JPS6144688B2 - - 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. In other words, a rear suspension that always has a tendency to toe-in will always achieve stable cornering. In addition, the tendency of rear suspension toe-in is not limited only when cornering.
This is also desirable from the viewpoint 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 the car receives while driving 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 end up acting on the tires as one of the aforementioned lateral forces, braking 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 in front of the tire's grounding point. The force from 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. 52-37649 uses three rubber bushings and the hardness of the bushings is changed, and the one described in West German Patent Publication No. 2158931 or West German Patent Publication No. 2355954 is The wheel hub is supported via a vertical shaft and a spring, making the structure complex.
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 stabilizer control rod is connected to the support member, and in particular, the ball joint is located in the fourth quadrant of the horizontal-vertical coordinates based on the wheel center when viewed from the left side of the vehicle, and at least one of the rubber bushes is located from the wheel center. The plane containing these two rubber bushes and the ball joint is located at the height of the wheel center on a vertical plane that includes the wheel center axis, inside the vehicle body from the left and right center of the wheel, and outside the vehicle body on the ground. The shaft of the rubber bushing is arranged in such a direction as to guide clockwise rotation of the wheel support member around the ball joint inwardly in front of the wheel center when viewed from the left side of the vehicle body, and the control rod is moved downwardly and outwardly. It is characterized in that it is arranged so as to be inclined in the direction of the ball joint, and is connected to the wheel support member at the rear 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. Further, the term "wheel support member" is a general term for members such as wheel hubs that rotatably support tires, and 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 causes the wheel support member to rotate in the toe-in direction around the ball joint, and the stabilizing reaction force due to one side bump during cornering is transmitted to the wheel support member via the control rod. This is because it acts to displace the toe-in direction. 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 rotatably supported on 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. The wheel hub 18 is integrally provided with an arm 22 extending rearward, and a control rod 24 whose one end is connected to the end 23a of the stabilizer 23 is connected to the rear end 22a of this arm 22. The stabilizer reaction force is transmitted to the arm 22. The ball joint 21 is arranged in the fourth quadrant of the horizontal-vertical coordinates based on the wheel center when viewed from the left side of the unit, and one of the two rubber bushes 19, 20, 19, is arranged forward of the wheel center. Further, the control rod 24 is arranged to be inclined downwardly and outwardly, and is connected to an arm 22 extending rearward from the wheel hub 18 to transmit the stabilizing reaction force outward 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.
The lower side of the rear (i.e. the fourth quadrant of the above coordinates)
One of the two rubber bushes 19, 20 is located forward of the wheel center W (ie, in the second or third quadrant of the coordinates). Also, these two rubber bushes 19,
20 and the ball joint 21 is a vertical plane containing the wheel center axis C (its projection is
(shown on the left), the height CL of the center of the wheel
On the ground GL, it is placed inside the car body from the wheel left and right center W, and on the ground GL it is placed outside the car body. 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 clockwise around the ball joint, that is, in a direction to toe-in the tire 12. That is, the front rubber bushing 19 is oriented rearward inward, and the rear rubber bushing 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 toward the bottom of the third quadrant with the front high and the rear low, the axis 19a is directed forward inward rather than backward inward. . This is for the purpose of displacing the clockwise rotation of the wheel hub 18 around the ball joint 21 in the toe-in direction in either case. The toe-in effect due to the outside will be explained in detail in the case of this embodiment with reference to FIG. 2 below.
In FIG. 2, the vertical imaginary axis passing through the ball joint 21 is L, the imaginary axis in the width direction of the vehicle body is M, and the imaginary axis in the longitudinal direction is N. 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, 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 obliquely upward on the rear end of the arm 22 of the wheel hub 18 via the control rod 24. The vertical component VF of the stabilizer reaction force F causes the wheel hub 18 to rotate clockwise (as viewed from the left) around the ball joint 21, and the rear is displaced outward due to the horizontal component HF of the stabilizer reaction force F. . This clockwise rotation causes the wheel hub 18 to rotate through the rubber bush 1.
