JP2000072029A - Sub-frame for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sub-frame for a vehicle that can reduce the weight of a vehicle body and the number of part items while ensuring center member support rigidity. SOLUTION: This sub-frame 10 supported by a body frame provided with lateral side members extended in the longitudinal direction of a body, and a front cross member laid between the front ends of the side members, is composed of first and second cross pipes 11, 12 laid between the rear ends of the lateral side members and extended in the cross direction of a vehicle, and a center member 13 laid between the first and second cross pipes 11, 12 and the front cross member and extended in the longitudinal direction of the body. A support bracket 27 (rear end part) of the center member 13 is connected to a support plate 38 jointed being laid between the first and second cross pipes 11, 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle subframe supported by a vehicle body frame.

[0002]

2. Description of the Related Art In an automobile, an engine, suspension, steering, or the like may be supported by a body frame via a subframe. As such a sub-frame, for example, as shown in FIG. 11, there is a sub-frame having a structure in which a center member 81 extending in the vehicle longitudinal direction is connected to a suspension member 80 extending in the vehicle width direction (for example, Japanese Utility Model Laid-Open No. 5-26745). No.).

The suspension member 80 is formed by joining a sheet metal lower member 80a and an upper member 80b in a middle state, and a rear end portion 81a of the center member 81 has elastic members 82, 82 on the lower surface of the lower member 80a.
Are fixed by bolts 83, 83.

Since the engine is mounted on the center member 81 via the cylindrical bushes 84, 84, it is necessary to increase the support rigidity of the center member 81. Therefore, conventionally, as shown in FIG. 12, there is a case where the cross section of the suspension member 80 is not collapsed by interposing a collar 90 or a reinforcement (not shown) between the lower member 80a and the upper member 80a. is there.

[0005]

However, the structure in which a collar or reinforcement is added to the suspension member to secure the supporting rigidity as in the above-mentioned conventional art has a problem that the number of parts and the weight increase.

In the above-mentioned conventional suspension member, since the upper member and the lower member are joined in the middle, the rigidity of the entire suspension member against the load in the vehicle width direction is sufficiently ensured to support the center member. It is necessary to increase the plate thickness of the suspension member or to add a reinforcing member in order to ensure the above, which also causes a problem that the weight increases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described conventional circumstances, and provides a vehicle sub-frame capable of reducing the weight of a vehicle body and reducing the number of parts while securing support rigidity of a center member. It is intended to provide.

[0008]

According to the first aspect of the present invention, there is provided a vehicle body frame having left and right side members extending in the front-rear direction of a vehicle body and a front cross member provided between front ends of the side members. And a first and second cross pipes extending between the rear ends of the left and right side members and extending in the vehicle width direction. And a center member that extends between the front cross member and the front cross member and extends in the front-rear direction of the vehicle body. The front cross member is connected to the front cross member while being connected.

According to a second aspect of the present invention, in the first aspect, an attachment seat for attaching a steering gear box to the support plate is integrally formed.

[0010]

According to the vehicle subframe of the present invention, the first and second cross pipes are erected between the left and right side members, and the first and second cross pipes are supported by a support plate. Since the rear end portion of the center member is connected to the support plate, the vehicle width can be reduced without increasing the plate thickness or adding a reinforcing member as in a conventional middle suspension member. This has the effect of securing rigidity against a load in the direction, reducing the weight as compared with conventional ones, and also eliminating the need for conventional collars and reinforcements, and has the effect of reducing the number of parts.

Further, the support plate can be arranged by effectively utilizing the empty space between the first and second cross pipes, and the space efficiency can be improved.

According to the second aspect of the present invention, since the steering gear box mounting seat is formed integrally with the support plate, the steering gear box can be supported by the first and second cross pipes having high rigidity. There is an effect that the support rigidity can be improved and the number of parts can be reduced by the amount that the gear box support bracket is not required.

[0013]

Embodiments of the present invention will be described below with reference to the accompanying drawings. 1 to 10 are views for explaining a subframe of an automobile according to one embodiment of the present invention. FIG. 1 is a schematic view of a body frame of the automobile as viewed from the side, and FIGS. FIG. 5 is a cross-sectional view of a body mounting pipe portion of the sub-frame, FIG. 6 is a cross-sectional view of a front cross member connecting portion of a center member, and FIG. 7 is a cross-sectional view of a cross pipe connecting portion of a center member. 8 to 10 are a perspective view, a sectional plan view, and a sectional front view of the center member, respectively.

