Patent ID: 8677811

Claim:
An air flow rate measuring device adapted to be disposed in an intake passage leading to an engine, for taking in a part of air flowing through the intake passage and generating a heat transfer phenomenon between the device and the air taken in thereby to measure a flow rate of air suctioned into the engine, the device comprising: a housing that defines an internal flow passage, through which the air taken in passes, and that includes a contact surface; a sensor assembly that includes: a sensor chip that is configured to generate an electrical signal through the heat transfer phenomenon, wherein the sensor assembly is inserted and fixed in the housing such that the sensor chip is exposed to the internal flow passage; and a contact surface that is in surface contact with the contact surface of the housing; and an urging mechanism that is configured to press the contact surface of the sensor assembly which is on a sensor chip-side against the contact surface of the housing from a rear surface-side of the sensor chip, so that the sensor assembly is fixed to the housing by the urging mechanism, wherein: the housing further includes a hole, into which the sensor assembly is fitted; a part of a surface of the housing that defines the hole serves as the contact surface of the housing; a part of the surface of the housing that defines the hole serves as the urging mechanism; and the sensor assembly is press-fitted into the hole by the urging mechanism to be in press contact with a leading end of the urging mechanism and the contact surface of the housing.