JP2007247473A - Variable displacement pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily manufacture an adapter ring, in a variable displacement pump. <P>SOLUTION: This variable displacement pump 10 has the adapter ring 19 fitted to a fitting hole 20 in a pump casing 11, and a cam ring 22 rockably displaceable by being fitted in the adapter ring 19 and forming first and second fluid pressure chambers 41 and 42 between the cam ring and the adapter ring 19. The adapter ring 19 is composed of a circular pipe, and the cam ring 22 has a noncircular outer peripheral surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a variable displacement pump suitable for use in a hydraulic power steering device for automobiles and the like.

As a variable displacement pump, as described in Patent Document 1, a rotor that is fixed to a pump shaft inserted into a pump casing and rotationally driven, and a large number of vanes are accommodated in grooves to be movable in the radial direction. An adapter ring that is fitted in a fitting hole in the pump casing, and is fitted in the adapter ring so as to be swingable and displaceable, forming a pump chamber between the outer periphery of the rotor, and an adapter ring; A cam ring that forms first and second fluid pressure chambers between them, and pressure upstream of a main throttle provided in the pump discharge side passage is introduced into the first fluid pressure chambers, and the main fluid pressure chamber is introduced into the second fluid pressure chambers. A discharge flow rate control device for introducing pressure downstream of the throttle, and the discharge flow rate control device is operated by a pressure difference on the downstream side of the main throttle, and according to the discharge flow rate of the pressure fluid from the pump chamber Supply flow to the first fluid pressure chamber There is made a switching valve device for controlling the pressure.
JP2004-132269

  In the variable displacement pump described in Patent Document 1, both the adapter ring and the cam ring are made of a non-circular body. A cam ring rocking | fluctuation control stopper is protrudingly formed in the internal peripheral surface which forms the 1st fluid pressure chamber of an adapter ring, the rocking | fluctuation limit of the cam ring which maximizes the volume of a pump chamber is controlled, and the 2nd fluid of an adapter ring A cam ring rocking | fluctuation control stopper is protrudingly formed in the internal peripheral surface which forms a pressure chamber, and the rocking | fluctuation limit of the cam ring which makes the volume of a pump chamber the minimum is controlled. A non-circular outer peripheral surface of the cam ring is provided with a convex surface portion that provides a swing fulcrum supported by the inner peripheral surface of the adapter ring and a convex surface portion that holds a seal member that is in sliding contact with the inner peripheral surface of the adapter ring.

  However, both the adapter ring and the cam ring are made of a non-circular body, which increases the manufacturing cost. In order to reduce the processing cost from a raw material, it is possible to use an adapter ring and a cam ring as a sintered body, but further cost reduction is required.

  An object of the present invention is to easily manufacture an adapter ring in a variable displacement pump.

  According to the first aspect of the present invention, there is provided a rotor that is rotationally driven while being fixed to a pump shaft that is inserted into a pump casing, and that accommodates a large number of vanes in a groove and is movable in a radial direction, and a fitting in the pump casing A pump chamber is formed between the adapter ring fitted in the hole and the adapter ring fitted in the adapter ring so as to be swingable and displaceable with the outer periphery of the rotor. And a cam ring that forms a fluid pressure chamber, and a pressure upstream of the main throttle provided in the pump discharge side passage is introduced into the first fluid pressure chamber, and a pressure downstream of the main throttle is introduced into the second fluid pressure chamber. A discharge flow rate control device to be introduced, and the discharge flow rate control device is operated by a pressure difference between the upstream side and the downstream side of the main throttle, and is supplied to the first fluid pressure chamber according to the discharge flow rate of the pressure fluid from the pump chamber. Has a switching valve device that controls the supply fluid pressure The variable displacement pump comprising, an adapter ring is a circular tube, in which the cam ring is to have a non-circular outer peripheral surface.

  According to a second aspect of the present invention, in the first aspect of the present invention, the non-circular outer peripheral surface of the cam ring is provided on a convex surface portion provided with a swing fulcrum supported by the inner peripheral surface of the adapter ring, and an inner peripheral surface of the adapter ring. A convex surface portion that holds the sealing material that is in sliding contact and a cam ring swing restriction stopper that contacts the inner peripheral surface of the adapter ring are provided.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the adapter ring comprises a drawn tube.

  According to a fourth aspect of the invention, in the invention according to any one of the first to third aspects, the cam ring is made of a sintered body.

  A fifth aspect of the present invention is an automotive hydraulic power steering apparatus using the variable displacement pump according to any one of the first to fourth aspects.

