Suspension device for vehicles

A suspension device (rear suspension (10)) for vehicles is provided which includes a damper (40), a shaft (50) pivotably supporting an end of the damper (40), and a bush (60) including a cylindrical elastic member fitted onto the outer circumference of the shaft (50). The axis (C2) of the bush (60) is disposed along a line of intersection between an imaginary first plane (S1) and an imaginary second plane (S2), or along a line parallel to the line of intersection. The first plane (S1) is orthogonal to the axis (C1) of the damper (40) when a stroke position of a wheel (24) is a first position relative to the vehicle body (80) in the vertical direction of a vehicle body (80). The second plane (S2) is orthogonal to the axis (C1) of the damper (40) when the stroke position of the wheel (24) is a second position.

TECHNICAL FIELD

The present invention relates to a suspension device for vehicles.

BACKGROUND ART

An extendable and retractable damper of a suspension device for vehicles is described in, for example, Patent Document 1. This damper is mounted such that the lower end of the damper is connected to a wheel of the vehicle via components such as a knuckle, and the upper end of the damper is connected to a vehicle body of the vehicle. When the wheel rides up and down (i.e., bumps and rebounds) relative to the vehicle body, the damper is retracted or extended while changing its orientation (an inclination angle relative to the vertical direction of the vehicle body) as appropriate in accordance with the change in positional relation of the damper between the upper end (vehicle body) and the lower end (wheel).

The lower end and/or the upper end of such dampers are, in some cases, pivotably supported by a certain shaft via a bush including an elastic member that is fitted onto the outer circumference of the shaft.

When the wheel rides up and down on bumps and rebounds, the damper pivots about the axis of the bush and causes torsion (rotation about the axis of the bush) in the bush. At the same time, the angle between the axis of the bush and the axis of the damper varies, which causes deformation of the bush due to prying forces (rotation about an axis perpendicular to the axis of the bush). Such torsion and deformation due to prying forces cause reaction force from the bush, and the reaction force increases friction in the damper and prevents smooth operation of the damper. Lack of smoothness of the damper may degrade ride comfort or handling stability of the vehicle.

In general, the spring constant of a bush about an axis perpendicular to the axis of the bush is about twice as great as the spring constant about the axis of the bush. In this regard, a larger reaction force is generated from the deformation due to prying forces than from the torsion of the bush when the wheel rides up and down on bumps and rebounds. To operate the damper smoothly, reducing such deformation of the bush due to prying forces is more effective.

Such deformation due to prying forces can occur in the bush when the axis of the bush is arranged to be inclined relative to the direction perpendicular to the axis of the damper. If the axis of the bush is disposed along the direction perpendicular to the axis of the damper and this disposition is kept regardless of the stroke position of the wheel relative to the vehicle body in the vertical direction of the vehicle body, the deformation of the bush due to prying forces can be prevented on all occasions.

CITATION LIST

Patent Document

SUMMARY OF THE INVENTION

Technical Problem

However, designing a vehicle suspension device has various restrictions on layout in relation to the nearby components, and accordingly, dampers are often arranged to be inclined relative to the vertical direction of the vehicle body. The inclination angle varies in accordance with the bump and rebound strokes of the wheel.

Even if the axis of the bush is disposed along the direction perpendicular to the axis of the damper in a certain stroke state of the wheel, the axis of the bush is inclined relative to the direction perpendicular to the axis of the damper in another stroke state of the wheel. It is therefore difficult to prevent deformation of the bush due to prying forces on all occasions.

The present invention has been made in view of the foregoing, and it is an object of the present invention to provide a suspension device for vehicles that can prevent deformation, due to prying forces, of a bush for use to support an end of a damper, regardless of a stroke position of a wheel relative to the vehicle body in the vertical direction of the vehicle body.

