JP2005119363A - Torsion beam type suspension - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a torsion beam type suspension capable of preventing a torsion beam from being twisted and setting the hardness of bushing joints made of rubber so as to assure good ride comfort. <P>SOLUTION: The torsion beam type suspension 100 is structured so that the middle part of a trailing arm 4 with its front end pivoted on a vehicle body through each bushing joint 3 and rear end suspending each vehicle wheel W is connected with the two ends of the torsion beam 5 extending to the left and right of the vehicle body. Brackets 2 and 3b to hold a torsion bar 1 in such a way as capable of being twisted and a coupling arm 13 are installed between the left and right bushing joints 3, and torques for rotating the left and right brackets 2 round the bushing joints 3 in the opposite directions to each other are generated when the bushing joints 3 make relative movement in the direction fore and aft of the vehicle body, and thereby the torsion bar 1 generates a restoring force. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an automobile suspension, and more particularly to a torsion beam type suspension having a torsion bar between left and right bush joints arranged on the left and right sides of the suspension.

  The suspension of an automobile, while running, bounces and rebounds from the left and right wheels, and a torsional stress is applied to the suspension. .

FIG. 5 is a perspective view of the torsion beam suspension of the rear wheel as viewed obliquely from the left front of the vehicle body. FIG. 6 is a perspective view of the left half of the torsion beam suspension 200 shown in FIG. 5 as viewed obliquely from the rear of the vehicle body.
As shown in FIGS. 5 and 6, the torsion beam suspension 200 for suspending the rear wheels W of the automobile is composed of a pipe member that is loosely bent and extends in the front-rear direction of the vehicle body. 24. As shown in FIG. 6, the trailing arm 24 has a rubber bush joint 23 provided at the front end thereof supported by a bracket 28 on the vehicle body so as to swing up and down, and a rear end of the trailing arm 24 via a bracket 32. A rear wheel W is rotatably supported on an axle 29 fixed in the left-right direction. Further, the lower end of the shock absorber 33 that attenuates the vertical swing of the trailing arm 24 is connected to a bracket 34 that is fixed to an intermediate portion in the front-rear direction of the trailing arm 24. The lower end of the suspension spring 26 that cushions the vertical impact applied to the trailing arm 24 is supported by a spring seat 31 fixed to the rear end of the trailing arm 24.

  And as shown in FIG. 5, it is in the front-rear direction intermediate part of the left and right trailing arms 24, 24, that is, the position sandwiched between the rubber bush joints 23, 23 and the bracket 34 (see FIG. 6) of the shock absorbers 33, 33. The left and right ends of the torsion beam 25 extending in the left-right direction of the vehicle body are coupled via gussets 35, 35, respectively. The gusset 35 is welded to the torsion beam 25 and the trailing arm 24, and reinforces the torsion beam 25.

  FIG. 7 shows a state in which torsional stress acts on the torsion beam 25, and is a schematic view of the torsion beam suspension 200 viewed from above the vehicle. As shown in FIG. 7, the upper side in the figure is the front of the vehicle body. When the left and right rear wheels W, W move up and down as the automobile travels, the left and right trailing arms 24, 24 swing up and down around the rubber bush joints 23, 23. The vibration generated at this time is buffered and damped by the suspension spring 26 and the shock absorber 33. Further, the left and right rear wheels W, W cause a shift in the phase of the rear wheels W, W when bound and rebound. At this time, the left and right trailing arms 24, 24 swing around the rubber bush joint 23, and the swinging angle becomes uneven and the torsion beam 25 is twisted. Along with this, the elastic restoring force provided in the torsion beam 25 acts so as to equalize the angle at which the left and right trailing arms 24, 24 swing.

  As shown in FIG. 7, the positions of the rear wheels W, W are located on the outer side in the left-right direction with respect to the positions of the rubber bush joints 23, 23. When a rearward load is applied due to a collision, a moment M is generated that moves the rear part of the trailing arms 24, 24 in the left-right direction, and acts to change the toe angle α of the rear wheels W, W. . In addition, even when a lateral force F is applied to the rear wheels W, W due to turning of the vehicle body, a moment M that causes the rear portions of the trailing arms 24, 24 to move in the left-right direction is generated, causing the rear wheels W, W to toe. Try to change the angle α.

