JPH11165648A - Hydraulic control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic control valve which can improve stability at the time of straight running of a vehicle without increasing the number of part items, manhour for assembling, manufacturing cost, and dimensions of the device when it is applied to a hydraulic power steering device. SOLUTION: A cylindrical valve member 31 fitted in a relatively rotatable manner on a housing and a first shaft 2 is connected in a jointly rotatable manner to a second shaft 2 which is connected to the first shaft 2 in a coaxially centered and elastically relatively rotatable manner through a torsion bar 6 so that displacement to one side in an axial direction may be regulated, and displacement to the other side in the axial direction may be permitted. A retaining ring 70 fitted at the outer periphery of the first shaft 2 is jointed to the valve member 31 and the first shaft 2 so as to be elastically deformed by the relative rotation against the first shaft 2 of the valve member 31 so as to regulate displacement to the other side in the axial direction of the valve member 31, thus it is possible to apply pre-load in such a direction as to regulate the relative rotation from a neutral position against the first shaft 2 of the valve member 31.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve for controlling a hydraulic pressure by changing an opening degree of a throttle portion by rotating a valve member.
It is suitable for controlling a hydraulic pressure acting on a hydraulic actuator for generating a steering assist force in a hydraulic power steering device.

[0002]

2. Description of the Related Art An output shaft is connected to an input shaft which is rotated by steering via a torsion bar so as to be relatively rotatable around a coaxial center, and a rack is meshed with a pinion formed on the output shaft. 2. Description of the Related Art Conventionally, a steering device that changes a steering angle by transmitting rotation of a vehicle to wheels via a torsion bar, an output shaft, a pinion, and a rack has been used. In such a steering device, a so-called rotary type hydraulic control valve is used to apply a steering assist force by a hydraulic actuator.

The hydraulic control valve has a cylindrical valve member which is fitted between the inner periphery of the housing and the outer periphery of the input shaft so as to be rotatable relative to the housing and the input shaft. In the oil passage between the input shaft and the valve member,
A throttle portion is formed so that the opening degree changes by the relative rotation of the input shaft and the valve member. The valve member is rotatably connected to the output shaft.

According to the hydraulic control valve, when the torsion bar is elastically twisted due to the steering resistance, the valve member rotates relative to the input shaft to change the opening degree of the throttle. The hydraulic pressure corresponding to the opening of the hydraulic actuator acts on the hydraulic actuator. Thereby, a steering assist force is applied according to the steering resistance.

When the application of the steering force is released, the valve member rotates relative to the input shaft due to the elastic force of the torsion bar, and can return to the neutral position with respect to the input shaft.

In the above hydraulic control valve, only the torsion bar gives resilience to hold the valve member 31 at the neutral position with respect to the input shaft. For this reason, there is a problem that the stability during straight running decreases.

Therefore, there has been proposed a hydraulic power steering apparatus in which a C-shaped spring separate from the torsion bar exerts an elastic force for returning the valve member to the neutral position with respect to the input shaft (Japanese Patent Laid-Open No. 2-133283). reference). The C-shaped spring applies a preload in a direction that restricts the relative rotation of the valve member from the neutral position with respect to the input shaft. Thus, even if the driver's steering force increases, high pressure oil is not supplied to the steering assist force generating hydraulic actuator until the preload is released, so that the stability during straight running can be improved. Also, at the time of stationary steering or low-speed steering, the pressure of the hydraulic oil applied to the hydraulic cylinder by releasing the preload is increased, and a sufficient steering assist force can be obtained.

[0008]

In the above-mentioned conventional hydraulic control valve, since a C-shaped spring needs to be newly provided, there is a problem that the number of parts, the number of assembling steps, and the manufacturing cost are increased. In addition, since the C-shaped spring is arranged between the valve member and the output shaft, there is a problem that the size of the device is increased in order to secure an arrangement space.

[0009] An object of the present invention is to provide a hydraulic control valve capable of solving the above problems.

