JPH06106932A - Double joint suspension for steering wheels - Google Patents

Abstract

(57) [Abstract] [Purpose] To reduce the feeling of the steering wheel during steering and the deterioration of steering wheel returnability without deteriorating the durability of the rubber bush and the riding comfort of the vehicle. [Structure] A front arm 26 and a rear arm 28 which are pivotally attached to a lower end of a carrier 10 at an outer end and pivotally supported by a vehicle body 24 at an inner end. The joint 34 at the inner end of the front arm has an inner cylinder 54 and an outer cylinder 56 arranged concentrically with respect to the central axis 32 extending in the front-rear direction, and a rubber bush 58 interposed therebetween. The distance between the outer surface of the inner cylinder and the inner surface of the outer cylinder is set to be smaller at both end portions than at the central portion along the central axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension for vehicles such as automobiles, and more particularly to a double joint type suspension for steering wheels.

[0002]

2. Description of the Related Art As one of steering wheel suspensions for vehicles such as automobiles, as disclosed in, for example, Japanese Patent Publication No. 52-9889, a carrier that rotatably supports wheels and a carrier at an outer end are used. It includes a pair of suspension arms that are pivotally attached to each other and are pivotally supported by the vehicle body at the inner end and are spaced apart from each other in the vehicle front-rear direction, and the axes of the two suspension arms intersect each other on the outboard side from their outer ends. A so-called double joint type suspension configured as described above is already known.

According to such a suspension, since the kingpin axis is set at the intersection of the axes of the two suspension arms, the kingpin axis can be set regardless of the length of the arm and the like, and the kingpin axis can be set between the carrier and the suspension arm. Compared with the suspension in which the kingpin axis is set by the pivot point of, the degree of freedom in setting the kingpin axis can be increased.

[0004]

However, in the double joint type suspension, the outer ends of the two suspension arms are located away from the kingpin shaft in the inboard direction, and when the vehicle turns, the carrier does not move to the kingpin shaft. Since the two arms pivot around, the two arms pivot around the inner end on the turning outer wheel side toward the rear of the vehicle with respect to their positions when the vehicle goes straight, and on the inner end on the turning inner wheel side. The vehicle pivots around the front of the vehicle, so that the caster trail decreases on the turning outer wheel side and increases on the turning inner wheel side.

In this case, the amount of change in the caster trail increases as the steering angle increases, and the turning performance of the vehicle is more strongly influenced by the turning outer wheel side than by the turning inner wheel side. Therefore, in the double joint type suspension, there is a problem that the steering feel of the steering wheel and the returning characteristic of the steering wheel deteriorate during steering due to the decrease of the caster trail on the outer wheel side of the turning as the steering angle increases when the vehicle turns. There is.

Further, in order to reduce such a problem, if the distance between the inner cylinder and the outer cylinder of the joint at the inner end of the suspension arm is reduced and the thickness of the rubber bush is reduced to increase the spring constant, the wheel bounces. The vertical movement of the suspension arm due to the rebound is not smoothly performed, and the durability of the joint and the riding comfort of the vehicle deteriorate.

In view of the above-mentioned problems in the conventional double joint type suspension, the present invention provides a feeling of the steering wheel when steering without deteriorating the durability of the joint at the inner end of the suspension arm and the riding comfort of the vehicle. It is an object of the present invention to provide an improved double-joint suspension for steering wheels that can improve the returnability of the steering wheel and steering wheel.

[0008]

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. A double joint type for steering wheels, which includes a pair of suspension arms substantially separated in a vehicle front-rear direction, and axes of the pair of suspension arms intersect on the outboard side from the outer end when viewed from above the vehicle. In the suspension, at least one inner end of the pair of suspension arms is provided between an inner cylinder and an outer cylinder which are arranged substantially concentrically with respect to a central axis extending in the vehicle front-rear direction, and the inner cylinder and the outer cylinder. A joint including a rubber bush, one of the inner cylinder and the outer cylinder is fixed to the vehicle body, and the other of the inner cylinder and the outer cylinder is fixed to the inner end of the one suspension arm. , The distance between the outer surface and the inner surface of the outer cylinder of the inner tube is achieved by the steering-wheel double-joint type suspension, wherein small At a both end portions than the center portion along the center axis.

