JPH0672116A - Double wishbone type suspension - Google Patents

Abstract

PURPOSE:To prevent a caster angle and caster trail from largely decreasing when wheels receive a rearward force from a road surface. CONSTITUTION:A suspension has an upper arm 14 connected pivotably to a wheel carrier at the outer end and shaft-supported through a rubber bushing by a carbody at the inner end, a lower arm 16 connected pivotably at the outer end to a wheel carrier and shaft-supported by the car body through a pair of rubber bushings at the two inner ends spaced from each other back and forth, and a connecting link 44 connected pivotably to the upper arm at the upper end and connected pivotably to the lower arm at the lower end. The connecting link extends obliquely to at least back and forth of the wheel to transmit the rearward displacement of the lower arm to the upper arm.

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 double wishbone type suspension.

[0002]

2. Description of the Related Art As one of double-wishbone type suspensions for vehicles such as automobiles, for example, the actual opening 63-
As described in Japanese Patent No. 306908, a carrier that rotatably supports a wheel and an elastic bush at two inner ends that are pivotally attached to the carrier at the outer ends and are substantially separated from each other in the vehicle longitudinal direction are provided. A double-wishbone type suspension having an upper arm and a lower arm pivotally supported by a vehicle body through the suspension is well known in the art.

FIG. 4 is a schematic perspective view showing an example of the double wishbone type suspension as described above as a skeleton diagram. In FIG. 4, the shock absorber and the suspension spring are omitted. In FIG. 4, reference numeral 10 denotes a carrier that rotatably supports the wheel 12 around a rotation axis 12A, and reference numerals 14 and 16 denote an upper arm and a lower arm, respectively. In the illustrated example, both the upper arm and the lower arm are A-type arms.

The upper arm 14 is pivotally attached to the upper end of the carrier 10 by a ball joint 18 at its outer end, and has a pair of joints 20 including rubber bushes at its two inner ends substantially separated from each other in the vehicle longitudinal direction. It is pivotally mounted by means of 22 about their common axis 24 to a vehicle body not shown in the drawing. Similarly, the lower arm 16 is pivotally attached to the lower end of the carrier 10 by a ball joint 26 at the outer end, and a pair of joints 28, 30 including rubber bushes at the two inner ends substantially separated from each other in the vehicle front-rear direction. Are pivotally supported on the vehicle body so as to be pivotable about their common axis 32. The carrier 10 is integrally provided with a knuckle arm 34, and one end of a tie rod 38 is pivotally attached to the tip of the knuckle arm by a ball joint 36.

[0005]

In the conventional double wishbone type suspension as described above, as shown in FIG. 5, the wheel 12 has the road surface due to the braking force at the time of vehicle braking and the unevenness of the road surface. When a vehicle rearward force Fb is applied from 40, the carrier 10 pivots counterclockwise as viewed in FIG. 6, so that the ball joint 26 receives the vehicle rearward force F ₁ and is moved to the position indicated by reference numeral 26 '. displaced to the ball joint 18 is displaced to the position shown by reference numeral 18 'receives the vehicle forward force F ₂ as a reaction force of F _1. As a result, the kingpin axis 42, defined as a straight line passing through the centers of the ball joints 18 and 26, is displaced to the position indicated at 42 ', which causes the caster trail Ct to move to C.
As the caster angle θc is reduced to θc ′ with the decrease to t ′, the straightness of the vehicle deteriorates.

Further, when the vehicle turns, as shown in FIG. 6, a cornering force Fc acts on the wheels 12, and when the vehicle turns with braking, the force component Fcb of the rearward force of the cornering force Fc is applied. However, since the same phenomenon as that described above is caused, the caster trail and the caster angle are reduced, and the feel of the steering wheel during turning is deteriorated.

In view of the above-mentioned problems in the conventional double wishbone suspension, the present invention prevents the caster angle and the caster trail from being greatly reduced even when the wheels receive a rearward force from the road surface of the vehicle. It aims to provide an improved double wishbone suspension.

