Tunnel boring machine

Abstract

To provide a tunnel boring machine capable of accurately obtaining a thrust acting on a swivel bearing.SOLUTION: This tunnel boring machine 100 comprises a swivel bearing 3 including a rotating wheel 4 attached to a cutter head 1 and rotating together with the cutter head 1, a rear thrust roller 6c, and a fixed wheel 5 that rotatably supports the rotating wheel 4 via the rear thrust roller 6c, a support member 7 that supports the fixed wheel 5 from a rear side, and a distance sensor 9 provided on the support member 7 and disposed to face a rear surface 51a of a thrust support portion 51 of the fixed wheel 5 that is pressed rearward by the rear thrust roller 6c, for obtaining deflection of the thrust support portion 51 that changes depending on the magnitude of a thrust acting on the swivel bearing 3.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to a tunnel boring machine having a swivel bearing that rotatably supports a cutter head. [Background technology]

[0002] BACKGROUND ART Conventionally, a tunnel boring machine equipped with a swivel bearing that rotatably supports a cutter head is known (see, for example, Patent Document 1).

[0003] Patent Document 1 discloses a shield tunneling machine equipped with a swivel bearing that rotatably supports a cutter head and a distance sensor located behind the rotating ring of the swivel bearing. The shield tunneling machine uses the distance sensor to measure the distance to the rear surface of the rotating ring of the swivel bearing, which changes depending on the magnitude of the thrust of the cutter head (swivel bearing), and obtains the deflection of the rotating ring. The shield tunneling machine is then configured to obtain the thrust of the cutter head (swivel bearing) based on the measurement value of the distance sensor. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 4869035 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the shield tunneling machine of Patent Document 1, tilting and undulation occur on the rear surface of the rotating wheel as the rotating wheel rotates due to factors such as the surface accuracy of the rear surface of the rotating wheel and the clearance between the support rollers that support the rotating wheel and the track surface (the contact surface of the rotating wheel that comes into contact with the support rollers during rotation), making the relationship between the distance to the rear surface of the rotating wheel, which is the measurement value of the distance sensor, and the thrust of the cutter head (swivel bearing) unreliable.For this reason, it is difficult to accurately obtain the magnitude of the thrust acting on the cutter head (swivel bearing) using this method of measuring the distance to the rear surface of the rotating wheel, and so there has been a need for a means of accurately obtaining the thrust acting on the cutter head (swivel bearing).

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide a tunnel boring machine that is capable of accurately obtaining the thrust acting on the swivel base bearing. [Means for solving the problem]

[0007] In order to achieve the above object, the tunnel boring machine of the present invention comprises a swivel base bearing including a rotating wheel attached to the cutter head and rotating together with the cutter head, a thrust roller, and a fixed wheel rotatably supporting the rotating wheel via the thrust roller, a support member supporting the fixed wheel from the rear, and a deflection acquisition sensor provided on the support member and positioned opposite the rear surface of the thrust support portion of the fixed wheel that is pressed rearward by the thrust roller, and for acquiring the deflection of the thrust support portion which changes depending on the magnitude of the thrust acting on the swivel base bearing.

[0008] As described above, the tunnel boring machine of this invention includes a support member that supports, from the rear, the fixed ring that rotatably supports the rotating ring via thrust rollers, and a deflection acquisition sensor that is attached to the support member and positioned facing the rear surface of the thrust support portion of the fixed ring that is pressed rearward by the thrust roller, for acquiring deflection of the thrust support portion, which changes depending on the magnitude of the thrust acting on the swivel head bearing. This allows the deflection acquisition sensor to measure the distance to the rear surface, which is the stationary surface of the fixed ring, rather than the rotating ring, thereby preventing tilt and waviness from occurring on the surface being measured. Furthermore, the deflection acquisition sensor can acquire deflection of the thrust support portion of the fixed ring, to which the thrust acting on the swivel head bearing is directly applied via the thrust rollers. In other words, the deflection acquisition sensor can measure deflection of the thrust support portion of the fixed ring of the swivel head bearing, which changes directly depending on the magnitude of the thrust acting on the swivel head bearing. As a result, the deflection acquisition sensor can accurately acquire deflection of the thrust support portion of the fixed ring. This makes it possible to obtain the thrust acting on the swivel base bearing with high accuracy.

[0009] The tunnel boring machine preferably further includes a control unit that acquires the deflection of the thrust support unit based on the measurement value of the deflection acquisition sensor and acquires the magnitude of the thrust acting on the swivel table bearing based on the acquired deflection of the thrust support unit. With this configuration, the magnitude of the thrust acting on the swivel table bearing can be acquired by the control unit, making it possible to determine whether an excessive load is acting on the swivel table bearing and drive units such as the cutter head.

[0010] In this case, the device preferably further includes an inner cylinder supported by a support member, including an inner partition wall 21a that defines a chamber on the inner periphery of the swivel base bearing, and an inner cylinder pressure sensor attached to the inner partition wall that measures the pressure the inner cylinder receives from the sediment and groundwater in the chamber. The control unit performs control to remove disturbances that the pressure measured by the inner cylinder pressure sensor imposes on the measurement value of the deflection acquisition sensor. This configuration can remove the influence on the measurement value of the deflection acquisition sensor that occurs when the inner cylinder receives pressure from the sediment, causing the support member to deform and the deflection acquisition sensor to move. Therefore, the deflection of the thrust support part of the fixed ring of the swivel base bearing, which changes depending on the magnitude of the thrust acting on the swivel base bearing, can be more accurately obtained by correcting the value obtained by the deflection acquisition sensor.

[0011] In the above tunnel boring machine, preferably, the fixed ring is fixed to the support member on the opposite side to the rotating ring in the radial direction of the swivel bearing, and the deflection acquisition sensor is arranged facing the rotating ring near the swivel bearing. With this configuration, the fixed ring and the support member can be fixed to a position far from the thrust roller and the thrust support portion of the fixed ring to form a fixed end, and the thrust support portion can be formed as a free end, so that the force with which the thrust roller presses the thrust support portion of the fixed ring can cause a relatively large deformation of the thrust support portion.

[0012] In this case, preferably, on the side where the radial deflection acquisition sensor for the swivel base bearing is located, a gap of a predetermined width is provided between the rear surface of the thrust support part of the fixed ring and the front surface of the support member when no load is applied to the cutter head, and the deflection acquisition sensor includes a distance sensor that measures the size of the gap as a measurement value corresponding to the deflection of the thrust support part. With this configuration, the deflection of the thrust support part of the fixed ring can be easily acquired by measuring the amount of change in the gap with the distance sensor.

[0013] In the configuration in which the deflection acquisition sensor includes a distance sensor, the distance sensor is preferably an eddy current displacement sensor disposed opposite the rear surface across a gap. With this configuration, the eddy current displacement sensor can measure the deflection of the thrust support portion of the swivel table bearing without the measurement value being affected by the pressure or grease around the area where the eddy current displacement sensor is disposed.

