JP3560490B2 - Energy absorption structure of steering column - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an energy absorbing structure for a steering column, and more particularly to an improvement in a steering column of a type that utilizes bending deformation of a clamp for energy absorption in a secondary collision.
[0002]
[Prior art]
As a type in which the bending deformation of the lower clamp is used for energy absorption at the time of a secondary collision in the steering column, there is a device described in Japanese Utility Model Laid-Open No. 5-29185 and Japanese Utility Model Laid-Open No. 61-29971.
[0003]
Further, as a type utilizing the bending deformation of the upper clamp, there is a device described in Japanese Utility Model Application Laid-Open No. Sho 62-168978 and Japanese Patent Application Laid-Open No. 9-169279.
[0004]
In these energy absorbing structures, the position of the bent portion that bends and deforms by providing a rib or a flange in the deformed portion between the vehicle body mounting portion of the clamp and the jacket tube mounting portion is always constant. This stabilizes the energy absorption load.
[0005]
[Problems to be solved by the invention]
However, in such a steering column utilizing the bending deformation of the lower or upper clamp, a large stroke can be obtained by arranging the jacket tube mounting portion on the steering wheel side with respect to the bent portion of the clamp, and However, there is an inconvenience that the initial load at the time of the secondary collision increases because the load acting in the direction of pushing up the deformed portion increases.
[0006]
Therefore, an object of the present invention is to reduce the initial load of a steering column of a type that absorbs energy during a secondary collision by utilizing bending deformation of a clamp.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a jacket tube for rotatably supporting a steering shaft is supported by a clamp attached to a vehicle body, and energy absorption at the time of a secondary collision is reduced. In a steering column performed by bending deformation of a clamp , the clamp includes a vehicle body attaching portion attached to a vehicle body, and a deformed portion linearly extending obliquely downward to the rear of the vehicle body from the vehicle body attaching portion via a bent portion, A supporting portion formed by bending a lower end side portion of the deformed portion toward the front side of the vehicle body, and a jacket tube mounting portion for rotatably supporting a lower end portion of the jacket tube is provided on the supporting portion; Is characterized in that a fragile portion that can be deformed by an initial load is provided below the bent portion and above the support portion .
[0008]
Further, as described in claim 2, the line connecting the fragile portion and the jacket tube mounting portion, than the line connecting the bending portion and the jacket tube attachment portion, as close to right angles with respect to the axis of the jacket tube The present invention provides an energy absorbing structure for a steering column.
[0009]
As described in claim 3, the weak portion is formed by forming a horizontally long hole in a rib formed in a vertical direction on a deformed portion of a clamp. I will provide a.
[0010]
Therefore, when the fragile portion is deformed before the bent portion is deformed, the load acting in the direction in which the deformed portion is pushed up is reduced, and an increase in the initial load can be suppressed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described with reference to the drawings showing an example in which the present invention is applied to a lower clamp. 1 to 3, reference numeral 1 denotes a jacket tube for rotatably supporting a steering shaft 2, and 3 denotes a distance bracket 4 coupled to the jacket tube 1 slidably in a vertical direction and fixed detachably to a vehicle body 5. The upper and lower upper clamps are integrally connected by a connecting member 3a. Reference numeral 6 denotes a tilt lever for tightening the distance bracket 4 held by the upper clamp 3 with a tightening nut 6a and a tightening bolt 6b. Reference numeral 7 denotes a lower clamp for rotatably supporting the lower end of the jacket tube 1 to the vehicle body 5; Is a spring connecting the distance bracket 4 and the upper bracket 3.
[0012]
The upper clamp 3 has a U-shaped groove 3b opened to the rear side of the vehicle body, and is fixed to the vehicle body 5 by inserting a bolt into a bolt insertion hole 9a formed in a slider 9 that covers the U-shaped groove 3b with upper and lower surfaces. The slider 9 has a substantially U-shaped cross section, and a lower portion of the upper clamp 3 has an extension 9b extending to a rear side of the vehicle body by a predetermined length. The extension portion 9b is inserted into a long hole 3d provided in a front wall portion 3c of the upper clamp 3 which is inclined forward of the vehicle body. When the upper clamp 3 separates from the vehicle body 5, the extension 9b supports the upper clamp 3 so that it does not immediately fall downward.
