Rotary joint co-rotation detection mechanism

Abstract

To provide a co-rotation detection mechanism for a rotary joint capable of immediately detecting co-rotation when the co-rotation of a fixed housing part of the rotary joint is generated by rotation of a rotating cutter.SOLUTION: Not only a circumferential movement detection part 11 with a specific detection width B is arranged on a tip part in an excavation direction X of a fixed housing part 20a of a rotary joint 20 but also a movement detector 12 detecting movement of the circumferential movement detection part 11 supported by the surface of the rear side in the excavation direction X through a support frame 21 arranged rearward from the surface of the rear side in the excavation direction X of a barrier wall 35 is attached thereon. The movement detector 12 detects the start of co-rotation of the fixed housing 20a of the rotary joint 20 with the cutter 32 through detection of the movement of the circumferential movement detection part 11 beyond the specific detection width b.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a co-rotation detection mechanism for a rotary joint, and more particularly to a co-rotation detection mechanism for a rotary joint in a shield tunneling machine for detecting when a fixed housing part of the rotary joint begins to co-rotate with a rotating cutter. [Background technology]

[0002] For example, a mud pressure shield machine cuts the ground at the tunnel face with a rotary cutter and takes the soil and sand into the cutter chamber. This is then mixed with a liquid chemical, preferably containing a plastic fluidizing agent such as a mud-making agent, which is then supplied to the cutter chamber via the rotary cutter to create plastic fluidized mud. The mud pressure generated by filling the cutter chamber with this mud stabilizes the tunnel face while excavating the ground at the tunnel face. Other shield machines, such as mud water shield machines, also have various chemicals pumped in as needed from behind the partitions that separate the cutter chambers through their respective piping.

[0003] In these shield tunneling machines, the chemical solution fed from behind the partition to the rotating cutter and cutter chamber is supplied to the front rotating cutter, which is driven to rotate, from a rear piping line that does not have a rotation mechanism. Therefore, a known rotary joint is attached to the partition to communicate the chemical solution flow path between them (see, for example, Patent Document 1). The rotary joint attached to the partition includes a fixed housing part that is fixed to the center of the rear surface of the partition in the excavation direction, and a rotating shaft part that is rotatably and liquid-tightly supported via a rotation support part provided in an insertion hole formed in the partition and extends inside the front cutter chamber. The fixed housing part has one or more rotating outer circumferential grooves extending circumferentially therein. The chemical solution fed from the piping lines connected to these rotating outer circumferential grooves can be sent through the rotating outer circumferential grooves to cutter-side piping lines that are piped inside the rotating shaft part that rotates with the rotating cutter and that communicate with the rotating outer circumferential grooves. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2022-85245 Summary of the Invention [Problem to be solved by the invention]

[0005] On the other hand, as described above, the rotating shaft portion of the rotary joint is rotatably and liquid-tightly supported in the insertion hole formed in the partition wall via the rotating support portion. However, since the rotating support portion is attached facing the inside of the cutter chamber, if, for example, excavated soil with large particle size that is being mixed and stirred inside the cutter chamber becomes caught in the rotating support portion and becomes clogged, or if the rotating support portion becomes seized, it is conceivable that the fixed housing portion of the rotary joint attached to the partition wall will rotate along with the rotation of the rotating cutter.

[0006] Preferably, when the rotational torque of the fixed housing part during cutting by the rotating cutter of the shield tunneling machine is not too large, it is possible to detect signs of such co-rotation of the fixed housing part of the rotary joint before it occurs, for example, due to an increase in rotational torque during tunneling.However, if the rotational torque of the rotating cutter of the shield tunneling machine during cutting becomes large, it becomes difficult to reliably detect the increase in rotational torque and accurately detect signs of co-rotation of the fixed housing part.

[0007] Furthermore, if the fixed housing part of the rotary joint rotates in conjunction with the rotation of the rotating cutter, it is thought that this could damage pipes, etc. that are connected to the fixed housing part behind the partition wall in the excavation direction.It is also thought that the rotary joint itself could become detached or fall off the partition wall, which could cause a major accident.Therefore, when the fixed housing part rotates in conjunction with the rotation, it is necessary to be able to immediately and reliably detect this and take appropriate measures, such as stopping the drive of the rotating cutter.

