JP3087986B2 - Discharge port emergency shut-off device of shield machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an emergency shut-off device for a discharge port of a shield machine, and more particularly, to a discharge port of a screw conveyor for discharging excavated earth and sand. The present invention relates to a device for performing an emergency shutoff operation in an emergency where opening and closing operations cannot be performed.

[0002]

2. Description of the Related Art FIGS. 2 and 3 show an example of a conventional shield excavator provided with a conventional discharge opening emergency cutoff device. 2 and 3, reference numeral 1 denotes a shield main body, 2 denotes a partition wall that partitions the shield main body 1 into a face side and an inboard side, and 3 denotes a cutter that is rotatably supported at a front portion of the shield main body 1 and excavates a ground. head,
4 is a cutter driving device for rotating the cutter head 3, 5 is a cutter chamber for taking in excavated earth and sand, 6 is a screw conveyor which is installed through the partition wall 2 and discharges earth and sand from the cutter chamber 5, and 7 is a screw conveyor for discharging the screw conveyor 6. Tachiguchi, 8
Reference numeral 9 denotes a gate for discharging holes, and 9 denotes a gate jack for opening and closing the gate 8.

Next, the opening and closing operation of the discharge port gate 8 will be described with reference to FIG. Normally, a check valve 13 is provided from a hydraulic source 12 in which a hydraulic pump 10 and a relief valve 11 are combined.
Pressure oil is sent to the electromagnetic switching valve 14 via the -1 and the flow of the pressure oil is switched to be supplied to the gate jack 9 by the selective excitation of the solenoids a and b from an operation panel (not shown). 8 is performed. at the same time,
The pressure oil from the hydraulic pressure source 12 flows into the accumulator 15 of the emergency shutoff hydraulic circuit through the check valve 13-2, and accumulates the pressure to a specified pressure.

Normally, the discharge port gate 8 is opened when the excavation is started and closed when the excavation is stopped. However, during the excavation, the hydraulic pump 10 stops due to a power failure or the like, and the electromagnetic switching valve 14 becomes inoperable. In some cases, the gate opening / closing operation cannot be performed normally. In that case, accumulator 1
5, the stop valve 16 at the subsequent stage is opened, and the pressure oil accumulated in the accumulator 15 is discharged to the gate jack 9 through the manual switching valve 17, thereby urgently shutting off the discharge port gate 8, and from the discharge port 7. Prevent the eruption of groundwater and earth and sand. When the discharge gate 8 catches foreign matter such as gravel at the time of emergency shut-off, the manual switching valve 17 operates the gate jack 9 in both opening and closing directions so that the gate is returned to the opening direction and the foreign matter can be removed. It is possible. The stop valve 16 is always closed in order to prevent a decrease in the accumulated pressure of the accumulator 15 due to an internal leak of the manual switching valve 17.

[0005]

Conventionally, there is a conventional discharge port emergency shutoff device in which an emergency shutoff operation of a discharge port gate is performed by using pressure oil accumulated in an accumulator as described above. However, the above prior art has the following problems.

1) Since the hydraulic pressure source for accumulating pressure in the accumulator is the same as the hydraulic pressure source for normally opening and closing the discharge gate, the maximum value of the accumulated pressure is equal to the rated operating oil pressure of the gate jack. As the pressure oil is released from the accumulator at the time of emergency shutoff, the internal pressure of the accumulator, that is, the hydraulic pressure supplied to the gate jack, decreases. For this reason, sufficient operating force of the gate jack at the time of emergency shutoff cannot be obtained.

2) If the operating pressure at the time of emergency shutoff is to be increased while maintaining the same pressure of the hydraulic pressure source, the volume of the accumulator must be increased in order to reduce a decrease in the hydraulic pressure supplied to the gate jack. The installation space becomes large, and it becomes difficult to install a small-diameter shield excavator, or the working space in the aircraft cannot be sufficiently secured.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a shield machine in which the operation force of a gate jack at the time of emergency shutoff is increased without increasing the volume of the accumulator, and the emergency shutoff operation of the gate for the discharge port can be reliably performed. An object of the present invention is to provide a discharge opening emergency shutoff device.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above object, according to the present invention, normally, pressure oil from a hydraulic source is supplied to a gate jack through an electromagnetic switching valve to open and close a gate for a discharge port of a screw conveyor. Separately from the hydraulic circuit to be operated, the pressure oil from the hydraulic source is stored in the accumulator, and the stored pressure oil is discharged to the gate jack through the manual switching valve to perform an emergency shutoff operation of the gate for the discharge port. In the discharge port emergency shutoff device of the shield machine equipped with a hydraulic circuit to be operated, the pressure oil accumulated in the accumulator is a higher pressure hydraulic pressure that is different from a hydraulic pressure source for opening and closing the discharge port gate at normal times. In the event of an emergency shutdown, the pressure oil released from the accumulator is reduced to the rated operating oil pressure of the gate jack by a pressure reducing valve and supplied to the gate jack. Characterized in that way the.

[0010]

With the above construction, the accumulated pressure of the accumulator is increased, and the accumulator internal pressure changes from the maximum value of the accumulated pressure to the rated operating oil pressure of the gate jack set in the pressure reducing valve as the pressure oil is released from the accumulator during an emergency shutoff. During this time, the hydraulic pressure supplied to the gate jack can be maintained at the rated hydraulic pressure.

In general, when the accumulated pressure of the accumulator is increased, the initial velocity of the pressure oil discharged from the accumulator is increased. Therefore, the polytropic exponent when the gas charged in the accumulator is expanded is increased (the state change is adiabatic). (Close to change), the available amount of released oil tends to be less, but in this regard, adding a restrictor to the supply path of pressure oil from the accumulator to the gate jack expands the gas within the accumulator. In this case, the polytropic index can be improved (the state change approaches an isothermal change), and the amount of released oil that can be used can be increased.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention. In FIG. 1, the same parts as those in FIG.