[0010]

According to the present invention, there is provided a hydraulic control valve comprising:
A first shaft, a second shaft, a torsion bar for connecting the first shaft and the second shaft elastically and relatively rotatably about a coaxial center, and between an inner periphery of the housing and an outer periphery of the first shaft. , A cylindrical valve member fitted to the housing and the first shaft so as to be relatively rotatable. A throttle portion is formed in the oil passage between the first shaft and the valve member such that the opening degree changes by the relative rotation of the first shaft and the valve member. The valve member is rotatably connected to the second shaft such that displacement in one axial direction is restricted and displacement in the other axial direction is permitted. A retaining ring is fitted around the outer periphery of the first shaft so as to regulate the displacement of the valve member in the other axial direction. The valve ring and the first ring are elastically deformed by relative rotation of the valve member with respect to the first shaft.
Connected to the shaft. The retaining ring is characterized in that a preload can be applied in a direction that restricts relative rotation of the valve member from the neutral position with respect to the first shaft. According to the configuration of the present invention, the retaining ring that regulates the axial displacement of the valve member can apply a preload in the direction that regulates the relative rotation of the valve member from the neutral position with respect to the input shaft. This eliminates the need for a dedicated member for applying the preload, thereby preventing an increase in the number of parts, the number of assembly steps, and the manufacturing cost.

[0011] The retaining ring is preferably arranged in a space between an inner periphery of the housing and an outer periphery of the first shaft, which constitute a part of the pressure oil discharge passage. Thus, it is possible to prevent the apparatus from being enlarged in order to apply the preload.

It is preferable that the hydraulic pressure acting on the hydraulic actuator for generating the steering assist force of the hydraulic power steering device of the vehicle can be controlled by changing the opening degree of the throttle. As a result, even if the driver's steering force increases, high-pressure oil is not supplied to the hydraulic actuator for generating steering assist force until the preload applied by the retaining ring is released, so that the vehicle is stable when traveling straight. Performance can be improved. Further, at the time of stationary steering or low-speed steering, the pressure of the hydraulic oil applied to the hydraulic cylinder 20 by releasing the preload is increased, and a sufficient steering assist force can be obtained.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

A rack and pinion type hydraulic power steering device 1 for a vehicle shown in FIG. 1 includes a cylindrical input shaft (first shaft) 2 connected to a steering wheel H,
An output shaft 3 connected to the input shaft 2 via a torsion bar 6 so as to be elastically and relatively rotatable about the same axis.
And The torsion bar 6 is connected to the input shaft 2 via a pin 4 and connected to the output shaft 3 via a serration 5. The input shaft 2 is
Supported by a valve housing 7 via a bearing 8;
The output shaft 3 is supported via a bush 12. The output shaft 3 is supported on the rack housing 9 via bearings 10 and 11. A pinion 15 is formed on the output shaft 3.
Wheels (not shown) are connected to a rack 16 that meshes with. The rotation of the input shaft 2 due to steering is transmitted to the torsion bar 6, the output shaft 3, and the pinion 15, and the steering angle changes due to the axial movement of the rack 16 due to the rotation of the pinion 15. Note that the rack 16 is supported by a rack soldering 9 via a support yoke 40, and the support yoke 40 is
6, the support yoke 40 is displaced to absorb the bend of the rack 16 and the like.
And the rack 16 is smoothly engaged.

A hydraulic cylinder 20 is provided as a hydraulic actuator for generating a steering assist force. The hydraulic cylinder 20 includes a cylinder tube formed by the rack housing 9 and a piston 21 integrated with the rack 16.
It has. The oil chambers 22 and 23 partitioned by the piston 21 are provided with a rotary hydraulic control valve 30 that supplies pressure oil according to the magnitude and direction of steering resistance.

The hydraulic control valve 30 has a cylindrical shape fitted between the inner periphery of the valve housing 7 and the outer periphery of the input shaft 2 so as to be relatively rotatable with respect to the valve housing 7 and the input shaft 2. A valve member 31 is provided.

As shown in FIG. 2, the output shaft 3 restricts the displacement of the valve member 31 in one axial direction (downward in the figure) and allows the displacement in the other axial direction (upward in the figure). So as to be rotatable together.
That is, at one end of the valve member 31, a notch 31 a whose lower side is opened in the figure is formed, and the dowel pin 32 inserted into the notch 31 a is fixed to the output shaft 3. When the inner surface of the notch 31 contacts the pin 32, the displacement of the valve member 31 in one axial direction is prevented.

