JP2002087038A - Rear suspension structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rear suspension structure that can provide a soft vibration transmission characteristic without an increase in vertical dimension, can permit control over a wheel toe angle at acceleration and deceleration, can improve the rigidity of a connection and can be structurally simple. SOLUTION: A bush 5 is arranged coaxially with a front connection of a radius arm 4 to a vehicle body structure member 6. The axis of the bush 5 is placed substantially vertically, so that vertical force is received in shearing force, which in turn ensures a soft vibration transmission characteristic, and that a small vertical dimension facilitates closeness of the center of oscillation of the radius arm 4 to the frame 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle such as an automobile, which has a front portion connected to a vehicle body structural member and a rear portion connected to a wheel housing which is supported on a vehicle body by supporting a wheel hub. The present invention relates to a rear suspension structure including arm members arranged in the front-rear direction.

[0002]

2. Description of the Related Art Conventionally, in a vehicle such as an automobile, a connecting portion between an arm of a suspension device and a vehicle body is generally supported by a bush having an axis substantially coinciding with a swing axis of the arm. . In particular, in the case of a trailing radius arm, it is desirable to lower the position of the wheel center with respect to the center of oscillation of the radius arm in order to prevent a dive during acceleration or a lift during deceleration. In order to improve the ride comfort of the vehicle and to pursue comfort such as suppression of transmission of vibrations, the bush diameter must be increased in the ordinary bush structure. When these bushes are attached to the lower part of the frame, the frame position relatively rises, and there is a possibility that the livability in the vehicle interior may be sacrificed, or the vehicle height may be increased to cause a decrease in steering stability. The optimal performance was determined from the balance of the characteristics.

Further, in the conventional bush, as shown in Japanese Patent Application Laid-Open No. 2000-25436 shown in FIG. 5, the swing center shaft 113 of the radius arm 110 is arranged substantially horizontally with respect to the vehicle body. For this reason, as shown in FIG. 6, which is an explanatory view of the rear suspension, when the bush 25 of the Asian arm 24 is supported below the frame member such as the rear frame 26, the bush inner cylinder 2
The bracket 28 for supporting the 4B horizontal shaft must be extended downward from the rear frame 26.

[0004]

Therefore, if an attempt is made to increase the diameter of the bush in order to obtain suitable vibration characteristics, the distance between the frame and the supporting portion of the bush is inevitably increased, and the mounting of the bracket 28 is inevitably increased. It is inevitable that the bracket 28 becomes large and complicated in view of securing the strength, for example, requiring additional means such as a reinforcing member 38 or the like.

Accordingly, the present invention solves the above-mentioned problems of the conventional rear suspension structure, can soften the vibration transmission characteristics without increasing the vertical bulk, and control the wheel toe angle during acceleration / deceleration. It is another object of the present invention to provide a rear suspension structure capable of improving the rigidity of the connecting portion and simplifying the structure.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a vehicle having a front part connected to a vehicle body structural member and a rear part connected to a wheel housing suspended from a vehicle body by supporting a wheel hub. In the rear suspension structure provided with the arm member, an elastic body is interposed between an outer cylinder and an inner cylinder disposed coaxially at a connection portion of the arm member with a vehicle body structural member at the front. And a shaft of the bush is arranged in a substantially vertical direction. Further, the invention is characterized in that the outer cylinder is fixed to the arm member, and the inner cylinder is connected at upper and lower ends to a vehicle body structural member. Further, the invention is characterized in that the arm member is formed integrally with a wheel housing. Further, the present invention is characterized in that the bush has a rigidity changing portion inclined with respect to the traveling direction of the vehicle body.
Further, according to the present invention, the vehicle body structural member includes a hollow frame member extending at least in a vehicle front-rear direction, and a separator installed with a surface substantially parallel to upper and lower surfaces of the frame member and one of the upper and lower surfaces. While installing a tube between, the arm member extends from the vehicle body structural member, the inner tube of the arm member is sandwiched between the tube and the tip of the arm member, the tube, the inner tube and It is characterized by being connected by a bolt inserted into the arm member, because the vertical force acting on the bush of the arm member is received by the shearing force of the bush, without increasing the vertical bulk, relatively The vibration transmission characteristics can be softened, and the living performance and the vehicle height are not adversely affected.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a rear suspension structure according to the present invention will be described below with reference to the drawings. 1 to 3 show an embodiment of a rear suspension structure of the present invention. FIG. 1 is a side view of a main part and an enlarged perspective view of the vicinity of a bush, FIG. 2 is a plan view of a radius arm, and FIG. )
FIG. As shown in FIG. 1, a wheel housing 3 has a front portion connected to a vehicle body structural member 6 and a rear portion supported on a vehicle body by pivotally supporting a hub 2 (FIG. 3) of a wheel 1.
In the rear suspension structure including the radius arm 4 connected to the body, an elastic body 5A is provided between an outer cylinder 4A and an inner cylinder 4B coaxially arranged at a connection portion of the front portion of the radius arm 4 with the vehicle body structural member 6. It is characterized in that a bush 5 configured to be interposed is arranged, and the axis of the bush 5 is arranged in a substantially vertical direction.

