JP3085075B2 - Roll rigidity control device for vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to controls the roll stiffness changing mechanism provided between the vehicle body and each vehicle wheel in response to a change in the driving operation that causes the vehicle body attitude change or the posture change ,
The present invention relates to a vehicle roll rigidity control device that switches the roll rigidity of a vehicle between a soft side and a hard side.

[0002]

2. Description of the Related Art Conventionally, this type of apparatus is disclosed in
As disclosed in Japanese Patent Application Laid-Open No. 8-30815, the steering angle and the vehicle speed are electrically detected, and when the voltage signal representing the detected steering angle becomes smaller than the voltage signal representing the detected vehicle speed, the steering signal is usually set to the soft side. By changing the damping force characteristic of the shock absorber to the hard side, when the steering wheel is turned greatly during low-speed driving, the damping force characteristic of the shock absorber is set to the hard side and the roll rigidity of the vehicle is set to the hard side. When the vehicle is turned at high speed, the damping force characteristics of the shock absorber are set to the hard side even if the steering wheel is turned small, and the roll rigidity of the vehicle is changed to the hard side. I try to suppress it.

[0003]

However, in the above-mentioned conventional device, the steering direction of the steering wheel is changed from left to right or right to left to make the vehicle change lanes quickly.
During slalom running, the vehicle body may roll greatly immediately after changing the steering direction of the steering wheel. That is, a centrifugal force in the opposite direction to the turning direction is acting on the vehicle body, and the direction of the centrifugal force acting on the vehicle body is also switched when the steering direction of the steering wheel is switched. Therefore, if the steering direction of the steering wheel is rapidly changed, the change in the centrifugal force acting on the vehicle body will vary greatly considering the steering direction, and the initial roll speed of the vehicle body will increase. And the body rolls greatly.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a roll rigidity control apparatus for a vehicle which improves the ride comfort and the operability of the vehicle by preventing a large roll from being generated on the vehicle body even under the above-mentioned circumstances. To provide.

In order to achieve this object, a structural feature of the present invention is to compare a physical quantity representing a change in the attitude of the vehicle body or a physical quantity representing a driving operation causing the change in the attitude with a predetermined comparison value. When the physical quantity is equal to or greater than the comparison value, in a roll rigidity control device for a vehicle that switches and controls the roll rigidity that is normally set on the soft side to the hard side, both the turning direction of the vehicle and the steering direction of the steering wheel are the same. The comparison value to be compared is set to a first predetermined value, and when the two directions do not match, the comparison value to be compared is changed to a second predetermined value smaller than the first predetermined value. I did it.

[0006]

According to the above features, according to the present invention, when the steering wheel is steered in a direction opposite to the turning direction of the vehicle, a comparison is made with the physical quantity in order to switch the roll stiffness of the vehicle from the soft side to the hard side. Since the value is changed to a small value, the roll rigidity of the vehicle in this case is more likely to be switched to the hard side than in the normal case. Therefore, even if the vehicle changes lanes quickly or runs slalom, even if the centrifugal force acting on the vehicle changes greatly,
The roll of the vehicle body is sufficiently suppressed.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 conceptually shows shock absorbers 10A to 10D as a roll rigidity changing mechanism of a vehicle according to the present invention. An electric control device 20 for controlling 10D is shown by a block diagram.

[0008] Shock absorbers 10A~10D is detail each car wheels of the left and right front wheels and left and right rear wheels are respectively arranged between the lower arm connected to the vehicle wheels (unsprung member) and vehicle body (sprung member) I have. Each shock absorber 1
0A to 10D include hydraulic cylinders 12a to 12d partitioned into upper and lower chambers by pistons 11a to 11d, respectively, and the cylinders 12a to 12d are supported by lower arms, respectively. Piston rods 13a to 13d are connected at lower ends to the pistons 11a to 11d, respectively.
The rods 13a to 13d respectively support the vehicle body at upper ends. The upper and lower chambers of the hydraulic cylinders 12a to 12d communicate with each other via electromagnetic valves 14a to 14d, and the damping force characteristics of the shock absorbers 10A to 10D become soft and hard depending on the degree of opening of the valves 14a to 14d. That is, the roll stiffness of the vehicle is set to soft and hard, respectively. When the roll stiffness of the vehicle is set to hard, the vehicle is less likely to roll than when it is set to soft. Hydraulic cylinder 1
The lower chambers 2a to 12d have piston rods 13a to 1d respectively.
Gas spring units 15a to 15d for absorbing a volume change of the upper and lower chambers due to the vertical movement of 3d are connected respectively.

