Patent ID: 9139221
Filing Date: 2015-09-22
Classification: B23K,B62D,F16H,Y10T

Abstract:
1. A method of producing a rack for use in an electric power steering device of a vehicle, comprising: preparing a first bar piece that has first rack teeth adapted to be meshed with a first pinion directly driven by a steering wheel, a second bar piece that has second rack teeth adapted to be meshed with a second pinion driven by a steering assist electric motor and an intermediate piece that has one end to be welded to the first bar piece and the other end to be welded to the second bar piece; aligning the first bar piece, the intermediate piece and the second bar piece in order along a common axis; carrying out a first process in which the first and second bar pieces are stationarily held while having a predetermined intersection angle between the first rack teeth on the first bar piece and the second rack teeth on the second bar piece; and carrying out a second process in which each of the first and second bar pieces and the intermediate piece are brought into contact with each other at mutually facing ends and subjected to a relative rotation therebetween for friction welding, to thereby join the first bar piece, the intermediate piece and the second bar piece together by the friction welding, wherein the first process includes a step for fixing the first and second bar pieces to first and second pressing devices in such a manner as to have a relative angular displacement therebetween, and wherein the second process includes a step for rotating the intermediate piece at a given high speed about the common axis relative to the fixed first and second bar pieces.