HEATING RESISTANCE TYPE AIR FLOW RATE MEASURING APPARATUS AND FIXING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To prevent dropping of a sub-air passage and, if dropping, prevent change of the output characteristic of a heating resistance type air flow rate measuring apparatus by providing a protrusion at a part of a dropping stopper, etc., so as to contact a part of the sub-air passage. SOLUTION: A main air passage 1 is provided with a stopper 11 for blocking a sub-air passage from dropping off. A protrusion 12 is attached thereto. The protrusion 12 is sharp at the top end and fixed to the sub-air passage surface in a collapsed shape when a circuit module 13 is fixed to the main air passage 1. Thus the sub-air passage is perfectly fixed to make it possible to avoid dropping the sub-air passage and avoid changing the output value due to the positional deviation from a sensor.