JP2009108779A - Method of manufacturing vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a sintering processing time, and to improve the efficiency of effective use of a sintering furnace at sintering an outer case and a rotor which constitute a vane pump. <P>SOLUTION: In the method of manufacturing a vane pump 10, a molded product B of the rotor 13 is arranged in the hollow part Ai of the annular molded product A of the outer case 19 in the sintering furnace, and the molded products A, B are sintered. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for manufacturing a vane pump, and more particularly to a method for manufacturing an outer case and a rotor constituting the vane pump by sintering.

  A vane pump as described in Patent Literature 1 is fitted in a fitting hole of a pump casing and a rotor fixed to a pump shaft supported by the pump casing, and forms a pump chamber between the outer periphery of the rotor. The outer case that houses the cam ring is formed of a sintered body.

In the prior art, as shown in FIG. 8 (A), an annular molded body A of the outer case is molded, and a large number of annular molded bodies A are arranged on the sintering carbon tray 1 and placed in a sintering furnace, and sintered. A sintered body of the outer case is obtained. Further, as shown in FIG. 8B, a rotor compact B is molded, and a large number of compacts B are placed on a sintering carbon tray 1 and placed in a sintering furnace to be sintered. Get.
JP2001-32781

  In the prior art, sintering of the annular molded body A of the outer case and sintering of the molded body B of the rotor are performed in separate steps. When producing a certain number of vane pumps, the same number of outer case sintered bodies and rotor sintered bodies are required. However, since these are sintered in separate steps, the sintering process takes a long time. Further, the annular molded body A of the outer case has a large space in the hollow portion surrounded by the annular portion, and the space in the hollow portion becomes a useless space and impairs the effective use efficiency of the sintering furnace.

  An object of the present invention is to reduce the sintering process time and improve the effective use efficiency of a sintering furnace when sintering an outer case and a rotor constituting a vane pump.

  According to the first aspect of the present invention, a cam ring that forms a pump chamber between the rotor fixed to the pump shaft supported by the pump casing and the fitting hole of the pump casing and forming the outer periphery of the rotor is accommodated. In a method of manufacturing a vane pump in which an outer case is formed of a sintered body, a rotor molded body is disposed in a hollow portion of an annular molded body of the outer case in a sintering furnace, and the molded body is sintered. It is a thing.

  According to a second aspect of the present invention, in the first aspect of the invention, a large number of sets in which the molded body of the rotor is arranged in the hollow portion of the annular molded body of the outer case are arranged in a sintering tray and placed in a sintering furnace. It is what I did.

(Claim 1)
(a) In the sintering furnace, the rotor compact is placed in the hollow part of the outer case annular compact, and the compacts are sintered. When producing a certain number of vane pumps, the same number of outer case sintered bodies and rotor sintered bodies are required, but they are sintered simultaneously and in the same process in the same furnace. Processing time can be shortened.

  (b) The space of the hollow portion surrounded by the annular portion of the annular molded body A of the outer case is used as a storage space for the molded body B of the rotor. For this reason, the waste of the product occupation space in a sintering furnace decreases, and the effective use efficiency of a sintering furnace can be improved.

(Claim 2)
(c) A large number of sets in which the molded body B of the rotor is arranged in the hollow portion of the annular molded body A of the outer case are arranged in a sintering tray and placed in a sintering furnace. As a result, the processing capacity of the sintering furnace can be utilized to the maximum, and a large number of outer case and rotor sintered bodies can be sintered in a short time (the processing time can be substantially halved).

  1 is a cross-sectional view showing a vane pump, FIG. 2 is a cross-sectional view taken along line II-II in FIG. 1, FIG. 3 shows an annular molded body of an outer case, (A) is a plan view, (B) is a cross-sectional view, 4A and 4B show a molded body of the rotor, FIG. 5A is a plan view, FIG. 5B is a cross-sectional view, and FIG. 5 is a plan view showing a state in which the molded body of the rotor is inserted into the hollow portion of the annular molded body of the outer case; 6A and 6B show the mixed state of the molded body, where FIG. 6A is a plan view, FIG. 7B is a side view, FIG. 7 is an enlarged view of the main part of FIG.

