JPS6023246Y2 - steering shaft - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a steering shaft constituting an energy-absorbing steering device for an automobile, and more specifically, to a steering shaft having an energy-absorbing portion.

The purpose of this invention is to provide a steering shaft that has energy absorption performance desirable for an energy absorption steering device for an automobile, has a simple structure, is lightweight, and is inexpensive.

Conventionally, in many energy absorbing steering devices for automobiles, the energy absorbing portion of the column jacket undergoes plastic deformation and contracts in the axial direction to absorb energy.

For example, in the one shown in FIG. 1, a column jacket 1 is divided into two parts, an outer jacket 2 and an inner jacket 3 fitted into the outer jacket 2, and a hardness member 5 is placed in a cylindrical space 4 in which both fit.・It is press-fitted and looks intimidating.

However, in the case of this energy absorption structure, the predetermined energy absorption performance is likely to be impaired due to rust or dust generated on the surface of the inner jacket 3 or deformation due to careless bruises.

In addition, in the event of a so-called secondary collision, in which the occupant collides with the steering wheel due to a head-on collision, steering,
Since the ring shaft also needs to be contracted in the axial direction,
The steering shaft is also divided into a plurality of parts and connected so as to be contractible in the axial direction.

For the reason mentioned above, the bracket for attaching the column jacket to the vehicle body is detachably attached to the vehicle body via a slide block.

For this reason, in order for the column jacket to contract in the event of a second collision, it is necessary to contract the steering shaft and separate the bracket from the slide block, which requires extra energy.
There was a performance drawback in that the impact force on the occupants was also increased.

Furthermore, the conventional energy-absorbing steering device as described above has the disadvantage that the structure of the column jacket, steering shaft, and bracket as well as the structure for attaching the bracket to the vehicle body are quite complex, which increases the weight and manufacturing cost. there were.

The object of this invention is to provide a steering shaft that solves the above-mentioned drawbacks of conventional energy-absorbing steering devices.

The gist of this invention is to fit the outer shaft and the inner shaft so that they can move relative to each other only in the axial direction by means of serrations, to form a tapered part on the rear side of the serrations in the inner shaft, and to form a tapered part in this tapered part, the outer shaft A deformable member is provided which deforms in response to the moving force during relative movement between the outer shaft and the inner shaft and presses against the inner cylinder portion of the outer shaft.

This invention will be explained below with reference to illustrated embodiments.

FIG. 2 shows the state in which the energy absorbing steering device using the steering shaft of this invention is attached to an actual vehicle.

In the figure, reference numeral 11 denotes a steering shaft, a steering wheel 12 is attached to one end of the steering shaft, and the other end is connected to a steering gear box (not shown) via a joint 13.

In the figure, 16 is a jacket that rotatably supports the steering shaft 11, and 15 is a bracket that is fixed to the jacket 16 and attaches it to the vehicle body 14.

FIG. 3 shows an embodiment of the steering shaft according to this invention, in which 17 is an outer shaft and 18 is an inner shaft.

Both are fitted so that they can move relative to each other only in the axial direction by fitting the female serrations 19 formed on the inner surface of the outer shaft 17 and the male serrations 20 formed on the outer surface of the inner shaft 18.

21 is the male serration 20 of the inner shaft 18
A tapered part tapered downward formed upward from the rear side, that is, from its upper end (right end in FIG. 3), and a cylindrical part formed by cutting out this tapered part 21 and the female serrations 19. There is a hole 2 in the gap with 17a.
The deformable member 22 is provided by filling 4 with a soft plastic such as an elastomer, rubber, or the like.

In addition, in order to facilitate filling of the deformable member such as soft plastic or rubber, the upper end 2 of the outer shaft 17 is
3 is caulking.

In this way, in the structure shown in FIG. 3, the outer shaft 17 and the inner shaft 18 are separated by male and female serrations 1
9.20, and are connected to prevent inadvertent relative movement during use due to the filling of the deformable member 22.

In a steering shaft with this structure, if an occupant collides with the steering wheel, the inner shaft 1
8 compressively deforms the deformable member 22 and moves relative to it and contracts, and the deformable member 22 receives the force of the tapered part 21 and becomes the cylindrical part 1.
By press-fitting to 7a, the frictional force exerts the effect of absorbing energy.

The energy absorption characteristics can be adjusted arbitrarily by appropriately selecting the inner diameter of the female serrations, the inner diameter of the cylindrical portion 17a, the outer diameter and axial length of the deformable member 22, and the material and hardness of the deformable member 22. Can be adjusted.

As described above, the steering shaft of the present invention can easily obtain desired energy absorption performance depending on the conditions of the energy absorption portion (female serration, deformable member).

In addition, since the deformable member is not metal, it does not rust, is not affected by deformation due to dust, foreign matter, or bruises, and has stable energy absorption performance over a long period of time without being affected by such phenomena. is obtained.

Furthermore, the energy absorbing steering device using the steering shaft of this invention has a simple structure in which the column jacket simply rotatably supports the steering shaft, and is naturally small, lightweight, and inexpensive.

Therefore, there are fewer space constraints and the layout is easy.

Moreover, since the only energy absorbing part is the steering shaft, its energy absorbing performance can be designed freely.
It is possible to construct a highly safe energy absorbing steering device that can sufficiently reduce the impact force on the occupant during a secondary collision.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing the energy absorption part of a conventional column jacket, Fig. 2 is a side view of an energy absorbing steering device using the steering shaft of this invention, and Fig. 3 is an embodiment of the steering shaft of this invention. FIG. 17...Outer shaft, 17a...
・Inner cylinder part, 18...Inner shaft, 19・
...Female serrations, 20...Male serrations, 21...Tapered portion, 22...
Deformed member.

Claims (1)

[Scope of utility model registration request] The outer shaft and the inner shaft are fitted to each other through serrations so that they can move relative to each other only in the axial direction,
A tapered part is formed on the rear side of the serrations in the inner shaft, and this tapered part is deformed by the movement force when the outer shaft and the inner shaft move relative to each other, and is crimped to the inner cylindrical part of the outer shaft. A steering shaft characterized by being provided with a deformable member.