Cutter bit

Abstract

To provide a cutter bit capable of reducing the number of cutter bits mounted on a cutter head.SOLUTION: A cutter bit 1 according to one embodiment includes a base material 2 and a plurality of tips 3 held by the base material 2 while being aligned in a specific direction. The tips 3 include a scraping tip 31 exposed in a first direction, which is one of the specific directions, and a cutting tip 34 exposed in a second direction, which is the other of the specific directions. The scraping tip 31 has a rake face 31a that is inclined in the first direction toward a third direction, which is a direction in which the base material 2 holds the tips 3. The cutting tip 34 has a shape that is pointed toward at least one of the second direction and the third direction.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cutter bit mounted on a cutter head of a tunnel boring machine. [Background technology]

[0002] In tunnel boring machines such as shield machines, the cutter head that excavates the natural ground is rotatably supported on the excavator body, and cutter bits such as a leading bit and teeth bit are mounted on the cutter head. The leading bit plays the role of loosening the soil by making cuts in the tunnel face, and the teeth bit plays the role of efficiently taking the excavated soil into the chamber between the cutter head and the excavator body.

[0003] For example, Patent Document 1 describes a teeth bit. This teeth bit includes a top surface facing the travel direction of the tunnel boring machine (i.e., the front side of the cutter head), a bottom surface facing the opposite side to the travel direction of the tunnel boring machine (i.e., the rear side of the cutter head), a front surface facing the rotation direction of the cutter head, a rear surface facing the opposite side to the rotation direction of the cutter head, and a pair of side surfaces. The top surface of the teeth bit is inclined from the rear surface to the front surface so as to move away from the bottom surface. The front surface is also inclined from the bottom surface to the top surface so as to move away from the back surface (so-called scooping surface). For this reason, the angle between the front surface and the top surface is an acute angle. The acute angle part of the teeth bit is composed of a chip, and the rest is composed of a base material. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-166216 A Summary of the Invention [Problem to be solved by the invention]

[0005] Teeth bits are designed to rotate in one direction. Therefore, when the cutter head rotates in both directions, a set of teeth bits is arranged in the same position, but in opposite directions, in order to scrape off the excavated soil in each direction of rotation and to protect the back of the teeth bits. If a leading bit is also arranged in addition to such a set of teeth bits, the number of cutter bits to be mounted will increase.

[0006] Therefore, an object of the present invention is to provide a cutter bit that can reduce the number of cutter bits that can be mounted on a cutter head. [Means for solving the problem]

[0007] The present invention provides a cutter bit mounted on a cutter head of a tunnel boring machine, comprising a base material and a plurality of chips held on the base material in a state lined up in a specific direction, the plurality of chips including a scraping chip exposed in a first direction which is one of the specific directions and a cutting chip exposed in a second direction which is the other of the specific directions, the scraping chip having a scraping surface that is inclined in the first direction toward a third direction which is the direction in which the base material holds the plurality of chips, and the cutting chip has a shape that is pointed toward at least one of the second direction and the third direction. Effect of the Invention

[0008] According to the present invention, a cutter bit is provided that can reduce the number of cutter bits to be mounted on a cutter head. [Brief description of the drawings]

[0009] [Figure 1] 1(a) and 1(b) are perspective views of a cutter bit according to an embodiment of the present invention, viewed from different directions. [Diagram 2] 2(a) and (b) are a plan view and a side view, respectively, of the cutter bit. [Diagram 3]FIG. 2 is a front view of a portion of a cutter head on which the cutter bit is mounted. [Figure 4] FIG. 13 is a side view of a cutter bit according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] 1(a) and (b) show a cutter bit 1 according to one embodiment of the present invention. This cutter bit 1 is mounted on a cutter head 5 (see FIG. 3) of a tunnel boring machine.

[0011] The cutter bit 1 includes a base material 2 and a plurality of tips 3 held by the base material 2 while being aligned in a specific direction. In this embodiment, the number of tips 3 is four, but the number of tips 3 may be two or three, or may be five or more.

[0012] For ease of explanation, the specific direction in which the chips 3 are lined up will be referred to as the front-rear direction, the direction in which the base material 2 holds the chips 3, i.e., the direction perpendicular to the specific direction, in which the base material 2 and the chips 3 are lined up, will be referred to as the chip 3 side up and the opposite side down, and the direction perpendicular to the front-rear direction and the up-down direction will be referred to as the width direction or left-right direction. In other words, the front, which is one of the specific directions, corresponds to the first direction of the present invention, the rear, which is the other of the specific directions, corresponds to the second direction of the present invention, and the up corresponds to the third direction of the present invention.

[0013] The base material 2 includes a base 22 located below all of the tips 3, a plurality of protrusions 23-25 ​​protruding upward from the base 22, and an attachment portion 21 protruding downward from the base 22. The attachment portion 21 is provided with a plurality of countersunk holes 21a for fixing bolts that fix the cutter bit 1 to the cutter head 5.

