JPH10324131A - Air suspension control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate wasteful consumption of air, and improve the operating stability by avoiding air-control of air springs in relation to the short-time change in car height, which is generated during the car travel and immediately restored. SOLUTION: The car heights are sampling-detected by a car height sensor 11 are stored in a detected car height storage-memory 17. Air-control of air springs 12A, 12B is performed by controlling solenoid valves 9A, 9B through a control unit 16. Whether a car is stopped or travels, is distinguished by detection signals from a car-speed sensor 8. When the car is stopped, the detected car heights are compared to a reference car height, and air-controlled so as to reach the reference car height. When the car is running, an average car height within a specified period of time is determined based on the stored detected car height values, and air-controlled to reach the reference car height. Thus, the need for allowing the air-control to respond to the change in the car height, which is immediately restored, is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air suspension control device for a vehicle using an air suspension as a suspension for a body frame.

[0002]

2. Description of the Related Art An air suspension uses an air spring as a chassis spring of a vehicle, and is mainly used for large trucks and the like. In trucks and the like, it is desired from the viewpoint of safe driving and efficient driving that the height (vehicle height) of the body frame is maintained at a predetermined height from the axle regardless of the magnitude of the loaded load. The predetermined height is said to be the "reference vehicle height",
The value is appropriately determined depending on the vehicle type. In a vehicle using an air spring, when the vehicle height changes, air is supplied from an air tank or air is discharged from the air spring to the atmosphere (exhaust) in order to return to the reference vehicle height.
“Air control” is performed.

FIG. 6 is a diagram showing a conventional air suspension control device. In FIG. 6, reference numeral 6 denotes an air tank;
Is a propeller shaft, 12 is an air spring, 13 is an axle, 14 is a differential, 21 is a connecting rod, 30 and 31 are air pipes, 32 is a leveling valve, 33 is a lever,
34 is a support member, and 35 is a drive wheel. The air in the air tank 6 is generated by an air compressor (not shown) driven by the engine. The axle 13 is an axle connected to a differential 14 on which the support member 3 is mounted.
4 (eg, leaf spring) is fixed. The air spring 12 is connected to the support member 34 and the body frame 20.
It is installed between the lower surface of the.

On the other hand, a leveling valve 32 is fixed to an appropriate portion of the vehicle body frame 20, and a lever 33 of the connecting rod 2 has one end fixed to the upper surface of the differential device 14.
1 is connected to the other end. The length of the connecting rod 21 is adjustable, and is adjusted so that the lever 33 is just horizontal when the vehicle height is the reference vehicle height. When the vehicle height decreases (that is, when the body frame 20 lowers relative to the differential device 14), the end of the lever 33 is pushed up by the connecting rod 21. Conversely, when the vehicle height increases, the end of the lever 33 is pulled down.

When the lever 33 is pushed up, the leveling valve 32 supplies air from the air tank 6 to the air spring 12 through the air pipe 31 to raise the body frame 20. If the lever 33 is pulled down,
The opening to the atmosphere is opened, and air is introduced into the air spring 12 through the air pipe 31 and released into the atmosphere, and the body frame 20 is lowered. Next, the operation of the leveling valve 32 will be described in detail.

FIG. 7 is a view for explaining the operation of the leveling valve. The reference numerals correspond to those in FIG.
2-2 is a valve, and 32-3 is an air passage. The air passage 32-3 has an opening that communicates with the air spring, the air tank, and the atmosphere. Valves 32-1 and 32-2 are provided in the opening that communicates with the air tank and the atmosphere. And the valves 32-1 and 32-2 are
It is opened and closed according to the movement of the lever 33.

FIGS. 7A to 7C show the following cases, respectively. (A): When the lever 33 is horizontal (= when the vehicle height is equal to the reference vehicle height) (B): When the lever 33 is pushed up (= when the vehicle height is lower than the reference vehicle height) (C) … When the lever 33 is pulled down (= when the vehicle height is higher than the reference vehicle height)

In the case (A), both valves are closed, and the air of the air spring does not change. In the case of (B), only the valve 32-1 communicating with the air tank is opened, so that the air from the air tank is supplied to the air spring. As a result, the body frame 20 is pushed up. In the case of (C), only the valve 32-2 communicating with the atmosphere is opened, so that the air from the air spring is discharged into the atmosphere. As a result, the body frame 20 is lowered.