A retaining ring 70 is fitted in a circumferential groove 2a on the outer periphery of the input shaft 2 so as to restrict the displacement of the valve member 31 in the other axial direction. When the other end surface of the valve member 31 is in contact with the retaining ring 70, displacement of the valve member 31 in the other axial direction is prevented.

Between the outer periphery of the valve member 31 and the inner periphery of the valve housing 7, the valve member 31 is rotated so that the valve member 31 can be smoothly rotated relative to the input shaft 2 and the valve housing 7. Slight play is provided between the inner periphery and the outer periphery of the input shaft 2, between the inner surface of the notch 31a and the pin 32, and between the other end surface of the valve member 31 and the retaining ring 70. The input shaft 2, the output shaft 3, and the valve housing 7 can be slightly displaced in the radial direction and the axial direction. The play amount may be set to such an extent that the fluctuation of the opening degree of the later-described throttle portions A, B, C, D based on the play does not have a problematic effect on the steering characteristics.

As shown in FIG. 1, the valve housing 7
An inlet port 34 connected to a pump 33, an outlet port 36 connected to a tank 35, a first port 37 connected to one oil chamber 22 of the hydraulic cylinder 20,
A second port 38 connected to the other oil chamber 23 is arranged. As shown in FIG. 3, each port 34, 36, 3
7 and 38 communicate with each other through an oil passage 27 between the input shaft 2 and the valve member 31, and the oil passage 27 is connected to the valve member 31.
And throttle portions A, B, C, and D whose opening degree changes due to relative rotation of the input shaft 2 are formed.

That is, eight first concave portions 50 are formed in the inner periphery of the valve member 31 along the axial direction at equal intervals in the circumferential direction. Eight second concave portions 51 are formed at equal circumferential intervals on the outer periphery of the input shaft 2 so as to face the first concave portion 50 in the circumferential direction. The first recess 50 communicates with the first port 37 via the flow path 53 of the valve member 31;
The one communicating with the second port 38 via the flow passage 54 of the valve member 31 is alternately arranged in the circumferential direction. The second recess 51
Are connected to the inlet port 34 via the flow path 55 of the valve member 31 and the flow path 5 between the inner and outer circumferences of the torsion bar 6 and the input shaft 2 from the lower flow path 52a of the input shaft 2.
2c, the upper channel 52b of the input shaft 2 (FIG. 2,
3) are connected to the outlet port 36 alternately in the circumferential direction. The first recess 50 and the second recess 51
Are defined as aperture portions A, B, C, and D in the circumferential direction.

As shown in FIGS. 1 and 2, a part of the pressure oil discharge passage extending from the upper flow path 52b of the input shaft 2 to the outlet port 36 is formed between the inner periphery of the valve housing 7 and the outer periphery of the input shaft 2. , And the retaining ring 70 is disposed in the space 59.

The hydraulic pressure acting on the hydraulic cylinder 20 is controlled by the change in the degree of opening of the throttles A, B, C, and D. That is, FIG. 3 shows a state where steering is not performed,
In this state, the valve member 31 is at the neutral position with respect to the input shaft 2, the throttle portions A, B, C, and D are fully open, the inlet port 34 and the outlet port 36 communicate with each other, and the hydraulic pressure control from the pump 33 is performed. The oil supplied to the valve 30 returns to the tank 35, and no steering assist force is generated.

The torsion bar 6 is elastically twisted by steering resistance generated by steering to the right, and the valve member 3
When the input shaft 1 and the input shaft 2 rotate relatively in one direction, the first
The relative position between the concave portion 50 and the second concave portion 51 changes, the opening degree of the throttle portion A between the inlet port 34 and the first port 37 increases, and the throttle between the first port 37 and the outlet port 36 increases. The opening of the portion B becomes smaller, the opening of the throttle portion C between the inlet port 34 and the second port 38 becomes smaller, and the opening of the throttle portion D between the second port 38 and the outlet port 36 becomes smaller. growing. Thereby, one oil chamber 2 of the hydraulic cylinder 20 is
2 is supplied with pressurized oil having a pressure corresponding to the magnitude and direction of the steering resistance, and the oil is recirculated from the other oil chamber 23 to the tank 35, and the steering assist force to the right of the vehicle is supplied from the hydraulic cylinder 20. Acts on the rack 16.

