JPS58134205A - Remaining pressure exhaust device - Google Patents

Abstract

PURPOSE:To exhaust all of the remaining pressure in a circuit covering from a remaining pressure exhaust valve to a cylinder by connecting an open-close valve to the secondary port of a changeover valve. CONSTITUTION:After a changeover valve 2 is set at the neutral position, and as a three-way valve 18 is changed over to the exhaust position, the air pressure within a conduit 3 is exhausted. Therefore, the pressure in the pilot portion of each open-close valve 11a, 11b is also exhausted through conduit 12a, 12b and the open-close valves 11a, 11b are changed over to the communicating position by a spring. Accordingly, the air pressure in a conduit 5 and in both cylinder chamber (C1), (C2) of a cylinder 4 is exhausted through the conduit 13, the open- close valve 11 and the conduit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a residual pressure evacuation device in a pneumatic circuit for driving and controlling actuating devices such as cylinders, and more specifically,
The present invention relates to a residual pressure discharge device for discharging air pressure in the circuit during circuit maintenance and inspection in the above-mentioned pneumatic circuit using a center-closed three-position switching valve.

When a center-close type 4-port or 5-port 3-position switching valve is used in the pneumatic circuit that drives and controls actuating devices such as cylinders, when the valve body of the switching valve is in the neutral position, the switching valve and the actuating device It is not possible to discharge the residual pressure in the circuit connecting the

Therefore, in order to discharge the residual pressure in such a circuit for maintenance, inspection, etc., it must be done manually by installing a manual operation valve, or electrically by installing a solenoid valve. In the latter case, there is a problem that the operation becomes complicated, and in the latter case, there is a problem that the control device becomes complicated and large.

Furthermore, when the residual pressure is discharged by the method described above, when the switching valve is operated to operate the actuating device, for example, the cylinder,
The actuating device may operate suddenly, causing damage to the workpiece, jig, etc., or causing personal injury.

The present invention has been made in view of this problem, and its purpose is to eliminate the residual pressure that exists between the center-closed switching valve and the actuating device when the residual pressure on the primary side of the center-closed switching valve is discharged. An object of the present invention is to provide a residual pressure discharge device capable of discharging pressure.

The present invention provides a residual pressure discharge device that is used in combination with a center-closed three-position switching valve to discharge residual pressure from a circuit that communicates the switching valve with an actuating device. An on-off valve that opens and closes using pilot pressure is connected to the side port, and the pilot part of the on-off valve is communicated with the primary side port of the switching valve, so that when the air pressure on the primary side of the switching valve is discharged, the secondary side The air pressure is also discharged.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a residual pressure evacuation device according to the present invention will be described below with reference to the drawings in connection with a pneumatic circuit for driving a cylinder.

In FIG. 1, a circuit diagram of a residual pressure evacuation device according to this embodiment is shown. In the figure, 1 is a pneumatic pressure source, 2 is a known center-closed three-position switching valve whose primary side, that is, an input boat, is connected to the pneumatic source 1 via a conduit 3;
4 is an actuating device or cylinder connected to the two secondary sides or output ports of the switching valve 2 via conduits 5 (5a, 5b), and 6 (6a, 6b) are connected to the exhaust ports of the switching valve 2, respectively. These exhaust mufflers are conventional cylinder drive control circuits, and the residual pressure evacuation device 10 (inside the chain line frame) of this embodiment is provided in this circuit.

The residual pressure discharging device 10 includes a pilot pressure-operated on-off valve 11' ( 11a, 1lb
), the pilot part 110 of each on-off valve 11 and the conduit 12
(12a, 12b)
(14a, 14b) and air reservoir chamber 15 (15a.

15b), and a conduit 17 (17a) between the pilot part 110 of the valve 11 and the conduit 5 (5a, 5b) for each opening and closing.

check valves 16 (16
a, 16b) and a conduit 3 between the air pressure source 1 and the switching valve 2.
It has a 30,000 valve 18 for discharging residual pressure connected in the middle.

In the residual pressure discharge valve configured as described above, when operating the cylinder 4, the three-way valve 18 is placed in the communicating position, and the switching valve 2 is operated to operate the cylinder 4. In this case conduit 3,
If air pressure exists in the cylinder 5, the air pressure acts on the pilot part 110 of each on-off valve to keep the on-off valve in a non-communicating position, so the operation of the cylinder is not affected by the residual pressure discharge device.

Next, when the switching valve 2 is placed in the neutral position and the three-way valve 18 is switched to the exhaust position as shown in FIG. 1, the air pressure inside the conduit 3 is exhausted, so that the air pressure in the conduit 12a is removed.

The pressure in the pilot portion of each on-off valve 11a, llb is also exhausted through 12b, and the on-off valve is switched to the communicating position by the action of the spring. Therefore, the air pressure inside the conduit 5 (5a, 5b) and the cylinder chamber CI + 02 of the cylinder 4 is also the same as that of the conduit 13 (1'3a, 13b) and the on-off valve 11 (l).
la, lb) and via conduits 12 (12a, 12b).

