JPS6146338B2 - - 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, the tires are desired 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. In addition, by increasing this drag and improving the grip of the rear wheels, it is possible to strengthen the tendency for understeer and improve the stability of the car. Furthermore, when you press and release the accelerator during cornering, 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). In addition, when you step on the brakes or apply engine braking, the rubber bushings installed to improve ride comfort are located inside the tire's ground contact point, so the braking force causes toe-out. , steering stability deteriorates. The softer the rubber bushings, the better the ride comfort, 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 naturally acts as a lateral force when there is a crosswind, but depending on the car, even if there is no crosswind, it acts on the tires as a disturbance from various directions. Even in the face of 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 tire as either the aforementioned lateral force or braking force. 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 in the past that have a toe-in effect against lateral force during cornering, but all of them are somewhat complex in structure. For example, the one described in Japanese Patent Publication No. 52-37649 uses three rubber bushings with different hardness;
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. Furthermore, this type 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 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, boot force, engine braking force, or driving force, regardless of whether the vehicle is turning or going straight, resulting in comfortable handling. 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 part is swingably supported on the vehicle body via one ball joint and two rubber bushes. The stabilizer has a center of rotation in the left-right direction of the vehicle body and is rotatably supported by the vehicle body via a control link, and is connected to a wheel support member. It is placed in the fourth quadrant of the reference horizontal-vertical coordinates, at least one of the rubber bushes is placed forward of the wheel center, and the plane that includes these two rubber bushes and the ball joint is the vertical plane that includes the wheel center axis. At the height of the wheel center, the wheel is placed inward from the left and right center of the vehicle body, and on the ground, is placed outside the vehicle body, and the axis of the rubber bushing is rotated clockwise around the ball joint of the wheel support member inwardly in front of the wheel center. The swinging member is installed so that the rotation locus of the wheel support member moves inward in the left-right direction of the vehicle body when bumping, and the end of the stabilizer is positioned behind the ball joint. The swing member is also connected to a wheel support member above the swing center of the swing member. In the present invention, the swinging member refers to a swinging support member on the vehicle body side that is partially supported swingably on the vehicle body, such as a semi-trailing arm of a semi-trailing type rear suspension, or a strut-type rear suspension. It is a general term for various support members attached to the vehicle body, such as the strut of a pension, the upper and lower arms of a suspension type rear suspension, and the tube of a rear suspension type. It is not limited to things. 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 link is a link member that is connected between a bracket supported at the center portion of the stabilizer extending in the left-right direction of the vehicle body and a bracket on the vehicle body side in order to support the stabilizer on the vehicle body while allowing the stabilizer to be moved to some extent. be. In addition, 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 centered on the wheel center, and each of the first to fourth 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 displaces the wheel support member in the toe-in direction. This is because it works like this. 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 due to 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 conceptual diagram showing the basic structure and function of an embodiment of the rear suspension of the present invention, and shows the right rear wheel seen from the left (inside) rear in the center.
Projections from the rear and above are shown on the left, right, and bottom, respectively. The ball joint 11 is disposed on the lower side behind the wheel center W (that is, in the fourth quadrant of the coordinates), and is located between the two rubber bushes 12, 1.
3 is located forward of the wheel center W (ie, in the second or third quadrant of the coordinates). Also, these two rubber bushes 1
The plane P that includes the three parts 2, 13 and the ball joint 11 is the height of the wheel center in the vertical plane that includes the wheel center axis C (its projection is shown on the left in Figure 1).
In CL, it is located inside the vehicle body from the center W of the wheel left and right, and in Grand GL, it is located outside the vehicle body. Furthermore, the shafts 12 of the rubber bushes 12 and 13
a and 13a are arranged in such a direction as to guide the wheel hub 10 inwardly in front of the wheel center W when the wheel hub 10 rotates clockwise around the ball joint, that is, in a direction that causes the tire 14 to be toe-in. That is, the front rubber bushing 12 is oriented rearward inward, and the rear rubber bushing 13 is oriented rearward outward. This direction may be reversed depending on the position of the rubber bushes 12, 13. That is, for example, when the front rubber bushing 12 is arranged horizontally or diagonally toward the bottom of the third quadrant with the front high and the rear low, the axis 12a is directed forward inward rather than backward inward. This is to displace the clockwise rotation of the wheel hub 10 around the ball joint 11 in the toe-in direction in either case. Also, the arm 15 is rearwardly moved from the wheel hub 10.
extends, and the front end 16a of the front bent portion 16A of the stabilizer 16 is connected to the rear end 15a of the arm 15. Center part 16B of stabilizer 16
A control link 17 extends in the left-right direction of the vehicle body and has one end 17a connected to a vehicle body side bracket 18.
