JP2002274139A - Height lock device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a height lock device that can hold a height at a constant height even when a live load suddenly increases or decreases in a cargo handling operation. SOLUTION: The height lock device for preventing a height fluctuation in a cargo handling operation in a transportation vehicle equipped with an air suspension mounts a vertically telescopic jack device 13 on a frame 1, and comprises a controller for control capable of extending the jack device 13 in a cargo handling operation until a tip is in pressure contact with an axle 3 and then bleeding an air bellows of the air suspension of working air to thus transfer the load of a vehicle body to the jack device 13.

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 transport 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 transporting vehicle such as a truck, which is provided below a pair of left and right frames 1 extending in the front-rear direction of the vehicle body.
An axle 3 extending in the vehicle width direction and supporting the wheel 2 at both ends thereof is disposed. The front and rear ends of a support beam 4 integrally mounted on a lower surface near the end of the axle 3 are provided. An air bellows 5 for absorbing vertical vibration is interposed between the lower surface of the frame 1 and the lower surface.

[0003] A bracket 6 extending downward is attached to the frame 1 further forward of the air bellows 5 disposed on the front side, and a lower end of the bracket 6 and an intermediate portion of the support beam 4 are connected to each other. The space is connected by a stabilizer 7 that increases the roll rigidity of the vehicle body so as to be tiltable.

[0004] In Fig. 7, reference numeral 8 denotes a shock absorber that connects the middle portion of the support beam 4 and the frame 1 directly above the vehicle to suppress the rebound of vertical vibration.

[0005] As shown in FIG. 8, in the transport vehicle 9 equipped with such an air suspension, when the loading / unloading operation of the cargo on the loading platform 11 is performed with the rear portion of the vehicle facing the platform 10, each air is supplied. The height of the rear end of the bed 11 and the height of the platform 10 are adjusted by supplying and discharging working air to and from the bellows 5 to adjust the vehicle height.

[0006]

However, the carrier 1
When loading or unloading a large amount of luggage from the platform 10 at one time with the forklift 12, or loading and unloading the luggage with the forklift 12 on the loading platform 11, There is a problem that the load 11 rises and lowers greatly due to the increase and decrease in the vehicle height, and the vehicle height fluctuates greatly. In addition, in order to keep the vehicle height constant by adjusting the pressure of each air bellows 5 in response to such a vehicle height fluctuation. However, since the waiting time until returning to the original vehicle height occurs each time the height of the loading platform 11 changes, there is a problem that it is difficult to perform the cargo handling work and the work efficiency is reduced. there were.

[0007] Further, if air is supplied to and discharged from each air bellows 5 every time the height of the carrier 11 fluctuates during the loading operation, the consumption of the operating air during the operation increases. There was also a problem that a large capacity air tank had to be installed.

The present invention has been made in view of the above-mentioned circumstances, and provides a vehicle height locking device capable of maintaining a vehicle height at a constant height even when the load suddenly increases or decreases during a cargo handling operation. It is intended to be.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a vehicle height lock device for preventing a vehicle height from fluctuating during a cargo handling operation in a transport vehicle equipped with an air suspension, and includes a vertically extending and contracting device between a frame and an axle. The jack device is mounted on one of the frame and the axle, and the jack device is extended at the time of loading and unloading to press the tip against the other of the frame and the axle. A control device is provided for performing control so that the load of the vehicle body can be extracted and transferred to the jack device.

[0010] According to this configuration, when the cargo handling operation is performed with the rear portion of the vehicle facing the platform, the air bellows are operated with respect to the air bellows so that the height of the rear end of the platform matches the height of the platform. After adjusting the vehicle height by supplying and discharging air, the jack device is extended from either the frame or the axle to press the tip against the other, and then the working air is extracted from the air bellows to reduce the load on the vehicle body. When the vehicle is transferred to the jack device from above, the vehicle height is fixed by the jack device, and the vehicle height does not fluctuate even if the loaded load suddenly increases or decreases during the cargo handling operation.

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 operation, and sets the air bellows to be slightly higher than the stored vehicle height. It is preferable that the jack device is contracted after supplying the working air to the vehicle to return the load of the vehicle body to the air suspension.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

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

As shown in FIG. 1, in the vehicle height lock device according to the present embodiment, a jack device 13 is provided on the outer surfaces of the left and right frames 1 directly above the rear axle 3 so as to be vertically expandable and contractable. The jack shaft 15 can protrude downward from the lower end of the main body portion 14 which is substantially attached to the outer surface of the frame 1 by bolting or the like.

