JP2515364B2 - Wheel camber angle control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel camber angle control device, and more particularly to distribution of roll rigidity between front wheel side suspension devices and rear wheel side suspension devices according to a steering state of a vehicle. The invention relates to a wheel camber angle control device in which the vehicle movement performance is improved by changing

(Prior Art) In recent years, vehicles such as automobiles are highly required to have high-speed straight-line performance and high-speed turning performance.
For this reason, for example, a wheel camber angle control device has been proposed which controls the camber angle change of the wheel by devising a suspension device (see Japanese Utility Model Laid-Open No. 60-130108).

As shown in FIGS. 5 and 6, this device includes a suspension member 1, a transverse link 2, struts 3,
Strut type suspension 6 including mount insulator 4 and transverse link bush 5
The mount insulator 4 is mounted on the vehicle body 7 so that the axes of the struts 3 and the mount insulator 4 intersect with each other. Therefore, when the vehicle body 7 descends with respect to the wheel 8 grounded by rolling while the vehicle is turning, the transverse link 2 swings and the strut 3 is lifted with respect to the vehicle body 7, the mount insulator 4 has a low spring constant. It is deformed in the shearing direction (the direction of the center line C in FIG. 6), and the upper end of the strut 3 is moved inward of the vehicle. Therefore, the camber angle change of the wheels 8 due to the swing of the transverse ring 2 as shown by the phantom line in FIG. 6 is corrected, and the turning performance is improved.

(Problems to be Solved by the Invention) However, in such a conventional wheel camber angle control device, the camber angle of the wheel 8 is corrected by using the compliance of the mount insulator 4 based on the roll angle of the vehicle body 7. Because of the configuration, when a large lateral acceleration is applied to the vehicle body 7 due to high-speed turning or the like, in a vehicle in which the rear wheels are slippery, the turning performance is good when turning the steering wheel, but the convergence when returning is poor, and the front wheels are On the other hand, in a non-slip vehicle, the convergence was good but the turning performance was poor. In other words, the distribution of roll rigidity is constant between the front wheel and rear wheel suspensions of the vehicle, so if this distribution is too low or too high on the rear wheel side, both turning and convergence during turning will be stable. It becomes difficult to secure the stability, and there is a problem that the steering stability is deteriorated when turning at high speed.

(Object of the Invention) Therefore, according to the present invention, by changing the distribution of roll rigidity between the suspension devices on the front wheel side and the rear wheel side in accordance with the steering state of the vehicle, in particular, the turning property and the convergence property during turning are improved. It is aimed at achieving both compatibility and improving the dynamic performance and steering stability of the vehicle.

(Means for Solving the Problem) In order to achieve the above-mentioned object, the present invention is provided with a front wheel-side suspension device, and a first rigidity varying device capable of changing roll rigidity of the suspension device, Second rigidity changing means provided in the suspension device on the rear wheel side and capable of changing the roll rigidity of the suspension device, and steering state detecting means for detecting an increase or a return of the steering wheel from a change in the steering angular velocity. On the basis of the detection information from the steering state detecting means, when the steering handle is turned on, the roll rigidity of the suspension device on the front wheel side is increased and the roll rigidity of the suspension device on the rear wheel side is reduced to reduce the steering wheel rigidity. At the time of switching back, the roll rigidity of the suspension device on the front wheel side is reduced and the roll rigidity of the suspension device on the rear wheel side is increased.
A steering means for controlling the camber angle of the front wheels in the negative direction and the camber angle of the rear wheels in the positive direction when the steering wheel is turned. When the steering wheel is turned back, the camber angle of the front wheels is controlled in the positive direction and the camber angle of the rear wheels is controlled in the negative direction.

(Operation) In the present invention, the operation of the first stiffness varying means and the second stiffness varying means is controlled by the control means based on the detection information from the steering state detecting means, and the suspension on the front wheel side is performed when the steering wheel is further turned. As the roll rigidity of the device is increased, the roll rigidity of the suspension device on the rear wheel side is reduced, and when the steering handle is turned back, the roll rigidity of the suspension device on the front wheel side is decreased and the roll rigidity of the suspension device on the rear wheel side is reduced. Roll rigidity is increased. When the steering wheel is turned further, the camber angle of the front wheels is controlled in the negative direction and the camber angle of the rear wheels is controlled in the positive direction.When the steering wheel is turned back, the camber angle of the front wheels is controlled in the positive direction and the camber angle of the rear wheels is controlled. Are controlled in the negative direction. Therefore, the distribution of roll rigidity is changed between the suspensions on the front and rear wheels in accordance with the steering state of the vehicle, and the camber angle is controlled so that both the turning performance and the convergence performance during turning are stable. It As a result, the dynamic performance and steering stability of the vehicle are improved.

