Shock Absorbing Device

Abstract

To provide an impact absorber which achieves improvement of impact absorption performance.SOLUTION: An impact absorber 1 includes: a cylindrical bumper reinforcement 10 which extends in a vehicle width direction and whose dimension as seen in a vehicle height direction is smaller than a dimension as seen in the vehicle height direction of a side member; reinforcement members 20 each of which reinforces an end as seen in the vehicle width direction of the bumper reinforcement 10; and crash boxes 30 each provided between the side member and the bumper reinforcement 10. The crash box 30 includes: a first impact absorption part 31 disposed in front of the side member and extending forward from a front end of the side member; and a second impact absorption part 32 disposed between the end as seen in the vehicle width direction of the bumper reinforcement 10 and the reinforcement member 20 and the front end of the side member and extending from the front end of the side member to the front side and the outer side as seen in the vehicle width direction.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a shock absorber that deforms upon collision of a vehicle to absorb shock.

Background Art

[0002] There is known a shock absorber (hereinafter referred to as "conventional device") mounted on the front part of a vehicle that deforms upon collision of the vehicle to absorb shock (see, for example, Patent Document 1 below). This conventional device is disposed in front of a pair of left and right side members (skeletal members of the vehicle) extending in the vehicle longitudinal direction. The conventional device includes a bumper reinforcement and a crash box. The bumper reinforcement extends in the vehicle width direction. The crash box extends in the vehicle longitudinal direction, the rear end thereof is connected to the front end of the side member, and the front end thereof is connected to a vehicle width direction intermediate portion located slightly inside (center side) of the vehicle width direction end of the bumper reinforcement. When an object collides with the front end of the vehicle, the crash box deforms, thereby absorbing the shock (collision energy).

[0003] This crash box includes a first shock absorber and a second shock absorber. The first shock absorber extends in the vehicle longitudinal direction in front of the side member. The second shock absorber extends from the side surface portion at the front end of the side member toward the end portion in the vehicle width direction of the bumper reinforcement. The first shock absorber and the second shock absorber are connected to the side member via brackets. When an object collides (minor wrap collision) from the front against the vehicle width direction end portion at the front end of the vehicle (for example, to the left (or right) of the front region of the left (or right) side member), the first shock absorber and the second shock absorber deform, and the shock is absorbed. That is, the shock absorption performance of the above conventional device is higher (the amount of collision energy absorbed is larger) than that of a shock absorber in which the second shock absorber is not provided.

Prior Art Documents

Patent Documents

[0004] Patent Document 1 Japanese Patent Application Laid-Open No. 2000-62551 SUMMARY OF THE INVENTION

[0005] As described above, the second shock absorber of the conventional device extends forward and outward in the vehicle width direction from the side surface at the front end of the side member. That is, the extending direction of the second shock absorber is inclined with respect to the extending direction of the side member. In a minor overlap collision, the load acting on the end of the bumper reinforcement acts on the front end of the side member via the second shock absorber, and the direction of the load is inclined with respect to the extending direction of the side member. The side member is designed such that the strength against the load acting in its extending direction is the greatest. Therefore, when a load acts in a direction inclined with respect to the extending direction of the side member at the front end of the side member, the side member (the connection portion between the side member and the second shock absorber) may be deformed or damaged. In this case, the second shock absorber is not stably supported. Therefore, in a minor overlap collision, in the process of an object entering the vehicle body while destroying the front end of the vehicle, the second shock absorber does not deform as intended, and the second shock absorber does not absorb much shock. Therefore, there is a possibility that the shock absorption performance of the conventional device cannot be improved much.

[0006] The present invention has been made to address the above problems, and an object thereof is to provide a shock absorber having improved shock absorption performance.

