JP2012148728A - Subframe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a subframe which is bent downward in a body on collision even when a part of the frame is arranged on the upper side from a fixed point on the vehicle center side.SOLUTION: The subframe 10 is attached on the under side of a pair of right and left side members arranged in the vehicle length direction, has a pair of right and left side pipes 11 and has protrusion parts 11c whose position is higher than the bolt fixed point FP of the vehicle center side, disposed on a part of horizontal parts 11b to 11d of the side pipes 11, wherein reinforcing members 17 each of which is a folded part of the side pipe 11 formed when disposing the protrusion parts 11c and has one side end part located lower than the bolt fixed point FP while striding before and after the folded part of the vehicle center side from the protrusion part 11c are disposed such that the folded point BP on the collision are located lower than the bolt fixed point FP by the reinforcing members 17.

Description

  The present invention relates to a subframe constituting a vehicle body structure.

  As a vehicle body structure (chassis member) of a vehicle, a pair of left and right side members are arranged along the vehicle length direction on the side of the vehicle. For example, on the front side of the vehicle, a subframe is attached below the side member. It has been. The subframe is composed of a pair of left and right side pipes and two cross pipes that connect the side pipes, and has a cross beam shape when viewed from above. An engine, a driving device, a steering device, and the like are attached on such a subframe.

  In the conventional subframe, in order to absorb the impact of a collision in the vehicle length direction, a folding part (folding angle) is provided in the side pipe, and the rear end side (vehicle center side) fixing point to the side member (body side) Further, the folding part (folding angle) is arranged below or horizontally, and the subframe is bent downward at the time of a collision so that the subframe is released to the lower side of the body.

JP 2008-018778 A JP 2009-073243 A JP 2005-186727 A

  Depending on the vehicle layout, it may be desired to place a part of the subframe above a fixed point on the rear end side (vehicle center side). In such a case, the folded part (fold angle) of the side pipe may also be above the fixed point on the rear end side (vehicle center side), and in this case, the subframe bends upward at the time of collision (described later). 5) of the body side, such as a dash panel or the like.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a subframe that bends downward in the body at the time of collision even when part of the vehicle is disposed above a fixed point on the vehicle center side.

A subframe according to the first invention for solving the above-mentioned problem is as follows:
A sub-frame having a pair of left and right side pipes attached to a lower side of a pair of left and right side members arranged in the vehicle length direction. In the subframe with the protruding part with a high position,
The side pipe fold formed when the projecting portion is provided, straddling the front and rear of the fold portion on the vehicle center side from the projecting portion, and having one end lower than the fixed point A reinforcing member serving as a position is provided, and the bending point at the time of collision is set to a position lower than the fixed point by the reinforcing member.

A subframe according to a second invention for solving the above-mentioned problem is as follows:
In the subframe described in the first invention,
The surface of the one end of the reinforcing member attached to the side pipe is formed perpendicular to the axis of the side pipe.

A subframe according to a third invention for solving the above-mentioned problem is as follows:
In the subframe described in the first or second invention,
A bracket for attaching the suspension is provided on the protruding portion, and the other end of the reinforcing member is attached to the bracket.

A subframe according to a fourth invention for solving the above-mentioned problem is as follows.
In the subframe described in the third invention,
The bracket and the reinforcing member are integrated.

  According to the present invention, even when a part of the side pipe is disposed above the fixed point on the vehicle center side, the reinforcing member is provided at the folded portion of the side pipe so that the break point of the side pipe at the time of the collision is the center of the vehicle. Since it is below the fixed point on the side, the side pipe bends downward in the body at the time of collision from the vehicle length direction and escapes to the lower side of the body, thereby improving collision safety.

It is a perspective view showing an example of an embodiment of a subframe concerning the present invention. (A) is a top view of the subframe shown in FIG. 1, and (b) is a side view of the subframe shown in FIG. It is a figure which shows the reinforcement member attached to the sub-frame which concerns on this invention, (a) is the perspective view, (b) is the top view, (c) is the side view. It is a figure which shows the sub-frame before reinforcement member attachment, (a) is the top view, (b) is the side view. It is a side view which shows the collision experiment result in the sub-frame before the reinforcement member attachment shown in FIG. It is a side view which shows the collision experiment result in the sub-frame after the reinforcement member attachment shown in FIGS. It is a bottom view which shows the collision experiment result in the sub-frame after attaching the reinforcement member shown in FIGS.

  Hereinafter, embodiments of a subframe according to the present invention will be described with reference to FIGS. Here, the subframe on the vehicle front side is illustrated and described, but the present invention is also applicable to the subframe on the vehicle rear side.

Example 1
FIG. 1 is a perspective view showing a sub-frame of this embodiment, FIG. 2 (a) is a top view thereof, and FIG. 2 (b) is a side view thereof. 3A is a perspective view of a reinforcing member attached to the subframe, FIG. 3B is a top view thereof, and FIG. 3C is a side view thereof. In order to explain the configuration of the present embodiment, FIG. 4A shows a top view and FIG. 4B shows a side view of the subframe before the reinforcement member is attached. In addition, in order to explain the effect of the present embodiment, FIG. 5 is a side view of a collision experiment result in the subframe before attaching the reinforcing member shown in FIG. 4, and FIGS. The side view and bottom view of the collision experiment result in the sub-frame after the reinforcement member attachment shown in FIG. 2 are illustrated.

