JP3480723B2 - Height lock device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle height lock device applied to a transportation vehicle equipped with an air suspension.

[0002]

2. Description of the Related Art FIG. 7 shows an example of a rear suspension structure in a general transportation vehicle such as a truck. Below a pair of left and right frames 1 extending in the longitudinal direction of the vehicle body,
An axle 3 is arranged to extend in the vehicle width direction and to support the wheel 2 at both ends thereof. The front and rear end portions of a support beam 4 integrally assembled to the lower surface of the axle 3 near the end portion and the aforesaid An air bellows 5 that absorbs vertical vibrations is interposed between the lower surface of the frame 1 and the lower surface of the frame 1.

Further, a bracket 6 extending downward is attached to a frame 1 further forward of the air bellows 5 arranged on the front side, and a lower end portion of the bracket 6 and an intermediate portion of the support beam 4 are provided. The spaces are connected so as to be tiltable by a stabilizer 7 that enhances the roll rigidity of the vehicle body.

In FIG. 7, reference numeral 8 denotes a shock absorber that connects the midway portion of the support beam 4 and the frame 1 immediately above to suppress the swinging back and forth of vertical vibration.

Then, as shown in FIG. 8, in a transport vehicle 9 equipped with such an air suspension, when the rear portion of the vehicle is faced to the platform 10 and the loading and unloading work of the luggage on the loading platform 11 is performed, The working air is supplied to and discharged from the bellows 5 to adjust the vehicle height, and the rear end of the luggage carrier 11 and the platform 10 are adjusted in height.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
When loading and unloading luggage from the platform 10 side for 1, the forklift 12 unloads a large amount of luggage at a time, or when the forklift 12 is loaded into and unloaded from the loading platform 11 to load and unload suddenly. There is a problem that the loading platform 11 rises and falls due to the increase and decrease of the vehicle height, and the vehicle height fluctuates greatly. Moreover, in order to keep the vehicle height constant by adjusting the pressure of each air bellows 5 against such vehicle height variation. However, since there is a waiting time until the original vehicle height is restored each time the height of the loading platform 11 changes, there is a problem in that it is difficult to carry out the cargo handling work and the work efficiency is reduced. there were.

If the working air is supplied to and discharged from each air bellows 5 every time the height of the loading platform 11 changes during the cargo handling work, the working air consumption during the work becomes large. There was also the problem that a large capacity air tank had to be installed.

The present invention has been made in view of the above situation, and provides a vehicle height lock device capable of maintaining the vehicle height at a constant height even when the load suddenly increases or decreases during the cargo handling work. Is intended.

[0009]

SUMMARY OF THE INVENTION The present invention is a vehicle height lock device for preventing a vehicle height variation during a cargo handling operation in a transportation vehicle equipped with an air suspension, which is vertically stretchable between a frame and an axle. The jack device so configured as to be capable of being mounted on either one of the frame and the axle, the jack device is extended at the time of loading and unloading, and the other end of the frame and the axle is brought into press contact with the working air from the air bellows of the air suspension. It is characterized in that it is provided with a control device for controlling so that the load of the vehicle body can be extracted and transferred to the jack device.

[0010] Thus, in this way, when the rear part of the vehicle faces the platform to carry out the cargo handling work, the air bellows are actuated so that the height of the rear end of the bed coincides with the height of the platform. After adjusting the vehicle height by supplying and exhausting air, extend the jack device from either the frame or axle to press the tip against the other, and then extract the working air from the air bellows to reduce the vehicle body load. When the vehicle is transferred from the vehicle to the jack device, the vehicle height is fixed by the jack device, and the vehicle height does not fluctuate even if the load suddenly increases or decreases during the cargo handling work.

Further, in the present invention, the control device stores the current vehicle height fixed by the jack device at the end of the cargo handling work, and the air bellows is set to a vehicle height slightly higher than the stored vehicle height. It is preferable that the jack device is contracted after the working air is supplied to return the load of the vehicle body to the air suspension.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show an example of an embodiment for carrying out the present invention, and the portions denoted by the same reference numerals as those in FIG. 7 represent the same things.