  The vane pump 10 is a variable displacement pump that serves as a hydraulic pressure generation source for a hydraulic power steering device of an automobile. As shown in FIGS. 1 and 2, the vane 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 (ball bearing) and a bearing 16B (bush) provided in the support hole 15A of the pump housing 11A, and a bearing 16C (bush) provided in the support hole 15B of the cover 11B. An oil seal 16D is fitted in the support hole 15A.

  The rotor 13 accommodates long plate-like vanes 17 in grooves 13A provided at a plurality of circumferential positions, and each vane 17 is movable 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 outer case 19 are fitted in a laminated state, and these are positioned on the side by the cover 11B while being positioned in the 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 into the outer case 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 downstream of the pump chamber 23 in the rotor rotation direction. The discharge port 27 has a high pressure chamber 28A and a discharge passage 28B provided in the housing 11A. The discharge port 29 of the pump 10 is communicated with each other.

  Thereby, in the vane pump 10, when the rotor 13 is driven to rotate by the pump shaft 12 and the tip of the vane 17 is pressed against the cam ring 22 by the centrifugal force acting on the vane 17 of the rotor 13, On the upstream side in the rotor rotation direction of the pump chamber 23, the volume enclosed by the space between the adjacent vanes 17 and the cam ring 22 is expanded with rotation, and the working fluid (hydraulic oil) is sucked in from the suction port 24. Then, the volume enclosed by the adjacent vanes 17 and the cam ring 22 is reduced with rotation, and the working fluid is discharged from the discharge port 27.

  As shown in FIG. 2, the vane pump 10 is arranged such that the opening range α around the pump shaft 12 of the discharge port 27 is shifted by an angle β toward the second fluid pressure chamber 42 described later.

The vane 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 lowermost vertical part of the outer case 19 fixed to the pump casing 11, and supports the lowermost vertical part of the cam ring 22 on the fulcrum pin 21. The cam ring 22 can be oscillated and displaced in the outer case 19.

  In the pump housing 11A constituting the pump casing 11, the discharge flow rate control device 40 is screwed in a pressure cylinder 50 on the opposite side of a first fluid pressure chamber 41 (to be described later) with the cam ring 22 interposed therebetween, in a sealed state via an O-ring. The branch communication passage 28C branched from the discharge passage 28B communicates with the oil chamber 51 of the pressurizing cylinder 50, and the piston 52 inserted into the oil chamber 51 passes through the piston hole 53 provided in the outer case 19 to the outer surface of the cam ring 22. Struck with. In addition, a spring 54 as an urging means is disposed in the oil chamber 51 of the pressurizing cylinder 50, and the spring 54 has a capacity of the pump chamber 23 (pump) between the cam ring 22 and the outer peripheral portion of the rotor 13 via the piston 52. It is energizing in the direction that maximizes (capacity). The piston 52 is formed of a cylindrical hollow body having one end closed and a cavity for accommodating the spring 54.

  The outer case 19 is formed with a cam ring movement restricting stopper 19A projectingly at a part of the inner peripheral portion forming the first fluid pressure chamber 41, and the cam ring 22 moves to maximize the volume of the pump chamber 23 as will be described later. The limit is regulated. Further, the outer case 19 is formed with a cam ring movement restricting stopper 19B in a protruding shape on a part of an inner peripheral portion forming a second fluid pressure chamber 42 which will be described later, and the cam ring 22 which minimizes the volume of the pump chamber 23 as will be described later. The movement limit is regulated.

  In addition, the discharge flow rate control device 40 forms first and second fluid pressure chambers 41 and 42 between the cam ring 22 and the outer case 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 outer case 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 by the cover 11B and the pressure plate 18 on both sides between the cam ring 22 and the outer case 19, and the cam ring movement restriction stopper 19A of the outer case 19 described above. , 19B, when the cam ring 22 abuts, the communication groove connecting the first fluid pressure chambers 41 separated on both sides of the stopper 19A, and the second fluid pressure chambers 42 separated on both sides of the stopper 19B are communicated. The pressure plate 18 is provided with a connecting groove.

