JP5522191B2 - Vehicle shock absorption structure - Google Patents

Description

  The present invention relates to a shock absorbing structure for a vehicle.

  Conventionally, generally, in the front part of a vehicle, a metal-made hollow cylindrical shock absorbing member (crash box) is interposed between the bumper-in hose and the side member. In this type of vehicle impact absorbing structure, the impact absorbing member can be crushed in the axial direction to absorb the impact load at the time of collision. Such a shock absorbing structure is disclosed in Patent Document 1, for example.

  The shock absorbing performance is indicated by a compressive load as a reaction force against the displacement of the shock absorbing member. And, in the shock absorbing structure of the vehicle, it is not preferable that the compressive load jumps temporarily at the beginning of the collision by applying a sudden force from the viewpoint of protecting the collision control of the pedestrian or the like. It is desirable to keep it as constant as possible.

  Therefore, in order to prevent the compression load from jumping up at the start of the collision, Patent Document 1 has the following configuration. That is, as shown in FIG. 12, the shock absorbing member 311 has a hollow rectangular tube shape, and its rear end surface is flat perpendicular to the axial direction and is closed by the flat plate-like second plate 313. Thus, the entire surface is grounded to the side member 321 via the second plate 313. On the other hand, the end surface on the front side has a shape in which a part of a flat surface orthogonal to the axial direction is obliquely cut off, and is closed by a bent plate-shaped first plate 315. Then, only a part of the end surface (contact surface portion 311a) is connected to the bumper inhose via the first plate 315, and the inclined surface portion 311b is separated from the bumper inn hose. According to Patent Document 1, the inclined surface portion 311b that is separated from the bumper inn hose 323 is provided at the front end of the shock absorbing member 311 to reduce the transmission area of the collision load from the bumper inn hose to the shock absorbing member. Therefore, it is supposed that the compressive load at the initial stage of the collision is prevented from becoming particularly large, and the deformation that occurs so as to be crushed from the tip of the impact absorbing member proceeds in a stable manner in order.

  On the other hand, in Patent Document 2, the hollow cylindrical impact absorbing member is grounded to the bumper inn hose or the side member at the front and rear end surfaces thereof, but by inserting columnar wood therein In addition, it is said that it is possible to suppress the jump of the compression load at the initial stage of the collision and to suppress the subsequent fluctuation of the compression load.

JP 2005-271858 A JP 2001-182769 A

  Wood has a porous cell wall that is aligned in one direction, and is porous with pores aligned in one direction, and is reinforced with fibers in the one direction. Therefore, if the fiber direction is matched with the compression direction, the pores are crushed sequentially in the axial direction. Therefore, as compared with the case where the shock absorbing member is composed only of the hollow cylindrical body, the use of wood makes it possible to suppress the fluctuation of the compressive load and to obtain the shock absorbing member having excellent shock absorbing efficiency. However, when the impact is absorbed by the block-shaped wood, since the cross-sectional area is larger than that of the hollow cylinder, the compressive load is likely to jump up at the beginning of the collision when a force is suddenly applied and the wood starts to collapse. For this reason, the compressive load temporarily becomes high at the beginning of the collision, and changes stably after being lowered to some extent.

  On the other hand, even a shock absorbing member having only a hollow cylindrical body can absorb a certain amount of shock if it can be crushed in a bellows shape straight in the axial direction. However, if the center of gravity of the load is deviated, it will buckle and bend, and its function cannot be exhibited accurately. Therefore, in Patent Document 1, by forming the inclined surface portion 311b separated from the bumper inn hose at the front end of the shock absorbing member 311, the impact load is directly applied from the bumper inn hose 323 to the shock absorbing member 311. Although the transmitted area is reduced, by extending the first plate 315 to the inclined surface portion 311b, an impact load is applied uniformly to the entire end surface including the inclined surface portion 311b via the first plate 315. It has become. Therefore, even if the configuration of such a hollow cylindrical impact absorbing member is applied to an impact absorbing member made of wood, the cross-sectional area is larger than that of the hollow cylindrical body, particularly when block-like wood is used. Even the surface portion receives the load through the first plate 315, so that the compressive load is likely to jump up at the initial stage of the collision. In other words, as long as the impact load is applied to the entire front end face of the shock absorbing member, there is no substantial difference from the case where the bumper-in hose is entirely grounded, and the jumping of the compression load at the start of the collision cannot be reduced. .

