JP2007146786A - Vane pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that muddy water resides in a support hole of a pump casing for a pump shaft in a vane pump. <P>SOLUTION: In the vane pump 10 having the pump shaft 1 supported in the support hole 15A of the pump casing 11 and having a pulley 80 fixed on a projection part 12A projecting outward from the support hole 15A of the pump shaft 12, an inner surface 92 of a hole opening part 91 facing an outside of the support hole 15A is formed in a taper shape expanding outward. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vane pump suitable for use in an automobile power steering device or the like.

As a vane pump, there is a vane pump in which a pump shaft is supported by a support hole of a pump casing, and a pulley is fixed to a protruding portion that protrudes outward from the support hole of the pump shaft, as described in Patent Document 1.
5-24983

  In the vane pump of Patent Document 1, when the pulley is fixed to the projecting portion of the pump shaft projecting from the support hole of the pump casing, a small gap is provided between the hole opening and the hole opening of the support hole of the pump casing. A draining portion for forming a water is provided in the pulley to prevent the muddy water from entering the support hole, and hence the bearing inside the pump casing.

  Even in the vane pump of Patent Document 1, it is not possible to completely prevent muddy water from entering the opening of the support hole. The muddy water that has once entered the hole opening stays in the support hole and eventually enters the bearings in the pump casing, which may cause rusting and mechanical damage of each part.

  An object of the present invention is to prevent muddy water from staying in a support hole of a pump casing for a pump shaft in a vane pump.

  The invention of claim 1 is a vane pump in which a pump shaft is supported in a support hole of a pump casing, and a pulley is fixed to a protruding portion protruding outward from the support hole of the pump shaft. The inner surface of the hole opening that faces is tapered so as to expand outward.

  The muddy water that has entered the hole opening of the support hole from between the pulley and the pump casing is discharged outward along the gradient of the tapered inner surface that expands outward from the hole opening. As a result, the muddy water does not stay in the support holes, and the muddy water does not enter the bearings or the like inside the pump casing, thereby causing no rust and mechanical damage in each part.

  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, and FIG. 3 is an enlarged cross-sectional view showing a support hole opening of a pump casing.

  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 (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 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 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.

  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.

  As shown in FIG. 2, the variable displacement 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.

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.

  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 is communicated with the oil chamber 51 of the pressurizing cylinder 50, and the piston 52 inserted into the oil chamber 51 is passed through the piston hole 53 provided in the adapter ring 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 adapter ring 19 is formed with a cam ring movement restricting stopper 19A in a protruding shape on 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 adapter ring 19 has a cam ring movement restricting stopper 19B protruding from 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 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 above-described cam ring movement restriction stopper 19A of the adapter ring 19 is provided. , 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) the pressure on the upstream side of the main throttle 58 will be described later in the first fluid pressure chamber 41 that gives the cam ring 22 movement displacement in a 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 which gives the cam ring 22 displacement in the direction that maximizes the volume of the pump chamber 23. The oil in the pressurizing cylinder 50 is introduced from the passage 28B via the branch communication passage 28D through the piston hole 53 of the adapter ring 19 and (3) the cam ring 22 is displaced in the direction in which the volume of the pump chamber 23 is maximized. 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, in cooperation with the throttle 61 </ b> A provided in FIG.

  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 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 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.

According to the present embodiment, the following operational effects can be obtained.
The muddy water that has entered the hole opening 91 of the support hole 15 </ b> A from between the pulley 80 and the pump casing 11 outwards along the gradient of the tapered inner peripheral surface 92 that expands toward the outside of the hole opening 91. Discharged. As a result, the muddy water does not stay in the support hole 15A, and the muddy water does not enter the bearing 16A or the like inside the pump casing 11, and neither rust is generated nor mechanical damage is caused in each part.

  In addition, when the pump 10 of FIG. 1 supports the pump shaft 12 in the support hole 15A of the pump casing 11 (pump housing 11A), the support hole 15A is provided with a bearing 16A, an oil seal 16D, and a bearing 16B in order from the outside. . However, in the present invention, even in the pump 10 in which the support hole 15A is provided with an oil seal and a bearing in order from the outside, the inner surface 92 of the hole opening 91 facing the outside of the support hole 15A is expanded outward. It can be tapered to open.

  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 vane pump. FIG. 2 is a sectional view taken along line II-II in FIG. FIG. 3 is an enlarged cross-sectional view of the support hole opening of the pump casing.

Explanation of symbols

10 Pump (vane pump)
11 Pump casing 12 Pump shaft 12A Protruding portion 15A Support hole 80 Pulley 91 Hole opening 92 Tapered inner surface

Claims (1)

In a vane pump that supports a pump shaft in a support hole of a pump casing and fixes a pulley to a protruding portion that protrudes outward from the support hole of the pump shaft.
A vane pump characterized in that an inner surface of a hole opening facing the outside of the support hole is tapered so as to expand outward.

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