  The subframe 10 of the present embodiment mainly includes a pair of left and right side pipes 11 and two cross pipes 12a and 12b that connect the side pipes 11 and has a cross beam shape in a top view. Although not shown, an engine, a drive device, a steering device, and the like are mounted on the subframe 10. A number of brackets for attaching an engine, a driving device, a steering device, and the like are provided on the subframe 10, but only the main brackets are shown here.

  The side pipe 11 and the cross pipes 12a and 12b are made of, for example, a cylindrical (pipe-shaped) steel pipe and have a hollow cross section. The pair of side pipes 11 are disposed below the left and right side members along substantially the same vehicle length direction as the side members, and are symmetrical to each other. The cross pipes 12a and 12b are arranged in the vehicle width direction, are fixed by welding or the like, and connect the left and right side pipes 11 to each other. Reinforcing stays 15 are provided between the side pipes 11 at both ends of the rear cross pipe 12b. As the stay 15, for example, a reinforcing function is achieved by applying a bead or the like to a flat plate-shaped member.

  The side pipe 11 is bent so as to be substantially L-shaped in a side view, and mainly includes a vertical portion 11a that rises vertically upward and horizontal portions 11b to 11d that are substantially horizontal, and the vertical portion 11a. Is arranged on the front side of the vehicle. A fixed bracket 13 is attached to the front end portion of the side pipe 11, and an insertion hole 14 a is provided in the fixed bracket 13. An insertion hole 14 b is also provided at the rear end portion of the side pipe 11.

  Although illustration is omitted, as a vehicle body structure of the vehicle, a pair of left and right side members are arranged along the vehicle length direction on the side of the vehicle. And the sub-frame 10 is attached to the lower side of a side member by inserting a volt | bolt in the insertion holes 14a and 14b mentioned above, and fastening with a nut. That is, the insertion hole 14a is a bolt fixing point on the front end side to the body side (side member), and the insertion hole 14b is a bolt fixing point on the rear end side (vehicle center side) to the body side (side member). Here, the bolt fixing point on the rear end side is referred to as FP for use in the following description.

  In the present embodiment, the horizontal portions 11b to 11d of the side pipe 11 are substantially horizontal as a whole, but by bending, the middle horizontal portion 11c protrudes upward and is higher than the horizontal portions 11b and 11d. The position. Hereinafter, the horizontal portion 11c is referred to as a protruding portion 11c, and is distinguished from the horizontal portions 11b and 11d.

  A suspension bracket 16 having a U-shaped cross section is attached to a position of the protruding portion 11c outside the vehicle, and a suspension lower arm is attached to the suspension bracket 16. Thus, when it is desired to attach the lower arm of the suspension to a high position in the vehicle layout, a part of the horizontal portion (projecting portion 11 c) of the side pipe 11 to which the suspension bracket 16 is attached is increased.

  Further, the projecting portions 11c are connected to each other by the cross pipe 12b and the stay 15, and the strength for holding the suspension is ensured.

  In addition, when viewed from the top, the side pipe 11 is bent so that the horizontal portion 11d is arranged in a C shape when viewed from the vehicle center side (vehicle rear side). Although details will be described later with reference to FIG. 7, since the horizontal portion 11d is arranged in a U shape, the side pipe 11 bends around the bolt fixing point FP (insertion hole 14b) at the time of collision. It will be.

  As described above, since the side pipe 11 is bent and the protruding portion 11c is provided, a downward folding portion (fold angle) is formed immediately behind the protruding portion 11c (vehicle center side). . Therefore, the folding point BP0 at the time of the collision is set at the position of this folding part (folding angle), and as a result, the position of the folding point BP0 is also higher than the bolt fixing point FP (FIG. 4 ( a) and (b)).

  In addition, in the present embodiment, the suspension bracket 16 is provided on the projecting portion 11c, and the suspension bracket 16 functions like a so-called reinforcing member. The folding part (folding angle) of the side pipe 11 immediately behind the part 11c becomes the folding point BP0 at the time of collision.

  If the break point BP0 is higher than the bolt fixing point FP, the break point BP0 is bent upward as shown in FIGS. 4B and 5 at the time of collision.

  Therefore, in the present embodiment, the reinforcement in which one end (the vehicle center side) is positioned lower than the bolt fixing point FP across the front and rear of the folding portion on the rear side (vehicle center side) of the projecting portion 11c. A member 17 is provided.

  For example, the reinforcing member 17 has one end attached to the outer peripheral surface of the cylindrical side pipe 11 and the other end attached to a suspension bracket 16 having a U-shaped cross section. Is provided to extend backward.