In FIG. 1, reference numeral 1 denotes a vehicle body frame constituting a front portion of a vehicle body of an automobile. A front bumper 1a extending in a vehicle width direction is disposed in front of the vehicle body frame 1, and a left upper side of the front bumper 1a is provided. On the right side, a headlight 1a is provided. Also, on the left of the body frame 1,
A front wheel 1c is provided on the right side, and a hood 1d for opening and closing the engine room is provided above.

In the vehicle body frame 1, a front cross member 3 extending in the vehicle width direction is joined between the front ends of left and right side members 2 and 2 extending in the vehicle front-rear direction. It has a schematic structure in which extended rear cross members 4 are connected. The side member 2 and the front cross member 3 are formed in a rectangular closed cross section.

The left and right side members 2 extend obliquely downward from the rear end of a linear portion 2a extending substantially linearly.
The rear cross member 4 extends substantially linearly rearward following the lower end of the rear cross member 4b. A rear member 6 extending obliquely upward is connected to the rear end of the linear portion 2a of the side member 2, and the rear member 6 is connected to a front pillar (not shown).

A sub-frame 10 is provided below the body frame 1. The sub-frame 10 is disposed between the rear ends of the straight portions 2a of the left and right side members 2 and 2 and extends in the vehicle width direction.
1 and 12 and a center member 13 disposed between the first and second cross pipes 11 and 12 and the front cross member 3 and extending in the vehicle longitudinal direction. The first and second cross pipes 11 and 12 are made of a steel pipe having a substantially circular cross section.

The second cross pipe 12 has a diameter slightly larger than that of the first cross pipe 11. The second cross pipe 12 has a central portion 12b extending substantially linearly when viewed from the rear of the vehicle body, and a slightly lower portion following both ends of the central portion 12b. After being bent so as to incline, the central portion 12b and straight portions 12a, 12a extending substantially in parallel.

The first cross pipe 11 is disposed at a predetermined gap in front of the second cross pipe 12, and has a central portion 11b extending in parallel with the central portion 12b in plan view.
The central portion 11b has a generally bow shape including inclined portions 11a, 11a which extend from both ends of the central portion 11b and extend obliquely outward and forward.

Left and right symmetric suspension brackets 1 are provided at both ends of the first and second cross pipes 11 and 12, respectively.
4, 14 are provided. The suspension bracket 14 has a flange 1 formed by bending an upper bracket 15 and a lower bracket 16 made of sheet metal around the periphery of both.
5a and 16a are joined together by welding.
Has a middle closed cross section. The upper,
Reinforcement beads 15b, 16b extending along the outer circumference are formed on the lower brackets 15, 16.

The rear end of the suspension bracket 14 is connected to the rear cross member 4 via a bolt 17 inserted into a vehicle body mounting hole 14a formed at the rear end. The suspension bracket 14
An arm mounting hole 14b is formed in the outer portion of
A rear arm of a suspension arm (not shown) that supports the front wheel 1c is attached to the arm attachment hole 14b via a bolt.

At the front end of the left and right suspension brackets 14, an arm mounting bracket 18 is provided.
1 is welded to the tip. Thus, the left and right arm mounting brackets 18 are integrally connected by the first cross pipe 11. A front arm of the suspension arm is mounted on the arm mounting bracket 18 via an elastic bush (not shown).

A straight portion 12a of the second cross pipe 12 is inserted into a rear portion of the suspension bracket 14, and the straight portion 12a is welded to the suspension bracket 14 through welding holes 15d and 16d. The upper bracket 1 of the suspension bracket 14
5 and lower bracket 16 have semicircular recesses 15c, 1
6c is recessed, and the linear portion 12a is inserted and clamped in a circular hole formed by the recesses 15c and 16c.
And are welded.