  Accordingly, an object of the present invention is to provide a shock absorbing structure for a vehicle in which the compression load is prevented from jumping up at the start of a collision and the fluctuation of the compression load is smaller.

  The present invention is a vehicle impact absorbing structure including an impact absorbing member that receives an impact at the time of a vehicle collision as a compressive load in an axial direction between a bumper member and a vehicle skeleton member, and the impact absorbing member includes: Columnar wood, the fiber direction of which is parallel to the axial direction, and one end surface of the shock absorbing member is connected to only one of the bumper member or the vehicle skeleton member, and the shock absorbing member The other end surface of the member is connected to the other of the bumper member or the other vehicle skeleton member so as to be able to support the whole, and the impact absorbing member has a compressive load with only a part of the one end surface at the start of the collision. The shock absorbing structure of the vehicle is characterized in that it is locally compressed and deformed, and finally undergoes the local compressive deformation and finally the one end surface receives a compressive load as a whole. Here, “a part of one end face” of the shock absorbing member is connected to one of the bumper member or the vehicle skeleton member, and one end face is one end of the columnar shock absorbing member. Is composed of one plane, it means that one plane, and when one end of a columnar shock absorbing member is cut into two or more planes, all the planes of two or more planes are It is also the concept of using one end face. Further, being connected includes both a case where they are directly connected and a case where they are connected indirectly. Further, the impact absorbing member receiving an impact as an axial compressive load includes not only the case where the axial direction and the compressing direction are exactly the same, but also a case where they are slightly shifted. Further, the fiber direction of the wood constituting the shock absorbing member being parallel to the axial direction includes not only a case where the fiber is just parallel, but also a substantially parallel state with a slight deviation.

  According to the impact absorbing structure for a vehicle having such a configuration, when an impact is applied to the bumper member, the impact absorbing member made of wood compresses and deforms in the axial direction to absorb the impact. At that time, first, at the start of the collision, in the impact absorbing member, the compressive load is concentrated on a part of the end face where only a part of the shock absorbing member is connected to the bumper member or the vehicle frame member. As a result, the shock absorbing member is locally compressed and deformed in the axial direction from a part of one end face where the compressive load is concentrated. Therefore, the impact is absorbed only by a part of the cross section orthogonal to the axial direction. In this way, the shock absorbing member is locally compressed and deformed because the wood originally has an extremely strong bond in the fiber direction (longitudinal direction) compared to the direction orthogonal to the fiber (lateral direction), and columnar wood. This is because if only a part of the end face is pressed in the fiber direction, only that part is compressed and deformed in the axial direction. The impact absorbing member, after undergoing local compressive deformation, finally receives the compressive load as a whole and efficiently absorbs the impact across the entire cross section perpendicular to the axial direction. According to the shock absorbing structure of the present invention, the compressive load is reduced to the same level as when the entire subsequent compressive deformation is caused by the compressive deformation of the shock absorbing member locally at the start of the collision, in which the compressive load is likely to jump up. To reduce the fluctuation of the compression load.

  The one end surface of the shock absorbing member includes a connection surface portion that comes into contact with one of the bumper member or the vehicle skeleton member, and a separation surface portion spaced from one of the bumper member or the vehicle skeleton member. preferable. In this case, since one end surface of the shock absorbing member is directly connected to the bumper member or the vehicle frame member, connection with a small number of parts is possible.

  In addition, the one end face of the shock absorbing member is connected to one of the bumper member or the vehicle skeleton member via an interposed member, and the interposed member is higher in rigidity than the shock absorbing member. It is also preferable that an impact transmitting portion is provided, and the impact transmitting portion is disposed so as to overlap with only a part of the one end face of the impact absorbing member. In this case, it is possible to make one end surface of the impact absorbing member into a simple shape, and processing can be facilitated, and at the same time, cracking of wood during cutting can be reduced. In particular, when one end face of the shock absorbing member is formed by only one plane orthogonal to the axial direction, that is, when it is formed by a cut surface orthogonal to the fiber direction, only when cutting wood. Even when compressively deformed, it is difficult to break, and the shock absorbing performance can be stabilized.

  In the vehicle impact absorbing structure of the present invention, it is preferable that the one end face of the shock absorbing member is connected to the bumper member, and the other end face is connected to the vehicle skeleton member. In this case, the end surface on the base end side opposite to the end surface on the bumper member side where the impact of the impact absorbing member is input is connected to the vehicle skeleton member as a whole, and the impact absorbing member falls over during compression deformation. Hateful. Therefore, the shock absorbing member can be more reliably compressed and deformed in the axial direction, and the shock absorbing performance can be more easily exhibited.

