JP2002308143A - Vehicle body base structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain both the reduction of the vibration transmission from an engine and the improvement in durability of an elastic member. SOLUTION: Both ends of a cross member 70 for supporting the engine 72 from under through a mount rubber 71 arranged along the vehicle lateral direction are connected to lateral brackets 66 for connecting the front end 64b of the arm 64 of a stabilizer 15 to side members 1 and 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lower body structure having an air spring between a chassis frame and an axle.

[0002]

2. Description of the Related Art In general, a front portion of an engine mounted on a vehicle such as a truck is supported from the side by side members disposed on both sides in the vehicle width direction along the longitudinal direction of the vehicle body. Further, an elastic member is interposed between the engine and the side member in order to reduce transmission of vibration from the engine to the side member.

[0003]

Here, it is preferable to use an elastic member having a low spring constant (soft) in order to reduce vibration transmission, and to use a high spring constant in order to increase durability. It is preferable to use a (hard) elastic member. An elastic member having a low spring constant in the direction of the force generated by the rotation of the crank is suitable for reducing the transmission of vibration when supporting the engine.

However, in a structure in which the front portion of the engine is supported from the side, the direction of the force acting on the elastic member due to the rotation of the crank and the direction of the force deforming the elastic member by the mass of the engine itself are both vertical. Becomes That is, the direction in which a low spring constant is desired to reduce vibration transmission is the same as the direction in which a high spring constant is desired to improve durability. For this reason, it was difficult to use an elastic member having a low spring constant from the viewpoint of durability.

[0005] Even if the elastic member has a low spring constant (soft), the durability can be improved by enlarging the mounting area.

However, in the structure in which the engine is supported by the side members, the mounting area is small, and as a result, an elastic member having a high spring constant has to be used, and it has been difficult to reduce the vibration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a vehicle body lower structure capable of reducing vibration transmission from an engine and improving durability of an elastic member. It is the purpose.

[0008]

In order to achieve the above object,
The vehicle body lower part structure according to the present invention includes a first and second chassis frame, an axle, first and second air springs, first and second air spring support portions, a stabilizer, a bracket, And a cross member. The first and second chassis frames extend in the vehicle longitudinal direction on both sides in the vehicle width direction. The axle extends below the first and second chassis frames in the vehicle width direction.
The first and second air springs are disposed between the first and second chassis frames and the axle. The first and second air spring support portions are provided on both sides of the axle in the vehicle width direction and support the first and second air springs from below. The stabilizer is substantially U-shaped having a torsion bar and an arm. The torsion bar is arranged along the vehicle width direction, and both ends thereof are rotatable with respect to the first and second air spring support portions. Are linked. The arms extend forward from the both ends of the torsion bar.
The bracket is connected to the respective front end of the arm and the first and second arms.
To the chassis frame. The cross member is arranged along the vehicle width direction, and both ends of the cross member are connected to the bracket. The cross member supports the engine from below through an elastic member.

In the above configuration, the engine is supported from below by the cross member via the elastic member. in this case,
The direction of the force acting on the elastic member due to the rotation of the crank is the vehicle width direction, and the direction of the force deforming the elastic member by the mass of the engine itself is the vertical direction. That is, the direction in which a low spring constant is desired to reduce vibration transmission and the direction in which a high spring constant is desired to improve durability are substantially orthogonal to each other. Therefore, the force applied to the elastic member is dispersed, and practically sufficient durability can be obtained even if an elastic member having a low spring constant is used.

Further, by using a cross member having an upper surface having a large area, the mounting area of the elastic member can be increased, and sufficient durability can be obtained even if an elastic member having a low spring constant is used. .

As described above, according to the above configuration, it is possible to achieve both reduction of vibration transmission from the engine and improvement of durability of the elastic member.

Further, in the structure using the air spring, a bracket for supporting the stabilizer required for obtaining the anti-roll effect is used for supporting the cross member, so that the parts can be shared. Can save space, reduce the number of parts, and simplify the structure.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing a lower body structure according to this embodiment, FIG. 2 is a plan view of the structure of FIG. 1, FIG. 3 is a side view of the structure of FIG. 1, and FIG. It is principal part sectional drawing along the width direction. In the following description, the front-rear direction is the front-rear direction of the vehicle body, and the left-right direction is the left-right direction in a state facing the front of the vehicle body.