[0007] To achieve the above object, the shock absorber of the present invention is provided in front of a side member extending in the vehicle front-rear direction. This shock absorber is a bumper reinforcement in a cylindrical shape extending in the vehicle width direction, the dimension of which in the vehicle height direction is smaller than the dimension of the side member in the vehicle height direction, and A reinforcing member that is attached to the upper or lower surface of the end portion of the bumper reinforcement in the vehicle width direction and reinforces the end portion of the bumper reinforcement in the vehicle width direction; A crush box that is provided between the side member and the bumper reinforcement, supports the bumper reinforcement and the reinforcing member, and deforms to absorb an impact when a rearward load acts on the bumper reinforcement; It is provided with. The crush box is A first impact absorbing portion that is disposed in front of the side member and extends forward from the front end of the side member; A second impact absorbing portion that is disposed between the end portion of the bumper reinforcement in the vehicle width direction and the reinforcing member and the front end of the side member, and extends forward and outward in the vehicle width direction from the front end of the side member; It is provided with. The reinforcing member is a cylindrical member that extends parallel to the extending direction of the end portion of the bumper reinforcement in the vehicle width direction, and is thinner than the bumper reinforcement. For example, the front end face of the reinforcing member is located behind the front end face of the bumper reinforcement.

[0008] For example, when an object collides with a region to the left of a portion located in front of the left side member at the front end of a vehicle to which the shock absorber according to the present invention is applied, the object enters the vehicle interior while deforming the bumper reinforcement, the reinforcing member, and the crash box. In this process, the rear surface of the left end portion in the vehicle width direction of the bumper reinforcement is supported by the second shock absorber. The load acting on the left end portion of the bumper reinforcement is mainly applied (transmitted) to the front end surface of the side member via the second shock absorber. Then, a load (a component of the impact load) acts on the side member in its axial direction. As described above, the side member is designed to have a high strength against the load in its axial direction. Therefore, even when a load is applied to the front end surface of the side member via the second shock absorber, the side member continues to support the second shock absorber with almost no deformation or damage. In this state, the first shock absorber deforms so as to fall slightly to the left, and the second shock absorber deforms so as to be bent backward. That is, the collision energy is converted into the deformation energy of the first shock absorber and the second shock absorber and absorbed. Therefore, according to the present invention, a shock absorber with improved shock absorption performance can be provided. In addition, the reinforcing member can be integrally formed, for example, using an extrusion molding method. Therefore, compared with the case where the reinforcing member is formed from a plurality of parts, the number of parts is small, and component management costs, manufacturing costs, etc. can be reduced. In addition, in the initial stage of a collision, it is possible to prevent the increase rate of the load acting on the vehicle (side member) from becoming excessive.

[0009] In the shock absorber according to one aspect of the present invention, the first shock absorber and the second shock absorber are integrally formed.

[0010] For example, the first shock absorber and the second shock absorber are composed of a cylindrical portion extending in the vehicle height direction.

[0011] For example, the crash box is an extruded molded body, and its extrusion direction corresponds to the vehicle height direction.

[0012] According to this, compared with the case where the first shock absorber and the second shock absorber are separate bodies, the number of parts is small, and the parts management cost, manufacturing cost, etc. can be reduced.

[0013] In the shock absorber according to another aspect of the present invention, a through hole is provided in a portion of the bumper reinforcement that is located closer to the center in the vehicle width direction than the portion to which the first shock absorbing portion is connected.

[0014] According to this, it is possible to prevent the increase rate of the load acting on the vehicle (side member) from becoming excessive in the initial stage of a collision.

Brief Description of the Drawings

[0020]

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Best Mode for Carrying Out the Invention

[0021] (Schematic) An impact absorber 1 according to an embodiment of the present invention will be described. First, with reference to FIG. 1, the configuration of the front part of a vehicle V to which the impact absorber 1 is applied will be briefly described. This vehicle V includes a pair of left and right side members SL and SR. The side members SL and SR are cylindrical members extending in the vehicle front-rear direction. The cross-section perpendicular to its longitudinal direction is rectangular. The front end faces of the side members SL and SR are closed by substantially plate-shaped brackets. The side members SL and SR are arranged at intervals in the vehicle width direction and extend in the vehicle front-rear direction respectively. The side members SL and SR are respectively arranged at positions such that the distances in the vehicle width direction from the left end and the right end in the vehicle width direction of the vehicle V are about 1 / 4 of the vehicle width.

[0022] (Configuration) As shown in FIGS. 2 to 5, the impact absorber 1 includes a bumper reinforcement 10, a reinforcing member 20, and a crush box 30. Note that FIG. 5 shows the left half in the vehicle width direction of the front part of the vehicle V. In the following description, since the right half in the vehicle width direction of the impact absorber 1 is symmetric with the left half in the vehicle width direction, the description thereof will be omitted.

[0023] The bumper reinforcement 10 is a cylindrical member extending in the vehicle width direction in front of the side members SL and SR. The bumper reinforcement 10 is curved so that the outer side in the vehicle width direction is located slightly rearward than the inner side in the vehicle width direction in a plan view. As shown in FIG. 6, a cross section perpendicular to the extending direction of the bumper reinforcement 10 is substantially pentagonal. That is, the bumper reinforcement 10 includes a front wall portion 11, a rear wall portion 12, an upper wall portion 13, a first lower wall portion 14, and a second lower wall portion 15. One side surface of the front wall portion 11 faces forward. The rear wall portion 12 is disposed behind the front wall portion 11 and parallel to the front wall portion 11. One side surface of the rear wall portion 12 faces backward. The dimension of the front wall portion 11 in the vehicle height direction is slightly smaller than the dimension of the rear wall portion 12 in the vehicle height direction. The height position of the upper end of the front wall portion 11 and the height position of the rear wall portion 12 are the same. One side surface of the upper wall portion 13 is directed upward. The front end of the upper wall portion 13 is connected to the upper end of the front wall portion 11, and the rear end of the upper wall portion 13 is connected to the upper end of the rear wall portion 12. One side surface of the first lower wall portion 14 is directed downward. The first lower wall portion 14 is disposed below the upper wall portion 13 and parallel to the upper wall portion 13. The dimension of the first lower wall portion 14 in the vehicle front-rear direction is slightly smaller than the dimension of the upper wall portion 13 in the vehicle front-rear direction. The rear end of the first lower wall portion 14 is connected to the lower end of the rear wall portion 12. The second lower wall portion 15 is directed forward and downward. The second lower wall portion 15 is inclined with respect to the front wall portion 11 and the first lower wall portion 14. One end of the second lower wall portion 15 is connected to the front end of the first lower wall portion 14 , and the other end of the second lower wall portion 15 is connected to the lower end of the front wall portion 11 .

[0024] For example, the wall thicknesses of the front wall portion 11, the rear wall portion 12, the upper wall portion 13, the first lower wall portion 14, and the second lower wall portion 15 are "6 mm", "2.7 mm", "5 mm", "5 mm", and "4 mm", respectively.

[0025] The dimension of the bumper reinforcement 10 in the vehicle height direction is smaller than the dimensions of the side members SL, SR in the vehicle height direction.

[0026] Further, as shown in FIG. 3, a circular through-hole TH is provided in the middle portion of the upper wall portion 13 in the longitudinal direction.

[0027] The reinforcing member 20 is disposed on the upper surface of the end portion of the bumper reinforcement 10 in the longitudinal direction, and reinforces the end portion of the bumper reinforcement 10. The reinforcing member 20 is a cylindrical member substantially parallel to the extending direction of the end portion of the bumper reinforcement 10. The cross-section perpendicular to the longitudinal direction of the reinforcing member 20 has a rectangular shape. As shown in FIG. 5, in plan view, the width W of the reinforcing member 20 20 and the width W of the bumper reinforcement 10 10 are substantially the same. One end of the reinforcing member 20 in the longitudinal direction is located at the left end of the bumper reinforcement 10, and the other end of the reinforcing member 20 is located to the left of the region in front of the side member SL. The reinforcing member 20 is fastened to the upper wall portion 13 of the bumper reinforcement 10 using a set of bolts and nuts.