[0014] The protrusions 23 to 25 are aligned in the front-rear direction, and an insertion groove for the tip 3 is formed between adjacent protrusions (between the protrusions 23 and 24, and between the protrusions 24 and 25). In addition, the frontmost protrusion 23 and the base 22 form a notch into which the frontmost tip 3 fits, and the rearmost protrusion 25 and the base 22 form a notch into which the rearmost tip 3 fits. Each tip 3 is joined to the base material 2 by adhesive or brazing.

[0015] The tip 3 includes a scraping tip 31 located at the front end, a cutting tip 34 located at the rear end, and intermediate tips 32, 33 located therebetween. The scraping tip 31 is exposed at the front, and the cutting tip 34 is exposed at the rear.

[0016] A build-up layer 4 is formed on the base 22 and the protrusions 23 to 25 of the base material 2. The build-up layer 4 covers the base 22 from the periphery in the front-rear and left-right directions, and covers the protrusions 23 to 25 from the left-right directions and above. Note that the build-up layer 4 is omitted from illustration in Figures 1(a) and (b).

[0017] The tip 3 and the buildup layer 4 have a higher hardness than the base material 2. For example, the base material 2 is made of a material such as carbon steel, alloy steel, or tool steel, the tip 3 is made of a material such as a sintered alloy such as tungsten carbide, and the buildup layer 4 is made of a material such as a martensitic alloy.

[0018] In this embodiment, all the chips 3 and the protrusions 23 to 25 have the same contour in the upward and left-right directions. That is, the upper end faces of all the chips 3 and the upper end faces of the protrusions 23 to 25 are located on the same plane. However, all the chips 3 may protrude upward and left-right from the protrusions 23 to 25.

[0019] In this embodiment, all the chips 3 and protrusions 23 to 25 have a shape that is pointed upward. In other words, all the chips 3 and protrusions 23 to 25 have a shape in which the corners between the upper and left sides and the corners between the upper and right sides are obliquely cut out.

[0020] In this embodiment, the tips 3 other than the intermediate tip 32 located at the front among the tips 3, i.e., the scraping tip 31, the intermediate tip 33 and the cutting tip 34, have approximately the same height in the vertical direction. On the other hand, the height of the intermediate tip 32 is approximately 1 / 3 of the height of the scraping tip 31, the intermediate tip 33 and the cutting tip 34. Therefore, the lower parts of the convex parts 23, 24 of the base material 2 are integrated between the scraping tip 31 and the intermediate tip 33.

[0021] The scraping tip 31 has a rake face 31a that is inclined upward and forward. The rake angle of the rake face 31a with respect to the vertical direction is, for example, 5 to 25 degrees, and preferably 15 to 20 degrees. In this embodiment, the scraping tip 31 is a plate of a constant thickness, and the scraping tip 31 itself is inclined at the same angle as the rake face 31a. However, the scraping tip 31 may have a substantially trapezoidal cross section that is thicker toward the top.

[0022] In this embodiment, the rearward-facing surface of the cutting tip 34 is inclined forward from the center toward both sides in the width direction. In other words, the cutting tip 34 has a shape that is pointed not only upward but also toward the rear.

[0023] In the cutter bit 1 described above, when the cutter head 5 on which the cutter bit 1 is mounted so that the front-rear direction is along the rotation direction rotates forward, the scraping tip 31 can scrape off the earth and sand, and when the cutter head 5 rotates backward, the cutting tip 34 can make a cut into the face. Therefore, one cutter bit 1 can play the role of both the conventional teeth bit and the leading bit, and the number of bits mounted on the cutter head 5 can be reduced. In addition, it is not necessary to arrange a pair of teeth bits in the same position and opposite each other to protect the back of the teeth bit, as in the conventional teeth bits. As a result, the arrangement of the cutter bit 1 can be optimized in a limited space, and it is expected to improve excavation performance and prevent troubles.

[0024] For example, Fig. 3 shows a state in which an opening 52 is provided in a frame 51 of a cutter head 5, and three cutter bits 1 are mounted on the cutter head 5 around the opening 52. The cutter head 5 rotates in both directions A and B in Fig. 3.

[0025] In FIG. 3, three cutter bits 1 are arranged in a staggered pattern in the radial direction of the cutter head 5 (left-right direction in FIG. 3). In FIG. 3, the upper cutter bit 1 has the mounting portion 21 of the base material 2 fixed to the inner surface of the opening 52 so that the cutting tip 34 faces the A direction. Therefore, the rake surface 31a of the scraping tip 31 covers part of the opening 52 from above. Similarly, in FIG. 3, the lower two cutter bits 1 have the mounting portion 21 of the base material 2 fixed to the inner surface of the opening 52 so that the cutting tip 34 faces the B direction. Therefore, the rake surface 31a of the scraping tip 31 covers part of the opening 52 from above.

