JP3532954B2 - Control valve for hydraulic power steering system - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary type hydraulic control valve for controlling a hydraulic pressure acting on a hydraulic actuator for generating a steering assist force of a hydraulic power steering apparatus. 2. Description of the Related Art A conventional control valve for a hydraulic power steering apparatus shown in FIG. 5 has a cylindrical first valve member 101 and a second valve inserted into the first valve member 101 so as to be relatively rotatable. And a member 102. The first valve member 1
A plurality of recesses 101d and 102a along the axial direction are formed at equal intervals in the circumferential direction on the inner circumference of the first valve member 01 and the outer circumference of the second valve member 102. A part of the second valve member side concave portion 102a is a plurality of pressure oil supplying concave portions 102a 'which are located at equal intervals in the circumferential direction and communicate with the pump. Between the first valve member-side concave portion 101d and the second valve member-side concave portion 102a is a throttle portion whose opening degree changes due to the relative rotation of the two valve members 101, 102. The hydraulic pressure acting on the generating hydraulic actuator is controlled (see Japanese Utility Model Publication No. 1-4977). In this control valve, in order to prevent relative vibration of the first valve member 101 and the second valve member 102 due to pulsation of pressure oil discharged from the pump, one axial end of each of the recesses 101d and 102a. A first peripheral groove 102b is formed on the outer periphery of the second valve member on the outer side in the axial direction. An annular elastic member 103 is inserted into the first peripheral groove 102b, and the first peripheral groove 102b and the pressure oil supply recess are formed. 10
Single first slit 102c communicating with one of the second slits 2a '
Are formed on the second valve member 102. The circumferential dimension of the first slit 102c is the pressure oil supply recess 102.
a 'is smaller than the circumferential dimension of a'. As a result, the first slit 1
02c is supplied to the first peripheral groove 102b through the second peripheral groove 102c, and the supplied pressure oil stretches the annular elastic member 103 radially outward and presses the annular elastic member 103 against the inner peripheral surface of the first valve member 101.
The relative vibration between the valve member 101 and the second valve member 102 is prevented. In order to equalize the gap between the two valve members 101 and 102 in the axial direction when high-pressure oil acts, a second valve is provided at the other axial end of each of the recesses 101d and 102a. The second peripheral groove 102d is formed on the outer periphery of the member.
Are formed, and the second peripheral groove 102d and the first peripheral groove 10d are formed.
A single second slit 102e is formed in the second valve member 102 to communicate with one pressure oil supply recess 102a 'communicated with 2b. The circumferential dimension of the second slit 102e is smaller than the circumferential dimension of the pressure oil supply recess 102a '. Thereby, the pressure oil is supplied from the pressure oil supply concave portion 102a 'to the second circumferential groove 102d through the second slit 102e. That is, since the pressure oil is supplied to both the circumferential grooves 102b and 102d formed at intervals in the axial direction, the load that reduces the first valve member 101 in the radial direction from the outer peripheral surface of the first valve member 101 is provided. And the load for expanding the first valve member 101 in the radial direction is substantially balanced by the pressure oil supplied to the circumferential grooves 102b and 102d of the second valve member 102, so that the inner circumference of the first valve member 101 and the second The gap with the outer periphery of the valve member 102 is made uniform in the axial direction. Thereby, the relative rotation of the two valve members 101 and 102 is smoothed, and the gap between the inner and outer circumferences of the two valve members 101 and 102 is set to a minimum to prevent oil leakage. [0005] The first valve member 101 comprises a cylindrical main body 101a, and annular portions 101b and 101c which are press-fitted at both inner peripheral ends of the main body 101a. The concave portion 10 on the inner periphery of the first valve member 101
1d is a bottom surface 1 of the groove along the axial direction of the main body 101a.
