JPH0231290Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electronically controlled suspension device that releases attitude control when lateral acceleration becomes less than a reference lateral acceleration.

An electronically controlled suspension system is being considered that improves ride comfort and handling stability by electronically controlling the damping force of a shock absorber and the spring constant of an air spring. Such an electronically controlled suspension device has a suspension with an air spring chamber for each wheel, and by opening the air supply valve, compressed air is supplied from the reserve tank to the air spring chamber, or the exhaust valve is opened. Attitude control is performed by exhausting compressed air from the air spring chamber to the exhaust pipe. In this kind of posture control,
When the steering angle of the steering wheel becomes less than the reference angle θ ₀ , some systems open a communication valve to restore the vehicle's posture, but if the steering angle of the steering wheel exceeds the reference angle θ ₀ and the vehicle stops, the vehicle is tilted. The disadvantage is that it stops at

This idea was made in view of the above points, and its purpose is to control the vehicle body posture when the lateral acceleration falls below the reference lateral acceleration in the electronically controlled suspension system that controls the vehicle body posture. The purpose of the present invention is to provide an electronically controlled suspension device that releases the suspension.

Hereinafter, an electronically controlled suspension device according to an embodiment of the invention will be described with reference to the drawings. In Figure 1, S _FR indicates a suspension unit for the right front wheel of a car, S _FL indicates a suspension unit for the left front wheel, S _RR indicates a suspension unit for the right rear wheel, and S _RL indicates a suspension unit for the left rear wheel. ing. The suspension units S _FR , S _FL , S _RR , and S _RL have main air spring chambers 11a to 11d and sub air spring chambers 12a to 12, respectively.
d, shock absorbers 13a to 13d, and a coil spring (not shown) used as an auxiliary spring. Further, 15a to 15d are switching devices for switching the damping force of the shock absorbers 13a to 13d to hard or soft. The switching devices 15a to 15d are controlled by the controller 16. In addition, 17a
-17d are bellows, respectively.

Furthermore, a compressor 18 compresses the atmospheric air sent from an air cleaner (not shown) and supplies it to the dryer 19. This dryer 19 dries the supplied compressed air using silica gel or the like. The compressed air from the dryer 19 is stored in a front wheel reserve tank 20F and a rear wheel reserve tank 20R via a pipe A, respectively.
Reference numeral 21 denotes a pressure sensor provided in the reserve tank 20F. When the internal pressure of the reserve tank 20F decreases to a set value or less, a signal from the pressure sensor 21 causes the compressor 18 to operate.
When the internal pressure of the reserve tank 20F becomes equal to or higher than the set pressure, the compressor 18 is stopped by a signal from the pressure sensor 21.

Further, the reserve tank 20F and the main air spring chamber 11a are connected to the reserve tank 20F and the main air spring chamber 11b via the air supply solenoid valve 22a.
are connected via the air supply solenoid valve 22b. Furthermore, the reserve tank 20R and the main air spring chamber 11c are connected to an air supply solenoid valve 22c.
The reserve tank 20R and the main air spring chamber 11d are connected via an air supply solenoid valve 22d. The above solenoid valves 22a to 22
d is a valve that is always closed.

Further, the compressed air in the main air spring chamber 11a passes through the exhaust solenoid valve 23a, the compressed air in the main air spring chamber 11b passes through the exhaust solenoid valve 23b, and the compressed air in the main air spring chamber 11c passes through the exhaust solenoid valve 23a. The compressed air in the main air spring chamber 11d is released to the atmosphere via the exhaust solenoid valve 23c and an exhaust pipe (not shown). The solenoid valves 23a to 23d are valves that are always closed.

Furthermore, the main air spring chamber 11a and the auxiliary air spring chamber 12a each have a spring constant switching solenoid valve 26.
The main air spring chamber 11b and the auxiliary air spring chamber 12b are connected to a spring constant switching solenoid valve 2 via a.
6b, the main air spring chamber 11c and the auxiliary air spring chamber 12c are connected to the spring constant switching solenoid valve 26c, and the main air spring chamber 11d and the auxiliary air spring chamber 12d are connected to the spring constant switching solenoid valve 26d. are connected to each other via

Furthermore, the main air spring chambers 11a and 11b are connected via a communication pipe B and a communication solenoid valve 27F,
The main air spring chambers 11c and 11d are connected via a communication pipe C and a communication solenoid valve 27R.
The communication solenoid valves 27F and 27R are valves that are always open.