  However, since the connecting portions between the left and right trailing arms 24 and 24 and the torsion beam 25 are reinforced by the gussets 35 and 35, respectively, and the relative angular displacement is restricted, the trailing arms 24 and 24 swing left and right. The toe rigidity of the rear wheels W and W is increased.

  Further, since the welded portion of the gussets 35 and 35 that couple the torsion beam 25 and the trailing arm 24 is located in the vicinity of the coupling portion between the torsion beam 25 and the trailing arm 24 that is the center of torsion beam 25 twist, In addition to minimizing the influence of the torsion beam 25 on the torsion beam 25, the function of the torsion beam 25 can be fully exerted, and the displacement caused by the torsion applied to the welded portion can be suppressed as much as possible to improve durability. it can.

Further, by providing a concave fragile portion that relieves stress concentration at the connecting portion between the torsion beam 25 and the trailing arm 24 at a portion other than the connecting portion, the strength of the connecting portion is prevented from lowering and the durability of the suspension is improved. A torsion beam suspension is disclosed (for example, see Patent Document 1).
Japanese Patent Laid-Open No. 10-236123 (paragraphs 0023 and 0025, FIG. 3)

However, the left and right wheels bounce and rebound, respectively, and the torsion beam 25 is further twisted, resulting in a problem that the torsional rigidity of the torsion beam 25 is greatly affected.
Further, when the lateral stiffness at the ground contact point of the tire W is structurally low and the side force (lateral force) at the time of turning is large, the tire W tends to toe out (TUE OUT). That is, the tire W is slightly outward with respect to the traveling direction of the automobile. For this reason, the hardness of the rubber bush joint has to be increased, and it has been difficult to achieve both a comfortable ride.

  The present invention has been made to solve the above-mentioned problems, and provides a torsion beam suspension capable of preventing torsion of the torsion beam and setting the hardness of a rubber bush joint formed of a rubber material with a comfortable ride. The task is to do.

  The invention according to claim 1 of the present invention that solves the above-mentioned problems extends in the front-rear direction of the vehicle body in a pair of left and right sides, its front end is pivotally supported by the vehicle body via a bush joint, and its rear end is a wheel. A torsion beam suspension in which an intermediate portion of a suspended trailing arm is connected to both ends of a torsion beam extending in the left-right direction of the vehicle body, and a torsion bar is provided between one and the other of the left and right bush joints. It is characterized by.

According to the first aspect of the present invention, since the torsion bar is provided between one of the left and right bush joints, the other moves relative to one of the left and right bush joints in the longitudinal direction of the vehicle body. In this case, the torsion bar can generate a restoring force that resists torsional stress acting on the torsion bar, thereby preventing the torsion beam from being twisted. Thus, the hardness of the rubber bush joint can be set with good riding comfort without applying a large load to the rubber bush joint formed of the rubber material.
Here, the rubber bush joint corresponds to a “bush joint” in the claims.

  According to a second aspect of the present invention, in the first aspect of the present invention, the left and right bush joints include a bracket for holding the torsion bar in a twistable manner.

  According to the second aspect of the invention, in addition to the action of the first aspect of the invention, when the other of the left and right bush joints moves relative to the longitudinal direction of the vehicle body, the left and right bushes The joint generates a rotational force that rotates the left and right brackets around the left and right bush joints in the opposite directions, causing the torsion bar to twist. The torsion bar can be transmitted to the torsion bar, and the torsion beam can be prevented from being twisted. For this reason, it is possible to set the hardness of the rubber bush joint in a comfortable manner without giving a large load to the rubber bush joint formed of the rubber material.

  According to the present invention, a force for generating a twist in the torsion beam can be transmitted to the torsion bar by the bracket, and the torsion beam can be prevented from being twisted by the elastic restoring force of the torsion bar. This makes it possible to set the hardness of the rubber bush joint in a comfortable manner without giving a large load to the rubber bush joint formed of the rubber material.

