JP3487213B2 - Vehicle subframe structure - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a subframe structure for a vehicle, and more particularly to a subframe structure for a vehicle which is joined and fixed to a member constituting a lower wall of a vehicle body and which supports a suspension device and a part of a driving force transmission system.

[0002]

2. Description of the Related Art In a vehicle, for example, an automobile, wheels are attached to respective front, rear, left and right sides of the vehicle body through suspension devices, and a rotational force is transmitted to each of these wheels through a drive force transmission system arranged at a lower portion of the vehicle body. It is transmitted. As described above, a suspension device, a driving force transmission system, and the like are provided below the vehicle body. These are a floor material that is a lower wall component of the vehicle body, and are welded to the floor material and extend in the front-rear direction of the vehicle body. Further, the pair of left and right side members, the side members are connected to each other, and are also connected to a straight cross member welded to the floor member via various brackets and subframes. For this reason, it is necessary for the lower wall constituent member of the vehicle body to have sufficient strength for supporting the suspension device, the driving force transmission system, the wheels, and the like with good durability and accuracy.

By the way, a sub-frame which connects left and right ends to a pair of left and right side members provided on the lower part of the vehicle body, and particularly, the left and right end connecting parts connect the left and right inclined parts and the lower ends of these left and right inclined parts. It is known that a straight central portion is continuously formed in a downward convex shape. In this subframe structure, the left and right end joints and the bent portions at the lower ends of the left and right inclined portions are vertically offset by a predetermined amount, and the base ends of the lower arms, which are the left and right suspension arms, are made of rubber at each bent portion. It is pin-connected through the bush. Here, a coil spring is mounted between the spring receiving portion and the central portion of the lower arm. In this case, the rocking ends of the left and right lower arms pivotally support the wheels via knuckles, and the road surface reaction force from the wheels is input to the left and right spring bearings via the lower arms and coil springs. It is distributed and supported on the left and right side member sides.

An example of such a subframe structure is disclosed in Japanese Patent Laid-Open No. 7-315245. here,
Of the pair of front and rear cross members that weld the left and right ends to the pair of left and right side members, the front cross member is convex upward,
The rear cross members are each formed to have a downward convex shape, and even if the pair of left and right side members are both elastically deformed toward the center of the vehicle body, the displacement amounts of the front and rear cross members are equal to each other, and the wheel toe It is designed so that there is no deviation in the corners. The rear cross member used here has a vertical bracket projecting in an area secured above the center thereof, and a differential housing is attached to the vertical bracket.

[0005]

By the way, in the subframe structure in which the spring receiving portion and the bent portion are vertically offset as described above, when the spring receiving portions at the upper ends of the pair of left and right inclined portions receive a large input load. The problem that the spring receiving portion at the upper end of the inclined portion is deformed with each side member toward the center of the vehicle body with each bending portion side as a fulcrum, causing a deviation in the aligned state of the wheels and reducing the durability of the cross member itself. There is. Especially in off-road vehicles, the vertical stroke of the wheels is set to be large, so that the coil spring is long, the vertical offset amount between the spring receiving portion and the bending portion increases, and the inclined portion side uses each bending portion as a fulcrum. This is a problem because it tends to deform toward the center and causes a large deviation in the alignment of the wheels.

In the vehicle subframe structure disclosed in Japanese Patent Laid-Open No. 7-315245, displacement of the front and rear cross members is allowed. When only one of the front and rear cross members is used, the cross member is Further, both the side members are easily elastically deformed toward the center of the vehicle body, and the wheel alignment state is likely to be displaced. The lower edge of the vertical bracket to which the differential housing is attached is welded to the center of the cross member here. However, if a spring bearing is formed on the cross member here, in this case, the spring bearing is When a road surface reaction force is applied, the cross member is likely to be deformed toward the center of the vehicle body with the joint end portion of the vertical bracket as a fulcrum, which may cause a misalignment of the wheel alignment or a decrease in durability. An object of the present invention is to suppress the deformation of the inclined portion formed with the spring receiving portion on the upper end side toward the center of the vehicle body, properly maintain the aligned state of the wheels, ensure the steering stability, and prevent the deterioration of durability. It is to provide a subframe structure of a vehicle capable of.

