JPH0840287A - Energy absorbing steering device - Google Patents

Abstract

PURPOSE:To provide an energy absorbing steering device which can ensure a sufficient energy absorbing stroke so as to effectively absorb shock energy, which has a simple structure and which can be simply manufactured at a low cost. CONSTITUTION:Long belt like parts 8a, 8b which are extended in the axial direction of a steering column 3 and having an upper end pat A which is alone connected to the body 3a of the steering column 3, are provided between adjacent two of slits 7 formed in the steering column 3, and the free end parts on the lower side of the band-like parts 8a, 8b are folded in an U-like shape. The distal ends of the folded parts (the distal ends of curved parts 9a, 9b) are connected to a lower bracket 6 for attaching the lower part of the steering column 3 to a vehicle body.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steering device for a vehicle, and more particularly to a shock absorbing steering device having a shock absorbing function for absorbing an excessive shock force applied to a steering wheel. It is a thing.

[0002]

2. Description of the Related Art A conventional shock absorbing steering device of this type is disclosed in, for example, Japanese Patent Publication No. 46-35526. This device has a structure in which a steering shaft and a steering column (column tube) are each divided into two members, an upper member and a lower member, and they are fitted so that their axial lengths can be reduced. A structure in which the upper member and the lower member are connected to each other via an energy absorbing plate having a U-shaped bent portion at a position where the upper member of the steering shaft is fitted to the lower member. Is.

According to the conventional device having such a structure, when an excessive impact force is applied to the steering wheel attached to the upper end of the steering shaft, energy is absorbed at the fitting positions of the upper and lower two members of the steering shaft. The plate is bent and deformed, and the bending deformation at this time (plastic deformation)
As a result, the impact energy of the steering shaft is absorbed.

[0004]

However, in the conventional shock absorbing steering system as described above, the so-called double fitting structure is formed by dividing the tubular steering column into upper and lower two members and fitting a part of them. Therefore, there are the following problems. That is, when the steering column has a double-fitting structure, the stroke (relative moving length of the upper and lower two members) for absorbing energy is the same regardless of which energy absorption method is adopted. Assuming that the distance between the upper bracket and the lower bracket for attaching the upper and lower parts of the vehicle to the vehicle body is L and the fitting length of the upper and lower two members of the steering column is α, only (L ÷ 2-α) is secured. The reality is that you cannot do it.

Therefore, when the conventional structure as described above is adopted in the steering device using the relatively short steering shaft, it is impossible to secure a sufficient stroke, so that the effective energy absorption capability is not obtained. There is a risk that you will not be able to demonstrate it.

The present invention has been made in view of such circumstances, and an object thereof is to ensure a sufficient energy absorbing stroke and to effectively absorb impact energy. Moreover, it is an object of the present invention to provide an inexpensive shock absorbing steering device which is simple in structure and manufacturing.

[0007]

In order to achieve the above object, according to the present invention, a steering shaft for transmitting the rotation of a steering wheel to a steering gear is coaxially inserted in a cylindrical steering column. In a steering device that is rotatably supported, a plurality of slits are formed in the steering column, and two slits that are adjacent to each other extend in the axial direction of the steering column and only the upper end portion is formed. A long strip portion connected to the body of the steering column is provided, the free end formed on the lower side of the long strip portion is folded back in a U shape, and the tip of the folded portion is attached to the vehicle body at the lower portion of the steering column. I am trying to connect it to the lower bracket for.

Further, in the present invention, the steering column is formed by forming a plurality of slits in a flat plate member and molding the plate member into a tubular shape.

[0009]

[Operation] If an excessive impact force acts on the steering shaft,
The U-shaped bent portion of the long strip portion of the steering column is sequentially bent and deformed, and the energy required for plastic deformation during the bending deformation absorbs the kinetic energy of the steering shaft generated by the impact force. Therefore,
The long strip portion of the steering column functions as an energy absorbing plate.

