CN102444578B - Variable displacement vane pump - Google Patents

Abstract

Disclosed is a variable capacity vane pump that does not have a release pressure instability of a safety valve and suppresses noise when the safety valve is opened. The seat surface (45) on which the ball valve (35) fits when the safety valve (33) is closed is formed so that the center C of the ball valve (35) is radially directed relative to the axis (A1) of the valve hole (34). Offset to one side. Thus, the pressure (F) of the safety valve spring (37) forcibly presses the ball valve (35) to the wide portion (45b) on the radial side of the valve seat surface (45), even when the valve is opened. By bringing the ball valve (35) into contact with the wide portion (45b) of the valve seat surface (45), vibration of the ball valve (35) can be suppressed.

Description

Variable capacity vane pump

technical field

The present invention relates to, for example, a variable capacity vane pump suitable for use in hydraulic power steering devices of motor vehicles.

Background technique

Conventionally, it is known that a variable displacement vane pump is provided with a safety valve for protecting hydraulic equipment from excessive pressure rise. In this safety valve, the spherical valve body held by the valve body holding member is pressed against the valve seat member by a coil spring. However, when the safety valve is opened, the valve body and the valve body holding member vibrate, causing noise.

Then, in the technology described in Patent Document 1, the ball valve seat as the valve body holding member is inclined, and the ball valve seat and the valve body are formed by contacting the outer peripheral portion of the ball valve seat with the outer peripheral surface of the valve hole that houses the ball valve seat. Friction is generated between the outer peripheral surfaces of the holes to suppress noise.

Patent Document 1: Japanese Unexamined Patent Publication No. 2003-74725

However, in the technology described in Patent Document 1, the frictional force generated between the ball valve seat and the outer peripheral surface of the valve hole is limited due to dimensional errors, assembly errors, and hydraulic pressure acting on the valve body. Deviation, there is a problem that the safety pressure of the safety valve opening is unstable.

Contents of the invention

The present invention has been made in view of this problem, and an object of the present invention is to provide a variable displacement vane pump that stabilizes the relief pressure and suppresses noise generated when the relief valve is opened.

The variable capacity vane pump of the present invention includes: a rotor disposed in a housing space in the pump main body, and having a plurality of vanes provided radially freely, and the rotor is driven to rotate by a drive shaft;

a cam ring disposed on the outer peripheral side of the rotor so as to be movable in a direction in which an eccentric amount of the rotor changes, forming a plurality of pump chambers together with the vanes and the rotor; and a suction passage connected to the accommodation space. The suction area in which the volume of each of the pump chambers increases with the rotation of the rotor communicates with the discharge passage, which communicates with the volume of each of the pump chambers in the storage space that decreases with the rotation of the rotor. The discharge area is connected; a pressure control mechanism, which controls the pressure of at least one of a pair of fluid pressure chambers formed on both radial sides of the cam ring, so as to control the eccentricity of the cam ring relative to the rotor; safety a valve provided in the pump main body to open and close the oil passage between the discharge passage and the suction passage; the variable displacement vane pump is characterized in that the safety valve has a valve hole, which provided in the pump main body; a ball valve-shaped valve body disposed in the valve hole; a valve seat member fixed on one side in the axial direction through the valve body in the valve hole, and A through hole communicating with the discharge passage is formed, and an annular valve seat surface fitted (seated) with the valve body when the valve is closed is formed on the valve body side opening of the through hole; The valve hole is set on the other side across the valve body; the valve body holding part is set between the valve body and the coil spring, and a limit is formed on the valve body side The relative displacement of the body in the radial direction also holds the valve body holding part of the valve body, and a spring engaging part that limits its relative displacement in the radial direction relative to the coil spring is formed on the side of the coil spring. The restoring force generated by the compression deformation of the coil spring presses the valve body to the side of the valve seat part; The axial center of the end ring portion (seat roll portion) on the opposite side to the valve seat surface is offset in the radial direction.

Specifically, the inventions of the first and second aspects of the present invention are characterized in that, in the valve seat member, the valve seat surface that fits the valve body when the valve is closed is formed so that the valve seat surface when the valve is closed The center of the valve body is radially biased relative to the axis of the end ring portion on the opposite side of the valve seat surface in the coil spring.

The invention according to the third aspect of the present invention is characterized in that, among the valve body holding members, the valve body holding portion holding the valve body is formed to hold the Therefore, when the valve is closed, the valve body retaining portion is radially biased relative to the end ring portion of the coil spring opposite to the valve seat surface.

The invention according to the fourth aspect of the present invention is characterized in that the fitting surface of the coil spring on the opposite side to the valve body holding member is formed to be inclined with respect to an imaginary plane perpendicular to the axis center of the coil spring, whereby the The axis of the valve body holding part is inclined relative to the axis of the valve hole.

The invention of the fifth aspect of the present invention is characterized in that the valve seat surface is formed so that when the valve body is fitted to the valve seat surface to close the valve, the center of the valve body is open to the valve seat member. The axial center of the valve body-side end facing the valve body in the hole is offset.