By the way, the solenoid valves 22a to 22
d, 23a-23d, 26a-26d, 27F,
Opening/closing control of 27R is performed by signals from the controller 16.

Furthermore, 30 is a steering sensor that detects the steering angle of the steering wheel, 31 is a brake sensor that detects on/off of the brake, 32 is an accelerator opening sensor that detects the opening of the accelerator, and 33 is a steering sensor that detects the steering angle of the steering wheel, 33 is an accelerator opening sensor that detects the opening of the accelerator, and 33 is a steering sensor that detects the steering angle of the steering wheel. An acceleration sensor that detects acceleration, 34 a vehicle speed sensor that detects vehicle speed, 35 a front vehicle height sensor that detects the height of the front part (front wheel part) of the car, and 36 a rear part (rear wheel part) of the car.
This is a rear vehicle height sensor that detects the vehicle height of the vehicle. Signals from the sensors 30 to 36 are supplied to the controller 16.

Next, the operation of one embodiment of the invention constructed as described above will be explained. First, the gist of the present application will be explained while explaining the roll control of the vehicle body. For example, the attitude control of the vehicle body when the steering wheel is turned to the right will be explained with reference to the flowchart shown in FIG. At step S1 in FIG. 2, the vehicle speed detected by the vehicle speed sensor 34 is input to the controller 16. Furthermore, step S
In step 2, the steering wheel steering angle detected by the steering sensor 30 is input to the controller 16, and the temporal change in the steering wheel steering angle, that is, the steering wheel angular velocity is calculated. Then, in step S3, the controller 1
The map of the valve opening time versus vehicle speed vs. steering wheel angular velocity shown in FIG. 3 stored in FIG. It is determined whether the data belongs to an area in which the process is not performed. If it is determined in step S3 that the vehicle belongs to the control area, the process proceeds to step S4, where the steering direction of the steering wheel is detected based on a signal from the steering sensor 30. Then, in step S5, the steering direction of the steering wheel is determined. In this example, since the handle is turned to the right, the process proceeds to step S6, where the communication solenoid valves 27F and 27 are controlled by a control signal from the controller 16.
R is closed. Next, the air intake solenoid valves 22b and 22d for the left wheel are connected to the area shown in FIG.
The main air spring chamber 11 is opened for a predetermined time determined by
A set amount of compressed air is supplied to b and 11d. As a result, the vehicle height on the left wheel side is biased in a direction higher than before the supply. Further, the exhaust solenoid valves 23a and 23c for the right wheel are opened for a predetermined period of time determined by the region ~ in FIG. 3, and a set amount of compressed air from the main air spring chambers 11a and 11c for the right wheel is discharged. As a result, the vehicle height for the right wheel is biased in a direction lower than before the discharge. In other words, when you turn the steering wheel to the right, the vehicle height of the left wheel decreases, and the vehicle height of the right wheel is suppressed from increasing.
Keeps the vehicle level.

On the other hand, if the steering wheel is turned to the left, the process proceeds to step S7, where the communication solenoid valves 27F and 27R are closed by a control signal from the controller 16.

Next, the left wheel exhaust solenoid valve 23b
and 23d are opened for a predetermined period of time determined by areas 1 to 3 in FIG. 3, and a set amount of compressed air from the main air spring chambers 11b and 11d is discharged. At the same time, the air supply solenoid valves 23a and 23c for the right wheel are opened for a predetermined period of time defined by regions ~ in Figure 3.
A set amount of compressed air is supplied to the main air spring chambers 11a and 11c of the right wheel. In other words, when the steering wheel is turned to the left, the height of the right wheel is lowered, preventing the height of the left wheel from rising and keeping the vehicle level.

