JP2013043587A - Air suspension control device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air suspension control device for a vehicle capable of surely controlling crouching, capable of restraining consumption of compressed air, and capable of also surely preventing even an attitudinal change in a vehicle rear part caused by getting on and off of a passenger, while preventing floating of right-left one front wheel of the vehicle, even if a height of a road surface for grounding the front wheel of the vehicle is different between the right and the left.SOLUTION: In an ordinary mode, it is determined whether or not the vehicle stays in the wavy road. When the vehicle stays in a wavy road, leveling control of the respective right-left in the vehicle rear part is forcibly rested, and when crouching control is executed in a leveling control resting state of a vehicle height of the respective right-left in the vehicle rear part, when an average value of the right-left vehicle heights in a vehicle front part falls within a crouching control reference range, the vehicle height of the respective right-left in the vehicle rear part is stored. The vehicle height of the respective right-left in the vehicle rear part is held in the stored value up to finishing crouching control.

Description

  The present invention relates to a vehicle air suspension control device.

  In general, in the case of a vehicle such as a bus equipped with an air suspension control device and the entrance is provided on the front side, the wheel moves up and down due to unevenness or inclination of the road surface or the vehicle body tilts when driving or stopping. Even if it is going to do, leveling control to hold the car body parallel to the axle by holding the left and right vehicle heights independently at a constant height is performed, but when passengers get on and off, the entrance / exit is Crouching control is performed to lower the vehicle height at the front part of the vehicle so that passengers can easily get on and off.

  FIG. 4 is an overall schematic configuration diagram showing an example of a conventional vehicle air suspension control device, in which 1 is a vehicle such as a bus, 2 is a front wheel of the vehicle 1, and 3 is a rear wheel of the vehicle 1. The air suspension control device is provided with a total of four front air springs 4 arranged one by one on the left and right so as to support the front wheel 2 and two pieces on the left and right two sides so as to support the rear wheel 3. A rear air spring 5, a front vehicle height adjustment valve 8 provided in an air pipe 7 connecting the front air spring 4 and the air tank 6, and supplying / discharging compressed air in the air tank 6 to / from the front air spring 4, respectively; Provided in an air line 9 that branches off from the air line 7 and connects the rear air spring 5 and the air tank 6 to the rear air spring 5. A rear vehicle height adjustment valve 10 for supplying and discharging the vehicle, a front vehicle height sensor 11 such as a potentiometer for electrically detecting left and right vehicle heights 11a at the front portion of the vehicle 1, and a left and right vehicle heights 12a at the rear portion of the vehicle 1 respectively. A rear vehicle height sensor 12 such as a potentiometer that is electrically detected, and a front vehicle height adjustment valve 8 and a rear vehicle height based on vehicle heights 11a and 12a detected by the front vehicle height sensor 11 and the rear vehicle height sensor 12. And a controller 13 that outputs control signals 8a and 10a to the regulating valve 10.

  In addition, the driver's seat of the vehicle 1 such as the bus is configured to perform crouching control so that the front portion of the vehicle 1 is lowered when the driver is turned ON / OFF and a predetermined condition is satisfied in the ON state. A crouching switch 14 is provided, and the crouching switch 14 is connected to the controller 13.

  Although not shown, the controller 13 is also connected to a vehicle height adjustment control switch for performing vehicle height adjustment control for raising and lowering the vehicle height of the vehicle 1 to a required height as necessary. It is used when parking at low parking lots or when boarding a ferry.