The electric control device 20 includes a vehicle speed sensor 21, a steering angle sensor 22, and a lateral acceleration sensor 23. Vehicle speed sensor 21 detects the output shaft of the transmission (not shown), the rotational speed, such as the vehicle wheels, and outputs a detection signal indicative of the vehicle speed V which varies in proportion to the rotational speed. Steering angle sensor 22
Detects the rotation angle of the steering shaft (not shown), the amount of displacement of the rack bar, etc., and changes the steering wheel angle θf that changes in proportion to the rotation angle, the amount of displacement, etc. Is expressed as a negative value). The lateral acceleration sensor 23 is constituted by an acceleration sensor mounted on the vehicle body to detect the turning direction of the vehicle, and a lateral force (for example, centrifugal force) applied to the vehicle body, that is, a lateral acceleration Gy.
(A right direction is represented by positive and a left direction is represented by negative). For example, the detected lateral acceleration Gy is
It becomes positive when the vehicle turns left and negative when the vehicle turns right.

The vehicle speed sensor 21 and the steering angle sensor 22
The lateral acceleration sensor 23 is connected to the microcomputer 26 via high-pass filters 24a to 24c and low-pass filters 25a to 25c, respectively. The high-pass filters 24a to 24c and the low-pass filters 25a to 25c remove the high-frequency noise component and the DC drift component of the detection values of the sensors 21 to 23, respectively. The microcomputer 26 repeatedly executes a program corresponding to the flowchart shown in FIG. 2 every predetermined short time under the control of a built-in timer circuit. As shown in FIG. 3, the microcomputer 26 stores a first comparison value θ that changes in accordance with a change in the vehicle speed V.
A table in which v1 (solid line) and the second comparison value θv2 (dashed line) are stored is prepared. Drive circuits 27a to 27d respectively corresponding to the shock absorbers 10A to 10D are connected to the microcomputer 26,
Each of the drive circuits 27a to 27d is a microcomputer 26
In response to the control signal from the controller, the opening of each of the electromagnetic valves 14a to 14d is switched and controlled.

Next, the operation of the embodiment configured as described above will be described. When the ignition switch is turned on, the microcomputer 26 executes an initial setting process (not shown), and thereafter repeatedly executes a program including steps 100 to 134 at predetermined time intervals. In the initial setting process, the control flag CFLG indicating "1" indicating that the damping force characteristics of the shock absorbers 12a to 12d are switched to the hardware side is initially set to "0", and the hardware side is switched to the hardware side. The timer count value TCNT for measuring the switching time of is initialized to “0”.

On the other hand, in the program, detection signals representing the vehicle speed V, the steering angle θf and the lateral acceleration Gy are input from the vehicle speed sensor 21, the steering angle sensor 22 and the lateral acceleration sensor 23 in step 102, and in step 104
By differentiating the steering wheel angle θf, the steering wheel speed θv (= dθf / dt) is calculated. Next, at steps 106 and 108, the operand x is positive,
"0", when negative, "+1", "0", "-"
1 ", the steering direction γ of the steering wheel is calculated.
θ (= sign [θv]) and the turning direction γG of the vehicle (= −sign
[Gy]) is derived. In this case, the steering direction γ of the steering wheel
θ and the turning direction γG of the vehicle are both represented by “+1” in the right direction and “−1” in the left direction.

Next, at step 110, it is determined whether or not the steering direction γθ of the steering wheel and the turning direction γG of the vehicle match, and at step 112, whether the turning direction γG of the vehicle indicates “0”. Determine whether or not. If the vehicle is traveling straight or turning normally, and the steering direction γθ of the steering wheel matches the turning direction γG of the vehicle or the turning direction γG indicates that the vehicle is traveling straight, step 11 is executed.
It is determined to be “YES” in any of 0 and 112, and the program proceeds to step 118. In step 118, the first comparison value θv1 (V) is read from the table according to the vehicle speed V, and the absolute value | θv of the calculated steering speed θv is calculated.
Is compared with the read first comparison value θv1 (V).
If the absolute value | θv | of the steering speed θv is smaller than the first comparison value θv1 (V), “NO” is determined in step 118, and
At step 124, it is determined whether or not the timer count value TCNT is equal to or less than "0". The timer count value TCNT has been set to “0” by the above-described initialization processing, and also has the shock absorbers 10A to 10A as described later.
0D is switched to the hardware side and the control flag CFLG is "1"
Is not changed until it is set to “YES”.
Proceed to 128.

