JPH0433644B2 - - 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 bumps and rebounds. 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 backward from the outside of the vehicle to the inside. 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 the camber angle with respect to bumps and rebounds are uniquely determined by the direction of the semi-trailing axis. Therefore, driving performance can be freely adjusted by changing the camber angle, for example, by improving straight-line stability even with a small change in camber angle, or by increasing negative camber when bumping due to 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 with independent rear suspensions, and provides a new system that allows the camber angle change of the rear wheel to be freely set and controlled during bumps and rebounds. The first objective is to realize a suspension mechanism that provides optimal driving performance suited to the vehicle type, usage conditions, etc. of the vehicle.

In addition, the present invention further provides a suspension that enables camber control during bumps and rebounds as described above, and further minimizes changes in tread due to changes in camber angle to improve driving stability and reduce wear and tear on tires. In addition to trying to suppress the
Particularly when bumping, the configuration is such that the efficiency with which bump motion is converted into a change in camber angle increases as the amount of bump increases. For example, when a rear wheel on the opposite side of the turning direction makes a large bump during cornering, the A second object is to enable camber control such as effectively increasing negative camber to further improve turning performance.

(Structure of the Invention) The rear suspension according to the present invention has the following structure for the purpose described above.

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 via ball joints to the rear wheel support portions of the trailing arms to receive lateral forces acting on the rear wheels, and between the trailing arms and the vehicle body; and a camber control mechanism interposed therein. This camber control mechanism includes a first control link whose base end is fixed to the trailing arm, and whose one end is fixed to the first control link.
The tip of the control link includes a second control link whose other end is rotatably connected to the vehicle body, and the vehicle body side connection point of the second control link is the vehicle body side connection of the trailing arm. It is provided eccentrically by a set amount with respect to the straight line connecting the point and the connection point on the vehicle body side of the lateral link, that is, the semi-trailing axis. 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 is rotated around the camber center axis connecting the connection point and the lateral link connection point. In that case, by appropriately setting the eccentricity and dimensions of the second control link in the camber control mechanism, the direction and amount of change in the camber angle of the rear wheel in response to bumps and rebounds can be freely set and controlled. becomes possible.

Furthermore, in the rear suspension according to the present invention, in addition to the above configuration, the connection point between the lateral link and the trailing arm is located as low as possible, and is located below the connection point of the trailing arm on the vehicle body side. be done. Therefore, changes in tread due to changes in camber angle during bumps and rebounds are reduced. In addition, the camber center axis moves from being tilted backwards and downwards when the bump amount is zero or small, to becoming more horizontal as the bump amount increases, and the efficiency of converting the bump operation into a change in camber angle increases. growing. In other words, the camber angle effectively changes upon bumping.

(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 as a member on the vehicle body side. It is supported by a sub-frame 7 attached to the central part of the frame 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 obliquely forward between the trailing arm 2 and the lateral link 3.
and is arranged in 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.

As shown in FIGS. 2 and 3, the vehicle body side (subframe) connection point A (end portion 18a) of the second control link 18 in this camber control mechanism 4 is connected to the vehicle body side connection point B of the trailing arm 2. (Tip 2a) and the connection point C (ball joint 11) on the vehicle body side (subframe) side of the lateral link 3, that is, the setting amount a with respect to the semi-trailing axis XX (see Fig. 3) ) is set eccentrically.

Further, the connecting point D (ball joint 10) between the lateral link 3 and the base end 2b of the trailing arm 2 is located as low as possible, and is lower than the connecting point B of the trailing arm 2 on the vehicle body side. It is located.

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 connection point E 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, in the case of the illustrated positional relationship, the tip portion 17b of the first control link 17 is forcibly lifted upward in accordance with the bump amount. 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.

Further, as shown in FIG. 5, the connection point E' of the first and second control links 17' and 18' in the camber control mechanism 4' is connected to the subframe side connection point A' of the second control link 18'. If the trailing arm 2' is located in the middle of the vehicle body side connection point B', the bump of the trailing arm 2',
Semi-trailing axis X-X during rebound
The tip end 17b' of the first control link 17' (connection point E')
The connection point is when the is about to swing in the direction of
It is corrected in the C'' and C〓 directions with A' as the center, and is forcibly pushed downward.

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 connecting points B and D, that is, a camber center axis Y-Y (see FIGS. 2 and 3). Therefore, when the tip 17b of the first control link 17 is lifted upward or pushed downward during a bump or rebound as described above, the trailing arm 2 and rear wheel 12 are Rotation in two or two' directions around the camber center axis Y-Y will be applied, and the wheel 12 will behave in the positive camber direction in the former case, and in the negative camber direction in the latter case. .

