JPH08169360A - Subframe construction for vehicle - Google Patents

Abstract

PURPOSE: To improve productivity of a side member and make the side member to be small-sized by fitting a second member of U-shaped section and small flange width into a first member of U-shaped section and large flange width so as to form the side member, and spot-welding respective flanges to each other so as to form a closed sectional structure. CONSTITUTION: In a side member 4, a second member 42 of outward U-shaped section and small width of flanges 42b is fitted into a first member 41 of outward U-shaped section and large width of flanges 41b. The flanges 41b, 42b are spot-welded to each other so as to form a closed sectional structure. The first member 41 is constituted of a depth wall 41a and the upper and lower flanges 41b, 41b, and corner parts 41c, 41c are formed at the corner parts so as to improve rigidity. The second member 42 is constituted of a depth wall 42a and the upper and lower flanges 42b, 42b. The flanges 41b, 42b are provided only on one side of the closed sectional structure constituted of the first and second members 41, 42, and hence the side member is made to be small-sized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a vehicle subframe structure.

[0002]

2. Description of the Related Art Conventionally, in order to mount a fuel tank below a rear portion of a vehicle body (such as below a rear seat), for example, a technique disclosed in Japanese Unexamined Patent Publication No. 5-8643 (fuel tank support device for automobiles) has been disclosed. 1 and 2 of the above publication.
As shown in FIG. 5, a suspension cross member 7 (corresponding to a subframe) having a substantially rectangular shape in plan view is mounted between the rear side frames 2 and 2 of the vehicle body 1, and the rear suspension device 6 is attached to the suspension cross member 7.
A supporting arm (consisting of upper arms 9 and 10, a lower arm 11 and a trailing arm 12) is supported, and further, a fuel tank 21 is supported by the suspension cross member 7. The fuel tank 21 is fixed to the suspension cross member 7 with a pair of belts (corresponding to bands) 23, 23.

The suspension cross member 7 includes front and rear support frames 14 and 15 (corresponding to cross members) extending in the vehicle width direction, and a left and right support frame 1 extending in the vehicle front and rear direction.
6, 17 (corresponding to side members). By the way, in order to reduce the weight, such support frames 14 to 17 are often a closed cross-section structure generally made of a press-formed material of a steel plate as shown in FIG.

FIGS. 6A to 6C are explanatory views of a conventional frame. A frame 101 shown in (a) is one in which an upper open lower member 101a and a lower open upper member 101b are fitted to each other, and a fitting portion is fillet-welded to form a closed cross-section structure. Since no flange is provided around 101, it is compact. In the frame 102 shown in (b), a lower member 102a having a hat-shaped cross-section that is open on the upper side and an upper member 102b that has a hat-shaped cross-section that is open on the lower side are stacked, and flanges are fillet-welded to form a closed cross-section structure. . The frame 103 shown in (c) is a lower member 10 with a hat-shaped cross section that is open on the upper side.
3a and the upper member 103b having a hat-shaped cross section that is open on the lower side are overlapped, and the flanges are spot-welded to form a closed cross-section structure.

On the other hand, the frame is provided with a bracket having a structure as shown in FIG. 7A and 7B are explanatory views of a conventional frame with a bracket. The frame 103 shown in (a) has the same structure as the frame shown in FIG. 6 (c), and a bracket 104 is welded to the upper portion, for example. However, when an excessive tensile load acts on the bracket 104, the welding strength between the flanges tends to be insufficient. In order to eliminate this point, it is conceivable to extend the base of the bracket downward and weld it to the lower member 103a as shown in FIG.

Further, a stiffener (reinforcing material) is provided on the frame by the procedure shown in FIG. 8 in order to improve rigidity. The frame 102 has the same structure as the frame shown in FIG. 6B. 8A to 8C are explanatory views of a conventional frame with a stiffener. As shown in (a), the stiffener 105 is attached between the lower member 102a and the upper member 102b. Explaining the coupling procedure, first, as shown in (b), the inner surface of the upper member 102b and the upper surface of the stiffener 105 are spot-welded, and then, as shown in (c), the lower member 102a and the upper member 102b are joined together. And the flanges are welded together, and finally the inner surface of the lower member 102a and the lower surface of the stiffener 105 are plug-welded to complete the connection.

