| 摘要 |
PURPOSE:To prevent a power loss as well as a waste of fuel of each part of an engine by connecting a loose coupler and a single-acting type oil pressure cylinder and providing a switching valve to connect a center bypass oil passage at a low pressure side and the single-acting type oil pressure cylinder. CONSTITUTION:Variable capacity type pumps 1 and 2 are driven in a same speed by an all-speed governor 3 with a Diesel engine 4 for a construction machinery. Back pressure generating valves 10 and 18 are connected between center bypass. passages 9 & 17, and a tank T. When direction switching valves 6, 7, 14 and 15 of both valve blocks 12 and 20 are returned to the medium positions at a time of rated rotation stage of an engine, an oil pressure cylinder 33 is extended by the back pressure generated at the center bypass oil passages 9 & 17, and a speed control lever 23 is returned to an idling position by an elastic force of a governor spring 26. This construction permits to lower the rotating number of the engine as well as to save driving energy of the pumps. |