[0009]

According to the above-described structure, when one suspension arm pivots rearward around the joint at the inner end on the outer ring side when the vehicle turns, the rubber bush on the outboard side of the central axis of the joint. Is strongly compressed at the rear end of the vehicle and receives tensile stress at the front end of the vehicle or the degree of compression is reduced, so that the spring constant of the rubber bush is the rear end of the vehicle. , And becomes lower at the end on the front side of the vehicle, and the difference in the spring constant is at both ends rather than the center where the distance between the outer surface of the inner cylinder and the inner surface of the outer cylinder is along the central axis. Since it is small, the distance between the outer surface of the inner cylinder and the inner surface of the outer cylinder is larger than that of a conventional general joint in which the distance is substantially constant.

When a lateral force acts on the wheels in this state due to inertia during turning of the vehicle and the outer cylinder is pressed against the inner cylinder in the inboard direction, the reaction force of the rubber bush against it is the front side of the vehicle. Is higher at the rear end of the vehicle than at the end of the vehicle, resulting in the suspension arm being pivotally biased forward around its inner end, which causes The angle of rearward pivoting around the steering wheel is reduced, which reduces the reduction amount of the caster trail on the turning outer wheel side, and reduces the feel of the steering wheel during steering and the deterioration of the steering wheel returnability.

Further, according to the above-mentioned structure, the distance between the inner cylinder and the outer cylinder of the joint at the inner end of the suspension arm is reduced over their entire length, and the thickness of the rubber bush is reduced, whereby the spring constant thereof is reduced. Therefore, the suspension arm can smoothly pivot in the vertical direction as the wheels bounce and rebound, and the durability of the joint and the riding comfort of the vehicle are not deteriorated.

[0012]

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

FIG. 1 is a perspective view showing a skeleton diagram of one embodiment of a double joint type suspension according to the present invention configured as a double wishbone type suspension, and FIG. 2 is a front lower arm of the embodiment shown in FIG. It is an enlarged plan view showing a rear lower arm. In these figures, the shock absorber and the suspension spring are omitted for the purpose of simplification.

In these figures, 10 indicates a carrier for rotatably supporting the wheel 12 around a rotation axis 12A, and 14 indicates an upper arm. In the illustrated embodiment, the upper arm 14 is an A-shaped arm, and is pivoted at the outer end to the upper end of the carrier 10 by a ball joint 16 and is substantially separated from each other in the vehicle longitudinal direction. A pair of joints 1 including rubber bushes at the ends
8 and 20 are pivotally supported on the vehicle body 24 about their common axis 22.

Further, in FIGS. 1 and 2, reference numerals 26 and 28 respectively denote a front lower arm and a rear lower arm which are substantially separated from each other in the vehicle longitudinal direction. In the illustrated embodiment, the front lower arm 26 extends in the lateral direction of the vehicle, and the rear lower arm 28 is inclined forward of the vehicle when viewed from the inner end to the outer end.

The front lower arm 26 is pivotally attached to the lower end of the carrier 10 at its outer end by a ball joint 30.
It is pivotally supported on the vehicle body 24 by a joint 34 including a rubber bush having an axis 32 extending substantially in the vehicle front-rear direction at an inner end. On the other hand, the rear lower arm 28
Is a joint 4 including a rubber bush which is pivotally attached to the lower end of the carrier 10 at the outer end by a ball joint 36 and has a central axis 38 extending substantially vertically at the inner end.
It is pivotally supported on the vehicle body 24 by 0. Axis 3
2 intersects the axis 38 substantially at the center of the joint 40.

The axis 42 of the front lower arm 26, that is, the straight line connecting the center of the ball joint 30 and the center of the joint 34, is the axis 44 of the rear lower arm 28, that is, the straight line connecting the center of the ball joint 36 and the center of the joint 40. They intersect each other at an intersection P. The intersection point P is located closer to the outboard side than the ball joints 30 and 36. The intersection P and the ball joint 16 cooperate with each other to define the kingpin axis 46. A knuckle arm 48 is integrally provided on the carrier 10, and a tie rod 52 is pivotally attached to a tip end of the knuckle arm by a ball joint 50, so that when the vehicle turns, the wheels 12 are moved around the kingpin shaft 46 together with the carrier. It is supposed to be pivoted.

As shown in FIG. 2, the joint 34 at the inner end of the front lower arm 26 extends in the vehicle front-rear direction along the central axis 32 and is fixed to the vehicle body by bolts and nuts (not shown). An inner cylinder 54, an outer cylinder 56 concentrically arranged with respect to the inner cylinder and fixed to an inner end of the front lower arm, and a rubber bush 58 interposed between the inner cylinder and the outer cylinder. .