FIG. 2 shows the detailed internal structure of the jack device 13 in a top view with the casing 16 cut away, and FIG. 3 shows the detailed internal structure of the jack device 13 with the casing 16 broken. 2 and FIG. 3, in the example shown in FIG. 2 and FIG.
The upper part of which is formed with an axial spline 1
5b are formed.

The screw 15a is screwed to a nut member 17 fixed to the bottom of the casing 16, and the spline 15b is held directly above the nut member 17 so as to be rotatable around the axis of the jack shaft 15. The rotating shaft 18 engages with the inner peripheral surface of the rotating shaft 18 and rotates together with the rotating shaft 18 so as to be guided vertically.

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

A gear 22 externally fitted to one end of the worm shaft 21 is meshed with a gear 24 of an output shaft of a motor 23 fixedly arranged at an upper part in the casing 16 via a fixture (not shown). The worm shaft 21 is rotated by the forward and reverse rotations of the motor 23 to rotate the jack shaft 15 together with the rotating shaft 18 via the worm gear 20 and the worm wheel 19, and the jack shaft 15 is connected to the screw screw 15 a and the nut member 17. Is operated to move up and down in the rotary shaft 18 by screwing.

Incidentally, reference numeral 25 in FIG.
Shows a limit switch for detecting that is completely stored.

As shown in FIG. 4, the jack device 13 configured as described above has a control valve 27 provided between each air bellows 5 and the air tank 26.
Control device 2 that controls vehicle 28 to adjust the vehicle height
9, the operation itself is controlled by a driver's manual operation by means of a 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 a motor load detection circuit 31. The motor load detection circuit 31 Motor 23 of device 13
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 provided in the driver's seat are also input to the control device 29, respectively.

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. The vehicle height memory switch 33 is provided with a plurality of vehicle heights ( (Corresponding to the platform height for each loading / unloading work place) into a plurality of switch positions so that the instruction can be selectively given to the control device 29 side.
Is such that a command to raise or lower the vehicle height to an arbitrary height can be given to the control device 29 side as necessary.

The control device 29 includes a detection signal from a vehicle height sensor 35 on the rear side 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.

In the control device 29, when the cargo handling operation is performed with the rear portion 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 has already been reduced. If the current vehicle height is lower than the height of the platform 10, when the current vehicle height is lower than the height of the platform 10, both the control valves 27 and 28 are opened. The 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 with respect to the air tank 26 side, and each air bellows 5 side is opened to the atmosphere, and each air bellows 5 is opened. , The working air is extracted from, and the height of the rear end of the carrier 11 and the height of the platform 10 are adjusted to match. If the platform height is not stored in the memory, the height of the platform
The driver adjusts the height of the platform 10 to match the height of the rear end. Thereafter, when the vehicle height fixing switch 30 is turned on, the jack device 13 is operated according to the control procedure shown in the flowchart of FIG.

That is, in step S1, when it is confirmed that the vehicle height fixing switch 30 is turned on, in the next step S2, the jack shaft 15 is moved toward the jack device 13.
Is output, whereby the motor 23 of the jack device 13 is rotated forward and the jack shaft 15 is extended.
Extend downward, and reach a state in which the tip of the jack shaft 15 is pressed against the upper surface of the axle 3, as shown by the two-dot chain line in FIG.

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

That is, the jack shaft 1 is mounted on the upper surface of the axle 3.
5, the motor 23 is overloaded because it cannot extend downward any more, and the current value consumed by the motor 23 rapidly increases in a stepwise manner. It detects that the extension of has stopped.

If the result of the determination in the previous step S3 is "Y
If "ES", the process proceeds to the next step S4, and the stop of the motor 23 of the jack device 13 is commanded. 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
, The control valves 27 and 28 are operated to start the discharge of the working 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 air bellows 5 so as not to drop below the minimum pressure capable of maintaining the function. To end the extraction.

