JP2024134689A - Vane Pump - Google Patents

Abstract

[Problem] To stabilize the operation of a vane pump. [Solution] A vane pump 100 includes an insertion hole 15 formed in a housing 25 into which a drive shaft 1 is inserted so as not to penetrate the housing 25, a seal member 55 provided in a compressed state between the outer circumferential surface of the drive shaft 1 and the inner circumferential surface of the insertion hole 15, a suction passage 50 formed in the housing 25 and directing working fluid to a pump chamber 6 defined by a rotor 2, a cam ring 4, and a pair of adjacent vanes 3, an annular passage 18 communicating with the suction passage 50 and formed between the outer circumferential surface of the cam ring 4 and the inner circumferential surface of the housing 25, and a drain passage 57 communicating between the insertion hole 15 and the annular passage 18 and directing working fluid leaked into the insertion hole 15 to the annular passage 18. [Selected Figure] Figure 3

Description

The present invention relates to a vane pump.

Patent Document 1 discloses a pump device including a drive shaft, a pump element that is rotationally driven by the drive shaft, a pump housing that houses the pump element, and a seal member that seals between the drive shaft and the pump housing. The seal member is provided in a drive shaft housing hole that houses the drive shaft to seal between the drive shaft and the pump housing and prevent working fluid from leaking from the pump element to the outside of the pump housing. In addition, the drive shaft housing hole is provided with a return passage that communicates with a suction passage that supplies working fluid to the pump element. Working fluid that leaks from the pump element into the drive shaft housing hole is prevented from leaking outside the pump housing by the seal member, and is guided by the return passage to the suction passage and supplied to the pump element again.

JP 2019-44747 A

In a vane pump such as that described in Patent Document 1, for example, the pressure in the suction passage may increase due to the hydraulic fluid discharged from the pump element being returned to the suction passage. When the pressure in the suction passage becomes high, high pressure acts on the seal member through the return passage, causing a malfunction and possibly making the operation of the vane pump unstable.

The present invention was made in consideration of the above problems, and aims to stabilize the operation of the vane pump.

The present invention is a vane pump that includes a rotor that is connected to a drive shaft and driven to rotate, a plurality of vanes that are provided so as to be capable of reciprocating radially relative to the rotor, a cam ring having an inner cam surface against which the tips of the vanes slide as the rotor rotates, a housing that accommodates the cam ring, an insertion hole formed in the housing and into which the drive shaft is inserted so as not to penetrate the housing, a seal member that is provided in a compressed state between the outer circumferential surface of the drive shaft and the inner circumferential surface of the insertion hole, a suction passage formed in the housing that guides the working fluid to a pump chamber defined by the rotor, the cam ring, and a pair of adjacent vanes, an annular passage that communicates with the suction passage and is formed between the outer circumferential surface of the cam ring and the inner circumferential surface of the housing, and a drain passage that communicates with the insertion hole and the annular passage and guides the working fluid that has leaked into the insertion hole to the annular passage.

In this invention, the drain passage communicates with the suction passage through an annular passage formed between the outer peripheral surface of the cam ring and the inner peripheral surface of the housing. Therefore, even if the suction passage becomes high pressure, the pressure rise in the drain passage associated with the pressure rise in the suction passage is suppressed, and high pressure is prevented from acting on the sealing member, stabilizing the operation of the vane pump.

The present invention is also characterized in that the annular passage has a smaller flow cross-sectional area than the suction passage.

The present invention also provides a vane pump that further includes an axial passage that connects the annular passage and the drain passage and extends in the axial direction of the drive shaft, and the annular passage is disposed between the axial passage and the suction passage.

The present invention is also characterized in that the flow cross-sectional area of the annular passage is smaller than the flow cross-sectional area of the drain passage.

With these inventions, even if the pressure inside the suction passage becomes high, the pressure increase inside the drain passage that accompanies the pressure increase inside the suction passage is further suppressed, preventing high pressure from acting on the sealing member.

The present invention is also characterized in that the insertion hole is provided with a bushing that rotatably supports the drive shaft, and the drain passage communicates between the seal member in the insertion hole and the bushing.

In this invention, the working fluid that leaks into the insertion hole lubricates the sliding surfaces of the bush and drive shaft and is guided to the drain passage, stabilizing the operation of the vane pump.

According to the present invention, the operation of the vane pump is stable.