[0028] As shown in FIG. 2, the crash box 30 includes a first shock-absorbing portion 31 and a second shock-absorbing portion 32, which are integrally formed. Specifically, the crash box 30 is integrally formed using an extrusion process. The extrusion direction corresponds to the vehicle height direction when the crash box 30 is assembled to the vehicle. Therefore, the shape of the cross-section perpendicular to the vehicle height direction of the crash box 30 is the same regardless of the cutting position. The dimension of the crash box 30 in the vehicle height direction is substantially the same as the dimension of the side member SL in the vehicle height direction. That is, the dimension of the crash box 30 in the vehicle height direction is larger than the dimension of the bumper reinforcement 10 in the vehicle height direction. As described above, the reinforcing member 20 is assembled to the upper surface of the end portion of the bumper reinforcement 10, and the dimension of this portion in the vehicle height direction is substantially the same as the dimension of the crash box 30 in the vehicle height direction.

[0029] In plan view, the first impact absorption portion 31 has a substantially rectangular shape extending in the vehicle longitudinal direction. The rear end portion of the first impact absorption portion 31 is fastened to the front end of the side member SL. The front end portion of the first impact absorption portion 31 is connected to the intermediate portion in the vehicle width direction (the portion located in front of the side member SL) of the bumper reinforcement 10. When the crash box 30 is assembled to the vehicle V, the axis of the first impact absorption portion 31 (the center line in the vehicle width direction in the plan view of the first impact absorption portion 31) coincides with the vehicle longitudinal direction.

[0030] More specifically, as shown in FIG. 5, the first impact absorption portion 31 includes an inner wall portion 311, an outer wall portion 312, a rear wall portion 313, and a front wall portion 314. The inner wall portion 311 and the outer wall portion 312 extend in the vehicle longitudinal direction. The outer wall portion 312 is disposed outward in the vehicle width direction (leftward in FIG. 2) as viewed from the inner wall portion 311. The rear end positions of the inner wall portion 311 and the outer wall portion 312 are the same. Since the bumper reinforcement 10 is curved as described above, the front end of the outer wall portion 312 is located slightly rearward of the front end of the inner wall portion 311. The rear wall portion 313 is perpendicular to the front wall portion 314 and the outer wall portion 312. The front wall portion 314 is along the rear surface of the region of the bumper reinforcement 10 that is located in front of the side member SL. The rear ends of the inner wall portion 311 and the outer wall portion 312 are connected to the rear wall portion 313, and the front ends of the inner wall portion 311 and the outer wall portion 312 are connected to the front wall portion 314. A through hole penetrating from the front surface to the rear surface is formed in the rear wall portion 313. Further, a flange portion 315 extending inward in the vehicle width direction (rightward in FIG. 5) along the rear surface of the bumper reinforcement 10 is formed at the front end of the inner wall portion 311. A through hole penetrating from the front surface to the rear surface is formed in the flange portion 315.

[0031] A rib R1 is formed in the space surrounded by the inner wall portion 311, the outer wall portion 312, the rear wall portion 313, and the front wall portion 314. The rib R1 extends outward in the vehicle width direction from the central portion in the longitudinal direction of the inner wall portion 311 and is connected to the outer wall portion 312.

[0032] The second shock absorption part 32 is formed on the outer side in the vehicle width direction (the left side in FIG. 5) of the outer wall part 312 of the first shock absorption part 31. The second shock absorption part 32 has a substantially triangular shape in plan view. The front end part of the second shock absorption part 32 is fastened to the left end part in the vehicle width direction of the bumper reinforcement 10. The second shock absorption part 32 supports the left end part in the vehicle width direction of the bumper reinforcement 10. Note that the front end part of the second shock absorption part 32 is not connected to the reinforcing member 20.

[0033] More specifically, the second shock absorption part 32 includes an outer wall part 321 and a front wall part 314. The outer wall part 321 extends forward and outward in the vehicle width direction (leftward) from the rear end part of the outer wall part 312 of the first shock absorption part 31. The front-rear direction position of the tip (front end) of the outer wall part 321 is behind the front-rear direction position of the front end of the outer wall part 312. The front wall part 322 extends along the rear surface of the left end part of the bumper reinforcement 10 from the front end of the outer wall part 312. The tip of the outer wall part 321 is connected to the left end part of the front wall part 322.