[0008] An object of the present invention is to provide a co-rotation detection mechanism for a rotary joint that can immediately and reliably detect co-rotation of the fixed housing part of the rotary joint caused by the rotation of a rotating cutter, and enable appropriate measures to be taken. [Means for solving the problem]

[0009] The present invention provides a rotary joint co-rotation detection mechanism for detecting when a fixed housing part of a rotary joint that is attached to the center of a partition wall that partitions a cutter chamber in a shield tunneling machine and that allows various chemical solutions sent from the rear in the excavation direction to be supplied to the rotary cutter via piping inside the rotary cutter starts to co-rotate with the rotary cutter, wherein the rotary joint has the fixed housing part fixed to the center part of the partition wall on the rear side in the excavation direction, and the rotary shaft part is rotatably supported in an insertion hole provided in the partition wall and is attached to the partition wall in a state where it extends into the cutter chamber, and the rotary joint The rotating cutter is joined as a single unit to the tip of the rotating shaft in the excavation direction, and a circumferentially moving detectable part with a predetermined detection width is provided on the outer periphery of the tip of the fixed housing part of the rotary joint in the excavation direction, and a movement detector is attached that detects movement of the circumferentially moving detectable part and is supported on the rear surface of the partition in the excavation direction, and the movement detector detects that the circumferentially moving detectable part has moved beyond the predetermined detection width, thereby achieving the above-mentioned object by providing a co-rotation detection mechanism for a rotary joint that detects when the fixed housing part of the rotary joint has started to co-rotate with the rotating cutter.

[0010] In the co-rotation detection mechanism of the rotary joint of the present invention, the circumferential movement detectable portion is a contact convex portion that protrudes radially outward from the outer periphery at the tip of the fixed housing portion in the excavation direction, and has a contact surface portion at its tip that has a predetermined detection width, and the movement detector is a limit switch that is attached with the tip of an abutment pin abutting the abutment surface portion of the abutment convex portion from the radial outside of the fixed housing portion, and it is preferable that the movement detector is configured to detect that the fixed housing portion has started to co-rotate with the rotating cutter when the tip of the abutment pin comes off the abutment surface portion of the abutment convex portion with which it was abutting.

[0011] In addition, in the co-rotation detection mechanism for a rotary joint of the present invention, it is preferable that the shield tunneling machine is a mud pressure type shield tunneling machine. [Effects of the Invention]

[0012] According to the co-rotation detection mechanism for a rotary joint of the present invention, when co-rotation of the fixed housing part of the rotary joint occurs due to the rotation of the rotating cutter, this can be detected immediately and reliably, allowing appropriate measures to be taken. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a vertical cross-sectional view of a mud pressure type shield tunneling machine that employs a co-rotation detection mechanism for a rotary joint according to a preferred embodiment of the present invention. [Figure 2] FIG. 2 is a front view of the shield machine of FIG. 1, as seen from the front side in the excavation direction. [Figure 3] FIG. 2 is an enlarged cross-sectional view of a portion A in FIG. 1, illustrating a co-rotation detection mechanism of a rotary joint according to a preferred embodiment of the present invention. [Figure 4] FIG. 2 is an enlarged cross-sectional view of a main portion illustrating a co-rotation detection mechanism of a rotary joint according to a preferred embodiment of the present invention. [Figure 5] FIG. 5 is an enlarged rear view of the main part of FIG. 4, seen from the rear side in the excavation direction, illustrating a co-rotation detection mechanism for a rotary joint according to a preferred embodiment of the present invention. [Figure 6] Explaining the fixed convex plate portion and base metal portion to which the detected metal is attached, (a) is a simplified side view, and (b) is a simplified rear view of (a) as seen from the rear side in the excavation direction. [Figure 7] Explaining the detected metal fittings, (a) is a side view, and (b) is a rear view of (a) seen from the rear side in the excavation direction. [Figure 8] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] A rotary joint co-rotation detection mechanism 10 (see Figures 4 and 5) according to a preferred embodiment of the present invention is preferably used in an earth pressure type shield tunneling machine 30 shown in Figure 1 as a detection mechanism for instantly and reliably detecting co-rotation of the fixed housing portion 20a of the rotary joint 20 attached to the central portion of the partition wall 35 that separates the cutter chamber 31 due to the rotation of the rotating cutter 32, so that appropriate measures can be taken.

[0015] That is, for example, an earth pressure type shield machine 30 cuts the ground at the tunnel face 33 with a rotary cutter 32, and the soil and sand taken into the cutter chamber 31 is mixed with a liquid material, preferably containing a plastic fluidizing agent such as a mud-making agent, as a chemical solution, and stirred to produce plastically fluidized earth, and the ground at the tunnel face 33 is excavated while stabilizing it by the mud pressure generated by filling the cutter chamber 31 with the produced mud. As the shield machine 30 advances while excavating the ground at the tunnel face 33, the plastically fluidized earth is discharged to the rear of the shield machine 30 via a screw conveyor 36, one end of which opens in a partition wall 35.

