JPH01197109A - Controlling device for wheel camber angle - Google Patents

Abstract

PURPOSE:To make the head turning ability and convergence ability at turning compatible with each other by increasing one of the right and left roll rigidities of front and rear respective suspensions as well as decreasing the other of the right and left roll rigidities corresponding to the driving condition of a vehicle so as to control respective camber angles of front and rear wheels. CONSTITUTION:Front and rear respective suspensions 18 and 19 respectively paired with the right and the left are provided with mount insulators 14, pipes 21, and electromagnetic valves 22 respectively paired with the right and the left to compose first and second respective rigidity varying means 23 and 24. On the other hand, a driving condition detecting means 25 is provided to input its detected signal into a control means 28. Respective electromagnetic valves 22 are respectively opened or closed by the control means 28 to control the first and second respective rigidity varying means 23 and 24. Thereby, corresponding to the driving condition of a vehicle, one of the respective roll rigidities in the front and rear respective suspensions 18 and 19 is increased as well as the other is decreased, thus respective camber angles of respective front wheels 17F and respective rear wheels 17R are controlled respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a wheel camber angle control device, and more specifically, to a wheel camber angle control device that distributes roll stiffness between front and rear wheel suspension systems according to the steering condition of a vehicle. The present invention relates to a wheel camber angle control device that improves the dynamic performance of a vehicle by changing the camber angle.

(Prior Art) In recent years, vehicles such as automobiles are highly required to have dynamic performance such as high-speed straight running performance and high-speed turning performance. For this reason, a wheel camber angle control device has been proposed that suppresses and controls changes in the camber angle of the wheel by, for example, devising a suspension system (see Japanese Utility Model Application Publication No. 130108/1983, etc.).

As shown in Fig. 5.6, this device is composed of a strut-type suspension 6 consisting of a suspension member 1, a transverse link 2, a strut 3, a mount insulator 4, a transverse link bushing 5, etc. The mount insulator 4 is attached to the vehicle body 7 so that the axes of the strut 3 and the mount insulator 4 intersect. Therefore, the vehicle body 7
When the transverse link 2 swings and the strut 3 is lifted relative to the vehicle body 7, the mount insulator 4 is deformed in the shearing direction with a low spring constant (direction of the center line C in Fig. 6), and the strut 3 is adapted to be moved inward of the vehicle. Therefore, the change in the camber angle of the wheel 8 due to the swinging of the transverse link 2 as shown by the imaginary line in FIG. 6 is corrected, and the turning performance is improved.

(Issue 8 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 using the compliance of the mount insulator 4 based on the roll angle of the vehicle body 7. Therefore, when large lateral acceleration is applied to the vehicle body 7 due to high-speed turning, etc., in vehicles where the rear wheels are prone to slipping, the turning performance when turning the steering wheel is good, but the convergence performance when turning back is poor. Conversely, in vehicles where the front wheels were less slippery, the convergence was good, but the retrospective performance was poor. In other words, since the distribution of roll stiffness is constant between the front and rear suspensions of the vehicle, if this distribution is too low or too high on the rear wheels, both turning and convergence during turns will be affected. There was a problem in that it became difficult to ensure stability, resulting in a decrease in maneuvering stability during high-speed turns.

(Objective of the Invention) Therefore, the present invention aims to improve retrospective performance and convergence during turns by changing the distribution of roll stiffness between the front wheel and rear wheel suspension systems according to the steering state of the vehicle. Make it compatible,
The purpose is to improve the vehicle's driving performance and handling stability.

(Means for Solving the Problems) In order to achieve the above object, the present invention includes a first rigidity variable means that is provided in a suspension system on the front wheel side and is capable of changing the roll rigidity of the suspension system; a second rigidity variable means provided in a suspension system on the rear wheel side and capable of changing the roll rigidity of the suspension system; a steering state detection means for detecting a steering state of the vehicle; and a steering state detection means. control means for controlling the operation of the first variable stiffness means and the second variable stiffness means based on the detection information of the first stiffness variable means; This reduces the roll stiffness of the front and rear wheels and controls the camber angles of the front and rear wheels.