[0009]

[Problems to be solved by the invention]

(Problem) However, in the conventional air suspension control device described above, there is a problem that the leveling valve responds to the air control one by one even if the vehicle height changes in such a short time that the vehicle is immediately restored. Was.

(Explanation of Problems) For example, when the vehicle passes over a bumpy portion of a road surface, the impact changes the vehicle height up and down.
Then, the leveling valve controls the air in response to the change, and the air in the air tank is somewhat consumed. However, when the vehicle passes over the bumps and dips on the road surface, the vehicle height change is temporary, and the vehicle height immediately returns to its original state even if air control is not performed. Therefore, the air control performed at this time is substantially useless control, and the consumed air is wasted.

[0011] Further, when traveling on a curve, the vehicle leans outward due to centrifugal force, and the vehicle height changes accordingly. Therefore, even in such a case, the air control is performed. However, even if the vehicle height changes, in this case, the vehicle returns to its original state as soon as it finishes turning the curve, and it is useless to perform air control in response to this, and waste air. Will be consumed.

As described above, in the conventional air suspension control device, even if the vehicle height changes for a short time such that the vehicle is immediately restored, the air control is performed in response to each change, so that the following inconvenience occurs. I was Because of the large amount of air consumption, it is necessary to store a large amount of air. For that purpose, a large-capacity air tank and a high-performance air compressor had to be equipped, which was expensive. Although the air compressor is driven by the engine, it often consumes air in vain, so that the fuel efficiency has deteriorated accordingly. Changing the vehicle height by performing air control while traveling on a curve may suddenly change the attitude of the vehicle while traveling on a curve, and is not preferable in terms of steering stability. An object of the present invention is to solve the above problems.

[0013]

In order to solve the above-mentioned problems, according to the present invention, air control is provided to an air spring interposed between an axle and a vehicle body frame.
In the air suspension control device that controls the vehicle height,
An electromagnetic valve connected in the middle of an air pipe for supplying air to the air spring, a vehicle height sensor, a vehicle speed sensor, and a vehicle height value detected by the vehicle height sensor which can be sampled and stored for a predetermined time. A control unit for outputting a control signal for controlling the electromagnetic valve based on the input vehicle speed detection signal and vehicle height detection signal, and determining that the vehicle is stopped based on the detected vehicle speed If so, the electromagnetic valve is controlled so that the vehicle height becomes a predetermined reference vehicle height value, and if it is determined that the vehicle is running, the average of the vehicle height detected at the predetermined time before the current time is calculated. The electromagnetic valve is controlled so that the value becomes the reference vehicle height.

Alternatively, the control unit may include an upper limit counter for counting the time when the input detected vehicle height value exceeds an upper limit of a predetermined range including a predetermined reference vehicle height, and a counter lower than the lower limit of the predetermined range. And a control signal for controlling the electromagnetic valve based on the input vehicle speed detection signal and vehicle height detection signal, and stops based on the detected vehicle speed. When it is determined that the vehicle is in the middle, the electromagnetic valve is controlled so that the vehicle height becomes a predetermined reference vehicle height value, and when it is determined that the vehicle is traveling, the time counted by the above upper limit counter is a predetermined value. When the time is longer than the time, the electromagnetic valve may be controlled so that the vehicle height becomes the reference vehicle height.

In any of the above, it is desirable that the control of the electromagnetic valve when it is determined that the vehicle is running is performed for a predetermined short period of time, and not sequentially but sequentially.