[0007]

In order to achieve the above-mentioned object, in the invention of claim 1, it is extended in the longitudinal direction of the vehicle.
It is joined and fixed to a pair of left and right side members,
A dish-shaped left and right that receives the road reaction force via the coil spring
A pair of spring bearings and below the center of the vehicle from both spring bearings
Of a pair of left and right inclined parts extending toward
Left side formed on the lower end and connected to the suspension arm
A pair of right bent parts and extended from both bent parts toward the center of the vehicle body.
A vehicle-width-direction extending member having a straight central portion, and the above springs
One end of the vehicle width direction extending member on the vehicle body center side from the receiving part
Join and fix the other end to each side member or each side member.
Left and right tightened to the cross members that connect the members to each other
A pair of front-rear direction extending members, and the vehicle width direction extending member
End greens are in contact with both of the above sloped parts and the straight center part.
Fixed together, the rear end of the above vehicle differential device
The vertical plate part to which is attached and the front edge of the vertical plate part above
Has a front extension part that bends and extends to the left and right of the vertical plate part
The side edge and the left and right side edges of the front extension part extend in the front-rear direction.
It is characterized by comprising a reinforcing plate member joined and fixed to a member.
And

Here, since the edge of the reinforcing plate member is joined and fixed to both the inclined portions formed on the upper end side of the spring receiving portion and the straight center portion, both inclined portions formed on the upper end side of the spring receiving portion are bent respectively. Even if you try to deform to the center side of the car body with the part side as a fulcrum,
The reinforcing plate member here functions as a tension member, and it is possible to reliably prevent the displacement of the two inclined portions having the spring receiving portion formed on the upper end side approaching each other. Therefore, it is possible to suppress the deformation of both the inclined portions formed with the spring receiving portion on the upper end side toward the center of the vehicle body, properly maintain the aligned state of the wheels, ensure the steering stability, and prevent the deterioration of the durability. Moreover, the reinforcing plate material can reliably support the differential device of the vehicle, and the parts can be shared. Further, since the rigidity of the cross member is enhanced by the reinforcing plate material, it is possible to reduce the generation of road noise due to the resonance of the cross member.

Preferably, a pair of left and right spring receiving portions may be fastened and coupled to the pair of left and right side members. In this case, a suspension device or a part of the power transmission mechanism can be temporarily assembled to the cross member to form a sub-assembly, and the sub-assembled cross member assembly can be mounted on the vehicle body, and workability during outfitting can be improved.

According to a second aspect of the present invention, in the subframe structure for a vehicle according to the first aspect, the left and right extending in the front-rear direction.
The member is the vehicle body of the left and right spring bearings whose outer side walls are
It is characterized by being welded to the central side wall. others
Therefore, the left and right spring bearings are connected to the vertical plate through the longitudinally extending members.
In the state of being joined and fixed to the left and right side edges, the reinforcing plate member serves as a tension member to prevent the displacement of the spring receiving portion and the inclined portion approaching each other .

[0011]

1 and 2 show a lower vehicle body structure of an automobile including a vehicle subframe structure to which the present invention is applied. In this lower vehicle body structure, mounting portions J1 and J2 are formed on a lower wall constituent member described later, and a chassis member Ms as a subframe is fastened and fixed to the mounting portion. The lower vehicle body structure has the chassis member Ms and other members. A rear suspension device S that attaches the rear wheels W in a properly aligned state to the lower wall constituent member and a part of a driving force transmission system PT that transmits the driving force to the rear wheels W are mounted.