1 is a cross-sectional view of a vane pump according to an embodiment of the present invention. FIG. 2 is a plan view of the rotor, vanes, cam ring, and pump body with the pump cover and side plate removed. 3 is a cross-sectional view of the vane pump according to the embodiment of the present invention, taken along line III-III in FIG. 2.

Below, a vane pump 100 according to an embodiment of the present invention will be described with reference to the drawings. The vane pump 100 is used as a fluid pressure supply source for a fluid pressure device 70 (e.g., a power steering device, a transmission, etc.) mounted on a vehicle. Here, a fixed displacement vane pump 100 in which hydraulic oil is used as the working fluid will be described, but other fluids such as hydraulic water may be used as the working fluid, and the vane pump 100 may be a variable displacement type.

Figure 1 is a cross-sectional view of the vane pump 100, and Figure 2 is a plan view of the rotor 2, vanes 3, cam ring 4, and pump body 10 with the pump cover 20 and cover side plate 40 removed. Note that Figure 1 is a cross-section taken along line I-I in Figure 2.

1 and 2, the vane pump 100 includes a housing 25, a drive shaft 1 rotatably supported by the housing 25, an insertion hole 15 formed so as not to penetrate the housing 25 and into which the drive shaft 1 is inserted, a rotor 2 connected to the drive shaft 1 and driven to rotate, a plurality of slits 2s opening on the outer peripheral surface of the rotor 2, a plurality of vanes 3 slidably inserted into the slits 2s of the rotor 2 and provided so as to be capable of reciprocating radially relative to the rotor 2, and a cam ring 4 having an inner peripheral cam surface 4a against which the tip end 3a (see FIG. 2) of the vane 3 slides as the rotor 2 rotates. The housing 25 includes a pump body 10 having an accommodation recess 10A, and a pump cover 20 (see FIG. 1) that covers the accommodation recess 10A and is fixed to the pump body 10. The cam ring 4 accommodates the rotor 2 and the vanes 3.

The vane pump 100 is driven by a drive device (not shown), such as an engine or an electric motor. As shown in FIG. 1, an insertion hole 15 is formed in the housing 25, penetrating the pump cover 20 and extending without penetrating the pump body 10. The pump body 10 is formed with an accommodating recess 10A having a larger diameter than the insertion hole 15, which is continuous with the insertion hole 15. In the vane pump 100, the cam ring 4 accommodating the rotor 2 and vanes 3 is accommodated in the accommodating recess 10A of the pump body 10, and the drive shaft 1 is inserted into the insertion hole 15, so that the rotor 2 is connected to the drive shaft 1. The vane pump 100 generates fluid pressure by driving the rotor 2 to rotate counterclockwise as shown by the arrow in FIG. 2. The drive shaft 1 is rotatably supported by the housing 25 via bushes 11 and 12 provided in the insertion hole 15.

In the following, the direction along the rotation axis of the rotor 2 (in other words, the drive shaft 1) is referred to as the "axial direction", the radial direction centered on the rotation axis of the rotor 2 is referred to as the "radial direction", and the direction in which the rotor 2 rotates when the vane pump 100 is in operation is referred to as the "circumferential direction".

As shown in FIG. 1, the vane pump 100 further includes a body side plate 30 provided at one axial end of the rotor 2 and in contact with one side of the rotor 2 and the cam ring 4, and a cover side plate 40 provided at the other axial end of the rotor 2 and in contact with the other side of the rotor 2 and the cam ring 4.

The body-side side plate 30 is provided between the bottom surface of the accommodation recess 10A and the rotor 2. One axial end face of the rotor 2 (the lower end face in FIG. 1) slides against the body-side side plate 30, and one axial end face of the cam ring 4 (the lower end face in FIG. 1) abuts against it. The cover-side side plate 40 is provided between the rotor 2 and the pump cover 20. The other axial end face of the rotor 2 (the upper end face in FIG. 1) slides against the cover-side side plate 40, and the other axial end face of the cam ring 4 (the upper end face in FIG. 1) abuts against it.

In this way, the body side plate 30 and the cover side plate 40 are arranged facing both sides of the rotor 2 and the cam ring 4. In other words, the body side plate 30 and the cover side plate 40 are arranged so that they sandwich the rotor 2 and the cam ring 4 in the axial direction.

