JPH0536721Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a suspension device for a crane vehicle such as an all-terrain crane vehicle.

[Conventional technology]

In conventional crane trucks, such as all-terrain crane trucks, various types of suspension springs are generally installed between the front and rear axles and the chassis frame to ensure ride comfort and running performance when traveling on the road. Also, during on-tire work, that is, when lifting and unloading cargo without using outriggers to stabilize the car body during crane work, the instability of the car body due to elastic deformation of the suspension spring can be prevented. In order to prevent this as much as possible, a hydraulic cylinder device is provided to fix the front and rear axles and the chassis frame. During normal road running, the hydraulic cylinder device is allowed to expand and contract freely, or functions as a shock absorber by communicating the chambers on both sides of the piston in the cylinder through an orifice. On the other hand, crane trucks have a heavy crane and its operating room mounted on the undercarriage frame, so the center of gravity is generally high, making it difficult to turn the steering wheel suddenly when turning sharp curves with a small radius of curvature or when driving at high speeds. There is an inherent tendency to fall easily.

[Problem that the invention attempts to solve]

The present invention utilizes a hydraulic cylinder device normally installed in all-terrain cranes to fix the axle and chassis frame during on-tire crane work, and improves the overturning performance while traveling. The purpose is to

[Means for solving problems]

The present invention was devised to achieve the above object, and includes hydraulic cylinders interposed between the chassis frame and the front and rear axles on both sides of the vehicle body.
A solenoid valve that connects or shuts off oil chambers on both sides of each piston of each hydraulic cylinder, an extension switch that is attached to each of the above hydraulic cylinders and that is closed when the respective piston shaft extends to a set position relative to the cylinder; A retraction switch attached to the hydraulic cylinder and closed when each piston shaft retracts to a set position relative to the cylinder, a front-rear extension switch on one side of the on-board power supply and vehicle body, and a front-rear contraction switch on the other side of the vehicle body. A first connecting the switch and at least the front and rear solenoid valves on the other side in series.
a second electrical circuit that connects in series the electrical circuit and onboard power source, a front and rear retraction switch on one side of the vehicle body, a front and rear extension switch on the other side of the vehicle body, and a front and rear solenoid valve on at least one side; When the vehicle body is tilted to one side or the other side and the second circuit or the first circuit is closed, at least the front and rear solenoid valves on the contracted hydraulic cylinder side are shut off. The gist of the present invention is a suspension device for a mobile crane, characterized in that it is equipped with a circuit device for inhibiting further contraction of the contracted hydraulic cylinder.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the figure, reference numeral 10 is a conceptually shown chassis frame of a crane truck, 12 is a front axle, also conceptually shown, 14 is a rear axle, and 16 is an engine. Between the chassis frame 10 and the front axle 12,
A pair of left and right hydraulic cylinders 18LF and 18RF are interposed, and each hydraulic cylinder includes a cylinder 20 whose upper end is pivotally connected to the chassis frame 10, and a piston 22 slidably fitted into the cylinder. The lower end of the shaft 22' is pivotally connected to the front axle 12. In addition, the chassis frame 10 and the rear axle 1
4, there is a pair of left and right hydraulic cylinders 18LR.
and 18RR are interposed, and these hydraulic cylinders include a cylinder 24 whose upper end is pivotally connected to the chassis frame 10, and a piston 26 slidably fitted into the cylinder, with the lower end of the piston shaft 26' being at the rear. It is pivotally mounted on an axle 14. Each hydraulic cylinder 1
8LF, 18LR, 18RF, and 18RR piston shafts 22' and 26' are fixed with stroke indicators 30 each having a hook-shaped engager 28 at the tip, while on the cylinders 20 and 24,
Retraction switches 32LF (front left side of the vehicle body) and 32LR (rear left side of the vehicle body) are engaged with the engager 28 of the stroke indicator 30 and closed when the piston shaft enters the cylinder to a preset retracted position. , 32RF (front right side of the vehicle body) and 32RR (rear right side of the vehicle body) are provided, respectively, and when the piston shaft extends to a preset extended position, it engages with the stroke indicator 30 and is closed. Switch 34LF (front left side of vehicle body), 34LR
(rear left side of the vehicle body), 34RF (front right side of the vehicle body), and 3
4RR (rear right side of the vehicle body) is installed. And the contraction switches 32LF and 32LR on the front and rear left side of the vehicle body, and the extension switch 34RR on the front and rear right side of the vehicle body.
and 34RF are connected in series to the on-vehicle power supply 36, and the solenoid valves 38 for controlling each hydraulic cylinder.
Connected to LF, 38LR, 38RR and 38RF excitation coils. On the other hand, the extension switches 34LF and 34LR on the left side of the vehicle body and the contraction switches 32RR and 32RF on the right side of the vehicle body are connected to the vehicle power supply 3.
6 are connected in series to control solenoid valves 38LF, 38LR, 38RF and 38 for each hydraulic cylinder.
Connected to the RR excitation coil.

