JPH11310022A - Vehicle load state judging device, vehicle state detecting device and vehicle height adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately judge the load state of a vehicle at a low cost even for a suspension arranged with a spring and an actuator in parallel by judging the load state with a value based on the vehicle height detected by a vehicle height detecting means and a value based on the internal pressure of the actuator detected by a pressure detecting means. SOLUTION: A microcomputer 30 repeatedly implements load state judgment, vehicle state detection and abnormal state recovery programs at each prescribed short period and controls the feed and discharge of a hydraulic fluid to hydraulic cylinders 11a-11d. Vehicle height sensors 32a-32d and an oil pressure sensor 34 are connected to the microcomputer 30. The vehicle height sensors 32a-32d convert the vertical movements of the lower arms 12a-12d of individual wheels into rotations of shafts and detect the electromotive force as voltage signals proportional to the rotation angles of the shafts. The pressure sensor 34 detects the oil pressure with a semiconductor strain gauge on a silicon chip and detects it as the voltage signal proportional to the oil pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load state discriminating device for discriminating a load condition applied to each wheel of a vehicle, a vehicle condition detecting device for detecting a condition of the vehicle such as a loading condition and a traveling road surface, and a vehicle height of the vehicle. The present invention relates to a vehicle height adjusting device for adjusting.

[0002]

2. Description of the Related Art Conventionally, for example, see Japanese Patent Application Laid-Open No. 62-2940.
As disclosed in FIG. 9, the dynamic pressure in the absorber 1 is detected by the pressure detecting means 2, a stroke is determined from the amount, and the load is detected by multiplying the stroke with the spring constant of the load detecting spring 3. Detection devices are known.

[0003]

However, in the above-described conventional load detecting device, the detected pressure value and the stroke correspond one-to-one, that is, the detected pressure value and the load also correspond one-to-one. It will be. In other words, the load on the absorber of each wheel is obtained only from the detected pressure value detected by the pressure detecting means, and the vehicle height at the pressure detection position at that time is not considered.
Such a load detection method that ignores the vehicle height and performs only on the basis of the detected pressure, for example, a suspension in which a spring and an actuator for adjusting the vehicle height (absorber in the above-described conventional example) are arranged in parallel. When the vehicle height is changed, accurate load detection cannot be performed due to a change in the elastic force of the spring. For example, when the vehicle load is not changed and the vehicle height is increased,
The elastic force of the spring supporting the vehicle load decreases, and the actuator pressure increases accordingly. At this time, in the above-described conventional load detection method, the load is regarded as increased, and contradiction occurs with the actual load of the vehicle.

Therefore, when trying to determine the load state using the load value detected by the load detecting means as described above, when the load state is such that the internal pressure of the actuator (absorber) is actually suitable for the actual vehicle height. Even if there is a problem, a problem such as being determined as an abnormal load state occurs. That is, according to the conventional method of detecting the load only by the pressure to the absorber, for example, when the spring and the absorber are arranged in parallel, the normal internal pressure of the absorber corresponding to the current vehicle height is used. There is a problem that it cannot be accurately determined whether or not there is, that is, whether or not the load state is normal.

In order to obtain an accurate load on each wheel (a value taking into account the vehicle height at the wheel), a load sensor using a resistance wire strain gauge incorporated in a Wheatstone bridge as a load detecting device. If the absolute load is detected by disposing the sensor at a position where the influence of a spring or the like does not affect, the above problem does not occur, but such a load detecting device is expensive.

The present invention has been made in view of such problems, and an object of the present invention is to determine a load on the basis of a vehicle height and an internal pressure of an actuator. It is another object of the present invention to accurately determine the load state of a vehicle by an inexpensive method even in a suspension in which are arranged in parallel.

[0007]

In order to achieve the above object, the present invention is directed to a vehicle height detecting means for detecting a value based on a vehicle height, and a vehicle height detecting means for detecting a value based on the vehicle height. A plurality of actuators provided to increase and decrease the vehicle height at each wheel position by a fluid supplied and discharged; and pressure detection means for detecting a value based on an internal pressure of the actuator, wherein the pressure is detected by the vehicle height detection means. The load state of the vehicle is determined based on the value based on the vehicle height and the value based on the internal pressure of the actuator detected by the pressure detecting means.

