JP2524986B2 - Vehicle suspension - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension system, and more particularly to a vehicle suspension system having no steering function.

2. Description of the Related Art Generally, in a vehicle such as an automobile, steering is performed by front wheels, and rear wheels are simply supported by a vehicle body side and followed by front wheels. Therefore, this rear wheel side suspension device, in particular, an independent suspension type, has a wheel support for rotatably supporting a wheel as shown in, for example, Japanese Utility Model Laid-Open No. 60-116513.
It is attached to the vehicle body side by a left-right direction positioning member arranged in the vehicle left-right direction, a front-back direction positioning member arranged in the vehicle front-rear direction, and the like. An elastic member such as a rubber bush is provided on each of the left-right direction positioning member and the front-rear direction positioning member so that road surface vibration input from the wheels to the vehicle body is absorbed.

The left-right direction positioning member is composed of a pair of front and rear links that are arranged so as to face each other in the vehicle front-rear direction, and these front and rear links are arranged so as to sandwich the wheel center in plan view (the vehicle vertical direction), and Arrange the intersection of the axis of the front-rear direction positioning member and the center line of the wheel width direction (wheel left-right direction) so that the space between the front and rear links is internally divided into L ₁ : L ₂ from the front link side. When the combined spring constants of the rubber bushes related to the link and the rear link are represented by K _f and Kr, L ₁ / L ₂ =
The selection is made so that the relationship Kr / K _f is established so that the toe change that affects the longitudinal load acting on the wheels is prevented.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in such a conventional vehicle suspension system, since the front link is arranged in front of the vehicle with respect to the wheel center, the axis of the front-rear direction positioning member is the center line in the width direction of the wheel. In order to arrange the point intersecting with the front and rear links so as to be internally divided, the mounting angle of the front-rear direction positioning member with respect to the vehicle front-rear direction inevitably becomes large in the vehicle vertical direction. Therefore, in an FF vehicle or the like in which the gasoline tank is arranged below the rear seat, the mounting point of the front-rear direction positioning member on the vehicle body side largely enters the inside of the vehicle. The occupied space becomes narrow, and it becomes extremely difficult to increase the tank capacity.

Further, since the input to the front-rear direction positioning member increases as the mounting angle increases, the weight of the front-rear rear positioning member and its mounting member increases from the viewpoint of ensuring strength, and cost up is inevitable. Will end up.

By the way, if the mounting angle of the front-rear direction positioning member is simply reduced, the point where the axis line of the front-rear direction positioning member and the center line in the width direction of the wheel intersect is arranged further rearward of the vehicle than the rear link. Moreover, when a load from the front to the rear of the vehicle is applied, the wheels are toeed out, which causes various problems that the running stability is deteriorated.

Therefore, the present invention, while satisfying the suspension characteristics,
An object of the present invention is to provide a vehicle suspension system in which the mounting angle of the front-rear direction positioning member can be reduced.

Means for Solving the Problems In order to achieve the above object, the present invention provides a wheel support that rotatably supports a wheel, and the wheel support is connected to a vehicle body in the vehicle left-right direction via an elastic member, A vehicle suspension device comprising: a left-right direction positioning member composed of a pair of front and rear links arranged to face each other in the vehicle front-rear direction; and a front-rear direction positioning member connecting the wheel support to a vehicle body in the vehicle front-rear direction. The front link of the pair of left and right positioning members is arranged on the wheel center line or behind the wheel center line in the vehicle vertical direction, and the wheel support is above the vehicle in the vehicle front and rear direction. A point g at which the axis of the front-rear direction positioning member intersects a straight line 1 connecting a point rotatably supported to the side and a point of application of a front-rear force input to the wheel, and passing through the intersection g to indicate the vehicle front-rear direction. A vertical plane to the ground P and a point Q at which the axis of the front-back direction positioning member intersects with the vertical plane P to the ground are determined, and this crossing point Q is the distance between the pair of left-right direction positioning members in the vehicle vertical direction. link side of m: If placed in a position which internally divides n, and the previous left right direction positioning member, and a combined spring constant in the axial direction of the elastic member being respectively provided in the rear link K _f, and Kr, m / n ≦ Kr
It is configured by setting to be / K _f .

