JP3082406B2 - Rear suspension - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automobile rear suspension.

[0002]

2. Description of the Related Art FIG. 1 is a conceptual perspective view of a rigid axle type rear suspension.

[0003] The rotational driving force from the drive shaft DS is a differential device D
It is transmitted to the rear wheel axle RA via F and rotationally drives a rear wheel (not shown).

The rear wheel axle RA is rotatably fixed at a point P2 to a pair of left and right trailing rods TR which are rotatably fixed to a vehicle body (not shown) at a point P1.
Further, the rear wheel axle RA is fixed to a pair of springs SP fixed to the vehicle body at a point P3 and a shock absorber (not shown) near the point P2.

The longitudinal force between the rear wheel axle RA and the vehicle body is transmitted to each other via a trailing rod TR, and the vertical force is transmitted via a spring SP and a shock absorber.

FIG. 2 is a conceptual side view of a rigid axle suspension having the structure shown in FIG. 1 for explaining the wind-up torque acting on the vehicle body when the vehicle is driven or braked.

In this case, for example, when the drive shaft DS rotates in the direction of arrow a and the rear wheel shaft RA rotates in the direction of arrow b,
A wind-up rotational force acts on the vehicle body in the direction of arrow W via the trailing rod TR. As a result, the reaction at the time of starting or braking becomes slow, and vibration may occur.

FIG. 3 is a conceptual rear view of this suspension showing the state of the suspension of FIG. 1 at the time of turning.

When the vehicle turns, a centrifugal force acts to deform the spring SP shown by the solid line as the spring SP shown by the dotted line.

FIG. 4 shows an example of a rear suspension according to the prior art.

The rotational driving force from the drive shaft DS is applied to the differential device D.
The rotation is transmitted to the rear wheel axle RA via F to rotate the rear wheel TY.

The rear wheel axle RA is rotatably fixed at a point P2 to a pair of left and right trailing rods TR rotatably fixed at a point P1 to a vehicle body (not shown).
Further, the rear wheel axle RA is fixed near a point P2 to a pair of springs SP fixed to the vehicle body at a point P3. The shock absorber SA is provided in parallel with the spring SP.

The differential DF is connected to the vehicle body via a center wishbone arm CW. That is, the center wishbone arm CW is provided rotatably about a pair of rotation centers Q1 and Q2 about the lateral direction of the vehicle body, and the center wishbone arm and the differential gear D are provided.
F is connected by a ball joint at point Q3.

The front-rear force between the rear wheel axle RA and the vehicle body is transmitted to each other via a trailing rod TR, and the vertical force is transmitted to each other via a spring SP and a shock absorber SA. It is similar to the suspension of FIG.

FIG. 5 is a conceptual side view of the suspension of FIG. The trailing rod TR is rotatably fixed to the vehicle body at the point P1, the rear wheel shaft is rotatably fixed to the trailing rod TR at the point P2, and the center wishbone arm CW is rotated around the vehicle body at the points Q1 and Q2. The actuator DF is movably fixed to the center wishbone arm CW at a point Q3 with a ball joint.

The distance d between the point P1 and the points Q1 and Q2, the point Q
1, the distance between Q2 and point Q3, the distance between points P1 and P2, and the height h of point Q3 with respect to point P2 are constant,
Points P1, P2, Q1, and Q3 in the plane of FIG. 5 form a kind of four-node link mechanism. The distance between points P1 and P2, point Q1,
By adjusting the distance or the like between Q2 and point Q3, even if the wind-up rotating power works when the rear wheel axle is driven or braked, the effect can be reduced.

FIG. 6 is a conceptual rear view of the suspension of FIG. The rear axle is connected to the point Q3 on the upper part of the differential device DF via the center wishbone arm CW.
At 1 and Q2, it is fixed to the vehicle body.

Therefore, the influence of the centrifugal force which tends to deform as shown in FIG. 3 during turning can be reduced.

[0019]

In the suspension shown in FIG. 4, the center of the rolling of the rear wheel axle RA is the point Q3. On the other hand, in the suspension shown in FIG. 4, the center wishbone arm C
W is coupled to the top of differential DF. In order to reduce the influence of the windup rotational force and to reduce the influence of the centrifugal force, the point Q with respect to the rear wheel axis RA is set.
The height h of 3 is preferably high. This means that the rolling center is high.

The present invention has a high windup rigidity,
An object of the present invention is to propose a rear suspension in which the influence of centrifugal force during turning is small and the rolling center is low.

