JP2006137272A - Rear body structure for automobile - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rear body structure for an automobile, capable of achieving economy with relation to weight and cost, and improving rigidity to lateral load of a rear suspension tower without limiting lateral width of a cabin floor, so as to improve torsional rigidity to torsion of a car body. <P>SOLUTION: This rear body structure for an automobile is provided with a right and a left rear floor side members 4 extended in the longitudinal direction, a right and a left rear suspension towers 1 respectively jointed with outside parts of the rear floor side members 4, and a cross member 5 stretched along the car width direction between the right and the left rear floor side members 4 at a corresponding position to the rear suspension towers 1. A lower end of the rear suspension tower 1 is extended downward of the rear floor side member 4, and an extended end 11 is connected to the cross member 5 by a brace 6 extended in the car width direction. Rigidity of the rear suspension tower 1 against falling deformation is thus increased. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rear structure of an automobile body, and more particularly to a structure around a joint portion between left and right rear floor side members and a rear suspension tower.

  As shown in FIG. 4, conventionally, a rear suspension tower 1 </ b> A at the rear of a vehicle body of an automobile is integrally formed with the rear wheel house 2, and the lower end of the tower is along the lower surface of the side edge of the floor panel 3 of the passenger compartment. It is coupled to the outer side of the rear floor side member 4 that extends in the longitudinal direction of the vehicle body. The rear suspension tower 1A is provided symmetrically at both left and right positions of the rear part of the vehicle body, and cross members 5 extending in the vehicle width direction along the lower surface of the floor panel 3 are disposed at positions corresponding to the left and right rear suspension towers 1A. It is installed between the left and right rear floor side members 4 (FIG. 4 shows only the peripheral structure of the rear suspension tower 1A on one side).

  By the way, the upper end of the rear suspension shock absorber 90 is connected to the tower top of the rear suspension tower 1A, and a lateral load from the shock absorber 90 in the lateral direction is applied to the tower top when the vehicle suddenly turns or runs on a rough road. (Arrow X) acts. When a lateral load X acts on the top of the tower, the rear suspension tower 1A as a whole falls and deforms inward in the vehicle width direction or outside of the vehicle with the connecting portion with the rear floor side member 4 at the lower end as a fulcrum. In this case, as shown in FIG. 5, for example, when the left and right rear suspension towers 1A are tilted in the direction of the arrow X ′, the rear body LB composed of the floor panel 3, the left and right rear floor side members 4 and the cross member 5 is The upper body UB of the vehicle body on the upper side of the suspension tower 1A falls in the same direction (arrow Y) as that of the rear suspension tower 1A, and the vehicle body is twisted. In FIG. 5, torsional deformation is exaggerated in order to explain the twisting mode. As described above, the rigidity of the rear suspension tower 1A with respect to the lateral load greatly affects the torsion of the vehicle body, and this tendency is particularly great in a one-box vehicle having a high vehicle height.

  Therefore, as a conventional structure that strengthens the rigidity of the rear suspension tower against a lateral load, as disclosed in Patent Document 1 below, a gusset that supports the rear suspension tower is provided on the floor of the passenger compartment, and the rear suspension tower collapses. Deformation is being suppressed. In this case, the width of the passenger compartment floor is restricted by the gusset and becomes narrow, so that it is not suitable for a one-box vehicle equipped with a third seat.

  Further, there is one disclosed in Patent Document 2 below as a conventional reinforcing structure that does not restrict the width of the passenger compartment floor. As shown in FIG. 6, an extension 15 is formed at the lower end of the rear suspension tower 1 </ b> B that projects downward from the rear floor side member 4, while the cross extends in the vehicle width direction along the lower surface of the floor panel 3. At the end of the member 5A, a reinforcing portion 51 having a diameter expanded so as to protrude downward from the rear floor side member 4 is formed. The extending portion 15 of the rear suspension tower 1B and the reinforcing portion 51 of the large-diameter cross member 5A are formed. Are coupled to the end edges of the rear suspension tower 1B to enhance the rigidity against the lateral load of the rear suspension tower 1B.