With the above-described configuration, in the vehicle suspension device of the present invention, the front link is arranged on the wheel center line or on the vehicle rear side of the vehicle center line, so that the left-right direction positioning member is arranged in the vehicle direction as a whole. . Therefore, when the intersection Q of the axis line of the front-rear direction positioning member is arranged between the front and rear links of the left-right direction positioning member, the mounting angle of the front-rear direction positioning member can be reduced. Even if the front links are arranged on or behind the wheel center line in this manner, the ratio m: n at which the intersection Q internally divides between the front and rear links and the combined spring constants K _f , Kr of each link. since the relationship between the set to _{m / n ≦ Kr / K f} , even when the longitudinal force on the wheel is inputted, it is possible wheels to prevent the the toe-out.

Example Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

1 (A) and 1 (B) show a vehicle suspension system 1 showing a first embodiment of the present invention, and a suspension type suspension system will be described as an example. That is, in this suspension device 1, a lower end of a strut 4 arranged in the vehicle vertical direction is integrally fixed to a spindle 3 as a wheel support member that rotatably supports a wheel 2, and the upper end of the strut 4 is fixed. Is attached to the vehicle body (not shown) via the insulator 5. The insulator 5 serves as an intersection of the rotation center axis of the spindle 3 as a wheel support and the vehicle body. The strut 4 is provided with an outer cylinder 4a fixedly mounted on the spindle 3 and a shock absorber (not shown) housed in the outer cylinder 4a, and a piston rod 4b of the shock absorber.
Is projected from the upper end of the outer cylinder 4a so as to be retractable.

Further, the spindle 3 includes a pair of front and rear front and rear links 7, which serve as a lateral direction positioning member arranged inside the vehicle.
8 and a radius rod 9 as a front-rear direction positioning member arranged in front of the vehicle, which is mounted on the vehicle body side. The front and rear links 7 and 8 are provided with rubber bushes 10,10a, 11,11a, 12,12a schematically indicated by white circles in the figure, and the front and rear links 7 and 8 are connected to the spindles through the rubber bushes. 3 and body frame cross member 1
The radius rod 9 is mounted between the spindle 3 and the side member 14 of the vehicle body frame. Therefore, the front and rear links 7 and 8 can swing up and down and front and rear of the vehicle with respect to the vehicle body by deformation of the rubber bush shims 10a and 11b, and the radius slot 9 can move up and down and left and right of the vehicle by the rubber bush 12a. It is possible to swing.

By the way, the front and rear links 7, 8 are arranged substantially parallel to each other and substantially parallel to the road surface X, and the front link 7 is further arranged at the wheel center in a vehicle vertical direction view (FIG. 1A). It is arranged behind the line C in the vehicle. Further, the radius slot 9 is disposed substantially parallel to the road surface X, and as shown in FIG. 1A, the vehicle body side supporting point, that is, the front rubber bush 12a is moved from the spindle side supporting point, that is, the rear rubber bush 12 to the vehicle. It is arranged inward and is inclined with a horizontal inclination angle θ with respect to the vehicle front-rear direction.

2 (A), (B), and (C) are schematic views of the suspension device 1 shown in FIG. 1 as viewed in a vehicle vertical direction, a vehicle longitudinal direction, and a vehicle lateral direction, respectively. The same components as those are denoted by the same reference numerals.

Here, in this embodiment, as shown in FIG.
When viewed from the vehicle front-rear direction, the spindle 3 is rotatably supported above the vehicle toward the vehicle body (not shown), that is, the insulator 5 above the strut 4 and the wheels 2 are input from the vehicle front toward the vehicle rear. The point of action of the longitudinal force, for example, the ground point e of the wheel 2 on which the longitudinal force F _G due to the frictional force with the road surface X during braking acts is connected by a line segment l, and the axis line of the radius rod 9 intersects this line segment l. A point g is obtained, and a ground vertical plane P perpendicular to the road surface X is obtained by passing through the intersection g and pointing in the vehicle front-rear direction. Next, the point Q at which the axis of the radius slot 9 intersects with the ground vertical plane P in the vertical direction of the vehicle of FIG. Then, in this embodiment, the intersection Q is arranged between the front link 7 and the rear link 8, and between the front and rear links 7 and 8 on the ground vertical plane P from the front link 7 by m: The inclination angle θ of the radius rod 9 is determined so as to be internally divided into n, and
The insulator 5 at the upper end of the strut 4 is arranged inside the vehicle from the center of the wheel 2.

