Tunnel Boring Machines and Cutter Bits

Abstract

To provide a tunnel excavator and a cutter bit allowing excavation tips to be prevented from dropping out from a base material.SOLUTION: A tunnel excavator is provided with: a cutter bit 3 including excavation tips 5 and a base material 4 on which the excavation tips 5 are connected; and a cutter head having the cutter bit 3 provided on its front surface and excavating forward with its rotation, wherein the base material 4 comprises: a first support wall 41 extending along a radial direction of the cutter head when viewed from the front side in an excavation direction of the cutter head and supporting the excavation tips 5; and a second support wall 42 extending along a circumferential direction of the cutter head when viewed from the front side in the excavation direction of the cutter head and supporting the excavation tips 5.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a tunnel boring machine and a cutter bit, and more particularly to a tunnel boring machine and a cutter bit comprising a drilling tip and a base material to which the drilling tip is bonded. [Background technology]

[0002] 2. Description of the Related Art Conventionally, cutter bits including a drilling tip and a base material to which the drilling tip is joined are known (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses a cutter bit including a tip and a base material to which the tip is joined. The cutter bit is provided on a cutter face of an excavator that excavates natural ground. The base material of the cutter bit has a plurality of support walls that support the tip. The plurality of support walls extend in the radial direction of the cutter face and are arranged in the circumferential direction of the cutter face when viewed from the front side in the excavation direction of the excavator. That is, the base material is formed in a comb-teeth shape that extends in the radial direction of the cutter face. The cutter bit supports the tip by the comb-teeth-shaped base material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-241681 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the comb-tooth cutter bit extending in the radial direction of the cutter face described in Patent Document 1, the tip is supported only by the support wall extending in the radial direction of the cutter face. Therefore, when a force of soil or sand in the radial direction of the cutter face along the support wall is applied to the tip during excavation, the tip may fall off from the base material, and therefore it has been desired to prevent the tip from falling off from the base material of the cutter bit.

[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 and a cutter bit that are capable of preventing the drilling tip from falling off from the base material. [Means for solving the problem]

[0007] In order to achieve the above object, a tunnel boring machine of the present invention comprises a cutter bit including a boring tip and a base material to which the boring tip is joined, and a cutter head on which the cutter bit is installed at the front and excavates as it rotates, the base material having a first support wall which extends along the radial direction of the cutter head when viewed from the front side in the excavation direction of the cutter head and supports the boring tip, and a second support wall which extends along the circumferential direction of the cutter head when viewed from the front side in the excavation direction of the cutter head and supports the boring tip. The first support wall and the second support wall overlap with the excavation tip so that the excavation tip does not protrude forward when viewed from a direction perpendicular to the front-rear direction. .

[0008] In the tunnel boring machine of the present invention, as described above, the base material is provided with a first support wall that extends along the radial direction of the cutter head when viewed from the front side of the excavation direction of the cutter head and supports the excavation tip, and a second support wall that extends along the circumferential direction of the cutter head when viewed from the front side of the excavation direction of the cutter head and supports the excavation tip. In this way, when a force in the circumferential direction of the cutter head is applied to the cutter bit, the excavation tip can be supported by the first support wall, and when a force in the radial direction of the cutter head is applied to the cutter bit, the excavation tip can be supported by the second support wall extending along the circumferential direction of the cutter head. That is, it is possible to prevent the excavation tip from falling off the base material. In addition, since the excavation tip can be supported not only by the first support wall but also by the second support wall in addition to the first support wall, the strength of the cutter bit in which the excavation tip is joined to the base material can be improved.

[0009] In the above tunnel boring machine, the second support wall is preferably connected to the first support wall so as to be substantially perpendicular to the first support wall. With this configuration, the second support wall substantially perpendicular to the first support wall is connected to the first support wall, so that the force applied to the second support wall can be effectively dispersed to the first support wall as well. As a result, the strength of the cutter bit having the drilling tip joined to the base material can be improved while preventing the drilling tip from falling off the base material.

[0010] In the above tunnel boring machine, preferably, a plurality of first support walls are provided in a line along the circumferential direction of the cutter head, and the second support wall connects one adjacent first support wall to the other adjacent first support wall. With this configuration, both ends of the second support wall are connected to the first support wall in the circumferential direction of the cutter head, so that the force applied to the second support wall can be more effectively distributed to the first support wall. As a result, it is possible to further improve the strength of the cutter bit in which the drilling tip is joined to the base material while preventing the drilling tip from falling off the base material.

