JPH06100068B2 - Cutter head of shield excavator and disk cutter used for the cutter head - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a cutter head of a shield excavator suitable for crushing boulders and excavation with twisting, and a disk cutter used for the cutter head.

[Conventional technology]

A shield excavator having a dome-shaped cutter head equipped with a large number of front disk cutters is generally used as a shield excavator for excavating a boulder-mixed stratum.

(I) In order to dig up and crush gravel by arranging the disk cutter up to the outermost peripheral portion of the dome-shaped cutter head.

(Ii) In order to take gravel into the machine by providing an opening up to the outermost peripheral portion of the dome-shaped cutter head.

(Iii) To make it easier to take in the gravel above the face and push the gravel into the hole wall around the face.

6 and 7 show a conventional example of a shield excavator having a dome-shaped cutter head equipped with a disk cutter.

In the figure, reference numeral 1 is a shield excavator main body, which is provided with a dome-shaped cutter head 3 having a large number of disk cutters 2B mounted on the front portion thereof. It is supposed to be excavated. Behind the cutter head 3, there is provided a cutter head chamber 6 of a sealed structure which is partitioned from the inside of the main body 1 by a partition wall 1a and sealing mechanisms 8, 9 and 10, and gravel crushed by the disc cutter 2B is cut by the cutter head 3. Opening 3a provided on the front surface of 3
It is taken in from the cutter head chamber 6 to the rear of the main body 1 by the screw conveyor 7. There is also a shield excavator that discharges gravel by circulating muddy water (not shown) instead of the screw conveyor 7.

The disc cutter 2B is a rotary excavator in which single-row or double-row blades with a mountain-shaped cross section called a disc are provided. As shown in FIG. 6, the number of discs is two or three and the diameters of adjacent discs are equal. It is generally used that the blade tip is hardened with a cylinder type twin disc cutter or tri-disc cutter, the blade tip is embedded with a cemented carbide tip, or the blade tip is hardened with a single disc cutter having one disc. Another example of the disc cutter 2B mounted on the curved dome portion of the cutter head 3 is a truncated conical twin disc cutter or tri-disc cutter having two or three discs with different disc diameters. There are also cases where the blade edge is hardened or a cemented carbide tip is embedded in the blade edge.

Next, more detailed contents of these various cutters and a crushing mechanism of boulders will be described.

FIG. 8 shows a typical example of a conventionally used disc cutter. (A) is a hardened blade type cylinder type twin disc cutter, (b) is a hardened blade type frustoconical tri-disc. FIG. 3 is a view of a cutter, (c) is a cylinder type twin disc cutter with a cemented carbide tip embedded cutting edge type, and (d) is an external view of a frustoconical tri-disc cutter with a cemented carbide tip embedded cutting edge type. These disc cutters 2B are rotatably supported by a shaft 23 through a built-in bearing,
With the cutter head 3 fixed to a frame (not shown)
It is designed to be attached to.

The quenching blade tip type cutter has the advantage that the blade tip can be replaced as a separate item, and the blade tip angle is generally 90 ° to 105 ° due to the trade-off between excavability, blade life and strength, and the blade tip shape is symmetrical.

Carbide tip embedded cutting edge type cutters have superior wear resistance because the hardness of the carbide tips is higher than the hardened cutting edge type cutters, and the cutting edge angle is generally 90 ° to 105 ° (cutting edge angle 90
In some cases, the cutting edge shape is symmetrical. The cemented carbide tip 21 has a dome shape with a round tip and a chisel shape with a sharp tip, but a chisel shape with a tip embedded is suitable for crushing boulders.

The frusto-conical cutter is a disc cutter having a plurality of discs, in which the inner disc diameter of adjacent discs near the center of the cutter head is smaller than the outer disc diameter of the disc far from the center of the cutter head. That is, as shown in FIG. 9, the closer the apex of the cone 24, which is the outer shape of the cutter, to the cutter revolving shaft 25 at the center of the cutter head, the closer the inner and outer discs rotate when the cutter rolls. It can be said that the aim is to reduce the abrasion of the cutter blade edge and to crush the boulder without moving it from the current position, because the rotation deviation of the blade becomes smaller and the slip becomes smaller.

