JP7121686B2 - vane pump - Google Patents

Description

The present invention relates to vane pumps.

Patent document 1 includes a rotor, a plurality of vanes slidably provided on the rotor, an annular cam ring surrounding the rotor and the plurality of vanes, and a connecting rod passing through a hole formed in the cam ring. A vane pump is disclosed. In a vane pump, a pump chamber is defined by a rotor, an inner peripheral surface of a cam ring, and adjacent vanes.

JP 2015-137567 A

In the vane pump, the pump chamber expands as the rotor rotates to suck in the working fluid, and the pump chamber contracts to pressurize and discharge the working fluid.

In such a vane pump, the pressure in the pump chamber, which is pressurized as the rotor rotates, may cause the cam ring to expand and deform, changing the shape of the inner peripheral surface of the cam ring. When the shape of the inner peripheral surface of the cam ring changes, the volumetric efficiency of the pump chamber changes, which may reduce the volumetric efficiency.

SUMMARY OF THE INVENTION An object of the present invention is to improve the volumetric efficiency of a vane pump.

The present invention relates to a vane pump, comprising a rotor connected to a drive shaft, a plurality of vanes provided to reciprocate in a radial direction with respect to the rotor, and vanes whose tips slide as the rotor rotates. A cam ring having a peripheral surface, a pump chamber defined by a rotor, a cam ring, and a pair of adjacent vanes, a pump body housing the rotor and the cam ring, and an insertion hole formed in the cam ring passing through the pump body. a pin member for positioning the cam ring, wherein the inner peripheral surface of the insertion hole has a flat surface that intersects an imaginary line connecting the center of the cam ring and the center of the insertion hole, and the flat surface is closer to the cam ring than the pin member. It is characterized by being provided radially inward.

According to the present invention, the through hole is not a perfectly circular hole, but has a flat surface that intersects an imaginary line connecting the center of the cam ring and the center of the through hole. Therefore, the clearance between the pin member and the insertion hole in the radial direction of the cam ring can be made smaller than when the insertion hole is circular, and the contact between the flat surface of the insertion hole and the pin member swells the cam ring. deformation is restricted.

Further, the present invention is characterized in that the flat surface is provided perpendicular to the imaginary line, and the inner peripheral surface of the insertion hole further has an opposing surface parallel to the flat surface provided so as to sandwich the pin member together with the flat surface. and

In this invention, the clearance between the through hole and the pin member in the radial direction of the cam ring is defined by the flat surface and the opposing surface that are planes parallel to each other. As a result, even if a force that causes the cam ring to bulge outward in the radial direction acts on the cam ring, the flat surface and the opposing surface that are perpendicular to this force come into contact with the pin member and receive the force. Therefore, deformation of the inner peripheral surface of the cam ring can be further suppressed.

ADVANTAGE OF THE INVENTION According to this invention, the volumetric efficiency of a vane pump improves.

FIG. 2 is a plan view of the vane pump according to the embodiment of the present invention, showing a state in which a pump cover and a second side plate are removed; FIG. 2 is a cross-sectional view of the vane pump according to the embodiment of the present invention, showing a cross section taken along line II-II of FIG. 1; FIG. 2 is a cross-sectional view of the vane pump according to the embodiment of the present invention, showing a cross section taken along line III-III of FIG. 1; FIG. 4 is an enlarged plan view showing a cam ring insertion hole and a positioning pin in the vane pump according to the embodiment of the present invention;

A vane pump 100 according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

The vane pump 100 is used as a hydraulic supply source for hydraulic equipment mounted on a vehicle, such as a power steering system and a transmission. The vane pump 100 is of a fixed displacement type that uses hydraulic oil as a working fluid.

In the vane pump 100, the power of an engine (not shown) or the like is transmitted to the end of the drive shaft 1, and the rotor 2 connected to the drive shaft 1 rotates. The rotor 2 rotates clockwise in FIG.

