JP3910766B2 - Vehicle height adjustment device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is used in an automobile equipped with an air suspension that supports a vehicle body by air pressure. The present invention relates to a vehicle height adjustment device capable of adjusting the height of a vehicle body by adjusting the air pressure of an air suspension by operation when loading / unloading luggage or when passengers get on / off.
[0002]
[Prior art]
Cars for carrying luggage using air suspensions are widely used. By using an air suspension for a vehicle for carrying goods, compared to a leaf suspension vehicle using leaf springs, the goods can be run with peace of mind and the service quality for customers can be improved. For this reason, vehicles for carrying goods using air suspensions tend to become more popular.
[0003]
The structure of the air suspension is shown in FIG. As shown in FIG. 4, a plurality of air springs 4 support the frame 1, and the vehicle height can be adjusted by adjusting the pressure inside these air springs 4. Further, by giving a difference between the internal pressures of the air spring 4 provided on the front shaft and the air spring 4 provided on the rear shaft, the vehicle body is inclined or the inclination generated by the load bias is corrected. You can also
[0004]
The state of loading and unloading work is shown in FIG. As shown in FIG. 5, the loading / unloading operation of the load on the vehicle is performed by placing a transfer plate between the loading platform and the platform and reciprocating the forklift between the platform and the loading platform.
[0005]
[Problems to be solved by the invention]
In the load carrying vehicle, as shown in FIG. 5, it is necessary to match the heights of the loading platform and the platform when carrying out the loading and unloading work of the load. At this time, if the pressures inside the plurality of air springs are manually adjusted and the heights are adjusted, for example, the operation of raising the front part and then raising the rear part will be repeated alternately. It takes time to reach high. Also, at this time, the vehicle body shakes like a seesaw, but depending on the load, it may move due to such a shake, and the vehicle height that can reach the target vehicle height as it is while maintaining the inclination of the vehicle. Development of adjustment technology is desired.
[0006]
Japanese Patent Laid-Open No. 10-278533 discloses a technique for adjusting the vehicle height while maintaining the level of the vehicle body. This technique is intended for a bus on which passengers are placed, In the case of commercial vehicles, it is not necessary to stick to maintaining the level as in the case of the related art, and it may remain slightly inclined, so that it is desirable that the vehicle height reach the target value with little shaking. It is.
[0007]
The present invention has been made in such a background, and an object of the present invention is to provide a vehicle height adjusting device that can quickly bring the vehicle height close to the target value. It is an object of the present invention to provide a vehicle height adjustment device that causes less vehicle body shaking associated with vehicle height adjustment.
[0008]
[Means for Solving the Problems]
The present invention is characterized in that a slight inclination of the vehicle body is allowed and the vehicle height is quickly reached the target value. For example, the front vehicle height represented by the distance between the front axle and the vehicle body and the rear vehicle height represented by the distance between the rear axle and the vehicle body are measured, and the difference between the heights is calculated. Furthermore, a change in the height difference at different times is detected. At this time, if a difference occurs in the difference in height at different times, the inclination of the vehicle body has changed. Appropriate control is applied if the change in inclination deviates from the allowable range. However, if the change in the inclination is within the allowable range, the vehicle height is brought close to the target value as it is. Accordingly, the vehicle height can be quickly adjusted to a desired height without performing redundant control for keeping the cargo bed floor surface horizontal.
[0009]
It is also possible to store a predetermined height in advance and automatically bring the vehicle height close to that height. Since the loading and unloading work is performed from the rear of the vehicle, the rear vehicle height is brought close to the target value. At this time, the adjustment of the front vehicle height is performed by calculating the difference in height and appropriately controlling if the change in the height difference at different times deviates from the allowable range.
[0010]
In this way, the vehicle height can be quickly brought close to the target value. At this time, since the vehicle body does not stick to the horizontal maintenance, the vehicle body shake associated with the vehicle height adjustment can be reduced.
[0011]
That is, the present invention is a vehicle height adjustment device that is installed in a vehicle having air suspensions on the front wheels and rear wheels, respectively, and adjusts the distance between the axle and the vehicle body by adjusting the pressure of the air suspension.
[0012]
Here, a feature of the present invention is that a sensor for measuring a front vehicle height (hf) represented by a distance between the front axle and the vehicle body, and a rear vehicle height represented by a distance between the rear axle and the vehicle body ( hr), an adjustment valve that mainly adjusts the front vehicle height (hf), an adjustment valve that mainly adjusts the rear vehicle height, one vehicle height adjustment operation end, and this vehicle height adjustment operation end. And a control circuit for controlling the opening and closing of the two regulating valves, respectively, when the operation input for changing the vehicle height is received. Vehicle height difference from sensor output Δ = hr−hf
And a control means for opening and closing the two regulating valves so that the vehicle height difference Δ is maintained substantially constant.