Next, after the above-described vehicle body attitude control is performed, the process advances to step S8. In this step S8,
The steering wheel steering angle θ is detected by a signal from the steering sensor 30. Further, in step S9, it is determined whether the steering wheel steering angle θ is larger than the reference angle θ ₀ . If it is determined in this step S9 that the steering wheel steering angle θ is less than or equal to the reference angle θ ₀ (for example, ±15 degrees), the process proceeds to step S10, where the communication solenoid valves 27F and 27R are opened, and the process proceeds to step S1.
Return to In other words, vehicle body attitude control is canceled.

On the other hand, if it is determined in step S9 that the steering wheel steering angle .theta. is larger than the reference angle _.theta.0 , the process proceeds to step S11, where the lateral acceleration a/g detected by the acceleration sensor 33 is read into the controller 16. Then, in step S12, the magnitude relationship between the lateral acceleration a/g and the reference lateral acceleration a ₀ /g is determined. In this step S12, if it is determined that the lateral acceleration a/g is equal to or less than the reference lateral velocity _a0 /g, the process proceeds to step S13, where the communication solenoid valve 27 is
F and 27R are opened and the main air spring chamber 11 of the front wheel is opened.
a and 11b and rear wheel main air spring chambers 11c and 11
d is communicated. On the other hand, if it is determined in step S12 that the lateral acceleration a/g is greater than the reference lateral acceleration a ₀ /g, the process returns to step S1. In other words,
The vehicle body attitude control performed in steps S6 and S7 is canceled when the steering wheel steering θ becomes less than the reference angle θ ₀ or when the lateral acceleration a/g becomes less than the reference lateral acceleration a ₀ /g.

In addition, in FIG. 3, t ₁ <t ₂ <t ₃ is set.

As detailed above, according to this invention, in the electronically controlled suspension system that controls the attitude of the vehicle, the control of the attitude of the vehicle is canceled when the lateral acceleration falls below the reference lateral acceleration. Therefore, even if the vehicle stops at a steering angle of the steering wheel or a reference angle θ ₀ or more, the vehicle body posture can be restored.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an electronically controlled suspension system according to an embodiment of the invention, FIG. 2 is a flowchart for performing attitude control, and FIG. 3 is a diagram showing vehicle speed-handle angular velocity characteristics. 11a-11d...main air spring chamber, 12a-1
2d...Sub-air spring chamber, 16...Controller,
33... Acceleration sensor.

Claims (1)

[Claims for Utility Model Registration] A suspension unit provided for each wheel and each having a fluid spring chamber, and a fluid supply capable of supplying fluid to each fluid spring chamber of each suspension unit through a supply on-off valve. means, a fluid discharge means capable of discharging fluid from each fluid spring chamber of each suspension unit via a discharge on-off valve, and fluid spring chambers of each left and right suspension unit connected to each other between the front wheels and between the rear wheels. A communication means communicating through a general control valve, a roll displacement detection means for detecting roll displacement of the vehicle body, a steering wheel angle detection means for detecting a steering wheel angle, and the communication control valve of the communication means is normally opened. This allows the fluid spring chambers of the left and right suspension units to communicate with each other between the front wheels and the rear wheels,
When the roll displacement of the vehicle body is detected by the roll displacement detection means, the communication control valve of the communication means is closed, and the supply opening/closing valve of the fluid spring chamber on the compression side of each suspension unit with respect to the roll direction of the vehicle body is closed. A set amount of fluid is supplied to the fluid spring by opening for a set time, and a set amount of fluid is discharged from the fluid spring chamber by opening the discharge on-off valve of the fluid spring chamber on the extension side for a set time. By doing so, the roll displacement of the vehicle body is suppressed, and after performing control to suppress the roll displacement, when the steering wheel angle detected by the steering wheel angle detection means becomes equal to or less than the set value, each communication of the communication means is and a roll displacement suppression control means configured to open a control valve, the suspension device comprising an acceleration detection means for detecting lateral acceleration acting on the vehicle body, the roll suppression control means configured to control the roll displacement. After the detection means detects roll displacement of the vehicle body and performs control to suppress the roll displacement, each communication control valve of the communication means is activated when the acceleration detected by the acceleration detection means becomes equal to or less than a set value. An electronically controlled suspension device configured to open.