(Claim 1)
(a) Collect the convex parts that need to be provided on either one of the corresponding parts of the adapter ring and cam ring on the outer peripheral surface of the cam ring, and as a result, make the adapter ring consist of a simple circular tube, and easily Made it possible to manufacture.

(Claim 2)
(b) On the non-circular outer peripheral surface of the cam ring, a convex surface portion provided with a swinging fulcrum supported by the inner peripheral surface of the adapter ring, a convex surface portion holding a sealing material slidably contacting the inner peripheral surface of the adapter ring, and the adapter ring It is possible to provide a convex surface portion provided with a cam ring swing restricting stopper that comes into contact with the inner peripheral surface of the cam ring.

(Claim 3)
(c) By making the circular tube of the adapter ring to be a drawn tube, the adapter ring can be manufactured more easily.

(Claim 4)
(d) By making the cam ring a sintered body, the processing cost from the material of the cam ring can be reduced.

(Claim 5)
(e) By applying the variable displacement pumps (a) to (d) described above to an automotive hydraulic power steering device, the cost of the automotive hydraulic power steering device can be reduced.

  1 is a sectional view showing a variable displacement pump, FIG. 2 is a sectional view taken along the line II-II in FIG. 1, FIG. 3 is a sectional view showing an adapter ring, and FIG. 4 is a sectional view showing a cam ring.

  The variable displacement pump 10 is a vane pump serving as a hydraulic pressure generation source of a hydraulic power steering device of an automobile. As shown in FIGS. 1 and 2, the variable displacement pump 10 is rotationally driven by being fixed to a pump shaft 12 inserted into a pump casing 11 by serrations. The rotor 13 is provided. The pump casing 11 is configured by integrating a pump housing 11A and a cover 11B with bolts 14. The pump shaft 12 is supported by a bearing 16A (bush) provided in the support hole 15A of the pump housing 11A and a bearing 16B (bush) provided in the support hole 15B of the cover 11B. An oil seal 16C is fitted in the support hole 15A.

  The rotor 13 accommodates the vanes 17 in grooves 13A provided at a plurality of positions in the circumferential direction, and the vanes 17 can be moved in the radial direction along the grooves 13A.

  In the fitting hole 20 of the pump housing 11A of the pump casing 11, a pressure plate 18 and an adapter ring 19 are fitted in a laminated state, and these are positioned on the side by the cover 11B while being positioned in a circumferential direction by a fulcrum pin 21 described later. It is fixed and held from one side. One end of the fulcrum pin 21 is attached and fixed to the cover 11B.

  A cam ring 22 is fitted on the adapter ring 19 fixed to the pump housing 11 </ b> A of the pump casing 11. The cam ring 22 surrounds the rotor 13 with a certain amount of eccentricity with the rotor 13, and forms a pump chamber 23 between the pressure plate 18 and the cover 11 </ b> B and the outer periphery of the rotor 13. A suction port 24 provided in the cover 11B is opened in the suction region on the upstream side in the rotor rotation direction of the pump chamber 23. The suction port 24 has a suction passage (drain passage) 25A provided in the housing 11A and the cover 11B. The suction port 26 of the pump 10 is communicated with each other. On the other hand, a discharge port 27 provided in the pressure plate 18 opens in a discharge region on the downstream side of the rotor rotation direction of the pump chamber 23, and the discharge port 27 has a high pressure chamber 28A provided in the housing 11A, a discharge passage (non-passage). The discharge port 29 of the pump 10 is communicated with each other via the figure.

  Thus, in the variable displacement pump 10, when the rotor 13 is rotationally driven by the pump shaft 12 and the vane 17 of the rotor 13 is pressed against the cam ring 22 by centrifugal force and rotates, the rotor rotation direction of the pump chamber 23 On the upstream side, the volume surrounded by the adjacent vanes 17 and the cam ring 22 is enlarged as the rotation rotates, and the working fluid is sucked in from the suction port 24. On the downstream side of the pump chamber 23 in the rotor rotation direction, the adjacent vanes 17 and the cam ring 22 The working volume is discharged from the discharge port 27 by reducing the volume enclosed by the rotation.

However, the variable displacement pump 10 has a discharge flow rate control device 40.
The discharge flow rate control device 40 places the aforementioned fulcrum pin 21 on the lowest vertical part of the aforementioned adapter ring 19 fixed to the pump casing 11, and supports the lowest vertical part of the cam ring 22 on this fulcrum pin 21. The cam ring 22 can be oscillated and displaced within the adapter ring 19.