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 bumps and in the positive camber direction during rebound. However, due to the action of the camber control mechanism 4 as described above, for example, in the case of the positional relationship shown in FIG. 4, the positive camber direction at the time of bump and rebound, and in the case of FIG.
The eccentricity a, a' between the semi-trailing axis XX and the 'subframe side connection points A, A' of the second control links 18, 18, or the link 18 can be moved in the negative camber direction. ，
By appropriately setting the length of 18', etc., it becomes possible to freely set the amount of change in the camber angle with respect to the amount of bump and rebound.

However, due to changes in the camber angle during bumps and rebounds as described above, the distance between the grounding points of the left and right rear wheels, that is, the tread, changes. That is, if the left and right rear wheels move in the positive camber direction, the tread decreases, and if they move in the negative camber direction, the tread increases. When the tread changes in this way during bumps and rebounds, running stability deteriorates when traveling straight and when turning.

However, in the present invention, as shown in FIG. 3, the connection point D between the lateral link 3, which is the rear wheel side reference point of the camber center axis Y-Y, and the base end 2b of the trailing arm 2 is located as downward as possible. Thus, the grounding point 12a of the rear wheel 12 and the camber center axis YY are brought close to each other. Therefore, the lateral displacement of the rear wheel grounding point 12a for a certain amount of camber angle change around the axis Y-Y, that is, the change in tread, is small, and the running stability is maintained even if the camber angle changes during bumps and rebounds. is ensured.

Also, the connection point D between the lateral link 3 and the trailing arm base end 2b, which is the rear reference point of the camber center axis Y-Y, is lower than the vehicle body side connection point B of the trailing arm 2, which is the front reference point. When the bump amount is zero or small, the camber center axis Y-Y is in a downwardly inclined state. Therefore, in this state, the change in the camber angle of the rear wheel 12 with respect to rotation at a constant angle about the axis Y-Y is smaller than when the camber center axis Y-Y is in the horizontal direction. In other words, the efficiency with which the bump motion of the rear wheel is converted into a change in camber angle is smaller than when the axis Y-Y is horizontal. To explain this relationship with reference to FIGS. 6 and 7, as shown in FIG. 6a, the rear wheel 1
2 rotates by a certain angle around the camber center axis Y-Y, each point on the circumference of the wheel 12 is displaced as shown by the arrow, but the displacement δ is as follows when the axis Y-Y is tilted. is decomposed into a displacement δ ₁ that appears as a camber angle change and a displacement δ ₂ that is unrelated to the camber angle change. Therefore, as shown in FIG. 6b, the camber angle change for the same rotation angle is smaller than when the camber center axis Y-Y is in the horizontal direction and the displacement δ' appears as a linear camber angle change. In other words, the efficiency with which rotation around the camber center axis Y-Y is converted into a change in camber angle increases as the inclination angle of the axis Y-Y decreases, as shown in FIG.

As a result, the camber angle does not change much even with a small bump when the camber center axis Y-Y is inclined, such as when a bump occurs when driving straight, and straight-line stability is obtained, and when cornering, the turning direction When the rear wheel on the opposite side makes a large bump, the camber angle change becomes noticeable. Therefore, if the camber control mechanism is arranged in the positional relationship shown in FIG. 5, for example, so that the rear wheel moves in the negative camber direction when bumping, the rear wheel on the opposite side to the turning direction will move in the negative camber direction when cornering. It moves significantly in the camber direction, increasing the grip force on the ground and improving turning performance.

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 also possible to connect these directly to the vehicle body. good.

(Effects of the Invention) As described above, according to the present invention, in an independent rear suspension, it is possible to freely set and control changes in the camber angle of the rear wheel during bumps and rebounds. 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. Furthermore, according to the present invention, changes in tread due to changes in camber angle during bumps and rebounds are reduced, straight-line stability is improved, tire wear is suppressed, and changes in camber angle are not noticeable during bumps. As a result, control such as, for example, making the rear wheel on the opposite side to the turning direction move significantly in the negative canvas direction during cornering becomes possible.Furthermore, according to the present invention, the structure of the joint part of the drive shaft becomes complicated, etc. This has the advantage of being avoided.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention; 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 side view taken along the line of FIG. Figure 4 is an enlarged side view of the main parts.
FIG. 5 is an enlarged side view of a main part of another embodiment, FIGS. 6a and 6b are schematic side views showing the effect, and FIG. 7 is a graph similarly explaining the effect. 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)

[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 vertically and rotatably support the rear wheel, and one end of which is connected to the vehicle body and the other end of which supports the rear wheel of the trailing arm. a lateral link that is rotatably connected to each other via a ball joint in the vicinity of the first control link, a first control link whose base end is fixed to the trailing arm, and one end of which is connected to the tip of the first control link. , 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 connecting point of the lateral link and the trailing arm is located as low as possible, and is located below the connecting point of the trailing arm on the vehicle body side. An automobile rear suspension characterized by: