Wear detection device and tunnel boring machine

Abstract

To provide a wear detection device and a tunnel boring machine that can be made less susceptible to effects of cutting heat, vibration, impact, etc.SOLUTION: A wear detection device 20 for a tunnel boring machine is a wear detection device for a tunnel boring machine which comprises a cylindrical boring machine body, a cutter head 11 rotatably mounted on a front end of the boring machine body, and a cutting tool (cutter bit 11e) mounted on a front face F1 of the cutter head 11, and comprises a rod 21b which can be extended from inside the cutter head 11 to a position forward of the front face F1 of the cutter head 11, and a processing device 24 which performs a wear amount detection process which extends the rod 21b to a position forward of the front face F1 of the cutter head 11, identifies the front-to-rear positions of the face 2 based on pressing force information which is information regarding the pressing force of the rod 21b and stroke amount information which is information regarding the stroke amount of the rod 21b, and calculates the amount of wear of the cutting tool based on the front-to-rear positions of the face 2.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a wear detection device and a tunnel boring machine. [Background technology]

[0002] Generally, a tunnel boring machine excavates a tunnel by rotating a cutter head to form a face in the ground ahead. The cutter head is attached to the front end of a cylindrical boring machine body, and the tunnel is excavated by propelling the boring machine body forward while rotating the cutter head.

[0003] Here, the cutting tool (e.g., cutter bit) attached to the front of the cutter head wears as the ground is excavated. It is desirable to excavate a tunnel while appropriately detecting the amount of wear on the cutting tool. For example, Patent Document 1 proposes a technology in which a member that wears as the cutting tool wears is provided inside the cutting tool, and the amount of wear on the cutting tool is detected based on the electrical resistance when electricity is passed through an electrical circuit formed in the member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-223311 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional techniques for detecting the amount of wear on a cutting tool, as in Patent Document 1, a device for detecting the amount of wear on a cutting tool is placed inside or near the cutting tool, and is therefore susceptible to the effects of cutting heat, vibration, impact, etc., and is therefore prone to failure. Note that, as a different method from Patent Document 1, there are also methods that use, for example, ultrasonic sensors or hydraulic sensors to detect deformation due to wear on a cutting tool, but in these methods as well, the device for detecting the amount of wear on a cutting tool is placed inside or near the cutting tool, and is therefore susceptible to the effects of cutting heat, vibration, impact, etc., and is therefore prone to failure.

[0006] In view of the above, an object of the present invention is to provide a wear detection device and a tunnel boring machine that can be made less susceptible to the effects of cutting heat, vibration, impact, etc. [Means for solving the problem]

[0007] In order to solve the above problems, the wear detection device of the present invention is a wear detection device for a tunnel boring machine which comprises a cylindrical boring machine body, a cutter head rotatably mounted on the front end of the boring machine body, and a cutting tool mounted on the front face of the cutter head, and comprises a rod which is extendable from inside the cutter head to a position forward of the front face of the cutter head, and a processing device which performs a wear amount detection process which extends the rod to a position forward of the front face of the cutter head, identifies the front and rear positions of the face based on pressing force information which is information regarding the pressing force of the rod and stroke amount information which is information regarding the stroke amount of the rod, and calculates the amount of wear of the cutting tool based on the front and rear positions of the face.

[0008] When the cutter head is rotating and tunnel excavation is being carried out, the processing device may retract the rod inside the cutter head, and perform the wear amount detection process when the cutter head is not rotating.

[0009] In the wear amount detection process, the processing device may continuously acquire pressing force information and stroke amount information as the rod extends, and identify the front and rear positions of the tip of the rod at the stroke amount at the time when the pressing force exceeds a threshold value based on the pressing force information and stroke amount information, and identify these front and rear positions as the front and rear positions of the face.

[0010] In the wear amount detection process, the processing device may calculate the distance between the front-to-rear position of the tip of the cutting tool in the initial state and the front-to-rear position of the cutting face as the wear amount of the cutting tool.

[0011] The longitudinal position of the tip of the rod at the maximum stroke amount may coincide with the longitudinal position of the tip of the cutting tool in the initial state, or may be located behind that longitudinal position.

[0012] The cutting tool may be a fixed cutting tool that is fixed relative to the cutter head.

[0013] The cutting tool may be a rotary cutting tool rotatably mounted on the cutter head.

[0014] The cutting tool may be an exchangeable cutting tool exchangeably attached to the cutter head.

[0015] An earth pressure gauge may be provided at the tip of the rod, and the processing device may obtain pressing force information based on the detection result of the earth pressure gauge.

[0016] A jack may be provided at the tip of the rod, and the processing device may obtain pressing force information based on information about the load of the jack.

[0017] In order to solve the above problem, a tunnel boring machine according to the present invention is provided with the above wear detection device. [Effects of the Invention]

[0018] According to the present invention, it is possible to provide a wear detection device and a tunnel boring machine that can be made less susceptible to the effects of cutting heat, vibration, impact, and the like. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a cross-sectional schematic diagram showing the overall configuration of a tunnel boring machine according to an embodiment of the present invention. FIG. [Figure 2] 1 is a schematic diagram showing a general configuration of a wear detection device according to an embodiment of the present invention; [Figure 3] FIG. 4 is a schematic diagram illustrating a state in the middle of extension of the wear detection device according to the embodiment of the present invention. [Figure 4] FIG. 4 is a schematic diagram illustrating a state in which the wear detection device according to the embodiment of the present invention has been fully extended. [Figure 5] 5 is a diagram showing an example of a transition of a pressing force of a rod of the wear detection device according to the embodiment of the present invention. FIG. [Figure 6] FIG. 10 is a schematic diagram showing a wear detection device according to a first modified example of the present invention. [Figure 7] FIG. 10 is a schematic diagram showing a wear detection device according to a second modified example of the present invention. [Figure 8] FIG. 10 is a schematic diagram showing a wear detection device according to a third modified example of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Dimensions, materials, and other specific values ​​shown in the embodiments are merely examples for facilitating understanding of the invention and, unless otherwise specified, do not limit the present invention. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0021] First, the overall configuration of a tunnel boring machine 1 according to an embodiment of the present invention will be described with reference to Figure 1. Figure 1 is a schematic cross-sectional view showing the overall configuration of the tunnel boring machine 1. Note that arrow A1 in Figure 1 indicates the traveling direction of the tunnel boring machine 1. Hereinafter, the traveling direction of the tunnel boring machine 1 (leftward in Figure 1) will also be referred to as the forward direction, and the direction opposite to the traveling direction (rightward in Figure 1) will also be referred to as the backward direction.

