JP2012116483A - Suspension device for rear wheel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension for rear wheels which can reduce vibration transmitted to a vehicle body, while maintaining driving stability.SOLUTION: Two lower links for connecting a lower region of a wheel support member and a vehicle body side member by an elastic bush are arranged in line in a vehicle front and rear direction, and the two lower links are connected by the elastic bush. As the elastic bush for connecting the lower links, a bush with low rigidity is used in a low frequency region, and a bush with high rigidity is used in a high frequency region. As an elastic bush for connecting a lower region of the wheel support member and the vehicle body side member, and the lower links, a bush with higher rigidity than the elastic bush for connecting the lower links is used in the lower frequency region.

Description

  The present invention relates to a suspension device for a rear wheel used in a vehicle.

As a conventional rear wheel suspension device, for example, there is a device described in Patent Document 1. In this apparatus, the lower region of the wheel support member and the vehicle body side member are connected to each other, and the pair of rigid arms arranged at intervals in the vehicle front-rear direction and the pair of rigid arms are respectively rigidly connected to the pair of rigid arms. And a coupling member constructed between the rigid arms.
Further, the wheel support member, the vehicle body side member, and the end of each rigid arm can be moved up and down by being slidably connected by an elastic bush.

JP 62-234705 A

However, the elastic bushing that connects the wheel support member, the vehicle body side member, and the end of each rigid arm is located on the vibration transmission path from the road surface to the vehicle body. If a member with high dynamic rigidity, such as a rubber material with high damping characteristics, is used as the elastic bush for the purpose of securing, etc., it becomes easier to transmit the vibration input from the road surface to the vehicle body, and road noise that is noise at high frequency May not be reduced.
The present invention focuses on the above points, and an object of the present invention is to provide a rear wheel suspension capable of reducing vibration transmitted to the vehicle body while ensuring steering stability.

  In order to solve the above-described problems, the present invention is configured such that two lower links that connect the lower region of the wheel support member and the vehicle body side member with an elastic bush are arranged side by side in the vehicle front-rear direction, and the two As the elastic bush that connects the lower links with elastic bushes and connects the lower links with each other, a bush that is low in the low frequency region and high in rigidity in the high frequency region is used. As the elastic bush for connecting the link, a bush having higher rigidity than the elastic bush for connecting the lower links is used in the low frequency region.

  ADVANTAGE OF THE INVENTION According to this invention, the suspension for rear-wheels which can reduce the vibration transmitted to a vehicle body can be provided, ensuring steering stability.

It is a top view which shows the suspension apparatus for rear wheels which concerns on 1st Embodiment based on this invention. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic diagram seen from the vehicle front which shows the arrangement configuration of the link in the suspension apparatus for rear wheels which concerns on 1st Embodiment based on this invention. It is a figure which shows the example of the rigidity characteristic of an elastic bush. It is a top view which shows the behavior with respect to the input to a vehicle front-back direction. It is a top view which shows another suspension apparatus for rear wheels which concerns on 1st Embodiment based on this invention. It is sectional drawing which shows the connect bush which concerns on 2nd Embodiment based on this invention. It is a top view explaining the suspension device for rear wheels concerning a 2nd embodiment based on the present invention. It is a figure which shows the example of the rigidity characteristic of an elastic bush.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a top view showing a suspension device for a rear wheel according to the present embodiment, and FIG. 2 is a schematic diagram for explaining the arrangement of links as viewed from the front of the vehicle.
(Constitution)
Two lower links 4 and 5 that connect the lower region of the axle 2 that rotatably supports the wheel 1 and the suspension member 3 that is a vehicle body side member, and the upper region of the axle 2 and the suspension member 3 are connected. The upper link 8 is provided.

  The two lower links 4 and 5 are attached to the axle 2 so as to be vertically swingable by one elastic bushes 9 and 10, respectively, and one elastic bush 11 and one to the suspension member 3, respectively. 12 is connected in a state in which it can swing up and down. The upper link 8 is also attached to the axle 2 so as to be vertically swingable by one elastic bush 13 and is also connected to the suspension member 3 so as to be vertically swingable by one elastic bush 14. Yes.

