JPS62199509A - Ground clearance adjustment device - Google Patents

Abstract

PURPOSE:To ensure the positive affirmation of abnormality of a ground clearance detecting sensor where at least a part of suspension springs is composed of air springs by providing a warning by a warning means in case of abnormality of the ground clearance detecting sensor. CONSTITUTION:The rear front wheel 15 and the rear rear wheel 19 of a truck are suspended from a frame 13 by means of half springs 16 and 20 and air springs 17 and 21. And respective air springs 17 and 21 are communicated with each other by a communication pipe 23, and are connected with an automatic suction valve 27 and an automatic exhaust valve 28. And ground clearance is adjusted by a step of controlling respective valves 27 and 28 by a computer 40 based on the output from a ground clearance detecting sensor 56 and the like. In this case, it is judged whether the output from the ground clearance detecting lamp turn on an off in case of abnormality. In this constitution, a driver is informed of abnormality of the ground clearance detecting sensor 56 for taking a proper action.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention relates to a vehicle height adjustment device, and more particularly to a vehicle height adjustment device in which at least a portion of a suspension spring is composed of an air spring, and in which air is supplied and discharged to and from the air spring electronically. The present invention relates to a height adjustment device for a vehicle, which adjusts the height by controlling a control device.

KSummary of the Invention According to the present invention, if an abnormality occurs in a vehicle height detection sensor provided in a vehicle height adjustment device, an alarm is issued by an alarm means.

K Prior Art: At least a portion of a truck's suspension spring is made up of an air spring, and the height of a loading platform is adjusted by supplying air to the air spring or discharging air from the air spring. becomes possible. Furthermore, the supply and discharge of this air is controlled by an electronic control device such as a microcomputer, and
By setting the height of the loading platform to an arbitrary height using a push button, it is possible to eliminate the level difference between the platform and the loading platform, making loading and unloading of cargo easier.

Problem 1 to be Solved by the K Invention This type of vehicle height adjustment device requires a vehicle height detection sensor for detecting the value of the adjusted vehicle height. This vehicle height detection sensor constitutes an important part of the vehicle height adjustment device, and if this vehicle height detection sensor fails, the vehicle height adjustment function will be lost.

However, conventional vehicle height adjustment devices do not have any means for detecting failure of the vehicle height detection sensor or for warning of this failure. Therefore, there is a problem in that the driver or operator does not notice any abnormality in the vehicle height detection sensor.

The present invention has been made in view of these problems, and provides a vehicle height sensor that can immediately notify the driver or operator when an abnormality occurs in the vehicle height detection sensor. The object is to provide an adjustment device.

Means for Solving Problem K] As shown in FIG. 1, the present invention is such that at least a part of the suspension spring is composed of an air spring, and the supply and discharge of air to the air spring is controlled by an electronic control device. The device is configured to adjust the height by adjusting the vehicle height, and is provided with a sensor for detecting the vehicle height and an alarm means, and the alarm means issues an alarm if an abnormality occurs in the vehicle height detection sensor. be.

[K effect] Therefore, according to the present invention, when an abnormality occurs in the vehicle height detection sensor, the driver or operator is notified of the abnormality by the i-information means, and the malfunction of the vehicle height detection sensor can be detected. This enables reliable recognition.

(Example] The present invention will be explained below with reference to an illustrated embodiment.

FIG. 2 is a block diagram showing a truck bed height adjustment device according to an embodiment of the present invention, in which the 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 attached between the rear front shaft 15 and the frame 13. Similarly, the rear axle 19 is suspended on the frame 13 by a leaf spring 20 and an air spring 21, and the rear axle 19 and the frame 13
A shock absorber 22 is interposed between the two.

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, 21 are connected to an automatic air supply valve 27 and an automatic exhaust valve 2B via supply and exhaust pipes 26, respectively.

Furthermore, this truck is equipped with a compressor 29.