[0021]

An object of the present invention is to solve the above problem by enclosing a rotating shaft substantially parallel to a rear wheel axle so that one end is rotatably fixed to a vehicle body and the other end is rotatably connected near both ends of the rear wheel axle. A pair of trailing rods and a pair of springs, one end of which is fixed to the vehicle body and the other end of which is connected near both ends of a rear wheel axle, a plurality of pivots on one axis parallel to the rear wheel axle And a center wishbone arm fixed to the vehicle body so as to be rotatable around the center, and an upper vertex, which is one vertex of the triangle, being parallel to the rotation axis of the center wishbone arm. A pair of A-shaped arms fixed at two points on a straight line by ball joints, and the other two vertices of each A-shaped arm, namely a lower vertex, are arranged in the front-rear direction of the vehicle;
These lower vertices are fixed to the cover of the rear wheel axle so as to be rotatable about a rotation axis substantially parallel to the front-rear direction of the vehicle, and straight lines connecting the upper and lower vertices of each A-shaped arm intersect with each other. The problem is solved by the rear suspension, which is characterized in that the position of the rear suspension is located below the ball joint.

In a preferred embodiment of the present invention, each A
The L-shaped arm is fixed to the cover of the rear wheel axle by being rotatably fixed to the differential.

In another embodiment of the present invention, a pair of A
A-shaped arms are integrally formed, and two vertices of each A-shaped arm are fixed to the rear wheel axle cover so as to be rotatable around a common rotation axis.

[0024]

[Work] In addition to the rear wheel axle being rotatably fixed to a pair of trailing rods, it is also rotatably fixed to the vehicle body via a center wishbone arm and an A-shaped arm at other points. Therefore, for the same reason as the suspension of FIG. 4, the wind-up rigidity is large, and the influence of the centrifugal force during turning is small.

In the present invention, the center wishbone arm is not directly connected to the rear wheel axle, but is connected via a pair of A-shaped arms. At this time, the rolling center is a straight line where a plane including three vertices of both A-shaped arms intersects.

In the present invention, the straight line is disposed so as to pass below the ball joint at the joint between the two A-shaped arms and the center wishbone arm. This means that the center of rolling of the rear suspension of the present invention is lower than in the prior art. Thereby, it is possible to avoid a problem caused by a high rolling center.

FIG. 7 is a conceptual perspective view of a preferred embodiment of the rear suspension of the present invention. The rear suspension of FIG. 7 is an improvement of the rear suspension of FIG. Therefore, there are common members. In order to simplify the description, members common to both are denoted by common reference numerals, and description thereof is omitted.

One side of the substantially rectangular center wishbone arm CW is fixed to the vehicle body so as to be rotatable about a plurality of rotation axes Q1 and Q2 on one axis parallel to the rear wheel axis RA.

FIG. 8 shows a center wishbone arm C.
It is a perspective view of W. A pair of holes is formed along a side parallel to the side where the rotation axes Q1 and Q2 are provided. This hole is provided not at right angles to the upper surface of the center wishbone arm CW but at a slight angle for a reason described later.

Each A-shaped arm A which is a substantially triangular A-shaped
The upper vertices R1 and R2, which are one of the vertices, are connected to the center wishbone arm CW via the ball joint BJ.
At the hole.

FIG. 9 is a cross-sectional view of the connection between the A-shaped arm A and the center wishbone arm CW by the ball joint BJ. Since they are connected by the ball joint BJ, the coordination relationship between them is relatively free.

The other two vertices of each A-shaped arm A, lower vertices R3, R4 and R5, R6 are respectively arranged in the front-rear direction of the vehicle, and these lower vertices are rotated substantially parallel to the front-rear direction of the vehicle. It is fixed to the differential DF so as to be rotatable about an axis. In FIG. 7, the lower vertices R4 and R6 are not visible.

In FIG. 7, the tops of the A-shaped arms A are arranged such that a straight line L where planes including the three vertices intersect each other is located below the rear wheel axis RA and descends in the forward direction of the vehicle. R3, R4 and R5, R6 are vertices R1,
It is arranged on the inner side in the left-right direction of the vehicle body than R2.

[0034] Correspondingly, two holes of the center wishbone arm CW are also provided to be inclined.

FIG. 10 is an enlarged perspective view of the apex R5 of the A-shaped arm A and the fixed portion of the differential gear DF. A rubber bush RB is provided between the differential DF and the apex R5 of the A-shaped arm A.
Is arranged.

FIG. 11 is a conceptual side view of the suspension of FIG.