[0011] In the above tunnel boring machine, the boring tip preferably has an inner tip arranged on the radially inner side of the cutter head with respect to the second support wall, and an outer tip arranged on the radially outer side of the cutter head with respect to the second support wall. With this configuration, both the inner tip and the outer tip can be supported by the second support wall regardless of whether a force toward the radially inner side of the cutter head or a force toward the radially outer side of the cutter head is applied to the cutter head.

[0012] In the above tunnel boring machine, the base material preferably further has a base portion that holds the first support wall and the second support wall from the rear side in the excavation direction of the cutter head, and the base portion includes a first base portion that holds the first support wall from the rear side, and a second base portion that is formed smaller than the first base portion in the radial direction of the cutter head, is arranged forward of the first base portion in the excavation direction of the cutter head, and holds the first support wall and the second support wall from the rear side. With this configuration, the forward protrusion length of the cantilevered second support wall that protrudes forward from the second base portion by the second base portion can be shortened compared to the case where the second support wall is supported by the first base portion. Therefore, the deformation of the second support wall due to a force directed toward the inner periphery side in the radial direction of the cutter head can be reduced. As a result, the strength of the cutter bit in which the drilling tip is joined to the base material can be further improved.

[0013] In this case, preferably, the second base is covered by the excavation tip from the front side in the excavation direction of the cutter head. With this configuration, the second base is covered by the excavation tip, so that the second base can be protected from wear.

[0014] The cutter bit of the present invention includes a drilling tip and a base material to which the drilling tip is joined. The base material includes a first support wall that extends along the short direction of the base material and supports the drilling tip, and a second support wall that extends along the long direction of the base material and supports the drilling tip. The first support wall and the second support wall overlap with the excavation tip so that the excavation tip does not protrude forward when viewed from a direction perpendicular to the front-rear direction. The "short side" and "long side" of the base material refer to the short side and long side of the base material when the cutter bit is viewed from the protruding side of the cutter bit, that is, the front side of the cutter head, when the cutter bit is installed in the cutter head.

[0015] In the cutter bit of the present invention, as described above, the base material is provided with a first support wall that extends along the short side direction of the base material and supports the drilling tip, and a second support wall that extends along the long side direction of the base material and supports the drilling tip. In this way, when a force in the long side direction of the base material is applied to the cutter bit, the first support wall can support the drilling tip, and when a force in the short side direction of the base material is applied to the cutter bit, the second support wall that extends along the long side direction of the base material can support the drilling tip. That is, it is possible to prevent the drilling tip from falling off the base material. In addition, since the drilling tip can be supported not only by the first support wall but also by the second support wall in addition to the first support wall, the strength of the cutter bit in which the drilling tip is joined to the base material can be improved. Effect of the Invention

[0016] According to the present invention, as described above, it is possible to prevent the drilling tip from falling off from the base material. [Brief description of the drawings]

[0017] [Figure 1] FIG. 2 is a longitudinal sectional view of a tunnel boring machine according to an embodiment. [Diagram 2] FIG. 2 is a front view of a tunnel boring machine according to an embodiment, as viewed from the front side in the excavation direction. [Diagram 3] FIG. 2 is a perspective view of a cutter bit according to an embodiment. [Figure 4] FIG. 2 is a perspective view of a base material of a cutter bit according to an embodiment, as viewed from the inner peripheral side of a cutter head. [Diagram 5] FIG. 2 is a perspective view of a base material of a cutter bit according to an embodiment, as viewed from the outer periphery side of a cutter head. [Figure 6] FIG. 2 is an exploded perspective view of a cutter bit according to an embodiment. [Figure 7] 1A is an oblique view of a modified cutter bit, FIG. 1B is an oblique view of the base material of the modified cutter bit from the inner peripheral side of the cutter head, and FIG. 1C is an oblique view of the base material of the modified cutter bit from the outer peripheral side of the cutter head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

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

[0019] [Embodiment] A tunnel boring machine 100 of an embodiment will be described with reference to Figs. 1 to 6.