According to a second aspect of the present invention, there is provided a vehicle height detecting means for detecting a value based on the vehicle height, and a vehicle height at each wheel position is determined by a fluid provided and discharged between a plurality of wheels and the vehicle body. A plurality of actuators capable of increasing and decreasing, a pressure detecting means for detecting a value based on an internal pressure of the actuator, a value based on a vehicle height detected by the vehicle height detecting means and an inside of the actuator detected by the pressure detecting means A load state determining means for determining a load state based on a value based on pressure; at least one of the vehicle height detecting means and the pressure detecting means detecting a vehicle height or a pressure at a plurality of wheel positions of the vehicle; And detecting a vehicle state from the load state determination result.

A third aspect of the present invention provides a plurality of actuators provided between a plurality of wheels and a vehicle body and capable of increasing and decreasing the vehicle height at each wheel position by a fluid supplied and exhausted,
A fluid supply / discharge means for supplying and discharging fluid to and from the actuator, a pressure detection means for detecting a value based on an internal pressure of the actuator, a vehicle height detection means for detecting a value based on a vehicle height, and a predetermined target Control means for controlling the fluid supply / discharge means so as to eliminate a deviation of a value based on the detected vehicle height with respect to the vehicle height, wherein the vehicle height adjustment means and the pressure detection means At least one of the sensors detects a vehicle height or a pressure at a plurality of wheel positions of the vehicle, and the control unit detects a value based on the vehicle height detected by the vehicle height detection unit and the pressure detected by the pressure detection unit. A load state discriminating unit for discriminating a normal / abnormal load state of a plurality of wheel positions based on a value based on the pressure inside the actuator; Characterized in that to control the fluid supply and discharge means so as to shift the load state to a normal state of the wheel position in the abnormal state when it is determined that the abnormal state.

[0010]

(1) In the load state discriminating apparatus according to the first aspect of the invention, the value based on the vehicle height detected by the vehicle height detecting means and the internal pressure of the actuator detected by the pressure detecting means. The load state of the vehicle is determined based on the value based on. Therefore, by determining whether or not the vehicle is in a state based on the vehicle height-pressure characteristic at the time of vehicle design in which the influence of a spring or the like is taken into consideration at the time of the determination, the load state of the vehicle is reduced. It can be accurately determined by an inexpensive method without using a sensor.

(2) In the vehicle state detecting apparatus according to the second aspect of the present invention, first, the load state determining means detects the value based on the vehicle height detected by the vehicle height detecting means and the pressure detecting means detects the value based on the vehicle height. The load state is determined using the value based on the internal pressure of the actuator. Here, at least one of the vehicle height detecting means and the pressure detecting means detects a vehicle height or a pressure at a plurality of wheel positions of the vehicle, so that the load state at the plurality of wheel positions of the vehicle can be determined. The vehicle state such as the loaded load and the traveling road surface can be detected from the determined positional relationship of the vehicle.

(3) In the vehicle height adjusting apparatus according to the third aspect of the present invention, the value based on the vehicle height detected by the vehicle height detecting means by the load state determining means and the pressure detected by the pressure detecting means. Using a value based on the pressure inside the actuator, normal / abnormal of the load state of a plurality of wheel positions is determined,
When the load state is determined to be abnormal, the fluid supply / discharge means is controlled so that the load state at the wheel position in the abnormal state is shifted to the normal state. Therefore, by determining whether or not the load state of the plurality of wheel positions of the vehicle is in a region permitted for the vehicle height-pressure characteristic at the time of designing the vehicle in consideration of the influence of the spring or the like, the plurality of vehicle positions are determined. The normal or abnormal load condition at the wheel position can be accurately determined by an inexpensive method without using a load sensor. According to the discrimination result, in the case of a control abnormality in which the vehicle height at the wheel position of interest is unnecessarily high or low pressure, the fluid supply / discharge means to the actuator at the wheel position in the abnormal state is controlled. As a result, the load state of the wheel position in the abnormal state is shifted to the normal state, so that the system can be protected, and the change in vehicle height when the cause of the abnormality is removed by loading or unloading the load from outside the vehicle may increase. It is prevented and the fail-safe property is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows the overall configuration of a vehicle height adjustment device having a load discrimination device and a vehicle state detection device according to one embodiment of the present invention.