The two lower links 4, 5 are arranged so as to be aligned in the vehicle front-rear direction. Here, when the two lower links 4 and 5 are described separately, the lower link 4 on the front side in the vehicle longitudinal direction is the front lower link 4 and the lower link 5 on the rear side in the vehicle longitudinal direction is the rear lower link. Let's call it 5.
Each of the elastic bushes 9 to 14 is configured such that an elastic body made of a rubber body is interposed between an outer cylinder and an inner cylinder arranged in a nested manner. In the present embodiment, the outer cylinder side is fixed to the ends of the links 4, 5, and 8, and the inner cylinder side is attached to the suspension member 3 or the axle 2 via bolts.

The front lower link 4 is a rod-like member extending linearly along the link axis L1, and the elastic bushes 9 and 11 having the above-described configuration are provided at both end attachment portions thereof.
The rear lower link 5 is integrated with the link main body portion 6 extending along the link axis L2 and the link main body portion 6 and is connected to the front lower link 4 from the link main body portion 6 toward the front lower link 4. It is comprised from the overhang | projection part 7 projected to the direction front. In this embodiment, the overhang portion 7 is a plate-like member and has a substantially trapezoidal shape when viewed from above. But the overhang | projection part 7 does not need to be a plate-shaped member, and if it protrudes toward the front side lower link 4 from the link main-body part 6, the structure will not be ask | required.

  A tip portion of the overhanging portion 7 facing the front lower link 4 in the vehicle front-rear direction is connected to the front lower link 4 via two elastic bushings 20 and 21 arranged offset in the vehicle width direction. Yes. In the present embodiment, the elastic bushes 20 and 21 that connect the front lower link 4 and the overhanging portion 7 are arranged with the bush axis substantially in the vehicle front-rear direction (a direction perpendicular to the link axis L1) in a top view. Thus, the outer cylinder is fixed to the front lower link 4 and the inner cylinder is fixed to the overhanging portion 7 via a mounting bolt. As a result, the front lower link 4 and the rear lower link 5 are connected in a three-dimensional manner so as to be swingable by the elastic bushes 20 and 21 as connecting portions, and the swing amount is also between the outer cylinder and the inner cylinder. It is regulated by the span and the rigidity of the elastic body.

  Further, in the present embodiment, in the top view, the span in the vehicle front-rear direction between the attachment points of the two lower links 4 and 5 to the suspension member 3 (hereinafter simply referred to as vehicle body attachment points P1 and P3). Also, the two lower links 4, 5 are arranged so that the span in the vehicle front-rear direction between the attachment points to the axle 2 (hereinafter simply referred to as wheel-side attachment points P2, P4) is shorter. Yes. That is, in the top view, the intersection P5 between the link axis lines L1 and L2 connecting the wheel side attachment points P2 and P4 and the vehicle body side attachment points P1 and P3 in the two lower links 4 and 5 is from the axle 2. Is also set to be outward in the vehicle width direction, that is, outward in the vehicle width direction from the wheel side attachment points P2 and P4 of the lower links 4 and 5. In the example of FIG. 1, the front lower link 4 is larger than the offset amount (substantially zero in FIG. 1) of the wheel side attachment point P4 with respect to the vehicle body side attachment point P3 in the rear lower link 5 with respect to the vehicle side attachment point P3. So that the offset amount of the wheel side attachment point P2 in the vehicle longitudinal direction rearward relative to the vehicle body side attachment point P1 is larger than the inclination of the link axis L2 of the rear lower link 5 in the vehicle longitudinal direction rearward in the top view. The inclination of the link axis L1 of the front lower link 4 to the rear in the vehicle front-rear direction is set large. By arranging in this manner, the shape connecting the four wheel side attachment points P2, P4 and the vehicle body side attachment points P1, P3 of the two lower links 4, 5 becomes a substantially trapezoidal shape in a top view. ing.

Further, as compared with the rear lower link 5, the front lower link 4 is set so that the wheel side attachment points P2, P4 with respect to the vehicle body side attachment points P1, P3 are largely offset rearward in the vehicle longitudinal direction. The intersection P5 of the two link axes L1 and L2 of the two lower links 4 and 5 is disposed behind the center of the wheel 1 (wheel center W / C) in the vehicle front-rear direction when viewed from above.
Here, the elastic bushes 20 and 21 constituting the connecting portion for connecting the front lower link 4 and the overhanging portion 7 so as to be swingable are referred to as connect bushes 20 and 21, and the lower links 4 and 5 and the axle 2 and The elastic bushes 9 to 12 that connect the suspension member 3 are called mounting bushes 9 to 12.