[0020] (Overall configuration of the tunnel boring machine) As shown in FIG. 1, a tunnel boring machine 100 comprises a boring machine body 1, a cutter head 2 installed at the tip of the boring machine body 1 in the excavation direction, and a plurality of cutter bits 3 installed on the cutter head 2.

[0021] Here, in each figure, the forward direction of the tunnel boring machine 100 in the excavation direction is indicated by the X1 direction, and the opposite direction is indicated by the X2 direction. The radial direction of the cutter head 2 is indicated by the RA direction. The direction from the inner circumference side to the outer circumference side in the RA direction is indicated by the RA1 direction, and the direction from the outer circumference side to the inner circumference side in the RA direction is indicated by the RA2 direction. It is also indicated by the circumferential direction RO of the cutter head 2. The axis located at the center of the cutter head 2 is indicated by the central axis α. The radial direction of the cutter head 2 is also the short direction of the base material 4 (cutter bit 3). The circumferential direction of the cutter head 2 is also the longitudinal direction of the base material 4 (cutter bit 3). The "short direction" and "longitudinal direction" of the base material 4 refer to the short direction and long direction of the base material 4 when the cutter bit 3 is installed in the cutter head 2 and the cutter bit 3 is viewed from the side from which the cutter bit 3 protrudes, i.e., the front side of the cutter head 2.

[0022] The cutter head 2 is configured to move forward in the excavation direction as it rotates around a central axis α of the cutter head 2 extending in the excavation direction, thereby excavating the natural ground. The rotation of the cutter head 2 is configured to be switchable between forward and reverse rotation depending on the excavation conditions, etc.

[0023] In this embodiment, an example is shown in which the tunnel boring machine 100 is configured as a mud pressure type boring machine.

[0024] (Excavator body configuration) As shown in FIG. 1, the excavator body 1 includes a trunk 10, a chamber 11, a propulsion jack 12, and an earth removal device 13.

[0025] The fuselage 10 is composed of a forward section 10a and a rear section 10b. A cutter head 2 is installed at the front end of the forward section 10a in the excavation direction. The rear section 10b is the section that advances while arranging segments SG on the wall surface by an erector (not shown) to form the circumferential wall of the tunnel as the forward section 10a excavates. The internal space of the fuselage 10 is divided by a partition wall 14 into two spaces: a chamber 11 on the excavation direction side and a working space WS behind the chamber 11.

[0026] The chamber 11 is provided on the rear side (X2 direction side) of the cutter head 2. The chamber 11 is a space (mud working chamber) surrounded by the cutter head 2, the front body part 10a, and the partition wall 14. The mud pressure in the chamber 11 is maintained in approximate equilibrium with the pressure acting on the cutter head 2 from the natural ground side.

[0027] The propulsion jacks 12 are configured to push the segments SG rearward (in the X2 direction) to propel the body 10 (tunnel boring machine 100). A plurality of the propulsion jacks 12 are provided so as to be aligned along the circumferential direction of the body 10.

[0028] The soil discharge device 13 is configured, for example, by a screw conveyor. The front end of the soil discharge device 13 is connected to the lower side of the chamber 11. The soil discharge device 13 is configured to take in soil from the chamber 11 by rotating an internal screw 13a, transport it to an opening at the rear end of the soil discharge device 13, and discharge it into the work space WS. The soil discharged from the soil discharge device 13 to the work space WS is transported toward the outside of the pit by a soil transporting device (not shown) such as a belt conveyor.

[0029] (Cutter head configuration) As shown in Fig. 2, the cutter head 2 is formed in a circular shape when viewed from the excavation direction. A plurality of cutter bits 3 are installed on the front surface of the cutter head 2. The cutter bits 3 in this embodiment are so-called leading bits.

[0030] The cutter head 2 is provided with a plurality of (four) cutter spokes 20 extending radially in the radial direction of the cutter head 2. A plurality of cutter bits 3 are installed on the cutter spokes 20. The plurality of cutter bits 3 are linearly arranged along the cutter spokes 20. That is, the plurality of cutter bits 3 are arranged on the cutter spokes 20 so as to be aligned in the radial direction.

