Vehicle impact absorbing components

Abstract

To improve energy absorption performance.SOLUTION: A vehicle impact absorbing member 20 includes: a body part 40 that extends in a first direction (a front-rear direction L); and a receiving part 50 that covers a tip, in the first direction, of the body part 40 and is configured to receive a collision load. The receiving part 50 has rigidity lower than that of the body part 40.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an impact absorbing member for a vehicle. [Background technology]

[0002] Patent Document 1 discloses an energy absorption structure for a hollow cylindrical body made of metal or resin that receives a compressive load. The hollow cylindrical body has a trigger, a hollow cylindrical portion, and multiple grooves. The trigger is provided at the open end of the hollow cylindrical body and is inclined so that the closer it is to the open end, the more it is positioned toward the outer periphery. The hollow cylindrical portion is connected to the trigger on the side opposite the open end. The multiple grooves extend along the axial direction in the trigger and the hollow cylindrical portion and are spaced apart from each other in the circumferential direction. The portions of the grooves formed in the hollow cylindrical portion do not penetrate the hollow cylindrical portion in the thickness direction.

[0003] When an axial load acts on the hollow cylindrical body, a bending moment acts on the hollow cylindrical portion, and a tensile force acts in the circumferential direction to push open the groove. This causes cracks to form in the grooves of the hollow cylindrical portion. The axial load causes these cracks to propagate in the axial direction. Furthermore, the bending moment causes the trigger to bend from the open end toward the outer periphery, causing it to deform in a spiral shape. In this way, energy is absorbed by the spiral deformation and the propagation of the crack. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 10-19074 Summary of the Invention [Problem to be solved by the invention]

[0005] In the hollow cylindrical body described in Patent Document 1, the initial load increases rapidly when an axial load is applied, making the hollow cylindrical portion prone to buckling. Therefore, there is room for improvement in terms of energy absorption performance. [Means for solving the problem]

[0006] To solve the above problem, an impact absorbing member for a vehicle has a main body portion extending in a first direction and a receiving portion that covers the tip of the main body portion in the first direction and receives a collision load, and the receiving portion has lower rigidity than the main body portion. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a cross-sectional view of an impact absorbing member for a vehicle according to one embodiment. [Figure 2] FIG. 2 is a perspective view of the impact absorbing member for a vehicle shown in FIG. [Figure 3] FIG. 3 is a perspective view of the impact absorbing member for a vehicle shown in FIG. [Figure 4] 4 is a perspective cross-sectional view showing the layer structure of the main body of the impact absorbing member for a vehicle of FIG. [Figure 5] FIG. 5(a) is a cross-sectional view of the impact absorbing member before deformation, and FIG. 5(b) is a cross-sectional view of the impact absorbing member after deformation. [Figure 6] FIG. 6 is a graph showing the relationship between the displacement and the load of the impact absorbing members of this embodiment and the comparative example. [Figure 7] FIG. 7 is a graph showing the relationship between the displacement and the load of the impact absorbing members of this embodiment and the comparative example. [Figure 8] FIG. 10 is a perspective view of a shock absorbing member for a vehicle according to a first modified example. [Figure 9] FIG. 10 is a perspective view of a second modified example of an impact absorbing member for a vehicle. [Figure 10] FIG. 10 is a perspective view of a shock absorbing member for a vehicle according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0008] Hereinafter, one embodiment of a shock absorbing member for a vehicle (hereinafter referred to as a shock absorbing member 20) will be described with reference to FIGS. Hereinafter, the longitudinal direction of the vehicle will be referred to as the longitudinal direction L, the direction of the vehicle will be referred to as the vehicle width direction W, and the vertical direction of the vehicle when the vehicle is positioned on a horizontal plane will be referred to as the vertical direction Z. Furthermore, the front and rear sides in the longitudinal direction L will be referred to simply as the "front side" and the "rear side", respectively, and the upper and lower sides in the vertical direction Z will be referred to simply as the "upper side" and the "lower side", respectively.

