JP2017171185A - Vehicle height adjustment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle height adjustment device which can efficiently avoid a stack.SOLUTION: A vehicle height adjustment device comprises slip wheel detection means for detecting a slipped wheel being a wheel at which a slip has occurred, and vehicle height adjustment means for adjusting a vehicle height of a vehicle main body by changing relative positions of wheels and the vehicle main body. When the slipped wheel is detected by the slip wheel detection means, the vehicle height adjustment means adjusts a vehicle height at a portion corresponding to a position of a wheel other than the slipped wheel so that a grounding load of the slipped wheel becomes large.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a vehicle height adjusting device.

  Patent Document 1 discloses a vehicle suspension device that adjusts the ground load according to the state of each wheel. In the vehicle suspension apparatus of Patent Document 1, an absorber that can change the ground load using a motor is provided in a plurality of wheels. When slip occurs in at least one of the plurality of wheels, the motor is driven so as to increase the ground contact load of the wheels other than the wheel in which the slip has occurred. The motor is driven for a predetermined time, and the ground load of the wheel where the slip has occurred is distributed to the other wheels.

  Patent Document 2 discloses a vehicle control device that appropriately transmits a driving force of a vehicle to a road surface. In the vehicle control device of Patent Document 2, ungrounded wheel detection means for detecting ungrounded wheels that are wheels that are not properly grounded on the road surface, and an upward or downward inertial force on the vehicle portion around the wheels. Inertial force means for generating is provided. When ungrounded wheels that are not installed on the road surface are detected and two ungrounded wheels located at diagonal positions are detected, a downward inertia force is generated on one ungrounded wheel at substantially the same timing. Then, by generating an upward inertia force on the other ungrounded wheel, the wheel is swung and the slip wheel is grounded on the road surface.

Japanese Patent No. 4125197 Japanese Patent No. 4788470

  In Patent Document 1, the ground load is distributed to wheels other than the slipped wheel. For example, when a vehicle equipped with a differential (differential device) gets stuck on a muddy or frozen road surface and the left side of the front wheel slips, the ground load is transferred to the remaining right side of the front wheel and the left and right rear wheels. Since the differential distributes the torque to the wheels with less resistance, the driving force is lost to the left side of the front wheel that is slipping and spinning. Therefore, since the driving force for the front wheels is lost, the driving force is reduced to substantially the driving force for the two rear wheels, so that it may take time to avoid the stack or it may not be avoided.

  Patent Document 2 is premised on the existence of two diagonal non-ground wheels in order to swing the vehicle. In addition, energy is consumed to swing the vehicle, and stacking cannot be efficiently avoided.

  In view of the above-described problems, an object of the present invention is to provide a vehicle height adjusting device that can efficiently avoid stacking.

  A vehicle height adjustment device according to an aspect of the present invention includes a slip wheel detection unit that detects a slip wheel that is a wheel in which a slip has occurred, and a relative position between each wheel and the vehicle body, thereby changing the vehicle body. Vehicle height adjusting means for adjusting the vehicle height of the vehicle, the vehicle height adjusting means so that, when the slip wheel is detected by the slip wheel detecting means, the ground load of the slip wheel is increased. The vehicle height of the portion corresponding to the position of the wheel other than the slip wheel is adjusted.

  According to such a configuration, when a slip occurs in any of the wheels, the slip wheel detection means detects the slip wheel, and the vehicle height adjustment means causes a wheel other than the slip wheel so that the ground load of the slip wheel increases. Adjust the height of the part corresponding to the position of. Thereby, a slip wheel can be appropriately grounded on a road surface. Therefore, a decrease in the driving force of the vehicle due to the slip can be avoided, and the driving force of the slip wheel can be increased. Therefore, the driving force of the wheels can be properly transmitted to the road surface. Therefore, stacking can be avoided efficiently.

  The vehicle height adjusting device further includes slope determining means for determining whether or not the vehicle is traveling on a slope, wherein the vehicle height adjusting means adjusts the vehicle height using an air suspension system, and the slope determining means The part corresponding to the position of the wheel other than the slip wheel so that the ground load of the slip wheel is increased when the vehicle is traveling on the slope and the slip wheel is detected by the slip wheel detecting means. The vehicle height may be adjusted.

