JP2007131040A - Rear part vehicle body structure of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide rear part vehicle body structure of a vehicle capable of preventing an opposite vehicle from getting on rear side members of the own vehicle when the own vehicle is collided from behind. <P>SOLUTION: The rear side members 4 extending in the longitudinal direction of the vehicle 1 is disposed at both right and left sides of the vehicle 1. Bumper reinforcement 12 is fixed to the rear ends of these rear side members 4 through a crash box 11 so as to connect respective rear side members 4 each other. A high-strength part 13 and a low-strength part 14 having a lower strength than that of the high-strength part 13 are formed at the rear end parts of the rear side members 4. The high-strength part 13 is formed at the area including the rear end upper parts of the rear side members 4, and the low-strength part 14 is formed at the area on the lower side of the high-strength part 13 at the rear end parts of the rear side members 4. The reinforcement 15 for giving a strength difference to form the high-strength part 13 is disposed inside of the rear end parts of the rear side members 4. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a rear body structure of a vehicle including a rear side member extending in the front-rear direction of the vehicle.

As a conventional rear body structure of a vehicle, for example, as disclosed in Patent Document 1, a substantially U-shaped side member reinforcement is housed and fixed inside a substantially U-shaped rear side member. ing.
JP-A-8-276820

  However, in the above-described conventional rear body structure, both side walls of the side member reinforcement are formed so as to rise from the rear end side of the vehicle along the front direction, so that the strength of the rear end upper portion of the rear side member is increased. It is weaker than the strength of the lower part of the rear end. For this reason, for example, when a large vehicle makes a rear-end collision (rear collision) at the rear of the host vehicle, the rear side member of the host vehicle cannot exert a sufficient reaction force against the partner vehicle, and the partner vehicle does not move on the rear side member of the host vehicle. There is a risk of getting on.

  An object of the present invention is to provide a rear body structure of a vehicle that can suppress the ride-on of the opponent vehicle onto the rear side member of the own vehicle when the own vehicle is rear-ended.

  The present invention relates to a rear body structure of a vehicle including a rear side member extending in the front-rear direction of the vehicle, wherein the region including the rear end upper portion of the rear side member constitutes a high strength portion, and the high strength portion at the rear end portion of the rear side member The lower region constitutes a low-strength portion having a lower strength than the high-strength portion.

  When, for example, a large-sized vehicle comes into the rear of the host vehicle having such a rear body structure, a low-strength portion having low strength is first deformed in the rear end portion of the rear side member of the host vehicle. The low-strength portion is formed in a lower region of the rear side member including the rear end upper portion. Therefore, by deforming such a low strength portion, a force that pushes the rear end portion of the rear side member upward is applied to the rear side member. In this case, since the load receiving part of the rear side member with respect to the opponent vehicle spreads upward, the input of the opponent vehicle is received by the rear side member. Thereby, for example, even if the opponent vehicle is a large vehicle, the opponent vehicle can be prevented from riding on the rear side member of the own vehicle.

  Preferably, the boundary between the high-strength portion and the low-strength portion extends obliquely upward toward the rear end side of the rear side member, and the vertical width of the low-strength portion increases toward the rear end side of the rear side member. It is getting bigger. In this case, when the low-strength portion of the rear side member is deformed by the rear collision of the host vehicle, a force that pushes the rear end of the rear side member upward is effectively applied to the rear side member. Become.

  Preferably, a buckling member having a lower strength than the rear side member is fixed to the rear end of the rear side member. In this case, when the low-strength portion of the rear side member is deformed by the rear impact of the host vehicle, the buckling member is rotated and moved downward while being crushed along with the deformation of the low-strength portion. For this reason, the rear end of the rear side member is pushed up more effectively, and the input of the opponent vehicle is sufficiently received by the rear end of the rear side member and the buckling member.

  Further preferably, a reinforcing member extending in the front-rear direction of the rear side member is attached to a front portion of the low-strength portion of the rear side member. In this case, when the host vehicle is rearwardly impacted, the reinforcing member is axially broken to effectively absorb the collision energy.

