abutment with the boot 92 and with the flange portion of the boot 92 made of elastic mateial such as rubber being closely abutted with the hole of the cable outlet part of the motor cover 41 and the cable 54 the boot 92 and the connector cover 88 are inserted into the end of the cable outlet of the motor cover 41 and in abutment therewith the boot 92 is closely encased by a metallic cover 93 and machine screws 57 with sealing means extending through the bores provided for the screws at the cover 93 and the flange of the boot 92 and are screwed into cable seat 56 of the motor cover 41 and fastened thereto the cable 54 is a standard type cable the end of which initially is not within a molded element the cover 93 the boot 92 and the connector cover 88 are first put over the cable then the core wires 54a are peeled off of the end of the cable 54 and tied to the terminals 62 of the connector 87 subsequently the connector cover 88 is slid along the cable 54 downwardly to be fitted to the connector 87 in this condition a filling agent 95 of such materials as resin or the.