(Example) Hereinafter, the present invention will be described with reference to the drawings.

1 and 2 are views showing a first embodiment of the present invention, and the first embodiment is an application of the present invention to a suspension system of a MacPherson strut system.

In FIG. 1, reference numeral 11 is a suspension member, 12 is a transverse link, and 13 is a strut. The transverse link 12 is supported by the suspension member 11 at its inner end portion so as to be vertically swingable. There is. The strut 13 has a lower end 13a connected to the outer end of the transverse link 12 and an upper end 13b connected to the vehicle body 16 via the mount insulator 14 and the bracket 15, and the lower end 13a of the strut 13 is provided. Is the front wheel 17F or rear wheel 17R axle housing (not shown)
Attached to. These suspension members 1
1, a plurality of transverse links 12, struts 13, mount insulators 14, brackets 15 and the like are provided corresponding to the front wheels 17F and the rear wheels 17R, and the front suspension 18 (suspension device on the front wheel 17F side) and the rear suspension 19 (rear wheels). 17R side suspension system).

Further, the mount insulator 14 is a fluid-filled type in which an incompressible fluid or the like is enclosed, and has, for example, a plurality of fluid chambers 14a, 14b symmetrically arranged with the upper end portion 13b of the strut 13 interposed therebetween. are doing. The fluid chambers 14a and 14b of the mount insulator 14 are connected to each other via a pipe 21, and are opened and closed by an electromagnetic valve 22 provided on the pipe line of the pipe 21 to communicate with and cut off from each other. The mount rigidity of the fluid chamber 14 is changed by connecting and disconnecting the fluid chambers 14a and 14b. Further, the pair of left and right electromagnetic valves 22 provided on the front suspension 18 are controlled to be opened and closed by a control signal V ₁ from a control means described later, and the pair of left and right electromagnetic valves 22 provided on the rear suspension 19 are controlled by the control means. The opening / closing control is performed by a control signal V ₂ of each of the front suspension 18 and the rear suspension by changing the mount rigidity of the left and right mount insulators 14 by each pair of electromagnetic valves 22.
The roll rigidity of 19 can be changed. That is, the first rigidity varying means 23 capable of changing the roll rigidity of the front suspension 18 by the pair of left and right mount insulators 14, the pipe 21 and the electromagnetic valve 22 provided in the front suspension 18.
And a pair of left and right mount insulators 14 provided on the rear suspension 19, a pipe 21 and an electromagnetic valve 22 constitute a second rigidity varying means 24 capable of changing the roll rigidity of the rear suspension 19. There is.

Reference numeral 25 is a steering state detecting means, and the steering state detecting means 25 comprises a steering angular velocity sensor 26 and a lateral acceleration sensor 27. The steering angular velocity sensor 26 detects a steering angle of a steering wheel (not shown) and gives a steering angular velocity signal which is detection information to the control means 28. This steering angular velocity signal is, for example, positive when the steering direction of the steering handle is right, and is negative when the steering direction is left. Further, the lateral acceleration sensor 27 is attached to the suspension member 11 of the front suspension 18, and the lateral acceleration sensor 27 is used for turning the vehicle body 16 when turning.
The lateral acceleration acting on the is detected, and the lateral acceleration signal which is the detected information is given to the control means. This lateral acceleration signal adds the lateral acceleration that acts on the vehicle body 16 during a right turn,
The lateral acceleration acting on the vehicle body 16 during a left turn is negative. Then, from these detection signals, the turning direction and steering direction (steering angle increasing direction, returning direction, etc.), which are the steering states of the vehicle, can be detected.