01a 'and end faces 101 of the annular portions 101b and 101c
b 'and 101c'. This allows
Processing of the main body 101a is facilitated. [0006] In the above-mentioned conventional hydraulic control valve, the vibration cannot be sufficiently prevented in spite of the provision of the vibration damping means, and unpleasant vibration noise is generated. And the vibrations are transmitted to the steering wheel to cause discomfort to the driver. An object of the present invention is to provide a control valve for a hydraulic power steering device which can solve the above problems. A control valve for a hydraulic power steering apparatus according to the present invention comprises a first cylindrical valve member and a second valve member rotatably inserted into the first valve member. A plurality of recesses along the axial direction are formed on the inner periphery of the first valve member and the outer periphery of the second valve member at intervals in the circumferential direction, and a part of the second valve member-side recesses is mutually formed. A plurality of pressure oil supply recesses are provided at intervals in the circumferential direction and communicate with the pressure oil supply means, and a space between the first valve member side recess and the second valve member side recess is formed by relative rotation of the two valve members. The opening degree is changed to a throttle portion, and the hydraulic pressure acting on the steering assist force generating hydraulic actuator is controlled by the change in the opening degree of the throttle portion. A circumferential groove is formed on the outside An annular elastic member is inserted into at least one of the two circumferential grooves, and a communication recess extending axially outward from both axial ends of each of the pressure oil supply recesses is formed. The oil supply recess is communicated with both circumferential grooves, and each pressure oil supply recess and each communication recess have the same circumferential dimension. The pressure oil supply recesses are preferably arranged at equal intervals in the circumferential direction. The present inventor has found that despite the fact that a conventional control valve for a hydraulic power steering system has a vibration damping means for the first valve member 101, it is impossible to obtain a sufficient vibration damping effect. Found that there was a response delay in the damping action. That is, in the conventional structure, the pressure oil supply concave portion 102a '
Therefore, the supply speed of the pressure oil to each of the circumferential grooves 102b and 102d is low, and the hydraulic pressure cannot be applied to the annular elastic member 103 quickly, so that the vibration damping effect cannot be achieved. In order to speed up the supply of the pressure oil from the pressure oil supply recess 102a 'to each of the peripheral grooves 102b and 102d, the depth of each of the slits 102c and 102e may be increased to increase the flow path area. Conceivable. However, each slit 102c, 102e is usually
Since the slits 102c and 102e are formed too deep by cutting the outer circumference of the valve member 102, the milling cutters cut off the wall surfaces on the axially outward sides of the circumferential grooves 102b and 102d, and leak pressure oil. There is a risk. On the other hand, according to the structure of the present invention, the pressure oil is supplied from the plurality of pressure oil supply recesses to the respective circumferential grooves through the plurality of communication recesses. Since the circumferential dimension is equal to that of the passage recess, hydraulic pressure acts on the annular elastic member 103 from the single pressure oil supply recess 102a 'through the single slit 102c as in the conventional case, and the slit 102c Can be made to act on the annular elastic member more quickly than in the case where the circumferential dimension of is smaller than the circumferential dimension of the pressure oil supply recess 102a '. Thereby, the vibration damping effect of the first valve member can be reliably achieved. In addition, since the pressure oil can be quickly supplied to both the circumferential grooves formed at intervals in the axial direction, the hydraulic pressure does not act unevenly on the first valve member in the axial direction. The gap between the valve member and the second valve member can be made uniform in the axial direction. This makes it possible to smooth the relative rotation of the two valve members and to prevent oil leakage. Further, when the pressure oil is supplied to each of the circumferential grooves from the single pressure oil supply recess as in the related art, at the beginning of the supply of the pressure oil, the hydraulic pressure acts on the annular elastic member in the circumferential direction so that the first pressure oil is supplied. The gap between the valve member and the second valve member may be uneven in the circumferential direction. On the other hand, by arranging a plurality of pressure oil supply recesses communicating with each circumferential groove at equal intervals in the circumferential direction, the gap between the first valve member and the second valve member is made uniform in the circumferential direction. You. This makes it possible to smooth the relative rotation of the two valve members and to prevent oil leakage. By making the circumferential size of each pressure oil supply recess and each communication recess equal, the pressure oil supply recess and the communication recess can be machined by a single tool such as a milling cutter. , And the processing cost can be reduced. Embodiments of the present invention will be described below with reference to the drawings. A rack and pinion type hydraulic power steering device 1 shown in FIG. 1 has an input shaft 2 connected to a steering handle (not shown), and a torsion bar 3 connected to the input shaft 2.
And an output shaft 4 which is connected to the output shaft 4. The torsion bar 3 is connected to the input shaft 2 via a pin 5 and
It is connected to the output shaft 4 via a serration 6. A pinion 7 is formed on the output shaft 4, and a rack 8 that meshes with the pinion 7 is connected to steering wheels (not shown). The input shaft 2 is supported by a valve housing 10 a via a bearing 9, and is supported by the output shaft 4 via a bearing 11. The output shaft 4 is the bearing 1
It is supported by the rack housing 10b via 2 and 13. As a result, the rotation of the input shaft 2 due to the steering is transmitted to the pinion 7 via the torsion bar 3, and the rack 8 moves in the vehicle width direction, and the wheels are steered by the movement of the rack 8. Note that oil seals 14, 15 are provided between the input / output shafts 2, 4 and the valve housing 10a. A support yoke 16 for supporting the rack 8 is provided.