Reference numeral 12-1 denotes a low-pressure hydraulic power source for opening and closing the discharge gate normally during normal operation. The low-pressure hydraulic power source comprises a combination of a low-pressure pump 10-1 and a low-pressure relief valve 11-1.
2, the supply oil pressure is equal to the rated operating oil pressure of the gate jack 9. Reference numeral 12-2 denotes a high-pressure hydraulic source for accumulating pressure in the accumulator 15 of the emergency shut-off hydraulic circuit, which is composed of a combination of a high-pressure pump 10-2 and a high-pressure relief valve 11-2. 1 supply oil pressure, that is, the rated operating oil pressure of the gate jack 9 is set to 210
kgf / cm ² , 350 kgf higher than that
/ Cm ² . This high pressure hydraulic source 12-
2 can be shared with a hydraulic source for other high-pressure hydraulic equipment such as a shield jack mounted on a shield machine.

Reference numeral 18 denotes a pressure reducing valve provided in a pressure oil supply path from the accumulator 15 to the gate jack 9, and its set pressure is equal to the rated operating oil pressure of the gate jack 9.
Reference numeral 19 denotes a throttle which is added as necessary to a pressure oil supply path from the accumulator 15 to the gate jack 9 in order to improve a polytropic index when discharging the pressure oil accumulated in the accumulator 15, and is a throttle valve or an equivalent thereof. It is composed of a thin tube with the function of.

This embodiment operates as follows. Normally, pressure oil is sent from the low pressure hydraulic power source 12-1 to the electromagnetic switching valve 14 via the check valve 13-1, and the flow of the pressure oil is switched by the selective excitation of the solenoids a and b from an operation panel (not shown). Thus, the opening / closing operation of the discharge port gate is performed.
At the same time, pressure is accumulated in the accumulator 15 with the pressure oil supplied from the high pressure hydraulic source 12-2 through the check valve 13-2, and during the excavation, the low pressure hydraulic source 12-1, the high pressure hydraulic source 12
When the supply of the pressure oil from -2 is stopped, the stop valve 16 is opened, and the pressure oil discharged from the accumulator 15 is supplied to the gate jack 9 through the pressure reducing valve 18, the throttle 19 and the manual switching valve 17, thereby discharging the oil. Emergency shut-off operation of the gate for Doguchi At this time, the hydraulic pressure supplied to the gate jack 9 is such that the internal pressure of the accumulator 15 changes from the maximum value of the accumulated pressure to the set pressure of the pressure reducing valve 18 (for example, 350 kgf / cm ² → 210 kgf / cm ² ). Rated operating oil pressure (210 kgf in this example)
/ Cm ² ).

[0017]

According to the present invention, the accumulated pressure of the accumulator for accumulating pressure oil, which is a power source at the time of emergency closing of the discharge port, is increased, and the accumulator internal pressure is reduced from the maximum value of the accumulated pressure by discharging the pressure oil. , The supply hydraulic pressure to the gate jack can be maintained at the rated operating hydraulic pressure, so that the operating force at the time of emergency shutoff can be sufficiently ensured.

Furthermore, if the operating force is the same, the accumulator can be made smaller than before, and it becomes easier to mount the accumulator on a small-diameter shield excavator.

Further, by adding a throttle to the pressure oil supply path from the accumulator to the gate jack, the polytropic index when the gas charged in the accumulator expands with the release of the pressure oil is improved, and the available amount of released oil is reduced. Since it can be increased, the hydraulic oil amount at the time of emergency shutoff can be sufficiently secured.

[Brief description of the drawings]

FIG. 1 is a hydraulic circuit diagram showing one embodiment of the present invention.

FIG. 2 is an overall cross-sectional view of a shield machine provided with a discharge port emergency shutoff device.

FIG. 3 is an enlarged view of the vicinity of a discharge opening of FIG. 2;

FIG. 4 is a hydraulic circuit diagram showing a conventional discharge opening emergency shutoff device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shield body, 6 ... Screw conveyor, 7 ... Discharge port, 8 ... Gate for discharge port, 9 ... Gate jack, 12-
DESCRIPTION OF SYMBOLS 1 ... Low-pressure hydraulic power source, 12-2 ... High-pressure hydraulic power source, 14 ... Electromagnetic switching valve, 15 ... Accumulator, 17 ... Manual switching valve, 18
... pressure reducing valve, 19 ... throttle.

Claims (2)

(57) [Claims] 1. Normally, apart from a hydraulic circuit for supplying pressure oil from a hydraulic source to a gate jack through an electromagnetic switching valve to open and close a discharge gate of a screw conveyor,
Shield excavation provided with a hydraulic circuit that accumulates pressure oil from a hydraulic source in an accumulator and discharges the accumulated pressure oil to the gate jack through a manual switching valve to perform an emergency shutoff operation of the discharge port gate In the discharge port emergency cutoff device of the machine, the pressure oil accumulated in the accumulator is supplied from a hydraulic source of a higher pressure different from the hydraulic source for opening and closing the discharge port gate at normal time, and at the time of emergency cutoff An emergency discharge device for a shield excavator, wherein the pressure oil discharged from the accumulator is reduced to a rated operating oil pressure of the gate jack by a pressure reducing valve and supplied to the gate jack. 2. The emergency discharge opening device for a shield machine according to claim 1, wherein a throttle is added to a pressure oil supply path from the accumulator to the gate jack.