JP2014213709A - Front part vehicle body structure of automobile - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a front part vehicle body structure of an automobile, capable of enhancing support rigidity of wheels by efficiently distributing vehicle width direction component force to a suspension member and a brace to impose the component force on them.SOLUTION: A suspension side bent part 11b having an upward concave shape is formed in a vehicle width direction central part of a suspension member (a rear side member body) 11, a brace member 12 extending in the vehicle width direction is connected to both end parts of the suspension side bent part 11b such that the brace member 12 bridges the suspension side bent part 11b, a portion of the brace member 12 facing to the suspension side bent part 11b is formed with a brace side bent part 12b having a downward concave shape, and central parts d of support bushes 4e provided in base end parts 4c' of lower arms 4 are nearly brought into line with a centroid G position of both cross sections of the suspension side bent part 11b and the brace side bent part 12b.

Description

  The present invention relates to a left and right side member, a suspension member suspended below the both side members, and a lower arm supported by the suspension member so as to be swingable up and down and supporting a front wheel. It relates to the front body structure.

  Conventionally, for example, Patent Documents 1 and 2 disclose a front body structure of an automobile in which a suspension member that supports a lower arm so as to swing up and down is provided below left and right side members. In the conventional structure disclosed in Patent Document 1, a bent portion that is recessed upward is formed on the lower surface of the central portion in the vehicle width direction of the suspension member, and both ends of the suspension member are bolted and fixed to the side members. The base end of the lower arm is supported so that it can swing up and down.

Further, in Patent Document 2, a suspension member is suspended from a lower surface of a side member with a bracket interposed therebetween, and a bent portion having a concave shape is formed at an intermediate portion in the vehicle width direction of the suspension member. In addition, braces that extend substantially linearly in the vehicle width direction are connected to both ends of the bent portion of the suspension member.

Actual opening and closing 4-1006 Japanese Patent No. 4124334

  In general, in the suspension member, a vehicle width direction component force input in the front-rear direction acting on the wheel supported by the lower arm acts on the suspension member from the attachment point of the lower arm to the suspension member. In the conventional suspension member disclosed in Patent Document 1, since the bent portion that is recessed upward is formed on the lower surface of the suspension member, the bent portion of the suspension member is generated by the component force in the vehicle width direction that is input from the lower arm. Since a relatively large bending moment is generated, there is a problem that it is difficult to ensure the wheel support rigidity.

Further, in Patent Document 2, although the bent portion of the suspension member is bridged by a brace, the brace is substantially straight, so that the component force in the vehicle width direction is efficiently distributed to the suspension member and the brace. It cannot be made to bear. Therefore, a bending moment is generated at the bent portion of the suspension member. Further, since the suspension member is separated downward from the side member functioning as a rigid body, the bending moment also increases from this point, and eventually the wheel support rigidity cannot be improved so much while adding the brace.

The present invention has been made in view of the above-described conventional situation, and it is possible to increase the supporting rigidity of a wheel by distributing the vehicle width direction component force to a suspension member and a brace and causing the load to be increased. The challenge is to provide a structure.

According to the first aspect of the present invention, there are provided left and right side members that are disposed on both sides in the vehicle width direction and extend in the vehicle front-rear direction, suspension members that are suspended below the side members, and the suspension members In the front body structure of an automobile provided with a lower arm whose base end is supported so as to be swingable up and down,
A suspension-side bent portion having a concave shape is formed in the vehicle width direction central portion of the suspension member, and brace members extending in the vehicle width direction are connected to both ends of the suspension-side bent portion of the suspension member. The bent portion is connected so as to bridge, and a brace-side bent portion that is concave downward is formed at a portion of the brace member facing the suspension-side bent portion of the suspension member, and the base end of the lower arm is formed The center part of the support bush provided in the part is made to substantially coincide with the centroid position of the suspension side bent part and the brace side bent part.

According to a second aspect of the present invention, in the front body structure of the automobile according to the first aspect,
The suspension-side bent portion and the brace-side bent portion are connected by a body part support bracket.

  According to the present invention, the suspension member is joined so that both ends of the suspension-side bent portion formed so as to form a concave shape upward are bridged by the brace-side bent portion formed so as to form a concave shape downward. In addition, since the centroid of the cross section of both bent portions and the central portion of the support bush at the base end portion of the lower arm are positioned at substantially the same height, a load from the base end portion of the lower arm toward the vehicle width direction is applied. The suspension member and the brace can be input toward the schematic centroid, and therefore the vehicle width direction load can be distributed by being evenly distributed between the suspension member and the brace member. Further, since the offset amount with respect to the input of the centroids of the two members is small, the bending moment due to the centroid offset generated in the two members can be reduced, and as a result, the support rigidity of the front wheel can be improved.

Further, since the support rigidity of the front wheel can be increased, the characteristics of the elastic member of the support bush at the base end portion of the lower arm can be effectively exhibited, and both high steering stability and riding comfort can be achieved.

In addition, since a relatively large space is formed between the suspension-side bent portion and the brace-side bent portion, the degree of freedom in layout of vehicle parts such as a drive system can be improved using the space.