The support yoke 16 is pressed against the rack 8 by the elastic force of a spring 17. A hydraulic cylinder 18 is provided as a hydraulic actuator for applying a steering assist force. The hydraulic cylinder 18 includes a cylinder tube 19 constituted by a rack housing 10b, and a piston 20 formed integrally with the rack 8, and a pair of oil chambers 21 and 22 partitioned by the piston 20 are formed. Each oil chamber 2
A rotary hydraulic control valve 23 is connected to 1 and 22. The control valve 23 includes a cylindrical first valve member 24 and a second valve member 25 inserted into the first valve member 24 so as to be relatively rotatable. The first valve member 24 includes a cylindrical main body 24a and a main body 2a.
It has annular portions 24b and 24c which are press-fitted to both inner peripheral ends of the inner shaft 4a, and is rotatably attached to the output shaft 4 via pins 26. The second valve member 25 is formed integrally on the outer periphery of the input shaft 2. As shown in FIG. 2, both annular portions 24b, 24
A plurality of concave portions along the axial direction are formed at equal intervals in the circumferential direction on the inner periphery of the first valve member 24 and the outer periphery of the second valve member 25 between c. The first valve member-side recesses are provided with four right steering recesses 27 located at equal intervals in the circumferential direction.
And four left steering recesses 28 located at equal intervals in the circumferential direction. The second valve member-side recess has four pressure oil supply recesses 29 located at equal intervals in the circumferential direction.
And four pressure oil discharge recesses 30 located at equal intervals in the circumferential direction. The right steering recesses 27 and the left steering recesses 28 are alternately arranged in the circumferential direction, and the pressure oil supply recesses 29 and the pressure oil discharge recesses 30 are alternately arranged in the circumferential direction. Each right steering recess 27 is provided with a first passage 31 formed in the first valve member 24 and the valve housing 10a.
Through the first port 32 formed to the oil chamber 21 of the hydraulic cylinder 18. Each left steering recess 28 communicates with the other oil chamber 22 of the hydraulic cylinder 18 via a second flow path 33 formed in the first valve member 24 and a second port 34 formed in the valve housing 10a. Each pressure oil supply recess 29 is provided in the third flow path 3 formed in the first valve member 24.
5 and a pump 37 through an inlet port 36 formed in the valve housing 10a. Each pressure oil discharge recess 3
0 is a first discharge path 38 formed in the second valve member 25,
The tank 4 passes through a passage 47 between the input shaft 2 and the inner and outer circumferences of the torsion bar 3, a second discharge passage 39 formed in the input shaft 2, and a discharge port 40 formed in the valve housing 10a.
Lead to 1. Thereby, the pump 37 and the tank 4
The first and second oil chambers 21 and 22 of the hydraulic cylinder 18 communicate with each other through an inter-valve flow path 42 between the inner and outer circumferences of the first valve member 24 and the second valve member 25. Also, in the inter-valve flow path 42, between the first valve member-side concave portion and the second valve member-side concave portion, there are throttle portions A, B, C, and D whose opening degree changes due to relative rotation of the two valve members 24 and 25. And the apertures A, B,
The hydraulic pressure acting on the hydraulic cylinder 18 is controlled by the change in the opening degree of C and D. That is, FIG. 2 shows the relative positions of the two valve members 24 and 25 in a non-steering state. In this state, each pressure oil supply recess 29 and each pressure oil discharge recess 30 are connected. Since all the throttle portions A, B, C, and D communicate with each other, the pressure oil supplied from the pump 37 is directly returned to the tank 41 and no steering assist force is generated. When the steering wheel is steered to the right from the state where no steering assist force is generated, the torsion bar 3 is twisted in accordance with the steering resistance applied to the wheels from the road surface, and the two valve members 24 and 25 rotate relatively. As a result, the opening degree of the throttle portion A between each right steering recess 27 and each pressure oil supply recess 29 and the throttle portion B between each left steering recess 28 and each pressure oil discharge recess 30 are determined. The degree of opening increases, and the degree of opening of the throttle portion C between each left steering recess 28 and each pressure oil supply recess 29 and each right steering recess 2 is increased.
The degree of opening of the throttle portion D between the nozzle 7 and each of the pressure oil discharge recesses 30 is reduced. As a result, the hydraulic cylinder 1
8 is supplied with pressure oil to one oil chamber 21 of the hydraulic cylinder 1.
8, the pressure oil is recirculated from the other oil chamber 22 to the tank 41,
The steering assist force to the right of the vehicle acts on the rack 8 according to the steering resistance. When the steering wheel is steered to the left, each of the apertures A,
Since the opening degrees of B, C, and D change in reverse to the case of steering to the right, the steering assisting force to the left of the vehicle acts on the rack 8 according to the steering resistance. As shown in FIG. 3, circumferential grooves 43 and 44 are formed on the outer periphery of the second valve member 25 at the axial ends of the recesses 29 and 30 at the axial ends.
