JP3912381B2 - Subframe mounting structure - Google Patents

Description

  The present invention relates to a subframe mounting structure in a vehicle such as an automobile, and more particularly to a subframe mounting structure in which the subframe does not bend and deform even in the event of a frontal collision of the vehicle.

A pair of left and right side members are arranged in the front and rear direction of the vehicle such as an automobile, and a subframe that supports heavy objects such as an engine and a transmission is supported below the side members. Has been. The front part of the subframe is supported below the front side member via bolts and nuts, and the front part of the subframe is supported at the lower part of the dash panel via bolts and nuts (for example, Patent Document 1). A bumper is attached to the front end of the front side member.
Japanese Patent Laid-Open No. 10-264862

  However, in the above-described conventional example, when the vehicle has a frontal collision, a collision load is input from the bumper to the front side member and the subframe is bent and deformed, thereby reducing the collision energy absorption amount and the reaction force of the collision load. May cause a drop.

  That is, since the front part of the subframe is fixed to the lower part of the front side member via bolts and nuts, when a collision load is input to the front side member, A bending moment that acts diagonally backward acts. When this bending moment acts on the subframe, the subframe tends to bend and deform.

  Therefore, an object of the present invention is to provide a subframe mounting structure in which the subframe does not bend and deform even in the event of a vehicle collision.

According to the present invention, a side member extending along the vehicle longitudinal direction is provided at the front end of the vehicle body, and a support member is extended downward from a lower portion of the side member, while an attachment portion is provided at the front portion of the subframe. In the sub-frame mounting structure in which a sub-frame is disposed below the side member by supporting the support member on a portion, the support is supported when a collision load of a predetermined value or more is input to the front end of the side member. The lower end portion of the support member is supported by the attachment portion of the sub frame so that the member moves in the vehicle front-rear direction with respect to the sub frame, and the lower end portion of the support member is formed into a spherical sliding member, The mounting portion of the frame is configured as a slide rail on which the sliding member slides, and at least the surface side of the lower end portion of the support member is formed of an elastic body .

  According to the present invention, even if the vehicle collides with the front, the subframe does not bend and deform, so that it is possible to efficiently absorb the collision energy and to suppress a reduction in reaction force due to the collision.

  That is, when the vehicle has a frontal collision, a collision load from the front end of the side member toward the rear of the vehicle is input, and the side member is crushed in the axial direction. Since the support member is fixed to the side member, the support member also moves to the rear of the vehicle as the side member axially collapses. However, since the lower end portion of the support member is slidably supported by the attachment portion of the subframe, the subframe does not bend and deform.

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

  FIG. 1 is a schematic cross-sectional view of a front portion of a vehicle body to which a subframe mounting structure according to an embodiment of the present invention is applied.

  An engine room 3 is provided at the front of the vehicle body 1, and a vehicle compartment 4 is formed on the vehicle rear side of the engine room 3. The engine room 3 and the vehicle compartment 4 are separated by a dash panel 5. It is separated. Further, a floor panel 7 is disposed at the lower part of the vehicle compartment 4, and a seat 9 is disposed at the upper part of the floor panel 7.

  On the other hand, a pair of left and right front side members 11, 11 are extended in the lower part of the engine room 3 along the vehicle front-rear direction. A frame 13 is attached.

  FIG. 2 is an enlarged cross-sectional view showing the vicinity of the subframe of FIG.

  The front side member 11 includes a bent portion 15 that is bent obliquely upward and forward from the lower end portion 5a of the dash panel 5, and an extending portion 17 that extends horizontally from the upper end of the bent portion 15 to the front of the vehicle. A bumper stay 19 and a bumper reinforcement 21, which are bumper reinforcement members, are disposed at the front end of the extended portion 17.

  On the other hand, the sub-frame 13 according to the present embodiment includes a sub-frame main body 23 that is disposed on the rear side and is formed in a substantially cross-beam shape, and a slide rail 25 that is fixed to the front portion of the sub-frame main body 23. A fixing bracket 27 extends downward from a center portion of the front side member 11 in the vehicle front-rear direction, and a support bracket 29 serving as a support member extends downward from the front end of the front side member 11. Yes. The front end and the rear end of the subframe main body 23 are fastened with bolts 31 to the lower end portion 5a of the bent portion 15 of the front side member 11 and the bottom surface of the fixing bracket 27 via a mounting member such as a rubber bush (not shown). Yes.