  Here, the oil chamber 51 of the pressure cylinder 50 described above communicates with the discharge passage 28B of the pump 10 through the communication passage 28C. Thereby, in the discharge path of the pump 10, the pressure fluid discharged from the pump chamber 23 and reaching the discharge passage 28B via the discharge port 27 of the pressure plate 18 and the high pressure chamber 28A of the pump housing 11A is communicated with the communication passage 28C. The oil chamber 51 is filled from the annular groove 55A around the pressure cylinder 50 and the passage 55B opened in the wall surface of the pressure cylinder 50. On the other hand, in the discharge passage 28B, a main throttle 58 is provided downstream of the branch portion of the communication passage 28C.

  Then, the discharge flow rate control device 40 (1) describes the pressure upstream of the main throttle 58 in the first fluid pressure chamber 41 that gives the cam ring 22 displacement in the direction that minimizes the volume of the pump chamber 23. Introduced via the switching valve device 60, (2) the pressure downstream of the main throttle 58 is discharged to the second fluid pressure chamber 42 that gives the cam ring 22 displacement in the direction that maximizes the volume of the pump chamber 23. The oil in the pressure cylinder 50 is introduced from the passage 28B via the branch communication passage 28D through the piston hole 53 of the outer case 19 and (3) the cam ring 22 is displaced in the direction that maximizes the volume of the pump chamber 23. The pressure on the upstream side of the main throttle 58 is introduced into the chamber 51 from the discharge passage 28B via the branch communication passage 28C and the passages 55A and 55B of the pressure cylinder 50. The cam ring 22 is moved against the urging force of the spring 54 by the balance of pressures acting on the first fluid pressure chamber 41, the second fluid pressure chamber 42, and the oil chamber 51 of the pressurizing cylinder 50. Is controlled to control the discharge flow rate of the pump 10.

  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 58, 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 the communication path 61 connected to the first fluid pressure chamber 41 and the communication path 67 on the upstream side of the main throttle 58 of the discharge path 28B. The first fluid pressure chamber 41 is closed with respect 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 61A provided in

  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. The pressurizing chamber 66A provided on one end side of the valve body 64A is upstream of the main throttle 58 of the discharge passage 28B. The communication path 67 is connected to the back pressure chamber 66B in which the spring 63 provided on the other end of the switching valve body 64B is stored, and the communication path 68 downstream of the main throttle 58 of the discharge passage 28B is connected to the second fluid pressure. It communicates through the 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 can open and close the communication 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 58 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. For this reason, the pressure on the upstream side of the main throttle 58 is not supplied to the first fluid pressure chamber 41, and the pressure on the downstream side of the main throttle 58 is applied to the second fluid pressure chamber 42. A pressure on the upstream side of the main throttle 58 is applied to 51. For this reason, the cam ring 22 is a side that maximizes the volume of the pump chamber 23 by the pressure difference between the first fluid pressure chamber 41 and the second fluid pressure chamber 42, the pushing force of the piston 52 of the pressurizing cylinder 50, and the biasing force of the spring 54. The discharge flow rate of the pump 10 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. The pump 10 also has a lubricating oil supply passage 71 (not shown) from the suction passage 25A toward the bearing 15C of the pump shaft 12 formed in the cover 11B, and returns to the suction passage 25B from around the bearing 15B of the pump shaft 12. A return path 72 is formed in the pump housing 11A.

  Accordingly, the pump 10 supports the pump shaft 12 in the support hole 15A of the pump casing 11 (pump housing 11A) by the bearing 16A (ball bearing) and the bearing 16B (bush) as described above, and the support hole 15A of the pump shaft 12 is supported. A pulley 80 is fixed to a projecting portion 12A projecting outward from the vehicle, and is driven to rotate by the engine rotational force of the automobile through the pulley 80. In the pulley 80, the boss 80A is serration-coupled to the serration portion of the projecting portion 12A of the pump shaft 12, and the boss 80A is sandwiched between the inner ring of the bearing 16A by a nut 81 screwed to the outer end screw portion of the projecting portion 12A. Pressed and fixed. Note that the outer ring of the bearing 16A is retained by a retaining ring 82 that is engaged with the inner peripheral groove of the support hole 15A of the pump housing 11A.

