JP2019172019A - Rear bumper structure - Google Patents

Abstract

To provide a rear bumper structure which can inhibit a reflector attached to a rear bumper from falling during a vehicle rear end collision more than a conventional rear bumper structure.SOLUTION: A rear bumper structure includes: a rear end wall 26 forming a vehicle rear end; and a recessed part 22 which is recessed to the vehicle front side further than the rear end wall 26 and in which a reflector 30 is housed. In a portion of the rear end wall 26 located below the recessed part 22, a lightening part 26b is formed at a part of a rear surface 26a that is a vehicle front side surface.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a vehicle rear bumper structure.

  A rear bumper is provided at the rear end of the vehicle to absorb an impact at the time of a rear collision (rear collision). The rear bumper is provided with a reflector that is a reflector. Even when the vehicle is running with the rear lamp being unlit, the light from the headlamp of the rear vehicle is reflected by the reflector of the front vehicle, so that the rear vehicle can grasp the inter-vehicle distance from the front vehicle.

  For example, Chapter 581 of Title 49 of the Federal Regulations (CFR), a US law, sets standards for bumper impact durability against rear impact. According to the standard, it is required that the reflector is not damaged or the reflector is not dropped from the rear bumper at the time of a low-speed rear impact.

  In the rear impact test based on the above criteria, a so-called pendulum test is performed. A pendulum whose weight is a block of a predetermined weight is swung down from the rear of the vehicle and applied to the rear bumper. Thereafter, the reflector is inspected for breakage or dropout.

  In order to prevent such damage to the reflector in the rear impact test and the actual rear impact, for example, in Patent Document 1, as illustrated in FIG. 5, the rear bumper 100 is recessed forward of the rear end surface 102 of the vehicle. A recess 104 is formed, and the reflector 106 is accommodated in the recess 104. Specifically, the bottom wall 104 a that is the front end wall of the recess 104 and the base 110 of the reflector 106 are fastened by a screw 109. The rear end surface 112 (reflecting surface) of the reflector main body 108 has a layout that is drawn forward of the rear end surface 102 of the rear bumper 100, so that direct hitting of blocks and obstacles (barriers) can be avoided during a rear impact test or an actual rear impact.

JP2013-63729A

  By the way, since the recessed part recessed in front of the vehicle is formed in the rear bumper, the recessed part may collide with a vehicle member provided in front of the rear bumper prior to other parts of the rear bumper at the time of rear collision.

  For example, as illustrated in FIG. 5, a lower back panel 114 to which the rear bumper 100 is attached is disposed in front of the rear bumper 100 in the vehicle.

  As illustrated in FIG. 6, in the pendulum test, when the block 116 serving as a weight collides with the rear bumper 100, the rear bumper 100 is pushed forward of the vehicle. At this time, prior to other parts of the rear bumper 100, the bottom wall 104a of the recess 104, more precisely, the screw 109 screwed into the bottom wall 104a collides with the lower back panel 114.

  If the block 116 further enters the front of the vehicle after the screw 109 collides with the lower back panel 114, the recess 104 of the rear bumper 100 that is sandwiched between the lower back panel 114 and the block 116 may be buckled and damaged. is there. Due to the breakage of the recess 104, the fastening relationship with the reflector 106 is canceled, and the reflector 106 may fall off the rear bumper 100.

  In order to prevent the reflector 106 from falling off, it is conceivable that the distance between the screw 109 and the lower back panel 114 is larger than the stroke of the block 116 toward the front of the vehicle. However, in this case, the vehicle length (vehicle length) is increased by increasing the separation distance, and there is a risk of design restrictions when the vehicle length is kept within the dimensional standard.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a rear bumper structure that can suppress the drop-out of a reflector at the time of a rear collision more than before without accompanying the extension of the vehicle length.

