JP2534250B2 - Vehicle height control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an improvement in a vehicle height control device for controlling the height of a vehicle, and more particularly to a vehicle height control function for improving the vehicle height control function when the vehicle is stopped. Regarding the control device.

[Conventional technology]

As a conventional vehicle height control device, for example, one described in Japanese Patent Application Laid-Open No. 61-263818 related to the application of the present applicant is known.

This conventional device has two target vehicle height areas, a target vehicle height area for vehicle height control start determination and a target vehicle height area for vehicle height control end determination, as the target vehicle height area, and the vehicle height value is the vehicle height value. The vehicle height control is started when the vehicle deviates from the target vehicle height area for the control start judgment, and the vehicle height control is ended when the vehicle height value falls within the target vehicle height area for the vehicle height control end judgment. The vehicle height control accuracy is improved and the vehicle height control frequency is reduced.

[Problems to be solved by the invention]

However, in such a conventional vehicle height control device, the vehicle height control is started when the current vehicle height value deviates from the target vehicle height region (target vehicle height value ± dead zone) for vehicle height control start determination. Therefore, there is a problem in that the vehicle height control operation is delayed when an occupant gets on or off or loads or unloads luggage, particularly when the vehicle is stopped. Also,
Since the vehicle height control is performed even when the vehicle is jacked up when stopped, the air pressure in the air chamber drops,
Immediately after finishing the jack-up, there were problems such as the vehicle height becoming extremely low and the jack becoming stuck. In addition, the vehicle height control is performed even when the vehicle stops on a bumpy road or stops on a curb. There is a problem that high control is required, that is, unnecessary vehicle height control is performed when the vehicle is stopped on an uneven road or when the vehicle is stopped by riding on a curb.

The present invention has been made in view of such a conventional problem, and quickly and accurately performs a vehicle height control operation when an occupant gets on and off or loads and unloads a vehicle in a stopped state. When the vehicle is jacked up, stopped on a bumpy road, or picked up by a curb and stopped, unnecessary vehicle height control is not performed, so that the vehicle height control operation when stopped is accurate and accurate. It is another object of the present invention to provide a vehicle height control device that reduces the frequency of vehicle height control and improves the vehicle height control function when the vehicle is stopped.

[Means for solving problems]

Therefore, as shown in FIG. 1, a vehicle height control device of the present invention includes a suspension device having a fluid chamber capable of supplying and discharging a fluid; a pressure fluid generation device capable of generating a pressure fluid; and a vehicle height detection device. Vehicle height detecting means for determining the vehicle height value for comparing the vehicle height value detected by the vehicle height detecting means with a preset target vehicle height region; and detecting the vehicle height according to the determination result of the vehicle height determining means. And a vehicle height control means for supplying fluid from the pressure fluid generation device to the fluid chamber or discharging the fluid from the fluid chamber so that the vehicle height value thus set falls within the target vehicle height region. Vehicle stop state detecting means for detecting that the vehicle is in a stopped state; vehicle height changing speed detecting means for detecting a changing speed of vehicle height; vehicle height changing speed value detected by the vehicle height changing speed detecting means in advance Set predetermined vehicle height change speed A vehicle height change speed determination means for comparing the vehicle height change speed with a value, the vehicle stop state detection means detects that the vehicle is in a stopped state, and the vehicle height change speed determination means determines the vehicle height change speed value to be a predetermined vehicle height change. The vehicle height control means starts the vehicle height control operation when it is determined that the vehicle speed is equal to or higher than the speed value.

[Action]

The vehicle height change speed value detected by the vehicle height change speed detecting means is compared with the predetermined vehicle height change speed value by the vehicle height change speed determining means. If the vehicle stop state detection means detects that the vehicle is in a stopped state and the vehicle height change speed determination means determines that the vehicle height change speed value is greater than or equal to a predetermined vehicle height change speed value, The vehicle height control operation is started by the control means. As a result, the vehicle height control operation in the stopped state becomes accurate and accurate, and unnecessary vehicle height control operation is prevented.

