METHOD AND APPARATUS FOR SURFACE HARDENING THE WORK SURFACES OF A MULTIPLICITY OF CAMS

摘要

Method and apparatus for simultaneously surface heat treating the wear surfaces of a multiplicity of cams (24-27) on a camshaft (4) by transferring to the cam surfaces the energy of a concentrated beam (14) of electrons. The electron beam (14) is directed for a predetermined time to a desired spot on the surface of the said cams (24-27) and is caused to move incrementally from one to the next of a predetermined matrix of spots (28-31) on the work surface as the camshaft (4) is being rotated. After the predetermined matrix pattern (28-31) has been repeated one or more times, the beam (14) is then directed sequentially from one cam (24) to the next (25) and the process repeated until all wear surfaces on the cams have been treated. The predetermined pattern (28-31) is projected over the desired surface of all the cams (24-27) a predetermined number of times so that the material to be heat treated at the intersection of the plane described by the beams's motion and all the cam surfaces being in effect, simultaneously heat treated is brought above the transformation temperature by close control of the electron beam (14) parameters. The beam power and dwell time of the beam at each point are programmed in accordance with the linear velocity of the particular cam surface being instantaneously treated in such a way that the instantaneous energy per increment of surface of each of the cams is made to follow a predetermined law of instantaneous energy input vs. angular position of the cam. Each heat element along the surface of the cam as it moves from under the beam is rapidly cooled by the underlying mass of cold material to effect a quench.