An inclined portion 11a of the first cross pipe 11 is inserted into the front end of the suspension bracket 14, and the inclined portion 11a is welded through a welding hole 15g or the like. A cutout 15e is formed at the front end of the upper bracket 15 along the upper surface of the slope 11a, and a bulge 15f is formed at the front end of the cutout 15e to cover the tip of the slope 11a. Have been. The inclined portion 11a is inserted and clamped between the notch portion 15e, the bulging portion 15f, and the lower bracket 16, and is welded.

Both inclined portions 11 of the first cross pipe 11
a is formed with a through hole 11c penetrating the same in a direction perpendicular to the axis, and the peripheral portions of the through hole 11c of the both inclined portions 11a are formed so as to swell slightly upward. A similar through hole 16e is formed in a portion of the lower bracket 16 facing the through hole 11c.

A lower end base portion 20a of a steel pipe pipe 20 is inserted into each of the through holes 11c and 16e. The base portion 20a is integrally welded to the inclined portion 11a and the lower bracket 16. This mounting pipe 2
A cylindrical mounting member 21 is welded to the outer end portion 20b which extends outwardly while curving outwardly of the vehicle body with its axis line extending vertically. It is bolted and fixed to the wall 2a with a rubber member 22 interposed (see FIG. 5).

The center member 13 is connected to an engine support bracket 26 erected substantially vertically at the rear of a cylindrical center member main body 25 having a rectangular cross section, and is attached to the rear end of the center member main body 25 in the vehicle width direction. Is connected to a support bracket 27 extending to the front.

The center member main body 25 is formed by bending an inclined portion 25b which rises forward at the front end of a linear portion 25a extending substantially linearly in the front-rear direction, and has a substantially trapezoidal shape in front view at the front end of the inclined portion 25b. The mounting portion 25c is formed, and a flange portion 25d protruding in the vehicle width direction is formed integrally with a lower end edge of the mounting portion 25c. Fitting holes 25e are formed in the left and right flange portions 25d. Although not shown, the mount portion 25c of the center member main body 25 is slightly offset in the vehicle width direction from the axis of the linear portion 25a when viewed from above.

A cylindrical bush 28 is connected to the upper surface of the mount 25c. The cylindrical bush 28 is formed by interposing a rubber member 28b on the axis of the outer cylinder 28a.
In this structure, the outer cylinder 28a is welded to the mount 25c.

The engine support bracket 26 has a U-shaped cross section that opens forward, and the lower end 26a of the support bracket 26 is located on the left side of the center member main body 25.
Welded to the right side wall. This support bracket 26
A cylindrical bush 29 having the same structure as described above is disposed on the upper end 26b of the cylindrical bush 29, and an inner cylinder 29c of the cylindrical bush 29 is fastened and fixed by bolts 30.

An engine (not shown) is elastically supported through the front and rear cylindrical bushes 28 and 29 of the center member 13. The engine has a cylindrical bush 3 supported at the rear end of the side member 2 via a bracket 35.
6 are elastically supported. In this manner, the engine is supported at the center of gravity by the cylindrical bushes 28 and 29 of the center member 13 and is inertially supported by the cylindrical bush 36 of the side member 2. The engine is a horizontal engine mounted with the crankshaft 32 oriented in the vehicle width direction (see FIG. 1).

The support bracket 27 has a downward U-shape as viewed in cross section, and the center of the support bracket 27 is welded to the upper wall and the left and right side walls of the center member main body 25. At both ends of the support bracket 27, fitting holes 27a, 27
a is formed.

A thick support plate 38 is provided between the first and second cross pipes 11 and 12, and a front edge and a rear edge of the support plate 38 are respectively connected to the first cross pipe 11.
Is welded to the rear wall and the front wall of the second cross pipe 12. Bolt holes 38a, 38a are formed at both ends of the support plate 38.

Further, between the first and second cross pipes 11 and 12 on the left and right sides of the support plate 38, steering gear box support brackets 39 are bridged and welded. The support bracket 39 is a sheet-metal box, and a steering gear box (not shown) extending in the vehicle width direction is fixed to a front mounting seat 39a of the support bracket 39 by a bolt via a clamp member.

