JPS6146335B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a rear suspension for an automobile, and more particularly to a novel rear suspension with excellent toe-in effect. BACKGROUND ART In the rear suspension of an automobile, in order to improve steering stability, riding comfort, etc., it is desired to have a rear suspension that allows tires to be toe-in during driving, especially when cornering. In other words, as is well known, when cornering, the centrifugal force applied to the vehicle body acts on the suspension as a lateral force.
In order to increase the turning limit G, it is desirable for tires to counteract this lateral force with a large resistance force. This drag can be increased by toe-in the tire and increase the slip angle. Also, if you increase this drag and improve the grip of the rear wheels, you can strengthen the tendency to understeer,
It can improve the stability of the car. moreover,
When cornering, when you press and release the accelerator, driving force and braking force are applied to the tires, but when you release the accelerator, the tires tend to suddenly toe out, and when you press the accelerator, they tend to toe in. This causes the tires to toe in or toe out during cornering, resulting in a decrease in steering stability (hereinafter referred to as steering stability). Also, when you step on the brakes or apply engine braking, the rubber bushings installed to improve riding comfort are located inside the tire's ground contact point, so the braking force can cause toe-out. This results in poor handling. The softer the rubber bushings, the better the ride quality, so the more comfortable a car is, the worse it will be in handling. Therefore, a rear suspension that provides toe-in even when braking force is applied by the brake or engine brake is desired. That is, according to the suspension, which always tends to toe-in.
This ensures stable cornering at all times. Furthermore, the toe-in tendency of the rear suspension is desirable not only when cornering, but also from the standpoint of high-speed straight-line performance, which is particularly required for sports cars. That is, the road surface is actually not completely flat and always has irregularities of various sizes, but these irregularities cause disturbances to the tires from various directions. In addition, the wind that a moving car receives also acts as a lateral force when there is a crosswind, but even when there is no crosswind, the wind acts on the car's tires as a disturbance from all directions. Even in response to these disturbances, if the rear suspension always acts to toe-in the rear wheels, the car will tend to understeer and become stable. Regardless of the cause, these disturbances ultimately act on the tires as one of the aforementioned lateral forces, control forces, and driving forces. Therefore, the rear suspension is desired to have the effect of toe-in the tires against all of the lateral force, braking force (there are two types: braking and engine braking), and driving force. To explain these external forces in detail, the lateral force represented by the thrust load during cornering is the force that acts from the outside to the inside of the tire's grounding point, and the braking force when applying the brakes is the force that acts from the front to the tire's grounding point. force that acts backwards,
The force caused by the engine brake is the force that acts on the wheel center of the tire from front to back, and the driving force is the force that acts on the wheel center from the back to the front. This can be expressed in a table as shown below.

[Table] Various types of rear suspensions have been known that have a toe-in effect against lateral force during cornering, but all of them are structurally somewhat complex. For example, the one described in Japanese Patent Publication No. 52-3769 uses three rubber bushings and the hardness of the bushings is changed.
The wheel hub described in No. 2158931 or No. 2355954 has a wheel hub supported via a vertical shaft and a spring, and has a complicated structure. Further, this kind of rear suspension that is known in the past does not achieve toe-in effects against all of the above four types of external forces, but is mainly effective only against lateral forces. SUMMARY OF THE INVENTION An object of the present invention is to provide a novel rear suspension that has an extremely simple structure and can effectively toe-in the rear wheels against external forces, especially during cornering. Furthermore, the present invention has an extremely simple structure that enables toe-in of the rear wheels in response to any external force such as lateral force, braking force, engine braking force, or driving force, regardless of whether the vehicle is turning or going straight. The aim is to provide a completely new type of rear suspension that makes it possible to create highly safe cars. In the rear suspension of the present invention, a rear wheel support member is connected to a swinging member whose one end is swingably supported on the vehicle body through one ball joint and two rubber bushes, and The control rod of the stabilizer is connected to the support member. In particular, the ball joint is placed above the wheel center, and the shaft of the rubber bushing controls the counterclockwise rotation of the wheel support member around the ball joint at the wheel center. The control rod is arranged at the front so as to be guided inward, and the control rod is arranged so as to be inclined downward and inward, and is connected to the wheel support member at the front of the ball joint. . In the present invention, the swinging member refers to a swinging support member on the vehicle body side whose one end is swingably supported on the vehicle body, such as a semi-trailing arm of a semi-trailing type rear suspension, or a strut-type rear suspension. This is a general term for various support members attached to the vehicle body, such as the struts of the rear suspension, the upper and lower arms of the suspension type rear suspension, and the tube of the rear suspension of the rear suspension type. It is not limited to the format. In addition, wheel members are a general term for members such as wheel hubs that rotatably support tires.