Solution to the Problem

To achieve the object above, an embodiment of the present invention is directed to a suspension device for vehicles including: a damper disposed between a wheel of a vehicle and a vehicle body of the vehicle and configured to extend and retract between the wheel and the vehicle body; a shaft configured to pivotably support an end of the damper; and a bush including a cylindrical elastic member fitted onto an outer circumference of the shaft and interposed between the shaft and the damper. An axis of the bush is disposed along a line of intersection between an imaginary first plane and an imaginary second plane, or along a line parallel to the line of intersection, the first plane being orthogonal to an axis of the damper when a stroke position of the wheel is a first position relative to the vehicle body in a vertical direction of the vehicle body, the second plane being orthogonal to the axis of the damper when the stroke position of the wheel is a second position different from the first position.

This configuration can substantially prevent deformation of the bush due to prying forces by disposing the axis of the damper so as to be orthogonal to the axis of the bush when the stroke position of the wheel is either the first position or the second position relative to the vehicle body in the vertical direction of the vehicle body. When the stroke position of the wheel is at any position between the first position and the second position, this configuration allows the intersection angle between the axis of the damper and the axis of the bush to be always close to the right angle, and thus can effectively reduce deformation of the bush due to prying forces.

Setting the first position and the second position properly as the stroke position of the wheel can effectively reduce deformation of the bush due to prying forces in various stroke states of the wheel during a drive, which can in turn effectively reduce an increase in friction in the damper caused by the reaction force of the bush. In this regard, the damper can operate smoothly, thereby providing a better ride comfort and handling stability of the vehicle.

According to an aspect of the suspension device for vehicles, the first position is close to a bump side relative to a predetermined reference position and the second position is close to a rebound side relative to the reference position.

The predetermined reference position can be determined freely. The predetermined reference position may be a position when, for example, the vehicle stopping on a horizontal road surface carries a certain amount of load. The certain amount of load can be determined freely. The certain amount of load may be, for example, a load of the vehicle carrying no person or no cargo, but with a full fuel tank.

The bump side indicates the upward stroke of the wheel toward the vehicle body and the rebound side indicates the downward stroke of the wheel away from the vehicle body.

The above configuration can dispose the axis of the damper so as to be orthogonal to the axis of the bush when the stroke position of the wheel is the first position close to the bump side relative to the predetermined reference position and when the stroke position of the wheel is the second position close to the rebound side relative to the predetermined reference position. This configuration can substantially prevent deformation of the bush due to prying forces. In addition, the above configuration can effectively reduce deformation of the bush due to prying forces when a wheel burns and rebounds while the vehicle is running. In this regard, the damper operates smoothly, thereby providing good ride comfort and good handling stability of the vehicle.

The second position according to the above aspect may be a position in which the damper is most extended.

This configuration can dispose the axis of the damper so as to be orthogonal to the axis of the bush when the stroke position of the wheel is the second position in which the damper is most extended. When the stroke position of the wheel is at any position between the predetermined reference position and the second position (that is, at any stroke position in the entire range of the wheel stroke from the predetermined reference position to the position closest to the rebound side), the intersection angle between the axis of the damper and the axis of the bush is always an angle close to the right angle. This configuration can effectively reduce deformation of the bush due to prying forces when the wheel rebounds.

This configuration also makes it possible to mount the bush to a predetermined position without any deformation of the bush due to prying forces when the bush is mounted to a certain position with the damper fully extended in a vehicle production process. The second position may be determined in this mounting process.

The first position according to the above aspect may be a position at a time when two people having a certain weight are seated in the front seats of the vehicle stopping on a horizontal road surface.

This configuration can substantially reduce deformation of the bush due to prying forces when a driver and a passenger are seated in the front seats (the driver's seat and the passenger seat) of the vehicle, which is a situation typically and highly frequently seen in a vehicle. This configuration can provide a better ride comfort and handling stability of the vehicle.

The first position according to the above aspect may be a position in which the damper is most retracted.

This configuration can dispose the axis of the damper so as to be orthogonal to the axis of the bush when the stroke position of the wheel is the first position in which the damper is most retracted. When the stroke position of the wheel is at any position between the predetermined reference position and the first position (that is, at any stroke position in the entire range of the wheel stroke from the predetermined reference position to the position closest to the bump side), the intersection angle between the axis of the damper and the axis of the bush is always an angle close to the right angle. This configuration can effectively reduce deformation of the bush due to prying forces when the wheel bumps.

