JP2010255551A - Variable displacement vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a variable displacement vane pump suppressing enlargement of a pump body even if the pressure in the pump is increased. <P>SOLUTION: This variable displacement vane pump 1 varying discharge capacity of working fluid is configured to include first cam ring drive chamber pressure lead-out means (a through hole 11a and a first cam ring drive chamber communication passage 21) for leading pressure P1 in a first cam ring drive chamber 31 to between a peripheral surface 11b of an adapter ring 11 and an inner wall surface 10c of the pump body 10. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a variable displacement vane pump that can vary the discharge capacity of a working fluid.

  2. Description of the Related Art In general, a variable displacement vane pump is used as a hydraulic pressure supply source that supplies hydraulic oil to a power steering system of a vehicle.

  Conventionally, as this type of variable displacement vane pump, for example, there is one disclosed in Patent Document 1.

  An annular adapter ring that surrounds the cam ring, a pump body that accommodates the adapter ring, a first cam ring driving chamber and a second cam ring that are defined between the outer peripheral surface of the cam ring and the inner peripheral surface of the adapter ring. A drive chamber and a control valve for controlling the pressure of the hydraulic fluid guided to the first cam ring drive chamber and the second cam ring drive chamber are provided.

  In this variable displacement vane pump, since the discharge pressure of the hydraulic oil is guided to the gap between the outer peripheral surface of the adapter ring and the inner wall surface of the pump body, the pump body functions as a pressure wall that holds the discharge pressure of the hydraulic oil. .

JP 2002-349450 A

  However, in such a conventional variable displacement vane pump, since the pressure such as the discharge pressure is guided to the inner wall surface of the pump body, the pump is increased when the pressure such as the discharge pressure is increased. There is a problem that the rigidity required for the body is increased, the pump body is thickened, and its size is increased.

  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 an increase in size of a pump body even if the pressure of the pump is increased.

  The present invention relates to a variable displacement vane pump having a variable discharge volume of a working fluid, wherein a rotor that is rotationally driven, a plurality of vanes that slidably protrude from the rotor, and a tip of the vane are in sliding contact with each other. A cam ring that defines a pump chamber between the vanes, an annular adapter ring that surrounds the cam ring, a pump body that accommodates the adapter ring, and an outer peripheral surface of the cam ring and an inner peripheral surface of the adapter ring. A first cam ring driving chamber and a second cam ring driving chamber, a control valve for controlling the pressure of the working fluid guided to the first cam ring driving chamber and the second cam ring driving chamber, and an outer peripheral surface of the adapter ring. And a first cam ring driving chamber pressure deriving means for guiding the pressure of the first cam ring driving chamber between the first cam ring and an inner wall surface of the pump body. It was as.

  According to the present invention, since the pressure of the first cam ring driving chamber is guided to the inner wall surface of the pump body, the pressure of the working fluid applied to the inner wall surface of the pump body at the time of high load operation as compared with the conventional device in which the discharge pressure is guided. The required value of the rigidity against the expansion deformation of the pump body is lowered as compared with the conventional device. As a result, it is possible to realize a variable displacement vane pump that can suppress an increase in size of the pump body even if the pressure of the pump is increased.

Sectional drawing of the variable displacement vane pump which shows embodiment of this invention. Sectional drawing of a cover, an adapter ring, and a pump body. Sectional drawing of the cover which shows other embodiment, an adapter ring, and a pump body. Sectional drawing of the cover which shows other embodiment, an adapter ring, and a pump body. Sectional drawing of the cover which shows other embodiment, an adapter ring, and a pump body. Sectional drawing of the cover which shows other embodiment, an adapter ring, and a pump body.

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

  FIG. 1 is a cross-sectional view showing a cross section perpendicular to the axial direction of the drive shaft 9 in a variable displacement vane pump 1 (hereinafter simply referred to as “vane pump”).

