JPH0379213U

JPH0379213U -

Info

Publication number: JPH0379213U
Application number: JP13861989U
Authority: JP
Priority date: 1989-12-01
Filing date: 1989-12-01
Publication date: 1991-08-13

Description

[Brief explanation of the drawing]

第１図ないし第４図は本考案の一実施例を示し
、第１図は切欠部中心角１０°の場合の斜視図、
第２図は第１図の−断面図、第３図、第４図
は切欠部中心角が９０°および１８０°の場合の
それぞれ横断面図、第５図、第６図は試験例１お
よび２のそれぞれ結果を示すグラフ、第７図は従
来型コアドリルによる穴明け作業状態を示す縦断
面図、第８図は先行技術のコアドリルの側面図、
第９図は第８図の−断面図である。１……ドリル本体、３……先端面、４……内径
面、５……外径面、６……切欠部、７……側端縁
、７ａ……外径側面取り面、８……側端縁、８ａ
……内径側面取り面。 1 to 4 show an embodiment of the present invention, and FIG. 1 is a perspective view when the central angle of the notch is 10°;
Figure 2 is a cross-sectional view of Figure 1, Figures 3 and 4 are cross-sectional views when the center angle of the notch is 90° and 180°, respectively, and Figures 5 and 6 are Test Example 1 and Figure 6. 2 is a graph showing the results of 2, FIG. 7 is a vertical cross-sectional view showing the state of drilling with a conventional core drill, and FIG. 8 is a side view of the prior art core drill.
FIG. 9 is a cross-sectional view of FIG. 8. DESCRIPTION OF SYMBOLS 1... Drill body, 3... Tip surface, 4... Inner diameter surface, 5... Outer diameter surface, 6... Notch, 7... Side edge, 7a... Outer diameter chamfered surface, 8... Side edge, 8a
...Inner diameter chamfered surface.

Claims

[Scope of utility model registration request]

The approximately cylindrical drill body has a notch extending in the axial direction from the distal end surface to the side surface, and the leading side edge of the notch in the direction of rotation of the drill is chamfered on the outer diameter side, and the trailing side edge is chamfered. A core drill whose inner diameter side is chamfered so that cooling water is sent into the inner diameter side as the drill rotates, and hard abrasive grains are fixed to the entire surface of the drill body.