The left and right flange portions 25d at the front end of the center member 13 are elastically supported on the upper surface of the front cross member 3. More specifically, a rubber bush 40 is fitted into the fitting hole 25e of each flange portion 25d, a bolt 41 is inserted into a shaft center of the rubber bush 40 via a washer 42, and the bolt 41 is connected to the front cross member 3 by a screw. It is elastically connected to the upper wall by tightening.

The support bracket 27 of the center member 13 is elastically supported on the lower surface of the support plate 38. More specifically, similarly to the above, the rubber bush 40 inserted into the fitting hole 27a of the support bracket 27 is elastically connected to the support plate 38 by bolts 41.

The center member main body 25 is a rectangular cylindrical body formed by bending a rectangular flat plate into a rectangular cross section so that both edges along the longitudinal direction face each other, and overlapping the facing edges. In this case, the overlapping portion is spot-welded.
In the overlapping portion, concave portions 45a and convex portions 45b are formed alternately and in opposition to each other so as to form a waveform at a predetermined pitch in the longitudinal direction thereof. An opening 46 facing the center member main body 25 is formed.

The left and right convex portions 45b are spot-welded to each other by a spot gun inserted from the opening 46. The pitch P of the projections 45b is set so as to induce axial deformation of the center member main body 25 at the time of a frontal collision.

Lightening holes 47 are formed in the upper wall of the center member main body 25 at intervals so as to reduce the weight of the center member main body 25 and to reduce compression during frontal collision. It has a function to induce deformation.

Next, the operation and effect of this embodiment will be described. In the present embodiment, the sub-frame 10 includes first and second cross pipes 11 and 12 made of steel pipes extending in the vehicle width direction.
Since it is composed of the suspension brackets 14 connected to both ends of the first and second cross pipes 11 and 12,
By the first and second cross pipes 11 and 12, the rigidity against the load in the vehicle width direction can be improved without increasing the plate thickness or adding a reinforcing member as in the conventional middle suspension member. The weight can be reduced as compared with the conventional one.

The suspension bracket 14 is formed by welding the upper bracket 15 and the lower bracket 16 in the middle so as to form a closed cross section, and the first cross pipe is provided between the upper bracket 15 and the lower bracket 16. 11 and the second cross pipe 12
Welded by sandwiching the straight portion 12a of
2a and the inclined portion 11a are sandwiched by the entire suspension bracket 14 having a closed cross section, so that the strength and rigidity against loads in the vehicle vertical direction and the front-back direction can be improved.

Since both ends of the cross pipes 11 and 12 are sandwiched between the upper bracket 15 and the lower bracket 16, the degree of freedom in the shape of the ends of the cross pipes 11 and 12 can be improved. Thereby, the first cross pipe 1
The first and second sections are also formed when both ends of the first section are bent forward and outward.
The cross pipes 11 and 12 can be easily assembled. By the way, in the structure in which each cross pipe is inserted into the suspension bracket afterwards, both ends need to be formed in a straight line, and the degree of freedom in shape is restricted.

Since the sub-frame 10 has a structure including the first and second cross pipes 11 and 12 and the left and right suspension brackets 14 and 14, the first and second cross pipes 11 and 12 are provided.
By forming the central portions 11b and 12b of the cross pipes 11 and 12 into shapes corresponding to, for example, 2WD vehicles and 4WD vehicles having different drive systems, the suspension bracket 14 can be shared between 2WD vehicles and 4WD vehicles, and the cost of parts can be reduced. it can.

In this embodiment, the first cross pipe 1
Since the suspension arm mounting brackets 18 are welded to both ends of the suspension arm 1, the input from the suspension arm can be directly received by the high-rigidity cross pipe 11, thereby improving the support rigidity of the suspension arm and eliminating the need for a reinforcing member. The weight can be reduced as much as possible.

In this embodiment, the first cross pipe 1
A through hole 11c extending in a direction perpendicular to the axis is formed in the inclined portion 11a.
The base pipe 20a is inserted and fixed, and the outer end 20b of the mounting pipe 20 is connected to the side member 2. Therefore, the vehicle body mounting pipe 20 can be integrally connected to the cross pipe 11 having high rigidity against lateral force in the vehicle width direction. It is possible to improve both the rigidity against the lateral force and the rigidity against the point of application to the vehicle body, thereby improving the steering stability and reducing the noise generated from the vehicle body frame.