The body side plate 30, rotor 2, cam ring 4, and cover side plate 40 are accommodated in the accommodation recess 10A of the pump body 10. In this state, the accommodation recess 10A is sealed by attaching the pump cover 20 to the pump body 10.

As shown in FIG. 2, multiple slits 2s are formed radially in the rotor 2. The slits 2s open to the outer periphery of the rotor 2.

The vane 3 is formed in a rectangular flat plate shape. The vane 3 is slidably inserted into the slit 2s and has a tip end 3a which is the end protruding from the slit 2s and a base end 3b which is the end opposite the tip end 3a. Within the slit 2s, a back pressure chamber 5 is defined by the base end 3b of the vane 3. As described below, the back pressure chamber 5 communicates with the high pressure chamber 14, and hydraulic oil is introduced from the high pressure chamber 14 to the back pressure chamber 5. The vane 3 is pressed in the direction protruding from the slit 2s by the pressure of the hydraulic oil introduced into the back pressure chamber 5.

The cam ring 4 is an annular member having an inner cam surface 4a, which is an inner surface having a substantially elliptical shape. The inner cam surface 4a is the surface against which the tips 3a of the multiple vanes 3 slide as the rotor 2 rotates.

When the rotor 2 rotates, centrifugal force is generated in the vane 3. This centrifugal force presses the vane 3 in a direction in which it protrudes from the slit 2s. In other words, the vane 3 is pressed in a direction in which it protrudes from the slit 2s (radially outward) by the fluid pressure in the back pressure chamber 5 pressing the base end 3b and the centrifugal force acting as the rotor 2 rotates. When the vane 3 is pressed radially outward, the tip end 3a of the vane 3 slides against the inner cam surface 4a of the cam ring 4. As a result, a pump chamber 6 is defined inside the cam ring 4 by the outer circumferential surface of the rotor 2, the inner cam surface 4a of the cam ring 4, and a pair of adjacent vanes 3.

The inner cam surface 4a is formed in a roughly elliptical shape. Therefore, as the rotor 2 rotates, the volume of the pump chamber 6 repeatedly expands and contracts. Hydraulic oil is sucked in the expansion region (suction region) where the pump chamber 6 expands, and hydraulic oil is discharged in the contraction region (discharge region) where the pump chamber 6 contracts.

The cam ring 4 is formed with a diameter that is approximately the same as or smaller than the accommodating recess 10A of the pump body 10. The cam ring 4 has a pin hole 4b through which a positioning pin 8 is inserted, and is positioned relative to the housing 25 by inserting the positioning pin 8 into the pin hole 4b and a pin hole (not shown) of the pump cover 20. In this way, the positioning of the cam ring 4 is not performed by fitting it into the accommodating recess 10A of the pump body 10. Therefore, the vane pump 100 has an annular passage 18 as a clearance formed between the outer peripheral surface of the cam ring 4 and the inner peripheral surface of the pump body 10. In the vane pump 100 of this embodiment, the annular passage 18 is formed around the entire circumference in the circumferential direction.

As shown in FIG. 1, an annular high-pressure chamber 14 is defined by the pump body 10 and the body-side side plate 30 on the bottom side of the accommodation recess 10A of the pump body 10. The high-pressure chamber 14 is provided between the bottom surface of the accommodation recess 10A and the body-side side plate 30, and high-pressure hydraulic oil discharged from the pump chamber 6 is guided through the high-pressure chamber 14. The high-pressure chamber 14 is connected to a fluid pressure device 70 (e.g., a power steering device, a transmission, etc.) outside the vane pump 100 via a discharge passage 62.

A low pressure chamber 21 is formed in the pump cover 20, and a bypass passage 13 that communicates with the low pressure chamber 21 is formed on the inner circumferential surface of the accommodation recess 10A. As shown in FIG. 2, two bypass passages 13 are provided at positions facing each other across the cam ring 4. The low pressure chamber 21 is connected to the tank 60 via a tank passage 61. The low pressure chamber 21 and the bypass passage 13 form a suction passage 50 that guides hydraulic oil to the pump chamber 6, as described below. The suction passage 50 is formed in a partial circumferential area and communicates with the annular passage 18 (see FIG. 2).

As shown in FIG. 1, the discharge passage 62 is provided with a flow control valve 80 that controls the flow rate of the hydraulic oil supplied to the fluid pressure device 70. The flow control valve 80 can have a known configuration, so a detailed description is omitted. The flow control valve 80 returns a portion of the hydraulic oil supplied to the fluid pressure device 70 to the tank passage 61 through a return passage 81. In other words, the flow control valve 80 returns a portion of the hydraulic oil supplied to the fluid pressure device 70 to the suction side of the vane pump 100.

