the vane pump 1, each pump chamber 7 performs the suction and discharge of the hydraulic oil twice in the process of rotating the rotor 2 once, and the discharge amount of the hydraulic oil is ensured.

(Semi-discharge state)
When the spool 52 is in the half discharge position shown in FIG. 2, the passages are communicated as follows.

  The main suction port 21 communicates with the tank passage 45 via the main suction passage 20 and the valve accommodating hole 51, while the sub suction passage 25 extending from the sub suction port 23 is blocked by the land portion 54 of the spool 52.

  The sub-discharge port communication path 44 extending from the sub-discharge port 24 and the sub-suction port communication path 43 extending from the sub-suction port 23 are communicated with each other via the valve accommodating hole 51.

  The sub back pressure passage 33 is closed by the land portion 55 of the spool 52 with respect to the sub discharge port communication passage 44.

  The sub back pressure passage 33 communicates with the tank passage 45 via the valve communication passage 64.

  The sub back pressure passage 34 communicates with the tank passage 45 via the valve communication passage 63.

  As a result, the pump suction pressure generated in the tank passage 45 is guided to the sub back pressure chamber 13 via the sub back pressure passage 33 and to the sub back pressure chamber 14 via the sub back pressure passage 34. Since the communication of the sub back pressure passage 33 with respect to the sub discharge port communication passage 44 is blocked, a low pressure (pump suction pressure) is generated in the sub back pressure chambers 13 and 14.

  Then, the pump suction pressure generated in the main discharge port 22 is guided to the sub suction port 23 and the sub discharge port 24 through the sub suction port communication path 43, the valve accommodating hole 51, and the sub discharge port communication path 44, and the high pressure ( Pump discharge pressure) occurs.

  During the half rotation of the rotor 2, each vane 3 is caused by a pressure difference between the low pressure generated in the sub back pressure chambers 13 and 14 and the high pressure generated in the sub suction port 23 and the sub discharge port 24 when the sub region makes a half turn. Then, it is drawn in the inner diameter direction of the slit 2a and is separated from the inner peripheral cam surface 4a over a substantially half circumference. Thereby, the pump chambers 7 communicate with each other in the cam ring 4, and the suction and discharge of the hydraulic oil are not performed in the sub-region.

  Subsequently, during the half rotation of the rotor 2, each vane 3 has a slit 2 a due to a pressure difference between the high pressure generated in the main back pressure chambers 11 and 12 and the low pressure generated in the sub suction port 23 when making a half turn around the main region. And is slidably contacted with the inner circumferential cam surface 4a over a substantially half circumference. Thus, each pump chamber 7 sucks the working oil through the main suction port 21, discharges the sucked working oil from the main discharge port 22, and supplies it to the hydraulic equipment through a pump discharge passage (not shown).

  In this way, in the vane pump 1, in the process of rotating the rotor 2 once, each pump chamber 7 performs the suction and discharge of the hydraulic oil only once, and the discharge amount of the hydraulic oil is halved.

  As described above, in the present embodiment, the rotor 2 that is rotationally driven, the plurality of vanes 3 that slidably protrude from the rotor 2, and the cam ring in which the tip portion of the vane 3 is in sliding contact with the inner peripheral cam surface 4a. 4 and a pump chamber 7 defined between the cam ring 4 and the vane 3, and has a main region and a sub region for sucking and discharging the working fluid as the rotor 2 rotates, A vane pump 1 having a switching valve 60 for switching between a full discharge position for sucking and discharging working fluid in both the main region and the sub region and a half discharge position for sucking and discharging working fluid only in the main region. The valve 60 is configured to switch the pressure guided to the vane 3 in the sub-region so that the vane 3 is drawn into the rotor 2 and separated from the inner circumferential cam surface 4a of the cam ring 4 at the half discharge position.