  According to such a configuration, in the air suspension system, to adjust the vehicle height of the vehicle body by changing the relative position of each wheel and the vehicle body by supplying and discharging the air in the air spring, Compared to a metal spring, the spring characteristics can be selected relatively freely. Therefore, the air suspension system obtains a lower spring constant than the suspension system using a metal spring and is in a soft state. For this reason, when a vehicle using an air suspension system travels on an uphill slope, for example, the rear wheels easily sink and the front wheels float, so the front wheels easily slip. Accordingly, when the vehicle is traveling on the slope and the slip wheel detection means detects the slip wheel, the vehicle height adjustment means sets the ground load of the slip wheel to a position other than the slip wheel when the vehicle is traveling on the slope. Adjust the height of the corresponding part. As a result, a decrease in the driving force of the vehicle due to the slip is avoided, and the driving force of the slip wheel can be increased. Therefore, since the driving force of the wheels can be properly transmitted to the road surface even when the vehicle using the air suspension system is traveling on a slope, stacking can be efficiently avoided.

  In the vehicle height adjusting device, the slip wheel detecting means may include first slip wheel estimating means for detecting a slip wheel based on wheel acceleration.

  According to such a configuration, when a slip occurs on any of the wheels, the slip wheel can be easily detected by detecting the slip wheel based on the wheel acceleration.

  In the vehicle height adjusting device, the slip wheel detecting means further includes second slip wheel estimating means for detecting a slip wheel based on the inclination of the vehicle, and the first slip wheel estimating means and the second slip wheel estimating means. When the slip wheels estimated by the means are the same, the estimated slip wheel may be determined as the slip wheel.

  According to such a configuration, when a slip occurs in any of the wheels, the slip wheel is estimated by estimating the slip wheel in double by the estimation by the first slip wheel estimation means and the estimation by the second slip wheel estimation means. Can be reliably detected.

  In the vehicle height adjusting device, the vehicle is a two-wheel drive system, and the first slip wheel detecting means detects the slip wheel by comparing the wheel acceleration of each wheel of the drive wheel and the wheel acceleration of the driven wheel. It is good.

  According to such a configuration, when the vehicle is a two-wheel drive system, the occurrence of slip in the drive wheels that generate drive force becomes a problem. The wheel acceleration of the driven wheel is almost the same as the acceleration of the vehicle body. Further, when the acceleration of the driving wheel is faster than the acceleration of the vehicle body, it can be said that the driving wheel has slipped. Therefore, the slip wheel can be easily detected by comparing the wheel accelerations of the driving wheels and the driven wheels.

  The vehicle height adjusting device further includes slip cancellation determining means for determining whether or not the vehicle slip state is in a normal running state, and the vehicle height adjusting means is in a normal traveling state by the slip canceling means. The vehicle height adjustment may be continued until it is determined.

  According to such a configuration, the adjustment of the vehicle height of the portion corresponding to the position of the wheel other than the slip wheel can be repeated so that the ground load of the slip wheel increases until the slip is eliminated. . Therefore, the driving force of the slip wheel can be reliably and quickly increased.

  ADVANTAGE OF THE INVENTION According to this invention, the vehicle height adjustment apparatus which can avoid a stack | stuck efficiently can be provided.

The block diagram of the vehicle height adjustment apparatus which concerns on one Embodiment of this invention. The flowchart figure which shows the operation | movement procedure which concerns on this invention. The block diagram of the air suspension system which concerns on this invention. The block diagram of the air suspension system in the case of raising vehicle height, without operating the compressor which concerns on this invention. The block diagram of the air suspension system in the case of operating the compressor which concerns on this invention and raising vehicle height. The block diagram of the air suspension system in the case of reducing the vehicle height which concerns on this invention.

  Hereinafter, an embodiment of the vehicle height adjusting device will be described. A vehicle including an embodiment of the vehicle height adjusting device is a two-wheel drive system.

  FIG. 1 shows a configuration of a vehicle height adjusting device according to an embodiment of the present invention. The vehicle height adjusting device includes a vehicle height sensor 10, a wheel speed sensor 11, a longitudinal / lateral acceleration sensor 12, an air suspension system 13, and an electronic control unit (hereinafter referred to as an ECU 14). The ECU 14 includes an inclination detection unit 20, a slope determination unit 21, a slip wheel detection unit 22, a vehicle height adjustment unit 25, and a slip elimination determination unit 26. The slip wheel detection means 22 includes a first slip wheel estimation means 23 and a second slip wheel estimation means 24.

  The vehicle height sensor 10 is provided corresponding to each wheel, and detects the vehicle height by detecting the movement of the suspension. The wheel speed sensor 11 is provided corresponding to each wheel, and detects the wheel speed based on the rotational speed of each wheel. The longitudinal / lateral acceleration sensor 12 is provided in the vehicle and detects longitudinal / lateral acceleration of the vehicle. The vehicle height sensor 10, the wheel speed sensor 11, and the longitudinal / lateral acceleration sensor 12 are connected to the ECU 14, and the detection results of the sensors are output to the ECU 14.