  In the vehicle air suspension control device, when the vehicle is running or stopped, the front vehicle height sensor 11 detects the left and right vehicle heights 11a in the front portion of the vehicle 1 and inputs them to the controller 13. In the controller 13, the vehicle 13 An average value of the left and right vehicle heights 11a in one front is calculated, and the average value is compared with a preset reference range, and the left and right vehicle heights 11a in the front of the vehicle 1 are compared with the reference range. When the average value is low, compressed air is simultaneously supplied to the left and right front air springs 4 by the control signal 8a to the front vehicle height adjusting valve 8, and the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 from the reference range is When it is high, compressed air is discharged simultaneously from the left and right front air springs 4 by a control signal 8a to the front vehicle height adjustment valve 8. It is. At the same time, the rear vehicle height sensor 12 detects the left and right vehicle heights 12a at the rear of the vehicle 1 and inputs them to the controller 13. In the controller 13, the left and right vehicle heights 12a at the rear of the vehicle 1 are set in advance as a reference. When the left and right vehicle heights 12a at the rear portion of the vehicle 1 are lower than the reference range, compressed air is supplied to the left and right rear air springs 5 by a control signal 10a to the rear vehicle height adjusting valve 10. On the contrary, when the left and right vehicle heights 12a at the rear portion of the vehicle 1 are higher than the reference range, the compressed air is discharged from the left and right rear air springs 5 by the control signal 10a to the rear vehicle height adjusting valve 10. In this way, leveling control is performed, and the left and right vehicle heights are independently maintained at a constant height even if the wheels move up and down due to the unevenness or inclination of the road surface or the vehicle body tilts. The vehicle body is held parallel to the axle so that the vehicle 1 is less likely to roll over and stability is increased. It is well known that the inclination correction of the vehicle 1 is more effective when it is performed on the rear axle side with a large axial load and a wide tread.

  On the other hand, when the driver runs the vehicle 1, arrives at a stop or the like, stops the vehicle 1, and operates the parking brake, when the crouching switch 14 is turned on by the driver, as described above, The front vehicle height sensor 11 detects the left and right vehicle heights 11a at the front portion of the vehicle 1 and inputs them to the controller 13. The controller 13 calculates the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1, The average value is compared with a reference range for crouching control set in advance lower than the reference range, and the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 is within the reference range for crouching control. Simultaneously from the left and right front air springs 4 by a control signal 8a output from the controller 13 to the front vehicle height adjustment valve 8. Condensed air is discharged. In this way, in the case of a vehicle 1 such as a bus provided with a boarding gate at the front side, crouching control is performed, and the vehicle height at the front of the vehicle 1 provided with the boarding gate is lowered when passengers get on and off. It becomes possible to easily get on and off passengers.

  For example, Patent Document 1 shows a general technical level related to the vehicle air suspension control apparatus as described above.

Japanese Patent Laid-Open No. 7-205630

  However, for example, on an uphill road, as shown in FIG. 5A, the height of the road surface on which the front wheel 2 on the right side of the vehicle 1 contacts is significantly higher than that on the left side. As shown in FIG. 5 (b), the road surface to be touched is a “swell road” where the right side is lower as opposed to the front wheel 2 side. When the control is performed and the compressed air is simultaneously discharged from the left and right front air springs 4 at the front of the vehicle 1, the bump stopper built in the right front air spring 4 serves as an upper surface plate of the front air spring 4. In some cases, the rubber contact state may occur, so that it cannot contract any further in the height direction.

  If the right front air spring 4 is in a rubber contact state before the average value of the left and right vehicle heights 11a in the front portion of the vehicle 1 falls within the reference range for crouching control, the left front air spring 4 Further, the compressed air is continuously discharged. However, if the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 does not fall to the reference range for crouching control, the inside of the front air spring 4 on the left side is left. There is almost no compressed air, and the left front air spring 4 is further compressed by a stabilizer reaction force.

  Moreover, at the same time, compressed air is supplied to the left rear air spring 5 at the rear portion of the vehicle 1, and compressed air is discharged from the right rear air spring 5 at the rear portion of the vehicle 1, Leveling control is performed so that the vehicle body is parallel to the right-downward road surface on which the rear wheel 3 of the vehicle 1 contacts the ground, as indicated by the phantom line in FIG. There was a problem that the front wheel 2 was lifted.

