Cutter bit

Abstract

To provide a cutter bit that reduces abrasion and is impact-resistant.SOLUTION: A cutter bit comprises: a base material that can be attached to a rotary section of a drilling machine; and a bit that is attached to the base material, has an end part facing a working face with which the drilling machine drills, and is harder than the base material. The end part extends in a rotation direction of the rotary section, and is formed in circular arc shape to protrude toward the working face.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a cutter bit. [Background technology]

[0002] 2. Description of the Related Art A tunnel boring machine equipped with a cutter bit is known in the prior art (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 11-166390 Summary of the Invention [Problem to be solved by the invention]

[0004] In the prior art, it has been difficult to reduce wear on the cutter bit while also providing impact resistance.

[0005] In view of the above circumstances, the present invention aims to provide a cutter bit that reduces wear and has impact resistance. [Means for solving the problem]

[0006] In one aspect, the present invention provides a cutter bit comprising a base material that can be attached to a rotating part of an excavator, and a bit that is attached to the base material and has an end facing a face excavated by the excavator, the bit having a hardness greater than that of the base material, wherein the end extends in the rotational direction of the rotating part and is formed in an arc shape that protrudes toward the face when viewed in the radial direction of the rotating part. Effect of the Invention

[0007] With the above-described configuration, it is possible to provide a cutter bit that has reduced wear and is impact resistant. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a cross-sectional view of a tunnel boring machine according to a first embodiment. [Diagram 2] FIG. 1 is a front view of a tunnel boring machine according to a first embodiment. [Diagram 3] 1A is a front view of a cutter bit according to a first embodiment, FIG. 1B is a side view seen in a radial direction of a cutter head, and FIG. 1C is a side view seen in a rotation direction of the cutter head. [Figure 4] 13A is a front view of a cutter bit according to a second embodiment, FIG. 13B is a side view seen in a radial direction of a cutter head, and FIG. 13C is a side view seen in a rotation direction of the cutter head. [Diagram 5] 13A is a front view of a cutter bit according to a third embodiment, FIG. 13B is a side view seen in a radial direction of a cutter head, and FIG. 13C is a side view seen in a rotation direction of the cutter head. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] First Embodiment A tunnel boring machine 1, which is one embodiment of a tunnel boring machine according to the present invention, will be described below. As shown in Fig. 1, the tunnel boring machine 1 is a device for boring a tunnel, and excavates the ground in a direction from the tunnel entrance toward the tunnel face E as the excavation direction. In the following, the tunnel boring machine 1 and the components that constitute it will be described with the face E side as the front and the tunnel entrance side as the rear. For removable components and devices, the directions such as front and rear will be defined and described based on the attached state as a general rule.

[0010] The tunnel boring machine 1 comprises a cutter head 2, a main body 3 that rotationally drives the cutter head 2 in a rotational direction (FIG. 2), and a cutter bit 4 attached to the cutter head 2. By rotationally driving the cutter head 2, the tunnel boring machine 1 can excavate the ground using the cutter bit 4.

[0011] The cutter head 2 has a generally annular or generally circular outer shape when viewed from the front, and is supported rotatably about an axis 2C by the main body 3. The cutter bit 4 is welded to the cutter head 2 in this embodiment, but may be attached to the cutter head 2 via a member such as a holder.

[0012] The main body 3 is disposed behind the cutter head 2 (FIG. 1). The main body 3 supports the cutter head 2 rotatably about an axis 2C. The main body 3 mainly includes a motor 31, a screw conveyor 32, and a plurality of segments 33.

[0013] The motor 31 is connected to the cutter head 2 via a reduction gear mechanism, and can rotate the cutter head 2. The screw conveyor 32 has the function of transporting rearward the soil and sand generated during excavation of the face E. At the rear of the main body 3, the inner circumferential surface of the excavated hole is covered with segments 33 as the excavation progresses, and the inner wall of the tunnel is constructed.

[0014] The cutter bit 4 is a metal excavation tool formed into a roughly plate shape, and is fixed to the cutter head 2 so as to extend in the rotational direction and the front-rear direction (Figs. 1 and 2). The front part of the cutter bit 4 is formed into a wedge shape that becomes thinner toward the front (Fig. 3(c)), and is formed into a roughly rectangular shape when viewed in the radial direction of the cutter head 2 (Fig. 3(b)).

[0015] The cutter bit 4 includes a base material 41, a bit 42 fixed to the front part of the base material 41, and a plurality of tips 43.

[0016] The base material 41 is a plate-shaped member extending in the rotational direction and forward and backward, and has a base 41A that is attached to the cutter head 2 by welding or the like, a hardening layer 41B provided in front of the base 41A, and two side portions 41C provided at the rotational end portions.