[0031] The multiple cutter bits 3 are installed on the cutter head 2 in a state where they are aligned in the same direction. In detail, the multiple cutter bits 3 are installed on the cutter head 2 in a state where the orientation of the short side direction of the cutter bit 3 approximately coincides with the radial direction of the cutter head 2 when viewed from the front in the excavation direction of the cutter head 2. The multiple cutter bits 3 are also installed on the cutter head 2 in a state where the side where the inclined surface 3a (see FIG. 3) of the cutter bit 3 is provided faces the inner peripheral side (central axis α) of the cutter head 2 when viewed from the front in the excavation direction of the cutter head 2.

[0032] The cutter head 2 is provided with a cutter drive source 21 (see FIG. 1) that applies a rotational force about a central axis α to the cutter head 2 on which the cutter bit 3 is installed. The cutter drive source 21 is formed of, for example, a hydraulic motor.

[0033] (Cutter bit configuration) As shown in Fig. 3 to Fig. 6, the cutter bit 3 includes a base material 4 and a drilling tip 5. The drilling tip 5 is joined to the base material 4. The base material 4 includes a base 40, a first support wall 41, and a second support wall 42.

[0034] The cutter bit 3 is provided with an inclined surface 3a (see FIG. 3) extending in the longitudinal direction (RO direction) of the cutter bit 3 at the end on the front side in the excavation direction of the cutter head 2 and on the inner circumferential side in the radial direction. The cutter bit 3 is also provided with a pair of inclined surfaces 3b (see FIG. 3) extending in the lateral direction (RA direction) of the cutter bit 3 at the end on the front side in the excavation direction of the cutter head 2 and on both circumferential sides. The inclined surfaces may be provided at the end on the front side in the excavation direction of the cutter head and on the outer circumferential side in the radial direction. Although the present invention illustrates a cutter bit having an inclined surface, the cutter bit does not have to have an inclined surface.

[0035] The drilling tip 5 of the cutter bit 3 and the base material 4 (the first support wall 41, the second support wall 42 and the base 40) are diffusion bonded via the insert material I by hot isostatic pressing.

[0036] (The composition of the cutter bit's "base material") As an example, the base material 4 of the cutter bit 3 is made of steel such as carbon steel for machine construction (S50C). The base material 4 is formed into a predetermined shape having projections and recesses by hot isostatic pressing, which is performed by assembling a plurality of parts having a generally rectangular parallelepiped shape. Note that the base material may be formed by machining (cutting) the steel directly without using the hot isostatic pressing.

[0037] (The composition of the "base" of the cutter bit's base material) 4 and 5, the base portion 40 of the base material 4 is supported by the cutter spokes 20. The base portion 40 includes a first base portion 40a and a second base portion 40b.

[0038] The first base portion 40a holds the first support wall 41 from the rear side (X2 direction side). The first base portion 40a is formed in a plate shape whose longitudinal direction is the circumferential direction of the cutter bit 3 and whose lateral direction is the radial direction of the cutter bit 3.

[0039] The second base 40b is disposed forward (X1 direction side) of the first base 40a in the excavation direction of the cutter head 2. The second base 40b is held from the rear side by the first base 40a. The second base 40b is directly connected to the first base 40a. The second base 40b is formed smaller than the first base 40a in the radial direction of the cutter head 2. In detail, the length L1 of the second base 40b is smaller than the length L2 of the first base 40a in the radial direction of the cutter head 2 (see FIG. 4).

[0040] A plurality of second base portions 40b are provided on both sides of the first support wall 41 in the circumferential direction of the cutter head 2 and on both sides of the second support wall 42 in the radial direction of the cutter head 2.

[0041] Each of the second bases 40b is formed in a rectangular parallelepiped (block) shape. In the radial direction of the cutter head 2, a length L10 in the front-rear direction (X direction) of the second bases 40b located between the first support walls 41 is greater than a length L11 in the front-rear direction (X direction) of the second bases 40b located outside the first support walls 41 in the radial direction of the cutter head 2 (see FIG. 4).

[0042] The second base portion 40b is covered by the excavation tip 5 from the front side in the excavation direction of the cutter head 2. That is, the second base portion 40b is disposed inside the cutter head 2 so as not to be exposed.

[0043] (Structure of the "first support wall" of the cutter bit base material) The first support wall 41 of the base material 4 extends along the radial direction of the cutter head 2 when viewed from the front side in the excavation direction of the cutter head 2. That is, the first support wall 41 is a plate-shaped wall portion that extends in the excavation direction and the front-rear direction of the cutter head 2 and has a thickness direction in the circumferential direction of the cutter head 2. Moreover, the base material 4 including the first support wall 41 is formed in a shape that overlaps substantially the entire excavation tip 5 when viewed from the circumferential direction of the cutter head 2.