According to another aspect of the suspension device for vehicles, the suspension device further includes: a knuckle configured to support the wheel; a trailing arm connected to the knuckle and extending in a vehicle's longitudinal direction; and a connecting part configured to connect a front portion of the trailing arm in the vehicle's longitudinal direction to the vehicle body. The axis of the damper is inclined inward in a vehicle width direction toward a top of the vehicle. The bush is fitted onto the outer circumference of the shaft that connects a lower end of the damper to a rear portion of the trailing arm in the vehicle's longitudinal direction. The axis of the bush is inclined frontward in the vehicle's longitudinal direction toward an inside in the vehicle width direction.

As described above, the axis of the damper is inclined inward in the vehicle width direction toward the top of the vehicle, and the lower end of the damper is connected to the rear portion of the trailing arm via the shaft and the bush. In this configuration, disposing the axis of the bush so as to be inclined frontward in the vehicle's longitudinal direction toward the inside in the vehicle width direction allows the axis of the damper to be disposed at the right angle with respect to the axis of the bush when the stroke position of the wheel is the first position and when the stroke position is the second position. This is a specific example to implement the present invention.

According to still another aspect of the suspension device for vehicles, the suspension device further includes: a knuckle configured to support the wheel; a trailing arm connected to the knuckle and extending in a vehicle's longitudinal direction; and a connecting part configured to connect a front portion of the trailing arm in the vehicle's longitudinal direction to the vehicle body. The axis of the damper is inclined outward in a vehicle width direction toward a top of the vehicle. The bush is fitted onto the outer circumference of the shaft that connects a lower end of the damper to a rear portion of the trailing arm in the vehicle's longitudinal direction. The axis of the bush is inclined rearward in the vehicle's longitudinal direction toward an inside in the vehicle width direction.

As described above, the axis of the damper is inclined outward in the vehicle width direction toward the top of the vehicle, and the lower end of the damper is connected to the rear portion of the trailing arm via the shaft and the bush. In this configuration, disposing the axis of the bush so as to be inclined rearward in the vehicle's longitudinal direction toward the inside in the vehicle width direction allows the axis of the damper to be disposed at the right angle with respect to the axis of the bush when the stroke position of the wheel is the first position and when the stroke position is the second position. This is another specific example to implement the present invention.

Advantages of the Invention

As described above, a suspension device for vehicles according to the present invention can effectively reduce deformation of a bush due to prying forces in various stroke states of the wheel during a drive. This configuration can effectively reduce an increase in friction in the damper caused by the reaction force of the bush. In this regard, the damper can operate smoothly, thereby providing a better ride comfort and handling stability of the vehicle.

DESCRIPTION OF EMBODIMENT

FIG. 1illustrates a rear suspension10(hereinafter simply referred to as a suspension10) that is a suspension device for vehicles according to an exemplary embodiment. In the following description, the front and rear, left and right, and top and bottom with respect to a vehicle body80(seeFIGS. 2A, 2B, 3A and 3B) of a vehicle are simply referred to as front and rear (or longitudinal direction), left and right (or width direction), and top and bottom (or vertical direction).

The suspension10is a torsion beam suspension including a pair of left and right trailing arms12extending in the longitudinal direction of the vehicle and a torsion beam18extending in the vehicle width direction (left-right direction) and connecting the left and right trailing arms12.

A cylindrical bush14is attached to a front end of each trailing arm12. The bush14includes a cylindrical elastic member made of rubber. The inner and outer circumferential surfaces of the bush14are defined by, for example, inner and outer metal tubes.

The bush14is fitted onto the outer circumference of a shaft16defining a swing axis of the trailing arm12. This means that the bush14is interposed between the shaft16and the trailing arm12. The axis of the shaft16, or the axis of the bush14, is inclined rearward toward the outside in the vehicle width direction.

The shaft16is mounted to, for example, a support member83(seeFIGS. 3A and 3B) mounted and fixed to a rear-side frame82of the vehicle body80, and accordingly, the shaft16is supported by the vehicle body80. The shaft16corresponds to a connecting part that connects the front portion of the trailing arm12to the support member83, which can be regarded as part of the vehicle body80.