[0017] Each of the side portions 41C has a side surface portion 41D extending in the excavation direction and extending intersecting the rotational direction, and a side surface portion 41E extending intersecting the rotational direction and radial direction of the cutter head 2 (FIG. 2).

[0018] The hardfacing 41B is provided so as to form the front surface of the base material 41, as shown by hatching in FIG.

[0019] The bit 42 has a function of excavating the face E and is formed in a plate shape. The bit 42 is arranged to extend in the rotation direction, has an attitude oblique to the radial direction, and is embedded and held in the base material 41. The front end of the bit 42 protrudes from the base material 41 and is formed in an arc shape extending in the rotation direction.

[0020] The bit 42 is made of a cemented carbide alloy, and its hardness is higher than that of the base material 41. A specific example of the material of the bit 42 is JIS:E3 (Japanese Industrial Standard, JIS M3913).

[0021] <Second embodiment> A cutter bit 104 according to a second embodiment will now be described.

[0022] In the second embodiment, the reference numbers of members corresponding to those in the first embodiment are incremented by 100. Members having substantially the same configurations as those in the first embodiment are given the same reference numbers, and descriptions thereof will be omitted.

[0023] A cutter bit 104 in the second embodiment is shown in Fig. 4. The cutter bit 104 is a member that is attached to the cutter head 2 in the same manner as the cutter bit 4.

[0024] The cutter bit 104 is a metal excavating tool formed into a substantially plate shape, and is fixed to the cutter head 2 so as to extend in the rotational direction and the front-rear direction. The front part of the cutter bit 104 is formed into a wedge shape so as to become thinner toward the front (FIG. 4(c)), and is formed into a substantially rectangular shape when viewed in the radial direction of the cutter head 2 (FIG. 4(b)).

[0025] The cutter bit 104 includes a base material 41, a bit 42 fixed to the front part of the base material 41, and a plurality of tips 43.

[0026] The shape and configuration of the base material 41 and the bit 42 are similar to those of the first embodiment.

[0027] The chips 43 are formed in the shape of smaller grains than the side portions 41C, and a plurality of chips are arranged over the entire surfaces of the side portions 41D, 41E. The chips 43 are members fixed to the side portions 41D, 41E by thermally spraying synthetic diamond onto the side portions 41D, 41E. Since the chips 43 are made of synthetic diamond, they have a higher hardness than the base material 41.

[0028] Instead of artificial diamond, a cemented carbide such as tungsten carbide may be used for the tip 43. In this case, too, the material is sprayed onto the side portions 41D and 41E to form the plurality of tips 43. When a cemented carbide is used for the tip 43, it is preferable to use a material conforming to JIS: E5 or JIS: E4.

[0029] Moreover, it is preferable that the hardness of the bit 42 is higher than the hardness of the tip 43. With such a configuration, the wear resistance performance during excavation of the face E can be maintained by the bit 42 and the base material 41, and the impact resistance performance can be improved by the tip 43.

[0030] <Third embodiment> A cutter bit 204 according to a third embodiment will now be described.

[0031] In the second embodiment, the reference numbers of the members corresponding to those in the first embodiment are incremented by 200. The same reference numbers are used for members having substantially the same configurations as those in the first embodiment, and descriptions thereof will be omitted.

[0032] A cutter bit 204 in the second embodiment is shown in Fig. 5. The cutter bit 204 is a member that is attached to the cutter head 2 in the same manner as the cutter bit 4.

[0033] The cutter bit 204 is a metal excavating tool formed into a substantially plate shape, and is fixed to the cutter head 2 so as to extend in the rotational direction and the front-rear direction. The front part of the cutter bit 204 is formed into a wedge shape so as to become thinner toward the front (FIG. 5(c)), and is formed into a substantially rectangular shape when viewed in the radial direction of the cutter head 2 (FIG. 5(b)).

[0034] The cutter bit 204 includes a base material 41, a bit 42 fixed to the front part of the base material 41, and a plurality of tips 143.

[0035] The shape and configuration of the base material 41 and the bit 42 are similar to those of the first embodiment.

[0036] Each tip 143 is a substantially cylindrical member having an axis perpendicular to side surface portion 41D, in other words, an axis extending in the rotation direction. Each tip 143 is fixed by being press-fitted into side surface portion 41D.

[0037] The tip 143 is made of a hard alloy such as tungsten carbide and has a higher hardness than the base material 41. The tip 143 is preferably made of a material conforming to JIS: E5 or JIS: E4.

[0038] Moreover, it is preferable that the hardness of the bit 42 is higher than the hardness of the tip 143. With such a configuration, the wear resistance performance during excavation of the face E can be maintained by the bit 42 and the base material 41, and the impact resistance performance can be improved by the tip 143.