The main crushing mechanism of boulders by these disk cutters is
As shown in Figs. 10 (a) and 10 (b), the cutter blade edge is pressed against the boulder 31 by the excessive thrust of the shield excavator and rotated to form a V groove or a crack 32 in the boulder, and further between adjacent disks. Therefore, the wedge effect is applied to boulder 31 that is strong in the compression direction but weak in the shear direction to cause crushing 33 in the shear direction called adjacent crushing. However, in order to cause adjacent crushing of boulders by this main crushing mechanism, the surrounding rocks surrounding the boulders are buried or moved due to the pushing force by the thrust and the rolling force by the rotational force. It is necessary to have a strength enough to take a reaction force that does not cause a lump.

[Problems to be Solved by the Invention]

Conventionally used disk cutters have the following drawbacks.

(1) Disadvantages of a single disk cutter (hardened blade tip type) It is mainly used in a rock tunnel excavator whose cutter head chamber is not a closed type and has a large cutter head rotation speed. If this is applied to a shield excavator that has a closed cutter head chamber and discharges soil away from the screw conveyor, it will result in boulders due to the size of the disk cutter itself and the space constraints for securing an opening for the cutter head to collect debris. It is more difficult than other disc cutters to equip a large number of discs that cause adjacent crushing.

With a single-row blade, the blade tip does not always hit the center of the gravel, so the gravel moves each time the blade tip rolls,
Grooves and cracks are hard to form, and boulders cannot be crushed well.

Since it is a quenching type cutting edge with a hardness lower than that of a cemented carbide tip embedded type cutting edge, when used as a dome curved surface disk cutter with a long rolling distance (twice the rolling distance compared to the flat head disk cutter), The life of the cutting edge is short and it is necessary to replace the cutting edge ring during excavation.

When mounted on the curved surface of the dome, as shown in Fig. 11, the cutter axis inclines up to 70 ° from the vertical facet 19 which is perpendicular to the excavation direction, and the cutting edge faces in the direction perpendicular to the dome excavation surface 30. Therefore, even if it is possible to push small pebbles into the hole wall around the face, but for boulders that cannot be pushed into the hole wall, the direction of the cutting edge deviates greatly from the excavation direction,
The boulders are hit with a surface (and a surface that travels in the direction of excavation from the vertical facet 19) 26 rather than a line.

In the case of a boulder-mixed stratum that encloses boulders and has a high ground strength, since boulders do not move, sufficient thrust and rotational force can be transmitted. Boulders can be crushed using the wedge effect.

However, in general, there are many cases where the strength of the surrounding rocks that enclose boulders is weak in the boulder-mixed stratum, and in this case, because the boulders move, sufficient thrust and rotational force cannot be transmitted,
When hitting the surface 26, the biteability to the boulder is poor, and the wedge effect of the surface 26 does not work well on the dome excavation surface 30 and the boulder cannot be crushed well.

Also, if you try to increase the thrust to the extent that boulders do not move, the shield excavator's hundreds of tons of thrust are concentrated and applied to a specific disc cutter with the blade tip not fully penetrating, and the blade tip and the bearing with built-in cutter are attached. Will be damaged. Furthermore, if the boulders under the face cannot be crushed, the excavator may climb up to the boulders.

On the other hand, comparing the rotation speed of the cutter head outer circumference of the shield excavator equipped with a disk cutter and the rock tunnel excavator, the former is about 20 m / min which is about 1/5 of the latter tunnel excavator. Has become. This is because of a restriction on the strength against friction (heat) due to the rotation of the sealing mechanism of the closed cutter chamber.

In this way, the rotational speed of the disk cutter 2B on the outer peripheral portion of the cutter head of the shield excavator in FIG. 11 is about 1/5 that of a tunnel excavator, which is smaller than that of the tunnel excavator. It is necessary to increase the bite into the boulder per revolution, but if the thrust is increased with respect to the disc cutter with poor biteability, the shield excavator with the blade edge not fully penetrating as described above. The excessive thrust that it has concentrates on a specific disc cutter and adds,
The cutting edge and built-in bearing will be damaged. In addition, if the thrust is kept low to prevent damage to the cutting edge and built-in bearing, biting will deteriorate and a large number of passes (the number of times the cutting edge passes) will be required to crush boulders, while
Since the rotation speed is slow, the digging speed becomes small.