(Summary of operation to be solved) First, it is determined whether the vehicle is stopped or running based on a detection signal from a vehicle speed sensor.
If the vehicle is stopped, the vehicle height detected by the vehicle height sensor is compared with the reference vehicle height, and air control of the air spring is performed so that the reference vehicle height is obtained. However, if the vehicle is running, an average vehicle height in a predetermined period is obtained, and air control is performed so that the average vehicle height becomes a reference vehicle height, or when the vehicle height has a value outside a predetermined range over a certain period, Air control is performed to achieve the reference vehicle height. In this case, it is desirable that the air control be performed in a short time and sequentially for each air spring, not simultaneously.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, air control is not performed each time a short-term change in vehicle height immediately restores the vehicle. The change occurs when the vehicle is running, not stopped. Focusing on this, while stopping, air control is performed immediately in response to changes in vehicle height, as in the past, while running, air control is performed in a special way.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. (First Embodiment) FIG. 1 is a diagram showing an air suspension control device according to a first embodiment of the present invention. In FIG. 1, 1A and 1B are front wheels, 2A and 2B are front wheel axles, 3 is an engine, 4 is an air compressor, 5 is a transmission, 6 is an air tank, 7 is a propeller shaft, 8 is a vehicle speed sensor, and 9A and 9B are electromagnetic. Valve, 9A-
1, 9B-1 is an air opening of an electromagnetic valve, 10 is an air pipe, 11 is a vehicle height sensor, 12A and 12B are air springs, 13A and 13B are axles, 14 is a differential, 15
A and 15B are rear wheels, 16 is a control unit, 17
Is a memory for storing the detected vehicle height value.

The air springs 12A and 12B are fixed between axles 13A and 13B of the rear wheels 15A and 15B, respectively, and a body frame (not shown). When air is supplied to the air springs 12A and 12B, the body frame is raised to increase the vehicle height. Air spring 12A,
When air is exhausted (exhausted) from 12B, the vehicle body frame is lowered to lower the vehicle height.

Air is supplied from the air tank 6 in the passages in the electromagnetic valves 9A and 9B to the air springs 12A and 12A.
This is done by passing through the path to 12B. Air is exhausted from the air springs 12A, 12B in the passages in the electromagnetic valves 9A, 9B through the air release ports 9A-1, 9B.
This is done by passing through the passage to B-1. The accumulation of air in the air tank 6 is performed by driving the air compressor 4 by the engine 3. Control of the electromagnetic valves 9A and 9B is performed by the control unit 1
6 is performed. The control unit 16 generates control signals to the electromagnetic valves 9A and 9B based on detection signals from the vehicle speed sensor 8, the vehicle height sensor 11, and the like.

FIG. 5 is a diagram showing the state of attachment of the vehicle height sensor 11. The reference numerals correspond to those in FIG. 6, where 36 is a connecting rod and 37 is a lever. The vehicle height sensor 11 is fixed to an appropriate portion of the body frame 20 and its lever 37
Is connected to the axle 13 by a connecting rod 36.
The length of the connecting rod 36 is adjusted so that the lever 37 is horizontal at the reference vehicle height. When the relative height (vehicle height) of the body frame 20 with respect to the axle 13 changes, the change is transmitted to the vehicle height sensor 11 by the connecting rod 36, and the vehicle height is detected. Note that such a vehicle height sensor 11 is known.

Next, the control operation will be described. FIG.
5 is a flowchart illustrating an operation of the air suspension control device according to the first embodiment. Step 1: Detect the vehicle speed. That is, the control unit 16 reads the vehicle speed detected by the vehicle speed sensor 8. Step 2: Check the detected vehicle speed to determine whether the vehicle is stopped. That is, if the detected vehicle speed is 0 km / h, it is determined that the vehicle is stopped.

Step 3: If it is determined that the vehicle has stopped, the vehicle height is detected. That is, the vehicle height value detected by the vehicle height sensor 11 is read (the steps from this step to step 7 are the control during stopping). Step 4: Check whether the detected vehicle height is equal to a preset reference vehicle height. When the vehicle height is equal to the reference vehicle height, the control is terminated because it is a desirable state.

Step 5: If it is not equal to the reference vehicle height, it is checked whether the vehicle is lower than the reference vehicle height. Step 6: If the vehicle height is lower than the reference vehicle height, the air springs 12A, 12A
Supply air to B. That is, the control unit 16
The control valve issues a control signal to open the electromagnetic valves 9A and 9B, and closes the electromagnetic valves 9A and 9B when the detected vehicle height reaches the reference vehicle height.

Step 7: If the vehicle height is higher than the reference vehicle height,
Air is exhausted from the air springs 12A and 12B until the vehicle height decreases and reaches the reference vehicle height. That is, a control signal is issued from the control unit 16 and the electromagnetic valve 9
A, 9B opens the passage to the atmosphere opening ports 9A-1 and 9B-1, and when the detected vehicle height reaches the reference vehicle height,
Close that passage. (The above is the control when the vehicle is stopped.)

