JPH058756A - Lower part structure of automobile - Google Patents

Abstract

PURPOSE:To provide a lower structure of an automobile in which a reinforcement laid orthogonal to a suspension cross member, for reinforcing the latter, or a shock absorbing part is provided in a coupling part which couples the reinforcement to the cross member. CONSTITUTION:The lower structure of an automobile incorporates a suspension cross member 13, a center member 20 orthogonal to the member 13, having its rear end coupled to the member 13 and its front end part coupled to a first cross member 7, a shock absorbing part 32 disposed in a center member 20 or a coupling part which couples the center member 20 to the cross member 13, for absorbing a shock inputted from the center member 29 to the suspension cross member 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle undercarriage, and more particularly to a suspension cross member reinforced by a center member in a direction orthogonal to the suspension cross member and a shock absorbing portion at a center member or a connecting portion of the center member to the cross member. Regarding the provided ones.

[0002]

2. Description of the Related Art Generally, in order to connect a front suspension and a rear suspension of an automobile to a vehicle body, a suspension cross member extending in a vehicle width direction is provided, and the suspension cross members are fixed to left and right side frames of the vehicle body at both ends thereof. To be done. For example, a suspension cross member for a front suspension is fixed to left and right front side frames at both ends thereof, and a suspension cross member for a rear suspension is fixed to left and right rear side frames at both ends thereof. The left and right ends of the are normally elastically supported by the left and right front side frames, but the other one or two supporting parts are often elastically supported by the suspension cross member. In particular, in the case of a front-wheel drive type vehicle, since the power unit is arranged in front of the suspension cross member,
In some cases, a supplementary auxiliary frame is provided in the front-rear direction in order to support the middle portion of the power unit in the vehicle width direction, and the rear end portion is connected to the suspension cross member. still,
Japanese Utility Model Laid-Open No. 62-92222 discloses a power unit support structure in which a support structure for supporting a support frame for supporting a power unit on a vehicle body is improved.

[0003]

Regarding the lower structure including the front suspension cross member, when a collision load acts on the suspension cross member via the power unit or the auxiliary frame at the time of collision of the vehicle, the collision load is large. It is conceivable that the collision will affect the passenger compartment. When the auxiliary frame is provided,
Since the suspension cross member is reinforced by the auxiliary frame, the safety at the time of collision is improved as compared with the case where the auxiliary frame is not provided. However, in order to support the power unit and sufficiently reinforce the suspension cross member, the conventional auxiliary frame was constructed of a member with sufficient strength and rigidity throughout the entire structure, so that it can absorb the impact during a vehicle collision. The effect was not sufficient. In particular, when the suspension cross member is made of aluminum or aluminum alloy in order to reduce the weight of the automobile, a reinforcing member such as an auxiliary frame and a shock absorbing mechanism are used because the suspension cross member has low strength / rigidity and shock absorbing ability. It is necessary to provide it.

An object of the present invention is to provide a lower structure of an automobile in which a shock absorbing mechanism is provided in a reinforcing member for reinforcing a suspension cross member or a connecting portion for connecting the reinforcing member to the suspension cross member.

[0005]

According to a first aspect of the present invention, there is provided a lower structure for an automobile, comprising: a suspension cross member which is arranged in a vehicle width direction of the automobile and fixed to a lower vehicle body at both ends; and a central portion in the vehicle width direction. In the front-rear direction of the vehicle body, one end of which is connected to the suspension cross member and the other end of which is connected to the front end portion or the rear end portion of the vehicle body, and the center member and the center member are suspended. And a shock absorbing portion provided on at least one of the connecting portions connected to the cross member and absorbing a shock input from the center member to the suspension cross member at the time of a collision.

According to a second aspect of the present invention, there is provided an automobile lower structure according to the first aspect, wherein the impact absorbing portion is
A folded U-shaped plate provided in the front-rear direction of the vehicle body at the connecting portion, the U-shaped plate having one end fixed to the center member and the other end fixed to the suspension cross member. It is characterized by that.

A substructure of an automobile according to a third aspect is the substructure of the automobile according to the first aspect, characterized in that the impact absorbing portion is formed on a center member.

According to a fourth aspect of the present invention, there is provided the lower vehicle structure according to the third aspect, wherein the shock absorbing portion is formed in the center member in the vicinity of the connecting portion from a weakly curved and low rigidity weak portion. It is characterized by becoming.

