JPH038716Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a brake cylinder operation circuit that operates actuators such as hydraulic cylinders in brake operation of winch drums, etc., and relates to hydraulic deck cranes and hydraulic deck machinery. It is used for etc.

(Prior art) The conventional technology will be described with reference to FIG. This device is a hydraulic circuit that releases the brake when the actuator 2 is in operation, such as in a winch drum, and operates the brake when the actuator 2 is not in operation. In the hydraulic circuit, the oil discharged from the hydraulic pump 1 enters the actuator 2 via the switching valve 4, operates it, and then returns to the tank 15 via the switching valve 4.
As shown in the figure, in a hydraulic circuit where the brake cylinder 3 is acting as a brake when the switching valve 4 is in the neutral position, as an example of releasing the brake, for example, when switching the switching valve 4 to the left position, the oil discharged from the hydraulic pump 1 is It enters the actuator 2 via a conduit 6. At this time, the oil pressure that has increased to the load pressure in the pipe line 6 passes from the branch point to the pipe line 8 and is further communicated from the branch point to the pilot line 10, switching the switching valve 5 in the valve position shown in FIG. 4 to the left position. As a result, the cylinder drive hydraulic pressure supply port P shown in FIG.
1 and the cylinder connecting hole A communicate with the pipe line 12, so that the hydraulic pilot pressure oil for driving the hydraulic cylinder acts on the brake cylinder 3, and the brake is released. Further, when the switching valve 4 is switched to the right position in the opposite direction to the above, the oil pressure of the system is communicated with the pilot line 11 through the pipes 7 and 9, and the switching valve 5, which is in the valve position shown in FIG. 4, is switched to the right position. As mentioned above, from the pipes 7 and 8 to the cylinder drive hydraulic pressure supply port P2 in Fig. 4.
The cylinder connecting hole A is connected to the cylinder connecting hole A, and communicates with the pipe line 12, so that hydraulic pressure acts on the brake cylinder 3, and the brake is released.

The brake cylinder 3 is structured so that the brake is activated when no hydraulic pressure is applied, and the brake is released when hydraulic pressure is applied. That is, a tension spring is activated in the brake hydraulic cylinder 3, and when the hydraulic pressure is 0 or low, the spring force prevails and the brake is automatically activated. Therefore, when the hydraulic pilot pressure is obtained from the system as in this example, depending on the load, the hydraulic pilot pressure may become lower than the spring force, and there is a concern that the braking action may become unstable under the influence of this.

(Problems to be Solved by the Invention) Conventionally, a pilot hydraulic power source for operating a hydraulic cylinder, which is an actuator, is obtained from this system or another system. Therefore, if the pilot hydraulic power source is removed from a system where the pressure is unstable, the operating pressure to the brake hydraulic cylinder will be affected, causing problems such as the brake itself operating or opening.

Next, in order to prevent the effects of the unstable system mentioned above, some systems take the pilot oil pressure source from another stable system and operate it using a solenoid valve, but the equipment becomes complicated because the brake timing must be matched. There are drawbacks.

In addition, there are examples in which countermeasures have been taken by providing check valves, relief valves, etc. in the return line that utilize the cracking pressure of the valve in the hydraulic circuit, but this has the disadvantage of causing circuit loss.

(Means for Solving the Problems) In order to solve these problems, the present invention extracts the pilot hydraulic pressure directly from the system, or extracts the pilot hydraulic pressure through a shuttle valve and switches the hydraulic pilot operation direction switching valve 5. By applying this function, the pilot hydraulic pressure for driving the brake hydraulic cylinder can be derived from another stable system, and a reliable and stable braking action can be performed with a relatively simple device.

As shown in Fig. 2, the hydraulic pilot operation direction switching valve 5 has one cylinder drive pilot oil pressure supply hole P, and when the valve is neutral, the cylinder connection hole A and the tank connection hole T are connected, and the pilot oil pressure drops to the drain pressure. do. Next, in the left and right positions, the cylinder drive pilot oil pressure supply hole P and the cylinder connection hole A are connected by the pilot signal from the system, and the tank connection hole T is closed, so that ON-OFF operation can be performed.

Two operations can be automatically performed for one pilot oil pressure supply port P by three types of signals to the switching valve.