The torsion beam18is made of, for example, a steel material having an inverted U-shaped cross-section opening downward. The opposing ends of the torsion beam18are each connected to a portion of the trailing arm12located between the middle and the front end of the trailing arm12in its longitudinal direction. Since the torsion beam18is tolerant of torsion, left and right wheels (rear wheels)24(seeFIGS. 2A, 2B, 3A, and 3B) can move individually of each other in the vertical direction relative to the vehicle body80. Moreover, with the torsional stiffness of the torsion beam18, the body roll of the vehicle can be reduced.

In addition to the trailing arms12and the torsion beam18, the suspension10further includes, for each wheel24, a knuckle20that supports a hub25of the wheel24, a coil spring32interposed between the wheel24and the vehicle body80and absorbing shock applied to the wheel24, and a damper40that absorbs oscillation of the coil spring32. The damper40is disposed between the wheel24and the vehicle body80(specifically, a rear wheelhouse81which will be described later) and is configured to extend and retract in the axial direction of the damper40.

The knuckle20rotatably supports the hub25of the wheel24via a bearing26. The knuckle20is fixed to a rear portion of the trailing arm12via a bracket22.

The coil spring32is sandwiched between a lower spring seat30and an upper spring seat (not illustrated) in the vertical direction. The lower spring seat30is disposed at a corner portion between the trailing arm12and the torsion beam18. The upper spring seat is fixed to the vehicle body80. The lower spring seat30is disposed inside of the trailing arm12in the vehicle width direction and at the rear of the torsion beam18. The lower spring seat30is fixed to the trailing arm12.

The damper40is an extendable and retractable damper including a cylinder41and a piston rod42projecting downward from the cylinder41. In the present embodiment, the cylinder41of each damper40is connected to the vehicle body and the piston rod42is connected to the wheel, but the positions of the cylinder41and the piston rod42may be inverted and the piston rod42may be connected to the vehicle body and the cylinder41may be connected to the wheel.

FIGS. 2A and 2Bare schematic views illustrating the left damper40and nearby components seen from the rear.FIGS. 3A and 3Bare schematic views illustrating the left damper40and nearby components seen from inside (right side) in the vehicle width direction.FIGS. 2A and 3Aillustrate the left wheel24that has moved up (a bump stroke) relative to the vehicle body80.FIGS. 2B and 3Billustrates the left wheel24that has moved down (a rebound stroke) relative to the vehicle body80. The right damper40has the same configuration as the left damper40and thus the right damper40is not illustrated. The following mainly describes the left damper40and nearby components.

In the present embodiment, the upper end of the damper40is fixed to the rear wheelhouse81of the vehicle body80. The lower end of the damper40is connected to a rear portion of the trailing arm12via a shaft50and a pair of brackets51and52. In other words, the damper40is connected to the wheel24via the trailing arm12and the knuckle20.

The shaft50is disposed, for example, between the pair of brackets51and52that are mounted and attached to the upper surface of the trailing arm12. A cylindrical bush60is fitted onto the outer circumference of the shaft50. The bush60is attached to the lower end of the damper40. In this regard, the lower end of the damper40is pivotably supported by the shaft50via the bush60.

The bush60includes a cylindrical elastic member made of rubber. The inner and outer circumferential surfaces of the bush60are defined by, for example, inner and outer metal tubes. The elastic member may be made of an elastic material other than rubber.

As illustrated inFIGS. 2A and 2B, the axis C1of the damper40is inclined relative to the vertical direction when viewed in the vehicle's longitudinal direction. Specifically, the axis C1of the damper40is inclined inward in the vehicle width direction toward the top of the vehicle.

As illustrated inFIGS. 3A and 3B, the axis C1of the damper40is inclined relative to the vertical direction when viewed in the vehicle width direction. Specifically, the axis C1of the damper40is inclined rearward toward the top of the vehicle.

The damper40extends and retracts in the axial direction of the damper40in accordance with the stroke of the wheel24in the vertical direction relative to the vehicle body80, and the inclination angle of the axis C1of the damper40varies, accordingly.

As illustrated inFIGS. 2A and 2Billustrating, respectively, a bump state and a rebound state, the inclination angle of the axis C1of the damper40relative to the vertical direction when viewed in the vehicle's longitudinal direction increases as the wheel24strokes toward the bump side.

