Abstract: A bearing oil feeding amount is appropriately controlled with respect to specifications of a discharge pressure (bearing load) and a rotation speed.

Abstract: A cutting insert that has, in an upper surface, a convex portion including a main portion having a flat upper end surface, a first portion projecting from the main portion to a corner portion of the upper surface, a second portion projecting from the first portion to the corner portion, and a third portion projecting from the second portion to the corner portion. Upper end heights of the second portion and the third portion are fixed toward the corner portion, respectively. The first portion and the second portion are connected by a first flat inclined wall surface, the second portion and the third portion are connected by a second wall surface of a convex curved surface, and a front end of the third portion and the breaker groove are connected by a third wall surface of a convex curved surface.

Abstract: A cutting insert of an embodiment includes a cutting edge located at an intersecting part of an upper surface and a side surface. The cutting edge includes a corner cutting edge, a major cutting edge, and a flat cutting edge. The upper surface includes a first land surface located along the corner cutting edge, a second land surface located along the major cutting edge, and a third land surface located along the flat cutting edge. A maximum value of a width of the third land surface is smaller than a maximum value of a width of each of the first land surface and the second land surface in a top view.

Abstract: A cutting insert of one embodiment is provided with: an insert body having a top surface that has a corner section, a bottom surface, and side surfaces; a cutting edge that is positioned at an intersection between the top surface and the side surfaces, and includes a corner cutting edge, a first cutting edge and a second cutting edge; a rake face that slopes downward away from the cutting edge; and a first raised part that is positioned inside the rake face, and rises upward. The first raised part includes a protruding section that protrudes toward the corner cutting edge. The cutting insert is further provided with a second raised part that extends toward the first cutting edge and the second cutting edge from the protruding section, and has a convex curved shape in which, when viewed from above, the outer peripheral edge on the corner section side.

Abstract: A cutting insert of an embodiment includes a cutting edge located at an intersecting part of an upper surface and a side surface. The cutting edge includes a corner cutting edge, a major cutting edge, and a flat cutting edge. The upper surface includes a first land surface located along the corner cutting edge, a second land surface located along the major cutting edge, and a third land surface located along the flat cutting edge. A maximum value of a width of the third land surface is smaller than a maximum value of a width of each of the first land surface and the second land surface in a top view.

Abstract: A bearing oil feeding amount is appropriately controlled with respect to specifications of a discharge pressure (bearing load) and a rotation speed.

Abstract: A cutting insert of one embodiment is provided with: an insert body having a top surface that has a corner section, a bottom surface, and side surfaces; a cutting edge that is positioned at an intersection between the top surface and the side surfaces, and includes a corner cutting edge, a first cutting edge and a second cutting edge; a rake face that slopes downward away from the cutting edge; and a first raised port that is positioned inside the rake face, and rises upward. The first raised part includes a protruding section that protrudes toward the corner cutting edge. The cutting insert is further provided with a second raised part that extends toward the first cutting edge and the second cutting edge from the protruding section, and has a convex curved shape in which, when viewed from above, the outer peripheral edge on the corner section side.

Abstract: A cutting insert includes an insert body including an upper surface, a lower surface, a side surface connected to each of the upper surface and the lower surface, and a cutting edge located at an intersection of the upper and side surfaces. The insert body is divided into cutting and fixing sections. A region of the upper surface located at the cutting section includes a rake surface which is located further inward than the cutting edge and is inclined as going inward at an inclination angle ?1 with respect to a reference plane perpendicular to a central axis, and a plurality of protruded parts arranged along the cutting edge. Each of the plurality of protruded parts includes a first surface which is inclined as going inward at an inclination angle with respect to the reference plane and has a larger width as going inward in a top view.

Abstract: A cutting insert that has, in an upper surface, a convex portion including a main portion having a flat upper end surface, a first portion projecting from the main portion to a corner portion of the upper surface, a second portion projecting from the first portion to the corner portion, and a third portion projecting from the second portion to the corner portion. Upper end heights of the second portion and the third portion are fixed toward the corner portion, respectively. The first portion and the second portion are connected by a first flat inclined wall surface, the second portion and the third portion are connected by a second wall surface of a convex curved surface, and a front end of the third portion and the breaker groove are connected by a third wall surface of a convex curved surface.

Abstract: A cutting insert includes an insert body including an upper surface, a lower surface, a side surface connected to each of the upper surface and the lower surface, and a cutting edge located at an intersection of the upper and side surfaces. The insert body is divided into cutting and fixing sections. A region of the upper surface located at the cutting section includes a rake surface which is located further inward than the cutting edge and is inclined as going inward at an inclination angle ?1 with respect to a reference plane perpendicular to a central axis, and a plurality of protruded parts arranged along the cutting edge. Each of the plurality of protruded parts includes a first surface which is inclined as going inward at an inclination angle with respect to the reference plane and has a larger width as going inward in a top view.