(2) Disadvantages of cylinder type twin disc cutter or try disc cutter (quenching edge type) Although the disadvantages of (1) and (1) are solved,
In addition to the same drawbacks as above, it has the following drawbacks.

Since the inner disk near the center of the cutter head and the outer disk far from the center of the cutter head have large rotational deviations between their own and revolution, the cutter slips and wears,
Every time it rolls, it cannot move well by moving boulders.

(3) The drawbacks of the truncated cone twin disc cutter or the tri-disc cutter (quenched blade edge type), the drawbacks of (1) and (2) are solved, but they have the same drawbacks of (1). .

(4) Disadvantages of frustoconical twin disc cutter or tri-disc cutter (carbide tip embedded cutting edge type) The disadvantages of (1) and (2) are solved, but the same as (1) It has drawbacks.

This is described in (1) because the cemented carbide tip 21 is embedded in a direction perpendicular to the conical surface of the frusto-conical shape and the tip edge shape is symmetrical as shown in FIG. In the same way as in the case of the dome, the edge of the curved surface of the dome deviates greatly from the direction of excavation and hits the boulder.

Further, it has the following drawbacks.

Although it depends on the hardness of the gravel, before the hard carbide tip 21 which is generally hard reaches the wear limit, the base material around the tip with a lower hardness
The carbide tip 21 tends to be worn out and the carbide tip 21 tends to fall off.

As described above, the conventional dome-shaped cutter head is used for the disk cutter mounted on the dome curved surface (1),
Even if any of the disc cutters (2), (3) and (4) is used, it has a big drawback that the boulder cannot be sufficiently crushed when the strength of the surrounding rock surrounding the boulder is weak. It was

An object of the present invention is to make the disk cutter mounted on the dome curved surface part have good biteability such that it bites into boulders with a small thrust even when the surrounding natural strength surrounding the boulders is weak. In addition to the wedge effect shown in the figure, by adding a new excavation effect that newly causes boulders to actively twist in the direction of excavation, a shield excavator capable of efficiently crushing boulders efficiently with the minimum necessary thrust. It is an object to provide a cutter head and a disk cutter used for the cutter head.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the invention according to claim 1 is a dome-shaped cutter head which is provided in a front part of a shield excavator main body and in which a large number of disk cutters embedded in a cemented carbide tip are mounted on a curved surface of a dome. A hard tip of a disk cutter to be mounted on a curved surface is a chisel-shaped tip having a cutting edge formed by a surface facing the excavation direction and a surface on the opposite side, and the tip facing the excavation direction is the tip end of the tip. It is characterized in that it is embedded in the cutter base metal at an angle that prevents business trips from a plane perpendicular to the direction of excavation including.

According to a fourth aspect of the present invention, there is provided a cemented carbide tip-embedded cutting edge type disc cutter, which is used by mounting a large number on a dome curved surface portion of a dome-shaped cutter head provided at a front portion of a shield excavator body. In the state of use, a chisel-shaped tip having a cutting edge formed by a surface facing the excavation direction and a surface opposite to the cemented carbide tip is used, and the surface facing the excavation direction includes the tip of the tip. It is characterized in that it is embedded in the cutter base material at an angle so that it will not travel on the right angle.

[Action]

By setting the embedding direction of the cemented carbide tip of the disk cutter attached to the dome curved surface and the shape of the tip of the tip as described above, the strength of the surrounding rock surrounding the boulder is weak and the boulder moves more than enough thrust. And the turning force cannot be transmitted to the boulder that cannot be pushed into the hole wall in the stratum, the tip edge of the tip hits the line more closely than the excavation direction, and not the surface, but bites with an extremely small thrust. Since it has good properties, it is possible to sufficiently crush boulders using the wedge effect, and actively twist the boulders in the excavation direction between the tip and the cutting edge that are newly oriented in the excavation direction. By also providing the excavation effect that occurs, it is possible to sufficiently crush the boulders in the boulder-mixed strata with weak ground strength with the minimum necessary thrust.

Further, in a boulder-mixed stratum such that the surrounding ground strength can be obtained to some extent, by applying the same thrust as that of the conventional disc cutter, the disc cutter according to the present invention has a good biting property, and thus a small number of passes ( The boulder can be crushed depending on the number of times the blade edge passes), and a large excavation speed can be obtained even in a shield excavator having a low rotation speed.