In the first embodiment shown in FIGS. 2 and 3, the inner cylinder 54 has a cylindrical shape extending along the axis 32, while the outer cylinder 56 is a vehicle. When viewed straight, the cylindrical central portion 56a extends along the axis 32 and the curved end portions 56b located on the front side and the rear side of the vehicle.
And 56c. Each end 56b and 56c
Respectively have a portion curved inward in the radial direction toward the outer end and a portion curved slightly outward in the radial direction toward the outer end, whereby a portion between the outer surface of the inner cylinder and the inner surface of the outer cylinder is formed. The distance is set smaller at both ends than at the center.

When the vehicle turns, the wheels and the carrier pivot about the kingpin axis, so that the front lower arm 26 on the turning outer wheel side as shown in FIG. 4, for example.
And the rear lower arm 28 are joints 3 at the inner ends.
Pivot back around 4 and 40. Assuming that the front lower arm 26 pivots backward about the center of the joint 34 by an angle θ, as shown in FIG.
6 also pivots about the center of the joint 34 relative to the inner cylinder 54 in the clockwise direction in the figure by an angle θ.

Therefore, the portion of the rubber bush 58 on the outboard side of the inner cylinder 54 receives high compressive stress at its rear end, and receives tensile stress at its front end. As a result, the spring constant of the rubber bush is high at the rear end of the vehicle and low at the front end of the vehicle. As described above, the distance between the outer surface of the inner cylinder and the inner surface of the outer cylinder is smaller at both end portions than in the central portion, so that the distance between the rear end of the rubber buttocks and the front end thereof is small. The difference in spring constant between the inner cylinder and the outer cylinder is larger than that in the conventional joint in which both the inner cylinder and the outer cylinder are substantially cylindrical.

Thus, in the state in which the difference in spring constant occurs, a lateral force in the centripetal direction acts on the turning outer wheel due to the inertia of the vehicle body during turning of the vehicle, and the outer cylinder 56 causes the inner cylinder 54 to move axially. When the rubber bush 58 is pressed by the force F in the inboard direction along 42, the reaction force of the rubber bush 58 against the force is higher at the rear end of the vehicle than at the front end of the vehicle. The front lower arm 26 has a rotational moment M directed toward the front of the vehicle around the center of the joint 34 at its inner end.
As a result, the angle at which the front lower arm pivots rearward around its inner end is reduced as compared with the conventional case, and the reduction amount of the caster trail on the turning outer wheel side is reduced. .

FIGS. 5 and 6 respectively show the joints at the inner ends of the front lower arms in the second and third embodiments of the double joint type suspension according to the present invention when the vehicle goes straight (a) and when it turns (b). It is an expanded plane sectional view shown. In these figures, the parts corresponding to the parts shown in FIG. 3 are designated by the same reference numerals as those shown in FIG.

In the second embodiment shown in FIG. 5, the outer cylinder 56 has a cylindrical shape extending along the axis 32 when viewed in a straight traveling state of the vehicle, while the inner cylinder has a cylindrical shape. Reference numeral 54 includes a central portion 54a having a small diameter and end portions 54b and 54c having large diameters. Each of the end portions 54b and 54c has a taper portion whose diameter gradually increases toward the outer end and a portion whose diameter is substantially constant, whereby an outer surface of the inner cylinder 54 and an inner surface of the outer cylinder 56 are formed. The distance between them is set smaller at both ends than at the center.

In the third embodiment shown in FIG. 6, both the inner cylinder 54 and the outer cylinder 56 are cylindrical, but rubber bushes 58 are formed on the inner peripheral surfaces of both ends of the outer cylinder. Rings 60a and 6 made of a material or a substantially rigid material having a spring constant much higher than that of the rubber constituting the
0b is fixed. Illustrated rings 60a and 60b
The inner diameter of the ring is set to be the smallest in the central portion in the longitudinal direction, so that these rings can be attached to the outer cylinder 56.
Functioning in the same manner as the radially inwardly curved ends of the outer cylinder of the first embodiment, the distance between the outer surface of the inner cylinder and the substantially inner surface of the outer cylinder is It is set to be smaller at both ends than at the center.

Therefore, also in these embodiments, when the vehicle turns, the reaction force of the rubber bush 58 of the joint 34 on the turning outer wheel side pivotally biases the front lower arm 26 around its inner end toward the front of the vehicle. As compared with the conventional case, the angle at which the front lower arm pivots rearward around the inner end of the front lower arm is reduced, so that the reduction amount of the caster trail on the turning outer wheel side is reduced.