[0009] 1, provided at the front of the vehicle are, in order from the front side, a bumper reinforcement 10, an impact absorbing member 20, and a front side member 11. That is, the impact absorbing member 20 is sandwiched between the bumper reinforcement 10 and the front side member 11 in the front-rear direction L.

[0010] As shown in FIGS. 1 to 3, the impact absorbing member 20 has a main body 40 extending in a first direction, and a receiving portion 50 that covers the tip of the main body 40 in the first direction and receives a collision load. The receiving portion 50 has lower rigidity than the main body 40. In this embodiment, the front-rear direction L corresponds to the first direction in [Means for Solving the Problems]. The impact absorbing member 20 also has a base portion 30 and a connecting portion 60.

[0011] Each component of the impact absorbing member 20 will be described in detail below. <Main body 40> 4, the main body 40 is preferably in the form of a plate in which a plurality of fiber-reinforced resin layers 41 formed by impregnating reinforcing fibers 42 with resin 43 are stacked on one another in a plane direction perpendicular to the first direction (front-rear direction L). Furthermore, the main body 40 preferably has a bent portion 44 that is bent in the plane direction.

[0012] The fiber reinforced resin layer 41 is formed by impregnating a plurality of reinforcing fibers 42 arranged in a sheet shape with a thermoplastic resin 43. The plurality of reinforcing fibers 42 constituting the fiber reinforced resin layer 41 are long fibers and extend in a single direction.

[0013] The reinforcing fibers 42 are preferably glass fibers, and the resin 43 is preferably polypropylene or nylon. The plurality of fiber reinforced resin layers 41 are welded to one another. It is preferable that the reinforcing fibers 42 of adjacent fiber reinforced resin layers 41 extend perpendicular to one another.

[0014] The cross section of the main body 40 in the above-mentioned plane direction is preferably an open cross section. 2 and 3, the cross-sectional shape of the main body 40 in the above-mentioned planar direction is the same throughout the first direction (front-rear direction L). The cross-sectional shape of the main body 40 in this embodiment is approximately W-shaped. The main body 40 has a total of six bent portions 44a to 44f.

[0015] <Receiving part 50> 1 to 3, the receiving portion 50 extends along the tip, i.e., the front end, of the main body portion 40. The receiving portion 50 is preferably provided over the entire extension direction of the tip of the main body portion 40. The receiving portion 50 of this embodiment is substantially W-shaped.

[0016] The receiving portion 50 has a cross-sectional shape that tapers toward the tip end in the first direction, i.e., toward the front. Specifically, the receiving portion 50 has a tip end surface 51 located at one end in the thickness direction of the main body 40, and an inclined surface 52 that continues to the other end of the tip end surface 51 in the thickness direction. The tip end surface 51 is located on a plane that is perpendicular to the first direction (front-rear direction L). In this embodiment, the tip end surface 51 is located on the outside of the W shape in the thickness direction.

[0017] The receiving portion 50 is preferably made of a thermoplastic resin. The thermoplastic resin is preferably the same as the resin 43, for example. <Base part 30> 1 to 3, the base portion 30 is provided at the base end of the main body portion 40 in the first direction, that is, at the rear end of the main body portion 40. The base portion 30 is preferably made of the same resin as the receiving portion 50.

[0018] The pedestal portion 30 has a base portion 31, a support protrusion 32, and a collar . The base portion 31 is in the shape of a substantially rectangular plate. The support protrusion 32 protrudes forward from the front surface of the base portion 31. The support protrusion 32 has a groove portion 33 in which the rear end portion of the main body portion 40 is received and fixed (see FIG. 1).

[0019] The base portion 31 and the support protrusion 32 are integrally molded from the above-mentioned resin. Cylindrical collars 34 that penetrate in the front-rear direction L are integrally provided at the four corners of the base portion 31. Bolts (not shown) for fixing the pedestal portion 30 to the front end surfaces of the front side members 11 are inserted into the collars 34.

[0020] <Connection part 60> 2 and 3, the connecting portion 60 connects the base portion 30 and the receiving portion 50. The connecting portion 60 is provided on the surface of the main body portion 40. The connecting portion 60 is preferably made of the same resin as the receiving portion 50.

