JP6680444B2 - Reinforcement structure of rear side member - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a reinforcing structure for left and right rear side members extending in a vehicle front-rear direction on a vehicle rear side.

  Patent Document 1 discloses a vehicle body rear portion including left and right rear floor side members (rear side members) extending substantially in the vehicle front-rear direction on both sides of the vehicle body rear portion, and a rear floor cross member (rear cross member) provided between the left and right rear side members. A structure is disclosed. In an automobile, a lean reinforcement (reinforcing member) is provided on a rear side member and a rear cross member in order to secure rigidity of a rear portion of a vehicle body.

JP, 2010-76472, A

  When a reinforcing member is provided in a part along the longitudinal direction of the rear side member, the difference in rigidity becomes large at the boundary portion of the rear side member where the reinforcing member is provided and where the reinforcing member is not provided. It is easy to become a point. Therefore, when a heavy object is placed on a luggage compartment or a bed provided at the rear part of the vehicle, the rear side member may be permanently deformed starting from the rigid breaking point depending on the load of the heavy object.

  In order to prevent the permanent deformation of the rear side member, it is conceivable to increase the plate thickness of the rear side member or to arrange a large-sized reinforcing member over the entire length of the rear side member in the longitudinal direction. Increase or decrease productivity.

  Then, one of the objectives of this invention is to provide the reinforcement structure of a rear side member which can suppress permanent deformation of a rear side member with a simple structure.

The reinforcement structure of the rear side member according to an aspect of the present invention is
Left and right rear side members extending in the vehicle front-rear direction,
Left and right cross member ends that are arranged so as to be bridged between the left and right rear side members and are joined to the left and right rear side members, respectively, and a cross member body that is located between the left and right cross member ends. A rear cross member having
A reinforcing member is provided which is joined to each of the left and right rear side members and is arranged such that a rear end surface located on the vehicle rear side is located on an extension line of the front surface of the cross member main body.

  When the reinforcing member is arranged in a part along the longitudinal direction of the rear side member, the rear side member has the original rigidity of the rear side member (hereinafter, referred to as low rigidity) at a position where the reinforcing member is not arranged, It has rigidity higher than low rigidity (hereinafter referred to as high rigidity) at the position where the member is arranged. The boundary portion between the portion where the reinforcing member is arranged and the portion where the reinforcing member is not arranged in the rear side member has a large difference in rigidity, and is likely to become a rigidity breaking point. In the reinforcing structure of the rear side member, the relative positional relationship between the rear cross member and the reinforcing member via the rear side member has a specific positional relationship, so that the difference in rigidity at the boundary portion can be reduced. Specifically, among the places where the rear side member has low rigidity, the place where the rear cross member is joined can have a rigidity between the low rigidity and the high rigidity, and the boundary portion has a rigidity higher than that of the conventional one. The rigidity can be changed in multiple steps or continuously changed. Since it is possible to reduce the difference in rigidity in the vicinity of the boundary between the portion where the reinforcing member is arranged and the portion where the reinforcing member is not arranged in the rear side member, it is possible to prevent the boundary portion from becoming a rigidity breaking point. Therefore, the reinforcement structure of the rear side member can suppress the permanent deformation of the rear side member at the boundary portion even when a heavy object is placed on the luggage compartment or the luggage carrier provided at the rear portion of the vehicle.

  In the reinforcing structure of the rear side member, the rear cross member and the reinforcing member are joined at a position where the difference in rigidity in the vicinity of the boundary between the place where the reinforcing member is arranged and the place where the reinforcing member is not arranged can be relaxed. The constituent members similar to the conventional ones can be used almost as they are. That is, it is not necessary to increase the plate thickness of the rear side member or use a large-sized reinforcing member. Therefore, the reinforcing structure of the rear side member is advantageous in terms of cost, weight, and productivity. Further, since the rear side member reinforcing structure does not use a large-sized reinforcing member, it is easy to control the buckling of the rear side member, and when a large load is applied from the rear of the vehicle due to a rear surface collision or the like, the load is applied to the rear side member. Can be properly absorbed by buckling.

It is the outline perspective view which looked at the reinforcement structure of the rear side member concerning an embodiment from the vehicle upper left diagonal side. It is a schematic perspective view which shows the disassembled state of the reinforcement structure of the rear side member which concerns on embodiment. It is explanatory drawing explaining the positional relationship of each structural member in the reinforcement structure of the rear side member which concerns on embodiment.