Depending on the direction of the axes 9 and 20, the front is displaced inward and the rear is displaced outward, resulting in displacement of the wheel hub 18 in the toe-in direction. Further, due to the outward action of the horizontal component force HF, the wheel hub 18 similarly 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. When the brake force B acts on the grounding point G from front to back, the wheel hub 18 moves around the ball joint 21 ( (around the L axis) in a counterclockwise direction when viewed from above, that is, in a toe-in direction T. On the other hand, this braking force B has the effect of attempting to rotate the wheel hub 18 counterclockwise (as viewed from the left side) around the M axis. As a result, the wheel hub 18 tends to be displaced in the toe-out direction. At this time, if the action of the braking force B around the L axis is larger, there is no problem because a toe-in effect can be obtained after all, but since it is not always possible to design in this way, it is necessary to By providing a stopper on the front side, toe-in can be ensured. When the engine braking force E acts on the wheel center W from front to back, the tire tends to rotate clockwise 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. However, at this time, since the wheel center W is located outside the plane P including the ball joint 21 and the rubber bushes 19 and 20, the engine braking force E acts in the toe-out direction around the L axis. but,
In this case, the toe-in effect due to rotation around the M-axis is greater than the toe-out effect around the L-axis (rubber bushes 19 and 20 are easier to deform in the axial direction of the bushes than in the thickness direction, and the ball of the wheel center W (This is due to the fact that the offset from the joint 21 is larger in the vertical direction than in the lateral direction.) Therefore, a toe-in effect is obtained after all. When the driving force K acts on the wheel center W from the rear to the front, this is a force in the opposite direction to the engine braking force E, so the wheel hub 18 has a toe-in tendency around the L axis, rotation around the M axis, and the rubber bush 19. As a result of the overall effect of the toe-out tendency due to the orientation of 20, the toe-out tendency occurs. Therefore, by providing a stopper in front of either of the rubber bushes 19, 20 to restrict rotational displacement in the counterclockwise direction about the M-axis, the rotational displacement of the rubber bushing and ball joint 21 with the stopper provided in front can be ensured around the L-axis. The wheel hub 18 can be displaced in the toe-in direction around the line connecting the . 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 even when bumping by the vertical component VF and horizontal component HF of the stabilizing reaction force F. 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, an example in which the present invention is applied to a semi-trailing type rear suspension will be described in Sections 3A and 3.
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 tires are shown with imaginary lines);
Figure C is a view of Figure 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 rearward.
A is integrally provided, and the lower end of a control rod 36 is connected to the rear end of this arm 32A. connected to the front end. 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 clockwise (as seen from the left, that is, in the third quadrant) due to the stabilizer reaction force.
It is arranged upwardly and inwardly so as to guide the rotation inwardly (when viewed from the opposite direction to that in Figure B). The actions of the four types of external forces and the vertical and horizontal components of the stabilizing reaction force in this embodiment are exactly the same as in the embodiment shown in FIG. 2 described above, and are clear from the figure, so a description thereof will be omitted. In other words, the toe-in of the tire can be changed by any of these forces, and the desired effect can be achieved.

[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 to rotatably support the wheel, and a stabilizer control rod that transmits stabilizer reaction force to this wheel support member. The stabilizer comprises connected stabilizers, the ball joint is located in the fourth quadrant of the horizontal-vertical coordinates based on the wheel center when viewed from the left side of the vehicle, and at least one of the two rubber bushes is located forward of the wheel center; These two rubber bushes and ball joint 3
In a vertical plane including the wheel center axis, the surface including the rubber bushing is located inward of the vehicle body from the left and right center of the wheel at the height of the wheel center, and outside the vehicle body on the ground, and the shaft of the rubber bush is located at the ball joint of the wheel support member. The control rod is arranged so as to guide the clockwise rotation seen from the left side of the vehicle body inwardly in front of the wheel center, and the control rod is arranged to be inclined downwardly and outwardly, and the control rod is arranged so as to guide the clockwise rotation seen from the left side of the vehicle body inwardly in front of the wheel center. A rear suspension for an automobile, characterized in that the rear suspension is connected to a support member.