JP6750267B2 - Vehicle height adjustment device - Google Patents

Description

The present invention relates to a vehicle height adjusting device.

Patent Document 1 discloses a vehicle suspension device that adjusts a ground load according to the state of each wheel. In the vehicle suspension device of Patent Document 1, a plurality of wheels are provided with absorbers that can change the ground load using a motor. When at least one of the plurality of wheels slips, the motor is driven so as to increase the ground load of the wheels other than the wheel in which the slip has occurred. The motor is driven for a predetermined time to disperse the ground load of the slipped wheel to the other wheels.

Patent Document 2 discloses a vehicle control device that appropriately transmits the driving force of the vehicle to a road surface. In the vehicle control device of Patent Document 2, an ungrounded wheel detection unit that detects an ungrounded wheel that is a wheel that is not properly grounded on the road surface, and an upward or downward inertial force is applied to a vehicle portion around the wheel. The inertial force means to generate is provided. When a non-grounding wheel not installed on the road surface is detected and two non-grounding wheels located diagonally are detected, a downward inertial force is generated on one of the non-grounding wheels at substantially the same timing. Then, an inertial force in the upward direction is generated on the other non-grounded wheel, whereby 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 contact load is transferred to the remaining right side of the front wheel and the left and right wheels of the rear wheel. Since the differential distributes the torque to the wheels with low resistance, the driving force is slipped to the left side of the idle front wheel. Therefore, since the driving force of the front wheels is lost and the driving force is substantially the driving force of the two rear wheels, the driving force decreases, and it may take time to avoid the stack or it may not be possible to avoid the stack.

In Patent Document 2, in order to swing the vehicle, it is a precondition that there are two diagonal ground wheels. In addition, energy is consumed to swing the vehicle, and the stack cannot be efficiently avoided.

The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a vehicle height adjusting device that can efficiently avoid a stack.

A vehicle height adjusting 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 slip has occurred, and the relative position of each wheel and the vehicle main body by changing the relative position of the vehicle main body. A vehicle height adjusting means for adjusting the vehicle height of the vehicle height adjusting means, the vehicle height adjusting means, when the slip wheel is detected by the slip wheel detecting means, such that the ground load of the slip wheel becomes large, The vehicle height of a portion corresponding to the position of the wheel other than the slip wheel is adjusted.

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

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

According to such a configuration, the air suspension system adjusts the vehicle height of the vehicle body by changing the relative positions of the wheels and the vehicle body by supplying and discharging the air in the air spring. Compared with metal springs, the spring characteristics can be selected relatively freely. Therefore, the air suspension system has a low spring constant and is in a soft state as compared with a suspension system using a metal spring. Therefore, when a vehicle using the air suspension system travels, for example, on an uphill road, the rear wheels easily sink and the front wheels float, so that the front wheels easily slip. Therefore, when the vehicle is traveling on a slope and the slip wheel detecting means detects the slip wheel, the vehicle height adjusting means adjusts the position of the wheel other than the slip wheel so that the ground load of the slip wheel increases. Adjust the vehicle height of the corresponding part. As a result, the reduction of the driving force of the vehicle due to the slip is avoided, and the driving force of the slip wheels can be increased. Therefore, even when the vehicle using the air suspension system is traveling on a slope, the driving force of the wheels can be appropriately transmitted to the road surface, so that the stack 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.

With such a configuration, when 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.

With such a configuration, when a slip occurs on any of the wheels, the slip wheel is estimated by double estimation by the first slip wheel estimation means and 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 wheels with the wheel acceleration of the driven wheel. May be

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

The vehicle height adjusting device further comprises a slip cancellation determining means for determining whether or not the vehicle is in a normal traveling state in which the slip state is eliminated, and the vehicle height adjusting means is in a normal traveling state by the slip eliminating means. The adjustment of the vehicle height may be continued until the determination is made.

With 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 wheels can be increased surely and quickly.

According to the present invention, it is possible to provide a vehicle height adjusting device that can efficiently avoid a stack.