  Further, for example, as shown in FIG. 5A, the height of the road surface on which the front wheel 2 on the right side of the vehicle 1 contacts is significantly higher than that on the left side, and the height of the road surface on which the rear wheel 3 of the vehicle 1 contacts the ground. Is compressed simultaneously from the left and right front air springs 4 at the front of the vehicle 1 even in a situation where there is almost no difference in height between the left and right front wheels 2 on the left side of the vehicle 1. When the air is discharged, the bump stopper built in the right front air spring 4 comes into contact with the upper surface plate of the front air spring 4 and cannot be further contracted in the height direction, as described above. You may fall into contact. If the right front air spring 4 is in a rubber contact state before the average value of the left and right vehicle heights 11a in the front portion of the vehicle 1 falls within the reference range for crouching control, the left front air spring 4 Further, since the compressed air is continuously discharged, not only the vehicle height 11a on the left side in the front portion of the vehicle 1 but also the vehicle height 12a on the left side in the rear portion of the vehicle 1 is lowered. When the vehicle is tilted to the left, the leveling control still works, and the compressed air is supplied to the left rear air spring 5 at the rear of the vehicle 1, so that the front wheel 2 on the left side of the vehicle 1 does not lift up as described above. The average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 is increased, and the average value of the left and right vehicle heights 11a should be within the reference range for crouching control. Compressed air is discharged from the front air spring 4 on the left side and the left side, and thereafter, the same operation as described above is repeated, the crouching control and the leveling control are alternately performed, the control is not converged, and all the compressed air in the air tank 6 is exhausted. There was a possibility that the vehicle body would continue to move up and down until it was consumed.

  Furthermore, in order to solve the above problems, the inventor determines that the vehicle 1 is on a wavy road in a situation where no crouching control and vehicle height adjustment control are performed. Has been proposed to forcibly stop the leveling control of the left and right vehicle heights 12a, but in this case, by moving in the vehicle or getting on and off the passenger in order to get on and off, It has been found that there is a possibility that a posture change occurs in the rear part of the vehicle 1.

  In view of such circumstances, the present invention reliably performs the crouching control while preventing the left and right front wheels from rising even if the height of the road surface on which the front wheels of the vehicle touch the ground is different on the left and right. Therefore, an object of the present invention is to provide a vehicle air suspension control device that can suppress the consumption of compressed air and that can reliably prevent a change in posture at the rear of the vehicle due to passengers getting on and off.

The present invention includes a front air spring disposed to support a front wheel of a vehicle,
A rear air spring disposed to support the rear wheel of the vehicle;
A front vehicle height adjustment valve for supplying and discharging compressed air in an air tank to the front air spring;
A rear vehicle height adjustment valve for supplying and discharging compressed air in an air tank to the rear air spring;
A front vehicle height sensor for detecting left and right vehicle heights at the front of the vehicle;
A rear vehicle height sensor for detecting left and right vehicle heights at the rear of the vehicle;
By outputting control signals to the front vehicle height adjustment valve and the rear vehicle height adjustment valve based on the vehicle heights detected by the front vehicle height sensor and the rear vehicle height sensor, the vehicle heights at the left and right at the rear of the vehicle are set to a constant height. In addition, leveling control is performed to keep the vehicle body parallel to the axle, and when passengers get on and off, crouching control is performed to lower the vehicle height at the front of the vehicle where the entrance is provided. A vehicle air suspension control device comprising a controller for performing vehicle height adjustment control for raising and lowering the vehicle to a required height,
When it is determined that the vehicle is on a wavy road during the normal mode in which the crouching control and the vehicle height adjustment control are not performed, the left and right vehicle height leveling control at the rear of the vehicle is forcibly stopped. ,
Leveling control of the left and right vehicle heights at the rear of the vehicle When crouching control is performed in an inactive state, the left and right of the rear of the vehicle at the time when the average value of the left and right vehicle heights is within the reference range for crouching control A vehicle air suspension control device characterized in that each vehicle height is stored and the left and right vehicle heights at the rear of the vehicle are held at the stored values until cruching control ends. It is.

  According to the above means, the following operation can be obtained.

  With the above-described configuration, when it is determined that the vehicle is on a wavy road during the normal mode, the left and right leveling controls at the rear of the vehicle are forcibly stopped, and from this state, the crouching control is performed, When the compressed air is discharged from the left and right front air springs at the same time, the bump stopper built in the front air spring on one of the left and right sides comes into contact with the top plate of the front air spring and moves it in the height direction. It falls into a rubber contact state where it can no longer contract, and compressed air continues to be discharged from the front air springs on the other side of the left and right sides. Even so, the average value of the left and right vehicle heights at the front of the vehicle reaches the reference range for crouching control. If not lowered, there is almost no compressed air in the front air springs on the left and right sides. Although the front air springs on the other side of the left and right sides are further contracted by the stabilizer reaction force, the left and right leveling control at the rear of the vehicle has already been stopped, so that the left and right rear air springs at the rear of the vehicle The compressed air is not supplied and discharged, and it is avoided that the leveling control works so that the vehicle body is parallel to the lower right road surface on which the rear wheel of the vehicle comes into contact with the front wheel on the left and right sides of the vehicle. There is no worry that will rise up.

