Patent ID: 8641335

Claim:
An apparatus for forming recesses on a circumferential surface that defines a cylindrical bore in a workpiece, the apparatus comprising: a tool holder disposed coaxially with the cylindrical bore and rotatably about a rotation axis; a form roller support retained on the tool holder, the form roller support being moveable in a direction perpendicular to the rotation axis of the tool holder; a form roller rotatably supported on the form roller support so as to be rotatable about a rotation axis that is parallel to the rotation axis of the tool holder, the form roller comprising projections on an outer circumferential surface thereof which are configured to form the recesses on the circumferential surface that defines the cylindrical bore in the workpiece; and a control assembly configured to control the form roller support such that the form roller is allowed to be in press contact with the circumferential surface that defines the cylindrical bore in the workpiece at a press contact load of a predetermined value on the basis of a centrifugal force which is exerted on the form roller support and the form roller during rotation of the tool holder.