JPH0433643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to improvements in rear suspensions for automobiles, particularly independent suspension rear suspensions.

(Prior Art) In general, an independent rear suspension of an automobile is equipped with a trailing arm whose front end is attached to the vehicle body in at least two locations so as to be able to swing vertically, and the rear end of the trailing arm that extends toward the rear of the vehicle body. The rear wheel is rotatably supported at the end, but with this configuration,
When a lateral force is applied from the outside to the rear wheel on the opposite side to the turning direction during cornering, a problem arises in that the wheel behaves in a so-called toe-out direction, impairing turning performance. Conventionally, to solve this problem, an assist link is installed between the rear end of the trailing arm and the vehicle body, and this link supports the lateral force that acts on the rear wheel during cornering, thereby causing the toe-out direction. efforts are being made to prevent this. Furthermore, according to Japanese Patent Application Laid-Open No. 58-12811, by locating the center of behavior of the rear wheel in the horizontal plane due to lateral force behind the axis of the wheel, the wheel is caused to behave in the toe-in direction during cornering. An invention is disclosed. According to these, the behavior of the rear wheel in the horizontal plane during cornering is improved, and turning performance is improved.

However, in independent suspension type rear suspensions, in addition to the problem of the behavior of the rear wheel in the horizontal plane as described above, there is the following problem regarding changes in the camber angle during pumping and rebounding. In other words, when the trailing arm swings up and down due to the relative vertical movement of the vehicle body and wheels, the swing center axis (semi-trailing axis) of the arm is generally tilted rearward from the outside to the inside of the vehicle body. As a result, during a bump (when the wheel moves relatively upward), the camber angle changes in the negative camber direction, that is, the lower part of the wheel moves outward and the upper part moves inward, and during rebound. (When the wheel moves relatively downward), it will change in the direction of positive camber, but the direction and amount of change in camber angle in response to such bumps and rebounds will be in the direction of the semi-trailing axis. Therefore, it is determined uniquely. Therefore, driving performance can be freely adjusted by adjusting the camber angle, for example, by reducing the amount of change in the camber angle to improve straight-line stability, or by increasing the negative camber when bumps occur during cornering to improve turning performance. It becomes impossible to set.

In contrast, US Pat. No. 3,333,654 and the drawings disclose a trailing suspension that includes a link that corrects the amount of change in camber angle. However, this conventional technology
Since the driveshaft is configured to restrict the lateral displacement of the wheels, the tilt of the trailing arm's center axis of oscillation is greatly tilted toward the longitudinal direction of the vehicle body, resulting in changes in tread as the wheels move up and down. becomes too large, which causes problems such as deterioration of straight-line stability and easy tire wear. Furthermore, the structure of the joint portion of the drive shaft becomes complicated due to the need to absorb the lateral force acting on the rear wheel, which increases the cost and makes it difficult to use a commonly used constant velocity joint.

(Objective of the Invention) The present invention addresses the above-mentioned problems of independent rear suspensions, such as increased tread changes during bumps and rebound, and increased structural complexity at the drive shaft joint. You can freely set the rear wheel camber angle change during bumps and rebounds without causing any damage.
The first objective is to realize a new suspension mechanism that can be controlled, and to obtain optimal driving performance that matches the vehicle type and usage conditions of the vehicle.

Furthermore, the present invention provides a suspension that enables camber control during bumps and rebounds as described above, and is further configured to cause the rear wheel on the opposite side of the turning direction to behave in the toe-in direction during cornering. The second purpose is to improve vehicle stability or turning performance.

(Configuration of the Invention) The rear suspension according to the present invention is configured as follows in order to achieve the above object.

First, the basic structure of this rear suspension is a trailing arm that is connected to the vehicle body at one point via an elastic bushing so as to be able to swing up and down, and rotatably supports the rear wheel; a lateral link whose ends are rotatably connected to the trailing arms via ball joints to receive lateral forces acting on the rear wheel; and a can interposed between the trailing arm and the vehicle body. It has a bar control mechanism. This camber control mechanism includes a first control link whose base end is fixed to the trailing arm, one end of which is rotatably connected to the tip of the first control link, and the other end of which is rotatably connected to the vehicle body. and a second control link, and the vehicle body side connection point of the second control link is connected to the straight line connecting the vehicle body side connection point of the trailing arm and the vehicle body side connection point of the lateral link, that is, the semi-trailing axis. On the other hand, it is installed eccentrically by a set amount below the vehicle body. According to such a configuration, when the rear wheel attempts to swing vertically about the semi-trailing shaft during a bump or rebound, the camber control mechanism causes the wheel to move toward the vehicle body side in the trailing arm. It will be rotated around the camber center axis connecting the connection point and the lateral link connection point, but in that case, by appropriately setting the eccentricity and dimensions of the second control link in the camber control mechanism, It becomes possible to freely set and control the direction and amount of change in the camber angle of the rear wheel in response to bumps and rebounds.