In this embodiment, the static stiffness of at least one of the connect bushes 20 and 21 is As, the dynamic stiffness in a high frequency region where road noise is generated is Ad, and the static stiffness of the mounting bushes 9 to 12 is Bs. When the dynamic stiffness in the high frequency region where road noise occurs is defined as Bd,
An elastic bushing that satisfies the following formula (1) is used. In addition, when satisfy | filling (1) Formula only about one of the connection bushes 20 and 21, it is preferable to employ | adopt as the connection bush 20 of the wheel side with comparatively large rocking | fluctuation.
(As / Bs) <(Ad / Bd) (1)

For example, as shown in FIG. 3, the rigidity characteristics of the bush are low as compared to the static rigidity and the input in a low frequency region of 25 Hz or less as the connect bushes 20 and 21, and the rigidity increases as the input frequency increases. An elastic body is used that has a high characteristic, that is, it is soft for input in the low frequency region and has hard characteristics for input in the high frequency region (characteristic B1 in FIG. 3).
Further, the mounting bushes 9 to 12 have high rigidity with respect to input in the static rigidity and a low frequency region of 25 Hz or less (hereinafter also referred to as a riding comfort region), and the rigidity does not increase so much even when the input frequency is increased. Alternatively, an elastic body having a characteristic whose gradient is lower than the gradient of rigidity of the connect bush is configured (characteristic B2 in FIG. 3).
With this setting, the above equation (1) is satisfied.

Specifically, in order to satisfy the condition of the above formula (1), for example, as an elastic body of the connect bush, a general rubber compounded with carbon, mica (mica) or the like is used. The same material is used as the elastic body of the mounting bush.
Here, in the high-frequency region where road noise occurs (road noise region), the equation (1) is satisfied even if the dynamic stiffness of the mounting bushes 9 to 12 is lower than the dynamic stiffness of the connect bushes 20 and 21.

Road noise is noise generated by the road surface and tires during travel. For example, fine vibrations are generated in the tire due to road surface irregularities, which are transmitted to the vehicle body via the suspension, and the vibrations become noise.
In addition, although the frequency band of the high frequency area | region of a road noise area changes with vehicles, generally a lower limit is 50-80 Hz and an upper limit is 400-800 Hz. In general, the peak frequency band of road noise is 125 to 200 Hz.

Preferably, the mounting bushes 9 to 12 are hard (high rigidity) and the connection bushes 20 and 21 are soft (low rigidity) for the input of the static rigidity and the riding comfort area which is a low frequency area. In the road noise region which is set to be large and is a high frequency region, the rigidity of the connect bushes 20 and 21 is preferably hard.
Here, the axle 2 constitutes a wheel support member, and the suspension member 3 constitutes a vehicle body side member.

(Function and effect)
(1) By connecting the two lower links 4 and 5 to each other, the vehicle front-rear direction input to the wheel 1 can be received by the two lower links 4 and 5. For this reason, in order to receive the said vehicle front-back direction input, it is not necessary to provide another link.
Further, even if the two lower links 4 and 5 are connected to each other in this way, the connecting portion is configured to be swingable only within a predetermined swing range by the connect bushes 20 and 21, so that the wheel 1 can be connected. Connect bushes 20 and 21 are connected to each other in such a manner that they can swing at least within a predetermined swing range in the vehicle width direction.

  As a result, the elastic bodies of the connection bushes 20 and 21 constituting the connecting portion are bent with respect to the front-rear direction input to the wheel 1 (front-rear input to the wheel center W / C) due to road surface irregularities. As shown in FIG. 2, the connect bushes 20 and 21 are two in the top view by oscillating and displacing in the vehicle width direction while the inner cylinder oscillates somewhat in the vehicle longitudinal direction relative to the outer cylinder. The substantially trapezoidal shape connecting the four wheel side attachment points P2 and P4 and the vehicle body side attachment points P1 and P3 of the lower links 4 and 5 is changed and is supported by the two lower links 4 and 5 connected to each other. The rigidity of the axle 2 in the vehicle front-rear direction is set low. For this reason, the ride comfort is improved, in particular, the shock when riding over the protrusion is reduced.