If a steering column formed by forming a plurality of slits in a flat plate member and forming it into a tubular shape is used, it is possible to easily manufacture a steering column having slits.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
This will be described in detail with reference to FIG.

1 and 2 show a shock absorbing steering system 1 according to the present invention. In FIG.
Is a steering shaft that transmits the rotation of the steering wheel to the steering gear to steer the front wheels of the vehicle.
Reference numeral 3 denotes a tubular steering column (column tube) that rotatably supports the steering shaft 2.

The above-mentioned steering shaft 2 is composed of an upper member 2a having a steering wheel attached to its upper end and a lower member 2b having its lower end meshed with a steering gear. These upper member 2a and lower member 2b
2 are integrally connected to each other by pinning or the like as shown in FIG. 2, and when an excessive impact force acts, the axial length of the steering shaft 2 increases as the lower member 2b bends and deforms. Is configured to reduce.

On the other hand, the steering column 3 is formed into a cylindrical shape as shown in FIG. 1, and the upper end 4a and the lower end 4b of the steering column 3 are an upper bracket 5 and a lower bracket 6.
Each can be attached to the vehicle body via. Then, two pairs of slits 7 extending from the lower end 4c of the steering column 3 to the vicinity of the upper end 4a are formed.

The steering column 3 used in this example is manufactured as follows. First, a rectangular flat plate member made of steel is prepared, and two pairs (four in total) of slits 7 extending in parallel from one end face of the flat plate member to the intermediate portion are formed. After that,
This flat plate member is rolled into a cylindrical shape and both ends thereof are joined by welding or the like to obtain one steering column 3.

The slits 7 are formed parallel to each other along the axial direction of the steering column 3, and the long strip portions 8a, 8 are provided between each pair of slits 7 adjacent to each other.
b is configured. In addition, these long strip portions 8a, 8
b are provided at positions facing each other, their lower ends are made free ends, and their upper ends A are connected to the main body 3a of the steering column 3.

Further, the free ends of the lower ends of the long strip portions 8a and 8b are folded back outward as shown in FIGS. 1 and 2 to form U-shaped bent portions 9a and 9b. The tips of the bent portions 9a and 9b, that is, the tips of the folded portions, are bent pieces 6 of the lower bracket 6 fixed to the vehicle body.
It is integrally connected to a and 6b by welding or the like.

Further, a bearing 10 (see FIG. 2) is arranged on the upper portion of the steering column 3, and a bush 12 (see FIG. 1) having a rotary bearing hole 11 is fitted into the lower end of the steering column 3 to form a bearing 10. The steering shaft 2 is rotatably supported by the bush 12 coaxially with the steering column 3. Although not shown, a steering wheel is attached to an upper end 2a of the steering shaft 2, and a lower end 2b of the steering shaft 2 is meshed with a steering gear.

The shock absorbing steering system 1 having such a structure has the following functions. That is, when an excessive impact force F is applied to the steering shaft 2 through the steering wheel in the direction indicated by the arrow in FIG. 3A, the steering shaft 2 moves in the axial direction as shown in FIG. 3B. And the long strip portions 8a, 8b of the steering column 3 are reduced as the steering shaft 2 is reduced.
U-shaped bent portions 9a, 9b are sequentially bent and deformed,
In response to this, the steering column 3 is moved downward along the axial direction.

Thus, the energy required for the plastic deformation during the bending deformation absorbs the kinetic energy of the steering shaft generated by the impact force, so that the long strip portions 8a, 8b of the steering column 3 are energized. It will function as an absorption plate. The energy absorption at this time is performed over a stroke substantially corresponding to the distance between the upper bracket 5 and the lower bracket 6.

According to the shock absorbing steering device 1 of this embodiment, the long strip portions 8a, 8b are provided on the steering column 3 itself without forming the steering column 3 in the double fitting structure. By using 8b as the energy absorbing plate, it is possible to make the distance (dimension) between the upper bracket 5 and the lower bracket 6 for mounting the steering column 3 on the vehicle body almost the shock absorbing stroke. Moreover, since it is not necessary to dispose the energy absorbing plate as a separate member, it is possible to reduce the number of parts, simplify the configuration, and lower the cost of the device.

