Hitachi, Ltd.

Hitachi Car Engineering Co., Ltd.

Nobuhito Hiramatsu

Shinya Igarashi

Naoki Saito

Hiromu Kikawa

Masayuki Kozawa

A thermal type air flow measuring instrument has a molded part formed by integral molding with a metal plate. A slot or opening allowing only a resin to pass through the same is formed in the metal plate in an area subjected to higher stresses. A part of the connector terminals are disposed in the vicinity of an area where the resin has a larger thickness and the temperature difference between the inside and the outside of the resin is locally increased. The injecting direction is set to prevent a weld line and a void from being generated. For the molded part with the metal plate inserted therein, the occurrence of cracks is minimized. Further, an increase of the fatigue crack growth rate is decreased.

Thermal type flow measuring instrument with mold casing in metal insert

The invention is intended to improve reliability of a thermal type air flow measuring instrument employing a molded part formed by integral molding together with a metal plate. A slot or opening allowing only a resin to pass through the same is formed in the metal plate in an area or thereabout subjected to higher stresses. A part of connector terminals, which is not required from the intrinsic object, is disposed in the vicinity of a area where the resin has a larger thickness and the temperature difference between the inside and the outside of the resin is locally increased. An injecting direction is set so as to prevent a weld line and a void from being generated in a combined way. In the molded part with the metal plate inserted therein, the occurrence of cracks and an increase of the fatigue crack growth rate can be suppressed and reliability can be improved.

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Hitachinaka, Japan

Nobuhito Hiramatsu