As shown in FIG. 2, the lower wall constituting member has its upper surface joined to the floor material 3 facing the passenger compartment CR and the lower surface of the floor material 3, and as shown in FIG. It is composed of a pair of left and right long side members 4 and a cross member 5 integrally joined between the side members 4 and welded to the floor member 3. The cross member 5 is welded to a relatively front side (upper side in FIG. 1) of the pair of left and right side members 4, and front left and right front mounting portions J1 are formed on the vehicle body center side by a predetermined amount from the left and right ends of the cross member 5. Moreover, rear left and right rear mounting portions J2 are formed on the relatively rear side (lower side in FIG. 1) of the pair of left and right side members 4, respectively. Each of the mounting portions J1 and J2 is provided with a bolt hole (not shown) through which a tightening bolt (not shown) is vertically inserted. The opposing parts on the Ms side are tightened and coupled.

As shown in FIG. 3, the chassis member Ms forming the main part of the vehicle sub-frame structure to which the present invention is applied is a bending cross member 1 extending in the vehicle width direction Y and a bending cross member 1 of the bending cross member 1. It is composed of a pair of left and right extending members 7 extending in the front-rear direction X having their rear ends welded. As shown in FIG. 2, the bent cross member 1 includes a vehicle width direction extending member 1A and a reinforcing plate member 8 having end edges joined and fixed to the vehicle width direction extending member. Here, the vehicle width direction extending member 1A includes a pair of dish-shaped left and right spring receiving portions 101 joined and fixed to both side members 4, and left and right extending from each spring receiving portion 101 toward the lower side of the center of the vehicle body. A pair of inclined portions 102, a pair of left and right bent portions 103 formed at the lower ends of the both inclined portions, and a straight central portion 104 extending from the both bent portions 103 toward the center of the vehicle body are provided on which a reinforcing plate material is provided. 8 is welded.

As shown in FIG. 4 (a), the vehicle width direction extending member 1A has a closed cross-sectional shape in which an upper plate member 1a having a hat-shaped cross section and a lower plate member 1b having a flat plate shape are overlapped with each other and their peripheral edges are welded to each other. Is formed. The spring receiving portion 101 of the vehicle width direction extending member 1A has an upper plate member 1a and a lower plate member 1a.
Both ends of b are formed into dish-shaped end portions, and these are stacked on top of each other to form a dish-shaped spring receiving portion 101. A bolt hole h is formed in the central portion of the spring receiving portion 101, the same portion is overlapped with each rear mounting portion J2 of the left and right side members 4, and is fixed by tightening with a tightening bolt (not shown). The pair of left and right bent portions 103 has a downward recess (not shown) formed below the corps surface portion formed by the upper plate member 1a and the lower plate member 1b. The base ends are connected.

The reinforcing plate member 8 is a sheet metal member extending in the vehicle width direction Y, and is formed of a vertical plate portion 801 and a front extending portion 802 which is bent forward from an upper edge of the vertical plate portion 801 and extends. The left and right side edges of the vertical plate portion 801 are welded to the rear end of the front-back direction extending member 7, and the lower edge thereof is continuously welded across the pair of left and right inclined portions 102, the bent portion 103, and the straight central portion 104. . The front extension 8
The left and right side edges of 02 are welded to the center side wall of the vehicle body in the vicinity of the rear end of the front-rear direction extending member 7, thereby strengthening the rigidity of the reinforcing plate member 8 itself. The rear end of the front-rear extension member 7 is welded to the reinforcing plate member 8 at the center side wall of the vehicle body and to the left and right vehicle outer side walls of the left and right spring receiving portions 101 at the vehicle body center side sidewalls. 101 is in a state of being joined and fixed to the left and right side edges of the vertical plate portion 801 via the front-back direction extending member 7.

The vertical plate portion 801 has a pair of left and right differential mounting holes 1 in the center thereof at a predetermined distance in the vehicle width direction Y.
2 (see FIG. 3). As shown in FIG. 4A, the differential mounting hole 12 supports the outer cylinder 13 by press fitting, and the outer cylinder 13 is vulcanized and bonded to the rubber bush 15 that supports the inner cylinder 14. A differential housing 16 of the driving force transmission system PT is provided in front of the inner cylinder 14. Same differential housing 1
A boss portion 161 is projectingly provided on the rear wall of 6, and a bolt 17 inserted through the inner cylinder 14 is screwed into a screw hole formed in the boss portion 161, whereby the rear end of the differential housing 16 is attached to the vertical plate portion 801. It is installed.