  A reinforcement structure for a rear side member according to an embodiment of the present invention will be described with reference to FIGS. 1 to 3. The same reference numerals in the drawings indicate the same names. In the following description, “front”, “rear”, “top”, “bottom”, “left”, “right” means the direction in which the front of the vehicle is “front” and this is the reference. In the figure, arrow FR is the front side in the vehicle front-rear direction, arrow RR is the rear side, arrow LH is the left side in the vehicle left-right direction (vehicle width direction), arrow RH is the right side, arrow UP is the upper side in the vehicle up-down direction, arrow LWR. Indicates the lower side.

〔overall structure〕
The reinforcement structure 1 for a rear side member according to the embodiment is configured in the vehicle rear portion. The vehicle rear part includes left and right rear side members 2 extending in the vehicle front-rear direction, a rear cross member 3 arranged so as to be bridged between the left and right rear side members 2, and a reinforcing member arranged in each of the left and right rear side members 2. 4 and. One of the features of the reinforcement structure 1 for a rear side member according to the embodiment is that the relative positional relationship between the rear cross member 3 and the reinforcing member 4 via the rear side member 2 has a specific positional relationship. Hereinafter, the configuration of the rear side member reinforcing structure 1 will be described first, and then the operation and effect will be described.

[Rear side member]
As shown in FIGS. 1 and 2, the rear side members 2 are arranged so as to extend in the vehicle front-rear direction on both outer sides in the vehicle width direction, and form a skeleton of the vehicle body. The left and right rear side members 2 have a substantially bilaterally symmetrical structure. The rear side member 2 supports a rear floor panel (not shown) that constitutes a floor of a luggage compartment or a luggage carrier provided at the rear of the vehicle.

  The rear side member 2 includes a bottom portion 21, a pair of side wall portions 22 extending from both sides of the bottom portion 21 to the vehicle upper side, and an upper flange portion 23 extending from the upper end of the side wall portion 22 to the opposite side of the side wall portions 22. And has a hat-shaped cross-section that opens to the upper side of the vehicle. The pair of side wall portions 22 are arranged substantially parallel to each other along the longitudinal direction of the rear side member 2. The rear end of the rear side member 2 is connected to a lower back panel 5 extending in the vehicle width direction. The rear side member 2 includes a lateral flange portion 24 extending from the rear end of the sidewall portion 22 to the opposite side of the sidewall portions 22 from each other, and the lateral flange portion 24 is joined to the front surface of the lower back panel 5. Examples of the joining method include welding and bolt fastening.

[Rear cross member]
As shown in FIGS. 1 and 2, the rear cross member 3 is located between the left and right cross member ends 3B joined to the left and right rear side members 2 and the cross member body located between the left and right cross member ends 3B. And a section 3A. The cross member main body portion 3A and the cross member end portion 3B are integrally molded and integrated.

  The cross member main body 3A includes a bottom portion 31, a pair of side wall portions 32 extending from both sides of the bottom portion 31 to the vehicle upper side, and an upper flange portion extending from the upper end of the side wall portion 32 to the opposite side of the side wall portions 32. 33, and has a hat-shaped cross section that opens toward the vehicle upper side. The pair of side wall portions 32 are arranged substantially parallel to each other along the longitudinal direction of the rear cross member 3. The cross member end portion 3B includes a lateral flange portion 34 extending from both longitudinal ends of the side wall portion 32 to the opposite side of the side wall portions 32, and a lower flange extending further longitudinally from both longitudinal ends of the bottom portion 31. And a part 35. As shown in FIG. 2, the lower flange portion 35 has a rectangular shape extending in the longitudinal direction of the bottom portion 31 and extending in a direction intersecting with the longitudinal direction of the bottom portion 31. The width of the rectangular lower flange portion 35 in the vehicle front-rear direction is larger than the width of the bottom portion 31 in the vehicle front-rear direction. In the rear cross member 3, the lateral flange portion 34 is joined to the side wall portion 22 on the inner side in the vehicle width direction of the rear side member 2, and the lower flange portion 35 is joined to the bottom portion 21 of the rear side member 2. Examples of the joining method include welding and bolt fastening. Welding includes fusion welding, pressure welding and brazing. Specific examples of the welding method include spot welding and quenching plug welding (SPW). In this example, each component is joined by SPW. In FIG. 1 and FIG. 3, the joints are indicated by crosses. The joint location and the number of joints can be appropriately selected.