[0013]
Further, means for storing the desired rear vehicle height H in advance is provided, and when the control circuit receives an operation input for changing the vehicle height, the actual rear vehicle height hr is stored in the storage means. A control unit that opens and closes the two regulating valves so that the vehicle height difference Δ is maintained substantially constant until the vehicle height H is reached may also be included.
[0014]
Thus, when the desired vehicle height is known in advance, the vehicle height can be stored in the memory in advance, and the vehicle height can be automatically adjusted.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
The configuration of the vehicle height adjusting device according to the embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of a main part of a vehicle height adjusting device according to an embodiment of the present invention.
[0016]
The present invention is a vehicle height adjusting device that is installed in a vehicle having air suspensions on front wheels and rear wheels, and adjusts the distance between the axle and the vehicle body by adjusting the pressure of the air suspension.
[0017]
Here, as shown in FIG. 1, a feature of the present invention is that a height sensor 5f that measures a front vehicle height (hf) represented by a distance between the front axle and the vehicle body, and a rear axle and the vehicle body Height sensor 5r for measuring rear vehicle height (hr) represented by distance, magnetic valve 7f as an adjustment valve for mainly adjusting front vehicle height (hf), and adjustment valve for mainly adjusting rear vehicle height And a remote control switch 11 as one vehicle height adjustment operation end, and an operation amount of the remote control switch 11 and outputs of the height sensors 5f and 5r are input to control the opening and closing of the magnetic valves 7f and 7r, respectively. And a control unit 10 as a control circuit. When there is an operation input for changing the vehicle height, the control unit 10 has height sensors 5f and 5r. Vehicle height difference from the output Δ = hr-hf
Is calculated and the magnetic valves 7f and 7r are opened and closed so that the vehicle height difference Δ is maintained substantially constant.
[0018]
Further, in order to automatically adjust the vehicle height, the remote control switch 11 is provided with a memory (not shown) as means for storing the desired rear vehicle height H in advance, and the control unit 10 changes the vehicle height. When the operation input is made, the magnetic valves 7f and 7r are opened and closed so that the vehicle height difference Δ is maintained substantially constant until the actual rear vehicle height hr reaches the rear vehicle height H stored in the memory. It can also be set as the structure to do.
[0019]
As shown in FIG. 1, there are four height sensors 5r, two for each of the R1 axis and the R2 axis. When the output values of the height sensors 5r are hr11, hr12, hr21, and hr22, respectively. The rear vehicle height hr is
hr = (hr11 + hr12) / 2
Or
hr = (hr21 + hr22) / 2
Or
hr = (hr11 + hr12 + hr21 + hr22) / 4
Determine as
[0020]
Next, the operation of the vehicle height adjusting device according to the embodiment of the present invention will be described with reference to FIGS. FIG. 2 is a flowchart showing a manual vehicle height adjustment procedure. FIG. 3 is a flowchart showing an automatic vehicle height adjustment procedure.
[0021]
As shown in FIG. 2, when the driver turns on the simultaneous up / down switch of the remote control switch 11 (S0), the control unit 10 receives this and measures the rear vehicle height hr0 and the front vehicle height hf0 at time t0. (S1). The vehicle height is measured by the height sensor 5. As shown in FIG. 4, the height sensor 5 measures the height of the frame 1 with the support beam 3 as a reference position. further,
hr0−hf0 = Δ0
Is calculated (S2). Subsequently, the front and rear air springs 4 are respectively pressurized to raise and lower the front and rear simultaneously (S3). Next, at time t1, the rear vehicle height hr1 and the front vehicle height hf1 are measured again (S4). further,
hr1-hf1 = Δ1
Is calculated (S5). continue,
δ = Δ1-Δ0
Is calculated (S6). Here, the threshold values a and δ are compared. If δ is larger than the threshold value a (S7), it means that the rear part of the vehicle has risen more than the front part from time t0 to time t1, so the rear part is temporarily stopped to Only the part is raised (S10). In addition, when δ is smaller than the threshold −a (S8), it means that the front part of the vehicle has risen more than the rear part from time t0 to time t1, so once the front part The ascent is stopped and only the rear part is raised (S11). When δ is smaller than the threshold value a and larger than the threshold value −a, the front and rear of the vehicle are simultaneously raised (S9).
[0022]
The value of a is determined by the allowable inclination angle of the vehicle. When the allowable range of the tilt angle is wide, the value of a can be set to a large value, and when the allowable range of the tilt angle is narrow, the value of a is set to a small value. If a = 0, the vehicle moves up while keeping the level. In the embodiment of the present invention, a = 5 mm. The time interval between time t0 and time t1 was 0.1 second.
