JPS609609A - Drilling tool - Google Patents

Abstract

PURPOSE:To permit high-speed cutting for a material having a high hardness by taking account of the consitution of the cutting edge in which high-pressure phase sintered body is used as the material for a cutting tip. CONSTITUTION:A flute groove 2 is formed in the axial direction of a rod-shaped tool body 1, and a cutting edge tip 4 is installed into a tip seat 3 concaved at the top edge part of the flute groove, and on one side of the cutting edge tip 4, the front-surface side cutting edge 7 forms the circular center part cutting edge 8 having a round rake face in the vicinity of the center of revolution of the cutting edge 7. The center part cutting edge 8 is formed onto a center side tip 9 which has a nearly 1/4 disc form and is made of high-pressure phase sintered body, and the rest front surface cutting edge 7 is formed onto the outer peripheral side tip 12 in which the thin layer 11 made of high-pressure phase sintered body is sintered and fixed onto the base 10 made of superhard alloy. Thus, high- speed cutting is permitted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drilling tool, and in particular, improves cutting performance by rationally mounting a cutting tip equipped with a high-pressure phase sintered body such as cubic boron nitride or diamond. The aim is to

Conventionally, this type of drilling tool was manufactured by, for example, the Japanese Patent Publication No. 58-181.
63, Japanese Patent Publication No. 58-22283, etc. are disclosed. These tools have shown excellent cutting performance as a drilling tool for steel cutting due to their cutting edge configuration, formation of non-cutting zones, etc.

However, the development of tools that further improve the drilling efficiency is being pursued in terms of the cutting blade configuration and the material of the cutting blade tip.

The present invention has been made in view of the above points, and in particular, from the material aspect of the cutting edge tip, a cutting edge tip equipped with a high-pressure phase sintered body such as cubic boron nitride or diamond is applied, and the cutting edge configuration is It can be mounted on the tool body in a rational manner while taking into consideration the following, and enables high-speed cutting and cutting of high-hardness materials.

An embodiment of the drilling tool of the present invention will be described below with reference to the drawings.

Figures 1 and 2 show a single-blade slow 7-way drill, where (1) is a rod-shaped tool body;
A flute groove (2) is formed in the axial direction, and a cutting edge tip (4) is provided in a tip seat (3) recessed at the tip thereof. This cutting edge tip (4)
As shown in the figure, the center mounting can be done by using a hole (5) and a set screw (6), or by various means such as an eccentric pin or a presser foot.

This cutting edge tip (4) has a substantially square plate shape, and when placed in the tip seat (3), a front side cutting edge ridge (7) is formed at the negative side thereof.

In this case, the front side cutting edge ridge (7) has its rake face rounded near the center of rotation, thereby forming an arc-shaped central cutting edge ridge (8).

This center cutting edge (8) is formed by positioning a center tip (9) in the shape of an approximately 1/4 disk made of a high-pressure phase sintered body such as cubic boron nitride or diamond. The front cutting edge ridge (7) is an outer peripheral tip (L side is located The thin layer αυ is sintered and fixed by using a high temperature and high pressure generator.

These center tips (9) and outer peripheral tips α are integrated together with the support piece a3 to form a cutting edge tip (4).In this case, integration is usually performed by brazing.

Figure 3 shows a modification of the cutting edge tip (4).
The center cutting edge (8) of the center tip (9) is formed by a bent straight line because its rake face is chamfered in multiple steps. The center chip (9) is made by sintering and fixing a thin layer (IQ) of a high-pressure phase sintered body on a cemented carbide base I, and placing this thin layer a9 on the flank side. However, this thin layer αQ may be located on the rake face side similarly to the outer chip Q3.

Therefore, there are two types of center side tip (9): one is made of only a high-pressure phase sintered body, and the other is a case where a thin layer α9 made of a high-pressure phase sintered body is sintered and fixed to a base I of cemented carbide.

Furthermore, Fig. 4 to Fig. 6 show a two-blade brazing type twist drill, in which the tool body (221) has two cutting blades involved in drilling. The tip (c) (2) is brazed.The cutting edge tip e3) has an approximately 1/4 circular center tip cra.
b and an outer chip Qω.

By the way, the twist drill shown in Figures 4 to 6 is
There is a gap between the cutting blade tips (c) and (c), and the presence of this gap prevents the growth of the core generated from the workpiece material. Therefore, the width at which core growth is inhibited is important, and is generally selected from the range of 0.2 to 2.5B. However, the present invention is not limited to the twist drill shown in this embodiment, but can also be applied to a twist drill in which the starting end of the cutting edge starts from the center of rotation, as shown in Japanese Patent Publication No. 58-18163, for example.

Further, the drilling tool of the present invention can also be applied to a solid boring head as shown in No. 7rXJ and a spade drill as shown in FIGS. 8 and 9.

In Fig. 7, the cylindrical tool body (31) has a cutting tip C.
3 and guide pad 0■ are brazed, and this cutting edge tip C3 becomes the cutting edge tip of the twist drill mentioned above (
Same as 2), center side chip <34) and outer peripheral side chip (
It is composed of three parts.

In Figures 8 and 9, the tool body (41) is installed with a cutting tip (4) inserted into the groove (4
4). and,
This cutting blade tip (4 ri is a pair of front side cutting blade ridges (4!5
1, a center chip (46) and an outer peripheral chip (47) are brazed to one end of the support and integrated.

Therefore, the cutting edge tip (4
)? , : have commonality.

In the drilling tool of the present invention constructed in this manner, the cutting edge on the front side of the cutting edge tip is formed of a high-pressure phase sintered body made of cubic boron nitride, etc., and the cutting edge curve has a so-called spiral shape. Since it has a rectangular shape, high-speed cutting is possible. It also has the advantage of providing excellent cutting performance when cutting high-hardness materials and heat-resistant materials, and can be expected to extend tool life.

[Brief explanation of drawings]

Fig. 1 is a front view showing one embodiment of the drilling tool of the present invention, Fig. 2 is a bottom view thereof, Fig. 3 is an enlarged perspective view showing a modification of the cutting tip, and Figs. 4 to 6 are drilling tools. Fig. 4 shows a partial front view of the tool, Fig. 5 shows a bottom view thereof, Fig. 6 shows a partial side view of the tool, and Fig. 7FM shows a bottom view of another modification. 8 and 9 show another modification, with FIG. 8 being a partial front view and FIG. 9 being a bottom view thereof. (1) (23C31) (4υ... Tool body (4
) (To) lc32f43... Cutting blade tip (9)
(Foundation) (Foundation) (46) ... Center side chip aa (
2sesn... Outer chip patent applicant: Toshiba Tungaloy Co., Ltd./Figure

Claims (1)

[Claims] The cutting tip attached to the tip of the tool body has at least a front cutting edge, and near the center of rotation, the rake face on the cutting surface is rounded or chamfered in multiple steps. , a drilling tool in which a center cutting edge ridge having an arc shape or a plurality of bent straight lines is added, the cutting edge tip having a cubic crystal shape at least in a portion where the center cutting edge ridge is formed; A roughly 1/4 disk-shaped central tip made of a high-pressure phase sintered body of boron nitride, diamond, etc. is located, and the high-pressure phase is placed on a cemented carbide base in the portion that forms the remaining front cutting edge. A drilling tool characterized by forming a thin layer of a phase sintered body and having an outer tip positioned such that the thin layer is on the rake face side.