The control means 28 is composed of a microcomputer, a switch circuit, etc., and is based on the steering angular velocity signal and the lateral acceleration signal from the steering state detection means 25, and the above-mentioned control signal
A predetermined program is stored in the microcomputer of the control means 28 so as to output V ₁ and V ₂ . That is,
The control means 28 urges each electromagnetic valve 22 to open based on the detection information from the steering state detection means 25, and the first rigidity varying means 23.
The operation of the second stiffness varying means 24 is controlled, and the first stiffness varying means 23 and the second stiffness varying means 24 controlled by the control means 28 control the front suspension 18 when the steering wheel is turned. The roll rigidity of the rear suspension 19 is reduced while the roll rigidity of the rear suspension 19 is reduced, and the roll rigidity of the rear suspension 19 is increased when the steering handle is turned back. When the vehicle body 16 is turning and the steering wheel is turned, the mount insulator 14
By suppressing the camber angle change of the front wheel 17F due to the compliance of the roll wheel by increasing the roll rigidity, the camber angle change of the rear wheel 17R is promoted in the negative direction (direction inclining inward of the vehicle) by reducing the roll rigidity. Controls in the positive direction (direction in which the vehicle leans outward), and when the steering wheel is turned back, the camber angle change of the front wheel 17F due to the compliance of the mount insulator 14 is promoted in the positive direction by reducing the roll rigidity. The change in camber angle of the rear wheel 17R is suppressed by increasing the roll rigidity and is controlled in the positive direction.

 Next, the operation will be described.

When the steering angular velocity signal and the lateral acceleration signal from the steering state detecting means 25 are given to the control means 28, the control means
By 28, the processing as shown in FIG. 2 is executed every predetermined time. First, the values of the steering angular velocity signal and the lateral acceleration signal are grasped, and then the product of both signals is obtained to determine which of the steering states A and B is described below.

Now, for example, when a vehicle traveling straight ahead (forward) is steered to the right or left, when the steering wheel is steered to the right, the steering angular velocity signal changes to plus (> 0) and the lateral acceleration signal changes. When it changes from 0 to plus and is steered to the left, the steering angular velocity signal changes to minus (<0) and the lateral acceleration signal y changes from 0 to minus. In this case, the product of both signal values is always positive (> 0)
Alternatively, it becomes 0 (when = 0), and the steering state A is determined. Then, when the vehicle turning after being steered to the right or left is steered (returned) in a straight direction,
When the steering wheel is turned back to the left, the steering angular velocity signal changes to minus (<0), the lateral acceleration signal remains positive (while turning right), and when turned back to the right, the steering angular velocity signal becomes positive. It changes to (> 0) and the lateral acceleration signal remains negative (while turning left). In this case, the product of both signal values is always negative (<0), and the control means 28 determines that the steering state is B. Further, when the vehicle is traveling straight ahead after the turning back is completed or the vehicle is held at a constant steering angle (when θ = 0), the steering state B is determined.

Next, when the control means 28 determines the steering states A and B, that is, whether the steering wheel is turned or turned back (including the steering holding state), the control means 28 causes the first stiffness varying means 23 and The control signal V ₁ is sent to the second stiffness varying means 24,
V ₂ is output. At this time, when the determination result is the steering state A, the electromagnetic valve 22 of the first rigidity varying means 24 is closed by the control signal V _{1 and} the electromagnetic valve 22 of the second rigidity varying means 24 is closed by the control signal V ₂ . On the other hand, when the discrimination result is the steering state B, the electromagnetic valve 22 of the first stiffness varying means 23 is opened by the control signal V _{1 and} the electromagnetic type of the second stiffness varying means 24 is opened by the control signal V ₂ . Valve 22 closes. Therefore, when the steering wheel is being increased, the roll rigidity of the front suspension 18 is increased and the front wheels 17
The camber angle of F is controlled in the negative direction, the roll rigidity of the rear suspension 19 is reduced, and the camber angle of the rear wheel 17R in the positive direction is promoted. Also, when the steering wheel is turned back or held, the roll rigidity of the front suspension 18 is reduced and the front wheels 17F
The change in the camber angle in the positive direction is promoted, the roll rigidity of the rear suspension 19 is increased, and the camber angle of the rear wheel 17R is controlled in the negative direction. Therefore, when the steering wheel is turned to turn the vehicle, the camber angle of the wheels is controlled so that the tail slide is facilitated and the turning performance of the vehicle is promoted.When the steering wheel is turned back, the tail flow is suppressed. The camber angle of the wheels is controlled so as to promote convergence.

As described above, in the present embodiment, the distribution of roll rigidity is changed between the front suspension 18 and the rear suspension 19 in accordance with the steering state of the vehicle, and in particular, both the turning ability and the convergence ability during high-speed turning are stable. Since the camber angle of the wheels is controlled so that the vehicle motion performance and steering stability are improved. Furthermore, it has been very difficult to achieve both maneuverability and stability in the area near the limit steering in the past, but when steering during turning, the control moment and reverting (including countersteering) when turning up are included.
Since the restoring moment at the time can be increased together, the maneuverability in the limit region including drift running is significantly improved.

