Patent ID: 7963161
Filing Date: 2011-06-21
Classification: G01F

Abstract:
1. A heat resistor type air flow rate measuring device comprising: an auxiliary passage taking in a part of fluid flowing in a main passage; and a plate-shaped sensor element for detecting a flow rate of the fluid being installed in the auxiliary passage, wherein the auxiliary passage is provided with an auxiliary passage inlet port and an auxiliary passage outlet port disposed in an intake pipe forming said main passage; the plate-shaped sensor element having a sensor formation surface being mounted on a board provided in the auxiliary passage, the board having the sensor formation surface of the plate-shaped sensor element being arranged so as to intersect a phantom plane substantially perpendicularly, the phantom plane being located parallel to the flow direction in the intake pipe, and the auxiliary passage being arranged along the phantom plane from the inlet port to the outlet port; the auxiliary passage forms a curved line from the inlet port to the plate-shaped sensor element having a curvature of 90° or more along the phantom plane upstream of the plate-shaped sensor element; and the sensor formation surface and a rear side of the board opposite to the sensor formation surface form gaps from an auxiliary passage wall surface.