| CPC B23B 27/16 (2013.01) [B23B 1/00 (2013.01); B23B 2200/088 (2013.01); B23B 2200/165 (2013.01); B23B 2205/12 (2013.01)] | 13 Claims |
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1. A cutting insert, comprising:
an upper surface;
a lower surface located on a side opposite to the upper surface;
a front lateral surface located between the upper surface and the lower surface;
a rear lateral surface located between the upper surface and the lower surface and located on a side opposite to the front lateral surface;
a first lateral surface located between the upper surface and the lower surface and located between the front lateral surface and the rear lateral surface; and
a second lateral surface located between the upper surface and the lower surface, located between the front lateral surface and the rear lateral surface, and located on a side opposite to the first lateral surface,
the upper surface comprising
a first upper cutting edge located on an intersection with the front lateral surface, and
an upper constraining surface which is located closer to the rear lateral surface than the first upper cutting edge, and which is contactable with a holder,
the lower surface comprising a lower constraining surface contactable with the holder,
the lower constraining surface comprising a lower groove having a V-shape extended from a side of the front lateral surface toward the rear lateral surface,
the lower groove comprising
a first region located on a side opposite to the upper constraining surface,
a second region located closer to the front lateral surface than the first region, and
a third region located closer to the rear lateral surface than the first region,
the lower groove further comprising a first portion and a second portion which are opposed to each other with a bottom of the lower groove interposed therebetween, and which are contactable with the holder, wherein
the first portion is closer to the first lateral surface than the bottom of the lower groove and comprises a first outer edge extending along the first lateral surface,
the second portion is closer to the second lateral surface than the bottom of the lower groove and comprises a second outer edge extending along the second lateral surface,
a length of a line segment connecting the first outer edge and the second outer edge in the first region is a first length, a length of a line segment connecting the first outer edge and the second outer edge in the second region is a second length, and a length of a line segment connecting the first outer edge and the second outer edge in the third region is a third length in a cross section orthogonal to an extending direction of the lower groove,
the first length is larger than each of the second length and the third length,
the upper constraining surface comprises an upper groove having a V-shape extended from a side of the front lateral surface toward the rear lateral surface,
the upper groove is extended parallel to the lower groove,
the upper groove comprises a third portion and a fourth portion which are opposed to each other with a bottom of the upper groove interposed therebetween, and which are contactable with the holder,
the third portion is closer to the first lateral surface than the bottom of the upper groove and comprises a third outer edge extending along the first lateral surface,
the fourth portion is closer to the second lateral surface than the bottom of the upper groove and comprises a fourth outer edge extending along the second lateral surface,
a length of a line segment connecting the third outer edge and the fourth outer edge is a fourth length in a cross section orthogonal to an extending direction of the upper groove, and
the first length is larger than the fourth length.
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