  ADVANTAGE OF THE INVENTION According to this invention, it can suppress that the initial compressive load jumps up, and can provide the impact-absorbing structure of a vehicle with smaller fluctuation | variation of a compressive load.

It is a top view which shows typically the shock absorption structure of the vehicle which concerns on Embodiment 1 of this invention. It is a perspective view of the impact-absorbing member which concerns on Embodiment 1 of this invention. It is sectional drawing of the whole impact-absorbing structure corresponding to the III-III cross section of the impact-absorbing member shown by FIG. 2, (A) shows the aspect before a collision, (B) shows the shock-absorbing aspect in the initial stage of a collision, (C) shows the final shock absorption mode. It is a top view which shows typically the shock absorption structure of the vehicle which concerns on Embodiment 2 of this invention. It is a perspective view of the impact-absorbing member which concerns on Embodiment 2 of this invention. It is sectional drawing of the whole impact-absorbing structure corresponding to the VI-VI cross section of the impact-absorbing member shown by FIG. 5, (A) shows the aspect before a collision, (B) shows the shock-absorbing aspect in the initial stage of a collision, (C) shows the final shock absorption mode. It is a perspective view of the impact-absorbing member which concerns on Embodiment 3 of this invention. It is sectional drawing of the whole impact-absorbing structure corresponding to the VIII-VIII cross section of the impact-absorbing member shown by FIG. 7, (A) shows the aspect before a collision, (B) shows the shock-absorbing aspect in the initial stage of a collision, (C) shows the final shock absorption mode. It is a perspective view of the impact-absorbing member which concerns on Embodiment 4 of this invention. It is sectional drawing of the whole impact-absorbing structure corresponding to XX cross section of the impact-absorbing member shown by FIG. 9, (A) shows the aspect before a collision, (B) shows the shock-absorbing aspect in the initial stage of a collision, (C) shows the final shock absorption mode. It is sectional drawing which shows the impact-absorbing structure which concerns on the modification 1 of Embodiment 3 of this invention corresponding to FIG. 8 (A). It is a top view which shows the conventional impact-absorbing structure in a partial cross section. FIG. 3 is a schematic diagram showing a test 1 shock absorption performance test method. It is a graph which shows the relationship between the displacement of an impact-absorbing member and the compressive load as reaction force about the impact-absorbing structure of Example 1. It is a graph which shows the relationship between the displacement of an impact-absorbing member and the compressive load as a reaction force about the impact-absorbing structure of Comparative Example 1. FIG. 6 is a schematic diagram showing a test 2 shock absorbing performance test method. It is a graph which shows the relationship between the displacement of an impact-absorbing member, and the compressive load as a reaction force about the impact-absorbing structure of Example 2. It is a graph which shows the relationship between the displacement of an impact-absorbing member and the compressive load as a reaction force about the impact-absorbing structure of Comparative Example 2.

<Embodiment 1>
An embodiment of the present invention will be described with reference to FIGS. In the impact absorbing structure for a vehicle according to the present embodiment, an impact absorbing member 21 is disposed between the bumper-in hose 11 and the side member 13. First, the configuration of this shock absorbing structure will be described. Note that F and R indicated by arrows in the drawing indicate the front and rear of the vehicle, and C indicates the width direction of the vehicle (vehicle width direction).

  The bumper-in hose 11 is a cylindrical rigid body made of an extruded material of aluminum alloy, steel, or the like, and is disposed along the vehicle width direction at the front portion of the vehicle body. The center in the longitudinal direction extends straight along the vehicle width direction, and both ends are inclined rearward. The bumper inhose 11 corresponds to the bumper member of the present invention. In the present embodiment, the shock absorbing member 21 is disposed behind the portion 11a that extends straight along the vehicle width direction of the bumper inhose 11.

  The side members 13 are cylindrical rigid bodies made of steel or the like, and are arranged in pairs along the vehicle front-rear direction so as to be separated from each other in the width direction and constitute a skeleton of the vehicle.

  The shock absorbing member 21 is made of columnar wood W. The wood W is sawn so that its fiber direction is parallel to the axial direction. The kind of wood W is not specifically limited, For example, conifers, such as a cedar, a cypress, and a pine, and broad-leaved trees, such as a zelkova and a beech, can be used. Wood with a high specific gravity is excellent in strength, and wood with a low specific gravity has a high porosity, so that the crash stroke (displacement due to compression) is long. Considering this point, it is desirable to select wood having an appropriate specific gravity according to the installation position of the vehicle. Use of wood having a specific gravity of 0.2 to 0.4 is preferable because it can increase the amount of impact energy absorbed by having a certain degree of strength while sufficiently securing the crash stroke. Examples of the wood having a specific gravity of 0.2 to 0.4 include cedar, hinoki and pine.

