JPH115543A - Power steering device for automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To change tilting force and tilting angle of a front wheel for rotational force and rotational angle of a steering wheel by changing the radii of a steering wheel side drum and a steering side drum so that the sum of the radii at the axial corresponding location may be constant. SOLUTION: A steering wheel side drum 7 is formed into an hourglass shape in which a diameter d0 at the center part gradually becomes smaller than a diameter d1 at both the end parts and a steering side drum 8 is formed into a bass drum shape in which the diameter d1 at the center part gradually becomes larger than the diameter d0 at both the end parts. As a result, when an inner cable 6 is wound in the vicinity of the end parts of both the drums 7, 8, tilting force and tilting angle of a front wheel in relation to rotational force and rotational angle of a steering wheel 1 become larger than conventional ones because the radius of a part on which the inner cable 6 of the steering wheel side drum 7 is wound becomes larger than the radius of the steering side drum 8. When the inner cable 6 is wound in the vicinity of the center part, tilting force and tilting angle of the front wheel become smaller because the radius of the steering wheel side drum 7 becomes smaller than the steering side drum 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power steering apparatus for an automobile using two control cables and a power cylinder that apply a tensile force to an inner cable, and more particularly to a tilting power of a front wheel with respect to a turning force of a steering wheel and a steering wheel. The present invention relates to a power steering apparatus for an automobile, in which a tilt angle of a front wheel with respect to a rotation angle of a vehicle can be changed.

[0002]

2. Description of the Related Art The applicant of the present application discloses a power cylinder having a piston rod connected to a front wheel via a steering link mechanism at both ends, and is supplied to the power cylinder and simultaneously discharged from the power cylinder. A rotary control valve for controlling the direction of pressure oil, a steering drum connected to the rotor of the control valve,
A handle-side drum connected to the handle and an inner cable slidably inserted into a flexible outer tube are provided so that a pulling force acts alternately when the handle-side drum rotates in an alternate direction. A patent application was filed for a power steering device for an automobile including two control cables wound around a helical groove, which was published as Japanese Patent Application Laid-Open No. 8-2431.

[0003]

The required performance of an automobile varies depending on the type of vehicle, and it is sometimes required to change the tilting power of the front wheels with respect to the turning force of the steering wheel and the tilt angle of the front wheels with respect to the turning angle of the steering wheel.

However, the invention described in the above publication has a problem that the tilting power of the front wheels with respect to the turning force of the steering wheel and the tilting angle of the front wheels with respect to the turning angle of the steering wheel cannot be changed.

[0005]

According to the present invention, as a means for solving such a problem, the radius of both drums is set such that the sum of the radii of the two drums at the corresponding position in the axial direction is constant. Therefore, the tilting power and the tilting angle of the front wheel with respect to the turning force and the turning angle of the steering wheel can be changed while keeping the tension of the inner cable constant. If the drum is shaped like a drum and the steering drum is shaped like a drum, when the inner cable is wound near the ends of both drums, the radius of the part where the inner cable of the handle drum is wound is larger than that on the steering side. The tilting power and tilting angle of the front wheels with respect to the turning force and the turning angle of the steering wheel become larger than before, and the inner cable is wound around the center of both drums. Sometimes, since the radius of the portion wound around the inner cable of the handle-side drum is smaller than the steering side, front tilting force and tilt angle of the relative rotational force and rotation angle of the steering wheel becomes smaller than before.

If the handle-side drum is drum-shaped and the steering-side drum is drum-shaped, the steering characteristics are reversed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a handle, which is rotatably supported by a case 2 attached to a vehicle body.

At the front steering position of the vehicle body, the case 2
A case 2 having the same structure as that described above is disposed between the two cases 2 and 2, and two flexible control cables in which the end of the outer tube 5 is fixed to the cases 2 and 2 by the cylindrical fixture 3. 4 are routed.

The control cable 4 is a cable in which an inner cable 6 is slidably inserted into an outer tube 5. As shown in FIGS. 2 and 3, the cylindrical fixture 3 is crimped to the end of the outer tube 5. A male screw 11 formed on the outer periphery thereof is screwed into a nut 12 fixed to the case 2, and the length of the control cable 4 is adjusted by the rotation of the cylindrical fixture 3, so that the lock nut 13 is formed.
The inner cable 6
Are wound around the spiral grooves 7a, 8a of the steering-side drum 7 and the handle-side drum 8, which are rotatably supported in the case 2, and the winding of two inner cables 6, as shown in FIGS. The directions are opposite to each other, and the terminals 6 a are fixed to both end faces of the drums 7 and 8.

The rotating shaft 7b of the drum 7 on the handle side projects from one surface of the case 2 and is connected to the rotating shaft of the handle 1, and the rotating shaft 8b of the steering drum 8 is connected to a rotor 10 of a rotary valve 9 to be described later. Have been.

In FIG. 1, reference numeral 14 denotes a cylinder tube 1
5. A power cylinder in which a piston 16 is slidably fitted to a piston rod 5, and a piston rod 17 fixed to the piston 16.
A tie rod 20 is connected to both ends via ball joints 19, and the tie rod 20 is connected to a front wheel a via a knuckle arm (not shown).

In the present invention, the tie rod 20, the knuckle arm and the like are collectively referred to as a steering link mechanism.

A pinion 21 is fixed to the rotor 10 of the rotary valve 9 and meshes with the rack 18.