Further, when the vehicle stop state detection unit does not detect that the vehicle is in the stopped state, that is, when the vehicle is traveling, the vehicle height value detected by the vehicle height detection unit is the target vehicle height region by the vehicle height determination unit. According to the result of the determination, the vehicle height control means supplies the fluid from the pressure fluid generator to the fluid chamber of the suspension device or the fluid from the fluid chamber so that the vehicle height value falls within the target vehicle height region. Discharge.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

 First, the configuration will be described.

As the working medium for vehicle height control, normal air is used in the present embodiment, but the working medium is not limited to this, and an appropriate fluid such as gas other than air or oil or other liquid is used. can do.

Referring to FIG. 2, first, the air system will be described. 1a, 1b
Is a suspension device interposed between the vehicle body (not shown) and the rear left and right wheels.
The b includes air chambers 2a and 2b and shock absorbers 3a and 3b. The air chambers 2a, 2b are formed by elastic bodies 4a, 4b made of, for example, rubber or the like that surround the space between the vehicle body and the shock absorbers 3a, 3b in a vertically expandable and contractible manner.

5 is a reservoir tank for supplying air to the air chambers 2a, 2b,
6 is a compressor for supplying air to the air chambers 2a, 2b or the reservoir tank 5, 7 is a dryer for dehumidifying the air from the compressor 6, and 8 is a check valve for preventing backflow of the reservoir tank pressure.

Reference numeral 9 is an air supply valve provided between the reservoir tank 5 and the air chambers 2a, 2b, 10a, 10b are supply / exhaust valves provided at the inlet side of each air chamber 2a, 2b, and 11 is an outlet side of the compressor 6. Is an exhaust valve provided in each valve, and each valve 9, 10a, 10b. 11 has an electromagnetic solenoid 12, 13a, 13b. 14 for opening and closing the valve.

Next, the electric system will be described. 15 is a vehicle speed sensor for detecting the vehicle speed, 16 is a vehicle height sensor for detecting the vehicle height of the rear wheels, 17 is a pressure switch for detecting the internal pressure of the reservoir tank 5, and this pressure switch The reference numeral 17 outputs a signal which is turned on when the internal pressure of the reservoir tank 5 is higher than a set value and turned off when the internal pressure is lower than the set value.

Reference numeral 18 is a battery, 19 is a relay, and 20 is a motor for driving the compressor 6.

21 is a controller, and this controller 21 includes a microcomputer and electromagnetic solenoids 12, 13a, 13b, 14
It is configured to include drive circuits 23, 24, 25 for driving the relays and a drive circuit 26 for driving the relay 19.

The microcomputer 22 is configured to include an interface circuit 27, an arithmetic processing unit 28, and a storage device 29 such as RAM and ROM. The interface circuit 27 is connected to a vehicle speed sensor 15, a vehicle height sensor 16 and a pressure switch 17. Along with
The drive circuits 23 to 26 are connected.

The arithmetic processing unit 28 reads the output signals of the vehicle speed sensor 15, the vehicle height sensor 16 and the pressure switch 17 via the interface circuit 27, and based on these, performs the arithmetic processing and other processing described later. Further, the storage device 29 stores a predetermined program necessary for executing those processes, and sequentially stores the processing result of the arithmetic processing device 28 and the like.

 Next, the operation of the above embodiment will be described.

When the ignition switch is turned on, the controller 21 is turned on, and the signals from the vehicle speed sensor 15, the vehicle height sensor 16 and the pressure switch 17 are supplied to the interface circuit 27 of the microcomputer 22.

FIG. 3 shows a procedure of processing executed by the microcomputer 22. This process is preferably executed as a timer interrupt every predetermined period Δt.

In the figure, in step, the vehicle speed value V is read from the detection signal of the vehicle speed sensor 15, and the vehicle height value h is read from the detection signal of the vehicle height sensor 16.

Next, the process proceeds to step and it is determined from the vehicle speed value V read in step whether or not the vehicle is stopped (that is, running). If V = 0, the vehicle is stopped and V ≠
If 0, it is running.

