JPH0433646B2 - - 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 moves in the 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 the 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 rearward from the outside to the inside of the vehicle body. As a result, during bumps (when the wheel moves upwards relative to each other), the camber angle changes in the direction of negative camber, 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 improved by changing 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 during bumps during cornering to improve maneuverability. You will no longer be able to set it freely.

(Object of the Invention) The present invention addresses the above-mentioned problems of independent rear suspensions, and provides a new suspension that can freely set and control changes in the camber angle of the rear wheel during bumps and rebounds. The purpose of this invention is to realize a driving mechanism that provides optimal driving performance suited to the usage conditions of the vehicle. In particular, in the present invention, the mechanism that governs such changes in the camber angle is provided with means for automatically adjusting the camber angle or its change characteristics according to the driving condition of the vehicle, so that, for example, when driving straight, the change in the camber angle is reduced. To improve straight running stability, or to improve turning performance by adjusting the rear wheel on the opposite side to the turning direction to a negative camber state during cornering.

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

That is, this rear suspension includes a training arm that is vertically swingably connected to the vehicle body via an elastic pusher and rotatably supports the rear wheel, and a canvas interposed between the training arm and the vehicle body. It has a 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 a connection point on the vehicle body side of the second control link is provided eccentrically by a set amount with respect to the swing center axis of the trailing arm, that is, the semi-trailing axis. And to this camber control mechanism,
A camber change amount adjusting means is provided for changing the camber amount depending on the running state of the vehicle. 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 to the camber center which extends in the longitudinal direction of the vehicle body. In this case, by appropriately setting the dimensions of the first and second control links in the camber control mechanism, the camber angle of the rear wheel against bumps and rebounds can be adjusted. It becomes possible to freely set the direction and amount of change.

Then, by the camber change amount adjusting means,
The camber angle of the rear wheel or the change characteristics of the camber angle during bumps, rebound, etc. are automatically adjusted according to the driving conditions.

The trailing arm may be connected to the vehicle body at two points as shown in the above-mentioned publication, but it may also be connected to the vehicle body at one point as shown in the following embodiments. In that case, a lateral link is provided to support the lateral forces acting on the rear wheel.

(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 training 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.
One end is rotatably connected to a bracket 19 fixed to the subframe 7, and the other end is connected to the tip 17b of the first control link 17.
and a second control link 18 arranged substantially in the vertical direction and rotatably connected to the second control link 18 .

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
is the swing center axis of the trailing arm 2 that connects 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, it is installed eccentrically by a set amount a (see FIG. 3) with respect to the semi-trailing axis XX.

Further, the length of the second control link 18 is adjustable as shown in enlarged form in FIGS. 1 and 4. That is, as shown in FIG. 4, the link 18 includes a cylinder 18a, a piston 18b fitted in the cylinder 18a, and a piston 18b.
The piston rod 18c is connected to the piston rod 18c, and the piston part 18d is fixed to the end of the cylinder 18a. 1 control link 17 and the bracket 19, respectively.

The switching is performed in response to signals from a fluid circuit 21 including a switching valve 20 that controls the supply of fluid to the cylinder device (second control link) 18 and a driving state detection sensor 22 that detects the driving state of the vehicle. Control device 23 for actuating valve 20
are provided. The fluid circuit 21 includes a discharge passage 21a extending from the discharge side of the fluid pump 24 to the switching valve 20 via the pressure accumulator 25, a suction passage 21b between the switching valve 20 and the pump suction side, and a suction passage 21b from the switching valve 20 to the switching valve 20. First and second fluid supply/discharge passages 21 leading to a chamber 18f below the piston and a chamber 18g above the piston in the cylinder 18a of the cylinder device 18, respectively.
c, 21d, and the discharge passage 21a is connected to the first supply/discharge passage 21 by the operation of the switching valve 20.
c, if the suction passage 21b is connected to the second supply/discharge passage 21d, fluid is introduced into the chamber 18f below the piston and fluid in the upper chamber 18g is discharged, thereby increasing the link length; Conversely, the discharge passage 21a becomes the second supply/discharge passage 21d, and the suction passage 21
b are respectively connected to the first supply/discharge passage 21c, the link length is reduced. Furthermore, in this example,
The running state detection sensor 22 is equipped with a turning sensor that detects turning of the automobile based on the steering angle of the steering wheel, roll angle of the vehicle body, lateral acceleration acting on the vehicle body, etc. When receiving the signal _S1 indicating the pumping state, the control device 23 connects the discharge passage 21a and the first supply/discharge passage 21c to the switching valve 20, and connects the suction passage 2
1b and the second supply/discharge passage 21d are configured to output a control signal _S2 .

