JP3354301B2 - Subframe structure in automobile - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile having a subframe mounted on a body frame and supporting left and right suspensions on the subframe, and more particularly to a subframe structure.

[0002]

2. Description of the Related Art As such a subframe structure, one described in Japanese Patent Application Laid-Open No. Hei 5-193519 is known.

[0003] This sub-frame is formed by connecting two members, a front side and a rear side, in a hollow frame shape with bolts, and a plurality of brackets for supporting a suspension arm are provided on both left and right sides thereof.

[0004]

In the above-mentioned conventional sub-frame, since brackets are provided corresponding to the respective suspension arms, a large number of brackets are required and the number of parts and the number of assembling steps increase. Or, there is a problem that it is difficult to obtain the positional accuracy between the support points of the suspension arm.

The present invention has been made in view of the above circumstances, and has as its object to firmly and accurately support a suspension arm on a subframe without increasing the number of parts and the number of assembly steps.

[0006]

In order to achieve the above object, an invention according to claim 1 is directed to an automobile having a subframe mounted on a body frame and supporting left and right suspensions on the subframe. , Left and right side members respectively provided on the left and right sides of the subframe
Extend in the front-rear direction and are separated from each other in the vertical direction
Composed of upper and lower side members
And between the middle part in the front-rear direction of the lower side member,
Integrally connected by a bracket extending in the vertical direction, characterized in that respectively support the upper arm and lower arm of the suspension in the upper end and the lower end of the bracket.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, an upper portion of the bracket is provided with the upper portion.
It is characterized in that it extends above the side members .

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 7 show an embodiment of the present invention. FIG. 1 is a plan view of a subframe assembly, FIG. 2 is a perspective view of the subframe assembly, and FIG. 3 is an enlarged sectional view of FIG. 4, FIG. 4 is an enlarged sectional view of line 4-4 in FIG. 1, FIG. 5 is an enlarged view of a main part of FIG. 4, FIG. 6 is a perspective view of a subframe, and FIG. It is an expanded sectional view.

As shown in FIGS. 1 and 2, the sub-frame assembly SA is supported by a pair of left and right body frames MF, MF extending in the front-rear direction at the rear part of the body, and has a substantially rectangular frame shape in plan view. , A fuel tank FT, a pair of left and right rear suspensions RS supporting the left and right rear wheels Wr, Wr, a rear differential RD, and an exhaust unit EU. The sub-frame assembly SA is assembled in advance in an assembly line separate from the vehicle body assembly line, and then the body frames MF, MF of the vehicle body flowing on the body assembly line.
Is mounted in a lump.

As shown in FIGS. 6 and 7, the sub-frame SF includes a front cross member 1 extending in the left-right direction of the vehicle body.
A rear cross member 2 extending in the left-right direction of the vehicle body behind the front cross member 1, a pair of left and right upper side members 3 extending in the vehicle front-rear direction by connecting the left and right ends of the two cross members 1 and 2; Both upper side members 3,3
A pair of left and right lower side members 4 and 4 extending in the front-rear direction of the vehicle body by connecting the two cross members 1 and 2 on the lower side and inside the vehicle body. Each of the front cross member 1, the rear cross member 2, the upper side members 3, 3 and the lower side members 4, 4 has a rigid box section. The upper side member 3 and the lower side member 4 forming a pair constitute a side member SM.

The upper side members 3, 3 are located at a position higher than the lower side members 4, 4, and both side members 3, 3 are provided.
3, 4 and 4 are connected by first brackets 5 and 5 extending in the vertical direction at the middle part in the vehicle longitudinal direction. The lower portions of the first brackets 5, 5 constituting the connecting member of the present invention are welded to the outer surfaces and upper surfaces of the lower side members 4, 4, and the intermediate portions thereof are formed on the outer surfaces of the upper side members 3, 3, and It is welded to the upper and lower surfaces, and its upper portion extends above the upper side members 3, 3.

The front cross member 1 and the left and right upper side members 3, 3 are connected by a pair of second brackets 6, 6. A pair of third brackets 7, 7 are provided at the rear ends of the left and right upper side members 3, 3, and a pair of fourth brackets 8, 8 are provided on the lower surface of the rear cross member 2.

At the four corners of the sub-frame SF, that is, at the joints between the front cross member 1 and the rear cross member 2 and the left and right upper side members 3, 3, the sub-frame SF is elastically supported on the body frames MF, MF. Four rubber bush mounts 9 are provided.