Therefore, the cylinder 4 can be replaced, repaired, inspected, etc. safely.

After inspection, repair, or replacement of the cylinder 4, etc. is completed, by switching the three-way valve 18 to the communication position, the cylinder 4 can be operated in the normal operating state by simply switching the switching valve 2 as described above. become.

That is, return the 3-way valve to the communicating position and open the conduit 3°12 (12
a, 12b, ) are communicated with an air pressure source, and the pressurized air flows through the on-off valves 11a, llb and the conduit 13a.

The cylinder chamber CI $ C2 of the cylinder 4 is supplied and filled via 5a and 1'3b, 5b, respectively.
At the same time, the throttles 14a, 14b and the air chambers 15a, 15
Since the air is supplied to the pilot section via b, the opening/closing valve is placed in the non-communicating position with a specific delay depending on the diameter of the throttle and the volume of the air reservoir.

In this case, depending on the position of the piston 40 of the cylinder 4, one of the cylinder chambers, for example C2, may be much smaller than the other C1, and in this case the pressure in the conduit 5b reaches a constant value much earlier than in the conduit 5a. However, the pressure acts on the pilot part of the on-off valve 11b via the check valve 16b and switches the on-off valve 11b to the non-communicating position earlier than 1.1a, so the piston 40 moves rapidly. A structure is shown in which the configuration except for 18 is incorporated into the main body 100 as a unit. In the figure, the through holes 101 form the conduits 3 and 12 of FIG.
02 (102a, 102b) are conduits 5 (5a, 5b) and 13 (13a) in FIG. 1, respectively.

13b).

The on-off valves 11a, llb are movably inserted into stepped holes 103 (103a, 103b) of the main body 100, and the valve bodies 111a, 1llb are biased to the retracted position by springs 112a, 1.12bK. and a pilot portion 110a at the end of the valve body.

When pilot pressure is introduced into 110b, the valve body moves forward and closes the through holes 104a and 1''04b that communicate the through hole 101 and the holes 102a and 102b.

Air reservoir chambers 15a and 15b are formed in the main body 100 and communicate with the through hole 101 through orifices 16a and 16b.
lb pilot sections 110a and 110b, respectively. The main body 100 is further formed with holes 105a and 105b that communicate with the holes 102a and 102b and the pilot portions 110a and 110b, respectively, and check valves 17a and 17b are housed in the holes 105a and 105b, respectively.

The residual pressure discharging device unitized in one main body in this way, except for the residual pressure discharging valve, that is, the three-way valve 18, is arranged and fixed between the switching valve 2 and the sub-plate 7. port P1 is connected to the air pressure source 1 via a three-way valve]8, and port P2. Just connect P3 to cylinder 4 and the first
It is colored orange so that the circuit shown in the figure is configured. For this purpose, as mentioned above, the sub-plate 7 should be
and the switching valve 7, for example, through holes 107a, 107b, and 108a shown in broken lines.

108b etc. may be formed.

Note that a pop-out prevention device may also be accommodated within the main body 100.

4. As is clear from the above explanation, according to the present invention, a residual pressure discharge valve is provided upstream of the center-close type switching valve, and by simply operating the residual pressure discharge valve, the flow from the residual pressure discharge valve to the cylinder can be carried out. Not only can all residual pressure in the circuit be discharged, but also the cylinder piston can be prevented from popping out when the cylinder is restored to its starting state or when the cylinder is operated.

As shown in Fig. 2, the piping work will be simplified if the on-off valve, check valve, throttle, and air reservoir are integrated as a unit.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the residual pressure evacuation device according to the present invention, and Fig. 2 shows the residual pressure evacuation device of Fig. 1, except for the three-way valve, integrated into the main body as one unit. FIG. 3 is a cross-sectional view showing the provided configuration, and FIG. 3 is a diagram showing an example of use of the device of FIG. 2. 1: Air pressure source 2: Switching valve 4: Actuation device (cylinder) 10: Residual pressure discharge device 11
: Open/close valve 14: Throttle ] 5: Air reservoir chamber 16: Check valve
18: Residual pressure release valve% Applicant: CKD Co., Ltd. (2 others)

Claims (1)

[Claims] 1. In a residual pressure discharge device that is used in combination with a center-closed three-position switching valve and discharges residual pressure from a circuit that communicates the switching valve with an actuating device, the switching valve A residual pressure discharge device characterized in that an on-off valve that opens and closes by pilot pressure is connected to a port on the secondary side of the valve, and a pilot portion of the on-off valve is communicated with a primary side boat of the switching valve. 2. The residual pressure discharge device according to claim 1, characterized in that an air reservoir chamber and a check valve are connected in series in a circuit connecting the pilot section and the primary port of the switching valve. .