〔Example〕

FIG. 1 shows a disk cutter to be mounted on the dome curved surface of the cutter head of a shield excavator which discharges gravel by a screw conveyor or circulation of muddy water, according to the present invention. The following is an example. The basic configuration of the frustoconical tri-disc cutter of this embodiment is the same as that conventionally used, and FIG. 1 shows only the blade portion of the disc cutter 2A in which the carbide tip 21 is embedded in cross section. It is a thing.

In FIG. 1, 18 is a ground to be excavated, 19 is a vertical facet which includes the tip of a carbide tip 21 and is perpendicular to the direction of excavation, 30 is formed by a cutter head 3 and a disk cutter 2A of a dome curved surface portion. It is a dome excavation surface.

As the cemented carbide tip 21 to be embedded in the disc cutter 2A, a chisel-shaped tip (see FIG. 3) having a cutting edge formed by a surface 21a facing the excavation direction and a surface 21b on the opposite side thereof is used. Carbide tip 21 so that the wedge effect of the tip edge works in the direction of excavation and improves the biteability of the tip edge.
Point the cutting edge of to the direction of digging. That is, the rake angle α (α ≧ 0 degree, in this embodiment α = 0 degree) is set on the surface 21a of the chip facing the excavation direction so as not to travel beyond the vertical facet 19.
In addition, on the surface 21b on the opposite side of the tip, the clearance angle β (β
> 5 degrees, β = 30 degrees in this embodiment). The larger β becomes, the weaker the contact with the surface 21b becomes, and the smaller the excavation resistance becomes. Further, an angle θ ₁ formed by the surface 21a facing the chip embedding direction and the chip excavation direction and an angle θ ₂ formed by the chip embedding direction and the surface 21b on the opposite side of the chip are θ ₂
> Θ ₁ (θ in the present embodiment of the outermost peripheral cutter on the dome curved surface portion)
₁ = 30 degrees, θ ₂ = 60 degrees).

When the tip edge shape of the carbide tip 21 is set as above,
Compared to the conventional cemented carbide tip-embedded cutting edge type disc cutter shown in Fig. 12, the tip edge comes into contact with boulders at an angle closer to the excavation direction and with a line rather than a surface, so it bites with an extremely small thrust. It is clear that such biteability is good. In addition, since a new digging effect that positively twists in the digging direction between the tip and the cutting edge of the boulder facing the digging direction in the digging direction can be given, the surrounding ground strength is weak. The boulders in the formation can be efficiently and sufficiently crushed with the minimum required thrust.

Further, by making the tip edge shape asymmetrical as described above, it is possible to increase the clearance 27 of the valley portion between the disk cutter blade edges while ensuring a sufficient thickness of the base material holding the carbide tip 21. It is possible to prevent the chips from falling off due to the wear of the base material, which has a great influence on the service life of the cutting edge type disk cutter with a super hard chip embedded therein, and is also effective in that the excavation surface does not hinder the excavation. That is, if Fig. 13 (a)
, Θ ₁ = θ ₂ (in the illustrated example, θ ₁ = θ ₂ = 45
), A rake angle α (α ≧ 0 °, α = 0 ° in the illustrated example) so that the face 21a facing the excavation direction of the chip does not travel beyond the vertical facet 19. 0
The clearance angle β with respect to the dome excavation surface 30 is given to the surface 21b on the opposite side of the tip to prevent excavation resistance.
If (β> 5 degrees, β = 30 degrees in the illustrated example) is given, it becomes necessary to thicken the base material on the back surface side of the chip in order to hold the chip. On the other hand, when crushed pieces such as gravel are generated during excavation of the disc cutter, the excavation surface is formed so as to rise in the valley between the cutting edges of the disc cutter, so if the clearance 27 in the valley of the disc cutter is small, crush There is a risk that the excavation surface and the valley of the disc cutter will fall before the fragments are generated, which will hinder the excavation. Further, if the same clearance 27 as in the case of using the asymmetrical tip shown in FIG. 13 (b) is taken by using this symmetric tip of θ ₁ = θ ₂ , the base material holding the tip is Since the thickness becomes thin, chipping off becomes a problem. Therefore, as shown in FIG. 13 (b), by using the above-mentioned asymmetric tip, the clearance 27 between the disc cutter blade edges can be eliminated while ensuring a sufficient thickness of the base material holding the cemented carbide tip 21. Can be large.

