JP2002264822A - Impact absorbing means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an impact absorbing means having a characteristic nearly equal to a practically ideal impact absorbing characteristic in comparison with a current model. SOLUTION: This impact absorbing means 13 is provided with a cylindrical body part 13A, several annular ribs 13B, 13C and 13D formed in the peripheral part of the body part, and several deforming parts 13E formed of cylindrical parts at positions between the annular ribs. When an impact load in the axial direction is applied to the impact absorbing means 13, the deforming parts 13E are bent in order from both ends parts toward a central part in the axial direction to absorb a impact.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shock absorbing means, and more particularly to a shock absorbing means suitable for use, for example, in a steering column of an automobile.

[0002]

2. Description of the Related Art Conventionally, as a shock absorbing means used for a steering column of an automobile, for example, Japanese Utility Model Application Laid-Open No. 2-42868.
The one disclosed in Japanese Patent Application Laid-Open Publication No. H10-260, 1993 is known. In the steering column disclosed in the above publication, an upper portion of a small-diameter pipe is inserted from below into a large-diameter pipe on the upper side, and an impact is applied between an upper outer peripheral portion of the small-diameter pipe and a lower inner peripheral portion of the large-diameter pipe adjacent thereto. Absorbing means are provided. The shock absorbing means of the above publication comprises an outer cylindrical member attached to a lower inner peripheral portion of the large-diameter pipe, and an inner cylindrical member attached to an upper outer peripheral portion of the small-diameter pipe. The plurality of arc-shaped ribs formed on the inner peripheral portion and the plurality of arc-shaped ribs formed on the outer peripheral portion of the inner cylindrical member are engaged at upper and lower positions. When an axial collision load is applied to the steering column due to a traffic accident or the like, the large-diameter pipe and the small-diameter pipe are rapidly moved relative to each other in the axial direction. At that time, the arc-shaped ribs of the two cylindrical members of the shock absorbing means are deformed.
Thus, the configuration is such that the collision load applied to the steering column can be absorbed.

[0003]

The conventional shock absorbing means proposed in the above publication is constituted by inner and outer cylindrical members formed with a plurality of arc-shaped ribs. It is disposed over the lower inner peripheral portion of the pipe and the upper outer peripheral portion of the small diameter pipe. Therefore, there has been a drawback that the structure of the shock absorbing means is complicated, the manufacturing cost is increased, and the work of assembling the steering column to the two cylindrical members is complicated. Also, from the specification, page 13, line 11 to page 15, line 10, it is described that the impact energy can be smoothly absorbed by repeatedly elastically deforming the flange. All the flanges are plastically deformed (including elasticity) at once when the shock energy is absorbed, and the flange that has been deformed cannot exhibit the initial shock absorbing power. I will. Therefore, the actual shock absorption characteristics are such that after the load increases once (two times),
It becomes a form that decreases rapidly. Furthermore, conventionally, the above 42
Japanese Unexamined Patent Publication Nos. Hei 7-277203 and Hei 8-268298 are known as shock absorbing means for a steering column other than Japanese Patent Publication No. 868. In the shock absorbing means disclosed in these two patent publications, when a collision load is applied to the steering column, first, the load acting on the steering column sharply increases, and then the load slightly decreases. It had the characteristic that the load suddenly increased again (see FIG. 3). However, from the original purpose of shock absorption, it is ideal that the load suddenly rises to a predetermined magnitude once immediately after the collision load is applied to the steering column, and thereafter the load remains uniform. (See FIG. 4). Therefore, conventionally, there has been a demand for a shock absorbing means capable of obtaining such ideal load fluctuation characteristics. Accordingly, an object of the present invention is to provide a shock absorbing means which has a simple configuration and can obtain the above-described ideal load fluctuation characteristics.

[0004]

That is, the present invention provides a main body formed in a cylindrical shape, a plurality of annular ribs formed on an outer peripheral portion of the main body at an interval in an axial direction, and a plurality of adjacent ribs. It consists of a cylindrical part of the body part between the annular ribs,
And a plurality of deformed portions that are plastically deformed and shortened when compressed in the axial direction.
According to such a configuration, the configuration of the shock absorbing means can be simplified as compared with the related art, and at the time of assembling at the required position, the main body is fitted to the cylindrical member and then both ends in the axial direction It is only necessary that the part abuts on one member and the other member. Therefore, assembling work of the shock absorbing means becomes easier as compared with the related art. Further, by forming a deformed portion between the adjacent annular ribs, the impact is always absorbed by the new deformed portion, so that the fluctuation characteristics close to the ideal load fluctuation characteristics as described above are obtained. Shock absorbing means can be provided.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiment. In FIG. 1, reference numeral 1 denotes a steering column of the present embodiment, and a steering shaft 2 is inserted through the steering column. The upper end of the steering shaft 2 projects outward from the upper end of the steering column 1, and a handle 3 is attached to the upper end of the steering shaft 2. The steering shaft 2 and the handle 3 are rotatably supported by the steering column 1. A conventionally known airbag 4 is attached to the center of the steering wheel 3, and when the vehicle is suddenly impacted by a traffic accident, the airbag 4 is instantaneously inflated and the driver is instructed. A collision with the steering wheel 3 is prevented. The steering column 1 includes a small-diameter pipe 5 located on the lower side, a large-diameter pipe 6 located on the upper side, and a bracket 7 fitted to the axial center of the large-diameter pipe 6.