In step 126, the microcomputer 26 sends a control signal representing software to the drive circuit 27a.
To 27d. The drive circuits 27a to 27d store the control signal supplied this time instead of the previously stored control signal, and switch the opening of the electromagnetic valves 14a to 14d to a larger side based on the stored control signal. As a result, the damping force characteristics of the shock absorbers 10A to 10D are set to the soft side. After the processing of step 126,
At step 128, the control flag CFLG is set (maintained) to “0”, and at step 130, “NO” is determined based on the fact that the control flag CFLG is “0”, and step 13
At 4, the execution of the program is terminated. When a predetermined time elapses from the end of execution of this program, execution of the program is started again. However, the steering direction γθ of the steering wheel matches the turning direction γG of the vehicle or the turning direction γG indicates the straight traveling of the vehicle, and the steering speed θv If the absolute value | θv | is smaller than the first comparison value θv1 (V), step 10 similar to the above is performed.
2 to 112, 118, 124 to 130 and 134 are executed. Therefore, in this state, the damping force characteristics of the shock absorbers 10A to 10D are maintained on the soft side.

When the steering wheel is steered left and right, the steering direction γθ of the steering wheel coincides with the turning direction γG of the vehicle, but the absolute value | θv | of the steering speed θv is equal to the first comparison value θv1.
If (V) or more, "YES" is determined in step 118, and a control signal indicating hardware is output to the drive circuits 27a to 27d in step 120. Drive circuits 27a-2
7d stores the control signal supplied this time instead of the previously stored control signal, and switches the opening of the electromagnetic valves 14a to 14d to a smaller side based on the stored control signal. As a result, the damping force characteristics of the shock absorbers 10A to 10D are switched to the hard side. After the processing in step 120, the control flag CFLG is set in step 122.
With change to "1", it sets the timer count value TCNT to a predetermined positive value T _1.

Accordingly, the absolute value of the steering speed θv | θv |
Is smaller than the first comparison value θv1 (V),
24, the determination is “NO”, and
In step 132, the microcomputer 26 determines the timer count value TCNT every time the program is executed (every predetermined time) while maintaining the shock absorbers 10A to 10D on the hardware side. Decrease by "1". And the timer count value TCNT
Becomes "0", "YES" is determined in step 124, and the damping force characteristics of the shock absorbers 10A to 10D are returned to the soft side by the processing of step 126 described above, and the control flag CFLG is set to "0". return. As a result, when the handle is abruptly steered to the left and right, since the damping force of the shock absorber 10A~10D is controlled switched to the hard side of only the soft side predetermined time corresponding to a predetermined value T _1, the vehicle body due to the quick steering Posture change is well suppressed.

Next, when the steering wheel is steered in a direction opposite to the turning direction of the vehicle in order to make the vehicle run slalom or change lanes, immediately after the steering operation, the steering wheel calculated by the processing in step 106 is executed. Does not coincide with the turning direction γG of the vehicle calculated by the processing in step 108, and the turning direction γG is not “0”.
In both cases, “NO” is determined, and the determination process of step 114 is executed. In the determination process of step 114, the second comparison value θv2 (V) is read from the table according to the vehicle speed V, and the absolute value | θv | of the steering speed θv calculated in step 104 is read. The second comparison value θv2 (V) is compared. Also in this case, the absolute value | θv | of the steering speed θv is equal to the second comparison value θv2 (V).
If it is smaller, through the process of step 116 of determining whether the timer count value TCNT is equal to or less than “0”,
Since the program proceeds to step 126 or step 130, the damping force characteristics of the shock absorbers 10A to 10D are maintained on the soft side.

On the other hand, if the steering direction γθ of the steering wheel does not match the turning direction γG of the vehicle and the absolute value | θv | of the steering speed θv becomes equal to or greater than the second comparison value θv2 (V), the routine proceeds to step 114. If "YES" is determined, the program proceeds to step 120. Therefore, also in this case, so that the damping force of the shock absorber 10A~10D is controlled switched to the hard side of only the soft side predetermined time corresponding to a predetermined value T _1. In this case, since the second comparison value θv2 (V) is set smaller than the first comparison value θv1 (V), the steering direction γθ of the steering wheel described above and the turning direction γG of the vehicle match or the turning direction γG is Even if the absolute value | θv | of the steering wheel steering speed θv is smaller than in the case where the vehicle is traveling straight, the damping force characteristics of the shock absorbers 10A to 10D are switched to the hard side. That is,
The tendency of the damping force characteristics of the shock absorbers 10A to 10D to be switched to the harder side than during normal turning travel increases. Then, the damping force characteristics of the shock absorber 10A~10D, by the processing of steps 122,124,132 described above, is maintained by the hard side predetermined time corresponding to a predetermined value T _1.