  Preferably, a strength difference imparting reinforcing member that forms a high strength portion is attached to a region including the rear end upper portion of the rear side member, and the strength difference imparting reinforcing member is provided at the rear end portion of the rear side member. The region on the side constitutes the low strength part. In this case, the high-strength portion and the low-strength portion can be easily formed at the rear end portion of the rear side member only by adding one reinforcing member.

  Further, the low strength portion may be formed of a plate material thinner than the plate material forming the high strength portion. In this case, the high-strength portion and the low-strength portion can be easily formed at the rear end portion of the rear side member only by changing the plate thickness of the plate material forming the rear side member.

  ADVANTAGE OF THE INVENTION According to this invention, when the own vehicle is collided rearward, the climbing of the other party vehicle on the rear side member of the own vehicle can be suppressed. As a result, it is possible to efficiently absorb an impact when the host vehicle is impacted rearward.

  Hereinafter, a preferred embodiment of a rear body structure of a vehicle according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic side view showing a first embodiment of a rear body structure of a vehicle according to the present invention, and FIG. 2 is a plan view of the rear body structure shown in FIG. In each figure, the vehicle 1 includes a skeleton member 3 that constitutes a part of the vehicle body 2.

  The skeleton member 3 is disposed on both the left and right sides of the vehicle 1, and extends in the left-right direction (vehicle width direction) of the vehicle 1. The pair of rear side members 4 extends in the front-rear direction of the vehicle 1. It has two rear cross members 5 to be connected. Each rear side member 4 is coupled to a rocker (side sill) 10 including a side member outer panel and a floor side inner. Each rear side member 4 has a bent portion 4p on the side where it is connected to the rocker 10, and the rear side member 4 is higher than the rocker 10 by this bent portion 4p. Further, the front end side portion of each rear side member 4 extends obliquely so as to open outward toward the front of the vehicle 1. The rockers 10 on both the left and right sides are connected by a center cross member 6.

  The rear side member 4 is fixed to the lower surface of the rear floor panel 7 (see FIGS. 3 and 4). A rear seat 8 is disposed on the upper portion of the rear floor panel 7. A spare tire 9 is housed below the rear floor panel 7 at the rear of the vehicle 1.

  A bumper reinforcement 12 is fixed to the rear ends of the left and right rear side members 4 via a crash box 11 so as to connect the rear side members 4 to each other. The strength of the crash box 11 and the bumper reinforcement 12 is lower than the strength of the rear side member 4.

  At the rear end portion of the rear side member 4, a high strength portion 13 and a low strength portion 14 having a lower strength than the high strength portion 13 are formed. The high strength portion 13 is formed in a region including the upper rear end portion of the rear side member 4, and the low strength portion 14 is formed in a region below the high strength portion 13 in the rear end portion of the rear side member 4.

  The lower surface of the rear end portion of the rear side member 4 extends obliquely downward toward the rear end side of the rear side member 4. That is, the rear end portion of the rear side member 4 is configured such that the width in the vertical direction increases from the front end side to the rear end side of the rear side member 4. The boundary P between the high strength portion 13 and the low strength portion 14 extends obliquely upward toward the rear end side of the rear side member 4. Thereby, the vertical width of the low-strength portion 14 increases from the front end side to the rear end side of the rear side member 4.

  The rear side member 4 is formed of a steel plate material such as high tensile strength steel which is light and high strength iron. As shown in FIG. 3, the rear side member 4 has a substantially U-shaped cross section including a bottom plate portion 4a, a side plate portion 4b, and a flange portion 4c. The flange portion 4c is joined to the lower surface of the rear floor panel 7 by welding or the like. ing.