In addition, since the connection bushes 20 and 21 are absorbed by bending with respect to the input in the front-rear direction, and attenuation is also obtained by the characteristics of the rubber of the connect bushes 20 and 21, the vibration of the front-rear direction input is good.
In particular, in the present embodiment, the rigidity of the connection bushes 20 and 21 is low with respect to the input in the low frequency region such as when overhanging a protrusion, so that the connection bushes 20 and 21 are in the vertical direction and the horizontal direction (vehicle width direction or As a result of absorbing vibration by oscillating and displacing in the direction of the link axis L1 of the front lower link 4, as described above, the vibration in response to the longitudinal input to the wheel (the longitudinal input to the wheel center at a low frequency) Good fit and reduced shock when overhanging protrusions as described above.

Here, with regard to the swinging of the connection bushes 20 and 21 when the protrusions are overridden, the torsional displacement mainly occurs in the wheel-side connect bushing 20 in the vertical direction, and both the connection bushings with respect to the shearing. Oscillating displacements in the left-right direction are generated at 20 and 21 to absorb the vibration. For this reason, if the above equation (1) holds for the rigidity of at least the vertical direction and the horizontal direction (the vehicle width direction or the link axis L1 direction of the front lower link 4) of the rigidity of the connect bushes 20 and 21, This effect can be exhibited.
As described above, even if the lower links 4 and 5 are designed so as to satisfy the strength, the rigidity in the front-rear direction is determined by the rigidity of the connect bushes 20 and 21, so that the degree of freedom in design can be increased.

(2) Since the rigidity of the input and output in the front and rear direction can be set low by bending the connection bushes 20 and 21 with respect to the input and output from the front and rear direction to the wheel 1 in this way, the two lower links 4 and 5 are connected. Even if the two lower links 4 and 5 receive the longitudinal input to the wheel 1, in order to reduce the shock due to road surface irregularities, the wheel side attachment points P2 of the two lower links 4 and 5 There is no need to set the rigidity of the mounting bushes 9 to 12 constituting the P4 and the vehicle body side mounting points P1 and P3 low. In this embodiment, since the rigidity of the mounting bushes 9 to 12 of the lower links 4 and 5 is set high, the lateral rigidity (rigidity in the vehicle width direction) of the axle 2 can be increased. This leads to an increase in camber rigidity, and as a result, steering stability can be improved. In addition, since the lateral direction input to the wheel 1 is applied to the two lower links 4 and 5 substantially in the direction of the link axes L1 and L2, the lateral rigidity of the axle 2 is set even if the rigidity of the connect bushes 20 and 21 is set low. Never lower. As a result, it is possible to achieve both a low rigidity in the front-rear direction and a high rigidity in the lateral direction, and it is possible to achieve a higher level of riding comfort and handling stability.

(3) As described above, the rigidity of the suspensions in the front-rear direction is determined by the rigidity of the connection bushes 20 and 21, but the high-frequency vibration input in the road noise region is caused by a relatively small input due to road surface unevenness or tire patterns. On the other hand, since the rigidity of the connect bushes 20 and 21 is high, the swing between the two lower links 4 and 5 is suppressed, that is, the mode in which the lower links 4 and 5 are loosely separated from each other is suppressed. As a result, the transmission power of road noise is reduced, and a noise suppression effect against road noise is obtained.

(4) Further, in the top view, the intersection P5 of the link axes L1 and L2 of the two lower links 4 and 5 is positioned rearward in the vehicle front-rear direction from the center of the wheel 1 (wheel center W / C). The rotation center of the axle 2 is located behind the wheel center W / C. For this reason, with respect to the input in the tire lateral direction at the time of turning of the vehicle, a torque for directing the wheel 1 on the turning outer wheel side in the toe-in direction works, and stability at the time of turning of the vehicle is improved.

(5) In addition, when viewed from above, the intersection P5 of the link axis lines L1 and L2 of the two lower links 4 and 5 connected to each other is attached to the wheel side outside the axle 2 in the vehicle width direction, that is, in the vehicle longitudinal direction. By setting the span between the points P2 and P4 to be narrower than the span between the vehicle body side attachment points P1 and P3, the following operational effects can be obtained.
When there is an input in the vehicle longitudinal direction rearward with respect to the ground contact surface of the wheel 1 due to braking or the like, the wheel side attachment points P2, P4 of the two lower links 4, 5 are both substantially the same amount rearward in the vehicle longitudinal direction. Although the rocking displacement occurs, a toe change in the toe-in direction is caused by a difference in vehicle lateral displacement of the wheel side attachment points P2 and P4 of the two lower links 4 and 5, and the stability during braking is improved.