Step 8: If it is determined in step 2 that the vehicle is not stopped (running), an average vehicle height is determined.
Here, the average vehicle height is an average value of vehicle heights detected during a certain period (for example, the past one minute or ten minutes) before the present time. In the first embodiment, a memory 17 for storing a detected vehicle height value is set in the control unit 16. The detection of the vehicle height by the vehicle height sensor 11 is performed at fixed intervals (sampling time), and the detected vehicle height is stored in the detected vehicle height value storage memory 17.

FIG. 8 is a diagram for explaining a change in vehicle height and a method for obtaining an average vehicle height. The vertical axis is vehicle height, and the horizontal axis is time. H ₀ is the reference vehicle height, the solid curve is the vehicle height change, points A to K
The point indicating the vehicle height at the time of sampling the detection, t _A ~t _K time for sampling detection, T _S is the sampling time interval detected. For example, if the vehicle height is sampled and detected at time t _A , then the detected vehicle height at point A is _HA . The same applies to other points. The detected vehicle height H _{A and the} like are stored in the detected vehicle height value storage memory 17.

T _M is a fixed period set for calculating the average vehicle height. For example, when the average vehicle height is obtained at the point E (at the time t _E ), the average of the vehicle heights detected after the time t _C which is retroactive by T _M from this time is calculated. If that determine the average vehicle height at the time of the point F (at time t _F), averaging vehicle height that is detected to the time t _D after retroactive by T _M from this point.

If the capacity of the detected vehicle height storage memory 17 is N
If the vehicle height can be stored, the vehicle heights of N sampling detections can be stored. After full storage, the newly detected vehicle height is overwritten on the oldest vehicle height. Thus, the N detected values before the current time are stored. Assuming that the sampling time is t seconds, the vehicle height detected during N × t seconds before the current time can be stored. Of the stored vehicle heights, an average of a certain period before the present time is averaged to obtain an average vehicle height. Since the vehicle height sampling detection is performed at regular intervals, instead of defining the target as `` detected vehicle height for a certain period before the current time '', instead of defining the target as `` detected vehicle height for a certain number of samples before the current time, '' Even if they are defined, they are substantially the same.

Step 9: It is checked whether or not the average value is equal to the reference vehicle height. When the vehicle height is equal to the reference vehicle height, the control is terminated because it is a desirable state. Step 10: If it is not equal to the reference vehicle height, it is checked whether it is lower than the reference vehicle height. Step 11: If the vehicle height is lower than the reference vehicle height, the air springs 12A and 12B
The air is supplied only for milliseconds or one second. Even if the vehicle is farther away from the reference vehicle height, the vehicle is not returned to the reference vehicle height at once, but is gradually restored. In addition, the air is supplied not sequentially but simultaneously, for example, first to the air spring 12A, and after that, to the air spring 12B. The reason for supplying air in this way is to minimize adverse effects on steering stability, considering that sudden changes in vehicle conditions, such as vehicle height, while driving the vehicle may impair driving operation. It is. It is not always necessary to perform such control in a vehicle that does not have such a fear.

Step 12: Here, the average vehicle height is obtained again. This is because the change in vehicle height due to the air supply in step 11 is known. Step 13: It is checked whether or not the obtained average vehicle height has become equal to the reference vehicle height. If not, the process returns to step 11 to supply air again. If they are equal, the control ends.

Step 14: If it is determined in Step 10 that the average vehicle height is higher than the reference vehicle height, a predetermined time shorter than the air springs 12A and 12B (for example, 100
Exhaust air (remove air) only for milliseconds or 1 second. Even if the vehicle is farther away from the reference vehicle height, the vehicle is not returned to the reference vehicle height at once, but is gradually restored.
In addition, the air is not exhausted at the same time, but is exhausted sequentially, for example, the air is exhausted before the air spring 12A, and after that, the air is exhausted from the air spring 12B. The reason why the air is exhausted is the same as the reason described in step 11. Depending on the type of vehicle, such control need not always be performed.

Step 15: Here, the average vehicle height is also determined. This is to know the change in the vehicle height due to the air exhaust in step 14. Step 16: It is checked whether or not the obtained average vehicle height has become equal to the reference vehicle height. If not, the flow returns to step 14 to exhaust the air again. If they are equal, the control ends.