[0022] The tunnel boring machine 1 is an earth pressure type (including mud pressure type) shield boring machine capable of excavating natural ground. As shown in Figure 1, the tunnel boring machine 1 comprises an excavation machine main body 10. The excavation machine main body 10 is tubular (for example, cylindrical or rectangular tubular). The axial direction of the excavation machine main body 10 coincides with the tunnel excavation direction. Hereinafter, the axial direction of the excavation machine main body 10 will also be simply referred to as the axial direction, the radial direction of the excavation machine main body 10 will also be simply referred to as the radial direction, and the circumferential direction of the excavation machine main body 10 will also be simply referred to as the circumferential direction.

[0023] The excavator body 10 includes a skin plate 10a. The skin plate 10a is the part of the excavator body 10 that comes into contact with the inner wall surface (pit wall) of the natural ground formed by excavation by the tunnel boring machine 1. The skin plate 10a is tubular (for example, cylindrical or rectangular tubular) and forms the outer periphery of the excavator body 10.

[0024] A cutter head 11 is provided at the front end of the excavator body 10. The cutter head 11 is a roughly disk-shaped rotating body. The front end of a cutter central shaft 12 is fitted into the center of the cutter head 11, and the cutter head 11 is supported rotatably around the cutter central shaft 12.

[0025] The cutter head 11 includes an outer ring 11a, an inner ring 11b, cutter spokes 11c, a fishtail cutter 11d, and a cutter bit 11e. Of these, the outer ring 11a forms the outer periphery of the cutter head 11, and the inner ring 11b is disposed radially inward of the outer ring 11a. Furthermore, multiple cutter spokes 11c are disposed radially around the cutter central axis 12 on the front surface of the cutter head 11. A fishtail cutter 11d is attached to the center of the front surface of the cutter head 11. Furthermore, multiple cutter bits 11e are attached to the front surfaces of the cutter spokes 11c. The fishtail cutter 11d and the cutter bit 11e may or may not be detachable.

[0026] A plurality of openings are formed between the outer circumferential ring 11a, the inner circumferential ring 11b, and the cutter spokes 11c in the cutter head 11. The openings function as excavated soil intake ports for taking excavated soil generated when the cutter head 11 excavates the natural ground (face) into the excavator body 10 (into a chamber 17 described later).

[0027] A partition wall 13 is arranged behind the cutter head 11 on the excavator body 10. The partition wall 13 is a plate-shaped (for example, disc-shaped) wall arranged perpendicular to the axial direction (tunnel extension direction), and the outer edge of the partition wall 13 is attached to the inner peripheral surface of the excavator body 10. The cutter head 11 and the partition wall 13 are arranged at a predetermined distance in the axial direction (tunnel extension direction). Various pieces of equipment for the tunnel boring machine 1 are arranged behind the partition wall 13, and the partition wall 13 isolates the equipment from the excavated soil generated at the face. A discharge port 13a, which is an opening for discharging the excavated soil, is formed in the lower part of the partition wall 13.

[0028] A cutter central shaft 12 is rotatably supported at the center of the partition wall 13. Furthermore, an annular rotating ring 14 is supported on the partition wall 13 so as to be rotatable around the cutter central shaft 12. A plurality of connecting beams 15 are provided at a predetermined interval in the circumferential direction at the front of the rotating ring 14. The plurality of connecting beams 15 connect the cutter head 11 and the rotating ring 14. The front ends of the connecting beams 15 are connected to the connection between the inner ring 11b of the cutter head 11 and the cutter spokes 11c. Meanwhile, a ring gear 14a is provided at the rear of the rotating ring 14. The ring gear 14a may be either an externally toothed type or an internally toothed type. Furthermore, a cutter rotation motor 16 is provided behind the partition wall 13. A drive gear 16a of this cutter rotation motor 16 meshes with the ring gear 14a of the rotating ring 14.

[0029] By driving the cutter rotation motor 16, the rotation of the drive gear 16a is transmitted from the ring gear 14a to the rotating ring 14 and the connecting beam 15. This allows the cutter head 11 to rotate around the cutter central axis 12. As a result, the front face of the rotating cutter head 11 is pressed against the natural ground (face), allowing the natural ground to be excavated. In Figure 1, the face 2, which is the surface excavated by the cutter head 11, is shown by a dashed line.

[0030] A chamber 17 is defined between the cutter head 11 and the partition wall 13. The chamber 17 is a space (for example, a substantially cylindrical space) defined by the rear surface of the cutter head 11, the front surface of the partition wall 13, and the inner peripheral surface of the excavator body 10. Excavated earth and sand generated when the cutter head 11 excavates the natural ground is taken into the chamber 17 through the opening (excavated earth and sand intake port) formed through the cutter head 11. The chamber 17 functions as a space (room) for temporarily storing the excavated earth and sand. The excavated earth and sand taken into the chamber 17 is discharged from the chamber 17 into the screw conveyor 18 through the discharge port 13a at the bottom of the partition wall 13.

[0031] The screw conveyor 18 is provided on the rear side of the partition wall 13 inside the excavator body 10. The screw conveyor 18 is arranged inside the excavator body 10 so that it slopes upward as it moves toward the rear. The opening at the front end of the screw conveyor 18 is connected to the discharge port 13a of the partition wall 13. As a result, the internal space of the screw conveyor 18 communicates with the chamber 17 through the discharge port 13a of the partition wall 13. The screw conveyor 18 is provided with a screw blade 18a, which is a screw-shaped rotating body with helical blades. By driving the screw blade 18a to rotate, the excavated soil stored in the chamber 17 can be taken into the screw conveyor 18, transported toward the rear of the excavator body 10, and discharged.