  As shown in FIG. 2 and FIG. 3A, the shock absorbing member 21 of the present embodiment is a quadrangular prism having a regular square cross section perpendicular to the axial direction, and one end portion in the axial direction is partly It is a shape that is cut off at an angle. One end surface 23 of the shock absorbing member 21 is configured by a contact surface portion 23a made of a quadrangular surface orthogonal to the axial direction and a separation surface portion 23b made of a quadrangular surface inclined obliquely with respect to the axial direction. The other end face 25 of the shock absorbing member 21 is formed by a single plane of a regular square orthogonal to the axial direction.

  A hollow rectangular tubular frame 31 is fitted on the outside of the shock absorbing member 21. In other words, the shock absorbing member 21 is accommodated in the frame body 31. The frame 31 can support the shock absorbing member 21 and can be crushed in the axial direction together with the shock absorbing member 21 at the time of a vehicle collision. For example, the frame 31 is made of a metal such as aluminum, copper, or iron. .

  The shock absorbing member 21 is arranged so that one end surface 23 having a contact surface portion 23a and a separation surface portion 23b is on the bumper inn hose 11 side and the other end surface 25 is on the side member 13 side. The bumper rein hose 11 side end surface 23 of the shock absorbing member 21 is held in a state where only the contact surface part 23 a is in contact with the flat rear surface of the bumper rein hose 11, and the separation surface part 23 b is separated from the bumper rein hose 11. It is in a separated state. The method for fixing the shock absorbing member 21 to the bumper inhose 11 is not particularly limited. For example, the frame body 31 can be fixed to the bumper-in hose 11 by welding or adhesion. In addition, the shock absorbing member 21 can be fixed to the bumper-in hose 11 by screwing the frame body 31 to the bumper-in hose 11 via a mounting bracket.

  The shock absorbing member 21 is arranged coaxially with the side member 13. A support plate 27 is interposed between the end surface 25 on the side member 13 side of the shock absorbing member 21 and the side member 13, and the end surface 25 of the shock absorbing member 21 is entirely in contact with the support plate 27. It is held in the state. The support plate 27 is a rigid body that can receive the load of the shock absorbing member 21 without being easily deformed when the vehicle collides, and is made of a steel plate or the like. The support plate 27 is a flat plate having a larger area than the end surface 25 of the shock absorbing member 21, and the center is a support portion 27 a that covers the entire other end surface 25 of the shock absorbing member 21 as shown in FIG. And a margin as a connecting portion 27b with the side member 13 is left on the entire periphery. The method for fixing the impact absorbing member 21 to the support plate 27 is not particularly limited. For example, the frame 31 can be fixed by joining the support 31 to the support plate 27 by welding or adhesion. In addition, the shock absorbing member 21 can be fixed to the support plate 27 by screwing the frame 31 to the support plate 27 via a mounting bracket. The connection method between the support plate 27 and the side member 13 is not particularly limited, but the connecting portion 27b of the support plate 27 and the flange 13f provided at the tip of the side member 13 are brought into contact with each other and fastened, or joined by welding or adhesion. be able to.

  Next, the shock absorbing mechanism of this shock absorbing structure will be described. At the time of a frontal collision of the vehicle, as indicated by the white arrow in FIG. 1, when an impact from the front is applied to the bumper rein hose 11, the bumper rein hose 11 and the side member 13 are sandwiched between them. The impact absorbing member 21 is crushed to absorb the impact. At that time, as shown in FIG. 3A, at the start of the collision, the shock absorbing member 21 is in contact with the bumper inn hose 11 from the end surface 23 on the bumper inn hose 11 side before the collision. The compressive load is concentrated on the contact surface portion 23a. Then, the impact absorbing member 21 is crushed in the axial direction from the contact surface portion 23a where the compressive load is concentrated, and absorbs the impact only by a part of the cross section orthogonal to the axial direction. This is because the impact absorbing member 21 is made of wood W, and the fiber direction thereof is parallel to the axial direction (load direction). This is because wood W originally has a porous cell wall aligned in one direction, a porous structure in which pores align in one direction, and is reinforced with fibers in the one direction. Therefore, when the fiber direction and the axial direction are parallel, when one end face 23 in the axial direction receives a compressive load only at a part thereof (contact surface part 23a), from the part (contact surface part 23a) that has received the compressive load. The pores are crushed sequentially in the fiber direction (axial direction) and partially densified. FIG. 3B schematically shows the densified portion with shading. As described above, when the impact absorbing member 21 starts to collide, first, the shock absorbing member 21 is locally compressed and deformed from the contact surface portion 23a that has received the compressive load in a concentrated manner. The separation surface portion 23b is also in contact with the bumper-in hose 11 and receives an impact on the entire end surface 23 as shown in FIG. Thus, the compression deformation region in the cross section orthogonal to the axial direction of the shock absorbing member 21 gradually increases, and finally the entire cross section orthogonal to the axial direction is compressively deformed.