That is, in the present embodiment, the radius rod 9 is tilted at the horizontal tilt angle θ so that the wheel 2 is contacted during braking as shown in FIGS. 2 (A) and 2 (B). When the longitudinal force F _G acts on the point e, the component force frx on the inside of the vehicle acts on the radius rod 9, and the wheel determined by the load ratio acting on the front and rear links 7, 8 by this component force frx. The moment in the toe change direction of 2 is affected. Therefore, in this embodiment, the horizontal tilt angle θ of the radius rod 9 is set to the component force frx, which acts on the front and rear links 7, 8 when the front-rear load F _G acts on the wheel 2. The ratio of fry and the axial synthetic spring constants of the rubber bushes 10,10a and 11,11a provided on the front and rear links 7 and 8, respectively (the synthetic spring constant of the front link 7 is K _f , the synthetic spring of the rear link 8 is By setting the constant to be Kr.), The compliance steer change of the wheel 2 is prevented or the toe-in direction is directed.

Next, the loads fp _f , f acting on the front and rear links 7,8
Find pr.

That is, in FIG. 2, l is the front-rear direction span between the radial slot 9 and the spindle side rubber bushes 12, 11 of the rear link 8, and l ₁ is the front-back direction between the radial slot 9 and the spindle side rubber bushes 12, ₁₀ of the front link 7. Span, l ₂ is forward,
The front-rear span between the spindle side rubber bushes 10 and 11 of the rear links 7 and 8, lp _f and lpr are the front-rear span between the front and rear links 7 and 8 of the spindle side rubber bushings 10 and 11 with respect to the insulator 5. , S ₁ is the horizontal span between the spindle side rubber bush 12 of the radius slot 9 and the insulator 5 of the strut 4, and S ₂
Is a left-right span between the insulator 5 and the ground contact point e of the wheel 2, and S ₃ is a left-right span between the insulator 5 and the ground vertical plane P. Further, H is a vertical span between the insulator 5 and the road surface X, hs, hr is a vertical span between the insulator 5 and the road surface X relative to the spindle side rubber bush 12 of the radius slot 9, hw, hp
Is the insulator 5 and wheel 2 center and front and rear links
The vertical span between the rubber bushings 10, 11 of 7, 8 and f
r, fp _f, fpr, fs, when fs _X is exerted is longitudinal force F _G, Rajiasurotsudo 9, the forward link 7, the rear link 8 respectively show a load acting on Sutoratsuto 4. The load of the radius slot 9 fr
Is the component force fr inward, forward and upward due to the inclination angle θ.
_X , fry is occurring.

Under these conditions, the balance of moments around the insulator 5 at the upper end of the strut 4 in FIG. 2 (C) (clockwise is positive) fry · hs−F _G · H = 0 Is derived.

Next, in FIG. 2 (B), from the triangle formed by the road surface X, the line segment 1 and the perpendicular to the road surface X of the insulator 5. Is introduced, Is obtained.

Furthermore, the Hitoshiri fit equation of the Inshiyureta 5 around the moment in FIG. 2 (A) (a clockwise positive) Request, frx · lr + fry · S 1 -fp f · lp f -fpr · lpr-F G · S ₂ = 0 ...
… Is obtained, and from the balance in the vehicle left-right direction (vertical direction in the figure), fp _f = frx + fpr …… is obtained. Furthermore, from the horizontal inclination of the radius slot 9, frx ＝ fry ・ tan θ …… is obtained. can get.

First, the axial force fp _f of the front link 7 is calculated based on the above equations.

In Formula, Formula and lr + lpr = l, and rearranging by replacing the condition of _{lp f + lpr = l 2,} (l · tanθ + S 1) · fry-l 2 · fp f -F G · S 2 = 0 , and the Is guided.

By substituting formulas and formulas into this and rearranging, Is obtained.

 Next, the axial force fpr of the rear link 8 is calculated.

By substituting the equation, the equation, and the conditions of lr-lpf = l ₁ and lpr + lpf = l ₂ into the equation, and rearranging, (l ₁ · tan θ + S ₁ ) · fry−fpr · l ₂ −F _G · S ₂ = 0 , Is guided.

Then, by substituting the formulas and formulas into this formula and rearranging, Is obtained.

