JPH06143952A - Rear suspension for vehicle - Google Patents

Abstract

PURPOSE:To improve lateral rigidity and the controllability of a vehicle compared with the conventional double wishbone type rear suspension having H- shaped arms. CONSTITUTION:This suspension has an upper arm 14 having the outer end pivotably connected to a carrier and the inner end pivotably supported by a car body 22 and a lower arm 16 having two outer ends pivotably attached to the carrier and the two inner ends spaced fore-and-aft from each other and pivotably supported by the car body. Also the suspension has an assist link 36 having the outer end pivotably attached to the carrier and the inner end pivotably supported by the car body. The assist link gives an energizing force along the axis between the carrier and car body, so that the play between the lower arm and carrier is absorbed constitutionally.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension of a vehicle such as an automobile, and more particularly to a rear suspension.

[0002]

2. Description of the Related Art As one of double-wishbone type rear suspensions for vehicles such as automobiles, for example, Japanese Unexamined Patent Publication (Kokai) No. Hei 2
As described in JP-A-136311, there is provided a carrier that rotatably supports a wheel, an upper arm and a lower arm, and at least one of the upper arm and the lower arm is provided at two outer ends spaced apart from each other in the vehicle front-rear direction. A double-wishbone type rear suspension, which is an H-shaped arm pivotally supported by a carrier and pivotally supported on a vehicle body by elastic bushes at two inner ends spaced apart from each other in the vehicle front-rear direction, has been already known. ing.

FIG. 6 is a schematic perspective view showing an example of a double wishbone type rear suspension as described above as a skeleton diagram. In FIG. 6, the shock absorber and the suspension spring are omitted. Figure 6
In the figure, 10 indicates a carrier that rotatably supports the wheel 12 around a rotation axis 12A, and 14 and 16 indicate upper and lower arms, respectively. In the illustrated example, the upper arm 14 is an I-shaped arm and the lower arm 16 is an H-shaped arm.

The upper arm 14 has its outer end pivotally attached to the upper end of the carrier 10 by a ball joint 18, and has its inner end pivotally supported on a vehicle body 22 by a joint 20 including a rubber bush. Similarly, the lower arm 16 has joints 24, 2 at two outer ends spaced apart from each other in the vehicle front-rear direction.
A pair of rubber bushes at two inner ends which are pivotally attached to the lower end of the carrier 10 so as to be pivotable about a pivot line 28 defined by their centers and which are spaced from each other in the vehicle longitudinal direction. The joints 30 and 32 are pivotally supported on the vehicle body 22 about a pivot line 34 defined by their centers.

According to the rear suspension having such a structure, the lower arm is an H-shaped arm, and the lower arm and the carrier are substantially relative to the vehicle body even if a longitudinal force acts on the wheels 12 during acceleration and deceleration of the vehicle. Since it does not pivot in the front-back direction, the front-rear rod required when both the upper arm and the lower arm are I-arms can be omitted.

[0006]

However, in the conventional double wishbone type rear suspension having the H-shaped lower arm as described above, the joints 24 and 26 at the two outer ends of the lower arm 16 are ball joints or rubber bushes. In any of the joints including these, there may be backlash due to manufacturing tolerances and the like in these joints. Therefore, as shown in FIG. Even if is applied, a low-rigidity region in which the relative displacement δ in the vehicle lateral direction between the outer end of the lower arm and the carrier fluctuates relatively large may occur.

When such a low rigidity region is generated, the lateral rigidity of the suspension, particularly the initial lateral rigidity (lateral rigidity immediately after the lateral force F acts on the ground contact point of the wheel) is lowered, and the steering stability of the vehicle is deteriorated. There is.

In view of the above-mentioned problems in the conventional double wishbone type rear suspension having the H-shaped arm, the present invention improves the steering stability of the vehicle because the suspension has a higher initial lateral rigidity than the conventional one. The objective is to provide an improved double wishbone rear suspension.

[0009]

SUMMARY OF THE INVENTION According to the present invention, the above-described object is achieved by a carrier for rotatably supporting a wheel, an outer end of which is pivotally attached to the carrier, and an inner end of which is pivotally supported by a vehicle body. An upper arm, and a lower arm pivotally attached to the carrier at two outer ends spaced apart from each other in the vehicle front-rear direction and pivotally supported on the vehicle body at two inner ends spaced apart from each other in the vehicle front-rear direction, An assist link pivotally attached to the carrier at the outer end and pivotally supported by the vehicle body at the inner end, the assist link providing an urging force between the carrier and the vehicle body along the axis thereof. This is achieved by a vehicle rear suspension that is characterized by being configured.