[0023]
In this way, when the vehicle height rises and the driver recognizes that the vehicle height has reached the desired vehicle height and turns off the lift switch of the remote control switch 11 (S12), the vehicle height adjustment ends.
[0024]
In addition, as shown in FIG. 3, a desired vehicle height H can be set in advance and the vehicle height H can be automatically adjusted. Since the present invention is applied to a load carrying vehicle, the vehicle height H is the vehicle height at the rear of the vehicle where the loading and unloading operations are performed, and the vehicle height at the front of the vehicle is not particularly set. Adjustment is performed so as to follow the adjustment.
[0025]
As shown in FIG. 3, when the driver turns on the memory switch M of the remote control switch 11 (S20), the control unit 10 receives this and reads the set value H stored in the memory in the remote control switch 11 in advance. (S21). Subsequently, the rear vehicle height hr0 and the front vehicle height hf0 at time t0 are measured (S1). further,
hr0−hf0 = Δ0
Is calculated (S2). Subsequently, the front and rear air springs 4 are respectively pressurized to raise and lower the front and rear simultaneously (S3). Next, at time t1, the rear vehicle height hr1 and the front vehicle height hf1 are measured again (S4). further,
hr1-hf1 = Δ1
Is calculated (S5). continue,
δ = Δ1-Δ0
Is calculated (S6). Here, the threshold values a and δ are compared. The threshold value a is 5 mm, for example. If δ is larger than the threshold value a (S7), it means that the rear part of the vehicle has risen more than the front part from time t0 to time t1, so the rear part is temporarily stopped to Only the part is raised (S10). In addition, when δ is smaller than the threshold −a (S8), it means that the front part of the vehicle has risen more than the rear part from time t0 to time t1, so once the front part The ascent is stopped and only the rear part is raised (S11). When δ is smaller than the threshold value a and larger than the threshold value −a, the front and rear of the vehicle are simultaneously raised (S9).
[0026]
Thus, the vehicle height rises, and the control unit 10 recognizes that the vehicle height at the rear of the vehicle eventually becomes the preset vehicle height H (S22), and ends the adjustment of the vehicle height.
[0027]
In this way, the vehicle height is adjusted, and as shown in FIG. 5, the loading / unloading work is performed by adjusting the height of the loading platform floor relative to the platform to the optimum height. After the loading and unloading work is completed, it is necessary to adjust the vehicle height to the optimum vehicle height when traveling, and the vehicle height at this time is also set in advance in the memory of the remote control switch 11 as a desired vehicle height, It can also be adjusted automatically [Effect of the invention]
As described above, according to the present invention, the vehicle height can be quickly brought close to the target value. At this time, the shaking of the vehicle body accompanying the vehicle height adjustment can be reduced.
[Brief description of the drawings]
FIG. 1 is a block diagram of a main part of a vehicle height adjusting device according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a procedure for manually adjusting the vehicle height.
FIG. 3 is a flowchart showing a procedure for automatically adjusting the vehicle height.
FIG. 4 is a diagram showing a configuration of an air suspension.
FIG. 5 is a diagram showing a state of loading and unloading work.
[Explanation of symbols]
1 Frame 2 Axle 3 Support beam 4 Air spring 5f, 5r Height sensor 6 Shock absorber 7f, 7r Magnetic valve 10 Control unit 11 Remote control switch

Claims (2)

In a vehicle height adjustment device that is mounted on a vehicle having an air suspension on each of the front wheel and the rear wheel and adjusts the distance between the axle and the vehicle body by adjusting the pressure of the air suspension,
A sensor for measuring the front vehicle height (hf) represented by the distance between the front axle and the vehicle body, a sensor for measuring the rear vehicle height (hr) represented by the distance between the rear axle and the vehicle body, and mainly the front vehicle An adjustment valve that adjusts the height (hf), an adjustment valve that mainly adjusts the rear vehicle height, one vehicle height adjustment operation end, an operation amount of the vehicle height adjustment operation end, and the two sensor outputs are input. A control circuit for controlling the opening and closing of the two regulating valves,
When there is an operation input for changing the vehicle height, the control circuit calculates the vehicle height difference Δ = hr−hf from the two sensor outputs.
Means for computing
Change in vehicle height difference between this vehicle height difference and time t0 to time t1
δ = Δt1−Δt0
Means for computing
And a control means for opening and closing the two adjusting valves so that the detected change in vehicle height difference δ maintains a predetermined threshold range . Means for storing the desired rear vehicle height H in advance is provided, and when the control circuit receives an operation input for changing the vehicle height, the actual rear vehicle height hr is stored in the storage means. The vehicle height adjusting device according to claim 1, further comprising a control means for opening and closing the two adjusting valves so that the change δ of the vehicle height difference maintains a predetermined threshold range until reaching H.

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