As illustrated inFIGS. 3A and 3Billustrating, respectively, a bump state and a rebound state, the inclination angle of the axis C1of the damper40relative to the vertical direction when viewed in the vehicle width direction increases as the wheel24strokes toward the bump side.

The axis of the shaft50that supports the lower end of the damper40agrees with the axis of the bush60fitted onto the shaft50, and the axes are hereinafter collectively referred to as an axis C2of the bush60. The axis C2of the bush60is disposed in a direction which will be described later. The direction of the axis C2of the bush60remains unchanged regardless of the strokes of the wheel. In this regard, the axis C1of the damper40and the axis C2of the bush60intersect at different angles in accordance with a bump or a rebound of the wheel24.

To prevent deformation of the bush60due to prying forces, it is preferred that the axis C1of the damper40and the axis C2of the bush60intersect at a right angle. However, the angle changes in accordance with the bump or the rebound of the wheel24, and therefore cannot be kept at the right angle all the time.

In view of this, according to the present embodiment, the axis C2of the bush60is disposed such that the angle between the axis C1of the damper40and the axis C2of the bush60is kept at, or close to, the right angle even when the wheel24bumps or rebounds. This configuration reduces deformation of the bush60due to prying forces.

Now, the disposition of the axis C2of the bush60will be described with reference toFIG. 4.

FIG. 4illustrates an imaginary first plane S1(indicated by a solid line) and an imaginary second plane S2(indicated by long-dash and double-dot line). The first plane S1is orthogonal to the axis C1of the damper40when the stroke position of the wheel24is a first position in the vertical direction relative to the vehicle body80. The second plane S2is orthogonal to the axis C1of the damper40when the stroke position of the wheel24is a second position, which is different from the first position and close to the rebound position relative to the first position.

The first plane S1and the second plane S2are located at a position in the longitudinal direction of the damper40at which the axis C2of the bush60is supposed to pass, and at which the first plane S1and the second plane S2are orthogonal to the axis C1of the damper40. The axis C2of the bush60is disposed along the line of intersection (on the line of intersection) between the first plane S1and the second plane S2. This configuration allows the axis C2of the bush60to be orthogonal to the axis C1of the damper40in both of the cases in which the wheel24is in the first position and in the second position in the vertical direction relative to the vehicle body80. This configuration substantially prevents deformation of the bush60due to prying forces. The axis C2of the bush60may be disposed along a line (on a line) parallel to the line of intersection between the first plane S1and the second plane S2.

When the wheel24is at any stroke position between the first position and the second position, the intersection angle between the axis C1of the damper40and the axis C2of the bush60is always an angle close to the right angle, which can effectively reduce deformation of the bush60due to prying forces.

In one preferred embodiment, for example, the first position is close to the bump side relative to a predetermined reference position, and the second position is close to the rebound position relative to the predetermined reference position.

The predetermined reference position is, for example, a position of the wheel when the vehicle stopping on a horizontal road surface carries a predetermined amount of load. The predetermined amount of load is, for example, a load of the vehicle carrying no person or no cargo, but with a full fuel tank.

Setting the first position and the second position to such positions as described above allows the axis C1of the damper40to be orthogonal to the axis C2of the bush60when the wheel is in the first position close to the bump position relative to the predetermined reference position and when the wheel is in the second position close to the rebound position relative to the predetermined reference position. It is therefore possible to substantially prevent deformation of the bush60due to prying forces. In addition, the deformation of the bush60due to prying forces is effectively reduced when the wheel24bumps and rebounds while the vehicle is running. In this regard, the damper40operates smoothly, thereby providing good ride comfort and good handling stability of the vehicle.

The first position is close to the bump side relative to the predetermined reference position, and the second position is close to the rebound position relative to the predetermined reference position. More specifically, the first position and the second position are located, for example, at the following positions.

The first position may be a position at the time when two people having a certain weight are seated in the front seats (the driver's seat and the passenger seat) of the vehicle stopping on a horizontal road surface. This configuration substantially reduces deformation of the bush60due to prying forces when a driver and a passenger are seated in the front seats of the vehicle, which is a situation typically and highly frequently seen in a vehicle. This configuration can provide a better ride comfort and handling stability of the vehicle.

