JP3803210B2 - Vane pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an improvement of a vane pump used for a power steering device of a vehicle.
[0002]
[Prior art]
Conventionally, a vane pump has been adopted as a pump for supplying hydraulic oil in a power steering device of a vehicle.
[0003]
In such a vane pump, as shown in FIG. 4, a drive shaft 8 coupled to a rotor 6 having a large number of vanes 11 is connected to a metal bearing 9 provided in the housing 1 and a metal bearing 10 ′ provided in the cover 7. A drive shaft 8 that is pivotally supported and protrudes from the housing 1 is connected to a power source. The metal bearing 9 pivotally supports the middle of the drive shaft 8, and the metal bearing 10 ′ pivotally supports the end of the drive shaft 8.
[0004]
The rotor 6 and the vane 11 rotate between the slidable contact surface of the cover 7 and the side plate 2 to suck and discharge hydraulic oil from a port (not shown).
[0005]
[Problems to be solved by the invention]
However, in the conventional vane pump, when the drive shaft 8 is connected to a drive source via a pulley or the like, a radial load acts on each of the metal bearings 9, 10 ′, and the vane pump becomes a high load and a high rotation. The radial load of the metal bearing 10 ′ on the cover 7 side shown in FIG. 4 is particularly large, and the heat generation of the metal bearing 10 ′ increases in accordance with the radial load.
[0006]
When the radial load and the heat generation increase, the cover 7 facing the rotor 6 and the vane 11 is deformed. In particular, when the sliding surface of the cover 7 near the drive shaft 8 is deformed toward the rotor 6 side, the rotor 6 and In some cases, seizure occurs between the covers 7 and the durability is lowered.
[0007]
Accordingly, the present invention has been made paying attention to such problems, and an object thereof is to prevent deformation of the cover sliding contact surface to prevent seizure of the rotor and to improve durability of the vane pump.
[0008]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a drive shaft coupled to a rotor having a plurality of vanes, a housing for accommodating the rotor and the vanes, a cover for closing the opening end surface of the housing with the rotor interposed therebetween, In the vane pump provided with a plurality of bearings that support the drive shaft on both sides of the rotor, the support hole for inserting the bearing provided in the cover is positioned between the cover sliding surface and the bearing. Thus, an annular recess having a diameter larger than that of the support hole is provided.
[0009]
Further, in the second invention , the support hole is formed in the cover sliding contact surface, and a large-diameter portion having a larger diameter than the support hole is formed, and the annular recess includes the large-diameter portion and the support hole. The diameter is larger than that of the large-diameter portion.
[0010]
[Action and effect of the invention]
In the first or second aspect of the invention, the end of the drive shaft is supported by a bearing inserted into the support hole of the cover, and when the load of the vane pump increases, a bearing on which a large radial load acts from the drive shaft is provided. The cover is deformed, and the cover sliding contact surface that is in sliding contact with the rotor tends to come into strong contact with the rotor.
[0011]
The annular recess can release the deformation of the cover sliding contact surface, and can prevent seizure between the cover sliding contact surface and the rotor, thereby improving the durability of the vane pump.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0013]
1 to 3 show an example in which the present invention is applied to a variable displacement vane pump.
[0014]
1 and 2, a side plate 2 and an adapter ring 3 are accommodated in a stacked state from the bottom surface (left side in FIG. 2) side in a substantially circular accommodation recess 1 a formed on the inner periphery of the housing 1. An annular cam ring 5 is supported on the inner side of the adapter ring 3 so as to be swingable to the left and right of a drive shaft 8 to be described later with the pin 4 as a pivot. A rotor 6 is accommodated inside the cam ring 5. The opening end of the housing recess 1a is sealed by the cover 7, and the side surfaces (side surfaces opposite to the side plate 2) of the adapter ring 3, the cam ring 5, and the rotor 6 are in contact with the cover 7 and sealed.
[0015]
As shown in FIG. 2, a through hole 1 b is formed in the bottom surface of the housing recess 1 a, and a drive shaft 8 is rotatably supported by the through hole 1 b through a metal bearing 9. Further, the front end side of the drive shaft 8 passes through the side plate 2 and the rotor 6 and reaches a support hole 7 a formed in the cover 7, and is rotatably supported by the support hole 7 a via the metal bearing 10. ing. The rotor 6 is spline-coupled to the drive shaft 8 and rotates integrally with the drive shaft 8. The drive shaft 8 is rotationally driven by a power engine (not shown).
