JPS5851096Y2 - 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 an energy absorbing steering device for an automobile with a steering shaft that is simple in structure, lightweight, and inexpensive, and has energy absorbing performance that is heavy on the vehicle.

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.・is press-fitted.

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 a vehicle occupant collides with the steering wheel due to a head-on collision, the steering shaft must also be retracted in the axial direction, so the steering shaft is also divided into multiple parts so that it can be retracted in the axial direction. combined.

The bracket for attaching the column jacket to the vehicle body is removably attached to the vehicle body via a slide block for the above-mentioned reason.

Therefore, in order for the column jacket to contract in the event of a second collision, the steering shaft must be contracted and the housing and bracket must be separated 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 complicated, which increases the weight and manufacturing cost. there were.

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

The gist of this invention is to fit an outer shaft and an inner shaft through serrations so that they can move relative to each other only in the axial direction, provide a holding part for a hard member on the inner shaft, and connect the holding part to the serration valley of the outer shaft. The steering shaft has a structure in which a hard member is press-fitted.

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.

3 to 5 show a first embodiment of the steering shaft according to this invention, in which numeral 17 represents an outer shaft and numeral 18 represents an inner shaft.

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, both can be relatively movable only in the axial direction.

In the figure, reference numeral 21 denotes a hardness member, which is press-fitted between the groove-shaped holding part 22 provided in the circumferential direction of the inner shaft 18 and the valley part of the female serration 19 of the outer shaft 17. (Figure 4) The C hardness member 21 is harder than the female serrations 19 and the inner shaft 18, and serves to maintain the distance between them and to integrally connect them, and the one shown is spherical, but in some cases It may be cylindrical or prismatic.

Figure 3 shows the outer shaft 17 and inner shaft 1.
After fitting 8 with serrations 19.20,
This shows the initial stage of press-fitting the hardness member 21.

That is, the holding portion 22 of the inner shaft 18 and the slit 23 provided at the end of the outer shaft 17 in the same phase as the trough of the female serration 19 (FIG. 4) are aligned in the axial direction, and the slit 23 The hardness member 21 is inserted into the holding part 22 through the holding part 22.

Figure 4 shows three hardness members 21 at positions dividing the circumference into three equal parts.
The number and arrangement of the walls showing the inserted state are not limited to these.

Among them, for example, the inner shaft 18 has female serrations 1.
The hardness member inserted into the holding part is immobilized by providing a hole with a shape that matches the shape of the hardness member to become the holding part in a phase matching with the trough part 9, and burying a considerable portion of the hardness member 21 in the hole. It is also possible to omit the slits 23 if it is possible to maintain this and match the phase with the troughs of the female serrations 19.

After inserting the hard member 21 into the holding portion 22 and aligning it with the trough of the female serrations 19 as described above, the outer shaft 17 and the inner shaft 18 are fitted even deeper to hold the hard member 21. FIG. 5 shows the state in which it is press-fitted between the portion 22 and the valley of the female serration 19.

Thus, the outer shaft 17 and the inner shaft 1
8 is integrally assembled using the hardness member 21 as an intermediary.

FIG. 5 shows that the thin end 24 of the outer shaft 17 is made smaller than the outer diameter of the male serrations 20 as a means to prevent unexpected relative movement in the axial direction of the steering shaft during use. The annular groove 25 provided in the circumferential direction of the inner shaft 18 is aligned with the hole 26 provided in the outer shaft 17, and the plastic 2 is inserted into the annular groove 25 through the hole 26.
A configuration filled with T is shown.

Next, FIG. 6 shows a second embodiment of this invention.
A holding part 22' as a small-diameter stepped part is provided at the tip of the inner shaft 18, and a hard member 21 held by a retainer 28 is press-fitted between the holding part 22' and the valley of the female serration 19.

Naturally, the outer diameter of the retainer 28 is smaller than the inner diameter of the female serrations 19.

When the steering shaft of this invention shown as an embodiment is used in an energy-absorbing steering device as shown in FIG. Move relative to and leave.

At the same time, in the steering shaft 11, the outer shaft 17 and the inner shaft 18 move relative to each other in the axial direction and contract.

At this time, the troughs of the female serrations 19 are connected to the hardness member 21.
This produces an energy absorption effect that reduces the impact force on the occupant by an amount equivalent to the energy required for the plastic deformation in the range where the plastic deformation occurs.

As mentioned above, since the energy absorbing portion of the steering shaft of this invention (the valley of the female serration 19, the hardness member 21) is located inside the steering shaft,
There is no occurrence of rust, adhesion of dust, adhesion of foreign matter, or deformation due to bruises, and the predetermined energy absorption performance is exhibited in a stable manner without being affected by such phenomena.

Further, there is an advantage that desired energy absorption performance can be easily obtained by appropriately designing the number and shape of the hardness members 210.

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

Therefore, there are few space constraints and layout is easy.

Moreover, there is no need to shrink the column jacket, and the only energy absorbing part is the steering shaft.
By obtaining appropriate energy absorption performance, it is possible to sufficiently alleviate the impact force on the occupants in the event of a secondary collision, which has the advantage of high safety.

[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 absorption steering device using the steering shaft of this invention, and Fig. 3 is an energy absorption board of the steering shaft of this invention. 4 is a cross-sectional view showing the process of assembly, taken from IV-IV in FIG.
A cross-sectional view, FIG. 5 is a cross-sectional view showing the assembled state of the former;
FIG. 6 is a sectional view showing another embodiment of the energy absorbing portion of the steering shaft of this invention. 17...Outer shaft, 18...
Inner shaft, 19...Female serrations,
20...Male serrations, 21...Hardness member, 22...Hand holding portion.

Claims (1)

[Scope of utility model registration request] The outer shaft and the inner shaft are fitted together through serrations so that they can move relative to each other only in the axial direction, and
A holding part for holding the hardness member is provided on the inner shaft,
A steering shaft in which a hard member is press-fitted between the holding portion and the female serration valley portion of the outer shaft.