According to the present invention, since part of the valve body abuts against the valve seat surface even when the valve is opened, vibration of the valve body can be suppressed, so that the relief pressure is stabilized and noise is prevented when the valve is opened.

Description of drawings

1 is an axial sectional view showing a variable displacement vane pump as a first embodiment of the present invention;

Fig. 2 is A-A sectional view of Fig. 1;

Fig. 3 is an enlarged view of the safety valve shown in Fig. 2;

Fig. 4 is an enlarged view showing details of the valve seat surface shown in Fig. 3;

Fig. 5 is a diagram showing a state in which the ball valve is fitted to the seat surface shown in Fig. 4;

Fig. 6 is an explanatory diagram showing the action of the ball valve when the safety valve shown in Fig. 3 is opened;

FIG. 7 is a diagram showing a modified example of the first embodiment;

Fig. 8 is a sectional view showing a safety valve as a second embodiment of the present invention;

Fig. 9 is an enlarged view of main parts of the safety valve shown in Fig. 8;

Fig. 10 is a diagram showing the action of the ball valve when the safety valve shown in Fig. 9 is opened;

Fig. 11 is a sectional view showing a safety valve as a third embodiment of the present invention;

Fig. 12 is an enlarged cross-sectional view showing the retainer shown in Fig. 8 alone;

Fig. 13 is a diagram showing a retainer alone as a modified example of the third embodiment;

Fig. 14 is a sectional view showing a safety valve as a fourth embodiment of the present invention;

Fig. 15 is a diagram showing the safety valve spring of the safety valve shown in Fig. 14 alone;

Fig. 16 is a view showing an open state of the safety valve shown in Fig. 14 .

Explanation of reference signs

1 Variable displacement vane pump 4 Pump body 4a Storage space 6 Drive shaft

7 rotor 8 cam ring 14a first fluid pressure chamber 14b second fluid pressure chamber

16 vane 17 pump chamber 19 suction passage 26 control valve (pressure control mechanism)

33 safety valve 34 valve hole 35 ball valve 36 seat parts

37 safety valve spring (coil spring) 37a first end ring part

37b second end ring portion 38 retainer (valve body holding member)

39 shaft part (spring engaging part) 40 ball valve holding part (valve body holding part)

44 through hole 45 seat surface 46 ball valve (valve body) 47 ball valve (valve body)

48 safety valve 49 valve seat part 50 valve seat surface

51 Retainer (valve body holding part) 52 Ball valve holding part (valve body holding part)

54 shaft part (spring engagement part)

A1 The axis of the valve hole (the axis of the first end ring)

The center of the C ball valve (the center of the valve body)

detailed description

1 and 2 are diagrams showing a variable capacity vane pump suitable for a vehicle hydraulic power steering system as a suitable embodiment of the present invention. FIG. 1 is an axial sectional view thereof, and FIG.

As shown in Fig. 1 and Fig. 2, in the variable capacity vane pump 1, the pump element 5 is accommodated in the accommodation space 4a in the pump main body 4, the pump main body 4 is formed by butting the front main body 2 and the rear main body 3, and utilizes The drive shaft 6 passing through the receiving space 4a drives the pump element 5 to rotate to realize the function of the pump.

The pump element 5 mainly includes: a rotor 7, which is connected to the drive shaft 6 and driven to rotate by the drive shaft 6; The direction in which the eccentricity of the rotor 7 changes is freely swingable; the bushing ring 9 is substantially circular, and accommodates the cam ring 8 on the inner peripheral side and is fitted in the outer peripheral cylinder of the housing space 4a. Surface: The pressure plate 10 is substantially disk-shaped and is disposed on the inner bottom surface 2a of the front main body 2 in the storage space 4a.

The bushing ring 9 and the pressure plate 10 are respectively positioned in the rotational direction with respect to the pump main body 4 by positioning pins 11 . In Fig. 2, a plate member 12 is provided on the clockwise side of the positioning pin 11, that is, on the side of the first fluid pressure chamber 14a described later. The function of the sealing member that seals between the ring 8 and the bushing ring 9 .

On the inner peripheral surface of the bushing ring 9, a sealing member 13 for sealing between the bushing ring 9 and the cam ring 8 is provided at a position opposite to the plate member 12 in the radial direction. A pair of fluid pressure chambers 14a, 14b are isolated between the cam ring 8 and the bushing ring 9 . That is, a first fluid pressure chamber 14a and a second fluid pressure chamber 14b are respectively formed on both radial sides of the cam ring 8, and the pressure difference between the two fluid pressure chambers 14a, 14b is used to make the cam ring 8 swing, so that the cam ring 8 relative to the increase or decrease of the eccentricity of the rotor 7. In addition, the cam ring 8 is constantly pressed by the return spring 15 in the direction in which the amount of eccentricity with respect to the rotor 7 is the largest.