As described above, according to the present invention, it is first determined whether the vehicle is stopped or running, and the air control of the air springs 12A and 12B is different between the stopped state and the running state. That is, when the vehicle is stopped, the air control is performed according to the detected vehicle height from the vehicle height sensor 11 as it is. However, when the vehicle is running, the average vehicle height for a certain period before the present time is calculated, and air control is performed accordingly. If you do this,
Air control is not performed in response to instantaneous changes in vehicle height due to irregularities on the road surface, starting or stopping of the vehicle, etc., so that air is not wasted. In addition, if the air control during running is performed sequentially and gradually, not simultaneously on both sides, adverse effects on the steering stability can be reduced.

(Second Embodiment) In the first embodiment,
In order not to respond to a short-term change in vehicle height that immediately restores the vehicle, it is necessary to determine the average vehicle height over as long a period as possible. For that purpose, the capacity of the detected vehicle height value storage memory 17 must be increased so that many detected vehicle height values can be stored. However, if a large-capacity memory is provided, the cost increases. In addition, averaging a large number of values imposes a burden on arithmetic processing. Therefore, the air suspension control device according to the second embodiment described below is designed to reduce the cost as much as possible and to reduce the processing load.

FIG. 3 is a diagram showing an air suspension control device according to a second embodiment of the present invention. The reference numerals are the same as those in FIG.
Is a counter below the lower limit. The configuration and operation of the components having the same reference numerals as those in FIG. 1 are the same as those in FIG. The upper limit counter 18 and the lower limit counter 19 are counters set in the control unit 16. The "upper limit" and "lower limit" referred to here will be described with reference to FIG.

FIG. 9 is a diagram for explaining the change in vehicle height and the set upper and lower limits. The vertical axis, the horizontal axis, the signs, etc. are the same as those in FIG. A range (predetermined range) of a predetermined width h is set in advance up and down around the reference vehicle height value H ₀ (eg, h = 5 cm). The magnitude of ± h is set with a range allowable as an error due to the vehicle attitude as a guide.

The "upper limit" is defined as the upper limit (H ₀
+ H), and the “lower limit” is the upper limit (H ₀ −h) of this predetermined range. Upper limit counter 18
Is a counter that is incremented by one each time a vehicle height that is greater than the upper limit (H ₀ + h) is detected by the vehicle height sensor 11. The lower limit counter 19 is a counter that is incremented by one each time a vehicle height less than the lower limit (H ₀ −h) is detected by the vehicle height sensor 11. The outputs of these counters are issued when the counter value reaches a predetermined value. Only at that stage, a control operation for setting the vehicle height to the reference vehicle height is started.

That is, even if the vehicle height changes,
While the vehicle is within the predetermined range, the air control for returning to the reference vehicle height in response to the vehicle height change is not performed. Further, if the counter does not continue until the counter reaches the predetermined value even if it changes to outside the predetermined range (in other words, if the counter returns to the predetermined range in a short time), the air control is not started. In FIG. 9, from the point D to the point E, the vehicle height remains above the upper limit, but when such a state continues for a predetermined period or more (when the counter value reaches the predetermined value, The air control is started for the first time. These counters are cleared when the detected vehicle height is within the above-mentioned predetermined range.

FIG. 4 is a flowchart illustrating the operation of the air suspension control device according to the second embodiment. Steps 1 to 7 Steps 1 to 1 in the first embodiment
7, the description is omitted (that is, the control of the vehicle height while the vehicle is stopped is the same as in the first embodiment).

Step 8: The vehicle height is detected. This is the vehicle height value itself detected by the vehicle height sensor 11. Now, assume that the detected vehicle height value is H. Step 9: It is checked whether or not the detected vehicle height value H exceeds an upper limit (H ₀ + h) of a predetermined range set in advance. That is, it is checked whether or not H> H ₀ + h.

Step 10: If the value exceeds the upper limit, the counter value of the upper limit exceeding counter 18 is incremented by one. Step 11: The counter value of the upper limit exceeding counter 18 becomes
Check whether the specified value has been reached. Thus, it is possible to check whether or not the predetermined time (T ₀ ) has elapsed while the upper limit has been exceeded. Because this flowchart is played at regular time intervals, while the vehicle height exceeds the upper limit,
Since the counter value of the upper limit exceeding counter 18 increases at each time interval, when the counter value reaches a predetermined value, a predetermined time (T
₀ ) has passed.