[0032] An erector device (not shown) is provided on the rear side of the partition wall 13 of the excavator body 10. The erector device is provided so as to be movable in the axial, radial and circumferential directions (i.e., the tunnel extension direction, the tunnel radial direction and the tunnel circumferential direction) of the excavator body 10. The erector device is capable of gripping the segments S, which are lining members, and assembles the gripped segments S along the inner wall surface of the natural ground.

[0033] The segments S are ring pieces with a curved shape that follows the inner wall surface of the excavated natural ground. By driving the erector device, multiple segments S can be assembled in a ring shape along the circumferential direction. This allows the tunnel to be lined with multiple segments S, preventing the inner wall surface of the natural ground from collapsing.

[0034] A plurality of shield jacks 19 are provided within the excavator body 10 at intervals from one another in the circumferential direction. Each shield jack 19 is provided so as to extend in the tunnel extension direction along the inner circumferential surface of the excavator body 10. The shield jack 19 is, for example, a hydraulic jack, but other types of jacks, actuators, etc. may be used as long as they are capable of generating thrust for the tunnel boring machine 1. An extendable drive rod 19a is provided at the rear end of each shield jack 19. The tip of the drive rod 19a faces the front end face of the existing segment S. By extending the drive rod 19a of the shield jack 19 rearward and pressing against the segment S, a thrust reaction force (i.e., thrust) can be applied to the excavator body 10. In other words, the thrust generated when the shield jack 19 presses against the segment S enables the excavator body 10 to move forward.

[0035] It should be noted that while the tunnel boring machine 1 shown in FIG. 1 is a type in which thrust is transmitted from the front end of the shield jack 19 to the boring machine main body 10, the tunnel boring machine according to the present invention is not limited to this example. For example, the tunnel boring machine according to the present invention may be a type in which thrust is transmitted from the rear portion of the shield jack 19 to the boring machine main body 10. It should be noted that the tunnel boring machine according to the present invention may be a type in which the tunnel boring machine has a bending function and is propelled by pushing the front body, or a type in which the tunnel boring function and is propelled by pushing the rear body. Furthermore, the tunnel boring machine according to the present invention may be a tunnel boring machine in which the drive system for the cutter head 11 is a system other than the intermediate support system shown in FIG. 1 (for example, a center shaft system, a central axle support system, or a peripheral support system).

[0036] The tunnel boring machine 1 is equipped with a wear detection device (see wear detection device 20 in FIG. 2 etc. described later) for detecting the amount of wear on the cutting tool provided on the front surface of the cutter head 11. In this embodiment, by implementing improvements to the wear detection device, it is possible to make the wear detection device less susceptible to the effects of cutting heat, vibrations, shocks, etc., as will be described later. The wear detection device will be described in detail below with reference to FIGS. 2 to 5.

[0037] 2 is a schematic diagram showing the overall configuration of the wear detection device 20. The wear detection device 20 is provided to detect the amount of wear of the cutter bit 11e, which is a cutting tool provided on the front surface F1 of the cutter head 11. However, as will be described later, the cutting tool whose amount of wear is to be detected is not limited to the cutter bit 11e. Note that, for example, a plurality of wear detection devices 20 may be provided at intervals in the radial direction on the cutter head 11. However, the number and arrangement of the wear detection devices 20 are not particularly limited.

[0038] 2 shows a cross section perpendicular to the axial direction of the cutter spoke 11c. As shown in FIG. 2, the cutter spoke 11c is formed, for example, in the shape of a hollow cylinder having a substantially trapezoidal cross section. A pair of cutter bits 11e is provided at both ends in the width direction (the vertical direction in FIG. 2) of a front plate portion 11c1 of the cutter spoke 11c, which is a flat-plate-shaped portion that forms the front surface F1 of the cutter head 11. The cutter bits 11e protrude forward beyond the front surface F1 of the cutter head 11.

[0039] As shown in FIG. 2, the wear detection device 20 includes a jack 21, a pressing force detection sensor 22, a stroke sensor 23, and a processing device 24.

[0040] The jack 21 is, for example, a hydraulic jack. However, the driving system of the jack 21 is not limited to hydraulic, and may be pneumatic or electric. The jack 21 has a main body 21a and a rod 21b.

[0041] The main body 21a is a cylindrical member that extends in the front-to-rear direction of the tunnel boring machine 1. The main body 21a is disposed inside the cutter spokes 11c and attached to the back surface of the front plate portion 11c1 of the cutter spokes 11c.

[0042] The rod 21b is disposed coaxially with the main body 21a and is inserted inside the main body 21a. The rod 21b protrudes forward from the front end of the main body 21a. The rod 21b is slidable relative to the main body 21a. The rod 21b is extendable by sliding in the front-to-rear direction relative to the main body 21a. Here, the rod 21b is inserted through a through-hole 11c2 provided in the front plate portion 11c1 of the cutter spoke 11c. The through-hole 11c2 penetrates the front plate portion 11c1 in the front-to-rear direction.

[0043] In the state shown in FIG. 2, the front-to-rear position of the tip of rod 21b coincides with the front-to-rear position of the front surface F1 of cutter head 11. In other words, rod 21b does not extend forward of the front surface F1 of cutter head 11, but is retracted inside the cutter head 11. The interior of cutter head 11 refers to the space located behind the front surface F1 of cutter head 11 and surrounded by the members that make up cutter head 11. Note that the description of rod 21b being retracted inside cutter head 11 may also include a case where a part (specifically, most of) rod 21b is housed inside cutter head 11, and another part of rod 21b protrudes outside cutter head 11.