According to the second aspect of the present invention, since the suspension-side bent portion and the brace-side bent portion are coupled by the vehicle body component support bracket, the rigidity of the suspension member can be increased and the steering stability can be improved. In addition, when the drive system unit is coupled to a rigid suspension member, it is possible to prevent the vibration of the drive system from being transmitted from the floor panel to the vehicle interior as when the support bracket of the drive system unit is fixed to the floor. Vibration, noise performance can be improved.

1 is a plan view of a front body structure of an automobile according to Embodiment 1 of the present invention. It is a rear view of the front body structure. It is a left view of the front body structure. FIG. 4 is a cross-sectional side view of the front body structure (a cross-sectional view taken along line IV-IV in FIG. 2).

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 4 are views for explaining a front body structure of an automobile according to Embodiment 1 of the present invention. In this embodiment, front, rear, left, and right refer to the front of the vehicle from the vehicle interior. This means front, back, left, and right as viewed.

In the figure, a front vehicle body 1 according to the first embodiment is disposed on both sides in the vehicle width direction and extends in the vehicle front-rear direction, and the left and right side members 2 and 2 are suspended below the side members 2 and 2. The suspension member 3 is constructed so as to be lowered, and the lower arm 4 is supported by the suspension member 3 so as to be swingable up and down.

The left and right side members 2 and 2 have a hat shape opened upward having a vertical wall portion 2a, a bottom wall portion 2b, and a flange portion 2c bent at the upper edge in a cross-sectional view, A floor panel 7 is fixed on the flange portion 2c.

The suspension member 3 includes a front member 5 and a rear member 6, and the left and right side portions are respectively spaced downward from the side member 2 via front brackets 8 and rear brackets 9. It is erected to bridge members 2 and 2.

The front member 5 extends in a substantially straight line shape in the vehicle width direction, and has a rectangular tube shape in which the left and right end portions 5a and 5a are opened. The left and right end portions 5a and 5a are fixed to the leg portion 8a of the front bracket 8, and a flange portion 8b provided at the upper end of the leg portion 8a is fastened and fixed to the bottom wall 2b of the side member 2 by bolts 10a. ing.

A front bush 4b fixed to the base end portion of the front arm portion 4a of the lower arm 4 is inserted and disposed in the opening of the left and right end portions 5a of the front member 5. The front bush 4b is a cylindrical bush formed by baking and fixing an elastic member such as rubber between the inner and outer cylinders, and the central axis a thereof is arranged in the vehicle front-rear direction and slightly forward and downward. , Are attached to the right end portion 5a so as to be swingable up and down.

The lower arm 4 is formed in a substantially L shape with the front arm portion 4a and a rear arm portion 4c extending obliquely inwardly from the rear of the vehicle, and a support projecting outward in the vehicle width direction from the L-shaped corner portion. The front wheel 20 is attached to the part 4d via a knuckle arm (not shown).

A rear bush 4e is fixed to the base end 4c 'of the rear arm 4c of the lower arm 4, and the rear bush 4e is formed by baking and fixing an elastic member such as rubber between the inner and outer cylinders. The axis b is inserted into an opening 11b of the left and right end portions 11a, which will be described later, of the rear member 6 with the longitudinal direction extending slightly upward and obliquely upward, and is attached so as to be swingable up and down by a bolt 10e. .

The rear member 6 includes a rear member main body 11 and a brace member 12. The rear member body 11 has a suspension-side bent portion 11b that extends in the vehicle width direction and is bent so as to form a concave shape upward from the left and right end portions 11a and 11a. The rear member main body 11 is arranged so as to bridge over the lower surfaces of the left and right rear brackets 9 and 9 fixed to the bottoms of the left and right side members 2 and 2, and Upper flange portions 11a ′ of the portions 11a and 11a are fastened and fixed to the flange portions 9a of the rear brackets 9 and 9 by bolts 10c.

The rear member body 11 includes a hat-shaped lower member 11c that opens upward in a cross-sectional view, and a lid member 11d that is fixed so as to close the upper opening of the lower member 11c. The left and right end portions 11a are greatly enlarged in the front-rear direction and the vertical direction so that the rear bush 4e can be disposed, and the base end portion 4c 'of the rear arm portion 4c of the lower arm 4 swings up and down. And an opening 11e having a size that does not interfere with each other. The enlarged flange portions 11a 'of the left and right end portions 11a are fastened and fixed to the flange portion 9a of the rear bracket 9 by bolts 10c.

The brace member 12 is formed with a brace-side bent portion 12b having a downward concave shape that is substantially symmetrical with the suspension-side bent portion 11b of the rear member main body 11, and the bent portions 12b and 11b. A larger space C is formed.

The brace member 12 includes a hat-shaped upper member 12c that opens downward in a cross-sectional view, and a lid member 12d that is fixed so as to close the lower opening of the upper member 12c. The left and right end portions 12a, 12a of the upper member 12c are fixed by welding to the inclined portions constituting the bent portion 11b of the lower member 11c of the rear member body 11. An opening c for the welding operation is formed between the left and right ends of the lid member 12d of the brace member 12 and the lower member 11c of the rear member body 11. A welding machine torch or the like is inserted from the opening c to weld the connecting point A portion between the upper member 12c and the lower member 11c.