As shown in FIG. 1, in the vehicle height lock device according to the present embodiment, the jack device 13 is configured to be vertically expandable and contractable on the outer surfaces of the left and right frames 1 which are located directly above the rear axle 3. Is mounted, and the jack shaft 15 can be projected and retracted downward from the lower end portion of the main body portion 14 which is substantially attached to the outer surface of the frame 1 by bolt fastening or the like.

FIG. 2 shows a detailed internal structure of the jack device 13 in a top view with the casing 16 cut away, and FIG. 3 shows a detailed internal structure of the jack device 13 broken away in the casing 16. However, in the example shown in FIGS. 2 and 3, the screw screw 15a is provided on the lower side portion of the jack shaft 15.
Is formed on the upper part of the spline 1 in the axial direction.
5b is formed.

The screw 15a is screwed with a nut member 17 fixed to the bottom of the casing 16, and the spline 15b is directly above the nut member 17 and is rotatably held around the axis of the jack shaft 15. The rotary shaft 18 meshes with the inner peripheral surface of the rotary shaft 18 so as to rotate together and be guided in the vertical direction.

Further, a worm wheel 19 is externally fitted and mounted at an appropriate position in the vertical direction of the rotary shaft 18, and the worm gear 2 that meshes with the worm wheel 19 is fitted.
0 is integrally supported by a worm shaft 21 horizontally and rotatably installed in the casing 16.

A gear 22 externally fitted and attached to one end of the worm shaft 21 is meshed with a gear 24 of an output shaft of a motor 23 which is fixedly arranged in an upper portion of the casing 16 via a fitting (not shown). The worm shaft 21 is rotated by the normal rotation and the reverse rotation of the motor 23 to rotate the jack shaft 15 together with the rotary shaft 18 via the worm gear 20 and the worm wheel 19, and the jack shaft 15 is connected to the screw screw 15a and the nut member 17. The screwing is used to move up and down in the rotary shaft 18.

Incidentally, 25 in FIG. 3 is a jack shaft 15.
Shows a limit switch for detecting that the is fully retracted.

As shown in FIG. 4, the jack device 13 thus constructed has a control valve 27, which is installed between each air bellows 5 and the air tank 26.
Control device 2 for controlling vehicle height by controlling 28
Although the operation is controlled by 9, the command itself for starting the operation is manually performed by the driver by the vehicle height fixing switch 30 provided in the driver's cab.

An operation command from the control device 29 to the jack device 13 is output as an electric signal via the motor load detection circuit 31, and the motor load detection circuit 31 outputs a jack. Motor 23 of device 13
The current value consumed by is detected and input to the control device 29.

Signals from a vehicle height adjusting switch 32, a vehicle height memory switch 33, and a vehicle height raising / lowering switch 34, which are installed in the driver's seat, are also input to the control device 29.

Here, the vehicle height adjustment switch 32 is for switching the vehicle height control in the control device 29 to either the traveling mode or the cargo handling mode, and the vehicle height memory switch 33 is for a plurality of vehicle heights ( (Corresponding to the platform height for each cargo work place) is divided into a plurality of switch positions so that the control device 29 can be selectively instructed.
In the above, the control device 29 can be instructed to raise or lower the vehicle height to a desired height as required.

Further, the control device 29 is provided with a detection signal from a vehicle height sensor 35 on the rear side, which is necessary for performing vehicle height control,
A detection signal from a pressure sensor 36 that detects the pressure of each air bellows 5 is also input.

Then, in the control device 29, when carrying out the cargo handling work with the rear part of the vehicle facing the platform 10 (see FIG. 8), the cargo handling mode is selected by the vehicle height adjustment switch 32, and the height of the platform is already adjusted. When the vehicle height memory switch 33 selects the platform height of the loading / unloading work place when the vehicle height is stored in memory, when the current vehicle height is lower than the height of the platform 10, both control valves 27 and 28 are opened. Working air is replenished from the air tank 26 to each air bellows 5,
When the current vehicle height is higher than the height of the platform 10, the control valve 28 is opened, the control valve 27 is closed to the air tank 26 side, and each air bellows 5 side is opened to the atmosphere to open the air bellows 5 side. The working air is extracted from the rear side, and the height of the rear end of the loading platform 11 and the height of the platform 10 are adjusted. If the platform height is not in the memory, the vehicle height up / down switch 34 is used.
The driver adjusts the heights of the rear end and the platform 10 to coincide with each other. After that, when the vehicle height fixing switch 30 is turned on, the jack device 13 is operated by the control procedure shown in the flowchart of FIG.