[0006] The bracket 7 is replaced with a conventionally known capsule 8.
The steering column 1, the steering shaft 2, and the handle 3 are supported at predetermined positions by being connected to the vehicle body via a detachable member referred to as “separation member”. When an impact load equal to or more than a predetermined value is applied to the handle 3 from the direction of the arrow, the capsule 8 is damaged and the connection between the steering column 1 and the vehicle body is released. next,
An upper outer peripheral portion of the small-diameter pipe 5 is inserted into a lower inner peripheral portion of the large-diameter pipe 6 from below, and a conventionally known cylinder extends over the upper outer peripheral portion of the small-diameter pipe 5 and the lower inner peripheral portion of the large-diameter pipe 6. A shock absorbing member 11 having the shape of a circle is provided. The lower end of the small diameter pipe 5 is in contact with a panel 12 on the vehicle body side. Normally, the large-diameter pipe 6 and the small-diameter pipe 5 are not relatively moved in the axial direction.
When the steering shaft 1 is dropped from the vehicle body due to breakage, the large-diameter pipe 6 is rapidly pushed down toward the panel 12. At that time, the large-diameter pipe 6 is relatively moved with respect to the small-diameter pipe 5, and a part of the impact is absorbed by the impact absorbing member 11. The above configuration is the same as that of the conventionally known steering column 1.

In this embodiment, on the premise of the above-described structure, a substantially cylindrical shock absorbing means 13 is provided in a lower portion of the steering column 1. The shock absorbing means 13 of this embodiment is formed in a substantially cylindrical shape using an elastomer as a material,
Panel 12 and the large-diameter pipe 6
Are arranged without a gap between the lower end of the cover. That is, one end in the axial direction is brought into contact with the panel 12 and the other end in the axial direction is brought into contact with the lower end of the large-diameter pipe 6. The shock absorbing means 13 of the present embodiment includes a cylindrical main body 13.
A, and end annular ribs 13B circumferentially continuous with the outer peripheral portions at both ends in the axial direction of the main body portion 13A.
13C is formed. Each of these end annular ribs 13B,
The outer diameter and thickness of 13C are set to the same size. Further, five intermediate annular ribs 13D are formed at equal intervals in the axial direction on the outer peripheral portion located between the end annular ribs 13B and 13C. Each intermediate annular rib 13
The thickness and outer diameter of D are all the same size, and the outer diameter is set to the same size as the outer diameter of the annular ribs 13B and 13C at both ends. The end annular ribs 13B and 13C and the intermediate annular ribs 13D have a role of making it hard to deform in the radial direction, thereby preventing the shock absorbing means 13 from buckling at once.

Furthermore, the end annular ribs 13B, 1
Each cylindrical portion of the main body 13A between adjacent positions in the 3C and the intermediate annular rib 13D is transformed into a deforming portion 13E.
And When a load compressing in the axial direction acts on each of the deformed portions 13E, each of the deformed portions 13E buckles and deforms so as to be shortened in the axial direction.
By buckling and deforming in this way, the shock can be absorbed. Thus, the shock absorbing means 1 of the present embodiment
3 are six deformation portions 13E between adjacent annular ribs.
Are formed, and they buckle in the axial direction, so that the impact can be absorbed. In this embodiment, the order in which the deformed portions 13E buckle is in contact with the deformed portion 13E or the panel 12 adjacent to the end annular rib 13A that is in contact with the large-diameter pipe 6 on the upper side. One of the deformed portions 13E located adjacent to the end annular rib 13B that has undergone buckling first, and then the deformed portion 13E located adjacent to the opposite end annular rib 13B buckles,
Next, the deformed portions 13E located adjacent to them are sequentially buckled, and the deformed portion 13E located on the axially central side is finally buckled. In this way,
Each deformed part 1 starting from both ends in the axial direction and located in the center in the axial direction
By making the 3E buckle, the load fluctuation characteristics when an impact load in the direction of the arrow is applied to the steering column 1 are made to approach the ideal fluctuation characteristics shown in FIG.