[0039] <Effects> In the above embodiment, the following aspects are shown.

[0040] (Mode 1) The cutter bit 4, 104, 204 comprises a base material 41 that can be attached to the cutter head 2 (corresponding to the rotating part), and a bit 42 that is attached to the base material 41, has an end portion facing the tunnel face E excavated by the tunnel boring machine 1, and has a hardness higher than that of the base material 41. The front end portion of the bit 42 extends in the rotation direction of the cutter head 2 and is formed in an arc shape that protrudes toward the tunnel face E.

[0041] The above configuration can improve the impact resistance of the bit 42 and the wear resistance of the base material 41. It can reduce the risk of the bit 42 falling off or breaking when passing through a gravel layer. Even if a layer different from the previous boring data is found, excavation can be continued without having to take measures such as temporarily halting construction and replacing the bit 42, so that process management and cost management can be ensured.

[0042] (Embodiment 2) In embodiment 1, the cutter bit 4, 104, 204 further includes a tip 43, 143 having a higher hardness than the base material 41. The base material 41 has a side portion 41D that extends intersecting the rotation direction of the cutter head 2 and to which the tip 43, 143 is attached.

[0043] In the above configuration, by attaching the tip 43, 143 harder than the base material 41, it is possible to efficiently perform excavation while reducing wear of the cutter bit 4, 104, 204. In detail, the side parts 41C, 41C of the base material 41, which are parts that face the ground during excavation, have low hardness and are therefore prone to wear. By attaching the tip 43, 143 harder than the base material 41 to the side parts 41D, 41D, 41E, it is possible to improve the wear resistance of the cutter bit 4, 104, 204. In addition, since the base material 41 compensates for the impact resistance of the tip 43, 143, the cutter bit 4, 104, 204 can maintain its impact resistance while improving its wear resistance.

[0044] (Embodiment 3) In embodiment 1 or 2, the tip 43, 143 is joined to the side portion 41D by thermal spraying.

[0045] In the above configuration, the tip 43 is firmly held to the side surface portion 41D by using a joining method by thermal spraying instead of brazing. The joining method by thermal spraying improves the impact resistance, which is a weak point of the brazed joining method. Therefore, the impact resistance of the cutter bit 4, 104, 204 itself is improved, and therefore the excavation performance can be improved.

[0046] (Embodiment 4) In any one of embodiments 1 to 3, tip 143 is made of diamond.

[0047] With the above configuration, the impact resistance of the cutter bit 104 can be improved.

[0048] (Embodiment 5) In any one of embodiments 1 to 4, tip 143 is press-fitted into side surface portion 41D.

[0049] In the above configuration, the tip 143 is firmly held to the side surface portion 41D by using press-fitting instead of brazing. The use of press-fitting improves the impact resistance, which is a weak point of brazing. Therefore, the cutter bit 104 can improve its own impact resistance and therefore improve its excavation performance.

[0050] (Embodiment 6) In any one of embodiments 1 to 5, tip 143 is made of a cemented carbide.

[0051] With the above configuration, the impact resistance of the cutter bit 204 can be improved.

[0052] (Embodiment 7) In any of embodiments 1 to 6, the hardness of the tip 43, 143 is lower than the hardness of the bit 42.

[0053] In the above configuration, the wear resistance of the cutter bits 104, 204 can be improved by attaching the tips 43, 143. In addition, since the bit 42 complements the impact resistance of the tips 43, 143, the cutter bits 104, 204 can maintain their impact resistance while improving their wear resistance. [Explanation of symbols]

[0054] 1. Tunnel boring machine 2 Cutter Head 3 Main body 4, 104, 204 cutter bits

Claims

1. A base material that can be attached to a rotating part of an excavator; a bit attached to the base material, the bit having an end facing a face excavated by the excavator, the bit having a hardness greater than that of the base material; The end portion extends in the rotation direction of the rotating portion and is formed in an arc shape protruding toward the face when viewed in the radial direction of the rotating portion. Cutabit.

2. Further comprising a tip having a hardness greater than that of the base material; The base material has a side surface portion extending in a direction intersecting with a rotation direction of the rotating part and to which the tip is attached. The cutter bit according to claim 1 .

3. The cutter bit according to claim 2 , wherein the tip is joined to the side portion by thermal spraying.

4. The cutter bit of claim 2 , wherein the tip is formed of diamond.

5. The cutter bit of claim 2 , wherein the tip is press-fit into the side portion.

6. The cutter bit of claim 2 , wherein the tip is made of a cemented carbide.

7. The cutter bit according to claim 2 , wherein the hardness of the tip is lower than the hardness of the bit.

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