As in FIG. 5, the trailing rod TR is rotatably fixed to the vehicle body at the point P1, the rear wheel shaft is rotatably fixed to the trailing rod TR at the point P2, and the center wishbone arm CW Are rotatably fixed to the vehicle body at points Q1 and Q2.

In FIG. 11, unlike FIG. 5, the center wishbone arm CW and the differential gear DF are connected via an A-shaped arm A.

Center wishbone arms CW and A
The A-shaped arm A is connected by a ball joint at the point R1, and the A-shaped arm A and the differential are connected at points R3 and R4.
Are connected by two rotating shafts.

In the plane of FIG. 11, the positional relationship between the differential device DF and the A-shaped arm A cannot be changed, and the A-shaped arm A and the differential device DF move integrally in this plane. This means that FIGS. 11 and 5 are equivalent in this plane.

Accordingly, the effect that the influence of the wind-up rotating power when the rear wheel axle is driven or braked is small is also obtained.

FIG. 12 is a conceptual rear view of the suspension of FIG. The rear axle is located at the upper point R3, R
At 4 and R5, R6, it is connected to the center wishbone arm CW via the A-shaped arm A.

Therefore, the points R1, R3, R5, R
Center wishbone arm CW2 connected by 2
The A-shaped arms A and the rear wheel axle form a kind of four-bar linkage. Therefore, the influence of the centrifugal force to be deformed as shown in FIG. 3 during turning is smaller than in the case of FIG.

FIG. 13 shows the rolling center RC of the center wishbone arm CW when the two A-shaped arms A rotatably fixed at points R3 and R5 on the rear wheel axle, that is, the rolling center RC of the vehicle body. FIG. 7 as viewed from a plane including both A-shaped arms for illustrating the position.
FIG. 2 is a conceptual rear view of the suspension of FIG.

The rolling center RC, which is the instantaneous center of the rolling, is the intersection point RC of a straight line obtained by extending the two A-shaped arms A. The fact that the intersection point RC is the instantaneous center of rolling can be explained by applying the three instantaneous center theorem to the four-bar rotation chain mechanism.

In other words, the vertices R3 and R5 of the two A-shaped arms A are circles C centered on the points R1 and R2.
1, move on C2. Instantly, the circles C1 and C2 are perpendicular to the straight line connecting the point RC and the point R1 and the straight line connecting the point RC and the point R2, respectively. That is, the vertices R3 and R5 move on an arc centered on RC. This is because when the point R3 and the point R5 slightly move to the point R3a and the point R5a, respectively,
The straight line connecting the point R3 and the point R3a and the straight line connecting the point R5 and the point R5a mean that they are perpendicular to the straight line connecting the point R3 and the point RC and the straight line connecting the point R5 and the point RC, respectively. Point R3
And the distance between point R5 and the distance between point R3a and point R5a are equal. Therefore, the point RC becomes the instantaneous rolling center.

In the suspension shown in FIG. 7, the rolling center RC thus obtained is located below the rear wheel axle. Therefore, the problem caused by the high rolling center RC can be avoided.

FIG. 14 shows the rear suspension A of the present invention.
It is a side view at the time when the straight line L which connects the rolling center by a character-shaped arm inclines back and forth.

In this case, the rear side of the left and right A-shaped arms, that is, the side connecting the vertices R1 and R3, and the vertex R2
The height of the fulcrum RC1 of the extension of the side connecting R5 and R5 is the front side of the left and right A-shaped arms, that is, the vertices R1 and R4.
Is higher than the height of the intersection point RC2 of the side connecting the vertices R2 and R6. That is, the straight line connecting the intersections RC1 and RC2 is inclined by the angle α with respect to the horizontal line H.

The straight line connecting the intersections RC1 and RC2 is descending forward with respect to the horizontal line H. Therefore, in FIG. 14, for example, when the tire on the left side of the rear wheel axis RA perpendicular to the paper surface rides on the bump, the tire on the left side rotates around the straight line L so as to advance in the forward direction of the vehicle. The trajectory is perpendicular to the straight line L. Therefore, the rear wheel slip angle is formed inside the turning, and the stability of the rear wheel is high.

Since the axle-side rotating shaft of the A-arm is tilted forward, the bump-side wheels tend to move forward and the rebound-side wheels try to move backward when rolling. Therefore, when rolling, the trailing rod is compressed on the bump side and stretched on the rebound side, deforming the bush,
The reaction force produces an anti-roll effect.

FIG. 15 shows the rear suspension A of the present invention.
FIG. 10 is a perspective view of another embodiment of the character-shaped arm. In this case, A
The arm AA has a vertex R3 and R5 in FIG.
7, and vertices R4 and R6 are combined with another vertex R8.
And attached to the differential DF.