More specifically, as shown in FIG. 1C, the outer cylinder 4A constituting the bush 5 is fixed to the front part of the radius arm 4 (or may be integrally formed), and
A hole 5B for setting the rigidity, that is, the elasticity of the bush, is formed in an elastic body 5A such as rubber interposed between B and B. The inner cylinder 4B of the bush 5 is connected at its upper and lower ends to a vehicle body structural member, that is, a rear frame 6, and a stopper bracket 13 which is an arm member described later. Also,
The radius arm 4 is integrally formed with the wheel housing 3 (may be formed integrally, or may be formed separately and combined with each other).

The vehicle body structural member includes a hollow frame member such as a rear frame 6 extending at least in the vehicle longitudinal direction, and a separator 8 provided with a surface substantially parallel to upper and lower surfaces of the frame member. The tube 9 is installed between one of the upper and lower surfaces of the frame member (the lower surface in the illustrated example), and the arm member is a stopper for the arm member from the body structural member (the floor side member 12 shown in FIG. 3). The bracket 13 is extended, and the inner cylinder 4B of the radius arm 4 is provided between the pipe 9 and the tip of the stopper bracket 13.
And connected by a bolt 18 inserted through the tube 9, the inner tube 4B and the arm member 13. FIG.
The arrangement of the stopper bracket 13 is clearly understood from the bottom view of FIG. In FIG. 3, reference numeral 7 denotes a side sill,
10 is a cross member, 11 is a floor pan front, 14
Is a tunnel for a propeller shaft, 15 is a tire, 1
Reference numerals 6 and 17 denote a lower arm and an upper arm of the suspension.

With such a configuration, since the axis of the bush 5 of the connecting portion of the radius arm 4 to the vehicle body structural member 6 is oriented in the up-down direction, the bush 5 can be connected between the inner and outer cylinders without increasing the bulk in the up-down direction. And the vibration transmission characteristic can be softened in combination with receiving the vertical force acting on the bush 5 by the shearing force. And, due to the small bulk of the bush 5 in the vertical direction,
It is easy to bring the center of swing of the radius arm 4 close to the rear frame 6, so that the occupant's cabin is not narrowed and the comfort is not impaired, and the vehicle height is increased and the steering stability is not impaired. In addition, the separator 8 extends through the frame.
The bushing 5 of the radius arm 4 is firmly fixed and connected after the bush 5 of the radius arm 4 is secured to a certain extent by the bolts 18 and the like by the tube 9 firmly arranged in the vertical direction by the supporting member also serving as reinforcement. Therefore, even if the size of the bush 5 is changed, it is not necessary to largely change the mounting members such as the separator 8 and the arm member, such as the stopper bracket 13, so that the rigidity of the connecting portion can be improved and the structure can be simplified.

As shown in FIG. 2, the bush 5 has a rigidity changing portion inclined with respect to the traveling direction of the vehicle body. That is, the elastic member 5A such as rubber interposed between the inner and outer cylinders 4A and 4B of the bush 5 is configured such that the hole 5B is located at a position inclined with respect to the traveling direction of the vehicle body, so that the wheel 1 is formed. The toe-in behavior of the radius arm 4 due to the braking force generated between the tire 15 and the road surface when braking (dotted line in FIG. 2) or the toe-out behavior during acceleration is designed to control the toe angle appropriately. It becomes possible to do.

As shown in FIG. 4A, generally,
The rear frame 6 to which the radius arm 4 is connected causes low-frequency vibration of about 5 to 15 Hz due to its own natural vibration to repeatedly deform as indicated by a dotted line, thereby causing a displacement at the front connection portion of the radius arm 4. But
In the case of the present invention, it is possible to make the vibration characteristics of the rear frame 6 function in the suppression direction by the presence of the stopper bracket 13 which is an arm member for sandwiching and supporting the inner cylinder 4B at the front portion of the radius arm 4. became. FIG. 4 (B) is an experimental result diagram showing the relationship between the frequency corresponding to the natural vibration and the vibration acceleration. It is understood that the vibration acceleration decreases.

The embodiments of the present invention have been described above. However, within the scope of the present invention, the shape and type of the wheel housing and the radius arm and the related configuration between them, the material of the elastic body and its hole, The shape and type of the bush, including the arrangement form, its configuration with the radius arm, the shape of the tube, the form of installation on the frame member via the separator, etc. of the tube, the shape of the arm member and its shape to the body structural member The installation form, the connection form of the bush to the tube and the arm member, and the like can be appropriately selected.