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

First, the relative movement of the rear wheel 12 with respect to the vehicle body 5 during bumps and rebounds will be explained.
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. 5, 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 second control link 18 is connected to the tip 17b of the first control link 17, the tip 17b The second control link 18 is forcibly corrected to swing in the C direction about the subframe side connection point A. As a result, in the case of the arrangement shown in the figure, the first control link 1 is adjusted according to the bump amount.
7 is forcibly lifted upward. Similarly, when the trailing arm 2 swings in the A′ direction during rebound,
The first control link tip 17b, which is about to swing in the B' direction, is corrected in the C' direction and is forcibly lifted upward.

By the way, the trailing arm 2 has a tip portion 2a.
is connected to the vehicle body 5 via the elastic bush 9, and the base end 2b is connected to the lateral link 3 via the ball joint 10. The connecting straight line, that is, the camber center axis Y-Y (see Figure 2)
It can be rotated around. Therefore, when the tip 17b of the first control link 17 is lifted upward during a bump or rebound as described above, the trailing arm 2 and the wheel 12 are rotated around the axis Y-Y as shown by the chain line x in FIG. The wheel 12 is rotated in two directions, causing the wheel 12 to move in the positive camber direction.

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
The ball moves primarily in the negative canvas direction during a bump, and in the positive canvas direction during a rebound. However, due to the action of the camber control mechanism 4 as described above, bumps and rebounds may occur due to the positional relationship and eccentricity between the vehicle body side connection point A of the second control link 18 and the semi-trailing axis XX, etc. This makes it possible to freely set the direction and amount of change in the camber angle relative to the amount.

The second control link 18 is constituted by a cylinder device, and its length is changed by fluid supply and discharge control by a fluid circuit 21 shown in FIG. That is, in the case of this embodiment, when the vehicle is cornering, the turning sensor 2
The control device 23 receives the signal _S1 from the switching valve 2.
0 in a predetermined direction, fluid is introduced into the chamber 18f below the piston of the cylinder 18a in the second control link (cylinder device) 18, and fluid in the upper chamber 18g is discharged. The length of the link 18 is increased. Therefore, the tip end 17b of the first control link 17 is pushed down as shown by the chain line in FIG. 5, and as a result, the rear wheel 12 is moved toward the camber center axis It is rotated around -Y in the two' direction, that is, in the direction of the negative canvas.
In this way, when the rear wheel (especially the rear wheel on the opposite side to the turning direction) is placed in a negative canvas state during corner linking, the grip force on the ground increases and turning performance is improved. .

By the way, the second control link 18 mentioned above
The change in link length is due to the bump on the rear wheel 12,
Although the camber angle of the wheel 12 is changed regardless of rebound, the characteristics of the camber angle change during bumps and rebound also change depending on the change in link length. Therefore, the control effect on the camber angle change characteristics during bumps and rebounds due to the amount of eccentricity of the second control link 18 with respect to the semi-trailing axis XX, and the control effect on the camber angle itself due to changes in link length are synergized. In addition, if necessary, by adding a sensor that detects the amount of bumps and vertical acceleration of the vehicle body as the driving state detection sensor 22, for example, when driving straight, bumps due to unevenness of the road surface, etc., and camber angle when rebounding can be detected. By minimizing the change in stability to improve straight-line stability, and by putting the rear wheel into negative camber during cornering as described above to improve maneuverability, the camber is always optimized to suit various driving conditions. It can be set so that characteristics of angle or camber angle changes can be obtained.

In the above embodiment, the negative 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 preferable to connect these directly to the vehicle body. It's okay. Alternatively, the lateral link may be abolished and the trailing arm may be connected to the vehicle body at two points via elastic bushings.

(Effects of the Invention) As described above, according to the present invention, in an independent rear suspension, it is possible to freely set the characteristics of the camber angle change of the rear wheel during bumps and rebounds, and furthermore, It becomes possible to automatically adjust the camber angle or its change characteristics depending on the driving condition. This makes it possible to always control the camber angle to the optimum state depending on each driving condition, for example, improving straight-line stability when traveling straight and improving turning performance when turning.

[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 a control circuit diagram of the embodiment, FIG. 5 is an enlarged side view of main parts showing the operation, and FIG.
The figure is a rear view of the main part showing the same effect. 1... Rear suspension, 2... Trailing arm, 4... Camber control mechanism, 5
... Vehicle body, 9 ... Elastic bushing, 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 via an elastic bushing so as to be swingable in the vertical direction and rotatably supports the rear wheel, and a first control link and a second control link that connect the vehicle body and the trailing arm. The suspension has a camber control mechanism interposed between the arm and the camber control mechanism, wherein a first control link in the camber control mechanism has a base end fixed to the trailing arm, and a second control link. are arranged substantially vertically, one end is rotatably connected to the tip of the first control link, the other end is rotatably connected to the vehicle body, and the connection point on the vehicle body side of the second control link is connected to the swing of the trailing arm. It is installed eccentrically by a set amount with respect to the central axis, and the camber control mechanism has a
A rear suspension for an automobile, characterized in that it is provided with a camber change amount adjusting means for changing the camber amount according to the driving condition of the vehicle.