As shown in Figures 1 and 2, the body side plate 30 has a discharge port 31 (see Figure 2) formed to correspond to the discharge area, a through hole (not shown) through which the drive shaft 1 is inserted, a suction port 33 formed to correspond to the suction area, back pressure grooves 34 spaced apart from one another in the circumferential direction of the rotor 2 and communicating with the back pressure chamber 5, and a pin hole (not shown) through which the positioning pin 8 is inserted.

The discharge port 31 is formed through the body side plate 30 and guides the hydraulic oil discharged from the pump chamber 6 to the high pressure chamber 14. The suction port 33 is formed to have a concave shape that opens radially outward and guides the hydraulic oil from the bypass passage 13 of the suction passage 50 to the pump chamber 6. The back pressure groove 34 overlaps and communicates with multiple back pressure chambers 5 as the rotor 2 rotates. The back pressure groove 34 is formed through the body side plate 30 and communicates with the high pressure chamber 14. As a result, the high pressure hydraulic oil from the discharge port 31 is guided to the back pressure chamber 5 through the high pressure chamber 14 and the back pressure groove 34. The back pressure chamber 5 presses the vane 3 toward the inner cam surface 4a by the hydraulic oil guided through the back pressure groove 34, causing the vane 3 to slide against the inner cam surface 4a.

As shown in FIG. 1, the cover side plate 40 has a through hole (not shown) through which the drive shaft 1 passes, a suction port 43 formed to correspond to the suction area, and a pin hole (not shown) through which the positioning pin 8 passes.

The suction port 43 is formed through the cover side plate 40 and guides hydraulic oil from the low pressure chamber 21 of the suction passage 50 to the pump chamber 6. Thus, hydraulic oil is guided to the pump chamber 6 through the suction port 33 of the body side plate 30 and the suction port 43 of the cover side plate 40. The body side plate 30 and the cover side plate 40 are positioned relative to the housing 25 by the positioning pin 8, similar to the cam ring 4.

Here, in the vane pump 100, hydraulic oil may leak into the insertion hole 15 through the gap between the rotor 2 and the body side plate 30, or between the rotor 2 and the cover side plate 40, etc. For this reason, as shown in FIG. 3, the vane pump 100 is provided with a seal member 55 that prevents hydraulic oil leaked into the insertion hole 15 from leaking out of the housing 25. The seal member 55 is provided in a compressed state between the outer circumferential surface of the drive shaft 1 and the inner circumferential surface of the insertion hole 15. Specifically, the insertion hole 15 has a small diameter portion and a large diameter portion, and a seal member accommodating space 56 is formed by the large diameter portion. The seal member accommodating space 56 is a part of the insertion hole 15 and is formed in the pump cover 20. The seal member 55 is provided in the seal member accommodating space 56 to prevent hydraulic oil from leaking out of the housing 25.

As shown in FIG. 3, the vane pump 100 includes a drain passage 57 formed in the pump cover 20 that guides hydraulic oil leaked into the insertion hole 15 to the annular passage 18, a radial passage 58 formed in the pump cover 20 that communicates with the drain passage 57 and extends in the radial direction, and an axial passage 59 formed in the pump body 10 that communicates with the annular passage 18 and the drain passage 57 and extends in the axial direction.

The drain passage 57 is formed by extending linearly from the seal member accommodating space 56 to the radial passage 58. The drain passage 57 communicates between the seal member 55 and the bush 12 in the insertion hole 15 (seal member accommodating space 56). The radial passage 58 is formed by opening on the end face of the pump cover 20 and communicates the drain passage 57 with the axial passage 59. The axial passage 59 is formed by opening on the end face of the pump body 10 and communicates the radial passage 58 with the annular passage 18. The axial passage 59 is formed on the inner peripheral surface of the accommodating recess 10A and is formed so as to face the outer peripheral surfaces of the cam ring 4, the body side side plate 30, and the cover side side plate 40. The flow passage cross-sectional area of the radial passage 58 and the axial passage 59 is larger than the flow passage cross-sectional area of the drain passage 57. The radial passage 58 and the axial passage 59 have the function of connecting the annular passage 18 and the drain passage 57.