(Function) In the present invention, the control means controls the operation of the first stiffness variable means and the second stiffness variable means based on the detection information from the steering state detection means, so that the front wheel side The roll rigidity of one side of the rear wheel suspension system is increased and the roll rigidity of the other side is decreased, thereby controlling the camber angles of the front wheels and the rear wheels. Therefore, the distribution of roll stiffness is changed between the front and rear wheel suspension systems depending on the steering state of the vehicle, and the camber angle is controlled to stabilize both turning and convergence, especially when turning. Ru. As a result, the driving performance and steering stability of the vehicle are improved.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 1.2 is a diagram showing the first embodiment of the present invention, and the first
In this embodiment, the present invention is applied to a MacPherson strut type suspension system.

In FIG. 1, 11 is a suspension member 12, a transverse link, and 13 is a strut, and the transverse link 12 is supported by the suspension member 11 at its inner end on the inward side of the vehicle so as to be able to swing vertically. . The strut 13 has a lower end 13a connected to the outer end of the transverse link 12 and a mount insulator 1.
4 and an upper end 13b connected to the vehicle body 16 via a bracket 15, and the lower end 13a of the strut 13 is further attached to an axle housing (not shown) of a front wheel 17F or a rear wheel 17R. There is. These suspension members 11, transverse links 12, struts 13, mount insulators 1
4 and bracket 15 etc. are front wheel 17F and rear wheel 17
Multi-stage suspension corresponding to R, front suspension 1
8 (suspension device on the front wheel 17F side) and a rear suspension 19 (suspension device on the rear wheel 17R side).

The mount insulator 14 is of a fluid-filled type in which an incompressible fluid or the like is sealed, and has, for example, a plurality of fluid chambers 14a, 14b, etc. arranged symmetrically across the upper end 13b of the strut 13. are doing. The fluid chambers 14a and 14b of the mount insulator 14 are connected to each other via a pipe 21, and are communicated with and disconnected from each other by opening and closing an electromagnetic valve 22 provided on the pipe 21. 14 is adapted to change its mount rigidity by communicating and blocking the fluid chambers 14a and 14b. Further, a pair of left and right electromagnetic valves 22 provided on the front suspension 18 are controlled to open and close by a control signal v1 from a control means, which will be described later. Opening and closing are controlled by a control signal V2, and each pair of electromagnetic valves 22 changes the mount rigidity of the left and right mount insulators 14, thereby controlling the front suspension 18 and the rear suspension 1.
9 roll rigidity can be changed. That is, a pair of left and right mount insulators 14 and piping 21 provided on the front suspension 18
and a first stiffness variable means 23 that can change the roll stiffness of the front suspension 18 by means of an electromagnetic valve 22.
A pair of left and right mount insulators 14 provided at 9
, a pipe 21 and an electromagnetic valve 22 constitute a second rigidity variable means 24 that can change the roll rigidity of the rear suspension 19.

25 is a steering state detection means;
consists of a steering angular velocity sensor 26 and a lateral acceleration sensor 27. The steering angular velocity sensor 26 detects the steering angle of a steering wheel (not shown) and provides a steering angular velocity signal, which is detected information, to the control means 28. This steering angular velocity signal is, for example, positive when the steering direction of the steering wheel is to the right, and negative when the steering direction is to the left. Further, the lateral acceleration sensor 27 is attached to the suspension member 11 of the front suspension, and the lateral acceleration sensor 27 detects the lateral acceleration acting on the vehicle body 16 when turning, etc., and outputs a lateral acceleration signal y as detection information. to the control means 28.

This lateral acceleration signal y has a positive value for lateral acceleration acting on the vehicle body 16 during a right turn, and a negative value for a lateral acceleration acting on the vehicle body 16 during a left turn. From these detection signals δ and y, it is possible to detect the steering state of the vehicle, such as the turning direction and the steering direction (direction of increasing steering angle, direction of turning back, etc.).