A plurality of long slots 7 a cut in the radial direction are provided at equal intervals in the circumferential direction on the outer peripheral portion of the rotor 7 . The roughly flat blades 16 are respectively accommodated in the long grooves 7a freely in the radial direction of the rotor 7, and the annular space between the cam ring 8 and the rotor 7 is separated in the circumferential direction by these blades 16. A plurality of pump chambers 17 are formed. The rotor 7 is driven to rotate in the counterclockwise direction in FIG. 2 by the drive shaft 6 , whereby each pump chamber 17 rotates while increasing or decreasing its volume to perform a pumping operation. Each vane 16 is pressed against the inner peripheral surface of the cam ring 8 by the pressure of hydraulic oil introduced into the back pressure chamber 7b formed on the inner peripheral side of each long groove 7a.

In the rear main body 3, facing the inner surface 3a of the housing space 4a, and corresponding to the suction region where the volume of each pump chamber 17 gradually expands with the rotation of the rotor 7, a substantially crescent in the circumferential direction is cut out. Shaped first suction port 18. The first suction port 18 communicates with a suction passage 19 a provided in the rear body 3 . As a result, the hydraulic fluid introduced into the suction passage 19a via the suction pipe 20 connected to the oil tank not shown is sucked into the respective pump chambers 17 by the pump suction action in the suction region.

A second suction port 21 having substantially the same shape as the first suction port 18 is cut out on the surface of the pressure plate 10 facing the rotor 7 and at a position facing the first suction port 18 . The second suction port 21 communicates with a circulation passage 22 formed in the front body 2 . This circulation passage 22 communicates with a recess in the front main body 2, and the recess accommodates a sealing member sealing between the front main body 2 and the drive shaft 6, and the remaining oil of the sealing member is pumped to each due to the pump suction action of the above-mentioned suction area. The pump chamber 17 is supplied, thereby preventing the excess oil from leaking to the outside.

On the surface of the pressure plate 10 facing the rotor 7 and corresponding to the discharge area where the volume of each pump chamber 17 gradually decreases with the rotation of the rotor 7, a substantially crescent shape is cut out and formed in the circumferential direction when viewed from the front. The first discharge port 23. The first discharge port 23 communicates with the discharge passage 19 b via a pressure chamber 24 recessed from the inner bottom surface 2 a facing the pressure plate 10 in the front body 2 . As a result, the hydraulic oil discharged from each pump chamber 17 is discharged to the outside of the pump main body 4 through the pressure chamber 24 and the discharge passage 19 b by the pump discharge action in the discharge region, and is supplied to the hydraulic power hydraulic pressure of the power steering system (not shown). Cylinder sent. The pressure plate 10 is pressed toward the rotor 7 by the pressure in the pressure chamber 24 .

A second discharge port 25 having substantially the same shape as the first discharge port 23 is cut out at a position facing the first discharge port 23 on the inner surface 3 a of the rear body 3 . In this way, the first and second suction ports 18, 21 and the first and second discharge ports 23, 25 are arranged to be axially symmetrical across the pump chambers 17, so that the pump chambers 17 can be kept axially symmetrical. side pressure balance.

Inside the upper end side of the front body 2, a control valve 26 as a pressure control means for controlling the pump discharge pressure is provided in a direction perpendicular to the drive shaft 6 (left and right directions in FIG. 2). The control valve 26 is arranged on the front main body 2 from the left side to the right side in FIG. A substantially bottomed cylindrical sleeve 29 in the valve hole 28 and a control valve spring 30 press the sleeve 29 toward the plug 27 side.

The inside of the valve hole 28 is separated by the sleeve 29 into a high-pressure chamber 28a, which is formed between the plug 27 and the sleeve 29, and connects the discharge channel 19b formed in the discharge passage 19b. The upstream side hydraulic pressure is the hydraulic pressure introduction of the pressure chamber 24; the medium pressure chamber 28b accommodates the control valve spring 30 and introduces the downstream side hydraulic pressure of the flow measuring port; the low pressure chamber 28c is formed on the outer peripheral side of the sleeve 29, The pump suction pressure is introduced from the suction passage 19 a via the low-pressure passage 31 . The sleeve 29 moves in the axial direction based on the pressure difference between the medium pressure chamber 28b and the high pressure chamber 28a.

Specifically, when the pressure difference between the medium pressure chamber 28b and the high pressure chamber 28a is relatively small and the sleeve 29 is located on the side of the plug 27, the communication path 32 connecting the first fluid pressure chamber 14a and the valve hole 28 opens to the low pressure chamber 28c, The relatively low hydraulic pressure in the low-pressure chamber 28c is introduced into the first fluid pressure chamber 14a. On the other hand, when the pressure difference between the middle pressure chamber 28b and the high pressure chamber 28a increases and the sleeve 29 moves axially against the pressure of the control valve spring 30, the communication between the low pressure chamber 28c and the first fluid pressure chamber 14a is gradually reduced. The high pressure chamber 28a communicates with the first fluid pressure chamber 14a via the communication passage 32. Accordingly, relatively high hydraulic pressure in the high-pressure chamber 28a is introduced into the first fluid pressure chamber 14a. That is, the hydraulic pressure in the low-pressure chamber 28c or the high-pressure chamber 28a can be selectively introduced into the first fluid pressure chamber 14a.

