JP2001047834A - Vehicle level correcting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a frame and various objects mounted on it at a horizontal state by controlling the stroke of hydraulic cylinders suspending wheels with a control device based on the signals from height sensors and a clinometer. SOLUTION: The rear section of the frame 2 of a crane vehicle 1 is supported by the left hydraulic cylinder 4 and right hydraulic cylinder 5 of a rear axle. A road surface 21 is inclined by an angle α against the horizontal plane, and the left hydraulic cylinder 4 is extended and the right hydraulic cylinder 5 is shrunk to keep the frame 2 nearly horizontal. Height sensors 31 and a clinometer 29 are fitted to the frame 2 and are connected to a control device 35 by electric circuits respectively. The hydraulic cylinders 4, 5 are extended or shrunk for a horizontality adjustment to keep the frame 2 of the vehicle 1 horizontal based on the predetermined reference by receiving the signals from the height sensors 31 and clinometer 29.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle leveling device in which a working vehicle, a truck or the like having a hydraulic suspension device holds a vehicle horizontally for a predetermined work or load.

[0002]

2. Description of the Related Art For example, a vehicle having a hydraulic suspension device, which is provided with a control device for controlling a distance between a frame and an axle within a predetermined dimension, is known.

[0003] However, the above technique does not take into account tires and other flexures. Further, the relationship between the vehicle and the ground is such that the frame is maintained at a predetermined distance from the ground on which the vehicle stops, so that if the ground is inclined, the upper surface of the frame is also inclined. And
Since it is mounted parallel to the frame, the mounted object or the upper object on the frame will also be inclined.

[0004] Ladder fire trucks and crane trucks are equipped with means for correcting the inclination between the frame and the upper object, for example, gyro rings and the like, so that their bases are held horizontally regardless of the inclination of the vehicle. ing. However, the center of gravity of the vehicle and the center of attachment of the upper object are unbalanced when the vehicle is stopped on an inclined ground for work. Therefore, in the case of a ladder truck or a crane truck, even if the outrigger is set, the limit inclination angles of the ladder and the boom differ depending on the turning direction, and there is a possibility that a problem may occur in work safety. Further, if the outrigger is set to keep the frame and the upper object horizontal, the vehicle cannot travel.

Japanese Patent Application Laid-Open No. 9-202123 discloses a technique, but is a technique for a rear-wheel two-axle vehicle, and does not relate to the subject of the present application.

[0006]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned problems of the prior art, and aims to improve the safety and workability of a ladder truck or a crane truck, and to improve the reliability of a mounted object. The aim is to provide a vehicle leveling device that can improve the vehicle level.

[0007]

The vehicle leveling device according to the present invention is used, for example, when a working vehicle, a truck or the like holds the vehicle horizontally for work, loading, or the like. In a vehicle leveling device for holding a vehicle having a hydraulic suspension device horizontally, a height sensor is mounted between a frame and front and rear axles, and an inclinometer is mounted on the frame. An electric circuit is connected to a control device that controls the device, and the control device is configured to control expansion and contraction of a hydraulic cylinder that suspends each wheel based on signals from the height sensor and the inclinometer. In practicing the present invention, the suspension device may be an air suspension device or an active suspension device.

According to the present invention having such a configuration, the expansion and contraction of the hydraulic cylinder is controlled before the outrigger is set, so that the frame and various objects mounted thereon are kept horizontal. . Therefore, it is possible for the vehicle to travel on an inclined surface while working with the upper object mounted on the frame. Also, since the frame and the various objects mounted on it are kept horizontal, the limit tilt angle of the ladder and boom does not differ depending on the turning direction of the object, etc. There is a possibility of causing a problem

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a rear view of the crane truck. A rear portion of a frame 2 of the crane truck 1 is supported by a left hydraulic cylinder 4 and a right hydraulic cylinder 5 of a rear shaft 3. The road surface 21 is inclined by an angle α with respect to the horizontal plane, while the left hydraulic cylinder 4 extends and the right hydraulic cylinder 5 contracts so that the frame becomes substantially horizontal. The height sensor 31 and the inclinometer 29 are attached to the frame 2 and connected to the control device 35 by electric circuits. Here, reference numeral 7 is a gyro ring, 8 is an outrigger, 9 is a crane body, 11 is a boom, 13 is a pulley, 15 is a hook, 17 is a lifting object,
Numeral 19 indicates a tire.

FIG. 2 shows a hydraulic and electric circuit of one wheel of the hydraulic suspension system for a crane truck shown in FIG. 1. A hydraulic cylinder 4 (at least four suspension hydraulic cylinders are required for the whole vehicle, but the whole is also denoted by reference numeral 4). Is a suspension lock valve 2 through hydraulic circuits a and b.
The signal pressure connection port of the suspension lock valve 25 is connected to an oil pump (not shown) via a hydraulic circuit f, a solenoid valve 26, and hydraulic circuits g and h.