[0044] Here, the rod 21b can extend from inside the cutter head 11 to a position forward of the front surface F1 of the cutter head 11. As will be described later, when the cutter head 11 is rotating and tunnel excavation is being performed, the rod 21b retreats inside the cutter head 11 and assumes the state shown in FIG. 2. On the other hand, when the cutter head 11 is not rotating and a wear amount detection process is performed to detect the wear amount of the cutter bit 11e, the rod 21b extends to a position forward of the front surface F1 of the cutter head 11 as shown in FIG. 3.

[0045] The pressing force detection sensor 22 is a sensor for detecting the pressing force of the rod 21b, which is the force with which the tip of the rod 21b presses against a surrounding object. For example, if the jack 21 is a hydraulic jack, the pressing force detection sensor 22 is a hydraulic sensor provided inside the jack 21 and detects the hydraulic pressure inside the jack 21. In this case, the rod 21b operates due to the hydraulic pressure inside the jack 21. The hydraulic pressure inside the jack 21 correlates with the pressing force of the rod 21b, which is the force with which the tip of the rod 21b presses against a surrounding object. Note that various known methods can be applied as a method for detecting hydraulic pressure using a hydraulic sensor used as the pressing force detection sensor 22.

[0046] The sensor used as pressing force detection sensor 22 differs depending on the drive system of jack 21. For example, if jack 21 is driven by a pneumatic system, an air pressure sensor that detects the air pressure acting on rod 21b is used as pressing force detection sensor 22. If jack 21 is driven by an electric system, a current sensor that detects the current applied to drive rod 21b is used as pressing force detection sensor 22. Note that various known methods can be used as a detection method for the air pressure sensor or current sensor used as pressing force detection sensor 22.

[0047] The stroke sensor 23 is provided inside the jack 21 and detects the stroke amount of the rod 21b (see stroke amount ST in FIG. 3 and the like described later). As shown in FIG. 3 and the like described later, the stroke amount ST of the rod 21b corresponds to, for example, the distance in the front-rear direction between the tip of the rod 21b and the front face F1 of the cutter head 11. Note that various known methods can be used as a method for detecting the stroke amount ST by the stroke sensor 23.

[0048] For example, if the drive system of the jack 21 is hydraulic, the stroke sensor 23 may be a length measuring sensor that directly measures the amount of movement of the rod 21b of the jack 21, or it may be an oil volume measuring sensor that detects the amount of oil flowing in and out due to the extension and contraction movement of the jack 21 and determines the stroke value based on this.

[0049] The processing device 24 includes a CPU (Central Processing Unit), which is an arithmetic processing device, a ROM (Read Only Memory), which is a memory element that stores programs and calculation parameters used by the CPU, and a RAM (Random Access Memory), which is a memory element that temporarily stores parameters that change appropriately during CPU execution.

[0050] The processing device 24 controls the operation of the jack 21. For example, the processing device 24 controls the hydraulic pressure inside the jack 21 to extend and retract the rod 21b of the jack 21, thereby controlling the stroke amount ST of the rod 21b. The processing device 24 can also acquire the detection results of the pressing force detection sensor 22 and the stroke sensor 23.

[0051] Here, the processing device 24 performs a wear amount detection process, which is a process for detecting the amount of wear on the cutter bit 11e. Specifically, when the cutter head 11 is rotating and excavating a tunnel, the processing device 24 retracts the rod 21b inside the cutter head 11, and performs the wear amount detection process when the cutter head 11 is not rotating. In the wear amount detection process, the processing device 24 extends the rod 21b forward of the front surface F1 of the cutter head 11, and calculates the amount of wear on the cutter bit 11e using the detection results of each sensor at that time. Hereinafter, the manner in which the rod 21b is extended in the wear amount detection process will be described with reference to FIGS. 3 and 4.

[0052] Fig. 3 is a schematic diagram showing a state in the middle of extension of the wear detection device 20. When the wear amount detection process starts, the processing device 24 extends the rod 21b, which has been retracted inside the cutter head 11, forward. As a result, as shown in Fig. 3, the tip of the rod 21b is positioned forward of the front surface F1 of the cutter head 11. The state in Fig. 3 corresponds to a state in the middle of extension in which the rod 21b is in the middle of extension during the wear amount detection process.

[0053] FIG. 4 is a schematic diagram showing the wear detection device 20 in a state where extension is complete. During the wear amount detection process, as the rod 21b extends, the tip of the rod 21b gradually moves forward toward the working face 2. Then, as shown in FIG. 4, when the tip of the rod 21b reaches the working face 2, the extension force of the rod 21b increases significantly. The working face 2 is formed of harder soil and sand than the excavated and loosened soil and sand between the front face F1 of the cutter head 11 and the working face 2. The upper limit of the pressing force of the rod 21b is not high enough to allow the rod 21b to penetrate into the working face 2. Therefore, after the tip of the rod 21b reaches the working face 2, the extension force increases significantly as the rod 21b extends further forward.

[0054] The processing device 24 calculates the amount of wear of the cutter bit 11e based on pressing force information, which is information regarding the pressing force of the rod 21b, and stroke amount information, which is information regarding the stroke amount ST of the rod 21b during the process of the rod 21b extending as described above.

[0055] Here, the pressing force information may be, for example, information that directly indicates the pressing force of rod 21b, or other information that can be substantially converted into the pressing force of rod 21b (for example, information that indicates the detection result itself of pressing force detection sensor 22, etc.) The processing device 24 can acquire, for example, information that directly indicates the pressing force of rod 21b based on the detection result of pressing force detection sensor 22 as pressing force information.

[0056] Furthermore, the stroke amount information may be, for example, information that directly indicates the stroke amount ST, or other information that can be substantially converted into the stroke amount ST (for example, information detected by the stroke sensor 23 before being converted into the stroke amount ST). The processing device 24 can acquire, for example, information that directly indicates the stroke amount ST as the stroke amount information based on the detection result of the stroke sensor 23.

[0057] Fig. 5 is a diagram showing an example of the transition of the pressing force of rod 21b of wear detection device 20. In the example of Fig. 5, rod 21b starts to extend at time T1. Then, at time T2, the tip of rod 21b reaches the working face 2, and the pressing force of rod 21b increases significantly.