This vehicle height adjusting device includes left and right front wheels W1, W2.
And a hydraulic cylinder 11 constituting an actuator for changing the vehicle height at each wheel position of the left and right rear wheels W3 and W4.
a to 11d. Hydraulic cylinders 11a to 11d
Are lower arms 12a-1 connected to the respective wheels W1-W4.
The piston rods 13a to 13d are connected to the vehicle body 2d at the lower ends, and the upper ends thereof are fixed to the vehicle body 10 from the upper end surface.
d is protruding. Hydraulic oil is supplied to and discharged from the hydraulic cylinders 11a to 11d through oil passages P1 to P4, and the vehicle height at each wheel position is increased or decreased by the supply and discharge of the hydraulic oil. .

Coil springs 14a to 14d are interposed between the hydraulic cylinders 11a to 11d and the vehicle body 10, and variable orifices 15a are provided in the oil passages P1 to P4.
To 15d are interposed, and the cylinders 11a to 11d
Has a function as a shock absorber that cooperates with the coil springs 14a to 14d and the variable orifices 15a to 15d to support the vehicle body 10 with respect to the wheels W1 to W4 and to attenuate the vibration of the vehicle body 10. The variable orifices 15a to 15d are electrically controlled to change the orifice opening. However, since they are not directly related to the present invention, the control of the orifice opening will not be described.

The ends of the oil passages P1 and P2 and the oil passages P3 and P4 opposite to the hydraulic cylinders 11a to 11d are connected to each other, and supply and discharge of hydraulic oil to and from the hydraulic cylinders 11a and 11b are performed through the oil passages P1 and P2. The supply and discharge of hydraulic oil to and from the hydraulic cylinders 11c and 11d are performed via oil passages P3 and P4. Each of the oil passages P1 to P4 has a gate valve 17a composed of an electromagnetic switching valve.
17d are interposed respectively, and these gate valves 17a to 17d are in a conductive state in the figure when not energized, and are switched to a non-conductive state when energized.

The hydraulic supply / discharge device includes a hydraulic pump 22 driven by an electric motor 21. The pump 22 pumps hydraulic oil from a reservoir tank 23 and discharges the hydraulic oil to an oil passage P5 via a check valve 22a. . The oil passage P5 is branched into oil passages P6 and P7, and the branched oil passage P6 is connected to a connection point between the oil passages P1 and P2, and the oil passage P7 is connected to a connection point between the oil passages P3 and P4. Have been.

An accumulator 25 for accumulating high-pressure hydraulic oil in the oil passage P5 and using the accumulated hydraulic oil for raising the vehicle height is provided via an accumulator gate valve 26 constituted by an electromagnetic switching valve. It is connected.
The accumulator gate valve 26 is kept in the illustrated state by de-energization, and the hydraulic pressure of the oil passage P5 is reduced by the accumulator 25.
Only when the hydraulic pressure is somewhat higher than the hydraulic pressure of the hydraulic fluid from the hydraulic passage P5 to the accumulator 25. The accumulator gate valve 26 is switched from the illustrated state to the conductive state by energization.

A discharge valve 27 is interposed between the oil passage P5 and the reservoir tank 23. Discharge valve 27
Are always kept in a conductive state, and are mechanically switched to a non-conductive state when the discharge hydraulic pressure of the hydraulic pump 22 rises.

The electric motor 21 and the gate valve 1
A microcomputer 30 as control means is connected to 7a to 17d and the accumulator gate valve 26. The microcomputer 30 repeatedly executes a load state determination, a vehicle state detection, an abnormal state recovery program, a vehicle height adjustment program not described in the present embodiment, and the like shown in FIG. And controls the supply and discharge of hydraulic oil to and from the hydraulic cylinders 11a to 11d. Vehicle height sensors 32a to 32d and a hydraulic pressure sensor 34 are connected to the microcomputer 30.

The vehicle height sensors 32a-32 in this embodiment
The 32d detection principle will be described. A hole that converts vertical movement of the lower arm of each wheel into rotation of the shaft via a link and lever, and generates an electromotive force in the vertical direction of the semiconductor when a current flows through the semiconductor in the magnetic field in a direction perpendicular to the magnetic field. The Hall element that detects the strength of the magnetic field as an electric signal using the effect is rotated. At this time, the magnetic flux density changes due to the deviation of the directions of the current and the magnetic field. The vehicle height is detected by detecting the electromotive force at that time as a voltage signal proportional to the rotation angle of the shaft. Incidentally, a sliding resistance type vehicle height sensor may be used.