By the way, in the suspension system 1 shown in FIG. 2, the longitudinal force acts on the ground contact point e of the wheel 2 during braking or the like, and the insulator 5 at the upper end of the strut 4 has a vertical wheel width. The case where the insulator 5 is arranged on the inner side of the vehicle with respect to the directional center line is shown in FIG. 3 (B), and the insulator 5 is arranged on the wheel width direction center line as shown in FIG. 3 (A). It may be arranged outside the vehicle with respect to the center line in the wheel width direction as shown. in this case,
In the case where the insulator 5 is arranged on the center line in the wheel width direction, when a balance equation of the moment around the insulator 5 (clockwise is positive) is calculated, frx · lr−fry · S ₁ − fp _f · lp _f −fpr · lpr = 0 ...

Therefore, as a result, the axial force fp _f of the front link 7 is And the axial force fpr of the rear link 8 is Becomes

Similarly, in the case where the insulator 5 is arranged outside the vehicle from the center line in the wheel width direction, when the balance equation of the moment around the insulator 5 (clockwise is positive) is found, frx ・ lr ＋ F _G・ S ₂ − fp _f · lp _f −fpr · lpr−fry · S ₁ = 0 ...
... is obtained, and therefore the axial force fp _f of the front link 7 is And the axial force fpr of the rear link 8 is Becomes

Next, in this way, the axial forces fp _f , fpr of the front and rear links 7, 8 obtained according to the change in the arrangement of the insulator 5 are positive,
Judge negative. By the way, in the axial force fp _f equation of the front link 7 shown in the above equations, equations, l · tan θ is shown in FIG. 2 (A).
As shown in, the distance from the rubber bush 12 on the spindle 3 side of the radius slot 9 to the intersection Q ₁ of the vehicle between the axis of the rear link 8 and the axis of the radius slot 9 in the vehicle left-right direction. Axial force of link 8
In the fpr equation, l ₁ tan θ is the distance in the vehicle left-right direction from the rubber bush 12 to the intersection Q ₂ between the axis of the front link 7 and the axis of the radius slot 9. Further, in the above formulas, S ₁
Is the distance between the rubber bush 12 and the insulator 5 at the upper end of the strut 4 in the vehicle left-right direction, and S ₃ is the distance between the insulator 5 and the above-mentioned vertical plane P to the ground, and these distances (l · tan θ, l ₁ · tan θ, S ₁ , S ₃ ) When the relations are judged by the above equations, fp _f > 0, fpr <0, and the front and rear links
A compressive load acts on both 7 and 8, but in this case, the combined spring constant K _f of the rubber bushes 10 and 10a of the front link 7 in the axial direction is reduced in consideration of the magnitudes of the front and rear compressive loads. By increasing the axial synthetic spring constant Kr of the rubber bushes 11, 11a of the rear link 8, the compliance steer can be prevented from toe-in or change. The relationship between the axial forces fp _f and fpr at this time and the composite spring constants K _f and Kr will be determined below.

First, the axial force fp _f of the front link 7 shown in FIG.
The axial force fpr of the rear link 8 is given by the equation. Therefore, when the ratio of these two axial forces is calculated, Becomes

This equation is derived from FIG. 2 above. (Note that this equation is shown in FIG. 3 (A).
Similarly, it can be obtained from the equation based on the above equation and from the equation based on FIG. 3 (B). ). That is, the axial force ratio is equal to the ratio of the distance at which the intersection Q internally divides between the front and rear links 7 and 8, and it can be considered that the load acts on this internally dividing point. Therefore, the condition for preventing the toe change of the wheel 2 with respect to the longitudinal force F _{G is} to make the overall deformation amounts of the rubber bushes 10, 10a and 11, 11a of the links 7, 8 equal to each other. This is achieved by adjusting the composite spring constants K _f and Kr of 7,8. That is, In addition, in order to make compliance steer toe-in from the viewpoint of running stability, Is sufficient.

That is, in the present embodiment, although the front link 7 is arranged rearward of the vehicle center line C, the combined spring constants K _f and Kr are set so as to satisfy the above equation, and the brake is thus set. When the longitudinal force F _G acts on the ground contact point e of the wheel 2 at the time of running, the toe change of the wheel 2 can be prevented or the running stability can be secured with a slight toe-in tendency. Further, by arranging the front link 7 rearward of the wheel center line C, the mounting angle θ of the radius rod 9 can be reduced, the axial load acting on the radius rod 9 can be reduced, and the vehicle body side rubber bush 12a can be further reduced. It can be located outside the vehicle. As a result, the space occupied by the fuel tank T can be expanded as shown by the chain double-dashed line in FIG. 1 (A), and the tank capacity can be increased.