[0034] A rib R2 is formed in the space surrounded by the outer wall part 312, the outer wall part 321, and the front wall part 322. The rib R2 extends forward and outward in the vehicle width direction from the connection part between the outer wall part 312 and the outer wall part 321 and is connected to a substantially central part of the front wall part 322. Further, a flange part 323 that extends outward in the vehicle width direction (leftward in FIG. 5) along the rear surface of the bumper reinforcement 10 is formed at the front end of the outer wall part 321. A through hole that penetrates from the front surface to the rear surface is formed in the flange part 323.

[0035] Bolts are inserted into the through holes formed in the flange portion 315 and the through holes formed in the flange portion 323, and the front end portion of the crash box 30 is fastened to the bumper reinforcement 10 by these bolts. Further, bolts are inserted into the through holes formed in the rear wall portion 313, and the rear end portion of the crash box 30 is fastened to the front end face of the side member SL by these bolts. Note that the lower surface of the bumper reinforcement 10 and the lower surface of the crash box 30 are located in substantially the same plane. Also, the upper surface of the reinforcing member 20 and the upper surface of the crash box 30 are located in substantially the same plane. The left end portion of the bumper reinforcement 10 and the reinforcing member 20 overlap the left half portion of the front surface of the front wall portion 322 of the second impact absorbing portion 32. That is, although a substantially half region on the vehicle width direction end side of the front surface of the front wall portion 322 cannot be visually recognized from the front of the vehicle V, the other regions of the front wall portion 322 are exposed. On the other hand, the bumper reinforcement 10 partially overlaps the lower portion of the front surface of the front wall portion 314 of the first impact absorbing portion 31. That is, the lower portion of the front wall portion 314 cannot be visually recognized from the front of the vehicle V, but the portion above it is exposed.

[0036] (Function and Effect) When an object OB collides with a region on the left side of the front end of the vehicle V, which is located in front of the side member SL, the object OB enters the vehicle interior while deforming the bumper reinforcement 10, the reinforcing member 20, and the crash box 30, as shown in FIGS. 7(A) to 7(D). In this process, the rear surface of the left end portion in the vehicle width direction of the bumper reinforcement 10 is supported by the second shock absorbing portion 32. The load acting on the left end portion of the bumper reinforcement 10 is mainly applied (transmitted) to the front end surface of the side member SL via the outer wall portion 321 and the rib R2 of the second shock absorbing portion 32. Then, a load (a component of the impact load) acts on the side member SL in its axial direction. As described above, the side member SL is designed to have a high strength against the load in its axial direction. Therefore, even when a load is applied to the front end surface of the side member SL via the second shock absorbing portion 32, the side member SL continues to support the second shock absorbing portion 32 with almost no deformation or damage. In this state, the first shock absorbing portion 31 deforms so as to fall slightly to the left, while the second shock absorbing portion 32 deforms so as to be bent backward. That is, the collision energy of the object OB is converted into the deformation energy of the first shock absorbing portion 31 and the second shock absorbing portion 32 and absorbed.

[0037] The load applied to the entire end surface of the side member SL (the load in the axial direction of the side member SL) changes as shown in FIG. 8. That is, the load increases relatively rapidly immediately after the object OB collides. That is, as the entry amount (stroke) of the object OB increases, the load increases relatively rapidly and reaches a peak. Then, as the stroke further increases, the load decreases slightly, but a certain amount of load is maintained. Here, the shock absorption amount corresponds to the integral value of the load in the figure. In the present embodiment, the load increases relatively rapidly at the initial stage of the collision, and then the load is maintained without much decrease. Therefore, according to the present embodiment, the shock can be efficiently absorbed.

[0038] In addition, in this embodiment, a through hole TH is provided in the upper wall portion 13. In addition, the wall thickness of each wall portion of the bumper reinforcement 10 is set to be slightly smaller than the wall thickness of the conventional bumper reinforcement. As a result, when an object collides with the central portion in the vehicle width direction of the vehicle V, it is possible to prevent the peak value of the load applied to the side members SL and SR and the increase rate of the load in the initial stage of the collision from becoming excessive.