Since the rolling center is on the straight line connecting the vertices R7 and R8, it is higher than in FIG. 7 but lower than in FIG.

This embodiment has an advantage that the number of parts is small.

[0055]

【The invention's effect】

1) It is possible to achieve both the securing of the wind-up rigidity and the reduction of the roll center height. 2) Since the wheel trajectory at the time of both-wheel bump and the wheel trajectory at the time of one-side bump can be set independently, the rear wheel slip angle and the anti-roll effect can be set optimally. 3) Since the degree of freedom in dimension is higher than that of the prior art, the degree of freedom in changing the differential angle, optimizing the axle steer and the roll center is high, and the straightness, design, steering stability, and riding comfort are improved. Can be improved. 4) Since the lateral rod is unnecessary, the space behind the rear axle is free, and the bracket on the vehicle body side can be omitted.

[Brief description of the drawings]

FIG. 1 is a conceptual perspective view of a rigid axle type rear suspension.

FIG. 2 is a conceptual side view of the rigid axle suspension having the structure shown in FIG. 1, illustrating a wind-up torque acting on a vehicle body when the vehicle is driven or braked.

FIG. 3 is a conceptual rear view of the suspension of FIG. 1 showing a state of the suspension during a turn.

FIG. 4 is a conceptual perspective view of an example of a conventional rear suspension.

FIG. 5 is a conceptual side view of the suspension of FIG. 4;

FIG. 6 is a conceptual rear view of the suspension of FIG. 4;

FIG. 7 is a conceptual perspective view of a preferred embodiment of a rear suspension according to the present invention.

FIG. 8 is a perspective view of a center wishbone arm CW.

FIG. 9 is a cross-sectional view of a connection portion of the A-shaped arm A and the center wishbone arm CW by a ball joint BJ.

FIG. 10 is an enlarged perspective view of a vertex R5 of the A-shaped arm A and a fixing portion of the actuator DF.

FIG. 11 is a conceptual side view of the suspension of FIG. 7;

FIG. 12 is a conceptual rear view of the suspension of FIG. 7;

FIG. 13 shows two A-shaped arms for explaining the position of a rolling center RC of a center wishbone arm CW when two A-shaped arms A rotatably fixed at points R3 and R5 on a rear wheel axle move. FIG. 7 viewed from the plane including the arm
FIG. 2 is a conceptual rear view of the suspension of FIG.

FIG. 14 is a side view of the rear suspension according to the present invention when the rolling center formed by the A-shaped arm is inclined forward and backward.

FIG. 15 is a perspective view of another embodiment of the A-shaped arm of the rear suspension of the present invention.

[Explanation of symbols]

 A, AA A-shaped arm RJ Ball joint CW Center wishbone arm DF Differential device H Horizontal line L Straight line including roll center Q1, Q2 Rotation axis R1, R2 ... R8 A-shaped arm vertex R, A Rear wheel axis RB Rubber bush RC Roll center SA Shock absorber SP Spring T1, T2 Trajectory TR Trailing rod TY Tire

Claims (3)

(57) [Claims] 1. A pair of trailing rods, one end of which is rotatably fixed to a vehicle body around a rotation shaft substantially parallel to the rear wheel shaft, and the other end of which is rotatably connected near both ends of the rear wheel shaft. A rear suspension having a pair of springs, one end of which is fixed to the vehicle body and the other end of which is connected near both ends of a rear wheel axle, wherein the vehicle body is rotatable around a plurality of rotation axes on one axis parallel to the rear wheel axle. A center wishbone arm fixed to the center joint and a ball joint at two points on a straight line parallel to the rotation axis of the center wishbone arm at the upper vertex, which is one vertex of the triangle. And a pair of A-shaped arms fixed by the following, and the other two vertices of each A-shaped arm, the lower vertices, are arranged in the longitudinal direction of the vehicle, and these lower vertices are turned substantially parallel to the longitudinal direction of the vehicle. The point at which the straight lines connecting the upper apex and the lower apex of each A-shaped arm intersect with each other is fixed below the ball joint so as to be rotatable about the drive shaft. And rear suspension. 2. The rear suspension according to claim 1, wherein the A-shaped arm is fixed to a cover of a rear wheel axle by being rotatably fixed to the differential. 3. The pair of A-shaped arms are integrally formed, and two vertices of each A-shaped arm are fixed to a cover of a rear wheel shaft so as to be rotatable around a common rotation axis. The rear suspension according to claim 1, wherein: