Rear suspension device

Abstract

A rear suspension device (1) couples a vehicle wheel (3) and a vehicle body (2) by means of: a first upper link (11) and a second upper link (12); a first lower link (13); and a second lower link (14) and a third lower link (15). The rigidity of the first upper link (11) and the rigidity of the second upper link (12) are different. The rigidity of the second upper link (12) having a relatively large inclination angle (θ2) with respect to a vehicle width direction in a vehicle plan view is lower than the rigidity of the first upper link (11) having a relatively small inclination angle (θ1) with respect to the vehicle width direction in the vehicle plan view. In a case where the inclination angles (θ1, θ2) of the upper links with respect to the vehicle width direction are identical, the rigidity of the second upper link (12) having a relatively long distance (L2) from a vehicle axle (32) in the vehicle plan view is lower than the rigidity of the first upper link (11) having a relatively short distance (L1) from the vehicle axle (32) in the vehicle plan view.

Description

Rear suspension device

[0001] The present invention relates to a rear suspension system for an automobile.

[0002] A known conventional multi-link rear suspension device includes an A-type upper link and three lower links (see Patent Document 1).

[0003] Patent No. 4195208

[0004] It is desirable for a rear suspension system to have high rigidity in the vehicle width direction to improve cornering response, while having low rigidity in the vehicle's longitudinal direction to reduce shock when going over bumps. However, the A-type upper link of the above-mentioned conventional technology has the problem that it is difficult to set low rigidity in the longitudinal direction of the vehicle.

[0005] The problem to be solved by the present invention is to provide a rear suspension device that can set high rigidity in the vehicle width direction, while setting low rigidity in the vehicle front-rear direction.

[0006] The present invention solves the above-mentioned problems in a rear suspension device that connects a wheel and a vehicle body with two upper links and a plurality of lower links by making the rigidity of the two upper links different.

[0007] According to the present invention, since the two upper links have different rigidities, the rigidity in the vehicle width direction can be set high, while the rigidity in the vehicle front-rear direction can be set low.

[0008] 3A is a perspective view showing a rear suspension device according to a first embodiment of the present invention. FIG. 3B is a plan view of the rear suspension device of FIG. 1, as seen from above the vehicle. FIG. 3C is a side view of the rear suspension device of FIG. 1, as seen from the side of the vehicle. FIG. 3D is a rear view of the rear suspension device of FIG. 1, as seen from the rear of the vehicle. FIG. 3E is a plan view schematically showing an upper link of the rear suspension device of FIG. 3A. FIG. 3F is a plan view schematically showing a lower link of the rear suspension device of FIG. 1. FIG. 3G is a plan view schematically showing an upper link of another example of the rear suspension device of FIG. 1. FIG. 3H is a rear view of FIG. 3A. FIG. 3I is a perspective view of a rear suspension device according to a second embodiment of the present invention. FIG. 3I is a plan view of the rear suspension device of FIG. 4, as seen from above the vehicle. FIG. 3I is a side view of the rear suspension device of FIG. 4, as seen from the side of the vehicle. FIG. 3I is a rear view of the rear suspension device of FIG. 4, as seen from the rear of the vehicle. FIG. 3I is a plan view schematically showing an upper link of the rear suspension device of FIG. 4. FIG. 3I is a plan view schematically showing a lower link of the rear suspension device of FIG. 4. FIG. 3I is a perspective view of a rear suspension device according to a third embodiment of the present invention. FIG. 7 is a plan view of the rear suspension device of FIG. 7, as seen from above the vehicle. Fig. 8 is a side view of the rear suspension device of Fig. 7 as seen from the side of the vehicle. Fig. 9 is a rear view of the rear suspension device of Fig. 7 as seen from the rear of the vehicle. Fig. 10 is a plan view schematically showing an upper link of the rear suspension device of Fig. 7. Fig. 11 is a plan view schematically showing a lower link of the rear suspension device of Fig. 7.

[0009] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The rear suspension system according to the present invention is a so-called independent suspension system that can raise and lower left and right wheels independently, and is also a so-called multi-link suspension system that includes multiple links. In the following embodiments, the present invention will be described using a rear suspension system suspended between the left rear wheel and the vehicle body as an example, but a rear suspension system suspended between the right rear wheel and the vehicle body can also be configured in the same way.

[0010] <<First Embodiment>> Figure 1 is a perspective view showing a rear suspension device 1 according to a first embodiment of the present invention, Figure 2A is a plan view of the rear suspension device 1 of Figure 1 as seen from above the vehicle, Figure 2B is a side view of the rear suspension device 1 of Figure 1 as seen from the side of the vehicle, and Figure 2C is a rear view of the rear suspension device 1 of Figure 1 as seen from the rear of the vehicle. Although tires and wheels are not shown in Figures 1 and 2A to 2C, these tires and wheels are rotatably mounted on knuckles 31, which will be described later, and in the case of a rear-wheel drive vehicle, are connected to a drive shaft (not shown, only axle 32 is shown).

[0011] The rear suspension device 1 of this embodiment is suspended between the vehicle body 2 and the wheels 3 and includes two upper links and three lower links. Of the two upper links, the one located at the front of the vehicle is referred to as a first upper link 11, and the one located at the rear of the vehicle is referred to as a second upper link 12. Of the three lower links, the one located at the front most in the fore-and-aft direction of the vehicle is referred to as a first lower link 13, the one located in the middle in the fore-and-aft direction of the vehicle is referred to as a second lower link 14, and the one located at the rear most in the fore-and-aft direction of the vehicle is referred to as a third lower link 15. The lower links of the present invention are not limited to three lower links, and may be configured with two lower links or four or more lower links.

[0012] Although not particularly limited, the first upper link 11, the second upper link 12, the first lower link 13, the second lower link 14, and the third lower link 15 are rigid bodies formed from processed steel plates, cast products, forged products, etc. Rubber bushings (not shown in detail) are interposed at both ends of the first upper link 11, the second upper link 12, the first lower link 13, the second lower link 14, and the third lower link 15, with one end swingably attached to a bracket provided on the vehicle body 2 and the other end swingably attached to the knuckle 31 of the wheel 3.

[0013] Examples of the vehicle body 2 to which one ends of the first upper link 11, second upper link 12, first lower link 13, second lower link 14, and third lower link 15 are attached include a rear side member and a rear suspension member 21 fixed to the rear floor via a rubber bushing 211. In the illustrated embodiment, one ends of the first upper link 11, second upper link 12, first lower link 13, second lower link 14, and third lower link 15 are swingably attached to the rear suspension member 21, but some or all of them may also be swingably attached to the rear side member or the like.

[0014] The rear suspension device 1 of this embodiment includes, in order from the front of the vehicle, a first lower link 13, a second lower link 14, and a third lower link 15. Of these, the wheel 3 side ends of the first lower link 13 and the second lower link 14 are swingably attached to the lower part of the knuckle 31 via rubber bushings, and the vehicle body 2 side ends are swingably attached to the lower part of the rear suspension member 21 via rubber bushings. In contrast, the wheel 3 side end of the third lower link 15 is swingably attached to the center of the knuckle 31 via a rubber bushing, as shown in Figure 2C, and the vehicle body 2 side end is swingably attached to the center of the rear suspension member 21 via a rubber bushing.

[0015] The rear suspension device 1 of this embodiment further includes a shock absorber 16 and a spring 17. The lower end of the shock absorber 16 of this embodiment is swingably attached to the first lower link 13 as shown in Figures 1 and 2B, and the upper end is attached to the vehicle body 2 (not shown). The lower end of the spring 17 of this embodiment is attached to the second lower link 14 as shown in Figures 2A and 2C, and the upper end is attached to the vehicle body 2 (not shown).

[0016] The rear suspension device 1 of this embodiment includes an I-type upper link that includes a first upper link 11 and a second upper link 12. The ends of the first upper link 11 and the second upper link 12 that face the wheel 3 are swingably attached to the top of the knuckle 31 via rubber bushings, and the ends that face the vehicle body 2 are swingably attached to the bottom of the rear suspension member 21 via rubber bushings.

[0017] Figure 3A is a plan view schematically showing the first upper link 11 and the second upper link 12 of the rear suspension device 1 of this embodiment, and Figure 3B is a plan view schematically showing the first lower link 13, the second lower link 14, and the third lower link 15 of the rear suspension device 1 of this embodiment. In the rear suspension device 1 of this embodiment, the hardness of the rubber bushings, for example, is set so that the rigidity of the first upper link 11 and the rigidity of the second upper link 12 are different values. By making the rigidity of the first upper link 11 and the second upper link 12 different, it is possible to set the rigidity in the vehicle width direction high while setting the rigidity in the vehicle fore-and-aft direction low.

[0018] In other words, the hardness of the rubber bushings is set so that the rigidity of one upper link is higher or lower than that of the other upper link. Increasing the hardness of the rubber bushings increases the rigidity of the rubber bushings, thereby increasing the rigidity of the upper link. Conversely, decreasing the hardness of the rubber bushings decreases the rigidity of the rubber bushings, thereby decreasing the rigidity of the upper link. Note that the means for making the rigidity of one upper link different from that of the other upper link is not limited to setting the rigidity of the rubber bushings; the rigidity of the upper link body may also be made different by changing the shape or material of the upper link. Note that the rigidity of the upper link refers to the degree to which it is difficult to deform in response to a force input to the upper link; if the deformation in response to the input is small, the rigidity is said to be high, and if the deformation is large, the rigidity is said to be low.

[0019] In particular, in the rear suspension device 1 of this embodiment, the rigidity of the first upper link 11 and the second upper link 12 is made different from each other by setting the rigidity of the upper link having a relatively large inclination angle θ with respect to the vehicle width direction in a plan view of the vehicle to be lower than the rigidity of the upper link having a relatively small inclination angle θ with respect to the vehicle width direction. In other words, as shown in the plan view of Fig. 3A, if the angle between the wheel axle 32 parallel to the vehicle width direction and the extension direction of the first upper link 11 is inclination angle θ1, and the angle between the wheel axle 32 parallel to the vehicle width direction and the extension direction of the second upper link 12 is inclination angle θ2, then in the rear suspension device 1 of the illustrated embodiment, θ1 < θ2. Therefore, in order to make the rigidity of the second upper link 12 lower than that of the first upper link 11, the rigidity of the rubber bushing of the second upper link 12 is made low and the rigidity of the rubber bushing of the first upper link 11 is made high.

[0020] By relatively reducing the rigidity of the second upper link 12, which has a large inclination angle θ2 with respect to the vehicle width direction, the rigidity in the vehicle width direction can be relatively increased, thereby improving turning response. Also, by relatively increasing the rigidity of the first upper link 11, which has a small inclination angle θ1 with respect to the vehicle width direction, the rigidity in the front-rear direction of the vehicle can be relatively reduced, thereby reducing impact when going over a bump.

[0021] Note that when the inclination angle θ1 of the first upper link 11 and the inclination angle θ2 of the second upper link 12 are equivalent in a plan view of the vehicle (for example, the absolute value of the difference between θ1 and θ2 is 5° or less), the rigidity may be varied depending on the distance L between the first upper link 11 and the second upper link 12 and the wheel axle 32. FIG. 3C is a plan view schematically showing an upper link according to another example of the rear suspension device 1 of this embodiment. In this figure, the absolute value of the difference between the inclination angle θ1 of the first upper link 11 and the inclination angle θ2 of the second upper link 12 is 5° or less, which means that they are equivalent. In this case, the distance L1 between the wheel axle 32 and the first upper link 11 is compared with the distance L2 between the wheel axle 32 and the second upper link 12, and the rigidity of the upper link that is relatively far from the wheel axle 32 is set lower than the rigidity of the upper link that is relatively far from the wheel axle 32. In the example shown in the figure, since L1<L2, the rigidity of the rubber bushing of the second upper link 12 may be reduced and the rigidity of the rubber bushing of the first upper link 11 may be increased so that the rigidity of the second upper link 12 is lower than the rigidity of the first upper link 11. Note that the distance L between the upper link and the wheel axle 32 may be compared as a distance on the same straight line in the fore-and-aft direction of the vehicle, or as a shortest distance.