Thus, according to each of the illustrated embodiments, since the reduction amount of the caster trail on the turning outer wheel side can be reduced, the steering wheel at the time of steering can be reduced as compared with the conventional double joint type suspension. It is possible to reduce the feeling of response and the deterioration of the returnability of the steering wheel, and the spring constant of the rubber bush 58 of the joint 34 provided at the inner end of the front lower arm 26 is not increased over its entire length. Since the vertical pivoting is not hindered, deterioration of durability of the rubber bush 58 and deterioration of riding comfort of the vehicle can be avoided.

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

For example, in the illustrated embodiment, the inner cylinder 54 is fixed to the vehicle body and the outer cylinder 56 is fixed to the inner end of the front lower arm, but the inner cylinder is fixed to the inner end of the front lower arm. May be fixed to the vehicle body. Further, for example, by combining the first or third embodiment and the second embodiment, both ends of both the outer cylinder and the inner cylinder may be curved inward in the radial direction to set a large diameter. . Further, rings similar to the rings 60a and 60b in the third embodiment may be fixed to the outer surfaces of both ends of the inner cylinder 54, and both the outer surfaces of both ends of the inner cylinder and the inner surfaces of both ends of the outer cylinder. May be fixed to.

Further, in the illustrated embodiment, the joint structure of the present invention is applied to the pivotal support portion at the inner end of the front lower arm, but the joint structure of the present invention is one of a pair of suspension arms in the lateral direction of the vehicle. It may be applied to the inner end of the suspension arm having a small inclination angle with respect to, for example, a structure in which the front lower arm is inclined rearward of the vehicle when viewed from the inner end toward the outer end, and the rear lower arm extends substantially in the lateral direction. In this case, the joint structure of the present invention may be applied to the inner end of the rear lower arm.

Further, although the above embodiment is configured as a double wishbone type suspension in which the upper arm is an A type arm, the suspension of the present invention is applied to the MacPherson strut type suspension and the application of the same applicant as the present applicant. The suspension may be configured as various other suspensions such as the suspension described in the specification of Japanese Patent Application No. 3-38760 and the drawings.

[0032]

As is apparent from the above description, according to the present invention, turning along with an increase in steering angle is achieved without substantially increasing the spring constant about the central axis of the joint at the inner end of one suspension arm. Since the amount of caster trail on the outer wheel side can be reduced, steering can be performed compared to the conventional double wishbone suspension without deteriorating the durability of the joint at the inner end of the suspension arm and the riding comfort of the vehicle. It is possible to reduce the feeling of response of the steering wheel and the deterioration of the returning characteristic of the steering wheel.

[Brief description of drawings]

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

FIG. 2 is an enlarged plan view showing a front lower arm and a rear lower arm of the first embodiment shown in FIG.

FIG. 3 is an enlarged plan sectional view showing the joint at the inner end of the front lower arm when the vehicle is straight ahead (a) and when the vehicle is turning (b).

FIG. 4 is a skeleton diagram showing movements of a front lower arm and a rear lower arm on a turning outer wheel side when viewed from above the vehicle.

FIG. 5 is an enlarged plan sectional view showing the joint at the inner end of the front lower arm of the second embodiment of the double joint type suspension according to the present invention when the vehicle is traveling straight (a) and turning (b).

FIG. 6 is an enlarged plan sectional view showing a joint at an inner end of a front lower arm of a third embodiment of a double joint type suspension according to the present invention when the vehicle is straight ahead (a) and when the vehicle is turning (b).

[Explanation of symbols]

 10 ... Carrier 12 ... Wheel 14 ... Upper Arm 24 ... Vehicle Body 26 ... Front Lower Arm 28 ... Rear Lower Arm 46 ... King Pin Shaft 54 ... Inner Cylinder 56 ... Outer Cylinder 58 ... Rubber Bushing

Claims (1)

[Claims] 1. A carrier that rotatably supports a wheel, and a pair of suspension arms that are pivotally attached to the carrier at an outer end and pivotally supported by a vehicle body at an inner end and are substantially separated from each other in a vehicle longitudinal direction. In the double joint type suspension for a steering wheel in which the axes of the pair of suspension arms intersect on the outboard side from the outer end when viewed from above the vehicle, at least one of the pair of suspension arms is The inner end has a joint including an inner cylinder and an outer cylinder arranged concentrically with respect to a central axis extending substantially in the vehicle front-rear direction, and a rubber bush interposed therebetween, and the inner cylinder and One of the outer cylinders is fixed to the vehicle body, the other of the inner cylinder and the outer cylinder is fixed to the inner end of the one suspension arm, and the distance between the outer surface of the inner cylinder and the inner surface of the outer cylinder is fixed. Steering wheel double-joint type suspension, wherein small At a both end portions than at the central portion along the central axis.