[0058] In the wear amount detection process, first, the processing device 24 identifies the front and rear positions of the cutting face 2 based on the pressing force information and stroke amount information when the rod 21b is extended forward of the front face F1 of the cutter head 11.

[0059] Specifically, the processing device 24 continuously acquires pressing force information and stroke amount information as the rod 21b extends. This allows the processing device 24 to acquire information indicating the transition of the pressing force of the rod 21b, for example, as shown in FIG. 5. During the period (from time T1 to time T2) in which the rod 21b extends the excavated space between the front surface F1 of the cutter head 11 and the working face 2, the pressing force of the rod 21b remains at a value smaller than the threshold value TH. During this time, the pressing force of the rod 21b increases and decreases slightly to push aside the excavated earth and sand present in the excavated space. Then, at time T2, when the tip of the rod 21b abuts against the working face 2, the pressing force of the rod 21b suddenly increases and exceeds the threshold value TH.

[0060] Here, the processing device 24 identifies the longitudinal position of the tip of the rod 21b at the stroke amount ST at the time when the pressing force exceeds the threshold value TH, based on the pressing force information and the stroke amount information. For example, in the example of Fig. 5, at time T2 when the tip of the rod 21b reaches the working face 2, the pressing force suddenly increases and exceeds the threshold value TH. Therefore, the processing device 24 identifies the longitudinal position of the tip of the rod 21b at the stroke amount ST at time T2 (for example, the longitudinal position of the tip of the rod 21b in Fig. 4).

[0061] The processing device 24 specifies the longitudinal position of the tip of the rod 21b specified as above (for example, the longitudinal position of the tip of the rod 21b in FIG. 4) as the longitudinal position of the cutting face 2. Then, the processing device 24 calculates the distance between the longitudinal position of the tip of the cutter bit 11e in the initial state and the longitudinal position of the cutting face 2 as the amount of wear of the cutter bit 11e.

[0062] For example, in FIG. 4, the outline of the cutter bit 11e in the initial state is indicated by a two-dot chain line. In the initial state, the tip of the cutter bit 11e is not worn, and therefore the tip of the cutter bit 11e is positioned forward relative to the current tip of the cutter bit 11e, which is indicated by a solid line. In the example of FIG. 4, the processing device 24 calculates the distance D1 between the front-rear position of the tip of the cutter bit 11e in the initial state, indicated by a two-dot chain line, and the front-rear position of the cutting face 2 as the wear amount of the cutter bit 11e. As shown in FIG. 4, the cutting face 2 is the surface excavated by the tip of the cutter bit 11e. Therefore, the front-rear position of the cutting face 2 coincides with the front-rear position of the current tip of the cutter bit 11e. Therefore, the distance D1 between the front-rear position of the tip of the cutter bit 11e in the initial state and the front-rear position of the cutting face 2 corresponds to the wear amount of the cutter bit 11e from the initial state to the present.

[0063] As described above, the wear detection device 20 according to this embodiment includes the rod 21b, which can be extended from inside the cutter head 11 to a position forward of the front surface F1 of the cutter head 11, and the processing device 24. The processing device 24 extends the rod 21b to a position forward of the front surface F1 of the cutter head 11, identifies the longitudinal position of the cutting face 2 based on pressing force information, which is information related to the pressing force of the rod 21b, and stroke amount information, which is information related to the stroke amount ST of the rod 21b, and performs a wear amount detection process to calculate the wear amount of the cutting tool (in the above example, the cutter bit 11e) based on the longitudinal position of the cutting face 2. This allows the device for detecting the wear amount (e.g., the jack 21) of the wear detection device 20 to be located at a position separated from the cutting tool, rather than being located within or near the cutting tool. This makes the wear detection device 20 less susceptible to the effects of cutting heat, vibration, impact, and the like from the cutting tool, thereby preventing breakdowns of the wear detection device 20.

[0064] As described above, specifically, in the wear amount detection process, the processing device 24 continuously acquires pressing force information and stroke amount information as the rod 21b extends, and identifies the front-rear position of the tip of the rod 21b at the stroke amount ST at the time when the pressing force exceeds the threshold value TH based on the pressing force information and stroke amount information, and identifies the front-rear position as the front-rear position of the working face 2. This makes it possible to appropriately calculate the wear amount of the cutting tool (in the above example, the cutter bit 11e).

[0065] The method for identifying the front and rear positions of the face 2 is not limited to the above example. For example, the processing device 24 may identify the front and rear positions of the tip of the rod 21b at the stroke amount ST at the time when the amount of change over time of the pressing force exceeds a predetermined value as the front and rear positions of the face 2. This also makes it possible to identify the time when the tip of the rod 21b reaches the face 2, and therefore the front and rear positions of the face 2.

[0066] As described above, specifically, in the wear amount detection process, the processing device 24 calculates the distance (distance D1 in FIG. 4 in the above example) between the front-rear position of the tip of the cutting tool (cutter bit 11e in the above example) in the initial state and the front-rear position of the cutting face 2 as the wear amount of the cutting tool. This allows the wear amount of the cutting tool to be calculated appropriately.

[0067] The method for calculating the amount of wear of the cutting tool is not limited to the above example. For example, in the wear amount detection process, the processing device 24 may calculate the amount of wear of the cutting tool by multiplying the distance between the front-rear position of the tip of the cutting tool in the initial state and the front-rear position of the working face 2 (distance D1 in FIG. 4 in the above example) by a predetermined correction coefficient. This makes it possible to calculate the amount of wear of the cutting tool, taking into account, for example, a determination error in the front-rear position of the working face 2.

[0068] Here, it is preferable that the longitudinal position of the tip of the rod 21b at the maximum stroke amount ST coincides with the longitudinal position of the tip of the cutting tool (in the above example, the cutter bit 11e) in the initial state, or is located rearward of that longitudinal position. As described above, the working face 2 is the surface excavated by the tip of the cutter bit 11e. Therefore, by setting the maximum stroke amount ST of the rod 21b as described above, the tip of the rod 21b can be made to reach the working face 2, and the wear amount of the cutting tool can be calculated by the wear amount detection process. Therefore, by setting the maximum stroke amount ST of the rod 21b as described above, it is possible to appropriately perform the wear amount detection process while preventing the maximum stroke amount ST from becoming longer than necessary.