[0014] In the above-described configuration in which the deflection acquisition sensor is disposed opposite the fixed ring near the rotating ring in the radial direction of the swivel base bearing, preferably, on the side of the swivel base bearing where the deflection acquisition sensor is disposed, a gap of a predetermined width is provided between the rear surface of the thrust support part of the fixed ring and the front surface of the support member in the front-to-rear direction when no load is applied to the cutter head, and the deflection acquisition sensor includes a load cell that measures a compressive force that changes with the size of the gap as a measurement value corresponding to the deflection of the thrust support part. With this configuration, the load cell can obtain a measurement value that changes directly with the deflection of the thrust support part of the fixed ring, making it easy to obtain the deflection of the thrust support part of the fixed ring.

[0015] In the above-described configuration in which the deflection sensor is disposed facing the fixed ring near the rotating ring in the radial direction of the swivel base bearing, preferably, on the side of the swivel base bearing where the deflection sensor is disposed, the rear surface of the thrust support portion of the fixed ring abuts against the front surface of the support member, and the deflection sensor includes a radial strain sensor disposed in abutment against the rear surface of the fixed ring and measuring radial strain in the radial direction of the support member as a measurement value corresponding to the deflection of the thrust support portion. This configuration allows the radial strain sensor to be disposed in abutment against the rear surface of the fixed ring. Therefore, in a tunnel boring machine or the like that is relatively large and requires high rigidity, the deflection of the thrust support portion of the fixed ring can be obtained without reducing rigidity by providing a gap between the fixed ring and the support member. [Effects of the Invention]

[0016] According to the present invention, as described above, the thrust acting on the swivel base bearing can be obtained with high accuracy. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional side view of a tunnel boring machine according to a first embodiment. FIG. [Figure 2] 2 is an enlarged view of part A in FIG. 1, showing a swivel base bearing, a support member, and a distance sensor. FIG. [Figure 3] FIG. 2 is a rear view of the support members, distance sensors, and drive motors of the tunnel boring machine according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram for explaining deformation of the thrust support portion of the fixed ring of the swivel table bearing of the tunnel boring machine according to the first embodiment. [Figure 5] FIG. 4 is a schematic diagram for explaining deformation of a support member of the tunnel boring machine according to the first embodiment. [Figure 6] 10 is a graph showing the relationship between the cutter head thrust and the gap reduction amount when the inner cylinder load is changed. [Figure 7] 10 is a graph showing the relationship between an inner cylinder load and an increase in a gap. [Figure 8] 10 is a graph for explaining the influence of the presence or absence of an inner cylinder load on the relationship between the cutter head thrust and the gap reduction amount. [Figure 9] 10 is a graph showing the relationship between the amount of gap reduction due to the cutter head thrust and the cutter head thrust. [Figure 10] 10 is a diagram showing a distribution load of the cutter head and the inner peripheral partition wall portion in a normal state. FIG. [Figure 11] 11 is a diagram showing an example of a display on the control panel in the state shown in FIG. 10. FIG. [Figure 12] FIG. 10 is a diagram showing the cutter head and the tunnel boring machine when they come into contact with an obstacle. [Figure 13] 13 is a diagram showing an example of a display on the control panel in the state shown in FIG. 12. FIG. [Figure 14]FIG. 10 is a diagram showing a swivel base bearing, a support member, and a load cell of a tunnel boring machine according to a second embodiment, and corresponds to FIG. 2. [Figure 15] FIG. 10 is a diagram showing a swivel base bearing, a support member, and a radial strain sensor of a tunnel boring machine according to a third embodiment, and corresponds to FIG. 2. [Figure 16] FIG. 10 is a diagram showing a swivel base bearing, a support member, and a distance sensor of a tunnel boring machine according to a fourth embodiment, and corresponds to FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0019] [First embodiment] (Tunnel boring machine configuration) A tunnel boring machine 100 according to a first embodiment will be described with reference to FIGS.

[0020] In each drawing, the direction parallel to the central axis α of the tunnel boring machine 100, which extends along the excavation direction (front-rear direction), is indicated as the X direction. Of the X directions, the excavation direction (front) is indicated as the X1 direction, and the other direction (rear) is indicated as the X2 direction. The central axis α is also the central axis of the cutter head 1, swivel bearing 3, body 20, etc.

[0021] In each figure, the left-right direction is indicated by the Y direction. Within the Y direction, the right is indicated by the Y1 direction, and the left is indicated by the Y2 direction. In each figure, the up-down direction is indicated by the Z direction. Within the Z direction, the up is indicated by the Z1 direction, and the down is indicated by the Z2 direction. In each figure, the radial direction of the tunnel boring machine 100 (swivel table bearing 3) is indicated by the R direction. Within the radial direction, the direction facing radially outward is indicated by R1, and the direction facing radially inward is indicated by R2. In each figure, the rotation direction of the swivel table bearing 3 is indicated by the r direction.

[0022] As shown in Figure 1, the tunnel boring machine 100 comprises a cutter head 1, a body 20, a bulkhead 21, a plurality of propulsion jacks 23 and a plurality of articulating jacks 24, a swivel base bearing 3, a support member 7 that supports the swivel base bearing 3, an inner cylinder 8, an inner cylinder pressure sensor 8a, a distance sensor 9 provided on the support member 7, and a control unit 101. A plurality of distance sensors 9 are provided so as to be aligned in the rotation direction (direction r). The distance sensor 9 is an example of a "deflection acquisition sensor" in the claims.

[0023] The tunnel boring machine 100 (control unit 101) is configured to perform control to acquire (estimate) the magnitude of the thrust acting on the swivel table bearing 3 based on the measurement value of the distance sensor 9. In other words, the "thrust acting on the swivel table bearing 3" is the force with which the cutter head 1 is pushed backward from the ground by the thrust of excavation. Details of the control performed by the control unit 101 will be described later.

[0024] In the first embodiment, an example is shown in which the tunnel boring machine 100 is an earth pressure type tunnel boring machine. In the earth pressure type tunnel boring machine 100, the earth and sand excavated by the cutter head 1 and a mud-making material injected into the earth and sand are mixed in the chamber C, and the excavated earth and sand is converted into mud that is impermeable and has plastic flow properties. The tunnel boring machine 100 is propelled by the propulsion jacks 23, which fills the chamber C with the excavated earth and sand (mud), pressurizing it and countering the pressure (earth pressure and groundwater pressure) on the ground side. The tunnel boring machine 100 then advances in the excavation direction while balancing the pressure by balancing the amount of excavation and the amount of soil discharged.

