MANUFACTURE OF SEALED TYPE RHEOSTAT

PURPOSE:To manufacture a small-sized sealed type rheostat capable of ensuring high reliability by shaving in a protruding section formed to the circumferential section of the outer surface of an insulating plate and one part of the inwall of a box-shaped ease through heat fusion and bringing the surface of the shaving clearance to a rough state, etc., through heat fusion. CONSTITUTION:When a thermoplastic insulating plate 26 is fixed to a box-shaped case 21 composed of a thermoplastic insulating material and sealed with a sealing resin 28, a protruding section 26d formed to the circumferential section of the outer surface of the insulating plate 26 and one part of the inwall of the box-shaped case 21 are shaven in through heat fusion, and the whole circumference of the outer circumferential surface of the insulating plate 26 is covered with the shaving clearance 21f of the box-shaped case 21 and the insulating plate 26 is fixed to the box-shaped case 21 while heat is applied to at least one part of the protruding section 26d of the insulating plate 26 and at least one part of the protruding section 26d is melted. The surface of the shaving clearance 21f shaven in from the inwall and at least the top face of the protruding section 26d of the insulating plate 26 are brought to a rough state from the initial state of fabrication through heat fusion, and the opening section 21b of the box-shaped case 21 and the outer surface of the insulating plate 26 are molded with the insulating sealing resin 26 including the welding section of the shaving clearance 21f of the box-shaped case 21 and the welding section of the protruding section 26d of the insulating plate 26.