Since the base 20a of the vehicle body mounting pipe 20 is welded to the first cross pipe 11 and to the lower bracket 16, the rigidity against the lateral force and the rigidity at the vehicle body application point can be further increased.

According to the present embodiment, a support plate 38 is erected and welded between the first and second cross members 11 and 12, and the rear end support bracket 27 of the center member 13 is attached to the support plate 38. Since the front end 25 d of the center member 13 is elastically connected to the front cross member 3 via the rubber bush 40, the front end 25 d of the center member 13 is elastically connected to the front cross member 3. The plate 38 can be supported, and the support rigidity of the center member 13 can be improved accordingly. As a result, it is not necessary to use a collar or reinforcement for securing rigidity as in the related art, and it is possible to reduce the number of parts and the weight.

The first and second cross pipes 11, 1
The support plate 38 can be disposed by effectively utilizing the empty space between the two, and the efficiency of a narrow space can be improved.

In the above embodiment, the case where the support plate 38 is installed on the first and second cross pipes 11 and 12 has been described. However, in the present invention, the steering gear box is mounted on both ends of the support plate 38. The seat may be integrally formed. In this case, the supporting stiffness of the steering gear box can be improved by the first and second cross pipes 11 and 12 having high rigidity, and the number of parts can be reduced as much as the gear box mounting bracket is not required.

In the present embodiment, the center member main body 25 of the center member 13 is a rectangular cylinder formed by bending a flat plate, and corrugated concave portions 45a are formed at both edges of the overlapping portion of the rectangular cylinder extending in the axial direction. And the projections 45b are alternately formed, and the overlapped portions of the projections 45b are spot-welded, so that the spot gun is inserted using the openings 46 formed by the recesses 45a. 45b can be spot-welded, and the cost can be reduced as compared with the conventional case of performing arc welding over the entire length of the center member. Further, the electrodeposition liquid in the coating step can be discharged using the opening 46.

Further, since the above-described flat plate is bent to form a rectangular cylinder having a closed cross section, the rigidity of the center member main body 25 as a whole can be ensured, and the conventional reinforcement can be dispensed with, thereby reducing the cost. .

Further, by appropriately setting the pitch P of the convex portions 45b, a crash mode for inducing axial deformation of the center member 13 at the time of a frontal collision can be provided, and a collision energy absorbing function can be obtained. .

[Brief description of the drawings]

FIG. 1 is a schematic view of a vehicle body frame viewed from a side of an automobile according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a sub-frame supported by the vehicle body frame.

FIG. 3 is an exploded perspective view around a suspension bracket of the subframe.

FIG. 4 is a side view of the sub-frame.

FIG. 5 is a cross-sectional view of a body mounting pipe portion of the sub-frame.

FIG. 6 is a sectional view of a front end connecting portion of a center member of the sub-frame.

FIG. 7 is a sectional view of a rear end connecting portion of the center member.

FIG. 8 is a perspective view of the center member.

FIG. 9 is a sectional plan view of the center member.

FIG. 10 is a transverse sectional view of the center member (a sectional view taken along line XX of FIG. 9).

FIG. 11 is an exploded perspective view of a conventional general subframe.

FIG. 12 is a cross-sectional view of a conventional suspension member connecting portion.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Body frame 2 Side member 3 Front cross member 10 Subframe 11 1st cross pipe 12 2nd cross pipe 13 Center member 27 Support bracket (center member rear end part) 38 Support plate

Claims (2)

[Claims] 1. A subframe for a vehicle supported by a vehicle body frame having left and right side members extending in a vehicle front-rear direction and a front cross member provided between front ends of the side members. A first and second cross pipes extending between the rear ends of the left and right side members and extending in the vehicle width direction, and being installed between the first and second cross pipes and the front cross member. A center member extending in the front-rear direction of the vehicle body, and a rear end of the center member is joined to a support plate that is bridged and joined between the first and second cross pipes,
A vehicle sub-frame having a front end coupled to the front cross member. 2. The sub-frame for a vehicle according to claim 1, wherein a mounting seat for mounting a steering gear box is integrally formed with the support plate.