  The cam ring 22 is formed with a cam ring swing restricting stopper 22A projecting on the inner peripheral surface of the adapter ring 19 on a part of the outer peripheral surface forming the first fluid pressure chamber 41, and as will be described later, The swing limit of the cam ring 22 that maximizes the volume is restricted. Further, the cam ring 22 is formed with a cam ring swing restricting stopper 22B projecting on the inner peripheral surface of the adapter ring 19 on a part of the outer peripheral surface forming the second fluid pressure chamber 42, which will be described later. The swing limit of the cam ring 22 that minimizes the volume of the cam ring 22 is restricted.

  The discharge flow rate control device 40 forms first and second fluid pressure chambers 41 and 42 between the cam ring 22 and the adapter ring 19. That is, the first fluid pressure chamber 41 and the second fluid pressure chamber 42 are divided between the cam ring 22 and the adapter ring 19 by the fulcrum pin 21 and the seal material 43 provided at the axially symmetric position. At this time, the first and second fluid pressure chambers 41 and 42 are partitioned on both sides between the cam ring 22 and the adapter ring 19 by the cover 11B and the pressure plate 18, and the cam ring swing restriction stopper 22A of the cam ring 22 described above. , 22B when connecting to the adapter ring 19, the communication groove that connects the first fluid pressure chambers 41 separated on both sides of the stopper 22A, and the second fluid pressure chambers 42 separated on both sides of the stopper 22B. The pressure plate 18 is provided with a communication groove for communication.

  Further, the discharge flow rate control device 40 is screwed into the discharge port 29 of the pump housing 11A constituting the pump casing 11 and the spring retainer 50 is screwed to the opposite side of the first fluid pressure chamber 41 with the cam ring 22 interposed therebetween. A spring 51 as an urging means supported by the spring retainer 50 is brought into contact with the outer surface of the cam ring 22 through a communication hole 52 provided in the adapter ring 19. The spring 51 urges the cam ring 22 between the outer periphery of the rotor 13 in a direction that maximizes the volume of the pump chamber 23 (pump capacity). The spring retainer 50 includes a hollow body that accommodates the communication hole 52 and a cylindrical hollow body that includes one or more discharge holes 53 that constitute a part of the discharge port 29.

  The discharge flow rate control device 40 is provided with a main throttle 54 at an intermediate portion of a discharge passage (not shown). (1) The pressure on the upstream side of the main throttle 54 is applied to the first fluid pressure chamber 41 that gives the cam ring 22 swinging displacement in a direction that minimizes the volume of the pump chamber 23 via a switching valve device 60 described later. (2) The pressure downstream of the main throttle 54 is applied to the second fluid pressure chamber 42 which gives the cam ring 22 a swing displacement in the direction that maximizes the volume of the pump chamber 23 (not shown). To the adapter ring 19 through the communication hole 52. The cam ring 22 is moved against the urging force of the spring 51 according to the balance of the pressures acting on the first fluid pressure chamber 41 and the second fluid pressure chamber 42, and the volume of the pump chamber 23 is changed to change the discharge flow rate of the pump 10. To control.

  Here, the discharge flow rate control device 40 is operated by a pressure difference between the upstream side and the downstream side of the main throttle 54, and is supplied to the first fluid pressure chamber 41 according to the discharge flow rate of the pressure fluid from the pump chamber 23. A switching valve device 60 for controlling the fluid pressure is provided. Specifically, the switching valve device 60 is interposed between a communication path 61 connected to the first fluid pressure chamber 41 and a communication path 67 upstream of the main throttle 54 of the discharge path (not shown). The first fluid pressure chamber 41 is closed to the communication path 67 in the low rotation range of the pump 10 and the first fluid pressure chamber 41 is connected to the communication path 67 in the high rotation range by cooperation with the throttle 61 </ b> A provided in the communication path 61. Connecting.