[0007]

However, the above conventional structure has the following problems. In the frame 101 shown in FIG. 6A, it is necessary to control the fitting accuracy of the fitting portion in order to ensure fillet welding, but it is not easy to manage. In particular, when the frame 101 is bent, accuracy control is not easy and the productivity of the frame 101 is poor. Figure 6
The frames 102 and 103 shown in (b) and (c) are large in size because the flanges protrude on both sides. The frame 103 with the bracket 104 shown in FIG. 7B is not easy to mount because the bracket 104 extends over the flange, and is large in size. The frame 102 with the stiffener 105 shown in FIGS.
02 and the stiffener 105 are complicated, and there is also plug welding work, and the joining work is not easy, so the productivity is poor.

The object of the present invention is to (1) improve the productivity of the side member of the subframe, (2) reduce the size of the side member, and (3) easily attach the bracket of the side member, Moreover, it is to reduce the size of the bracket and (4) improve the productivity by easily attaching the stiffener in the side member.

[0009]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a vehicle subframe comprising a cross member extending in the vehicle width direction and a side member extending in the vehicle front-rear direction. A closed cross-section structure formed by fitting a first member having a U-shaped cross section and a sufficiently large flange width with a second member having a U-shaped cross section and a small flange width, and spot welding the flanges. Is a subframe structure for a vehicle.

Further, in the closed cross-section structure, a bracket is attached which extends over the upper surface and the back surface of the first member or over the back surface and the lower surface.

Further, the first member is reinforced by a stiffener with a flange.

[0012]

The side member is formed into a closed cross-section structure by fitting the second member to the first member and spot welding the flanges. Since the side member has the flange only on one side of the closed cross-section structure, the side member is small in size.

The bracket is attached across the upper surface and the back surface of the first member or across the back surface and the lower surface. Therefore, even if a tensile load is applied to the bracket, it does not affect the joining of the first member and the second member.

Since the stiffener is connected to the first member by the flange, it can be easily attached to the side member.

[0015]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In addition, "front", "rear", "left", "right",
“Upper” and “lower” follow the driver's direction, Fr is the front side, Rr is the rear side, L is the left side, R is the right side, CL is the vehicle width direction center, Up is the upper side, and Lo is the lower side. . Further, the drawings are to be viewed in the direction of reference numerals. FIG. 1 is a perspective view of a vehicle sub-frame structure according to the present invention. The sub-frame 1 has a substantially rectangular shape in plan view, and includes a front cross member 2, a rear cross member 3 extending in the vehicle width direction, and a vehicle body front-rear direction. The left side member 4 and the right side member 5, which extend to, are joined together.

Between the front and rear cross members 2 and 3, a pair of vertical support members 6 and 6 (one of which is not shown) disposed in the vicinity of the insides of the side members 4 and 5 are bridged, and the side member 4 is provided. , 5, a lateral support member 7 arranged at a substantially central position of the front and rear cross members 2 and 3 is bridged. The lateral support member 7 is coupled across the vertical support members 6 and 6 to reinforce the pair of vertical support members 6 and 6.

A fuel tank 11 (only the left half L is shown) is housed in the space surrounded by the front, rear, left and right members 2 to 5, and the fuel tank 11 includes vertical supporting members 6 and 6 and horizontal supporting members. Supported by 7. Further, between the rear cross member 3 and the trailing arm brackets 31 and 31 (which will be described later with reference to FIG. 2), a pair of bands 12 and 12 (one of which is not shown in the drawing) extending substantially in the front-rear direction of the vehicle body. No.) and both ends of these bands 12, 12 are bolts 1
3 ... (... indicates a plurality, the same applies hereinafter). Therefore, the upper surface of the fuel tank 11 is fixed to the subframe 1 by the band 12.

Rear suspensions 20, 20 are arranged on both left and right sides of the sub-frame 1, and these rear suspensions 20, 20 are rear multi-link type suspensions. The rear suspension 20 includes a shock absorber 21, a hub carrier 22 that supports the shock absorber 21, an upper arm 23, a lower arm 24, and a trailing arm 25 that support the hub carrier 22.
In addition, the control arm 26 includes a stabilizer rod 27 that connects the left and right hub carriers 22, 22.

