JPH0231282Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an electronically controlled suspension device that prevents roll (rolling) of a vehicle body.

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. In automobiles equipped with such electronically controlled suspension devices, it is desired to prevent the occurrence of rolling of the automobile and improve riding comfort and steering stability.

Therefore, a suspension unit each having a fluid spring chamber is provided for each wheel, and fluid is supplied to the fluid spring chamber on the compression side of each suspension unit in order to reduce body roll when the steering wheel angular velocity satisfies the set conditions. At the same time, it is conceivable to control the fluid to be discharged from the fluid spring chamber on the extension side. By the way, one possible starting condition for the above-mentioned roll control is to start when the steering wheel angular velocity is high, but in reality, the steering wheel angular velocity is, for example,
When it is very fast such as 300deg/sec or more,
Since the actual steering wheel angle is small (in other words, it is not possible to make a large steering wheel), performing roll control will result in an unnatural result, and if the steering wheel angular velocity is very fast, the actual roll control will not be effective. Since changes in the posture of the vehicle body cannot be followed, there is a risk that changes in the posture of the vehicle body will become unnatural.

This idea was made in view of the above points,
The purpose is to provide an electronically controlled suspension device that prevents vehicle body roll and improves safety by discontinuing vehicle body attitude control when the steering wheel angular velocity exceeds a certain level.

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

By the way, the above 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
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 θ〓 _H
is calculated. Then, proceed to step S3,
_{The steering wheel angular velocity θ〓 HO (} for example,
300deg/sec). This step S
If it is determined in step S3 that θ〓 _H > θ〓 _HO , the process advances to step S4. In this step S4, control signals are output from the controller 16 to the switching devices 15a to 15d and the spring constant switching solenoid valves 26a to 26d, and the shock absorbers 13a to 13d
The damping force of 13d is switched to hard, and the spring constant of the air spring is set to hard. Then, the process returns to step S1. In other words, when θ〓 _H > θ〓 _HO , vehicle body attitude control is not performed. On the other hand, if it is determined in step S3 that " _θ〓H < _θ〓HO ", the process advances to step S5. In this step S5, based on the vehicle speed and steering wheel angular velocity, the map of the valve opening time for the vehicle speed-steering wheel angular velocity shown in FIG. It is determined whether the object belongs to a dead zone area (an area where posture control is not performed) or a dead zone area (an area where attitude control is not performed). If it is determined in step S5 that the vehicle belongs to the control area, the process proceeds to step S6, where the steering direction of the steering wheel is detected based on the signal from the steering sensor 30. Then, in step S7, 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 S8, where the communication solenoid valves 27F and 27R are closed by a control signal from the controller 16. Next, the air supply solenoid valves 22b and 22d for the left wheel are opened for a predetermined period of time determined by regions 1 to 3 in FIG. 3, and compressed air is supplied to the main air spring chambers 11b and 11d. This raises the vehicle height for the left wheel. moreover,
Exhaust solenoid valves 23a and 23 for right wheel
C is opened for a predetermined period of time defined by the area ~ in Figure 3, and the main air spring chambers 11a and 11 for the right wheel are
The compressed air at c is released to the atmosphere. This results in
The vehicle height for the right wheel can be lowered. In other words, when the steering wheel is turned to the right, the height of the left wheel is lowered, preventing the height of the right wheel from rising and keeping the vehicle level.

On the other hand, if the steering wheel is turned to the left, the process proceeds to step S9, 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 defined in areas 1 to 3 in FIG. 3, and the compressed air in the main air spring chambers 11b and 11d is exhausted. Further, the air supply solenoid valves 23a and 23c for the right wheel are opened for a predetermined time defined by regions 1 to 3 in FIG. 3, and compressed air is supplied to the main air spring chambers 11a and 11c for 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 S10. In step S10, the steering wheel steering angle θ is detected based on the signal from the steering sensor 30. Further, in step S11, it is determined whether the steering wheel steering angle θ is larger than the reference angle θ ₀ . If it is determined in step S11 that the steering wheel steering angle θ is less than the reference angle θ ₀ (for example, ±15 degrees), the process proceeds to step S12, where the communication solenoid valves 27F and 27R are opened, and the process returns to step S1. In other words, vehicle body attitude control is canceled.

On the other hand, if it is determined in step S11 that the steering wheel steering angle _.theta. is larger than the reference angle .theta..sub.0, the process proceeds to step S11, where the vehicle speed V detected by the vehicle speed sensor 34 is read into the controller 16. Then, in step S14, the vehicle speed V and the reference speed are determined.
The magnitude relationship with V ₀ (for example, 20 Km/h) is determined. If it is determined in this step S14 that the vehicle speed V is less than or equal to the reference speed _V0 , the process proceeds to step S1.
Proceed to step 5 and connect the communication solenoid valves 27F and 2.
7R is opened and the main air spring chambers 11a and 11 of the front wheels are opened.
b and rear wheel main air spring chambers 11c and 11d are communicated with each other. On the other hand, if it is determined in step S14 that the vehicle speed V is greater than the reference speed _V0 , the process returns to step S1. In other words, the above step S8
The vehicle body attitude control performed in S9 is canceled when the steering wheel steering angle θ becomes less than the reference angle θ ₀ or when the vehicle speed becomes less than the reference speed V ₀ .

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

As detailed above, it is possible to effectively reduce the roll of the vehicle body that occurs when the steering wheel is steered, and furthermore, since the vehicle body attitude control is not performed when the steering wheel angular velocity is above a certain level, the steering wheel angular velocity is It is possible to provide an electronically controlled suspension device that can prevent unnatural changes in the vehicle body posture by controlling the vehicle body posture when the change in the vehicle body posture is large.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an electronically controlled suspension device showing an embodiment of this invention, FIG. 2 is a flowchart showing the operation, and FIG. 3 is a diagram showing vehicle speed-steering wheel angular velocity characteristics. 11a-11d...main air spring chamber, 12a-1
2d...Sub-air spring chamber, 16...Controller,
20F, 20R... Reserve tank.

Claims (1)

[Scope of utility model registration request] A suspension unit provided for each wheel and each having a fluid spring chamber; a fluid supply means capable of supplying fluid to each fluid spring chamber of each suspension unit via a supply on-off valve; A fluid discharge means capable of discharging fluid from each fluid spring chamber via a respective discharge on-off valve, a handle angular velocity detection means for detecting the angular velocity of the steering wheel steering angle, and an angular velocity detected by the above-mentioned handle angular velocity satisfies setting conditions. In order to reduce roll of the vehicle body, each of the supply on-off valves and discharge valves are arranged so that fluid is supplied to the fluid spring chamber on the compression side of each suspension unit and fluid is discharged from the fluid spring chamber on the extension side. and a controller for controlling an on-off valve for the vehicle, the controller prohibits the vehicle body posture control for reducing roll when the steering wheel angular velocity detected by the steering wheel angular velocity detecting means is equal to or higher than the reference angular velocity. An electronically controlled suspension device comprising means.