The vehicle height sensors 32a and 32b are connected to the left and right front wheels W.
The vehicle heights Hf1 and Hf2 are respectively provided between the lower arms 12a and 12b and the vehicle body 10 at positions W1 and W2 to detect the heights of the vehicle body 10 with respect to the road surface (unsprung members) at the front left and right wheels W1 and W2. Outputs a detection signal. The height sensors 32c and 32d are provided for the left and right rear wheels W3,
In the W4 position, the lower arms 12c and 12d and the vehicle body 10
Between the left and right rear wheels W3 and W4, respectively, to detect the height of the vehicle body 10 with respect to the road surface (unsprung member) and output detection signals representing the vehicle heights Hf3 and Hf4.

The pressure sensor 34 detects a hydraulic pressure transmitted through the metal diaphragm and the silicon oil with a semiconductor strain gauge on the silicon chip, and detects a voltage signal proportional to the hydraulic pressure. It detects the oil pressure of the oil passage P5 and outputs a detection signal representing the oil pressure P.

Next, the control of the embodiment configured as described above, that is,
The load state determination, vehicle state detection, and abnormal state recovery processing will be described with reference to the flowchart of FIG.

When an ignition switch (not shown) is turned on, the microcomputer 30 initializes various flags used in a program to be described later to "0" by executing a program (not shown). The detection and abnormal state recovery program is started to be repeatedly executed every predetermined short time.

In steps 101 and 102, it is determined whether or not the gate valves 17a to 17d are all conducting and the vehicle height rise control is being performed by another control device or the like not described in the present embodiment. . This is for the following reasons. In the present embodiment, the pressure sensor 34 is located between the discharge valve 27 and the pump 22 and the discharge valve 2
Only when the valve 7 is closed, that is, only when the pump 22 is driven (during vehicle height rise control), the pressure in the oil passage P5 can be detected. Also, the gate valves 17a to 17d
If any one of the wheels is in the conductive state, the load determination can be performed for the wheel having the gate valve in the conductive state.However, in the present embodiment, in order to detect the vehicle state from the determination result of the load state of each wheel, Information on the pressure on the wheel is required. From the above, the gate valves 17a to 17d are all in the conducting state, and the load state determination /
The vehicle state cannot be detected.

The pressure sensors are connected to the gate valves 17a to 17d on the oil passages P1 to P4 and the hydraulic cylinders 11a to 11d.
Needless to say, in the case where they are provided between the wheels, the load state of each wheel can be always determined, and the present invention may be implemented as such.

If it is determined in steps 101 and 102 that the vehicle height raising control is not being performed or that any of the gate valves 17a to 17d is not in the conducting state, the vehicle height raising control is being performed and both of the gate valves 17a to 17d are being controlled. Step 101 or Step 10 until it becomes conductive
Steps 1 and 102 are repeated. That is, in the present embodiment, the vehicle is in the vehicle height increasing control and the gate valve 17
Except when all of a to 17d are in the conductive state, the load state determination of each wheel, the vehicle state detection, and the abnormal state recovery processing are not performed.

In order to determine the load state even during the vehicle height lowering control in which all the gate valves 17a to 17d are conducted, the vehicle height lowering control is intentionally performed to a vehicle height lower than the target vehicle height. After that, the gate valves 17a to 17
The vehicle height d may be controlled to the target vehicle height while both of them remain in the conductive state.

If it is determined in steps 101 and 102 that the vehicle height rise control is being performed and that all of the gate valves 17a to 17d are conducting, step 103 is executed.
, The respective detection signals representing the vehicle heights Hf1 to Hf4 and the pressure P from the vehicle height sensors 32a to 32d and the pressure sensor 34 are input. If the vehicle heights Hf1 to HF4 and the pressures P from the sensors 32a to 32d and 34 are used as they are, they include instantaneous changes. Hf1 to Hf4 and the pressure P may be low-pass filtered and used.

After each detected value is input in step 103, the process proceeds to step 104, in which a pressure boundary value for each load state is calculated from the input detected vehicle height based on the vehicle height-pressure characteristic map shown in FIG. Is done. The load state determination based on the pressure boundary value is performed independently for the detected vehicle height of each wheel. However, since the processing performed on each wheel is the same,
The load state determination on the left front wheel W1 will be described.

