To improve the construction of a resin frame for suppressing thermal interference between heater units by securing high heat shielding performance between partition walls, while reducing the thickness of each of the interphase partition walls by adopting the thermoplastic resin for the resin frame which stores the heater units arranged in R, S, T phases from side to side.
In the thermal overload relay, the heater units 1 of main bimetals 2 connected to the R, S, T phases of a main circuit and an output contact mechanism linked to the main bimetals 2 in the phases are mounted on the boxed resin frame 14 as a molded resin product. Inside the resin frame 14, erected chambers storing the individual heater units 1 in the phases are defined from side to side via the interphase partition walls 14a. Each of the interphase partition walls 14a has a region on the side of a supporting portion supporting at least the base of the heater unit 1, formed with a double wall 14d sandwiching an intermediate air layer 14c, resulting in improved interphase heat insulting performance.
COPYRIGHT: (C)2011,JPO&INPIT
TOYAMA KENTARO
TADA SHINJI
MORISHITA FUMIHIRO
FURUHATA YUKIO
