INDEXABLE ROTARY CUTTING TOOL AND INSERT

• US 20190047062A1
• Filed: 08/19/2016
• Published: 02/14/2019
• Est. Priority Date: 02/12/2016
• Status: Active Grant

• Current Assignee: Mitsubishi Hitachi Tool Engineering,Ltd. (Mitsubishi Materials Corporation)
• Original Assignee: Mitsubishi Hitachi Tool Engineering,Ltd. (Mitsubishi Materials Corporation)
• Inventors: Kiuchi, Yasuhiro, Kobayashi, Yoshiyuki, Nakamigawa, Takao, Inagaki, Fumihiko, Hayashi, Yuuki
• Granted Patent: US 10,688,570 B2
• Time in Patent Office: Days
• CPC Class Codes: B23C 2200/0444 Pentagonal
• CPC Class Codes: B23C 2200/086 with one or more grooves
• CPC Class Codes: B23C 2200/203 Curved cutting edges
• CPC Class Codes: B23C 2200/243 bevelled or chamfered
• CPC Class Codes: B23C 2200/28 Angles
• CPC Class Codes: B23C 2200/283 Negative cutting angles
• CPC Class Codes: B23C 2200/284 Negative clearance angles
• CPC Class Codes: B23C 2200/326 by chip-breaking grooves
• CPC Class Codes: B23C 2200/361 Fixation holes
• CPC Class Codes: B23C 2210/0414 different
• CPC Class Codes: B23C 2210/0428 axial rake angle
• CPC Class Codes: B23C 2210/0435 radial rake angle
• CPC Class Codes: B23C 2210/045 axial rake angle
• CPC Class Codes: B23C 2210/0485 Helix angles
• CPC Class Codes: B23C 2210/082 Details of the corner region between axial and radial cutting edges
• CPC Class Codes: B23C 2210/084 Curved cutting edges
• CPC Class Codes: B23C 2210/123 Bevelled cutting edges
• CPC Class Codes: B23C 2210/503 mounted internally on the cutter
• CPC Class Codes: B23C 2210/74 Slits
• CPC Class Codes: B23C 2250/16 Damping vibrations balancing B23C2250/04
• CPC Class Codes: B23C 5/003 : with vibration suppressing means
• CPC Class Codes: B23C 5/109 : with removable cutting inserts
• CPC Class Codes: B23C 5/2208 : for plate-like cutting inserts B23C5/2226, B23C5/2234 take precedence

Abstract

An indexable rotary cutting tool comprising, a twist angle of the outer peripheral cutting edge having a positive value, an axial rake angle of the cutting edge of the corner R at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value, the axial rake angle of the cutting edge of the corner R at the reference point has a negative value, at least the radial rake angle in a region between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value, and the radial rake angle of the cutting edge of the corner R at the reference point is smaller than the radial rake angle of the cutting edge of the corner at the boundary point.

Claims

1. An indexable rotary cutting tool comprising:

a tool body; and

an insert having a cutting edge portion, the insert being detachably mounted on a mounting seat provided at a tip end portion of the tool main body,

wherein the mounting seat includes;

a insert fit groove in a slit shape which is formed at the tip end portion of the tool main body to extend in a radial direction orthogonal to a rotation center axis including a tool rotation center axis; and

a clamp screw configure to fix the insert inserted into the insert fit groove,

wherein the cutting edge portion of the insert includes;

an outer peripheral cutting edge which extends along the rotation center axis direction;

a rake face of the outer peripheral cutting edge;

a bottom cutting edge which extends along the radial direction;

a rake face of the bottom cutting edge;

a cutting edge of a corner R which connects an outer end of the bottom cutting edge in the radial direction to a front end of the outer peripheral cutting edge in the rotation center axis direction and is formed in an arc shape to protrude toward an outer peripheral side of the tip end portion of the tool main body;

a rake face of the cutting edge of the corner R;

a chamfered surface which is formed in at least the rake face of the cutting edge of the corner R;

a chip removal groove which is formed at a base end side of the rake face of the bottom cutting edge in the rotation center axis direction; and

a chip removal groove which is formed at the inside of the rake face of the outer peripheral cutting edge in the radial direction, and

wherein, within a virtual plane, which is perpendicular to a reference plane including a predetermined point on the cutting edge of the corner R and the rotation center axis; and

includes a virtual straight line passing through an arc center point of the cutting edge of the corner R and the predetermined point, a true rake angle corresponding to an angle in which the rake face of the cutting edge of the corner R is inclined with respect to the reference plane is defined as a radial rake angle,

an angle in which the virtual straight line projected to the reference plane is inclined with respect to the rotation center axis within the reference plane is defined as a radial angle,

a point in which the virtual straight line inclined by the radial angle of 5°

intersects the cutting edge of the corner R is defined as a reference point, and wherein

a twist angle of the outer peripheral cutting edge has a positive value,

an axial rake angle of the cutting edge of the corner R at a boundary point between the cutting edge of the corner R and the outer peripheral cutting edge has a positive value,

the axial rake angle of the cutting edge of the corner R at the reference point has a negative value,

at least the radial rake angle in a region between the boundary point and the reference point in an entire edge length region of the cutting edge of the corner R has a negative value, and

the radial rake angle of the cutting edge of the corner R at the reference point is smaller than the radial rake angle of the cutting edge of the corner R at the boundary point.

2. The indexable rotary cutting tool according to claim 1,

wherein the radial rake angle is set to a negative value in the entire edge length region of the cutting edge of the corner R.

3. The indexable rotary cutting tool according to claim 1,

wherein the chamfered surface includes the entire edge length region of the cutting edge of the corner R.

4. The indexable rotary cutting tool according to claim 1,

wherein the chamfered surface extends in the rake face of the outer peripheral edge beyond the boundary point between the cutting edge of the corner R and the outer peripheral cutting edge toward a base end side in the rotation center axis direction from the rake face of the cutting edge of the corner R.

5. The indexable rotary cutting tool according to claim 4,

wherein a length in which the chamfered surface extends toward the base end side in the rotation center axis direction from the boundary point between the cutting edge of the corner R and the outer peripheral cutting edge equals to or more than 0.02 r and equal to or smaller than 0.5 r in a condition that a radius of the cutting edge of the corner R is indicated by r.

6. The indexable rotary cutting tool according to claim 1,

wherein the chamfered surface extends in the rake face of the bottom cutting edge beyond the boundary point between the cutting edge of the corner R and the bottom cutting edge inward in the radial direction from the rake face of the cutting edge of the corner R.

7. The indexable rotary cutting tool according to claim 1,

wherein a rotationally most projecting point which protrudes furthest toward a tool rotation direction in a circumferential direction about the rotation center axis is disposed on the cutting edge of the corner R among the cutting edge of the corner R and the outer peripheral cutting edge, and

wherein the rotationally most projecting point is disposed in a range of the radial angle of 40°

or more and 55°

or less on the cutting edge of the corner R.

8. The indexable rotary cutting tool according to claim 1,

wherein a size of the axial rake angle of the cutting edge of the corner R at the boundary point between the cutting edge of the corner R and the outer peripheral cutting edge is 90% or more and 110% or less in a condition that a size of the twist angle of the outer peripheral cutting edge is 100%.

9. The indexable rotary cutting tool according to claim 1,

wherein the radial rake angle has a maximum value in a region located between the reference point and the boundary point between the outer peripheral cutting edge and the cutting edge of the corner R in the cutting edge of the corner R.

10. An insert which is used in the indexable rotary cutting tool according to claim 1.