  According to such a shock absorbing structure, at the start of the collision, the shock is absorbed by only a part of the cross section orthogonal to the axial direction, and finally the shock is absorbed as a whole. The load can be prevented from jumping up at the start of the collision, and the impact can be absorbed efficiently while suppressing the fluctuation of the compression load.

<Embodiment 2>
Another embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 4, the present embodiment is different from the first embodiment in that the shock absorbing member 41 is disposed behind the portions 11 b that are inclined rearward of both ends of the bumper inhose 11. ing. Hereinafter, the differences will be mainly described, and the same configurations as those of the first embodiment are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

  The shock absorbing member 41 of the present embodiment is also made of columnar wood W. As shown in FIG. 5, the shape is a square shape in which the end surface 43 on the bumper reinhose 11 side is inclined with respect to the axial direction in a quadrangular prism with a square cross section orthogonal to the axial direction. It has become. Of the two planes constituting the end surface 43 on the bumper inhose 11 side, one constitutes a contact surface portion 43a that is arranged in contact with the bumper inhose 11, and is arranged away from the bumper inhose 11. The separation surface portion 43b is configured. Note that the end surface 45 on the side member 13 side of the shock absorbing member 41 is also configured as a single plane orthogonal to the axial direction in this embodiment, and the form of connection to the side member 13 is the same as in the first embodiment.

  Thus, even when the contact surface portion 43a is inclined with respect to the axial direction of the shock absorbing member 41, the basic shock absorbing mechanism is the same as that of the first embodiment. That is, as shown in FIG. 6A, the shock absorbing member 41 receives a compressive load intensively at the contact surface portion 43a in contact with the bumper-in hose 11 at the start of the collision, and the compressive load is concentrated. The portion (contact surface portion 43a) is sequentially compressed and deformed in the axial direction, and the impact is absorbed by only a part of the cross section orthogonal to the axial direction. As the compressive deformation progresses, the compressive deformation area increases, and finally, the cross section orthogonal to the axial direction compresses and deforms to absorb the impact as a whole.

<Embodiment 3>
Another embodiment of the present invention will be described with reference to FIGS. Although the present embodiment is the same as the first embodiment in that the shock absorbing member 51 is arranged behind the portion 11a that extends straight along the vehicle width direction of the bumper-in hose 11, the shock absorbing member 51 is similar to the first embodiment. The difference is that a bracket 61 is interposed between the member 51 and the bumper-in hose 11. Hereinafter, the differences will be mainly described, and the same configurations as those of the first embodiment are denoted by the same reference numerals in the drawings, and detailed description thereof will be omitted.

  The shock absorbing member 51 of the present embodiment is also made of columnar wood W. As shown in FIG. 7, the shape is a quadrangular prism with a square cross section orthogonal to the axial direction, and the end surface 53 on the bumper inn hose 11 side is formed by a single plane orthogonal to the axial direction. . Further, the end surface 55 on the side member 13 side is also configured by a single plane orthogonal to the axial direction, and the connection form to the side member 13 is the same as in the first embodiment.