(Reinforcing member)
As shown in FIGS. 1 and 2, the reinforcing member 4 is arranged on each of the left and right rear side members 2 and reinforces the rear side member 2. The reinforcing member 4 is arranged on a part of the rear side member 2 along the longitudinal direction. The reinforcing member 4 may have the same shape and size for the left and right rear side members, or may have different shapes and sizes for the left and right sides. In this example, the reinforcing members 4 having the same shape and size are used for the left and right rear side members 2.

  The reinforcing member 4 has a bottom portion 41 and a pair of side wall portions 42 that extend to the vehicle upper side from both sides of the bottom portion 41, and has a cross-section that is open to the vehicle upper side. The reinforcing member 4 is arranged in an internal space formed by the bottom portion 21 of the rear side member 2 and the pair of side wall portions 22. The reinforcing member 4 has a size such that the outer surfaces of the bottom portion 41 and the pair of side wall portions 42 are in contact with the inner surfaces of the bottom portion 21 and the pair of side wall portions 22 of the rear side member 2. In the reinforcing member 4, the bottom portion 41 is joined to the bottom portion 21 of the rear side member 2, and the pair of side wall portions 42 is joined to each of the pair of side wall portions 22 of the rear side member 2. Examples of the joining method include welding and bolt fastening. Welding includes fusion welding, pressure welding and brazing. Specific examples of the welding method include spot welding and quenching plug welding (SPW). In this example, each component is joined by SPW. In FIGS. 1 and 3, as with the rear cross member 3, the joints are indicated by crosses. The joint location and the number of joints can be appropriately selected.

  Here, the positional relationship between the rear side member 2, the rear cross member 3, and the reinforcing member 4 will be described with reference to FIG. FIG. 3 is a schematic view of the vicinity of a joint portion of the rear cross member 3 and the reinforcing member 4 with respect to the right side rear member 2 arranged on the right side in the vehicle width direction as seen from the vehicle upper side. The upper flange portion 23 and the upper flange portion 33 of the rear cross member 3 are omitted. As shown in FIG. 3, the reinforcing member 4 is arranged such that the rear end surface 43 located on the vehicle rear side is located on an extension line of the front surface 320 of the side wall portion 32 located on the vehicle front side of the cross member body 3A. To be done. That is, the reinforcing member 4 is arranged so as to be continuous with the cross member main body 3A without overlapping the cross member main body 3A of the rear cross member 3 when viewed in the vehicle front-rear direction. In this example, since the rear cross member 3 is provided with the lower flange portion 35 having a larger width than the bottom portion 31, when viewed from the vehicle upper side, a part of the lower flange portion 35 and the bottom portion 41 of the reinforcing member 4 overlap each other. It is arranged.

[Action and effect]
The reinforcing structure 1 for the rear side member is joined to the rear side member 2 so that the cross member body 3A of the rear cross member 3 and the reinforcing member 4 are continuous without overlapping when viewed in the vehicle front-rear direction. As a result, three levels of rigidity can be provided in the vicinity of the boundary between the portion where the reinforcing member 4 is arranged and the portion where the reinforcing member 4 is not arranged in the rear side member 2. Specifically, as shown in FIG. 3, the rear side member 2 has the original rigidity (low rigidity) of the rear side member 2 in a region C that is not joined to either the cross member body 3A or the reinforcing member 4. The joint area A with the reinforcing member 4 has a rigidity (high rigidity) higher than the low rigidity, and the joint area B with the cross member body 3A has a rigidity between the low rigidity and the high rigidity (medium). Rigidity). That is, near the boundary portion of the rear side member 2, it is possible to sequentially provide three stages of high rigidity, middle rigidity, and low rigidity from the front side of the vehicle toward the rear side. By providing the above-described three-stage rigidity in the vicinity of the boundary portion of the rear side member 2, it is possible to reduce the range of change in rigidity as compared with the case of two-stage rigidity of low rigidity and high rigidity. It is possible to prevent the boundary portion of the member 2 from becoming a rigid breaking point. Since the rigid side points are not formed on the rear side member 2, it is possible to suppress the permanent deformation of the rear side member 2 at the boundary portion even when a heavy object is placed on the luggage compartment or the luggage carrier provided at the rear portion of the vehicle. . In particular, since the rear cross member 3 and the reinforcing member 4 are joined to the rear side member 3 by welding, the rear side member 3 can suitably have the above three levels of rigidity.