  Subsequently, the left and right vehicle heights at the rear of the vehicle when the average value of the left and right vehicle heights at the front of the vehicle is within the reference range for crouching control are stored, and the left and right vehicle heights at the rear of the vehicle are stored. While being held at the value, the passenger can easily get on and off in a state where the average value of the left and right vehicle heights in the front portion of the vehicle is held in the reference range for crouching control.

  Here, if the leveling control of the left and right vehicle heights at the rear part of the vehicle is only forcibly stopped, the passenger can move in the vehicle to get on and off or change the posture at the rear part of the vehicle. However, in the present invention, the left and right vehicle heights at the rear of the vehicle at the time when the average value of the left and right vehicle heights at the front of the vehicle is within the reference range for crouching control is stored. Since the vehicle height is maintained at the stored value, the posture at the rear portion of the vehicle is stable without change, and is extremely effective.

  As a result, it is avoided that crouching control and leveling control are alternately performed so that control does not converge, and the vertical movement of the vehicle body continues until all the compressed air in the air tank is consumed. Not only forcibly stopping the leveling control of the left and right vehicle heights at the rear part of the vehicle, but also when the average value of the left and right vehicle heights at the front part of the vehicle falls within the reference range for crouching control. The left and right vehicle heights at the rear of the vehicle at the rear are stored, and the left and right vehicle heights at the rear of the vehicle are held at the stored values, so that passengers moved in and out of the vehicle to get on and off Even so, there is no concern that the posture change will occur at the rear of the vehicle.

  In the vehicle air suspension control device, the absolute value of the difference between the left and right vehicle heights at the front portion of the vehicle detected by the front vehicle height sensor is greater than or equal to a preset first threshold value, and the front vehicle height sensor When the product of the difference between the left and right vehicle heights detected at the front of the vehicle and the difference between the left and right vehicle heights detected at the rear vehicle height sensor is negative, or the rear vehicle height sensor When the absolute value of the difference between the left and right vehicle heights detected at the rear of the vehicle and the reference vehicle height is equal to or less than a preset second threshold value, it can be determined that the vehicle is on a wavy road. Then, for example, the height of the road surface on which the front wheels on the left and right sides of the vehicle are grounded is significantly higher than the other side of the left and right sides, and the height of the road surface on which the rear wheels of the vehicle are grounded is It seems that the side is lower Alternatively, the height of the road surface on which the front wheels on the left and right sides of the vehicle are grounded is significantly higher than that on the left and right sides, and the height of the road surface on which the rear wheels of the vehicle are grounded is It is determined that the vehicle is on a undulating road when there is almost no difference in height between the left and right sides, which is equal to the height of the road surface on the ground.

  According to the vehicle air suspension control device of the present invention, the crouching control is performed while preventing the front wheels on the left and right sides of the vehicle from being lifted even if the height of the road surface on which the front wheels of the vehicle touch the ground is different on the left and right. It can be performed reliably, and consumption of compressed air can be suppressed, and further, an excellent effect that posture change at the rear of the vehicle accompanying passenger getting on and off can be surely prevented.