[0016]
Further, as shown in FIG. 1, the vanes 11 are accommodated in the plurality of notches formed on the outer periphery of the rotor 6 so as to be able to protrude and retract in the radial direction of the rotor 6. Accordingly, when the rotor 6 is rotated by the rotation of the drive shaft 8, the tip of the vane 11 extending from the notch comes into contact with the inner peripheral surface of the cam ring 5, and a plurality of pump chambers 12 are interposed between the vanes 11. Is defined.
[0017]
The side plate 2 is formed with a kidney type high-pressure groove 13A and a low-pressure groove 14A. The high-pressure groove 13A and the low-pressure groove 14A are formed at symmetrical positions with the drive shaft 8 in between so as to face the pump chambers 12 on the discharge side and the suction side, respectively. The cover 7 is provided with a Kidney-type high-pressure groove 13B and a low-pressure groove 14B at positions facing the high-pressure groove 13A and the low-pressure groove 14A on the side plate 2 with the rotor 6 interposed therebetween. It faces the pump chamber 12 on the side and the suction side.
[0018]
The high-pressure groove 13 </ b> A communicates with a high-pressure chamber 16 formed at the bottom (most innermost portion) of the housing recess 1 a through a high-pressure passage 15 that penetrates the side plate 2. The high pressure chamber 16 communicates with the discharge port 18 via a variable orifice 25 as will be described later. Further, the low pressure concave groove 14 </ b> B communicates with the suction port 19 (and further the tank T) via the low pressure passage 17 formed in the cover 7.
[0019]
As described above, the cam ring 5 can swing to the left and right of the drive shaft 8 with the pin 4 as a pivot, and the cam ring 5 can take an eccentric position with respect to the drive shaft 8 as shown in FIG. As a result, when the rotor 6 rotates counterclockwise in FIG. 1 along with the rotation of the drive shaft 8, the volume of each pump chamber 12 changes with this rotation.
[0020]
Then, the hydraulic fluid from the suction port 19 is sucked into the pump chamber 12 on the suction side (low pressure concave grooves 14A and 14B side) that expands with this rotation, while the discharge side (high pressure concave grooves 13A and 13B) shrinks with this rotation. The hydraulic fluid is discharged from the pump chamber 12 on the side toward the discharge port 18.
[0021]
As shown in FIG. 1, a plug hole 1 c is formed in the side portion of the housing 1 so as to open into the accommodation recess 1 a (more specifically, open into a second fluid pressure chamber 31 described later). The plug hole 1c is closed when the plug 20 is attached in a screwed state.
[0022]
A cylinder hole 20a is opened at the distal end side of the plug 20 extending toward the accommodation recess 1a, and the control plunger 21 is slidably accommodated in the cylinder hole 20a.
[0023]
A feedback pin 61 penetrating the through hole 3a of the adapter ring 3 is disposed at the distal end of the control plunger 21, and the distal end of the control plunger 21 is brought into contact with the proximal end of the feedback pin 61. Comes into contact with the outer periphery of the cam ring 5.
[0024]
Further, the control plunger 21 is formed with a plunger hollow portion 21a that opens to the proximal end side.
[0025]
In this plunger hollow portion 21a, a spring 22 is interposed between the bottom surface of the cylinder hole 20a and the bottom surface of the plunger hollow portion 21a, and urges the control plunger 21 to the cam ring 5 side. The cam ring 5 is biased to its maximum discharge position via the feedback pin 61.
[0026]
A recess 20b is formed at a predetermined position on the outer periphery of the plug 20, and an annular fluid chamber 23 is formed in a region surrounded by the recess 20b and the plug hole 1c. In addition, a variable orifice 25 that opens through the side surface of the plug 20 and communicates with the outer peripheral side of the plug 20 and the cylinder hole 20a opens in the recess 20b. The hydraulic oil from the high pressure chamber 16 is introduced into the fluid chamber 23 through the fluid passage 36 formed in the housing 1, and further introduced into the cylinder hole 20 a and the plunger hollow portion 21 a through the variable orifice 25. An O-ring 24 is provided at the opening end of the plug hole 1c so that the fluid chamber 23 is securely sealed.
[0027]
The opening area of the variable orifice 25 is adjusted by the proximal end edge 21b of the control plunger 21 that slides in the cylinder hole 20a. In other words, the variable orifice 25 overlaps with the proximal edge 21b as the control plunger 21 is retracted into the cylinder hole 20a, and the opening area thereof is narrowed.
