JPH09267754A - Intermediate shaft of steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce costs and to surely absorb shocks by eliminating waste from manufacturing processes and assembling process of the intermediate shaft of a steering device. SOLUTION: The intermediate shaft of a steering device contracted to absorb shocks when receiving shock loads is composed of an intermediate shaft 8 and an inserting shaft 9 fitted in a serration, a non-serration part 8b is provided within a specified angle range of the inner periphery of the intermediate shaft 8 in the serration fitting region, a rod body 20 is fitted in at least one serration groove of the male serration 9a of the outer periphery of the inserting shaft 9 while its position is regulated in an axial direction, and this rod body 20 is inserted into the non-serration part 8b of the inner periphery of the intermediate shaft 8. Upon receiving shocks, the intermediate shaft 8 and the inserting shaft 9 are contracted, but the shocks are absorbed by the resistance of the rod body 20 moved integrally with the inserting shaft 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intermediate shaft of a steering device which absorbs a shock by axially shortening when a shock load more than required is applied. The intermediate shaft is provided between the steering shaft and the steering gear in the automobile steering device.

[0002]

2. Description of the Related Art FIG. 6 shows the structure of a general steering apparatus for an automobile. In the figure, 1 is a steering wheel, 2 is a steering column, 3 is a steering shaft, 4 is a steering gear, 5 and 6 are universal joints, and 7 is an intermediate shaft.

The intermediate shaft 7 transmits the rotational operation force applied to the steering wheel 1 to the steering gear 4 side, but when an excessive impact is applied at the time of a collision, the impact is not transmitted to the driver side. It has a structure that shortens and absorbs impact.

FIG. 7 is a side view of the fracture of the main part of the intermediate shaft. The intermediate shaft 7 includes a hollow shaft 8 and an insertion shaft 9 which are connected to each other so as to be axially displaceable. A female serration 8 a is provided on the inner periphery of the hollow shaft 8, and a male serration 9 a that fits into the female serration 8 a of the hollow shaft 8 is provided on the outer periphery on the distal end side of the insertion shaft 9. A circumferential groove 10 is formed in the outer periphery of the insertion shaft 9 in the middle of the area where the male serration 9a is formed. On the other hand, at two places facing each other by 180 degrees in a region corresponding to the circumferential groove 10 in the hollow shaft 8,
A hole 11 penetrating in the radial direction is provided. The gap between the circumferential groove 10 and the hollow shaft 8 is filled with the resin 12 through the hole 11, and the solidified resin 12 causes the hollow shaft 8 and the insertion shaft 9 to be integrally connected. I have.

[0005] In the intermediate shaft 7 having such a structure, when an excessive impact is applied, the filling resin 12 is sheared,
The insertion shaft 9 enters the hollow shaft 8 and the entire intermediate shaft 7 is shortened, thereby absorbing a shock.

[0006]

However, it is pointed out that, in the above-mentioned prior art, the work efficiency is poor and the production cost is high, such as the need for injecting and curing the filling resin 12 during the assembling, which is troublesome. Is done.

Further, since the place of use is in the engine room where the temperature is likely to be high, it is necessary to take measures to prevent the strength of the filling resin 12 from decreasing.
It is considered that the required shear resistance may not be obtained, and this may lead to a variation in pull-out load.
The detachment load is an impact load when the intermediate shaft 7 is shortened. Further, when the filling resin 12 is sheared, the shedding load is apt to decrease sharply, and it is necessary to consider sufficient shock absorption.

Therefore, it is an object of the present invention to eliminate the waste in the manufacturing process and the assembling process in the intermediate shaft of the steering device and to reduce the cost. Another object of the present invention is to make it possible to control the escape load constantly regardless of the ambient temperature. Still another object of the present invention is to make it possible to absorb the shock sufficiently and surely for a while without the drop load sharply decreasing.

[0009]

The present invention is configured as follows in an intermediate shaft of a steering device that is shortened in the axial direction and absorbs a shock when a shock load more than required is received.

A first intermediate shaft of the present invention comprises a hollow shaft and an insertion shaft serrated and fitted therein, and a serration-free portion is provided in the serration-fitted region within a required angle range of the inner circumference of the hollow shaft. The rod body is inserted in at least one serration groove of the male serration on the outer periphery of the insertion shaft in a state in which the axial position of the rod body is regulated, and the rod body is digging into the non-serration portion of the inner periphery of the hollow shaft.

The second intermediate shaft of the present invention comprises a hollow shaft and an insertion shaft to be inserted therein, and the hollow shaft is provided with female serrations on its inner circumference and the circumference of this female serration. A band-shaped unprocessed part along the axial direction is provided in the above required angular range, and the insertion shaft has male serrations on its outer periphery and is located at two axially separated positions in at least one serration groove. The unprocessed part is provided, and the rod body is interposed between the region between the two unprocessed parts of the serration groove of the insertion shaft and the unprocessed part of the inner circumference of the hollow shaft. The rod body is cut into the unprocessed portion of the inner circumference of the hollow shaft.