First, the criteria for determining the load state will be described. In the vehicle height-pressure characteristic map shown in FIG.
Shows the design characteristics of the internal pressure P of the hydraulic cylinder 11a with respect to the vehicle height Hf1 at the wheel W1 position. Note that Lm, N, and Hm on the x-axis representing the vehicle height represent the design minimum vehicle height, standard vehicle height, and maximum vehicle height, respectively.

When the vehicle height value Hf1 and the pressure value P detected by the vehicle height sensor 32a and the pressure sensor 34 are plotted on this map, the point (hereinafter referred to as a detected load point) is located in any region of FIG. The load state of the wheel W1 can be determined depending on whether it is performed. Hereinafter, the intersection of the straight line x = Lm and the straight line Y will be specifically described as the origin of the horizontal axis vehicle height Hf1 and the vertical axis pressure P. If the absolute value of the difference from the intercept of the straight line Y has an intercept within t1, and the load point is on a straight line parallel to the straight line Y, a normal vehicle height-pressure characteristic having substantially the same characteristics as the designed vehicle height-pressure characteristics is obtained. The normal state representing the load state is determined.

If the absolute value of the difference from the intercept of the straight line Y is greater than t1 and less than t2, and there is a load point on a straight line parallel to the straight line Y and above the straight line Y in FIG. It is determined that the vehicle is in a high load state having characteristics slightly deviating from the designed vehicle height-pressure characteristics. Further, if the absolute value of the difference from the intercept of the straight line Y is greater than t1 and less than t2, and there is a load point on a straight line parallel to the straight line Y and below the straight line Y in FIG. It is determined that the vehicle is in a low load state having characteristics slightly deviating from the above vehicle height-pressure characteristics.

If there is an intercept in which the absolute value of the difference from the intercept of the straight line Y is greater than t2, and there is a load point on a straight line parallel to the straight line Y and above the straight line Y in FIG. It is determined that the vehicle is in a high load abnormal state having characteristics extremely deviating from the vehicle height-pressure characteristics. At this time, when the detected vehicle height is N or more, it is referred to as abnormal state A, and when it is smaller than N, it is referred to as abnormal state B.
If the load point is on a straight line that is parallel to the straight line Y and below the straight line Y in FIG. It is determined that the state is a low load or higher state having characteristics extremely deviating from the high-pressure characteristics. When the detected vehicle height at this time is N or more, the abnormal state C,
When it is smaller than N, it is called an abnormal state D.

Here, returning to the flowchart of FIG.
A description will be given of a load state determination process in the microcomputer 30 based on the above-described determination criterion.

In step 104, based on the map shown in FIG. 4 stored in the ROM (not shown) of the microcomputer 30, a pressure boundary value PFL (Hf1) between the low load abnormal state and the low load state with respect to the vehicle height detection value Hf1. ,
Pressure boundary value PL (Hf1) between the low load state and the normal state,
Pressure boundary value PH (Hf1) between the normal state and the high load state,
Pressure boundary value PFH (H
f1) are calculated respectively.

Next, the routine proceeds to step 105, where the detected pressure value P
Is smaller than PFL (Hf1), that is, it is in a low load abnormal state. If it is determined in step 105 that the detected pressure value P is smaller than PFL (Hf1), the process proceeds to step 106, where the detected vehicle height value H
It is determined whether or not f1 is smaller than N, that is, whether or not the state is the abnormal state D. In step 106, Hf1
Is smaller than N, the routine proceeds to step 107, where a flag indicating the abnormal state D is set, and Hf1 becomes N.
If it is determined that it is not smaller, the process proceeds to step 108, where a flag indicating the abnormal state C is set, and then the process proceeds to step 201.

At step 105, the detected pressure value P becomes P
If it is determined that the detected pressure value is not smaller than FL (Hf1), the process proceeds to step 109, and it is determined whether the detected pressure value P is smaller than PL (Hf1), that is, whether or not the vehicle is in a low load state. In step 109, the detected pressure value P becomes P
If it is determined that it is smaller than L (Hf1), the routine proceeds to step 110, where a flag indicating a low load state is set, and then the routine proceeds to step 201. In step 109,
If it is determined that the detected pressure value P is not smaller than PL (Hf1), the process proceeds to step 111, where the detected pressure value P is
It is determined whether or not H (Hf1) or less, that is, whether or not the normal state.