In another example, the first position may be a position in which the damper40is most retracted (a position closest to the bump side). In this case, when the wheel's stroke position is closest to the bump side, the axis C1of the damper40is orthogonal to the axis C2of the bush60. Moreover, when the wheel is at any stroke position between the predetermined reference position and the first position (that is, at any stroke position in the entire range of the wheel stroke from the reference position to the position closest to the bump side), the intersection angle between the axis C1of the damper40and the axis C2of the bush60is always an angle close to the right angle. This configuration can effectively reduce deformation of the bush60due to prying forces when the wheel24bumps.

In still another example, the first position may be a position at the time when the vehicle stopping on a horizontal road surface carries the maximum number of passengers having a certain weight. In this case, when the vehicle carries the maximum number of passengers, which means that the wheel's stroke position is at a bump position, the axis C1of the damper40is orthogonal to the axis C2of the bush60. Moreover, when the wheel is in any other positions close to this bump position, the intersection angle between the axis C1of the damper40and the axis C2of the bush60is always close to the right angle. This configuration can effectively reduce deformation of the bush60due to prying forces when the wheel24bumps.

In yet another example, the first position may be a position at the time when the vehicle stopping on a horizontal road surface carries the maximum load. When the vehicle carries the maximum load, which means that the wheel's stroke position is at a bump position, the axis C1of the damper40is orthogonal to the axis C2of the bush60. Moreover, when the wheel is in any other positions close to this bump position, the intersection angle between the axis C1of the damper40and the axis C2of the bush60is always close to the right angle. This configuration can effectively prevent deformation of the bush60due to prying forces when the wheel24bumps.

The second position, which is close to the rebound side relative to the predetermined reference position, may be a position in which the damper40is most extended (a position closest to the rebound side). In this case, when the wheel's stroke position is closest to the rebound side, the axis C1of the damper40is orthogonal to the axis C2of the bush60. Moreover, when the wheel is at any stroke position between the predetermined reference position and the second position (that is, at any stroke position in the entire range of the wheel stroke from the reference position to the position closest to the rebound side), the intersection angle between the axis C1of the damper40and the axis C2of the bush60is always close to the right angle. This configuration can effectively reduce deformation of the bush60due to prying forces when the wheel24rebounds.

FIGS. 5A and 5Billustrate a procedure of mounting the suspension10in a vehicle production process. The second position which may prevent deformation of the bush60due to prying forces can be determined in this mounting procedure.

Specifically, as illustrated inFIG. 5A, an assembly90, which is an integrated part of the left and right trailing arms12, the torsion beam18, and the left and right knuckles20, is placed on a lift100. The lift100is raised to bring the assembly90closer to the left and right dampers40and the bushes60, which have already been mounted to the vehicle body80.

At this moment, the dampers40hanging from the vehicle body80are most extended because of, for example, the weight of the piston rod42and the pressure of the gas inside the cylinder41.

Subsequently, although not illustrated inFIGS. 5A and 5B, the bushes14attached to the front ends of the trailing arms12are mounted to the vehicle body80(to the support members83mounted and fixed to the rear-side frame82) via the shafts16.

Next, as illustrated inFIG. 5B, the bushes60attached to the lower ends of the dampers40are mounted to the respective pairs of brackets51and52attached to the trailing arms12. In this procedure, the shaft50is inserted in holes of the pair of brackets51and52and a hole formed in the center of the bush60, and the shaft50is fixed thereto, without causing any deformation of the bush60due to prying forces. To fix the shaft50, for example, a bolt is used as the shaft50and a nut is tightened onto an end screw portion of the shaft50.

The suspension10is assembled in accordance with the procedure described above, and the second position which may prevent deformation of the bush60due to prying forces can be determined in this mounting procedure.

In the present embodiment, the axis C2of the bush60is disposed relative to the axis C1of the damper40as described above and, as illustrated inFIGS. 2A and 2B, the axis C2of the bush60is inclined downward toward the inside in the vehicle width direction when viewed in the longitudinal direction. As illustrated inFIG. 6, the axis C2of the bush60is inclined frontward toward the inside in the vehicle width direction when viewed in the vertical direction.