As shown in FIGS. 1 to 3, a pair of left and right side members as first and second chassis frames extending in the front-rear direction of the vehicle on both left and right sides in the vehicle width direction are provided at the lower front portion of the vehicle body of the large vehicle. 1, 2 and a front axle 3 extending below the side members 1 and 2 along the vehicle width direction. Each of the side members 1 and 2 has a substantially U-shaped cross section arranged to open inward in the vehicle width direction, and includes a side wall 4 and upper and lower walls 5 and 6 extending from upper and lower ends thereof. The front axle 3 has a substantially I-shaped cross section. The front wheels 50 (shown in FIG. 3) are connected to both ends 7 of the front axle 3 projecting outward in the vehicle width direction from the side members 1 and 2 via knuckles (not shown).

On the upper wall 8 of the front axle 3 vertically below the left side member 1, a first air spring support portion is disposed substantially parallel to the side member 1 and extends from the front axle 3 in the vehicle longitudinal direction. A spring seat 9 is attached. The spring seat 9 is secured to the front axle 3 by bolts 12 and nuts 13 at an overlap portion 11 overlapping the front axle 3.
It is fastened and fixed. A rear end 14a of the torque rod 14 is rotatably connected to an upper front end of the spring seat 9, and a left end 65a of a torsion bar 65 of the stabilizer 15 is rotatably connected to the lower front end. The left end of the lateral rod 16 is rotatably connected to the rear end of the spring seat 9.

A spring seat 10 as an air spring support is also mounted on the upper wall 8 of the front axle 3 vertically below the right side member 2 similarly to the left side member. The right spring seat 10 is configured generally similarly to the left spring seat 9 except that it does not have a rear end connected to the lateral rod 16.

On both left and right sides, spring seats 9,
Air springs 17 and 18 are provided between the overlap portion 11 and the side members 1 and 2, respectively.

The air springs 17 and 18 include a top plate 19, a piston 20, and an air bellows 21. The piston 20 is fixed to the overlap portion 11 of the spring seats 9, 10 via an air spring support bracket (not shown) on the front axle 3 side. The air spring support bracket is fixed to the spring seat 9 by bolts 12 and nuts 13 for fixing the spring seats 9 and 10 to the front axle 3.
It is fastened and fixed. The top plate 19 is fastened and fixed to the side walls 4 of the side members 1 and 2. The air bellows 21 is formed of a substantially cylindrical flexible film having a substantially circular upper opening (not shown) and a lower opening (not shown). The upper opening and the lower opening of the air bellows 21 are fitted to the top plate 19 and the piston 20 in close contact with each other. In this state, the top plate 19, the piston 20, and the inner surface of the air bellows 21 define an air chamber (not shown). The air bellows 21 is a so-called self-sealing type in which the peripheral portions of the upper opening and the lower opening are fixed to the top plate 19 and the piston 20 in close contact with each other only by the air pressure in the air chamber. The air bellows 21 can be manually attached to and detached from the top plate 19 and the piston 20.

The piston 20 or the top plate 1
9 is provided with a supply / exhaust port (not shown) for supplying and exhausting air to and from the air chamber.

As described above, the spring seats 9, 1
0, the front end of the torque rod 14
4a is rotatably connected. A left end 65a and a right end 65b of a torsion bar 65 disposed along the vehicle width direction are rotatably connected to lower front ends of the spring seats 9, 10, respectively. The left end 65a and the right end 65b of the torsion bar 65 protrude outward from the spring seats 9 and 10 in the vehicle width direction, respectively, and the rear end 64a of the arm 64 extending forward of the vehicle body is fixed to the protruding portion. The torsion bar 65 and the arm 64 constitute a substantially U-shaped stabilizer 15. The front ends 64b of the left and right arms 64 are rotatably connected to the lower ends of the left and right brackets 66, respectively.
Are fixedly fastened to the side walls 4 of the left and right side members 1 and 2, respectively. The left and right torque rods 14 extend forwardly of the vehicle body substantially parallel to the left and right arms 64,
b is rotatably connected to the left and right brackets 66, respectively. The stabilizer 15 and the torque rod 14 form a pair of parallel link mechanisms, and regulate the movement of the front axle 3 and exhibit an anti-roll effect.