  Inside the rear end portion of the rear side member 4 is disposed a reinforcement (reinforcing member) 15 for imparting a strength difference that forms the high strength portion 13 described above. The reinforcement 15 is formed of a steel plate material having the same type and thickness as that of the rear side member 4 or a steel plate material having a type and thickness different from those of the rear side member 4. As shown in FIG. 3, the lean reinforcement 15 has a U-shaped cross section including a bottom plate portion 15a and side plate portions 15b. The side plate portion 15b is coupled to the side plate portion 4b of the rear side member 4 by welding or the like. At this time, the bottom plate portion 15a extends obliquely upward toward the rear end side of the rear side member 4. Thus, by providing the reinforcement 15 for imparting the strength difference, the high-strength portion 13 and the low-strength portion 14 can be easily formed at the rear end portion of the rear side member 4.

  The low-strength portion 14 is located in the lower region of the reinforcement 15 at the rear end portion of the rear side member 4. The crushing characteristics of the cross section of the low-strength portion 14 are determined so that the crushing strength is higher than that of the crash box 11. And when the impact load of the slow collision (damager) area | region is input into the rear part of the vehicle 1, the crash box 11 is crushed and absorbs impact energy, and the low intensity | strength part 14 is comprised so that it may not deform | transform easily. Yes. Further, the strength of the rear end portion of the rear side member 4 and the reinforcement 15 is determined from the relationship between traction and securing during transportation.

  Inside the rear side member 4, a lean force absorption 16 for absorbing collision energy that extends to the bent portion 4 p in the front-rear direction of the rear side member 4 is disposed in front of the reinforcement 15. The lean reinforcement 16 is formed of a steel plate material having the same type and thickness as that of the rear side member 4 or a steel plate material having a type and thickness different from those of the rear side member 4. As shown in FIG. 4, the reinforcement 16 has a U-shaped cross section including a bottom plate portion 16 a and a side plate portion 16 b, and the side plate portion 16 b is welded to a lower portion of the side plate portion 4 b of the rear side member 4. Are connected. The lean reinforcement 16 may be separated from the lean reinforcement 15 as shown in FIG. 1 or may be brought into contact with the lean reinforcement 15.

  Next, in the vehicle 1 having the rear vehicle body structure configured as described above, a state when the large vehicle 17 has a rear impact (rear impact) as shown in FIG. 5A will be described.

  The height position of the bumper reinforcement 18 of the large vehicle (damaging vehicle) 17 is higher than the height position of the bumper reinforcement 12 of the vehicle (damaged vehicle) 1. For this reason, when the large vehicle 17 collides with the vehicle 1, as shown in FIG. 5B, the large vehicle 17 enters the vehicle 1 while crushing the upper part of the bumper reinforcement 12 and the crash box 11 of the vehicle 1. Come on.

  At that time, the collision load is transmitted to the bumper reinforcement 12 obliquely downward through the contact surface with the bumper reinforcement 18 of the large vehicle 17. As a result, as shown in FIG. 6A, the crash box 11 and the bumper reinforcement 12 rotate and move downward while being crushed and then bend down. Further, the low strength portion 14 provided at the rear end portion of the rear side member 4 is deformed (collapsed). At this time, since the boundary P between the high-strength portion 13 and the low-strength portion 14 extends obliquely so as to increase toward the rear end side of the rear side member 4, the crash box 11 or the like is caused by the deformation of the low-strength portion 14. It will efficiently rotate downward.

  Then, due to the downward bending moment generated at this time, as shown in FIG. 6B, the rear side of the rear side member 4 is pushed upward, and the rear side member 4 assumes a forward leaning posture. In this state, the crash box 11 and the bumper reinforcement 12 serve as a collision load receiving surface (transmission surface). For this reason, since the contact position of the rear side member 4 and the harming vehicle 17 moves upward, the input from the bumper reinforcement 18 of the harming vehicle 17 is efficiently received by the rear side member 4. Thereby, the rear side member 4 can give sufficient reaction force with respect to the harm vehicle 17, and generation | occurrence | production of the attack vehicle 17 on the rear side member 4 (override) is prevented.

  When the injurious vehicle 17 further enters, as shown in FIG. 7, the reinforcement 16 attached to the rear side member 4 is axially compressed and effectively absorbs the collision energy. Here, when the breaking strength of the lean reinforcement 16 is set to such a level that the bumper reinforcement 18 and the crash box of the harm vehicle 1 are crushed, the rear side member 4 of the victim vehicle 1 and the harm vehicle Since the 17 rear side members are crushed together, it is possible to disperse the collision energy in both vehicles and absorb it more effectively.