In this embodiment, the drain passage 57, the radial passage 58, and the axial passage 59 are formed one by one at a distance from the suction passage 50 in the circumferential direction (see FIG. 2). Therefore, the axial passage 59 does not directly communicate with the suction passage 50, but communicates with the suction passage 50 via the annular passage 18. Therefore, the hydraulic oil leaked into the insertion hole 15 is guided and returned to the suction passage 50 through the drain passage 57, the radial passage 58, the axial passage 59, and the annular passage 18. In other words, the drain passage 57, the radial passage 58, the axial passage 59, and the annular passage 18 function as connecting passages for communicating the insertion hole 15 and the suction passage 50. In this way, the drain passage 57 communicates with the insertion hole 15 and the annular passage 18.

The hydraulic oil leaking into the insertion hole 15 is returned to the suction passage 50, preventing hydraulic oil from accumulating in the insertion hole 15. This prevents the drive shaft 1 from being pushed up by the pressure of the hydraulic oil in the insertion hole 15, causing the rotor 2 to seize. The positions at which the drain passage 57, radial passage 58, and axial passage 59 are formed are not limited to the positions shown in FIG. 2, and it is sufficient that the axial passage 59 does not directly communicate with the suction passage 50.

In the vane pump 100 of this embodiment, as described above, the flow control valve 80 returns a portion of the hydraulic oil supplied to the fluid pressure device 70 to the tank passage 61. Therefore, if the flow rate of the hydraulic oil returning from the flow control valve 80 to the tank passage 61 increases, the pressure in the suction passage 50 may increase. If the vane pump 100 does not have an annular passage 18 and the drain passage 57 is directly connected to the suction passage 50, the pressure in the suction passage 50 becomes high due to the hydraulic oil returning from the flow control valve 80, and high pressure acts on the seal member 55 through the drain passage 57. This may cause problems such as damage or detachment of the seal member 55, which may cause the operation of the vane pump 100 to become unstable.

However, in the vane pump 100 of this embodiment, the drain passage 57 communicates with the suction passage 50 through the annular passage 18 formed between the outer peripheral surface of the cam ring 4 and the inner peripheral surface of the housing 25. The annular passage 18 has a small flow passage cross-sectional area because it is a clearance formed between the outer peripheral surface of the cam ring 4 and the inner peripheral surface of the housing 25. More specifically, the annular passage 18 has a smaller flow passage cross-sectional area than the suction passage 50. Therefore, even if the pressure in the suction passage 50 becomes high, a large pressure loss occurs in the annular passage 18, so that the pressure increase in the drain passage 57 due to the pressure increase in the suction passage 50 is suppressed. This prevents high pressure from acting on the seal member 55, stabilizing the operation of the vane pump 100.

In addition, in the vane pump 100, the annular passage 18 is provided between the axial passage 59 and the suction passage 50, and the flow path cross-sectional area of the annular passage 18 is smaller than the flow path cross-sectional area of the drain passage 57. This increases the pressure loss that occurs in the annular passage 18, and further suppresses the pressure increase in the drain passage 57 that accompanies the pressure increase in the suction passage 50. Note that the flow path cross-sectional area of the annular passage 18 may be larger than the flow path cross-sectional area of the drain passage 57, as long as the pressure increase in the drain passage 57 that accompanies the pressure increase in the suction passage 50 can be suppressed.

In addition, in the vane pump 100, the drain passage 57 communicates between the seal member 55 and the bush 12 in the insertion hole 15. Therefore, the hydraulic oil leaking into the insertion hole 15 lubricates the sliding surfaces of the bush 12 and the drive shaft 1 and is guided to the drain passage 57, so that the operation of the vane pump 100 is stable.

Next, the operation of the vane pump 100 will be described.

When the drive shaft 1 is rotated by the power of a drive device (not shown) such as an engine, the rotor 2 rotates in the direction shown by the arrow in FIG. 2. As the rotor 2 rotates, the pump chamber 6 located in the suction region expands. As a result, the hydraulic oil in the tank 60 is sucked into the pump chamber 6 through the tank passage 61, the suction passage 50, the suction port 33 of the body side plate 30, and the suction port 43 of the cover side plate 40, as shown in FIG. 1. Also, as the rotor 2 rotates, the pump chamber 6 located in the discharge region contracts. As a result, the hydraulic oil in the pump chamber 6 is discharged to the high pressure chamber 14 through the discharge port 31 (see FIG. 2). The hydraulic oil discharged to the high pressure chamber 14 is supplied to the external fluid pressure device 70 through the discharge passage 62. In the vane pump 100 of this embodiment, each pump chamber 6 repeats suction and discharge of hydraulic oil twice while the rotor 2 rotates once.