FIG. 2 is a plan view of a vehicle subframe structure according to the present invention. Left and right side frames 51, 51 (shown by imaginary lines) extending in the vehicle front-rear direction are provided on the rear portion of the vehicle body, and these side frames are provided. The subframe 1 is passed between the frames 51 and 51. The four corners of the sub-frame 1 in plan view are suspended from the side frames 51, 51 via the vibration-preventing bushes 53. Therefore, the fuel tank 11 and the rear suspensions 20, 20 (see FIG.
(See below) is incorporated in the sub-frame 1, and the sub-frame 1 is passed between the side frames 51, 51 so that the lower part of the rear part of the vehicle body (the lower part of the rear seat or the rear floor).
To be installed on.

A trailing arm 25 is provided at the front corners of the front cross member 2 and the left and right side members 4, 5.
The left and right trailing arm brackets 31, 31 for mounting (see FIG. 1) are welded.

FIG. 3 is a side view of the vehicle subframe structure according to the present invention. Upper arm brackets 32, 32 for supporting the upper arm 23 are welded to the center of the upper portions of the side members 4, 5, respectively. Side members 4, 5
Lower arm brackets 33, 33 for supporting the lower arm 24 are welded to the center of the lower part of the lower arm 24, and a control arm bracket 34 for supporting the control arm 26 (see FIG. 1) is provided at the rear of each side member 4, 5. , 34 are welded.

FIG. 4 is a sectional view taken along line 4-4 of FIG. 3, showing the left side member 4. The left side member 4 is made of a combination of steel plate press-formed materials, and has a first member 41 having a U-shaped cross section outward in the vehicle width direction and a sufficiently large flange 41b width.
A closed cross-section structure is formed by fitting a second member 42 having a U-shaped cross section outward in the vehicle width direction and a small width of the flange 42b, and spot welding the flanges 41b and 42b to each other.

That is, the first member 41 has a back wall 41a,
Upper and lower flanges 41b extending laterally from the inner wall 41a,
41b. The second member 42 includes an inner wall 42a and upper and lower flanges 42b, 42 extending laterally from the inner wall 42a.
b. At the corners of the inner wall 41a and the flanges 41b and 41b, the corner portions 4 inclined at desired dimensions and angles are provided.
1c and 41c are formed. For this reason, the left side member 4 is polygonal in a hexagonal shape in cross section, so that the rigidity (rigidity of each surface, etc.) is increased. Particularly, as in this embodiment, a combination of thin plate press-formed materials is used. Is extremely effective in improving rigidity. Further, according to this embodiment, unlike the conventional technique shown in FIG. 7B, since the rear surface of the first member 41 does not have a flange, the corner portions 41c, 41 are provided.
c can be set freely.

An upper arm bracket 32 is attached by welding across the upper surface and the rear surface (outer wall 41a outer surface and upper corner 41c outer surface) of the first member 41. Also,
The lower arm bracket 33 is attached by welding across the back surface (the outer surface of the lower corner portion 41c) and the lower surface of the first member 41. According to this embodiment, unlike the prior art shown in FIG. 7 (b), since the first member 41 does not have a flange on the back surface, the upper / lower arm bracket 3
2 and 33 can be extended to the back surface of the first member 41 and welded with a small and simple structure, and the welding process can be simplified.

A stiffener with a flange 43 for reinforcing the first member 41 is provided in the first member 41.
The lower arm brackets 32 and 33 are attached to the attachment positions by welding. The lateral support member 7 is welded to the lower portion of the lower arm bracket 33.

FIG. 5 is an exploded perspective view of the left side member according to the present invention, and the left side member 4 has a vertically bent shape. The inner wall 42a of the second member 42 has an uneven portion (undulation) 42c for improving the rigidity of the second member 42.
... are formed. The stiffener 43 is made of a press-formed steel plate, has a U-shape in a plan view outward in the vehicle width direction, and has a rear wall 43a and a side wall 43 extending laterally from the rear wall 43a.
b, 43b, and flanges 43c at the upper and lower ends of these side walls 43b, 43b. The flanges 43c ... Are spot-welded to the flanges 41b, 41b of the first member 41.

At the front and rear ends of the first member 41, bush holders 52, 52 are provided between the upper and lower flanges 41b, 41b.
And vibration preventing bushes 53, 53 are attached to these bush holders 52, 52.

The rear end of the left side member 4 is closed by the control arm bracket 34, and the front end is closed by the blind lid 44 (welding the blind lid 44). Therefore, the left side member 4 has the first and second members 41, 42,
The control arm bracket 34 and the blind lid 44 form a completely closed structure to enhance rigidity. According to this embodiment, for closing the front and rear ends of the left side member 4,
The process is easier than the case where the front and rear ends of the first member 41 are closed by drawing, and a die for drawing is not required, and the cost can be reduced.