[0016] Furthermore, in this type of mud pressure shield machine 30, the chemical solution that is sent in from behind the partition wall 35 and supplied to the rotating cutter 32 and cutter chamber 31 is supplied to the rotating cutter 32, which is driven to rotate, from a piping line (not shown) that does not have a rotation mechanism, and so a known rotary joint 20 is attached to the partition wall 35 to communicate the flow path of the chemical solution between them. The rotary joint 20 is composed of a fixed housing part 20a attached to the rear side of the partition wall 35 in the excavation direction X, and a rotating shaft part 20b that is rotatably and liquid-tightly supported and extends into the cutter chamber 31 via a known rotation support part 40 (see Figure 3) provided in an insertion hole 35a formed in the partition wall 35.

[0017] Here, the rotating shaft portion 20b of the rotary joint 20 is rotatably and liquid-tightly supported in an insertion hole 35a formed in the partition wall 35 via a known rotating support portion 40 equipped with a dust wiper and a bearing mechanism. However, since the rotating support portion 40 is attached facing the inside of the cutter chamber 31, if, for example, large-grained excavated soil being mixed and stirred inside the cutter chamber 31 becomes jammed into the rotating support portion 40 or the rotating support portion 40 becomes seized, it is conceivable that the fixed housing portion 33a of the rotary joint 20, which is fixed to the partition wall 35, will rotate in conjunction with the rotation of the rotating cutter 34. If such co-rotation occurs in the rotary joint 20, it is thought that it may damage, for example, the piping connected to the fixed housing part 33a. It is also thought that the rotary joint 20 itself may become detached or fall off the partition wall 35, which could cause a major accident. Therefore, when co-rotation occurs in the fixed housing part 33a, it is necessary to immediately and reliably detect this and take appropriate measures, such as stopping the drive of the rotating cutter 32.

[0018] The co-rotation detection mechanism 10 of the rotary joint of this embodiment is configured to instantly and reliably detect any co-rotation that occurs in the fixed housing portion 20a of the rotary joint 20, which is fixedly attached to the partition wall 35 in this manner, due to the rotation of the rotating cutter 32, and to stop the rotational drive of the rotating cutter 32, preferably via a known interlock mechanism, and to take appropriate measures.

[0019] The rotary joint co-rotation detection mechanism 10 of this embodiment is a detection mechanism for detecting when the fixed housing part 20a of a known rotary joint 20, which is attached to the center of a partition wall 35 that partitions a cutter chamber 31 in, for example, an earth pressure type shield machine 30 shown in Figures 1 and 2, starts to co-rotate with the rotating cutter 32. The rotary joint 20 sends various chemical solutions sent from the rear in the excavation direction X to the rotating cutter 32, thereby enabling the chemical solutions to be supplied to the cutter chamber 31 via piping inside the rotating cutter 32. The rotary joint 20 has the fixed housing part 20a fixed to the center of the partition wall 35 on the rear side in the excavation direction X, for example, via a support frame part 21, and is attached to the partition wall 35 with the rotating shaft part 20b rotatably supported by a known rotation support part 40 provided in an insertion hole 35a formed in the partition wall 35 and extending into the cutter chamber 31, as shown in Figure 3. A rotary cutter 32 is integrally joined to the tip of the rotary shaft 20b in the excavation direction X (see FIG. 1).

[0020] 4 and 5, a circumferential movement detectable part 11 with a predetermined detection width b (see FIG. 5) is provided on the outer periphery of the tip of the fixed housing part 20a of the rotary joint 20 in the excavation direction X, and a movement detector 12 that detects movement of the circumferential movement detectable part 11 is attached to the rear surface of the excavation direction X, for example, via a support frame part 21 that is provided so as to protrude rearward from the rear surface of the partition wall 35 in the excavation direction X. The movement detector 12 detects that the circumferential movement detectable part 11 has moved circumferentially beyond the predetermined detection width b, thereby detecting that the fixed housing part 20a of the rotary joint 20 has started to rotate together with the rotating cutter 32.