A portion of the hydraulic oil discharged into the high pressure chamber 14 is supplied to the back pressure chamber 5 through the back pressure groove 34, and presses the base end 3b of the vane 3 toward the inner cam surface 4a. Therefore, the vane 3 is pressed in a direction protruding from the slit 2s by the fluid pressure in the back pressure chamber 5 pressing the base end 3b and the centrifugal force acting with the rotation of the rotor 2. As a result, the tip end 3a of the vane 3 rotates while sliding against the inner cam surface 4a of the cam ring 4, so that the hydraulic oil in the pump chamber 6 is discharged from the discharge port 31 without leaking between the tip end 3a of the vane 3 and the inner cam surface 4a of the cam ring 4.

This embodiment provides the following advantages:

In the vane pump 100, the drain passage 57 communicates with the suction passage 50 through the annular passage 18 formed between the outer peripheral surface of the cam ring 4 and the inner peripheral surface of the housing 25. Therefore, even if the pressure inside the suction passage 50 becomes high, the pressure rise inside the drain passage 57 due to the pressure rise inside the suction passage 50 is suppressed, and high pressure is prevented from acting on the seal member 55, so the operation of the vane pump 100 is stable.

Next, modified examples of this embodiment will be described. The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, or to combine the configurations described in the different modified examples below.

<Modification 1>
In the above embodiment, the vane pump 100 includes the body side plate 30 and the cover side plate 40. However, the body side plate 30 and the cover side plate 40 are not essential components of the vane pump 100. Even with this configuration, the same effects as those of the above embodiment can be achieved.

<Modification 2>
In the above embodiment, the discharge passage 62 is provided with a flow control valve 80 for controlling the flow rate of the hydraulic oil supplied to the fluid pressure device 70, and the flow control valve 80 returns a part of the hydraulic oil supplied to the fluid pressure device 70 to the tank passage 61. However, the flow control valve 80 does not have to be provided in the discharge passage 62. Even if the flow control valve 80 is not provided, for example, when the fluid pressure device 70 has a configuration for controlling the flow rate of the hydraulic oil and returns a part of the hydraulic oil to the tank passage 61, the pressure in the suction passage 50 may become high. In the vane pump 100, even if the pressure in the suction passage 50 becomes high due to such a factor, the pressure increase in the drain passage 57 caused by the pressure increase in the suction passage 50 is suppressed, and high pressure is prevented from acting on the seal member 55, so that the operation of the vane pump 100 is stable.

<Modification 3>
In the above embodiment, the vane pump 100 includes the radial passage 58 communicating with the drain passage 57, and the axial passage 59 communicating with the radial passage 58 and the annular passage 18. However, the configuration of the passage communicating between the drain passage 57 and the annular passage 18 is not limited to the above. For example, the vane pump 100 may be configured not to include the radial passage 58 and the axial passage 59, and the drain passage 57 may directly communicate between the insertion hole 15 and the annular passage 18.

Furthermore, in the above embodiment, the drain passage 57, the radial passage 58, and the axial passage 59 are formed one by one, circumferentially away from the suction passage 50. However, this is not limited to this, and the drain passage 57, the radial passage 58, and the axial passage 59 may be formed in multiple numbers, as long as they are configured to communicate with the suction passage 50 via the annular passage 18.

<Modification 4>
In the above embodiment, the annular passage 18 is formed as a clearance between the outer circumferential surface of the cam ring 4 and the inner circumferential surface of the pump body 10 over the entire circumferential direction. However, the present invention is not limited to this, and the annular passage 18 may be formed only in a partial region in the circumferential direction as long as the annular passage 18 is configured to communicate with the suction passage 50.

The configuration, operation, and effects of the embodiment of the present invention are summarized below.

