JPS5835850Y2 - Self-priming supply circuit - Google Patents

Description

[Detailed description of the invention] The present invention uses a closed circuit that connects a bidirectional discharge type pump and a bidirectional flow type motor, and a conduit and relief valve that communicate the discharge fluid of the auxiliary pump at the neutral position of the switching valve. It also has an open circuit that returns to the tank, and is configured to replenish the pressure-regulated fluid with the IJ-F valve in this open circuit to the closed circuit, and also to supply the fluid discharged from the auxiliary pump in the open circuit by operating the switching valve. The present invention relates to a replenishment circuit which supplies a supply of water to an actuator and is also used to control the operation of the actuator.

A conventional replenishing circuit of this type is shown in FIG.

This replenishing circuit is a closed circuit in which a bidirectional discharge type variable displacement pump 1 and a bidirectional flow type motor 2 are connected through pipes A and A', and the discharge fluid of the auxiliary pump 6 is connected at the neutral position of the switching valve 9. It also has an open circuit leading back to the tank 12 via the conduit D' and the relief valve 4.

3 and 3' are relief valves for adjusting the pressure of closed circuit pipes A and A', respectively; 7 is a relief valve connected between open circuit pipes D'; and 8 is a relief valve connected between pipes D' and D'. This is a filter inserted between the relief valves 4.

Then, the fluid whose pressure has been adjusted by the open circuit IJ-F valve 4 is supplied from the supply pipe B to the closed circuit pipes A and A' via the check valves 5 and 5', and
The actuator 10 is connected to the pipes E and E' which are blocked at the neutral position of the switching valve 9, and the fluid discharged from the auxiliary pump 6 is supplied to the actuator 10 by switching the switching valve 9.

In such a conventional replenishment circuit, the pressure of the discharge fluid of the bidirectional discharge type variable displacement pump 1, that is, the pressure of the fluid discharged from the pipe A or A
The pressure of ' is regulated by the relief valve 3 or 3', and the bidirectional flow type motor 2 is driven by the pressure-regulated fluid.

When the switching valve 9 is in the neutral position, the discharge fluid of the auxiliary pump 6 returns to the tank 12 through the pipe D', the filter 8, and the relief valve 4, and the fluid whose pressure has been adjusted by the relief valve 4 is sent from the supply circuit B. The line A' or A is supplied via the check valve 5' or 5.

When the switching line 9 is switched, the discharge fluid of the auxiliary pump 6 is supplied to the actuator 10 through the pipes E, E, and E', and the return fluid is supplied to the actuator 10 through the pipes E', D', or E, D. ', is returned to the tank 12 through the filter 8 and the relief valve 4, and the actuator 10 is activated.

At this time, the fluid pressure applied to the actuator 10 is adjusted by the relief valve 7.

Along with the operation of this actuator 10, the fluid whose pressure has been adjusted by the IJ-F valve 4 is transferred to the check valve 5 from the replenishment circuit B.
It is supplied to conduit A' or A via line A' or 5.

In this way, in the conventional supply circuit, the closed circuit pipe A' or A can be supplied with the open circuit auxiliary pump 6, and the actuator 10 can be operated by switching the switching valve 9. Due to open circuit equipment (
In the event of failure of the auxiliary pump 6, filter 8, etc., or damage to the pipe line in the open circuit, fluid supply from the open circuit to the closed circuit will be cut off or insufficient, resulting in cavitation in the closed circuit. Closed circuit equipment (pump 1, motor 2, etc.)
This has the disadvantage that the circuit may be damaged or malfunction, resulting in loss of circuit reliability.

The present invention has been made in order to eliminate the above-mentioned drawbacks, and the suction pipes c and c each have check valves 11 and 11' between the closed circuit pipes A and A' and the tank 12.
' or conduit A.

The above-mentioned drawbacks are solved by connecting the suction pipe C having the check valve 11 via the check valves 5, 5' connected to A' and the supply circuit B, respectively.

Embodiments of the present invention will be described below with reference to the drawings.

In the first embodiment, in the conventional replenishment circuit shown in FIG. 1, as shown in FIG.
Suction pipes c and c' each having check valves 11 and 11' are connected between them.