The magnitude of the predetermined time (T ₀ ) may be different depending on the vehicle speed at the time of starting or steady running (for example, T ₀ = 30 seconds from ₀ to 50 km / h, vehicle speed). T ₀ = 100 seconds when the speed is greater than 50 km / h.If T ₀ = 30 seconds is taken as an example, the change in vehicle height due to acceleration at the start will disappear when the vehicle reaches steady running. , 30 seconds, the vehicle will normally shift to steady driving, etc.). If the counter value has not reached the predetermined value, the control is immediately terminated, and no air control is performed.

Step 12: If the counter value of the upper limit counter 18 has reached a predetermined value, the air spring 1
Air is exhausted (removed) for a predetermined time shorter than 2A and 12B (for example, 100 milliseconds or 1 second).
Even if the vehicle is farther away from the reference vehicle height, the vehicle is not returned to the reference vehicle height at once, but is gradually restored. Also,
The air is not exhausted at the same time, but is exhausted sequentially, for example, before the air spring 12A, and after that, the air is exhausted from the air spring 12B. The reason why the air is exhausted is the same as in the first embodiment (see the description of steps 11 and 14 in the flowchart of FIG. 2). Note that such control need not always be performed depending on the type of vehicle.

Step 13: Here, the vehicle height is detected. This is because the change in vehicle height due to air exhaustion in step 12 is known. Step 14: It is checked whether or not the detected vehicle height has become equal to the reference vehicle height. If not, the flow returns to step 12 to exhaust the air again. If they are equal, the control ends.

Step 15: If it is determined in Step 9 that the vehicle height does not exceed the upper limit, it is checked whether or not the vehicle height is below the lower limit. Step 16: If it is less than the lower limit, the lower limit less counter 1
The counter value of 9 is incremented by one. Step 17: The counter value of the lower limit counter 19 is
Check whether the specified value has been reached. Thus, it is possible to check whether or not a predetermined time has elapsed in a state of being lower than the lower limit. The reason is the same as described in step 11. Here, the magnitude of the predetermined value may be different depending on the vehicle speed. If the counter value has not reached the predetermined value, the control is immediately terminated, and no air control is performed.

Step 18: If the counter value of the lower limit counter 19 has reached a predetermined value, the air spring 1
Air is supplied for a predetermined time shorter than 2A and 12B (for example, 100 milliseconds or 1 second). Even if the vehicle is farther away from the reference vehicle height, the vehicle is not returned to the reference vehicle height at once, but is gradually restored. Also, the air supply
Instead, the air is sequentially exhausted, for example, by first supplying the air to the air spring 12A, and then supplying the air to the air spring 12B after that. Depending on the model,
It is not always necessary to perform such control.

Step 19: Here, the vehicle height is also detected. This is because the change in vehicle height due to the supply of air in step 18 is known. Step 20: It is checked whether or not the detected vehicle height has become equal to the reference vehicle height. If not, the flow returns to step 18 to supply air again. If they are equal, the control ends. Step 21: If it is determined in step 15 that the value is not less than the lower limit, it means that the value is within the predetermined range between the upper limit and the lower limit. Therefore, the upper limit counter 18 and the lower limit counter 19 are both cleared. I do.

According to the second embodiment, the memory capacity is smaller and the cost is lower than in the first embodiment.

[0050]

As described above, according to the air suspension control apparatus of the present invention, the air control of the air spring is performed one by one in response to a short-term change in the vehicle height which occurs during running and is immediately restored. , The following effects are obtained. (Effect of Claim 1) The air is not wasted, so that an air tank having a smaller capacity or an air compressor having a lower performance than in the past can be used in time, and the cost can be reduced. Since the air is not wasted and the time for driving the air compressor is reduced, fuel efficiency is improved.

(Effect of Claim 2) In addition to the effect of Claim 1,
It is possible to prevent an abrupt change in the attitude of the vehicle during traveling, thereby improving steering stability. (Effect of Claim 3) In addition to the effect of Claim 1, there is an effect that the memory capacity required for the control unit can be reduced and the cost can be reduced. (Effect of Claim 4) In addition to the effect of Claim 3, there is an effect that the posture of the vehicle is not suddenly changed during traveling, and steering stability is improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an air suspension control device according to a first embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the first embodiment;

FIG. 3 is a diagram showing an air suspension control device according to a second embodiment of the present invention.