Here, the connection point A between the rear member main body 11 and the brace member 12 is at a height position substantially coincident with a straight line B connecting the axial center points d and d of the left and right rear bushes 4e and 4e. Is set. Here, the axial center point d of the rear bush 4e is substantially coincident with the position of the centroid G (see FIG. 4) in the cross section of both the suspension side bent portion 11b and the brace side bent portion 12b. It is arranged. Note that only the height position of the centroid G is displayed in FIG.

The lower member 11 c of the rear member main body 11 and the upper member 12 c of the brace member 12 are coupled by a support bracket 13. The support bracket 13 has a U shape in a plan view in cross section, and supports the mount member 15 of the front wheel differential mechanism 14.

The mount member 15 comprises a cylindrical bush formed by baking an elastic member between the inner and outer cylinders, and is fixed to the support bracket 13 by a bolt 10d inserted substantially horizontally in the vehicle width direction. A mount bracket 15 a fixed to the mount member 15 is fixed to the differential mechanism 14. A propeller shaft 16 connected to the differential mechanism 14 via a universal joint 16 a is mounted on the rear side of the rear member 6 through a space C between the rear member body 11 and the brace member 12. Connected to an engine unit (not shown).

  According to the present embodiment, the suspension-side bent portion 11b is formed in the rear member body 11 of the rear member 6 constituting the rear portion of the suspension member 3 so as to form a concave shape upward, and the suspension-side bent portion. The left and right end portions 11a and 11a of 11b are connected so as to bridge the left and right end portions 12a and 12a of the brace-side bent portion 12b formed so as to form a concave shape below the brace member 12, and the both The connection point A of the bent portions 11b and 12b is positioned at substantially the same height as the straight line B connecting the center portions d and d of the rear bush 4e provided at the base end portion 4c ′ of the lower arm 4. The central portion d substantially coincides with the position of the centroid G of both cross sections of the suspension-side bent portion 11b and the brace-side bent portion 12b.

With this configuration, the vehicle width direction load F applied to the front wheel 20 in the vehicle width direction is substantially from the rear bush 4e of the lower arm 4 to the centroid G of the rear member 6. Accordingly, the lateral load F can be distributed to the rear member main body 11 and the brace member 12 in a substantially uniform manner. And since the offset with respect to the said input position of the centroid G of the bending parts 11b and 12b of both the members 11 and 12 can be made small, the bending moment which generate | occur | produces in both these bending parts can be made small, As a result, the support rigidity of the front wheel 20 can be improved.

Moreover, since the support rigidity of the front wheel 20 can be improved, the rubber hardness of the rear bush 4e of the rear arm 4c of the lower arm 4 can be lowered, and the ride comfort can be improved while ensuring steering stability.

In addition, since a relatively large space C is formed between the suspension-side bent portion 11b and the brace-side bent portion 12b, the differential mechanism 14 for the front wheel 20 and the engine unit, for example, can be connected using the space C. By inserting the propeller shaft 16 to be connected, the degree of freedom in layout of these vehicle parts can be improved.

Further, since the suspension-side bent portion 11b and the brace-side bent portion 12b are coupled by the support bracket 13, the rigidity of the rear member 6 can be greatly improved, and the support rigidity of the front wheel 20 can also be improved from this point.

Further, since the support bracket 13 of the front wheel differential mechanism 14 is coupled between the two bent portions 11b and 12b, the vibration of the drive system as in the case where the support bracket 13 is fixed to the floor panel 7 is generated. From being transmitted to the passenger compartment.

  In the above embodiment, the case where the suspension member 3 is separated into the front member 5 and the rear member 6 has been described. However, the present invention is applied to a suspension member in which the front member and the rear member are coupled. Of course, it is applicable.

DESCRIPTION OF SYMBOLS 1 Car body front part 2 Side member 4 Lower arm 4c 'Base end part 4e Support bush 11 Rear side member main body (suspension member)
11b Suspension side bent portion 12 Brace member 12b Brace side bent portion 13 Support bracket d Center portion G of support bush Centroid

Claims (2)

Left and right side members that are arranged on both sides in the vehicle width direction and extend in the vehicle front-rear direction, a suspension member that is suspended below both side members, and a base end portion of the suspension member that swings up and down In the front body structure of an automobile with a movably supported lower arm,
A suspension-side bent portion that forms a concave shape upward in the vehicle width direction center portion of the suspension member,
A brace member extending in the vehicle width direction is coupled to both ends of the suspension-side bent portion of the suspension member so as to bridge the suspension-side bent portion;
Forming a brace-side bent portion that is concave downward toward a portion of the brace member that faces the suspension-side bent portion of the suspension member;
A front body of an automobile characterized in that a center portion of a support bush provided at the base end portion of the lower arm is substantially coincident with a centroid position of both cross sections of the suspension side bending portion and the brace side bending portion. Construction. The front body structure of an automobile according to claim 1,
A front vehicle body structure for an automobile, wherein the suspension-side bent portion and the brace-side bent portion are coupled by a vehicle body component support bracket.

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