  The power of the engine (not shown) is transmitted to the drive shaft 9, and the rotor 2 rotates counterclockwise by the drive shaft 9 as indicated by an arrow in the figure.

  The vane pump 1 accommodates a plurality of vanes 3 provided so as to be capable of reciprocating in the radial direction of the rotor 2 as a pump mechanism, and the rotor 2, and the vane 3 is arranged on the inner cam surface as the rotor 2 rotates. And a cam ring 4 that slides at the tip and is eccentric with respect to the center of the rotor 2. A pump chamber 7 partitioned by each vane 3 is defined between the rotor 2 and the cam ring 4.

  As the rotor 2 rotates, the volume of the pump chamber 7 expands and contracts. When the pump chamber 7 passes through the suction region above the drive shaft 9 in FIG. 1, the volume of the pump chamber 7 expands, and the working fluid in the tank 20 is sucked from the suction port 15 through the suction passage 19. On the other hand, when the pump chamber 7 passes through the discharge region below the drive shaft 9 in FIG. 1, its volume contracts and discharges the pressurized working fluid from the discharge port 16, and this pressurized working fluid is discharged. It is supplied to the power steering system 24 mounted on the vehicle through the passage 26.

  In the vane pump 1, hydraulic oil (oil) is used as a working fluid circulating through the vane pump 1, but a water-soluble alternative liquid or the like may be used instead of the hydraulic oil.

  The vane pump 1 includes a bottomed cylindrical pump body 10 as a structure that houses the pump mechanism, a cover 60 (not shown) that is fastened in contact with the opening end 10a of the pump body 10, and a pump (see FIG. 2). The adapter ring 11 is interposed inside the body 10 and the cover 60. A pump mechanism including the cam ring 4, the vane 3, the rotor 2 and the like is accommodated inside the annular adapter ring 11.

  A side plate 5 (see FIG. 2) is accommodated in the bottom of the pump body 10, and the end surface of the adapter ring 11 contacts the side plate 5 and the end surfaces of the cam ring 4, the vane 3, and the rotor 2 are in sliding contact with each other.

  The vane pump 1 includes a variable displacement mechanism that changes the amount of eccentricity of the cam ring 4 with respect to the rotor 2. As this variable capacity mechanism, a support pin 13 is interposed between the adapter ring 11 and the cam ring 4. When the cam ring 4 swings around the support pin 13 as a fulcrum, the eccentric amount of the cam ring 4 with respect to the rotor 2 changes, and the discharge capacity (pump displacement volume) of the pump chamber 7 changes.

  A seal material 14 is interposed between the adapter ring 11 and the cam ring 4. A first cam ring drive chamber 31 and a second cam ring drive chamber 32 are defined between the outer peripheral surface of the cam ring 4 and the inner peripheral surface 11 c of the adapter ring 11 by the support pins 13 and the seal material 14. The cam ring 4 swings about the support pin 13 as a fulcrum by the pressure difference of the working fluid in the first cam ring drive chamber 31 and the second cam ring drive chamber 32.

  A coiled cam spring 18 is interposed between the cam ring 4 and the adapter ring 11 by being compressed. The cam spring 18 biases the cam ring 4 in a direction in which the amount of eccentricity with respect to the rotor 2 increases.

  As a pressure control means for moving the cam ring 4, a flow rate detection orifice 56 is interposed in the discharge passage 26, and is guided to the first cam ring drive chamber 31 and the second cam ring drive chamber 32 according to the differential pressure across the flow rate detection orifice 56. A control valve 41 for controlling the working fluid pressure is provided.

  A discharge pressure introduction passage 27 is provided for introducing a discharge pressure P0 generated upstream of the flow rate detection orifice 56 of the discharge passage 26 into the second cam ring drive chamber 32, and an orifice 57 is interposed in the discharge pressure introduction passage 27.

