car rear body structure

Abstract

A rear body structure of an automobile, comprising: a rear sub-frame (21), comprising left and right longitudinal beams (22) and a cross beam (23) connecting the two longitudinal beams (22); Subframe (21) is supported. The beam portion (23) has left and right side portions (23S) made of tubular members extending inward and downward in the vehicle width direction from the left and right side beam portions (22), respectively, and tubular members (23S) connecting the side portions (23S) on both sides. The central part (23C) composed of components. The height of the central portion (23C) is set lower than the central position of the upper arm support portion (28) and the lower arm support portion (29) in the vertical direction.

Description

technical field [0001] The present invention relates to a rear body structure of an automobile provided with a rear subframe including left and right side beams and a cross beam connecting the two side beams, and a rear suspension composed of the Rear subframe support. Background technique [0002] In general, a rear subframe (synonymous with a rear suspension beam) supporting a rear suspension includes left and right side beams and a beam connecting the two side beams. As a rear body structure of an automobile having such a rear subframe, known Figure 16 , Figure 17 structure shown. [0003] Schematically represented in bottom view on Figure 16 In the conventional structure (Patent Document 1), a subframe 80 including left and right side beams 81, 81 and front and rear cross beams 82, 83 is provided, and fixing portions 81a on the front and rear sides of each side beam 81, 81 are provided. , 81b are respectively connected to the left and right rear side members 84, 84...

AI Technical Summary

Problems solved by technology

[0007] That is, since the distance between the fixing parts 81a and 81b at the front and rear of the longitudinal beam 81 is long and curved, the thickness of the longitudinal beam 81 must be increased in order to ensure rigidity against the input of lateral force, resulting in an increase in weight.

[0008] Moreover, when a rear collision occurs, the rear collision load on the rear portion of the rear side member 84 is as follows: Figure 16 As indicated by the arrows in , it is concentrated on the front part of the rear side sill 84, so there is a problem that the amount of deformation of the surrounding parts of the side sill located in front of the rear side sill 84 increases.

[0009] In addition, the distance between the front fixing portion 81a and the support portion 88a of the front lower arm 88 is long, which is disadvantageous in terms of rigidity.

[0010] In addition, although the front portion 81c of the side member 81 is connected to the cross member 85 by the extension member 86, the rigidity of the subframe 80 is increased to some extent, but if the length of the extension member 86 is long, the following Problem: The extension member 86 is easily deformed, and the installation space of the extension member 86 is required, and the weight increases

which is, Figure 17 In the conventional structure shown, the beam portion 82 is made of a plate, and the amount of vertical offset between the support portion 88a of the lower arm 88 on the front side and the central portion of the beam portion 82 is large, so it is not possible to sufficiently ensure the response to out-of-phase. The rigidity of the lateral force, and there is a problem that the plate beam part 82 has a problem of surface resonance around the frequency of 300 Hz

[0017] Thus, conventionally, in the rear body structure of an automobile, sufficient consideration has not been given to ensuring rigidity against in-phase lateral force and out-of-phase lateral force and suppressing surface resonance.

Images