As is clear from FIGS. 1, 6 and 7,
Each rear suspension RS is a multi-link type, and includes a knuckle 10 that rotatably supports the rear wheel Wr,
An upper arm 11 for connecting the knuckle 10 to the upper end of the first bracket 5, a lower arm 12 for connecting the knuckle 10 to the lower end of the first bracket 5, and a second arm
A trailing arm 13 connected to the bracket 6, a leading arm 14 connecting the knuckle 10 to the third bracket 7, a control arm 15 connecting the knuckle 10 to the fourth bracket, and a damper 16 connecting the knuckle 10 to the vehicle body. Consists of

As described above, the upper side members 3, 3
Since the front and rear intermediate portions of the lower side members 4 and 4 are connected to each other by the brackets 5 and 5, the rigidity of the subframe SF is extremely high near the brackets 5 and 5, and at the same time, the rigidity of the brackets 5 and 5 itself is increased. Is also enhanced. Since the upper arms 11, 11 and the lower arms 12, 12 are supported on the upper and lower ends of the high-rigidity brackets 5, 5, the load from the rear wheels Wr, Wr is applied to the upper side members 3, 3 and the lower side members 4, 4. Not only can it be distributed and received, but also the rear suspension R
The lateral rigidity and camber rigidity of S and RS are improved, and the positional accuracy between the upper arms 11 and 11 and the lower arms 12 and 12 is improved. Further, the upper arms 11, 1
Compared to the case where the bracket for one and the bracket for the lower arms 12 and 12 are separately welded, the number of parts and the number of welding steps can be reduced and cost can be reduced.

As is apparent from FIGS. 3 and 6, the rear differential RD is a differential case 17.
And a front end of the support arm 18 is elastically supported by a rubber bush 20 provided on a bracket 19 protruding from the upper surface of the front cross member 1 of the sub-frame SF. On the other hand, a pair of left and right pins 21, 2 extending rearward from the differential case 17.
1 is fitted and elastically supported by a pair of left and right rubber bushes 22 provided on the rear cross member 2 of the sub-frame SF.

A propeller shaft 23 extending forward from the differential case 17 passes above the front cross member 1. The axles 24, 24 extending from the differential case 17 to the left and right sides are the knuckles 10, 1.
0 and is connected to the rear wheels Wr, Wr.

As is apparent from FIGS. 1 to 4, the fuel tank FT is formed by blow molding a synthetic resin, and the lower surface of the fuel tank FT accommodates the rear differential RD.
A tunnel portion 25 penetrating in the front-rear direction is recessed. The rear differential RD is disposed at the rear of the tunnel section 25, that is, at a position near the rear cross member 2 inside the sub-frame SF. The thickness of the fuel tank FT is thinner above the tunnel portion 25, and two welded portions 26, 26 (see FIG. 3) for joining the upper wall and the lower wall of the fuel tank FT are formed in that portion. Is done.

The front part of the fuel tank FT is a sub-frame SF
(See FIGS. 3 and 4). As a result, the tunnel 2
5, the reduced capacity of the fuel tank FT is compensated for, and the capacity of the fuel tank FT can be sufficiently ensured as a whole.

A pair of band holes 27, 27 penetrating up and down are formed at the left and right front portions of the fuel tank FT, and two band grooves 28, 28 are formed from the band holes 27, 27 behind the fuel tank FT. It extends backward to the end. The rear portion of the fuel tank FT is placed on a pair of left and right fuel tank contact surfaces 2 ₁ , 2 ₁ (see hatched portions in FIG. 6) formed on the right and left upper surfaces of the rear cross member 2. The parts are the front cross member 1 and the left and right lower side members 4, 4.
A pair of left and right fuel tank contact surfaces 1 ₁ , ₁
4 _{1; 1} 1, 4 ₁ is placed on (see the hatched portion in FIG. 6).

As is clear from FIGS. 2, 4 and 5,
Front mounting parts 29, 29 and rear mounting parts 30,
The two fuel tank fixing bands 31, 31 having fittings 30 and fitting into the band grooves 28, 28 are formed in the band holes 27, 2 respectively.
7, the front mounting portions 30, 30 are fixed to the upper surface of the front cross member 1 by bolts 32, 32, and the rear mounting portions 31, 31 are
The upper and lower members 3 and 33 are fixed to the upper surface of the rear cross member 2.

As described above, the rear differential RD
The two fuels of the pair of fuel tanks abutment surface 2 ₁ that supports the rear lower surface of the fuel tank FT to firm the rear cross member 2 which supports the majority of the load, 2 ₁ is formed to secure the fuel tank FT since the tank affixing band 31, 31 is fixed to the rear cross member 2 in the vicinity of the fuel tank abutment surface 2 _1, 2 _1, not only the fuel tank FT can be held firmly, the fuel tank FT A special member for supporting is not required, which is advantageous in both cost and weight.

The fuel tank fixing bands 31, 31
Is fixed to the sub-frame SF with the band holes 27, 27 formed in the fuel tank FT penetrating therethrough.
The shape of the fuel tank FT can be freely set irrespective of the shape of the sub-frame SF, so that not only can the capacity of the fuel tank FT be increased, but also the sub- Frame S
The attachment point for F can be set freely.
Further, since the length of the fuel tank fixing bands 31, 31 can be reduced by the band holes 27, 27, the weight can be reduced and the mounting operation can be facilitated. Moreover, since the fuel tank fixing bands 31, 31 are positioned by the band holes 27, 27 and the band grooves 28, 28, the displacement of the fuel tank FT can be reliably prevented.