[0008]

SUMMARY OF THE INVENTION According to the present invention, the above object is achieved by a carrier for rotatably supporting a wheel and an elastic bush at an inner end pivotally attached to the carrier. An upper arm pivotally supported on the vehicle body, and two inner ends that are pivotally attached to the carrier at the outer ends and are spaced from each other substantially in the vehicle longitudinal direction, and are pivotally supported at the vehicle body through a pair of elastic bushes. It has a lower arm and a connecting link pivotally attached to the upper arm at the upper end and pivotally attached to the lower arm at the lower end, and the connecting link extends at least inclined in the vehicle longitudinal direction. It is achieved by a double wishbone suspension.

[0009]

According to the above-mentioned structure, the connecting link is pivotally connected between the upper arm and the lower arm, and the connecting link extends at least in the vehicle front-rear direction, so that the wheels are connected to the road surface. When the lower arm is pivoted relative to the vehicle body so that the outer end of the upper arm moves rearward of the vehicle by receiving a rearward force from the vehicle, the upper arm is also attached to the vehicle body by a connecting link so that the outer end of the lower arm moves rearward of the vehicle. It is pivoted relative to one another, which reduces the amount by which the caster trail and caster angle are reduced.

[0010]

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

FIG. 1 is a schematic perspective view showing one embodiment of a double wishbone suspension according to the present invention as a skeleton diagram, and FIG. 2 is a partial cutaway of the main part of the embodiment shown in FIG. FIG. In these figures, the shock absorber and the suspension spring are omitted, and the parts corresponding to the parts shown in FIGS. 4 to 6 have the same reference numerals as those in these figures. Is attached.

In these figures, 10 indicates a carrier for rotatably supporting the wheel 12 around a rotation axis 12A, and 14 and 16 indicate an upper arm and a lower arm, respectively. In the illustrated embodiment, the upper arm 14 is an I-arm and the lower arm 16 is an L-arm.

The upper arm 14 is pivotally attached at its outer end to the upper end of the carrier 10 by a ball joint 18 and extends substantially in the lateral direction of the vehicle and is shown in the drawing by a joint 20 including a rubber bush at its inner end. Not pivoted on the car body. Similarly, the lower arm 16 is pivotally attached to the lower end of the carrier 10 by a ball joint 26 at the outer end, and a pair of joints 28, 30 including rubber bushes at the two inner ends substantially separated from each other in the vehicle front-rear direction. Is pivotally supported about their common axis 32 on a vehicle body not shown in the drawing. In particular, in the illustrated embodiment, the front joint 28 of the lower arm 16 is located in substantially the same lateral position as the ball joint 26.

In the illustrated embodiment, the upper arm 14
An upper end of the connecting link 44 is pivotally connected to a middle portion of the lower link 16 by a ball joint 46, and a lower end of the connecting link is pivotally connected to an intermediate portion of the lower arm 16 by a ball joint 48. Ball joint 48
Are located on the vehicle rear side and slightly on the inboard side of the ball joint 46, so that the connecting link 44 is inclined in the vehicle front-rear direction and slightly in the inboard direction from the upper end toward the lower end. Has been extended.

When the lower arm 16 pivots in the vertical direction around the axis 32 due to the wheel 12 bouncing and rebounding, the inclination angle of the connecting link 44 slightly changes and the position of the ball joint 46 moves in the vehicle longitudinal direction. However, since the displacement of the ball joint 46 in the vehicle front-rear direction is absorbed by the upper arm 14 pivoting slightly around the joint 20 in the vehicle front-rear direction, the connecting link causes link interference. There is nothing to do.

Next, the operation of the embodiment configured as described above when the vehicle rearward force acts on the wheels will be described. For convenience of explanation, as shown in FIG. 2, the distance between the center of the ball joint 26 and the center of the joint 28 is L _1, and the center of the joint 28 and the joint 3 are
Let L ₂ be the distance from the center of 0 and L ₃ be the distance between the center of the joint 28 and the center of the ball joint 48. Similarly, the distance between the center of the ball joint 18 and the center of the joint 20 is L _4, and the distance between the joint 20 and the center of the ball joint 46 is L ₅ . Further, when viewed from above the vehicle, the axis of the connecting link 44 forms an angle θ ₁ with a straight line perpendicular to the straight line 50 connecting the center of the ball joint 48 and the center of the joint 28, and the axis of the connecting link is The angle made with respect to the vehicle longitudinal direction is θ ₂ .