In the above invention, a rod is interposed between the hollow shaft and the insertion shaft in the serration fitting region between the two shafts, and the rod is cut into the non-serrated portion or the unprocessed portion of the inner circumference of the hollow shaft. Thus, the hollow shaft and the insertion shaft are constrained so as not to move in the axial direction. However, when the intermediate shaft receives an impact in the axial direction, the insertion shaft and the hollow shaft move relatively to shorten and absorb the impact. The shock absorption is performed by the rod body that moves integrally with the insertion shaft plastically deforms the surface of the non-serration portion of the inner circumference of the hollow shaft along the axial direction.

According to the structure of the present invention as described above, unlike the conventional example, a troublesome process in the assembling process is unnecessary, and the withdrawal load does not change under the influence of the ambient temperature. Moreover, by varying the axial length dimension and the diameter dimension of the rod body, the pull-out load can be set arbitrarily.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The details of the present invention will be described based on the embodiments shown in FIGS.

1 to 5 relate to an embodiment of the present invention. FIG. 1 is a side view of the main shaft of the intermediate shaft, and FIG.
5 is an enlarged view of a main part of FIG. 3, FIG. 3 is a sectional view taken along the line (3)-(3) of FIG. 2, and FIG. 4 is a sectional view taken along the line (4)-(4) of FIG. FIG. 7 is an exploded perspective view of the intermediate shaft.

In the figure, 5 and 6 are universal joints, and 7 is an intermediate shaft. The intermediate shaft 7 includes a hollow shaft 8 and an insertion shaft 9 that are fitted in a state that can be shortened in the axial direction. The hollow shaft 8 and the insertion shaft 9 are made of a metal material.

The hollow shaft 8 has a female serration 8 on its inner circumference.
Although the female serration 8a is provided, the female serration 8a is not provided on the entire circumference, and a band-shaped unprocessed portion 8b is provided along the axial direction in the required angular range θ1 on the circumference. The unprocessed portion 8b where the female serration 8a is not formed is substantially flush with the inner circumference of the hollow shaft 8. Such female serration 8a
Is formed by a drawing process.

The insertion shaft 9 is formed with male serrations 9a fitted on the female serrations 8a of the hollow shaft 8 on the outer periphery thereof, of which three unprocessed portions are located at two axially separated serration grooves. 9b is provided. The unprocessed portion 9b where the male serration 9a is not formed is
It is substantially flush with the outer circumference of the insertion shaft 9. Such male serrations 9a are formed by rolling.

The hollow shaft 8 and the insertion shaft 9 are fitted with serrations, and one roller 20 is interposed between the shafts 8 and 9 in the serration fitting region. The roller 20 corresponds to the rod body in the claims and is made of a metal material such as bearing steel.

More specifically, the roller 20 is inserted into one serration groove in the area between the two unmachined portions 9b of the male serration 9a of the insertion shaft 9 and its position is regulated in the axial direction. A portion of the roller 20 that protrudes from the top of the serration tooth by a required amount is cut into the unprocessed portion 8b of the hollow shaft 8. Since the hollow shaft 8 slightly expands outward in the radial direction due to the presence of the rollers 20, the female serrations 8 a of the hollow shaft 8 and the male serrations 9 of the insertion shaft 9 are in a required angle range including the arrangement position of the rollers 20.
Although it is slightly separated from a, the hollow shaft 8 is in the required angle range including a portion facing the position of the roller 20 by 180 degrees.
The female serration 8a of is the male serration 9a of the insertion shaft 9.
It is designed to be pressed against. Thus, the hollow shaft 8 and the insertion shaft 9 are restrained so as not to relatively move in the axial direction, and the circumferential play between the hollow shaft 8 and the insertion shaft 9 is eliminated.

Next, a method of assembling the intermediate shaft 7 will be described.

That is, in the male serration 9a of the insertion shaft 9, with the roller 20 inserted in one serration groove in the region sandwiched by the unprocessed portions 9b, the insertion shaft 9 is fitted into the hollow shaft 8 in a required fitting dimension. It suffices to insert it to the position that satisfies. This insertion must be a press fit because of the following. First, in the initial stage, the tops of the serration teeth of the male serration 9a of the insertion shaft 9 slightly bite into the unprocessed portion 8b of the inner periphery of the hollow shaft 8 while the male serrations 9a in other regions are moved to the hollow shaft 8 by the male serration 9a. The female serration 8a is fitted with the serration. After that, when the roller 20 axially positioned and held on the outer circumference of the insertion shaft 9 enters the inner circumference of the hollow shaft 8, a portion of the roller 20 protruding from the tooth tip of the male serration 9a by a required amount is formed. , The hollow shaft 8 is bitten into the unprocessed portion 8b on the inner periphery of the hollow shaft 8, and the hollow shaft 8 slightly expands outward in the radial direction. Therefore, in the required angle range including the arrangement position of the rollers 20. The female serration 8a of the hollow shaft 8 is the male serration 9 of the insertion shaft 9.
On the other hand, the female serration 8a of the hollow shaft 8 is brought into pressure contact with the male serration 9a of the insertion shaft 9 within a required angle range including a portion facing the arrangement position of the roller 20 by 180 degrees. It will be.