When it is determined that the vehicle is stopped in step, the process proceeds to step and the speed at which the vehicle height changes, that is, the value of the vehicle height change speed hV is calculated.

This vehicle height change speed hV is calculated by, for example, a vehicle height sensor.
The current vehicle height value and the vehicle height value before several control cycles are obtained from the 16 detection signals, and the vehicle height change speed per unit time is calculated based on the difference value. For example, the difference between the current vehicle height value and the vehicle height value 100 ms before is multiplied by 10 to calculate the vehicle height change speed per second.

At a step reads the predetermined vehicle height change rate value h _V0 which is previously stored in a predetermined storage area of the storage device 26, compares the h _V and h _V0. If h _V <h _V0 , then move to the next step, and compare h _V and −h _V0 . h _V ＞
If −h _V0 , this means that the vehicle height change speed h _V is determined to be smaller than the predetermined vehicle height change speed, and then the process proceeds to step where vehicle height control is not started, that is, vehicle height is not controlled. .

When the vehicle height is not controlled, the interface circuit 27 supplies a control signal of "L (low level or logical value" 0 ")" to the drive circuit 23 in FIG.
12 is de-energized, the air supply valve 9 is closed, the control signal “L” is supplied from the interface circuit 27 to the drive circuit 24,
Supply / discharge valve 1 with the electromagnetic solenoids 13a, 13b de-energized
0a and 10b are closed, and further, the control signal "L" is supplied from the interface circuit 27 to the drive circuit 25, the electromagnetic solenoid 14 is de-energized, and the exhaust valve 11 is closed.

Returning to FIG. 3, in steps, the vehicle height change speed h _V ≤−h
If it is _V0 , it is determined that the vehicle height change speed is greater than the predetermined vehicle height change speed, and then the process proceeds to step to start the control for increasing the vehicle height.

When controlling to increase the vehicle height, in FIG. 2, by checking whether the output signal of the pressure switch 17 is ON or OFF, the internal pressure of the reservoir tank 5 becomes lower than a preset predetermined pressure. Whether the pressure is high or not is checked, and if the internal pressure is high, the pressure is accumulated in the reservoir tank 5, and if the internal pressure is low, the compressor 6 is driven.

When the vehicle height is increased by accumulating the pressure in the reservoir tank 5, the interface circuit 27 supplies a control signal of "H (high level or logical value" 1 ")" to the drive circuit 23 to turn the electromagnetic solenoid 12 into an excited state. The air supply valve 9 is opened to supply the control signal “H” from the interface circuit 27 to the drive circuit 24 to energize the electromagnetic solenoids 13a and 13b to open the supply / exhaust valves 10a and 10b.
Supply the control signal "L" from the drive circuit 25 to the exhaust valve
Close 11 As a result, air is supplied from the reservoir tank 5 to the air chambers 2a, 2b, and the vehicle height rises.

When the vehicle height is increased by driving the compressor 6, the interface circuit 27 is used to drive the drive circuits 23, 24a, 24.
Supply the control signals "L", "H", "H", "L" to b, 25 to deactivate the electromagnetic solenoids 12, 13a, 13b, 14 in the non-excitation, excitation, excitation, non-excitation states, and supply valve. 9, supply / discharge valves 10a, 10b,
The exhaust valve 11 is closed, opened, opened, and closed, the control signal "H" is supplied from the interface circuit 27 to the drive circuit 26, and the relay 19 is turned on to drive the motor 20. In this way, the air from the compressor 6 is stored in the air chamber.
Supplied to 2a and 2b, the vehicle height rises.

Returning to FIG. 3, in steps, the vehicle height change speed h _V ≧ h _V0
If so, it is also determined that the vehicle height change speed is higher than the predetermined vehicle height change speed, and then the process proceeds to step to start the control for lowering the vehicle height.

