JPS6340719B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power steering device for a vehicle.

2. Description of the Related Art In order to reduce fatigue associated with steering operations in automobiles, power steering devices are known that use hydraulic pressure to power assist steering operations.

This power steering device generally has a problem in that it has a complicated structure, poor productivity, and is expensive.

What is shown in FIG. 1 is a power steering device already proposed by the present applicant (Japanese Patent Application No. 135754/1982) in order to simplify the control valve part in particular. As shown,
A stub shaft 1 to which input rotation is transmitted; a worm shaft 4 screwed into a piston 3 connected to the stub shaft 1 via a torsion bar 2; A control valve 6 is provided for selectively supplying pressure oil to the left and right cylinder chambers 5A, 5B.

This control valve 6 consists of a valve rotor 7 and a valve sleeve 8, which are connected to either the stub shaft 1 or the worm shaft 4, and the rotating sliding surfaces of both form a conical surface centered on the rotation axis. ing.

The groove bottoms of the groove portions 9 and 10 formed on these conical surfaces are approximately parallel to the rotation axis, while the base end of the wormshaft 4 that is connected to either the valve rotor 7 or the sleeve 8 has a housing. A thrust bearing 12 is integrally formed with the thrust bearing 11, which is fixed on both sides in the axial direction.

Since the valve sleeve 8 and the valve rotor 7 have conical sliding surfaces, it is possible to integrally mold them using precision casting, forging, or sintered metal, especially by die-cutting in the axial direction. It has the advantage of not requiring any subsequent machining since no burrs are generated from the mating surfaces unique to split molds.

However, in such a conventional power steering device, the valve housing 11B constricts inward at the outer end so as to enclose the control valve 6, and rotatably supports the stub shaft 1 via the bearing 13. In order to disassemble the control valve 6, the valve housing 11B and the like must be removed, making disassembly and assembly very difficult. Furthermore, since the control valve 6 has a conical sliding surface, a thrust force acts on the valve sleeve 8 to the left in the figure, and a thrust force acts on the valve rotor 7 to the left and right. It was difficult to adjust the gap between the valve sleeve 8 and the rotor 7, and assembly efficiency during production was also poor.

Therefore, the present invention solves the above problems by making the inner periphery of the valve housing larger in diameter than the outer periphery of the valve sleeve, and by screwing a bearing cap that rotatably supports the stub shaft onto the inner periphery of the outer end. It aims to solve the problem.

Hereinafter, this invention will be explained based on the drawings.

In FIG. 2, a torsion bar 2 connected with a pin 20 is coaxially disposed at the tip of a starve shaft 1 connected to a steering wheel.
This torsion bar 2 is inserted into a hollow worm shaft 4, and its tip is connected to a pin 21 (first
(see figure) to connect with the wormshaft 4.

Therefore, when a rotational input is applied to the stub shaft 1, the wormshaft 4 rotates in the same direction while twisting the torsion bar 2.

A rotary control valve 6 that controls the supply of pressure oil to the cylinder chamber 5A or 5B to reduce steering operation force.
is arranged inside the valve housing 11B.

A valve sleeve 8 of a control valve 6 is fitted into a flange 22 at the end of the wormshaft 4, and is prevented from rotating by a pin 23.

Therefore, the valve sleeve 8 rotates at the same time as the wormshaft 4.

On the other hand, the valve rotor 7 disposed on the inner surface of the valve sleeve 8 is commonly connected to the stub shaft 1 and the torsion bar 2 by a pin 20 that connects them.

That is, one end of the pin 20 is inserted into an axially extending groove 24 formed on the inner periphery of the valve rotor 7, and the valve rotor 7 is rotated at the same time as the stub shaft 1.

The rotating sliding contact surface between the valve sleeve 8 and the valve rotor 7 is formed into a conical surface with the axis of the stub shaft 1 as the center of rotation.

Incidentally, one of the major features of the present invention is that the inner periphery of the opening on the steering wheel side of the valve housing 11B, that is, the right side in the figure, is formed to have a larger diameter than the outer periphery of the control valve 6. An annular cap 26 is screwed through a threaded part 25 provided on the inner periphery of the shaft, and the stub shaft 1 is rotatably supported through a bearing 13 arranged inside the cap 26. The oil chamber 28 is oil-tightly sealed.

There is also a lock nut 4 on the outside of the cap 26.
0 is fitted into the cap 26, and a thrust bearing 30 that slides into contact with the end surface of the valve rotor 7 is inserted into the cap 26.
As a result, a thrust force acting on the valve rotor 7 in the right direction in the figure is applied.