It is supported by the other end 17a via a bracket 19, and is rotatably supported in the left-right direction of the vehicle body. Therefore, at the time of a bump, the end portion 16a of the stabilizer 16 can move in the vertical direction along the vertical trajectory A in the projection view on the left side of FIG. On the other hand, the wheel hub 10 is supported by a swing member that is a support member on the vehicle body side, such as a semi-trailing arm that is partially swingably supported by the vehicle body.
This swinging member is attached so that the rotation locus of the wheel hub moves inward in the left-right direction of the vehicle body (as shown by locus B on the left in FIG. 1) when the vehicle bumps. Further, a connecting portion between the end portion 16a of the stabilizer and the rear end 15a of the arm 15 of the wheel hub 10 is located behind the ball joint 11 and above the center of swing of the swing member. Hereinafter, the toe-in effect due to external force will be explained in detail in the case of this embodiment with reference to FIG.
In FIG. 1, the vertical imaginary axis passing through the ball joint 11 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 the lateral force S of the tire acts during cornering, etc., a rotational moment is generated around the L axis in a counterclockwise direction when viewed from above, and the rubber bushes 12, 13
Due to the elasticity of the wheel hub 10, the wheel hub 10 is displaced around the ball joint 11 in the toe-in direction. At this time, if the elasticity of the front rubber bushing 12 on the inside in the right angle direction and the elasticity of the rear rubber bushing 13 on the outside in the right angle direction are increased, an even greater toe-in effect can be obtained. At the same time, due to a one-sided bump during cornering, the wheel hub 10 or the end 15a of the arm 15 may
The stabilizer 16 attempts to move upward and inward along a trajectory B, but at this time, it receives an outward stabilizing reaction force HF due to an upward trajectory A of the end 16a of the stabilizer 16. Therefore, the rear portion of the wheel hub 10 is displaced outward, and thus displaced in the toe-in direction. Also, at this time, a vertical component VF of the stabilizing reaction force from the stabilizer 16 acts downward on the rear end 15a of the arm 15 of the wheel hub 10.
Due to the vertical component VF of this stabilizer reaction force, wheel 1
0 rotates around the ball joint 11 in a clockwise direction (as viewed from the left). This clockwise rotation causes the front of the wheel hub 10 to be displaced inwardly and the rear to be outwardly due to the orientation of the axes of the rubber bushes 12 and 13, as described above, and as a result, the wheel hub 10 is displaced in the toe-in direction. In this way, during cornering, both the lateral force S and the stabilizer reaction forces HF and VF 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 10 moves around the ball joint 11 ( (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 trying to rotate the wheel hub 10 counterclockwise (as viewed from the left side) around the M axis. As a result, the wheel hub 10 tends to be displaced in the direction of toe-out. 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 it in this way, By providing a stopper on the front side, toe-in can be ensured. When the engine brake E acts on the wheel center W from front to back, the tire tries to rotate clockwise around the M axis. The clockwise rotation around the M-axis displaces the wheel hub 10 in the toe-in direction depending on the orientation of the rubber bushes 12 and 13, as in the case of the vertical component VF of the stabilizer reaction force.
However, since the wheel center W is located outside the plane P including the ball joint 11 and the rubber bushes 12 and 13 at this time, the engine braking force E acts in the toe-out direction around the L axis. However, 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. 12), a toe-in effect is ultimately obtained. 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 10 has a toe-in tendency around the L axis, rotation around the M axis, and the rubber bush 12. As a result of the overall effect of the toe-out tendency due to the direction of the number 13, the toe-out tends to occur. Therefore, by providing a stopper in front of either of the rubber bushes 12, 13 to restrict rotational displacement in the counterclockwise direction around the M-axis, the movement of the rubber bushing and the ball joint 11 with the stopper in front can be ensured around the L-axis. The wheel hub 10 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, there is an effect of toe-in the tire when any of the four external forces of lateral force S, braking force B, engine braking force E, and driving force K is applied, and it also has the effect of toeing the tire on one side due to cornering etc. Even when bumping, a rear suspension that has the effect of toe-in the tire on the bumped side by using the stabilizing reaction forces VF and HF can be obtained. 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, examples in which the present invention is applied to a semi-trailing type rear suspension will be described in Sections 2A and 2.
