JPS61263819A - Level-control device for vehicles - Google Patents

Abstract

PURPOSE:To make level control by manual operations performable, by installing a level controlling electronic control unit and independent manual feed and exhaust valves, in case of a device which uses at least a part of suspension springs for an air spring and thereby makes the level control performable. CONSTITUTION:A rear front shaft 15 and a rear rear shaft 19 of a truck are suspended on leaf springs 16 and 20 whose rear end is bent downward each, while each end of these leaf springs 16 and 20 is suspended on a frame 13 by air springs 17 and 21 and shock absorbers 18 and 22. Each of these air springs 17 and 21 is connected to an automatic feed valve 27 and an automatic exhaust valve 28 being controlled by a microcomputer 40, via a feed-exhaust pipe 26, making automatic control performable. And, a feed valve 35 and an exhaust valve 36 of manual type are installed in a branch pipe branching off from the feed pipe extending out of reservoir tanks 32 and 33 and leading to an interconnecting pipe 23, and at the time of trouble in the microcomputer 40, the level control is made so as to be performable by manual operation.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to a vehicle height adjustment device that adjusts the height of a vehicle by electronic control. Summary of the Invention The present invention provides a vehicle in which at least a portion of a suspension spring is an air spring, and air is supplied to or discharged from the air spring while being controlled by an electronic control device. An electronic control device and an independent manual air supply valve and exhaust valve are provided,
These intake valves and exhaust valves enable manual height adjustment of the vehicle in the event that the electronic control unit fails.

[Prior art 1] For example, by constructing a suspension spring that suspends the rear axle of a truck from a leaf spring and an air spring, and in particular electronically controlling the supply and discharge of air to the air spring, the height of the truck bed can be increased. It becomes possible to perform electronic control of the adjustment. In particular, by configuring the electronic control device from a microcomputer, the set values can be changed arbitrarily, making it possible to hold the loading platform at an arbitrary height. [Problems to be Solved by Invention K] However, in such an electronically controlled cargo bed height adjustment device, for example, if the microcomputer that makes up the electronic control device breaks down, the height adjustment of the truck bed cannot be performed. will no longer be carried out. And at this time, what is the height of the loading platform? ! ! If it is too high or too low at the edge, it will hinder your driving. The present invention has been made in view of these problems, and provides a device that can restore the height of the vehicle to a state in which it can be driven by manual operation even if the electronic control device fails. The purpose is to provide

[Means to solve the problem]