And, when the pump suction pressure is always introduced into the second fluid pressure chamber 14b, and the hydraulic pressure of the low-pressure chamber 28c is introduced into the first fluid pressure chamber 14a, the cam ring 8 is located at the largest eccentricity with respect to the rotor 7 due to the pressing force of the return spring 15. The position (the left position in Figure 2), the pump discharge is the largest. On the other hand, when the hydraulic pressure of the high-pressure chamber 28a is introduced into the first fluid pressure chamber 14a, the pressure of the first fluid pressure chamber 14a causes the cam ring 8 to swing against the pressure of the return spring 15, so that the second fluid pressure chamber The volume of 14b becomes smaller, the amount of eccentricity between the cam ring 8 and the rotor 7 decreases, and the discharge amount of the pump decreases.

A safety valve 33 is formed inside the sleeve 29 . The relief valve 33 performs a release operation when the pressure in the intermediate pressure chamber 28b becomes higher than a predetermined pressure, that is, when the pressure on the power steering device side (load side) becomes higher than a predetermined pressure, and the hydraulic oil is released to the The suction passage 19a also flows. In other words, the oil passage between the discharge passage 19b and the suction passage 19a can be opened and closed by the safety valve 33 .

FIG. 3 is an enlarged view showing details of the safety valve 33 .

As shown in FIG. 3 , the safety valve 33 is provided with: a valve hole 34 formed on the inner peripheral side of the sleeve 29 and having a substantially cylindrical shape; 34 communicates with the low-pressure chamber 28c; the ball valve 35 as a spherical valve body is arranged in the valve hole 34; the valve seat part 36 is embedded and fixed on the axial side through the ball valve 35 in the valve hole 34; The valve spring 37, which is a coil spring, is provided on the other side in a compressed and deformed state across the ball valve 35 in the valve hole 34; the retainer 38 as a valve body holding member is provided between the ball valve 35 and the safety valve spring. 37, the ball valve 35 is pressed against the valve seat member 36 side by the restoring force of the compression deformation of the safety valve spring 37.

The retainer 38 includes: a shaft portion 39 as a spring engaging portion inserted into the inner peripheral side of the safety valve spring 37; and a ball valve holding portion 40 as a valve body holding portion formed on the shaft portion in an enlarged diameter shape. The end portion 39 on the valve seat member 36 side is fitted into the second end ring portion 37 b of the safety valve spring 37 on the valve seat member 36 side.

The shaft portion 39 is formed in a tapered shape gradually expanding in diameter toward the ball valve holding portion 40 side, and the outer peripheral surface of the base of the shaft portion 39 connected to the ball valve holding portion 40 is in contact with the second end ring portion 37b of the safety valve spring 37, Relative displacement in the radial direction between the second end ring portion 37b and the retainer 38 is restricted.

Regarding the ball valve holding portion 40, in the ball valve holding portion 40, a ball valve holding recess 41 as a valve body holding recess is recessed on the end surface of the ball valve holding portion 40 opposite to the shaft portion 39 to hold the ball valve 35. The stepped portion 42 between the shaft portions 39 is fitted to the second end ring portion 37 b of the safety valve spring 37 . The ball valve holding recess 41 is formed in a substantially flat mortar shape with rotational symmetry around the axis A2 of the retainer 38 , and by fitting the ball valve 35 into the ball valve holding recess 41 , the radial direction between the ball valve 35 and the retainer 38 is restricted. The relative displacement makes the center C of the ball valve 35 located on the axis A2 of the retainer 38 .

On the other hand, a circular recessed spring fitting portion 43 is formed at the bottom of the valve hole 34 . The spring fitting portion 43 is formed so that its axis coincides with the axis A1 of the valve hole 34, and the first end ring portion 37a of the safety valve spring 37 opposite to the valve seat member 36 is fitted into the spring fitting portion 43. close together so that the axis of the first end ring portion 37a coincides with the axis A1 of the valve hole 34 .

The valve seat member 36 has: a through hole 44 formed along the axis A1 of the valve hole 34 and communicating with the discharge passage 19b through the intermediate pressure chamber 28b; and an annular valve seat surface 45 formed in the through hole 44 The safety valve 33 is closed by fitting the ball valve 35 to the valve seat surface 45 in the opening formed on the side of the ball valve 35 .

