JP2948674B2 - Cutter bits for earth and sand drilling - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutter bit which is attached to a cutter head of a shield machine and used for excavating earth and sand.

[0002]

2. Description of the Related Art Among various cutter bits used in a shield machine, FIG. 6 shows an example of a tooth bit 2 attached to a spoke of a cutter head 1 (see FIG. 12), and FIG. FIG. 12 shows an example of a fish tail bit 3 attached to the front center of FIG. 12, and FIG. 8 shows an example of a roller bit 4 attached to a dome-shaped cutter head (not shown) for excavating a gravelly formation. As seen in these examples, conventionally, a cutter bit is used in which a cemented carbide tip 5 and a base material 6 are bonded with silver solder or a cemented carbide tip 5 is pressed into the base material 6 and joined. It had been.

[0003]

As shown in FIGS. 9 to 11, when the conventional cutter bit is worn, as shown in FIGS. 9 to 11, the base material 6 having lower wear resistance than the carbide tip 5 wears first. The periphery of the cemented carbide tip 5 is now cut off. And, before the carbide tip 5 is completely worn, the carbide tip 5 peels off due to the impact or digging resistance received from the excavated earth and sand,
Cutter bits lose drilling capacity. Therefore, it is often impossible to adapt to difficult construction such as long-distance excavation and gravel layer excavation. It took time and money.

[0004] In the case of brazing a carbide tip,
When welding the cutter bit to the cutter head, the silver solder was melted by the welding heat and the chip was sometimes peeled off. An object of the present invention is to solve the above problems and provide a cutter bit that has a long service life, can be applied to difficult construction such as long-distance excavation and gravel layer excavation, and is not affected by welding heat.

[0005]

In order to achieve the above object, the present invention uses a functionally graded material in which a cemented carbide and a base material are continuously changed and fused to a cutter bit. Things.

[0006]

[Function] Functionally Graded Material (Functional Gra
The term “dient material (FGM)” is a general term for a material obtained by fusing materials having different properties by continuously changing their compositions. At the same time, super heat-resistant materials are considered (M & E,
April 1990, p. 46-47).

In the present invention, the concept of the functionally graded material is applied to a cutter bit. As shown in FIG. 5, the functionally graded material used in the cutter bit of the present invention shares the characteristics of both materials in the graded composition portion of the cemented carbide and the base material, and has a higher wear resistance than the base material alone. Is improved, so that the wear of the base material as seen in the conventional cutter bit is eliminated, and the super hard material does not peel off because it is fused with the base material.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows an example applied to a tooth bit 2, FIG. 2 shows an example applied to a fish tail bit 3, and FIG. FIG. 4 shows the wear mode of the cutter bit according to the present invention as a representative example of a tooth bit.

Each of the cutter bits shown in FIGS. 1 to 3 is made of a functionally graded material 7. This functionally graded material 7
The wear resistance of the super hard material (indicated by a black point) 8 and the base material (indicated by a white background) 9 is emphasized. The composition is continuously changed and fused so that the cemented carbide 8 is mainly used from the bit tip to the rake face and the back side, and the base material 9 is mainly used at the bit root where toughness is important. It is a thing. Among them, the cemented carbide 8 is made of carbide of a high melting point metal (WC. TiC or the like) which is a main material of the cemented carbide chip, and the base metal 9 is made of carbon steel, alloy steel or the like as a steel material for machine structure. Can be used.

As described in the above-mentioned reference, as a method for synthesizing a functionally gradient material, raw material powders are laminated with an arbitrary composition gradient, and a chemical reaction is caused to occur under pressure to synthesize.
Self-heating reaction method (SHS method) that performs molding and sintering at once,
A centrifugal force method for obtaining a gradient composition by utilizing a difference in specific gravity between molten metal and high melting point particles is known. In practicing the present invention, a functionally graded material obtained by fusing a cemented carbide and a base material with an arbitrary gradient composition by these existing techniques or other methods is shown in FIGS. Such various cutter bits are formed.

[0012]

The cutter bit of the present invention is made of a functionally graded material having characteristics of both a cemented carbide and a base material. Since there is no difference in abrasion resistance, as shown in FIG. 4, a substantially uniform form of wear is obtained, and the base material does not wear out before the carbide tip and the carbide tip does not peel off. Therefore, by increasing the amount of cemented carbide, the wear resistance of the entire cutter bit is improved by that much, the service life of the cutter bit can be extended, and the cemented carbide and the base material are fused. The cemented carbide tip does not come off due to the impact from the ground due to excavation of the gravel layer, etc. You can save money.

Further, according to the present invention, when welding a cutter bit to a cutter head as in the prior art, it is possible to solve the problem that silver solder is melted by welding heat and a carbide tip is peeled off.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a teeth bit as an example of a cutter bit to which the present invention is applied.

FIGS. 2A and 2B are views showing a fishtail bit as another example of the cutter bit to which the present invention is applied, wherein FIG. 2A is a partially cutaway side view, and FIG.

3A and 3B are views showing a roller bit as another example of a cutter bit to which the present invention is applied, wherein FIG. 3A is a partially cut-away side view, and FIG. 3B is a BB cross-sectional view thereof.

FIG. 4 is a side sectional view showing a wear mode of a teeth bit to which the present invention is applied.

5A and 5B are conceptual diagrams of a functionally gradient material used for the cutter bit of the present invention, wherein FIG. 5A is a composition diagram and FIG. 5B is a characteristic diagram.

6A and 6B are side views of a conventional tooth bit, wherein FIG. 6A shows an example of a cemented carbide chip bonding type, and FIG. 6B shows an example of a cemented carbide chip insertion type.

FIG. 7 is a view showing a conventional fish tail bit;
(A) is a partially cut-away side view, and (b) is a CC cross-sectional view thereof.

8A and 8B are views showing a conventional roller bit, in which FIG. 8A is a partially cut-away side view, and FIG. 8B is a sectional view taken along the line DD.

FIG. 9 is a view showing a form of wear of a conventional teeth bit.
(A) shows an example of a cemented carbide chip type, and (b) shows an example of a cemented chip insertion type.

FIGS. 10A and 10B are views showing a worn form of a conventional fishtail bit, wherein FIG. 10A is a partially cut-away side view, and FIG. 10B is a cross-sectional view taken along the line C′-C ′.

FIG. 11 is a view showing a wear mode of a conventional roller bit.
(A) is a partially cut-away side view, and (b) is its D'-D '
It is sectional drawing.

FIG. 12 is a front end sectional view of the shield machine showing a mounted state of the cutter bit.

[Explanation of symbols]

2 ... teeth bit, 3 ... fish tail bit, 4
... Roller bit, 7: Functionally graded material, 8: Carbide, 9 ...
Base material.

Claims (3)

(57) [Claims] 1. A tip and a rake connected from the tip
Cutter bit for earth and sand excavation having a face and a back face
At least the tip of the cutter bit, rake face
And the back surface, the composition of the cemented carbide and the base metal is changed continuously.
Characterized by the fact that it is formed from a functionally graded material
Cutter bits for soil drilling to. 2. A cutter for earth and sand digging comprising a functionally graded material obtained by laminating a raw material powder of a cemented carbide and a raw material powder of a base material with a predetermined composition gradient, forming, sintering and fusing. bit. 3. The cutter bit for earth and sand digging according to claim 1, wherein the surface layer portion of the cutter bit from the tip to the rake face and the back face is formed of a superhard material.