[0025] (Cutter head configuration) The cutter head 1 is configured to rotate around a central axis α to excavate the ground. The force acting on the cutter head 1 from the ground typically increases gradually downward (see FIG. 10). Similarly, the inner circumferential partition 21a, which is the front surface of the inner cylinder 8, is also subjected to gradually increasing forces from soil and groundwater as it moves downward (see FIG. 10). Note that the forces acting on the inner circumferential partition 21a from soil and groundwater are generally smaller than the forces acting on the cutter head 1 from soil. When an obstacle such as a boulder in the ground comes into contact with the cutter head 1, the force acting on the cutter head 1, i.e., the thrust acting on the swivel bearing 3, is particularly large on the side where the obstacle is located, as viewed from the front to back. As a result, the thrust acting on the swivel bearing 3 becomes uneven (see FIGS. 12 and 13). The tunnel boring machine 100 (control unit 101) is capable of obtaining the bias of the thrust force acting on the swivel table bearing 3, that is, the biased load, based on the measurement values ​​of the plurality of distance sensors 9. This point will also be described later.

[0026] The cutter head 1 is supported from the rear by multiple support legs 10. The multiple support legs 10 are arranged circumferentially at predetermined angular intervals in the rotational direction of the swivel bearing 3. The multiple support legs 10 are arranged on the outer periphery (R1 direction side) of the cutter head 1 in the radial direction. In other words, the cutter head 1 is a peripheral support type cutter head that is supported on the outer periphery side. A circular cutter column 11 is fixed to the multiple support legs 10 from the rear. Furthermore, a rotating ring 4, which is the inner ring of the swivel bearing 3, is fixed to the cutter column 11 from the rear.

[0027] (Fuselage and bulkhead configuration) The fuselage 20 includes a front barrel 20a and a rear barrel 20b located rearward of the front barrel 20a. A partition 21 is provided inside the front barrel 20a, dividing the interior space of the front barrel 20a into a chamber C on the front side and a work space on the rear side. The partition 21 includes an inner partition 21a that divides the chamber C on the inner side of the swivel bearing 3, and an outer partition 21b that divides the chamber C on the outer side of the swivel bearing 3. The front end of a screw conveyor 22 is fixed to the lower side of the partition 21. The screw conveyor 22 is connected to the chamber C and is configured to discharge soil and sand from the chamber C toward the work space.

[0028] (Configuration of multiple propulsion jacks and multiple folding jacks) The multiple propulsion jacks 23 are arranged circumferentially at predetermined angular intervals in the rotational direction of the swivel bearing 3. The multiple propulsion jacks 23 are fixed to the rear body 20b and are configured to extend and retract to push the excavator body forward.

[0029] The multiple articulating jacks 24 are arranged circumferentially at predetermined angular intervals in the rotational direction of the cutter head 1. The multiple articulating jacks 24 are fixed to the body 20 so as to straddle the front body 20a and the rear body 20b, and are configured to extend and retract to change the orientation of the front body 20a relative to the rear body 20b, thereby correcting or changing the excavation direction of the tunnel boring machine 100.

[0030] Here, during excavation, four main forces act on the articulating jack 24: a force acting on the cutter head 1 from the ground; a force acting on the inner peripheral partition wall 21a from soil and groundwater; a force acting on the outer peripheral partition wall 21b from soil and groundwater; and a frictional force between the ground and the outer peripheral surface of the body 20. The frictional force between the ground and the outer peripheral surface of the body 20 can be minimized by creating a space between the outer peripheral surface of the body 20 and the ground by over-excavating, or by injecting a lubricant between the outer peripheral surface of the body 20 and the ground.

[0031] (Configuration of swivel bearing) As shown in Figures 1 and 3, the swivel base bearing 3 is a swivel base bearing with a rotating inner ring and a fixed outer ring. In detail, the swivel base bearing 3 includes a rotating ring 4, which is the inner ring, a fixed ring 5, which is the outer ring, a radial roller 6a, a front thrust roller 6b, and a rear thrust roller 6c, which is located behind the front thrust roller 6b. The rear thrust roller 6c is an example of the "thrust roller" defined in the claims.

[0032] As shown in FIG. 3, the rotating wheel 4 is attached to the cutter head 1 and is configured to rotate together with the cutter head 1. The rotating wheel 4 has an annular shape. The inner peripheral surface of the rotating wheel 4 is provided with internal teeth 40 that mesh with the output gear M1 of the drive motor M. The rotating wheel 4 includes a rotating wheel flange portion 41 that protrudes radially outward (toward the R1 direction) from a main body portion fixed to the cutter column 11. In cross section as viewed from the side, the rotating wheel flange portion 41 is formed in a rectangular convex shape having a front surface, an outer peripheral surface, and a rear surface. A front thrust roller 6b is arranged along this front surface, a radial roller 6a is arranged along the outer peripheral surface, and a rear thrust roller 6c is arranged along the rear surface.

[0033] The fixed ring 5 rotatably supports the rotating ring 4 via a radial roller 6a, a front thrust roller 6b, and a rear thrust roller 6c. The fixed ring 5 has an annular shape. An outer ring recessed portion 50 that is recessed from the rotating ring 4 side is provided on the rotating ring 4 side of the fixed ring 5. The rotating ring flange portion 41 is disposed inside the outer ring recessed portion 50, with the radial roller 6a, front thrust roller 6b, and rear thrust roller 6c sandwiched between the outer ring recessed portion 50 and the rotating ring flange portion 41.

[0034] The fixed wheel 5 includes a thrust support portion 51 that is pressed rearward via the rear thrust roller 6c of the fixed wheel 5. This pressing force F1 (see FIG. 4) is generated when the force acting on the cutter head 1 from the soil is transmitted to the rotating wheel 4. The thrust support portion 51 of the fixed wheel 5 is a portion located rearward of the rear thrust roller 6c and the rotating wheel flange portion 41 of the rotating wheel 4. The thrust support portion 51 of the fixed wheel 5 is also a portion sandwiched between the rear thrust roller 6c and the support member 7.

[0035] In the radial direction (R direction) of the swivel base bearing 3, the fixed ring 5 is fixed to the support member 7 on the side opposite to the rotating ring 4 by a fixing member 52, and a distance sensor 9 is arranged facing the rotating ring 4 near the rotating ring 4. That is, the fixed ring 5 is fixed to the support member on the outer circumferential side (R1 direction side) and faces the distance sensor 9 on the inner circumferential side (R2 direction side). As an example, the fixing member 52 is a bolt that screws into the fixed ring 5 from the rear side of the support member 7 through a screw hole that penetrates the support member 7 from front to rear. This bolt is arranged outer circumferentially closer to the radial roller 6a and extends forward of the front thrust roller 6b.