It is not limited to a specific wheel hub. In addition, the control rod is a link member connected between the end of the stabilizer and a part of the wheel support member in order to transmit the stabilization reaction force of the stabilizer to the wheel support member. It transmits power. Furthermore, the quadrant defined in the present invention is a quadrant in rectangular coordinates when looking at the rear wheel from the left side of the vehicle body and imagining horizontal and vertical orthogonal axes with the wheel center as the center. All quadrants include the axes at both ends that limit the quadrant (for example, in the first quadrant, the right half of the horizontal axis and the upper half of the vertical axis). In the present invention, the direction of rotation of the wheel support member is also expressed as clockwise, counterclockwise, etc. when viewed from the left side of the vehicle body. According to the rear suspension of the present invention, when a lateral force is applied during cornering, it is possible to effectively toe-in the tire. Due to the arrangement of the ball joint and rubber bush, lateral force rotates the wheel joint in the toe-in direction, and the stabilizing reaction force due to one side bump during cornering moves the wheel support member in the toe-in direction via the control rod. This is because it acts to cause displacement. Further, according to the present invention, it is possible to effectively toe-in the tire when any of the four types of external forces are applied.
This is also an effect of the arrangement of the ball joint and rubber bush. Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing an example in which the present invention is applied to a strut type twin link suspension. A bracket 13 for supporting a wheel hub 18 of a tire 12 is connected to the rear end of a trailing link 11 extending rearward from the end of the vehicle frame 10. This bracket 13 is connected to the lower end of the shock absorber 25 and to the tips of a pair of lateral links 14. Further, a drive shaft 17 extending laterally from a differential case 16 fixed to the cross member 15 is connected to the wheel hub 18 . A wheel hub 18 is mounted on the bracket 13 via two rubber bushes 19 and 20 and a ball joint 21 so as to be rotatably displaceable around the ball joint 21. An arm 22 extending forward is integrally provided on the wheel hub 18, and a control rod 24 whose one end is connected to an end 23a of a stabilizer 23 is connected to a front end 22a of this arm 22. The reaction force is transmitted to the arm 22. The ball joint 21 is located above the wheel center, and at least one of the two rubber bushes 19, 20 is located below the wheel center. Further, the control rod 24 is arranged to be inclined downwardly and inwardly, and is connected to an arm 22 extending forward from the wheel hub 18 to transmit the stabilizing reaction force downwardly and inwardly to the wheel hub 18. The main parts of FIG. 1 are shown in detail in FIG. 2. FIG. 1 is a view of the left rear wheel viewed from the left front, and FIG. 2 is a view of the right rear wheel viewed from the left (inside) rear, and corresponding members are designated by the same reference numerals. As clearly shown in Figure 2, the ball joint 21 is located at the wheel center W.
One of the two rubber bushes 19, 20, 19, is located lower than the wheel center W (ie, in the third or fourth quadrant of the coordinates). Furthermore, the shaft 19 of the rubber bushes 19, 20
a and 20a are arranged in such a direction as to guide the wheel hub 18 inwardly in front of the wheel center W when the wheel hub 18 rotates counterclockwise around the ball joint, that is, in a direction that causes the tire 12 to be toe-in. . That is, the front rubber bush 19 is oriented rearward inward, and the rear rubber bush 20 is oriented rearward outward. This direction may be reversed depending on the position of the rubber bushes 19, 20. That is, for example, when the front rubber bush 19 is arranged horizontally or diagonally in the upper part of the second quadrant with the rear high and the front low, the axis 19a is directed forward inward rather than backward inward. . This is for the purpose of displacing the counterclockwise rotation of the wheel hub 18 around the ball joint 21 in the toe-in direction in either case. Hereinafter, the toe-in effect due to external force will be explained in detail in this embodiment with reference to FIG.
In FIG. 2, the vertical imaginary axis passing through the ball joint 21 is L, and the imaginary axis in the width direction of the vehicle body is M. The lateral force S acts on the tire grounding point G from outside to the inside, the braking force B acts on the grounding point G from the front to the rear, and the engine braking force E acts on the wheel center W from the front to the rear. The driving force K acts on the wheel center W from the rear to the front. When a lateral force S acts on the tire during cornering, etc., a rotational moment is generated around the L axis in a counterclockwise direction when viewed from above, and the rubber bushes 19, 20
Due to the elasticity of the wheel hub 18, the wheel hub 18 is displaced around the ball joint 21 in the toe-in direction. Incidentally, at this time, if the elasticity of the front rubber bushing 19 is made larger than the elasticity of the rear rubber bushing 20, an even greater toe-in effect can be obtained. At the same time, a stabilizing reaction force F from the stabilizer 23 due to a bump on one side during cornering acts diagonally downward and inward at the front end of the arm 22 of the wheel hub 18 via the control rod 24. The vertical component VF of this stabilizer reaction force F causes the wheel hub 1 to
8 rotates counterclockwise (as viewed from the left) around the ball joint 21, and its front is displaced inward by the horizontal component HF of the stabilizer reaction force F. This counterclockwise rotation causes the front of the wheel hub 18 to be displaced inwardly and rearward due to the orientation of the axes of the rubber bushes 19 and 20, resulting in the wheel hub 18 being displaced in the toe-in direction. In addition, the horizontal component force HF