The block diagram of the vehicle height adjusting device which concerns on one Embodiment of this invention. The flowchart figure which shows the operation 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 at the time of raising vehicle height, without operating the compressor which concerns on this invention. The block diagram of the air suspension system at the time of operating the compressor which concerns on this invention, and raising vehicle height. The block diagram of the air suspension system in case the vehicle height is made low according to the present invention.

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

FIG. 1 shows the 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 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 detecting means 22 includes a first slip wheel estimating means 23 and a second slip wheel estimating means 24.

The vehicle height sensor 10 is provided for each wheel, detects the movement of the suspension, and detects the vehicle height of the vehicle. The wheel speed sensor 11 is provided for each wheel and detects the wheel speed based on the rotation speed of each wheel. The longitudinal/lateral acceleration sensor 12 is provided in the vehicle and detects the 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 result of each sensor is output to the ECU 14.

The tilt detecting means 20 detects the tilt of the vehicle from the detection results of the front/rear/lateral acceleration sensor 12. The slope determining means 21 determines whether the vehicle is traveling on a slope based on the inclination of the vehicle detected by the inclination detecting means 20.

The vehicle includes an air suspension system 13. Since the air suspension system 13 adjusts the vehicle height by supplying and exhausting 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 has a low spring constant and is in a soft state as compared with a suspension system using a metal spring. For this reason, when a vehicle equipped with the air suspension system 13 travels on an uphill slope, the rear wheels are likely to sink and the front wheels float, so that the front wheels easily slip. Further, when traveling on a downhill slope, the front wheels easily sink and the rear wheels float, so that the rear wheels easily slip. Therefore, in the present embodiment, an example will be described in which the slope determination means 21 determines that the vehicle is traveling on a slope. First, when the slope detecting means determines that the vehicle is traveling on a slope, the operation procedure shown in FIG. 2 is performed. FIG. 2 is a flowchart showing the operation procedure according to the present invention.

First, the ECU 14 time-differentiates the wheel speed obtained from the wheel speed sensor 11 to calculate the acceleration of each wheel (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 drive wheels with the acceleration of the driven wheel (S12). Since the acceleration of the driven wheel is substantially equal to the acceleration of the vehicle body, when 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, when the value of (wheel acceleration of driving wheel−wheel acceleration of driven wheel) for each drive wheel exceeds the slip determination threshold value, the first slip estimating means 23 determines that slip has occurred and determines the slip determination threshold value. The drive wheels that exceed the above are estimated as slip wheels. When the slip wheels are not detected by the first slip estimating means 23, the ECU 14 determines that the slip has not occurred, and ends the processing in this flowchart.

Next, the inclination detection means 20 detects the inclination of the vehicle from the detection result of the front/rear/lateral acceleration sensor 12 (S13). Then, the second slip estimating means 24 of the slip wheel detecting means 22 estimates the slip wheel based on the inclination of the vehicle (S14). When the vehicle leans, some wheels are not in proper contact with the road surface. Therefore, the slip wheel can be estimated based on the inclination of the vehicle.

The slip wheel detecting means 22 determines the slip wheel based on the slip wheels estimated by the first slip wheel estimating means 23 and the second slip wheel estimating means 24, respectively (S15). If the estimated slip wheels are the same, the slip wheel detection means 22 determines that the wheel is a slip wheel. When a slip occurs on any of the wheels, the slip wheel is reliably detected by estimating the slip wheel by double estimation by the first slip wheel estimating means 22 and the second slip wheel estimating means 23. be able to. When the slip wheel detecting unit 22 does not detect the slip wheel, the ECU 14 determines that the slip has not occurred, and ends the processing in this flowchart.

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. When the slip wheel is detected by the slip wheel detecting means 22, the vehicle height adjusting means 25 adjusts the vehicle height of a portion corresponding to the position of the wheel other than the slip wheel so that the ground load of the slip wheel becomes large (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 & motor 34, a dryer 35, a filter 36, and a tube 37. The 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 to increase the vehicle height in the air spring 30 if the vehicle height becomes higher than the target vehicle height. The vehicle height is adjusted by exhausting air from the vehicle and lowering the vehicle height. The air suspension system 13 raises or lowers the vehicle height of a portion corresponding to the position of a wheel other than the slip wheel so that the ground load of the slip wheel becomes large. For example, when the left side of the front wheel slips, the vehicle heights of the parts corresponding to the positions of the right side of the front wheel and the left and right wheels of the rear wheel are adjusted.