When the torsion bar 6 is elastically twisted due to steering resistance generated by steering to the left, the valve member 31 and the input shaft 2 rotate relative to each other in a direction opposite to that in the case where the input shaft 2 is steered to the right. , The opening of the throttle portion B increases, the opening of the throttle portion C increases,
The opening degree of the portion D is reduced. Thereby, the hydraulic cylinder 2
The pressure oil having a pressure corresponding to the magnitude and direction of the steering resistance is supplied to the other oil chamber 23, and the oil is returned from one oil chamber 22 to the tank 35 to assist the steering of the vehicle to the left. A force acts on the rack 16 from the hydraulic cylinder 20.

In a state where the torsion bar 6 is elastically twisted, the torsion bar 6 gives the valve member 31 elasticity to return to the neutral position with respect to the input shaft 2.

As shown in FIG. 2 and FIG.
Is connected to the valve member 31 and the input shaft 2 so as to be elastically deformed by the relative rotation of the valve member 31 with respect to the input shaft 2.

That is, the retaining ring 70 has a pair of ends 70a, 70b separated from each other, and each end 70a, 70b.
hooks 70c, 70d extending inward from b
And a tool insertion hole 70 formed at each end 70a, 70b.
e, 70f, and a pin insertion hole 70g formed at a position farthest from each end 70a, 70b. On the outer periphery of the input shaft 2, a concave portion 2b communicating with the peripheral groove 2a is formed. The hooks 70c and 70d of the retaining ring 70 fitted into the circumferential groove 2a are inserted into the recess 2b. The inner diameter of the retaining ring 70 in the natural state is the circumferential groove 2.
The diameter of the retaining ring 70 fitted in the circumferential groove 2a is reduced elastically in the radial direction, and the hook portions 70c, 70
d is elastically pressed against the inner surface of the concave portion 2b. After being fitted into the circumferential groove 2a, the pin insertion hole 70g
Is inserted into a pin hole 31b formed at the upper end of the valve member 31. Thereby, the retaining ring 7
Numeral 0 is connected to the input shaft 2 and the valve member 31 so as to be elastically deformed in the radial direction by the relative rotation of the valve member 31 with respect to the input shaft 2.

Each hook portion 70c, 7 of the retaining ring 70
The elastic force that presses Od against the inner surface of the concave portion 2b of the input shaft 2 acts in a direction that prevents the valve member 31 from rotating relative to the input shaft 2 from a neutral position. That is,
The retaining ring 70 applies a preload in a direction that restricts the relative rotation of the valve member 31 with respect to the input shaft 2 from the neutral position.

The retaining ring 70 is mounted on the valve member 3.
This is performed after setting the neutral position with respect to the input shaft 2 of the first input shaft. That is, first, the input shaft 2 and the output shaft 3
Is connected to the output shaft 3 via the serration 5, the valve member 31 is connected to the output shaft 3 via the pin 32, and each of the throttle portions A, B, C, and D at the neutral position is connected. After adjusting the relative rotation position between the input shaft 2 and the valve member 31 so that the opening is uniform, an insertion hole for the pin 4 is formed in the torsion bar 6 and the input shaft 2, and the pin 4 is used to connect the torsion bar 6 to the input. Shaft 2
And concatenate. Thereafter, the retaining ring 70 is fitted into the circumferential groove 2a, and the input shaft 2 and the valve member 3 in the neutral position are set.
In a state in which the preload can be applied so that the adjusted relative rotational position of 1 does not change, the pin insertion hole 70g is
Is formed, and the retaining ring 70 is connected to the valve member 31 by the pin 71.

