SECTION 6 WORK EQUIPMENT GROUP 1 STRUCTURE AND FUNCTION GROUP 1 STRUCTURE AND FUNCTION 1. HYDRAULIC SYSTEM OUTLINE 1. HYDRAULIC SYSTEM OUTLINE The loader hydraulic system is a pilot operated, closed center system which is supplied with flow from the variable displacement piston main hydraulic pump. The loader system components are : В Main pump В Main control valve В Bucket cylinder В Boom cylinders В Remote control valve (Pilot control valve) В Safety valve The main control valve is load pressure independent flow distribution system which routes flow to the boom, bucket or auxiliary cylinders (not shown) when the respective spools are shifted.
Flow from the main pump is routed to the main control valve where pump outlet pressure is reduced to pilot circuit pressure. The main control valve flow to the remote control valve. The remote control valve routed flow to either end of each spool valve section in the main control valve to control spool stroke. A accumulator mounted on safety valve supplies a secondary pressure source to operated remote control valve so the boom can be lowered if the engine is off. The return circuit for the main hydraulic system have return filter inside the hydraulic tank. The return filter uses a filter element and a bypass valve. The bypass valve is located in the upside of filter. 6-1