  The switching valve device 60 accommodates a spring 63 and a switching valve 64 in a valve storage hole 62 formed in the pump housing 11A, and a cap 65 in which the switching valve 64 biased by the spring 63 is screwed to the pump housing 11A. It is supported by. The switching valve 64 includes a valve body 64A that is in close sliding contact with the valve storage hole 62, and a switching valve body 64B. A main throttle 54 of a discharge passage (not shown) is provided in a pressurizing chamber 66A provided on one end side of the valve body 64A. The communication path 67 on the more upstream side communicates with the back pressure chamber 66B in which the spring 63 provided on the other end side of the switching valve body 64B is stored. The communication path on the downstream side of the main throttle 54 of the discharge passage (not shown). 68 communicates with the second fluid pressure chamber 42. Further, the above-described suction passage (drain passage) 25A is formed through the drain chamber 66C between the valve body 64A and the switching valve body 64B and communicates with the tank. The valve body 64A is capable of opening and closing the connecting path 61 described above. That is, in the low rotation range where the discharge pressure of the pump 10 is low, the switching valve 64 is set to the original position shown in FIG. 2 by the biasing force of the spring 63, and the pressurizing chamber 66A is moved to the first fluid pressure chamber 41 by the valve body 64A. The communication path 61 is closed. In the middle and high rotation range of the pump 10, the switching valve 64 is moved by the high-pressure fluid in the communication path 67 applied to the pressurizing chamber 66A, and the pressurizing chamber 66A is connected to the first fluid pressure chamber 41 by the valve body 64A. On the other hand, the high-pressure fluid applied to the pressurizing chamber 66 </ b> A from the communication path 67 is introduced into the first fluid pressure chamber 41. The communication path 67 is provided with a throttle 67A so that pulsation from the upstream side of the main throttle 54 can be absorbed.

Therefore, the discharge flow rate characteristic of the pump 10 using the discharge flow rate control device 40 is as follows.
(1) In a low-speed traveling region of an automobile in which the rotation speed of the pump 10 is low, the pressure of the fluid discharged from the pump chamber 23 and reaching the pressurizing chamber 66A of the switching valve device 60 is still low, and the switching valve 64 is in the original position. The switching valve 64 closes the pressurizing chamber 66A with respect to the communication path 61 to the first fluid pressure chamber 41. Therefore, the pressure on the upstream side of the main throttle 54 is not supplied to the first fluid pressure chamber 41, and the pressure on the downstream side of the main throttle 54 is applied to the second fluid pressure chamber 42. Therefore, the cam ring 22 is maintained on the side where the volume of the pump chamber 23 is maximized by the pressure difference between the first fluid pressure chamber 41 and the second fluid pressure chamber 42 and the biasing force of the spring 51, and the discharge flow rate of the pump 10 is It increases in proportion to the rotation speed.

  (2) When the pressure of the fluid discharged from the pump chamber 23 and reaching the pressurizing chamber 66A of the switching valve device 60 increases due to an increase in the rotation speed of the pump 10, the switching valve device 60 resists the urging force of the spring 63. The switching valve 64 is moved to open the pressurizing chamber 66 </ b> A with respect to the communication path 61 to the first fluid pressure chamber 41. As a result, the pressure in the first fluid pressure chamber 41 increases, and the cam ring 22 moves to the side of reducing the volume of the pump chamber 23. Therefore, the discharge flow rate of the pump 10 maintains a constant flow rate by offsetting the increase in flow rate due to the increase in rotation rate and the decrease in flow rate due to the volume reduction of the pump chamber 23 with respect to the increase in rotation rate.

  The pump 10 has a relief valve 70 as a switching valve that relieves excessive fluid pressure on the pump discharge side between the high pressure chamber 28A, the suction passage (drain passage) 25A, and the drain chamber 66C. is doing. Further, the pump 10 pierces the cover 11B with a lubricating oil supply passage 71 from the suction passage 25A toward the bearing 16B of the pump shaft 12, and returns a lubricating oil return passage 72 (from the circumference of the bearing 16A of the pump shaft 12 to the suction passage 25B. (Not shown) is formed in the pump housing 11A.

  However, the pump 10 has the following configuration in order to easily manufacture the adapter ring 19 and the cam ring 22.

  As shown in FIG. 3, the adapter ring 19 is a circular pipe, and in this embodiment, the adapter ring 19 is a drawn pipe such as a drawn steel pipe. The circular outer peripheral surface of the adapter ring 19 is fitted into the fitting hole 20 of the pump housing 11 </ b> A, and the circular inner peripheral surface of the adapter ring 19 forms first and second fluid pressure chambers 41 and 42.