That is, when it is confirmed in step S1 that the vehicle height fixing switch 30 is turned on, in the next step S2, the jack shaft 15 directed to the jack device 13 is provided.
Is output, which causes the motor 23 of the jack device 13 to rotate in the forward direction to cause the jack shaft 15 to rotate.
Extends downward, and as shown by the chain double-dashed line in FIG. 1, the tip of the jack shaft 15 is in pressure contact with the upper surface of the axle 3.

Then, in the next step S3, it is judged based on the current value of the motor 23 detected by the motor load detection circuit 31 whether or not the extension of the jack shaft 15 has stopped.

That is, the jack shaft 1 is provided on the upper surface of the axle 3.
When the tip end of 5 is pressed, the motor 23 is overloaded because it cannot be further extended downward, and the current value consumed by the motor 23 rises rapidly in a stepwise manner. Detects that the expansion of the has stopped.

The determination result in the previous step S3 is "Y
If "ES", the process proceeds to the next step S4 to instruct to stop the motor 23 of the jack device 13, and if the determination result in step S3 is "NO", the determination in step S3 is made. Is repeated.

Further, after the extension operation of the jack device 13 is stopped, in step S5, each air bellows 5 is
Is instructed to discharge the operating air, the control valves 27 and 28 are operated to start discharging the operating air from each air bellows 5, and the load of the vehicle body is transferred to the jack device 13.

When extracting the working air from each air bellows 5, the pressure sensor 36 monitors the working pressure so that it does not drop below the minimum pressure at which the function of the air bellows 5 can be maintained. Be sure to finish extracting the.

When the load of the vehicle body is transferred to the jack device 13 as described above, the vehicle height fixing switch 30 is turned off, and the control procedure shown in the flow chart of FIG. 6 is adopted. First, in step S6, the vehicle height fixing switch 30 is
Is confirmed to be off, the current rear vehicle height is temporarily stored in the control device 29 based on the detection signal from the vehicle height sensor 35 in the next step S7. It is instructed to replenish the working air to the air bellows 5, which causes the control valves 27, 2
8 is operated to start replenishment of operating air from the air tank 26 to each air bellows 5.

Then, in the next step S9, whether the vehicle height on the rear side detected by the vehicle height sensor 35 becomes the vehicle height + α (vehicle height slightly higher than the memory vehicle height) in the previous step S7. It is determined whether or not the result is “YE
If it is "S", the process proceeds to the next step S10, the supplement of the working air to each air bellows 5 is stopped, the pressure of each air bellows 5 is sealed by the control valve 28, and the determination in step S9 is performed. If the result is "NO", the determination in step S9 is repeated.

Further, after the pressure of each air bellows 5 is sealed, a command for shortening and storing the jack shaft 15 of the jack device 13 is output in step S11, whereby the motor 23 of the jack device 13 is output. Is reversed to shorten the jack shaft 15 in the upward direction, the jack shaft 15 is stored in the main body portion 14, and the load of the vehicle body is returned to each air bellows 5.

Then, in the next step S12,
The limit switch 25 of the jack device 13 determines whether or not the jack shaft 15 is completely stored,
If the determination result is “YES”, the process proceeds to the next step S13 to instruct to stop the motor 23 of the jack device 13, and if the determination result in step S12 is “NO”, The determination in step S12 will be repeated.

Further, after the jack shaft 15 of the jack device 13 is completely retracted, in step S14, the working air is discharged from each air bellows 5 in order to reduce the vehicle height of α added to the memory vehicle height. In response to this command, the control valves 27 and 28 are operated to start discharge of operating air from each air bellows 5, and the vehicle height is controlled to the vehicle height stored in step S7.

