JP2013132929A - 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 performing crouching control, capable of restraining consumption of compressed air, and capable of surely preventing even an attitudinal change in a vehicle rear part caused by getting on and off of a passenger, while preventing one of right and left front wheels of the vehicle from lifting, even if a height of a road surface for grounding the front wheel of the vehicle is different between the right and left.SOLUTION: A front right-left communicating valve 16 closed when a vehicle 1 exists in an undulated road, is arranged in the middle of a front communicating air pipe 15 for connecting right-left front air springs 4, and a rear right-left communicating valve 18 opened when the vehicle 1 exists in an undulated road, is arranged in the middle of a rear communicating air pipe 17 for connecting right-left rear air springs 5. In the crouching control in the undulated road, vehicle heights 11a of the respective right and left in a front part of the vehicle 1, are made to fall within a reference range for the crouching control, and an average value of right-left vehicle heights 12a in a rear part of the vehicle 1 are made to fall within the reference range.

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. 5 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. 6A, 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, and the rear wheel 3 of the vehicle 1 is As shown in FIG. 6B, the height of the road surface to be contacted is a “swell road” in which 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, Since 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.

  Also, for example, as shown in FIG. 6A, 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 left and right front air springs arranged to support a front wheel of a vehicle,
Left and right rear air springs arranged to support the rear wheels 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,
The front left and right air pipes connecting the left and right front air springs are opened when it is determined that the vehicle is not on a wavy road and closed when the vehicle is determined to be on a wavy road When a communication valve is provided and the rear communication air pipe connecting the left and right rear air springs is closed when it is determined that the vehicle is not on a wavy road and when the vehicle is determined to be on a wavy road The rear left and right communication valves are opened,
During crouching control on a wavy road, the left and right vehicle heights at the front of the vehicle are within the reference range for crouching control, and the average value of the left and right vehicle heights at the rear of the vehicle is within the reference range. The vehicle air suspension control device is as follows.

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

  When configured as described above, when it is determined that the vehicle is on a wavy road, the front left and right communication valves are closed during crouching control so that the left and right vehicle heights at the front of the vehicle are within the reference range for crouching control. Crofting control is performed, and vehicle rear left / right average value control is performed in which the rear left / right communication valve is opened and the average value of the left and right vehicle heights in the rear of the vehicle falls within a reference range. As a result, when compressed air is discharged from the left and right front air springs at the front of the vehicle 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. Before falling into a rubber contact state in which the vehicle can no longer contract in the height direction, the vehicle height on one of the left and right sides at the front of the vehicle falls within the reference range for crouching control, and the compression in the front air spring on the other side Before the air runs out, the vehicle height on the left and right sides at the front of the vehicle will also fall within the reference range for crouching control, and the front air spring on the other side will be further contracted by the stabilizer reaction force. Furthermore, the rear left and right communication valves are opened, and the average of the left and right vehicle heights at the rear of the vehicle Therefore, the left and right rear air spring pressure at the rear of the vehicle is constant by communication, and the average value of the left and right vehicle heights at the rear of the vehicle is used as the reference range. Since only compressed air is supplied and discharged to accommodate the leveling control, it is possible to avoid leveling control so that the vehicle body is parallel to the road surface on which one of the left and right sides where the rear wheel of the vehicle touches is lowered. There is no worry that the front wheels on the other side of the vehicle will float up.

  And while the average value of the left and right vehicle heights in the rear part of the vehicle is maintained in the reference range, the passenger can easily get on and off in a state where the left and right vehicle heights in the front part of the vehicle are maintained in the reference range for crouching control. It becomes possible.

  Here, if the leveling control of the left and right vehicle heights at the rear part of the vehicle is forcibly stopped, the posture change at the rear part of the vehicle may occur due to the passenger moving in or out of the vehicle to get on and off. However, in the present invention, since the vehicle rear left and right average value control is performed so that the average value of the left and right vehicle heights in the rear of the vehicle falls within a reference range, the posture at the rear of the vehicle is stable without changing. Will be very effective.