The valve seat surface 45 is formed so that the center C of the ball valve 35 faces the common valve hole 34 of the first end ring portion 37a and the through hole 44 when the safety valve 33 is closed, that is, when the ball valve 35 is engaged with the valve seat surface 45 . The shaft center A1 is offset radially by a predetermined offset amount G3 (refer to FIG. 5 ). As a result, the ball valve holding portion 40 of the retainer 38 is offset in the radial direction with respect to the axis A1 of the valve hole 34 , and the axis A2 of the retainer 38 is inclined at an angle θ1 with respect to the axis A1 of the valve hole 34 .

4 and 5 are enlarged views showing the details of the valve seat surface 45, wherein FIG. 4 is an enlarged cross-sectional view showing the main part of the valve seat member 36 alone, and FIG. 5 shows the closed state of the ball valve 35 and the valve seat surface 45 enlarged sectional view of the .

As shown in Figure 4 and Figure 5 in detail, the valve seat surface 45 is formed by a part of the spherical surface with the same diameter as the ball valve 35 and whose center is offset by an offset amount G3 relative to the axis A1 of the valve hole 34, presenting a shape similar to that of the ball valve. The surface of valve seat surface 45 has a curved cross-sectional arc shape with the same curvature, and the width dimension gradually changes in the circumferential direction of valve seat surface 45 .

Specifically, the radially opposite positions in the valve seat surface 45 are respectively formed with a narrow portion 45a with the smallest width dimension of the valve seat surface 45 and a wide width portion 45b with the largest width dimension of the valve seat surface 45. The surface 45 is inclined toward the inner side of the through hole 44 (direction away from the first end ring portion 37a) toward the wide portion 45b side in the radial direction of the valve seat surface 45, and extends from the wide portion 45b to the narrow portion in the circumferential direction. The width dimension of the portion 45a is gradually narrowed. In other words, the valve seat surface 45 is formed such that the relative distance from the first end ring portion 37 a in the axial direction of the valve hole 34 varies in the circumferential direction of the valve seat surface 45 .

More specifically, the opening side edge portion 45c of the valve seat surface 45 is inclined toward the first end ring portion 37a in the axial direction of the valve hole 34 from the wide portion 45b toward the narrow portion 45a side, and the valve seat surface The inner side edge portion 45d of 45 is inclined toward the first end ring portion 37a in the axial direction of the valve hole 34 from the wide portion 45b toward the narrow portion 45a side than the opening side edge portion 45c. In other words, the inner edge portion 45d of the wide portion 45b is offset by a predetermined offset amount G1 to the side opposite to the first end ring portion 37a than the inner edge portion 45d of the narrow portion 45a, and the opening side edge of the wide portion 45b The opening side edge portion 45c of the narrow width portion 45a is offset by a predetermined offset amount G2 to the side opposite to the first end ring portion 37a, and the offset amount G1 of the inner side edge portion 45d is greater than that of the opening side edge portion 45c. The amount G2 is large. The wide portion side opening angle θ2 formed by the imaginary line connecting the both edge portions 45c, 45d of the wide portion 45b and the axis A1 of the valve hole 34 is larger than the imaginary line connecting the both edge portions 45c, 45d of the narrow portion 45a and The narrow portion side opening angle θ3 formed by the axis A1 of the valve hole 34 is large.

The seat surface 45 is formed by pressing a punch of a predetermined shape to the opening edge portion of the through hole 44 of the seat member 36 on the side of the ball valve 35 . Specifically, among the above-mentioned punches, at least the forming surface that realizes the forming of the valve seat surface 45 is formed as a part of a spherical surface having the same diameter as the ball valve 35, and the valve seat surface 45 is formed by using the punch, thereby, the safety valve 33 When the valve is closed, the ball valve 35 and the valve seat surface 45 are fitted together as a liquid-tight surface.

In the variable displacement vane pump 1 having the above configuration, when the safety valve 33 shown in FIG. 3 is closed, the center C of the ball valve 35 is offset toward the wide portion 45b side with respect to the axis A1 of the valve hole 34, as described above. The axis A2 of the retainer 38 is inclined toward the wide portion 45b side with respect to the axis A1 of the valve hole 34 . As a result, the pressing force F of the safety valve spring 37 acts in the direction of the axis A2 of the retainer 38 , and the ball valve 35 is forcibly pressed against the wide portion 45 b side of the valve seat surface 45 . In other words, the retainer 38 not only uses the axial component F1 of the pressure F to resist the hydraulic pressure in the through hole 44, but also uses the radial component F2 of the pressure F to press the ball valve 35 against the wide portion 45b of the valve seat surface 45. side part.

When the pressure in the intermediate pressure chamber 28b rises and exceeds the predetermined release pressure, as shown in FIG. The part on the side of the narrow width part 45a separates, and hydraulic fluid flows as shown by the arrow in FIG. 6 . That is, when the safety valve 33 is opened, the ball valve 35 is stably supported while being supported by the retainer 38 in contact with the wide portion 45 b side of the valve seat surface 45 , and the vibration of the ball valve 35 is suppressed. As shown in FIG. 3 , a sufficient gap is provided between the outer peripheral surface of the ball valve holding portion 40 of the retainer 38 and the outer peripheral surface of the valve hole 34 to prevent interference between the two when the safety valve 33 is opened.

