JPH04327696A - Sealing device for central shaft of shield excavator - Google Patents

Abstract

PURPOSE:To prevent the progress of the damage of a sealing section and a mechanical system, and to enable restoration easily in a short time by early catching the lowering of the hydraulic pressure of lubricating oil fed between seals and oil leakage due to the damage of the contact surfaces of the seals and a central shaft in a sealing device hermetically sealing the main-body partition wall of a shield excavator and the central axis, on which a cutter wheel or an agitator is mounted. CONSTITUTION:A pressure detecting means 27 being connected to a lubricating piping 25 supplying an oil chamber 20 among seals with lubricating oil and emitting an oil-pressure lowering signal when lubricating oil pressure abnormally lowers and a flow detecting means 31 being inserted near the lubricating hole 21 of the lubricating piping 25 and emitting a flow excess signal when the flow rate of lubricating oil abnormally increases are provided. A signal processing means 28 commands alarm display or commands the stoppage of a cutter when either of the oil-pressure lower signal or the flow excess signal is input.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a shield excavator equipped with a center shaft type cutter wheel or an agitator for agitating earth, sand, and muddy water. The present invention relates to a center shaft sealing device that penetrates through the center shaft and seals between the center shaft and the center shaft to which a cutter foil or agitator is attached to prevent dirt and mud from entering from the face side.

0002

[Prior Art] Conventionally, as a central shaft sealing device for a shield tunneling machine, an oil chamber is provided between the seal stages along the outer peripheral surface of the central shaft, lubricating oil is supplied to this oil chamber through an oil supply hole, and the oil chamber is constantly supplied with lubricating oil. Some devices are designed to lubricate the sliding contact surfaces of the central shaft and the seal by filling them with lubricating oil.

An example of a shield tunneling machine having such a central shaft sealing device will be explained with reference to FIGS. 3 and 4.

As shown in FIG. 3, a bulkhead 2 is integrally provided at the front of the shield body 1 to partition the in-machine space and the face side, and a gear case 3 is provided at the center end surface of the bulkhead 2 on the inside of the machine. is installed. Bulkhead 2 and gear case 3
A central shaft 4 passing through the partition wall 2 is supported, a cutter wheel 5 for excavating the earth E is attached to the front end of the central shaft 4, and a swing gear 6 is attached to the intermediate portion. The swing gear 6 meshes with a pinion 8 attached to the output shaft of a drive motor fixed to the gear case 3, such as a hydraulic motor 7, and transmits drive torque to the central shaft 4. Further, behind the partition wall 2, a shield jack 9, a screw conveyor 10 for earth removal, etc. are installed.

As shown in FIG. 4, a bearing metal 11 that supports the central shaft 4 is attached to the center of the partition wall 2, and a seal case 12 is fixed with bolts 13.

[0006] Inside the seal case 12, there is a gland packing 14 for preventing dirt and mud from entering from the face side.
A gasket 16 is attached to press down the U packing 15 and the gland packing 14, and a cover 17 is fixed to the end surface of the seal case 12 on the gasket 16 side with bolts 18.

In the above configuration, the cutter wheel 5 is rotated by the hydraulic motor 7 to excavate the ground E, and the excavated earth and sand 19 is carried out rearward by the screw conveyor 10 from a chamber formed on the back side of the cutter wheel. Ru.

Next, a conventional seal protection form will be explained using FIG. 5. One end of an oil supply hole 21 provided through the seal case 12 is opened in an oil chamber 20 surrounded by the outer circumferential surface of the central shaft 4, the seal case 12, and the two stages of U packings 15-1 and 15-2, front and rear. The other end of the oil supply hole 21 is connected to the discharge side of the oil supply pump 24 via the oil supply pipe 25, and the suction side of the oil supply pump 24 is connected to the oil reservoir 22 via the suction pipe 23. Further, a relief valve 26 is connected between the oil supply pipe 25 and the suction pipe 23. Generally, the lower part of the gear case 3 shown in FIGS. 3 and 4 is used as an oil reservoir 22, which also serves as an oil reservoir for lubricating the tooth surface of the drive gear.