A torsion beam suspension according to an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 (a) is a perspective view of a rear wheel torsion beam suspension as viewed from the diagonally left front of the vehicle body. FIG.1 (b) is detail drawing of the A section shown to Fig.1 (a). FIG. 2 is a perspective view of the left half of the torsion beam suspension 100 shown in FIG. FIG. 3 is a plan view of FIG.
As shown in FIGS. 1, 2, and 3, a torsion beam suspension 100 for suspending a rear wheel W of an automobile is constituted by a pair of left and right trailing arms that are formed of a pipe member that is loosely bent and extends in the front-rear direction of the vehicle body. 4,4 are provided. As shown in FIG. 2, the trailing arm 4 has a rubber bush joint 3 provided at a front end thereof supported by a bracket 8 on the vehicle body so as to be swingable up and down, and a rear end of the trailing arm 4 via a bracket 12. A rear wheel W is rotatably supported on an axle 9 fixed in the left-right direction. As shown in FIG.1 (b), the rubber bush joint 3 is formed with the metal material in which the rubber | gum 3a was incorporated. A bracket 3 b is welded to the rubber bush joint 3, and the bracket 3 b is rotatably connected to a ball joint 13 b that is one end of a connecting arm 13. A ball joint 13 a is provided at the other end of the connecting arm 13 and is connected to the lower end of the bracket 2 so as to be freely rotatable. A torsion bar 1 is fixed to the bracket 2 via a fixing member 2a. The torsion bar 1 is provided with brackets 10 on the left and right. The bracket 10 is engaged with the torsion bar 1 via a rubber material 10a. The bracket 10 functions as a bracket for holding the torsion bar 1 on the floor (not shown) of the vehicle body in a twistable manner. As shown in FIG. 2, the lower end of the shock absorber 7 that attenuates the vertical swing of the trailing arm 4 is connected to a bracket 14 fixed to the rear end of the trailing arm 4. Further, the lower end of the suspension spring 6 that cushions the impact in the vertical direction applied to the trailing arm 4 is supported by a spring seat 11 fixed to the intermediate portion in the front-rear direction of the trailing arm 4.
The brackets 2 and 3b referred to here correspond to “brackets” in the claims.

  And as shown in FIG. 3, the left-right both ends of the torsion beam 5 extended in the left-right direction of a vehicle body in the front-back direction intermediate part of the trailing arm 4, ie, the position pinched by the bracket 11 of the rubber bush joint 3 and the suspension spring 6 The parts are connected to each other via a gusset 15.

Next, the operation of the torsion beam suspension having the above configuration will be described. FIG. 4 shows a state in which a torsional stress acts on the torsion beam 5, and FIG. 4 (a) is a perspective view of the rear wheel torsion beam suspension as viewed from the diagonally left front of the vehicle body. FIG. 4B is a schematic view of the left rear wheel portion of FIG. 4A viewed from above the vehicle.
As shown in FIG. 4 (a), when the left and right rear wheels W, W move up and down as the vehicle travels, the left and right trailing arms 4, 4 move up and down around the rubber bush joints 3, 3. Swing. The vibration generated at this time is buffered and damped by the suspension spring 6 and the shock absorber 7. Further, when the left and right rear wheels W, W bounce and rebound, the phases of the rear wheels W, W are shifted. At this time, the left and right trailing arms 4, 4 swing around the rubber bush joint 3, and the swinging angle becomes uneven and the torsion beam 5 is twisted. Along with this, the elastic restoring force provided to the torsion beam 5 acts to make the angle at which the left and right trailing arms 4 and 4 swing are uniform. At this time, the torsional stress of the torsion beam 5 due to the phase shift is transmitted as a rotational force to the bracket 2 and acts to cause the torsion bar 1 to be twisted.

  For example, as shown in FIG. 4B, the left rear wheel W is located on the left outer side with respect to the position of the rubber bush joint 3. For this reason, when the left rear wheel W collides with a protrusion on the road surface, the left rear wheel W is loaded toward the rear of the vehicle body. At this time, a moment M that moves the rear part of the trailing arm 4 in the right direction is generated, and the left rear wheel W tries to change its toe angle α. Even when a lateral force F is applied to the left rear wheel W by turning the vehicle body or the like, a moment M that moves the rear part of the trailing arm 4 to the right is generated, and the left rear wheel W Try to change the angle α.

  Since the connecting portion between the trailing arm 4 and the torsion beam 5 is reinforced by the gusset 15 and the relative angular displacement is restricted, the trailing arm 4 is less likely to swing left and right. Toe rigidity is increased.