[0036] On the radial side of the swivel base bearing 3 where the distance sensor 9 is arranged (the R2 side), a gap S of a predetermined width (initial width) is provided between the rear surface 51a of the thrust support portion 51 of the fixed wheel 5 and the front surface 71 of the support member 7 when no load is applied to the cutter head 1 (when the thrust support portion 51 of the fixed wheel 5 and the support member 7 are in an undeformed state). As an example, the predetermined width (initial width) is the gap S of size W0 (see FIGS. 4 and 5) between 1 mm and 2 mm. Therefore, in a cross section viewed from the side, the thrust support portion 51 of the fixed wheel 5 is formed like a cantilever beam with the outer circumferential side, which is the side of the fixed wheel 5 fixed to the support member 7, as the fixed end and the inner circumferential side as the free end.

[0037] As an example, the gap S is provided at least in a range in the radial direction corresponding to the rear surface 51a of the thrust support portion 51 of the fixed wheel 5. As a more detailed example, the gap S is provided in a range in the radial direction that is slightly wider than the range corresponding to the rear surface 51a. The outer peripheral end of the gap S is located at a position in the radial direction corresponding to the radial roller 6a.

[0038] (Configuration of support member) The support member 7 supports the fixed ring 5 of the swivel base bearing 3 from the rear. The support member 7 is a ring-shaped (flange-shaped) steel member that extends radially and has a circular hole in the center, and the end on the outer periphery (R1 direction side) is directly fixed to the front body 20a. Note that the support member may also be indirectly fixed to the front body 20a via another member.

[0039] The support member 7 has an abutment surface 70 on its outer periphery that abuts against the fixed wheel 5. The support member 7 also has a front surface 71 on the inner periphery of the abutment surface 70, which forms a gap S with the rear surface 51a of the thrust support portion 51. The front surface 71 is located one step rearward (in the X2 direction) from the abutment surface 70. Both the front surface 71 and the abutment surface 70 are flat. When no load is applied to the cutter head 1 (when the thrust support portion 51 of the fixed wheel 5 and the support member 7 are in an undeformed state), the front surface 71 and the abutment surface 70 extend in a radial direction perpendicular to the front-to-rear direction and are parallel to each other. In this case, the size W of the gap S between the front surface 71 of the support member 7 and the rear surface 51a of the thrust support portion 51 is a predetermined width (initial width) W0 (see FIGS. 4 and 5).

[0040] As shown in FIG. 1, the drive motor M is installed on the support member 7 on the inner peripheral side (R2 direction side) of the swivel base bearing 3. When the drive motor M is installed on the support member 7, the output gear M1 is arranged in front of the support member 7, and the main body of the drive motor M is arranged behind the support member 7. The support member 7 has a sensor installation hole 72 that penetrates the support member 7 from front to back. A distance sensor 9 is installed inside the sensor installation hole 72. The front end of the sensor installation hole 72 is connected to the front surface 71 of the support member 7.

[0041] (Configuration of inner cylinder) The inner cylinder 8 shown in FIG. 1 is an annular cylindrical portion located more inward than the swivel bearing 3 and the distance sensor 9. The inner cylinder 8 is supported by the rear support member 7. The inner cylinder 8 is fixed to the inner peripheral portion of the support member 7. The inner cylinder 8 has a non-rotating structure that does not rotate when the cutter head 1 rotates. The inner cylinder 8 includes an inner peripheral partition wall portion 21a that defines a chamber C on the inner peripheral side of the swivel bearing 3. The front end of the screw conveyor 22 is fixed to the inner cylinder 8.

[0042] The inner cylinder 8 is configured so that when pressure is applied from soil and groundwater in the chamber C during excavation, the inner peripheral partition portion 21a is pushed in the front-to-rear direction, causing it to displace rearward relative to the swivel bearing 3.

[0043] (Configuration of inner cylinder pressure sensor) The inner cylinder pressure sensor 8a is provided on the inner circumferential partition wall portion 21a and is configured to measure the pressure that the inner cylinder 8 receives from the sediment in the chamber C. The measurement value (measurement value data D1) of the inner cylinder pressure sensor 8a is acquired by the control unit 101.

[0044] (Distance sensor configuration) As shown in FIG. 3, the distance sensor 9 is provided on the support member 7. The distance sensor 9 is disposed in a sensor installation hole 72 of the support member 7. The distance sensor 9 is disposed facing the rear surface 51a of the thrust support portion 51 of the fixed wheel 5, which is pressed rearward by the rear thrust roller 6c. The distance sensor 9 is a sensor for acquiring the deflection of the thrust support portion 51, which changes depending on the magnitude of the thrust acting on the swivel base bearing 3. Multiple distance sensors 9 are provided on the support member 7 (see FIG. 2). As an example, eight distance sensors 9 are provided. The multiple distance sensors 9 are disposed circumferentially at predetermined angular intervals in the rotation direction (direction r) of the swivel base bearing 3.

[0045] Distance sensor 9 is a sensor that measures the size W of gap S as a measurement value corresponding to the deflection of thrust support part 51. Distance sensor 9 is an eddy current displacement sensor that is placed opposite rear surface 51a of thrust support part 51 across gap S. Eddy current displacement sensors are sensors that can measure distance without contact. Eddy current displacement sensors supply a high-frequency signal to a sensor coil to generate high-frequency magnetic flux, detect the magnitude of eddy currents generated in the target, and output a signal proportional to the distance.

[0046] The eddy current displacement sensor generates an eddy current on the rear surface 51a of the thrust support part 51 due to electromagnetic induction with the rear surface 51a of the thrust support part 51 in the generated high-frequency magnetic field, causing a change in the impedance of the sensor coil. This change is converted into a signal proportional to the distance, and measures the distance (size W of gap S) between the distance sensor 9 and the rear surface 51a of the thrust support part 51. In the front-to-rear direction, the position of the detection surface of the distance sensor 9 coincides with the position of the front surface 71 of the support member 7. The measurement value of the distance sensor 9 (measurement value data D2 (see Figure 1)) is acquired by the control unit 101.

[0047] (Deformation of the thrust support part of the fixed ring due to the thrust of the cutter head, and deformation of the support member due to pressure on the inner peripheral partition wall of the inner cylinder) Before explaining the control unit 101, the deformation of the thrust support portion 51 of the fixed wheel 5 due to the thrust of the cutter head 1 and the deformation of the support member 7 due to the pressure of the inner peripheral partition portion 21a of the inner cylinder 8 will be explained with reference to Figures 4 and 5, respectively.

[0048] First, the state shown in Figure 4(A) is a state where no load is acting on the cutter head 1 (the thrust support portion 51 of the fixed wheel 5 and the support member 7 are in a non-deformed state), and the size of the gap S measured by the distance sensor 9 is a preset value W0 (initial width). In the explanation of Figure 4, the effect of the force acting from the soil and sand on the inner cylinder 8 is ignored.

[0049] 4(B), when a load is applied to the cutter head 1, a force F1 is applied from the rotating wheel 4 via the rear thrust roller 6c to the thrust support portion 51 of the fixed wheel 5 in response to the thrust (thrust acting on the swivel bearing 3). As a result, the thrust support portion 51, which has the inner peripheral end portion as the free end, bends rearward. This reduces the gap S, and the size of the gap S measured by the distance sensor 9 becomes W1, which is smaller than W0.