Therefore, according to this embodiment, the release pressure of the safety valve 33 will not be unstable, and the vibration of the ball valve 35 when the safety valve 33 is opened can be suppressed to prevent noise when the safety valve 33 is opened.

In this embodiment, the seat surface 45 of the seat member 36 is formed as part of a spherical surface having the same diameter as the ball valve 35, but the spherical surface constituting the valve seat surface 45 does not necessarily have to have the same diameter as the ball valve.

7 is a view showing a state where a ball valve having a diameter different from that of the spherical surface constituting the valve seat surface 45 is fitted to the valve seat surface 45 as a modified example of the present embodiment. The ball valve having a larger diameter than the spherical surface constituting the valve seat surface 45 46 is indicated by a solid line, and on the other hand, a ball valve 47 having a smaller diameter than the spherical surface constituting the valve seat surface 45 is indicated by a dotted line.

Specifically, as in the modified example shown in FIG. 7, in the case of using ball valves 46, 47 having different diameters from the spherical surface constituting the valve seat surface 45, when the safety valve is closed, the centers of the ball valves 46, 47 are also opposite to the valve hole. The axial center A1 of 34 is offset toward the side of the wide portion 45b, so that substantially the same effect as that of the above-mentioned first embodiment can be obtained.

In the above-mentioned first embodiment, on the one hand, the through hole 44 of the valve seat member 36 is formed along the axis A1 of the valve hole 34; The common axis A1 of the through holes 44 is offset, but the axis of the through holes 44 and the center of the spherical surface constituting the valve seat surface 45 do not necessarily have to be offset. For example, even if both the coaxially formed through hole and the valve seat surface are offset in the radial direction with respect to the axis A1 of the valve hole 34, substantially the same effect as that of the above-mentioned first embodiment can be obtained.

8 to 10 are diagrams showing the second embodiment of the present invention. FIG. 8 is a cross-sectional view showing the safety valve in the closed state along the axial direction. FIG. 9 is an enlarged view of the main part of FIG. Diagram of the open state of the safety valve. 8 to 10 use the same reference numerals as those in FIGS. 1 to 7 for parts that are the same as or equivalent to those of the first embodiment shown in FIGS. 1 to 7 .

In the second embodiment shown in FIGS. 8 to 10 , when the valve seat surface 65 of the valve seat member 64 of the safety valve 63 is closed as shown in FIGS. 8 and 9 , the center C of the ball valve 35 is formed to be located in the valve hole. On the axis A1 of 34, on the other hand, as the end portion of the through hole 66 of the valve seat member 64 facing the valve body side, the axis A6 of the large-diameter portion 66a whose cross section opens to the ball valve 35 side is substantially circular. It is offset relative to the axis A1 of the valve hole 34 , and other parts are the same as the above-mentioned first embodiment.

Specifically, as shown in FIG. 9 , the valve seat surface 65 of the second embodiment is formed in an annular shape with a part of a spherical surface having the same diameter as the ball valve 35 . The center C is offset from the axis A6 of the large-diameter portion 66a, and the width dimension is gradually changed in the circumferential direction as in the first embodiment described above. That is, the valve seat surface 65 is formed as a part of a spherical surface whose center is offset with respect to the axis A6 of the large-diameter portion 66a. The symbol 65a in FIGS. 8 to 10 indicates the widest portion of the valve seat surface 65 having the largest width, and the symbol 65b in FIGS. 8 to 10 indicates the narrowest portion of the valve seat surface 65 .

Therefore, in the second embodiment, in the closed state shown in FIG. 9, although the pressure F3 of the safety valve spring 37 acts in the direction along the axis A1 of the valve hole 34, since the center C of the ball valve 35 is relatively Since the axis A6 of the large-diameter portion 66a that part of the outer surface of the ball valve 35 faces is offset, the pressing force F4 that presses the ball valve 35 in the valve-opening direction is inclined toward the wide-width portion 65a by the hydraulic pressure p in the large-diameter portion 66a. . That is, the ball valve 35 is decomposed by the pressing force F4 while the radial component F5 in the direction perpendicular to the axis A6 of the large-diameter portion 66a, which is decomposed by the pressing force F4, is pressed against the wide portion 65a side of the valve seat surface 65. The axial component F6 along the axial center A6 direction of the large-diameter portion 66a is pressed in the valve opening direction.

As shown in FIG. 10, when the pressure in the large-diameter portion 66a, that is, the pressure in the medium-pressure chamber 28b exceeds the specified release pressure, the radial component F5 of the pressing force F4 of the ball valve 35 will move toward the wide portion 65a of the seat surface 65. The side part is pressed, so while keeping in contact with the part of the valve seat surface 65 on the side of the wide part 65a, it moves away from the part of the valve seat surface 65 on the side of the narrow part 65b. flow. Therefore, in this second embodiment, as in the first embodiment described above, the vibration of the ball valve 35 can be suppressed when the safety valve 63 is opened, and substantially the same effects as in the first embodiment described above can be obtained.