  The inclination detection means 20 detects the inclination of the vehicle from the detection result of the longitudinal / lateral acceleration sensor 12. The slope judgment means 21 judges whether or not the vehicle is traveling on the slope based on the vehicle inclination detected by the inclination detection means 20.

  The vehicle includes an air suspension system 13. Since the air suspension system 13 adjusts the vehicle height by supplying and discharging the air in the air spring 30, the characteristics of the spring can be selected relatively freely as compared with the metal spring. Therefore, the air suspension system 13 obtains a lower spring constant than the suspension system using a metal spring, and is in a soft state. For this reason, when the vehicle on which the air suspension system 13 is mounted travels on an uphill slope, the front wheels easily slip because the rear wheels easily sink and the front wheels float. Further, when traveling on a downhill slope, the front wheels tend to sink and the rear wheels float, so the rear wheels tend to slip. Therefore, in the present embodiment, an example will be described in which the slope determination unit 21 determines that the vehicle is traveling on a slope. First, when the slope detection means determines that the vehicle is traveling on a slope, the operation procedure shown in FIG. 2 is started. FIG. 2 is a flowchart showing an operation procedure according to the present invention.

  First, the ECU 14 calculates the acceleration of each wheel by differentiating the wheel speed obtained from the wheel speed sensor 11 with respect to time (S11). Next, the first slip estimating means 23 of the slip wheel detecting means 22 estimates the slip wheel by comparing the acceleration of each wheel of the driving wheel and the acceleration of the driven wheel (S12). Since the acceleration of the driven wheel is substantially equal to the acceleration of the vehicle body, if the acceleration of the driving wheel is faster than the acceleration of the driven wheel, the corresponding wheel is estimated as a slip wheel. Therefore, the first slip estimation means 23 determines that a slip has occurred when the value of (wheel acceleration of the drive wheel−wheel acceleration of the driven wheel) exceeds the slip determination threshold for each drive wheel. Drive wheels that exceed the limit are estimated as slip wheels. When the slip wheel is not detected by the first slip estimation means 23, the ECU 14 determines that no slip has occurred, and ends the processing in this flowchart.

  Next, the inclination detecting means 20 detects the inclination of the vehicle from the detection result of the longitudinal / lateral acceleration sensor 12 (S13). And the 2nd slip estimation means 24 of the slip wheel detection means 22 estimates a slip wheel based on the inclination of a vehicle (S14). When the vehicle leans, there are wheels that are not properly in contact with the road surface. Therefore, the slip wheel can be estimated based on the inclination of the vehicle.

  Based on the slip wheels estimated by the first slip wheel estimation means 23 and the second slip wheel estimation means 24, the slip wheel detection means 22 determines a slip wheel (S15). If the estimated slip wheels are the same, the slip wheel detection means 22 determines that the corresponding wheel is a slip wheel. When a slip occurs in any of the wheels, the slip wheel is reliably detected by estimating the slip wheel in double by the estimation by the first slip wheel estimation means 22 and the estimation by the second slip wheel estimation means 23. be able to. If the slip wheel is not detected by the slip wheel detection means 22, the ECU 14 determines that no slip has occurred and ends the processing in this flowchart.

  The vehicle height adjusting means 25 adjusts the vehicle height of the vehicle main body by changing the relative positions of the wheels and the vehicle main body. When the slip wheel is detected by the slip wheel detection means 22, the vehicle height adjustment means 25 adjusts the vehicle height of the portion corresponding to the position of the wheel other than the slip wheel so that the ground load of the slip wheel is increased (S16). ).

  FIG. 3 is a configuration diagram of the air suspension system 13. The air suspension system 13 includes air springs 30a and 30b, valves 31a to 31g, a tank 32, a pressure sensor 33, a compressor and motor 34, a dryer 35, a filter 36, and a tube 37. Air compressed by the compressor & motor 34 is stored in the tank 32. The compressed air is supplied into the air spring 30 by opening the valve 31. Based on the detection result of the vehicle height sensor 10, the air suspension system 13 supplies air into the air spring 30 to raise the vehicle height if the vehicle height is lower than the target vehicle height, and in the air spring 30 if the vehicle height is higher than the target vehicle height. The vehicle height is adjusted by discharging the air and lowering the vehicle height. The air suspension system 13 increases or decreases the vehicle height of the portion corresponding to the position of the wheel other than the slip wheel so that the ground load of the slip wheel increases. For example, when the left side of the front wheel slips, the vehicle height of the part corresponding to the positions of the right side of the front wheel and the left and right rear wheels is adjusted.