As shown in FIGS. 2 and 3, a rearward vehicle force F ₁ acts on the ball joint 26 at the outer end of the lower arm 16 so that the lower arm joins the joint 2.
8 pivoted relatively in the vehicle rear relative to the vehicle body around the and thereby the ball joint 26 and displaced to .delta.o vehicle rearward, the joint 30 is _{δ 1 = δo · (L 2} / L 1) inboard direction And the joint 48 is displaced in the rearward direction of the vehicle and in the inboard direction perpendicular to the δ ₂ = δ o. (L ₃ / L ₁ ) straight line 50.

[0018] Thus the ball joint 46 _{δ 3 = δ 2 · (cos} δ 1 / cos δ 2) displaced to the vehicle rearward, thereby the upper arm 14 is vehicle rear directed force F ₂ from the connecting link 44 at the ball joint 18 as viewed in FIG. 2 relative pivoting with respect to the vehicle body in the clockwise direction by receiving the ball joint 18 _{δ 4 = δ 3 · (L} 4 / L 5) = δo · (L 3 / L 1)・ (Cos δ ₁ / cos δ ₂ ) ・ (L ₄ / L ₅ ) Displace to the rear of the vehicle.

Therefore, as shown in FIG. 3, the kingpin shaft 42 is displaced to the position shown by the reference numeral 42 ', and the caster trail Ct and the caster angle .theta.c are smaller than those in the conventional case shown in FIG. The degree of reduction is reduced, which reduces or avoids the deterioration of the straightness of the vehicle and the feeling of the steering wheel when turning.

Although the connecting link 44 is arranged on the vehicle rear side with respect to the upper arm 14 in the above-described embodiment, the connecting link may be arranged on the vehicle front side with respect to the upper arm. In the illustrated embodiment, both ends of the connecting link are pivotally attached to the upper arm and the lower arm by ball joints, but at least one of the upper end and the lower end of the connecting link is pivotally attached to the corresponding arm by a joint including a rubber bush. May be done.

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.

[0022]

As is apparent from the above description, according to the present invention, the lower arm is moved relative to the vehicle body so that the outer end of the lower arm moves rearward of the vehicle when the wheel receives a rearward force from the road surface. When pivoted, the upper arm is pivoted relative to the vehicle body so that the outer end of the upper arm moves rearward of the vehicle by the connecting link, so that the caster trail and caster wheels are supported even when the wheels are subjected to the vehicle rearward force from the road. It is possible to prevent the corner from being greatly reduced, and thereby to prevent the straightness of the vehicle from being deteriorated and the feel of the steering wheel when turning to be prevented from being deteriorated.

[Brief description of drawings]

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

FIG. 2 is a plan view showing a main part of the embodiment shown in FIG.

FIG. 3 is a schematic side view showing changes in caster angle and caster trail that occur when a wheel receives a vehicle rearward force from a road surface in the illustrated embodiment.

FIG. 4 is a schematic perspective view showing an example of a conventional double wishbone suspension as a skeleton diagram.

FIG. 5 is a schematic side view showing changes in caster angle and caster trail that occur when a wheel receives a vehicle rearward force from a road surface in a conventional double wishbone suspension.

FIG. 6 is a schematic plan view showing a cornering force generated when a vehicle turns in a conventional double wishbone suspension and a vehicle rearward force resulting therefrom.

[Explanation of symbols]

 10 ... Carrier 14 ... Upper Arm 16 ... Lower Arm 18 ... Ball Joint 20, 22 ... Joint 26 ... Ball Joint 28, 30 ... Joint 44 ... Connecting Link 46, 48 ... Ball Joint

Claims (1)

[Claims] 1. A carrier for rotatably supporting wheels, an upper arm pivotally attached to the carrier at an outer end and pivotally supported on a vehicle body at an inner end via an elastic bush, and an outer arm for the carrier. A lower arm pivotally attached to the vehicle body through a pair of elastic bushes at two inner ends that are substantially spaced apart from each other in the vehicle front-rear direction, and an upper arm that is pivotally attached to the upper arm and a lower end. A double-wishbone type suspension characterized in that it has a connecting link pivotally attached to a lower arm, and the connecting link extends obliquely at least in a vehicle front-rear direction.