[0021] In this embodiment, the circumferential movement detectable portion 11 is preferably a contact protrusion 13 having a contact surface 13a with a predetermined detection width b at its tip, which is provided on the outer periphery of the tip of the fixed housing portion 20a of the rotary joint 20 in the excavation direction X and protrudes radially outward. The movement detector 12 is preferably a limit switch 14 attached with the tip of a contact pin 14a abutting against the contact surface 13a of the contact protrusion 13 from the radial outside of the fixed housing portion 20a. When the tip of the abutment pin 14a disengages from the abutting surface 13a of the abutment protrusion 13 with which it was abutting, it is detected that the fixed housing portion 20a has started to rotate together with the rotating cutter 32.

[0022] In this embodiment, the mud pressure shield machine 30 is preferably a pivotable type, as shown in Figures 1 and 2, and as described above, has the same structure as known mud pressure shield machines. In addition to the rotating cutter 32, bulkhead 35, cutter chamber 31, and cutter drive unit 34, the shield machine 30 also includes a forward shell 37a, a rear shell 37b, a shield jack 38, a pivotable jack 39, a rotary joint 20, and an erector unit 41. Inside the rear shell 37b, the erector unit 41 assembles segments 42 into a ring shape to sequentially form a primary lining 43. By extending the shield jack 38 while receiving a reaction force from the primary lining 43 made of the formed segments 42, the shield machine can advance in the excavation direction X while cutting the ground at the tunnel face 33 with the rotating cutter 32.

[0023] In this embodiment, the rotary cutter 32 has a circular base 32a integrally joined to the tip of a rotary shaft 20b that extends from the housing 20a of the rotary joint 20, which is fixed to the center of the rear surface of the partition 35 in the excavation direction X, through the partition 35 and into the cutter chamber 31. This allows the rotary shaft 20b of the rotary joint 20 to rotate as the rotary cutter 32 rotates. In this embodiment, multiple cutting spokes 32b, each with a cutting bit 32c fixed thereto, are attached integrally to the circular base 32a of the rotary cutter 32, extending in all directions from the circular base 32a. A center bit 32d is attached integrally to the rotary cutter 32, protruding forward in the excavation direction X from the center where the circular base 32a is provided. In this embodiment, the supply port 32e for the fluidizing liquid material, which is a chemical solution, is provided at two locations: for example, at a location in the central part of the circular base portion 32a of the rotating cutter 32 that overlaps partially with the center bit 32d when viewed from the front side, and at a location in the tip portion of a selected cutting spoke 32b.

[0024] Furthermore, in this embodiment, the multiple cutting spokes 32b are provided with rotating and moving rods 32f, which extend rearward in the excavation direction X and are attached with their rear ends joined to an annular rotating rail member 46 of the rotary drive mechanism 45 (see FIG. 1). The annular rotating rail member 46 is engaged with the cutter drive device 34, preferably a hydraulic motor, fixed to the partition wall 35 inside the connection box 47, for example, via a gear mechanism. This allows the rotational drive force of the cutter drive device 34 to be transmitted to the cutting spokes 32b via the annular rotating rail member 46 and the rotating and moving rods 32f. This allows the rotary cutter 32 to rotate stably with a predetermined rotational torque, enabling the cutting bit 32c and center bit 32d to efficiently cut the ground at the excavation face 33.

[0025] In this embodiment, the rotary joint co-rotation detection mechanism 10 is provided as a mechanism for detecting when the fixed housing part 20a of the rotary joint 20 attached to the central part of the partition wall 35 that separates the cutter chamber 31 begins to co-rotate together with the rotation caused by the driving of the rotating cutter 32, as described above.As shown in Figures 3 to 5, a circumferential movement detectable part 11 having a predetermined circumferential detection width b (see Figure 5) is provided on the outer periphery of the tip part of the fixed housing part 20a of the rotary joint 20 in the excavation direction X, and a movement detector 12 that detects the circumferential movement of the circumferential movement detectable part 11 is attached, for example, via a support frame part 21 that extends rearward from the rear side surface of the partition wall 35 in the excavation direction X. The movement detector 12 detects that the circumferentially moving detected part 11 has moved circumferentially beyond a predetermined detection width b, thereby detecting that the fixed housing part 20a has begun to rotate together with the rotating cutter 32.

