| 摘要 |
PURPOSE: To prevent the temperature of operating oil from being lowered when the environmental temperature drops, by providing a heat exchanging thin pipe for exchanging heat with operating oil near a driving piping, etc., and forcibly feeding the operating oil discharged from an oil pressure pump to the heat exchanging thin pipe through another thin pipe. CONSTITUTION: If the oil temperature (t) of operating oil 25, detected by a temperature sensor 31 is the lower limit value tL or less when a hydraulic elevator is in the waiting state of call waiting, an oil pressure pump 12 is operated, and the operating oil 25 is made to circulate by a closed circuit for returning the total amount of oil to a tank 10 through a flow control valve 14 and a piping 17. Thereby, the temperature of the operating oil is raised by viscosity of the operating oil or frictional heat between operating oil and a piping. A solenoid switching valve 22 is opened in t>tL, and the operating oil is partially allowed to flow to a heat exchanging thin pipe 19 by the flow control vale 14 through a thin pipe 18. Thereby, the temperatures of operating oil 26, 27 in a driving piping 15 and a cylinder 3, are raised by heat exchange. |