  The control valve 41 includes a spool 42 that is slidably inserted into the control valve housing hole 10b. The opening end of the control valve accommodating hole 10 b is sealed with a plug 43. A coiled return spring 46 is compressed and interposed between the bottom of the control valve accommodating hole 10b and the spool 42.

  A differential pressure across the flow rate detection orifice 56 is guided to both ends of the spool 42 via the first and second discharge pressure introduction passages 28 and 29. An orifice 59 is interposed in the second discharge pressure introduction passage 29. The spool 42 moves to the right in FIG. 1 against the biasing force of the return spring 46 as the differential pressure across the flow rate detection orifice 56 increases.

  The control valve housing hole 10 b communicates with the first cam ring drive chamber communication passage 21 that communicates with the first cam ring drive chamber 31, the second cam ring drive chamber communication passage 22 that communicates with the second cam ring drive chamber 32, and the tank 20. The drain passages 23 are connected to each other. The first cam ring drive chamber communication passage 21, the second cam ring drive chamber communication passage 22, and the drain passage 23 are opened / closed depending on the position of the spool 42, and the working fluid is guided to the first cam ring drive chamber 31 and the second cam ring drive chamber 32. The pressure is adjusted.

  When the rotational speed of the rotor 2 is lower than a predetermined value, the differential pressure across the flow rate detection orifice 56 is smaller than the predetermined value, so that one end of the spool 42 abuts against the plug 43 by the urging force of the return spring 46. Hold in initial position. In this initial position, communication between the first cam ring drive chamber communication passage 21 and the first discharge pressure introduction passage 28 is blocked by the spool 42 and communication between the second cam ring drive chamber communication passage 22 and the drain passage 23 is established. Therefore, the cam ring 4 is held at the initial position where the eccentric amount with respect to the rotor 2 is maximized by the discharge pressure P0 guided from the discharge pressure introduction passage 27 to the second cam ring drive chamber 32 and the urging force of the cam spring 18. Is done. In this state, the vane pump 1 discharges the working fluid, and the discharge flow rate increases substantially in proportion to the rotational speed of the rotor 2. Thereby, even when the rotation speed of the rotor 2 is low, a sufficient amount of working fluid is supplied to the power steering system 24.

  On the other hand, when the rotational speed of the rotor 2 is increased to a predetermined value or higher, the spool 42 resists the biasing force of the return spring 46 as the differential pressure across the flow rate detection orifice 56 increases to a predetermined value or higher. 1, the first cam ring drive chamber 31 and the first discharge pressure introduction passage 28 are communicated with each other, and the second cam ring drive chamber 32 and the drain passage 23 are communicated with each other to drive the first cam ring drive. The pressure P1 in the chamber 31 is higher than the pressure P2 in the second cam ring drive chamber 32. The cam ring 4 moves in a direction in which the amount of eccentricity with respect to the rotor 2 decreases (rightward in FIG. 1) according to the pressure difference between the first cam ring driving chamber 31 and the second cam ring driving chamber 32. In this state, the vane pump 1 is adjusted to a pump discharge capacity corresponding to the differential pressure across the flow rate detection orifice 56. As a result, the flow rate of the working fluid supplied to the power steering system when the vehicle is running is appropriately adjusted so as not to become excessive.

  Further, when the load applied to the power steering system 24 is increased, the pressure generated in the pump chamber 7 increases, the leakage of the pump internal pressure increases, and the pump discharge flow rate decreases. As a result, the differential pressure across the flow detection orifice 56 decreases, and the spool 42 moves in a direction in which the communication between the first cam ring drive chamber 31 and the first discharge pressure introduction passage 28 is blocked by the urging force of the return spring 46. At the same time, the communication between the second cam ring drive chamber 32 and the drain passage 23 is also blocked, and the pressure P1 in the first cam ring drive chamber 31 decreases due to leakage into the drain passage 23 through the notch 45. . The cam ring 4 is held at a position where the pressure difference (P2-P1) between the first cam ring drive chamber 31 and the second cam ring drive chamber 32 and the urging force of the cam spring 18 are balanced.

