JP5149536B2 - Car body rear structure - Google Patents

Description

  The present invention relates to a vehicle body rear structure provided with a rear frame extending substantially along the vehicle longitudinal direction on both sides of the vehicle body.

  In many vehicles, a pair of rear frames are provided substantially along the vehicle front-rear direction under the rear floor, and the front end of the rear frame is coupled to a side sill that is a strength member at the center of the vehicle body. The rear frames are joined by a cross member. Each rear frame is normally formed in a substantially U-shaped cross section that opens upward, and the front side coupled to the side sill is formed at a low level, and the rear side is formed at a high level via a loose stepped portion. Has been. In other words, the lower region on the front side and the higher region on the rear side have a continuous shape with the bent region interposed therebetween.

By the way, in the rear vehicle body structure provided with such a rear frame, since a bending stress is likely to act on the bent region of the rear frame at the time of a rear collision, the lower region and the higher region of the rear frame straddle the bent region. A stiffener that is coupled linearly is provided (see, for example, Patent Document 1).

However, in this conventional vehicle body rear structure, the lower region and the higher region of the rear frame are connected by a stiffener, so that the rear collision load input to the rear portion of the rear frame is transmitted from the high region to the stiffener, It will be transmitted from the stiffener to the lower region, and it cannot be said that the collision load can be transmitted forward efficiently. That is, in this conventional vehicle body rear structure, since the two-stage joint is interposed in the load transmission path, efficient load transmission is hindered by the two-stage joint.
For this reason, in order to further increase the load transmission efficiency, it is necessary to increase the thickness of the rear frame or add a reinforcing member, and an increase in the weight of the vehicle body cannot be avoided.

  Therefore, the present invention is intended to provide a vehicle body rear structure capable of improving both the weight reduction and the rigidity improvement of the vehicle body by improving the load transmission efficiency of the rear frame in the substantially longitudinal direction of the vehicle body.

The invention according to claim 1, which solves the above-described problem, has a pair of rear frames (for example, rear frames 2A and 2B in the embodiments described later) that open upward on both sides of the vehicle body and have a substantially U-shaped cross section. Each of the rear frames has a low level region (for example, a low level region a in an embodiment described later) that extends substantially horizontally on the front side of the vehicle body and a high level region (for example, described later) that extends substantially horizontally on the rear side of the vehicle body. A rear region structure of the vehicle body comprising a high-order region b) in the embodiment and a bent region (for example, a bent region c in the embodiments described later) connecting the low-order region and the high-order region. To the bent region is formed by a first frame member (for example, a first frame member 20 in an embodiment to be described later) having a substantially U-shaped cross section that opens upward, and a high-level region of the rear frame. A substantially U-shaped cross section of the second frame member opening upward (e.g., the second frame member 21 in the embodiment) formed by the first frame member, the bend region to the rear end of the bending area A rear extension piece (for example, a rear extension piece 22 in an embodiment described later) that is continuous with the cross section of the rear extension piece is formed, and the upper surface of the rear extension piece is substantially straight with the upper surface of the lower region and the bent region. And a flange portion for panel bonding (for example, a flange portion 25 in an embodiment described later) is provided on the upper edge portion on both sides from the lower region to the bent region, and the second frame member is formed in the higher region. A front extension piece (e.g., a front extension piece 23 in an embodiment described later) extending forward is formed at the front end of the front end portion, and the front extension piece has the same depth as the higher region. Large at the root side of A surface portion (for example, a large cross-sectional portion 23a in an embodiment described later), a small cross-sectional portion (for example, a small cross-sectional portion 23b in an embodiment described later), which is shallower than the higher region, and the large cross-sectional portion A gradually changing cross-sectional portion (for example, a gradually changing cross-sectional portion 23c in an embodiment described later) whose depth gradually decreases from a small cross-sectional portion to a small cross-sectional portion, and a large cross-sectional portion and a gradually changing cross-sectional portion of the front extension piece And the bottom surface of the small cross section is formed by extending straight forward from the bottom surface of the high area, and a flange portion for panel bonding (for example, described later) on the upper edge of both sides of the high area and the large cross section. 26) in the embodiment is provided, the front edge of the second frame member is fitted inside the rear edge of the first frame member, and the first frame member and the second frame member are the rear extension pieces. And the front edge of the higher region between the bottom walls And a portion extending from the rear extension piece to the bent region and further to the rear edge portion of the lower region and extending from the front edge portion of the higher region of the second frame member to the front extension piece. The outer surface of the side wall is superposed and fixed along the longitudinal direction of the vehicle body.