[0021] The connecting portion 60 of this embodiment has two first connecting portions 61 and three second connecting portions 62. The first connecting portions 61 are provided one at each end in the extending direction of the main body portion 40 in the above-mentioned planar direction. The two first connecting portions 61 extend in the first direction.

[0022] The second connecting portions 62 are provided on the outer surfaces of the W-shape between the bent portions 44a and 44b of the main body portion 40, between the bent portions 44c and 44d of the main body portion 40, and between the bent portions 44e and 44f of the main body portion 40. The three first connecting portions 61 extend in the first direction.

[0023] Next, a manufacturing procedure for the impact absorbing member 20 of this embodiment will be described. First, the manufacturing procedure for the main body 40 will be described. A laminate is formed by welding together the plurality of fiber reinforced resin layers 41. Then, the laminate is heated and pressed with a press mold (both not shown), thereby forming the main body 40 having a bent portion 44 that is bent in the above-mentioned planar direction.

[0024] Next, with the main body 40 and collar 34 inserted into a mold, molten resin (all not shown) is injected into a cavity formed by the molding surface of the mold and the main body 40 and collar 34. As a result, the base 30, connecting portion 60, and receiving portion 50 are integrally molded on the surface of the main body 40.

[0025] Next, the operation of this embodiment will be described. When a vehicle collides head-on, the load associated with the collision (hereinafter referred to as collision load) acts on the receiving portion 50 via the bumper reinforcement 10. Here, since the tip of the main body portion 40 is covered by the receiving portion 50, which has lower rigidity than the main body portion 40, the receiving portion 50 creates a starting point for fracture in the main body portion 40. As a result, the initial load when the collision load is received is reduced compared to when the tip of the main body portion 40 is not covered by the receiving portion 50. This makes it possible to suppress buckling of the main body portion 40.

[0026] Here, since the cross section of the main body portion 40 in the above-mentioned planar direction is an open cross section, the main body portion 40 deforms so as to open outward from the state shown in Fig. 5(a) to the state shown in Fig. 5(b). Note that the receiving portion 50 is not shown in Fig. 5(b).

[0027] Next, with reference to FIGS. 6 and 7, the results of a compression test on the relationship between displacement and load for the impact absorbing member 20 of this embodiment and an impact absorbing member of a comparative example will be described. In Fig. 6, the load-displacement curve of the impact absorbing member 20 of this embodiment in a room temperature environment is shown by a solid line. Also in Fig. 6, the load-displacement curve of the impact absorbing member of the comparative example in a room temperature environment is shown by a dashed line. Also in Fig. 6, the load-displacement curve of the impact absorbing member of the comparative example when buckling occurs in a room temperature environment is shown by a dot-dash line. Note that the impact absorbing member of the comparative example differs from the impact absorbing member of this embodiment in that it does not have the receiving portion 50 and the connecting portion 60.

[0028] As shown in FIG. 6, according to the impact absorbing member 20 of this embodiment, the initial load can be reduced to about half of that of the impact absorbing member of the comparative example. In Figure 7, the load-displacement curve of the impact absorbing member 20 of this embodiment in a low-temperature environment is shown by a solid line. Also in Figure 7, the load-displacement curve of the impact absorbing member of the comparative example in a low-temperature environment is shown by a dotted line. Also in Figure 7, the load-displacement curve of the impact absorbing member of the comparative example in a normal temperature environment is shown by a dashed line. Note that the impact absorbing member of the comparative example differs from the impact absorbing member of this embodiment in that it does not have a receiving portion 50. Note that the low temperature in the low-temperature environment here is minus 30 degrees. Also, the normal temperature in the normal temperature environment is 23 degrees.

[0029] 7, when comparing the load-displacement curve of the comparative example in a low-temperature environment with the load-displacement curve of the comparative example in a room-temperature environment, it can be said that the initial load is larger in a low-temperature environment than in a room-temperature environment. In contrast, according to the impact absorbing member 20 of this embodiment, it can be said that the initial load is reduced compared to the impact absorbing member of the comparative example in a room-temperature environment.