  As a result, it is avoided that the crouching control and the leveling control are alternately performed so that the control does not converge, and the vertical movement of the vehicle body continues until all the compressed air in the air tank 6 is consumed. Unlike the case where the leveling control of the left and right vehicle heights at the rear part of the vehicle is merely forcibly stopped, the rear left and right communication valves are opened and the average of the left and right vehicle heights at the rear part of the vehicle is eliminated. Since the vehicle rear left and right average value control that keeps the value within the reference range is performed, even if the passenger moves inside the vehicle or gets on and off itself, there is a concern that the posture change at the rear of the vehicle will occur Not at all.

  When it is determined that the vehicle is not on a wavy road, the front left and right communication valves are opened to control the average value of the left and right vehicle heights at the front of the vehicle within the reference range, and the rear left and right It is possible to perform leveling control so that the left and right vehicle heights in the rear part of the vehicle are within the reference range by closing the communication valve, and the tilt of the vehicle can be corrected on the rear axle side with a large axle load and wide tread. This is effective in improving running stability.

  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.

1 is an overall schematic configuration diagram showing an embodiment of a vehicle air suspension control device of the present invention. It is a flowchart which shows the waviness determination in the Example of the air suspension control apparatus for vehicles of this invention. In the embodiment of the vehicle air suspension control device of the present invention, when the vehicle is on a wavy road, the front left and right communication valves are closed to perform level control of the vehicle front left and right respectively, and the rear left and right It is a flowchart which shows the condition where a communicating valve is opened and vehicle rear left and right vehicle height average value control is performed. In the embodiment of the vehicle air suspension control device of the present invention, when crouching control is performed when the vehicle is on a wavy road, the front left and right communication valves are closed and the vehicle height crouching control of the vehicle left and right respectively. 5 is a flowchart showing a situation where the rear left / right communication valve is opened and the vehicle rear left / right vehicle height average value control is performed. 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.

  1 to 4 show an embodiment of a vehicle air suspension control apparatus according to the present invention. In the figure, the same reference numerals as those in FIGS. 5 and 6 is the same as that of the prior art shown in FIGS. 5 and 6, but the feature of this embodiment is that the front communicating air line connecting the left and right front air springs 4 as shown in FIGS. 15 is provided with a front left and right communication valve 16 that is opened when it is determined that the vehicle 1 is not on a wavy road and is closed when it is determined that the vehicle 1 is on a wavy road. A rear left and right communication valve 18 that is closed when it is determined that the vehicle 1 is not on a wavy road and is opened when it is determined that the vehicle 1 is on a wavy road in the middle of the rear communication air pipe 17 that connects the spring 5. In the swell road At the time of the routing control, the left and right vehicle heights 11a at the front portion of the vehicle 1 are within the reference range for crouching control, and the average value of the left and right vehicle heights 12a at the rear portion of the vehicle 1 is within the reference range. .

  The front left / right communication valve 16 is opened / closed by a control signal 16 a from the controller 13, and the rear left / right communication valve 18 is opened / closed by a control signal 18 a from the controller 13.

  First, in step S1 of FIGS. 2 to 4, 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 of FIG. 2, it is determined whether or not the vehicle 1 is on a wavy road, for example, as shown in FIG. 6A, 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. 6 (b). For example, as shown in FIG. 6A, 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 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. 1) is equal to or greater than a preset first threshold value ΔF0. The condition of [Expression 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. 1). 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 detected at 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, and the process goes to step S3. 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. 3, in the normal mode, in step S5, it is determined whether or not the average value of the left and right vehicle heights 11a at 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. When the sway road flag is 0, that is, when the vehicle 1 is not on the swell road, In step 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 12 at the rear portion of the vehicle 1 are controlled. There performing leveling control to fit reference range. At this time, the front left / right communication valve 16 is open, and the rear left / right communication valve 18 is closed.

  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, the front left and right communication valves 16 are closed and the left and right vehicle heights 11a at the front of the vehicle 1 are used as the reference. Leveling control is performed so as to be within the range, and vehicle rear left / right average value control is performed so that the average value of the left and right vehicle heights 12a at the rear of the vehicle 1 falls within a reference range by opening the rear left / right communication valve 18.