  Hereinafter, the vehicle height control of the air suspension system 13 will be schematically described with reference to FIGS. 4 to 6. Control for increasing the vehicle height of the air suspension system 13 may be performed when the compressor & motor 34 is operated as shown in FIGS. 4 and 6 or when the compressor & motor 34 is not operated as shown in FIG. 5.

  When the compressor & motor 34 shown in FIG. 4 is operated, the valves 31c and 31e are opened. The compressor & motor 34 draws in air from the tank 32 and discharges it to the air spring 30 side, thereby increasing the vehicle height. When the compressor & motor 34 shown in FIG. 5 is not operated, the valves 31c, 31d, 31e, and 31f are opened. The vehicle height is increased by moving the air only by the pressure difference without operating the compressor & motor 34.

  Control for reducing the vehicle height of the air suspension system 13 shown in FIG. 6 opens the valves 31d and 31f. The compressor & motor 34 draws air from the air spring 30 side and discharges it to the tank 32 to lower the vehicle height.

  The vehicle height adjusting means 25 uses the control of the air suspension system 13 as described above to adjust the vehicle height of the portion corresponding to the position of the wheel other than the slip wheel so that the ground load of the slip wheel is increased. As a result, a decrease in the driving force of the vehicle due to the slip is avoided, and the driving force of the slip wheel can be increased. Therefore, the driving force of the wheels can be properly transmitted to the road surface. Therefore, stacking can be avoided efficiently.

  The slip cancellation determination means 26 determines whether or not the vehicle is in a normal running state in which the slip state of the vehicle has been canceled based on the comparison result between the driven wheel speed obtained from the wheel speed sensor 11 and the normal determination threshold value (S17). . Until the slip is eliminated, the adjustment of the vehicle height of the portion corresponding to the position of the wheel other than the slip wheel can be repeated so that the ground contact load of the slip wheel is increased. Therefore, the driving force of the slip wheel can be reliably and quickly increased. If it is determined by the slip cancellation determination means 26 that the vehicle is in a normal running state in which the slip state has been canceled, the ECU 14 determines that no slip has occurred and ends the processing in this flowchart.

As described above in detail, according to the present embodiment, the following effects are obtained.
(1) According to the configuration of the vehicle height adjusting device according to the embodiment of the present invention described above, when a slip occurs in any of the wheels, the slip wheel detecting means 22 detects the slip wheel, and the vehicle height adjusting means 25 is detected. The vehicle height of the portion corresponding to the position of the wheel other than the slip wheel is adjusted so that the ground load of the slip wheel increases. Thereby, a slip wheel can be appropriately grounded on a road surface. Therefore, a decrease in the driving force of the vehicle due to the slip can be avoided, and the driving force of the slip wheel can be increased. Therefore, the driving force of the wheels can be properly transmitted to the road surface. Therefore, stacking can be avoided efficiently.
(2) According to the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, the air suspension system 13 supplies and discharges the air in the air spring 30 so that each wheel and the vehicle main body are relative to each other. Since the vehicle height of the vehicle body is adjusted by changing the position, the characteristics of the spring can be selected relatively freely as compared with the metal spring. Therefore, the air suspension system 13 obtains a lower spring constant than the suspension system using a metal spring, and is in a soft state. For this reason, when the vehicle using the air suspension system 13 is traveling on an uphill slope, for example, the rear wheels easily sink and the front wheels float, and thus the front wheels easily slip. Therefore, when the slope judgment means 21 is traveling on the slope and the slip wheel detection means 22 detects the slip wheel, wheels other than the slip wheels are adjusted so that the ground load of the slip wheel is increased by the vehicle height adjustment means 25. Adjust the height of the part corresponding to the position of. As a result, a decrease in the driving force of the vehicle due to the slip is avoided, and the driving force of the slip wheel can be increased. Therefore, even when the vehicle using the air suspension system 13 is traveling on a slope, the driving force of wheels can be appropriately transmitted to the road surface, so that stacking can be efficiently avoided.
(3) According to the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, when slip occurs in any of the wheels, the slip wheel is easily detected by detecting the slip wheel based on the wheel acceleration. Can be detected.
(4) According to the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, when slip occurs in any of the wheels, the estimation by the first slip wheel estimation unit 23 and the second slip wheel estimation unit 24 are performed. The slip wheel can be reliably detected by estimating the slip wheel by double estimation.
(5) According to the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, when the vehicle is of the two-wheel drive system, the occurrence of slip in the driving wheel that generates the driving force becomes a problem. The wheel acceleration of the driven wheel is almost the same as the acceleration of the vehicle body. Further, when the acceleration of the driving wheel is faster than the acceleration of the vehicle body, it can be said that the driving wheel has slipped. Therefore, the slip wheel can be easily detected by comparing the wheel accelerations of the driving wheels and the driven wheels.
(6) According to the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, the position of the wheels other than the slip wheel is set so that the ground load of the slip wheel is increased until the slip is eliminated. The adjustment of the vehicle height of the part corresponding to can be repeated. Therefore, the driving force of the slip wheel can be reliably and quickly increased.
(Other embodiments)
In the above-described embodiment, it has been described that the slip wheel detection means 22 includes the first slip wheel estimation means 23 and the second slip wheel estimation means 24, but the present invention is not limited to this. The slip wheel detection means 22 may include only the first slip wheel estimation means 23.