Even when the front link 7 is arranged such that the axis of the front link 7 is on the wheel center line C, the same result as in the above-described embodiment can be obtained.

FIGS. 4A and 4B show a second embodiment of the present invention,
The present invention is applied to a wishbone type suspension device 1a, and the same components as those in the first embodiment will be designated by the same reference numerals, and a duplicate description will be omitted.

That is, in the second embodiment, the end of the upward extending portion 3a integrally and upwardly extended from the spindle 3 is attached to the vehicle body via the rubber bush 5a and the upper arm 20 at the intersection of the rotation center axis of the spindle 3 and the vehicle body. It is connected. Incidentally, the rubber bushes 21, 22 are also provided between the upper arm 20 and the vehicle body, but the rubber bushes 21, 22 are not always required as long as the road surface vibration can be blocked by the rubber bushes 5a.

By the way, even in the wishbone type suspension device 1a, the front and rear links 7 and 8 and the radius rod 9 are provided as in the strut type shown in the first embodiment. Connect the front link to the wheel center line C
It is arranged on the upper side or on the rear side of the vehicle from the wheel center line C (in the illustrated example, it is arranged on the wheel center line C) and the ground plane P
The point Q at which the axis of the radius rod 9 intersects is arranged so as to internally divide the front and rear links 7 and 8 into m: n. Further, the axial forces fp _f and fpr of the front and rear links 7 and 8 at this time are also inside the vehicle from the center line in the wheel width direction due to the positional relationship of the rubber bush 5a with respect to the center line in the wheel width direction. In this case, the above formula and formula will be the same,
If the rubber bush 5a is on the wheel width direction center line, it will be the same as the above formula and formula, and if the rubber bush 5a is on the vehicle outer side of the wheel width direction center line, it will be the same as the above formula and formula. The same function as in each of the above-described embodiments is performed by setting the composite spring constants K _f and Kr of the rubber bushes 10, 10a and 11, 11a of the front and rear links 7 and 8 so as to satisfy the above expression. You can

Next, the strut-type suspension device 1 described in the first embodiment and the wishbone-type suspension device 1a described in the second embodiment correspond to the wheel 2 when braking as a longitudinal force F _G. Although the load acting on the ground contact point e is described above, the longitudinal force F _G may act on the wheel center Co during engine braking or the like. In this way, the longitudinal force F _G during engine braking is
The axial force fp _f , fpr of the front and rear links 7,8 when acting on
The suspension type suspension device 1 shown in FIG. 5 is used as an example. That is, this figure shows the same vehicle vertical direction view as in FIG. 2 in (A), the vehicle longitudinal direction view in (B) diagram, and the vehicle lateral direction view in (C) diagram, respectively. (B) In the figure, the straight line 1 connecting the insulator 5 at the upper end of the strut 4 and the wheel center Co, which is the point of action of the longitudinal force F _G , is taken to be the point where the axis of the radius rod 9 intersects, and the ground passing through this intersection g. The point where the vertical plane P intersects the axis of the radius slot 9 in FIG.

Therefore, in this case, from the equation for balancing the moments around the insulator 5 in FIG. 5 (C) (clockwise is positive), Was obtained, and from FIG. 5 (B) Is obtained.

Further, in FIG. 5 (A), the equation for balancing the moments around the insulator 5 (clockwise is positive) is the same as the equation described above, and the balancing equation for the vehicle left-right direction is also the same as the above equation. Become. When the following equations are analyzed in the same manner as below, the above equations and fp _f and fpr of the same equations are derived.

By the way, FIG. 5 shows the case where the insulator 5 is arranged inside the vehicle with respect to the center line in the wheel width direction, and before the case where the insulator 5 is arranged on the center line in the wheel width direction or outside the vehicle with respect to the center line in the wheel width direction. ， Back link 7,8
When the axial forces fp _f and fpr of are similarly obtained, the above equation and the same result as the above equation are obtained.

Therefore, even when the longitudinal force F _G acts on the wheel center Co, the front link 7 is arranged on the wheel center line or on the vehicle rear side of the wheel center line, and the intersection Q is set to the front,
When arranged between the axes of the rear links 7 and 8, prevent the compliance steer change or toe-in by tuning the combined spring constants K _f and Kr of the rubber bushings 10, 10a and 11, 11a as described above. You can Needless to say, this also applies to the wishbone type suspension device 1a of the second embodiment when the longitudinal force F _G acts on the wheel center Co.