The compressor 29 is connected to the wet tank 3°, and the wet tank 30 is connected to the protection valve 3.
It is connected to the reservoir tank 32 via 1. And the reservoir tank 32 is yet another reservoir tank 33
It is also connected to the automatic air supply valve 27 via the 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 automatic air supply valve 27, the automatic exhaust valve 28,
The actuators 37 and 38 provided on the shock absorbers 18 and 22, respectively, and the cab suspension shock absorber 39 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 a manual operation button 42 for manually adjusting the vehicle height and a mode selection button 43 for selecting a vehicle height adjustment mode. Further, this panel 41 is provided with an operating lamp 44, which blinks in response to an output signal from the microcomputer 40. Further, a cab suspension changeover switch 48 and an air suspension changeover switch 49 are provided on the instrument panel of the cab of this truck, and these switches 48 and 49 are also connected to the input side of the microcomputer 40.

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.

A bottoming detection sensor 5 is provided between the front axle 11 and the frame 13 to detect bottoming from the distance between them.
3 is provided, and also a microcomputer 40
connected to the input side of the The parking brake lever 60 is also provided with a parking brake sensor 61, the output of which is input to 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, a warning buzzer 58, and an alarm buzzer 59 are connected to the output side of the microcomputer 40, respectively. These lamps 57 and buzzers 58 and 59 are both attached to the instrument panel of the 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 causes the automatic exhaust valve 28 to open. The air in the air spring 17.21 is then exhausted through the exhaust valve 28, thereby lowering the height of the cargo platform.

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 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 load.

When the load is small, the magnetic valve 24 is opened and the surge tank 25 and the air spring 17.21 are communicated with each other to lower the spring constant of the suspension device.

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 shock absorber 18. 22 is strongly throttled to increase its damping force, and the suspension device is maintained in an optimal state according to the load amount.

In the apparatus for adjusting the height of the loading platform in this manner, the height of the loading platform is detected by the vehicle height detection sensor 56 as described above. This sensor 56 is a very important component, and if this sensor 56 fails, the vehicle height adjustment function will be lost. So this sensor 5
6 is out of order, an alarm is issued as shown in FIG. That is, the microcomputer 40 reads the output of the vehicle height detection sensor 56, determines whether the output is being generated normally, and, if an output is present, further determines whether the output is an abnormal value. . If the power line or signal line connected to the sensor 56 is disconnected, the sensor 56 will no longer generate an output. Alternatively, if a failure occurs in the sensor 56, its output becomes an abnormal value.

The relationship between the vehicle height and the output of the vehicle height detection sensor 56 is as shown in the graph in FIG. 5. When the vehicle height is between the upper limit and the lower limit, the output of the vehicle height detection sensor 56 is 0.8V~
3. It is within the range of Ov and is judged to be within the normal usage range. On the other hand, if an output value outside the above range is generated, it is determined that the output of the vehicle height detection sensor 56 is abnormal. When the vehicle height detection sensor 56 does not generate an output or when the output of the vehicle height detection sensor 56 is abnormal, the microcomputer 40 activates the warning lamp 57 provided on the cab 47 and the operation lamp provided on the control panel 41. 44 will be flashing. Therefore, these lamps 57 and 44 make it possible to notify the driver or operator of an abnormality in the vehicle height detection sensor 56. This allows the driver or operator to reliably recognize the abnormality of the vehicle height detection sensor 56,
Appropriate measures can then be taken.

Effects of the Invention Therefore, according to such a configuration, it is possible to make the driver or the like reliably recognize the abnormality of the vehicle height detection sensor.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the gist of the present invention, FIG. 2 is a block diagram showing a truck bed height adjustment device according to an embodiment of the present invention, and FIG. 3 is a block diagram showing the operation of loading bed height adjustment. FIG. 4 is a flowchart showing an alarm operation in response to a failure of the vehicle height detection sensor, and FIG. 5 is a graph showing changes in the output voltage of the sensor with respect to the vehicle height. In addition, in the symbols used in the drawings, 17.21... Air spring 27... Automatic air supply valve 28... Self-help exhaust valve 40... Microcomputer 44... Operating lamp 56... Vehicle height detection Sensor 57...◆Warning lamp.

Claims (1)

[Claims] In a device in which at least a part of the suspension spring is 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, the device includes a sensor for detecting vehicle height; , an alarm means, and the alarm means issues an alarm when an abnormality occurs in the vehicle height detection sensor.