[0050] Next, the state shown in Figure 5(A) is a state where no load is acting on the cutter head 1 (the thrust support portion 51 of the fixed wheel 5 and the support member 7 are in a non-deformed state), and the size of the gap S measured by the distance sensor 9 is a preset value W0 (initial width). In the explanation of Figure 5, the force acting on the cutter head 1 from the soil and sand (thrust of the cutter head 1) will be ignored.

[0051] 5(B), when pressure acts on the inner peripheral partition wall portion 21a of the inner cylinder 8, a force F2 acts from the inner cylinder 8 to press the support member 7 rearward. As a result, the support member 7 bends rearward and moves rearward together with the distance sensor 9. This causes the gap S to expand, and the size of the gap S measured by the distance sensor 9 becomes W2, which is larger than W0.

[0052] (Configuration of control unit) 1 includes a CPU, a ROM, a RAM, etc. A control panel 101a having a display unit that displays the control results of the control unit 101 is connected to the control unit 101. The control unit 101 and the control panel 101a are disposed at predetermined locations within the body 20.

[0053] The control unit 101 acquires the deflection of the thrust support part 51 of the fixed wheel 5 based on the measurement value of the distance sensor 9, and performs control to acquire (estimate) the magnitude of the thrust acting on the swivel base bearing 3 based on the acquired deflection of the thrust support part 51.

[0054] The control unit 101 also performs control to remove disturbances that the pressure measured by the inner cylinder pressure sensor 8a causes to the measurement value of the distance sensor 9. This improves the accuracy of the magnitude of the thrust force acting on the swivel base bearing 3 that is obtained.

[0055] The control for acquiring (estimating) the magnitude of the thrust force acting on the swivel table bearing 3 will be described in detail with reference to FIGS.

[0056] FIG. 6 shows the relationship between the thrust of the cutter head 1 (swivel bearing 3) and the amount of clearance reduction when the inner cylinder load is changed. In FIG. 6, the direction in which the clearance S narrows is indicated by a positive value. The inner cylinder load is the pressure with which the soil and sand presses against the inner circumferential partition wall portion 21a, and can be measured by the inner cylinder pressure sensor 8a (see FIG. 1). As the inner cylinder load increases, the straight line in the graph shown in FIG. 6 shifts downward. In other words, even with the same thrust of the cutter head 1, the amount of reduction in the clearance S decreases as the inner cylinder load increases.

[0057] Figure 7 shows the relationship between the load on the inner cylinder and the increase in the gap. In Figure 7, the direction in which the gap S widens is indicated by a positive sign. This is just one example, but the relationship between the load on the inner cylinder and the increase in the gap can be obtained by comprehensively analyzing the results of a specified structural analysis, the results of measurements when an inner cylinder load is actually applied by soil and sand in chamber C, or both.

[0058] Figure 8 shows a method for correcting the measured gap reduction to the gap reduction due only to the influence of the thrust of the cutter head 1. When there is no inner cylinder load, the measured gap reduction and the gap reduction due to the thrust of the cutter head 1 are equal. When there is an inner cylinder load, the measured gap reduction plus the gap increase corresponding to the measured inner cylinder load is the gap reduction due to the thrust of the cutter head 1. In other words, if the measured gap reduction is "1" and the gap increase due to the inner cylinder load is "2", the gap reduction "3" due to the thrust of the cutter head 1 is "3" = "1" + "2" (see Figure 9).

[0059] FIG. 9 shows the relationship between the amount of clearance reduction due to the thrust of the cutter head 1 and the thrust of the cutter head 1. This relationship is determined, for example, by comprehensively analyzing the results of structural analysis and measurements of the thrust value and clearance S of the articulating jack 24 during excavation and when stopped. As described above, the thrust of the articulating jack 24 is primarily affected by four forces during excavation: forces acting on the cutter head 1 from the ground; forces acting on the inner circumferential partition wall 21a from soil, sand, groundwater, etc. (inner cylinder load); forces acting on the outer circumferential partition wall 21b from soil, sand, groundwater, etc. (main body partition pressure load); and frictional forces between the outer circumferential surface of the body 20 and the ground. The inner cylinder load can be measured by the inner cylinder pressure sensor 8a. The main body partition pressure load can also be measured by a pressure sensor (not shown) provided on the outer circumferential partition wall 21b.

[0060] Although it is difficult to directly measure the friction force between the outer surface of the body 20 and the ground, it can be minimized by creating a space between the outer surface of the body 20 and the ground by over-excavating, or by injecting a lubricant between the outer surface of the body 20 and the ground. Therefore, the control unit 101 can estimate the thrust of the cutter head 1 (thrust acting on the swivel bearing 3) based on the thrust of the articulating jack 24, etc., in addition to the measurement value of the distance sensor 9.

[0061] In addition, the control unit 101 can obtain not only the thrust of the cutter head 1 (thrust acting on the swivel bearing 3), but also the bias in the thrust of the cutter head 1 (biased load) from the measurement value data D2 (see Figure 1) of multiple distance sensors 9 arranged on the circumference.

[0062] More specifically, referring to Figures 10 and 11, under normal conditions, the pressure load acting on each of the cutter head 1 and the inner peripheral partition wall portion 21a has a trapezoidal distribution as shown in Figure 10. The display unit of the operation panel 101a displays the average load value acting on the cutter head 1, the allowable average load, the unbalanced load state, the unbalanced load center of gravity, and the allowable unbalanced load in this state. For example, the display unit of the operation panel 101a displays that the load average value is normal if it is within the circle of the allowable average load. This enables the tunnel boring machine 100 to reduce the risk of damage to the cutter head 1 and drive parts such as the swivel table bearing 3. In this case, the unbalanced load center of gravity will shift downward along the left-right center line.

[0063] 12 and 13, if an obstacle such as a boulder is present in the upper right corner near the rear, the average load value will be within the circle of the allowable average load, but the center of gravity of the unbalanced load will exceed the circle of the allowable unbalanced load. In this case, as an example, the display on the operation panel 101a will display an abnormal state. This makes it possible to know that the tunnel boring machine 100 is in a state where there is a high risk of damage to the drive parts, such as the cutter head 1 and the swivel table bearing 3.