A supply port 22 of the rotary valve 9 is connected to a hydraulic pump (not shown), and a discharge port 23 is connected to a tank (not shown).
The pipes 4 and 25 are connected to two ports 26 and 27 of the cylinder tube 15 by pipes 28 and 29. When the rotor 10 rotates in one direction, pressure oil is supplied to one side of the piston 16 and discharged from the other side. When rotated in the other direction, the pressure oil is supplied to the other side of the piston 16 and is discharged from one side, so that the piston 16 operates together with the piston rod 17.

What has been described above is a known structure described in the above-mentioned publication and operates as follows.

When the handle 1 is rotated in one direction, the drum 2 wound around the handle-side drum 7 and the steering-side drum 8 is rotated.
One of the inner cables 6 of the control cable 4 is wound on the drum 7 on the handle 1 side, and the inner cable 6 is fed out from the drum 8 on the steering side, so that the drum 8 and the rotating shaft 8b rotate in one direction. I do.

At this time, the other control cable 4
The inner cable 6 is drawn out from the drum 7 on the steering wheel side and wound up on the drum 8 on the steering side.

When the handle 1 is rotated in the other direction, the drum 8 on the steering side and its rotating shaft 8b rotate in the other direction by the same operation.

When the rotating shaft 8b of the steering drum 8 rotates in one direction, the rotor 10 connected thereto rotates in the same direction, and the engagement between the pinion 21 and the rack 18 causes the piston rod 17 to operate in one direction. At this time, rotation of the rotor 10 causes pressure oil to be supplied from one of the ports 24, 25 of the rotary valve 9 to one of the ports 26, 27 of the power cylinder 14, and the piston rod 17 moves in the same direction as above. It operates, and the wheel a faces one side via the steering link mechanism.

When the rotating shaft 8b of the drum 8 on the steering side rotates in the other direction, the same operation causes the wheel a to face the other direction.

In this embodiment, as shown in FIG. 6, the handle-side drum 7 has a drum shape in which the diameter d _{0 at the} center is gradually smaller than the diameter d _{1 at} both ends, and the drum 7 on the steering side is provided. 8 has a drum shape in which the diameter d _{1 at the} center is gradually larger than the diameter d _{0 at} both ends.

Therefore, as shown by a solid line in FIG. 6, the inner cable 6 is connected to the spiral groove 7 at the center of both drums 7 and 8.
When the rotating shaft 7b is rotated in one direction or the other direction by the handle 1 in the neutral position where the inner cable 6 is wound or unreeled at the positions 8a and 8a, one of the inner cables 6 is wound around the spiral groove 7a of the drum 7. Since the other inner cable 6 is fed out from the spiral groove 7a, the winding position and the feeding position with respect to the drums 7 and 8 change upward or downward as shown by a chain line in FIG.

As described above, if the handle-side drum 7 is shaped like a drum and the steering-side drum 8 is shaped like a drum, when the inner cable 6 is wound around the ends of both drums 7, 8, the handle-side drum 7 Is larger than the radius on the steering drum 8 side, so that the tilting power and tilting angle of the front wheel a with respect to the turning force and the turning angle of the steering wheel 1 are larger than those of the conventional cylindrical drum. When the inner cable 6 is wound around the center of both drums 7 and 8, the radius of the portion of the handle-side drum 7 where the inner cable 6 is wound becomes smaller than that of the steering-side drum 8. The tilting power and tilting angle of the front wheel a for one rotation force and one rotation angle are smaller than those of the conventional cylindrical drum.

This is as shown in FIGS.

When the handle-side drum is drum-shaped and the steering-side drum is drum-shaped, the steering characteristics are reversed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an outline of an embodiment of the present invention.

FIG. 2 is a perspective view of a main part on the handle side according to the present invention.

FIG. 3 is a perspective view of a main part on a steering side of the present invention.

FIG. 4 is a perspective view showing a state in which the inner cable 6 is wound around the handle-side drum 7.

FIG. 5 is a perspective view showing a state in which the inner cable 6 is wound around the steering drum 8;

FIG. 6 is an explanatory diagram showing a state in which the inner cable 6 is wound around both drums 7 and 8;

FIG. 7 is a graph showing a change in tilting power of a front wheel with respect to a steering wheel rotation angle.

FIG. 8 is a graph showing a change in a tilt angle of a front wheel with respect to a steering wheel rotation angle.

[Explanation of symbols]

 1: Handle 2: Case 3: Cylindrical fixing tool 4: Control cable 5: Outer tube 6: Inner cable 7, 8: Drum 7a, 8a: Spiral groove 7b, 8b: Rotating shaft 9: Control valve 10: Rotor 14: Power cylinder 17: Piston rod

Claims (2)

[Claims] 1. A power cylinder having a piston rod connected at both ends to a front wheel via a steering link mechanism, and a direction control of pressure oil supplied to the power cylinder and simultaneously discharged from the power cylinder. A rotary control valve, a steering-side drum connected to a rotation shaft of a rotor of the control valve, a handle-side drum connected to a rotation shaft of a handle, and sliding freely in an outer tube having flexibility. Power steering apparatus for a vehicle, comprising: two control cables wound around helical grooves of both drums such that an inner cable inserted through the inner circumferential surface of the handle drum alternately exerts a tensile force when the handle-side drum rotates in an alternate direction. Wherein the radius of the two drums is such that the sum of the radii of the two drums at the corresponding position in the axial direction is constant. A power steering apparatus for an automobile, characterized in that the power steering apparatus changes in the axial direction. 2. One of the two drums has a drum shape in which the diameter of the central portion is gradually larger than that of both ends, and the other has a drum shape in which the diameter of the central portion is gradually smaller than the diameters of both ends. An automotive power steering apparatus according to claim 1.