[0010]

According to the above-mentioned structure, the assist link pivotally attached to the carrier at the outer end and pivotally supported on the vehicle body at the inner end is provided, and the assist link is provided between the carrier and the vehicle body along its axis. Is configured to provide a biasing force to the lower arm, and therefore the carrier is pivotally biased to the two outer ends of the lower arm around the pivot point with the upper arm by the biasing force of the assist link. Even if there is backlash in the pivotal connection between the outer ends of the two carriers and the carrier, the backlash is absorbed, thereby improving the initial lateral rigidity of the suspension and improving the steering stability of the vehicle as compared with the prior art.

[0011]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

1 and 2 are schematic perspective views and plan views showing one embodiment of a vehicle rear suspension according to the present invention as skeleton diagrams, and FIG. 3 is FIG. 1 and FIG.
FIG. 3 is a side view showing the carrier in the embodiment shown in FIG. 1 as viewed from the inboard side of the vehicle. In these figures, the shock absorber and the suspension spring are omitted, and the parts corresponding to those shown in FIG. 6 are designated by the same reference numerals as those shown in FIG. There is.

In these drawings, reference numeral 10 denotes a carrier for rotatably supporting a wheel 12 about a rotation axis 12A, and 14 and 16 respectively, an upper arm and a lower arm extending substantially in the lateral direction of the vehicle. Is shown. As shown, the upper arm 14 is an I-shaped arm and the lower arm 16 is an H-shaped arm.

The upper arm 14 is pivotally attached to the upper end of the carrier 10 by a ball joint 18 at the outer end, and is connected to the vehicle body 22 by a joint 20 including a rubber bush at the inner end.
Is pivoted to. Similarly, the lower arm 16 is pivotally attached to the lower end of the carrier 10 by ball joints 24 and 26 at the outer ends, and a pair of joints 3 including rubber bushes at the two inner ends that are substantially separated from each other in the vehicle longitudinal direction.
It is pivotally supported on the vehicle body 22 about an axis 34 bounded by their centers by 0, 32.

As shown in FIGS. 1 and 2, an assist link 36 extending substantially in the lateral direction of the vehicle is disposed on the front side of the vehicle from the ball joint 24 and the rotation axis 12A. The assist link 36 is pivotally attached to the carrier 10 at a joint 38 including a rubber bush at an outer end, and a joint 40 including a rubber bush at an inner end.
Is pivotally attached to the vehicle body 22 by. Further, as shown in FIG. 4, the assist link 36 has a turnbuckle 42, and after being connected between the carrier 10 and the vehicle body 22, its length is increased / decreased to extend along its axis 44. A preload Fo is provided between the carrier and the vehicle body as a biasing force of compression or tension.

In the illustrated embodiment, as shown in FIG. 2, the joints 32 and 26 are substantially aligned with each other laterally of the vehicle, but the joint 30 is more forward of the vehicle than the joint 24. It is located in. Further, the joint 38 at the outer end of the assist link 36 is connected to the upper arm 14.
Is located on the front side of the vehicle relative to the ball joint 18 on the outer end of the vehicle and the ball joint 24 on the front side of the vehicle on the outer end of the lower arm 16, and as shown in FIG. A straight line 46 connecting the centers of the ball joint 18 at the outer end and the joint 38 at the outer end of the assist link 36 intersects with the axis 28 connecting the centers of the ball joints 24 and 26 at the outer ends of the lower arm 16 with the intersection point P.
Intersect with each other.

Further, in the illustrated embodiment, as shown in FIG. 2, the distance between the intersection P and the joint 30 in the vehicle front-rear direction is Lf, and the vehicle front-rear between the intersection P and the joint 32 is shown. If the distance Lr in the direction and the spring constants of the ball joints 30 and 32 at the inner ends of the lower arm 16 in the vehicle lateral direction are Rf and Rr, the distances Lf and Lr are set to satisfy the following relationship.

