Abstract: A knee protecting airbag device in which a folded airbag and an inflator are housed and held in a case. In the inflator, a connection portion to be connected with a connector having leadwires connected is exposed to the outside of the case through insert holes formed in the airbag and in the case. The through hole of the case has an internal diameter size smaller than the external diameter size of the general portion of the inflator near the connection portion of the inflator.

Abstract: A pressure sensor for detecting a pressure such as a brake oil pressure in an automobile is composed of a cylindrical stem, a sensor chip and a circuit board for processing an electrical signal from the sensor chip. The cylindrical stem includes a thin diaphragm formed at an axial end and an opening formed at the other axial end. The sensor chip is mounted on the diaphragm, and the circuit board is mounted on a flat side surface formed on the outer periphery of the cylindrical stem so that the circuit board is positioned perpendicularly to the sensor chip, thereby reducing a size of the pressure sensor in the radial direction of the stem. The pressure to be detected is introduced into the cylindrical stem from its opening, and the pressure is detected by the sensor chip mounted on the diaphragm.

Abstract: An acceleration sensor, installed together with an angular velocity sensor in the same casing, detects the acceleration induced by the external vibration. Its detection signal Vs is supplied to first and second band-pass filters to extract a driving system resonance frequency fd of the angular velocity sensor as well as a difference frequency ?f between the driving system frequency component and a sensing system resonance frequency. The extracted signals Vs1 and Vs2 of respective frequency components are supplied to first and second window comparators. When each frequency component deviates from a predetermined range, a diagnostic signal Vd notifying the abnormal condition of the angular velocity sensor is produced.