  However, in the conventional structure of Patent Document 2, the cross member 5A is large, and the weight of the vehicle body and the production cost are greatly increased, which is uneconomical. In particular, when it is necessary to increase the thickness of the reinforcing portion 51 in order to improve the strength, it is necessary to increase the thickness of the entire cross member 5A, which further increases weight and cost.

Further, since the vertical surface of the extension portion 15 of the rear suspension tower 1B extending downward and the flange at the edge of the reinforcement portion 51 of the cross member 5A are superposed in the vehicle width direction, the joint portion between them is The separation direction with respect to the load is not sufficient for the lateral load of the rear suspension tower 1B.
Japanese Utility Model Publication No. 62-13785 Japanese Utility Model Publication No. 5-139342

  Therefore, in view of the above circumstances, the present invention is economical in terms of weight and cost, and can efficiently and reliably enhance the rigidity of the rear suspension tower against the lateral load without restricting the lateral width of the passenger compartment floor. It is an object to realize a rear structure of an automobile body with high torsional rigidity.

  The present invention relates to left and right rear floor side members extending in the front-rear direction, left and right rear suspension towers respectively joined to outer portions of the rear floor side members, and the left and right rear floor sides at positions corresponding to the left and right rear suspension towers. In a rear structure of an automobile body provided with a cross member that extends between members in the vehicle width direction, the lower end of the rear suspension tower extends below the rear floor side member, and the extended end and the cross member Are connected by braces extending in the vehicle width direction (claim 1). When a lateral load acts on the top of the tower of the rear suspension tower, the rear suspension tower will fall and deform with the joint with the rear floor side member as a fulcrum, and the extended end of the lower end will move in the opposite direction to the movement of the tower top. However, since the movement of the extending end is restricted by the brace, the entire rear suspension tower is prevented from falling. Further, since the cross member and the extended end of the rear suspension tower are connected by the brace, it is not necessary to increase the size of the cross member as in the conventional structure, which is economical in terms of weight and cost.

  The extending end of the rear suspension tower is provided with a horizontal portion that bends inwardly of the vehicle body, while the brace is formed of a plate body, and one end is overlapped with the lower surface of the cross member and joined from the connecting portion. The vehicle body extends outwardly and downward in an inclined manner, and the other end is overlapped and joined to the lower surface of the horizontal portion of the extended end of the rear suspension tower. The joint part between the brace and the extended end of the rear suspension tower and the joint part between the brace and the cross member have a joint structure in a shearing direction with respect to the lateral load, and the joint strength of the joint part with respect to the lateral load is high. The rigidity against the tower falling deformation is improved.

  The connection between one end of the brace and the lower surface of the cross member and the connection between the other end of the brace and the horizontal portion of the extended end are respectively bolted together (Claim 3). In the vehicle manufacturing process, the upper body consisting of the roof, side, wheel house, and rear suspension tower of the vehicle body, and the lower body consisting of the passenger compartment floor, rear floor side member, cross member, etc. are assembled separately. Later, the upper body and the lower body were joined, and it took a lot of work to weld the members straddling the upper body and the lower body like the brace, but the brace was bolted so that the brace was joined. The mounting workability is good.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view taken along line II of FIG. 2, showing a main part of an embodiment to which the present invention is applied. FIG. 2 is a plan view of the main part of the present embodiment as viewed from the bottom of the vehicle body floor. 3 is a perspective view of the under floor area of the rear part of the vehicle body as viewed obliquely from below. As shown in FIG. 3, rear wheel houses 2 and 2 are formed on the left and right side positions around the under floor of the rear part of the vehicle body, and the lower surface of the floor panel 3 of the passenger compartment is between the left and right rear wheel houses 2 and 2. A pair of left and right rear floor side members 4, 4 extending in the longitudinal direction of the vehicle body are provided along the left and right side edges of the left and right sides, and between the left and right rear floor side members 4, 4 along the lower surface of the floor panel 3 in the vehicle width direction. A plurality of extending cross member members 5, 5, and 5 are installed. The left and right rear floor side members 4 and 4 are arranged so that the distance between the two rear floor side members 4 and 4 is narrow at a position facing both the rear wheel houses 2 and 2 so as to avoid the left and right rear wheel houses 2 and 2. However, at the rear position of the rear wheel house 2, it is bent and displaced in a Z-shape toward the outside of the vehicle so as to avoid the fuel tank 7 provided on the lower surface of the rear end of the passenger compartment floor. The interval is enlarged.

