Cutting insert having varying rake angle and variable-width land, and cutting tool

Patent metadata

Field	Value
Publication number	US-10131002-B2
Application number	US-201515313109-A
Country	US
Kind code	B2
Filing date	May 25, 2015
Priority date	May 26, 2014
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A polygonal cutting has opposing first and second end surfaces connected by a side surface, and a plurality of cutting edges formed between the end surfaces and the side surface. Each cutting edge is formed at corner and includes a corner cutting edge and a major cutting edge connected to the corner cutting edge. A rake surface formed along the cutting edge on first the end surface is inclined toward the second end surface. In a side view of the cutting insert, the major cutting edge includes an inclined part which is inclined so as to approach the second end surface from the corner cutting edge. A portion of the rake surface along the inclined part is formed such that an angle of inclination toward the second end surface increases toward the corner in a direction along the intersecting edge between the first end surface and the side surface.

First claim

What is claimed is:

1. A cutting insert, comprising:
a first end surface and a second end surface opposing the first end surface;
a side surface connecting the first end surface and the second end surface; and
at least one cutting edge extending on an intersecting edge between the first end surface and the side surface, each cutting edge of the at least one cutting edge including:
a corner cutting edge extending at a corner of the first end surface; a major cutting edge connected to the corner cutting edge; and a minor cutting edge connected to the corner cutting edge on an opposite side of the cutting corner from the major cutting edge, wherein:
the first end surface is provided with a rake surface along a respective cutting edge of the at least one cutting edge, the rake surface being inclined toward the second end surface as a distance from the respective cutting edge the at least one cutting edge increases;
in a side view of the cutting insert, the major cutting edge includes an inclined part which is inclined so as to approach the second end surface from the corner cutting edge;
a portion of the rake surface along the inclined part is formed such that an angle of inclination with respect to the second end surface increases as the portion of the rake surface along the inclined part approaches the corner in a direction along the intersecting edge between the first end surface and the side surface;
as viewed from a top view of the first surface end, the major cutting edge has a first major cutting edge portion and a second major cutting edge portion that forms an obtuse interior angle (θ) with the first major cutting edge portion, the first major cutting edge portion is connected to the corner cutting edge, and the second major cutting edge portion extends on a side, opposite to the corner cutting edge, of the first major cutting edge portion;
the inclined part extends from the first major cutting edge portion to part of the second major cutting edge portion; and
the first end surface is provided with a land between the respective cutting edge of the at least one cutting edge and the rake surface, such that a width of a portion of the land adjacent to the major cutting edge becomes larger as the portion of the land approaches the corner with which the major cutting edge is associated; wherein
in the land, a width of a portion of a first land extending between the first major cutting edge portion and the rake surface increases as the portion of the first land approaches the corner; and
a width of a portion of a second land extending between the second major cutting edge portion and the rake surface increases as the portion of the second land approaches the corner.

2. The cutting insert according to claim 1 , wherein, in the side view of the cutting insert, the major cutting edge is curved so as to be recessed toward the second end surface and approaches closest to the second end surface in the second major cutting edge portion.

3. The cutting insert according to claim 1 , wherein a rate of increase of the width of the first land is larger than a rate of increase of the width of the second land.

4. The cutting insert according to claim 1 , wherein the first major cutting edge portion is shorter than the second major cutting edge portion.

5. The cutting insert according to claim 1 , wherein:
as viewed from the direction facing the first end surface, an interior angle (γ) of the corner is smaller than the interior angle (θ) between the first major cutting edge portion and the second major cutting edge portion.

6. The cutting insert according to claim 1 , further comprising a through hole that penetrates the first end surface and the second end surface, wherein:
the at least one cutting edge is a number N cutting edges extending on the intersecting edge between the first end surface and the side surface are arranged in a rotational N-fold symmetry about a central axis of the through hole based on the number of cutting edges; and
the cutting insert is 180-degree rotationally symmetric about an axis that is orthogonal to the central axis of the through hole.

7. The cutting insert according to claim 1 , wherein:
a first inclined surface and a second inclined surface are formed in the side surface, the second inclined surface being arranged on a second end surface side with respect to the first inclined surface and located apart from the first inclined surface in a circumferential direction of the cutting insert;
the first inclined surface is inclined so as to face an inner side of the cutting insert as a distance to the second end surface decreases; and
the second inclined surface is inclined so as to be located on the inner side of the cutting insert as a distance to the first end surface decreases.

8. An indexable polygonal cutting insert comprising:
an upper surface, a lower surface, a side surface connecting the upper and lower surfaces, a middle plane (M) midway between the upper and lower surfaces, and a through hole connecting the upper and lower surfaces and having a center axis (A 1 ) of rotational symmetry;
a plurality of cutting edges formed between the upper surface and the side surface, each cutting edge of the plurality of cutting edges being associated with a corner of the polygonal insert and including:
a corner cutting edge;
a major cutting edge connected to a first side of the corner cutting edge;
a minor cutting edge connected on a second side of the corner cutting edge opposite from the major cutting edge;
a rake surface provided on the upper surface along said each cutting edge, the rake surface being inclined in a direction of the lower surface; and
a land located between said each cutting edge and the rake surface;

wherein:
in a top view of the cutting insert:
the major cutting edge has a first major cutting edge portion connected to a second major cutting edge portion, the first major cutting edge portion being closer to the corner cutting edge than the second major cutting edge portion, the first major cutting edge portion forming an obtuse interior angle (θ) with the second major cutting edge portion; and
a portion of the land adjacent to the major cutting edge becomes larger as the portion of the land approaches the corner with which the major cutting edge is associated;

in a side view of the cutting insert:
the major cutting edge includes an inclined part which is inclined from the corner cutting edge in a direction of the lower surface, the inclined part extending from the first major cutting edge portion to part of the second major cutting edge portion;

along the inclined part of the major cutting edge, a portion of the rake surface has an angle of inclination with respect to the lower surface which increases as the portion of the rake surface along the inclined part approaches the corner with which the major cutting edge is associated;
the land includes a first land extending between the first major cutting edge portion and the rake surface;
the land includes a second land extending between the second major cutting edge portion and the rake surface; and
widths of portions of the first and second lands both increase as the portions of the first and second lands approach the corner.

9. The cutting insert according to claim 8 , wherein, in the side view of the cutting insert:
the corner is further from the middle plane (M) than; the second major cutting edge portion of each major cutting edge.

10. The cutting insert according to claim 8 , wherein a rate of increase of the width of the first land portion is larger than a rate of increase of the width of the second land.

11. The cutting insert according to claim 8 , wherein the fi

Assignees

• Tungaloy Corp

Inventors

• Matsumura Takahiro
• Yoshida Satoru

Classifications

• B23C2200/291

  Variable rake angles · CPC title

• B23C5/202

  Plate-like cutting inserts with special form (special form related to securing of the insert B23C5/22) · CPC title

• B23C2200/125

  discontinuous · CPC title

• B23C2210/168

  Seats for cutting inserts, supports for replacable cutting bits · CPC title

• B23C2200/208

  Wiper, i.e. an auxiliary cutting edge to improve surface finish · CPC title