As shown in FIG. 1, the vane pump 100 accommodates a plurality of vanes 3 which are provided to freely reciprocate in the radial direction with respect to the rotor 2, and the rotor 2. As the rotor 2 rotates, the tips of the vanes 3 slide. The pump body 5 includes a cam ring 4 having a cam surface 4 a that is a moving inner peripheral surface, and a pump body 5 having a housing recess 5 a that houses the cam ring 4 .

The rotor 2 is formed with slits 7 that are open on the outer peripheral surface and are radially formed at predetermined intervals. The vane 3 is inserted into the slit 7 so as to reciprocate. A back pressure chamber 8 into which the discharge pressure is guided is defined in the slit 7 by the base end portion of the vane 3 . Adjacent back pressure chambers 8 are communicated with each other by back pressure grooves (not shown) formed in a pump cover 15, which will be described later.

The vane 3 is pushed in the direction of exiting from the slit 7 by the pressure of the hydraulic oil guided to the back pressure chamber 8 , and the tip portion contacts the cam surface 4 a of the cam ring 4 . Thereby, a plurality of pump chambers 6 are defined inside the cam ring 4 by the outer peripheral surface of the rotor 2 , the cam surface 4 a of the cam ring 4 , and the adjacent vanes 3 .

The cam ring 4 is an annular member with an inner peripheral cam surface 4a having a substantially oval shape. The cam ring 4 has a suction region 4 b that expands the volume of the pump chamber 6 and a discharge region 4 c that contracts the volume of the pump chamber 6 . Thus, each pump chamber 6 expands and contracts as the rotor 2 rotates. In this embodiment, the cam ring 4 has two suction areas 4b and two discharge areas 4c. A region between the suction region 4b and the discharge region 4c is a transition region 4d where the direction in which the vanes 3 move in the radial direction of the rotor 2 changes.

As shown in FIG. 2, the housing recess 5a of the pump body 5 contains the rotor 2, a first side plate 10 disposed in contact with one side surface of the cam ring 4 (lower side surface in FIG. 2), and the cam ring 4. A second side plate 12 arranged in contact with the other side surface (upper side surface in FIG. 2) is accommodated. That is, the first side plate 10, the cam ring 4, and the second side plate 12 are stacked and accommodated in the accommodation recess 5a in this order. In this manner, the first and second side plates 10 and 12 are arranged to sandwich both side surfaces of the rotor 2 and the cam ring 4 and seal the pump chamber 6 .

A pump cover 15 is arranged on the side of the second side plate 12 opposite to the cam ring 4 . The pump cover 15 is fastened to the pump body 5 with its end surface in contact with the annular end surface of the pump body 5 . Thus, the housing recess 5 a of the pump body 5 is sealed by the pump cover 15 .

The drive shaft 1 is rotatably supported by the pump body 5 via a bush 30 and rotatably supported by the pump cover 15 via a bush 31 at its end. The drive shaft 1 passes through the first and second side plates 10,12.

The first side plate 10 has two arcuate discharge ports 11a which open corresponding to the discharge region 4c (see FIG. 1) of the cam ring 4 and lead the hydraulic oil discharged from the pump chamber 6 to the high pressure chamber 20. 11b is formed through.

The end surface of the second side plate 12 on which the rotor 2 slides has openings corresponding to the two suction areas 4b (see FIG. 1) of the cam ring 4, and has an arcuate shape that guides the working oil as the working fluid to the pump chamber 6. are formed with two suction ports (not shown).

A suction passage 21 is formed in the pump body 5 and the pump cover 15 to communicate between a tank (not shown) and a suction port, and to guide hydraulic oil in the tank to the pump chamber 6 through the suction port. The pump body 5 is formed with a discharge passage (not shown) that communicates with the high pressure chamber 20 and supplies the working oil in the high pressure chamber 20 to external hydraulic equipment.

As shown in FIG. 3, the first side plate 10 is formed with two pin holes 10a. A positioning pin 40 as a pin member is coupled to each of the two pin holes 10a.