It is a flowchart which shows the waviness determination in the Example of the air suspension control apparatus for vehicles of this invention. 6 is a flowchart showing a situation in which the leveling control of the vehicle left and right vehicle heights is stopped when the vehicle is on a wavy road in the embodiment of the vehicle air suspension control device of the present invention. In the embodiment of the vehicle air suspension control device of the present invention, when the crouching control is performed when the vehicle is on a wavy road, the vehicle front left and right vehicle height average value falls within the reference range for crouching control. It is a flowchart which shows the condition which memorize | stores the vehicle height of vehicle rear part right and left, respectively, and hold | maintains the vehicle height of vehicle rear part right and left in this stored vehicle height. It is a whole schematic block diagram which shows an example of the conventional air suspension control apparatus for vehicles. BRIEF DESCRIPTION OF THE DRAWINGS It is the schematic which shows an example of the condition where a vehicle is on a wavy road, (a) is a figure which shows the state where the height of the road surface of the right side which a front wheel of a vehicle contacts is higher than the left side, (b) is a rear wheel of a vehicle. It is a figure which shows the state in which the height of the road surface of the left side which contacts is higher than the right side.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  FIGS. 1 to 3 show an embodiment of a vehicle air suspension control apparatus according to the present invention. The basic configuration is the same as that of the conventional apparatus shown in FIGS. However, as shown in FIGS. 1 to 3, during normal mode, it is determined whether or not the vehicle 1 is on a wavy road. When the vehicle 1 is on a wavy road, the left and right leveling at the rear of the vehicle 1 is determined. When the control is forcibly stopped and the crouching control is performed in the leveling control stop state of the left and right vehicle heights 12a at the rear part of the vehicle 1, the average value of the left and right vehicle heights 11a at the front part of the vehicle 1 is used for the crouching control. The left and right vehicle heights 12a at the rear portion of the vehicle 1 at the time when the vehicle is within the reference range are stored, and the left and right vehicle heights 12a at the rear portion of the vehicle 1 are stored until the cruching control is completed. It lies in that is configured to hold the.

  First, in step S1 of FIGS. 1 to 3, the normal mode refers to a state where the crouching control and the vehicle height adjustment control are not performed at the time of running or stopping.

  In step S2 in FIG. 1, it is determined whether or not the vehicle 1 is on a wavy road, for example, as shown in FIG. 5A, the height of the road surface on which the front wheel 2 on the right side of the vehicle 1 contacts is significantly higher than the left side. The height of the road surface on which the rear wheel 3 of the vehicle 1 comes into contact with the ground is high, as shown in FIG. 5 (b). For example, as shown in FIG. 5A, the height of the road surface on which the front wheel 2 on the right side of the vehicle 1 touches is significantly higher than that on the left side, and the height of the road surface on which the rear wheel 3 of the vehicle 1 touches is It is possible to determine that the vehicle 1 is on a wavy road in any of the situations where the left front wheel 2 of the vehicle 1 is equal to the height of the road surface on which the vehicle touches the ground and there is almost no difference in height between the left and right.

Here, the determination of the swell road in the step S2 is expressed by a mathematical expression:
[Equation 1]
| FR-FL | ≧ ΔF0
Where FR: right vehicle height at the front of the vehicle 1 FL: left vehicle height at the front of the vehicle 1 ΔF0: absolute value threshold (first threshold) of left and right vehicle height differences at the front of the vehicle 1
And [Equation 2]
(FR-FL) × (RR-RL) ≦ 0
RR: right vehicle height at the rear of the vehicle 1 RL: left vehicle height at the rear of the vehicle 1 or [Equation 3]
(| RR-RS | ≦ ΔR0 and | RL-RS | ≦ ΔR0)
However, RS: reference vehicle height at the rear of the vehicle 1 ΔR0: threshold of absolute value of difference between the left and right vehicle heights at the rear of the vehicle 1 and the reference vehicle height (second threshold)
It becomes.

  That is, the condition of [Equation 1] is that the absolute value of the difference between the left and right vehicle heights 11a detected by the front vehicle height sensor 11 (see FIG. 4) is greater than or equal to a preset first threshold value ΔF0. The condition of [Equation 2] indicates that the difference between the left and right vehicle heights 11a detected by the front vehicle height sensor 11 and the vehicle detected by the rear vehicle height sensor 12 (see FIG. 4). 1 shows a case where the product of the difference between the left and right vehicle heights 12a at the rear is negative, and the condition of [Equation 3] is that the left and right vehicle heights 12a at the rear of the vehicle 1 detected by the rear vehicle height sensor 12 and the reference The case where the absolute value of the difference from the vehicle height is less than or equal to a preset second threshold value ΔR0 is shown, and the condition of [Expression 1] and [Expression 2], or [Expression 1] and [Expression 3] If the condition is satisfied, it is determined that the vehicle 1 is on a wavy road, Set the undulating road flag to 1.

  If [Equation 1] and [Equation 2], or [Equation 1] and [Equation 3] are not satisfied, it is determined that the vehicle 1 is not on an undulating road, and an undulating road is obtained in step S4. Reset the flag to zero.