Thus, the rear collision load input to the rear end portion of the rear frame is directly transmitted from the high region of the second frame member to the low region of the first frame member via the front extension piece . Further, the bent region of the first frame member is reinforced by the front extension piece that linearly extends from the higher region of the second frame member.

According to the invention described in claim 1, the rear frame is composed of a first frame member and second frame members, prior to the substantially U-shaped cross section that linearly extends forward from higher regions of the second frame member Since the bent region of the first frame member is efficiently reinforced along the substantially longitudinal direction of the vehicle body by the part extension piece, the rigidity of the vehicle body can be improved without causing an increase in weight due to an increase in the thickness of the rear frame. it can.
Further, according to the present invention, the first frame member is provided with the rear extension piece, and the bottom wall and both side walls of the rear extension piece are overlapped and fixed to the second frame member so as to enclose the outer surface. The bending rigidity of the frame can be reliably increased.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, unless otherwise specified, “up”, “down”, “front”, and “rear” mean up and down and front and rear of the vehicle 1 facing the forward direction. In the figure, an arrow F indicates the front of the vehicle 1, and an arrow U indicates the upper side of the vehicle 1.

  FIG. 1 is a view of a sedan-type vehicle 1 that adopts a vehicle body rear portion structure according to the present invention cut back and forth, and the rear portion of the cut vehicle 1 is viewed from obliquely upward, and FIG. FIGS. 3, 4, and 5 are enlarged cross-sectional views of the respective parts in FIG. 2, and FIG. 3, FIG. 4, and FIG.

  As shown in FIG. 1, a pair of rear frames 2A and 2B are arranged on the left and right sides below the rear portion of the vehicle 1 so as to extend substantially in the longitudinal direction of the vehicle body. Are coupled to each other by a middle cross member 3 and a rear cross member 4, and the front edge portions of both rear frames 2A and 2B are coupled to side sills 5A and 5B which are strength members on the side of the vehicle body. The left and right sides of the rear part of the vehicle body are provided with substantially arc-shaped rear wheel houses 6A and 6B covering the upper half of the outer periphery of the left and right rear wheels (not shown), and the lower edges of the rear wheel houses 6A and 6B. Are respectively coupled to the corresponding rear frames 2A and 2B.

  A rear parcel shelf 7 that partitions the vehicle compartment and the trunk room substantially vertically is provided at a rear side position of a rear seat (not shown). The rear parcel shelf 7 is provided with a parcel frame 8 having a substantially rectangular cross section extending in the vehicle width direction on the front end side, and both ends of the parcel frame 8 are arranged on the rear side via damper base covers 9 described later. While being supported by the wheel houses 6A and 6B, it is connected to a side panel inner 10 that forms an inner side wall of the vehicle body.

  The rear suspension 11 of the vehicle 1 uses a double wishbone type suspension that supports independent dampers 12 and springs 13 at different positions. In each of the left and right rear suspensions 11, the front end of the lower arm 14 is swingably supported by an arm support 15 on the inner side in the vehicle width direction of the rear cross member 4, and the upper end of the damper 12 is supported by the rear wheel houses 6A and 6B. The upper end of the spring 13 is attached to the spring support 17 on the lower surface of the rear frames 2A and 2B. The spring support portion 17 is provided in the vicinity of the coupling portion with the rear cross member 4 of the rear frames 2A and 2B.

  A wheel house frame 18 having a substantially U-shaped cross section extending in the vertical direction is joined to the side surfaces of the right and left rear wheel houses 6A and 6B at the side of the damper support portion 16, and the wheel house frames 18 are The ends are coupled to the end portions of the parcel frame 8 and the rear cross member 4. The parcel frame 8 and the rear cross member 4 thus form an annular skeleton frame together with the wheel house frames 18, 18 by connecting the end portions on both sides by the wheel house frames 18, 18. The parcel frame 8 is disposed at a position immediately above the rear cross member 4, and the entire annular skeleton frame is disposed in a plane perpendicular to the longitudinal direction of the vehicle body.

  The upper end portion of each wheel house frame 18 abuts on the lower surface of the edge of the parcel frame 8 in a substantially T shape and is coupled to the edge of the parcel frame 8. The damper base cover 9 that covers the upper portion of the damper support portion 16 at the top of the rear wheel houses 6A and 6B is provided below the edge of the parcel frame 8 that protrudes outward in the vehicle width direction from the wheel house frame 18. Has been placed.