When the control for lowering the vehicle height is performed, the interface circuit 27 to the drive circuits 23, 24a, 24b, 25 in FIG.
To the control signals "L", "H", "H", "H",
De-energize, energize, energize the electromagnetic solenoids 12, 13a, 13b, 14
This is performed by setting the air supply valve 9, the air supply / exhaust valves 10a and 10b, and the exhaust valve 11 to the closed state, the open state, the open state, and the open state. In this way, air is discharged from the air chambers 2a, 2b to the outside through the supply / discharge valves 10a, 10b and the exhaust valve 11, and the vehicle height is lowered.

Returning to FIG. 3, after the vehicle height control is not started in step, the vehicle height increase control is started in step, and the vehicle height decrease control is started in step, the process proceeds to the next step. Then, it is determined whether the vehicle height control start determination is ON. Here, the vehicle height control start determination is ON when the vehicle height increase control is started (step).
And when the vehicle height lowering control is started (step)
That the vehicle height control start determination is OFF means that the vehicle height control is not started (step).

If the vehicle height control start determination is OFF in step, nothing is done.

When the vehicle height control start determination is ON in step, it proceeds to step and determines whether or not the vehicle height value h read in step is within the target vehicle height region for ending vehicle height control. That is, the target vehicle height value h ₀ and the dead zone width Δh _B stored in advance in a predetermined storage area of the storage device 29 are read out, and if | h−h ₀ | ≦ Δh _B , the vehicle height value h ends the vehicle height control. It is determined that the vehicle height value h falls within the target vehicle height area for vehicle height control, and if | h−h ₀ |> Δh _B , the vehicle height value h is determined not to fall within the target vehicle height area for ending vehicle height control.

In the step, | h−h ₀ |> Δh _B, that is, when the vehicle height value h is not within the target vehicle height region for ending the vehicle height control, the process proceeds to the next step, and is performed before that. The existing vehicle height control operation (up control or down control) is continued. Also, in step | h−h ₀ | ≦ Δh _B ,
That is, when the vehicle height value h is within the target vehicle height region for ending the vehicle height control, the process proceeds to the next step and the vehicle height control operation is ended.

This vehicle height control ending operation is the same as the operation in the step described above.

When it is determined in step that the vehicle is traveling, the process proceeds to step, and it is determined whether the vehicle height control start determination is on, as in the above-described step. If the vehicle height control is not started, the procedure proceeds to the next step and thereafter, and the vehicle height value h read in the step.
, Is within the target vehicle height region for vehicle height control start determination. That is, the target vehicle height value h ₀ and the dead zone Δh _A for vehicle height control start determination, which are stored in advance in a predetermined storage area of the storage device 29, are read out, and in the step, whether h ≧ h ₀ + Δh _A is satisfied or not. That is, it is determined whether or not the vehicle height value is equal to or higher than the upper limit value of the target vehicle height region for vehicle height control start determination.

Here, the dead zone Δh _A of the target vehicle height area for vehicle height control start determination is set to be wider than the dead zone Δh _B of the target vehicle height area for vehicle height control end determination described above.

If h ≧ h ₀ + Δh _A in the step, the process proceeds to the next step, the value of the timer t _U is added by the control period Δt, and if h <h ₀ + Δh _A in the step, the process proceeds to the next step. After that, the value of the timer t _U is cleared to 0.

Step or after that, the process proceeds to step to determine whether or not the vehicle height value h is equal to or lower than the lower limit value of the target vehicle height region for vehicle height control start determination, that is, whether h ≦ h ₀ −Δh _A. judge.

If h ≦ h ₀ −Δh _A in the step, the process proceeds to the next step, the value of the timer t _D is added by the control period Δt, and if h> h ₀ −Δh _A in the step, then At the step, the value of the timer t _D is cleared to 0.

After or after the step, the process proceeds to the step, and it is determined whether or not the value of the timer t _U is equal to or larger than the predetermined value T _U. t _U <
If it is T _U , go to the next step and set timer T _D
Value determines whether (the value of this T _D equal to or. The value of the T _U) predetermined value T _D is greater than or equal.