In the present embodiment, as a measure against wear of the base material, surface hard facing 22 having a hardness higher than that of the base material is applied to the surfaces of the same disk between the chips and the side surface of the disk for reinforcement. FIG. 2 is a view showing the surface-hardened overlay 22 in the arrow A view of FIG. 1 with diagonal lines.

FIG. 4 is a cross-sectional view of a dome curved surface portion of a cutter head equipped with a disk cutter according to the present invention. The disk cutter on the dome curved surface portion is a dry disk cutter having three disks, and the cutter head among adjacent disks. The disc cutter 2A has a frustoconical cutter in which the inner disc diameter near the center of the is smaller than the outer disc diameter, and the embedding direction of the cemented carbide tip embedded in the cutter and the tip edge shape are as shown in Fig. 1. This is an example in which a large number (three of which are shown in the figure) are mounted on the curved dome portion of the head 3 and the dome excavation surface 30 is formed by these disk cutters.

FIG. 5 is a front view showing an example of a dome-shaped cutter head equipped with a disc cutter according to the present invention, which is a cutter head 3
The disk cutter to be attached to the dome curved surface that is the outer peripheral part of the disk is a frusto-conical tri-disk cutter. The embedding direction of the cemented carbide tip and the tip shape of the tip are as shown in Fig. 1. The disk cutter to be mounted on the flat head inside the dome curved surface is the same quenching blade type as the one used in the past and is a cylinder type disk cutter with the same diameter of adjacent disks (or cemented carbide in the direction perpendicular to the cutter axis). This is a cemented carbide tip-embedded tip type cylindrical disk cutter) 2B in which the tip is embedded and the tip edge shape is symmetrical.

In FIG. 5, 3a is an opening for taking in the gravel of the cutter head 3, 3b is a cutter bit attached to the cutter head 3, and 3c is a surface hard facing portion (shown with diagonal lines) on the front surface of the cutter head. is there.

FIG. 14 shows an example of the gauge cutter. The gauge cutter of this embodiment provides the outermost blade edge of the gauge cutter with a clearance angle γ (γ ≧ 0, γ = 10 degrees in this embodiment) with respect to the tunnel inner peripheral surface 40 on the back side 21b of the blade tip, and ,
The cutting edge according to the present invention is adopted as the cutting edge on the inner peripheral side. That is, in the gauge cutter, the back surface side of the outermost blade edge faces the inner peripheral surface of the excavated circular section tunnel, not the dome-shaped excavation surface like the inner peripheral blade edge. Here, there is no cutting edge on the outer peripheral side of the outermost cutting edge of the gauge cutter that crushes adjacent gravel on the back side of the outermost cutting edge. If the cutting edge of the outermost periphery is protruding outward from the excavation direction, and if the ground is such that strong gravel is expected to appear, there is no choice but to crush the gravel on the back side of the cutting edge, There is a risk of resistance to digging. In such a case, regarding the outermost cutting edge of the gauge cutter, the tunnel on the rear side of the outermost cutting edge of the gauge cutter should be set so that the rear side of the cutting edge does not resist the excavation direction with respect to the inner peripheral surface of the tunnel. It may be better to give a clearance angle γ (γ ≧ 0) to the inner peripheral surface.

Note that the term dome curved surface portion in this specification is named to distinguish it from the flat head portion of the dome-shaped cutter head (a flat surface portion perpendicular to the direction of excavation), and is formed on a normal curved surface around the flat head portion. However, even if the portion on which the disc cutter is mounted is locally formed in a flat surface, it does not leave a substantially homogeneous region.

〔The invention's effect〕

 According to the present invention, the following effects can be obtained.