[0069] In the above example, the cutting tool is a fixed cutting tool (the cutter bit 11e in the above example) fixed to the cutter head 11. Therefore, the wear detection device 20 can detect the wear amount of the fixed cutting tool while being less susceptible to the effects of cutting heat, vibration, impact, and the like. However, the cutting tool whose wear amount is to be detected is not limited to the cutter bit 11e. This also applies to the wear detection devices 20B and 20C described below. For example, the cutting tool whose wear amount is to be detected may be any fixed cutting tool that differs in shape, arrangement, purpose, etc. from the cutter bit 11e. Furthermore, the cutting tool whose wear amount is to be detected may be a movable cutting tool (e.g., expandable in the front-rear direction). Note that there are also movable cutting tools whose front-rear position is adjusted according to the progress of wear and the excavated soil quality. However, since the wear detection device 20 is installed separately from the cutting tool, it is also effective to apply the wear detection device 20 to such movable cutting tools. Furthermore, the cutting tool whose wear amount is to be detected may be an exchangeable cutting tool that is exchangeably attached to the cutter head 11. If the cutting tool is replaceable, it can be replaced without modifying the wear detection device 20. As will be described later, the cutting tool whose wear amount is to be detected may be a rotary cutting tool.

[0070] Various modifications of the wear detection device 20 described above will be described below in order with reference to FIGS.

[0071] 6 is a schematic diagram showing a wear detection device 20A according to a first modified example of the present invention. The wear detection device 20A according to the first modified example is different from the above-described wear detection device 20 in that the cutting tool that is the object of wear detection is different. In other respects, it is the same as the above-described wear detection device 20.

[0072] As shown in Fig. 6, the wear detection device 20A, like the above-described wear detection device 20, includes a jack 21, a pressing force detection sensor 22, a stroke sensor 23, and a processing device 24. Similarly to Fig. 2, Fig. 6 shows a cross section perpendicular to the axial direction of the cutter spoke 11c. In the example of Fig. 6, a disc cutter 11f, which is a rotary cutting tool, is rotatably attached to the front side of the cutter spoke 11c. The disc cutter 11f corresponds to the cutting tool whose wear amount is to be detected by the wear detection device 20A.

[0073] The disc cutter 11f can rotate, for example, around a rotation axis C1 that is parallel to the central axis of the cutter spokes 11c. The rotation axis C1 of the disc cutter 11f is located inside the cutter head 11. Meanwhile, a part of the disc cutter 11f protrudes forward beyond the front surface F1 of the cutter head 11. The part of the disc cutter 11f that protrudes forward beyond the front surface F1 of the cutter head 11 excavates the natural ground, forming the working face 2.

[0074] The wear amount detection process performed by the processing device 24 is the same as that of the above-described wear detection device 20, and therefore a description thereof will be omitted. In the wear detection device 20A, the wear amount detection process performed by the processing device 24 detects the wear amount of the disc cutter 11f.

[0075] As described above, in the wear detection device 20A according to the first modification, the cutting tool is a rotary cutting tool (in the above example, a disc cutter 11f) rotatably attached to the cutter head 11. Therefore, the wear detection device 20A can detect the wear amount of the rotary cutting tool while being resistant to the effects of cutting heat, vibration, and impact. Even when uneven wear occurs on the rotary cutting tool, the wear amount can be detected regardless of the rotation angle of the cutting tool, allowing the wear amount to be detected without being affected by uneven wear. For example, if the rotary cutting tool is functioning properly, the wear state can be determined as uniform wear. Even when uneven wear occurs due to the rotary cutting tool sticking (stopping rotation), the wear amount of the cutting tool toward the cutting face 2 (in the direction relative to the cutting face 2) can be detected by detecting the cutting face 2 formed by the cutting tool, allowing the user to determine whether there is a problem with the excavation function. However, the cutting tool to be subjected to the detection of the wear amount may be any rotary cutting tool that is different in shape, arrangement, use, etc. from the disc cutter 11f.

[0076] 7 is a schematic diagram showing a wear detection device 20B according to a second modified example of the present invention. The wear detection device 20B according to the second modified example differs from the above-described wear detection device 20 in that it additionally includes an earth pressure meter 31. In other respects, it is the same as the above-described wear detection device 20.

[0077] 7, the wear detection device 20B, like the above-described wear detection device 20, includes a jack 21, a pressing force detection sensor 22, a stroke sensor 23, and a processing device 24. Here, the wear detection device 20B further includes an earth pressure meter 31.

[0078] The earth pressure meter 31 is provided at the tip of the rod 21b of the jack 21, and detects the earth pressure acting on the tip of the rod 21b. The earth pressure acting on the tip of the rod 21b correlates with the pressing force of the rod 21b. Note that various known methods can be applied to the method of detecting earth pressure using the earth pressure meter 31.

[0079] The wear amount detection process performed by the processing device 24 is basically the same as that of the above-described wear detection device 20, so a detailed description will be omitted. However, unlike the above-described wear detection device 20, in the wear detection device 20B, the processing device 24 acquires pressing force information based on the detection result of the earth pressure meter 31 during the wear amount detection process. For example, the processing device 24 can acquire information directly indicating the pressing force of the rod 21b as pressing force information based on the detection result of the earth pressure meter 31. Note that other processes in the wear amount detection process are the same as those in the above-described wear detection device 20.