  The structure around the left and right rear wheel houses 2 and 2 is bilaterally symmetric, and the structure around one wheel house 2 will be described below. As shown in FIG. 1, the rear wheel house 2 includes a vertical wall-shaped inner panel 21 whose upper end is curved outwardly of the vehicle body, and a quarter panel 8 that forms the upper edge of the inner panel 21 and the outer surface of the vehicle body. The outer panel 22 extends between the lower edge and the lower end of the inner panel 21 is coupled to the outer side of the rear floor side member 4.

  The rear floor side member 4 has a substantially U-shaped cross section that opens toward the outside of the vehicle body, and includes an upper wall portion and an upper edge flange that is bent upward from its end edge, and a lower surface of the side edge portion of the floor panel 3 and It overlaps and is joined to the floor flange bent upward from the side edge. In connection with the inner panel 21, the lower edge flange provided at the edge of the lower wall portion of the rear floor side member 4 is overlapped and welded to the inner side of the lower panel of the inner panel 21, and the upper edge flange is connected to the floor panel. 3 and the side edge flanges are overlapped and welded to the intermediate position of the lower end of the inner panel 21. The rear floor side member 4 forms a closed section with the inner panel 21 of the rear wheel house 2.

  The cross member 5 laid between the left and right rear floor side members 4 has a substantially inverted hat cross section, and a pair of upper edge flanges are overlapped on the lower surface of the floor panel 3 and welded to form a closed cross section with the floor panel 3. The end of the cross member 5 is welded with the side edge flange overlapped with the vehicle body inner surface of the vertical wall portion of the rear floor side member 4 and the lower edge flange overlapped with the lower surface of the lower wall portion of the rear floor side member 4. Welded.

  The rear suspension tower 1 is formed at a position behind the rear wheel house 2 and has a double structure in which the tower brackets 10 are overlapped along the inner surface of the inner panel 21. The tower bracket 10 is made of a metal plate, and the upper end portion has a substantially semi-cylindrical shape that opens downward and outward of the vehicle body, and the upper surface portion is integrally formed with the upper end portion of the inner panel 21 and the upper end of the shock absorber (not shown). They are connected to support this.

  An intermediate portion of the tower bracket 10 is overlapped with a lower end portion of the inner panel 21, and is coupled to an upper edge flange and a lower edge flange of the rear floor side member 4 integrally with the lower end portion of the inner panel 21. At the lower end of the tower bracket 10, an extending end 11 having a vertical wall shape extending downward from the rear floor side member 4 is formed. A horizontal portion 12 is formed at the lower edge of the extended end 11 and is bent at a substantially right angle toward the inside of the vehicle body over the entire length thereof.

  The lower end of the extending end 11 of the tower bracket 10 and the cross member 5 are connected by a brace 6. The brace 6 is formed by bending a flat metal plate with a plate body that bridges the lower surface of the end portion of the cross member 5 and the lower end of the extending end 11 of the rear suspension tower 1 along the vehicle width direction. One end 61 of the brace 6 has a width dimension matching the front and rear width dimensions of the lower surface of the cross member 5, and a horizontal attachment portion having a plurality of bolt through holes is formed in the longitudinal direction. The brace 6 has a gentle oblique downward inclination from one end 61 to the other end 62, and the width dimension gradually increases from the one end 61 to the other end 62. The other end 62 has a width dimension that matches the width dimension before and after the horizontal portion 12 at the lower end of the extended end 11 of the rear suspension tower 1, and the other end 62 has a plurality of bolt through holes. Is a horizontal mounting portion facing the horizontal portion 12. Further, the brace 6 is reinforced by forming a flange that bends downward along side edges on both sides along the longitudinal direction.