[0064] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0065] As described above, the first embodiment includes the support member 7 that supports, from the rear, the fixed wheel 5 that rotatably supports the rotating wheel 4 via the rear thrust roller 6c, and a deflection acquisition sensor (distance sensor 9) that is provided on the support member 7 and disposed opposite the rear surface 51a of the thrust support portion 51 of the fixed wheel 5 that is pressed rearward by the rear thrust roller 6c, for acquiring the deflection of the thrust support portion 51 that changes depending on the magnitude of the thrust acting on the swivel base bearing 3. This allows the deflection acquisition sensor to measure the distance to the rear surface 51a, which is the stationary surface of the fixed wheel 5, rather than the rotating wheel 4, thereby preventing tilt and waviness from occurring on the surface to be measured. The deflection acquisition sensor also allows the deflection of the thrust support portion 51 of the fixed wheel 5 to be acquired, to which the thrust acting on the swivel base bearing 3 is directly applied via the rear thrust roller 6c. That is, the deflection acquisition sensor can measure the deflection of the thrust support portion 51 of the fixed ring 5 of the swivel base bearing 3, which changes directly depending on the magnitude of the thrust acting on the swivel base bearing 3. As a result, the deflection acquisition sensor can accurately acquire the deflection of the thrust support portion 51 of the fixed ring 5. This makes it possible to accurately acquire the thrust acting on the swivel base bearing 3.

[0066] As described above, the first embodiment further includes a control unit 101 that acquires the deflection of the thrust support unit 51 based on the measurement value of the deflection acquisition sensor (distance sensor 9) and performs control to acquire the magnitude of the thrust acting on the swivel table bearing 3 based on the acquired deflection of the thrust support unit 51. This allows the control unit 101 to acquire the magnitude of the thrust acting on the swivel table bearing 3, making it possible to determine whether an excessive load is acting on the swivel table bearing 3 and drive units such as the cutter head 1.

[0067] As described above, the first embodiment further includes the inner cylinder 8, which includes the inner partition wall 21a that defines the chamber C on the inner periphery of the swivel base bearing 3 and is supported by the support member 7, and the inner cylinder pressure sensor 8a, which is attached to the inner partition wall 21a and measures the pressure that the inner cylinder 8 receives from the sediment and groundwater in the chamber C. The control unit 101 performs control to remove disturbances that the pressure measured by the inner cylinder pressure sensor 8a applies to the measurement value of the deflection acquisition sensor (distance sensor 9). This can remove the influence on the measurement value of the deflection acquisition sensor that occurs when the inner cylinder 8 receives pressure from the sediment, causing the support member 7 to deform and the deflection acquisition sensor to move. Therefore, the deflection of the thrust support part 51 of the fixed ring 5 of the swivel base bearing 3, which changes depending on the magnitude of the thrust acting on the swivel base bearing 3, can be more accurately obtained by correcting the value obtained by the deflection acquisition sensor.

[0068] In the first embodiment, as described above, the fixed ring 5 is fixed to the support member 7 on the opposite side to the rotating ring 4 in the radial direction of the swivel bearing 3, and a deflection acquisition sensor (distance sensor 9) is arranged facing the rotating ring 4 near the rotating ring 4. This allows the fixed ring 5 and the support member 7 to be fixed at a position far from the rear thrust roller 6c and the thrust support portion 51 of the fixed ring 5 to form a fixed end, and allows the thrust support portion 51 to be on the free end side. Therefore, the force with which the rear thrust roller 6c presses the thrust support portion 51 of the fixed ring 5 can cause a relatively large deformation of the thrust support portion 51.

[0069] In the first embodiment, as described above, on the side where the radial deflection acquisition sensor of the swivel base bearing 3 is arranged, a gap S of a predetermined width is provided between the rear surface 51a of the thrust support portion 51 of the fixed wheel 5 and the front surface 71 of the support member 7 when no load is applied to the cutter head 1, and the deflection acquisition sensor includes a distance sensor 9 that measures the size of the gap S as a measurement value corresponding to the deflection of the thrust support portion 51. In this way, the deflection of the thrust support portion 51 of the fixed wheel 5 can be easily acquired by measuring the amount of change in the gap S using the distance sensor 9.

[0070] In the first embodiment, as described above, the distance sensor 9 is an eddy current displacement sensor arranged facing the rear surface 51a across the gap S. This allows the eddy current displacement sensor to measure the deflection of the thrust support part 51 of the swivel base bearing 3 without the measurement value being affected by the pressure or grease around where the eddy current displacement sensor is arranged.

[0071] [Second embodiment] A second embodiment will be described with reference to Fig. 14. Unlike the first embodiment described above which is provided with a distance sensor 9 for obtaining the deflection of the thrust support portion 51 of the fixed wheel 5, this second embodiment will describe an example in which a load cell 209 for obtaining the deflection of the thrust support portion 51 of the fixed wheel 5 is provided. Note that in the drawing, the same components as those in the first embodiment are denoted by the same reference numerals.

[0072] As shown in Figure 14, a tunnel boring machine 200 according to the second embodiment is equipped with a load cell 209 provided on the support member 7. The load cell 209 is an example of a "deflection acquisition sensor" in the claims.

[0073] The load cell 209 is a sensor for obtaining the deflection of the thrust support part 51, which changes depending on the magnitude of the thrust acting on the swivel base bearing 3. The load cell 209 includes a mounting bolt 209a and a load cell main body 209b. The load cell main body 209b has an annular shape, and the mounting bolt 209a is inserted through it.

[0074] The mounting bolt 209a is passed through the sensor installation hole 72 of the support member 7 and is threaded into a screw hole provided in the rear surface 51a of the thrust support portion 51 of the fixed wheel 5. The load cell main body 209b is always held in a compressed state in the front-to-rear direction. That is, due to the initial tension of the mounting bolt 209a, the load cell main body 209b is disposed in a compressed state between the rear surface 73 of the support member 7 and the head of the mounting bolt 209a when no load is acting on the cutter head 1 (the thrust support portion 51 of the fixed wheel 5 and the support member 7 are in an undeformed state).

[0075] On the radial side of the swivel bearing 3 where the load cell 209 is arranged (the R2 side), a gap S of a predetermined width is provided between the rear surface 51a of the fixed wheel 5 and the front surface 71 of the support member 7 when no load is applied to the cutter head 1. The load cell 209 is configured to measure the compressive force that changes with the size of the gap S as a measurement value corresponding to the deflection of the thrust support part 51.

[0076] The control unit 101 acquires the deflection of the thrust support unit 51 based on the measurement value of the load cell 209, and also performs control to acquire the magnitude of the thrust acting on the swivel table bearing 3 based on the acquired deflection of the thrust support unit 51. The load cell 209 directly acquires the compressive force of the load cell main body 209b as a measurement value. From the measurement value of the compressive force acquired by this load cell 209 (reduction in the initial tension of the bolt), the size W of the gap S between the rear surface 51a of the thrust support unit 51 and the front surface 71 of the support member 7 as described in the first embodiment is acquired. Thereafter, the control unit 101 performs control to acquire the magnitude of the thrust acting on the swivel table bearing 3 in the same manner as in the first embodiment.

[0077] The other configurations of the second embodiment are the same as those of the first embodiment.

[0078] (Effects of the second embodiment) In the second embodiment, the following effects can be obtained.

