JPS586778Y2 - steering device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a steering device in which braking mechanisms for independently controlling left and right traveling devices are respectively operated by hydraulic cylinders.

In conventional braking mechanisms operated by hydraulic cylinders, the maximum braking force is always constant regardless of the traveling speed of the aircraft, and the braking effect due to the degree of operation of the operating tool is approximately constant. When steering the aircraft while traveling at high speed, it will make a sharp turn, and due to the extremely strong centrifugal force (inversely proportional to the turning radius r and proportional to the square of the traveling speed V) that occurs with this sharp turn, This may cause the aircraft to overturn, posing a danger to workers, or even if the aircraft does not overturn, the steering operation may become unstable.

The present invention was developed in view of the above-mentioned circumstances and aims to eliminate the above-mentioned drawbacks by improving the hydraulic system.

Hereinafter, embodiments of the present invention will be described with reference to illustrative drawings.

Figure 1 shows the hydraulic circuit showing the steering operation system.
, 1, respectively, and a braking mechanism 3, which applies braking force to each of the left and right traveling devices 1, 1.
The steering device 4.4 is configured to be controlled by the operation of hydraulic cylinders 5, 5.

The hydraulic cylinders 5, 5 receive pressure oil from the hydraulic pump 6,
By operating the three-position direct switching valve 7 interposed in the oil supply path,
It is configured so that it can be switched between a turning state in which refueling is selectively applied to either side, and a straight traveling state in which refueling is blocked.

Further, each of the hydraulic cylinders 5 is provided with a relief valve 8 as a valve mechanism communicating with the drain oil path a at an intermediate portion of the operating stroke.

The spring 10 for setting the relief pressure of the relief 9f8 is connected via a wire 12 to a speed change lever 11 as a traveling speed change mechanism provided in a pilot seat (not shown), and the speed change lever 11 is moved from a low speed side to a high speed side. The structure is such that the pressing force of the spring 10 decreases as the spring moves toward the opposite direction.

According to the above configuration, the three-position direct switching valve 7 is switched to supply pressure oil from the hydraulic pump 6 to one of the hydraulic cylinders 5, and as the hydraulic cylinder 5 is extended, one of the clutches 2 is disengaged, and the braking is continued. In this case, the maximum working pressure of the hydraulic cylinder 5, in other words, the braking mechanism 3 is activated.
The braking force of IJ is determined by the operating pressure of IJ-F 8.

Since the pressing force of the spring 10 that sets the operating pressure of the IJ IJ valve 8 is reduced as the traveling speed increases, the braking force of the brake mechanism 3 becomes smaller when traveling at high speed, and the turning characteristics are deteriorated. This will reduce sharp turns and avoid sharp turns.

Note that when the traveling speed is extremely high, the operating pressure of the IJ valve 8 is almost zero, so in this case, the hydraulic cylinder 5 is extended only halfway through its stroke, and only the clutch 2 is disengaged to perform braking. Steering is performed with the mechanism 3 not operating.

As shown in FIG. 3, the valve mechanism 8 provided in the drain oil path a is located at a position A for blocking cylinder oil drain, at a position A for providing resistance to the flow of cylinder oil drain, and at a position A for providing resistance to the flow of cylinder oil drain. It consists of a switching valve that can be switched to three positions, C and C, which allow free flow, and this valve mechanism 8 and the gear shift lever 11
With this, the braking mechanism 3 is operated in conjunction with the traveling speed change.
It may be configured to operate in stages.

As shown in the embodiments above, the present invention is provided with a valve mechanism that changes the maximum working pressure of the hydraulic cylinder, and also links this valve mechanism with the traveling transmission mechanism, so that the maximum working pressure of the hydraulic cylinder increases as the traveling speed increases. Since it is characterized in that the hydraulic pressure is reduced, it is possible to perform a desired steering operation that matches the traveling speed of the aircraft.

In other words, even if the aircraft is steered while traveling at high speed, the braking force decreases, so even if the traveling speed V is high, the turning radius r becomes large, so the centrifugal force generated on the aircraft does not increase, and it is difficult to make sharp turns. This prevents the machine from falling over, ensuring worker safety, and making it easier to steer the machine, thereby improving work efficiency.

[Brief explanation of drawings]

The drawings illustrate an embodiment of the steering device according to the present invention, FIG. 1 is a hydraulic circuit diagram showing the steering control system, FIG. 2 is an enlarged sectional view showing the main parts, and FIG. 3 is another embodiment. It is a schematic explanatory diagram showing an example. 1... Traveling device, 3... Braking mechanism, 5
... Hydraulic cylinder, 8 ... Valve mechanism, 1
1... Travel transmission mechanism.

Claims (1)

[Claims for Utility Model Registration] ■ A steering device configured to operate brake mechanisms 3, 3 for independently braking the left and right traveling devices 1, 1, respectively, with hydraulic cylinders 5, 5, respectively, wherein the hydraulic cylinders A valve mechanism 8, 8 is provided to change the maximum operating oil pressure of the hydraulic cylinders 5, 5, and the valve mechanism 8, 8 and the traveling transmission mechanism 11 are linked to change the maximum operating pressure of the hydraulic cylinders 5, 5 as the traveling speed increases. A steering device characterized in that it is configured to reduce hydraulic pressure. (2) The steering device according to claim (2), wherein the valve mechanism 8 is an IJ-F valve connected to the hydraulic cylinder 5 in the middle of its stroke.