Rotating tool with coolant hole

Patent metadata

Field	Value
Publication number	US-12303986-B2
Application number	US-201917417522-A
Country	US
Kind code	B2
Filing date	Dec 23, 2019
Priority date	Dec 26, 2018
Publication date	May 20, 2025
Grant date	May 20, 2025

Abstract

In a rotating tool with a coolant hole, a coolant hole extending to a front side in the direction of an axis opening to a tip flank face of a drill main body that is rotated around the axis. In a cross section orthogonal to the axis, the coolant hole is provided with a first concavely curved portion located on an inner peripheral side of the drill main body and formed in a concavely curved shape recessed to the inner peripheral side, a second concavely curved portion located on an outer peripheral side of the drill main body and formed in a concavely curved shape recessed to the outer peripheral side with a larger curvature radius than the first concavely curved portion, two third concavely curved portions having a center of a curvature radius located inside the coolant hole with a smaller curvature radius than the second concavely curved portion.

First claim

What is claimed is:

1. A rotating tool with a coolant hole, comprising:
a rotating tool main body configured to be rotated in a tool rotation direction around an axis,
wherein
a chip discharge flute that opens to a front end surface of the rotating tool main body and extends to a rear side is formed at an outer periphery of a front portion of the rotating tool main body,
a cutting edge, in which a wall surface of an inner wall face of the chip discharge flute facing the tool rotation direction is used as a rake face and the front end surface of the rotating tool main body connected to the rake face is used as a tip flank face, is formed at a front side ridge portion of the wall surface,
a coolant hole that extends toward a front side in an axis direction in the rotating tool main body opens to at least one of the tip flank face and the inner wall face of the chip discharge flute,
wherein
in a cross section orthogonal to the axis, the coolant hole is provided with
a first concavely curved portion located on an inner peripheral side of the rotating tool main body and formed in a concavely curved shape recessed to the inner peripheral side,
a second concavely curved portion located on an outer peripheral side of the rotating tool main body so as to face the first concavely curved portion and formed in a concavely curved shape recessed to the outer peripheral side with a larger curvature radius than a curvature radius of the first concavely curved portion,
two third concavely curved portions being in contact with two end portions of the second concavely curved portion, respectively, having a center of a curvature radius located inside the coolant hole with a smaller curvature radius than that of the second concavely curved portion, extending to a center side of the rotating tool main body, and being recessed in a circumferential direction, and
two portions connecting an end portion of the first concavely curved portion to the end portion of the third concavely curved portion that is not in contact with the second concavely curved portion,

wherein
in the cross section orthogonal to the axis,
the coolant hole as a symmetrical shape via a straight line, the straight line being orthogonal to the axis of the rotating tool main body and passing through a center of the first concavely curved portion,
the coolant hole is formed such that a width thereof in the circumferential direction gradually increases toward the outer peripheral side of the rotating tool main body in the first concavely curved portion and the two portions, and
the coolant hole is formed such that the width thereof in the circumferential direction is gradually reduced toward the outer peripheral side of the rotating tool main body in the third concavely portion,

wherein
either
the two portions form straight lines in the cross section orthogonal to the axis,
or
the two portions form concave curves recessed to an outside of the coolant hole in the cross section orthogonal to the axis,
in the cross section orthogonal to the axis, a distance along a direction orthogonal to a direction where the straight line extends of distances between the two portions, is set such that an increasing rate is gradually decreased by each unit length toward the outer peripheral side of the rotating tool main body in the direction where the straight line extends.

2. The rotating tool with a coolant hole according to claim 1 ,
wherein a ratio r 1 /r 3 of a curvature radius r 1 of the first concavely curved portion to a curvature radius r 3 of the two third concavely curved portions is in a range of 0.5 to 2.0.

3. The rotating tool with a coolant hole according to claim 1 ,
wherein the first concavely curved portion is in contact with a circle having a radius of 0.05×D or more with respect to a diameter D of the cutting edge about the axis in the cross section orthogonal to the axis.

4. The rotating tool with a coolant hole according to claim 1 ,
wherein a curvature radius of the second concavely curved portion is 0.42×D or less with respect to a diameter D of the cutting edge in the cross section orthogonal to the axis.

5. The rotating tool with a coolant hole according to claim 1 ,
wherein the two portions form straight lines in the cross section orthogonal to the axis.

6. The rotating tool with a coolant hole according to claim 1 ,
wherein the two portions form concave curves recessed to the outside of the coolant hole in the cross section orthogonal to the axis.

7. The rotating tool with a coolant hole according to claim 6 , imaginary straight lines connect each of the end portions of the first concavely curved portion and the end portion of each of the third concavely curved portions not in contact with the second concavely curved portion,
a circle is inscribed on the second concavely curved portion and the imaginary lines,
in the cross section orthogonal to the axis, a maximum amount by which the concave curves bulge with respect to the imaginary lines is in a range of 5% or less of a diameter of the circle.

Assignees

• Mitsubishi Materials Corp

Inventors

• Sato Akira

Classifications

• B23C5/28

  Features relating to lubricating or cooling · CPC title

• B23B51/0686 Primary

  Cross-sectional shape of coolant hole · CPC title

• B23C5/282

  Coolant channel characterised by its cross-sectional shape · CPC title

• B23B51/068 Primary

  Details of the lubricating or cooling channel · CPC title