In the above configuration, each control solenoid valve is deenergized in the illustrated state, and while the vehicle is running, the hydraulic chambers on both sides of the piston of each hydraulic cylinder 18LF, 18LR, 18RF, and 18RR are communicated with each other by the solenoid valve. Therefore, when the vehicle body shakes or vibrates while driving, the hydraulic oil in each hydraulic cylinder reciprocates between the hydraulic chambers on both sides of the piston through the hydraulic oil passages, including the oil passages in the solenoid valves, and The hydraulic cylinder is acting as a shock absorber. Next, when the vehicle body leans to one side, for example, to the left side, due to a sudden turn while driving, the front and rear hydraulic cylinders 18LF and 18LR on the left side of the vehicle body simultaneously contract, and the front and rear hydraulic cylinders 18RF and 18RR on the right side of the vehicle body simultaneously expand. When the amount of contraction and expansion of each cylinder reaches a predetermined setting value, the engager 28 of the stroke indicator 30 activates the left contraction switches 32LF and 32LR and the right expansion switches 34RR and 34RF, which are connected in series. As each solenoid valve 38LF and 38 are closed, electric circuit A is completed.
LR, 38RR and 38RF are energized at the same time,
Each hydraulic cylinder 18LF, 18LR, 18RR
Communication between both chambers of the piston of 18RF and 18RF is completely cut off. Since the flow of hydraulic oil from the hydraulic chamber above the piston of each hydraulic cylinder is prohibited by the check valve 40, each hydraulic cylinder (especially the tilted left hydraulic cylinder is important) cannot contract. , it is clear that as a result of this, an increase in the lean of the vehicle to the left is effectively prevented, which may improve the overturning performance. Further, even if the vehicle body leans to the right while turning, the electric circuit B is completed in the same way and the same effect is achieved. Next, when the vehicle starts driving straight after completing a turn, contraction of each hydraulic cylinder is prohibited, but extension is not prohibited, so the hydraulic cylinder on the inclined side immediately expands, and the stroke indicator 30 and contraction Since the engagement with the switch is released, all the electromagnetic valves are deenergized and the hydraulic cylinder automatically returns to its initial state, and thereafter operates as a shock absorber again. Furthermore, each of the above hydraulic cylinders 18LF,
Regarding all of 18RF, 18LR and 18RR,
Electromagnetic valves similar to those shown in the diagram are installed in the pipes communicating with the hydraulic chambers on both sides of each piston, and
The check valve 40 may be omitted, and all solenoid valves may be energized to lock and fix the hydraulic cylinder in both contraction and extension when the vehicle body is tilted to either side as described above. . According to this modification, the extension of the hydraulic cylinder on the opposite side to the inclined side is simultaneously prohibited, so that the overturning performance can be further improved. However, in this case, it will be a problem if the hydraulic cylinder remains locked so that it cannot expand or contract even after the vehicle has finished turning, so it is necessary to provide some kind of auxiliary unlocking means, such as a solenoid valve. A switch that automatically opens when a steering system member such as a steering wheel is near the neutral position can be installed in the energizing circuit of 38LF to 38RR. Furthermore, as can be easily understood from the above explanation, some changes have been made to the illustrated embodiment, and by completing the circuit A, only the solenoid valves 38LF and 38LR, that is, the contraction side solenoid valves, are energized, and the circuit B is activated. With the completion of the solenoid valve 38
Even if RF and 38RR (also on the contraction side only) are energized, substantially the same effect of improving the falling performance can be achieved. In the figure, reference numeral 42 is a pressure oil pump driven by the engine 16, 44 is an oil rizal, and 46 is a switching valve provided for a purpose not directly related to the present invention.