  Thus, in the operating state in which the load of the vane pump 1 increases, the pressure P1 of the first cam ring drive chamber 31 becomes lower than the discharge pressure P0 of the discharge passage 26, and as described above, the first cam ring drive chamber 31 and the second cam ring Based on the communication state between the drive chamber 32 and the drain passage 23, the pressure P1 of the first cam ring drive chamber 31 becomes lower than the pressure P2 of the second cam ring drive chamber 32.

  When the pressure is increased to increase the discharge pressure of the vane pump 1, the rigidity required for the pump body 10 is increased.

  The present invention focuses on the pressure of the first cam ring drive chamber 31 during the high load operation described above, and the pressure of the first cam ring drive chamber 31 is between the outer peripheral surface 11b of the adapter ring 11 and the inner wall surface 10c of the pump body 10. The first cam ring driving chamber pressure deriving means for guiding P1 is provided, and the pressure P3 generated between the adapter ring 11 and the pump body 10 in an operation state in which the load of the vane pump 1 is increased is lower than the discharge pressure. The gist is to ensure rigidity.

  As the first cam ring drive chamber pressure deriving means, a plurality of (for example, two) through holes 11a penetrating the adapter ring 11 are formed. One end of the through hole 11a communicates with the first cam ring drive chamber 31, the other end communicates with the adapter ring 11 and the adapter ring outer peripheral clearance 8 of the pump body 10, and the pressure P1 of the first cam ring drive chamber 31 is adapted to the adapter ring. It fulfills the function of first cam ring drive chamber pressure deriving means that leads to the outer circumferential gap 8.

  The adapter ring 11 has an unbroken ring shape, and the communication between the first cam ring drive chamber 31 and the adapter ring outer peripheral gap 8 is blocked between the cover 60 and the side plate 5 as shown in FIG. It constitutes a metal seal.

  The first cam ring drive chamber communication passage 21 that communicates the first cam ring drive chamber 31 with the control valve accommodating hole 10 b is configured by a through hole 10 d formed in the pump body 10 and a through hole 11 d that penetrates the adapter ring 11. The Thus, the first cam ring drive chamber communication passage 21 is provided through the adapter ring outer peripheral gap 8, and the first cam ring drive chamber pressure deriving means that guides the pressure P 1 of the first cam ring drive chamber 31 to the adapter ring outer peripheral gap 8. Fulfills the function.

  The adapter ring outer peripheral gap 8 is provided as an annular gap between the outer peripheral surface 11 b of the adapter ring 11 and the inner wall surface 10 c of the pump body 10. An annular groove or the like may be formed on the outer peripheral surface 11 b of the adapter ring 11 or the inner wall surface 10 c of the pump body 10 to provide a fluid pressure chamber that guides the working fluid along the outer periphery of the adapter ring 11.

  The second cam ring drive chamber communication passage 22 and the discharge pressure introduction passage 27 communicating with the second cam ring drive chamber 32 are formed in the side plate 5 or the cover 60 without penetrating the adapter ring 11. As a result, the pressure P2 of the second cam ring drive chamber 32 is not guided to the adapter ring outer peripheral gap 8.

  The pressure P1 of the working fluid applied to the inner wall surface 10c of the pump body 10 in the adapter ring outer peripheral clearance 8 is set by the pressure P1 in the first cam ring driving chamber 31 being guided to the adapter ring outer peripheral clearance 8 as described above. It becomes substantially equal to the pressure P1 of the first cam ring drive chamber 31.

  That is, since the pressure P1 of the first cam ring drive chamber 31 is guided to the inner wall surface 10c of the pump body 10, the pressure of the working fluid applied to the inner wall surface 10c of the pump body 10 is higher than that of the conventional device in which the discharge pressure is guided. The required value of the rigidity with respect to the expansion deformation of the pump body 10 can be reduced as compared with the conventional device.