(1) A chisel-shaped tip having a cutting edge formed by a surface of a hard disk tip of a disk cutter to be mounted on the curved surface of the dome of the cutter head and a surface on the opposite side,
By embedding the chip in the disc cutter at an angle such that the surface facing the direction of excavation does not travel than the surface at right angles to the direction of excavation including the tip of the chip, the strength of the surrounding rock surrounding the boulder is increased. Since the boulders are weak and the thrust and rotational force cannot be transmitted because the boulders move, the tip blade edge will hit the boulders that cannot be pushed into the hole wall in the stratum in the formation at an angle closer to the excavation direction. The effect can be fully exerted and the penetration resistance is small. That is, since the cutting edge hits against the boulder with a line rather than a surface, it has extremely good biteability, and has a great effect that the boulder can be crushed well by utilizing the wedge effect, and a new boulder is scooped in the direction of excavation. Since an excavation effect of positively twisting and raising in the excavation direction is also provided between the tip edge and the edge pointed at an angle, boulders can be efficiently and sufficiently crushed with the minimum necessary thrust.
Therefore, the excessive thrust of the excavator is concentrated in a state where the blade edge does not penetrate, and it is possible to prevent the blade edge of the cutter and the built-in bearing from being damaged, and the excavator may also climb up to crushed boulders. Disappear. Further, the tip edge shape is an asymmetrical shape such that the angle θ ₁ formed by the surface facing the excavation direction with respect to the chip embedding direction and the angle θ ₂ formed by the opposite surface are θ ₂ > θ _1. By doing so, it is possible to improve the biteability and to secure a sufficient thickness of the base material that holds the chips, which is also effective in preventing the chips from falling off due to wear of the base material.

(2) Since the blade tip has a cemented carbide tip with a hardness higher than that of the quenching blade tip, the disk cutter on the dome curved surface with a long rolling distance can have a long life, and it is necessary to replace the blade tip during propulsion like the quenching blade tip. There is no.

(3) By using a twin disk cutter or a tri-disk cutter as the disk cutter to be mounted on the curved surface of the dome of the cutter head, it is possible to cause adjacent crushing of boulders while ensuring a sufficient opening for gravel intake. Since it can be done, and the boulder is hard to move because it is hit by two or three blades, V grooves and cracks are easily formed, and the crushing effect is great. In particular, when the cutter blade edge of the dome curved surface portion hits the boulder at an angle close to the propelling direction as in the present invention, it is effective because the boulder becomes more difficult to move due to the biting of the blade edge.

(4) By using a frusto-conical cutter as the disk cutter on the dome curved surface, the inner disk and the outer disk in the radial direction of the cutter head have a smaller rotational deviation between their own rotation and revolution, which reduces the slippage of the cutter and reduces wear. Hard to do.
Further, when the cutter has a small slip, the action of moving the boulder from the current position becomes small, and the boulder can be crushed adjacently. In particular, when the cutter blade edge of the dome curved surface portion hits the boulder at an angle close to the propulsion direction as in the present invention, the penetration resistance is small, the blade edge is less worn, and the boulder becomes harder to move due to the bite of the blade edge. , The crushing effect is even greater.

(5) Base metal around the tip before the tip reaches the wear limit by applying hard facing to the surface of the same disc of the cutter with the cemented carbide tip embedded between the tips and the side of the disc to reinforce the surface. It is possible to prevent the chips from being worn and the chips coming off. Further, as a measure against the wear of the base material, it is possible to embed another cemented carbide tip on the surface between the tips and the side surface of the disk, but it is more economical than that.

[Brief description of drawings]