  In the above-described embodiment, the vehicle height adjusting means 25 adjusts the vehicle height of the vehicle body by changing the relative positions of the wheels and the vehicle body using the air suspension system 13. For example, other suspension systems such as a leaf spring type and a coil spring type may be used.

  In the above-described embodiment, the vehicle is a two-wheel drive system, but the present invention can also be applied to a four-wheel drive system. For example, in a four-wheel drive vehicle, even if the slip wheel is detected from the inclination of the vehicle and the vehicle height of the portion corresponding to the position of the wheel other than the slip wheel is adjusted so that the ground contact load of the slip wheel increases. Good.

  Further, in the above-described embodiment, the ECU 14 includes the slope determination means 21, and when the slope determination means 21 determines that the vehicle is traveling on the slope, it moves to the operation procedure shown in FIG. The invention is not limited to this. The ECU 14 may be a vehicle control device that does not include the slope detection means 21 and performs the operation procedure shown in FIG.

10: Vehicle height sensor 11: Wheel speed sensor 12: Longitudinal / lateral acceleration sensor 13: Air suspension system 14: ECU
20: Inclination detection means 21: Slope determination means 22: Slip wheel detection means 23: First slip wheel estimation means 24: Second slip wheel estimation means 25: Vehicle height adjustment means 26: Slip cancellation determination means 30: Air spring 30a: Fr Air spring 30b: Rr Air spring 31: Valve 31a: Fr valve 31b: Rr valve 31c: Valve 1
32d: Valve 2
31e: Valve 3
32f: Valve 4
32 g: exhaust valve 32: tank 33: pressure sensor 34: compressor & motor 35: dryer 36: filter 37: tube

Claims (6)

Slip wheel detecting means for detecting a slip wheel which is a wheel in which slip has occurred;
Vehicle height adjusting means for adjusting the vehicle height of the vehicle main body by changing the relative position of each wheel and the vehicle main body,
When the slip wheel is detected by the slip wheel detecting means, the vehicle height adjusting means has a vehicle height at a portion corresponding to the position of the wheel other than the slip wheel so that a ground load of the slip wheel is increased. Adjusting the vehicle height. Further comprising slope judging means for judging whether or not the vehicle is traveling on the slope;
The vehicle height adjusting means adjusts the vehicle height using an air suspension system,
The position of the wheels other than the slip wheel so that the ground load of the slip wheel is increased when the vehicle is traveling on the slope by the slope judgment unit and the slip wheel is detected by the slip wheel detection unit. The vehicle height adjusting device according to claim 1, wherein the vehicle height of a portion corresponding to the vehicle height is adjusted. The vehicle height adjusting device according to claim 1, wherein the slip wheel detecting means includes first slip wheel estimating means for detecting a slip wheel based on wheel acceleration. The slip wheel detecting means further comprises second slip wheel estimating means for detecting a slip wheel based on the inclination of the vehicle,
The slip wheel estimated by said 1st slip wheel estimation means and said 2nd slip wheel estimation means, respectively when the slip wheel estimated respectively is the same, it determines with the said estimated slip wheel being said slip wheel. The vehicle height adjusting device described. The vehicle is a two-wheel drive system,
5. The vehicle height adjustment according to claim 3, wherein the first slip wheel detection unit detects the slip wheel by comparing a wheel acceleration of each wheel of the driving wheel and a wheel acceleration of the driven wheel. apparatus. A slip cancellation determination means for determining whether or not the vehicle is in a normal running state in which the slip state is canceled;
The vehicle height adjusting device according to any one of claims 1 to 5, wherein the vehicle height adjusting means continues the adjustment of the vehicle height until the slip elimination means determines that the vehicle is in a normal running state.

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