In the above structure, when a shock load is applied, the resin portion is not sheared and absorbs the shock as in the conventional case, and then the intermediate shaft 7 is not shortened rapidly without resistance. In the shortening operation, the impact is continued to be absorbed until the roller 20 holding portion of the insertion shaft 9 passes through the region where the female serration 8a of the hollow shaft 8 is formed. It is designed to be shortened. Thereby, sufficient shock absorption can be achieved. The impact absorption is performed by the rollers 20 that move integrally with the insertion shaft 9 plastically deform the surface of the non-serration portion 8b on the inner circumference of the hollow shaft 8 along the axial direction. Moreover, unlike the conventional shock absorbing structure utilizing the shearing of the resin, there is no deterioration due to the use atmosphere temperature, and the removal load is kept constant, so that the reliability is high.

By the way, in the case of the intermediate shaft 7 having the above structure, the pull-out load can be arbitrarily changed by appropriately setting the axial length dimension and the diameter dimension of the roller 20. This detachment load is usually set as required.

In the case of the intermediate shaft 7 as described above, it is not necessary to provide the hollow shaft 8 constituting the intermediate shaft 7 with a hole for catching the resin as in the conventional example, so that the number of manufacturing steps can be reduced, and Since it is not necessary to provide the insertion shaft 9 with a circumferential groove as in the conventional example, the number of manufacturing steps can be reduced. Moreover, the assembling work is as simple as inserting the insertion shaft 9 into the hollow shaft 8 by force, which eliminates the conventional troublesome injection and curing of the resin. As a result, the manufacturing cost can be significantly reduced as compared with the conventional example.

It should be noted that the present invention is not limited to only the above embodiment, and various applications and modifications are conceivable. For example, the hollow shaft 8 and the insertion shaft 9 may be spline-fitted instead of serrated. Also, 2
Zeros can be arranged at several places close to each other on the circumference instead of one place on the circumference. In that case, the hollow shaft 8 and the insertion shaft 9
In addition, it is necessary to increase the unprocessed portions 8b and 9b or set the unprocessed portion to be large in the circumferential direction. Further, instead of the cylindrical roller 20, a polygonal rod body such as a triangle or a quadrangle may be used.

[0027]

According to the present invention, since there is no deterioration due to the influence of the ambient temperature and the pull-out load can be maintained constant, high reliability can be obtained. Also, by varying the axial length dimension and diameter dimension of the rod, the pull-out load can be set arbitrarily, so that it is possible to easily and accurately respond to a wide range of shock loads required. . Moreover,
At the time of assembly, it does not require a labor-intensive work as in the conventional case, which contributes to cost reduction and can be realized at a relatively low cost. Furthermore, the pull-out load can be maintained, and the shock can be absorbed sufficiently and reliably.

[Brief description of drawings]

FIG. 1 is a side view of a main part fracture of an intermediate shaft according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG. 1;

3 is an arrow view of a cross section taken along line (3)-(3) of FIG.

FIG. 4 is a sectional view taken along line (4)-(4) of FIG.

5 is an exploded perspective view of the intermediate shaft of FIG.

FIG. 6 is a side view showing the configuration of a general steering device.

FIG. 7 is a side view of a conventional intermediate shaft main part fractured.

[Explanation of symbols]

 7 Intermediate shaft 8 Hollow shaft 8a Hollow shaft female serration 8b Hollow shaft unmachined part 9 Insertion shaft 9a Insertion shaft male serration 9b Insertion shaft unmachined part 20 Roller

Claims (2)

[Claims] 1. An intermediate shaft of a steering device, which is shock-absorbed by being shortened in an axial direction when receiving a shock load more than a required amount, comprising a hollow shaft and an insertion shaft serrated with the hollow shaft, and In the serration fitting region, a non-serration portion is provided in a required angle range of the inner circumference of the hollow shaft, and the rod body is inserted in at least one serration groove of the male serration on the outer circumference of the insertion shaft in a state in which the axial position is regulated, An intermediate shaft of a steering device, wherein the rod body is digged into a portion of the hollow shaft which is not serrated on the inner circumference. 2. An intermediate shaft of a steering device, which is shortened in the axial direction and absorbs a shock when a shock load of a required amount or more is received, the shaft including a hollow shaft and an insertion shaft inserted therein. Has a female serration on its inner circumference and a band-shaped unprocessed portion along the axial direction within the required angular range on the circumference of this female serration.The insertion shaft has a male serration on its outer circumference. And the at least one serration groove is provided with two unmachined portions axially separated from each other, and the region between the two unmachined portions of the serration groove of the insertion shaft and the hollow shaft An intermediate shaft of a steering device, characterized in that a rod body is interposed between the inner peripheral portion and a non-machined portion, and the rod body bites into the inner peripheral portion of the hollow shaft which is not machined.