	US 12,303,986 B2
	Rotating tool with coolant hole
Akira Sato, Tokyo (JP)
Assigned to MITSUBISHI MATERIALS CORPORATION, Tokyo (JP)
Appl. No. 17/417,522
Filed by MITSUBISHI MATERIALS CORPORATION, Tokyo (JP)
PCT Filed Dec. 23, 2019, PCT No. PCT/JP2019/050266 § 371(c)(1), (2) Date Jun. 23, 2021, PCT Pub. No. WO2020/137937, PCT Pub. Date Jul. 2, 2020.
Claims priority of application No. 2018-242586 (JP), filed on Dec. 26, 2018; and application No. 2019-198973 (JP), filed on Oct. 31, 2019.
Prior Publication US 2022/0111450 A1, Apr. 14, 2022
Int. Cl. B23B 51/06 (2006.01); B23C 5/28 (2006.01)

CPC B23B 51/068 (2022.01) [B23B 51/0686 (2022.01); B23C 5/282 (2022.02)]

7 Claims

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,

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.