  Further, in parallel with the determination of the undulating road, as shown in FIG. 4, during the normal mode, it is detected in step S9 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 undulation flag is 0, that is, when the vehicle 1 is not on the undulation, in step S11, the front left / right communication valve 16 is opened and the left and right vehicles in the front of the vehicle 1 are opened. Crouching control is performed so that the average value of the height 11a falls within the reference range for crouching control. Leveling control is performed so that the left and right vehicle heights 12a in the rear part of the vehicle 1 are within the reference range with the valve 18 closed, and the average value of the left and right vehicle heights 11a in the front part of the vehicle 1 is determined as a reference range for crouching control. In step S12, it is detected whether or not the crouching switch 14 has been turned off by the driver, and the crouching switch 14 is turned off by the driver. If this is the case, the crouching control is terminated in step S13, the vehicle height 11a at the front of the vehicle 1 is restored, 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 front left / right communication valve 16 is closed and the left and right vehicle heights 11a at the front of the vehicle 1 are crouched. The crouching control is performed so as to be within the control reference range, the rear left / right communication valve 18 is opened, and the rear left / right average value control is performed so that the average value of the left and right vehicle heights 12a at the rear of the vehicle 1 falls within the reference range. Whether or not the passenger can easily get on and off with the left and right vehicle heights 11a in the front part of the vehicle 1 kept within the reference range for crouching control, and then, in step S12, whether the crouching switch 14 has been turned OFF by the driver. The crouching switch 14 is turned off by the driver. Expediently, it ends the crouching control in step S13, to undo the vehicle 1 front portion of the vehicle height 11a, so that the flow returns to step S9.

  When configured as described above, during the normal mode in step S1 of FIG. 2, for example, on an uphill road, as shown in FIG. 6A, the height of the road surface on which the front wheel 2 on the right side of the vehicle 1 contacts the ground The absolute value of the difference between the left and right vehicle heights 11a at the front portion 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]). As shown in FIG. 6B, 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, that is, detected by the front vehicle height sensor 11. The product of the difference between the left and right vehicle heights 11a at the front of the vehicle 1 and the difference between the left and right vehicle heights 12a detected by the rear vehicle height sensor 12 is negative ([Equation 2] In such a case, the vehicle in step S2 in FIG. There is judged being in undulating road, undulating road flag is 1 is set in step S3.

  From this state, as shown in FIG. 4, 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. Since the undulation road flag is not 0 and the vehicle 1 is on the undulation road, the process proceeds to step S14 where the front left / right communication valve 16 is closed and the left and right vehicle heights at the front of the vehicle 1 are closed. 11a is controlled so as to be within the reference range for crouching control, and the rear left / right communication valve 18 is opened, and the average value of the left and right vehicle heights 12a at the rear of the vehicle 1 falls within the reference range. Control is performed. 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. The vehicle height 11a on the right side of the front portion of the vehicle 1 falls within the reference range for crouching control and the compressed air in the left front air spring 4 is compressed before falling into a rubber contact state where the vehicle can no longer contract in the height direction. Before it disappears, the left vehicle height 11a at the front of the vehicle 1 is also within the reference range for crouching control, and it is avoided that the left front air spring 4 is further contracted by the stabilizer reaction force. The rear left / right communication valve 18 is opened and the average of the left and right vehicle heights 12a at the rear of the vehicle 1 is determined. Therefore, the pressure of the left and right rear air springs 5 at the rear of the vehicle 1 is constant due to the communication, and the average value of the left and right vehicle heights 12a at the rear of the vehicle 1 is controlled. Since the compressed air is only supplied and discharged so as to be within the reference range, the leveling control may be 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. There is no concern that the front wheel 2 on the left side of the vehicle 1 will be lifted.

  Then, while the average value of the left and right vehicle heights 12a at the rear part of the vehicle 1 is held in the reference range, the passengers get on and off in a state where the left and right vehicle heights 11a at the front part of the vehicle 1 are held in the reference range for crouching control. Can be easily performed.