The control means 28 is composed of a microcomputer, a switch circuit, etc., and the microcomputer of the control means 28 is configured to output the above-mentioned control signals V+ and Vz based on the steering angular velocity signal y and the lateral acceleration signal y from the steering state detection means 25. A predetermined program is stored in the .

That is, the control means 28 prompts the opening of each electromagnetic valve 22 based on the detection information from the steering state detection means 25, and controls the operation of the first variable stiffness means 23 and the second variable stiffness means 24. The front suspension 1 is controlled by the first stiffness variable means 23 and the second stiffness variable means 24 controlled by the control means 28 according to the steering state of the vehicle.
The roll stiffness of one of the suspension 8 and the rear suspension 19 is increased, while the roll stiffness of the other is decreased. When the vehicle body 16 rolls during a turn, the change in the camber angle of the front wheels 17F and rear wheels 17R due to the compliance of the mount insulator 14 is suppressed by increasing the roll rigidity, so that the vehicle body 16 rolls in a negative direction (direction in which the vehicle falls inward). This camber angle change is promoted by controlling or reducing the roll stiffness, and is controlled in a positive direction (direction in which the vehicle falls outward).

Next, the effect will be explained.

When the steering angular velocity signal S and the lateral acceleration signal y from the steering state detection means 25 are applied to the control means 28, the control means 28 executes the process shown in FIG. 2 at predetermined time intervals. First, the values of the steering angular velocity signal δ and the lateral acceleration signal V are grasped, and then the product of both signals is calculated to determine which of the steering shapes BA and B described below.

Now, for example, when a vehicle traveling straight (forward) is steered to the right or left, when the steering wheel is steered to the right, the steering angular velocity signal δ changes to plus (>0) and the lateral acceleration signal changes. When y changes from O to plus and the vehicle is steered to the left, the steering angular velocity signal dip changes to minus (kuO) and the lateral acceleration signal y changes from O to minus.

In this case, the product of both signal values is always positive (>0) or O (when V=0), and steering state A is determined.

Next, when the turning vehicle is steered straight ahead after being steered to the right or left, when the steering wheel is steered back to the left, the steering angular velocity signal becomes negative (kuO). When the steering angular velocity signal δ changes to positive (〉O) and the lateral acceleration signal y remains positive (during a right turn), the steering angular velocity signal δ changes to positive (〉O) and the lateral acceleration signal y remains negative (during a left turn). ) remains. In this case, the product of both signal values is always negative (<0), and the control means 28 determines that the steering condition is IB. Further, when the steering is completed and the vehicle travels straight or is kept 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 state), the control means 28 determines that the first
Control signals V, , V2 are output to the stiffness variable means 23 and the second stiffness variable means 24.

At this time, if the determination result is the steering condition gA, the control signal V causes the electromagnetic valve 22 of the first stiffness variable means 23 to
closes, and the control signal V2 opens the electromagnetic valve 22 of the second variable stiffness means 24. On the other hand, if the determination result is steering state B, the control signal V1 causes the electromagnetic valve 22 of the first variable stiffness means 23 to open. opens and the control signal ■
2 closes the electromagnetic valve 22 of the second variable stiffness means 24. Therefore, when the steering wheel is turned further, the roll rigidity of the front suspension 18 is increased and the camber angle of the front wheel 17F is controlled in the negative direction, and the roll rigidity of the rear suspension 19 is decreased and the rear wheel 17R is A positive camber angle change is encouraged. Furthermore, when the steering wheel is turned back or held, the roll stiffness of the front suspension 18 is reduced, promoting a positive camber angle change of the front wheels 17F, and the roll stiffness of the rear suspension 19 is increased. 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 to facilitate tail sliding and promote vehicle control, and when the steering wheel is turned back, the wheel camber angle is controlled to reduce tail flow. The camber angle of the wheels is controlled to promote convergence.