[0030] Next, the effects of this embodiment will be described. (1) The impact absorbing member 20 has a main body 40 extending in a first direction and a receiving portion 50 that covers the tip of the main body 40 in the first direction and receives a collision load. The receiving portion 50 has lower rigidity than the main body 40.

[0031] According to this configuration, the tip of the main body 40 is covered by the receiving portion 50, which has lower rigidity than the main body 40, so when a collision load acts on the receiving portion 50, the receiving portion 50 becomes a starting point for fracture in the main body 40. As a result, the initial load when a collision load is applied is reduced compared to when the tip of the main body 40 is not covered by the receiving portion 50. This makes it possible to suppress buckling of the main body 40. Therefore, it is possible to improve energy absorption performance.

[0032] (2) The main body 40 is in the form of a plate in which a plurality of fiber-reinforced resin layers 41 formed by impregnating reinforcing fibers 42 with resin 43 are stacked on one another in a plane direction perpendicular to the first direction, and has a bent portion 44 that is bent in the plane direction. The cross section of the main body 40 in the plane direction is an open cross section.

[0033] With this configuration, the cross section of the main body 40 in the planar direction is an open cross section, so that the main body 40 deforms to open outward when subjected to a collision load. This increases the amount of displacement of the main body 40 in the first direction when subjected to a collision load, i.e., the stroke. This further improves energy absorption performance.

[0034] (3) The receiving portion 50 has a cross-sectional shape that tapers toward the tip in the first direction. With this configuration, when a collision load acts on the tip of the receiving portion 50, the main body 40 deforms in the thickness direction of the main body 40 toward the side where the tip of the receiving portion 50 is located. This promotes the deformation of the main body 40 so that it opens outward. Therefore, the energy absorption performance can be further improved.

[0035] (4) The receiving portion 50 is made of a thermoplastic resin. According to this configuration, the receiving portion 50 can be formed by insert molding, eliminating the need for a step of attaching the receiving portion 50 to the main body 40. Therefore, the impact absorbing member 20 can be easily formed.

[0036] (5) The base portion 30 is provided at the base end of the main body portion 40 in the first direction and is made of the same resin as the receiving portion 50, and the connecting portion 60 connects the base portion 30 and the receiving portion 50 and is made of the same resin as the receiving portion 50. The connecting portion 60 is provided on the surface of the main body portion 40.

[0037] With this configuration, the base portion 30 and the receiving portion 50 can be formed simultaneously by insert molding. In addition, since the base portion 30 and the receiving portion 50 are connected via the connecting portion 60, the receiving portion 50 can be firmly fixed to the main body portion 40 and the base portion 30.

[0038] <Example of change> The above embodiment can be modified as follows: The present embodiment and the following modifications can be combined with each other within the scope of technical compatibility.

[0039] Either the first connecting portion 61 or the second connecting portion 62 may be omitted. Both the first connecting portion 61 and the second connecting portion 62, i.e., the connecting portion 60, can be omitted.

[0040] The receiving portion 50 may be made of a material other than resin, such as rubber. In short, the receiving portion 50 may be made of any material as long as it has lower rigidity than the main body portion 40. 8, the tip surface 151 of the receiving portion 150 may be provided on the inside of the W shape in the plate thickness direction. The receiving portion 150 has an inclined surface 152 on the opposite side of the tip surface 151 in the plate thickness direction of the main body portion 40.

[0041] The receiving portion 50 is not limited to a cross-sectional shape that tapers toward the tip in the first direction. For example, as shown in FIG. 9, the tip surface 251 of the receiving portion 250 may have a notch 253 at a portion that overlaps with the bent portions 44a to 44f in the first direction. In this case, the notch 253 in the tip surface 251 of the receiving portion 250 becomes the starting point of fracture, which promotes deformation of the main body portion 40 so that it opens outward. This further improves energy absorption performance.