  The bumper rein hose 11 side end surface 53 and the bumper rein hose 11 are connected via a bracket 61 interposed therebetween. The bracket 61 is a rigid body that is not easily deformed at the time of a vehicle collision, and is made of a steel material or the like. The bracket 61 corresponds to an intervention product of the present invention, and the illustrated portion corresponds to an impact transmission portion. The shape of the bracket 61 of this embodiment is a flat rectangular parallelepiped, and as shown in FIG. 8 (A), the opposing one surface 63 is connected to the bumper-in hose 11, and the other surface 65 is the shock absorbing member. 51 is in contact with the end face 53 on the bumper inhose 11 side. The bracket 61 is disposed so as to overlap only a part of the end surface 53 of the shock absorbing member 51 on the bumper inn hose 11 side. Therefore, the end surface 53 of the shock absorbing member 51 is formed with a contact surface portion 53 a that is in contact with the bracket 61 and a separation surface portion 53 b that is not in contact with the bracket 61. The method for fixing the bracket 61 to the bumper in hose 11 is not particularly limited, and for example, the bracket 61 may be fixed by joining or welding with welding or adhesion. Further, the method for fixing the shock absorbing member 51 to the bracket 61 is not particularly limited. For example, the frame body 31 can be fixed to the bracket 61 by welding or bonding or by screwing.

  Even in such a shock absorbing structure, the basic shock absorbing mechanism is the same as that of the above embodiment, and the shock absorbing member 51 is a part of the end surface 53 on the bumper innose 11 side where compressive load is concentrated ( The deformation is locally deformed from the contact surface portion 53a), and the impact is absorbed by only a part of the cross section orthogonal to the axial direction. Finally, the entire end surface 53 receives the compressive load and absorbs the shock by the entire cross section orthogonal. To do. In other words, at the start of the collision, if an impact is applied to the bumper-in hose 11, the impact is transmitted to the impact absorbing member 51 through the bracket 61. At this time, the shock absorbing member 51 receives a compressive load only on the contact surface portion 53a in contact with the bracket 61 of the end surface 53 on the bumper inn hose 11 side, and sequentially in the axial direction from the portion receiving the compressive load. Compressive deformation. Therefore, as shown in FIG. 8B, the bracket 61 is recessed in the axial direction from the contact surface portion 53 a with respect to the shock absorbing member 51. When the entire thickness of the bracket 61 is recessed into the shock absorbing member 51, the bumper in hose 11 comes into contact with the shock absorbing member 51 as shown in FIG. Thus, the entire end face 53 on the bumper inhose 11 side is pushed. For this reason, the entire cross section of the shock absorbing member 51 orthogonal to the axial direction is compressed and deformed.

  Thus, when the shape of the shock absorbing member 51 is a simple quadrangular prism and both end faces are made of a single plane orthogonal to the fiber direction, the wood W can be easily cut and the fiber direction can be reduced. Compared to the case of cutting obliquely, defects such as cracks are less likely to occur during processing. In addition, it is difficult to break even during compression deformation, and the shock absorbing performance can be exhibited stably.

<Embodiment 4>
Another embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the shock absorbing member 51 made of a simple quadrangular prism-shaped wood W as in the third embodiment is used, and the shock absorbing member 51 is used as the bumper in hose 11 as in the second embodiment. The rear part of the part 11b which inclines backward of the both ends of is arranged.

  Also in this embodiment, a bracket 71 made of a rigid body is interposed between the bumper-in hose 11 and the shock absorbing member 51. In the bracket 71, a surface 73 on the bumper innose 11 side is inclined along the bumper innose 11, and a contact surface 75 with the shock absorbing member 51 is set to face the surface 73. The contact surface 75 with respect to the shock absorbing member 51 is in contact with only a part of the end surface 53 of the shock absorbing member 51.

  The bracket 71 of this embodiment is accompanied by a protective cover 77 that covers the end surface 53 of the shock absorbing member 51 along the contact surface 75 with the shock absorbing member 51. The protective cover 77 protrudes from the contact surface 75 of the bracket 71 with respect to the shock absorbing member 51, and covers the separation surface portion 53 b of the end surface 53 of the shock absorbing member 51 that is not in contact with the bracket 71. The protective cover 77 protects the shock absorbing member 51 during normal use of the vehicle, and is soft or fragile to such an extent that the shock absorbing member 51 is not deformed when the vehicle collides. For example, it can be composed of a soft metal thin plate such as aluminum. In this case, when the vehicle collides, as shown in FIGS. 10B and 10C, no impact is transmitted from the soft protective cover 77 to the shock absorbing member 51, and the end surface 53 of the shock absorbing member 51 starts at the beginning. The bracket 71 is partially pushed, and then the bracket 71 and the bumper inn hose 11 are pushed. Therefore, the shock absorbing structure of this embodiment also exhibits the same function as that of the third embodiment.

  The protective cover 77 may be formed of, for example, a resin plate or the like, and may be broken and separated from the bracket 71 when the bracket 71 starts to be sunk into the shock absorbing member 51 and is strongly pressed against the shock absorbing member 51. Good.