The configuration of the present invention is extremely advantageous because it can reliably detect the inclination of the vehicle body and improve the overturning performance by simply providing eight switches that are simple, inexpensive, and have excellent durability. Conventionally, inclinometers and accelerometers that detect lateral acceleration have been used for this type of purpose, but they are generally fairly expensive, delicate, and prone to failure, and are sensitive to vibrations of the vehicle body while driving. However, there are problems such as a tendency to cause malfunctions, and it cannot be said to be suitable for use in work vehicles such as crane trucks.

[Effect of idea]

As described above, the crane vehicle suspension device according to the present invention includes hydraulic cylinders interposed between the chassis frame and the front and rear axles on both sides of the vehicle body, and oil chambers on both sides of the respective pistons of each hydraulic cylinder. an extension switch that is attached to each of the hydraulic cylinders and closes when the respective piston shaft extends to a set position relative to the cylinder; a retraction switch that closes when retracted to a set position, a front and rear extension switch on one side of the vehicle power supply and the vehicle body, a front and rear contraction switch on the other side of the vehicle body, and a front and rear solenoid valve on at least the other side. A first electric circuit and an on-vehicle power source connected in series, a front and rear contraction switch on one side of the vehicle body, a front and rear extension switch on the other side of the vehicle body, and a front and rear solenoid valve on at least one side are connected in series. When the vehicle body is tilted to one side or the other side and the second circuit or the first circuit is closed, at least the contracted hydraulic cylinder side To improve the overturning performance of a crane truck with a simple and inexpensive configuration, characterized by comprising a circuit device that blocks the front and rear solenoid valves to prevent further contraction of the contracted hydraulic cylinder. It is useful because it allows

[Brief explanation of the drawing]

The accompanying drawing is a schematic diagram showing an embodiment of the present invention. 10... Chassis frame, 12... Front axle, 14
...Rear axle, 16...Engine, 18LF, 18
LR, 18RF and 18RR...hydraulic cylinder, 3
0...Stroke indicator, 32LF, 32
LR, 32RF and 32RR...Retraction switch, 3
4LF, 34LR, 34RF and 34RR... Extension switch, 36... Power supply, 38LF, 38LR, 38
RF and 38RR... Solenoid valve, 40... Check valve, 4
2... Pressure oil pump, 44... Oil reservoir.

Claims (1)

[Scope of utility model registration request] Hydraulic cylinders interposed between the undercarriage frame and the front and rear axles on both sides of the vehicle body, electromagnetic valves that communicate or cut off the oil chambers on both sides of the respective pistons of each hydraulic cylinder, and each hydraulic cylinder attached to each of the above hydraulic cylinders. an extension switch that is closed when the piston shaft of the cylinder extends to a set position relative to the cylinder; a retraction switch attached to each hydraulic cylinder that is closed when the respective piston shaft retracts relative to the cylinder to a set position; and an on-board power source. a first electrical circuit that connects in series a front and rear extension switch on one side of the vehicle body, a front and rear contraction switch on the other side of the vehicle body, and a front and rear solenoid valve on at least the other side; A second electric circuit connects in series a front and rear contraction switch on one side of the vehicle body, a front and rear extension switch on the other side of the vehicle body, and a front and rear solenoid valve on at least one side. When the vehicle body is tilted to the other side and the second circuit or the first circuit is closed, at least the front and rear solenoid valves on the side of the contracted hydraulic cylinder are shut off to prevent further contraction of the contracted hydraulic cylinder. A suspension device for a crane truck, characterized in that it is equipped with a circuit device that prohibits the prohibition.