JP2927652B2 - Hydraulic power steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power steering apparatus having a control valve for controlling a steering assist force according to a relative rotation amount between an input shaft and an output shaft.

[0002]

2. Description of the Related Art An input shaft which is rotated by steering, an output shaft which is coaxially and relatively rotatably connected to the input shaft, rotates together with one of the input shaft and the output shaft, and rotates relative to the other. 2. Description of the Related Art A hydraulic power steering apparatus that includes a hydraulic control valve having a valve member and generates a steering assist force in accordance with the relative rotation amount of the input shaft and the output shaft with respect to the valve member has been conventionally used.

The relative position of the input shaft and the output shaft relative to the valve member in the circumferential direction is equal in steering characteristics when steering left and right and when steering left and right, so that no steering resistance acts. In the neutral state, it is necessary to keep a fixed position.

For this reason, when the hydraulic power steering apparatus is assembled, if the circumferential relative position of the other of the input shaft and the output shaft with respect to the valve member in the neutral state is deviated from a fixed position, a means for correcting the deviation is provided. A hydraulic power steering device provided with the same has been proposed. For example, in Japanese Patent Publication No. 63-51907, an input shaft and an output shaft are surrounded by a ring-shaped spring having a groove, and pins are inserted into the input shaft and the output shaft, respectively. A hydraulic power steering device is disclosed in which each pin is positioned in such a manner that one pin abuts against one of the opposing ends of the split groove of the spring and the other pin abuts on the other of the opposing ends of the split groove of the spring. Have been. According to this conventional structure, when the other relative position of the input shaft and the output shaft with respect to the valve member in the circumferential direction is deviated from the fixed position, the relative position of one pin with respect to the other pin in the circumferential direction is corresponding to the amount of the displacement. By shifting the position, the output shaft can be relatively rotated with respect to the input shaft by the elastic force of the spring corresponding to the shift amount.

[0005]

However, in the above conventional example, in order to change the circumferential relative positions of the pins respectively inserted into the input shaft and the output shaft, the other of the input shaft and the output shaft with respect to the valve member is changed. It is necessary to determine the position of the pin insertion hole in accordance with the amount of displacement of the relative position in the circumferential direction, and thereafter to machine the pin insertion hole. Therefore, the position changing operation is extremely difficult, the work efficiency is low, and the manufacturing cost is increased.

An object of the present invention is to provide a hydraulic power steering apparatus that can solve the above-mentioned problems of the prior art.

[0007]

SUMMARY OF THE INVENTION The present invention provides an input shaft which is rotated by steering, an output shaft which is coaxially and relatively rotatably connected to the input shaft, and which rotates together with one of the input shaft and the output shaft. And a hydraulic power steering device having a hydraulic control valve having a valve member that rotates relative to the other, and generating a steering assist force according to the relative rotation amount of the other of the input shaft and the output shaft with respect to the valve member.
A neutral position adjusting member capable of changing the position along the radial direction of the input / output shaft is provided, and the other relative position of the input shaft and the output shaft with respect to the valve member in the circumferential direction is changed according to the amount of radial displacement of the neutral position adjusting member. A means for changing the position is provided.

[0008]

According to the configuration of the present invention, by displacing the neutral position adjusting member in the radial direction, it is possible to change the other circumferential position of the input shaft and the output shaft with respect to the valve member in accordance with the amount of displacement. it can. Therefore, in the neutral state, when the other circumferential relative position of the input shaft and the output shaft with respect to the valve member is displaced from the fixed position, by displacing the neutral position adjusting member in the radial direction corresponding to the amount of displacement, The circumferential relative position can be corrected to a fixed position.

[0009]

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

A rack and pinion type hydraulic power steering apparatus 1 shown in FIG. 1 has a cylindrical input shaft 2 connected to a steering wheel (not shown) of a vehicle, and an output shaft 3 coaxially connected to the input shaft 2. The input shaft 2 and the output shaft 3 are relatively rotated by the torsion of the torsion bar 6. The lower end of the input shaft 2 is smaller in diameter than the upper portion.
A concave portion 3a is formed at the upper end of the output shaft 3 opposite to the lower end of the output shaft. The lower end of the input shaft 2 is fitted in the recess 3a with the bearing 1
2 are fitted. A torsion bar 6 is inserted into the input shaft 2 and the output shaft 3.
The upper end is connected to the input shaft 2 via a pin 4, and the lower end is connected to the output shaft 3 via a serration 5.

The input shaft 2 is rotatably supported by a valve housing 7 via a bearing 8. The output shaft 3 has a pair of bearings 1 mounted on a rack housing 9.
It is rotatably supported via 0,11. A pinion 15 is formed on the output shaft 3, and a rack 16 meshing with the pinion 15 is supported by a support yoke 40.
Steering wheels (not shown) are connected to the rack 16. Thus, the rotation of the input shaft 2 due to the steering is transmitted to the pinion 15 via the torsion bar 6, and the rotation of the pinion 15 causes the rack 16 to move in the vehicle width direction.
The vehicle is steered by the movement of the rack 16.