By the way, in each of the above-mentioned embodiments, the front and rear links, respectively.
Although 7 and 8 are shown arranged in parallel, the present invention is not limited to this, and they may be arranged in a trapezoidal shape in the vertical direction of the vehicle.

EFFECTS OF THE INVENTION As described above, the suspension system for a vehicle according to the present invention has the straight line (1), the intersection (g), the vertical plane to the ground (P), and the mounting angle between the vertical plane to the ground (P) and the longitudinal positioning member. The determined intersections (Q) are sequentially obtained, and the intersections (Q) are arranged between the front and rear links of the lateral positioning member so that the front links are arranged on the wheel center line or behind the wheel center line in the vehicle. Therefore, the intersection (Q) can be moved further rearward, and the mounting angle with the front-rear direction positioning member can be significantly reduced. Therefore, the mounting point of the front-rear direction positioning member on the vehicle body side can be arranged further outward of the vehicle, the exclusive space of the fuel tank can be expanded to increase the tank capacity, and the front-rear direction positioning member can be acted. The axial load can be reduced, the strength can be reduced accordingly, and the weight of the front-rear direction positioning member itself and the mounting member can be reduced, and the weight of the vehicle body and the cost can be reduced. Further, even though the mounting angle of the front-rear direction positioning member is reduced in this way and various effects are achieved, the combined spring constants K _f and Kr of the elastic members provided on the front and rear links are set to m / n ≦ Kr. Since it is set so that / K _f is satisfied, it is possible to prevent the change of compliance steer even if the longitudinal force acts on the wheel or to make it toe-in, and it is possible to achieve a great improvement in running stability. Have the effect.

[Brief description of drawings]

FIG. 1 shows a first embodiment of a vehicle suspension system according to the present invention,
FIG. 1A is a schematic plan view showing one side of the suspension system, FIG. 2B is a side view of the same, and FIG. 2 is generated by the longitudinal force acting on the wheel grounding point in the first embodiment. FIG. 3A shows a schematic plan view, FIG. 3B shows a schematic rear view, FIG. 3C shows a schematic side view, and FIG. 3A and FIG. FIG. 4 is another embodiment of the first embodiment of the invention, and is a schematic configuration diagram showing a vehicle up-down direction view and a vehicle front-rear direction view as one set, and FIG. 4 shows a second embodiment of the present invention. 1A is a schematic plan view corresponding to FIG. 1A, and FIG.
FIG. 5B is a schematic side view corresponding to FIG. 6B, and FIG. 5 is a schematic plan view showing the state of the acting force generated by the longitudinal force acting on the wheel center in the first embodiment. The figure (B) is a schematic rear view, and the figure (C) is a schematic side view. 1,1a ... Vehicle suspension system, 2 ... Wheels, 3 ... Spindle (wheel support), 4 ... Strut, 5 ... Insulator, 5a ... Rubber bush, 7 ... Front link (horizontal positioning member) ), 8 ... Rear link (horizontal positioning member), 9 ... Radius rod (front-back positioning member), 10, 10a, 11, 11a ... Rubber bush (elastic member).

Claims (1)

(57) [Claims] 1. A wheel support for rotatably supporting a wheel,
The wheel support is connected to the vehicle body in the vehicle left-right direction via an elastic member, and the wheel support is connected in the vehicle front-rear direction with a left-right direction positioning member composed of a pair of front and rear links arranged to face each other in the vehicle front-rear direction. In a vehicle suspension device including a front-rear direction positioning member that is connected to the vehicle body, a front link of the pair of left-right direction positioning members is located on a wheel center line or behind the wheel center line in the vehicle in a vertical direction of the vehicle. A straight line (1) connecting the point where the wheel support is rotatably supported on the vehicle body side above the vehicle and the point of action of the longitudinal force input to the wheel,
A point (g) where the axes of the longitudinal positioning members intersect,
A ground vertical plane (P) that passes through this crossover (g) and points in the vehicle front-rear direction, and a point (Q) at which the axis of the front-back direction positioning member intersects the ground vertical plane (P) are obtained, and this intersection ( Q) is arranged at a position where the distance between the pair of left and right positioning members is internally divided into m: n from the front link side in the vehicle vertical direction, and is provided on the front and rear links of the left and right positioning members, respectively. A suspension device for a vehicle, characterized in that m / n ≦ Kr / K _f is set so that the combined spring constants of the elastic members in the axial direction are K _f and Kr.