(Example) Referring to FIG. 1, an example of the present invention will be described in detail. Reference numeral 5 denotes a hydraulic pilot operating direction switching valve, which is a 3-position, 3-port switching valve, and has a structure as shown in FIG. As shown in Fig. 2, the cylinder drive pilot oil pressure supply hole P is in one place, and when the valve is neutral, the cylinder connection port A that communicates with the cylinder and the tank connection port T that communicates with the tank are connected, and the pilot pressure oil is supplied up to the drain pressure. descend. Next, in the left and right positions, the cylinder drive pilot oil pressure supply hole P and cylinder connection hole A communicate with each other due to the pilot signal from the system, and the tank connection port T becomes blocked.
ON-OFF operation is performed. Two operations can be performed for one pilot oil pressure supply hole using three switching signals.

(Operation) FIG. 1 shows a state in which the switching valves 4 and 5 are in neutral, so the actuator is inoperative and the brake is in operation. That is, the oil pressure of the hydraulic pump 1 passes through the switching valve 4 and the oil returns to the tank 15. On the other hand, since the hydraulic pilot operating direction switching valve 5 remains neutral, the hydraulic pressure connected to the cylinder drive pilot hydraulic pressure supply hole P is cut off and the brake is in an operating state.

When the switching valve 4 is switched to the left (right) position, it acts on the hydraulic switching valve 5 from the pilot branch point through the pilot lines 10, 11 as in the conventional circuit, and the valve symbol shown in FIG. ) position, the hydraulic pilot for driving the hydraulic cylinder communicates with the pipes 14 to 12, acts on the brake cylinder 3, and the brake is released.

Next, when the switching valve 4 is returned to the neutral position, the pressure decreases because it is connected to the tank 15. Similarly, the pressure of the pilot lines 10 and 11 also decreases, and the hydraulic switching valve 5
is returned to the neutral position as shown in FIG. 2 by the valve spring. Therefore, the brake cylinder operating pilot pressure oil returns from the pipe 12 to the tank 15 via the hydraulic pressure switching valve 5 and the pipe 13.
The brake cylinder 3 is returned to the state before the valve operation by the brake tension spring, and the brake is applied again.

(Effects of the invention) As is clear from the above explanation, according to the invention,
The hydraulic pilot operating direction switching valve 5 can automatically obtain pilot hydraulic pressure directly from the system via the pilot lines 10 and 11, and at the same time, the hydraulic brake operating hydraulic pressure source is a stable hydraulic pilot source for other systems. This has the remarkable effect of ensuring reliable braking action and eliminating braking instability.

[Brief explanation of the drawing]

FIG. 1 is a hydraulic circuit diagram according to the present invention, FIG. 2 is a diagram of a hydraulic valve according to the present invention, FIG. 3 is a conventional hydraulic circuit diagram, and FIG. 4 is a diagram of a conventional hydraulic pilot operation direction switching valve. 1... Hydraulic pump, 2... Actuator, 3
...Brake cylinder, 4...Switching valve, 5...Hydraulic pilot operation direction switching valve, 6-9...Pipe line,
10, 11...Pilot line, 12-14...
...Pipeline, 15...Tank, 16...Relief valve,
P...Cylinder drive pilot oil pressure supply port, A...
...Cylinder connection port, T...Tank connection port, P1,
P2...Cylinder drive hydraulic pressure supply port, A...Tank connection port.

Claims (1)

[Scope of utility model registration request] In the brake cylinder operating circuit, there are three positions (neutral, left, and right) to control the opening and closing of the pipe leading to the brake cylinder, and three holes: cylinder connection hole A, tank connection hole T, and cylinder drive pilot oil pressure supply hole P. In the neutral position, the cylinder connection hole A and the tank connection hole T are connected, and the cylinder drive pilot hydraulic pressure supply hole P is closed, and in the left and right positions, the cylinder connection hole A and the tank connection hole T are connected. A hydraulic pilot operation direction switching valve that connects the cylinder drive pilot oil pressure supply hole P to the cylinder drive pilot oil pressure supply hole P, and connects the cylinder connection hole A and the tank connection hole T to the closed position, and connects the cylinder drive pilot oil pressure supply hole P directly to the system. 1. A brake cylinder operation circuit comprising: a pilot hydraulic pressure source that is connected to a cylinder; a pipe line connecting a cylinder and a cylinder connection hole A; and a line connecting a tank and a tank connection hole T.