In addition, in the second embodiment, in the conventional replenishment circuit shown in FIG. 1, as shown in FIG. 3, between the closed circuit pipes A and A' and the tank 12, there are connections to the pipes A and A', respectively. A suction pipe C having a check valve 11 is connected through the check valves 5, 5' and the supply circuit B.

Note that FIG. 3 shows a circuit section corresponding to the circuit section enclosed by the two-dot chain line in FIG.

Since the present invention has the above-described configuration, the bidirectional flow motor 2 is driven, the switching valve 9 is in the neutral position to supply fluid to the closed circuit, and the switching valve 9 is operated to operate and close the actuator 10. The operation of replenishing the fluid to the circuit is as described above.

In the first embodiment shown in FIG. 2, if the auxiliary pump 6 or the like breaks down or the open circuit pipe is damaged for some reason, and the supply of fluid from the open circuit to the closed circuit is cut off or insufficient, the suction The check valve 11' or 11 of the line C' or C opens, sucks in the insufficient amount of fluid from the tank 12, and the check valve 1
1' or 11 to supply the closed circuit line A' or A.

Further, in the second embodiment shown in FIG. 3, when the supply of fluid from the open circuit to the closed circuit is cut off or insufficient for the above-mentioned reason, the check valve 11 of the suction pipe C opens and the insufficient amount of fluid is removed from the tank. 12, and is supplied to the closed circuit conduit A' or A through the check valve 11, the supply circuit B, and the check valve 5' or 5.

As described above, according to the present invention, the conduit A is a closed circuit.

A' and the tank 12 are each provided with a check valve 11.
check valves 5, 5 connected to the suction lines c, c' with 11' or to the lines A, A', respectively;
' and the suction pipe C with the check valve 11 are connected via the replenishment circuit B, so if the open circuit equipment breaks down or the pipe is damaged, fluid cannot be refilled from the open circuit to the closed circuit. Alternatively, the fluid in the tank 12 can be supplied to the closed circuit line A' or A through the suction line C' or C in the tank 12, or the fluid in the tank 12 can be supplied to the closed circuit line A' or A through the suction line C1 or the check valve 5' or 5. Since the closed circuit conduit A' or A can be supplied through the closed circuit, it is possible to avoid damage or failure of the equipment in the closed circuit due to cavitation in the closed circuit, and to ensure the reliability of the circuit.

[Brief explanation of drawings]

Fig. 1 is a connection diagram showing an example of a conventional circuit with replenishment, Fig. 2 is a connection diagram showing a first embodiment of the circuit with replenishment of the present invention, and Fig. 3 is a connection diagram showing main parts of the second embodiment. It is. 1. Bidirectional discharge type (variable displacement) pump, 2.
...bidirectional flow type motor, 4...IJ
IJ-F valve, 5゜51...Check valve, 6...
...Auxiliary pump, 9...Switching valve, 10...
...actuator, 11, 11'...check valve, 12...tank, A, A'...
・Closed circuit conduit, B...Supply conduit, c, c'・
...Suction pipe.

Claims (1)

[Scope of utility model registration request] The bidirectional discharge type pump 1 and the bidirectional flow type motor 2 are connected to the pipe A.
, a closed circuit connected at A', a pipe line that communicates the fluid discharged from the auxiliary pump at the neutral position of the switching valve 9, and an open circuit that returns to the tank 12 via D' and the relief valve 4. The fluid whose pressure has been adjusted by the open circuit relief valve 4 is supplied from the supply pipe B to the closed circuit pipes A and A' via the check valves 5 and 5', and the switching An actuator 10 is connected to the pipes E and E' which are blocked at the neutral position of the valve 9, and the fluid discharged from the auxiliary pump 6 is transferred to the actuator 10 by switching the switching valve 9.
In the replenishment circuit configured to supply water to the tank 12, suction pipes c and c each have check valves 11 and 11' between the pipes A and A' of the closed circuit and the tank 12.
or by connecting a suction pipe C having a check valve 11 via check valves 5, 5' connected to pipes A and A', respectively, and a supply pipe B, capable of self-priming. circuit.