FIGS. 3 and 4 are views showing a second embodiment of the present invention. In FIG. 3, a fluid sealing bush 31 is provided at each of two connecting portions of the suspension member 11 of the front suspension 18 and the transverse link 12. ing. Each fluid enclosing bush 31 has two fluid chambers arranged on both sides in the longitudinal direction of the transverse link 12 with the connecting bolt 12a interposed therebetween.
The fluid chambers 31a and 31b are filled with incompressible fluid or the like. Further, both fluid-filled bushes 31 constitute the first stiffness varying means 34 together with the pipe 32 and the electromagnetic valve 33 similar to those in the first embodiment.
A control signal V ₁ from the control means 28 increases / decreases the rigidity of the pair of left and right fluid-filled bushes 31 with respect to the compressive load and the tensile load acting on the transverse link 12 during vehicle turning, thereby increasing the roll rigidity of the front suspension 18. Can be changed. In addition, the rear suspension 19 is also the first
A second stiffness varying means (not shown) similar to the stiffness varying means 34 is provided, which receives the control signals V ₁ and V ₂ from the control means 28 and receives the front signal in accordance with the steering state of the vehicle. Since the distribution of roll rigidity of the suspension 18 and the rear suspension 19 is changed, the same effect as that of the first embodiment can be obtained.

(Effect) According to the present invention, the first stiffness varying means and the second stiffness varying means are controlled by the control means based on the detection information from the steering state detecting means.
By controlling the operation of the rigidity varying means, the roll rigidity of the suspension system on the front wheel side is increased when the steering wheel is increased, and the roll rigidity of the suspension system on the rear wheel side is reduced. The roll rigidity of the suspension system is reduced and the roll rigidity of the suspension system on the rear wheel side is increased, and when the steering wheel is increased, the camber angle of the front wheel is set in the negative direction and the camber angle of the rear wheel is set in the positive direction. When the steering wheel is turned back, the front wheel camber angle is controlled in the positive direction and the rear wheel camber angle is controlled in the negative direction.Therefore, depending on the steering state of the vehicle, the front wheel side and the rear wheel side are suspended. By changing the distribution of roll rigidity between the devices, the camber angle can be controlled so that both the turning and convergence properties are stable, especially during high-speed turning. Can. As a result, the dynamic performance and steering stability of the vehicle can be improved.

[Brief description of drawings]

FIGS. 1 and 2 are diagrams showing a first embodiment of a wheel camber angle control device according to the present invention. FIG. 1 is a schematic configuration diagram thereof, FIG. FIG. 1 is a diagram showing a second embodiment of a wheel camber angle control device according to the present invention, FIG. 3 is a schematic configuration diagram thereof, FIG. 4 is a perspective view of its essential parts, and FIGS. It is a figure which shows,
FIG. 6 is a schematic configuration diagram thereof, and FIG. 6 is a cross-sectional view of its main part. 17F …… front wheel, 17R …… rear wheel, 18 …… front suspension (front wheel side suspension), 19 …… rear suspension (rear wheel side suspension), 23,34 …… first stiffness varying means, 24 ...... Second rigidity changing means, 25 ...... Steering state detecting means, 28 ...... Control means.

Claims (1)

(57) [Claims] 1. A first rigidity varying means provided on a suspension device on a front wheel side and capable of changing roll rigidity of the suspension device; and a roll rigidity of the suspension device provided on a suspension device on a rear wheel side. Second rigidity varying means that can be changed, steering state detecting means that detects whether steering wheel is further turned or turned back based on a change in steering angular velocity, and steering wheel based on detection information from the steering state detecting means When the steering wheel is turned up, the roll rigidity of the suspension system on the front wheel side is increased and the roll rigidity of the suspension system on the rear wheel side is reduced, and when the steering wheel is turned back, the roll rigidity of the suspension system on the front wheel side is reduced and Control means for controlling the operation of the first rigidity varying means and the second rigidity varying means so as to increase the roll rigidity of the suspension device on the wheel side, Sometimes the front wheel camber angle is controlled in the negative direction and the rear wheel camber angle is controlled in the positive direction.When the steering wheel is turned back, the front wheel camber angle is controlled in the positive direction and the rear wheel camber angle is controlled in the negative direction. A wheel camber angle control device characterized by the above.