<Other embodiments>
As shown in FIG. 11, when the bracket 61 (71) is interposed between the bumper-in hose 11 and the shock absorbing member 51 as in the third or fourth embodiment, the separation surface portion 53b is inclined. You may let them. In this case, when 11 comes into contact with the shock absorbing member 51 after the bracket 61 is completely indented into the shock absorbing member 51, the contact area gradually increases, so that the fluctuation of the compressive load is easily made smoother.

  Further, the bracket 61 may have a size that does not protrude from the end surface 53 as long as it overlaps a part of the end surface 53 of the shock absorbing member 51. However, when the bracket 61 protrudes from the shock absorbing member 51, the contact area of the bracket 61 with respect to the bumper inn hose 11 is large, and therefore the bumper inn hose supported by the side member 13 through the shock absorbing member 51. 11 is preferable because it does not wobble and is stably connected.

  In each of the above-described embodiments, the end surface of the impact absorbing member on the bumper inn hose 11 side is connected to the bumper inn hose 11 at a part thereof. However, the impact absorbing member is reversed to the side member 13 side. It is good also as a structure which the end surface of connects to the side member 13 in the part.

  Below, the result of having evaluated the shock absorption performance by the shock absorption structure of this invention is demonstrated. In each test, as a shock absorbing member, a cedar made of a square columnar shape so that the fiber direction is parallel to the axial direction was used, and this was accommodated in a square cylindrical frame made of aluminum (A5052). It was used for.

(Test 1)
In Test 1, as shown in FIG. 13, a rigid bumper-in hose was prepared as a simulated bumper member 111 in which the left and right ends of a 35 mm-thick aluminum square tube made of aluminum A5052 were inclined 10 ° inward. Then, the shock absorbing performance when the shock absorbing members 41, 41 were arranged on the inclined portion 111b at the end of the simulated bumper 111 was evaluated. The shock absorbing members were prepared in pairs in Example 1 and Comparative Example 1 having different surface shapes on the simulated bumper 111 side.

[Example 1]
In Example 1, a specific sample having the same shape as the shock absorbing member 41 shown in FIG. 5 was used as the shock absorbing member. The impact absorbing member of Example 1 is a 14.7 mm square × 70 mm axial length square material, with one end cut in the axial direction without changing the length, and the contact surface portion 43 a and the separation surface portion to the simulated bumper 111. 43b. The contact surface portion 43a is inclined by 10 °, and the separation surface portion 43b is inclined by 15 °.

[Comparative Example 1]
As the impact absorbing member of Example 1, a square material of 14.7 mm square × 70 mm in the axial direction is cut obliquely so that one end in the axial direction is inclined by 10 ° without changing the length, and the entire end face is simulated. An impact absorbing member that contacts the bumper member 111 was prepared.

  Each of the prepared shock absorbing members was accommodated in a square cylindrical frame having a thickness of 0.5 mm and an outer dimension of 16 mm square. Then, as shown in FIG. 13, the pair of shock absorbing members 41, 41 of Example 1 or Comparative Example 1 are set apart from each other on a flat test table S made of a rigid body, and are symmetrical on the left and right. In this manner, the simulated bumper 111 was placed and adhered and fixed, and both slope portions 111b of the simulated bumper 111 were supported by the impact absorbing member. Then, using a compression tester (Autograph AG-100kNE type) manufactured by Shimadzu Corporation, the center of the simulated bumper 111 was pressed in parallel with the axial direction of the shock absorbing member at a speed of 2 mm / min. Then, both the shock absorbing members were compressed and deformed straight in the axial direction. The relationship between the displacement and the compressive load at this time was measured. The results are shown in FIG. 14 for Example 1 and FIG. 15 for Comparative Example 1.

  As is clear from the results, in Comparative Example 1 in which the entire end face is in contact with the simulated bumper, the compression load slightly decreases after the compression load increases immediately after starting to compress, and then a little. Although there was up and down, it was almost stable (Fig. 15). On the other hand, in Example 1, which is connected to the simulated bumper in a state where it is in contact with only a part, the compression load does not increase temporarily immediately after starting to compress, and it becomes impossible to compress any more immediately after starting compression. The compression load was extremely stable until (FIG. 14).