[0026] In Fig. 3, when the cutter head 5 rotates in the direction A, a cut is made in the face by the cutting tip 34 of the upper cutter bit 1, and soil is scraped off by the scraping tip 31 of the lower cutter bit 1 and taken into the opening 52. Similarly, in Fig. 3, when the cutter head 5 rotates in the direction B, a cut is made in the face by the cutting tip 34 of the lower cutter bit 1, and soil is scraped off by the scraping tip 31 of the upper cutter bit 1 and taken into the opening 52.

[0027] <Modification> The present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0028] For example, the base material 2 may not include the mounting portion 21, and the base 22 may be joined to the cutter head 5 by welding.

[0029] The cutting tip 34 does not necessarily have to be sharp toward both the front and rear, and may be sharp toward only one side. For example, when the cutting tip 34 is sharp toward the rear, the left and right sides of the cutting tip 34 may intersect with the upper side at right angles.

[0030] Furthermore, when the cutting tip 34 is pointed toward the rear, the rear-facing surface of the cutting tip 34 does not necessarily need to be inclined forward from the center toward both sides in the width direction, but may be inclined forward from the left side toward the right side, or may be inclined forward from the right side toward the left side. However, if the rear-facing surface of the cutting tip 34 is inclined forward from the center toward both sides in the width direction as in the above embodiment, it is expected that the resistance to sediment during cutting can be reduced and sediment flow can be made smoother.

[0031] Moreover, the scraping tip 31 does not necessarily need to be pointed upward, and the left and right sides of the scraping tip 31 may intersect with the upper side at right angles.

[0032] However, if all the tips 3 are pointed upward as in the above embodiment, good cutting can be achieved by the cutting tip 34, and the contours of all the tips 3 can be aligned at the top to prevent the scraping tip 31 and the cutting tip 34 from peeling off.

[0033] In addition, as in a modified cutter bit 1A shown in Figure 4, the scraping tip 31 may be embedded in the base material 2 at an angle larger than the angle of the scraping surface 31a, and the base material 2 may have a large scraping surface that is continuous with the scraping surface 31a of the scraping tip 31.

[0034] <Summary> In a first aspect, the present disclosure provides a cutter bit mounted on a cutter head of a tunnel boring machine, comprising a base material and a plurality of chips held on the base material in a state aligned in a specific direction, the plurality of chips including a scraping chip exposed in a first direction which is one of the specific directions and a cutting chip exposed in a second direction which is the other of the specific directions, the scraping chip having a scraping face inclined in the first direction toward a third direction which is the direction in which the base material holds the plurality of chips, and the cutting chip having a shape pointed toward at least one of the second direction and the third direction.

[0035] According to the above configuration, when the cutter head on which the cutter bit is mounted so that its specific direction is aligned with the direction of rotation rotates in a first direction, the scraping tip can scrape off the earth and sand, and when the cutter head rotates in a second direction, the cutting tip can make a cut into the face. Therefore, one cutter bit can serve the functions of both the conventional teeth bit and the leading bit, and the number of bits mounted on the cutter head can be reduced. In addition, there is no need to arrange a pair of teeth bits in the same position, opposite each other, to protect the back of the teeth bit, as in the conventional teeth bits.

[0036] As a second aspect, in the first aspect, the plurality of tips may have a shape that is pointed toward the third direction. With this configuration, the cutting tip can make a good incision, and the contours of all the tips can be aligned in the third direction to prevent the scraping tip and the incision tip from peeling off.

[0037] As a third aspect, in the first or second aspect, the surface of the cutting tip facing the second direction may be inclined in the first direction from the center toward both sides in the width direction perpendicular to the third direction. This configuration is expected to reduce the resistance to soil during cutting and to facilitate the flow of soil. [Explanation of symbols]

[0038] 1,1A Cutter Bit 2 Base material 3. Chip 31 Scraping Tip 31a Scooping face 34 Cutting tip 5 Cutter Head

Claims

1. A cutter bit mounted on a cutter head of a tunnel boring machine, A base material; A plurality of chips are held on the base material in a state aligned in a specific direction, The plurality of tips include a scraping tip exposed in a first direction which is one of the specific directions, and a cutting tip exposed in a second direction which is the other of the specific directions, The scraping tip has a scraping surface that is inclined in the first direction toward a third direction in which the base material holds the plurality of tips, The cutting tip has a shape that is pointed toward at least one of the second direction and the third direction.

2. The cutter bit according to claim 1 , wherein the plurality of tips have a shape that is pointed in the third direction.

3. The cutter bit according to claim 1 or 2, wherein a surface of the cutting tip facing the second direction is inclined in the first direction from a center toward both sides in a width direction perpendicular to the third direction.

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