  By the way, a spare tire pan (not shown) is connected to the upper surfaces of the left and right rear frames 2A and 2B and the rear cross member 4, and a spare tire (not shown) is attached to and detached from the rear cross member 4 on the spare tire pan. It can be attached as possible. A fuel tank (not shown) is arranged in the space between the rear cross member 4 and the middle cross member 3 below the spare tire pan.

  2 and 5, the left and right rear frames 2A and 2B extend substantially horizontally forward on the front side of the vehicle body and are connected to the side sills 5A and 5B and the middle cross member 3, respectively. a, a higher region b extending substantially horizontally to the rear side of the vehicle body at a position higher than the lower region a on the rear side of the vehicle body and coupled to the rear cross member 4, and inclined upward from the front side of the vehicle body toward the rear side And a bent region c connecting the lower region a and the higher region b.

  Here, each of the left and right rear frames 2A and 2B includes a first frame member 20 having a substantially U-shaped cross section that mainly forms a lower region a and a bent region c, and a substantially U-shaped cross section that mainly forms a higher region b. It is comprised with the 2nd frame member 21 of a shape.

  As shown in FIG. 5, the first frame member 20 is provided with a bent region constituting portion 20c having a bottom wall inclined upward toward the rear side of the vehicle body at the rear end portion of the lower region constituting portion 20a having a substantially constant depth. Further, a rear extension piece 22 is continuously provided at the rear end portion of the bent region constituting portion 20c. From the lower region constituting portion 20a to the rear extension piece 22, it is formed in a continuous substantially U-shaped cross section, but the upper edge on both sides from the lower region constituting portion 20a to the bent region constituting portion 20c is shown in FIG. As shown, a flange portion 25 for coupling a spare tire pan is provided. Note that the upper edge of the rear extension piece 22 is not formed with a flange 25 such as the lower region component 20a and the bent region component 20c, but the upper surface of the rear extension piece 22 is as shown in FIG. In addition, the lower region constituting portion 20 and the bent region constituting portion 20c are formed so as to be substantially straight.

  Further, as shown in FIG. 5, the second frame member 21 has a substantially U-shaped front portion extending forward from the high-level region constituting portion 21b at the front end portion of the high-level region constituting portion 21b having a substantially constant depth. The extension piece 23 (extension piece) is formed continuously. In the case of this embodiment, the front extension piece 23 includes a large cross-sectional portion 23a on the base portion side having the same depth as the high-order region constituting portion 21b, and a small cross-section on the tip portion side shallower than the high-order region constituting portion 21b. It is comprised from the part 23b and the gradually changing cross-sectional part 23c from which the depth becomes shallow gradually toward the small cross-sectional part 23b from the large cross-sectional part 23a. And although the depth of each cross section of the large cross-sectional portion 23a, the gradually changing cross-sectional portion 23c, and the small cross-sectional portion 23b of the front extension piece 23 changes, these bottom surfaces are straight forward from the bottom surface of the high-level region constituting portion 21b. Is formed. Moreover, as shown in FIG. 3, the flange part 26 for couple | bonding a spare tire pan is provided in the upper edge part of the both sides of the high region structure part 21b and the large cross-sectional part 23a.

  3 and 5, the front edge portion of the second frame member 21 is fitted inside the rear edge portion of the first frame member 20, and both are welded and fixed in a superposed state. . Specifically, the front edge portion of the high-level region constituting portion 21b of the second frame member 21 is welded and fixed in a superposed state inside the bottom wall and both side walls of the rear extension piece 22 of the first frame member 20, Both side walls of the front extension piece 23 of the second frame member 21 are welded and fixed inside the both side walls of the first frame member 20 in a superposed state. That is, in the first frame member 20 and the second frame member 21, the rear extension piece 22 and the front edge portion of the high-order region constituting portion 21b are overlapped and fixed at the bottom walls, and the bent region constituting portion 20c is formed from the rear extension piece 22. Further, the outer side wall surface of the portion extending from the front edge portion of the higher region constituting portion 21b of the second frame member 21 to the front extension piece 23 is disposed in the vehicle longitudinal direction on the side wall inner surface of the portion extending to the rear edge portion of the lower region constituting portion 20a. (See the region indicated by cross-hatching in FIG. 5).