[0026] In this embodiment, as described above, the circumferential movement detectable portion 11 is preferably a contact protrusion 13 having a contact surface 13a at its tip, which protrudes radially outward and has a predetermined circumferential detection width b (see FIG. 5), provided on the outer periphery of the tip of the fixed housing portion 20a of the rotary joint 20 in the excavation direction X. That is, at the tip of the fixed housing portion 20a in the excavation direction X, a reinforcing annular flange portion 20c extending in the circumferential direction is attached integrally to the opening edge where the rotary shaft portion 20b rubs in the circumferential direction, and a fixed protrusion portion 20d (see FIGS. 6(a) and 6(b)) is provided projecting upward from the upper edge of the reinforcing annular flange portion 20c. A rectangular base metal member 20e (see FIGS. 6(a) and 6(b)) with a female screw hole formed therein is joined integrally to the surface of the fixed protrusion portion 20d on the rear side in the excavation direction X. By attaching a detectable metal part 15 (see Figures 7(a) and (b)) having a contact protrusion 13 to this base metal part 20e, the contact protrusion 13 as the circumferentially moving detectable part 11 is attached to the fixed housing part 20a with the contact surface part 13a facing upward (see Figures 4 and 5).

[0027] 7(a) and 7(b), the detectable metal fitting 15 has a trihedral shape formed by joining three metal plates, namely, a top plate 15a to which the contact protrusion 13 is joined, a side plate 15b, and a joining plate 15c, at their edges perpendicular to each other. The detectable metal fitting 15 is fixed to the fixed housing part 20a by aligning fastening holes provided in the joining plate 15c with female screw holes in the base metal fitting 20e and joining them with bolts, so that the top plate 15a is preferably positioned horizontally and the side plate 15b is positioned vertically with the contact protrusion 13 standing upright on the top surface of the tip part on the side away from the joining plate 15c (see FIGS. 4 and 5). As a result, the abutment protrusion 13 is arranged further rearward in the excavation direction X than the reinforcing annular flange portion 20c of the fixed housing portion 20a, and is positioned directly below the movement detector 12 described later with the abutment surface portion 13a facing upward.

[0028] In this embodiment, as shown in FIG. 8 , the contact protrusion 13 is a cylindrical metal member having a diameter of, for example, approximately 22 mm and a height of, for example, approximately 20 mm, and the peripheral portion of the lower end is chamfered in a tapered shape. The upper end surface forms the contact surface 13a, which is, for example, a flat or substantially flat and smooth surface. The contact surface 13a may also be a curved flat surface that is gently curved with a curvature radius of, for example, approximately 186 mm. The curved flat surface of the contact surface 13a allows the tip of the contact pin 14a of the limit switch 14 (described later) to more smoothly disengage from the contact surface 13a, making it possible to more accurately detect when the fixed housing part 20a begins to rotate together with the rotating cutter 32. If the abutment surface portion 13a has a diameter of, for example, approximately 22 mm, and the abutment pin 14a abuts the central portion of the abutment surface portion 13a, the abutment surface portion 13a will have a predetermined detection width b of, for example, 11 mm in the circumferential direction.

[0029] In this embodiment, the movement detector 12 is preferably a limit switch 14, as described above. The limit switch 14 is a known detector that can accurately detect movement of a sensing surface by having an abutment pin 14a, which protrudes while being biased from a device body 14b and can move back and forth, extend when released from a compressed state with its tip abutting against the sensing surface. In this embodiment, as shown in Figures 4 and 5, the detector mounting frame 17, to which the limit switch 14 is attached and fixed, is supported by a fixed bracket 16 that stands upright from the rear edge in the excavation direction X of the upper surface plate 21a of a support frame 21 that fixes the fixed housing portion 20a of the rotary joint 20 so that it does not rotate. The detector mounting frame 17 is connected and fixed, for example, by bolts, to a connecting surface 16a on the rear side of the excavation direction X of the fixed bracket 16. This makes it possible to position the limit switch 14 directly above the abutment protrusion 13, which is arranged rearward in the excavation direction X from the reinforcing annular flange portion 20c of the fixed housing portion 20a, with the abutment pin 14a positioned facing downward.

[0030] This also makes it possible to attach a movement detector 12 using a limit switch 14 with the tip of the abutment pin 14a abutting against the center of the abutment surface 13a of the abutment protrusion 13 located directly below, and to use the movement detector 12 using the limit switch 14 to accurately detect circumferential movement of the fixed housing part 20a of the rotary joint 20 due to co-rotation, for example, at a predetermined detection width b of 11 mm.

[0031] Furthermore, with the rotary joint co-rotation detection mechanism 10 of this embodiment having the above-mentioned configuration, when co-rotation occurs in the fixed housing portion 20a of the rotary joint 20 in conjunction with the rotation of the rotating cutter 32 due to, for example, clogging of the rotation support portion 40 that rotatably supports the rotating shaft portion 20b, which is attached facing the inside of the cutter chamber 31, due to, for example, excavated soil engaging with it, this can be detected immediately and reliably, and appropriate measures can be taken.