The shock absorbing means 13 constructed as described above
Is pressed into the outer periphery of the small-diameter pipe 5 and
And one end annular rib 13
C is brought into contact with the panel 12, and the other end annular rib 13B is brought into contact with the lower end of the large diameter pipe 6.
When a collision load equal to or more than a predetermined value is applied to the steering column 1, first, the airbag 4 is inflated and the capsule 8 is damaged, so that the steering column 1 is separated from the vehicle body. The large-diameter pipe 6 on the upper side
Is relatively moved downward with respect to the small-diameter pipe 5, and a part of the collision load is first buffered by the shock absorbing member 11 provided over the two pipes 5 and 6. At the same time, the shock absorbing means 13 is axially compressed by the lower end of the large diameter pipe 6 and the panel 12. Then, first, either the uppermost deformed portion 13E adjacent to the upper end annular rib 13B or the lowermost deformed portion 13E adjacent to the end annular rib 13B adjacent to the panel 12 is seated. Buckle and then the opposite end annular rib 13B
Is buckled. Next, the deformed portion 13E adjacent to the two deformed portions E buckles sequentially, and furthermore, the deformed portion 13E on the central side in the axial direction.
E buckles. Since the deformed portions 13E of the shock absorbing means 13 sequentially buckle in this manner, the shock can be absorbed with a substantially constant load. On the other hand, each of the annular ribs 13B, 13C, and 13D does not deform even when compressed in the axial direction, and maintains almost the same shape.

As described above, in the present embodiment, in addition to the conventionally known shock absorbing member 11, the steering column 1
The shock absorbing means 13 is arranged below the lower part. Therefore, it is possible to more effectively absorb the shock as compared with a conventional device that does not include the shock absorbing means 13. More specifically, when a collision load is applied to the steering column 1, an ideal load variation characteristic can be obtained by the shock absorbing means 13. That is, FIG. 5 shows an experimental result of examining a load variation characteristic when a collision load is applied only by the shock absorbing means 13 of the present embodiment. First, the experimental conditions when this experiment was performed will be described. As shown in FIG. 6, a small-diameter pipe 22 as a jig is erected on a horizontally supported base 21. Then, the shock absorbing means 13 of this embodiment is press-fitted. The lower part of the large-diameter pipe 23 as a jig is slidably fitted to the upper end of the small-diameter pipe 22 from above, and the lower end of the large-diameter pipe 23 is connected to the upper end of the shock absorbing member 13. Is in contact with That is, the shock absorbing means 13 is sandwiched between the upper surface of the base 21 and the lower end of the large-diameter pipe 23. In this state, an impact load is applied to the large-diameter pipe 23 from above. The results of this experiment are shown in FIG.
As shown in FIG. First, the load suddenly rises at first, which is due to the buckling of the uppermost deformed portion 13E. Thereafter, the load decreases and then increases. This second load increase is not as great as the first load. The increase in load at this time is accompanied by buckling of the deformed portion 13E at the lowermost end. Thereafter, the load once decreases and then rises again. This increase in load is due to buckling of the second deformed portion 13E from the top. As described above, the shock absorbing means 13 of the present embodiment is configured such that the deformed portions 13E at both ends in the axial direction sequentially buckle,
The load repeatedly decreases and increases, but the range of the increase and decrease of these loads is within a substantially constant range. That is, according to the shock absorbing means 13 of the present embodiment,
A characteristic substantially similar to the ideal load variation characteristic shown in FIG. 4 is obtained. As described above, the shock absorbing means 13 of this embodiment has a simpler structure than that of the conventional one, and can be attached to the steering column 1 only by press-fitting the outer periphery of the small diameter pipe 5. Therefore, it is possible to provide the shock absorbing means 13 which is lower in cost and easier to assemble than the conventional one. further,
As can be understood from the results of the above-described experiments, the shock absorbing means 13 of this embodiment can obtain characteristics substantially similar to ideal load fluctuation characteristics.

As a material of the shock absorbing means 13 of the present embodiment, "Hytrel" (EIDU) is used as an elastomer.
(Registered trademark of PONT DE NEMOURS & COMPANY) # 5557
And # 7247 can be preferably used, but the material is not limited thereto, and any material having similar characteristics may be used, and materials other than elastomer may be used.

Next, FIG. 7 shows a second embodiment of the shock absorbing means 13. In the second embodiment, the end annular rib 13
The thickness of each deformed portion 13E 'adjacent to B and 13C is made thicker by a predetermined dimension than the deformed portion 13E at another position. Other configurations are the same as those of the shock absorbing means 13 in the first embodiment described above. This second
In the shock absorbing means 13 of the embodiment, when the impact load is applied and the shock absorbing means 13 is compressed in the axial direction, the two deformed portions 13E 'located at the both ends first as in the first embodiment. First, buckle, and then the other deformed part 13E
Is buckled. At this time, in the second embodiment, compared to the first embodiment, both deformed portions 13E '
Since the thickness is increased, the inclination of the load decrease after the initial load rise can be reduced. Otherwise, the second embodiment can provide the same operation and effect as the first embodiment. In the second embodiment, both deformed portions 1 on both ends are used.
3E 'is the thickest, and the deformed portion 13E at the adjacent position
From the center to the center in the axial direction.