Furthermore, in the rear suspension according to the present invention, in addition to the above configuration, the trailing arm side connection point of the lateral link is arranged rearward from the center of rotation of the rear wheel. The connection point between this lateral link and the trailing arm is the center of behavior of the rear wheel due to the lateral force acting on the rear wheel on the opposite side of the turning direction during cornering, and this point is located behind the center of rotation of the wheel. , the wheel is moved in the toe-in direction by the lateral force.

In the embodiment of the present invention, the connecting point of the lateral link on the training arm side is located behind the center of rotation of the rear wheel and on the outside of the vehicle body with respect to the center line in the width direction of the rear wheel. Therefore, the longitudinal force acting on the rear wheel from the front during braking also causes the wheel to behave in the toe-in direction.

(Example) Hereinafter, a rear suspension according to the present invention will be described based on an example shown in the drawings.

As shown in FIG. 1, this rear suspension 1 has a trailing arm 2, a lateral link 3, and a camber control mechanism 4 as main components, and a vehicle body 5 and a vehicle body side member. It is supported by a sub-frame 7 attached to the center of the vehicle body 5 at four locations on the front, rear, left and right through elastic bushes 6...6.

The trailing arm 2 has a distal end 2a pivotally supported by a bracket 8 fixed to the vehicle body 5 via an elastic bush 9, and a base end 2b disposed at the rear of the vehicle body that can swing freely in the vertical direction. has been done. Further, the lateral link 3 is installed diagonally between the base end 2b of the trailing arm 2 and the subframe 7, and both ends thereof are connected to the base end 2b of the trailing arm 2 and the subframe 7. are rotatably connected to each other via ball joints 10 and 11, respectively. A rear wheel 12 is rotatably supported on the base end 2b of the trailing arm 2.
is configured to be rotationally driven by an axle shaft 14 extending laterally from a differential gear 13 supported by the subframe 7, and the base end portion 2b of the trailing arm has an upper end connected to a spring attached to the vehicle body. and a damper.

On the other hand, the camber control mechanism 4 has a bolt 1 attached to the base end 2b of the trailing arm 2.
6, the first control link 17 has a base end 17a fixed thereto, and extends diagonally forward between the trailing arm 2 and the lateral link 3.
and a substantially vertical direction with one end 18a rotatably connected to a bracket 19 fixed to the subframe 7, and the other end 18b rotatably connected to the tip 17b of the first control link 17. and a second control link 18 arranged therein.

As shown in FIGS. 2 and 3, a connection point A on the vehicle body side (subframe side) of the second control link 18 in this camber control mechanism 4
(End portion 18a) is a straight line connecting the vehicle body side connection point B (tip portion 2a) of the trailing arm 2 and the vehicle body side (subframe side) connection point C (ball joint 11) of the lateral link 3, that is, a semi- It is installed eccentrically by a set amount a (see FIG. 3) with respect to the trailing axis XX.

In addition, the connection point D (ball joint 10) of the lateral link 3 on the trailing arm 2 side is
A position located behind the rotation center axis Y-Y of the rear wheel 12 by a set amount b (see FIGS. 2 and 3),
Further, it is disposed at a position outside the vehicle body by a set amount c (see FIG. 2) from the center axis Z-Z in the width direction of the wheel 12.

Next, the operation of the rear suspension 1 configured as described above will be explained.

First, to explain the relative behavior of the rear wheel 12 with respect to the vehicle body 5 during bumps and rebounds, the wheel 12 is connected to the vehicle body 5 via the trailing arm 2 and the lateral link 3.
It is supported by the subframe 7 attached to the vehicle body side connection point B of the trailing arm 2.
and subframe side connection point C of lateral link 3
Since both have a rotatable structure, the wheel 12 tends to swing up and down about the straight line (semi-trailing axis) XX connecting the two points B and C mentioned above. However, since the camber control mechanism 4 is interposed between the base end 2b of the trailing arm 2 and the subframe 7, the swinging around the semi-trailing axis XX is as follows. It will be corrected. That is, as shown in FIG. 4, when the trailing arm 2 swings in the A direction around the semi-trailing axis XX during a bump, the bolts 16, 16 are attached to the base end 2b of the trailing arm 2.
The tip end 17b of the first control link 17 is rigidly connected to the trailing arm 2 by
However, since the end 18b of the second control link 18 is connected to the tip 17b of the first control link 17, the Tip part 17b
is forcibly corrected to swing in the C direction about the subframe side connection point A of the second control link 18. As a result, when the connection point A is located below the semi-trailing axis XX as shown in the figure, the tip 17b of the first control link 17 is forcibly lifted upward according to the pump amount. become. Similarly, when the trailing arm 2 swings in the A' direction during rebound, the first control link tip 17
When b attempts to swing in the direction B', it is corrected in the direction C' and is forcibly lifted upward.

