JPH0623006B2 - Truck bed height adjuster - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a height adjusting device for a truck bed, and in particular, a part of a suspension spring of a rear shaft is composed of an air spring. The present invention relates to a height adjustment device for a bed of a truck, in which the height of the bed is adjusted by controlling the supply and discharge of the same by an electronic control device.

[Outline of Invention]

According to the present invention, a manual operation means is attached to a rear portion of a truck bed, and the height is adjusted to a desired value by the manual operation means, and the height adjusted at this time is set as a set value. The height is automatically adjusted by an electronic control unit so that it is kept in this set value, and it is irrespective of the load when loading or unloading luggage. The loading platform is always kept at a constant height.

[Conventional technology]

In order to adjust the height of the loading platform, for example, in a conventional tractor, the air spring and the air tank are connected via a leveling valve, and the vehicle height or the loading platform height is adjusted by this leveling valve. Was there. Therefore, when a large load is applied to the bed, air is supplied to the air spring, and when the load is reduced, the air in the air spring is discharged, and the height of the bed is adjusted. .

[Problems to be solved by the invention]

In such a conventional height adjusting device using a leveling valve, in order to maintain the height of the loading platform at a constant value, it is necessary to manually operate the control lever of the leveling valve to adjust the loading platform height. Become. Then, by completely closing this leveling valve in a predetermined state, the supply of air to the air spring and the discharge of air from the air spring are both blocked, and the bed is held at a constant height. It becomes possible.

However, according to such height adjustment, the flexure amount of the air spring changes depending on the load loaded on the cargo bed, and thus the height of the cargo bed automatically changes. Therefore, according to such a device, a step is likely to occur between the platform and the platform, and there is a possibility that the loading and unloading work of the platform cannot be performed smoothly.

The present invention has been made in view of the above problems, and holds the cargo bed at a desired height by a manual operation and automatically adjusts the height to this value. It is intended to provide a height adjusting device.

[Means for solving problems]

According to the present invention, a suspension spring for suspending a rear shaft is composed of a leaf spring, one end of the leaf spring is rotatably attached to a frame, and the other end of the leaf spring is bent downward and bent downward. An air spring is interposed between the other end and the frame, and an automatic air supply valve for supplying compressed air into the air spring and an automatic exhaust valve for discharging compressed air from the air spring are controlled by an electronic control unit. The height of the bed is adjusted by controlling the opening and closing, and a manual operation means is attached to the rear part of the bed, and the automatic air supply valve or the automatic exhaust valve is operated by the manual operation means via the electronic control unit. Is opened and closed to adjust the height of the bed to a desired value, and when the plurality of buttons of the manual operation means are pressed, the electronic control The device closes the automatic air supply valve and the automatic exhaust valve to stop all operations, connects a switch provided in the cab with the electronic control device, and switches the switch in the cab to the manual operation. The operation means is prioritized, the height adjusted by the operation of the manual operation means is stored as a set value, and the height is automatically adjusted by the electronic control unit so as to be maintained at this set value. The present invention relates to a device for adjusting the height of a bed of a truck, which is characterized by being performed.

[Action]

When the manual operation means provided on the rear side of the truck bed is operated, the automatic air supply valve or the automatic exhaust valve is controlled to open and close through the electronic control unit, thereby supplying compressed air into the air spring. Alternatively, or by expelling compressed air from the air spring, the height of the bed can be adjusted to the desired value. That is, the height of the platform is made to match the height of the platform, for example.

Then, the height adjusted at this time is stored as a set value. Then, when loading and unloading the load between the truck bed and the platform, if the load on the truck bed changes and the height of the truck bed changes, the electronic control unit sets the above setting value. The automatic air supply valve or the automatic exhaust valve is now controlled to open and close, and by controlling the air supply to the air spring and the air discharge from the air spring, the height of the platform can be automatically adjusted to the above setting value. Will be adjusted to.

When a plurality of buttons of the manual operation means for setting the set value are pressed, the electronic control unit closes the automatic air supply valve and the automatic exhaust valve to stop all the operations. This prevents chattering of the height adjustment of the carrier. In addition, the switch installed in the cab is OF
When it is set to F, the switch has priority over the manual operation means in this cab, so that the electronic control unit closes the automatic air supply valve and the automatic exhaust valve to stop all operations and ensure safety. It will be.

〔Example〕

 The present invention will be described below with reference to an embodiment shown in the drawings.

