JPS626353Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rack-and-pinion steering device for an automobile.

FIG. 1 shows an example of a conventional device. In the drawing, a pinion 2 is rotatably supported within a gearbox 1, connected to a handle shaft (not shown), and rotated by rotation of the handle. A rack 3 forming part of the steering link is axially movably supported in the gearbox 1 and meshes with the pinion 2. The resilient plunger 4 is slidably inserted into an inner hole 5 provided in the gear box 1, and is in sliding contact with the back of the rack 3, and the rear of the resilient plunger 4 is connected to a lid 6 fixed to the inner hole 5. The rack 3 is elastically engaged with the pinion 2 by the disc spring 7 provided between them, thereby eliminating the buckling at the meshing part between the rack 3 and the pinion 2, and also connecting the elastic plunger 4 and the lid body. There is a known device that attempts to buffer the collision with 6 and reduce the hitting sound.

In this type of device, it is desirable that the spring load pressing the rack 3 is small from the viewpoint of steering feel, but since the rack 3 forms part of the steering link and is connected to the wheels, Vibration transmitted from the road surface to the wheels when driving on a rough road acts as an impact force on the rack 3, so if the spring load is small, this impact force acts on the rack 3, causing the rack 3 to move away from the pinion 2. , there is a risk that the meshing position will shift, causing wear and damage to the teeth. Therefore, a large spring load is required to resist the return of the resilient plunger 4 as the rack 3 retreats.

However, as shown in FIG.
When a disc spring 7 is provided between the spring 7 and the lid 6, if the spring load is set to a small spring load during normal operation, it will not be possible to obtain a large spring load to resist the return of the resilient plunger 4. The amount of retraction increases, causing problems in the meshing part between the rack 3 and the pinion 2. On the other hand, if a large spring load is set to resist the return of the spring plunger 4, the handle will not move during normal operation. It became heavy,
This will impair the feeling of light steering operation.

That is, in a rack-and-pinion type steering device for an automobile, a small spring load is used to provide light steering operation during normal operation, and a large spring load is used to resist the return of the resilient plunger 4 as the rack 3 retreats due to impact from the road surface. It has been extremely difficult to obtain these at the same time using the disc spring 7.

The present invention was developed in view of these points, and the spring load during normal operation is set small, but the spring load is suddenly increased in response to the return of the rebound plunger during high loads, etc. It is an object of the present invention to provide a rack-and-pinion type steering device capable of resisting return.

The present invention will be explained in detail below based on the embodiment shown in the drawings. Fig. 2 is an enlarged view of the main part of one embodiment of the present invention, and in the drawing, the disc spring receiving surface of the resilient plunger 4 that presses the rack 3. An annular recess 8 is formed in the annular recess 8, and the inner edge of the disc spring 7 is engaged with the annular recess 8. Then, the disc spring 7 and the stepped portion 4 of the annular recess 8
A and A face each other at a distance when the assembly is set, that is, during normal operation. This distance is set so that it decreases as the resilient plunger 4 retreats, and the disc spring 7 comes into contact with the stepped portion 4a during the deformation process. When the device is assembled and set, that is, in normal use, the disc spring 7 is attached to the stepped portion 4a as shown in FIG.
Regardless of the presence of the disk spring, the spring load inherent to the disc spring is applied to the elastic plunger 4. However, when the elastic plunger 4 retreats under high load or due to the transmission of impact force from the road surface, it deforms as shown in Fig. 3. During the process, the disc spring 7 comes into contact with the stepped portion 4a, its inner support position changes from r1 to r3, and the spring constant increases rapidly. Therefore, while the spring load is set high during normal use, a large spring load should be used to resist the return of the resilient plunger 4 when the load is high or when an impact force from the road surface is transmitted. I can do it.

FIG. 4 is a characteristic diagram showing the characteristics of the present invention.
In FIG. 4, point A is when the device is assembled and set, the spring load P1 is set small, and the disc spring 7 is deformed by the return of the resilient plunger 4 under high load. The spring 7 is at the stepped portion 4a
Point B is when the spring comes into contact with the step 4a, and the spring load increases from point A to point B with a spring constant specific to the disc spring. After the disc spring 7 contacts the stepped portion 4a, the inner diameter of the disc spring 7 By changing the support position from r1 to r3, the spring load increases rapidly, and a spring load P3 capable of resisting the return of the resilient plunger 4 at point C at the maximum load can be obtained.

FIG. 5 shows another embodiment of the present invention. In this embodiment, an annular recess 9 is formed in the disc spring receiving surface of the lid 6, and the outer edge of the disc spring 7 is placed in this annular recess 9. engaged. The disc spring 7 and the stepped portion 6a of the annular recess 9 face each other at a distance when assembled and set. During the retraction process of the resilient plunger 4, the disc spring 7 comes into contact with the stepped portion 6a, and its outer diameter support position changes from r2 to r4, making it possible to rapidly obtain a large spring constant.

Since the present invention is as described above, in a rack-and-pinion steering device for an automobile,
During normal operation, the pressure applied to the meshing part between the rack and pinion is small, allowing for light steering operation, and the large spring load is sufficient to withstand the rearward movement of the rack due to the impact force transmitted from the road surface. This can reliably prevent problems in the meshing part. Since the edge of the disc spring is engaged with the annular recess, the disc spring does not shift due to vibrations during running, and a stable action of the disc spring can be obtained at all times.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view showing a conventional example, Figs. 2 and 3 are enlarged views of essential parts showing an embodiment of the present invention, and Fig. 4 is a longitudinal sectional view showing a conventional example.
The figure is a characteristic diagram of the device of the present invention, and FIG. 5 is an enlarged view of the main parts showing another embodiment of the present invention. Explanation of symbols 1...Gearbox, 2...Pinion,
3...Rack, 4...Bullet plunger, 5...Inner hole,
6... Lid body, 7... Belleville spring, 8, 9... Annular recess, 4
a, 6a...stepped portion.

Claims (1)

[Scope of utility model registration request] A pinion 2 is rotatably supported within a gearbox 1 via a bearing, and a rack 3 that meshes with the pinion 2 and forms part of a steering link that is movable in the axial direction within the gearbox 1 is provided.
A cover body 6 is fixed to the inner hole 5 of the gear box 1 by slidably fitting the elastic plunger 4 into the inner hole 5 formed in the gear box 1, and bringing the elastic plunger 4 into sliding contact with the back surface of the rack 3. In a rack-and-pinion steering device for an automobile in which a rack 3 and a pinion 2 are elastically engaged by a disc spring 7 provided between the spring 7 and the back of the elastic plunger 4, either the elastic plunger 4 or the cover body 6 Annular recesses 8 and 9 are formed in one of the disc spring receiving surfaces,
engaging the edge of the disc spring 7 in the annular recesses 8 and 9;
When the assembly is set, the disc spring 7 and the annular recesses 8, 9
A rack-and-pinion steering device for an automobile, characterized in that stepped portions 4a and 6a face each other with a small gap between them.