Further, the bush 12 is weakly press-fitted to the lower end of the steering column 3 to rotatably support the steering shaft 2. However, since the slit 7 is formed at the lower end of the steering column 3, these are not formed. Due to the presence of the slit 7, the press-fitting work of the bush 12 can be easily performed.

Further, as in this example, since the steering column 3 formed by forming a plurality of slits in the flat plate member to form a tubular shape is used, the steering column 3 having the slits 7 is used. It can be easily manufactured. Moreover, the steering column 3 having various shapes such as a cylindrical shape, a hexagonal shape, and an elliptical shape can be easily manufactured as required.

The embodiment of the present invention has been described above.
The present invention is not limited to this embodiment, and various modifications and changes can be made based on the technical idea of the present invention. For example, in the above-described embodiment, two pairs of slits 7 are formed in the steering column 3 at positions facing each other and the pair of long strip portions 8a and 8b are provided as energy absorbing plates. Increase the number of formation 3
One or more long strips may be provided to connect the bent portions of these free ends to the lower bracket 6.

[0025]

As described above, according to the present invention, a plurality of slits are formed in the steering column, and between the two adjacent slits, the slits extend along the axial direction of the steering column and only the upper end portion is formed. A lower portion for providing a long strip portion connected to the main body of the steering column, folding back a free end formed in a lower portion in a U shape, and fixing a tip of the folded portion to a lower portion of the steering column to a vehicle body. Since it is configured to be coupled to the bracket, the long strip portion can be provided as a shock absorbing plate, and it is not necessary to provide a shock absorbing member as a separate member, and the shock absorbing structure is simple and inexpensive with a small number of parts. A device can be provided.

Moreover, according to the shock absorbing device of the present invention,
Since the steering column does not have a double structure, it is possible to make the dimension between the lower bracket and the upper bracket for mounting the steering column almost the same as the energy absorption stroke. Therefore, if the shock absorbing steering device of the present invention is applied to a vehicle type that requires the use of a short-sized steering column, it is advantageous because a sufficient shock absorbing capacity can be provided.

Further, according to the present invention, since a plurality of slits are formed in the steering column,
Due to the presence of the slit, the work of press-fitting the rotation support member (bearing member) of the steering shaft into the steering column can be easily performed.

When a plurality of slits are formed in a flat plate member and the steering column is formed by molding the plate member into a tubular shape, the steering column can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a perspective view of a shock absorbing steering device according to the present invention.

FIG. 2 is a sectional view of the above-described shock absorbing steering device.

3A and 3B are views showing the operation of the above-described shock absorbing steering device, wherein FIG. 3A is a sectional view showing a state before an excessive impact force is applied to the steering shaft, and FIG. It is sectional drawing which shows the state after an impact force acts.

[Explanation of symbols]

 1 Shock Absorption Steering Device 2 Steering Shaft 3 Steering Column (Column Tube) 5 Upper Bracket 6 Lower Bracket 7 Slits 8a, 8b Long Strip 9a, 9b Bent 12 Bush (Rotating Bearing Member) A Upper Side of Long Strip edge

Claims (2)

[Claims] 1. A steering apparatus comprising a steering shaft for transmitting rotation of a steering wheel to a steering gear, the steering shaft being rotatably supported while being coaxially inserted and arranged in a cylindrical steering column. 2 with slits adjacent to each other
Between the two slits, a long strip portion extending along the axial direction of the steering column and having only an upper end connected to the main body of the steering column is provided, and a free end formed on the lower side of the long strip portion. A shock absorbing steering device characterized in that the end is folded back in a U shape and the tip of the folded back portion is connected to a lower bracket for mounting the lower portion of the steering column to the vehicle body. 2. The shock absorbing device according to claim 1, wherein the steering column is formed by forming a plurality of slits on a flat plate member and forming the plate member into a tubular shape. Steering device.