[0079] As described above, the second embodiment includes the support member 7 that supports, from the rear, the fixed wheel 5 that rotatably supports the rotating wheel 4 via the rear thrust roller 6c, and a deflection acquisition sensor (load cell 209) that is provided on the support member 7 and arranged opposite the rear surface 51a of the thrust support part 51 of the fixed wheel 5 that is pressed rearward by the rear thrust roller 6c, and that acquires the deflection of the thrust support part 51 that changes depending on the magnitude of the thrust acting on the swivel base bearing 3. As a result, the thrust acting on the swivel base bearing 3 can be acquired with high accuracy, just like the first embodiment.

[0080] In the second embodiment, as described above, on the side where the radial deflection acquisition sensor of the swivel base bearing 3 is arranged, a gap S of a predetermined width is provided between the rear surface 51a of the thrust support portion 51 of the fixed wheel 5 and the front surface 71 of the support member 7 when no load is applied to the cutter head 1, and the deflection acquisition sensor includes a load cell 209 that measures a compressive force that changes with the size of the gap S as a measurement value corresponding to the deflection of the thrust support portion 51. In this way, the load cell 209 can acquire a measurement value that changes directly with the deflection of the thrust support portion 51 of the fixed wheel 5, and therefore the deflection of the thrust support portion 51 of the fixed wheel 5 can be easily acquired.

[0081] Other effects of the second embodiment are the same as those of the first embodiment.

[0082] [Third embodiment] A third embodiment will be described with reference to Fig. 15. Unlike the first embodiment described above which is provided with a distance sensor 9 for obtaining the deflection of the thrust support portion 51 of the fixed wheel 5, this third embodiment will describe an example in which a radial strain sensor 309 for obtaining the deflection of the thrust support portion 51 of the fixed wheel 5 is provided. Note that in the drawing, the same components as those in the first embodiment are denoted by the same reference numerals.

[0083] As shown in Figure 15, a tunnel boring machine 300 according to the third embodiment comprises a support member 307 and a radial strain sensor 309 provided on the support member 307. The radial strain sensor 309 is an example of a "deflection acquisition sensor" in the claims.

[0084] Unlike the first embodiment, the rear surface 51a of the fixed wheel 5 and the front surface 371 of the support member 307 abut against each other on the side (R2 direction side) where the radial strain sensor 309 is arranged in the radial direction of the swivel base bearing 3. The front surface 371 of the support member 307 abuts against the rear surface 51a of the thrust support part 51 of the fixed wheel 5. In other words, there is no gap between the front surface 371 and the rear surface 51a. The radial strain sensor 309 is arranged in the sensor installation hole 72. The radial strain sensor 309 is provided with a seal member 309a for sealing the radial strain sensor 309. The seal member 309a is arranged along the interface between the front surface 371 and the rear surface 51a.

[0085] The radial strain sensor 309 is a sensor for acquiring the deflection of the thrust support part 51, which changes depending on the magnitude of the thrust acting on the swivel base bearing 3. The radial strain sensor 309 is arranged in contact with the rear surface 51a of the fixed wheel 5, and is configured to measure the radial strain in the radial direction of the support member 307 as a measurement value corresponding to the deflection of the thrust support part 51.

[0086] The control unit 101 acquires the deflection of the thrust support unit 51 based on the measurement value of the radial strain sensor 309, and performs control to acquire the magnitude of the thrust acting on the swivel base bearing 3 based on the acquired deflection of the thrust support unit 51.

[0087] As described above, the radial strain sensor 309 directly acquires the radial strain in the radial direction of the support member 307 as a measurement value. The control unit 101 obtains the relationship between the magnitude of the thrust acting on the swivel table bearing 3 and the radial strain measured by the radial strain sensor 309 by performing a predetermined structural analysis and calibrating the results of actual load measurement. Using this obtained relationship, the control unit 101 obtains (estimates) the magnitude of the thrust acting on the swivel table bearing 3 from the radial strain measured by the radial strain sensor 309.

[0088] The other configurations of the third embodiment are the same as those of the first embodiment.

[0089] (Effects of the third embodiment) In the third embodiment, the following effects can be obtained.

[0090] As described above, the third embodiment includes a support member 307 that supports, from the rear, the fixed wheel 5 that rotatably supports the rotating wheel 4 via the rear thrust roller 6c, and a deflection acquisition sensor (radial strain sensor 309) that is provided on the support member 307 and arranged opposite the rear surface 51a of the thrust support part 51 of the fixed wheel 5 that is pressed rearward by the rear thrust roller 6c, and that acquires the deflection of the thrust support part 51 that changes depending on the magnitude of the thrust acting on the swivel base bearing 3. As a result, the thrust acting on the swivel base bearing 3 can be acquired with high accuracy, similar to the first embodiment.

[0091] In the third embodiment, as described above, on the side where the radial deflection acquisition sensor of the swivel table bearing 3 is disposed, the rear surface 51a of the thrust support portion 51 of the fixed wheel 5 abuts against the front surface 371 of the support member 307, and the deflection acquisition sensor is disposed in contact with the rear surface 51a of the fixed wheel 5 and includes a radial strain sensor 309 that measures radial strain in the radial direction of the support member 307 as a measurement value corresponding to the deflection of the thrust support portion 51. This allows the radial strain sensor 309 to be disposed in contact with the rear surface 51a of the fixed wheel 5. Therefore, in a tunnel boring machine or the like that is relatively large and requires high rigidity, the deflection of the thrust support portion 51 of the fixed wheel 5 can be acquired without providing a gap between the fixed wheel 5 and the support member 307, which would reduce rigidity.

[0092] Other effects of the third embodiment are the same as those of the first embodiment.

[0093] [Fourth embodiment] A fourth embodiment will be described with reference to Fig. 16. Unlike the first embodiment that includes a swivel base bearing 3 with a drive system in which the inner ring rotates and the outer ring is fixed, this fourth embodiment will describe an example that includes a swivel base bearing 403 with a drive system in which the outer ring rotates and the inner ring is fixed. Note that in the drawing, the same components as those in the first embodiment are designated by the same reference numerals.

[0094] As shown in FIG. 16, a tunnel boring machine 400 according to the fourth embodiment is equipped with a swivel base bearing 403 of a drive type in which the outer ring rotates and the inner ring is fixed.

[0095] The swivel base bearing 403 includes a rotating ring 404 as an outer ring, a fixed ring 405 as an inner ring, a radial roller 6a, a front thrust roller 6b, and a rear thrust roller 6c arranged behind the front thrust roller 6b. The outer periphery of the rotating ring 404 is provided with external teeth 440 that mesh with an output gear (not shown) of a drive motor.

[0096] Unlike the first embodiment, the fixing member 52 is disposed on the inner cylinder 8 side in the radial direction (direction R). Therefore, the degree to which the support member 7 is deformed by the load from the inner cylinder 8 is smaller than in the first embodiment. In other words, the degree to which the size of the gap S changes due to the load from the inner cylinder 8 is smaller than in the first embodiment. It is expected that the size of the gap S will decrease due to the load from the inner cylinder 8, but even in this case, by performing a predetermined correction, it is possible to improve the accuracy of determining the thrust acting on the swivel base bearing 403.