When the vehicle height lock device is controlled by the control device 29, the height of the rear end of the loading platform 11 is adjusted so that the rear end of the vehicle faces the platform 10 and the cargo handling work is performed. After adjusting the vehicle height by supplying / discharging the working air to / from each air bellows 5 to match the height of the vehicle, the vehicle height fixing switch 30 is turned on to extend the jack shaft 15 of the jack device 13. When the tip of the jack shaft 15 is pressed against the upper surface of the axle 3, then the working air is extracted from each air bellows 5 and the load of the vehicle body is transferred from each air bellows 5 to the jack device 13. Will fix the vehicle height.

When the loading and unloading work is completed, the vehicle height fixing switch 30 is turned off, and each air bellows 5
After the working air is replenished and the load of the vehicle body is returned from the jack device 13 to each air bellows 5, the jack shaft 15 of the jack device 13 may be shortened and stored.

Therefore, according to the above-described embodiment, the vehicle height can be fixed by the jack device 13, so that the vehicle height can be maintained at a constant height even if the load suddenly increases or decreases during the cargo handling work. Therefore, the cargo handling work can be easily performed, and the work efficiency can be significantly improved.

Further, since there is no change in the vehicle height during the cargo handling work, it is not necessary to supply or discharge the working air to or from each air bellows 5 to control the vehicle height at a constant level. It is possible to reduce the capacity of the air tank 26 by significantly suppressing the above.

The vehicle height lock device according to the present invention is not limited to the above-described embodiment, and the structure of the jack device is not limited to the illustrated example, and the scope of the present invention is not deviated. Of course, various changes can be made within.

[0042]

According to the vehicle height lock device of the present invention described above, various excellent effects as described below can be obtained.

(I) The load of the vehicle body is transferred from the air bellows to the jack device by extending the jack device during the cargo handling work to extract the working air from the air bellows, and the vehicle height is fixed by the jack device. Since the vehicle height can be maintained, the vehicle height can be maintained at a constant height even if the loading load suddenly increases or decreases during the cargo handling work, and the cargo handling work can be performed easily and the work efficiency can be significantly improved. it can.

(II) Since the vehicle height does not fluctuate during the cargo handling work, it is not necessary to supply and discharge the working air to each air bellows to control the vehicle height at a constant level. It is possible to remarkably suppress the above and reduce the capacity of the air tank.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment for carrying out the present invention.

FIG. 2 is a top view showing a detail of the jack device of FIG. 1 with a part thereof cut away.

FIG. 3 is a front view showing a detail of the jack device of FIG. 1 with a part thereof cut away.

FIG. 4 is a block diagram showing a control system in an example of an embodiment of the present invention.

FIG. 5 is a flowchart showing a control procedure when the vehicle height is fixed by the control device of FIG.

6 is a flowchart showing a control procedure at the time of releasing the fixation by the control device of FIG.

FIG. 7 is a side view showing an example of a rear suspension structure in a general transport vehicle.

FIG. 8 is a schematic diagram illustrating a cargo handling operation from a platform for a transport vehicle.

[Explanation of symbols]

1 frame 3 axles 5 Air bellows 9 transport vehicles 13 Jack device 15 jack shaft 23 motor 26 Air tank 27 Control valve 28 Control valve 29 Control device 30 vehicle height fixed switch

Front page continuation (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60G 17/015 B60P 1/02

Claims (2)

(57) [Claims] 1. A vehicle height lock device for preventing a vehicle height variation during a cargo handling operation in a transportation vehicle equipped with an air suspension, the jack device being capable of extending and contracting vertically between a frame and an axle. The jack device is mounted on either one of the frame and the axle, the jack device is extended during loading and unloading work, and the other end of the frame and axle is pressed against the other end, and then the working air is extracted from the air bellows of the air suspension. A vehicle height lock device comprising a control device for controlling transfer to a vehicle. 2. The control device stores the current vehicle height fixed by the jack device at the end of the cargo handling work, and supplies operating air to the air bellows so that the vehicle height becomes slightly higher than the stored vehicle height. The vehicle height lock device according to claim 1, wherein the jack device is contracted after that, and the load of the vehicle body is returned to the air suspension.