A hydraulic cylinder 20 is provided as a hydraulic actuator for applying a steering assist force. The hydraulic cylinder 20 includes a cylinder tube configured by the rack housing 9 and a piston 21 integrated with the rack 16. Hydraulic control valves 30 for supplying hydraulic oil in accordance with the steering direction and the steering resistance are provided in oil chambers 22 and 23 partitioned by the piston 21.

The control valve 30 is inserted into the valve housing 7 via a plurality of upper and lower seal rings 25 so as to be relatively rotatable, and is fitted to the outer periphery of the input shaft 2 so as to be relatively rotatable. A valve member 31 is provided. The valve member 31 is fitted around the output shaft 3 via a pin (neutral position adjusting member) 32 so as to rotate together therewith.

The valve housing 7 has an inlet port 34 connected to a pump 33, an outlet port 36 connected to a tank 35, and 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. The ports 34, 36, 37, and 38 communicate with each other through an oil passage between the input shaft 2 and the valve member 31, and the throttle formed in the oil passage is connected to the input shaft 2 due to the torsion bar 6 being twisted. The opening is adjusted by the relative rotation between the valve member 31 and the valve member 31.

That is, as shown in FIG.
The first concave portions 50 along the axial direction on the inner periphery of the
It is formed at several places. Eight second concave portions 51 are formed at equal circumferential intervals on the outer periphery of the input shaft 2 so as to oppose the first concave portions 50 in the circumferential direction. The first recess 50 is connected to the first port 3 through a flow path 53 formed in the valve member 31.
7 and a flow path 54 formed in the valve member 31.
Are alternately arranged in the circumferential direction in parallel with the second port 38. The second recess 51 is formed between the torsion bar 6 and the input shaft 2 through the flow passage 52 a formed below the input shaft 2 and the one communicating with the inlet port 34 via the flow passage 55 formed in the valve member 31. The one that communicates with the outlet port 36 from the flow path 52b formed above the input shaft 2 via the flow path 52c between the inner and outer circumferences is alternately arranged in the circumferential direction. Apertures A, B, C, and D are defined between circumferential edges of the first recess 50 along the axial direction and the second recess 51 along the axial direction.

FIG. 2 shows a neutral state where steering is not being performed and steering resistance is not acting.
The circumferential intervals of D are equal to each other. In this neutral state, the inlet port 34 and the outlet port 36 communicate with each other, the oil flowing into the control valve 30 from the pump 33 returns to the tank 35, and no steering assist force is generated. When the torsion bar 6 is twisted due to steering resistance generated by steering to the left or right, and the valve member 31 and the input shaft 2 rotate relative to each other, the circumferential relative position between the first concave portion 50 and the second concave portion 51 changes, and The opening of the throttle A between the port 34 and the first port 37 is increased, the opening of the throttle B between the first port 37 and the outlet 36 is reduced, and the inlet 34 and the second port 37 are closed. 38, the opening degree of the throttle portion C between the second port 38 and the outlet port 36 increases. Thereby, the hydraulic cylinder 2
0 is supplied to one of the oil chambers 22 with pressure corresponding to the steering direction and the steering resistance.
The oil flows back to 5, and a steering assist force to the left or right of the vehicle acts on the rack 16 from the piston 21. When the steering is performed to the left or right, the valve member 31 and the input shaft 2 relatively rotate in a direction opposite to that in the case where the steering is performed to the left or right, the opening of the throttle A is reduced, the opening of the throttle B is increased, and the throttle is increased. The degree of opening of the portion C increases, and the degree of opening of the throttle portion D decreases, so that the steering assist force to the other side of the vehicle acts on the rack 16 from the piston 21.

The hydraulic oil of the hydraulic cylinder 20 is pump 3
While returning to the tank 35 from the valve housing 7, the valve housing 7
The oil seal 60 is interposed between the outer circumference of the input shaft 2 and the upper inner circumference of the valve housing 7, and is interposed between the outer circumference of the output shaft 3 and the lower inner circumference of the valve housing 7 in order to prevent leakage. An oil seal 61 is provided between the upper outer periphery of the torsion bar 6 and the upper inner periphery of the input shaft 2.

