| 摘要 |
PURPOSE:To enable to control hydraulic pressure such that hydraulic apparatus can be operated smoothly under any temperature conditions, by controlling the driving voltage of a motor for driving a hydraulic pump in two stages according to the engine temperature detected by a temperature sensor. CONSTITUTION:If arrangement is such that the engine temperature is detected by a temperature sensor 8 and a contact piece 8a of the sensor 8 is brought into contact with a contact point (a) when an engine is sufficiently warmed up, a motor 1 is driven via a resistor R and drives a hydraulic pump to produce an optimum level of hydraulic pressure at the time when the engine is warmed up. On the other hand, if arrangement is such that the contact piece 8a of the sensor 8 is brought into contact with a contact point (b) when the engine temperature is low, the motor 1 is connected directly to a power source and increases the output torque so as to increase the hydraulic pressure by driving the hydraulic pump by a higher torque than that at the time when the engine temperature is high. This results in compensating adverse effect in operating hydraulic apparatus due to change in the viscosity of oil and O-RING at the time when the engine temperature is low by increasing the hydraulic pressure, so that the same feeling as at the time when the engine is warmed up can be obtained in operating hydraulic apparatus. |
