THERMAL AIR FLOWMETER

• Main Authors: OGATA KIMITOSHI, ISHIZUKA NORIO, TASHIRO SHINOBU, DOI RYOSUKE
• Format: Patent
• Language: English; Japanese
• Published: 26.01.2017
• Subjects: MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; METERING BY VOLUME; PHYSICS; TESTING

PROBLEM TO BE SOLVED: To provide a thermal air flowmeter having improved measuring accuracy.SOLUTION: There is provided a thermal air flowmeter, which includes: a sensor chip 4 which is arranged in the sub-passage and measures a flow rate of a fluid to be measured, the sensor chip 4 having a cavity portion 28 formed on a semiconductor substrate and a diaphragm 27 formed so as to cover the cavity portion; a circuit portion 3 which converts a fluid flow rate detected by the sensor chip into an electric signal; a connector portion which is electrically connected to the circuit portion and outputs the signal to the outside; a housing which supports the sensor chip and the circuit portion; a plate 2 on which the sensor chip is mounted; and a lead frame 1 on which the plate is mounted. The sensor chip and the plate are molded by a resin 24 such that the diaphragm of the sensor chip and a part of the plate are exposed, the plate has an air passage 13 for making the rear face of the diaphragm portion communicate with outside of a sensor assembly, and the air passage is formed in an inner side than a portion pressed against the sensor chip in a transverse direction of the plate.SELECTED DRAWING: Figure 3 【課題】計測精度を向上させた熱式空気流量計を提供する。【解決手段】半導体基板に形成された空洞部２８と、空洞部を覆うように形成されたダイアフラム２７とを有し、副通路に配置され被計測流体の流量を計測するセンサチップ４と、センサチップにより検出した流体流量を電気信号に変換する回路部３と、回路部と電気的に接続され外部に信号を出力するコネクタ部と、センサチップ及び回路部を支持する筐体と、センサチップが実装されるプレート２と、プレートが実装されるリードフレーム１を有する熱式空気流量計において、センサチップ及びプレートはセンサチップのダイアフラム及びプレートの一部が露出するように樹脂２４でモールドされ、プレートは、ダイアフラム部裏面をセンサアセンブリ外部と連通するための空気通路１３を有しており、空気通路はプレートの短手方向におけるセンサチップに押しつけられる箇所よりも内側に形成されている。【選択図】図３