As is apparent from FIG. 1, the exhaust unit E
U denotes a front exhaust pipe 34 extending in the front-rear direction of the vehicle body, and a left rear exhaust pipe 36 and a right rear exhaust pipe 37 connected to a rear end of the front exhaust pipe 34 via a joint 35 and branched in the left-right direction.
And a pair of left and right silencers 38, 38 connected to the rear ends of both rear exhaust pipes 36, 37. The front exhaust pipe 34 is housed inside the tunnel portion 25 of the fuel tank FT, and the propeller shaft 24 along the vehicle body center line.
Is located to the left of

The exhaust unit EU suspended and supported by the sub-frame SF has its silencers 38, 38 projecting rearward from the rear cross member 2 of the sub-frame SF. Therefore, the front part of the fuel tank FT is
As described above, even if the center of gravity of the sub-frame assembly SA is moved forward by projecting forward from the front cross member 1 of F, the rear differential RD is moved rearward so as to approach the rear cross member 2 as described above. In addition to the effect of disposing the center of gravity of the sub-frame assembly SA and the position of the center of gravity of the sub-frame assembly SA, the position of the center of gravity of the sub-frame assembly SA is reduced by the weight of the silencers 38 projecting rearward from the rear cross member 2. Can be held at a substantially central position.

As a result, when the sub-frame assembly SA is pre-assembled on an assembly line separate from the vehicle body assembly line, the posture of the sub-frame assembly SA on the pallet can be stabilized to improve work efficiency. it can.
Further, when the sub-frame assembly SA is mounted on the body frames MF of the vehicle body flowing on the vehicle body assembly line,
Since the position of the center of gravity is located substantially at the center of the sub-frame SF (see FIG. 1), the four rubber bush mounts 9 are provided.
And substantially equalize the load applied to ... to sufficiently exhibit a vibration reduction function, yet four rubber bushes mount 9 ... a made common Ru can reduce the cost.

Although the embodiments of the present invention have been described in detail above, various design changes can be made in the present invention without departing from the gist thereof.

For example, in the embodiment, the sub-frame SF is formed in a frame shape by the front cross member 1, the rear cross member 2, and the left and right side members SM.
Either the front cross member 1 or the rear cross member 2 can be eliminated.

[0030]

As described above, according to the first aspect of the present invention, each side member on the left and right sides of the subframe is provided.
Extend in the front-rear direction and are separated from each other in the vertical direction
Composed of upper and lower side members
And between the middle part in the front-rear direction of the lower side member,
Integrally connected by a bracket extending in the vertical direction, since the upper arm and lower arm of the suspension in the upper end and the lower end of the bracket and supported respectively, reducing the number of parts and assembling steps by sharing the bracket for use and lower arm upper arm However , cost can be reduced . In addition , the subframe near the bracket
The rigidity of the arms (left and right side members) is extremely high
And at the same time increase the rigidity of the bracket itself,
Upper arm at the upper and lower ends of the rigid bracket
Load from the wheels by supporting the arm and lower arm.
Distributed to the upper and lower side members.
The suspension can be stopped, and the lateral rigidity and suspension
With fine camber stiffness is improved can increase the positional accuracy between the upper arm and lower arm, suspend
It is possible to make full use of the performance of the application.

[Brief description of the drawings]

FIG. 1 is a plan view of a subframe assembly.

FIG. 2 is a perspective view of a subframe assembly.

FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 1;

FIG. 5 is an enlarged view of a main part of FIG. 4;

FIG. 6 is a perspective view of a subframe.

FIG. 7 is an enlarged sectional view taken along line 7-7 of FIG. 6;

[Explanation of symbols]

 MF body frame RS rear suspension (suspension) SF subframe SM side member 3 upper side member 4 lower side member 5 first bracket (bracket) 11 upper arm 12 lower arm

Continuation of the front page (56) References JP-A-57-126762 (JP, A) JP-A-4-230421 (JP, A) JP-A-3-128778 (JP, A) JP-A-2-208172 (JP) JP-A-5-193519 (JP, A) JP-A-2-48487 (JP, U) JP-A 62-202474 (JP, U) JP-A 62-200074 (JP, U) JP 4-5184 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B62D 21/00 B62D 21/11 B62D 25/20

Claims (2)

(57) [Claims] 1. An automobile having a subframe (SF) mounted on a body frame (MF) and supporting left and right suspensions (RS) on the subframe (SF). Provided in each
The left and right side members (SM) in the front-rear direction.
Upper side members that extend and are vertically separated from each other
(3) and the lower side member (4)
Between the middle parts of the upper and lower side members (3, 4) in the front-rear direction
And communicating together by a bracket (5) extending in the vertical direction
Binding was characterized by the bracket upper arm of the suspension in the upper end and the lower end of (5) (RS) (11) and a lower arm (12) supported respectively, the sub-frame structure in a motor vehicle. 2. An upper part of said bracket (5) is provided on said upper part.
The sub-frame structure of a motor vehicle according to claim 1, wherein the sub-frame member extends above the side member (3) .