In this way, in this embodiment, the distribution of roll stiffness is changed between the front suspension 18 and the rear suspension 19 depending on the steering state of the vehicle, and both turning performance and convergence performance are stabilized, especially during high-speed turns. Since the camber angle of the wheels is controlled so as to improve the driving performance and steering stability of the vehicle. Furthermore, in the past, it was extremely difficult to achieve both maneuverability and stability in the area near the steering limit, but this includes the control moment when turning more and the countersteering when turning back) Since it is possible to increase the restoring moment at both times, maneuverability in the limit range, including drifting, is significantly improved.

FIG. 3.4 is a diagram showing a second embodiment of the present invention, in which fluid-filled bushings 31 are provided at two connecting portions between the suspension member 11 and the transverse link 12 of the front suspension 18, respectively. ing. Each fluid-filled bushing 31 has two fluid chambers 31a and 31b arranged on both sides of the transverse link 12 in the longitudinal direction with the connecting port 2a in between.
, 31b are filled with an incompressible fluid or the like. Also,
Both fluid-filled bushings 31 are connected to piping 32 similar to the first embodiment.
The first stiffness variable means 34 is configured together with the electromagnetic valve 33, and the first stiffness variable means 34 adjusts the compressive load and tensile load acting on the transverse link 12 while the vehicle is turning in accordance with the control signal Vl from the control means 28. On the other hand, by increasing or decreasing the rigidity of the pair of left and right fluid-filled bushings 31, the roll rigidity of the front suspension 18 can be changed. The rear suspension 19 is also provided with a second stiffness variable means (not shown) similar to the first stiffness variable means 34, and receives the control signals V, , V from the control means 28, and Since the roll rigidity distribution of the front suspension 18 and the rear suspension 19 is changed depending on the steering state of the vehicle, the same effects as in the first embodiment can be obtained.

(Effect) According to the present invention, the control means controls the operation of the first stiffness variable means and the second stiffness variable means based on the detection information from the steering state detection means, and The camber angles of the front and rear wheels are controlled by increasing the roll rigidity of one of the front and rear wheel suspension systems and decreasing the roll rigidity of the other, so that the camber angle of the front and rear wheels is controlled depending on the steering condition of the vehicle. By changing the distribution of roll stiffness between the suspension system on the rear wheel side and the rear wheel side, the camber angle can be controlled so that both retrospective performance and convergence performance are stabilized, especially when turning at high speed. As a result, the driving performance and steering stability of the vehicle can be improved.

[Brief explanation of the drawing]

Fig. 1.2 is a diagram showing a first embodiment of the wheel camber angle control device according to the present invention, Fig. 1 is a schematic configuration diagram thereof, Fig. 2 is a control flow chart of its control means, and Fig. 3.4 The figures are diagrams showing a second embodiment of the 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 the main part thereof, and Figs. This is a diagram showing the fifth
The figure is a schematic configuration diagram thereof, and FIG. 6 is a sectional view of the main part thereof. 17F...Front wheel, 17R...Rear wheel, 18...Front suspension (suspension system on the front wheel side), 19...Rear suspension (suspension on the rear wheel side) Suspension system) Mi23.34...First rigidity variable means, 24...
. . . second rigidity variable means, 25 . . . steering state detection means, 28 . . . control means.

Claims (1)

[Claims] a first rigidity variable means that is provided on the suspension system on the front wheel side and is capable of changing the roll rigidity of the suspension system; and a first rigidity variable means that is provided on the suspension system on the rear wheel side and is capable of changing the roll rigidity of the suspension system. The second variable stiffness means, the steering state detecting means for detecting the steering state of the vehicle, and the operation of the first variable stiffness means and the second variable stiffness means are controlled based on the detection information from the steering state detecting means. and control means for increasing the roll rigidity of one of the suspension systems and decreasing the roll rigidity of the other according to the steering state of the vehicle, thereby controlling the camber angles of the front wheels and the rear wheels. A wheel camber angle control device featuring: