Patent ID: 8002163

Claim:
A friction welding apparatus for friction welding a first work piece and a second work piece together by pressing the second work piece against the first work piece while rotating one of the work pieces relative to the other work piece, comprising: a first holder for holding the first work piece; a second holder for holding the second work piece; a thrust mechanism for moving the second holder toward or away from the first holder; a shaft connected to the first holder and the second holder for receiving thrust caused by the thrust mechanism, wherein the shaft has a tie rod and an externally threaded member which is coaxially connected to the tie rod wherein the externally threaded member is rotatable on an axis thereof and the tie rod is nonrotatable on the axis, wherein the thrust mechanism has the externally threaded member, an internally threaded member and a thrust motor such that the tie rod and the thrust motor are connected to opposite ends of the externally threaded member, wherein the internally threaded member is provided in either one of the first holder and the second holder and engaged with the externally threaded member, wherein the thrust motor rotates the externally threaded member relative to the internally threaded member, wherein one end of the externally threaded member is connected to one end of the tie rod so that the externally threaded member is rotatable on the axis and the other end of the externally threaded member receives power from the thrust motor.