[0022] By relatively reducing the rigidity of the second upper link 12, which is located at a greater distance from the wheel axle 32, the rigidity in the vehicle width direction can be relatively increased, thereby improving turning response. Also, by relatively increasing the rigidity of the first upper link 11, which is located at a shorter distance from the wheel axle 32, the rigidity in the vehicle's front-rear direction can be relatively reduced, thereby reducing the impact when going over a bump.

[0023] Furthermore, in the rear suspension device 1 of this embodiment, as shown in FIG. 2B , the attachment position P1, in a side view (or a front view or a rear view) of the vehicle, of the first upper link 11, which has a relatively high rigidity, on the wheel 3 side is set higher than the attachment position P2, in a side view (or a front view or a rear view) of the second upper link 12, which has a relatively low rigidity, on the wheel 3 side. FIG. 3D is a rear view of FIG. 3A , which schematically illustrates the relationship between the attachment positions P1, P2 of the first upper link 11 and the second upper link 12 on the wheel 3 side for easy understanding. As shown in the figure, when a force F in the direction of the arrow acts on the lower part of the wheel 3, a force is generated that tilts the upper part of the wheel 3 outward. In this case, it is preferable that the attachment position of the upper link on the wheel 3 side is higher. However, in the rear suspension device 1 of this embodiment, this role is played by the first upper link 11, which has a relatively high rigidity, so that camber rigidity, i.e., high lateral rigidity, can be efficiently ensured.

[0024] That is, there is a certain upper limit to the height of the attachment position of the upper link on the wheel 3 side in the layout of the rear suspension unit 1. In the rear suspension unit 1 of this embodiment, the attachment position P1 on the wheel 3 side of the first upper link 11, which has a relatively high rigidity, is set at a position higher than the attachment position P2 on the wheel 3 side of the second upper link 12, which has a relatively low rigidity, and therefore higher lateral rigidity can be ensured compared to the reverse case, i.e., the case where the attachment position P2 on the wheel 3 side of the second upper link 12, which has a relatively low rigidity, is set at a position higher than the attachment position P1 on the wheel 3 side of the first upper link 11, which has a relatively high rigidity.

[0025] Furthermore, in the rear suspension device 1 of this embodiment, as shown in the plan view of FIG. 3A, in plan view of the vehicle, the following are arranged in order from the front in the longitudinal direction of the vehicle: shock absorber 16 installed between vehicle body 2 and first lower link 13; first upper link 11 having a relatively high rigidity; wheel axle 32 (drive shaft in the case of a rear-wheel drive vehicle); spring 17 installed between vehicle body 2 and second lower link 14; and second upper link 12 having a relatively low rigidity.

[0026] Generally, the center of rotation of the rear suspension unit 1 is set forward of the wheel 3 to suppress changes in posture during braking. As in the rear suspension unit 1 of this embodiment, by supporting the shock absorber 16 on the first lower link 13, which is located at the frontmost position of the vehicle, it is possible to reduce the stroke of the shock absorber 16 relative to the stroke of the wheel 3. As a result, the height of the upper end of the shock absorber 16 can be set low, which allows for a larger volume of luggage space behind the cabin, making it suitable for use in a station wagon or the like.