  Based on the above-described configuration, the vane pump 1 sucks in the semi-discharge state in which the switching valve 60 is switched to the semi-discharge position, because the vane 3 in the sub region is drawn into the rotor 2 and separated from the inner circumferential cam surface 4a of the cam ring 4. The pump chamber 7 communicates with each other over the region and the discharge region, and the hydraulic oil is not sucked and discharged. For this reason, the vane pump 1 does not circulate the hydraulic oil wastefully and reduces the horsepower consumed to drive the rotor 2 compared to the conventional device in which the hydraulic oil is sucked and discharged in the sub-region even in the half discharge state. In addition, the temperature rise of the hydraulic oil can be suppressed.

  Further, when the vane pump 1 is switched to the semi-discharge state by the operation of the switching valve 60, the suction amount of the hydraulic oil is suppressed, so that the hydraulic oil is smoothly sucked into the pump chamber 7 even at a high speed, and cavitation occurs. Can be prevented.

  Furthermore, the vane pump 1 in the present embodiment includes a sub suction port 23 that guides hydraulic oil supplied to the pump chamber 7 in the sub region, a sub discharge port 24 that guides hydraulic oil discharged from the pump chamber 7, Sub back pressure chambers 13 and 14 defined behind, and the switching valve 60 guides the pump discharge pressure to the sub back pressure chambers 13 and 14 at all discharge positions, and the hydraulic oil is supplied to the sub suction port 23. The pump suction pressure is guided to the sub back pressure chambers 13 and 14 at the half discharge position, and the pump discharge pressure is guided to the sub suction port 23 in communication with the tank passage 45 to be supplied.

  Based on the above configuration, in the vane pump 1, when the switching valve 60 is in the full discharge position, the pump discharge pressure generated in the sub discharge port 24 as a high pressure is guided to the sub back pressure chambers 13 and 14, and the vane pump 1 3 is pushed out from the slit 2 a and comes into sliding contact with the inner peripheral cam surface 4 a of the cam ring 4. When the switching valve 60 is switched to the half discharge position, the pump suction pressure is guided to the sub back pressure chambers 13, 14 and the pump discharge pressure is guided to the sub suction port 23, and the sub back pressure chamber 13, 14 and the sub suction port 23 cause the vane 3 to be drawn into the slit 2a and away from the inner circumferential cam surface 4a of the cam ring 4.

  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.

DESCRIPTION OF SYMBOLS 1 Vane pump 2 Rotor 2a Slit 3 Vane 4 Cam ring 4a Inner circumferential cam surface 7 Pump chamber 11, 12 Main back pressure chamber 13, 14 Sub back pressure chamber 21 Main suction port 22 Main discharge port 23 Sub suction port 24 Sub discharge port 33, 34 Sub back pressure passage 43 Sub suction port communication passage 44 Sub discharge port communication passage 45 Tank passage 51 Valve housing hole 52 Spool 60 Switching valve

Claims (2)

A rotor that is rotationally driven, a plurality of vanes that project slidably from the rotor, a cam ring in which a tip portion of the vane is in sliding contact with an inner peripheral cam surface, and the cam ring and the vane are defined. A main chamber and a sub region that perform suction and discharge of the working fluid as the rotor rotates, and perform suction and discharge of the working fluid in both the main region and the sub region. A vane pump including a switching valve that switches between a full discharge position and a half discharge position for sucking and discharging a working fluid only in the main region,
The switching valve switches a pressure guided to the vane in the sub-region so that the vane is drawn into the rotor and separated from the inner circumferential cam surface of the cam ring at the half discharge position. .   A sub suction port for guiding hydraulic oil supplied to the pump chamber in the sub region, a sub discharge port for guiding hydraulic oil discharged from the pump chamber, and a sub back pressure chamber defined behind the vane The switching valve guides the pump discharge pressure to the sub back pressure chamber in the full discharge position, and communicates the sub suction port with a tank passage to which hydraulic oil is supplied, and the half discharge position. The vane pump according to claim 1, wherein a pump suction pressure is guided to the sub back pressure chamber and a pump discharge pressure is guided to the sub suction port.