In the above neutral state, each of the throttle portions A, B,
If the circumferential intervals of C and D are not equal to each other, the steering characteristics will not be the same when steering left or right and when steering left and right. Therefore, the circumferential relative position of the input shaft 2 with respect to the valve member 31 in the neutral state is
If the apertures A, B, C, and D are not at a fixed position where the circumferential intervals are equal to each other, a means for correcting a deviation from the fixed position is provided. That is, as shown in FIGS. 3 to 5, the pin 32 for fixing the valve member 31 to the output shaft 3 has a head 32 a at one end and a pin formed on the output shaft 3 along a radial direction. Insertion hole 41 and valve member 31
Notch 4 with a semicircular top with open lower end formed at the lower end of
2 and is inserted. The other end of the pin 32 is the output shaft 3
And the head 32 of the pin 32
a contacts the inner surface 42 a of the notch 42 of the valve member 31. The inner surface 42a of the notch 42 is inclined along the axial direction of the input and output shafts 2 and 3 with respect to a plane including the diameter of the input and output shafts 2 and 3 (inclination angle α in FIG. 3).

As a result, when the pin 32 is displaced in the radial direction by changing the amount of press-fit into the pin insertion hole 41, the head 32a of the pin 32 outputs the valve member 31 via the inner surface 42a of the notch 42. Since the rotation is performed in the circumferential direction with respect to the shaft 3, the relative position of the input shaft 2 in the circumferential direction with respect to the valve member 31 changes according to the amount of radial displacement of the pin 32. The downward movement of the valve member 31 is restricted by the head 32a of the pin 32, and the upward movement is performed by the ring 66 fitted to the input shaft 2.
Regulated by

According to the above configuration, by displacing the pin 32 in the radial direction, the circumferential relative position of the input shaft 2 with respect to the valve member 31 can be changed in accordance with the amount of displacement. If the relative position of the input shaft 2 in the circumferential direction with respect to the member 31 is displaced from the predetermined position, the pin 32 is displaced in the radial direction in accordance with the amount of displacement, thereby keeping the relative position in the circumferential direction constant. Can be. That is, the shift of the relative position of the input shaft 2 in the circumferential direction with respect to the valve member 31 in the neutral state can be easily and efficiently corrected, and the manufacturing cost can be reduced.

As shown in FIG. 3, a pair of recesses 70 which are 180 ° apart from each other in the circumferential direction are formed on the outer periphery of the input shaft 2, and a spring 71 and a ball 72 are inserted into each recess 70.
The spring 71 applies an elastic force along the radial direction of the input / output shafts 2 and 3 to the ball 72, and the elastic force
2 presses the inner peripheral surface of the output shaft 3. In addition, a pair of recesses 7 that are 180 ° apart from each other in the circumferential direction on the inner circumference of the output shaft 3.
7 are formed. The ball 72 contacts the center of the recess 77 in the circumferential direction in a neutral state where steering resistance does not act. As shown in FIG. 6, the inner surface of the concave portion 77 is a curved surface, and the radius of curvature r has a maximum value R at the center in the circumferential direction, and gradually decreases toward both ends in the circumferential direction. As a result, when the ball 72 presses a position offset toward both ends in the circumferential direction from the center between the circumferential directions of the inner surface of the concave portion 77, the spring 71
Since the pressing force Fa based on the elastic force is along the radial direction of the input and output shafts 2 and 3, the pressing force Fa is divided into a component force Fb in the normal direction of the inner surface of the concave portion 70 and a component force Fc in the tangential direction. The tangential component force Fc is a force for rotating the input shaft 2 with respect to the output shaft 3 to make the input shaft 2 neutral. As a result, a force acting to hold the steering wheel in the straight traveling position at the time of traveling acts, improving traveling stability during straight traveling, and smoothly moving the steering handle to the straight traveling position when traveling straight after cornering. You can go back.

The present invention is not limited to the above embodiment. For example, FIGS. 7 to 9 show that the relative position of the input shaft 2 with respect to the valve member 31 in the circumferential direction in the neutral state is determined by each of the throttle portions A, B, and C. A and D show a modification of the means for correcting a deviation from the fixed position when the circumferential distances are not equal to each other. That is, the pin 32 ′ for fixing the valve member 31 to the output shaft 3 and the notch 42 ′ of the valve member 31 are conventional ones, and merely have a function of fixing the valve member 31 to the output shaft 3. Instead, a spring 80 and a pair of pins (neutral position adjusting members) 81 and 82 are provided. One of the pins 81 has a head 81a at one end, and the other end has a through hole 8 having a diameter larger than that of the pin 81 formed on the output shaft 3.
7 and is press-fitted into a pin through hole 88 formed in the input shaft 2 along the radial direction. The other pin 82 has a head 82a at one end, and the other end is press-fitted into a pin insertion hole 89 formed on the output shaft 3 along a radial direction. The spring 80 has a C-shaped ring shape having a split groove 80a, is fitted in a peripheral groove 83 formed on the outer periphery of the upper end of the output shaft 3, and extends upward from each of the opposed ends of the split groove 80a. Pin receiving portions 85 and 86 are provided. Both pin receiving part 8
One end of each of the pins 81 and 82 is disposed between the pins 5 and 86, and the heads 81a and 82a of the pins 81 and 82 are in contact with the inner surfaces 85a and 86a of the pin receiving portions 85 and 86. The inner surfaces 85a, 86a of the pin receiving portions 85, 86 are inclined along the axial direction of the input / output shafts 2, 3 with respect to a surface including the diameter of the input / output shafts 2, 3 (inclination angle β in FIG. 9).