  Incidentally, the first threshold value ΔF0 can be set to 78 [mm], for example, but is not limited to this value, and may be appropriately selected from the range of 20 to 150 [mm].

  The second threshold value ΔR0 can be set to 5 [mm], for example, but is not limited to this value, and may be appropriately selected from a range of 0 to 40 [mm].

  It should be noted that the road surface where the front wheel 2 of the vehicle 1 touches the road surface has almost no difference in height, and the road surface where the rear wheel 3 of the vehicle 1 touches the road surface has a significant difference in height. However, it can be said that the road is a wavy road, but if such conditions are added to the determination of the wavy road, control interference may occur. Comparison with the threshold value is not performed.

  In parallel with the determination of the wavy road, as shown in FIG. 2, in the normal mode, in step S5, it is determined whether or not the average value of the left and right vehicle heights 11a in the front portion of the vehicle 1 is within the reference range. And whether the left and right vehicle heights 12a in the rear part of the vehicle 1 are within the reference range, and if both are within the reference range, the same determination is repeated as it is, but either Is not within the reference range, it is determined in step S6 whether or not the swell road flag is 0. If the swell road flag is 0, that is, if the vehicle 1 is not on the swell road, step S6 is performed. In S7, control is performed so that the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 falls within a reference range, and the left and right vehicle heights 12a at the rear portion of the vehicle 1 are controlled. Performing leveling control to fit reference range.

  On the other hand, when the wavy road flag is not 0, that is, when the vehicle 1 is on a wavy road, in step S8, control is performed so that the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 is within the reference range. The leveling control of the left and right vehicle heights 12a at the rear of the vehicle 1 is forcibly stopped.

  Further, in parallel with the determination of the undulating road, as shown in FIG. 3, during the normal mode, in step S9, it is detected whether or not the crouching switch 14 has been turned ON by the driver. If the driver does not turn on, the determination is repeated. On the other hand, if the crouching switch 14 is turned on by the driver, the swell flag is 0 in step S10. When the wavy road flag is 0, that is, when the vehicle 1 is not on the wavy road, in step S11, the average value of the left and right vehicle heights 11a at the front of the vehicle 1 is the reference range for crouching control. And the left and right vehicle heights 12a at the rear of the vehicle 1 are Leveling control is performed so as to be within a sub-range, and passengers can easily get on and off in a state where the average value of the left and right vehicle heights 11a in the front portion of the vehicle 1 is held in the reference range for crouching control. In S12, it is detected whether or not the crouching switch 14 has been turned off by the driver. If the crouching switch 14 has been turned off by the driver, the crouching control is terminated in step S13, and the front of the vehicle 1 is The vehicle height 11a is returned to the original position, and the process returns to step S9.

  On the other hand, when the wavy road flag is not 0, that is, when the vehicle 1 is on a wavy road, in step S14, the crouching control is performed so that the average value of the left and right vehicle heights 11a in the front portion of the vehicle 1 falls within the reference range for crouching control. The leveling control of the left and right vehicle heights 12a at the rear portion of the vehicle 1 is forcibly stopped and is continued, and in step S15, the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 is determined. The left and right vehicle heights 12a at the rear portion of the vehicle 1 at the time when they fall within the reference range for crouching control are stored. In step S16, the left and right vehicle heights 12a at the rear portion of the vehicle 1 are held at the stored values, respectively. With the average value of the left and right vehicle heights 11a at the front of the vehicle 1 kept in the reference range for crouching control Passengers can easily get on and off, and thereafter, in step S12, it is detected whether or not the crouching switch 14 has been turned off by the driver. If the crouching switch 14 has been turned off by the driver, In S13, the crouching control is terminated, the vehicle height 11a at the front portion of the vehicle 1 is returned to the original position, and the process returns to the step S9.

  With the configuration as described above, during the normal mode in step S1 of FIG. 1, for example, on an uphill road, as shown in FIG. The absolute value of the difference between the left and right vehicle heights 11a at the front of the vehicle 1 detected by the front vehicle height sensor 11 is not less than a first threshold ΔF0 set in advance ([Equation 1 ], The height of the road surface on which the rear wheel 3 of the vehicle 1 contacts is lower on the right side as opposed to the front wheel 2 side, as shown in FIG. The product of the difference between the left and right vehicle heights 11a detected at the front of the vehicle 1 and the difference between the left and right vehicle heights 12a detected at the rear vehicle height sensor 12 is negative. 2])), in step S2 in FIG. Both 1 is determined to have the undulating road, undulating road flag is 1 is set in step S3.