(Test 2)
In Test 2, the impact absorbing performance was evaluated when the impact absorbing member was disposed in a portion of the bumper member extending straight in the vehicle width direction. As shown in FIG. 16, a rigid bumper-in hose made of a straight block made of aluminum A5052 having a thickness of 35 mm was prepared as the simulated bumper member 211. Further, as a shock absorbing member, a specific sample having the same shape as that of the shock absorbing member 51 shown in FIG. The prepared shock absorbing member was a square material of 29.4 mm square × 70 mm in the axial direction. The shock absorbing member was housed in a rectangular cylindrical frame having a wall thickness of 0.8 mm and an outer dimension of 31.6 mm square for the test.

[Example 2]
In Example 2, as shown in FIG. 16, a square-shaped rigid ring 213 made of aluminum A5052 was prepared as a simulated bracket interposed between the simulated bumper 211 and the impact absorbing member. In addition, the shape of the simulated bracket is a square shape because it is loaded on the compression tester when evaluating the shock absorbing performance of the shock absorbing structure in which the bracket is interposed between the bumper member and the shock absorbing member. This is to prevent the testing machine from stopping the test due to the shift of the center of gravity of the load. The dimensions of the B-shaped rigid ring 213 are an inner dimension of 24 mm square, an outer dimension of 33 mm square, and a thickness of 3 mm. A shock-absorbing member was erected on a flat test table S, and a square-shaped rigid ring 213 was placed on the shock-absorbing member so that the axial centers thereof coincided with each other. As a result, on the end face of the shock absorbing member, each side of the four circumferences is in a state of being 2.7 mm wide and in contact with the square-shaped rigid ring 213. Further, a simulated bumper member 211 was placed thereon. Then, using the impact compression tester (IM10T-20HV) manufactured by IMATEK, the center of the simulated bumper 211 was pressed parallel to the axial direction of the shock absorbing member at a speed of 5.41 m / sec. Then, the shock absorbing member was directly compressed and deformed. The relationship between the displacement and the compressive load at this time was measured. The result is shown in FIG.

[Comparative Example 2]
In Comparative Example 2, a rigid thick plate made of aluminum A5052 without a hole in the center of a 33 mm square and a thickness of 3 mm is used as a simulated bracket instead of the square-shaped rigid ring, and the entire end face of the shock absorbing member is made of aluminum A5052. The test was conducted in the same manner as in Example 2 in a state where the plate was in contact with the rigid board. As a result, the impact absorbing member of Comparative Example 2 was directly compressed and deformed. The result of measuring the relationship between the displacement and the compressive load at this time is shown in FIG.

  As is apparent from the results, in Comparative Example 2 in which the simulated bracket is arranged in contact with the entire end face of the shock absorbing member, immediately after the compression starts, the compression load suddenly increases and then rapidly decreases. Stable (Figure 18). On the other hand, in Example 2 where the simulated bracket is arranged in contact with only a part of the end surface of the shock absorbing member, the compression load does not increase temporarily immediately after the compression starts, and immediately after the compression starts. The compression load was very stable until no further compression was possible (FIG. 17).

11 Bumper Inn Hose 13 Side Member 21 Shock Absorbing Member 23 End Surface 23a (Bumper In Hose Side) Contact Surface Part 23b Separating Surface Part 25 End Side 27 (Side Member Side) Support Plate 41 Shock Absorbing Member 43 (Bumper Inn Hose Side) End surface 43a contact surface portion 45 end surface 51 (on the side member side) shock absorbing member 53 end surface 53a (on the bumper in-hose side) contact surface portion 53b spacing surface portion 55 (on the side member side) end surface 61 bracket 71 bracket W wood

Claims (1)

Between the bumper member and the vehicle both skeletal members, a shock absorber for a vehicle equipped with a shock absorbing member for receiving the impact of a vehicle collision as a compression load in the axial direction,
The shock absorbing member is a columnar wood, the fiber direction is parallel to the axial direction,
Wherein one end face of the shock absorbing member is connected via only surface contact portion thereof to one of said bumper member and the vehicle frame member,
Wherein is supported capable connected via a surface contact the other end surface of the impact absorbing member on the other hand the whole of the bumper member or the vehicle frame member,
The impact absorbing member is locally deformed by compression under compressive load only a portion of the one end face at the start collision, ultimately through said local compression deformation in the entire end face of the one Under compressive load ,
The one end face of the shock absorbing member is formed by only one plane orthogonal to the axial direction, and is connected to one of the bumper member or the vehicle skeleton member via an interposed object,
The intervening object has an impact transmission portion having rigidity higher than that of the impact absorbing member, and the impact transmitting portion is arranged to overlap with only a part of the one end surface of the impact absorbing member. Vehicle shock absorption structure.

Images