[0014]

As described above in detail, according to the present invention, the front portion is connected to the vehicle body structural member, and the rear portion is connected to the wheel housing which is supported by the vehicle body while supporting the wheel hub. In a rear suspension structure including an arm member extending in the front-rear direction, an elastic body is interposed between an outer cylinder and an inner cylinder disposed coaxially at a connection portion of a front part of the arm member with a vehicle body structural member. By arranging the bush, the bush is arranged in a substantially vertical direction, the thickness between the inner and outer cylinders of the bush is increased without increasing the bulk in the vertical direction. The vibration transmission characteristics can be softened in combination with the shear force, and the small vertical bulk of the bush makes it easy to bring the swing center of the arm member closer to the frame. The or impair the comfort of narrow,
The height of the vehicle does not increase and steering stability is not impaired.

When the outer cylinder is fixed to the arm member, and the inner cylinder is connected to the body structural member at the upper and lower ends thereof, the outer cylinder rigidly fixed to the arm member can be easily connected to the body structure. A bush with an elastic body interposed therebetween can be easily mounted between the inner cylinder sandwiched and connected by the members with the shaft thereof oriented substantially vertically. Further, when the arm member is integrally formed with the wheel housing, the arm member that constantly swings as a suspension and the wheel housing can be configured as a large strength member as an integrated arm member. Furthermore, when the bush has a stiffness changing portion that is inclined with respect to the traveling direction of the vehicle body, an appropriate toe angle control is performed for the toe-in behavior of the arm member by the braking force or the toe-out behavior during acceleration. It becomes possible to design.

The vehicle body structural member includes a hollow frame member extending at least in the vehicle front-rear direction, and a separator provided with a surface substantially parallel to upper and lower surfaces of the frame member and one of the upper and lower surfaces. An arm member extends from the vehicle body structural member, and an inner tube of the radius arm is sandwiched between the tube member and a tip portion of the arm member. When connected by bolts inserted through the members, the bushing of the arm member is limited to a certain extent by bolts etc. Since the span can be secured, it can be fixed and connected firmly. There is no need to greatly change the members, simplification of improvement and structural rigidity of the connecting portion can be realized. As described above, according to the present invention, the vibration transmission characteristics can be softened without increasing the vertical bulk, the toe angle of the wheel can be controlled at the time of acceleration / deceleration, and the rigidity of the connecting portion can be improved and the structure can be improved. A rear suspension structure that can be simplified is provided.

[Brief description of the drawings]

FIG. 1 shows a rear suspension structure according to an embodiment of the present invention, and is a side view of a main part and an enlarged perspective view of the vicinity of a bush.

FIG. 2 is a plan view of the radius arm.

FIG. 3 is a bottom view of FIG.

FIG. 4A is a diagram showing a state of natural vibration of the rear frame, and FIG. 4B is an experimental result diagram showing a relationship between a frequency corresponding to the natural vibration and a vibration acceleration.

FIG. 5 is a perspective view of a main part showing a conventional rear suspension structure.

FIG. 6 is an explanatory diagram of the same rear suspension.

[Explanation of symbols]

 Reference Signs List 3 wheel housing 4 radius arm (arm member) 4A support outer tube 4B support inner tube 5 bush 5A elastic body 5B hole 6 rear frame (frame member: body structural member) 8 separator 9 tube 12 floor side member (body structural member) 13 Detent bracket (arm member: body structural member) 18 Bolt

Claims (5)

[Claims] 1. A rear suspension structure comprising: a front portion connected to a vehicle body structural member; and a rear portion connected to a wheel housing suspended from the vehicle body by supporting a wheel hub. A bush having an elastic body interposed between an outer cylinder and an inner cylinder disposed coaxially at a connecting portion of the arm member with a vehicle body structural member at a front portion thereof; The rear suspension structure is characterized in that the shafts are arranged substantially vertically. 2. The rear suspension structure according to claim 1, wherein said outer cylinder is fixed to said arm member, and said inner cylinder is connected to a vehicle body structural member at upper and lower ends thereof. 3. The rear suspension structure according to claim 1, wherein the arm member is formed integrally with a wheel housing. 4. The bush according to claim 1, wherein the bush has a rigidity changing portion inclined with respect to a traveling direction of the vehicle body.
4. The rear suspension structure according to any one of claims 3 to 3. 5. The vehicle body structural member includes a hollow frame member extending at least in a vehicle front-rear direction, and a separator provided with a surface substantially parallel to upper and lower surfaces of the frame member and one of the upper and lower surfaces. While installing a tube between, the arm member extends from the vehicle body structural member, the inner tube of the arm member is sandwiched between the tube and the tip of the arm member, the tube, the inner tube and The rear suspension structure according to any one of claims 1 to 4, wherein the rear suspension structure is connected by a bolt inserted through the arm member.