FIG. 1 is a block diagram showing a height adjusting device for a bed of a truck according to an embodiment of the present invention.
Is suspended from the frame 13 via a leaf spring 12. A shock absorber 14 is interposed between the front shaft 11 and the frame 13. On the other hand, the rear front shaft 15 is suspended on the frame 13 by the leaf spring 16, and the rear end portion of the leaf spring 16 is bent downward, and the rear end portion is supported by the air spring 17. ing. A shock absorber 18 is also attached between the leaf spring 16 and the frame 13. Similarly, rear rear shaft 19
Is suspended on the frame 13 by the leaf spring 20 and the air spring 21, and the shock absorber 2 is interposed between the leaf spring 20 and the frame 13.
2 is installed.

The air springs 17 and 21 provided respectively corresponding to the rear front shaft 15 and the rear rear shaft 19 are communicated with each other by a communication pipe 23, and the pair of air springs 17 and 21 includes a magnetic valve 24. It is connected to the surge tank 25 via. The left and right air springs 17 and 21 are independent of each other, and each has a separate surge tank 25. The left and right air springs 17 and 21 are connected to an automatic air supply valve 27 and an automatic exhaust valve 28 via a supply / exhaust pipe 26, respectively.

Furthermore, the truck is equipped with a compressor 29.
The compressor 29 is connected to the wet tank 30, and the wet tank 30 includes the protection valve 3
1 to the reservoir tank 32. Then, the reservoir tank 32 is a different reservoir tank 33.
It is also connected to the automatic air supply valve 27 via the check valve 34. Further, the check valve 34 is connected to a pair of air springs 17 and 21 via a manual air supply valve 35.
A manual exhaust valve 36 is connected to the manual air supply valve 35. The automatic air supply valve 27, the automatic exhaust valve 28,
The actuators 37 and 38 and the cabsus shock absorber 39 provided on the shock absorbers 18 and 22, respectively, are controlled by a microcomputer 40 that constitutes an electronic control unit.

A control panel 41 is connected to the input side of the microcomputer 40. This panel 41 is attached to the rear end of the gate on the right side of the luggage carrier. The panel 41 is provided with an up button 42, a down button 43, a restore button 44, and an emergency stop button 45, respectively. A display lamp 46 is provided on the panel 41 so as to blink according to an output signal from the microcomputer 40. Furthermore, on the instrument of the cab of this truck, the cab suspension switch 4
8. An air suspension changeover switch 49 is provided, and these switches 48 and 49 are also the microcomputer 40.
Is connected to the input side of.

A gear position detection sensor 51 and a vehicle speed detection sensor 52 are provided in the transmission 50 of the truck, and the outputs of these sensors 51 and 52 are also input to the microcomputer 40.
Further, between the front shaft 11 and the frame 13, a bottoming detection sensor 5 for detecting bottoming from a distance between the front shaft 11 and the frame 13.
3 is also provided, and the microcomputer 40 is also provided.
Is connected to the input side of.

On the other hand, the supply / exhaust pipes 26 of the air springs 17 and 21 constituting the rear suspension device are provided with load detection sensors 54 and 55 for detecting the load from the pressure of these air springs 17 and 21. There is. These sensors 54 and 55 are designed to perform detection operations at different pressures, and are both connected to the input side of the microcomputer 40. Further, a vehicle height detection sensor 56 for detecting the vehicle height from the distance between the rear and rear axles 19 and the frame 13 is provided, and similarly connected to the input side of the microcomputer 40. A warning lamp 57 and a warning buzzer 5 are connected to the output side of the microcomputer 40. Both the lamp 57 and the buzzer 58 are attached to the instrument panel of the cab 47.

Next, the operation of the height adjusting device for the bed of the truck according to the above configuration will be described. The operation of setting the platform to the standard height is performed by the microcomputer 40 based on the flowchart shown in FIG. That is, the microcomputer 40 uses the vehicle height detection sensor 5
In addition to reading the detection output of 6, the standard value preset in the microcomputer 40 is read, and the actual vehicle height is compared with the standard value. If the actual vehicle height is higher than the standard value, the microcomputer 4
0 opens the automatic exhaust valve 28. Then, the air in the air springs 17 and 21 is discharged through the exhaust valve 28, thereby lowering the height of the cargo bed.

On the other hand, if the actual vehicle height is lower than the standard value,
The automatic air supply valve 27 is opened, and the compressed air stored in the reservoir tanks 32 and 33 is supplied to the air springs 17 and 21 through the air supply valve 27 to raise the loading platform. If the actual vehicle height matches the standard value, the air supply valve 2
7 and the exhaust valve 28 are both kept closed. In this way it is possible to keep the platform always in place. The standard value is stored in the microcomputer 40 as a value having a predetermined width.

