Drill
AssigneeSumitomo Electric Hardmetal Corp.
InventorsTeppei MIYAGAWA, Kouki MATSUBARA
Life of this patent
Estimating the term…
Abstract
When viewed along a central axis, a start point phase of a first discharge flute falls within a range of not less than +10° and not more than +90° with respect to a central edge, an end point phase of the first discharge flute falls within a range of not less than −40° and not more than 0° with respect to the central edge, a start point phase of a second discharge flute falls within a range of not less than +10° and not more than +90° with respect to an outer peripheral edge, and an end point phase of the second discharge flute falls within a range of not less than −40° and not more than 0° with respect to the outer peripheral edge. The first discharge flute includes a first front flute portion, and a first rear flute portion contiguous to the first front flute portion.
Claims9
A drill that rotates about a central axis, the drill comprising:
- a first cutting insert having a central edge;
- a second cutting insert having an outer peripheral edge;
- and
- a body to which the first cutting insert and the second cutting insert are attached, wherein
- the body is provided with a first discharge flute that discharges chips cut by the central edge, and a second discharge flute that discharges chips cut by the outer peripheral edge,
- when viewed along the central axis,
- a start point phase of the first discharge flute falls within a range of not less than +10° and not more than +90° with respect to the central edge,
- an end point phase of the first discharge flute falls within a range of not less than −40° and not more than 0° with respect to the central edge,
- a start point phase of the second discharge flute falls within a range of not less than +10° and not more than +90° with respect to the outer peripheral edge, and
- an end point phase of the second discharge flute falls within a range of not less than −40° and not more than 0° with respect to the outer peripheral edge,
- the first discharge flute includes a first front flute portion, and a first rear flute portion contiguous to the first front flute portion,
- the second discharge flute includes a second front flute portion, and a second rear flute portion contiguous to the second front flute portion,
- a helix angle of the first front flute portion monotonously decreases toward the first rear flute portion,
- a helix angle of the second front flute portion monotonously decreases toward the second rear flute portion,
- a helix angle of each of the first rear flute portion and the second rear flute portion is 0°,
- at a boundary between the first front flute portion and the first rear flute portion, values each calculated by dividing an amount of change in the helix angle of the first discharge flute by an amount of change in position in a direction along the central axis are continuous,
- at a boundary between the second front flute portion and the second rear flute portion, values each calculated by dividing an amount of change in the helix angle of the second discharge flute by an amount of change in position in the direction along the central axis are continuous,
- the body is provided with a first pocket portion that is contiguous to the first discharge flute and that is located forward with respect to a rotational direction of the first cutting insert, and
- in the direction along the central axis, a distance from a front end of the first cutting insert to a rear end of the first pocket portion is greater than or equal to 1.5 times a tool diameter.
Dependencies are inferred from the claim text.