  3 is an enlarged sectional view taken along line AA in FIG. 2, and FIG. 4 is an enlarged perspective view showing the sliding rail in FIG.

  As shown in FIG. 3, a front side member 11 having a substantially rectangular cross section is disposed at the top, and a support bracket 29 is extended downward on the bottom surface 11 a of the front side member 11. Yes. The support bracket 29 is formed so that the width dimension gradually decreases as it goes downward, and a disc-shaped sliding member whose axial direction is arranged in the vertical direction at the lower end portion of the support bracket 29. 33 is attached. Although not shown, the sliding member 33 is formed of an elastic body such as synthetic resin or rubber, and the central portion in the radial direction is fixed to the lower end of the support bracket 29. Although the entire sliding member 33 is formed of an elastic body, only the surface side may be formed of an elastic body.

  In addition, a sliding part 35 for sliding the sliding member 33 of the support bracket 29 in the vehicle front-rear direction is formed on the upper stage of the sliding rail 25, and a rail main body part 37 is formed on the lower stage. The sliding portion 35 and the rail main body portion 37 are integrally formed by extruding an aluminum alloy. The sliding portion 35 includes a bottom surface 39 that vertically defines the sliding rail 25, a side surface 41 that extends upward from the left and right ends of the bottom surface 39, and a top surface 43 that extends inward from the upper end of the side surface 41. Has been. Further, a notch 45 extending in the vehicle front-rear direction is formed at the center of the upper surface 43 in the vehicle width direction, and the sliding member 33 can be slid along the notch 45 in the vehicle front-rear direction. As shown in FIG. 3, when the sliding member 33 of the support bracket 29 is housed in the sliding portion of the sliding rail 25, movement in the vehicle width direction and the vertical direction is restricted, so that Only movement is allowed. As the sliding member of the support bracket 29, a spherical sliding member 47 can be applied as shown in FIG. The entire sliding member 47 may be formed of an elastic body, or only the surface side may be cast with an elastic body. Further, the upper surface 51 constituting the sliding portion 35 is formed to be curved inward from the upper portion of the side surface 41 in correspondence with the upper shape of the spherical sliding member 47.

  The deformation behavior of the front side member 11 and the subframe 13 when a vehicle to which the subframe mounting structure having the above structure is applied causes a collision will be described with reference to FIGS.

  First, as shown in FIGS. 1 and 2, in a state before the vehicle collision, a bumper fascia 49 is attached to the front end of the front side member 11 via a bumper stay 19 and a bumper reinforcement 21. The front end 25a of the slide rail 25 is disposed on the vehicle rear side with respect to the front end of the bumper reinforcement 21 and at substantially the same position as the front end of the front side member 11 in the vehicle front-rear direction.

  Next, as shown in FIG. 6, when the vehicle has a frontal collision, a collision load F is input from the bumper fascia 49 to the front end of the front side member 11 via the bumper reinforcement 21 and the bumper stay 19. Due to the load F, the bumper reinforcement 21, the bumper stay 19 and the front side member 11 are crushed in the axial direction.

  Here, since the support bracket 29 is fixed to the front side member 11 and the sliding member 33 is attached to the support bracket 29, the support bracket 29 moves smoothly rearward of the vehicle together with the front side member 11, The frame 13 is not bent and deformed.

  FIG. 7 is a side view of the front side member and the subframe showing a state where a slight frontal collision has occurred.

  As shown in FIG. 7, when the vehicle has a slight frontal collision, a collision load f is input to the front end of the front side member 11 and the bumper reinforcement 21 and the bumper stay 19 are deformed. 11 does not undergo axial crushing deformation. Therefore, the support bracket 29 does not move backward, but the bumper reinforcement 21 and the bumper stay 19 which are bumper reinforcement members are axially crushed to prevent the subframe 13 from being deformed.

  Below, the effect by this embodiment is demonstrated.