  The brace 6 has one end 61 overlapped with the lower surface of the end of the cross member 5 and a plurality of bolts B penetrating the bolt through holes are coupled to screw holes having weld nuts provided on the lower surface of the end of the cross member 5. The other end 62 is superposed on the horizontal portion 12 of the extending end 11 of the rear suspension tower 1 from below, and the plurality of bolts B are used in the same manner as the one end 61. It is connected.

  When a lateral load in the vehicle width direction acts on the upper end of the rear suspension tower 1 when the vehicle is turning sharply or traveling on a rough road, the rear suspension tower 1 falls laterally around the joint with the rear floor side member 4 as a fulcrum. The extended end 11 lower than the coupling portion tries to move in a direction opposite to the moving direction of the tower upper end portion. According to this embodiment, since the lower end of the extended end 11 of the rear suspension tower 1 is connected to the cross member 5 by the brace 6, the brace 6 can be supported and the movement of the extended end 11 can be prevented. As a result, the entire lateral suspension tower 1 can be prevented from collapsing in the lateral direction, and the rigidity of the rear suspension tower 1 against the deformation can be enhanced. Further, by strengthening the rigidity of the rear suspension tower 1 against the falling deformation, the vehicle body upper structure is suppressed, and the rear structure of the vehicle body having high torsional rigidity against the torsion of the vehicle body is obtained.

  Further, the brace 6 has a connecting portion between the one end 61 and the cross member 5 and a connecting portion between the other end 62 and the extending end 11 of the rear suspension tower 1 with respect to the movement (lateral load) of the extending end 11. Thus, the coupling force is high, and the rigidity against the falling deformation of the rear suspension tower 1 can be further enhanced.

  Since the brace 6 is provided under the floor of the vehicle body, the lateral width on the passenger compartment floor is not restricted, and the brace 6 is configured with a simple structure and a small metal plate, which is economical in terms of weight and cost.

  The brace 6 is attached so as to connect the cross member 5 and the extended end 11 of the rear suspension tower 1 after connecting the upper body and the lower body of the vehicle body in the manufacturing process of the vehicle body. Since the connecting portion between the other end 62 and the extending end 11 of the rear suspension tower 1 is connected with the bolt B, the attachment workability is good. However, the present invention is not limited to this, and from the viewpoint of strengthening the joint strength between the two joint portions, the attachment work takes some time, but both joint portions may be welded.

FIG. 3 is a cross-sectional view taken along the line II of FIG. 2, showing a main part of a vehicle body rear structure to which the present invention is applied. It is the top view which looked at the principal part of the above-mentioned body rear part structure from the body floor under. It is the perspective view which looked at the said vehicle body rear part structure under the floor from diagonally downward. FIG. 2 is a cross-sectional view of a main part of a conventional vehicle body rear structure corresponding to FIG. 1. It is explanatory drawing which shows the aspect of the twist of a vehicle body. FIG. 5 is a cross-sectional view of a main part of another conventional rear body structure corresponding to FIG. 4.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rear suspension tower 10 Tower bracket 11 Extension end 12 Horizontal part 2 Rear wheel house 3 Floor panel 4 Rear floor side member 5 Cross member 6 Brace 61 One end 62 Other end B Bolt member

Claims (3)

The left and right rear floor side members extending in the front-rear direction, the left and right rear suspension towers joined to the outer sides of the rear floor side members, and the left and right rear floor side members at positions corresponding to the left and right rear suspension towers In the rear structure of an automobile body with a cross member extending in the width direction,
A rear structure of an automobile body, wherein a lower end of the rear suspension tower extends below the rear floor side member, and the extended end and the cross member are connected by a brace extending in a vehicle width direction. While the extending end of the rear suspension tower is provided with a horizontal portion bent inward of the vehicle body,
The brace is composed of a plate, and one end is overlapped and coupled to the lower surface of the cross member, and extends obliquely outward and downward from the coupling portion, and the other end extends to the rear suspension tower. 2. The rear structure of an automobile body according to claim 1, wherein the rear structure of the automobile body is overlapped and joined to the lower surface of the horizontal portion at the end.   The rear part of an automobile body according to claim 1 or 2, wherein the connection between one end of the brace and the lower surface of the cross member and the connection between the other end of the brace and the horizontal part of the extended end are respectively bolted. Construction.

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