Air flow measuring device

摘要

An air flow measuring device includes a housing, a sensor, and a throttle that is provided on an outer wall surface of the housing. The throttle merges together a bypass-passing flow and an outside-passing flow, and guides the merged flow toward the downstream side with the merged flow narrowed. The throttle includes two raised portions and a cover that bridges between the two raised portions and is opposed to the outer wall surface of the housing. The cover includes an inner surface exposed to the throttle, and an outer surface exposed to outside of the throttle. A peripheral border of the cover includes an upstream edge which defines the outer surface on the upstream side. At least a region of the outer surface including the upstream edge is swollen more outwardly in a shape of a projecting curved surface further on the downstream side.

主权项

1. An air flow measuring device that is adapted to be disposed in an intake passage through which intake air drawn into an internal combustion engine flows and that is configured to take in a part of intake air flowing through the intake passage and to produce an electrical signal which is in accordance with a flow rate of intake air in the intake passage, the air flow measuring device comprising:
a housing that defines a bypass flow passage through which the taken-in intake air passes; a sensor that is accommodated in the bypass flow passage and is configured to generate the electrical signal as a result of heat transfer between the taken-in intake air and the sensor; and a throttle that is provided on an outer wall surface of the housing and is configured to merge together a bypass-passing flow out of an outlet of the bypass flow passage via the bypass flow passage and an outside-passing flow in a flow direction of intake air in the intake passage along the outer wall surface of the housing without passing through the bypass flow passage and to guide the merged flow toward a downstream side in the flow direction of intake air in the intake passage with the merged flow narrowed, the throttle including:
two raised portions that are raised from the outer wall surface of the housing with the outlet located therebetween; anda cover that bridges between the two raised portions and is opposed to the outer wall surface of the housing, wherein: the cover includes an inner surface exposed to the throttle, and an outer surface exposed to outside of the throttle; a peripheral border of the cover includes an upstream edge which defines the outer surface on an upstream side in the flow direction of intake air in the intake passage; and at least a region of the outer surface including the upstream edge is swollen more outwardly in a shape of a projecting curved surface further on the downstream side in the flow direction of intake air in the intake passage.