A pair of left and right front-rear extension members 7 extending in the front-rear direction X and arranged in parallel with each other are welded at their rear ends to the side walls of the spring bearing 101 of the vehicle-width-direction extension member 1A on the center side of the vehicle body. The front end has a pair of left and right front mounting portions J1 on the cross member 5.
It is fixed in place. Here, since the intermediate portions of the front-rear extension members 7 are joined to each other by the pipe member 18, not only the rigidity of the pair of left-right front-rear extension members 7 themselves but also the rigidity of the entire chassis member Ms is sufficiently strengthened. . A pair of left and right holding brackets 19 extending downward are welded near the left and right ends of the pipe member 18, respectively. As shown in FIG. 1, each pair of left and right holding brackets 19 is a pipe member 1.
Left and right boss portions 2 of the hollow bar member 20 arranged in parallel below 8
01 is pin-coupled via a rubber bush (not shown). The front end of the differential housing 16 is disposed below the central portions of the pipe member 18 and the hollow bar member 20,
A pair of left and right connecting bosses 162 (see FIG.
(Only one of which is shown in FIG. The connecting boss 162 has its upper surface superposed on the lower surface of the hollow bar member 20, and a bolt 22 is vertically penetrated through the both, and is fastened and coupled to each other by the bolt and the nut.

The rear suspension device S connects the rear wheel W, which is a non-steered wheel, to the lower part of the vehicle body while allowing the rear wheel W to be vertically aligned while allowing the rear wheel W to be properly aligned, and includes a link mechanism s1 and a shock absorbing mechanism s2. The link mechanism s1 includes a knuckle 25 that pivotally supports the rear wheel W, and the knuckle 23 side is connected to the vehicle body side using four suspension arms so that the knuckle 23 side can be moved up and down and can be moved up and down. That is, the lower arm 11 includes the knuckle 25 and the bent portion 1 of the vehicle width direction extending member 1A.
03 is rotatably pin-coupled to each other via rubber bushes (not shown), the swing end of the upper arm 26 is coupled to the knuckle 25 via a ball joint (not shown), and the base end thereof is a front-rear arm of the front-back direction extending member 7. The toe control arm 27 is rotatably pin-coupled to the brackets 23 and 24 via rubber bushes (not shown).
Is rotatably pin-coupled to the knuckle 25 and the downward bracket 28 on the front-rear direction extending member 7 side through rubber bushes not shown, and the trailing arm 29 is a trailing arm of the knuckle 25 and the trailing of the side member 4. The arm bracket 30 is rotatably pin-coupled to the arm bracket 30 via rubber bushes (not shown).

The shock absorbing mechanism s2 absorbs and reduces a reaction force variation component from the road surface e input from the rear wheel W, and is composed of a coil spring 31 and a shock absorber 32. The left and right coil springs 13 are bent cross members 1
The spring receiving portion 101 formed on the lower arm 11 and the lower spring receiving portion 111 of the lower arm 11 are mounted while being compressed and urged. The pair of left and right shock absorbers 32 has a lower end pinned to a lower end mounting portion 112 provided inside the lower arm 11, and an upper end to a upper end mounting portion 34 provided on a side wall 33 on the vehicle body side via a cushioning member. To be done.

During production of a vehicle body equipped with the chassis member Ms including the bending cross member 1 as described above, the differential member 1 of the link member s1, the shock absorbing mechanism s2 and the driving force transmission system PT is attached to the chassis member Ms.
6 and the like are tentatively assembled into a chassis member assembly and then supplied to the production line. Then, each mounting portion J1,
The chassis member Ms is attached to the lower wall constituting member on which J2 is formed.
The four tightening points are opposed to each other, and the facing portions are sequentially tightened and coupled by tightening bolts (not shown). In this case, the work of assembling the sub-assembled chassis member Ms on the production line is extremely simplified, the work of assembling here can be easily performed, and the workability can be improved. Moreover, since the parts on the chassis member assembly side are accurately assembled in advance to the chassis member Ms, the assembly accuracy after outfitting can be easily ensured.