Next, FIG. 8 shows a third embodiment of the shock absorbing means 13. In the third embodiment, similarly to the second embodiment shown in FIG. 7, the thickness of the deformed portions 13E 'at both ends is set to be thicker than the deformed portions 13E at other positions. . Moreover, in the third embodiment, the axial dimension of the deformed portions 13E 'on both ends is shorter than the axial dimensions of the other deformed portions 13E. At this time, in the third embodiment, as compared with the first embodiment, the increase in the second load can be accelerated, and the amount of decrease in the first load can be reduced. Otherwise, even with the configuration of the third embodiment, the same operation and effect as those of the above-described embodiments can be obtained. In the third embodiment,
The axial dimension of the two deformed portions 13E 'may be set to be the shortest, and the axial size may be set to be longer as the deformed portion 13E is located closer to the center in the axial direction from the adjacent portion.

In each of the above embodiments, the number of the intermediate annular ribs 13D is five and the number of the deformed portions 13E is six. However, the present invention is not limited thereto. Needless to say, an appropriate number may be provided depending on the size and the like. In each of the above embodiments, the case where the shock absorbing means 13 according to the present invention is used as the shock absorbing means of the steering column 1 has been described. However, as in the experimental device shown in FIG. 6, the shock absorbing means 13 is press-fitted to the outer peripheral portion of the small-diameter pipe 22, and both ends in the axial direction are connected to one member (21) and the other member (2).
3), the impact absorbing means of the present invention can be used as an impact absorbing means other than the steering column.

[0015]

As described above, according to the present invention, there is obtained an effect that it is possible to provide a shock absorbing means which has a simpler structure than the conventional one and which can be easily assembled.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 2 is an enlarged sectional view of the shock absorbing means 13 shown in FIG.

FIG. 3 is a view showing a variation characteristic of a load obtained by a conventional shock absorbing means.

FIG. 4 is a view showing an ideal load fluctuation characteristic required for the shock absorbing means.

FIG. 5 is a diagram showing the relationship between the shock absorbing means 13 of the first embodiment shown in FIG. 2 and the load fluctuation characteristics thereof.

FIG. 6 is a cross-sectional view showing an experimental apparatus when the load fluctuation characteristics shown in FIG. 5 are obtained.

FIG. 7 is a sectional view showing a second embodiment of the present invention.

FIG. 8 is a sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Steering column 2 ... Steering shaft 5 ... Small diameter pipe 6 ... Large diameter pipe 13 ... Shock absorbing means 13A ... Body part 13B ... End annular rib 13C ... End annular rib 13D ... Intermediate annular rib 13E ... Deformation part

 ────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kiyotaka Otahara 3-65 Midorigaoka, Toyota-shi, Aichi F-term in Taiho Kogyo Co., Ltd. 3D030 DE25 DE32

Claims (8)

[Claims] 1. A main body formed in a cylindrical shape, a plurality of annular ribs formed on an outer peripheral portion of the main body at an interval in an axial direction, and a cylinder of the main body formed between these adjacent annular ribs. And a plurality of deformed portions that are plastically deformed and shortened when compressed in the axial direction. 2. An end annular rib as the annular rib is formed on an outer peripheral portion at both ends in the axial direction of the main body, and an intermediate annular rib as the annular rib is formed between the end annular ribs. The impact absorbing means according to claim 1, wherein the strength of the end annular rib is set to be higher than the strength of the intermediate annular rib. 3. An axial dimension and a wall thickness of each of said deformed portions are all set to the same size.
3. The shock absorbing means according to claim 2. 4. The impact according to claim 2, wherein the thickness of the deformed portion at a position adjacent to each of the end annular ribs is set to be thicker than the deformed portions at other positions. Absorption means. 5. The deformable portion according to claim 2, wherein an axial dimension at a position adjacent to the end annular rib is set shorter than a deformed portion at another position. Shock absorbing means. 6. The shock absorbing means according to claim 5, wherein said deformed portion is set so that its axial dimension becomes longer as it is located closer to the axial center. 7. The apparatus according to claim 1, wherein the deformable portion is configured such that a portion located on an axial end side of the main body portion and a portion located on an axial center side sequentially undergo plastic deformation. The shock absorbing means according to any one of claims 1 to 6. 8. The shock absorbing means according to claim 1, wherein an elastomer is used as a material.