FIG. 4 is a flowchart for explaining the operation of the second embodiment;

FIG. 5 is a diagram showing a mounting state of a vehicle height sensor.

FIG. 6 is a diagram showing a conventional air suspension control device.

FIG. 7 is a diagram illustrating the operation of a leveling valve.

FIG. 8 is a diagram for explaining a change in vehicle height and a method for obtaining an average vehicle height.

FIG. 9 is a diagram illustrating a change in vehicle height and upper and lower limits set.

[Explanation of symbols]

1A, 1B: front wheel, 2A, 2B: axle, 3: engine,
4 ... Air compressor, 5 ... Transmission, 6 ...
Air tank, 7 ... propeller shaft, 8 ... vehicle speed sensor,
9A, 9B: electromagnetic valve, 9A-1, 9B-1: atmosphere opening port, 10: air pipe, 11: vehicle height sensor, 12A,
12B: air spring, 13A, 13B: axle, 14
... Differential devices, 15A, 15B ... Rear wheels, 16 ... Control unit, 17 ... Memory for storing detected vehicle height value, 18 ... Counter exceeding upper limit, 19 ... Counter below lower limit, 20 ... Frame, 21 ... Connecting rod, 30, 31 ... air pipe, 32 ... leveling valve, 32-1, 32-2 ... valve, 32-3 ... air passage, 33 ... lever, 34 ... support member, 35 ... drive wheel, 36 ... connecting rod, 37 ... lever

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Bunri Mori, Inventor 4-1-1 Uedanaka, Nakahara-ku, Kawasaki City Inside Transtron Co., Ltd. (72) Yuichi Shimada 4-1-1, Uedanaka, Nakahara-ku, Kawasaki City Inside Transtron Co., Ltd.

Claims (4)

[Claims] An air suspension control device for controlling a vehicle height by controlling an air spring interposed between an axle and a vehicle body frame, comprising: an air pipe for supplying air to the air spring; An electromagnetic valve, a vehicle height sensor, a vehicle speed sensor, and a detected vehicle height value storage memory capable of sampling a vehicle height value detected by the vehicle height sensor and storing the sampled vehicle height value for a predetermined time; A control unit that outputs a control signal for controlling the electromagnetic valve based on the detected vehicle speed detection signal and the vehicle height detection signal.If it is determined that the vehicle is stopped based on the detected vehicle speed, the vehicle height is determined in advance. The electromagnetic valve is controlled to be a predetermined reference vehicle height value, and when it is determined that the vehicle is running, the average value of the vehicle height detected at the predetermined time before the present time Air suspension control system and controls the electromagnetic valve so that a reference vehicle height. 2. The air suspension control device according to claim 1, wherein the control of the electromagnetic valve when it is determined that the vehicle is running is performed for a predetermined short time, and not sequentially but sequentially. Air suspension control device. 3. An air suspension control device for controlling a vehicle height by performing air control on an air spring interposed between an axle and a vehicle body frame, wherein an air pipe for supplying air to the air spring is provided. The electromagnetic valve connected in the middle, the vehicle height sensor, the vehicle speed sensor, and the upper limit for counting the time during which the input detected vehicle height value exceeds the upper limit of a predetermined range including a predetermined reference vehicle height. A counter and a lower limit counter that counts a time that is less than the lower limit of the predetermined range, and based on the input vehicle speed detection signal and vehicle height detection signal,
And a control unit that outputs a control signal for controlling the electromagnetic valve.When it is determined that the vehicle is stopped based on the detected vehicle speed, the electromagnetic valve is controlled such that the vehicle height becomes a predetermined reference vehicle height value. When it is determined that the vehicle is traveling, when the time counted by the upper limit counter or the lower limit counter becomes equal to or longer than a predetermined time,
An air suspension control device, wherein the electromagnetic valve is controlled so that a vehicle height becomes a reference vehicle height. 4. The air suspension control device according to claim 3, wherein the control of the electromagnetic valve when it is determined that the vehicle is traveling is performed for a predetermined short time, and not sequentially but sequentially. Air suspension control device.