Further, in the vehicle body structure including the chassis member Ms described above, as shown in FIGS. 1 and 5, the spring bearing portion 101 is used.
And the bent portion 103 are vertically offset by a distance L. When the left and right spring bearing portions 101 receive an input load F, which is a large road surface reaction force, during running of an automobile having such a vehicle body structure, the inclined portion 102 formed with the spring bearing portions 101 on the upper end side is moved left and right. Together with the side member 4 of FIG. However, here, since the left and right side edges of the reinforcing plate member 8 are joined and fixed to both the inclined portions 102 formed with the spring receiving portion 101 on the upper end side, and the lower edge is joined and fixed to the straight central portion 104,
Even if the left and right inclined portions 102 side try to deform M toward the vehicle body center side, the reinforcing plate member 8 can exert a function of applying a reaction force R to both inclined portion 102 sides having the spring receiving portion 101 formed on the upper end side as a supporting member. Therefore, the deformation operation M toward the vehicle body center side where the spring receiving portions 101 approach each other can be reliably prevented.

In particular, the vehicle body structure including the chassis member Ms of FIG. 1 has a coil spring 31 so as to be suitable for an off-road vehicle.
Is long, the vertical displacement stroke of the rear wheel W is set to be relatively large, and the vertical offset amount L between the spring receiving portion 101 and the bent portion 103 is set to be relatively large. A spring receiving portion 101 as a strut member.
It is possible to reliably prevent the deformation operation M of the inclined portions 102 formed on the upper end side. Therefore, the left and right inclined portions 102 formed with the spring receiving portion 101 on the upper end side are prevented from being deformed toward the center of the vehicle body, the rear wheel W is properly maintained in the aligned state, the steering stability is secured, and the durability is improved. It is possible to prevent deterioration of sex. Further, the reinforcing plate material 8
Can reliably support the differential housing 16, and can also maintain the function of the differential housing 16 as a bracket, so that parts can be shared. Further, since the rigidity of the bending cross member 1 is enhanced by welding and reinforcing the reinforcing plate member 8, the resonance frequency of the chassis member Ms is adjusted to the low frequency side when resonance may occur. It is easy to do so, and the generation of road noise due to resonance can be reduced.

Further, the chassis member Ms shown in FIGS.
Is joined and fixed to both spring receiving portions 101 at the rear end of the front-back direction extending member 7, and at the portion thereof is joined and fixed to the left and right side edges of the reinforcing plate member 8, whereby the rear end of the front-back direction extending member 7 is fixed. The left and right ends of the reinforcing plate member 8 indirectly apply a reaction force R to the spring receiving portions 101 via the springs, thereby preventing the deformation operation M in which the spring receiving portions 101 approach each other. On the other hand, the front-rear direction extending member 7 may be eliminated, and the left and right ends of the reinforcing plate member 8 may directly apply the reaction force R to the side walls of the spring receiving portions 101 on the vehicle body center side. Also, substantially the same operational effect as the chassis member Ms of FIG. 1 can be obtained. Further, the front-rear direction extending member 7 may be eliminated, and a main part of the rear suspension device S and the differential housing 16 may be mounted and supported by a chassis member (not shown) formed of a single bent cross member. In this case, substantially the same operational effects as the chassis member Ms in FIG. 1 can be obtained, and the device can be simplified.

In the above description, the lower body structure including the chassis member Ms is described as supporting the rear suspension device S, but instead of this, the present invention is applied to the lower body structure supporting the front suspension device and the front differential housing. The present invention can be applied, and in those cases, substantially the same operational effects as those of the vehicle subframe structure of FIG. 1 can be obtained. Although the above-described sub-frame structure is clamped and fixed to the mounting portions J1 and J2 on the side member side, a sub-frame structure (not shown) may be configured to be joined and fixed to the side member side by welding or the like. Also, the same effect as the subframe structure of the vehicle shown in FIG. 1 can be obtained.