A pair of insertion holes 50 are formed in the cam ring 4 at positions corresponding to the two pin holes 10 a of the first side plate 10 . The pair of insertion holes 50 are provided at symmetrical positions with respect to the center of the cam ring 4 (see FIG. 1).

Similarly, the second side plate 12 and the pump cover 15 are formed with a pair of through holes 12a and a pair of pin holes 15a at positions corresponding to the two pin holes 10a of the first side plate 10, respectively.

The positioning pin 40 is a rod-shaped member having a perfect circular cross section. The positioning pin 40 is inserted through the through hole 50 of the cam ring 4 and the through hole 12 a of the second side plate 12 and into the pin hole 15 a of the pump cover 15 . The positioning pin 40 restricts relative rotation of the cam ring 4 with respect to the pump cover 15 and the first and second side plates 10 and 12 . Thereby, the cam ring 4 is positioned with respect to the pump body 5 by the positioning pin 40 .

As the rotor 2 rotates, the vane pump 100 sucks hydraulic oil from the tank through the suction port and the suction passage 21 into the pump chambers 6 in the suction region 4b of the cam ring 4, and also pumps the hydraulic oil into the pump chambers 6 in the discharge region 4c of the cam ring 4. Hydraulic oil is discharged to the outside through the discharge ports 11a and 11b and the discharge passage. In this manner, the vane pump 100 supplies and discharges hydraulic oil by expanding and contracting each pump chamber 6 as the rotor 2 rotates.

Next, the structures of the insertion hole 50 of the cam ring 4 and the positioning pin 40 will be described in detail. 4, the center O1 of the cam ring 4 and the center O2 of the insertion hole 50 will be described in a plan view of the cam ring 4 (states shown in FIGS. 1 and 4) viewed from the central axis direction of the cam ring 4. A virtual line L passing through is set and explained. In other words, the virtual line L is a line perpendicular to the central axis of the cam ring 4 and the central axis of the insertion hole 50 .

The pair of insertion holes 50 of the cam ring 4 are through holes that pass through the cam ring 4 along the axial direction of the cam ring 4 so as to overlap the transition region 4d, in other words, to be positioned within the range of the transition region 4d. formed (see FIG. 1). As shown in FIG. 4, the inner peripheral surface of the insertion hole 50 includes a flat surface 51 provided so as to perpendicularly intersect the virtual line L, and a flat surface 51 provided so as to sandwich the positioning pin 40 together with the flat surface 51. and parallel facing surfaces 52 . In other words, the flat surface 51 and the opposing surface 52 are a pair of flat surfaces formed parallel to the center axis of the insertion hole 50 and parallel to each other.

The flat surface 51 is provided so as to be located radially inside the cam ring 4 relative to the positioning pin 40 . The facing surface 52 is provided radially outside the positioning pin 40 .

The flat surface 51 and the opposing surface 52 are connected in the circumferential direction of the insertion hole 50 by a pair of arcuate surfaces 53 and 54 . The pair of arcuate surfaces 53 and 54 are arcuate surfaces centered on the center O2 of the insertion hole 50 and having the same radius of curvature. A distance D2 between the pair of arcuate surfaces 53 and 54, which corresponds to the diameter of the arcuate surfaces 53 and 54, is larger than the distance D1 between the flat surface 51 and the opposing surface 52. As shown in FIG.

Therefore, when the positioning pin 40 having a circular cross section is inserted through the insertion hole 50 of the cam ring 4, the clearance between the positioning pin 40 and the flat surface 51 and the opposing surface 52 is the same as that of the positioning pin 40 and the pair of arcuate surfaces 53 and 54. less than the clearance between That is, the insertion hole 50 has a smaller width in the radial direction of the cam ring 4 and a smaller clearance between the positioning pin 40 in the radial direction of the cam ring 4 than when the insertion hole 50 is formed as a perfect circular hole. configured to be

Here, the cam ring receives a force that expands radially outward due to the high pressure of the hydraulic oil in the pump chamber in the discharge region. When the cam ring expands radially outward, the shape of the cam surface changes, so the volume of the pump chamber formed by the cam surface and the vanes changes. When the cam surface changes so that the volume of the pump chamber in the discharge region increases, the change in the volume of the pump chamber when transitioning from the suction region to the discharge region becomes small, and the hydraulic oil discharged from the pump chamber in the discharge region decreases. There is a possibility that the discharge amount of the ink may decrease. If the shape of the cam surface changes in this way, there is a risk that the volumetric efficiency of the vane pump will decrease.