Further, in this truck, the spring constant and the damping force of the suspension device are changed according to the loading amount on the loading platform. The load on the platform is detected stepwise by load detection sensors 54 and 55 which are pressure sensors.
The microcomputer 40 reads the detection output of 55.
Then, the magnetic valve 24 is opened and closed according to the loading amount.

When the loading amount is small, the magnetic valve 24 is opened and the surge tank 25 and the air springs 17 and 21 are communicated with each other to reduce the spring constant of the suspension device.
At the same time, the actuators 37 and 38 increase the throttle diameter of the shock absorbers 18 and 22 and decrease the damping force thereof by the control signals from the microcomputer 40. On the other hand, when a large load is detected by the sensors 54 and 55, the magnetic valve 24 is closed to increase the spring constants of the air springs 17 and 21, and the actuators 37 and 38 cause the shock absorbers 18 and 22 to move. Is strongly squeezed to increase its damping force, and the suspension device is maintained in an optimum state according to the load capacity.

Next, an operation for setting the loading platform of this truck to an arbitrary height and automatically adjusting so as to always maintain the set height will be described. This operation is performed based on the flowchart shown in FIG. That is, the microcomputer 40 reads the outputs of the switches linked to the up button 42 and the down button 43 of the control panel 41, and opens the automatic air supply valve 27 or the automatic exhaust valve 28 by these outputs, respectively. Alternatively, the height of the bed is manually adjusted based on the manual operation of the lowering button 43. This operation is performed by releasing the finger from the up button 42 or the down button 43 and closing the air supply valve 27 or the exhaust valve 28 when the corresponding switch is closed.

In this way, the buttons 42, 43 of the control panel 41 are
The manual operation allows the loading platform to be moved to an arbitrary height, which eliminates the step between the loading platform and the loading platform and enables loading and unloading of luggage. Further, at the same time as the above operation is completed, as shown in FIG.
The detection output of is read and this detection output is stored in the register as a set value. After that, the microcomputer 40
Adjusts the height of the loading platform based on this set value.

This height adjustment operation is an operation in which the standard value in FIG.
Compares the actual height of the cargo bed with the set value, and if there is a gap between the two, opens the automatic air supply valve 27 or the automatic exhaust valve 28, respectively, and supplies air to the air springs 17 and 21. By supplying or exhausting air from these air springs 17 and 21, the above-mentioned vehicle height is maintained.

As described above, according to the height adjustment device for a truck bed according to the present embodiment, not only the height of the truck bed is adjusted to a standard value, but also the height of the truck bed is set to a desired value set by a manual operation. The height of the loading platform is electronically controlled by the microcomputer 40 so that the loading platform height is maintained at this value while being changed. Therefore, while loading and unloading luggage between the platform and the bed, the load applied to the bed changes and the air spring 17,
When the amount of deflection of 21 changes, air is supplied and discharged so as to cancel this change, and control is performed so that the platform and the bed are always aligned.
Therefore, this makes it possible to provide a truck that can easily carry out the loading and unloading work of the loading platform.

Further, the control panel 41 is provided with a restore button 44 in addition to the up button 42 and the down button 43. Therefore, if two or more buttons are pressed by mistake, there is a possibility of malfunction or chattering. In order to prevent these, all operations are stopped. This operation will be described with reference to FIG.
0 reads the outputs of the switches corresponding to the up button 42, the down button 43, and the restore button 44, and stores the outputs of these switches in the registers b ₀ , b ₁ , and b ₂ , respectively. Then, the values stored in b _{0 to} b ₂ of this register are added, and it is determined whether the value is 2 or more. 2 or less, that is, 2 or more switches O
If it is not N, normal raising, lowering, or restoring operation is performed. On the other hand, when the added value is 2 or more and two or more switches are in the ON state, the operation is stopped. When not in operation, the output signal of the switch is ignored and operation is not performed. Therefore, malfunction and chattering are prevented by this, and safety is improved.

Furthermore, in this truck, as described above, the cab 47 is used.
An instrument panel changeover switch 49 is provided. The above vehicle height adjusting operation is performed only when the switch 49 is switched to the vehicle height adjusting position. That is, the changeover switch 49 in the driver's seat has priority over the operation of the control panel 41.

