JPH032723Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a shut-off control circuit that controls the flow of pressure fluid between an accumulator storing pressure oil and an actuator operated by the accumulator.

Regarding flow rate control between the accumulator and actuator 2, conventionally, as shown in Fig. 1, a solenoid valve 3 is installed between the accumulator and actuator 2.
and the check valve 4 were connected in series. The control in which the pressure oil accumulated in the accumulator 1 is applied to the actuator 2 by switching the solenoid valve 3 as described above has the following drawbacks.

1 The solenoid valve is a spool-type switching valve, so the shock when switching is large, and since it is a spool-type, it is impossible to reduce leakage to zero, and the pressure oil filled in the accumulator escapes to the tank via the solenoid switching valve. Therefore, the accumulator could not be maintained at high pressure for a long time.

2. Since a spool-type switching valve always has a spool and a valve box wrapped together, a certain amount of time is required for switching, and instantaneous switching is impossible.

3 Spool-type switching valves are rare in large capacity, and even when they are available, they are expensive.

4. Since the pressure oil acting from the accumulator to the actuator is at high pressure, the actuator only moves at a high speed, which is not suitable when it is desired to change the moving speed of the actuator.

The present invention eliminates such drawbacks, and its purpose is to provide a shut-off control circuit that eliminates leakage from the accumulator, has less shock, shortens switching time, has a large capacity, and is also capable of controlling actuator speed. There is a particular thing.

In order to accomplish the above-mentioned purpose, the present applicant has developed a shut-off control circuit that controls the flow of pressure oil between an accumulator storing pressure oil supplied from a hydraulic source and an actuator operated by the pressure oil from the accumulator. an accumulator that introduces pressure oil from a hydraulic source to a pressure set in a relief valve via a first electromagnetic switching valve and a check valve; and an accumulator that is located between the hydraulic source and the actuator, A second electromagnetic switching valve is provided in parallel with the valve and supplies pressure oil from the hydraulic source to the actuator and discharges the pressure oil in the actuator to the oil tank. A logic valve is provided in a circuit connecting between the two, and a check valve and a throttle valve with a small opening are installed in series, branching from the circuit connecting the inlet of the accumulator and the logic valve, and connecting the pilot chamber of the logic valve. a first pilot circuit communicating with the first pilot circuit, and a second pilot circuit branching from the circuit connecting the logic valve outlet and the actuator and communicating between the two throttle valves in the first pilot circuit via a pilot check valve. and a third electromagnetic switching valve that is located between the hydraulic pressure source and the pilot check valve and controls the opening and closing of the third pilot circuit in the pilot check valve, and The shut-off control circuit is characterized in that it opens and closes the logic valve by controlling the pressure oil from the first pilot circuit that operates, and also controls the speed of the actuator in cooperation with the hydraulic pressure source.

Further, the second pilot circuit is a shut-off control circuit characterized in that the second pilot circuit branches from between two throttle valves in the first pilot circuit and returns to the tank via a pilot check valve. .

In such a control circuit, the pressure oil accumulated in the accumulator quickly flows out to the actuator without a shock due to the logic valve, and unlike the spool-type switching valve, there is no leakage of pressure oil, so the pressure oil accumulates in the accumulator. The amount of pressure oil leaking from the pump can be completely eliminated, the accumulator can be kept at high pressure for a long time, a large amount of pressure oil can flow, and the speed of the actuator can also be controlled.

Next, one embodiment of the present invention will be described with reference to FIG. 2. Reference numeral 11 denotes an accumulator connected to an electromagnetic switching valve 13 via a check valve 12 and connected to a discharge port of a pump 15 driven by an electric motor 14. .

16 is a relief valve of the pump. The accumulator 11 is connected to the B port which is the inlet of the logic valve 17, and a first pilot circuit 26 is branched from a circuit connecting the accumulator 11 and the inlet B port of the logic valve 17. It is connected to chamber 17a. The first pilot circuit 26 is provided with a check valve 18 and throttle valves 19 and 20 in series, each having an opening narrowed to a small diameter of about 1 mmφ, to smoothly operate the logic valve 17, which will be described later. I try to make it work efficiently. The A port, which is the outlet of the logic valve 17, is connected to the actuator 21.
A circuit 28 is connected to the pump 15, and the circuit 28 and the pump 15 are connected via an electromagnetic switching valve 22. A second pilot circuit 27 having a pilot check valve 25 branches off from the circuit 28 connecting the logic valve 17 and the actuator 21, and connects the two throttle valves 1 in the first pilot circuit.
9 and 20. The pilot check valve 25 includes a pilot circuit 29 for controlling the opening and closing of the valve 25 by switching the electromagnetic switching valve 24.
is provided.