On the other hand, in the vane pump 100 according to this embodiment, even if the cam ring 4 tries to be deformed so as to swell in the radial direction due to the high pressure of the hydraulic oil in the pump chamber 6 in the discharge region 4c, the positioning pin 40 and the flat surface 51 are in contact with each other in the radial direction. Since the clearance between the positioning pin 40 and the flat surface 51 of the insertion hole 50 is smaller than when the insertion hole 50 is perfectly circular, the swelling deformation of the cam ring 4 is restricted and the cam surface 4a is deformed. is suppressed. Therefore, a decrease in the volumetric efficiency of the vane pump 100 can be suppressed.

Further, in the vane pump 100, the radial clearance between the positioning pin 40 and the insertion hole 50 is defined by the flat surface 51 and the opposing surface 52, and the distance D1 between the flat surface 51 and the opposing surface 52 is defined by the pair of arcuate surfaces. It is smaller than the interval D2 between 53 and 54. That is, in the insertion hole 50, the radial interval D1 of the cam ring is smaller than the circumferential interval (interval in the direction perpendicular to the interval D1) D2.

Thus, the vane pump 100 is configured such that the clearance between the positioning pin 40 and the insertion hole 50 is not uniformly reduced, but is reduced only in the radial direction of the cam ring 4 . Since the flat surface 51 and the opposing surface 52 are planes parallel to each other, they can be easily formed by machining with high processing accuracy. Therefore, in order to suppress the deformation of the cam ring 4, the flat surface 51 and the opposing surface 52 should be machined with high accuracy, and high machining accuracy is not required for other parts. Therefore, according to the vane pump 100, the accuracy of the flat surface 51 and the opposing surface 52 can be easily ensured, and the entire inner peripheral surface of the insertion hole 50 does not need to be machined with high machining accuracy. It is possible to suppress the increase and easily manage dimensions.

Next, a modified example of this embodiment will be described.

In the above embodiment, the flat surface 51 is provided perpendicular to the virtual line L. As shown in FIG. On the other hand, the flat surface 51 can be provided at any position as long as it restricts the deformation of the cam ring 4 such that it bulges in the radial direction. Specifically, the flat surface 51 need not be a plane parallel to the imaginary line L, and at least a portion of the flat surface 51 is located radially inside the center of the insertion hole 50 and intersects the imaginary line L (imaginary inclined with respect to the line L). According to this, even if the cam ring 4 tries to deform so as to expand, the flat surface 51 comes into contact with the positioning pin 40 in the radial direction, so deformation of the cam ring 4 can be suppressed.

Further, in the above embodiment, the insertion hole 50 has the opposing surface 52 parallel to the flat surface 51 . On the other hand, in order to suppress the deformation of the cam ring 4, the insertion hole 50 should have at least the flat surface 51, and the opposing surface 52 is not essential.

According to the above embodiment, the following operational effects are obtained.

In the vane pump 100 , even if the cam ring 4 tries to expand radially due to the pressure of the hydraulic oil in the pump chamber 6 , the positioning pin 40 and the flat surface 51 come into contact with each other in the radial direction. Therefore, deformation of the cam surface 4a is suppressed as compared with the case where the insertion hole 50 is a perfect circle, so that a decrease in the volumetric efficiency of the vane pump 100 can be suppressed.