An annular elastic member 45 is inserted into the second member. One of the peripheral grooves 43 is communicated with each pressure oil supply recess 29 via four communication recesses 46 a extending from one axial end of each pressure oil supply recess 29. The other circumferential groove 44 has four communicating recesses 46 extending from the other axial end of each pressure oil supply recess 29.
Each of the pressure oil supply recesses 29 communicates with the corresponding one of the pressure oil supply recesses 29 through the corresponding b. Each of the pressure oil supply recesses 29 and each of the communication recesses 46a and 46b have the same circumferential dimension. In addition, each communication recess 4
6a, 46b and the respective circumferential grooves 43, 44 are connected to the first valve member 24.
Are disposed radially inward of the annular portions 24b and 24c. According to the above configuration, each pressure oil supply recess 29 is provided.
Through the respective communication recesses 46a, 46b from the respective circumferential grooves 43, 4
4 is supplied with pressure oil, and the supplied pressure oil causes the annular elastic member 45 to be stretched radially outward so that the first valve member 24
And the first valve member 24 is damped. At this time, the pressurized oil is supplied from the plurality of pressurized oil supply recesses 29 to the respective circumferential grooves 43 and 44 through the plurality of communication recesses 46a and 46b, and furthermore, the respective pressurized oil supply recesses 29 and the respective communication recesses 46a , 46b have the same circumferential dimension, so that the hydraulic pressure can be quickly applied to the annular elastic member 45. Thereby, relative vibration between the first valve member 24 and the second valve member 25 can be reliably suppressed. In addition, since the pressure oil can be quickly supplied to both the circumferential grooves 43 and 44 formed at intervals in the axial direction,
The hydraulic pressure does not act unevenly on the first valve member 24 in the axial direction, and the gap between the two valve members 24 and 25 can be made uniform in the axial direction. Further, since the plurality of recesses 29 for supplying pressure oil which are communicated with the respective circumferential grooves 43 and 44 are arranged at equal intervals in the circumferential direction, the hydraulic pressure does not act on the annular elastic member 45 in the circumferential direction. The gap between the first valve member 24 and the second valve member 25 is made uniform in the circumferential direction. As a result, the relative rotation between the two valve members 24 and 25 can be smoothed and oil leakage can be prevented. Also, by making the circumferential dimension of each pressure oil supply recess 29 and each communication recess 46a, 46b equal,
The pressure oil supply recess 29 and the communication recesses 46a and 46b are formed by a single milling cutter M as shown by a two-dot chain line in FIG.
And processing cost can be reduced. The present invention is not limited to the above embodiment. For example, in the above embodiment, the present invention was applied to a rack and pinion hydraulic power steering apparatus.
It can also be applied to a ball screw type hydraulic power steering device. In addition, the number of pressure oil supply recesses is not particularly limited as long as it is plural. Further, the annular elastic member may be inserted into both the circumferential grooves. According to the control valve of the present invention, the vibration damping effect of the valve member is reliably achieved, the relative rotation of the two valve members is smoothed, oil leakage is prevented, and the processing cost can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a hydraulic power steering apparatus according to an embodiment of the present invention. FIG. 2 is a transverse sectional view of a control valve of the present invention. FIG. FIG. 4 is a cross-sectional view of a main part of a control valve according to an embodiment of the present invention. FIG. 5 is an explanatory view of a configuration of a conventional control valve. 24c Annular portion 25 Second valve member 29 Pressure oil supply concave portions 43, 44 Peripheral groove 45 Annular elastic members 46a, 46b Communication concave portions A, B, C, D Throttle portion

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B62D 5/00-5/30

Claims (1)

(57) Claims 1. A first valve member having a cylindrical shape, and a second valve member inserted into the first valve member so as to be rotatable relative to the first valve member. A plurality of recesses along the axial direction are formed in the circumference and the outer circumference of the second valve member at intervals in the circumferential direction. A plurality of pressure oil supply recesses communicating with the pressure oil supply means, and a portion between the first valve member-side recess and the second valve member-side recess serving as a throttle portion whose opening degree changes due to relative rotation of the two valve members; The hydraulic pressure acting on the hydraulic actuator for generating steering assist force is controlled by the change in the opening degree of the throttle portion, and a circumferential groove is formed on the outer periphery of the second valve member at the axially outer ends of both axial ends of each of the concave portions. An annular elastic member is inserted into at least one of the circumferential grooves. A communication recess extending axially outward from each axial end of each of the pressure oil supply recesses is formed, and each of the pressure oil supply recesses is communicated with both circumferential grooves via each of the communication recesses. The recesses for communication and the recesses for communication have the same circumferential dimension , and the pressure
The oil supply recesses are arranged at equal intervals in the circumferential direction,
Control valve for a hydraulic power steering device in which a recess for communication and a recess for communication are machined by a single tool .