In order to release the state in which 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, thereby adopting a control procedure as shown in the flowchart of FIG. First, in step S6, the vehicle height fixing switch 30
Is confirmed, in the next step S7, the current rear vehicle height is temporarily stored in the control device 29 based on the detection signal from the vehicle height sensor 35, and then, in step S8, Replenishment of the working air to the air bellows 5 is commanded, whereby the control valves 27, 2
8 is operated to start replenishment of working air from the air tank 26 to each air bellows 5.

In the next step S9, is the rear vehicle height detected by the vehicle height sensor 35 equal to the stored vehicle height in the previous step S7 + α (vehicle height slightly higher than the stored vehicle height)? Is determined, and the result of the determination is “YE
If "S", the flow proceeds to the next step S10, in which the supply 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 made. 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 to shorten and store 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, the jack shaft 15 is shortened upward, 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,
It is determined by the limit switch 25 of the jack device 13 whether the jack shaft 15 has been completely retracted,
If the result of the determination is "YES", the process proceeds to the next step S13, where the stop of the motor 23 of the jack device 13 is commanded. If the result of the determination in step S12 is "NO", The determination in step S12 is repeated.

Further, after the jack shaft 15 of the jack device 13 is completely retracted, in step S14, the operation air is discharged from each air bellows 5 in order to reduce the vehicle height by α added to the stored vehicle height. Then, the control valves 27 and 28 are operated to start the discharge of the working air from each air bellows 5, and the vehicle height is controlled to the vehicle height stored in the previous 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 increased when the cargo handling work is performed with the rear portion of the vehicle facing the platform 10. After adjusting the vehicle height by supplying and discharging working air to and from each air bellows 5 so as to match the height of the air bellows 5, the vehicle height fixing switch 30 is turned on, and the jack shaft 15 of the jack device 13 is extended. Then, the tip of the jack shaft 15 is pressed against the upper surface of the axle 3, and 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. As a result, the vehicle height is fixed.

When the cargo handling operation is completed, the vehicle height fixing switch 30 is turned off, and each air bellows 5 is turned off.
After the working air is replenished to return the load of the vehicle body 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 loading load suddenly increases or decreases during the cargo handling operation. Thus, the cargo handling work can be easily performed, and the work efficiency can be greatly improved.

Further, 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 5 to control the vehicle height to be constant, so that the consumption of the working air during the cargo handling work is reduced. And the capacity of the air tank 26 can be reduced.

The vehicle height lock device of 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. It is needless to say that various changes can be made within.

[0042]

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

(I) The load on the vehicle body is transferred from the air bellows to the jack device by extending the jack device during the cargo handling operation to extract the operating air from the air bellows, and the vehicle height is fixed by the jack device. The vehicle height can be maintained at a constant level even if the load suddenly increases or decreases during loading and unloading, making it possible to perform loading and unloading easily and greatly improve work efficiency. it can.

(II) Since the vehicle height does not fluctuate during the cargo handling operation, it is not necessary to supply and discharge the operating air to each air bellows to control the vehicle height constant, so that the consumption of the operating air during the cargo handling operation And the capacity of the air tank can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an example of an embodiment for implementing 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 details of the jack device of FIG. 1 with a part thereof cut away.

FIG. 4 is a block diagram showing a control system according to 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. 4;

FIG. 6 is a flowchart showing a control procedure at the time of fixing release by the control device of FIG. 4;

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 to a transport vehicle.

[Explanation of symbols]

 Reference Signs List 1 frame 3 axle 5 air bellows 9 transport vehicle 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

Claims (2)

[Claims] 1. A vehicle height lock device for preventing a vehicle height from fluctuating during a cargo handling operation in a transport vehicle equipped with an air suspension, wherein the jack device is configured to be vertically expandable and contractable between a frame and an axle. The jack device is attached to one of the frame and the axle, and the jack device is extended during loading and unloading, and the tip of the jack device is pressed against the other of the frame and the axle. After that, working air is extracted from the air bellows of the air suspension to reduce the load on the vehicle body. A vehicle height lock device comprising a control device for performing control so that the vehicle can be transferred to a vehicle. 2. The control device stores the current vehicle height fixed by the jack device at the end of the cargo handling operation and supplies the operating air to the air bellows so that the vehicle height is slightly higher than the stored vehicle height. 2. The vehicle height lock device according to claim 1, wherein the jack device is contracted to return the load of the vehicle body to the air suspension.