  The present invention relates to a rear bumper structure. The structure includes a rear end wall serving as a rear end of the vehicle, and a recessed portion that is recessed forward of the vehicle from the rear end wall and accommodates the reflector. A portion of the rear end wall below the recess is formed with a thinned portion on a part of the rear surface, which is the front surface of the vehicle.

  According to the present invention, at the time of a rear collision, the rear end wall is crushed and deformed starting from a thinned portion that is a relatively weak portion, and absorbs the impact of the rear collision. As a result, it is possible to reduce the impact input to the concave portion, and it is possible to suppress the dropout of the reflector accompanying the breakage of the concave portion as compared with the conventional case.

It is a rear view which illustrates the vehicle carrying the rear bumper structure concerning this embodiment. It is a disassembled perspective view which illustrates each structure seen from the back surface (surface of the vehicle front side) of a rear bumper lower. It is AA sectional drawing when each structure of FIG. 2 is assembled | attached. It is side surface sectional drawing explaining the mode at the time of a pendulum test of the rear bumper structure which concerns on this embodiment. It is side surface sectional drawing which illustrates the conventional rear bumper structure. It is side surface sectional drawing explaining the mode at the time of a pendulum test of the conventional rear bumper structure.

  The rear bumper structure according to the present embodiment will be described with reference to FIGS. 1 to 4, the vehicle front-rear direction (hereinafter referred to as the vehicle length direction) is indicated by an axis represented by the symbol FR, and the vehicle width direction (hereinafter referred to as the vehicle width direction as appropriate) is represented by the symbol RW. The vertical direction (hereinafter referred to as the vehicle height direction as appropriate) is indicated by the axis represented by the symbol UP. Symbol FR is an abbreviation for Front, and the vehicle longitudinal axis FR is defined as a forward direction in front of the vehicle. The symbol RW is an abbreviation for Right Width, and the vehicle width direction axis RW has a right direction in the vehicle width as a positive direction. In addition, the vehicle height direction axis UP is the positive direction.

  FIG. 1 illustrates a rear view of a vehicle on which the rear bumper structure according to this embodiment is mounted. The rear bumper structure according to the present embodiment includes a rear bumper upper 10, a rear bumper lower 20, and a reflector 30. The rear bumper upper 10 and the rear bumper lower 20 may be integrally formed as a single member.

  The rear bumper upper 10 and the rear bumper lower 20 are both rear end members of the vehicle, and are buffer members that absorb an impact at the time of rear collision (rear collision). Both the rear bumper upper 10 and the rear bumper lower 20 extend over the entire width of the vehicle (the total length in the RW axial direction). The rear bumper upper 10 and the rear bumper lower 20 are formed through a molding process such as injection molding using a resin material such as polypropylene.

  Reflectors 30 are provided at both ends of the rear bumper 20 in the vehicle width direction. 2 and 3, peripheral views of the reflector 30 mounting portion of the rear bumper 20 are illustrated. FIG. 2 is an exploded perspective view illustrating each configuration when the rear bumper 20 is viewed from the back surface 26a that is the front surface of the vehicle. FIG. 3 is a cross-sectional view taken along the line AA when the components shown in FIG. 2 are assembled, and illustrates a cross section including a fastening structure in which the reflector 30 and the rear bumper 20 are fastened with screws 36.

  The reflector 30 includes a reflector body 32 having a reflective surface and a base 34 that supports the reflector body 32. The shape and the shape of the reflector 30 are determined by regulations and the like, and for example, as shown in FIG. 2, the reflector 30 is formed in a flat plate shape whose longitudinal direction is the vehicle width direction.

  The reflector body 32 and the base 34 are made of a resin material such as plastic, and both are joined by welding or the like. A reflecting surface 32a (see FIG. 3) of the reflector body 32 is used as a front surface, and a bottom surface 34a (see FIG. 2) of the base 34 which is the back surface opposite to the reflecting surface 32a is a fastening surface with the recess 22 formed in the rear bumper 20. .