If t _D <T _D in the step, the process proceeds to the next step and the vehicle height control is not started. When this vehicle height control is not started, it is the same as the case of the steps described above.

If t _D ≧ T _D in the step, the process proceeds to the next step and the vehicle height increase control is started. This vehicle height increase control is the same as in the case of the steps described above.

If t _U ≧ T _U at the step, the process proceeds to the next step and the vehicle height lowering control is started. This vehicle height lowering control is the same as in the case of the steps described above.

According to the processes of steps 1 to 3 described above, when the vehicle height value h becomes higher than the target vehicle height region for vehicle height control start determination, this is determined in step, and if the state continues, the value of the timer t _U is added in step. Continue
After continuing for a predetermined time T _U or more, vehicle height lowering control is started in step.

Similarly, when the vehicle height value h becomes lower than the target vehicle height region for vehicle height control start determination, this is determined in the step, and if the state continues, the timer t _D is determined in the step.
If the value of is added and continues for a predetermined time T _D (= T _U may be used) or more, vehicle height increase control is started in step.

In this way, when the vehicle height increase control is started in the step, and when the vehicle height decrease control is started in the step, the vehicle height control start determination is turned on in the step, and therefore the processes of steps 1 to 3 are executed next. Then, as described above, the vehicle height control operation is continued until the vehicle height value h falls within the target vehicle height region for the vehicle height control end determination.

FIG. 4 shows, as a first specific example of the vehicle height control operation, a case where an occupant gets off the vehicle while the vehicle is stopped.

In the figure, the occupant gets off at time t ₁ when the vehicle is stopped, and therefore the vehicle height value h increases.

In the conventional apparatus, since the time t ₃ vehicle height value h becomes higher than the vehicle height control starting upper limit of the target vehicle height region for determining (h ₀ + Δh _A), after the lapse of the time t ₃ for a predetermined time T _U Time of day
At t ₄ , the vehicle height control start judgment was turned on, and the control for lowering the vehicle height was started.

On the other hand, in the present invention, when the occupant gets off at time t ₁ and the vehicle height value h increases, the vehicle height change speed value h _V becomes higher than the predetermined vehicle height at time t ₂ earlier than time t _3. Change speed value h _V0
As described above, the vehicle height control start determination is turned on and the control for lowering the vehicle height is started. Therefore, according to the present invention, the vehicle height can be controlled more quickly and accurately than the conventional device.

FIG. 5 shows, as a second specific example of the vehicle height control operation, a case where the jack-up is performed while the vehicle is stopped.

In the figure, when the jack-up is started at time t ₁ when the vehicle is stopped, the vehicle height value h gradually increases.

In the conventional apparatus, when the time t ₂ vehicle height value h becomes higher than the vehicle height control starting target vehicle height region upper limit for judgment (h ₀ + Δh _A), after the lapse of the time t ₂ for a predetermined time T _U Time t ₃
Then, the vehicle height control start determination is turned on, and the vehicle height is lowered. Since the vehicle height does not decrease during jacking up, the air pressure in the air chambers 2a, 2b drops, and immediately after the jacking up, the vehicle height becomes extremely low, and the jack cannot be pulled out. It was a thing.

On the other hand, in the present invention, the vehicle height change speed value h _V during jacking up does not exceed the predetermined vehicle height change speed value h _V0 (according to experiments by the inventors, the vehicle height change speed value during jack up the value h _V has been confirmed that does not exceed a predetermined vehicle height change rate value h _V0.), control vehicle height control start determination lowers the a vehicle height remains off is not performed. Therefore, in the present invention, unnecessary vehicle height control is not performed during jacking up, the vehicle height control operation is accurate, and the frequency of vehicle height control is reduced.

FIG. 6 shows, as a third specific example of the vehicle height control operation, a case where the vehicle is stopped by riding on a curb when traveling at an extremely low speed.

In the figure, the vehicle speed is gradually reduced from during low speed traveling, the vehicle speed value h is gradually lowered by riding on a curb at time t ₁ during extremely low speed traveling, and the vehicle is stopped at time t ₃ .