Similarly, the inward action of the wheel hub 18
receives a force in the toe-in direction and is effectively displaced in the toe-in direction. In this way, during cornering, both the lateral force S and the stabilizing reaction force F produce a toe-in effect, making it possible to effectively toe-in the tire. Next, brake force B, engine brake force E,
The toe-in effect due to the driving force K will be explained. Brake force B or engine brake force E
acts on the ground point G or the wheel center W from front to back, respectively, and the tire tries to rotate counterclockwise around the M axis. The clockwise rotation around the M-axis displaces the wheel hub 18 in the toe-in direction depending on the orientation of the rubber bushes 19 and 20, as in the case of the stabilizer reaction force F described above. When the driving force K acts on the wheel center W from the rear to the front, since this is a force in the opposite direction to the engine braking force E, the wheel hub 18 tends to toe out by rotating clockwise around the M axis. Therefore, this toe-out can be prevented by providing a stopper in front of either one of the rubber bushes 19, 20 to restrict clockwise rotational displacement around the M-axis. Furthermore, if the surface including the ball joint 21 and the rubber bushes 19 and 20 is located inward of the vehicle body from the wheel center W at the height CL of the wheel center W, the driving force K is transferred to the rubber bush with the stopper provided in front. It acts to displace the wheel hub 18 in the toe-in direction around the line connecting the ball joint 21 and the ball joint 21. As is clear from the detailed description of the above embodiments,
According to the present invention, it is possible to toe-in the tire when any of the four external forces, lateral force S, brake force B, engine brake force E, and driving force K, is applied, and also toe-in the tire on one side due to cornering etc. It is possible to obtain a rear suspension that has the effect of toe-in the tire on the bumped side by the stabilizing reaction force F even when bumping. Therefore, it is possible to realize a vehicle that is constantly stabilized during driving such as cornering, and that has improved maneuverability without impairing ride comfort. Further, this toe-in effect is advantageous in realizing a sports car with excellent straight-line performance at high speed, so the rear suspension according to the present invention has extremely high practical value. Next, the present invention is applied to a semi-trailing type rear suspension.
This will be explained with reference to figures B and 3C. Figure 3A is a view of the right rear wheel viewed from above, Figure 3B is a side view of it viewed from the right outside (however, the tire is shown with imaginary lines) Figure 3C
The figure is a view of FIG. 3A viewed from the left. Two arms 30A, 3 extending forward in a bifurcated shape
The front end of each arm 30A, 30B of the semi-trailing arm 30 having 0B is attached to a shaft support 31 on the vehicle body.
A and 31B, and the wheel hub 32 is supported by the ball joint 33, the first rubber bush 34, and the second rubber bush 34 on the outside of the rear main body 30C.
It is supported via a rubber bushing 35. The wheel hub 32 also has an arm 32 extending forward.
The lower end of a control rod 36 is connected to the front end of this arm 32A, and the upper end of this control rod 36 is connected to the front end of a forward bent portion 38A of a stabilizer 38 supported by a bracket 37 on the vehicle body. connected to. In this configuration, except for the arrangement of the front rubber bushing or second rubber bushing 35, all other members are the same as the embodiment shown in FIG.
The second rubber bush 35 is the first rubber bush 3.
4 and is located in the third quadrant (the definition of the quadrant is the same as above), and the wheel hub 32 is moved counterclockwise by the stabilizer reaction force (as viewed from the left, that is, in the opposite direction to that in FIG. 3B). It is arranged downwardly and inwardly so as to guide the rotation inwardly. The effects on the four types of external forces and stabilizing reaction forces in this embodiment are exactly the same as those in the embodiment shown in FIG. 2, and are clear from the figure, so a description thereof will be omitted. That is, any of these forces can change the toe-in of the tire and achieve the desired effect.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example in which the present invention is applied to a strut type twin link suspension;
Fig. 2 is a principle diagram showing the main parts in detail, and shows a perspective view of the right rear wheel seen from the left rear and its three-way projection view, and Fig. 3A shows the present invention as a semi-trailing type rear suspension. FIG. 3B is a partially cutaway top view of the right rear wheel showing an example of application to a tire. FIG. 3B is a side view of the example shown in FIG.
Figure C is a view of Figure 3A viewed from the left. 12... Tire, 14... Lateral link, 1
8, 32...Wheel hub, 19, 20, 34,
35...Rubber bush, 21,33...Ball joint, 22,32A...Arm, 23,3
8... Stabilizer, 24, 36... Control rod, 30... Semi-trailing arm.

Claims (1)

[Claims] 1. A swinging member whose one end is swingably supported on a vehicle body;
A wheel support member is supported at three points on this swinging member via a ball joint and two rubber bushes, and rotatably supports the wheel, and a stabilizer control rod that transmits stabilizer reaction force is connected to this wheel support member. The ball joint is arranged above the wheel center, and the shaft of the rubber bushing rotates the wheel support member in a counterclockwise direction when viewed from the left side of the vehicle body around the ball joint. It is arranged in such a way as to guide you in the direction.
A rear suspension for an automobile, wherein the control rod is arranged to be inclined downwardly and inwardly, and is connected to a wheel support member in front of the ball joint.