JP7700003B2 - Shock Absorbing Device - Google Patents

Description

The present invention relates to an impact absorbing device that deforms to absorb impact during a vehicle collision.

There is known an impact absorbing device (hereinafter referred to as a "conventional device") that is mounted on the front of a vehicle and that deforms to absorb impact when the vehicle collides (see, for example, Patent Document 1 below). This conventional device is disposed in front of a pair of left and right side members (vehicle frame members) that extend in the longitudinal direction of the vehicle. The conventional device includes a bumper reinforcement and a crash box. The bumper reinforcement extends in the width direction of the vehicle. The crash box extends in the longitudinal direction of the vehicle, with its rear end connected to the front end of the side member, and its front end connected to a middle part in the width direction of the vehicle that is located slightly inside (towards the center) of the end of the bumper reinforcement in the width direction. When an object collides with the front end of the vehicle, the crash box deforms to absorb the impact (collision energy).

This crash box includes a first impact absorbing portion and a second impact absorbing portion. The first impact absorbing portion is provided in front of the side member and extends in the longitudinal direction of the vehicle. The second impact absorbing portion is provided in front of the side member and extends from the side portion at the front end of the side member toward the end of the bumper reinforcement in the vehicle width direction. The first impact absorbing portion and the second impact absorbing portion are connected to the side member via a bracket. When an object collides from the front (micro-lap collision) with the end in the vehicle width direction 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 impact absorbing portion and the second impact absorbing portion deform to absorb the impact. In other words, the impact absorbing performance of the above conventional device is higher (the amount of collision energy absorbed is larger) than that of an impact absorbing device that does not have a second impact absorbing portion.

JP 2000-62551 A

As described above, the second impact absorbing portion of the conventional device extends from the side portion at the front end of the side member toward the front and outward in the vehicle width direction. That is, the extension direction of the second impact absorbing portion is inclined with respect to the extension direction of the side member. In a micro-lap collision, the load acting on the end of the bumper reinforcement acts on the front end of the side member through the second impact absorbing portion, but the direction of the load is inclined with respect to the extension direction of the side member. The side member is designed to have the greatest strength against the load acting in its extension direction. Therefore, when a load acts on the front end of the side member in a direction inclined with respect to the extension direction of the side member, there is a risk that the side member (the connection portion between the side member and the second impact absorbing portion) will be deformed or damaged. In this case, the second impact absorbing portion will not be stably supported. Therefore, in a micro-lap collision, in the process of an object entering the vehicle body while destroying the front end of the vehicle, the second impact absorbing portion does not deform as intended, and the second impact absorbing portion does not absorb much impact. Therefore, there is a risk that the shock absorbing performance of conventional devices will not be significantly improved.

The present invention was made to address the above problems, and its purpose is to provide a shock absorbing device with improved shock absorbing performance.

In order to achieve the above object, the impact absorbing device of the present invention is provided in front of a side member extending in the front-rear direction of the vehicle.
This shock absorbing device is
A cylindrical bumper reinforcement extending in a vehicle width direction, the dimension of which in a vehicle height direction is smaller than the dimension of the side member in the vehicle height direction;
A reinforcing member attached to an upper side or a lower side of an end portion of the bumper reinforcement in a vehicle width direction and 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, supporting the bumper reinforcement and the reinforcing member, and deforming to absorb an impact when a rearward load acts on the bumper reinforcement;
Equipped with.
The crash box is
a first impact absorbing portion disposed in front of the side member and extending forward from a front end of the side member;
a second impact absorbing portion disposed between an end portion of the bumper reinforcement in the vehicle width direction, the reinforcing member, and a front end of the side member, and extending forward and outward from the front end of the side member in the vehicle width direction;
Equipped with.
The reinforcing member is a tubular member extending parallel to an extension direction of an end portion of the bumper reinforcement in a vehicle width direction, and is thinner than the bumper reinforcement. For example, a front end surface of the reinforcing member is located rearward of a front end surface of the bumper reinforcement.