  As described above, in the vehicle body rear structure of the vehicle 1, each of the rear frames 2 </ b> A and 2 </ b> B includes the first frame member 20 on the front side and the second frame member 21 on the rear side, and the second frame member. Since the front extension piece 23 having a substantially U-shaped cross section 21 is linearly crossed in the longitudinal direction of the vehicle body in the longitudinal direction of the vehicle body 20 in the first frame member 20, it is coupled to the lower region configuration portion 20a. The bent region component 20c can be efficiently reinforced by the front extension piece 23 of the member 21, and when a rear collision load is input to the rear ends of the rear frames 2A and 2B, the collision load is extended to the front. It can be transmitted directly to the lower region constituting part 20a of the first frame member 20 via the piece 23.

  Therefore, by adopting the rear structure of the vehicle body, the rigidity of the vehicle body, in particular, the rear frames 2A and 2B against the rear collision load is not caused without increasing the thickness of the rear frames 2A and 2B or adding a reinforcing member. The bending rigidity of can be reliably increased.

In the vehicle rear body structure of this embodiment, the rear extension piece 22 is provided on the first frame member 20, the second frame member 21 the bottom wall and both side walls of the rear extension piece 22 so as to enclose the outer surface Since it is superposed and fixed, this connecting portion structure is also advantageous in increasing the bending rigidity of the rear frames 2A and 2B.

  In addition, this invention is not limited to said embodiment, A various design change is possible in the range which does not deviate from the summary.

The one which showed one Embodiment of this invention, and looked at the vehicle body frame | skeleton part cut | disconnected forward and backward toward diagonally back side. The expansion perspective view of the rear frame of the vehicle body left side which shows the embodiment. Sectional drawing corresponding to the AA cross section of FIG. 2 which shows the same embodiment. Sectional drawing corresponding to the BB cross section of FIG. 2 which shows the same embodiment. Sectional drawing corresponding to CC cross section of FIG. 2 which shows the same embodiment.

Explanation of symbols

2A, 2B ... Rear frame 20 ... First frame member 20a ... Lower region component 20c ... Bent region component 21 ... Second frame member 21b ... Higher region component
22 ... Rear extension piece 23 ... Front extension piece
23a ... large cross section
23b ... small cross section
23c: Gradually changing cross section
25, 26 ... flange portions 25, 26
a ... Lower region b ... Higher region c ... Bent region

Claims (1)

A pair of rear frames having a substantially U-shaped cross-section opening upward on both sides of the vehicle body,
Each of the rear frames includes a low level region extending substantially horizontally on the vehicle body front side, a high level region extending substantially horizontally on the vehicle body rear side, and a bent region connecting the low level region and the high level region. A vehicle body rear structure,
A lower frame region to a bent region of the rear frame is formed by a first frame member having a substantially U-shaped cross section that opens upward, and a high-order region of the rear frame is a second that has a substantially U-shaped cross section that opens upward. Formed by frame members,
The first frame member forms a rear extension piece having a substantially U-shaped cross section continuous with a cross section of the bending area at a rear end of the bending area, and the upper surface of the rear extension piece is divided into a lower region and an upper surface of the bending area. It is formed so as to form a substantially straight line, and a flange portion for panel bonding is provided on the upper edge of both sides from the lower region to the bent region,
The second frame member forms a front extension piece having a substantially U-shaped cross section extending forward at a front end portion of a high region,
The front extension piece has a large cross section on the root side that is the same depth as the high region, a small cross section on the tip side that is shallower than the high region, and the large cross section toward the small cross section. And a gradually changing cross-sectional portion where the depth gradually decreases,
The front extension piece has a large cross-sectional portion, a gradually changing cross-sectional portion, and a bottom surface of the small cross-sectional portion that extends straight from the bottom surface of the high-level region to the front, A flange for panel bonding is provided at the edge,
Fitting the front edge of the second frame member inside the rear edge of the first frame member;
The first frame member and the second frame member overlap and fix the rear extension piece and the front edge portion of the higher region at the bottom walls, and from the rear extension piece to the bent region and further to the rear edge portion of the lower region. A rear structure of a vehicle body, characterized in that an outer surface of a side wall of a portion extending from the front edge portion of the higher region of the second frame member to the front extension piece is overlapped and fixed along the vehicle longitudinal direction on the inner surface of the side wall of the second portion.

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