1 to 5 are views showing an embodiment of the present invention, and FIG. 1 is a sectional view of a main part of a disk cutter mounted on a curved surface of a dome,
FIG. 2 is a view taken in the direction of arrow A in FIG. 1, FIG. 3 is a perspective view of a cemented carbide tip embedded in a disc cutter, FIG. 4 is a cross-sectional view of a curved surface of a dome on which the disc cutter is mounted, and FIG. 5 is a disc cutter. Fig. 6 is a front view of a cutter head equipped with a blade, Fig. 6 is a cross-sectional view showing a conventional example of a shield excavator for crushing boulders, Fig. 7 is a front view of the cutter head, and Fig. 8 is a typical disk cutter used in the past. An external view showing an example, FIG. 9 is an explanatory view of a frustoconical cutter, FIG. 10 is an explanatory view of a boulder crushing mechanism, and FIG.
FIG. 12 and FIG. 12 are cross-sectional views of a main part showing an excavated state of a conventional disk cutter, FIG. 13 is a cross-sectional view for explaining a comparison between a symmetrical tip and an asymmetrical tip, and FIG. It is sectional drawing of an Example. 1 ... shield excavator main body, 2A ... disk cutter according to the present invention, 2B ... conventionally used disk cutter, 3
...... Dome-like cutter head, 19 ...... Vertical face, 20 ......
Cutter base material, 21 …… Carbide chip, 21a …… Surface of the chip facing the excavation direction, 21b …… Surface opposite to the chip, 22 ……
Hard facing surface, 27 …… Escape of valley between disc cutter edges, 30 …… Dome excavation surface, 40 …… Inner surface of tunnel.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Yoshida 650 Jinrachicho, Tsuchiura City, Ibaraki Prefecture Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd. Ceremony Company Tsuchiura Plant (72) Inventor Nobuyoshi Tamachi 2-544 Shimoyama-cho, Furukawa City, Ibaraki Prefecture (72) Inventor Shigeru Kumakura 879-2 Inamiya, Sowa-cho, Sarushima-gun, Ibaraki Prefecture (72) Inventor Satoshi Suzuki Tokyo 3-23-14 Takanawa, Minato-ku, Japan Communications Construction Co., Ltd. (72) Inventor Takeo Iida 3-23-14, Takanawa, Minato-ku, Tokyo, Japan Communications Construction Co., Ltd. (56) Reference JP-A-64-6498 (JP, A) JP-A-54-154135 (JP, A) JP-A-63-122896 (JP, A)

Claims (7)

[Claims] 1. A dome-shaped cutter head provided in the front part of a shield excavator main body, wherein a large number of disk cutters having cemented carbide tips embedded in the dome curved surface portion are mounted. The tip is a chisel-shaped tip having a cutting edge formed by a surface facing the excavation direction and a surface on the opposite side, and the surface of the tip facing the excavation direction travels from a surface perpendicular to the excavation direction including the tip of the chip. A cutter head for a shield excavator, which is characterized in that it is embedded in the cutter base material at an angle that does not prevent it. Wherein a cutting edge shape of the hard tip, the angle of the surface facing the excavation direction the chip embedded direction theta ₁
The cutter head for a shield excavator according to claim 1, wherein the angle θ ₂ formed by the opposite surface and the opposite surface is asymmetrical such that θ ₁ > θ ₂ . 3. A disc cutter to be mounted on the curved surface of the dome is a twin disc cutter or a tri-disc cutter having two or three discs, and the disc that is closer to the center of the cutter head among adjacent discs. 3. A shield excavator according to claim 1 or 2, wherein a frusto-conical cutter having a diameter smaller than that of a disk farther from the center of the cutter head is provided, and each disk is equipped with a disk cutter having the cemented carbide tip embedded therein. Cutter head. 4. A cemented carbide tip-embedded cutting edge type disc cutter, which is used by mounting a large number on a dome curved surface portion of a dome-shaped cutter head provided in the front part of a shield excavator main body, wherein the cemented carbide tip of the disc cutter is A chisel-shaped tip having a cutting edge formed by a surface facing the excavation direction in use and a surface opposite to the excavation direction, and the surface facing the excavation direction of the tip is a plane perpendicular to the excavation direction including the tip of the tip. A disc cutter for a cutter head of a shield excavator, which is embedded in the cutter base material at an angle so as not to travel. 5. An angle θ formed by the surface of the cutting edge of the cemented carbide tip with respect to the chip embedding direction facing the excavation direction.
5. The disk cutter for a cutter head of a shield excavator according to claim 4, wherein the angle θ ₂ formed by ₁ and the opposite surface is asymmetrical such that θ ₂ > θ ₁ . 6. The number of disks is 2 for the disk cutter.
3 or 3 twin disc cutters or tri-disc cutters, and a frusto-conical shape in which the diameter of the disc adjacent to the center of the cutter head is smaller than the diameter of the disc far from the center of the cutter head 6. A disk cutter for a cutter head of a shield excavator according to claim 4, wherein the cutter is a cutter, and each of the disks is embedded with the carbide tip. 7. The shield according to any one of claims 4 to 6, wherein a surface between the cemented carbide chips embedded in the same disc of the disc cutter and a side face of the disc are hardened by hardfacing. Disk cutter for cutter head of excavator.