Both ends of a cross member 70 arranged along the vehicle width direction are fixed to the left and right brackets 66. The cross member 70 has a wide upper surface 67, and a lower portion of the engine 72 is connected to the upper surface 67 via a mount rubber 71 as an elastic member. As a result, the engine 72 is supported by the cross member 70 from below via the mount rubber 71. The mount rubber 71 is formed of a material having a lower spring constant than the case where the engine 72 is supported from the side by the side members 1 and 2, and the upper surface 67 of the cross member 67 is designed to have a larger mounting area with respect to the engine 70. It is provided in a wide range.

According to this embodiment, the engine 72 is supported from below by the cross member 70 via the mount rubber 71. In such a state, the direction of the force acting on the mount rubber 71 by the crank rotation of the engine 70 is in the vehicle width direction. In addition, the direction of the force for deforming the mount rubber 71 by the mass of the engine 70 itself is the vertical direction.
That is, the direction in which a lower spring constant is desired to reduce vibration transmission (vehicle width direction) and the direction in which a higher spring constant is desired to improve durability (vertical direction) are:
The state is substantially orthogonal. Therefore, the force applied from the engine 70 to the mount rubber 71 is dispersed, and practically sufficient durability can be obtained even when the mount rubber 71 having a low spring constant is used.

Further, since the mounting area of the mounting rubber 71 is large, sufficient durability can be obtained even though the mounting rubber 71 having a low spring constant is used.

Therefore, it is possible to achieve both a reduction in vibration transmission from the engine 72 and an improvement in durability of the elastic member.

In the structure using the air spring 21, the stabilizer 15 required to obtain the anti-roll effect while restricting the movement of the front axle 3 is provided.
And a bracket 66 for supporting the torque rod 14
Is used to support the cross member 70, so that space can be saved by sharing parts, the number of parts can be reduced, and the structure can be simplified.

In this embodiment, the torque rod 14
And a structure having both the stabilizer 15 and the stabilizer 15, but the present invention can be applied to a structure having only a stabilizer which also has a function as a torque rod.

[0028]

As described above, according to the present invention,
It is possible to achieve both reduction in transmission of vibration from the engine and improvement in durability of the elastic member.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a vehicle body lower structure according to the present embodiment.

FIG. 2 is a plan view of the structure of FIG.

FIG. 3 is a side view of the structure of FIG. 1;

FIG. 4 is a cross-sectional view of a main part of the structure of FIG. 1 along a vehicle width direction.

[Explanation of symbols]

Reference Signs List 1 side member (first chassis frame) 2 side member (second chassis frame) 3 front axle (axle) 9 spring seat (first air spring support) 10 spring seat (second air spring support) 14 Torque rod 15 Stabilizer 17 First air spring 18 Second air spring 64 Arm 65 Torsion bar 70 Cross member 71 Mount rubber (elastic member) 72 Engine

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3D001 AA17 AA18 BA72 CA03 DA04 DA06 DA11 3D003 AA01 AA06 BB01 CA09 DA03 DA29

Claims (1)

[Claims] A first and a second chassis frame extending along the vehicle longitudinal direction on both sides in a vehicle width direction; an axle extending along a vehicle width direction below the first and second chassis frames; First and second air springs disposed between first and second chassis frames and the axle; and first and second air springs provided on both sides of the axle in the vehicle width direction to support the first and second air springs from below. A first and a second air spring supporting portion; a torsion bar having both ends arranged along a vehicle width direction and rotatably connected to the first and the second air spring supporting portion; A substantially U-shaped stabilizer having arms extending from both ends of the bar toward the front of the vehicle body; and a bracket for connecting a front end of each of the arms to the first and second chassis frames. Doo and are arranged along the vehicle width direction, with both ends connected to the bracket, underbody structure comprising: the cross member, the supporting the engine from below via the elastic member.