  For example, during a high load operation in which the discharge pressure P0 of the discharge passage 26 is 13.5 MPa, the pressure in the first cam ring drive chamber 31 is adjusted to about 12.0 MPa, and the pressure difference is about 1.5 MPa. In this way, the variable displacement vane pump 1 can be provided in which the increase in size of the pump body 10 is suppressed by suppressing the pressure of the working fluid applied to the inner wall surface 10c of the pump body 10 to be as low as about 12.0 MPa.

  In the present embodiment, a variable displacement vane pump 1 having a variable working fluid discharge capacity, a rotor 2 that is rotationally driven, a plurality of vanes 3 that slidably protrude from the rotor 2, and the vanes. 3, a cam ring 4 that defines a pump chamber 7 between the vanes 3 by sliding the tip of 3, an annular adapter ring 11 that surrounds the cam ring 4, and a pump body 10 that houses the adapter ring 11, A first cam ring driving chamber 31 and a second cam ring driving chamber 32 defined between the outer peripheral surface of the cam ring 4 and the inner peripheral surface 11c of the adapter ring 11, and the first cam ring driving chamber 31 and the second cam ring driving chamber. 32, control valve 41 for controlling the pressures P1 and P2 of the working fluid respectively led to 32, outer peripheral surface 11b of adapter ring 11 and inner wall surface 10 of pump body 10 The first cam ring driving chamber pressure deriving means (through hole 11a, first cam ring driving chamber communication path 21) for guiding the pressure P1 of the first cam ring driving chamber 31 between the adapter ring 11 and the pump during high load operation The pressure P3 generated between the bodies 10 is configured to be lower than the discharge pressure.

  Based on the above configuration, since the pressure P1 of the first cam ring drive chamber 31 is guided to the inner wall surface 10c of the pump body 10, the inner wall surface 10c of the pump body 10 is operated at a higher load operation than in the conventional device in which the discharge pressure is guided. The pressure of the working fluid applied to the pump body 10 becomes lower, and the required rigidity value for the expansion deformation of the pump body 10 is lower than that of the conventional device.

  As a result, it is possible to realize the variable displacement vane pump 1 that can suppress an increase in size of the pump body even if the pressure of the pump is increased.

  In the present embodiment, the first cam ring driving chamber pressure deriving means is configured to include a through hole 11 a that penetrates the adapter ring 11.

  Based on the above configuration, the working fluid pressure in the first cam ring drive chamber 31 is guided between the outer peripheral surface 11b of the adapter ring 11 and the inner wall surface 10c of the pump body 10 through the through hole 11a.

  In the present embodiment, the first cam ring drive chamber communication passage 21 that communicates the control valve 41 and the first cam ring drive chamber 31 is configured to penetrate the adapter ring 11 as the first cam ring drive chamber pressure deriving means.

  Based on the above configuration, the working fluid pressure in the first cam ring drive chamber 31 is guided between the outer peripheral surface 11 b of the adapter ring 11 and the inner wall surface 10 c of the pump body 10 through the first cam ring drive chamber communication passage 21.

  As another embodiment, as shown in FIG. 3, a groove 61 may be formed in the cover 60 as the first cam ring driving chamber pressure deriving means. The groove 61 constitutes first cam ring driving chamber pressure deriving means that communicates the first cam ring driving chamber 31 with the adapter ring outer circumferential gap 8 and guides the pressure P1 of the first cam ring driving chamber 31 to the adapter ring outer circumferential gap 8.

  As yet another embodiment, as shown in FIG. 4, a groove 62 may be formed in the side plate 5 as the first cam ring driving chamber pressure deriving means. The groove 62 communicates the first cam ring drive chamber 31 and the adapter ring outer peripheral gap 8 to constitute first cam ring drive chamber pressure deriving means for guiding the pressure P1 of the first cam ring drive chamber 31 to the adapter ring outer peripheral gap 8.