  Specifically, a claw 34d and a fastening projection 34b project from the bottom surface 34a of the base 34 in the vehicle length direction. The claw 34d and the fastening projection 34b are provided at both ends of the base 34 in the vehicle width direction. A screw hole 34c is drilled in the fastening convex portion 34b in the vehicle length direction.

  The claw 34d is inserted and engaged in an engagement hole 22b formed in the recess 22 of the rear bumper lower 20. Referring to FIG. 3, the fastening projection 34 b is inserted into the fastening recess 24 of the rear bumper lower 20, and the screw hole 34 c of the fastening projection 34 b and the screw hole 24 b of the fastening recess 24 are aligned. Screws 36 are screwed into these screw holes 24b and 34c. In this way, the claws 34d are fitted into the engagement holes 22b, and the screws 30 are screwed into the screw holes 24b and 34c, whereby the reflector 30 is fastened to the rear bumper lower 20.

  Referring to FIG. 2, the rear bumper 20 has a rear end wall 26 extending substantially vertically (UP axis direction) and a lower end connected to the lower end of the rear end wall 26 and extending in the vehicle length direction (FR axis direction). A wall 28 is provided. The lower end wall 28 has a function of reducing air resistance and a design surface.

  With reference to FIG. 3, the rear bumper lower 20 is attached at a predetermined distance behind the lower back panel 40. More specifically, the rear end wall 26 of the rear bumper lower 20 is disposed behind the lower back panel 40. Further, the lower end wall 28 is arranged to be lower than the lower end of the lower back panel 40.

  2 and 3, the rear end wall 26 is disposed at the rear end of the vehicle, and collides with an obstacle (block or barrier) at the time of rear collision. As will be described later, when the rear end wall 26 is crushed and deformed at the time of a rear collision, the collision impact is absorbed, and the drop of the reflector 30 from the rear bumper lower 20 is suppressed.

  The rear end wall 26 is formed with a recess 22 in which the reflector 30 is accommodated. The recess 22 is recessed forward of the vehicle from the rear end wall 26. The recess 22 is formed such that the depth L1 (see FIG. 2) of the recess is larger than the thickness L2 of the reflector 30 (L1> L2).

  By setting the depth L1 of the recess 22 to the thickness L2 of the reflector 30, as shown in FIG. 3, the reflecting surface 32a of the reflector 30 is drawn forward of the vehicle from the rear end wall 26 of the rear bumper lower 20. Arrangement. Thereby, the reflector 30 can avoid a direct hit of a block or a barrier at the time of a rear collision.

  The recess 22 is formed according to the shape of the reflector 30. For example, as illustrated in FIG. 2, according to the shape of the reflector 30 whose longitudinal direction is the vehicle width direction, the recess 22 also has a groove shape whose longitudinal direction is the vehicle width direction.

  An engagement hole 22 b and a fastening recess 24 are formed in the bottom of the recess 22, in other words, the bottom wall 22 a provided at the forefront of the recess 22 as a mechanism for engaging with the reflector 30. The engagement hole 22b is a through hole that penetrates the bottom wall 22a in the vehicle length direction, and the claw 34d of the reflector 30 is inserted into the engagement hole 22b as described above.

  The fastening recess 24 is a recess protruding further forward of the vehicle than the recess 22, and the fastening protrusion 34 b of the reflector 30 is inserted into this recess. A screw hole 24b is passed through the bottom wall 24a of the fastening recess 24 in the vehicle length direction. As described above, the screw hole 24b of the fastening recess 24 and the screw hole 34c of the reflector 30 are aligned, and the screw 36 is screwed.

  As shown in FIGS. 2 and 3, the bottom of the fastening recess 24, in other words, the bottom wall 24 a provided in the forefront in the vehicle length direction of the fastening recess 24 is a lower back of each portion of the rear bumper lower 20. This is the part closest to the panel 40. As will be described later, the bottom wall 24a of the fastening recess 24 collides with the lower back panel 40 (more precisely, via the screw 36) before any member of the rear bumper lower 20 at the time of rear collision.