[0039] Further, the crush box 30 is integrally formed using an extrusion molding method. Therefore, compared with the case where the first shock absorbing portion 31 and the second shock absorbing portion 32 are manufactured separately and then joined together to form the crush box 30, the component management cost can be reduced. In addition, the number of manufacturing processes can be reduced. Therefore, the manufacturing cost of the shock absorbing device 1 is low.

[0040] Furthermore, in the implementation of the present invention, it is not limited to the above embodiment, and various changes are possible without departing from the object of the present invention.

[0041] For example, instead of the above-described reinforcing member 20, as shown in FIGS. 9 to 12, a reinforcing member 40 may be employed. The reinforcing member 40 is slightly more elongated than the reinforcing member 20. That is, the width W40 of the reinforcing member 40 is smaller than the width W of the bumper reinforcement 10. In a state where the reinforcing member 40 is attached to the upper wall portion 13, the wall surface of the reinforcing member 40 facing forward is located behind the wall surface of the front wall portion 11 of the bumper reinforcement 10. Further, in the example using the reinforcing member 20, one end of the reinforcing member 20 is located in front of the central portion in the vehicle width direction of the front wall portion 322, whereas one end of the reinforcing member 40 is located in front of the right end of the front wall portion 322. Note that one end surface of the reinforcing member 40 is inclined with respect to the longitudinal direction of the reinforcing member 40. 10

[0042] ​If the reinforcing member 40 is adopted, when an object collides with the central portion in the vehicle width direction of the vehicle V, it is possible to more effectively prevent the peak value of the load applied to the side members SL and SR and the increase rate of the load in the initial stage of the collision from becoming excessive.

[0043] Further, when the reinforcing member 40 is adopted, when the object OB collides with the left end portion of the vehicle V, the first shock absorber 31 and the second shock absorber 32 deform as shown in FIG. 12. At this time, the load acting on the side member SL changes as shown by the broken line in FIG. 8. That is, in this case, compared with the case where the reinforcing member 20 is adopted, the increase rate of the load in the initial stage of the collision is small. In addition, the entry stroke of the object OB when the load reaches the peak is larger than that in the case where the reinforcing member 20 is adopted. Thus, when the reinforcing member 40 is adopted, since the change in the load in the initial stage of the collision is gentle, the influence on the occupants of the vehicle V can be reduced.

[0044] Further, in the above embodiment, the example in which the reinforcing member 20 (reinforcing member 40) is attached to the upper surface of the upper wall portion 13 of the bumper reinforcement 10 is shown. However, for example, the reinforcing member 20 (reinforcing member 40) may be attached to the lower surface of the first lower wall portion 14 of the bumper reinforcement 10. That is, when viewed from the front of the vehicle V, the entire (at least about half) of the front wall portion 322 may be covered by the end portion of the bumper reinforcement 10 and the reinforcing member 20.

Explanation of Reference Numerals

[0045] 1... Shock absorber, 10... Bumper reinforcement, 20... Reinforcing member, 30... Crash box, 40... Reinforcing member, OB... Object, SL, SR... Side members, TH... Through hole, V... Vehicle

Claims

【Claim 1】 A shock absorber provided in front of a side member extending in the longitudinal direction of a vehicle, a bumper reinforcement extending in the vehicle width direction and having a dimension in the vehicle height direction smaller than that of the side member in the vehicle height direction, a reinforcing member attached to an upper surface or a lower surface of an end portion of the bumper reinforcement in the vehicle width direction for reinforcing the end portion of the bumper reinforcement in the vehicle width direction, a crash box provided between the side member and the bumper reinforcement for supporting the bumper reinforcement and the reinforcing member and deforming to absorb an impact when a rearward load acts on the bumper reinforcement, comprising: the crash box includes a first shock absorption portion disposed in front of the side member and extending forward from the front end of the side member; a second shock absorption portion disposed between an end portion of the bumper reinforcement in the vehicle width direction and the reinforcing member and the front end of the side member and extending forward and outward in the vehicle width direction from the front end of the side member; comprising: The reinforcing member is a cylindrical member extending parallel to the extending direction of the end portion of the bumper reinforcement in the vehicle width direction and is thinner than the bumper reinforcement, and is a shock absorber.

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