When the oil supply pump 24 is operated, the oil reservoir 2
2 lubricating oil is supplied to the oil chamber 20 between the seal stages through the oil supply pipe 25 and the oil supply hole 21. When the oil chamber 20 is filled with lubricating oil, the oil pressure increases, and when it exceeds the set pressure of the relief valve 26, the relief valve 26 operates to release the pressure oil to the suction pipe 23 side. Now, the set pressure of the relief valve 26 is set to be lower than the sum of the elastic restoring force of the U-packing 15-1 itself in the previous stage and the pressure of earth and sand and muddy water entering from the face side beyond the gland packing 14. When set, normally the lubricating oil discharged from the oil supply pump 24 is almost the entire amount, excluding a small amount of leakage used for interfacial lubrication of the sliding contact surfaces of the seals (U packings 15-1 and 15-2). returns to the oil sump 22 through the relief valve 26. At the same time,
Lubricating oil is always maintained at a constant pressure in the oil chamber 20 between the seal stages, and the lubricating oil causes the U-packing 15 to
The sliding contact surfaces between -1 and 15-2 and the central shaft 4 are maintained in a good lubricated state.

0010

[Problems to be Solved by the Invention] In the above conventional technology, the sliding contact surface of the seal is lubricated by lubricating oil that is constantly supplied from the oil reservoir in the gear case to the oil chamber between the seal stages, so it is difficult to maintain the lubrication system. Although it is easy to manage, oil pressure may drop due to oil pump malfunction or oil leakage from oil supply piping or suction piping.
Furthermore, there is a lack of consideration for abnormalities such as oil leakage due to damage to the sliding contact surface between the center shaft and the seal. For example, oil leakage may occur due to failure of the oil supply pump or damage to the oil supply piping or suction piping, resulting in a drop in lubrication oil pressure. Even if the cutter wheel continues to rotate, the cutter wheel continues to rotate, resulting in heat generation and abnormal wear of the seal due to lack of oil, deformation of the seal due to heat generation, and intrusion of soil particles into mechanical systems such as bearings and gear cases caused by seal wear and deformation. , there is a high possibility of causing serious damage such as damage to various parts of the mechanical system that would make it impossible to continue the shield work. Once the above-mentioned failure occurs, it will take a considerable amount of time and time to recover, which may cause major problems such as delays in shield construction.

Furthermore, if there is a scratch on the sliding contact surface of either the seal or the central shaft from the beginning or if a scratch occurs during excavation, lubricating oil may leak to the outside through the gap.
Since the amount of leakage exceeds the amount of lubricating oil leaked from normal interfacial lubrication, the lubricating oil in the oil reservoir is gradually lost, and eventually the oil level in the oil reservoir becomes lower than the opening of the suction pipe, and the seal sliding contact surface During this time, damage to the seal and the sliding contact surface of the center shaft may progress, resulting in a situation where repair measures such as seal replacement require a considerable amount of time and time.

[0012] The above description has been made regarding an example of a central shaft sealing device for a cutter foil, but similar problems occur in a central shaft sealing device for an agitator used for stirring earth, sand, or muddy water in a chamber.

The first object of the present invention is to prevent various failures caused by a drop in lubricating oil pressure in a central shaft sealing device for a shield excavator that constantly supplies lubricating oil to an oil chamber provided between seal stages. The goal is to prevent damage at a minor stage and avoid serious damage such as delays in shield construction.

[0014] A second object of the present invention is to provide a center shaft seal device for a shield excavator that constantly supplies lubricating oil to an oil chamber provided between seal stages. The goal is to catch oil leaks caused by surface damage at a minor stage, prevent further damage, and avoid serious damage such as delays in shield construction.

[0015]

[Means for Solving the Problems] In order to achieve the above first object, the invention as claimed in claim 1 provides a system for providing lubricating oil in the pipe, which is connected in the middle of a lubricating pipe that supplies lubricating oil to an oil chamber between seal stages. Equipped with a pressure detection means that outputs an oil pressure drop signal when the oil pressure drops abnormally, and a signal processing means that issues an alarm display or commands a cutter stop when the oil pressure drop signal is input. It is characterized by

[0016] In order to achieve the first and second objects, the invention according to claim 2 provides an oil supply pipe that is connected in the middle of an oil supply pipe that supplies lubricating oil to the oil chamber between the seal stages, and that is connected to the lubricating oil pressure inside the pipe. a pressure detection means that outputs an oil pressure drop signal when the oil pressure decreases abnormally; and a pressure detection means inserted near the oil supply hole of the oil supply pipe,
A flow detection means outputs an excessive flow signal when the flow rate of lubricating oil in the pipe increases abnormally, and the excessive flow signal is input when the oil pressure drop signal is input and even when the oil pressure drop signal is not input. The present invention is characterized by comprising a signal processing means for commanding an alarm display or a command to stop the cutter when the cutter is cut.