Lf: Lr = Rr: Rf As shown in FIG. 1, the vertical distance between the center of the ball joint 18 and the center of the joint 38 is L ₁
And the vertical distance between the center of the ball joint 18 and the centers of the ball joints 24 and 26 is L _2, and the center of the ball joint 18 and the grounding point P of the wheel 12 are
Let L ₃ be the vertical distance between the carrier 10 and the carrier 10.
Since the preload Fo is applied between the vehicle body 22 and the vehicle body 22 by the assist link 36, the ball joints 24 and 2
The 6 Fo '= preload of _{Fo · (L 1 / L 2} ) is applied. Lateral force Fo "to the ground point P of the wheels on the ball joints 24 and 26 in other words _{= Fo · (L 1 / L} 2) · (L 2 / L 3) = Fo · (L 1 / L 3) is When it works, the preload corresponding to it works.

As shown in FIG. 5, in the conventional rear suspension, when the lateral load F fluctuates within the range of ± Fs, the relative lateral displacement δ between the outer end of the lower arm and the carrier is a non-linear characteristic. In the illustrated embodiment, the relative displacement δ fluctuates only slightly in the range of the linear characteristic, for example, δi, while the wheel displacement varies relatively in the range of δc. The initial lateral rigidity of the suspension can be made extremely high with respect to the lateral load F acting on the ground contact point of the vehicle, which can improve the steering stability of the vehicle.

According to the illustrated embodiment, as described above,
A straight line 46 connecting the centers of the ball joint 18 at the outer end of the upper arm 14 and the joint 38 at the outer end of the assist link 36 as viewed in the lateral direction of the vehicle is a straight line 28 connecting the centers of the ball joints 24 and 26 at the outer ends of the lower arm 16. Intersect with each other at the intersection point P, and the distances Lf and Lr are L
Since the relationship of f: Lr = Rr: Rf is satisfied, the forces exerted on the joints 30 and 32 by the biasing force of the assist link on the carrier are substantially equal to each other, and thus the assist link is set. It is possible to avoid that the addition of the above affects the toe and toe change characteristics of the wheel.

In the above-described embodiment, the assist link 36 has its length increased or decreased by the turnbuckle 42 so that the carrier 10 and the vehicle body 2 are aligned along the axis 44 thereof.
Preload F as a urging force of compression or tension between 2 and
However, it may be of any structure as long as it can provide a compressive or tensile biasing force between the carrier and the vehicle body along the axis.

Although the present invention has been described above in detail with reference to specific embodiments, the present invention is not limited to such embodiments, and other various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art that it is possible.

[0023]

As is apparent from the above description, according to the present invention, the carrier is pivotally attached to the two outer ends of the lower arm around the pivot point with the upper arm by the urging force along the axis of the assist link. Even if there is rattling in the pivotal connection between the two outer ends of the lower arm and the carrier, the rattling is absorbed, improving the initial lateral rigidity of the suspension compared to the conventional model. As a result, the steering stability of the vehicle can be improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing, as a skeleton diagram, one embodiment of a vehicle rear suspension according to the present invention.

FIG. 2 is a plan view showing the embodiment shown in FIG. 1 as a skeleton diagram.

FIG. 3 is a side view showing the carrier in the embodiment shown in FIG. 1 as seen from the inboard direction of the vehicle.

FIG. 4 is a plan sectional view showing an example of the assist link shown in FIG.

FIG. 5 is a graph showing lateral rigidity of a conventional double wishbone type rear suspension and the illustrated embodiment.

FIG. 6 is a schematic perspective view showing an example of a conventional double wishbone type rear suspension as a skeleton diagram.

[Explanation of symbols]

 10 ... Carrier 14 ... Upper Arm 16 ... Lower Arm 18 ... Ball Joint 20 ... Joint 22 ... Vehicle Body 24, 26 ... Ball Joint 30, 32 ... Joint 36 ... Assist Link 38 ... Ball Joint 40 ... Joint 42 ... Turnbuckle

Claims (1)

[Claims] 1. A carrier for rotatably supporting a wheel, an upper arm pivotally attached to the carrier at an outer end and pivotally supported on a vehicle body at an inner end, and two outer members spaced from each other in a vehicle front-rear direction. A lower arm pivotally supported on the vehicle body at two inner ends that are pivotally attached to the carrier at the ends and are spaced apart from each other in the vehicle longitudinal direction, and a lower arm pivotally attached to the carrier at the outer end to the vehicle body at the inner end. A rear suspension for a vehicle, comprising a pivotally supported assist link, wherein the assist link is configured to apply a biasing force between the carrier and the vehicle body along an axis thereof.