[0013]
As shown in FIGS. 4 and 5, the lower clamp 7 is formed by bending a sheet metal having a predetermined thickness and a substantially U shape in a plan view into a substantially F shape in a side view, and having a pair of left and right bolt insertion holes 10 formed therein. Deformed portions 13, 13 that bend downward and obliquely hang down with an opening 12 through which the jacket tube 1 penetrates are formed on both left and right end sides of a flat body-shaped mounting portion 11, which is a base portion of a letter shape. Each of the deformable portions 13, 13 is formed of a support portion 14, 14 which is bent substantially at a right angle toward the front of the vehicle body.
[0014]
A substantially elliptical rib 15 is formed in the deformed portion 13 so as to protrude toward the front side of the vehicle body in a vertically long shape, and the rib 15 is provided with a horizontally long slot 16. The long holes 16, 16 are located on the same horizontal line, and are located below the bent portion 17 which becomes the bent portion, and serve as fragile portions which are initially deformed by an initial load. The long holes 16 are for weakening the ribs 15, and the weakening is not limited to the long holes 16, nor is the setting position or number limited. Shafts 21 and 21 (see FIG. 1) projecting from vertical surfaces 20 and 20 formed on both sides of the lower end portion of the jacket tube 1 are fitted into the support portions 14, respectively, and the lower end portion of the jacket tube 1 is rotated. A shaft hole 18 is provided to support the shaft as much as possible.
[0015]
The corner at the lower end of the deformed portion 13 is bent substantially at right angles to the front side of the vehicle body to reinforce the deformed portion 13 as shown by a virtual line illustration a. The stamped and formed sheet metal is bent at substantially right angles from the deformed portion 13, a shaft hole 18 is formed in the base, and a square nut 19 is fixed below the shaft hole 18 so as to face each other. . Bolts are inserted through the pair of opposed nuts 19 to support a column cover (not shown).
[0016]
The operation of the steering column according to the above configuration at the time of a vehicle collision will be described. When a driver's load is applied to the steering shaft 2 via the steering wheel by a secondary collision, the jacket tube 1 moves to the front side of the vehicle body, The upper clamp 3 is disengaged from the vehicle body via the U-shaped grooves 3b, 3b and moves toward the front of the vehicle body, and the upper clamp 9 slides on the extension 9b of the slider 9 without falling immediately. On the other hand, when the jacket tube 1 moves to the front side of the vehicle body, as shown in FIG. 6, the lower clamp 7 bends and deforms to the front side of the vehicle body to absorb the impact load.
[0017]
That is, in FIG. 6, the line y connecting the jacket tube mounting portion A where the shaft hole 18 is located and the weak portion B where the elongated hole 16 is located is smaller than the line z connecting the jacket tube mounting portion A and the bent portion 17. Since it is set so as to be nearly orthogonal to the axis c of the jacket tube 1, when an impact load (arrow A) is input, the fragile portion B is first bent and deformed toward the front of the vehicle body. When the deformation of the fragile portion B proceeds to some extent, the load for bending the bent portion 17 becomes larger than the load for bending the fragile portion B, so that the deformation of the bent portion 17 starts and the fragile portion B The deformation stops. This prevents the deformation portion 13 from being deformed in two stages, thereby preventing the initial load from increasing.
[0018]
As described above, by setting the weakened portion B having a low rigidity in the middle of the deformable portion 13, the load acting in the direction of pushing up the deformable portion 13 against the impact load can be reduced, so that the initial load is reduced. This means that, as shown in FIG. 7, by bringing the position of the fragile portion B closer to the jacket tube 1, the amount of deformation on the fragile portion B side is reduced, and the deformation of the bent portion 17 is increased. Alternatively, the energy absorption characteristic can be tuned by increasing the amount of deformation of the fragile portion B by bringing the position of the fragile portion B closer to the bent portion and reducing the amount of deformation of the bent portion 17.