Accordingly, when the one pin 81 is displaced in the radial direction by changing the amount of press-fit into the pin through hole 88,
The head 81a of the pin 81 presses the spring 80 in the circumferential direction via the inner surface 85a of one pin receiving portion 85 according to the amount of radial displacement, so that the spring 80 passes through the inner surface 86a of the other pin receiving portion 86. The head 82a of the other pin 82 is pushed in the circumferential direction. As a result, the input shaft 2 relatively rotates in one direction with respect to the output shaft 3, so that the circumferential relative position of the input shaft 2 with respect to the valve member 31 changes to one circumferential direction in accordance with the radial displacement of one pin 81. . When the other pin 82 is displaced in the radial direction by changing the amount of press-fitting into the pin insertion hole 89, the head 82a of the pin 82 is moved to the inner surface of the one pin receiving portion 85 according to the amount of radial displacement. 85a is pressed in the circumferential direction through the spring 85a.
5, the head 81a of one of the pins 81 is pressed in the circumferential direction via the inner surface 85a. As a result, the input shaft 2 rotates relative to the output shaft 3 in the other direction.
Is changed to the other circumferential direction in accordance with the amount of radial displacement of the other pin 82. That is, the press-fitting operation of one pin 81 changes the circumferential relative position of the input shaft 2 with respect to the valve member 31 to one circumferential direction in accordance with the radial displacement of one pin 81, and the press-fitting action of the other pin 82 causes the valve to move. Member 3
1 relative to the other pin 82
Changes in the other circumferential direction in accordance with the amount of radial displacement. Other parts are the same as those in the above embodiment, and the same parts are indicated by the same reference numerals.

FIG. 10 shows each recess 77 in the above embodiment.
FIG. 11 shows a configuration in which a piston 95 having a spherical tip is used in place of the ball 72 that presses the ball 72, and FIG. 11 replaces the ball 71 that presses each recess 77 with the spring 71 that applies elastic force for pressing the recess. Is a leaf spring 9 with a curved surface
6 is shown.

Although the valve member 31 is fixed to the output shaft 3 in the above embodiment, it may be fixed to the input shaft 2 so as to rotate relative to the output shaft 3. In addition, the present invention can be applied to, for example, a ball screw type hydraulic power steering device other than the rack and pinion type.

[0026]

According to the hydraulic power steering apparatus of the present invention, the deviation of the other relative position of the input shaft and the output shaft in the circumferential direction with respect to the valve member in the neutral state can be easily and efficiently corrected to reduce the manufacturing cost. can do.

[Brief description of the drawings]

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

FIG. 2 is a sectional view taken along line II-II of FIG.

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. 3;

FIG. 5 is a view taken in the direction of the arrow V in FIG. 3;

FIG. 6 is a diagram illustrating the operation of the hydraulic power steering device according to the embodiment of the present invention.

FIG. 7 is a partially broken front view of a main part of a modification of the present invention.

FIG. 8 is a partially broken side view of a main part of a modification of the present invention.

FIG. 9 is a sectional view taken along line IX-IX of FIG. 7;

FIG. 10 is a partial plan sectional view of a modification of the present invention.

FIG. 11 is a partial plan sectional view of a modification of the present invention.

[Explanation of symbols]

 2 input shaft 3 output shaft 30 control valve 31 valve member 32, 81, 82 pin (neutral position adjusting member)

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-91366 (JP, A) JP-A-57-198171 (JP, A) JP-A-7-144651 (JP, A) JP-A-5-191465 345571 (JP, A) JP-A-5-319281 (JP, A) JP-A-58-108965 (JP, U) JP-A-56-108966 (JP, U) JP-A-58-115465 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B62D 5/083

Claims (1)

(57) [Claims] An input shaft rotated by steering, an output shaft coaxially and relatively rotatably connected to the input shaft, and rotating together with one of the input shaft and the output shaft and rotating relative to the other. A hydraulic control valve having a valve member, wherein the hydraulic power steering device generates a steering assist force in accordance with the relative rotation of the other of the input shaft and the output shaft with respect to the valve member. And a means for changing the other circumferential relative position of the input shaft and the output shaft with respect to the valve member in accordance with the amount of radial displacement of the neutral position adjusting member. A hydraulic power steering device.