  Here, as a comparative example, an example of a conventional rear body structure is shown in FIG. In the same figure, the low-strength portion 14 as in the present embodiment is not particularly provided at the rear end portion of the rear side member 4. Specifically, a lean reinforcement 50 is disposed inside the rear end portion of the rear side member 4, and the lean reinforcement 50 is provided so as to cover almost the entire rear end portion of the rear side member 4. Yes. Since the reinforcement 16 is provided in the lower part of the rear side member 4 in addition to such a reinforcement 50, the cross-sectional strength distribution of the rear side member 4 is such that the upper side is weak and the lower side is strong. become.

  When the large vehicle 17 collides with the vehicle 51 having such a rear body structure, the bumper reinforcement 18 of the harm vehicle 17 enters the vehicle 51 while crushing the upper body 52, and rides on the floor of the vehicle 51. come.

  At this time, the rear end portion of the rear side member 4 is pushed down and further bent downward. Then, the harming vehicle 17 enters while the upper body 52 of the damaged vehicle 51 is crushed so that the bumper reinforcement 18 and the front side member of the harming vehicle 17 slide on the upper part of the rear side member 4. Therefore, as a result, the rear side member 4 cannot function as a collision energy absorbing member.

  On the other hand, in this embodiment, since the lower portion is configured to be weaker than the upper portion as the cross-sectional strength distribution of the rear end portion of the rear side member 4, the large vehicle 17 is caused to collide with the vehicle 1. When this happens, as described above, the crash box 11 of the damaged vehicle 1 is rotated and bent downward. For this reason, since the load transmission surface of the damaged vehicle 1 with respect to the harming vehicle 17 becomes wider in the vertical direction, the input from the harming vehicle 17 is sufficiently received. Thereby, since it is possible to suppress the overriding of the harmful vehicle 17 on the rear side member 4 of the damaged vehicle 1, it is possible to efficiently absorb the collision energy when the large vehicle 17 collides with the vehicle 1.

  FIG. 9 is a schematic side view showing a second embodiment of a rear body structure of a vehicle according to the present invention. In the figure, the same or equivalent members as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  In the figure, the rear vehicle body structure of the present embodiment includes a rear side member 20 instead of the rear side member 4 in the first embodiment. A rear end portion of the rear side member 20 is provided with a high strength portion 21 and a low strength portion 22 having a strength lower than that of the high strength portion 21. The high strength portion 21 and the low strength portion 22 are formed in the same region as the high strength portion 13 and the low strength portion 14 of the rear side member 4 in the first embodiment.

  The rear side member 20 is integrally formed of the same type of steel plate material as that of the rear side member 4 described above. As shown in FIG. 10, the rear side member 20 has a substantially U-shaped cross section including a bottom plate portion 20a, a side plate portion 20b, and a flange portion 20c. The flange portion 20c is joined to the lower surface of the rear floor panel 7 by welding or the like. ing. In the rear side member 20, the thickness of the steel sheet material constituting the low strength portion 22 is smaller than the thickness of the steel sheet material constituting other portions including the high strength portion 21. Accordingly, the high strength portion 21 and the low strength portion 22 can be formed at the rear end portion of the rear side member 20 without separately using components such as a reinforcement.

  Also in this embodiment, since the in-section strength distribution of the rear end portion of the rear side member 20 is configured such that the lower portion is weaker than the upper portion, the vehicle 1 is a large vehicle. When a rear impact occurs, a large vehicle can be prevented from riding on the rear side member 20 of the vehicle 1.

  The present invention is not limited to the above embodiment. For example, the shapes of the high-strength portion and the low-strength portion provided at the rear end portion of the rear side member are not particularly limited to those in the above embodiment. If the rear end of the rear side member is designed to be pushed up by deformation of the low-strength portion when the vehicle is bumped rearward, for example, most of the width in the vertical direction of the low-strength portion may be made equal. .

