JPH04187575A - Production of diamond core bit - Google Patents

Abstract

PURPOSE:To improve joining strength and load resistance from the side by irradiating the joining face between a cylindrical body and arc-like diamond blade with laser beam or electron beam to form tapered fillet part. CONSTITUTION:The tip of cylindrical body 1 is brought into contact with an arc-like diamond blade 2 and the joining face is continuously irradiated with laser beam or electron beam from the arrow (a) to melt whole the circumference in the vicinity of the joining face. Then the joining face is melted and solidified and tapered fillet (b) is formed in at least either one of outside or inside of diamond core bit to bond the body 1 to diamond blade 2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a method for manufacturing a diamond core bit suitable for drilling operations.

[Background of the idea]

Generally, a diamond core bit 4 has a plurality of arc-shaped diamond cutting blades 2 fixed at intervals to the end face of a cylindrical body 1, as shown in FIG. It is used as a work material in drilling work in concrete, rock, asphalt, brick, etc. in dry or wet state.

Conventionally, this type of diamond core bit 4 is shown as A in FIG.
As shown in FIG. 2, which is a cross-sectional view of part -A', a diamond cutting blade 2 was fixed to the end face of the body 1 using a brazing material C by brazing. This diamond cutting blade is a sintered product made of a composite of metal powder made of metal bond and diamond abrasive grains.

To manufacture diamond cutting blades, diamond abrasive grains are sintered at a temperature that will not be damaged by heat. Generally 6
Since the molding is performed at a sintering temperature of 50 to 1100°C, when fixing the diamond cutting blade to the body, it is necessary to use silver brazing material at a temperature lower than the sintering temperature so as not to impair the performance of the diamond cutting blade. The row material was made using

However, as drilling work becomes more demanding than before and a large amount of work is performed in a short period of time, the thrust force applied to the diamond core bit or lateral loads such as bending and torsion act on the diamond core bit. begins to break at the joint. In addition, as the drilling speed increases, the effect of water cooling near the diamond cutting edge decreases even in wet conditions, and the temperature of the diamond cutting edge increases due to frictional heat with the workpiece and cutting heat. This will lead to a decrease in the strength of the diamond cutting edge, which will eventually lead to damage to the diamond cutting blade, resulting in a decrease in work efficiency.

[Purpose of the invention]

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the prior art, to make it easy to manufacture by fixing a diamond cutting blade to the body, to have sufficiently high bonding strength, and to sufficiently withstand lateral loads. The efficiency of drilling work has been improved,
An object of the present invention is to provide a method for manufacturing a diamond core bit with high bonding strength.

[Summary of the invention]

A feature of the present invention is that in a diamond core bit in which a plurality of arc-shaped diamond cutting blades are fixed at intervals to the tip of a cylindrical body, when joining the cylindrical body and the arc-shaped diamond cutting blade, The surface is continuously irradiated with a laser beam or an electron beam to melt the vicinity of the joint between the body and the diamond cutting blade to form a tapered fillet, thereby fixing the body and the diamond cutting blade. A method of manufacturing a diamond core bit is characterized by the following.

Next, embodiments of the present invention will be described with reference to the drawings.

FIGS. 3(a) and 3(b) are cross-sectional views illustrating an embodiment of the present invention, showing the steps of joining the diamond cutting blade and the body.

In Fig. 3(a), the diamond cutting blade 2 and the body 1 are butted against each other, and a laser beam or an electron beam is continuously irradiated onto the joint surface C from the direction of arrow a on the outside of the diamond core bit. The entire surrounding area is melted. next,
As shown in FIG. 3(b), the joint surfaces are melted and solidified to form a tapered fillet on at least one of the outside and inside of the diamond core bit. In this case, there is no step part at the joint like in brazing material, so there is no notch effect, and the strength is sufficiently high so that it can sufficiently withstand lateral loads. Even if a tapered fillet is formed using brazing material as in the past, the strength of the brazing material itself is much lower than the strength of the body, diamond cutting blade, and their joints, so it does not contribute to improving the joint strength. do not have. In addition, since no brazing material is used, the product of the present invention prevents the strength of the joint from decreasing due to temperature increases due to frictional heat and cutting heat generated between the diamond cutting blade and the rigid material during drilling operations. There will be no more invitations.

Generally, the body is made of a low-carbon steel pipe, which is advantageous because the body will not be hardened even when subjected to rapid heating and cooling by laser beams or electron beams. Since the joint is made of a mixture of the body components and the diamond cutting edge components, the mechanical strength is sufficiently high. Furthermore, since the vicinity of the joint is melted, the diamond cutting edge is not thermally damaged and has the advantage of ensuring sufficient quality. Furthermore, this joining process is relatively simple, and there is no need to activate the surfaces of the joining surfaces using flux such as brazing material.

〔Effect of the invention〕

As explained above, the present invention makes it easy to fix the diamond cutting blade to the body, has sufficiently high bonding strength, and can sufficiently withstand lateral loads during severe drilling work. This has the effect of improving work efficiency.

[Brief explanation of the drawing]

Figure 1 is a bottom view of the diamond core bit, Figure 2 is the conventional joint part A-A' in Figure 1, 1 is the body, 2 is the bottom view of the diamond core bit.
is the diamond cutting edge, 3 is the joint surface, 4 is the diamond core bit, a is the irradiation direction, b is the fillet part, and C is the brazing material.

Claims (1)

[Claims] In a diamond core bit in which a plurality of arc-shaped diamond cutting blades are fixed at intervals to the tip of a cylindrical body, when the cylindrical body and the arc-shaped diamond cutting blade are joined, the joining surface is exposed to laser beam light or electrons. A diamond core bit characterized in that a beam is continuously irradiated to melt the vicinity of the joint between the body and the diamond cutting blade to form a tapered fillet, thereby fixing the body and the diamond cutting blade. manufacturing method.