JPH07269293A - Cutter bit - Google Patents

Abstract

PURPOSE:To enhance durability by defining the material of a cemented carbide tip for both ends of cutter bits as low hardness and high toughness out of cemented carbide tips installed in parallel to cutter bits and the material of a cemented carbide tip in the central part as high hardness and high toughness. CONSTITUTION:A tip mounting recessed part 14 is formed on the tip of a sheet- like base metal 13 which constitutes a mounting part of the base end. A plurality of cemented carbide tips 15, 16, 17 and 18 are fixed with the tip mounting recessed part 14 by brazing 16 in such a state that they may line up breadthwise. To braze with the tips 15 ad 18 on both ends, there is adopted a material having a low hardness and high toughness out of the cemented carbide tips 15, 16, 17 and 18. Then, when excavating a hard ground or the like by mounting a cutter bit 11 to a cutter head of a shield driving machine, a face pressure exerting on the chips 15 and 18 on both ends is reduced, thereby protecting the chips 15 and 18 from being damaged. Although the tips 15 and 18 are subjected to wear out during excavation work, the properties of the hardness and high toughness tips 16 and 17 prevents a drop in their wearing properties.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting bit for a tunnel excavator, a tunnel boring machine, a cutting tool for machine tools, a cutter for a road header, a cutter for a bucket wheel excavator, or a cutter for a boring machine. .

[0002]

2. Description of the Related Art FIG. 2 is a schematic perspective view of a conventional cutter bit,
FIG. 3 is a schematic perspective view showing a damaged state of a conventional cutter bit.

As shown in FIG. 2, a conventional cutter bit 1
In 01, a chip mounting recess 104 is formed at the tip of a plate-shaped base metal 103 whose base end is the mounting part 102.
One chip 105, 106, 107, 108 is fixed by brazing 109 in a line. Then, the plurality of chips 105, 106, 107, 108
Each of them is generally a cemented carbide tip with high durability.

[0004]

When the cutter bit 101 as described above is mounted on, for example, the cutter head of a tunnel excavator to excavate the ground, a plurality of aligned chips 10 are arranged.
Of the 5, 106, 107, 108, a large amount of load is applied to the chips 105, 108 at both ends in the width direction. And in the above-mentioned conventional cutter bit 101,
Cemented carbide chips 105, 106, 107 with high durability,
Although equipped with 108, when excavating soil or hard ground mixed with gravel, these chips 105, 10
There is a problem in that a shocking load acts on 6, 107 and 108, and as shown in FIG. 3, a defect 110 is generated at the corners of the chips 105 and 108 at both ends in the width direction.

The present invention is intended to solve such problems, and an object of the present invention is to provide a cutting bit for cutting which is prevented from being damaged and improved in durability.

[0006]

In order to achieve the above object, a cutting cutter bit according to the present invention is fixed to a tip of a base metal in a state where a plurality of cemented carbide chips are arranged side by side in the width direction. In the cutting cutter bit, the material of the cemented carbide chips at both ends in the width direction of the plurality of cemented carbide chips arranged in parallel is made to have low hardness and high toughness.

[0007]

[Function] By making the material of the cemented carbide chips at both ends in the width direction of the plurality of cemented carbide chips arranged side by side in the base metal to have low hardness and high toughness, the chips at both ends can be processed under severe cutting conditions. The abrasion is promoted, the shape is rounded, the local surface pressure is reduced, and the stress is equalized, so that the fracture resistance is further improved.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a schematic perspective view of a cutting bit representing a cutting bit according to an embodiment of the present invention.

As shown in FIG. 1, in the cutter bit 11 of this embodiment, a tip mounting recess 14 is formed at the tip of a plate-shaped base metal 13 whose base end serves as the mounting portion 12. A plurality of chip mounting recesses 14 (4 in this embodiment)
The cemented carbide chips 15, 16, 17 and 18 are fixed by brazing 19 in a state of being aligned in the width direction.
Then, the plurality of cemented carbide chips 15, 16, 17,
A material having low hardness and high toughness is used for the chips 15 and 18 at both ends of the chip 18,
A material having high hardness and high toughness is used for 17.

Specifically, for materials having low hardness and high toughness,
The chips 15 and 18 thus formed have Vickers hardness HV.
= 900-1000, bending strength 350kgf / mm²JI above
Uses SE5 material with high hardness and high toughness
The formed chips 16 and 17 have Vickers hardness HV =
1100 to 1300, bending strength 250 to 350kgf / mm ²Since
It is suitable to use the above JIS E3 equivalent
It

Therefore, even when the cutter bit 11 is mounted on, for example, the cutter head of a tunnel excavator and excavation work is performed under severe conditions such as soil and hard ground where gravel is mixed, the tip 15 , 16, 17, 18 are made of a material having low hardness and high toughness for the tips 15 and 18 at both ends, the wear is accelerated against an impact load, resulting in a rounded shape. Chips 15, 18
The local surface pressure on the chip is reduced, the impact force is mitigated rather than the stress is equalized, and damage to the chips 15 and 18 is prevented.

Further, wear occurs in the tips 15 and 18 during excavation work, but since the tips 16 and 17 in the central portion among the tips 15, 16, 17 and 18 are made of a material having high hardness and high toughness. The wear resistance of the entire cutter bit does not decrease. Further, compared with the conventional cutter bit, the manufacturing method is not troublesome, and the material cost and the manufacturing cost are not increased.

[0014]

As described above in detail with reference to the embodiments, according to the cutting cutter bit of the present invention, a plurality of cemented carbide chips are arranged in the width direction at the tip of the base metal. Of the multiple cemented carbide tips that are fixed and arranged side by side, the material of the cemented carbide tips at both ends in the width direction has low hardness and high toughness, so if this cutter bit is used under severe cutting conditions, The abrasion of the tip of the portion is promoted and the shape is rounded, so that the local surface pressure is reduced, the stress is equalized, and the chipping is prevented and the durability can be improved.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of a cutting bit representing a cutting bit according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view of a conventional cutter bit.

FIG. 3 is a schematic perspective view showing a damaged state of a conventional cutter bit.

[Explanation of symbols]

 11 Cutter bit 13 Base metal 15,18 Low hardness and high toughness cemented carbide tip 16,17 High hardness and high toughness cemented carbide tip

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuyuki Okamoto 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (72) Inventor Shigeru Honnami Matsubara-shi Shindo, Osaka 3-16, Star Loy Industries Co., Ltd.

Claims (1)

[Claims] 1. A cutting cutter bit fixed to a tip of a base metal in a state in which a plurality of cemented carbide chips are arranged side by side in the width direction, the width among the plurality of cemented carbide chips arranged in parallel. A cutter head for a shield excavator, characterized in that the material of the cemented carbide tips at both ends in the direction is low hardness and high toughness.