[0027] Furthermore, by supporting spring 17 on second lower link 14, which is located rearward of wheel axle 32, it is possible to ensure the stroke amount of spring 17. By locating spring 17 rearward of wheel axle 32, second upper link 12, which has a large inclination angle θ2 and a relatively low rigidity, can be located rearward of spring 17, while first upper link 11, which has a small inclination angle θ1 and a relatively high rigidity, can be located in front of wheel axle 32.

[0028] Second Embodiment Fig. 4 is a perspective view showing a rear suspension device 1 according to a second embodiment of the present invention, Fig. 5A is a plan view of the rear suspension device 1 of Fig. 4 as seen from above the vehicle, Fig. 5B is a side view of the rear suspension device 1 of Fig. 4 as seen from the side of the vehicle, and Fig. 5C is a rear view of the rear suspension device 1 of Fig. 4 as seen from the rear of the vehicle.

[0029] The rear suspension device 1 of this embodiment is suspended between a vehicle body 2 and wheels 3 and includes two upper links and three lower links. Of the two upper links, the one located at the front of the vehicle is referred to as a first upper link 11, and the one located at the rear of the vehicle is referred to as a second upper link 12. Of the three lower links, the one located at the front most in the longitudinal direction of the vehicle is referred to as a first lower link 13, the one located in the middle in the longitudinal direction of the vehicle is referred to as a second lower link 14, and the one located at the rear most in the longitudinal direction of the vehicle is referred to as a third lower link 15. Of the first lower link 13, the second lower link 14, and the third lower link 15, the ends of the first lower link 13 and the second lower link 14 located on the wheel 3 side are swingably attached to the lower part of the knuckle 31 via rubber bushings, and the ends located on the vehicle body 2 side are swingably attached to the lower part of the rear suspension member 21 via rubber bushings. In contrast, as shown in FIG. 5C, the end of the third lower link 15 on the wheel 3 side is swingably attached to the center of the knuckle 31 via a rubber bushing, and the end on the vehicle body 2 side is swingably attached to the center of the rear suspension member 21 via a rubber bushing.

[0030] The rear suspension device 1 of this embodiment further includes a shock absorber 16 and a spring 17. The rear suspension device 1 of this embodiment differs from the rear suspension device 1 of the first embodiment in the mounting position of the shock absorber 16. That is, the lower end of the shock absorber 16 of this embodiment is swingably mounted to the top of the knuckle 31 as shown in Figures 4, 5B, and 5C, and the upper end is mounted to the vehicle body 2 (not shown). Note that the lower end of the spring 17 of this embodiment is mounted to the second lower link 14 as shown in Figures 5A and 5C, and the upper end is mounted to the vehicle body 2 (not shown).

[0031] The rear suspension device 1 of this embodiment differs from the rear suspension device 1 of the first embodiment described above in the mounting position of the shock absorber 16, but has the same configuration as the rear suspension device 1 of the first embodiment described above, including the configurations of the first upper link 11 and the second upper link 12. For this reason, the same reference numerals as those used in Figures 1 to 2C are used in Figures 4 to 5C, and the explanation given in the first embodiment with reference to Figures 1 to 2C is incorporated herein by reference.

[0032] Figure 6A is a plan view schematically showing the first upper link 11 and the second upper link 12 of the rear suspension device 1 of this embodiment, and Figure 6B is a plan view schematically showing the first lower link 13, the second lower link 14, and the third lower link 15 of the rear suspension device 1 of this embodiment.

[0033] In the rear suspension device 1 of this embodiment, as shown in the plan view of Figure 6A, in a plan view of the vehicle, the following components are arranged in order from the front in the longitudinal direction of the vehicle: a first upper link 11 with a relatively high rigidity; a shock absorber 16 installed between the wheel axle 32 (or the drive shaft in the case of a rear-wheel drive vehicle) and the vehicle body 2 and the knuckle 31; a spring 17 installed between the vehicle body 2 and the second lower link 14; and a second upper link 12 with a relatively low rigidity.