[0025]

According to the first aspect of the present invention, since the edge of the reinforcing plate member is joined and fixed to the inclined portion formed with the spring receiving portion on the upper end side, the reinforcing plate member forms the spring receiving portion on the upper end side as a tension member. It is possible to reliably prevent the displacement of the two inclined parts approaching each other, and therefore, it is possible to suppress the deformation of the inclined parts formed by the left and right spring bearings on the upper end side toward the center of the vehicle body and to properly maintain the aligned state of the wheels. The steering stability can be ensured, the durability can be prevented from lowering, and the reinforcing plate material can surely support the differential device of the vehicle, so that the parts can be shared. Further, since the rigidity of the cross member is enhanced by the reinforcing plate material, it is possible to reduce the generation of road noise due to the resonance vibration of the cross member. Also, make sure that both spring bearings are
Join and fix one end of the extension member, and
Reinforcement by joining and fixing one end of the reinforcing plate material to one end
The plate member is a strut member, and the spring receiving part and the inclined part are
It is possible to prevent the displacement from approaching to the
State is maintained properly, steering stability is secured, and durability is reduced.
It can be prevented. In particular, the reinforcing plate is the right and left side edges of the front extension.
Is welded to the member extending in the front-rear direction, the rigidity of the reinforcing plate itself
The sex can be strengthened. In the invention of claim 2, the left and right spring receiving portions
Is fixed to the left and right side edges of the vertical plate through the longitudinally extending members.
In the fixed state, the reinforcing plate member serves as a tension member to prevent displacement of the spring receiving portion and the inclined portion approaching each other.

[Brief description of drawings]

FIG. 1 is a cutaway plan view of an essential part of a lower vehicle body having a vehicle subframe structure as an embodiment of the present invention.

FIG. 2 is a rear view of a notched main portion of a lower vehicle body having the subframe structure of the vehicle of FIG.

FIG. 3 is a perspective view of a chassis member used in a lower vehicle body having the subframe structure of the vehicle of FIG.

4 shows an essential part of a lower vehicle body having a subframe structure of the vehicle of FIG. 1, (a) is an enlarged sectional view taken along the line AA of FIG.
(B) is an enlarged cross-sectional view taken along the line BB of FIG. 1.

5 is a deformation explanatory view of the lower vehicle body having the sub-frame structure of the vehicle of FIG. 1 due to an input load.

[Explanation of symbols]

1 Bending cross member 1A Vehicle width direction extension member 101 Spring receiving part 102 slope 103 Bend 104 Straight center 4 side members 7 Front-rear extension member 8 Reinforcement plate material 11 Lower arm 16 differential housing 31 coil spring F input load (road reaction force) Ms chassis member (subframe) S rear suspension device X front-back direction Y vehicle width direction W rear wheel

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Claims (2)

(57) [Claims] 1. A pair of disc-shaped left and right spring bearing portions, which are joined and fixed to a pair of left and right side members extending in the front-rear direction of a vehicle and receive a road surface reaction force from a wheel via a coil spring. A pair of left and right inclined portions extending downward from the spring receiving portion toward the center of the vehicle body, a pair of left and right bent portions formed at the lower ends of the both inclined portions, to which suspension arms are connected, and the vehicle body extending from the both bent portions. center side in the vehicle width direction extending member having a Jikajo central portion which is extended in said vehicle width direction extending portion of the vehicle body center side than the respective spring receiving portions
One end is joined and fixed to the material and the other end is attached to each side member or the same.
Tighten the cross members that connect each side member to each other.
End greens are joined and fixed to the pair of right and left extending members which are combined, and the both inclined portions and the straight center portion of the vehicle width extending member, and the rear end of the differential device of the vehicle is attached. Vertical plate part
And a front extension that bends forward from the upper edge of the vertical plate portion and extends.
And the left and right side edges of the vertical plate portion and the left of the front extending portion.
A subframe structure for a vehicle, comprising a reinforcing plate member having a right side edge joined and fixed to each of the front-back direction extending members . 2. The subframe structure for a vehicle according to claim 1, wherein the left and right frontward and rearward extending members have their left and right vehicle outer side walls welded to the vehicle body center side sidewalls of the left and right spring bearing portions. Characteristic vehicle subframe structure.