FIG. 11 is a cross-sectional view showing a safety valve 48 of a variable displacement vane pump as a third embodiment of the present invention. FIG. 12 is a sectional view showing the retainer 51 of the safety valve 48 alone.

In the third embodiment shown in FIG. 11, the valve seat surface 50 of the valve seat member 49 is formed such that the center of the spherical surface constituting the valve seat surface 50 is located on the axis A1 of the valve hole 34, and the retainer 51 is formed as a ball valve. The ball valve holding recess 53 of the valve body holding recess of the holding portion 52 is formed such that the center C of the ball valve 35 is offset in the radial direction with respect to the axis A3 of the retainer 51 . The retainer 51 is also the same as the above-mentioned first embodiment except that it has the shaft portion 54 similarly to the above-mentioned first embodiment.

Specifically, as shown in FIG. 12 , the ball valve holding concave portion 53 has a cross-sectional shape that gradually expands from the deepest portion 55 on the axial center A3 of the retainer 51 toward the opening side, and roughly deforms in a mortar shape. The radius from the center A3 to the opening edge portion 56 of the ball valve holding recess 53 gradually changes in the circumferential direction of the opening edge portion 56 . Specifically, the smallest radius portion 57 having the smallest radius R1 in the opening edge portion 56 and the largest radius portion 58 having the largest radius R2 in the opening edge portion 56 are respectively formed at opposite positions in the radial direction, from the smallest radius portion 57 toward the largest radius portion. The radius of the opening edge portion 56 of the radius portion 58 gradually increases in the circumferential direction. In other words, the angle formed by the ball valve retaining recess 53 relative to the axis A3 of the retainer 51 is the minimum angle θ4 at the circumferential position corresponding to the minimum radius portion 57 on the one hand, and the minimum angle θ4 at the circumferential position corresponding to the maximum radius portion 58 on the other hand. The position gradually changes in the circumferential direction at a maximum angle θ5. Thereby, as shown in FIG. 11 , the center C of the ball valve 35 is offset toward the maximum radius portion 58 with respect to the axis A2 of the retainer 51 .

Therefore, in this third embodiment, the ball valve holding portion 52 of the retainer 51 is radially biased with respect to the first end ring portion 37a of the safety valve spring 37 similarly to the above-mentioned first embodiment, so that the retainer 51 Since the axis A3 is inclined by the angle θ6 with respect to the axis A1 of the valve hole 34, substantially the same effect as that of the above-mentioned first embodiment can be obtained.

FIG. 13 is a sectional view showing the retainer 59 alone as a modified example of the third embodiment described above.

In the modified example shown in FIG. 13 , the ball valve holding recess 61 formed in the ball valve holding portion 60 of the retainer 59 is formed in a substantially mortar shape that is rotationally symmetrical about the axis A4 of the ball valve holding recess 61 , and the ball valve The axis A4 of the holding recess 61 is radially offset from the axis A5 of the holder 59 . The retainer 59 is also the same as the third embodiment described above except that it has the shaft portion 62 similarly to the third embodiment described above.

Therefore, in this modified example, the center C of the ball valve 35 is offset in the radial direction with respect to the axis A5 of the retainer 59 similarly to the above-mentioned third embodiment, so there is an advantage that the same effect as that of the above-mentioned third embodiment can be obtained. .

As a fourth embodiment of the present invention, as shown in FIGS. 14 to 16, instead of the structure using the retainer 51 in the above-mentioned third embodiment, the retainer 38 can also be used as the coil spring of the present invention, that is, the safety valve spring 68. The axis A2 of the valve hole 34 is inclined relative to the axis A1 of the shape. In Figs. 14 to 16, the same symbols as those in Figs. 11 and 12 are used for parts that are the same as or equivalent to those of the third embodiment shown in Figs. 11 and 12 .

Specifically, in the safety valve 67 of the fourth embodiment, the retainer 38 holds the ball valve 35 on the axis A2 of the retainer 38 similarly to the above-mentioned first embodiment, and connects the safety valve spring 68 to the valve hole 34. The fitting surface 68a that fits the inner bottom surface 34a of the safety valve spring 68 is formed to be inclined with respect to a virtual plane P perpendicular to the axis A7 of the safety valve spring 68 when the safety valve spring 68 shown in FIG. 15 is in a free state. Symbol θ7 shown in FIG. 15 represents an inclination angle of the fitting surface 68 a with respect to the virtual plane P. As shown in FIG. In the safety valve spring 68 , a fitted surface 68 b to be fitted with the stepped portion 42 of the retainer 38 is formed parallel to the virtual plane P in the free state of the safety valve spring 68 . Other parts are the same as the above-mentioned third embodiment.