  As an example, a modification of the first embodiment is shown in FIGS. 12A is a cross-sectional view taken along the line XX of FIG. 11, and FIG. 12B is a cross-sectional view taken along the line YY of FIG. In each figure, the vertical width of the rear end portion of the rear side member 4 is generally the same. In addition, a lean reinforcement 30 is disposed in the rear end portion of the rear side member 4 instead of the lean reinforcement 15 described above. In the reinforcement 30, the height dimension of the portion (the rear end side portion) forming the high strength portion 13 and the low strength portion 14 is equal toward the rear end side of the rear side member 4. Thereby, most of the vertical widths of the low-strength portions 14 are equal.

  In the above embodiment, the high-strength portion and the low-strength portion are formed at the rear end portion of the rear side member by attaching a reinforcement to the rear side member or changing the thickness of the steel plate material forming the rear side member. In addition to this, the high-strength portion and the low-strength portion may be formed by, for example, forming a notch or the like in the rear side member or changing the type of the plate material forming the rear side member.

1 is a schematic side view showing a first embodiment of a rear body structure of a vehicle according to the present invention. FIG. 2 is a plan view of the rear vehicle body structure shown in FIG. 1. It is the III-III sectional view taken on the line of FIG. It is the IV-IV sectional view taken on the line of FIG. FIG. 2 is a schematic side view showing a state when a large vehicle has collided with the vehicle shown in FIG. 1. FIG. 2 is a schematic side view showing a state when a large vehicle has collided with the vehicle shown in FIG. 1. FIG. 2 is a schematic side view showing a state when a large vehicle has collided with the vehicle shown in FIG. 1. As a comparative example, it is a schematic side view showing a state when a large vehicle rear-ends on a vehicle having a conventional rear body structure. It is a schematic side view which shows 2nd Embodiment of the rear part vehicle body structure concerning the present invention. FIG. 10 is a sectional view taken along line XX in FIG. 9. It is a schematic side view which shows the modification of 1st Embodiment of the rear part vehicle body structure concerning the present invention. It is the XX sectional view taken on the line of FIG. 11, and the YY sectional view.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2 ... Vehicle body, 4 ... Rear side member, 11 ... Crash box (buckling member), 12 ... Bumper force (buckling member), 13 ... High strength part, 14 ... Low strength part, 15 ... Strength Reinforcement for imparting a difference (reinforcing member for imparting strength difference), 16 ... Leanforce for absorbing collision energy (reinforcing member), 20 ... Rear side member, 21 ... High strength portion, 22 ... Low strength portion.

Claims (6)

In the rear body structure of the vehicle provided with a rear side member extending in the longitudinal direction of the vehicle,
The region including the rear end upper part of the rear side member constitutes a high strength part,
A rear body structure of a vehicle, wherein a region below the high-strength portion at a rear end portion of the rear side member constitutes a low-strength portion having a lower strength than the high-strength portion. The boundary between the high strength portion and the low strength portion extends obliquely upward toward the rear end side of the rear side member,
The rear body structure of the vehicle according to claim 1, wherein a width of the low-strength portion in a vertical direction increases toward a rear end side of the rear side member.   The rear body structure of the vehicle according to claim 1, wherein a buckling member having a lower strength than the rear side member is fixed to a rear end of the rear side member.   The rear body of the vehicle according to any one of claims 1 to 3, wherein a reinforcing member extending in the front-rear direction of the rear side member is attached to a front portion of the low-strength portion of the rear side member. Construction. In a region including the rear end upper part of the rear side member, a reinforcing member for imparting a strength difference that forms the high strength portion is attached,
The vehicle according to any one of claims 1 to 4, wherein a lower region of the reinforcing member for imparting a difference in strength at a rear end portion of the rear side member constitutes the low strength portion. Rear body structure. 5. The rear body structure of a vehicle according to claim 1, wherein the low-strength portion is formed of a plate material thinner than a plate material forming the high-strength portion.

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