Abstract: A resistance heater 134 for detecting an air flow rate is supported by support members 134A, 134B. A housing 110 contains an electronic circuit 140 connected to the resistance heater 134. The housing 110 is formed by integral molding with a terminal 142 for connecting the electronic circuit 140 to an external device. The terminal 142 is formed integrally with the housing 110. The housing 110 has a groove 112 through which the terminal 142 is exposed in part.

Abstract: An air temperature detector 12 is disposed close to an auxiliary passage sidewall 15, which has an auxiliary passage wall hole 9 formed near the air temperature detector 12. A heat-sensitive resistor 13 is also disposed close to the auxiliary passage sidewall 15, which has an auxiliary passage wall hole 10 formed near the heat-sensitive resistor 13. Further, a resistor heater 14 is disposed close to an auxiliary passage sidewall 16, which has an auxiliary passage wall hole 11 near the resistor heater 14.

Abstract: Resin members, on the surfaces of which metal films are formed, are used for; an auxiliary air passage provided in a main air passage, in which a sensor element of a physical quantity sensor such as an air flow sensor, an intake-air temperature sensor, etc., is situated; a housing; and so forth; in order to decrease both the thermal conductivity and the emissivity of those components to respective small values, whereby the temperature increase of the sensor due to both the heat conduction and the heat radiation can be suppressed.

Abstract: The invention is intended to improve reliability of a thermal type air flow measuring instrument employing a molded part formed by integral molding together with a metal plate. A slot or opening allowing only a resin to pass through the same is formed in the metal plate in an area or thereabout subjected to higher stresses. A part of connector terminals, which is not required from the intrinsic object, is disposed in the vicinity of a area where the resin has a larger thickness and the temperature difference between the inside and the outside of the resin is locally increased. An injecting direction is set so as to prevent a weld line and a void from being generated in a combined way. In the molded part with the metal plate inserted therein, the occurrence of cracks and an increase of the fatigue crack growth rate can be suppressed and reliability can be improved.

Abstract: To correct properly the error of the thermal resistor type air flow measuring apparatus caused by the pulsation in the intake pipe in detecting the air flow of the internal combustion engine, a thermal resistor is placed in a passage inside the auxiliary air passage into which the reverse flow hardly flows directly and the error caused by the reverse flow is prevented. The existence of the reverse flow is judged by the ratio of the amplitude to the mean value using the maximum value, the minimum value and the mean value of the forward air flow waveform, and the error caused by the increase of the forward air flow is corrected.

Abstract: The thermal-type airflow meter comprises airflow meter body 86 and measuring part 87. Both of the frame 31 of the housing 3 accommodating therein the electronic circuit 6 and the subpassage member 4 having the heating resistor 1 etc. positioned within a subpassage of air are arranged on the metallic base 5. Further, the frame 31, the subpassage member 4, the metallic base 5 and the cover 9 are adhered to respectively different member more than one. The connector 32 of the housing 3, the frame 31 and the subpassage member 4 are formed in a flat shape to form the measuring module 87. The measuring module 87 is inserted through the insertion hole 83 to locate the heating resistor 1 within the main air passage 81, and the fixing flange 36 of the housing 3 is fixedly attached to the airflow meter body 86.

Abstract: Resin members, on the surfaces of which metal films are formed, are used for; an auxiliary air passage provided in a main air passage, in which a sensor element of a physical quantity sensor such as an air flow sensor, an intake-air temperature sensor, etc., is situated; a housing; and so forth; in order to decrease both the thermal conductivity and the emissivity of those components to respective small values, whereby the temperature increase of the sensor due to both the heat conduction and the heat radiation can be suppressed.

Abstract: A thermal-type airflow meter comprises an airflow meter body and a measuring part. Both of the frame of a housing which accommodates the electronic circuit, and a sub-passage member which has the heating resistor positioned within a sub-passage, are arranged on a metallic base. Further, the frame, the sub-passage member, the metallic base and the cover are each fixedly attached to at least two respective different members. A connector of the housing, the frame and the sub-passage member are formed in a flat shape to form the measuring module. The measuring module is inserted through an insertion hole to locate the heating resistor within the main air passage, and the fixing flange of the housing is fixedly attached to the airflow meter body.

Abstract: A thermal-type airflow meter comprises an airflow meter body and a measuring part. Both of the frame of a housing which accommodates the electronic circuit, and a sub-passage member which has the heating resistor positioned within a sub-passage, are arranged on a metallic base. Further, the frame, the sub-passage member, the metallic base and the cover are each fixedly attached to at least two respective different members. A connector of the housing, the frame and the sub-passage member are formed in a flat shape to form the measuring module. The measuring module is inserted through an insertion hole to locate the heating resistor within the main air passage, and the fixing flange of the housing is fixedly attached to the airflow meter body.