  As shown in FIG. 4, the lower end portion of the support bracket 29 is formed on a disc-shaped sliding member 33 whose axial direction is arranged in the vertical direction, and the sliding member 33 is slid on the sliding rail 25. Since the moving part 35 is slidably accommodated, the support bracket 29 can be smoothly moved rearward when the front end of the front side member 11 undergoes axial crushing deformation at the time of a vehicle collision. In particular, the disc-shaped sliding member 33 can guide the smooth movement in the front-rear direction while suitably preventing the left-right and up-down tilting, and allows the sliding member 33 to rotate in the circumferential direction. be able to. Therefore, even when the collision load F is input to the vehicle obliquely from the front or when the front side member 11 is bent and deformed due to the vehicle collision, the support bracket 29 can be smoothly moved to the rear of the vehicle. Moreover, the operation | work which inserts and accommodates the sliding member 33 in the sliding part 35 of the sliding rail 25 becomes easy.

  Further, as shown in FIG. 5, if the lower end portion of the support bracket 29 is formed in a spherical sliding member 47, the support bracket 29 can be rotated in any of the front / rear, left / right and up / down directions, and is inclined to the vehicle. Even when the collision load F is input from the front or obliquely upward, the support bracket 29 can be smoothly moved rearward of the vehicle. Further, even when the collision load F is input to the vehicle obliquely from the front or when the front side member 11 is bent and deformed due to the vehicle collision, the support bracket 29 can be smoothly moved rearward of the vehicle.

  Furthermore, since the sliding members 33 and 47 of the support bracket 29 are made of an elastic body such as a synthetic resin or rubber, management of the dimensional accuracy and the like of the sliding members 33 and 47 becomes accurate and easy. Assembling workability for assembling the sliding members 33 and 47 to the sliding rail 25 is improved. Furthermore, even when the sliding members 33 and 47 hit the sliding rail 25 during traveling of the vehicle, since the sliding members 33 and 47 absorb the collision sound, it is possible to prevent the generation of lower sounds.

  As shown in FIG. 7, a bumper fascia 49 is disposed at the front end of the front side member 11 via a bumper reinforcement member made up of a bumper stay 19 and a bumper reinforcement 21, and the degree of collision. In the case of mild, only the bumper reinforcement 21 and the bumper stay 19 are crushed, and the front side member 11 is not crushed. That is, the front end position of the bumper reinforcement 21 after the collision is disposed on the front side of the vehicle with respect to the front end position of the slide rail 25, and the subframe 13 is prevented from being damaged when a light collision occurs. The vehicle repair cost can be reduced.

It is a schematic sectional drawing of the vehicle body to which the attachment structure of the sub-frame by embodiment of this invention is applied. It is an expanded sectional view which shows the sub-frame vicinity of FIG. It is an expanded sectional view by the AA line of FIG. It is a perspective view which expands and shows the support bracket and slide rail of FIG. It is a perspective view which expands and shows the support bracket and slide rail which arrange | positioned the spherical sliding member. It is a side view of a side member and a subframe showing a state where a frontal collision has occurred and is deformed. It is a side view of the side member and sub-frame which shows the state which raise | generates the mild frontal collision.

Explanation of symbols

F, f ... Collision load 1 ... Car body 11 ... Front side member (side member)
13 ... Subframe 19 ... Bumper stay (bumper reinforcement)
21 ... Bumper reinforcement (bumper reinforcement member)
25 ... Sliding rail (mounting part)
29 ... Support bracket (support member)
33, 47 ... sliding member 49 ... bumper fascia

Claims (2)

On the front end of the vehicle body, a side member extending along the vehicle front-rear direction is provided, and a support member is extended downward from a lower portion of the side member,
In the subframe mounting structure in which a subframe is disposed below the side member by providing a mounting portion at the front of the subframe and supporting the support member on the mounting portion.
The lower end of the support member is supported by the mounting portion of the subframe so that the support member moves in the vehicle longitudinal direction with respect to the subframe when a collision load of a predetermined value or more is input to the front end of the side member. then,
The lower end portion of the support member is formed into a spherical sliding member, and the attachment portion of the subframe is configured as a sliding rail on which the sliding member slides.
An attachment structure for a subframe, wherein at least a surface side of a lower end portion of the support member is formed of an elastic body . A bumper fascia is disposed at the front end of the side member via a bumper reinforcing member, and the front end position of the subframe is higher than the front end position of the bumper reinforcing member when the bumper reinforcing member is crushed due to a frontal collision of the vehicle. The sub-frame mounting structure according to claim 1 , wherein the rear frame is arranged on the vehicle rear side.

Images