Abstract: A breaker (1) is provided with: a fixed piece (2) which has a fixed contact; a movable piece which has a movable contact at a front end portion and pushes the movable contact against the fixed contact to bring same into contact with each other; a thermally responsive element that deforms in accordance with a change in temperature and thereby actuates the movable piece so that the movable contact separates from the fixed contact; and a case body (71) of a resin case that accommodates the fixed piece (2), the movable piece, and the thermally responsive element. The case body (71) has recess portions (75, 77) which are recessed from a peripheral portion, and the fixed piece (2) has a withdrawal portion (25) that withdraws from the recess portions (75, 77) of the case body (71) by a predetermined first distance (D1) or more, and is embedded in the case body (71).

Abstract: A circuit breaker 1 comprises: a fixed-contact piece 2 with a fixed contact 21; a movable-contact piece 4 with a movable contact 41; a thermal actuator element 5 thermally transformable to move the movable-contact piece; a PTC thermistor 6 for conducting electricity between the movable-contact piece 4 and the fixed-contact piece 2; a main body 71 of a package provided with a holding recess 73 housing the above-mentioned components; and a cover 81 hermetically covering the holding recess 73. The fixed-contact piece 2 is embedded between an internal wall 74 and an external wall 75 of the main body 71. The PTC thermistor 6 is housed in an opened hollow 73d. In a planar view of the circuit breaker, a through-hole 76 penetrating through the external wall 75 overlaps with the opened hollow 73d, but does not overlap with the centroid O of the opened hollow 73d.

Abstract: A breaker is provided with: a movable piece (4) that has an elastically deformable elastic portion (43) and a movable contact on the tip of the elastic portion (43) and that presses the movable contact into contact with a fixed contact; a thermal actuator element (5) that is formed into a shape with a convex surface and is deformed by a change in temperature, thereby actuating the movable piece (4) so that the movable contact separates from the fixed contact; and a resin case (7) which houses the movable piece (4) and the thermal actuator element (5). The bottom surface of the base end (42a) of the movable piece (4) is positioned lower than the top (5a) of the upper surface of the thermal actuator element (5) by a distance (D). Thereby, a stable temperature adjustability and a resistance value are ensured in a breaker used as a protection device for a secondary battery with miniturization brought into realty.

Abstract: An electric part 100 comprises a terminal piece 102 having an embedded portion 103 embedded in a resinous package 101 and a projecting portion 104 projecting from the package 101 and having a tip end 102e. The projecting portion 104 is provided with a bent section 110 including a first bent position 111 and a second bent position 112. Between the first bent position 111 and the second bent position 112, a diverging position 120 is disposed such that the projecting portion 104 is divided into two or more parts from the diverging position 120 toward the tip end 102e.

Abstract: A circuit breaker 1 comprises: a fixed-contact piece 2 with a fixed contact 21; a movable-contact piece 4 with a movable contact 41; a thermal actuator element 5 thermally transformable to move the movable-contact piece so that the movable contact 41 and the fixed contact 21 are opened; a PTC thermistor 6 for conducting electricity between the movable-contact piece 4 and the fixed-contact piece 2 through the thermal actuator element 5 when the movable contact 41 and the fixed contact 21 are opened; a main body 71 of a package provided with a holding recess 73 housing the above-mentioned components; and a cover 81 hermetically covering the holding recess 73. The fixed-contact piece 2 is embedded between an internal wall 74 and an external wall 75 of the main body 71. The PTC thermistor 6 is housed in an opened hollow 73d penetrating through the internal wall 74 under such a state that the PTC thermistor 6 conductively contacts with the fixed-contact piece 2.

Abstract: A breaker is provided with: a movable piece (4) that has an elastically deformable elastic portion (43) and a movable contact on the tip of the elastic portion (43) and that presses the movable contact into contact with a fixed contact; a thermal actuator element (5) that is formed into a shape with a convex surface and is deformed by a change in temperature, thereby actuating the movable piece (4) so that the movable contact separates from the fixed contact; and a resin case (7) which houses the movable piece (4) and the thermal actuator element (5). The bottom surface of the base end (42a) of the movable piece (4) is positioned lower than the top (5a) of the upper surface of the thermal actuator element (5) by a distance (D). Thereby, a stable temperature adjustability and a resistance value are ensured in a breaker used as a protection device for a secondary battery with miniturization brought into realty.

Abstract: A breaker (1) is provided with: a fixed piece (2) which has a fixed contact; a movable piece which has a movable contact at a front end portion and pushes the movable contact against the fixed contact to bring same into contact with each other; a thermally responsive element that deforms in accordance with a change in temperature and thereby actuates the movable piece so that the movable contact separates from the fixed contact; and a case body (71) of a resin case that accommodates the fixed piece (2), the movable piece, and the thermally responsive element. The case body (71) has recess portions (75, 77) which are recessed from a peripheral portion, and the fixed piece (2) has a withdrawal portion (25) that withdraws from the recess portions (75, 77) of the case body (71) by a predetermined first distance (D1) or more, and is embedded in the case body (71).

Abstract: A digging-into portion 91 formed in a fixed part 42 of a movable piece 4 digs into and fits with a protrusion 74a of a resin casing 71, and the movable piece 4 is firmly fixed to the resin casing 71. Thereby, the posture of the movable piece 4 relative to the resin casing 71 is stabilized, and the positional relation between the fixed contact and the movable contact is stabilized.