If it is determined in step 111 that the detected pressure value P is equal to or less than PH (Hf1), the process proceeds to step 112, where a flag indicating a normal state is set, and then the process proceeds to step 201. In step 111,
If it is determined that the detected pressure value P is not less than PH (Hf1), the process proceeds to step 113, where the detected pressure value P is
It is determined whether or not (Hf1) or less, that is, whether or not the load is high.

If it is determined in step 113 that the detected pressure value P is equal to or less than PFH (Hf1), the routine proceeds to step 114, where a flag indicating a high load state is set, and then the routine proceeds to step 201. If it is determined in step 113 that the detected pressure value P is not lower than PFH (Hf1), the process proceeds to step 115, where the detected vehicle height value Hf is determined.
It is determined whether 1 is smaller than N, that is, whether or not an abnormal state B is present. In step 115, if it is determined that Hf1 is smaller than N, the process proceeds to step 116, a flag indicating an abnormal state B is set, and if it is determined that Hf1 is not smaller than N, the process proceeds to step 117 and the process proceeds to step 117. After the flag indicating the state A is set, the process proceeds to step 201.

With the above control flow, the load state flag is set on the left front wheel W1, and it is determined that the load state of W1 belongs to any of the seven load states shown in the map of FIG. Become.

In step 201 and subsequent steps, abnormal condition recovery processing or vehicle condition detection is performed based on the load condition determined for each wheel. In the above description of the load state determination, for the sake of convenience, the description is limited to the left front wheel W1.
Hereinafter, in the description of the abnormal state recovery processing and the vehicle state detection, the determined load states of the wheels W1 to W4 will be used.

First, the vehicle state detection criteria will be described. FIG. 5 shows each wheel load state-vehicle state map. For example, when the load states of the left front wheel W1 and the right front wheel W2 are both high load states, and the load states of the left rear wheel W3 and the right rear wheel W4 are both low load states, from FIG. "Slope" is detected. Also, the load state of both the left front wheel W1 and the left rear wheel W3 is a high load state, and the right front wheel W2 and the right rear wheel W4
If both of the load states are low load states, the vehicle state is detected as “Left slope road” in state IV from FIG. Hereinafter, other vehicle states are similarly detected based on the detection criteria shown in FIG.

Note that the determination conditions of the state III and the state VI are determined mainly based on the fact that a baggage is often loaded at the rear of the vehicle. Needless to say, these determination conditions may be arbitrarily changed depending on the vehicle type). In addition to the vehicle state shown in FIG. 5, combinations of the load states of the respective wheels are conceivable, and these combinations may be added as another vehicle state determination condition.

As described above, for the detected load state of each wheel, the state of loading on the vehicle, the vehicle state such as the traveling state of the vehicle and the stopped road surface can be detected using the map shown in FIG. .

Here, returning to the flowchart of FIG.
A process of detecting a vehicle state based on the above-described detection criteria in the microcomputer 30 will be described. Further, the abnormal state recovery processing will be described together with a flowchart showing details of the abnormal state recovery processing of FIG.

In step 201, the wheels W1 to W
It is determined whether the load state of one of the wheels 4 is abnormal. That is, it is determined whether or not a flag indicating the abnormal state A to D is set in at least one of the wheels W1 to W4. In step 201, when it is determined that the load state is not abnormal in all the wheels W1 to W4, the process proceeds to step 202, and the vehicle state is detected. In step 202,
The flag of the load state of each wheel is made to correspond to the map of FIG. 5 stored in the ROM (not shown) of the microcomputer 30 and the state of the vehicle is detected. In step 210, a flag corresponding to the vehicle state detected in step 202 is set. Although this flag is not described in detail in the present embodiment, a vehicle equipped with a damping force control device for electrically controlling the opening degree of the variable orifices 15a to 15d and a control means different from the control means in the present embodiment. Another control device such as a high adjustment device refers to the flag as control information. After the flag is set in step 210,
Proceeding to step 211, the process returns to step 100 and the same processing is repeated.

The flag set in step 210 is referred to control means such as a damping force control device and a vehicle height adjustment device to correct the damping force and the vehicle height based on the loading condition and the vehicle condition such as a running road surface. And the ride comfort and maneuverability can be improved.

In step 201, the wheels W1 to W4
When it is determined that the load state of one of the wheels is abnormal, the process proceeds to step 203. FIG. 3 shows the details of the processing in step 203.

The processing in step 203 will be described.
The following processing is performed independently for each abnormal wheel.

In step 203A, prior to the abnormality recovery processing, the processing by the control means of the other control device is interrupted and the control is interrupted. Step 2
At 04, it is determined whether or not the abnormal state is the abnormal state A or C for each wheel determined to be abnormal. If it is determined in step 204 that the abnormal state of the abnormal wheel is the abnormal state A or the abnormal state C, the process proceeds to step 205, and the vehicle height lowering process is performed until the vehicle height decreases to N. Proceeding to 207, if it is determined that the vehicle is in the abnormal state B or abnormal state D, the flow proceeds to step 206, where the vehicle height increasing process is performed until the vehicle height reaches N, and the flow proceeds to step 207. If the vehicle height lowering process and the vehicle height raising process are performed on different wheels, the vehicle height raising process may be given priority in consideration of the risk when the vehicle height is low. The rise or fall of the vehicle height is achieved by closing a gate valve other than the wheel to be controlled, and supplying or discharging hydraulic oil to or from the hydraulic cylinder of the wheel to be controlled via any of the oil passages P1 to P4. Achieved. After the vehicle height lowering / raising process for recovering from these abnormalities has been completed for all abnormal wheels, the pumps are opened to open gate valves other than the closed control target wheels and to determine the load state of the abnormal wheels again. 22 is simulated.

In step 207, it is determined whether or not the load condition of the abnormal wheel has recovered. Here, the vehicle height value and the pressure value are detected again, and the load state of the abnormal wheel is determined again based on the map of FIG. 5, but the determination method is the same as the processing from step 104 to step 200. Therefore, the description is omitted.

If it is determined in step 207 that the load state of all the abnormal wheels has recovered from the abnormal state to the high / low load state or the normal state, step 207
Proceeding to A, the control interruption to the control means of the other control device performed in step 203A is released. Thereafter, the process proceeds to step 211, returns to step 100, and the same processing is repeated.

If it is determined in step 207 that the load state of one of the abnormal wheels is still in an abnormal state, the interruption of the control to the control means of the other control device in step 203A is performed. Without being released, the process proceeds to step 211 and returns to step 100. However, since the control is actually interrupted, NO is continuously determined in step 102 until the ignition switch is turned off.
Virtually none of the controls described so far will be performed.

That is, if the determination of NO is made in step 207, it indicates that the control of the vehicle height adjusting device in this embodiment is abnormal, and the damping force not described in this embodiment is used for fail safe. Control by control means of another control device such as a control device is interrupted (substantially prohibited).

Since the target value of the vehicle height in the processing of steps 205 and 206 is N, when the abnormality cannot be recovered in step 207 and the subsequent control is prohibited, the vehicle height is stopped at a position close to the N position. The fail-safe property can be improved.

In the above-described embodiment, the sensor configuration has one pressure sensor and four vehicle height sensors having four wheels. However, the present invention is not limited to this configuration. Even if sensors are provided on four wheels and one vehicle height sensor is provided, for example, at the center of the vehicle body, the load state of each wheel can be determined. In this case, the input values at step 103 in the flowchart shown in FIG. 1 are the actuator pressures Pf1 to Pf4 of each wheel and the vehicle height H. In the subsequent steps, if the vehicle height and the pressure are exchanged, the load determination is performed in the same manner. , Vehicle state detection is performed. In this case, when pressure sensors are provided on the downstream side of the gate valves 17a to 17d, it is possible to determine the load without performing the vehicle height increase control as in the present embodiment.

As described above, both the pressure sensor and the vehicle height sensor may have a sensor configuration in which four wheels are provided. In this case, the load can be more accurately determined for each wheel.

The wheel position in the claims of the present invention does not mean only the position corresponding to the four wheels of the vehicle, but the rear wheel position such as the position between the left rear wheel and the right rear wheel. Also refers to. That is, any one of the vehicle height sensor and the pressure sensor in the present invention is not necessarily provided for four wheels, and one vehicle height sensor is provided as a rear wheel vehicle height sensor at the rear of the vehicle (rear wheel position). A modified example in which two left front wheel and right front wheel vehicle height sensors are provided at the front of the vehicle and one pressure sensor is provided at the vehicle is also conceivable. In this case, the number of parts that can determine the load state is one for the rear wheel, and one for each of the left front wheel and the right front wheel, so that the vehicle state detection criteria shown in FIG. What is necessary is just to change to what was based on the load state of a part.

In the above-described embodiment, an example in which the present invention is applied to a hydraulic vehicle height adjusting device using hydraulic oil has been described. However, the present invention is arranged in parallel with a mechanical spring. Then, the present invention can be applied to an air-type vehicle height adjusting device using another fluid, for example, air. In this case, the hydraulic pump 2
2 and changing the hydraulic cylinders 11a to 11d into pneumatic pumps and pneumatic cylinders, other accumulators 25 and various valves 17a to 17d, 26,
27 may be changed to a pneumatic type.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a load state determination, vehicle state detection, and abnormal state recovery program executed by the microcomputer of FIG. 2;

FIG. 2 is an overall schematic diagram of a vehicle height adjustment device according to one embodiment of the present invention.

FIG. 3 is a flowchart showing an abnormal state recovery process executed by the microcomputer of FIG. 2;

FIG. 4 is a vehicle height-pressure characteristic map stored in a ROM of the microcomputer of FIG. 2;

FIG. 5 is a wheel load state-vehicle state map stored in the ROM of the microcomputer of FIG. 2;

FIG. 6 is a diagram illustrating a configuration of a load detection device according to a conventional example.

[Explanation of symbols]

 W1 left front wheel W2 right front wheel W3 left rear wheel W4 right rear wheel 1 ... absorber according to conventional example 2 ... pressure detecting means according to conventional example 3 ... Spring in load detecting means according to a conventional example 10 ... Car body 11a-11d ... Hydraulic cylinder 12a-12d ... Lower arm 13a-13d ... Piston rod 14a-14d ... Coil spring 15a-15d ... Variable orifices 17a to 17d Gate valves 17a and 17c Fixed orifices 21 Electric motor 22 Hydraulic pump 22a Check valve 23 Reservoir tank 25 Accumulator 26 ..Accumulator gate valve 27 ... Discharge valve 30 ... Microcomputer 32a-32d ... Vehicle height sensor 34 ... hydraulic pressure sensor

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hirofumi Endo 2-1-1 Asahi-cho, Kariya-shi, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (3)

[Claims] 1. A vehicle height detecting means for detecting a value based on a vehicle height, and a plurality of vehicles provided between a plurality of wheels and a vehicle body and capable of increasing and decreasing the vehicle height at each wheel position by fluid supplied and discharged. An actuator, and pressure detecting means for detecting a value based on the internal pressure of the actuator, based on a value based on the vehicle height detected by the vehicle height detecting means and an internal pressure of the actuator detected by the pressure detecting means A load state determining device for a vehicle, wherein the load state of the vehicle is determined based on the value. 2. A vehicle height detecting means for detecting a value based on the vehicle height, and a plurality of vehicle heights at each wheel position which are provided between the plurality of wheels and the vehicle body and capable of increasing or decreasing the vehicle height at each wheel position. An actuator, a pressure detecting means for detecting a value based on the internal pressure of the actuator, a value based on the vehicle height detected by the vehicle height detecting means, and a value based on the internal pressure of the actuator detected by the pressure detecting means. A load state determining means for determining a load state, wherein at least one of the vehicle height detecting means and the pressure detecting means detects a vehicle height or a pressure at a plurality of wheel positions of the vehicle. A vehicle state detection device for detecting a vehicle state from a state determination result. 3. A plurality of actuators provided between a plurality of wheels and a vehicle body and capable of increasing / decreasing a vehicle height at each wheel position by fluid supplied / discharged, and fluid can be supplied / discharged to / from the actuators. Fluid supply / discharge means, pressure detection means for detecting a value based on the internal pressure of the actuator, vehicle height detection means for detecting a value based on the vehicle height,
Control means for controlling the fluid supply / discharge means so as to eliminate a deviation of a value based on the detected vehicle height from a predetermined target vehicle height, wherein the vehicle height detection means and the pressure detection At least one of the means detects a vehicle height or a pressure at a plurality of wheel positions of the vehicle, and the control means detects a value based on the vehicle height detected by the vehicle height detecting means and the pressure detected by the pressure detecting means. A load state discriminating means for discriminating a normal / abnormal load state of a plurality of wheel positions by a value based on the pressure inside the actuator, and when the load state is judged to be abnormal by the load state discriminating means. A vehicle height adjusting device, wherein the fluid supply / discharge means is controlled so as to shift a load state of a wheel position in an abnormal state to a normal state.