  From this state, as shown in FIG. 3, when the crouching switch 14 is turned on by the driver in step S9 during the normal mode, whether or not the swell road flag is 0 in step S10. Therefore, since the wavy road flag is not 0 and the vehicle 1 is on a wavy road, the process proceeds to step S14, and the average value of the left and right vehicle heights 11a in the front portion of the vehicle 1 falls within the reference range for crouching control. Thus, the leveling control of the left and right vehicle heights 12a at the rear of the vehicle 1 is forcibly held while being stopped. Thus, when compressed air is discharged simultaneously from the left and right front air springs 4 at the front of the vehicle 1, the bump stopper built in the right front air spring 4 comes into contact with the upper surface plate of the front air spring 4. As a result, a rubber contact state is reached in which the vehicle can no longer contract in the height direction, and the compressed air is continuously discharged from the left front air spring 4, and the average value of the left and right vehicle heights 11a at the front of the vehicle 1 is still If it does not fall to the reference range for crouching control, the compressed air in the left front air spring 4 is almost lost, and the left front air spring 4 is further contracted by the stabilizer reaction force. Since the leveling control of the vehicle 1 has already been stopped, Compressed air is not supplied to or discharged from the right rear air spring 5 and leveling control may be performed so that the vehicle body is parallel to a right-downward road surface on which the rear wheel 3 of the vehicle 1 contacts the ground. There is no concern that the front wheel 2 on the left side of the vehicle 1 will be lifted.

  Subsequently, in step S15, the left and right vehicle heights 12a at the rear of the vehicle 1 at the time when the average value of the left and right vehicle heights 11a at the front of the vehicle 1 falls within the reference range for crouching control is stored. While the left and right vehicle heights 12a at the rear 1 are held at the stored values, the passengers get on and off in the state where the average value of the left and right vehicle heights 11a at the front of the vehicle 1 is held in the reference range for crouching control. It can be easily performed.

  Here, if the leveling control of the left and right vehicle heights 12a at the rear part of the vehicle 1 is only forcibly stopped, the passengers can move in and out of the vehicle to get on and off the vehicle 1 In this embodiment, the left and right vehicle heights 12a at the rear of the vehicle 1 at the time when the average value of the left and right vehicle heights 11a at the front of the vehicle 1 falls within the reference range for crouching control. Since the stored vehicle heights 12a on the left and right sides of the rear portion of the vehicle 1 are held at the stored values, the posture of the rear portion of the vehicle 1 is stable without change and is extremely effective.

  Thereafter, in step S12, it is detected whether or not the crouching switch 14 has been turned off by the driver. If the crouching switch 14 has been turned off by the driver, the crouching control is terminated in step S13, and the vehicle The front vehicle height 11a is returned to the original position, and the process returns to step S9.

  Further, for example, the height of the road surface on which the front wheels 2 on the left and right sides of the vehicle 1 are grounded is significantly higher than that of the left and right sides, that is, the left and right vehicles at the front of the vehicle 1 detected by the front vehicle height sensor 11. The absolute value of the difference of the height 11a is equal to or greater than a preset first threshold value ΔF0 (see [Equation 1]), and the height of the road surface on which the rear wheel 3 of the vehicle 1 touches is determined by the other of the left and right sides of the vehicle 1 The height difference between the right and left sides of the vehicle 1 detected by the rear vehicle height sensor 12 and the reference vehicle height is absolutely the same as the height of the road surface to which the front wheel 2 on the side contacts the ground. Even when the value is equal to or smaller than a preset second threshold value ΔR0 (see [Equation 3]), it is determined that the vehicle 1 is on a wavy road, and the left and right leveling controls at the rear of the vehicle 1 are forced. From this state because When the chucking control is performed and the compressed air is simultaneously discharged from the left and right front air springs 4 at the front of the vehicle 1, the bump stoppers built in the front air springs 4 on the left and right sides are connected to the front air springs. 4 is brought into a rubber contact state in which it cannot contact further in the height direction by contacting the upper surface plate 4, and the compressed air is further discharged from the front air spring 4 on the other side of the left and right sides. 1 Not only the vehicle height 11a on the left and right sides in the front part, but also the vehicle height 12a on the left and right sides in the rear part of the vehicle 1 is lowered. Compressed air is not supplied to the rear air spring on the rear side, and the average value of the left and right vehicle heights 11a at the front portion of the vehicle 1 is increased. Such is unavoidable, and only crouching control is reliably performed alone.