For example, when an object collides with the front end of a vehicle to which the impact absorbing device according to the present invention is applied, in an area to the left of the portion located in front of the left side member, the object advances into the vehicle interior while deforming the bumper reinforcement, the reinforcing member, and the crash box. In the process, the rear surface of the left end of the bumper reinforcement in the vehicle width direction is supported by the second impact absorbing portion. The load acting on the left end of the bumper reinforcement is mainly applied (transmitted) to the front end surface of the side member via the second impact absorbing portion. Then, a load (a component force of the impact load) acts on the side member in its axial direction. As described above, the side member is designed to have high strength against the load in its axial direction. Therefore, even if a load is applied to the front end surface of the side member via the second impact absorbing portion, the side member continues to support the second impact absorbing portion without being substantially deformed or broken. In this state, the first impact absorbing portion deforms so as to slightly fall to the left, while the second impact absorbing portion deforms so as to be pushed backward. That is, the collision energy is converted into deformation energy of the first impact absorbing portion and the second impact absorbing portion and is absorbed. Therefore, according to the present invention, it is possible to provide an impact absorbing device with improved impact absorbing performance.
Furthermore, the reinforcing member can be integrally formed by, for example, extrusion molding, which reduces the number of parts compared to when the reinforcing member is formed from a plurality of parts, thereby reducing the parts management costs and manufacturing costs.
Furthermore, in the initial stage of a collision, the rate at which the load acting on the vehicle (side member) increases can be prevented from becoming excessive.

In one aspect of the shock absorbing device of the present invention, the first shock absorbing section and the second shock absorbing section are integrally formed.

For example, the first impact absorbing section and the second impact absorbing section are each composed of a cylindrical section extending in the vehicle height direction.

For example, the crash box is an extrusion molded body, and the extrusion direction corresponds to the vehicle height direction.

This reduces the number of parts and reduces parts management costs, manufacturing costs, etc., compared to when the first and second shock absorbing sections are separate.

In another aspect of the impact absorbing device of the present invention, a through hole is provided in the bumper reinforcement in a portion that is located toward the center in the vehicle width direction from the portion to which the first impact absorbing portion is connected.

This prevents the load acting on the vehicle (side member) from increasing too quickly during the initial impact of a collision.

1 is a plan view showing an outline of a vehicle to which an impact absorbing device according to an embodiment of the present invention is applied. FIG. 2 is a perspective view of the impact absorbing device of FIG. 1 . FIG. 2 is a plan view of the impact absorbing device of FIG. 1 . FIG. 2 is a rear view (view from the rear of the vehicle) of the impact absorbing device of FIG. 1 . 2 is an enlarged plan view of the left end portion of the impact absorbing device of FIG. 1 . FIG. 2 is a cross-sectional view of the bumper reinforcement. 4A to 4C are plan views showing the process in which the impact absorbing device of FIG. 1 is deformed in a micro-lap collision. 4 is a graph showing a change in load acting on a front end of a side member in a micro-lap collision. FIG. 11 is a perspective view of an impact absorbing device according to a modified example of the present invention. FIG. 10 is a plan view of the impact absorbing device of FIG. 9 . FIG. 10 is a rear view of the impact absorbing device of FIG. 9 . 10 is an enlarged plan view of the left end portion of the impact absorbing device of FIG. 9 . FIG. 10A to 10C are plan views showing the process in which the impact absorbing device of FIG. 9 is deformed in a minute overlap collision.

(Summary)
An impact absorbing device 1 according to an embodiment of the present invention will be described. First, referring to FIG. 1, a brief description will be given of the configuration of the front part of a vehicle V to which the impact absorbing device 1 is applied. The 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 longitudinal direction. A cross section perpendicular to the longitudinal direction thereof is rectangular. The front end faces of the side members SL and SR are closed by a substantially plate-shaped bracket. The side members SL and SR are disposed at intervals in the vehicle width direction and extend in the vehicle longitudinal direction, respectively. The side members SL and SR are disposed at positions such that the distance in the vehicle width direction from the left end and the right end in the vehicle width direction of the vehicle V is approximately ¼ of the vehicle width.

(composition)
2 to 5, the impact absorbing device 1 includes a bumper reinforcement 10, a reinforcing member 20, and a crash box 30. Fig. 5 shows the left half in the vehicle width direction at the front of the vehicle V. In the following description, the right half in the vehicle width direction of the impact absorbing device 1 is symmetrical to the left half in the vehicle width direction, so a description thereof will be omitted.

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, the cross section perpendicular to the extension direction of the bumper reinforcement 10 is approximately 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.

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.

The vehicle height dimension of the bumper reinforcement 10 is smaller than the vehicle height dimension of the side members SL and SR.

Also, as shown in FIG. 3, a circular through hole TH is provided in the middle of the upper wall portion 13 in the longitudinal direction.

The reinforcing member 20 is disposed on the upper surface of the end of the bumper reinforcement 10 in the longitudinal direction, and reinforces the end of the bumper reinforcement 10. The reinforcing member 20 is a tubular member that is substantially parallel to the extending direction of the end of the bumper reinforcement 10. The cross section perpendicular to the longitudinal direction of the reinforcing member 20 is rectangular. As shown in FIG. 5, in a plan view, the width _W20 of the reinforcing member 20 and the width _W10 of the bumper reinforcement 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 front region 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.

2, the crash box 30 includes a first shock absorbing portion 31 and a second shock absorbing portion 32. These 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 approximately the same as the dimension of the side member SL in the vehicle height direction. In other words, 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 of the bumper reinforcement 10, and the dimension of the part in the vehicle height direction is approximately the same as the dimension of the crash box 30 in the vehicle height direction.

The first impact absorbing portion 31 has a generally rectangular shape extending in the vehicle longitudinal direction in plan view. The rear end of the first impact absorbing portion 31 is fastened to the front end of the side member SL. The front end of the first impact absorbing portion 31 is connected to the vehicle width direction intermediate portion (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 absorbing portion 31 (the center line in the vehicle width direction in plan view of the first impact absorbing portion 31) coincides with the vehicle longitudinal direction.

More specifically, as shown in FIG. 5, the first impact absorbing 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 front-rear 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 position of the inner wall portion 311 and the rear end position of 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 located in front of the side member SL. The rear end of the inner wall portion 311 and the rear end of the outer wall portion 312 are connected to the rear wall portion 313, and the front end of the inner wall portion 311 and the front end of the outer wall portion 312 are connected to the front wall portion 314. A through hole is formed in the rear wall portion 313, penetrating from its front surface to its rear surface. In addition, a flange portion 315 is formed at the front end of the inner wall portion 311, extending inward in the vehicle width direction (to the right in FIG. 5) along the rear surface of the bumper reinforcement 10. A through hole is formed in the flange portion 315, penetrating from its front surface to its rear surface.

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 center of the inner wall portion 311 in the front-rear direction and is connected to the outer wall portion 312.

The second impact absorbing portion 32 is formed on the outer side in the vehicle width direction (left side in FIG. 5) of the outer wall portion 312 of the first impact absorbing portion 31. The second impact absorbing portion 32 is substantially triangular in plan view. The front end portion of the second impact absorbing portion 32 is fastened to the left end portion in the vehicle width direction of the bumper reinforcement 10. The second impact absorbing portion 32 supports the left end portion in the vehicle width direction of the bumper reinforcement 10. The front end portion of the second impact absorbing portion 32 is not connected to the reinforcing member 20.

More specifically, the second impact absorbing section 32 includes an outer wall section 321 and a front wall section 314. The outer wall section 321 extends forward and outward (leftward) in the vehicle width direction from the rear end of the outer wall section 312 of the first impact absorbing section 31. The front-rear direction position of the tip (front end) of the outer wall section 321 is rearward of the front-rear direction position of the front end of the outer wall section 312. The front wall section 322 extends from the front end of the outer wall section 312 so as to follow the rear surface of the left end section of the bumper reinforcement 10. The tip of the outer wall section 321 is connected to the left end section of the front wall section 322.

A rib R2 is formed in the space surrounded by the outer wall portion 312, the outer wall portion 321, and the front wall portion 322. The rib R2 extends forward and outward in the vehicle width direction from the connection portion between the outer wall portion 312 and the outer wall portion 321, and is connected to approximately the center of the front wall portion 322. In addition, a flange portion 323 is formed at the front end of the outer wall portion 321, extending outward in the vehicle width direction (leftward in FIG. 5) along the rear surface of the bumper reinforcement 10. A through hole is formed in the flange portion 323, penetrating from its front surface to its rear surface.

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 of the crash box 30 is fastened to the bumper reinforcement 10 by the bolts. Also, bolts are inserted into the through holes formed in the rear wall portion 313, and the rear end of the crash box 30 is fastened to the front end surface of the side member SL by the bolts. The lower surface of the bumper reinforcement 10 and the lower surface of the crash box 30 are located in approximately the same plane. Also, the upper surface of the reinforcing member 20 and the upper surface of the crash box 30 are located in approximately the same plane. The left end of the bumper reinforcement 10 and the reinforcing member 20 overlap with the left half of the front surface of the front wall portion 322 of the second impact absorbing portion 32. That is, approximately half of the area of the front surface of the front wall portion 322 on the vehicle width direction end side cannot be seen from the front of the vehicle V, but the other areas of the front wall portion 322 are exposed. On the other hand, the bumper reinforcement 10 is parburlapped on the lower part of the front surface of the front wall part 314 of the first impact absorbing part 31. In other words, the lower part of the front wall part 314 cannot be seen from the front of the vehicle V, but the part above it is exposed.

(Action and Effects)
When an object OB collides with the front end of the vehicle V in an area to the left of the portion located in front of the side member SL, the object OB advances into 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 the process, the rear surface of the left end of the bumper reinforcement 10 in the vehicle width direction is supported by the second impact absorbing portion 32. The load acting on the left end of the bumper reinforcement 10 is applied (transmitted) to the front end surface of the side member SL mainly via the outer wall portion 321 and the rib R2 of the second impact absorbing portion 32. Then, a load (a component force 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 high strength against the load in its axial direction. Therefore, even if a load is applied to the front end surface of the side member SL through 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 lean slightly to the left, while the second shock absorbing portion 32 deforms so as to be pushed backward. In other words, the collision energy of the object OB is converted into deformation energy of the first shock absorbing portion 31 and the second shock absorbing portion 32 and is absorbed.