In the example of FIG. 1, the rear lower link 5 has a link axis L2 set substantially in the vehicle width direction, but the front lower link 4 has a link axis L1 in the vehicle longitudinal direction so that the wheel 1 side is rearward in the vehicle longitudinal direction. As a result of tilting backward in the front-rear direction, the wheel side attachment points P2, P4 of the two lower links 4, 5 both swing and displace by substantially the same amount rearward in the vehicle front-rear direction, but on the wheel side of the rear lower link 5 The wheel 1 changes in the toe-in direction when the wheel side attachment point P2 of the front lower link 4 is drawn to the vehicle side from the attachment point P4.
(6) As described above, at least, it is possible to achieve both improvement in riding comfort and improvement in steering stability and reduction in vibration.

(application)
(1) In the above embodiment, the case where the upper link 8 is constituted by one bar-like link is illustrated, but there may be two or more, or other shapes such as an A-arm.
(2) Further, as shown in FIG. 5, the lower links 4, 5 may be connected via the connection bushes 20, 21 on the link axis L <b> 2 side of the rear lower link 5.
Further, the connection bushes 20 and 21 that connect the two lower links 4 and 5 do not have to be disposed on the link axes L1 and L2 of the lower links 4 and 5, for example, between the two lower links 4 and 5. You may arrange | position with respect to a position.

Alternatively, the projecting portions 7 are individually projected from the lower links 4 and 5 toward the other link, and one connecting portion is set on the axis of each lower link 4 and 5. You may arrange | position the said connection bushes 20 and 21 to a connection part, respectively.
Even in this case, it is preferable that the two connect bushes be offset in the vehicle width direction when viewed from the front of the vehicle. In one connect bush, it is necessary to devise such as increasing the size in order to greatly increase the rigidity in the road noise region.

(3) Further, the connect bush to which the two lower links 4 and 5 are connected is not limited to two locations, and may be three or more locations.
(4) In the above embodiment, the two lower links 4 are arranged by arranging the link axis L2 of the rear lower link 5 in the vehicle width direction and tilting the link axis L1 of the front lower link 4 rearward in the vehicle front-rear direction. The intersection point P5 of the five link axis lines L1 and L2 is set to be outward in the vehicle width direction from the axle 2, but is not limited thereto. For example, the link axis L1 of the front lower link 4 is arranged substantially in the vehicle width direction and the link axis L2 of the rear lower link 5 is arranged such that the wheel side attachment point P4 is closer to the front side in the vehicle longitudinal direction than the vehicle body side attachment point P3. In addition, the intersection P5 of the link axes L1 and L2 of the two lower links 4 and 5 may be set to be more outward in the vehicle width direction than the axle 2 by inclining to the front side.

(5) Moreover, in the said embodiment, although it arrange | positions so that the axis | shaft of the connect bushes 20 and 21 may face the substantially vehicle front-back direction (direction orthogonal to link axial property), it is not limited to this. For example, the shafts of the connect bushes 20 and 21 may be arranged along the vehicle width direction and the link axis lines L1 and L2. However, it is easier to adjust the rigidity of the bush in the up-down direction and the left-right direction when the bush axis is directed in the direction orthogonal to the link axis or in the vehicle longitudinal direction.
(6) The spans of the attachment points P1 and P3 in the vehicle front-rear direction and the attachment points P2 and P4 may be equal, that is, the two lower links 4 and 5 may be arranged in parallel.

(Second Embodiment)
Next, a second embodiment according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected and demonstrated about the member similar to the said embodiment.
The basic configuration of this embodiment is the same as that of the first embodiment, but the configuration of the connect bushes 20 and 21 is characteristic.
That is, in this embodiment, fluid-filled bushes in which a magnetic fluid is sealed as shown in FIG. The bush has an elastic body 21c and liquid chambers 21d and 21e interposed between the outer cylinder 21a and the inner cylinder 21b, and stores the magnetic fluid in the liquid chambers 21d and 21e and extends in the circumferential direction. By forming the orifice 21f in the bush, it is possible to change the bush rigidity, particularly the rigidity in the axial direction, by changing the viscosity (resistance) of the magnetic fluid.