[0042] As shown in FIG. 10, the thickness of the receiving portion 350 in the first direction may be made larger toward the center of the width of the W-shape. In the above embodiment and each modified example, the cross-sectional shape of the main body portion 40 is exemplified as being W-shaped with two Vs lined up, but the cross-sectional shape of the main body portion can also be a "VVV" shape with three or more Vs lined up, or can be appropriately changed to a V-shape, U-shape, etc.

[0043] In the above embodiment and each modification, the bent portion is embodied as the bent portion 44, but the bent portion may not be bent. The cross section of the main body in the plane direction may be a closed cross section such as a circle.

[0044] Each of the above embodiments includes the configurations described in the following supplementary notes. [Appendix 1] An impact absorbing member for a vehicle, comprising: a plate-shaped main body portion extending in a first direction; and a receiving portion covering the tip of the main body portion in the first direction and receiving a collision load, wherein the receiving portion has lower rigidity than the main body portion.

[0045] [Appendix 2] The vehicle impact absorbing member described in [Appendix 1], wherein the main body portion is in the form of a plate in which a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with resin are stacked on top of each other, and has a bent portion that is curved in a planar direction perpendicular to the first direction, and the cross section of the main body portion in the planar direction is an open cross section.

[0046] [Appendix 3] The bending portion is a bending portion having a shape bent in the planar direction, and the tip surface of the receiving portion has a notch in the portion overlapping with the bending portion in the first direction. [Appendix 2] An impact absorbing member for a vehicle described in

[0047] [Appendix 4] The impact absorbing member for a vehicle according to [Appendix 2] or [Appendix 3], wherein the receiving portion is tapered toward the tip end in the first direction as it extends further outward from the open cross section.

[0048] [Appendix 5] The impact absorbing component for a vehicle according to any one of [Appendix 2] to [Appendix 4], wherein the receiving portion is made of resin.

[0049] [Appendix 6] [Appendix 5] An impact absorbing component for a vehicle as described in [Appendix 5], comprising: a base portion provided at the base end of the main body portion in the first direction and made of the same resin as the receiving portion; and a connecting portion connecting the base portion and the receiving portion and made of the same resin as the receiving portion, the connecting portion being provided on the surface of the main body portion. [Explanation of symbols]

[0050] 10...Bumper reinforcement 11...Front side member 20...Shock absorbing member 30...Base 31...Plate part 32...Support protrusion 33...Groove 34...Color 40...Main body 41...Fiber reinforced resin layer 42...Reinforced fiber 43...Resin 44a~44f...Bent section 50, 150, 250, 350... Receiving part 51,151,251…Tip surface 52,152…Slope surface 60...Connection part 61...1st connection part 62…Second connection part 253...Notch

Claims

1. a main body portion extending in a first direction; a receiving portion that covers a tip of the main body portion in the first direction and receives a collision load, the receiving portion has lower rigidity than the main body portion, The main body portion has a plate shape in which a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with resin are stacked on each other in a plane direction perpendicular to the first direction, and has a bending portion having a shape bent in the plane direction, a cross section of the main body in the planar direction is an open cross section, The bent portion is a bent portion having a shape bent in the surface direction, a tip end surface of the receiving portion having a notch at a portion overlapping the bent portion in the first direction; Impact absorbing components for vehicles.

2. A main body portion extending in a first direction; a receiving portion that covers a tip of the main body portion in the first direction and receives a collision load, the receiving portion has lower rigidity than the main body portion, The main body portion has a plate shape in which a plurality of fiber-reinforced resin layers formed by impregnating reinforcing fibers with resin are stacked on each other in a plane direction perpendicular to the first direction, and has a bending portion having a shape bent in the plane direction, a cross section of the main body in the planar direction is an open cross section, the receiving portion is made of a thermoplastic resin, a base portion provided at a base end of the main body portion in the first direction and made of the same resin as the receiving portion; a connecting portion that connects the base portion and the receiving portion and is made of the same resin as the receiving portion, The connecting portion is provided on the surface of the main body portion. Impact absorbing components for vehicles.

3. The receiving portion has a cross-sectional shape that tapers toward the tip side in the first direction. The impact absorbing member for a vehicle according to claim 1 or 2.

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