The trailing arm 2 has its distal end 2a connected to the vehicle body 5 via the elastic bush 9, and its base end 2b connected to the lateral link 3 via the ball joint 10. It is in a state in which it can rotate around a straight line connecting respective connection points B and D with the camber center axis W--W (see FIG. 2). Therefore, as mentioned above, when bumping or rebounding, the first control 1
When the tip 17b of the wheel 7 is lifted upward, the trailing arm 2 and the wheel 12 are rotated in two directions around the axis W-W, as shown in FIG. It will behave in the direction of

Here, if the wheel 12 swings around the semi-trailing axis XX without correcting its trajectory, for example, as shown in FIG. When tilted backwards, the wheel 12
behaves uniquely in the negative camber direction during bump and in the positive camber direction during rebound. However, due to the action of the camber control mechanism 4 as described above, for example, the positional relationship between the vehicle body side connection point A of the second control link 18 and the semi-trailing axis XX, the amount of eccentricity, or the length of the link 18 can be changed. or the connection point A and the first and second control links 1.
By reversing the vertical relationship with the connecting points 7 and 18, it becomes possible to freely set the direction and amount of change in the camber angle with respect to the amount of bump and rebound.

On the other hand, when the vehicle body is cornering, a lateral force F (see FIG. 2) acts from the outside on the rear wheel 12 on the opposite side to the turning direction. This lateral force F is received by the vehicle body 5 (subframe 7) via the lateral link 3, and the connection point D of the lateral link 3 with the trailing arm base end 2b is due to the rotation of the rear wheel 12. Since it is located behind the central axis Y-Y, the lateral force F causes the connection point D to
A moment M in the direction shown in FIG. 2 is generated around the . In that case, the connection point D is rotatable by the ball joint 10,
Further, the tip 2a of the trailing arm 2 is connected to the vehicle body 5.
Because it is connected to via the elastic bushing 9,
The moment M causes the trailing arm 2 to rotate around the connection D in the M direction. As a result, the rear wheel 12 also rotates in the same direction, that is, in the toe-in direction, but when the rear wheel on the opposite side to the turning direction becomes toe-in during cornering, the grip force of the wheel on the ground increases. This increases the stability or turning performance of the vehicle body during cornering.

Further, in this embodiment, since the trailing arm side connection point D of the lateral link 3 is disposed on the outer side of the vehicle body than the center line Z-Z in the width direction of the rear wheel 12, the rear wheel 12 is When a longitudinal force F' (see FIG. 2) is applied from the front, a moment M' in the same direction as the moment M is applied around the connecting point D due to the longitudinal force F'. Therefore, the rear wheel 12 will behave in the toe-in direction even during braking,
Particularly when braking during cornering, both of the moments M and M' act, making the toe-in effect even more pronounced, further improving the stability and turning performance of the vehicle body.

In the above embodiment, one end of the lateral link 3 and one end of the second control link 18 are connected to the vehicle body 5 via the subframe 7, but it is possible to connect these directly to the vehicle body. Good too.

(Effects of the Invention) As described above, according to the present invention, in an independent rear suspension, deterioration of straight-line stability due to large tread changes during bumps and rebound, tire wear, or drive shaft joint This makes it possible to freely set and control changes in the camber angle of the rear wheel during bumps and rebounds without complicating the structure of the parts. Thereby, driving performance such as straight-line performance and turning performance can be optimally set according to the type of vehicle to which the suspension is applied, usage conditions, and the like. Further, according to the present invention, the rear wheel on the opposite side to the turning direction is moved in the toe-in direction during cornering, thereby improving the stability or turning performance of the vehicle body during cornering.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a perspective view showing the overall structure of the rear suspension, FIG. 2 is a plan view, and FIG. 3 is a longitudinal sectional side view taken along the line shown in FIG. 2. , FIG. 4 is an enlarged side view of the main part showing the action, and FIG. 5 is a rear view of the main part showing the action. 1... Rear suspension, 2... Trailing arm, 3... Lateral link, 4... Camber control mechanism, 5... Vehicle body, 9... Elastic bushing, 10, 11... Ball joint, 12
...Rear wheel, 17...First control link, 18...Second control link.

Claims (1)

[Scope of Claims] 1. A trailing arm that is connected to the vehicle body at one point via an elastic bushing so as to be able to swing in the vertical direction and rotatably support the rear wheel; a lateral link rotatably connected to the trailing arm via a ball joint, a first control link whose base end is fixed to the trailing arm, and one end of which is the distal end of the first control link. and a second control link whose other end is rotatably connected to the vehicle body, and a connection point on the vehicle body side of the second control link is a connection point on the vehicle body side of the trailing arm and a connection point on the vehicle body side of the lateral link. The lateral link is installed eccentrically by a set amount below the vehicle body with respect to the straight line connecting the points, and the connecting point on the trailing arm side of the lateral link is located rearward from the center of rotation of the rear wheel. rear suspension. 2. The rear suspension for an automobile according to claim 1, wherein the connecting point on the trailing arm side of the lateral link is disposed on the outer side of the vehicle body from the center line in the width direction of the rear wheel.