Abstract: A gas sensor (1) including a sensor element (10); a metallic shell (138); a tubular outer surface member (190) attached directly or indirectly to the metallic shell, constitutes an outer surface of the gas sensor, and extends toward a rear end side in relation to the metallic shell; and a tubular protection member (210, 220) which is detachably fixed to a fixation region C1, C2 of an outer circumference of the outer surface member. The protection member includes a first arc portion (212), a second arc portion (222), and a fixation portion (214,224) brought into contact with and is fixed to the fixation region. When the protection member fixed to the outer circumference of the outer surface member by fixing the fixation portion to the fixation region is viewed in the axial O direction, the first arc portion and the second arc portion cover in total at least 90% of the entire circumference of the outer surface of the outer surface member.

Abstract: An automatic door system includes a motor which drives a door to open and close. A CPU operating in accordance with a signal from an encoder operatively coupled to the motor detects the position of the door and prepares and applies a control signal based on the detected door position to a motor drive unit. The motor drive unit alternately drives and brakes the motor. The CPU calculates the speed of the door at a particular door position on the basis of the signal from the encoder and operates to make the door speed equal to the aimed speed for the current door position.