In addition, a magnetic force generator (not shown) is installed in the vicinity of the connect bush. When the magnetic fluid receives the magnetic force generated by the magnetic force generator, the viscosity of the magnetic fluid is changed and passes through the orifice. The resistance to be changed.
Further, a frequency detection means for detecting a vibration frequency generated in the suspension is provided. The frequency detection means includes, for example, a speed sensor attached to the lower links 4 and 5 and the axle 2, an acceleration sensor, or a gap sensor (relative displacement meter) attached in the vicinity of the connect bushes 20 and 21. In FIG. 7, the case where the above sensors 30 are provided in the axle 2 is illustrated. The sensor 30 outputs a detection signal to the controller 31.

Further, the controller 31 receives a signal from the sensor 30, and a lower link that is a suspension member based on signals from the sensor 30 such as vibration speed information, acceleration information, and relative displacement information, which are information of the signal. When the vibration frequency occurring in 4 and 5 is calculated and determined to be a predetermined frequency, for example, a frequency of a predetermined frequency or higher, for example, a frequency of 40 Hz or higher (a frequency slightly smaller than the high frequency band of the road noise region), By changing the magnetic force (not shown) and increasing the viscosity of the magnetic fluid, the connection bushes 20 and 21 are set in a high rigidity state. That is, the rigidity of the connect bushes 20 and 21 is dynamically switched as shown in FIG. 8 according to the vibration frequency generated in the suspension or wheel.
Other configurations are the same as those in the first embodiment.
With respect to the function and effect, the same function and effect as the first embodiment are achieved.

1 wheel 2 axle (wheel support member)
3 Suspension member (vehicle body side member)
4 Front Lower Link 5 Rear Lower Link 6 Link Body 7 Overhang 8 Upper Links 9-12 Mounting Bushings 20, 21 Connect Bush 21a Outer Cylinder 21b Inner Cylinder 21c Elastic Body 21d, 21e Liquid Chamber 21f Enclosed with Magnetic Fluid Orifice 30 Sensor 31 Controller L1, L2 Link axis

In order to solve the above-described problems, the present invention is configured such that two lower links that connect the lower region of the wheel support member and the vehicle body side member with an elastic bush are arranged side by side in the vehicle front-rear direction, and the two the lower link together, linked via a separate elastic bushing at two or more locations spaced apart in the vehicle width direction, the rigidity of the elastic bushes connecting the lower link to each other, and the lower region and the vehicle body-side member of the vehicle wheel support member Lower than the rigidity of the elastic bush connecting the lower link.

Claims (4)

In the rear wheel suspension apparatus in which two lower links that connect the lower region of the wheel support member that rotatably supports the wheel and the vehicle body side member via elastic bushes are arranged side by side in the vehicle longitudinal direction,
The two lower links are connected via one or more elastic bushings,
The static rigidity of at least one elastic bush connecting the two lower links is As, and the dynamic rigidity in a high frequency region where road noise occurs is Ad.
When the static stiffness of the elastic bush that connects the wheel support member and the vehicle body side member and the lower link is defined as Bs and the dynamic stiffness in the high frequency region where road noise is generated is defined as Bd,
A suspension device for a rear wheel using an elastic bushing that satisfies the following formula (1).
(As / Bs) <(Ad / Bd) (1) In the rear wheel suspension apparatus in which two lower links that connect the lower region of the wheel support member that rotatably supports the wheel and the vehicle body side member via elastic bushes are arranged side by side in the vehicle longitudinal direction,
Connect the two lower links with one or more elastic bushings,
As the at least one elastic bush that connects the lower links, a bush that has relatively low rigidity in the low-frequency region that is generated by the impact of riding over the protrusion of the wheel and high rigidity in the high-frequency region that generates road noise is used. In addition, as an elastic bush that connects the lower region of the wheel support member and the vehicle body side member and the lower link, a rear wheel that uses a bush having higher rigidity than the elastic bush that connects the lower links in the low frequency region. Suspension device.   The rear wheel suspension device according to claim 1 or 2, wherein two or more elastic bushes for connecting the two lower links are offset in the vehicle width direction.   The elastic bush that connects the two lower links is configured by a fluid-filled bush, and the viscosity of the fluid sealed in the fluid-filled bush is changed according to the vibration frequency input to the lower link, thereby The suspension device for a rear wheel according to any one of claims 1 to 3, wherein the rigidity of an elastic bush connecting the lower links is adjusted.

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