As can be understood from the above description, in the above-described embodiment, the steering as the physical quantity representing the driving operation causing the change in the posture of the vehicle body by the processing of the steering angle sensor 22 and the step 104 (posture change detecting means). The speed θv is detected, and the absolute value | θv | of the same steering speed θv is obtained through the processing of steps 114, 118, and 120 (switching control means).
Is larger than the predetermined comparison values θv1 (V), θv2 (V), the shock absorber 10A normally set on the software side
The damping force characteristics of 10 to 10D are switched to the hardware side and controlled. Then, the turning direction of the vehicle is detected by the lateral acceleration sensor 23 and the processing of step 108 (turning direction detecting means), and the steering direction of the steering wheel is detected by the processing of step 106 (steering direction detecting means).
By the process (change means) of step 10, the steering speed θv is compared with the first comparison value θv1 (V) when the two directions match, and the steering speed θv is compared with the second comparison value θv2 ( V).

Therefore, according to the above embodiment, in order for the vehicle to make a fast lane change or to run a slalom, the turning direction of the vehicle and the steering direction of the steering wheel are reversed, and the centrifugal force acting on the vehicle body is reduced. If it changes significantly,
The damping effect of the shock absorbers 10A to 10D on the roll of the vehicle body largely acts, and the roll of the vehicle body is sufficiently suppressed.

In the above-described embodiment, the steering speed θv is adopted as a physical quantity representing a driving operation that causes a change in the posture of the vehicle body, and the damping force characteristics of the shock absorbers 10A to 10D are changed according to the magnitude of the steering speed θv. Although the steering is switched to the hardware side, the steering angle θf is adopted as the physical quantity, and the steering angle θf is compared with a predetermined comparison value in place of the processing in steps 114 and 118 to obtain a larger value of the steering angle θf. Shock absorbers 10A to 10
The damping force characteristic of D may be switched to the hard side. In addition, the stroke amount (vertical displacement amount of the vehicle body with respect to the wheels) of the shock absorbers 10A to 10D is detected as a physical amount representing a change in the posture of the vehicle body,
In place of the processing of step 118, the physical quantity is compared with a predetermined comparison value, and the shock absorber 10 is selected according to the magnitude of the physical quantity.
The damping force characteristics of A to 10D may be switched to the hardware side. In these cases, the comparison value used in step 114 is made smaller than the comparison value used in step 118, as in the above embodiment.

In the above embodiment, the lateral acceleration Gy obtained by detecting the turning direction of the vehicle by the lateral acceleration sensor 23 is used.
Instead, the steering wheel steering angle θf detected by the steering angle sensor 22, the roll angle of the vehicle body detected by the roll angle sensor, the yaw rate of the vehicle body detected by the yaw rate sensor, and each shock absorber The determination may be made based on the difference between the left and right stroke amounts detected by 10A to 10D and the difference between the vertical accelerations of the vehicle body detected by the vertical acceleration sensors at the left and right wheel positions.

Further, in the above-described embodiment, a description has been given of a case in which a variable damping force type shock absorber is used as the roll rigidity changing mechanism and the damping force characteristic is switched as the roll rigidity is switched. However, the roll rigidity changing mechanism may be a variable spring force type fluid spring formed by sealing a fluid instead of a variable spring force stabilizer or a coil spring. May be switched.
Further, the roll rigidity may be switched by changing the damping force generated in the hydraulic cylinder of the hydraulic active suspension.

[0024]

As described above, according to the present invention,
Even if the vehicle makes a fast lane change or is running in a slalom and the centrifugal force acting on the vehicle body changes greatly immediately after the steering wheel is steered in the direction opposite to the turning direction of the vehicle, the switching control means and the roll rigidity Since the mechanism sufficiently suppresses the roll of the vehicle body so as not to generate a large roll on the vehicle body, the ride comfort and the operability of the vehicle are further improved.

[Brief description of the drawings]

FIG. 1 is a schematic block diagram of a shock absorber and an electric control device for the shock absorber, showing one embodiment of the present invention.

FIG. 2 is a flowchart corresponding to a program executed by the microcomputer of FIG. 1;

FIG. 3 shows first and second programs used in the program.
9 is a graph showing a change characteristic of a comparison value with respect to a vehicle speed.