  As a result, it is avoided that crouching control and leveling control are alternately performed so that control does not converge, and the vertical movement of the vehicle body continues until all the compressed air in the air tank is consumed. In addition, the leveling control of the left and right vehicle heights 12a at the rear of the vehicle 1 is not forcibly stopped, but the average value of the left and right vehicle heights 11a at the front of the vehicle 1 is the reference range for crouching control. The left and right vehicle heights 12a at the rear part of the vehicle 1 at the time when the vehicle is within the vehicle are stored, and the left and right vehicle heights 12a at the rear part of the vehicle 1 are held at the stored values. There is no concern that the posture change at the rear part of the vehicle 1 will occur even if the vehicle gets on or off.

  Thus, even if the height of the road surface on which the front wheels of the vehicle 1 are in contact with the left and right is different, the right and left front wheels of the vehicle 1 can be prevented from floating and the crouching control can be performed reliably and the compression can be performed. Air consumption can be suppressed, and furthermore, posture change at the rear of the vehicle 1 due to passengers getting on and off can be reliably prevented.

  Note that the vehicle air suspension control device of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Front wheel 3 Rear wheel 4 Front air spring 5 Rear air spring 6 Air tank 8 Front vehicle height adjustment valve 8a Control signal 10 Rear vehicle height adjustment valve 10a Control signal 11 Front vehicle height sensor 11a Vehicle height 12 Rear vehicle height sensor 12a Vehicle High 13 Controller 14 Crouching switch

Claims (2)

A front air spring disposed to support a front wheel of the vehicle;
A rear air spring disposed to support the rear wheel of the vehicle;
A front vehicle height adjustment valve for supplying and discharging compressed air in an air tank to the front air spring;
A rear vehicle height adjustment valve for supplying and discharging compressed air in an air tank to the rear air spring;
A front vehicle height sensor for detecting left and right vehicle heights at the front of the vehicle;
A rear vehicle height sensor for detecting left and right vehicle heights at the rear of the vehicle;
By outputting control signals to the front vehicle height adjustment valve and the rear vehicle height adjustment valve based on the vehicle heights detected by the front vehicle height sensor and the rear vehicle height sensor, the vehicle heights at the left and right at the rear of the vehicle are set to a constant height. In addition, leveling control is performed to keep the vehicle body parallel to the axle, and when passengers get on and off, crouching control is performed to lower the vehicle height at the front of the vehicle where the entrance is provided. A vehicle air suspension control device comprising a controller for performing vehicle height adjustment control for raising and lowering the vehicle to a required height,
When it is determined that the vehicle is on a wavy road during the normal mode in which the crouching control and the vehicle height adjustment control are not performed, the left and right vehicle height leveling control at the rear of the vehicle is forcibly stopped. ,
Leveling control of the left and right vehicle heights at the rear of the vehicle When crouching control is performed in an inactive state, the left and right of the rear of the vehicle at the time when the average value of the left and right vehicle heights is within the reference range for crouching control A vehicle air suspension control device configured to store each vehicle height and to maintain the left and right vehicle heights at the rear of the vehicle at the stored values until the crouching control is completed.   The absolute value of the difference between the left and right vehicle heights at the front of the vehicle detected by the front vehicle height sensor is not less than a preset first threshold, and the left and right of the vehicle front at the front of the vehicle detected by the front vehicle height sensor. When the product of the difference between the vehicle height and the difference between the left and right vehicle heights detected at the rear vehicle height sensor is negative, or the left and right vehicle heights at the rear of the vehicle detected by the rear vehicle height sensor The vehicle air suspension control device according to claim 1, wherein the vehicle air suspension control device determines that the vehicle is on a wavy road when the absolute value of the difference between the vehicle and the reference vehicle height is equal to or less than a preset second threshold value.

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