The structure is as described above, and its operation will be explained next. First, the electromagnetic switching valve 22 is set to the left position of the non-excited state shown in the figure, and the electromagnetic switching valve 13 is set to the left position of the energized state. When the electromagnetic switching valve 24 is in the lower position shown in the figure, the accumulator 11 is filled with pressure oil by the pump 15 until the pressure reaches the pressure set in the relief valve 16. When the filling of the accumulator 11 is completed, the electromagnetic switching valve 13 is set to the right position, the pressure oil circuit from the pump 15 is cut off, and the electromagnetic switching valve 13 is turned off.
4 is in the upper position and the electromagnetic switching valve 22 is in the right position, the pressure oil discharged by the pump 15 acts on the actuator 21 with a moving pressure lower than the hydraulic pressure set in the relief valve 16, and the actuator 21 moves to the right in the figure. At the same time, the pilot check valve 25, which had been closed until now, becomes open because pressure oil from the pump 15 acts on the third pilot circuit 29 via the electromagnetic switching valve 24, and the second pilot circuit 27 opens and the third pilot circuit 29 opens. One pilot circuit 26 communicates with a circuit 28 connecting the logic valve 17 and the actuator 21.

Therefore, a part of the pressure oil accumulated in the actuator 11 is transferred to the first pilot circuit 26 and then to the second pilot circuit 26.
The pressure oil from the first pilot circuit 26 does not act on the vent chamber 17a of the logic valve 17; The logic valve 17 is opened and the pressure oil from the accumulator 11 pushes up the poppet of the logic valve 17 and acts on the actuator 21 via the circuit 28.

At this time, while the filling pressure from the accumulator 11 is high, the actuator 21 is controlled by the high pressure hydraulic oil from the accumulator 11 and moves at high speed, but as the filling pressure of the accumulator 11 gradually weakens, the actuator 21 moves at high speed. The moving speed slows down, and when it reaches a certain position, a switching signal (not shown) causes the electromagnetic switching valve 24 to return to the lower position, and the pilot check valve 25 closes.
Therefore, the pressure oil passing through the first pilot circuit 26 is
As a result, the logic valve 17 closes, and the pressure oil from the accumulator 11 stops flowing to the circuit 28, and the circuit 28 acts on the pilot chamber 17a of the logic valve 17.
Only a small amount of hydraulic oil flows due to actuator 2.
1 is moved by the pressure oil of the pump 15.

Therefore, the actuator 21 can be controlled from low speed to high speed to low speed.

In the above description, the outlet of the pilot check valve 25 is connected to the circuit 28 communicating with the actuator 21, but the inlet of the vent check valve 25 may be connected to the tank 23 as shown in FIG. In this case, while the actuator 21 is operating, a part of the pressure oil in the accumulator 11 passes through the throttle 19 to the tank 23.
However, since the throttle valve 19 has a small diameter of approximately 1 mm, the amount of flow out is very small and mostly flows from the B port of the logic valve 17 to the A port to the actuator 21.

As explained above, the shut-off control circuit of the present invention has a logic valve disposed between the accumulator and the actuator, and a space between the hydraulic source and the actuator to supply pressure oil from the hydraulic source to the actuator. ,
A second electromagnetic switching valve that discharges the pressure oil in the actuator to the hydraulic tank is installed, so the logic valve can handle high pressure and large volumes of pressure oil from the accumulator, and the movement of the valve body, which is a feature of logic valves, is minimal. The advantage is that the action time is short, the shock is small, and there is no relief from the accumulator. In addition, the speed of the actuator can be controlled by the low-pressure, small-capacity pressure oil from the hydraulic source that acts through the second electromagnetic switching valve and the pressure oil that acts from the accumulator through the logic valve. Although this is a spool type switching valve, a small volume of low-pressure pressure oil is applied from a pressure oil source, and oil from the logic valve direction acts on the actuator without leaking.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a conventional example, and FIG. 2 is a circuit diagram of an embodiment of the present invention. FIG. 3 is a diagram showing another embodiment of the present invention. 11... Accumulator, 17... Logic valve, 18... Check valve, 19... Throttle valve B, 20...
... Throttle valve A, 21... Actuator, 24...
Solenoid switching valve, 25... Pilot check valve, 26...
...first pilot circuit, 27...second pilot circuit.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. In a shut-off control circuit that controls the flow of pressure oil between an accumulator storing pressure oil supplied from a hydraulic source and an actuator operated by the pressure oil from the accumulator, an accumulator that introduces pressure oil from the source to a pressure set in the relief valve via the first electromagnetic switching valve and the check valve; A second electromagnetic switching valve that supplies pressure oil from a hydraulic pressure source to the actuator and discharges pressure oil in the actuator to an oil tank is installed in a circuit that connects the actuator operated by the pressure oil of the accumulator. A first pilot branching from a logic valve, a circuit connecting the accumulator and the inlet of the logic valve, and having two check valves and a throttle valve with a small opening in series, communicating with the pilot chamber of the logic valve. a second pilot circuit branching from the circuit connecting the logic valve outlet and the actuator and communicating between the two throttle valves in the first pilot circuit via a pilot check valve; and a hydraulic source. and the pilot check valve, and controls the opening and closing of the third pilot circuit in the pilot check valve.
A first pilot circuit acts on the pilot chamber of the logic valve to open and close the logic valve by controlling pressure oil from a first pilot circuit, and also controls the speed of the actuator in cooperation with the hydraulic pressure source. A shut-off control circuit characterized by: 2. Claim No. 2, characterized in that the second pilot circuit branches from between two throttle valves in the first pilot circuit and returns to the tank via a pilot check valve. Shut-off control circuit according to item 1.