The present invention provides a vehicle in which at least a portion of a suspension spring is constituted by an air spring, and height adjustment is performed by controlling the supply and discharge of air to the air spring by an electronic control device. A manual air supply valve and an exhaust valve are provided which are independent from the device. Therefore, according to the present invention, if the electronic control device malfunctions, it becomes possible to manually adjust the height of the vehicle using the manual air intake valve or exhaust valve, thereby allowing the vehicle to continue running. It is possible to restore the height. K Embodiment The present invention will be described below with reference to an illustrated embodiment. FIG. 1 is a block diagram showing a truck bed height adjustment device according to an embodiment of the present invention, in which a front axle 11
is suspended from a frame 13 via leaf springs 12. A shock absorber 14 is interposed between the front shaft 11 and the frame 13. On the other hand, the rear and front shafts 15 are suspended from the frame 13 by leaf springs 16, and the rear ends of the leaf springs 16 are bent downward, and are supported by air springs 17. ing. A shock absorber 18 is also installed between the leaf spring 16 and the frame 13. Similarly, the rear axis 19
is suspended on the frame 13 by a leaf spring 20 and an air spring 21, and a shock absorber 2 is provided between the leaf spring 20 and the frame 13.
2 is interposed. The air springs 17.21 provided corresponding to the rear-front shaft 15 and the rear-rear shaft 19 are communicated with each other through a communication pipe 23, and these pair of air springs 17.21 are connected through a magnetic valve 24. and is connected to the surge tank 25. Note that the left and right air springs 17, 21 are independent from each other, and each is provided with 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 supply and exhaust pipes 26, respectively. Furthermore, this truck is equipped with a compressor 29. The compressor 29 is connected to a wet tank 30, and the wet tank 30 is connected to a reservoir tank 32 via a protection valve 31. And the reservoir tank 32 is yet another reservoir tank 3
3, and is also connected to the automatic air supply valve 27 via a check valve 34. Furthermore, this check valve 34 is connected to a pair of air springs 17, 21 via a manually operated air supply valve 35. A manual exhaust valve 36 is connected to the manual air supply valve 35 . The above automatic air supply valve 27 and automatic exhaust valve 28
, the actuators 37 and 38 provided on the shock absorbers 18 and 22, and the shock absorber 39 for the suspension suspension are controlled by a microcomputer 40 constituting an electronic control device. A control panel 41 is connected to the input side of this microcomputer 40. This panel 41 is attached to the rear end of the gate on the right side of the loading platform. 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. Further, this panel 41 is provided with a display lamp 46, which blinks in response to an output signal from the microcomputer 40. Furthermore, there is a cab suspension changeover switch 4 on the instrument of the cab of this truck.
8. An air suspension changeover switch 49 is provided, and these switches 48 and 49 are also controlled by the microcomputer 40.
connected to the input side of the Further, the transmission 50 of this truck is provided with a gear position detection sensor 51 and a vehicle speed detection sensor 52, respectively, and the outputs of these sensors 51 and 52 are also input to the microcomputer 40. Further, a bottoming detection sensor 53 is provided between the front wheel 11 and the frame 13 to detect bottoming from the distance between the two, and is also connected to the input side of the microcomputer 40. On the other hand, the air supply and exhaust pipes 26 of the air springs 17.21 constituting the rear suspension device are provided with live load detection sensors 54.55 that detect the live load from the pressure of these air springs 17.21. There is. These sensors 54 and 55 perform detection operations using different pressures, and are both connected to the input side of the microcomputer 40. Further, a vehicle height detection sensor 56 is provided between the rear axle 19 and the frame 13 to detect the vehicle height from the distance between the two, and is similarly connected to the input side of the microcomputer 40. A warning lamp 57 and a warning buzzer 58 are connected to the output side of the microcomputer 40, respectively. These lamps 57 and buzzers 58
Both are attached to the instrument panel of cab 47. Next, the operation of the truck bed height adjusting device having the above configuration will be explained. The operation of setting the loading platform to the standard height is performed by the microcomputer 40 based on the flowchart shown in FIG. That is, the microcomputer 40 controls the vehicle height detection sensor 5.
In addition to reading the detection output of No. 6, a standard value preset in the microcomputer 40 is also 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 spring 17.21 will be exhausted through this exhaust valve 28, thereby lowering the height of the loading platform. 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 tank 32.33 is supplied to the air spring 17.21 through the air supply valve 27 to raise the cargo platform. In addition, if the actual vehicle height and the standard value match, the air intake valve 27
, and exhaust valve 28 are both held closed. In this way, it is possible to always hold the loading platform in a predetermined position. Note that the standard value is stored in the microcomputer 40 as a value with a predetermined width. Furthermore, in this truck, the spring constant and damping force of the suspension device are changed depending on the amount of load on the platform. The load on the loading platform is detected in stages by load detection sensors 54 and 55 consisting of pressure sensors.
．． The microcomputer 40 reads the detection output of 55. The magnetic valve 24 is then opened and closed depending on the loading amount. When the load m is small, the magnetic valve 24 is opened, the surge tank 25 and the air spring 17.21 are communicated with each other, and the spring constant of the suspension device is lowered. At the same time, the control signal from the microcomputer 40 causes the actuators 37, 38 to increase the aperture diameter of the shock absorber 18, 22 to reduce its damping force. On the other hand, if a large load is detected by the sensor 54.55, the magnetic valve 24 is closed to increase the spring constant of the air spring 17.21, and the actuator 37.38 is activated to reduce the shock absorber 18.22. This is done to increase the damping force and maintain the suspension system in an optimal condition depending on the load. Further, in this truck, the air suspension changeover switch 49 provided on the instrument panel of the cab 47 allows the suspension's ° characteristics to be changed manually. In this case, the characteristics of the suspension device can be selected by the switch 49 in preference to the electronic control by the microcomputer 40. Therefore, when transporting something somewhat heavy, it is sufficient to switch the suspension to "hard" using this switch 49. In this way, the magnetic valve 24
is closed and the shock absorber 17.22
The damping force is increased, making it possible to improve driving stability. Furthermore, in this vehicle, the vehicle speed is detected by the vehicle speed sensor 52, and this value is 100km/h.
When the speed exceeds 1I/h, the suspension is automatically switched to "hard", thereby increasing stability during high-speed driving. Furthermore, in this truck, as shown in Figure 1,
A manual air supply valve 35 and a manual exhaust valve 36 are each provided. Therefore, in the event that the microcomputer 40 or the actuator controlled by the microcomputer 40 fails, the vehicle height can be adjusted using these manual valves 35 and 36. In other words, in the event that the electronic control device malfunctions when the loading platform is at an abnormally low position, the manual air supply valve 35 can be opened, and the compressed air in the reservoir tanks 32 and 33 can be transferred through the air supply valve 35. The springs 17.21 can be fed and the bed can be returned to approximately its standard height. In addition, if the electronic control device malfunctions when the loading platform is at an abnormally high position, all you have to do is close the air intake valve 35 and open the exhaust valve 36.
As a result, the air in the air springs 17.21 is expelled and the cargo platform is lowered to approximately its standard height. Note that in the event that the electronic control device malfunctions, the automatic air supply valve 27 and the automatic exhaust valve 28 are both closed by built-in return springs, so that the above-mentioned manual operation is not hindered. [Effects of the Invention] As described above, the present invention provides an electronic control device and an independent manual air supply valve and exhaust valve. Therefore, according to the present invention, if the electronic control device fails,
Using these manual air supply valves or exhaust valves, the vehicle body can be raised or lowered to a desired height, and the vehicle body can be restored to a running state. Therefore, even in the event of a failure of the electronic control device, it is possible to run the vehicle.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a truck bed height adjustment device according to an embodiment of the present invention, and FIG. 2 is a flowchart showing the operation of height adjustment of the truck bed. In addition, in the symbols used in the drawings, 17.2 Air spring 27...Automatic air supply valve 28...Automatic exhaust valve 35...Manual air supply valve 36...Manual exhaust Valve 40...Microcomputer 56...Vehicle height detection sensor.

Claims (1)

[Claims] In a vehicle in which at least a part of the suspension spring is composed of an air spring, and the height is adjusted by controlling the supply and discharge of air to the air spring by an electronic control device, there is provided a vehicle that is independent of the electronic control device. A vehicle height adjustment device characterized by being provided with a manual air supply valve and an exhaust valve.