In the conventional device, since the vehicle speed value h becomes lower than the lower limit value (h ₀ −Δh _A ) of the target vehicle height region for vehicle height control start determination at time t ₂ after riding on the curb at time t ₁ , from t ₂ a predetermined time T _D by the elapsed time t ₄ to the vehicle height control start judgment after is turned on, the control to increase the vehicle height from being started. Therefore, when the vehicle is stopped again on a flat road or when the vehicle starts to travel, the vehicle height is greatly inclined, and the vehicle height control is required again.

On the other hand, in the present invention, even if the vehicle rides on the curb at time t ₁ and the vehicle speed value h becomes lower than the lower limit value of the target vehicle height region for vehicle height control start determination at time t ₂ , it is extremely low speed. because traveling Nevertheless, not detected vehicle speed change rate value h _V, therefore, the time t ₃ before the vehicle is running the vehicle height control start judgment is not turned on. Then, after the vehicle stops at time t ₃ , the vehicle speed change speed value h _V is detected, but
Since the value is almost 0, the vehicle height control start determination is not turned on even after the time t _{3 when the} vehicle is stopped, and the control for increasing the vehicle height is not performed. Therefore, in the present invention, unnecessary vehicle height control is not performed, the vehicle height control operation at the time of riding on the curb becomes accurate, and the frequency of vehicle height control is reduced.

In the above-described embodiment, the one using normal air as the working fluid is illustrated, but as described above, the present invention is not limited to this, and gas other than air, oil or other liquid, etc. may be used as appropriate. Fluids can be used.

Further, although the vehicle position control is performed for the rear two wheel positions as the wheel position for executing the vehicle height control, the present invention is not limited to this, and the front two wheel positions only or all four wheel positions are particularly limited. There is no. Further, the vehicle height control of the plurality of wheel positions may be performed independently of each other, or may be performed simultaneously for all the wheel positions.

Further, in the above-described embodiment, an example is shown in which the vehicle height is controlled so that the vehicle height falls within the target vehicle height area even while the vehicle is running. First of all, the vehicle height adjustment during traveling is not always necessary, and the present invention is of course applicable to such an apparatus that does not perform vehicle height adjustment during traveling.

Further, as the target vehicle height area, an example in which two kinds of target vehicle height areas for vehicle height control start determination and vehicle height control end determination are used has been exemplified. It is also applicable to those using the target vehicle height range.

Further, in the flowchart of FIG. 3, in step after determining that the vehicle height lowering control at step after it is determined that h _V ≧ h _V0, and in step a h _V ≦ -h _V0 in step Although the vehicle height increase control is started immediately after the determination, a minute delay time may be set in order to prevent malfunction due to noise detection of the vehicle height sensor 16.

In addition, although the vehicle height control is started only when the vehicle speed change speed value becomes equal to or higher than the predetermined vehicle height change speed value when the vehicle is stopped, when the vehicle is stopped, in addition to this, the vehicle speed value is determined to be the vehicle height control start judgment. The vehicle height control may be started when the vehicle deviates from the target vehicle height range for the vehicle.

In FIGS. 1 to 3, the vehicle height sensor 16 is a concrete example of the vehicle height detecting means, the steps of and are the concrete examples of the vehicle height determining means, and the vehicle speed sensor 15 and the processing of the step stop. A specific example of the state detection means, a specific example of the vehicle height change speed detection means by the vehicle height sensor 16 and the processing of steps, the step and the processing is a specific example of the vehicle height change speed determination means, the electromagnetic solenoid 12, Air supply valve 9 having 13a, 13b, 14 supply / discharge valve 10a, 10b, exhaust valve 11, relay 1
9 and the drive circuits 23 to 26 and the processes of steps, and, and, the specific example of the vehicle height control means, and the reservoir tank 5, the compressor 6 and the motor 20 are specific examples of the pressure fluid generator.