In order to close the front and rear ends of the left side member 4, instead of the control arm bracket 34 and the blind lid 44, the ends of the front and rear cross members 2 and 3 (see FIG. 2) are extended. It is also possible to put out. Also,
The inside of the left side member 4 can also serve as a guide for passing a harness or the like.

Next, the operation of the vehicle subframe structure having the above-mentioned structure will be described with reference to FIGS. 4 and 5. As shown in FIG. 4, the left side member 4 includes the first and second members 41, 42.
Flange 4 only on one side in the vehicle width direction of the closed cross section structure
Since it has 1b and 42b, it is small. In addition, the upper and lower arm brackets 32 and 33 include the first member 41.
Since it is connected only to the upper and lower surfaces and the back surface of the bracket 3,
Even if a tensile load is applied to 2, 33, it does not affect the coupling between the first member 41 and the second member 42. Furthermore,
The stiffener 43, as shown in FIG.
3c ... Can be easily attached only by spot welding the flanges 41b, 41b of the first member 41, and sufficiently reinforces the left side member 4.

The right side member 5 has the same structure and operation as the left side member 4 except that the right side member 5 is oriented in the left-right direction. Further, the brackets attached to the left and right side members 4, 5 may be only one of the upper part and the lower part. Further, the sub-frame 1 is characterized in that it is attached to the vehicle body, and the fuel tank 11
It is not limited to the configuration in which the rear suspension 20 is incorporated.

[0032]

Since the present invention is configured as described above, it has the following effects. The subframe structure for a vehicle according to claim 1, wherein the side member of the subframe is fitted to a first member having a U-shaped cross section having a sufficiently large flange width and a second member having a U-shaped cross section having a small flange width. Since the closed cross-section structure is formed by spot welding the flanges together, the productivity of the side member of the subframe can be improved, and the flange is provided only on one side in the vehicle width direction of the closed cross-section structure. The size of the member can be reduced.

According to the vehicle subframe structure of the second aspect, in the closed cross-section structure, since the bracket is attached across the upper surface and the back surface of the first member or over the back surface and the lower surface,
The bracket can be easily attached to the side member, and the bracket can be made small.

In the vehicle sub-frame structure according to the third aspect, the first member is reinforced by the stiffener with the flange, so that the stiffener can be easily mounted in the side member and the productivity can be improved.

[Brief description of drawings]

FIG. 1 is a perspective view of a vehicle subframe structure according to the present invention.

FIG. 2 is a plan view of a vehicle subframe structure according to the present invention.

FIG. 3 is a side view of a vehicle subframe structure according to the present invention.

FIG. 4 is a sectional view taken along line 4-4 of FIG.

FIG. 5 is an exploded perspective view of a left side member according to the present invention.

FIG. 6 is an explanatory diagram of a conventional frame.

FIG. 7 is an explanatory view of a conventional frame with a bracket.

FIG. 8 is an explanatory view of a conventional frame with a stiffener.

[Explanation of Codes] 1 ... Sub-frame, 2 ... Cross member (front cross member), 3 ... Cross member (rear cross member), 4 ... Left side member, 5 ... Right side member, 11 ... Fuel tank, 20 ... Rear suspension, 32 ... Upper arm bracket, 33 ... Lower arm bracket, 41 ...
1st member, 42 ... 2nd member, 43 ... Stiffener with a flange, 51 ... Side frame.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tsutomu Ogawa 1-4-1, Chuo, Wako-shi, Saitama, Honda R & D Co., Ltd. (72) Inventor Shinji Hinozawa 1-4-1, Wako-shi, Saitama No. Stock Company Honda Technical Research Institute

Claims (3)

[Claims] 1. A vehicle subframe including a cross member extending in the vehicle width direction and a side member extending in the vehicle front-rear direction, wherein the side member has a U-shaped cross section and a sufficiently large flange width. A subframe structure for a vehicle, which is a closed cross-section structure formed by fitting a second member having a U-shaped cross section and a small flange width, and spot-welding the flanges. 2. A subframe for a vehicle according to claim 1, wherein a bracket that extends over the upper surface and the back surface of the first member or that extends over the back surface and the lower surface of the first member is attached to the closed cross-section structure. Construction. 3. The vehicle subframe structure according to claim 1, wherein the first member is reinforced by a stiffener with a flange.