Patent ID: 7293457
Filing Date: 2007-11-13
Classification: G01F

Abstract:
1. A flow rate measuring apparatus comprising: a measuring passage through which passes a portion of a fluid being measured flowing through a main passage; a flow rate detecting element in which a sensor portion is formed on a front surface of a flat substrate, said flow rate detecting element being disposed such that said sensor portion is exposed inside said measuring passage; a circuit board on which a control circuit is mounted for driving said sensor portion and processing a signal therefrom; a connector portion for sending and receiving signals between said circuit board and an external portion; a resin base, said connector portion being formed integrally on said base, said connector portion being positioned outside said main passage and said base projecting inside said main passage; and a metal plate supported by said base, said metal plate being disposed inside said main passage so as to be substantially parallel to a direction of flow of said fluid being measured through said main passage, wherein: said circuit board is disposed on said metal plate so as to be positioned substantially in a common plane with a front surface of said metal plate, said flow rate detecting element is positioned substantially in a common plane with said front surface of said metal plate and disposed on said metal plate in close proximity to an opposite end of said circuit board from said connector portion, a circuit housing portion is disposed on said front surface of said metal plate so as to surround said circuit board, an electrical connection portion between said circuit board and said flow rate detecting element, and an electrical connection portion between said circuit board and said connector portion, a cover is mounted so as to cover said circuit housing portion, a measuring passage groove forming portion is disposed on a front surface of said metal plate at an opposite end of said circuit housing portion from said connector portion and functions together with said metal plate to constitute said measuring passage, and said circuit housing portion and said measuring passage groove forming portion are formed integrally on said base.