[0017]

[Operation] The pressure detection means is connected in the middle of the oil supply pipe, and is used when the lubricant oil pressure in the pipe drops abnormally, i.e., when the oil pressure drops below the normal rated oil pressure due to a failure of the oil supply pump, damage to the oil supply pipe or suction pipe, etc. Outputs a low oil pressure signal. In addition, the flow rate detection means is inserted near the oil supply hole of the oil supply pipe, and when the lubricant flow rate in the pipe increases abnormally,
That is, an excessive flow rate signal is output when the flow rate increases from the normal specified flow rate, which corresponds to a small amount of leakage due to interfacial lubrication of the seal sliding contact surface.

In the invention as claimed in claim 1, when the oil pressure drop signal is input, the signal processing means commands an alarm display or commands to stop the cutter, so that the seal sliding contact surface is prevented from running out of oil. This can be prevented from occurring.

In the invention as set forth in claim 2, when the excessive flow rate signal is inputted even if the oil pressure drop signal is not inputted, the signal processing means commands an alarm display or commands to stop the cutter. Progression of damage to the seal or the sliding contact surface of the center shaft can be prevented at a mild stage before the oil pressure drops.

[0020]

Embodiments Hereinafter, embodiments of the present invention will be explained with reference to FIGS. 1 and 2.

FIG. 1 is a diagram showing a cross-section of the seal portion of the first embodiment corresponding to claim 1 and the flow of signals in the lubricating oil piping and electrical system, and FIG. 2 is a diagram showing the seal of the second embodiment corresponding to claim 2. 5 is a diagram showing a cross section and the flow of signals in the lubricating oil piping and the electrical system. The lubricating oil piping is shown by a solid line, and the signal flow of the electrical system is shown by a broken line, and the same reference numerals as in FIG. 5 indicate the same parts. 1 and 2, inside the seal case 12, there are two stages of U packings 15-1 and 15 in the front and rear as dirt seals.
-2 is attached, and an oil chamber 20 surrounded by a central shaft 4 with a cutter foil attached between the seal stages, a seal case 12, and U packings 15-1 and 15-2 is provided. An oil supply hole 21 provided through the seal case 12 is open in the oil chamber 20, and the other end of the oil supply hole 21 is connected to the discharge side of the oil supply pump 24 via an oil supply pipe 25, and the oil supply hole 21 is connected to the discharge side of the oil supply pump 24 through the oil supply pipe 25. The suction side of the pump 24 is connected to the oil reservoir 22 via a suction pipe 23. Further, a relief valve 26 is connected between the oil supply pipe 25 and the suction pipe 23, and when the pressure on the oil supply pipe 25 side exceeds the set pressure of the relief valve 26, the pressure oil is returned to the suction pipe 23 side. Therefore, when the oil supply pump 24 is operating normally, the oil chamber 20 between the seal stages is kept filled with lubricating oil at a specified pressure according to the set pressure of the relief valve 26. The U-packing 15-1 at the front stage is installed in an open state opposite to the oil chamber 20, and the U-packing 15-2 at the rear stage is installed in an open state at the side opposite to the oil chamber 20.
This is to prevent dirt and muddy water that has exceeded 4 from entering the bearing metal 11 side. Therefore, the pressure of earth and sand or muddy water is normally applied to the open side of the U-packing 15-1 in the previous stage, and the U-packing itself also has an elastic restoring force to cope with deformation during installation. By setting the set pressure of the relief valve 26 to be lower than the sum of the force and the pressure of the earth, sand or muddy water, there is usually almost no leakage of lubricating oil from the oil chamber 20, and if it is controlled, Only a very small amount of the lubricating oil used for interfacial lubrication between the sliding contact surfaces of the U-packings 15-1 and 15-2 and the central shaft 4 leaks, and almost the entire amount of lubricating oil discharged from the oil supply pump 24 flows through the relief valve 26.
It returns to the suction pipe 23 side through the lubricating oil, and the oil chamber 20 is always kept filled with lubricating oil at a constant pressure.

Now, suppose that the suction pipe 23 or the oil supply pipe 25
If we assume that an oil leak occurs due to a gap in a piping connection or a flaw in the piping, or if the discharge pressure decreases due to a failure of the oil supply pump 24, the lubricant held in the oil chamber 20 will naturally Oil pressure also decreases. In the first embodiment shown in FIG. 1 and the second embodiment shown in FIG. 2, a pressure detection means 27 is connected in the middle of the oil supply pipe 25 in order to cope with this drop in oil pressure.