This will be explained with reference to FIGS. B, 2C, 3A, 3B, 4A, 4B, and 5. Figure 2A is a view of the right rear wheel viewed from above, Figure 2B is a side view of the right rear wheel viewed from the outside (however, the tires are shown with imaginary lines), and Figure 2C is a view of Figure 2A viewed from the left. It is. Two arms 20A, 2 extending forward in a bifurcated shape
The front end of each arm 20A, 20B of the semi-trailing arm 20 having 0B is attached to a shaft support 21 on the vehicle body.
a, 21b, and a wheel hub 22 is supported by a ball joint 23, a first rubber bush 24 and a second rubber bush on the outside of the rear main body 20C.
It is supported via a rubber bushing 25. The wheel hub 22 also has an arm 22 extending rearward.
A is integrally provided, and the rear end of the rear bending portion 27A of the stabilizer 27 supported by the vehicle body via the control link 26 is connected to the rear end of the arm 22A. The cross section of the front rubber bush 24 is shown in No. 3A, 3.
Shown in Figure B. As is clear from these cross-sectional views, the rubber bush 24 is integrally fixed to the wheel hub 22 so as to allow the wheel hub 22 to be largely displaced inward of the vehicle body, but not vice versa, that is, to prevent outward displacement. Rubber 24a between the arm portion 22a and the shaft portion 20d that is integrally fixed to the main body 20c of the Yami trailing arm 20.
is made softer on the outside of the car body and harder on the inside of the car body. That is, a hard rubber or a stopper 24a' is inserted between the shaft portion 20d and the inside of the arm 22a to prevent the arm 22a from moving outward. The cross section of the rear rubber bush 25 is shown in No. 4A, 4.
Shown in Figure B. As clearly shown in FIG. 4A, the front flange 20e of a pair of maranges fixed to the main body 20c side of the semi-trailing arm
A stopper 25a is provided between the arm 22b and the arm 22b on the wheel hub 22 side to prevent forward displacement. FIG. 5 is a cross-sectional view showing details of the ball joint 23, in which the arm 22B integrally provided on the wheel hub 22 is connected to the semi-trailing arm 20.
It is rotatably supported on a flange 20f on the main body 20c side and a shaft 20g. This shaft 20g has a spherical surface and forms a ball of a ball joint. 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. 1, 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 conceptual diagram showing the main parts of the rear suspension of the present invention in detail, showing a perspective view of the right rear wheel viewed from the rear left side and a three-directional projection view thereof, and Fig. 2A is a semi-sectional view showing the rear suspension of the present invention. Fig. 2B is a partially cutaway top view of the right rear wheel showing an example of application to a trailing type rear suspension; Fig. 2B is a side view of the example shown in Fig. 2A, looking through the tire from the right outside; Fig. 2C Figure 2A viewed from the left, Figure 3A is the front rubber bushing 2.
4, FIG. 3B is a central cross-sectional view, and FIG. 4A is a B-- of the rear rubber bushing 25.
B line sectional view, Figure 4B is the central cross sectional view, Figure 5
The figure is a sectional view of the ball joint 23. 10... Wheel hub, 11, 23... Ball joint, 12, 13, 24, 25... Rubber bush, 14... Tire, 15, 22A... Arm, 1
6, 27... Stabilizer, 17, 26... Control link, 20... Semi-trailing arm.

Claims (1)

[Claims] 1. A rocking member whose part is swingably supported on the vehicle body;
A wheel support member that rotatably supports the rear wheel is supported at three points on this swing member via a ball joint and two rubber bushes, and a wheel support member has a rotation center in the left-right direction of the vehicle body and is supported at three points via a control link. The stabilizer is rotatably supported on the vehicle body, 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 body, and at least one of the two rubber bushes is attached to the wheel. Located in front of the center, these two rubber bushes and three ball joints
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 swinging member is oriented 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 swinging member is arranged so that the rotation locus of the wheel support member moves inward in the left-right direction of the vehicle body when bumping. A rear suspension for an automobile, wherein the end portion of the stabilizer is connected to a wheel support member behind the ball joint and above the center of swing of the swing member.