Seal structure for electric circuit unit

Abstract

A seal structure for an electric circuit unit is formed of an elastic material and includes an annular seal member mounted between an inner peripheral surface of an opening formed in a casing to pass a cable therethrough and an outer peripheral surface of the cable, a fixed member fixed on the casing at the opening, and a size-changing member formed with a through hole for allowing the cable to pass therethrough and adapted to change the size of the opening of the casing so as to fit the size of the outer periphery of the cable. The size-changing member is fixed in the opening, so that the fixed member is deformed by being held between the size-changing member and the fixed member, thereby bringing the seal member into close contact with the inner peripheral surface of the opening of the casing and the outer peripheral surface of the cable.

Description

technical field [0001] The present invention relates to a sealing structure of a circuit unit composed of a circuit, a case for protecting the circuit, and a cable connected to the circuit. Background technique [0002] The circuit unit includes: a circuit; a case for protecting the circuit; and a cable connected to the circuit for outputting an input signal or supplying power. Generally, for fixing and waterproofing the cables, a sealing structure 100 as shown in FIG. 9 is used for the portion leading the cables from the outside to the inside of the housing. Specifically, the casing 102 is provided with a stepped opening 106 composed of a small-diameter portion 106a and a large-diameter portion 106b through which the cable 104 passes, and an annular sealing member 108 composed of an elastic member such as a rubber sleeve is placed in the The large-diameter portion 106 of the opening 106 is fitted around the cable, and the fixing member 100 applies pressure to the sealing m...

AI Technical Summary

Problems solved by technology

However, in this case, as shown in FIG. 10 , when pressure is applied to the sealing member 108 by the fixing member 110 , pressure deformation is transferred to the inner peripheral surface of the small-diameter portion 106 a of the opening 106 and the outer peripheral surface of the cable 104 . Therefore, the pressure cannot be effectively applied to the inner peripheral surface of the small-diameter portion 106a of the opening 106 and the outer peripheral surface of the cable 104, and the sealing member 108 cannot be in close contact with them, making it difficult to ensure sufficient sealing performance.

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