The pressure detection means 27 monitors the lubricating oil pressure in the oil supply pipe 25 and outputs an oil pressure drop signal when the pressure falls below a specified pressure. For example, it opens and closes a contact depending on whether the pressure is above the specified pressure, and A pressure switch is used that generates a signal. Alternatively, it may be configured with a pressure sensor that converts pressure into an electrical signal and a comparator that compares and determines the output signal with a reference level.

The pressure detection means 27 is connected to the input side of a signal processing means 28 such as a sequencer, and the output side of the signal processing means 28 is equipped with a cutter drive control circuit 29 built in the shield control panel, a buzzer, and an indicator light. An alarm display 30 is connected to the shield driver's seat, which is installed independently on the driver's seat or incorporated into the operation panel.

When the lubricating oil pressure in the oil supply pipe 25 falls below the specified pressure for some reason, the pressure detection means 27 outputs an oil pressure drop signal, and the signal processing means 28
4 is in the operating state, if a low oil pressure signal is input, a cutter stop command is issued to the cutter drive control circuit 29 to stop driving the cutter wheel, and at the same time command the alarm display 30 to display an alarm. and notifies the driver of low oil pressure. This prevents the seal sliding contact surface from running out of oil, and if the cause of the oil pressure drop is a malfunction in the oil supply pump or an oil leak in the piping, it can be easily recovered by simply repairing the pump and piping. be.

Next, check whether there is any damage on the sliding contact surface of either of the U packings 15-1, 15-2 and the central shaft 4 from the beginning.
Alternatively, assuming that a scratch occurs during excavation, in addition to the small amount of leakage that is normally used for interfacial lubrication of the sliding contact surface, the lubricating oil in the oil chamber 20 may also leak from the gap of the damaged part of the sliding contact surface. may leak outside. If the amount of leakage is small enough to not cause a drop in oil pressure, the lubricating oil in the oil reservoir 22 will gradually be lost, and when the oil level eventually becomes lower than the opening of the suction pipe 23, the oil pressure will only drop. By then, U packing 15-1, 15-
2 or the sliding contact surface of the central shaft 4 may progress, leading to a situation in which recovery measures such as seal replacement require a considerable amount of time and time. In the second embodiment shown in FIG. 2, the oil supply hole 21 of the oil supply pipe 25 is
A flow rate detection means 31 is inserted nearby.

The flow rate detection means 31 monitors the flow rate of lubricating oil in the oil supply pipe 25 and outputs an excessive flow rate signal to the signal processing means 28 when the flow rate increases beyond a specified value. A flow rate sensor is used in which a rotatably supported baffle plate is installed, and when the flow rate (flow velocity) exceeds a specified value, the baffle plate moves due to the dynamic pressure of the fluid, opening and closing the contacts and generating an electrical signal. . Alternatively, the flow rate sensor may be configured to include a flow rate sensor that converts the flow rate into an electrical signal, and a comparator that compares and determines the output signal with a reference level. The flow rate detection means 31 is installed at a position as close as possible to the oil supply hole 21 in order to detect oil leakage caused by damage to the sliding contact surface between the seal and the central shaft separately from oil leakage from the oil supply pipe. In this case, since the flow rate of the lubricating oil to be detected is extremely small during normal operation as described above, the specified value of the flow rate is also extremely small. Therefore, if the normal flow rate is ignored, the flow rate detection means 31 can also be said to simply be a means for determining the presence or absence of a flow.

In this embodiment, when the flow rate of lubricating oil supplied to the oil chamber 20 increases beyond a specified value, the flow rate detecting means 31 outputs an excessive flow rate signal before the oil pressure drops. (The signal processing means 28 issues an alarm display command to the alarm display 30 when an excessive flow signal is input even if a low oil pressure signal is not input, and notifies the driver of an abnormality in the seal section. , it is also possible to command the cutter drive control circuit 29 to stop the cutter and stop the drive of the cutter wheel.Due to shield work, it is also possible to stop the cutter wheel from immediately starting after digging one ring, instead of stopping the cutter wheel immediately. According to this embodiment, damage to the sliding contact surface between the seal and the center shaft can be detected at a mild stage, so if the lubricating oil that was being supplied between the seal stages is replaced with grease, The seal and center shaft can be used as is, and the characteristics of the grease itself will prevent leakage.
It is possible to prevent soil particles from entering, and as a result, the progression of damage to the sliding contact surface can be suppressed.