Therefore, the valve rotor 7 can be held down by the cap 26, and the holding force and positioning are determined by the threaded portion 25.
Since it can be freely adjusted, the gap between the valve sleeve 8 and the rotor 7 can be easily adjusted even if there is a machining dimensional error in the component parts such as the control valve 6.

In particular, in this invention, the valve housing 11B
Since the inner periphery of the opening of the control valve 6 is formed to have a larger diameter than the outer periphery of the control valve 6, after removing the cap 26, the valve housing 11B
With the control valve 6 still attached to the main body,
The valve sleeve 8 and valve rotor 7 can be pulled out from the right direction in the figure. As a result, it is possible to obtain the effect that the dividing and attaching work becomes significantly easier.

As shown in FIGS. 3A and 3B, instead of receiving the thrust force acting on the valve rotor 7 with the cap 26, a threaded ring (gap adjustment member) 29A or a snap screw is screwed onto the outer periphery of the stub shaft 1. Even if it is received by the attached ring 29B, the rings 29A and 29B are movable in the axial direction, so that the same effect of gap adjustment as described above can be obtained. (However, in the case of ring 29B, a thickness adjusting shim or the like is fitted.) Other embodiments are shown in FIGS. 4 and 5.

This embodiment connects the cap 26 to the outer cap 2.
6A and an inner cap 26B, the rotatable wormshaft 4 is fixed in the axial direction by a thrust bearing 33 interposed between the flange portion 31 of the valve housing 11B and the flange portion 32 of the wormshaft 4, and the valve sleeve 8. This is performed by a thrust bearing 34 interposed between the outer cap 26A, and the pushing adjustment of the valve rotor 7 is performed via a thrust bearing 35 interposed between the valve rotor 7 and the inner cap 26B.

The inner cap 26B fitted with a bearing 13 and a seal 27 that slides on the stub shaft 1 is screwed onto the inner periphery of the outer cap 26A via a threaded portion 36, and is movable relative to the outer cap 26A in the axial direction. Installed. Its outer cap 2
6A is the inner peripheral threaded portion 25 of the valve housing 11B.
It is screwed together so that it can move in the axial direction. Further, lock nuts 37 and 38 for tightening are fixed to both caps 26A and 26B, respectively.

The pin 23 that prevents rotation between the wormshaft 4 and the valve sleeve 8 is, as shown in FIG.
It is fitted into an axial longitudinal groove 39 formed at the end of the sleeve 8.

Therefore, by removing both caps 26A and 26B from the stub shaft 1, the valve sleeve 8 and the valve rotor 7 can be pulled out in the axial direction. As a result, it is possible to facilitate assembly and to facilitate adjustment of the clearance between the valve sleeve 8 and the valve rotor 7.

As explained above, according to the present invention, the inner periphery of the opening of the valve housing is formed to have a larger diameter than the outer periphery of the control valve, and the cap is screwed onto the inner periphery of the valve housing. This facilitates disassembly and assembly, and facilitates clearance adjustment.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of a conventional device, Fig. 2 is a longitudinal cross-sectional view of the main part of the present invention, Fig. 3 A and B are enlarged views of the main part, and Fig. 4 is a longitudinal cross-sectional view of the main part of another embodiment. , FIG. 5 is a plan view of the main part thereof. 1... Stub shaft, 4... Wormshaft, 6... Control valve, 7... Valve rotor, 8... Valve sleeve, 11B... Valve housing, 12... Thrust bearing, 2
0, 21, 23...Pin, 22, 31, 32...
Flange, 24, 39...Groove, 25, 36...Threaded portion, 26, 26A, 26B...Cap, 29
...Ring, 33,34,35...Thrust bearing, 37,38...Lock nut.

Claims (1)

[Claims] 1. A stub shaft to which input rotation is transmitted, a worm shaft that is screwed into a piston that is directly connected to the worm shaft via a torsion bar, and a worm shaft that is selectively applied to the left and right cylinder chambers of the piston by switching based on the rotational phase of both shafts. The control valve is composed of a valve rotor and a valve sleeve connected to either the stub shaft or the worm shaft, and the rotating sliding surfaces of the two are centered around the rotation axis. In a power steering device that has a conical surface, the inner periphery of the opening of the valve housing is formed to have a larger diameter than the outer periphery of the control valve,
A power steering device in which a cap that pivotally supports a stub shaft is screwed into the opening of the valve housing.