[0080] As described above, in the wear detection device 20B according to the second modification, the earth pressure meter 31 is provided at the tip of the rod 21b. The processing device 24 acquires pressing force information based on the detection result of the earth pressure meter 31. The detection result of the pressing force detection sensor 22 not only varies depending on the pressing force of the rod 21b, but may also vary depending on other forces, such as frictional resistance between components within the jack 21. On the other hand, the detection result of the earth pressure meter 31 is not affected by frictional resistance between components within the jack 21. Therefore, by acquiring pressing force information based on the detection result of the earth pressure meter 31, it is possible to acquire pressing force information with higher accuracy than when, for example, pressing force information is acquired based on the detection result of the pressing force detection sensor 22. As a result, the amount of wear of the cutting tool (in the above example, the cutter bit 11e) can be detected with higher accuracy. Furthermore, since the earth pressure meter 31 measures the earth pressure acting on the tip (front surface F1) of the rod 21b when the jack 21 is retracted (such as when excavating the ground by rotating the cutter), this makes it possible to instantly grasp changes in earth pressure near the tip of the rod 21b when the rod 21b is extended, and it is also possible to determine whether the pressing force until the rod 21b hits the face when extended is appropriate, allowing for more reliable (advanced) operation of the wear detection device 20B. This is considered to be effective, for example, when excavating soft ground, where the difference in pressing force between the face 2 (unduged ground) and the cut, loosened earth and sand (earth and sand between the front surface F1 and the face 2) is thought to be small.

[0081] 8 is a schematic diagram showing a wear detection device 20C according to a third modified example of the present invention. The wear detection device 20C according to the third modified example differs from the above-described wear detection device 20 in that a jack 32 is added to the tip of the rod 21b. In other respects, it is the same as the above-described wear detection device 20.

[0082] Fig. 8 shows an enlarged view of the tip of the rod 21b of the jack 21 in the wear detection device 20C. As shown in Fig. 8, in the wear detection device 20C, a jack 32 is provided at the tip of the rod 21b of the jack 21. Note that, although an example of the internal structure of the jack 32 will be described below with reference to Fig. 8, the example in Fig. 8 is merely one example of the jack 32.

[0083] The jack 32 is, for example, a hydraulic jack. However, the drive system of the jack 32 is not limited to hydraulic, and may be pneumatic or electric. The jack 32 has a housing 32a, a piston 32b, and a rod 32c.

[0084] Housing 32a is a cylindrical member that extends in the front-to-rear direction of tunnel boring machine 1. Housing 32a is attached to the tip of rod 21b of jack 21 and is arranged coaxially with rod 21b. The front part of housing 32a forms part of the tip surface of rod 21b. Housing 32a may be attached to rod 21b by, for example, screwing or welding.

[0085] The piston 32b has a cylindrical shape. The piston 32b is arranged coaxially with the housing 32a and slides in the front-to-rear direction within the housing 32a. The outer circumferential surface of the piston 32b contacts the inner circumferential surface of the housing 32a. The internal space of the housing 32a is divided into front and rear sections by the piston 32b.

[0086] The rod 32c has a cylindrical shape. The outer diameter of the rod 32c is smaller than the outer diameter of the piston 32b. The rod 32c is attached to the front surface of the piston 32b and is arranged coaxially with the piston 32b. The rod 32c is inserted into a through-hole 32a1 provided in the front part of the housing 32a. The through-hole 32a1 is arranged on the central axis of the housing 32a and connects the inside and outside of the housing 32a. The tip of the rod 32c is located outside the housing 32a and protrudes further forward than the tip of the rod 21b of the jack 21. The rod 32c moves integrally with the piston 32b.

[0087] The internal space of the housing 32a is an oil chamber filled with hydraulic oil. A port P1 connected to an oil passage is formed in a portion of the internal space of the housing 32a rearward of the piston 32b. When hydraulic oil is supplied to a portion of the internal space of the housing 32a rearward of the piston 32b through the port P1, the piston 32b and the rod 32c move forward. A port P2 connected to an oil passage is formed in a portion of the internal space of the housing 32a forward of the piston 32b. When hydraulic oil is supplied to a portion of the internal space of the housing 32a forward of the piston 32b through the port P2, the piston 32b and the rod 32c move rearward.

[0088] Here, the wear detection device 20C further includes a hydraulic sensor 33. The hydraulic sensor 33 is provided, for example, in the rod 21b of the jack 21, and detects the hydraulic pressure acting on the jack 32. The hydraulic pressure acting on the jack 32 corresponds to an example of information about the load on the jack 32. Note that various known methods can be applied as a method for detecting the hydraulic pressure using the hydraulic sensor 33. The load on the jack 32 is correlated with the pressing force of the rod 21b. Therefore, the processing device 24 can obtain pressing force information based on the detection result of the hydraulic sensor 33. Note that if the jack 32 is not hydraulic, the hydraulic sensor 33 is equipped with a pressing force detection sensor that corresponds to the drive method (pneumatic or electric).

[0089] The wear amount detection process performed by the processing device 24 is basically the same as that of the above-described wear detection device 20, so a detailed description will be omitted. Here, in the wear detection device 20C, the processing device 24 basically acquires pressing force information based on the detection results of the pressing force detection sensor 22, as in the above-described wear detection device 20. However, in the wear detection device 20C, when finally specifying the front and rear positions of the working face 2 in the wear amount detection process, the processing device 24 acquires pressing force information based on information about the load of the jack 32.

[0090] For example, the processing device 24 determines whether the tip of the rod 21b has reached the vicinity of the working face 2 based on the transition of the pressing force of the rod 21b obtained using the pressing force detection sensor 22. When the processing device 24 determines that the tip of the rod 21b has reached the vicinity of the working face 2, it acquires pressing force information based on the detection result of the hydraulic sensor 33 of the jack 32 in the extended state (i.e., information about the load on the jack 32). Then, based on the pressing force information and the stroke amount information, the processing device 24 identifies the front-rear position of the tip of the rod 21b at the stroke amount ST at the time when the pressing force obtained from the load on the jack 32 exceeds the threshold value TH, and identifies the front-rear position as the front-rear position of the working face 2. Note that other processes in the wear amount detection process are similar to those of the wear detection device 20 described above.