  A thinned portion 26b is formed in a part of the rear surface 26a of the rear end wall 26 on the front side of the vehicle. The thinned portion 26b is a portion that is thinner than the periphery thereof, and has a relatively thin wall thickness. Since the wall thickness is reduced, the rigidity of the part is relatively low. That is, the thinned portion 26b functions as a fragile portion, and becomes a deformation starting point at the time of a rear collision, and promotes the crushing deformation of the rear end wall 26.

  The lightening part 26b may have the same size in the vertical direction (UP axis direction) and the horizontal direction (RW axis direction), but it is preferable that the horizontal direction is long. For example, as shown in FIG. 2, the lightening portion 26 b may be a slit cut in the vehicle width direction on the back surface 26 a of the rear end wall 26. The thinned portion 26 b is formed so as to substantially coincide with the vehicle width direction of the recess 22. Further, the lightening portion 26 b may be formed in a portion of the rear end wall 26 below the recess 22.

  Further, the cutout portion 26b may have a semicircular cross section or a triangular shape. That is, it is preferable to determine the size and shape of the lightening portion 26b based on the result of the rear impact test for the rear bumper 20.

  If the thinned portion 26b is formed on the surface 26c (see FIG. 3), which is the design surface of the rear end wall 26, there is a risk of undesirable effects on the design (appearance) such as the reflection of light being disturbed by the thinned portion 26b. There is. On the other hand, since the lightening portion 26b according to the present embodiment is formed on the back surface 26a of the rear end wall 26, there is an advantage that it is not necessary to restrict the design.

  Further, a plurality of the lightening portions 26 b may be provided on the back surface 26 a of the rear end wall 26. Since the thinned portion 26b functions as a starting point of the deformation of the rear end wall 26, in other words, a collapse hinge, in order to intend the collapsed shape of the rear end wall 26, a plurality of the thinned portions 26b are provided. May be formed.

  For example, when the rear end wall 26 has a mountain shape, the lightening portion 26b may be provided on the back surface 26a of the portion corresponding to the apex. Moreover, you may provide the thinning part 26b in the boundary part which connects the lower end of the rear end wall 26, and the rear end of a lower end wall.

  FIG. 4 shows an example when a pendulum test is performed on the rear bumper structure according to the present embodiment. As described above, the block 42 having a predetermined weight and shape is swung down from a predetermined height and collides with the rear end wall 26 of the rear bumper lower 20. At this time, the rear bumper 20 is pushed forward in the vehicle length direction as the block 42 advances. By this pushing, the head of the screw 36 screwed into the fastening recess 24 collides with the lower back panel 40.

  When the block 42 further enters the front in the vehicle length direction, the rear end wall 26 is crushed and deformed starting from the thinned portion 26b of the rear end wall 26. The crushing deformation absorbs the impact and reduces the transmission of the impact load to the fastening recess 24. As a result, buckling damage of the fastening recess 24 is avoided.

10 rear bumper upper, 20 rear bumper lower, 22 recess, 22a bottom wall of recess, 22b engagement hole of recess, 24 fastening recess, 24a bottom wall of fastening recess, 24b screw hole of fastening recess, 26 rear end wall, 26a rear end Back surface of the wall, 26b Thinned portion, 26c Surface of the rear end wall, 28 Lower end wall, 30 Reflector, 32 Reflector body, 32a Reflective surface, 34 Base, 34a Base bottom surface, 34b Fastening convex portion, 34c Fastening convex portion screw Hole, 34d claw, 40 lower back panel, 42 blocks.

Claims (1)

A rear end wall as a rear end of the vehicle,
A recess recessed in the front of the vehicle from the rear end wall, in which the reflector is accommodated,
A rear bumper structure comprising:
In the lower portion of the rear end wall below the concave portion, a lightening portion is formed on a part of the rear surface which is a surface on the vehicle front side.
Rear bumper structure.