POSITION DETECTOR AND INDUSTRIAL VEHICLE HAVING POSITION DETECTOR

摘要

PROBLEM TO BE SOLVED: To provide a position detector capable of accurately detecting the position of a moving body in a fluid pressure cylinder. SOLUTION: In a position detector PD for detecting the position of a piston rod 6 in accordance with the passage of time from the transmission of a ultrasonic wave by a ultrasonic sensor 11 to the lower end face of a piston rod 6 reciprocatingly moved linearly with the supply/discharge of a hydraulic oil to/from a fluid pressure cylinder 5 to the reception of the ultrasonic wave reflected on the lower end face of the piston rod 6 by the ultrasonic sensor 11 a microcomputer 17 is responsive to the temperature of the hydraulic oil for setting the intensity of the ultrasonic wave transmitted by the ultrasonic sensor 11 when the temperature of the hydraulic oil is detected by a temperature sensor 18, providing for transmission of the ultrasonic wave having intensity adaptable to the temperature of the hydraulic oil and accurate detection of the position of a moving body in the fluid pressure cylinder 5 even when the viscosity of the hydraulic oil is changed with the temperature change of the hydraulic oil.