Patent ID: 8657609

Claim:
A seal structure for an electronic control device having a circuit board to which, at one side thereof, a connector is fixed and a housing having a pair of members that sandwich the connector in a thickness direction, and a part of the connector being exposed to an outside of the housing and a remaining part of the connector and the circuit board being housed in a watertight space of an inside of the housing, the seal structure comprising: a seal portion formed at a fitting surface portion between an outer peripheral surface of the connector and an inner peripheral surface of the housing in a circumferential direction of the connector, and provided with a seal groove formed at one side of the outer peripheral surface of the connector and the inner peripheral surface of the housing and a protruding line formed at the other side, a gap defined by fitting of the protruding line and the seal groove being filled with a sealant, and the seal portion having (a) a deep bottom portion where a seal groove having a predetermined depth is formed; (b) a shallow bottom portion whose seal groove is set to be shallower than the seal groove of the deep bottom portion; and (c) a connecting portion which connects the deep bottom portion and the shallow bottom portion, and a width of the seal groove of the shallow bottom portion being set to be large as compared with the deep bottom portion so that a seal length is constant between the deep bottom portion, the shallow bottom portion and the connecting portion, and as a position of a seal groove of the connecting portion gets closer to the deep bottom portion from the shallow bottom portion, a depth of the seal groove of the connecting portion being set to be gradually larger, and a width of the seal groove of the connecting portion being set to be gradually smaller.