[0028]
A plurality of through holes 26 are formed on the side surface of the control plunger 21. The plunger hollow portion 21 a always communicates with a fluid chamber 27 formed between the housing recess 1 a of the housing 1 and the adapter ring 3 through these through holes 26. The fluid chamber 27 communicates with the discharge port 18 via the communication path 28. Thus, the plunger hollow portion 21 a is always in communication with the discharge port 18 via the through hole 26, the fluid chamber 27 and the communication passage 28.
[0029]
The outer diameter of the feedback pin 61 is made equal to the diameter of the through hole 3a with high fitting accuracy so that hydraulic fluid does not leak from between the feedback pin 61 and the through hole 3a. Thereby, the second fluid pressure chamber (second fluid pressure chamber) 31 is not directly communicated with the fluid chamber 27 (downstream of the variable orifice 25).
[0030]
Further, as shown in FIG. 2, the second fluid pressure chamber 31 communicates with the high pressure chamber 16 through a pressure introduction hole 62 that is a fixed orifice formed in the side plate 2.
[0031]
The pressure introducing hole 62 is provided independently of the fluid passage 36 connecting the high pressure chamber 16 and the variable orifice 25, and the second fluid pressure chamber 31 has a pressure (discharge pump) in the high pressure chamber 16. The pressure in the chamber 12) is introduced directly.
[0032]
Further, the second fluid pressure chamber 31 communicates with the annular port 64 of the control valve 40 via the communication path 63. The annular port 64 is opened and closed by the land portion 41a of the control valve 40, and is closed or communicated with the drain fluid chamber 46 according to the sliding position of the land portion 41a. In this case, a plurality of notches 65 are cut at the end of the land portion 41a on the drain fluid chamber 46 side, and the annular port 64 and the drain fluid chamber 46 communicate with each other while the flow rate is controlled through the opening of the notch 65. To do. The opening area of the notch 65 is gradually increased as the land portion 41a moves to the annular port 64 side.
[0033]
Thereby, the spring force of the spring 22 in the control plunger 21 acts on the cam ring 5 via the feedback pin 61, and the operation of the cam ring 5 is transmitted to the control plunger 21 via the feedback pin 61.
[0034]
The variable displacement vane pump is integrally provided with a control valve 40. The spool 41 of the control valve 40 is accommodated in a cylinder 42 formed in the housing 1 so as to be slidable from the base end side. The open end of the cylinder 42 is closed by a plug 43. A return spring 44 is interposed between the base end of the spool 41 and the bottom of the cylinder 42, and the spool 41 is urged toward the plug 43 by the return spring 44.
[0035]
The spool 41 includes a land portion 41a at the base end and a land portion 41b near the center in the axial direction. With these land portions 41a and 41b, the cylinder 42 has a low-pressure fluid chamber 45 between the bottom surface of the cylinder 42 and the land portion 41a (spool 41 base end), a drain fluid chamber 46 between the land portions 41a and 41b, A high pressure fluid chamber 47 between the land portion 41 b and the plug 43 is defined.
[0036]
The low pressure fluid chamber 45 communicates with the discharge port 18 downstream of the variable orifice 25 through an orifice 48 and a fluid pressure passage 49. The drain fluid chamber 46 is connected from the drain port 50 to the drain passage 57 in FIG. 2 and communicates with the tank T.
[0037]
The high pressure fluid chamber 47 is connected to the fluid pressure passage 58 and communicates with the high pressure chamber 16 via a fluid pressure passage 59 branched from the fluid passage 36.
[0038]
Furthermore, the drain fluid chamber 46 and the high pressure fluid chamber 47 are connected to each other through a fluid pressure passage 51 formed in the housing 1 and opened to the cylinder 42 and an orifice 52 formed in the adapter ring 3 according to the sliding position of the spool 41. The first fluid pressure chamber 32 communicates with the first fluid pressure chamber 32.
[0039]
Also, as shown in FIG. 3, an annular groove 53 that makes one round of the outer periphery of the land portion 41b is formed at the approximate center in the spool axis direction of the land portion 41b. Further, a slit 54 is cut out in the land portion 41b along the spool axial direction so that the annular groove 53 communicates with the drain fluid chamber 46.