  As shown in FIGS. 1 and 3, the pump 10 has an inner peripheral surface 92 of a hole opening 91 facing the outside of the support hole 15A of the pump casing 11 (pump housing 11A) (side of the side wall arm of the pulley 80). It has a tapered shape that expands outward.

  However, in the vane pump 10, the pump 13 is fitted between the rotor 13 fixed to the pump shaft 12 supported by the pump casing 11 and the fitting hole 20 of the pump casing 11 and between the outer periphery of the rotor 13. The outer case 19 that houses the cam ring 22 that forms the chamber 23 is formed of a sintered body. Hereinafter, the sintering method of the outer case 19 and the rotor 13 will be described.

  (1) With respect to the outer case 19, the raw material alloy powder is weighed and mixed, and press-molded into a predetermined shape to obtain an annular molded body A shown in FIG.

  (2) Regarding the rotor 13, the raw material alloy powder is weighed and mixed, and pressed into a predetermined shape to obtain a formed body B shown in FIG. 4.

  (3) One set is formed by inserting the molded body B of the rotor 13 into the hollow portion Ai of the annular molded body A of the outer case 19 as shown in FIG. A large number of sets of the annular molded body A and the molded body B are placed side by side on the sintering carbon tray 100 as shown in FIGS. FIG. 6B shows a state in which a plurality of trays 100 are stacked via spacers 101.

  (4) The tray 100 of the above (3) is placed in a sintering furnace and heat-treated and sintered under predetermined conditions to produce a sintered body of the outer case 19 and a sintered body of the rotor 13.

According to the present embodiment, the following operational effects can be obtained.
(a) In the sintering furnace, the molded body B of the rotor 13 is placed in the hollow portion Ai of the annular molded body A of the outer case 19, and the molded bodies B are sintered. When a certain number of vane pumps 10 are produced, the same number of sintered bodies of the outer case 19 and the sintered body of the rotor 13 are required, but these are sintered in parallel in the same process in the same furnace. In addition, the sintering process time can be shortened.

  (b) The space of the hollow portion Ai surrounded by the annular portion of the annular molded body A of the outer case 19 is used as an accommodation space for the molded body B of the rotor 13. For this reason, the waste of the product occupation space in a sintering furnace decreases, and the effective use efficiency of a sintering furnace can be improved.

  (c) A large number of sets in which the molded body B of the rotor 13 is arranged in the hollow portion Ai of the annular molded body A of the outer case 19 are arranged on the sintering tray 100 and placed in the sintering furnace. As a result, the processing capacity of the sintering furnace can be utilized to the maximum, and a large number of sintered bodies of the outer case 19 and the rotor 13 can be sintered in a short time (the processing time can be substantially halved).

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments, 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 vane pump. FIG. 2 is a sectional view taken along line II-II in FIG. 3A and 3B show an annular molded body of the outer case, where FIG. 3A is a plan view and FIG. 3B is a cross-sectional view. 4A and 4B show a rotor compact, in which FIG. 4A is a plan view and FIG. 4B is a cross-sectional view. FIG. 5 is a plan view showing a state in which the rotor molded body is inserted into the hollow portion of the outer case annular molded body. FIG. 6 shows a mixed state of the molded body, (A) is a plan view, and (B) is a side view. FIG. 7 is an enlarged view of a main part of FIG. FIG. 8 is a plan view showing a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vane pump 11 Pump casing 12 Pump shaft 13 Rotor 19 Outer case 20 Fitting hole 22 Cam ring 23 Pump chamber 100 Tray A Ring molded body Ai Hollow part B Molded body

Claims (2)

The rotor fixed to the pump shaft supported by the pump casing, and the outer case that is fitted in the fitting hole of the pump casing and houses the cam ring that forms the pump chamber between the outer periphery of the rotor, are sintered. In the manufacturing method of the vane pump constituted by the body,
A method for manufacturing a vane pump, comprising: arranging a molded body of a rotor in a hollow portion of an annular molded body of an outer case in a sintering furnace, and sintering the molded body.   2. The method for manufacturing a vane pump according to claim 1, wherein a large number of sets in which a molded body of a rotor is arranged in a hollow portion of an annular molded body of the outer case is placed in a sintering tray and placed in a sintering furnace.

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