The vane pump 100 includes a rotor 2 connected to a drive shaft 1 and driven to rotate, a plurality of vanes 3 provided so as to be capable of reciprocating radially relative to the rotor 2, a cam ring 4 having an inner cam surface 4a against which the tip 3a of the vane 3 slides as the rotor 2 rotates, a housing 25 in which the cam ring 4 is accommodated, an insertion hole 15 formed in the housing 25 so as not to penetrate the housing 25 and into which the drive shaft 1 is inserted, a seal member 55 provided in a compressed state between the outer circumferential surface of the drive shaft 1 and the inner circumferential surface of the insertion hole 15, a suction passage 50 formed in the housing 25 and directing the working fluid to a pump chamber 6 defined by the rotor 2, the cam ring 4, and a pair of adjacent vanes 3, an annular passage 18 communicating with the suction passage 50 and formed between the outer circumferential surface of the cam ring 4 and the inner circumferential surface of the housing 25, and a drain passage 57 communicating between the insertion hole 15 and the annular passage 18 and directing the working fluid leaked into the insertion hole 15 to the annular passage 18.

In this configuration, the drain passage 57 communicates with the suction passage 50 through the annular passage 18 formed between the outer peripheral surface of the cam ring 4 and the inner peripheral surface of the housing 25. Therefore, even if the pressure inside the suction passage 50 becomes high, the pressure rise inside the drain passage 57 due to the pressure rise inside the suction passage 50 is suppressed, and high pressure is prevented from acting on the seal member 55, so the operation of the vane pump 100 is stable.

In addition, in the vane pump 100, the annular passage 18 has a smaller flow passage cross-sectional area than the suction passage 50.

The vane pump 100 further includes an axial passage 59 that connects the annular passage 18 and the drain passage 57 and extends in the axial direction of the drive shaft 1, and the annular passage 18 is provided between the axial passage 59 and the suction passage 50.

In addition, in the vane pump 100, the flow cross-sectional area of the annular passage 18 is smaller than the flow cross-sectional area of the drain passage 57.

With these configurations, even if the pressure inside the suction passage 50 becomes high, the pressure increase inside the drain passage 57 that accompanies the pressure increase inside the suction passage 50 is further suppressed, and high pressure is prevented from acting on the seal member 55.

In addition, in the vane pump 100, a bushing 12 that rotatably supports the drive shaft 1 is provided in the insertion hole 15, and the drain passage 57 communicates between the seal member 55 in the insertion hole 15 and the bushing 12.

In this configuration, the working fluid leaking into the insertion hole 15 lubricates the sliding surfaces of the bush 12 and the drive shaft 1 and is guided to the drain passage 57, stabilizing the operation of the vane pump 100.

Although the embodiments of the present invention have been described above, the above embodiments merely show some of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

1... drive shaft, 2... rotor, 3... vane, 3a... tip, 4... cam ring, 4a... inner cam surface, 6... pump chamber, 12... bush, 15... insertion hole, 18... annular passage, 25... housing, 50... suction passage, 55... seal member, 57... drain passage, 59... axial passage, 100... vane pump

Claims (5)

a rotor connected to a drive shaft and driven to rotate;
A plurality of vanes provided so as to be capable of reciprocating radially relative to the rotor;
a cam ring having an inner peripheral cam surface against which the tip of the vane slides as the rotor rotates;
a housing in which the cam ring is accommodated;
an insertion hole formed in the housing and into which the drive shaft is inserted so as not to penetrate the housing;
a seal member provided in a compressed state between an outer circumferential surface of the drive shaft and an inner circumferential surface of the insertion hole;
a suction passage formed in the housing for introducing working fluid into a pump chamber defined by the rotor, the cam ring, and a pair of adjacent vanes;
an annular passage formed between an outer peripheral surface of the cam ring and an inner peripheral surface of the housing, the annular passage communicating with the suction passage;
a drain passage that connects the insertion hole and the annular passage and guides working fluid leaked into the insertion hole to the annular passage. 2. The vane pump according to claim 1,
A vane pump, wherein the annular passage has a flow passage cross-sectional area smaller than that of the suction passage. 2. The vane pump according to claim 1,
an axial passage that communicates with the annular passage and the drain passage and extends in the axial direction of the drive shaft;
The vane pump, wherein the annular passage is provided between the axial passage and the suction passage. 2. The vane pump according to claim 1,
A vane pump, wherein a flow passage cross-sectional area of the annular passage is smaller than a flow passage cross-sectional area of the drain passage. 2. The vane pump according to claim 1,
A bush is provided in the insertion hole to rotatably support the drive shaft,
The drain passage communicates with a portion of the insertion hole between the seal member and the bush.

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