A broken line Q and a solid line P in FIG. 5 indicate a steering torque corresponding to the driver's steering force and the hydraulic cylinder 20.
Shows the relationship with the pressure of the pressurized oil to be applied to the oil pressure, and the broken line Q is an example in which no preload is applied by the retaining ring 70.
The solid line P is an example of a case where a preload is applied by the retaining ring 70. That is, by applying the preload by the retaining ring 70, even if the driver's steering force increases, high-pressure oil is supplied to the steering assist force generating hydraulic cylinder 20 until the preload applied by the retaining ring 70 is released. Therefore, the stability of the vehicle when traveling straight at a high speed can be improved. Further, at the time of stationary steering or low-speed steering, the pressure of the hydraulic oil applied to the hydraulic cylinder 20 by releasing the preload is increased, and a sufficient steering assist force can be obtained. By changing the preload, any characteristic can be obtained.

According to the above configuration, the preload is reduced by the retaining ring 70.
By applying the above, a dedicated member for applying the preload is not required, so that it is possible to prevent an increase in the number of parts, the number of assembly steps, and the manufacturing cost. Also, the retaining ring 70
Is disposed in the space 59 between the inner periphery of the valve housing 7 and the outer periphery of the input shaft 2 which constitutes a part of the pressure oil discharge path. Can be prevented.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the input shaft is the first shaft and the output shaft is the second shaft, but the input shaft may be the second shaft and the output shaft may be the first shaft.

[0034]

According to the present invention, when used in a hydraulic power steering system, the hydraulic control that can improve the stability of a vehicle when traveling straight without increasing the number of parts, the number of assembly steps, the manufacturing cost, and the size of the apparatus. Can provide valve.

[0035]

Comparative Example A comparative example of the present invention will be described with reference to FIG.
The same parts as those in the above embodiment are denoted by the same reference numerals. The difference between this comparative example and the above embodiment is that knurls, serrations and the like are formed on the outer periphery of the dowel pin 32 ′ fixed to the output shaft 3, and the pin 32 ′ is cut into the inner surface of the notch 31 a of the valve member 31. As a result, it is press-fitted into the notch 31a. Others are the same as the above embodiment. In this comparative example, since the valve member 31 cannot be relatively displaced with respect to the output shaft 3, high-precision machining is required to smoothly rotate the valve member 31 relative to the input shaft 2 and the valve housing 7. Required, increasing costs.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a hydraulic power steering device according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of the hydraulic control valve according to the embodiment of the present invention.

FIG. 3 is a sectional view taken along line III-III of FIG. 1;

FIG. 4 is a sectional view taken along line IV-IV of FIG. 2;

FIG. 5 is a diagram showing a relationship between a steering torque and a hydraulic pressure for generating a steering assist force of the hydraulic power steering device according to the embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a comparative example.

[Explanation of symbols]

 2 input shaft 3 output shaft 6 torsion bar 7 valve housing 20 hydraulic cylinder 31 valve member 59 space 70 retaining ring A, B, C, D throttle section

Claims (3)

[Claims] 1. A housing, a first shaft, a second shaft, a torsion bar for connecting the first shaft and the second shaft elastically and relatively rotatably around a coaxial center, and an inner periphery of the housing and a second shaft. Between the outer circumference of one shaft,
A cylindrical valve member fitted to the housing and the first shaft so as to be rotatable relative to each other, and provided in an oil passage between the first shaft and the valve member by the relative rotation of the first shaft and the valve member. A throttle portion is formed so that the opening degree changes, and the valve member is rotatable along with the second shaft so that the displacement in one axial direction is restricted and the displacement in the other axial direction is allowed. A hydraulic control valve, wherein the retaining ring is fitted around the outer periphery of the first shaft so as to regulate the displacement of the valve member in the other axial direction; The valve member is connected to the first shaft so as to be elastically deformed by the relative rotation, and the retaining ring can apply a preload in a direction for restricting the relative rotation of the valve member from the neutral position with respect to the first shaft. Hydraulic control valve according to claim Rukoto. 2. The hydraulic control valve according to claim 1, wherein the retaining ring is disposed in a space between an inner periphery of the housing and an outer periphery of the first shaft, which forms a part of a pressure oil discharge passage. 3. The hydraulic control valve according to claim 1, wherein the hydraulic pressure acting on the hydraulic actuator for generating a steering assist force of the hydraulic power steering device of the vehicle can be controlled by changing the opening degree of the throttle.