Further, in the vane pump 100 , the flat surface 51 is provided perpendicular to the virtual line L, and the inner peripheral surface of the insertion hole 50 is provided with a facing surface 52 parallel to the flat surface 51 . Thereby, the clearance between the insertion hole 50 and the positioning pin 40 in the radial direction of the cam ring 4 is defined by the flat surface 51 and the opposing surface 52 that are planes parallel to each other. Therefore, even if a force that deforms the cam ring 4 so as to expand radially outward acts on the cam ring 4, the flat surface 51 and the opposing surface 52 perpendicular to this force come into contact with the positioning pin 40 and receive the force. Therefore, deformation of the cam surface 4a of the cam ring 4 can be further suppressed, and a decrease in volumetric efficiency of the vane pump 100 can be suppressed.

Configurations, functions, and effects of embodiments of the present invention will be collectively described below.

The vane pump 100 includes a rotor 2 connected to a drive shaft 1, a plurality of vanes 3 provided to reciprocate in a radial direction with respect to the rotor 2, and tips of the vanes 3 sliding as the rotor 2 rotates. A cam ring 4 having a cam surface 4a, a pump chamber 6 defined by the rotor 2, the cam ring 4, and a pair of adjacent vanes 3, a pump body 5 accommodating the rotor 2 and the cam ring 4, and the cam ring 4. and a positioning pin 40 that passes through the insertion hole 50 and positions the cam ring 4 with respect to the pump body 5 . The flat surface 51 is provided radially inward of the cam ring 4 relative to the positioning pin 40 .

In this configuration, the insertion hole 50 is not a perfectly circular hole, but has a flat surface 51 that intersects an imaginary line L connecting the center of the cam ring 4 and the center of the insertion hole 50 . Therefore, compared with the case where the insertion hole 50 is circular, the clearance between the positioning pin 40 and the insertion hole 50 in the radial direction of the cam ring 4 can be reduced. The contact restricts deformation such as swelling of the cam ring 4 . Therefore, the volumetric efficiency of the vane pump 100 is improved.

Further, in the vane pump 100, the flat surface 51 is provided perpendicular to the imaginary line L, and the inner peripheral surface of the insertion hole 50 is provided so as to sandwich the positioning pin 40 together with the flat surface 51 and is parallel to the flat surface 51. 52 further.

In this configuration, the clearance between the insertion hole 50 and the positioning pin 40 in the radial direction of the cam ring 4 is defined by the flat surface 51 and the opposing surface 52 that are planes parallel to each other. Thereby, the clearance between the insertion hole 50 and the positioning pin 40 in the radial direction of the cam ring 4 is defined by the flat surface 51 and the opposing surface 52 that are planes parallel to each other. Therefore, even if a force that deforms the cam ring 4 so as to expand radially outward acts on the cam ring 4, the flat surface 51 and the opposing surface 52 perpendicular to this force come into contact with the positioning pin 40 and receive the force. Deformation of the cam surface 4a of the cam ring 4 can be further suppressed. Therefore, a decrease in the volumetric efficiency of the vane pump 100 can be suppressed.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

DESCRIPTION OF SYMBOLS 1... Drive shaft 2... Rotor 3... Vane 4... Cam ring 4a... Cam surface (inner peripheral surface) 5... Pump body 6... Pump chamber 40... Positioning pin (pin member) 50... Insertion hole , 51... flat surface, 52... facing surface, 100... vane pump

Claims (2)

a rotor coupled to the drive shaft;
a plurality of vanes provided so as to reciprocate in a radial direction with respect to the rotor;
a cam ring having an inner peripheral surface on which tips of the vanes slide as the rotor rotates;
a pump chamber defined by the rotor, the cam ring, and a pair of adjacent vanes;
a pump body that houses the rotor and the cam ring;
a pin member that passes through an insertion hole formed in the cam ring and positions the cam ring with respect to the pump body;
an inner peripheral surface of the insertion hole has a flat surface that intersects an imaginary line passing through the center of the cam ring and the center of the insertion hole;
The vane pump, wherein the flat surface is provided radially inward of the cam ring relative to the pin member. The flat surface is provided perpendicular to the virtual line,
2. The vane pump according to claim 1, wherein the inner peripheral surface of said insertion hole further has a facing surface parallel to said flat surface provided so as to sandwich said pin member together with said flat surface.

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