  Further, the side plate 5 may be integrated with the pump body 10 and a groove as a first cam ring driving chamber pressure deriving means may be formed in the pump body 10.

  In addition, you may form the groove | channel as a 1st cam ring drive chamber pressure derivation | leading-out means in the side surface of the adapter ring 11. FIG.

  As yet another embodiment, as shown in FIG. 5, a through hole 63 may be formed in the cover 60 as the first cam ring driving chamber pressure deriving means. This through hole 63 communicates the first cam ring drive chamber 31 and the adapter ring outer peripheral gap 8 to constitute first cam ring drive chamber pressure deriving means for guiding the pressure P1 of the first cam ring drive chamber 31 to the adapter ring outer peripheral gap 8.

  As yet another embodiment, as shown in FIG. 6, a through hole 64 may be formed in the side plate 5 as the first cam ring driving chamber pressure deriving means. The through hole 64 communicates the first cam ring driving chamber 31 and the adapter ring outer peripheral gap 8 to constitute first cam ring driving chamber pressure deriving means for guiding the pressure P1 of the first cam ring driving chamber 31 to the adapter ring outer peripheral gap 8.

  Alternatively, the side plate 5 may be integrated with the pump body 10 and a through hole may be formed in the pump body 10 as first cam ring drive chamber pressure deriving means.

  In these embodiments, the groove (61, 62) or the through hole (63, 64) is formed in the member that contacts the adapter ring 11 and defines the first cam ring drive chamber 31.

  Based on the above configuration, the working fluid pressure in the first cam ring drive chamber 31 passes through the grooves (61, 62) or the through holes (63, 64), and the outer peripheral surface 11b of the adapter ring 11 and the inner wall surface 10c of the pump body 10 Led in between.

  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 Variable displacement type vane pump 2 Rotor 3 Vane 4 Cam ring 7 Pump chamber 8 Adapter ring outer periphery clearance 10 Pump body 10c Inner wall surface 11 Adapter ring 11a Through hole (first cam ring drive chamber pressure derivation means)
11b Outer peripheral surface 13 Support pin 14 Sealing material 15 Suction port 16 Discharge port 18 Cam spring 21 First cam ring drive chamber communication path (first cam ring drive chamber pressure deriving means)
22 Second cam ring drive chamber communication passage 23 Drain passage 24 Power steering system 26 Discharge passage 27 Discharge pressure introduction passage 28 First discharge pressure introduction passage 29 Second discharge pressure introduction passage 31 First cam ring drive chamber 32 Second cam ring drive chamber 41 Control valve 42 Spool

Claims (4)

A variable displacement vane pump that makes the discharge capacity of the working fluid variable,
A rotor that is driven to rotate;
A plurality of vanes projecting slidably from the rotor;
A cam ring that slides the tip of the vane to define a pump chamber between the vanes;
An annular adapter ring surrounding the cam ring;
A pump body that houses the adapter ring;
A first cam ring driving chamber and a second cam ring driving chamber defined between an outer peripheral surface of the cam ring and an inner peripheral surface of the adapter ring;
A control valve for controlling the pressure of the working fluid guided to each of the first cam ring driving chamber and the second cam ring driving chamber;
A variable displacement vane pump comprising a first cam ring driving chamber pressure deriving means for guiding the pressure of the first cam ring driving chamber between an outer peripheral surface of the adapter ring and an inner wall surface of the pump body. .   2. The variable displacement vane pump according to claim 1, wherein the first cam ring drive chamber pressure derivation means includes a through-hole penetrating the adapter ring.   2. The first cam ring drive chamber pressure derivation means is provided with a first cam ring drive chamber communication passage that communicates the control valve and the first cam ring drive chamber through the adapter ring. The variable displacement vane pump described in 1.   2. The groove according to claim 1, wherein a groove or a through hole is formed in the adapter ring or a member that abuts against the adapter ring and defines the first cam ring driving chamber. Variable displacement vane pump.

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