This operation will be described with reference to FIG. 5. The microcomputer 40 reads the output of the switch 49 at the driver's seat, and at the same time determines whether or not the switch is ON and the vehicle height can be adjusted. When the switch is OFF, the raising, lowering, and restoring operations are stopped. Further, even if the control panel 41 is operated while this switch is OFF, the operation is canceled. Change switch 4
When 9 is ON, the outputs of the switches corresponding to the up button 42, the down button 43, and the restore button 44 are read, and the operation corresponding thereto is performed.

Therefore, according to such a configuration, by turning off the switch 49 in the cab 47, the vehicle height adjustment operation is not performed, and the safety can be improved. Although the changeover switch 49 is also used as a switch for changing the hardness of the suspension, these may be provided separately from each other.

[Invention effect]

As described above, according to the present invention, the manual operation means is attached to the rear portion of the luggage carrier, and the manual operation means controls the opening and closing of the automatic air supply valve or the automatic exhaust valve through the electronic control unit to increase the height of the luggage carrier. The height is adjusted to a desired value, the height adjusted at this time is stored as a set value, and the height is automatically adjusted by the electronic control unit so as to maintain the set value. It is the one.

Therefore, according to the present invention, the height of the loading platform can be adjusted by the manual operation means attached to the rear portion of the loading platform, and when loading and unloading the luggage between the loading platform and the platform, the loading platform can be loaded. It is possible to make height adjustments so that the height of the is equal to the height of the platform. Moreover, by storing the height set at this time as a set value, the electronic control unit controls the automatic air supply valve and the automatic exhaust valve to supply compressed air into the air spring or to supply compressed air from the air spring. By discharging, the height of the loading platform will automatically be maintained at the set height. Therefore, the height of the bed does not change due to changes in load. This makes loading and unloading work easier and improves safety.

Moreover, when a plurality of buttons of the manual operation means for setting the height of the loading platform are pressed, the electronic control unit closes both the automatic air supply valve and the automatic exhaust valve to stop all operations. I have to. Therefore, a malfunction due to the manual operation means is prevented, and chattering is prevented from occurring in the height adjustment of the loading platform. Moreover, since the switch in the cab, which has priority over the manual operation means, is connected to the electronic control unit, the vehicle height adjustment operation may be performed by switching the switch in the cab to the stop side. Therefore, it is possible to provide an extremely safe loading platform height adjusting device.

Further, according to the present invention, one end of a leaf spring constituting the suspension spring is rotatably attached to the frame, and the other end of the leaf spring is bent downward so that the other end bent downward and the frame. Since an air spring is installed between the air springs and the height is adjusted by supplying and discharging air to and from the air springs, it is possible to reduce the distance between the rear shaft and the frame. In this state, the vehicle height can be kept low, and a device for adjusting the vehicle height can be compactly incorporated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a height adjusting device for a bed according to an embodiment of the present invention, FIG. 2 is a flow chart showing a normal vehicle height adjusting operation, and FIG. FIG. 4 is a flowchart showing an operation for changing and storing this value as a set value, FIG. 4 is a flowchart for prohibiting the operation when two or more buttons are pressed, and FIG. 2 is a flowchart for prioritizing and improving safety. In the reference numerals used in the drawings, 15: rear front shaft 16, 20 ... leaf spring 17, 21 ... air spring 19 ... rear rear shaft 27 ... automatic air supply valve 28 ... automatic exhaust valve 40 ... Microcomputer 41 ... Control panel 42 ... Up button 43 ... Down button 49 ... Changeover switch 56 ... Vehicle height detection sensor

Claims (1)

[Claims] 1. A suspension spring for suspending a rear shaft is constituted by a leaf spring, one end of the leaf spring is rotatably attached to a frame, and the other end of the leaf spring is bent downward and bent downward. An electronic control device includes an air spring interposed between the other end and the frame, and an automatic air supply valve for supplying compressed air into the air spring and an automatic exhaust valve for discharging compressed air from the air spring. The height of the bed is adjusted by controlling the opening and closing by means of a manual operation means attached to the rear part of the bed, and the automatic air supply valve or the automatic exhaust valve is operated by the manual operation means via the electronic control unit. The valve is opened / closed to adjust the height of the bed to a desired value, and the electronic device is operated when a plurality of buttons of the manual operation means are pressed. The control device closes the automatic air supply valve and the automatic exhaust valve to stop all the operations, connects the switch provided in the cab with the electronic control device, and switches the switch in the cab to the above The manual operation means is prioritized, the height adjusted by the operation of the manual operation means is stored as a set value, and the height is automatically adjusted by the electronic control device so as to be maintained at this set value. A height adjustment device for a truck bed, which is characterized in that