As shown in FIG. 14, when the safety valve spring 68 formed in this way is interposed between the inner bottom surface 34a of the valve hole 34 and the stepped portion 42 of the retainer 38, the safety valve spring 68 is compressed while bending its axis. While being deformed, the retainer 39 is pressed against the valve seat member 49 side by the restoring force of the compression deformation. That is, the safety valve spring 68 makes the axis A2 of the retainer 39 inclined at an angle θ1 relative to the axis A1 of the valve hole 34, and utilizes the pressing force F along the axis A2 of the retainer 39 to push the retainer 39 toward the valve seat. Part 49 presses sideways.

Therefore, when the pressure in the through hole 44 of the valve seat member 49, that is, the pressure in the intermediate pressure chamber 28b exceeds the predetermined release pressure, as shown in FIG. Partial abutment moves away from the valve seat surface 50 on the other side in the radial direction, and the safety valve opens. Accordingly, in this fourth embodiment, the vibration of the ball valve 35 can be suppressed even when the safety valve 37 is opened, and substantially the same effect as that of the third embodiment described above can be obtained.

Here, the technical idea grasped from each of the above-described embodiments, and the contents not described in the claims are described below together with their effects.

(1) The variable displacement vane pump described in the second aspect of the present invention is characterized in that the relative distance of the valve seat surface from the first end ring portion in the axial direction of the valve hole is formed such that Circumferential changes of the surface.

In the technical idea described in (1), the valve body deeply enters the valve seat member at a portion away from the first end ring portion of the coil spring of the valve seat surface, so the valve body The center of the valve hole is radially offset relative to the axis of the valve hole.

(2) The variable capacity vane pump as described in (1), wherein the valve seat surface faces the radial side of the valve seat surface in the axial direction of the valve hole and is in the axial direction of the valve hole inclined in a direction away from the first end ring portion.

In the technical idea described in (2), since the portion of the valve seat surface on one side in the radial direction is separated from the first end ring portion than the portion on the other side in the radial direction of the valve seat surface, in this A part of the valve body penetrates deeply into the valve seat member, and the center of the valve body is offset to one side in the radial direction relative to the axis of the valve hole.

(3) The variable capacity vane pump as described in (2), wherein the valve seat surface is formed by pressing a punch to the valve seat member, and at least The forming surface of the valve seat surface is formed as a part of a spherical surface having the same diameter as the valve body.

In the technical idea described in (3), since the valve body is in surface contact with the valve seat surface, the liquid tightness when the safety valve is closed can be improved.

(4) The variable displacement vane pump according to the content (3) of the present invention is characterized in that the valve body holding part has a valve body holding concave part for holding the valve body, and the valve body holding concave part faces from the deepest part to The opening side presents a mortar shape whose diameter gradually expands, and the deepest part of the valve body holding recess is offset in the radial direction with respect to the axis of the valve body holding member.

In the technical idea described in (4), by offsetting the deepest part of the valve body holding recess in the radial direction with respect to the axis center of the valve body holding member, it is possible to make the center of the valve body relative to the valve body. The body keeps the axis of the member radially offset.

Claims (1)

1. A variable capacity vane pump with: a rotor, which is arranged in the accommodation space in the pump main body, and has a plurality of blades arranged freely in the radial direction, and the rotor is driven to rotate by the drive shaft; a cam ring disposed on the outer peripheral side of the rotor so as to be movable in a direction in which an eccentricity of the rotor varies, and forms a plurality of pump chambers together with each of the vanes and the rotor; a suction passage communicating with a suction area in the housing space where the volume of each of the pump chambers increases as the rotor rotates; a discharge passage communicating with a discharge area in the storage space where the volume of each of the pump chambers decreases as the rotor rotates; a pressure control mechanism, which controls the pressure of at least one of a pair of fluid pressure chambers formed on both radial sides of the cam ring, so as to control the eccentricity of the cam ring relative to the rotor; a safety valve provided in the pump main body to open and close an oil passage between the discharge passage and the suction passage; This variable capacity vane pump is characterized in that The safety valve has: a valve hole disposed within the pump body; a valve body in the shape of a ball valve, which is arranged in the valve hole; The valve seat member is fixed on one side of the valve hole in the axial direction with the valve body interposed therebetween, and is formed with a through hole communicating with the discharge passage, and a ring fitted with the valve body when the valve is closed. A valve seat surface is formed on the valve body side opening of the through hole; a coil spring disposed on the other side across the valve body in the valve hole; A valve body holding member, which is provided between the valve body and the coil spring, is formed on the side of the valve body to limit the relative displacement in the radial direction with respect to the valve body and to hold the valve body. part, and a spring engaging part is formed on the side of the coil spring to limit its relative displacement relative to the coil spring in the radial direction, and the valve body is pushed toward the valve body by the restoring force generated by the compression deformation of the coil spring. Side pressure of the valve seat part; The valve seat surface is formed such that when the valve body is fitted to the valve seat surface to close the valve, the center of the valve body faces the valve body facing the valve body in the through hole of the valve seat member. The axis of the side end is offset.