[0040]
The annular groove 53 and the high-pressure fluid chamber 47 are sealed by a seal part 55 that is not cut out of the land part 41b. With such a configuration, at the initial stage of pump operation, the opening of the fluid pressure passage 51 communicates only with the drain fluid chamber 46 via the annular groove 53 and the slit 54. When the spool pressure (introduced pump chamber pressure) rises and the spool 41 (land portion 41b) moves rightward in the figure, the fluid pressure passage 51 starts to communicate with the high pressure fluid chamber 47. As a result, a flow of hydraulic oil is generated from the high pressure fluid chamber 47 to the drain fluid chamber 46 via the fluid pressure passage 51, and the pressure of the first fluid chamber 32 communicating with the fluid pressure passage 51 is the same as that of the high pressure fluid chamber 47. Meter-in control is performed in accordance with the opening degree with the fluid pressure passage 51.
[0041]
Here, as shown in FIG. 2, the pair of metal bearings 9 and 10 that support the drive shaft 8 with the rotor 6 interposed therebetween are arranged on the left side in the drawing in which the drive shaft 8 protrudes from the housing 1. The metal bearing 9 press-fitted into the shaft is supported in the middle of the drive shaft 8, while the metal bearing 10 press-fitted into the inner periphery of the support hole 7a formed in the cover 7 is the end of the drive shaft 8 on the right side in the figure. Is supported.
[0042]
In the support hole 7a of the cover 7, a large diameter portion 71 having a diameter larger than that of the support hole 7a is formed in a sliding contact surface 70 that is in sliding contact with the end surfaces of the rotor 6 and the vane 11. An annular recess 72 constituted by an annular groove having a diameter sufficiently larger than that of the large diameter portion 71 is formed between 71 and the support hole 7a.
[0043]
The metal bearing 10 is fitted into the support hole 7 a behind the annular recess 72.
[0044]
The distance from the sliding contact surface 70 to the annular recess 72 is set to, for example, about 2.5 mm.
[0045]
Therefore, when the pump load increases, the cover 7 provided with the metal bearing 10 is deformed by a large radial load acting on the drive shaft 8, and the sliding contact surface 70 near the drive shaft 8 tends to be displaced toward the rotor 6 side. .
[0046]
However, since the sliding contact surface 70 slidably contacting the rotor 6 and the vane 11 is separated from the bearing 10 by a predetermined amount and separated by the annular recess 72, the annular recess 72 absorbs deformation of the sliding contact surface 70. it can.
[0047]
Further, the deformation of the sliding contact surface 70 due to heat generation from the metal bearing 10 is the same as the deformation due to the radial load, and the sliding contact surface 70 close to the drive shaft 8 is directed toward the rotor 6 according to the radial load direction. In this case, the deformation of the sliding contact surface 70 can be absorbed by the annular recess 72.
[0048]
That is, the slidable contact surface 70 that is strongly in contact with the rotor 6 escapes to the annular recess 72 side, so that friction with the end surface of the rotor 6 is reduced and seizure occurs between the slidable contact surface 70 and the rotor 6. Can be prevented.
[0049]
The inner diameter of the large-diameter portion 71 opened in the sliding contact surface 70 is set to be larger than the outer diameter of the drive shaft 8 and ensures workability when the metal bearing 10 is press-fitted into the support hole 7a.
[0050]
Moreover, in the said embodiment, although the example which employ | adopted the metal bearings 9 and 10 as a bearing of the drive shaft 8 was shown, it is not limited to a metal bearing, It is sliding bearings, such as brass, bronze, and cast iron, Also good.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of the present invention.
FIG. 2 is a sectional view of the same.
FIG. 3 is a cross-sectional view showing a part of the control valve.
FIG. 4 is a cross-sectional view showing a conventional vane pump.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Housing 2 Side plate 6 Rotor 7 Cover 8 Drive shaft 9, 10 Metal bearing 11 Vane 12 Pump chamber 18 Discharge port 19 Suction port 70 Sliding contact surface 71 Large diameter part 72 Annular recess

Claims (2)

A drive shaft coupled to a rotor with a plurality of vanes;
A housing that houses the rotor and vanes;
A cover that closes the open end face of the housing across the rotor;
In a vane pump provided with a plurality of bearings that are respectively disposed on the housing and the cover and support the drive shaft on both sides of the rotor.
A vane pump characterized in that an annular recess having a diameter larger than that of the support hole is provided in a support hole into which the bearing provided in the cover is inserted, between the cover sliding contact surface and the bearing. In the support hole, an opening is formed on the cover sliding contact surface, and a large diameter portion larger than the support hole is formed,
2. The vane pump according to claim 1, wherein the annular recess is formed between the large diameter portion and the support hole and has a larger diameter than the large diameter portion .

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