Disposing the axis C2of the bush60as described above can effectively reduce the deformation of the bush60due to prying forces regardless of the stroke position of the wheel24in the vertical direction relative to the vehicle body80. Moreover, such disposition can substantially prevent greater torsion, compared to torsion in a conventional case, from occurring in the bush60. Preventing the torsion in the bush60can effectively reduce an increase in friction in the damper40caused by the reaction force of the bush60. In this regard, the damper40can operate smoothly, thereby providing a better ride comfort and handling stability of the vehicle.

According to the present embodiment, disposing the axis C2of the bush60as described above can effectively reduce deformation of the bush60due to prying forces, and can also dispose the damper40so as to be inclined inward in the vehicle width direction toward the top of the vehicle. This disposition can substantially prevent the damper40from contacting the wheel24(tire) and can dispose the lower end of the damper40close to the hub25of the wheel24in the vehicle width direction. This configuration facilitates reducing a moment about an axis extending in the longitudinal direction though the lower end of the damper40when a load is applied from the road surface to the hub25of the wheel24. Such reduction in the moment can reduce bending of the torsion beam18caused by the moment and can reduce the possibility of damage to the torsion beam18.

The present invention is not limited to the above-described embodiment and various modifications can be made without departing from the scope of the invention as defined by the appended claims.

In the above-described embodiment, for example, the axis C1of the damper40is inclined inward in the vehicle width direction toward the top of the vehicle, but as illustrated inFIGS. 7A and 7B, the axis C1of the damper40may be inclined outward in the vehicle width direction toward the top of the vehicle, when viewed in the longitudinal direction.

In this case, in a condition in which the axis C1of the damper40is inclined rearward toward the top of the vehicle when viewed in the vehicle width direction as in the above embodiment (seeFIGS. 3A and 3B), the axis C2of the bush60, which is disposed along the line of intersection between the imaginary first plane S1and the imaginary second plane S2as in the above embodiment, is inclined upward toward the inside the vehicle width direction as illustrated inFIGS. 7A and 7Bwhen viewed in the longitudinal direction, and is inclined rearward toward the inside in the vehicle width direction as illustrated inFIG. 8when viewed in the vertical direction.

Similarly to the above embodiment, this configuration too can effectively reduce deformation of the bush60due to prying forces regardless of the stroke position of the wheel24in the vertical direction relative to the vehicle body80. Preventing deformation of the bush60due to prying forces can in turn effectively reduce an increase in friction in the damper40caused by the reaction force of the bush60and thus the damper40can operate smoothly.

In the above embodiment, the axis C1of the damper40is inclined rearward toward the top of the vehicle, but the present invention is also applicable to a case in which the axis C1of the damper40is inclined frontward toward the top of the vehicle.

In the above embodiment, the shaft16defining the swing axis of the trailing arm12is located in front of the bush60, but the present invention is also applicable to a case in which the swing axis of the trailing arm12is located at the rear of the bush60.

In the above embodiment, the bush60is interposed between the lower end of the damper40and the shaft50, and disposition of the axis C2of the bush60has been described. If the bush is interposed between the upper end of the damper40and a shaft that pivotably supports the upper end, the axis of the bush can be disposed in the same manner as the embodiment of the present invention and this can effectively reduce deformation of the bush due to prying forces.

In the above embodiment, a torsion beam suspension has been described as an example of the suspension device for vehicles, but the present invention is applicable to any suspension device including a damper at least an end of which is supported by a shaft via a bush.

Moreover, the present invention is applicable not only to the rear suspension for the rear wheels, but also to a front suspension for front wheels.

The above embodiment is presented for illustrative purposes only and is not intended to limit the scope of the present invention. The scope of the present invention is defined by the appended claims, and changes or modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

INDUSTRIAL APPLICABILITY

The present invention is applicable to a suspension device for vehicles including a damper an end of which is supported by a shaft via a bush.

DESCRIPTION OF REFERENCE CHARACTERS