[0032] That is, according to this embodiment, a circumferential movement detectable part 11 is provided on the outer periphery of the tip of the fixed housing part 20a of the rotary joint 20 in the excavation direction X by the abutment surface part 13a of the abutment protrusion 13, which has a predetermined detection width b (see Figure 5), and a movement detector 12 is attached by a limit switch 14, for example, supported on the rear surface of the partition 35 in the excavation direction X, to detect the movement of the circumferential movement detectable part 11. Therefore, when the limit switch 14, preferably with the tip of its abutment pin 14a, moves out of contact with the abutment surface part 13a of the abutment protrusion 13, it becomes possible to reliably detect circumferential movement of the circumferential movement detectable part 11 beyond the predetermined detection width b, and it becomes possible to accurately and quickly detect when the fixed housing part 20a of the rotary joint 20 has started to rotate together with the rotating cutter 32, and after stopping the rotation of the rotating cutter 32 via, for example, a known interlock mechanism, appropriate measures can be smoothly taken.

[0033] The present invention is not limited to the above-described embodiment and various modifications are possible. For example, the circumferential movement detection portion does not necessarily have to be a cylindrical contact protrusion with a contact surface at its tip, and the movement detector does not necessarily have to be a limit switch. For example, various other well-known movement detection means such as an optical sensor, a breaking pin, or a proximity switch can also be used as the movement detector. The shield machine does not necessarily have to be a mud pressure type shield machine, and can be various other shield machines such as a mud water type shield machine.

[0034] 10 Rotary joint co-rotation detection mechanism 11 Circumferentially moving detected part 12 Movement detector 13 Contact protrusion 13a Contact surface part 14 Limit Switch 14a Contact pin 14b Device body 15 Detectable hardware 15a Top plate 15b Side plate 15c joint plate 16 Fixing bracket 17 Detector mounting frame 20 Rotary Joint 20a Fixed housing part 20b Rotating shaft 20c Reinforced annular flange 20d Fixed convex plate part 20e PCB hardware 21 Support frame part 21a Top plate 30 Mud pressure shield tunneling machine 31 Cutter chamber 32 Rotating cutter 33 Face 34 Cutter drive unit 35 Bulkhead 35a Insertion hole 36 Screw Conveyor 40 Rotation support part X Excavation direction b Predetermined detection width

Claims

1. A rotary joint co-rotation detection mechanism for a shield tunneling machine, which is attached to the center of a partition wall that divides a cutter chamber and sends various chemical solutions sent from the rear in the excavation direction to the rotating cutter, thereby enabling the chemical solutions to be supplied to the cutter chamber through piping inside the rotating cutter, detects when a fixed housing part of the rotary joint begins to rotate together with the rotating cutter, The rotary joint is attached to the partition wall with the fixed housing portion fixed to the rear central portion of the partition wall in the excavation direction, and the rotating shaft portion rotatably supported in an insertion hole provided in the partition wall and extending into the cutter chamber, and the rotating cutter is integrally joined to the tip portion of the rotating shaft portion in the excavation direction, a circumferentially moving detectable part having a predetermined detection width is provided on the outer periphery of the distal end of the fixed housing part of the rotary joint in the excavation direction, and a movement detector is attached that is supported on the rear surface of the partition in the excavation direction and detects movement of the circumferentially moving detectable part; A co-rotation detection mechanism for a rotary joint in which the movement detector detects that the circumferentially moving detectable portion has moved beyond the specified detection width, thereby detecting that the fixed housing portion of the rotary joint has begun to co-rotate with the rotating cutter.

2. The circumferential movement detection portion is a contact protrusion provided at a tip end thereof with a contact surface portion having a predetermined detection width, the contact surface portion being provided at a radially outwardly protruding outer periphery at a tip end portion of the fixed housing portion of the rotary joint in the excavation direction, The movement detector is a limit switch mounted in a state in which a tip of an abutment pin is in contact with the abutment surface of the abutment protrusion from the radial outside of the fixed housing part, 2. The co-rotation detection mechanism for a rotary joint as described in claim 1, which detects that the fixed housing part has started to rotate together with the rotating cutter when the tip of the abutment pin comes off the abutment surface of the abutment protrusion with which it was abutting.

3. 3. A co-rotation detection mechanism for a rotary joint according to claim 1 or 2, wherein the shield tunneling machine is a mud pressure type shield tunneling machine.

Images