| 摘要 |
PURPOSE:To prevent the overheat of an engine when a vehicle ascends a mountain road for a long time. CONSTITUTION:A hydraulic transmission device is equipped with a cooling fan device 24 installed in a working oil feeding passage 18 and a power steering device 20 installed between the feeding passage and a working oil return passage 14. The cooling fan device is equipped with a hydraulic motor 38 for revolving the fan at the number of revolution corresponding to the differential pressure DELTAP between before and behind, passage 40 making a detour around the hydraulic motor, and a differential pressure control valve 42 which is installed in the passage and controls the differential pressure DELTAP. In the ascent on a mountain road, the differential pressure DELTAP is increasing-corrected in comparison with in the ordinary traveling and the necessary flow rate Qs of the power steering device. |