  Here, if the leveling control of the left and right vehicle heights 12a at the rear of the vehicle 1 is forcibly stopped, the passenger 1 moves in the vehicle to get on and off, or gets on and off the vehicle 1 at the rear of the vehicle 1 In this embodiment, since the vehicle rear left / right average value control is performed so that the average value of the left and right vehicle heights 12a in the rear portion of the vehicle 1 falls within a reference range, the posture in the rear portion of the vehicle 1 is changed. Is stable without change and is very 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 on the left and right sides, that is, the left and right vehicle heights at the front of the vehicle 1 detected by the front vehicle height sensor 11. The absolute value of the difference of 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 contacts the other side of the vehicle 1 There is almost no difference in height on the left and right, which is equal to the height of the road surface on which the front wheel 2 contacts the ground, that is, the absolute value of the difference between the left and right vehicle heights 12a detected by the rear vehicle height sensor 12 and the reference vehicle height is Also in the case where the second threshold value ΔR0 is less than or equal to the preset second threshold value ΔR0 (see [Equation 3]), it is determined that the vehicle 1 is on the undulating road, and crouching control is performed from this state, The left and right front air springs 4 When the air stopper 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 falls into a rubber contact state where it cannot contract further in the height direction. The right vehicle height 11a at the front of the vehicle 1 falls within the reference range for crouching control, and the left vehicle height 11a at the front of the vehicle 1 is also crouched before the compressed air in the left front air spring 4 runs out. The left front air spring 4 is prevented from being further contracted by the stabilizer reaction force, and the vehicle 1 is tilted to the left side in accordance with the operation of the crouching control. However, the pressure of the left and right rear air springs 5 at the rear of the vehicle 1 is constant due to the communication, The compressed air is not supplied only to the left rear air spring at the rear of the vehicle 1 because the compressed air is only supplied and discharged so that the average value of the left and right vehicle heights 12a falls within the reference range. It can be avoided that the vehicle height 11a on the left side in the front portion of the vehicle 1 becomes high.

  As a result, it is avoided that the crouching control and the leveling control are alternately performed so that the control does not converge, and the vertical movement of the vehicle body continues until all the compressed air in the air tank 6 is consumed. Unlike the case where the leveling control of the left and right vehicle heights 12a at the rear portion of the vehicle 1 is forcibly stopped, the rear left and right communication valves 18 are opened and the left and right portions at the rear portion of the vehicle 1 are opened. Since the vehicle rear left / right average value control that keeps the average value of the vehicle height 12a within the reference range is performed, even if the passenger moves in or gets out of the vehicle to get on and off, the posture change at the rear of the vehicle 1 There is no worry that will occur.

  When it is determined that the vehicle 1 is not on a wavy road, the front left / right communication valve 16 is opened, and control is performed so that the average value of the left and right vehicle heights 11a at the front of the vehicle 1 falls within a reference range. At the same time, the rear left and right communication valves 18 are closed to enable leveling control so that the left and right vehicle heights 12a at the rear of the vehicle 1 are within the reference range, and the rear axle has a large axial load and a wide tread. Since the inclination of the vehicle 1 can be corrected on the side, it is effective in improving the running stability.

  In this way, even if the height of the road surface on which the front wheel 2 of the vehicle 1 is in contact with the left and right is different, the right and left front wheels 2 of the vehicle 1 can be prevented from floating and the crouching control can be performed reliably. In addition, consumption of compressed air 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 15 Front communication air line 16 Front left and right communication valve 17 Rear communication air line 18 Rear left and right communication valve

Claims (2)

Left and right front air springs arranged to support the front wheels of the vehicle;
Left and right rear air springs arranged to support the rear wheels 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,
The front left and right air pipes connecting the left and right front air springs are opened when it is determined that the vehicle is not on a wavy road and closed when the vehicle is determined to be on a wavy road When a communication valve is provided and the rear communication air pipe connecting the left and right rear air springs is closed when it is determined that the vehicle is not on a wavy road and when the vehicle is determined to be on a wavy road The rear left and right communication valves are opened,
During crouching control on a wavy road, the left and right vehicle heights at the front of the vehicle are within the reference range for crouching control, and the average value of the left and right vehicle heights at the rear of the vehicle is within the reference range. A vehicle air suspension control device.   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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