The vehicle height control of the air suspension system 13 will be schematically described below with reference to FIGS. 4 to 6. The control for increasing the vehicle height of the air suspension system 13 may operate the compressor & motor 34 as shown in Figs. 4 and 6, or may not operate the compressor & motor 34 as shown in Fig. 5.

When operating the compressor & motor 34 shown in FIG. 4, the valves 31c and 31e are opened. The compressor & motor 34 sucks the air from the tank 32 and discharges it to the air spring 30 side to increase the vehicle height. When the compressor & motor 34 shown in FIG. 5 is not operated, the valves 31c, 31d, 31e, 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 lowering the vehicle height of the air suspension system 13 shown in FIG. 6 opens the valves 31d and 31f. The compressor & motor 34 sucks the air from the air spring 30 side and discharges the air to the tank 32, thereby lowering 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 a portion corresponding to the position of the wheel other than the slip wheel so that the ground load of the slip wheel becomes large. As a result, the reduction of the driving force of the vehicle due to the slip is avoided, and the driving force of the slip wheels can be increased. Therefore, the driving force of the wheels can be appropriately transmitted to the road surface. Therefore, the stack can be efficiently avoided.

The slip elimination determination means 26 determines whether or not the vehicle is in the normal traveling state in which the slip state of the vehicle is eliminated based on the comparison result of 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 load of the slip wheel becomes large. Therefore, the driving force of the slip wheels can be increased surely and quickly. When the slip elimination determination means 26 determines that the vehicle is in the normal traveling state in which the slip state is eliminated, the ECU 14 determines that the slip has not occurred and ends the processing in this flowchart.

As described in detail above, according to this embodiment, the following effects are obtained.
(1) According to the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, when a slip occurs on any of the wheels, the slip wheel detecting means 22 detects the slip wheel and the vehicle height adjusting means 25 Adjusts the vehicle height of a portion corresponding to the position of a wheel other than the slip wheel so that the ground load of the slip wheel becomes large. As a result, the slip wheel can be properly grounded on the road surface. Therefore, the reduction of the driving force of the vehicle due to the slip is avoided, and the driving force of the slip wheels can be increased. Therefore, the driving force of the wheels can be appropriately transmitted to the road surface. Therefore, the stack can be efficiently avoided.
(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 the wheels and the vehicle body are relatively moved. 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 has a low spring constant and is in a soft state as compared with a suspension system using a metal spring. For this reason, when a vehicle using the air suspension system 13 travels, for example, on an uphill slope, the rear wheels easily sink and the front wheels float, so the front wheels easily slip. Therefore, when the slope determining means 21 is traveling on a slope and the slip wheel detecting means 22 detects a slip wheel, the vehicle height adjusting means 25 causes wheels other than the slip wheels to increase the ground load of the slip wheels. Adjust the vehicle height of the part corresponding to the position. As a result, the reduction of the driving force of the vehicle due to the slip is avoided, and the driving force of the slip wheels can be increased. Therefore, since the driving force of the wheels can be appropriately transmitted to the road surface even when the vehicle using the air suspension system 13 is traveling on a slope, the stack can be efficiently avoided.
(3) With the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, when slip occurs on any of the wheels, the slip wheel can be easily detected by detecting the slip wheel based on the wheel acceleration. Can be detected.
(4) With the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, when slip occurs on any of the wheels, the estimation by the first slip wheel estimating means 23 and the second slip wheel estimating means 24. The slip wheel can be reliably detected by estimating the slip wheel by double estimation.
(5) With 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 on the drive wheels that generate the driving force becomes a problem. The wheel acceleration of the driven wheel is almost the same as the vehicle body acceleration. Further, when the acceleration of the driving wheels is faster than the acceleration of the vehicle body, it can be said that the driving wheels are slipping. Therefore, the slip wheel can be easily detected by comparing the wheel accelerations of the drive wheels and the driven wheels.
(6) With the configuration of the vehicle height adjusting device according to the above-described embodiment of the present invention, the positions of the wheels other than the slip wheels are adjusted so that the ground load of the slip wheels increases until the slip is eliminated. It is possible to repeat the adjustment of the vehicle height of the portion corresponding to. Therefore, the driving force of the slip wheels can be increased surely and quickly.
(Other embodiments)
In the above-described embodiment, the slip wheel detection means 22 is described as including 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.