The hydraulic cylinder 4 is connected to an oil tank (not shown) through hydraulic circuits a and c, a solenoid valve 28 for drain, and a hydraulic circuit k.
It is connected to the oil pump via a charging solenoid valve 27.

Further, the suspension lock valve 25 is connected to the accumulator 33 and to the oil tank via hydraulic circuits j and k.

The controller 35 is connected to the solenoid valves 26, 27 and 28, the inclinometer 29 mounted on the frame 2, the vehicle horizontal switch 30, and the height sensor 31 by electric circuits.

The operation will now be described with reference to FIGS. 3 and 6 which show only a part of the crane body of FIG. In operation, first, it is determined whether or not the vehicle is stopped, for example, by turning on / off the vehicle horizontal switch 30 (step S1). If step S1 is NO, the loop is repeated. On the other hand, if step S1 is YES, a signal from each height sensor 31 and a signal from the inclinometer 29 are input (step S2). In this case, the vehicle is generally inclined as shown in FIG. Next, the opening and closing of each solenoid valve for leveling the frame 2 of the vehicle is determined based on a predetermined standard (step S3), and the hydraulic cylinders 4 are expanded and contracted to adjust the level of the frame (step S4, vehicle). Is horizontal as shown in FIG. 5).

When the hydraulic cylinder 4 is extended, the suspension lock valve 25 is locked by the electromagnetic valve 26 to close the space between the accumulator 33 and the hydraulic cylinder 4 and the electromagnetic valve 27 is closed.
Is opened and oil is supplied from the oil pump to the hydraulic cylinder 4 via the hydraulic circuits h, c, and a. When the hydraulic cylinder 4 is contracted, the solenoid valve 28 is opened and the oil is returned to the oil tank via the hydraulic circuits a, c, and k.

Next, it is determined whether or not the inclination of the frame is within a predetermined inclination angle (step S).
5). In addition, as shown in FIG. 6, the operation of extending the outrigger may be performed here.) If step S5 is NO, the process returns to step S2. If step S5 is YES, it is determined whether or not the upper object is horizontal (step S6). If the upper object is not horizontal (NO in step S6), the gyro ring between the frame 2 and the upper object is corrected (step S6).
7), and return to step S6. If step S6 is YES, the control ends.

While the vehicle is running, the vehicle horizontal switch 30
Is turned off, the solenoid valve 26 is turned off, the hydraulic cylinder 4 communicates with the accumulator 33, and the control device controls the hydraulic cylinder 4 to operate as a hydraulic suspension.

FIG. 7 shows a case where the suspension device is an air suspension device. Air springs 4a to 4d are respectively attached to the wheels (not shown),
Height sensors 31a to 31d are provided at the respective wheel positions. The suspension lock switch 40 connected to the control device 35 activates the solenoid valves 42 of the respective wheels to perform suspension lock, and controls the solenoid valves 41 of the respective wheels to control the suspension. The wheel air springs 4a to 4d are expanded and contracted. Here, the operation of adjusting the level of the vehicle is the same as that of the hydraulic suspension. In the case of trucks and buses, an air suspension is used in many cases, so that the above configuration may be adopted. Reference numeral 43 indicates an exhaust port of the solenoid valve 41.

The present invention is configured as described above and has the following excellent effects. (1) Since the level of the vehicle can be secured when the outrigger is extended, the correction by the gyro is unnecessary or can be performed in a short time. (2) Since the sprung center of gravity of the vehicle coincides with the mounting center of the upper object, there is no change in stability depending on the turning direction, and the vehicle is safe. (3) Compared with the conventional gyro-only correction, the correction allowance is extremely large, work can be performed in any work place, and it is extremely effective for fire ladder trucks. (4) Since it can be applied to an air suspension or the like, the range of application is large.

[Brief description of the drawings]

FIG. 1 is a rear view of a vehicle showing an embodiment of the present invention.

FIG. 2 is a hydraulic suspension circuit diagram of FIG.

FIG. 3 is a flowchart of the control in FIG. 2;

FIG. 4 is a rear view showing a state where the vehicle is stopped on a slope.

FIG. 5 is a view showing the state of step S4 in the flowchart of FIG. 3;

FIG. 6 is a diagram showing a state in which an outrigger is extended in FIG. 5;

FIG. 7 is a circuit diagram of an air suspension according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 2 ... Frame 3 ... Axle 4, 5 ... Hydraulic cylinder 7 ... Gyro ring 8 ... Outrigger 9 ... Crane main body 25 ... Susp lock valve 26,27,28 ... Electromagnetic valve 29 ... Inclinometer 31 ... Height sensor 35 ... Control device

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Claims (1)

[Claims] 1. A vehicle leveling device for holding a vehicle having a hydraulic suspension device horizontally, wherein a height sensor is mounted between a frame and front and rear axles, an inclinometer is mounted on the frame, and the height sensor and the tilt sensor are provided. The meter is connected by an electric circuit to a control device that controls a suspension device of the vehicle, and the control device is configured to control expansion and contraction of a hydraulic cylinder that suspends each wheel based on signals from the height sensor and the inclinometer. A vehicle leveling device.