[0091] In the process of identifying the front and rear positions of the working face 2 in association with the extension of the jacks 21 and 32, various modes can be considered for the relationship between the extension timing of the jacks 21 and 32 (for example, a mode in which the extension of the jacks 21 finishes first and then starts, a mode in which the extension of the jacks 21 and 32 is performed in parallel or alternately, or a mode in which the extension of the jacks 32 finishes first and then starts). In any mode, it is possible to obtain pressing force information using the detection result of the hydraulic sensor 33 when the jack 32 abuts against the working face 2.

[0092] As described above, in the wear detection device 20C according to the third modification, the jack 32 is provided at the tip of the rod 21b. The processing device 24 acquires pressing force information based on information about the load of the jack 32. As described above, the detection result of the pressing force detection sensor 22 varies not only depending on the pressing force of the rod 21b but also depending on other forces, such as frictional resistance between components within the jack 21. On the other hand, although the load of the jack 32 is affected by frictional resistance between components within the jack 32, it has a stronger correlation with the actual pressing force of the rod 21b against the excavated earth or the working face 2 than the detection result of the pressing force detection sensor 22. Therefore, by acquiring pressing force information based on the load of the jack 32, it is possible to acquire pressing force information with higher accuracy than, for example, when the pressing force information is acquired based on the detection result of the pressing force detection sensor 22. As a result, the amount of wear of the cutting tool (in the above example, the cutter bit 11e) can be detected with higher accuracy. For example, by extending the jack 32 once and detecting the load (pushing force) before extending the rod 21b of the jack 21, the state of the excavated soil near the front face F1 can be accurately grasped. This makes it possible to determine whether the pushing force until the rod 21b hits the face when extended is appropriate, allowing for more reliable (advanced) operation of the wear detection device 20C. For example, this is considered effective in cases where the difference in pushing force between the face 2 (unduged ground) and the loosened soil (soil between the front face F1 and the face 2) is thought to be small, such as when excavating soft ground. Note that since the purpose of the jack 32 is to detect changes in pushing force (load), a small stroke is sufficient, and there is no need to grasp the amount of extension and retraction (stroke amount information). However, stroke amount information may be acquired to grasp the state of the jack 32 in more detail.

[0093] The above describes a preferred embodiment of the present invention with reference to the accompanying drawings. However, it goes without saying that the present invention is not limited to the above-described embodiment, and various modified or altered examples within the scope of the claims also fall within the technical scope of the present invention.

[0094] For example, although an earth pressure type (including mud pressure type) tunnel boring machine 1 has been described above, the tunnel boring machine according to the present invention may also be a mud water type.

[0095] Furthermore, for example, although the components of the tunnel boring machine 1 have been described above with reference to the drawings, the dimensions and positional relationships of the components in the drawings are merely examples, and the dimensions and positional relationships of the components of the tunnel boring machine 1 are not limited to the examples shown in the drawings. Furthermore, components may be added, deleted, or modified as appropriate for the tunnel boring machine 1 illustrated in the drawings. [Explanation of symbols]

[0096] 1. Tunnel boring machine 2. Face 10 Excavator body 11 Cutter Head 11e Cutter Bit (Cutting Tool) 11f Disc cutter (cutting tool) 12 Cutter central axis 13 Bulkhead 14 Rotating Ring 15 Connecting beam 16 Cutter rotation motor 17 Chamber 18 Screw conveyor 19 Shield Jack 20 Wear detection device 20A Wear Detection Device 20B Wear detection device 20C Wear detection device 21 Jack 21a main body 21b Rod 22 Pressing force detection sensor 23 Stroke sensor 24 Processing equipment 31 Soil pressure gauge 32 Jack 32a Housing 32b piston 32c rod 33 Oil pressure sensor C1 rotation axis F1 front P1 port P2 port S segment ST stroke volume TH threshold

Claims

1. A cylindrical excavator body, a cutter head rotatably mounted on the front end of the excavator body; a cutting tool provided on a front surface of the cutter head; A wear detection device for a tunnel boring machine comprising: a rod extendable from inside the cutter head to a position forward of the front surface of the cutter head; a processing device that performs a wear amount detection process in which the rod is extended forward of the front face of the cutter head, and the front and rear positions of the face are identified based on pressing force information that is information about the pressing force of the rod and stroke amount information that is information about the stroke amount of the rod, and the wear amount of the cutting tool is calculated based on the front and rear positions of the face; Equipped with Wear detection device.

2. the processing device retracts the rod into the inside of the cutter head when the cutter head is rotating and excavating a tunnel, and performs the wear amount detection process when the cutter head is not rotating. The wear detection device according to claim 1 .

3. In the wear amount detection process, the processing device continuously acquires the pressing force information and the stroke amount information as the rod extends, and identifies the front-rear position of the tip of the rod at the stroke amount at the time when the pressing force exceeds a threshold based on the pressing force information and the stroke amount information, and identifies the front-rear position as the front-rear position of the working face. The wear detection device according to claim 1 .

4. In the wear amount detection process, the processing device calculates a distance between a front-rear position of the tip of the cutting tool in an initial state and a front-rear position of the cutting face as the wear amount of the cutting tool. The wear detection device according to claim 1 .

5. a longitudinal position of the tip of the rod at the maximum stroke amount coincides with a longitudinal position of the tip of the cutting tool in an initial state, or is located behind the longitudinal position; The wear detection device according to claim 1 .

6. The cutting tool is a fixed cutting tool fixed to the cutter head. The wear detection device according to claim 1 .

7. The cutting tool is a rotary cutting tool rotatably attached to the cutter head. The wear detection device according to claim 1 .

8. The cutting tool is an exchangeable cutting tool exchangeably attached to the cutter head. The wear detection device according to claim 1 .

9. An earth pressure gauge is provided at the tip of the rod, the processing device acquires the pressing force information based on the detection result of the earth pressure meter. The wear detection device according to claim 1 .

10. A jack is provided at the tip of the rod, The processing device acquires the pressing force information based on information about the load of the jack. The wear detection device according to claim 1 .

11. A wear detection device according to any one of claims 1 to 10, Tunnel boring machine.

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