[0029]

As explained above, according to the invention as set forth in claim 1, the pressure of the lubricating oil supplied between the seal stages is constantly monitored, and an alarm is displayed when a drop in oil pressure is detected. Since the cutter can be stopped, heat generation and abnormal wear of the seal due to lack of oil, deformation of the seal due to heat generation, intrusion of soil particles due to seal abrasion and deformation, progress of abnormal wear of the seal and center shaft due to the intrusion of soil particles. As a result, the invasion of soil particles into various parts of the mechanical system, such as bearings and gear cases, and the resulting damage to various parts of the mechanical system can be prevented in advance or at a minor stage.

Furthermore, according to the second aspect of the invention, the flow rate of the lubricating oil supplied between the seal stages is constantly monitored, and an alarm is displayed or the cutter is stopped when an abnormal increase in the flow rate is detected. Therefore, oil leakage caused by damage to the sliding contact surface between the seal and the center shaft can be detected at an earlier stage than when the lubricating oil pressure decreases, and subsequent damage can be prevented from progressing.

[0031] In this way, oil leakage caused by a drop in lubricating oil pressure and damage to the sliding contact surface between the seal and the center shaft can be detected early and recovered by preventing further damage to the seal and other parts of the mechanical system. This has the effect of making the construction easier, significantly shortening the period required for it, and avoiding serious damage due to delays in shield construction.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a cross section of a seal portion, lubricating oil piping, and signal flow of an electrical system in a first embodiment of the present invention.

FIG. 2 is a diagram showing a cross section of a seal portion, lubricating oil piping, and signal flow of an electrical system in a second embodiment of the present invention.

FIG. 3 is a vertical sectional view showing an example of a shield tunneling machine to which the present invention is applied.

FIG. 4 is a detailed sectional view of a seal portion (portion A in FIG. 3) that is the object of the present invention.

FIG. 5 is a diagram showing a cross section of a seal portion and lubricating oil piping according to the prior art.

[Explanation of symbols]

1...Shield body, 2...Partition wall, 4...Center shaft, 5...Cutter foil, 15-1, 15-2...U packing (seal),
20... Oil chamber between seal stages, 21... Oil supply hole, 24... Oil supply pump, 25... Oil supply piping, 27... Pressure detection means, 28... Signal processing means, 29... Cutter drive control circuit, 30... Alarm indicator, 31 ...Flow rate detection means.

Claims (2)

[Claims] [Claim 1] A partition wall provided at the front part of the shield body;
This is a center shaft sealing device for a shield excavator that penetrates this bulkhead and seals between the center shaft and the center shaft to which a cutter wheel or agitator is attached to prevent the intrusion of earth, sand and muddy water from the face side. An oil supply pipe that supplies lubricating oil to the oil chamber, in which an oil chamber is provided between the seal stages along the line, and lubricating oil is supplied to this oil chamber through an oil supply hole so that the oil chamber is always filled with lubricating oil. A pressure detection means is connected in the middle of the pipe and outputs an oil pressure drop signal when the lubricating oil pressure in the pipe drops abnormally, and a pressure detection means that commands an alarm display or a cutter stop when the oil pressure drop signal is input. A central shaft sealing device for a shield excavator, characterized in that it is equipped with a signal processing means that performs the following steps. [Claim 2] A partition wall provided at the front part of the shield body;
This is a center shaft sealing device for a shield excavator that penetrates this bulkhead and seals between the center shaft and the center shaft to which a cutter wheel or agitator is attached to prevent the intrusion of earth, sand and muddy water from the face side. An oil supply pipe that supplies lubricating oil to the oil chamber, in which an oil chamber is provided between the seal stages along the line, and lubricating oil is supplied to this oil chamber through an oil supply hole so that the oil chamber is always filled with lubricating oil. A pressure detection means is connected in the middle of the pipe and outputs an oil pressure drop signal when the lubricating oil pressure in the pipe becomes abnormally low; a flow rate detection means for outputting an excessive flow rate signal, and a means for instructing an alarm display or stopping the cutter when the oil pressure drop signal is input, and when the oil pressure drop signal is input even if the oil pressure drop signal is not input, the excessive flow rate signal is input. A center shaft sealing device for a shield excavator, characterized by comprising a signal processing means for commanding.