Further, although the one configured by using the microcomputer as the controller is shown, instead of this, an addition circuit, a subtraction circuit, a multiplication circuit, a division circuit, a command value setting circuit,
It is also possible to configure the controller by combining electronic circuits such as a comparison circuit, a logic circuit, and a timer circuit.

〔The invention's effect〕

As described above, the vehicle height control device of the present invention includes a vehicle stop state detecting means for detecting that the vehicle is in a stopped state; a vehicle height change speed detecting means for detecting a vehicle height change speed; A vehicle height change speed determination means for comparing and comparing the vehicle height change speed value detected by the high change speed detection means with a preset predetermined vehicle height change speed value, and the vehicle is stopped by the vehicle stop state detection means. When it is detected that the vehicle height change speed is determined to be greater than or equal to the predetermined vehicle height change speed value by the vehicle height change speed determination means, the vehicle height control means starts the vehicle height control operation. Therefore, in the state where the vehicle is stopped, the vehicle height control operation when the occupant gets on and off or loads and unloads luggage is performed quickly and accurately, and when the vehicle is jacked up, when the vehicle is stopped on the uneven road, Or Unnecessary vehicle height control is not performed when the vehicle is stopped by riding on a stone. Furthermore, it is possible to easily distinguish between the case where vehicle height control is required when stopped and the case where vehicle height control is not required. It is possible to obtain the effect that the vehicle height control is accurate and accurate, the frequency of the vehicle height control is reduced, and the vehicle height control function when the vehicle is stopped is generally improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing a basic configuration of a vehicle height control device of the invention, FIG. 2 is a configuration diagram of an embodiment of the invention, and FIG. 3 is a flow chart showing a procedure of processing executed in a microcomputer, FIG. 4 is a time chart showing a first specific example of the operation of the above embodiment, FIG. 5 is a time chart showing a second specific example of the operation of the above embodiment, and FIG. 6 is a third operation of the above embodiment. It is a time chart which shows a specific example. 1a, 1b ... Suspension device, 2a, 2b ... Air chamber, 5 ...
... Reservoir tank, 6 ... Compressor, 9 ... Air supply valve, 10a, 10b ... Supply / exhaust valve, 11 ... Exhaust valve, 15
…… Vehicle speed sensor, 16 …… Vehicle height sensor, 17 …… Pressure switch, 20 …… Motor, 21 …… Controller, 22 …… Microcomputer, 23 to 26 …… Drive circuit, 27 …… Interface circuit, 28… ... arithmetic processing unit, 29 ... storage device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Masatsugu Yokote, 2 Takara-cho, Kanagawa-ku, Yokohama-shi Nissan Motor Co., Ltd. (72) Junsuke Kuroki, 2 Takara-cho, Kanagawa-ku, Yokohama-shi Nissan Motor Co., Ltd. (72) Invention Author Sekiguchi Tomora 1115-5 Kamiogino, Atsugi-shi (72) Inventor Masanori Kanda 1303-2 Asamizodai, Sagamihara-shi

Claims (1)

(57) [Claims] 1. A suspension device having a fluid chamber capable of supplying and discharging a fluid; a pressure fluid generating device capable of generating a pressure fluid; a vehicle height detecting means for detecting a vehicle height; and a vehicle height detecting means for detecting the vehicle height. Vehicle height determination means for comparing the determined vehicle height value with a preset target vehicle height area; and the detected vehicle height value falls within the target vehicle height area according to the determination result of the vehicle height determination means. And a vehicle height control means for supplying fluid to the fluid chamber from the pressure fluid generation device or discharging fluid from the fluid chamber, the vehicle height control device detects that the vehicle is stopped. Vehicle stop state detection means; vehicle height change speed detection means for detecting vehicle height change speed; vehicle height change speed value detected by the vehicle height change speed detection means and preset vehicle height change speed value Vehicle speed change speed judgment The vehicle stop state detecting means detects that the vehicle is in a stopped state, and the vehicle height change speed determining means determines that the vehicle height change speed value is equal to or higher than a predetermined vehicle height change speed value. The vehicle height control device is characterized in that the vehicle height control means starts a vehicle height control operation.