[0009]

In the substructure of the automobile according to claim 1,
A center member is provided which is disposed in the vehicle width direction central portion in the vehicle front-rear direction and has one end connected to the suspension cross member and the other end connected to the front end or rear end of the vehicle body. At least one of the connecting part that connects the center member to the suspension cross member and the connecting part that connects the center member to the suspension cross member are provided with a shock absorbing part that absorbs an impact input from the center member to the suspension cross member at the time of a collision. When a load is applied, the shock is absorbed by the shock absorbing portion, so that the shock transmitted to the suspension cross member is alleviated. Therefore, in the case of the lower structure of the front part of the automobile, the impact absorption portion of the center member absorbs the impact, so that the impact of the collision on the vehicle interior can be alleviated and the safety can be improved. In the case of the lower structure of the rear part of the automobile, the impact is absorbed by the impact absorbing portion of the center member in the same manner as described above, so that the impact of the collision on the vehicle interior can be alleviated and the safety can be improved.

In the vehicle substructure according to the second aspect, basically the same action as that of the first aspect can be obtained, and further, the impact absorbing portion is provided in the connecting portion in the front-rear direction of the vehicle body. The U-shaped plate is shaped like a U-shaped plate, one end of which is fixed to the center member and the other end of which is fixed to the suspension cross member. Since the U-shaped portion of the plate is deformed so as to move in the same direction as the collision load, the shock can be effectively absorbed with a simple configuration.

In the substructure of the automobile according to claim 3, basically the same action as in claim 1 is obtained, and since the shock absorbing portion is formed in the center member, it is related to the suspension cross member. The shock absorbing part can be configured without any, and the degree of freedom in designing and manufacturing is increased.

In the vehicle substructure according to the fourth aspect, basically the same action as that of the third aspect is obtained, and the shock absorbing portion has a gently curved shape formed on the center member in the vicinity of the connecting portion. Since it consists of a weak part with low rigidity,
The structure of the shock absorber can be simplified.

[0013]

As described in the above section, the following effects can be obtained. According to the lower structure of an automobile according to claim 1, a center member having one end connected to the suspension cross member and the other end connected to the front end or the rear end of the vehicle body is provided. By providing the shock absorbing portion on at least one of the connecting portion connected to the cross member, the shock is absorbed by the shock absorbing portion at the time of collision of the vehicle, so that the shock transmitted to the suspension cross member is reduced. As described above, by absorbing the impact by the impact absorbing portion, it is possible to reduce the influence of the collision with the vehicle interior and improve the safety.

According to the substructure of the automobile of claim 2, basically, the same effect as that of claim 1 is obtained, and in addition, the shock absorbing portion has one end fixed to the center member and the other end. U fixed to suspension cross member
Since it is configured by the character plate, the shock can be effectively absorbed by the simple configuration.

According to the substructure of the automobile of the third aspect, basically the same effect as that of the first aspect can be obtained, and since the shock absorbing portion is formed in the center member, it is related to the suspension cross member. The shock absorbing part can be configured without any, and the degree of freedom in designing and manufacturing is increased.

According to the substructure of the automobile of claim 4, basically, the same effect as that of claim 3 is obtained, and the shock absorbing portion is formed in the center member in the vicinity of the connecting portion and has a gently curved shape. In addition, the structure of the shock absorbing portion can be simplified by forming the weak portion having low rigidity.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. This embodiment is an embodiment in which the present invention is applied to the lower part of the front part of a front-wheel drive type automobile, and in the following description, the front, rear, left and right of the automobile will be described as front, rear, left and right. As shown in FIGS. 1 and 2, with respect to the vehicle body structure of the front part of the automobile 1, a pair of left and right front side frames 3 extending along the lower ends of the left and right wheel aprons 2 are provided. A wheel apron reinforcement 4 at the upper end thereof, a wheel house 5, and a suspension tower 6 are provided, the front end portions of the left and right front side frames 3 are connected by a first cross member 7, and the front ends of the left and right front side frames 3 are also connected. A bumper 8 is provided in the portion, and the rear ends of the left and right front side frames 3 are connected to cross members (not shown) having a closed cross section at the lower end of the dash lower panel 10 that continues below the cowl portion 9. . However, the rear end portions of the left and right front side frames 3 may be extended to the rear of the cross member, and the rear end portions of the front side frames 3 may be connected to the corresponding side sills 12.