  The present invention is not limited to these examples, but is defined by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope. For example, the following modifications are possible in the above-described embodiment.

  (1) In the lower flange portion 35 of the rear cross member 3, the front end surface located on the vehicle front side is on the extension line of the front surface 320 of the side wall portion 32 located on the vehicle front side, or on the vehicle rear side with respect to the extension line. It may be located. In this case, when viewed from the vehicle upper side, the lower flange portion 35 and the bottom portion 41 of the reinforcing member 4 are arranged without overlapping.

  (2) The lower flange portion 35 of the rear cross member 3 may be arranged over the entire region of the bottom portion 21 of the rear side member 2 in the vehicle width direction, or the side wall portion located further outside of the rear side member 2 in the vehicle width direction. It may be arranged over 32. By doing so, the rear side member 2 can be reinforced also by the lower flange portion 35. At this time, the thickness of the lower flange portion 35 is gradually reduced from the front side of the vehicle toward the rear side, whereby it is possible to provide the medium rigidity region with multiple stages of rigidity, and the boundary portion of the rear side member is provided. It is possible to provide rigidity in four or more stages in the vicinity. Further, the thickness of the lower flange portion 35 is gradually reduced from the vehicle front side to the rear side, so that the lower side of the rear side member 2 is continuously reduced from the vehicle front side to the rear side in the vicinity of the boundary portion. It is possible to have rigidity.

  (3) The thickness of the bottom portion 41 of the reinforcing member 4 can be gradually reduced from the front side of the vehicle toward the rear side. By doing so, the vicinity of the boundary portion of the rear side member 2 can be provided with a rigidity that continuously decreases from the vehicle front side toward the rear, and the difference in the rigidity of the boundary portion can be reduced. be able to.

  (4) The reinforcing member 4 may be arranged outside the rear side member 2. In this case, the reinforcing member 4 has a size such that the inner surfaces of the bottom portion 41 and the pair of side wall portions 42 are in contact with the outer surfaces of the bottom portion 21 and the pair of side wall portions 22 of the rear side member 2. When the reinforcing member 4 is arranged outside the rear side member 2 and the bottom portion 41 of the reinforcing member 4 is arranged so as to cover the lower flange portion 35, a portion of the bottom portion 41 of the reinforcing member 4 that overlaps with the lower flange portion 35 is disposed. It may be bent to form a step corresponding to the thickness of the lower flange portion 35. When the reinforcing member 4 is arranged outside the rear side member 2 and the lower flange portion 35 is arranged so as to cover the bottom portion 41 of the reinforcing member 4, the lower flange portion 35 overlaps the bottom portion 41 of the reinforcing member 4. The steps may be bent to form a step corresponding to the thickness of the bottom portion 41.

1 Reinforcement structure of rear side member 2 Rear side member 21 Bottom part 22 Side wall part 23 Upper flange part 24 Horizontal flange part 3 Rear cross member 3A Cross member main part 3B Cross member end part 31 Bottom part 32 Side wall part 320 Front face 33 Upper flange part 34 Horizontal flange Part 35 Lower flange part 4 Reinforcement member 41 Bottom part 42 Side wall part 43 Rear end face 5 Lower back panel

Claims (1)

Left and right rear side members extending in the vehicle front-rear direction,
Left and right cross member ends that are arranged so as to be bridged between the left and right rear side members and are joined to the left and right rear side members, respectively, and a cross member body that is located between the left and right cross member ends. A rear cross member having
A reinforcing member that is joined to each of the left and right rear side members and is arranged such that a rear end surface located on the vehicle rear side is located on an extension line of the front surface of the cross member main body portion ;
The left and right rear side members include a bottom portion and a pair of side wall portions that extend toward the vehicle upper side from both sides of the bottom portion, and have a shape that opens toward the vehicle upper side,
The reinforcing member includes a bottom portion that is in contact with the bottom portion and a pair of side wall portions that are in contact with each of the pair of side wall portions, and has a shape that opens toward the vehicle upper side and the vehicle rear side.
Reinforcement structure of the rear side member.

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