[0044] A plurality of (three) first support walls 41 are provided so as to be aligned along the circumferential direction of the cutter head 2. The plurality of first support walls 41 have substantially the same shape as each other.

[0045] The front end face (X1 direction) and both end faces in the radial direction (RA direction) of the first support wall 41 are not covered by the drilling tip 5 and are exposed.

[0046] (Configuration of the "second support wall" of the cutter bit base material) The second support wall 42 is connected to the first support wall 41 so as to be substantially perpendicular to the first support wall 41 .

[0047] The second support wall 42 of the base material 4 extends along the circumferential direction of the cutter head 2 when viewed from the front side in the excavation direction of the cutter head 2. In other words, the second support wall 42 is a plate-shaped wall portion that extends in the circumferential direction and the front-rear direction of the cutter head 2 and has a thickness direction in the radial direction of the cutter head 2.

[0048] The second support wall 42 is disposed between one adjacent first support wall 41 and the other adjacent first support wall 41. The second support wall 42 connects one adjacent first support wall 41 and the other adjacent first support wall 41. In addition, between the adjacent first support walls 41, the base material 4 including the second support wall 42 is formed in a shape that overlaps substantially the entirety of the drilling tip 5 when viewed from the radial direction of the cutter head 2.

[0049] The front (X1 direction) end face of the second support wall 42 is not covered by the drilling tip 5 and is exposed.

[0050] (The composition of the cutter bit's "drilling tip") As an example, the drilling tip 5 shown in Fig. 3 and Fig. 6 is made of cemented carbide. The drilling tip 5 is made up of a plurality of parts having a generally rectangular parallelepiped shape.

[0051] The drilling tip 5 has an inner tip 5a that is arranged on the radially inner side of the cutter head 2 relative to the second support wall 42, and an outer tip 5b that is arranged on the radially outer side of the cutter head 2 relative to the second support wall 42.

[0052] The inner peripheral tip 5a and the outer peripheral tip 5b are sandwiched between first support walls 41 from both sides in the circumferential direction of the cutter head 2.

[0053] (Cutter bit manufacturing) The manufacture of the cutter bit 3 will now be described.

[0054] First, as shown in Fig. 4 and Fig. 5, a plurality of steel parts forming the base material 4 are assembled. Next, the insert material I is placed along the boundary between the base material 4 and the drilling tip 5. At this time, the second base portion 40b is covered with the insert material I.

[0055] Next, as shown in FIG. 6, a plurality of cemented carbide parts forming a drilling tip 5 are attached to the base material 4 and the insert material I.

[0056] Next, the unbonded base material 4, the insert material I, and the drilling tip 5 are placed in a heating and pressurizing furnace (not shown) for performing hot isostatic pressing (HIP) treatment, and are heated and pressurized to diffusion bond the base material 4, the insert material I, and the drilling tip 5. The heating and pressurizing furnace is filled with an inert gas such as argon gas.

[0057] The base material 4 and the drilling tip 5, which are made of different materials, are joined more firmly by the insert material I than when the base material 4 and the drilling tip 5 are directly joined. Note that hot isostatic pressing (HIP) is also called hot isostatic pressing.

[0058] The front end faces of the first support wall 41 and the second support wall 42 of the cutter bit 3 and all of the drilling tips 5 located in front of the cutter bit 3 have a measurement plane M1 perpendicular to the front-rear direction (X direction). The measurement plane M1 is a plane parallel to a reference plane M2, which is the rear end face of the cutter bit 3. The reference plane M2 is a plane that serves as a reference for positioning the cutter bit 3 when measuring dimensions to confirm the accuracy of the cutter bit 3.

[0059] (Effects of the embodiment) In this embodiment, the following effects can be obtained.