[Explanation of symbols]

10A to 10D: shock absorbers, 12a to 12d
... hydraulic cylinders, 14a to 14d ... electromagnetic valves, 20 ...
Electric control device, 21: vehicle speed sensor, 22: steering angle sensor,
23: lateral acceleration sensor, 26: microcomputer.

Claims (6)

(57) [Claims] 1. A control device provided between a wheel and a vehicle body for controlling a roll rigidity changing mechanism capable of switching a roll rigidity of the vehicle between a soft side and a hard side, the control device representing a change in the posture of the vehicle body. Attitude change detecting means for detecting a physical quantity or a physical quantity representing a driving operation that causes the attitude change,
The detected physical quantity is compared with a predetermined comparison value, and when the physical quantity becomes equal to or more than the comparison value, the roll rigidity changing mechanism is controlled to switch the roll rigidity normally set on the software side to the hard side. in roll rigidity control device for a vehicle with a switching control unit that, a turning direction detecting means for detecting a turning direction of the vehicle, the steering direction detection means for detecting the steering direction of the steering wheel, the turning direction of the detected vehicle When the two directions of the steering direction of the steering wheel coincide with each other, the comparison value compared by the switching control means is set to a first predetermined value determined in accordance with a change in the vehicle speed. The comparison value to be compared by the control means is determined according to the change in vehicle speed.
Roll stiffness control apparatus for a vehicle, characterized in that a changing means for changing from the previous SL first predetermined value to a smaller second predetermined value. 2. The roll rigidity of the vehicle body suspension device is set on the soft side or on the soft side.
Is a roll rigidity change mechanism that can be switched to the hard side and a car
Physical quantity representing body posture change or cause posture change
A body posture change detection method that detects physical quantities representing driving operations
Step, turning direction detecting means for detecting the turning direction of the vehicle,
Steering direction detecting means for detecting the steering direction of the steering wheel;
In a vehicle equipped with The turning method of the vehicle detected by the turning direction detecting means
Steering wheel detected by the steering direction detecting means
In the state where the steering directions are the same, the posture change detecting means
The detected physical quantity is determined according to the change in the vehicle speed of the vehicle.
The roll rigidity changes when the value exceeds the first predetermined value.
The vehicle body which normally controls the mechanism and is set on the software side
Switch the roll stiffness of the suspension to the hard side and detect the
Direction of turning vehicle does not match steering direction of steering wheel
Physical quantity detected by the posture change detecting means in the state of
Is determined according to a change in vehicle speed of the vehicle.
The roll when the value exceeds a second predetermined value smaller than the value
Controls the rigidity change mechanism and is usually set on the software side
Switch the roll rigidity of the vehicle suspension to the hard side Get
A vehicle row having switching control means.
Stiffness control device. 3. A body posture change detection according to claim 2.
As means, the shock constituting the vehicle body suspension device
Physics representing the change in the attitude of the vehicle body using the amount of stroke of the absorber
It is characterized by employing detection means for detecting as quantity
Roll rigidity control device for vehicles. 4. The method according to claim 2, wherein the change in posture of the vehicle body is detected.
As a means, the driving operation that causes the body posture change is displayed.
Detection that detects the steering speed of the steering wheel as a physical quantity
Roll rigidity control characterized by adopting means
apparatus. 5. A turning direction detecting means according to claim 2,
Means for detecting the lateral acceleration of the vehicle
And a roll rigidity control device for a vehicle. 6. The roll rigidity of the vehicle body suspension device is set to the soft side or
Is a roll rigidity change mechanism that can be switched to the hard side and a car
As a physical quantity representing the driving operation that causes the body posture change
Steering speed detecting means for detecting the steering speed of the steering wheel
Turning direction detecting means for detecting a turning direction of the vehicle;
Steering direction detecting means for detecting the steering direction of the rudder handle.
Equipped vehicle, The turning method of the vehicle detected by the turning direction detecting means
Steering wheel detected by the steering direction detecting means
In the state where the steering directions match, the steering speed detecting means
The detected steering speed changes according to the change in the vehicle speed of the vehicle.
The roll rigidity change occurs when the value exceeds a predetermined first predetermined value.
The vehicle suspension set on the software side by controlling the
Switch the roll rigidity of the mounting device to the hard side, and
The turning direction of the vehicle and the steering direction of the steering wheel
Steering speed detected by the steering speed detecting means in the state
Is determined according to a change in vehicle speed of the vehicle.
The roll when the value exceeds a second predetermined value smaller than the value
The rigidity changing mechanism is controlled to set the software side
Switch to switch the roll rigidity of the body suspension to the hard side
Roll rigidity of a vehicle, provided with change control means.
Sex control device.