  More specifically, the reinforcing member 17 basically has a U-shaped cross section. As shown in FIG. 3, the first joint portion 17 a welded to the suspension bracket 16 is provided on the suspension bracket 16. It is formed according to the shape. On the other hand, in the second joint portion 17 b that is welded to the outer periphery of the side pipe 11, the joint portion is cut out into a semicircular shape in accordance with the shape of the side pipe 11 so as to be attached to the outer peripheral surface of the side pipe 11. Further, the surface forming the second joint portion 17b is formed so as to be bent at a right angle or a substantially right angle with respect to the axis of the side pipe 11 of the portion to be welded. In other words, the substantial cross section around the side pipe 11 is abruptly changed at the rear (vehicle center side) end of the reinforcing member 17.

  In this way, one end portion (second joint portion 17b) of the reinforcing member 17 is welded to the outer periphery of the side pipe 11, and the other end portion (first joint portion 17a) of the reinforcing member 17 is a suspension bracket. 16, the reinforcing member 17 is disposed so as to straddle the front and rear of the folding portion (folding angle) immediately behind the protruding portion 11c. The area of the cross section including the side pipe 11, the suspension bracket 16, and the reinforcing member 17 changes abruptly at a portion of the second joint portion 17 b that joins at right angles or substantially right angles to the axis of the side pipe 11. Therefore, a new break point BP is set immediately behind the reinforcing member 17, and the position thereof is lower than the bolt fixing point FP (see FIGS. 2A and 2B).

  Here, the difference in deformation mode depending on the presence or absence of the reinforcing member 17 will be described with reference to FIGS.

  FIG. 5 is a side view showing a collision experiment result in the subframe 10 (without the reinforcing member 17) shown in FIG. As shown in FIG. 5, when an impact from the vehicle length direction is applied, the side member 18 is compressed in that direction and deformed so as to be crushed. As the side member 18 is deformed, the side pipe 11 is also deformed, and the vertical portion 11a is bent backward by the side member 18, but the horizontal portions 11b to 11d are bent upward at the break point BP0. In this case, the subframe 10 collides with the dash panel 19 provided in the vicinity of the subframe 10 (see region A in FIG. 5), and the vehicle body (particularly, the passenger compartment) is greatly deformed.

  On the other hand, FIGS. 6 to 7 are a side view and a bottom view showing a collision test result in the subframe 10 (with the reinforcing member 17) shown in FIGS. As shown in FIG. 6, when an impact from the vehicle length direction is applied, the side member 18 is compressed in that direction and deformed so as to be crushed. As the side member 18 is deformed, the vertical portion 11 a of the side pipe 11 is also deformed. To bend backwards. On the other hand, in the horizontal portions 11b to 11d of the side pipe 11, since the reinforcing member 17 is provided, the side pipe 11 is bent downward at the break point BP. In this case, the sub-frame 10 does not interfere with the dash panel 19 provided in the vicinity of the sub-frame 10 (see region B in FIG. 6), and the vehicle body (particularly the vehicle compartment) is not deformed.

  Further, as shown in FIG. 7, each side pipe 11 of the subframe 10 is bent into a U shape so as to rotate inward and rearward of the vehicle with the bolt fixing point FP as a rotation center.

  In this way, the reinforcing member 17 provides a position where the cross-sectional area changes suddenly, and the break point BP moves to a position below the bolt fixing point FP. Therefore, the side pipe 11 is bent so as to escape downward. . As a result, interference between the side pipe 11 and the vehicle body at the time of a collision can be avoided, and deformation of a dash panel provided in the vicinity can be suppressed to improve collision safety.

  In this embodiment, the suspension bracket 16 and the reinforcing member 17 are independent members. However, the suspension bracket 16 and the reinforcing member 17 may be integrally formed.

  The sub-frame according to the present invention is suitable as a front vehicle body structure, but can also be applied as a rear vehicle body structure. Moreover, it is applicable not only to an engine vehicle but also to an electric vehicle (EV vehicle).

DESCRIPTION OF SYMBOLS 10 Sub-frame 11 Side pipe 12a, 12b Cross pipe 13 Fixed bracket 14a, 14b Insertion hole 15 Stay 16 Suspension bracket 17 Reinforcement member 18 Side member 19 Dash panel

Claims (4)

A sub-frame having a pair of left and right side pipes attached to a lower side of a pair of left and right side members arranged in the vehicle length direction. In the subframe with the protruding part with a high position,
The side pipe fold formed when the projecting portion is provided, straddling the front and rear of the fold portion on the vehicle center side from the projecting portion, and having one end lower than the fixed point A subframe characterized in that a reinforcing member serving as a position is provided, and the folding point at the time of collision is set to a position lower than the fixed point by the reinforcing member. In the subframe of claim 1,
A sub-frame, wherein a surface of the one end of the reinforcing member attached to the side pipe is formed perpendicular to the axis of the side pipe. In the subframe according to claim 1 or 2,
A subframe in which a bracket for attaching a suspension is provided at the projecting portion, and the other end of the reinforcing member is attached to the bracket. In the subframe of claim 3,
A sub-frame, wherein the bracket and the reinforcing member are integrated.

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