[0060] In this embodiment, as described above, the base material 4 is provided with a first support wall 41 that extends along the radial direction of the cutter head 2 when viewed from the front side of the excavation direction of the cutter head 2 and supports the drilling tip 5, and a second support wall 42 that extends along the circumferential direction of the cutter head 2 when viewed from the front side of the excavation direction of the cutter head 2 and supports the drilling tip 5. In this way, when a force in the circumferential direction of the cutter head 2 is applied to the cutter bit 3, the drilling tip 5 can be supported by the first support wall 41, and when a force in the radial direction of the cutter head 2 is applied to the cutter bit 3, the drilling tip 5 can be supported by the second support wall 42 extending along the circumferential direction of the cutter head 2. That is, it is possible to prevent the drilling tip 5 from falling off the base material 4. In addition, since the drilling tip 5 can be supported not only by the first support wall 41 but also by the second support wall 42 in addition to the first support wall 41, the strength of the cutter bit 3 in which the drilling tip 5 is joined to the base material 4 can be improved.

[0061] In this embodiment, as described above, the second support wall 42 is connected to the first support wall 41 so as to be approximately perpendicular to the first support wall 41. As a result, the second support wall 42, which is approximately perpendicular to the first support wall 41, is connected to the first support wall 41, so that the force applied to the second support wall 42 can be effectively dispersed to the first support wall 41 as well. As a result, the strength of the cutter bit 3 in which the drilling tip 5 is joined to the base material 4 can be further improved while preventing the drilling tip 5 from falling off from the base material 4.

[0062] In this embodiment, as described above, a plurality of first support walls 41 are provided so as to be aligned along the circumferential direction of the cutter head 2, and the second support wall 42 connects one adjacent first support wall 41 to the other adjacent first support wall 41. As a result, both ends of the second support wall 42 are connected to the first support wall 41 in the circumferential direction of the cutter head 2, so that the force applied to the second support wall 42 can be more effectively distributed to the first support wall 41. As a result, the strength of the cutter bit 3 in which the drilling tip 5 is joined to the base material 4 can be further improved while preventing the drilling tip 5 from falling off from the base material 4.

[0063] In this embodiment, as described above, the excavation tip 5 has the inner tip 5a arranged on the radially inner side of the cutter head 2 with respect to the second support wall 42, and the outer tip 5b arranged on the radially outer side of the cutter head 2 with respect to the second support wall 42. This makes it possible to support both the inner tip 5a and the outer tip 5b by the second support wall 42 even if a force toward the radially inner side of the cutter head 2 or a force toward the radially outer side of the cutter head 2 is applied to the cutter head 2.

[0064] In this embodiment, as described above, the base material 4 further includes a base 40 that holds the first support wall 41 and the second support wall 42 from the rear side in the excavation direction of the cutter head 2, and the base 40 includes a first base 40a that holds the first support wall 41 from the rear side, and a second base 40b that is formed smaller than the first base 40a in the radial direction of the cutter head 2, is arranged forward of the first base 40a in the excavation direction of the cutter head 2, and holds the first support wall 41 and the second support wall 42 from the rear side. This makes it possible to shorten the forward protruding length of the cantilevered second support wall 42 that protrudes forward from the second base 40b by the second base 40b, compared to the case in which the second support wall is supported by the first base. Therefore, it is possible to reduce the deformation of the second support wall 42 due to a force directed toward the inner periphery in the radial direction of the cutter head 2. As a result, the strength of the cutter bit 3 in which the drilling tip 5 is joined to the base material 4 can be further improved.

[0065] In this embodiment, as described above, the second base 40b is covered by the drilling tip 5 from the front side in the excavation direction of the cutter head 2. As a result, since the second base 40b is covered by the drilling tip 5, the second base 40b can be protected from wear. It is preferable that the second base 40b contacts at least one of the first support wall 41 and the second support wall 42, and more preferably contacts both the first support wall 41 and the second support wall 42. Specifically, the second base 40b contacts the first support wall 41 in the longitudinal direction (RO direction) of the cutter bit 3, and contacts the second support wall 42 in the lateral direction (RA direction) of the cutter bit 3. In these cases, the second base 40b plays a role of supporting the first support wall 41 and the second support wall 42, and the forward protruding length of the first support wall 41 and the second support wall 42 as a cantilever beam supporting the drilling tip 5 can be shortened. Therefore, deformation of the first support wall 41 and the second support wall 42 can be reduced, and as a result, the strength of the cutter bit 3 in which the drilling tip 5 is joined to the base material 4 can be further improved.

[0066] [Variations] The embodiments and modifications disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (modifications) within the meaning and scope equivalent to the claims.