  As shown in FIG. 4, the cam ring 22 has a non-circular outer peripheral surface, and is made of a sintered body in this embodiment. The non-circular outer peripheral surface of the cam ring 22 holds the convex surface portion 81 provided with the fulcrum pin 21 supported on the inner peripheral surface of the adapter ring 19 and the sealing material 43 slidably in contact with the inner peripheral surface of the adapter ring 19. A convex surface portion 82 and convex surface portions 83 and 84 provided with the above-described cam ring swing restriction stoppers 22A and 22B that come into contact with the inner peripheral surface of the adapter ring 19 are provided. The fulcrum pin 21 is fitted and sandwiched between an arc groove provided on the inner peripheral surface of the adapter ring 19 and an arc groove provided on the convex surface portion 81 of the cam ring 22. The sealing material 43 is fitted and held in a square groove provided in the convex surface portion 82 of the cam ring 22. The circular inner peripheral surface of the cam ring 22 forms a pump chamber 23, and the vane 17 of the rotor 13 is pressed and brought into sliding contact.

According to the present embodiment, the following operational effects can be obtained.
(a) Convex surfaces 81, 82, 83, 84 that are required to be provided on either one of the corresponding portions of the adapter ring 19 and the cam ring 22 are collected on the outer peripheral surface of the cam ring 22, and as a result, the adapter ring 19 is It is made of a simple circular tube and can be manufactured easily.

  (b) A convex surface that holds the fulcrum pin 21 supported on the inner peripheral surface of the adapter ring 19 on the non-circular outer peripheral surface of the cam ring 22 and a convex surface that holds the sealing material 43 that is in sliding contact with the inner peripheral surface of the adapter ring 19. The convex part 83 and 84 which provide the cam ring rocking | fluctuation control stopper 22A, 22B which contact | abuts the part 82 and the inner peripheral surface of the adapter ring 19 can be provided.

  (c) By making the circular tube of the adapter ring 19 a drawing tube, the adapter ring 19 can be manufactured more easily.

  (d) By forming the cam ring 22 from a sintered body, the processing cost from the material of the cam ring 22 can be reduced.

  (e) By applying the variable displacement pump 10 of (a) to (d) described above to an automotive hydraulic power steering device, the cost of the automotive hydraulic power steering device can be reduced.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration of the present invention is not limited to this embodiment, and even if there is a design change or the like without departing from the gist of the present invention. It is included in the present invention.

FIG. 1 is a sectional view showing a variable displacement pump. FIG. 2 is a sectional view taken along line II-II in FIG. 3 is a cross-sectional view showing the adapter ring. FIG. 4 is a cross-sectional view showing the cam ring.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Variable displacement pump 11 Pump casing 12 Pump shaft 13 Rotor 13A Groove 17 Vane 19 Adapter ring 20 Fitting hole 21 A fulcrum pin (oscillation fulcrum)
22 Cam ring 23 Pump chamber 40 Discharge flow rate control device 41 First fluid pressure chamber 42 Second fluid pressure chamber 54 Main throttle 60 Switching valve devices 81, 82, 83, 84 Convex surface

Claims (5)

A rotor that is fixed to a pump shaft inserted into a pump casing and is rotationally driven, and a large number of vanes are accommodated in grooves and movable in a radial direction,
An adapter ring to be fitted into a fitting hole in the pump casing;
A cam ring which is fitted in the adapter ring and can be oscillated and displaced, forms a pump chamber with the outer periphery of the rotor, and forms first and second fluid pressure chambers with the adapter ring; ,
A discharge flow rate control device that introduces pressure upstream of the main throttle provided in the pump discharge side passage into the first fluid pressure chamber and introduces pressure downstream of the main throttle into the second fluid pressure chamber;
The discharge flow rate control device is operated by a pressure difference between the upstream and downstream sides of the main throttle, and has a switching valve device that controls the supply fluid pressure to the first fluid pressure chamber according to the discharge flow rate of the pressure fluid from the pump chamber. In the variable displacement pump,
The adapter ring consists of a circular tube,
A variable displacement pump characterized in that the cam ring has a non-circular outer peripheral surface.   A non-circular outer peripheral surface of the cam ring has a convex surface portion that provides a swing fulcrum supported by the inner peripheral surface of the adapter ring, a convex surface portion that holds a sealing material that is in sliding contact with the inner peripheral surface of the adapter ring, and an inner surface of the adapter ring. The variable displacement pump according to claim 1, further comprising a convex surface portion provided with a cam ring swing regulating stopper that comes into contact with the peripheral surface.   The variable displacement pump according to claim 1 or 2, wherein the adapter ring comprises a drawn tube.   The variable displacement pump according to any one of claims 1 to 3, wherein the cam ring is made of a sintered body.   An automotive hydraulic power steering apparatus using the variable displacement pump according to any one of claims 1 to 4.

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