Further, 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 leaf spring type and coil spring type may be used.

Further, although the vehicle is of the two-wheel drive type in the above-described embodiment, the present invention can be applied to the four-wheel drive type. 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 a portion corresponding to the position of the wheel other than the slip wheel is adjusted so that the ground load of the slip wheel is increased. Good.

Further, in the above-described embodiment, the ECU 14 is provided with the slope determining means 21, and if the slope determining means 21 determines that the vehicle is traveling on a slope, the operation procedure shown in FIG. 2 is described. The invention is not limited to this. The ECU 14 may be a vehicle control device that does not include the slope detecting means 21 and performs the operation procedure shown in FIG.

10: Vehicle height sensor 11: Wheel speed sensor 12: Front/rear/lateral acceleration sensor 13: Air suspension system 14: ECU
20: Inclination detecting means 21: Slope judging means 22: Slip wheel detecting means 23: First slip wheel estimating means 24: Second slip wheel estimating means 25: Vehicle height adjusting means 26: Slip elimination judging 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 that is a wheel in which slip has occurred,
A vehicle height adjusting means for adjusting the vehicle height of the vehicle body by changing the relative position of each wheel and the vehicle body,
The vehicle height adjusting means, when the slip wheel is detected by the slip wheel detecting means, the vehicle height of a portion corresponding to the position of the wheel other than the slip wheel such that the ground load of the slip wheel becomes large. adjust,
The vehicle further comprises slope determining means for determining whether the vehicle is traveling on a slope,
The vehicle height adjusting means adjusts the vehicle height using an air suspension system,
If the vehicle is traveling on a slope by the slope determination means and the slip wheel is detected by the slip wheel detection means, the position of the wheel other than the slip wheel is increased so that the ground load of the slip wheel is increased. Adjust the vehicle height of the part corresponding to
A vehicle height adjusting device characterized in that Slip wheel detecting means for detecting a slip wheel that is a wheel in which slip has occurred,
A vehicle height adjusting means for adjusting the vehicle height of the vehicle body by changing the relative position of each wheel and the vehicle body,
The vehicle height adjusting means, when the slip wheel is detected by the slip wheel detecting means, the vehicle height of a portion corresponding to the position of the wheel other than the slip wheel such that the ground load of the slip wheel becomes large. Adjust
The slip wheel detection means comprises a first slip wheel estimation means for detecting a slip wheel based on wheel acceleration,
The slip wheel detection means further comprises second slip wheel estimation means for detecting a slip wheel based on the inclination of the vehicle,
When the slip wheels estimated by the first slip wheel estimation means and the second slip wheel estimation means are the same, the estimated slip wheel is determined to be the slip wheel. Vehicle height adjustment device. The vehicle height adjusting device according to claim 1 , wherein the slip wheel detection means includes a first slip wheel estimation means that detects a slip wheel based on wheel acceleration. The slip wheel detection means further comprises second slip wheel estimation means for detecting a slip wheel based on the inclination of the vehicle,
If the slip wheels estimated by the first slip wheel estimating means and the second slip wheel estimating means are the same, the estimated slip wheel is determined to be the slip wheel. The vehicle height adjustment device described. The vehicle is a two-wheel drive system,
The vehicle height adjustment according to claim 2, wherein the first slip wheel detection means detects the slip wheel by comparing the wheel acceleration of each wheel of the drive wheels with the wheel acceleration of the driven wheels. apparatus. Further comprising a slip cancellation determination means for determining whether or not the vehicle is in a normal traveling state in which the slip state has been resolved,
6. The vehicle height adjusting device according to claim 1, wherein the vehicle height adjusting means continues adjusting the vehicle height until the slip canceling means determines that the vehicle is in a normal traveling state.

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