The load applied to all end faces of the side member SL (the load in the axial direction of the side member SL) changes as shown in the actual case in FIG. 8. That is, the load increases relatively rapidly immediately after the collision of the object OB. That is, as the amount of penetration (stroke) of the object OB increases, the load increases relatively rapidly and reaches a peak. Then, as the stroke increases further, the load decreases slightly, but a certain amount of the load is maintained. Here, the amount of impact absorption corresponds to the integral value of the load in the same figure. In this embodiment, the load increases relatively rapidly in the early stages of the collision, and thereafter, the load is maintained without decreasing much. Therefore, according to this embodiment, the impact can be efficiently absorbed.

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 a conventional bumper reinforcement. This prevents the peak value of the load applied to the side members SL, SR and the rate of increase in the load in the initial stage of the collision from becoming excessive when an object collides with the center portion in the vehicle width direction of the vehicle V.

The crash box 30 is also formed as a single unit using extrusion molding. This reduces the cost of managing parts compared to manufacturing the first shock absorbing section 31 and the second shock absorbing section 32 separately and then joining them together to form the crash box 30. This also reduces the number of manufacturing steps. As a result, the manufacturing cost of the shock absorbing device 1 is low.

Furthermore, the implementation of the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the purpose of the present invention.

For example, instead of the reinforcing member 20, a reinforcing member 40 may be adopted as shown in Figs. 9 to 12. The reinforcing member 40 is slightly elongated compared to the reinforcing member 20. That is, the width W40 of the reinforcing member 40 is smaller than the width _W10 of the bumper reinforcement 10. When the reinforcing member 40 is attached to the upper wall portion 13, the wall surface of the reinforcing member 40 facing forward is located rearward of the wall surface of the front wall portion 11 of the bumper reinforcement 10. In addition, in the example using the reinforcing member 20, one end of the reinforcing member 20 is located forward of the center portion in the vehicle width direction of the front wall portion 322, while one end of the reinforcing member 40 is located forward 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.

By using the reinforcing member 40, when an object collides with the center of the vehicle V in the vehicle width direction, it is possible to more effectively prevent the peak value of the load applied to the side members SL, SR and the rate at which the load increases in the initial stage of the collision from becoming excessive.

When the reinforcing member 40 is used, when the object OB collides with the left end of the vehicle V, the first impact absorbing portion 31 and the second impact absorbing portion 32 deform as shown in FIG. 12. At that time, the load acting on the side member SL changes as shown by the dashed line in FIG. 8. That is, in this case, the rate of increase in the load in the early stages of the collision is smaller than when the reinforcing member 20 is used. Also, the entry stroke of the object OB at the time when the load reaches its peak is larger than when the reinforcing member 20 is used. In this way, when the reinforcing member 40 is used, the change in the load in the early stages of the collision is gradual, so the impact on the occupants of the vehicle V can be reduced.

In addition, the above embodiment is an 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, but 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. In other words, it is sufficient that the end of the bumper reinforcement 10 and the reinforcing member 20 cover the entire front wall portion 322 (at least about half) when viewed from the front of the vehicle V.

1...shock absorbing device, 10...bumper reinforcement, 20...reinforcing member, 30...crash box, 40...reinforcing member, OB...object, SL, SR...side member, TH...through hole, V...vehicle

Claims (1)

An impact absorbing device provided in front of a side member extending in a vehicle front-rear direction,
A cylindrical bumper reinforcement extending in a vehicle width direction, the dimension of which in a vehicle height direction is smaller than the dimension of the side member in the vehicle height direction;
A reinforcing member attached to an upper side or a lower side of an end portion of the bumper reinforcement in a vehicle width direction and 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, supporting the bumper reinforcement and the reinforcing member, and deforming to absorb an impact when a rearward load acts on the bumper reinforcement;
Equipped with
The crash box is
a first impact absorbing portion disposed in front of the side member and extending forward from a front end of the side member;
a second impact absorbing portion disposed between an end portion of the bumper reinforcement in the vehicle width direction, the reinforcing member, and a front end of the side member, and extending forward and outward from the front end of the side member in the vehicle width direction;
Equipped with
The reinforcing member is a tubular member extending parallel to an extension direction of an end portion of the bumper reinforcement in a vehicle width direction, and is thinner than the bumper reinforcement .

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