[0097] The other configurations of the fourth embodiment are the same as those of the first embodiment.

[0098] (Effects of the fourth embodiment) In the fourth embodiment, the following effects can be obtained.

[0099] As described above, the fourth embodiment includes the support member 7 that supports, from the rear, the fixed wheel 405 that rotatably supports the rotating wheel 404 via the rear thrust roller 6c, and a deflection acquisition sensor (distance sensor 9) that is provided on the support member 7 and arranged opposite the rear surface 51a of the thrust support part 51 of the fixed wheel 405 that is pressed rearward by the rear thrust roller 6c, and that acquires the deflection of the thrust support part 51 that changes depending on the magnitude of the thrust acting on the swivel base bearing 403. As a result, the thrust acting on the swivel base bearing 403 can be acquired with high accuracy, just like the first embodiment.

[0100] Other effects of the fourth embodiment are the same as those of the first embodiment.

[0101] [Variations] The embodiments and modifications disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims rather than the description of the above embodiments, and further includes all modifications (modifications) within the meaning and scope of the claims.

[0102] For example, in the above first to fourth embodiments, an example was shown in which the present invention was applied to a mud pressure type tunnel boring machine, but the present invention is not limited to this. The present invention may also be applied to a mud water type tunnel boring machine.

[0103] In the first, second, and fourth embodiments, a step is provided on the support member to form a gap between the fixed ring and the support member, but the present invention is not limited to this. In the present invention, a step may be provided on the fixed ring to form a gap between the fixed ring and the support member. Note that a step may be provided on both the fixed ring and the support member.

[0104] In addition, in the first to fourth embodiments, an example in which eight deflection obtaining sensors of the present invention are provided is shown, but the present invention is not limited to this. In the present invention, only one deflection obtaining sensor of the present invention or a plurality of sensors other than eight may be provided.

[0105] Furthermore, in the first and fourth embodiments, examples have been shown in which the distance sensor is configured as a non-contact eddy current displacement sensor, but the present invention is not limited to this. In the present invention, the distance sensor may be configured as a contact sensor. For example, the distance sensor may be a contact type distance sensor having a movable plunger whose tip is held in contact with the rear surface of the thrust support part of the fixed ring. The plunger moves in accordance with the deflection of the thrust support part of the fixed ring so as to maintain contact with the rear surface of the thrust support part.

[0106] In the third embodiment, the radial strain sensor is disposed at the location where the fixed ring and the support member are in contact with each other, but the present invention is not limited to this. In the present invention, the radial strain sensor may be disposed at the location where the fixed ring and the support member are spaced apart, as in the first and second embodiments.

[0107] Furthermore, the control for acquiring the magnitude of the thrust acting on the swivel table bearing is not limited to the control described in the first to fourth embodiments. For example, the control unit may acquire the magnitude of the thrust acting on the swivel table bearing based on a predetermined table that indicates the relationship between the measurement value of the deflection acquisition sensor and the magnitude of the thrust acting on the swivel table bearing. [Explanation of symbols]

[0108] 1 cutter head 3, 403 Swivel bearing 4, 404 rotating wheel 5, 405 Fixed wheel 6c Rear thrust roller (thrust roller) 7, 307 Support member 8 Inner cylinder 8a Inner cylinder pressure sensor 9. Distance sensor (deflection sensor) 21a Inner partition wall 51 (Fixed wheel) thrust support 51a (Rear surface of thrust support of fixed wheel) 71 (of supporting member) front 100, 200, 300, 400 Tunnel Boring Machine 101 Control section 209 Load cell (deflection sensor) 309 Radial strain sensor (deflection sensor) C Chamber S Gap

Claims

1. a swivel bearing including a rotating ring attached to the cutter head and rotating together with the cutter head, a thrust roller, and a fixed ring rotatably supporting the rotating ring via the thrust roller; a support member that supports the fixed wheel from behind; a deflection acquisition sensor that is provided on the support member and positioned opposite the rear surface of the thrust support portion of the fixed wheel that is pressed rearward by the thrust roller, and that acquires the deflection of the thrust support portion that changes depending on the magnitude of the thrust acting on the swivel bearing.

2. 2. The tunnel boring machine according to claim 1, further comprising a control unit that acquires the deflection of the thrust support part based on the measurement value of the deflection acquisition sensor, and performs control to acquire the magnitude of the thrust acting on the swivel table bearing based on the acquired deflection of the thrust support part.

3. an inner cylinder including an inner circumferential partition wall that defines a chamber on the inner circumferential side of the swivel base bearing and is supported by the support member; an inner cylinder pressure sensor provided in the inner circumferential partition wall portion and configured to measure pressure exerted on the inner cylinder by soil and groundwater in the chamber; 3. The tunnel boring machine according to claim 2, wherein the control unit performs control to remove disturbances that the pressure measured by the inner cylinder pressure sensor causes to the measurement value of the deflection obtaining sensor.

4. 2. A tunnel boring machine as described in claim 1, wherein, in the radial direction of the swivel base bearing, the fixed ring is fixed to the support member on the opposite side to the rotating ring, and the deflection acquisition sensor is arranged opposite the rotating ring near the rotating ring.

5. a gap of a predetermined width is provided between the rear surface of the thrust support portion of the fixed ring and the front surface of the support member on a side of the swivel base bearing on which the deflection acquisition sensor is disposed in the radial direction when no load is applied to the cutter head, the gap being spaced apart in the front-rear direction; 5. The tunnel boring machine according to claim 4, wherein the deflection obtaining sensor includes a distance sensor that measures the size of the gap as a measurement value corresponding to the deflection of the thrust support section.

6. 6. The tunnel boring machine according to claim 5, wherein the distance sensor is an eddy current displacement sensor arranged opposite the rear surface across the gap.

7. a gap of a predetermined width is provided between the rear surface of the fixed ring and the front surface of the support member on a side of the swivel base bearing where the deflection acquisition sensor is disposed in the radial direction, when no load is applied to the cutter head; 5. The tunnel boring machine according to claim 4, wherein the deflection acquisition sensor includes a load cell that measures a compressive force that changes with the size of the gap as a measurement value corresponding to the deflection of the thrust support part.

8. the rear surface of the thrust support portion of the fixed ring abuts against the front surface of the support member on a side of the swivel base bearing where the deflection acquisition sensor is disposed in the radial direction, 5. A tunnel boring machine as described in claim 4, wherein the deflection acquisition sensor includes a radial strain sensor that is arranged in contact with the rear surface of the fixed wheel and measures radial strain in the radial direction of the support member as a measurement value corresponding to the deflection of the thrust support part.

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