  Further, since the welded portion of the gusset 15 that couples the torsion beam 5 and the trailing arm 4 is located in the vicinity of the coupling portion between the torsion beam 5 and the trailing arm 4 that is the center of twist of the torsion beam 5, Not only can the effect of the torsion beam 5 be minimized, but the function of the torsion beam 5 can be fully exerted, and the torsion beam suspension 100 can be improved in durability by minimizing the torsion applied to the welded portion. .

  However, further improvement in toe rigidity is required, and therefore, the torsion bar 1 is provided in the present embodiment. As shown in FIG. 4 (a), the torsion bar 1 is provided between one and the other of the left and right bush joints 3 and 3, so that the other of the left and right rubber bush joints 3 and 3 is the front and rear of the vehicle body. When the torsion bar 1 moves relative to the direction, the torsion bar 1 can generate a restoring force that resists torsional stress acting on the torsion bar 1, thereby preventing torsion of the torsion beam 5. That is, the torsion bar 1 generates a restoring force, and the rotational force applied to the bracket 2 and the bracket 3b (see FIG. 1B) can be attenuated. Thereby, the hardness of the rubber bush joint 3 can be set with good riding comfort without giving a large load to the rubber bush joint 3 formed of a rubber material.

Further, the lateral rigidity F at the ground contact point can be increased against the lateral force F acting when the vehicle body is turned by the restoring force of the torsion bar 1, and the toe-out amount can be suppressed.
Further, when a force in the front-rear direction of the vehicle body acts simultaneously with the lateral force F due to bounce or rebound, the restoring force of the torsion bar 1 does not act because the forces interfere with each other.
Further, when the vehicle body bounces or rebounds due to the force in the front-rear direction without the lateral force F acting, the trailing arms 4 and 4 swing in the same phase on the left and right sides of the vehicle body. In such a case, the rotational force does not act on the bracket 2 coupled to the torsion bar 1 and the bracket 3b coupled to the bracket 2, and the restoring force of the torsion bar 1 does not act. At this time, the spring constant remains low. For this reason, the hardness of the rubber bush joint 3 can be set with good riding comfort. Thereby, the rubber bush joint 3 functions as a flexible compliance bush, and it is possible to always achieve both steering stability and riding comfort without sacrificing riding comfort.

  The preferred embodiments have been described above. However, the present invention is not limited to the above-described embodiments, and appropriate modifications can be made without departing from the scope of the present invention. For example, in the present embodiment, the bracket that supports the torsion bar is joined to the metal cylinder holding the rubber bush joint by welding, but is not limited to welding, and may be fixed by a bolt.

(A) is the perspective view which looked at the torsion beam type suspension which concerns on one embodiment of this invention from the diagonally left front of the vehicle body. (B) is a detail drawing of the A section shown in (a). FIG. 2 is a perspective view of the left half of the torsion beam suspension shown in FIG. FIG. 3 is a plan view of FIG. 2. FIG. 3A shows a state in which a torsional stress acts on a torsion beam. FIG. 3A is a perspective view of a torsion beam type suspension of a rear wheel as viewed obliquely from the left front side of the vehicle body, and FIG. It is the schematic diagram seen from the vehicle upper direction. It is the perspective view which looked at the conventional torsion beam type suspension from the diagonally left front of the vehicle body. FIG. 6 is a perspective view of the left half of the torsion beam suspension shown in FIG. It is the schematic diagram which showed a mode that the torsional stress acted on the conventional torsion beam.

Explanation of symbols

1 Torsion bar 2 Bracket 3 Rubber bush joint (compliance bush joint)
3b Bracket 4 Trailing arm 5 Torsion beam 6 Suspension spring 7 Shock absorber 8 Bracket 9 Axle 10 Bracket 11 Spring seat 12 Bracket 13 Connecting arm 13a Ball joint 13b Ball joint 14 Bracket 15 Gusset 100 Torsion beam suspension W Wheel

Claims (2)

A middle part of a trailing arm that extends in the longitudinal direction of the vehicle body in a pair of left and right, whose front end is pivotally supported by the vehicle body via a bush joint, and whose rear end suspends a wheel,
A torsion beam suspension connected to both ends of a torsion beam extending in the left-right direction of the vehicle body,
A torsion beam suspension, wherein a torsion bar is provided between one of the left and right bush joints.   The torsion beam suspension according to claim 1, wherein the left and right bush joints include a bracket for holding the torsion bar in a twistable manner.

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