[0019]
8 and 9 show a lower clamp according to a third embodiment of the present invention. The third embodiment differs from the above-described embodiment in that, instead of providing the long hole 16 as the fragile portion B, a ribless portion is provided. 30 is provided, and the other configuration and the operation and effect thereof are the same as those of the previous example, and thus the duplicated description thereof will be omitted.
[0020]
FIGS. 10 and 11 show a lower clamp according to a fourth embodiment of the present invention. The difference from the foregoing embodiment is that ribs 15 for reinforcing the deformed portion 13 are not provided, and the lower clamp is fragile. Notch 31 is provided on both left and right sides of deforming portion 13 as portion B, whereby the deformation load of deforming portion 13 can be reduced, and deforming portion 13 is deformed in two stages. The initial load can be reduced.
[0021]
In the above embodiment, the lower clamp 7 has been described as an example. However, since the energy absorbing structure by the bending deformation of the bent portion 17 can be applied to the upper clamp 3, the provision of the weak portion B is not required for the lower clamp 7. It is not limited to only.
[0022]
【The invention's effect】
According to the present invention described above, even if the deformed portion of the clamp is inclined obliquely downward on the rear side of the vehicle body and the jacket tube mounting portion is provided on the steering wheel side with respect to the bent portion of the clamp, the fragile portion is deformed. As a result, the initial load can be reduced, so that the energy absorbing function can be improved, and the stroke of the clamp can be increased, and the size of the clamp can be reduced.
[Brief description of the drawings]
FIG. 1 is a side view of a steering column showing an embodiment of the present invention.
FIG. 2 is a plan view of FIG.
FIG. 3 is a sectional view taken along line XX of FIG. 1;
FIG. 4 is a front view of the lower clamp.
FIG. 5 is a plan view of a lower clamp.
FIG. 6 is an explanatory diagram of an operation at the time of a secondary collision of the lower clamp.
FIG. 7 is an explanatory diagram of an operation of a lower clamp shown in another example at the time of a secondary collision.
FIG. 8 is a front view of a main part showing another example of the lower clamp.
FIG. 9 is a side view of the lower clamp of FIG. 8;
FIG. 10 is a front view of a main part showing still another example of the lower clamp.
FIG. 11 is a side view of the lower clamp of FIG. 10;
[Explanation of symbols]
c: axis line of the jacket tube 1 y: line z connecting the jacket tube mounting portion A and the fragile portion B: line connecting the jacket tube mounting portion A and the bent portion 17: jacket tube 2: steering shaft 3: upper clamp 4 ... Distance bracket 5 ... Car body 6 ... Tilt lever 7 ... Lower clamp 9 ... Slider 11 ... Car body mounting part 12 ... Opening part 13 ... Deformation part 14 ... Support part 15 ... Rib 16 ... Elongated hole 17 ... Bending part 18 ... Shaft hole 30 ... Rib-less part 31 ... Notch

Claims (3)

In a steering column, a jacket tube rotatably supporting a steering shaft is supported by a clamp attached to a vehicle body, and energy absorption at the time of a secondary collision is performed by bending deformation of the clamp .
The clamp includes a vehicle body mounting portion that is mounted on the vehicle body, a deformed portion that linearly extends obliquely downward to the rear of the vehicle body via a bent portion from the vehicle body mounting portion, and a lower end side portion of the deformed portion is connected to the front of the vehicle body. A support portion bent to the side, and a jacket tube mounting portion for rotatably supporting the lower end portion of the jacket tube is provided on the support portion, and the deformed portion is below the bent portion, and An energy absorbing structure for a steering column , wherein a fragile portion deformable by an initial load is provided above the support portion . Line connecting the fragile portion and the jacket tube mounting portion, than the line connecting the bending portion and the jacket tube mounting portion, according to claim 1, wherein in the axis is configured to be close to right angles to the jacket tube of the steering column Energy absorption structure. 3. The energy absorbing structure for a steering column according to claim 1, wherein the weak portion is formed by forming a horizontally long hole in a rib formed in a vertical direction in a deformed portion of the clamp.

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