[0034] By positioning the shock absorber 16 above the wheel axle 32 (or the drive shaft in the case of a rear-wheel drive vehicle) as in the rear suspension unit 1 of this embodiment, the offset between the shock absorber 16 and the wheel axle 32 is reduced, and it is possible to prevent a decrease in the cushioning effect of the shock absorber 16 due to deflection when the rear suspension unit 1 strokes. Furthermore, if the upper end of the shock absorber 16 is positioned higher on the vehicle body 2, the stroke amount of the shock absorber 16 increases. As a result, ride comfort can be improved, making it suitable for use in vehicles such as sedans.

[0035] <<Third Embodiment>> Figure 7 is a perspective view showing a rear suspension device 1 according to a third embodiment of the present invention, Figure 8A is a plan view of the rear suspension device 1 of Figure 7 as seen from above the vehicle, Figure 8B is a side view of the rear suspension device 1 of Figure 7 as seen from the side of the vehicle, and Figure 8C is a rear view of the rear suspension device 1 of Figure 7 as seen from the rear of the vehicle.

[0036] The rear suspension device 1 of this embodiment is suspended between a vehicle body 2 and wheels 3 and includes two upper links and three lower links. Of the two upper links, the one located at the front of the vehicle is referred to as a first upper link 11, and the one located at the rear of the vehicle is referred to as a second upper link 12. Of the three lower links, the one located at the front most in the longitudinal direction of the vehicle is referred to as a first lower link 13, the one located in the middle in the longitudinal direction of the vehicle is referred to as a second lower link 14, and the one located at the rear most in the longitudinal direction of the vehicle is referred to as a third lower link 15. Of the first lower link 13, the second lower link 14, and the third lower link 15, the ends of the first lower link 13 and the second lower link 14 located on the wheel 3 side are swingably attached to the lower part of the knuckle 31 via rubber bushings, and the ends located on the vehicle body 2 side are swingably attached to the lower part of the rear suspension member 21 via rubber bushings. In contrast, the end of the third lower link 15 on the wheel 3 side is swingably attached to the center of the knuckle 31 via a rubber bushing, as shown in FIG. 8C, and the end on the vehicle body 2 side is swingably attached to the center of the rear suspension member 21 via a rubber bushing.

[0037] The rear suspension device 1 of this embodiment further includes a shock absorber 16 and a spring 17. The rear suspension device 1 of this embodiment differs from the rear suspension device 1 of the first embodiment in the mounting position of the shock absorber 16. That is, the lower end of the shock absorber 16 of this embodiment is mounted to the second lower link 14 as shown in Figures 7, 8A, and 8C, and the upper end is mounted to the vehicle body 2 (not shown). Note that the lower end of the spring 17 of this embodiment is mounted to the second lower link 14 as shown in Figures 8A and 8C, and the upper end is mounted to the vehicle body 2 (not shown).

[0038] The rear suspension device 1 of this embodiment differs from the rear suspension device 1 of the first embodiment described above in the mounting position of the shock absorber 16, but has the same configuration as the rear suspension device 1 of the first embodiment described above, including the configurations of the first upper link 11 and the second upper link 12. For this reason, the same reference numerals as those used in Figures 1 to 2C are used in Figures 7 to 8C, and the explanation given in the first embodiment with reference to Figures 1 to 2C is incorporated herein by reference.

[0039] Figure 9A is a plan view schematically showing the first upper link 11 and the second upper link 12 of the rear suspension device 1 of this embodiment, and Figure 9B is a plan view schematically showing the first lower link 13, the second lower link 14, and the third lower link 15 of the rear suspension device 1 of this embodiment.

[0040] In the rear suspension device 1 of this embodiment, as shown in the plan view of Figure 9A, in a plan view of the vehicle, the following are arranged, in order from the front in the longitudinal direction of the vehicle: a first upper link 11 with a relatively high rigidity, a wheel axle 32 (a drive shaft in the case of a rear-wheel drive vehicle), a shock absorber 16 installed between the vehicle body 2 and the second lower link 14, a spring 17 installed between the vehicle body 2 and the second lower link 14, and a second upper link 12 with a relatively low rigidity.