[0067] For example, in the above embodiment, an example was shown in which the second support wall was provided only between adjacent first support walls in the radial direction of the cutter head, but the present invention is not limited to this. In the present invention, the second support wall may also be provided outside the first support wall, not sandwiched between adjacent first support walls, in the radial direction of the cutter head. Note that in the present invention, the base material may be configured such that one of the first support wall and the second support wall penetrates the other of the first support wall and the second support wall, or the first support wall and the second support wall may be configured integrally.

[0068] In the above embodiment, an example in which three first support walls are provided is shown, but the present invention is not limited to this. In the present invention, a number of first support walls other than three may be provided.

[0069] In the above embodiment, the base material includes the second base portion, but the present invention is not limited to this. In the present invention, the base material does not necessarily have to include the second base portion.

[0070] In the above embodiment, the base material and the drilling tip are joined by hot isostatic pressing (HIP), but the present invention is not limited to this. In the present invention, the base material and the drilling tip may be joined by other methods such as brazing. When brazing is used, as shown in Figs. 7(A) to (C), the base material 204 of the cutter bit 203 is formed into a relatively simple shape with few projections and recesses without providing a second base portion on the base material 204 (formed into a simpler shape than the embodiment). Therefore, the number of drilling tips 205 is relatively small (less than the embodiment).

[0071] In the above embodiment, the tunnel boring machine of the present invention is configured as a mud pressure type boring machine, but the present invention is not limited to this. In the present invention, the tunnel boring machine may be configured as a mud water type boring machine.

[0072] In the above embodiment, the cutter bit of the present invention is configured by a leading bit, but the present invention is not limited to this. In the present invention, the cutter bit may be configured by a type of bit other than the leading bit, such as a teeth bit. [Explanation of symbols]

[0073] 2 Cutter Head 3, 203 Cutter Bit 4, 204 Base material 5, 205 Drilling tip 5a Inner Chip 5b Periphery Chip 40 base 40a 1st base 40b 2nd base 41 1st support wall 42 Second support wall 100 Tunnel Boring Machine

Claims

1. A cutter bit including a drilling tip and a base material to which the drilling tip is joined; A cutter head on which the cutter bit is installed at the front and which excavates as it rotates; The base material is A first support wall that extends along a radial direction of the cutter head when viewed from the front side in the excavation direction of the cutter head and supports the excavation tip; A second support wall extends along the circumferential direction of the cutter head when viewed from the front side in the excavation direction of the cutter head and supports the excavation tip, A tunnel boring machine, wherein the first support wall and the second support wall overlap the excavation tip so that the excavation tip does not protrude forward when viewed in a direction perpendicular to the front-to-rear direction.

2. 2. The tunnel boring machine of claim 1, wherein the second support wall is connected to the first support wall so as to be substantially perpendicular to the first support wall.

3. The first support wall is provided in a plurality of positions aligned along the circumferential direction of the cutter head, 3. The tunnel boring machine according to claim 1, wherein the second support wall connects one of the first support walls and the other of the first support walls adjacent to each other.

4. The drilling tip is an inner peripheral tip disposed on a radially inner peripheral side of the cutter head with respect to the second support wall; The tunnel boring machine according to any one of claims 1 to 3, further comprising: an outer circumferential tip arranged on the radially outer circumferential side of the cutter head relative to the second support wall.

5. The base material further has a base that holds the first support wall and the second support wall from the rear side in the excavation direction of the cutter head, The base portion is a first base portion that holds the first support wall from a rear side; A tunnel boring machine as described in any one of claims 1 to 4, including a second base that is formed smaller than the first base in the radial direction of the cutter head, is positioned further forward than the first base in the excavation direction of the cutter head, and holds the first support wall and the second support wall from the rear side.

6. 6. The tunnel boring machine according to claim 5, wherein the second base portion is covered by the excavation tip from a front side in an excavation direction of the cutter head.

7. A drilling tip; A base material to which the drilling tip is joined, The base material is A first support wall extending along a short direction of the base material and supporting the drilling tip; A second support wall extending along the longitudinal direction of the base material and supporting the drilling tip; The cutter bit, wherein the first support wall and the second support wall overlap the drilling tip so that the drilling tip does not protrude forward when viewed in a direction perpendicular to the front-rear direction.

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