In the rear of the engine room between the left and right wheel aprons 2, a suspension cross member 13 made of aluminum or aluminum alloy is arranged in the left-right direction, and a pair of left and right front ends of the suspension cross member 13 are provided. The first fixing portions 14 are fixed to the lower surface of the corresponding front side frame 3, and the pair of left and right second fixing portions 15 at the rear end of the suspension cross member 13 are provided below the corresponding cross member 11. It is fixed to the lower surface of the frame 3. A connecting portion 16 for connecting a link member of the suspension device is formed at a tip end of the extension portion extended to the outside of each of the first fixing portions 14, and a lower portion near each of the first fixing portions 14 is formed. A connecting portion 11 for connecting the base end portion of the forearm of the A-shaped suspension arm 18 supporting the front wheel 17 is formed on the side portion, and the extension portion extended to the outside of each second fixing portion 15 is formed. A connecting portion 19 for connecting the base end portion of the rear arm of the A-shaped suspension arm 18 is formed.

This suspension cross member 13 is
This is for attaching a shaft-like member (a rack and pinion mechanism, a power steering mechanism, etc.) of the steering mechanism, which supports the front suspension mechanism including the A-shaped suspension arm 18 and the like and which extends in the vehicle width direction. The suspension cross member 13 also has a function of supporting the power unit 21 including the engine and the transmission via the center member 20. An engine mount bracket 22 is provided on each front side frame 3 at a position corresponding to substantially the center of the left and right ends of the power unit 21 in the front-rear direction, and the left and right ends of the power unit 21 are elastically supported by the engine mount brackets 22. However, a center member 20 for supporting both front and rear ends of the power unit 21 in the vehicle width direction and for reinforcing the suspension cross member 13 is provided as follows.

The center member 20 is arranged in the front-rear direction at a substantially central portion in the vehicle width direction in front of the suspension cross member 13, and its front end is fixed to the first cross member 7 and its rear end is. It is fixed to the suspension cross member 13. The structure of the center member 20 will be described. As shown in FIGS. 3 to 5, the connecting support portion 23 of the front 1/3 portion of the center member 20 has a steel upper plate 23a and a pair of lower portions. The plate 23b is joined to form a substantially elongated triangular shape in a plan view, the remaining 2/3 of the main body 24 is made of a steel pipe member, and the rear end of the connection support 23 is connected to the main body 24. Of the front end portion of the first cross member 7 and the upper side portion of the front end portion of the first cross member 7 are overlapped and joined to each other, and a pair of bolt holes 25 are formed in the front end portion of the connection support portion 23. The front end portion of the center member 20 is fixed to the first cross member 7 via a pair of bolts that are brought into contact with the bolt holes 25 and are inserted into the bolt holes 25. Furthermore, the engine mount bracket 2 that supports the front end portion of the power unit 21 is connected to the connection support portion 23.
A mount portion 27 for fixing 6 is provided.

A flat portion 28 having a low rigidity is formed at a predetermined length portion on the front side of the rear end portion of the main body portion 24 by molding a pipe member into a horizontal flat shape (oblong cross section). Further, at the rear end portion of the main body portion 24, a plate-shaped portion 29 having a lower rigidity is formed by molding a pipe member into a horizontal double plate shape.
The rear portion of the plate-shaped portion 29 is the suspension cross member 1
3 is fixed to the lower surface of 3 through a rubber bush 30 with a bolt 31, and the flat portion 28 and the front portion of the plate-like portion 29 following the flat portion 28 are weakly curved downward as a whole (this is a shock absorbing portion). (Corresponding) is configured, and a weakly bent weakest portion 33 is formed at the boundary between the flat portion 28 and the plate-like portion 29.

The operation of the above-described automobile substructure will be described. Since the suspension cross member 13 made of aluminum or aluminum alloy and having relatively low strength and rigidity is connected to the first cross member 7 via the steel center member 20, the center member 20 sufficiently reinforces the suspension cross member 13. Since the center member 20 is small and lightweight, it is cost effective. At the time of a frontal collision of the automobile 1, a collision load is input to the center member 20 via the first cross member 7, but the weakest portion 33 of the center member 20 bends and then sequentially as shown by the phantom line during this collision. Since the flat portion 28 is bent and absorbs the impact, the impact on the suspension cross member 13 is significantly reduced. In particular, since the power unit 21 having a large mass can move independently of the suspension cross member 13 through the collapsing deformation of the weak portion 32 of the center member 20, the collision energy is also absorbed by the power unit 21, so that the suspension cross member 13 is absorbed. The impact on will be further alleviated. In the center member 20, the shock absorbing portion can be easily formed by a simple method of molding the rear end side portion of the body portion 24 made of a pipe member, and the manufacturing cost of the shock absorbing portion can be minimized. it can.

Next, a modified example of the shock absorbing portion of the above embodiment will be described. As shown in FIGS. 6 and 7, a low-rigidity straight flat portion 34 formed in a horizontal flat shape is formed at the rear end side portion of the main body portion 24A of the center member 20A. A U-shaped plate 35 is provided as a connecting member that connects the flat portion 34 to the suspension cross member 13. The U-shaped plate 35 corresponds to a shock absorbing portion that absorbs a shock transmitted from the center member 20 to the suspension cross member 13. The U-shaped plate 35 is brought into contact with the lower surface of the straight flat portion 34. The upper plate portion 36 and the front end portion of the upper plate portion 36 are inverted in a U-shape with a small radius and folded back downward to extend along the vicinity of the lower surface side of the upper plate portion 36.
And a pair of left and right mounting legs 38 that are raised from both sides of the rear end of the lower plate 37 are integrally formed, and the rear end of the upper plate 36 is The straight flat portion 34 is fixed to the rear end portion by a bolt 40, and the upper and lower mounting flange portions 39 of the pair of left and right mounting leg portions 38 are mounted.
, Respectively, are fixed to the lower surface of the suspension cross member 13 via the rubber bushes 42 by the bolts 41. The other structure of the center member 20 is the same as that of the center member 20.

The center member 20A and the U-shaped plate 35 are plastically deformed so that the U-shaped portion 35a of the U-shaped plate 35 sequentially moves rearward at the time of collision of the automobile 1 as shown by an imaginary line. Since the shock is absorbed by the shock absorber, the shock to the suspension cross member 13 is remarkably alleviated as described above. In the above embodiment, the case where one center member 20, 20A is provided has been described, but a plurality of center members may be provided, and the present invention can be applied to the rear suspension cross member in substantially the same manner. In that case, however, the rear end of the center member is connected to the cross member at the rear end of the vehicle body so as to absorb the shock to the suspension cross member at the time of a rear collision. The present invention can also be applied to the lower structure of a rear-wheel drive vehicle.

[Brief description of drawings]

FIG. 1 is a plan view of a front body structure and a lower structure of an automobile.

FIG. 2 is a perspective view of a front body structure and a lower structure of an automobile.

FIG. 3 is a plan view of a center member.

FIG. 4 is a vertical sectional side view of a center member and a suspension cross member.

5 is a sectional view taken along line 5-5 of FIG.

FIG. 6 is a vertical sectional side view of a main part of a lower structure according to a modification.

FIG. 7 is a perspective view of a U-shaped plate.

[Explanation of symbols]

3 front side frame 13 Suspension cross member 20, 20A Center member 28 Flat part 29 Plate 32 Shock absorber 35 U-shaped plate

Claims (4)

[Claims] 1. A suspension cross member which is disposed in the vehicle width direction of an automobile and fixed to a lower vehicle body at both ends, and a suspension cross member which is disposed in the vehicle width direction central portion in the vehicle front-rear direction and has one end portion suspended. The center member is connected to the cross member and the other end is connected to the front end portion or the rear end portion of the vehicle body, and is provided on at least one of the center member and the connecting portion connecting the center member to the suspension cross member, A lower structure for an automobile, comprising: a shock absorbing portion that absorbs a shock input from the center member to the suspension cross member in the event of a collision. 2. The shock absorbing portion is a folded U-shaped plate provided in the connecting portion in the vehicle front-rear direction, one end of which is fixed to the center member and the other end of which is a suspension cross member. The substructure of the automobile according to claim 1, wherein the substructure is composed of a U-shaped plate fixed to the. 3. A lower structure of an automobile, wherein the shock absorbing portion is formed on a center member. 4. The substructure of the automobile according to claim 3, wherein the shock absorbing portion is a weakly curved and low-rigidity weak portion formed in the center member in the vicinity of the connecting portion.