[0041] As in the rear suspension device 1 of this embodiment, by supporting the spring 17 by the second lower link 14 located rearward of the wheel axle 32, it is possible to ensure the stroke amount of the spring 17. Furthermore, by locating the spring 17 rearward of the wheel axle 32, the second upper link 12, which has a large inclination angle θ2 and a relatively low rigidity, can be located rearward of the spring 17, while the first upper link 11, which has a small inclination angle θ1 and a relatively high rigidity, can be located in front of the wheel axle 32.

[0042] Furthermore, by supporting the shock absorber 16 on the second lower link 14 located behind the wheel axle 32, the stroke of the shock absorber 16 relative to the stroke of the wheel 3 can be increased, thereby improving ride comfort. Also, by setting the height of the upper end of the shock absorber 16 low, the volume of the luggage compartment behind the cabin can be increased, making it suitable for use in a station wagon or the like.

[0043] DESCRIPTION OF SYMBOLS 1...Rear suspension device 11...First upper link 12...Second upper link 13...First lower link 14...Second lower link 15...Third lower link 16...Shock absorber 17...Spring 2...Vehicle body 21...Rear suspension member 3...Wheel 31...Knuckle 32...Wheel axle

Claims

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5. In a rear suspension device that connects the wheels and the vehicle body with two upper links and three lower links, The rigidity of the two upper links is different, In a plan view of the vehicle, the rear suspension device is arranged in the following order from the front of the vehicle in the longitudinal direction: a shock absorber installed between the vehicle body and one of the three lower links that is frontmost in the longitudinal direction of the vehicle; an upper link having a relatively high rigidity; a wheel axle; a spring installed between the vehicle body and one of the three lower links that is a center lower link in the longitudinal direction of the vehicle; and an upper link having a relatively low rigidity.

6. In a rear suspension device that connects the wheels and the vehicle body with two upper links and three lower links, The rigidity of the two upper links is different, In a plan view of the vehicle, a rear suspension device is arranged in the following order from the front in the longitudinal direction of the vehicle: an upper link with a relatively high rigidity; a shock absorber installed between the wheel axle and the vehicle body and the knuckle; a spring installed between the vehicle body and the central lower link in the longitudinal direction of the vehicle out of the three lower links; and an upper link with a relatively low rigidity.

7. In a rear suspension device that connects the wheels and the vehicle body with two upper links and three lower links, The rigidity of the two upper links is different, In a plan view of the vehicle, the rear suspension device has, arranged in order from the front in the fore-and-aft direction of the vehicle, an upper link with a relatively high rigidity, a wheel axle, a shock absorber installed between the vehicle body and the frontmost lower link in the fore-and-aft direction of the vehicle of the three lower links, a spring installed between the vehicle body and the central lower link in the fore-and-aft direction of the vehicle of the three lower links, and an upper link with a relatively low rigidity.

8. 8. The rear suspension device according to claim 5, wherein the rigidity of the upper link is set by the rigidity of a rubber bushing attached to an end of the upper link.

9. 9. The rear suspension device according to claim 5, wherein the rigidity of the upper link having a relatively large inclination angle with respect to the vehicle width direction in a plan view of the vehicle, out of the two upper links, is lower than the rigidity of the upper link having a relatively small inclination angle with respect to the vehicle width direction in a plan view of the vehicle.

10. 9. The rear suspension device according to claim 5, wherein, when the two upper links have the same inclination angle with respect to the vehicle width direction, the upper link that is relatively far from the wheel axle in a plan view of the vehicle has lower rigidity than the upper link that is relatively far from the wheel axle in a plan view of the vehicle.

11. 11. The rear suspension device according to claim 5, wherein an attachment position of the wheel side of the upper link having a relatively high rigidity, as viewed from the side, front, or rear of the vehicle, is higher than an attachment position of the wheel side of the upper link having a relatively low rigidity, as viewed from the side, front, or rear of the vehicle.