| 摘要 |
<p>PURPOSE:To obtain uniformly hardened surfaces without the need for polishing after hardening by oscillating the work and coils relatively with each other in the stage of hardening the internal recessed parts of a cylindrical shape simultaneously in the plural places at a prescribed width in the axial direction of the cylinder. CONSTITUTION:A cooler 40 for cooling outisde circumference, the work and coils 10 are concentrically disposed to position cooling boxes 41, the surfaces 51 to be hardened and coils 11 oppositely to each other. The work 50 is then rocked by a rocking mechanism in the directions of broken line arrows with respect to the coils 11 and when the coils 11 are energized with high frequency current, the surfaces 51 facing to the coils 11 are inductively heated but both rock relatively with each other and therefore the surfaces are uniformly heated over the set width of rocking. The supply of the high frequency current is interrupted upon ending of the heating; at the same time, the surfaces 51 are quickly cooled by the refrigerant injected from the ejection ports 16 of the non- metallic jackets 15 erected at the center, whereby the surfaces 51 are heated uniformly at the desired width and length.</p> |
