EDGE AS. 2642215 - Caterpillar

Illustration 1 g00810391
(1) Hydraulic oil cooler (2) Fan drive motor (3) Relief valve (4) Tank (5) Brake and fan drive pump (6) Priority valve (7) Check valve (8) Accumulator shuttle valve (9) Brake control valve (10) Line to the rear brake (11) Line to the front brake (12) Accumulator (13) Spool for the cut-in pressure and the cut-out pressure (14) Relief valve (15) Line to the secondary steering pump (16) Hydraulic tank breather (17) Line to the pump for the work tools and the steering pump (18) Line from the relief valve and from the manifold (19) Hydraulic oil filterThe brake and fan drive system is an open center hydraulic system. The brake and fan drive system contains a fixed displacement hydraulic pump. The brake system has priority over the fan drive system.When the engine is started, hydraulic oil is drawn from tank (4) by the brake and fan drive pump (5). Hydraulic oil flows from pump (5) to priority valve (6). The spring holds the spool for the cut-in pressure and the cut-out pressure (13) to the right. The relief valve (14) is closed. Spool (13) and relief valve (14) move. The priority valve directs hydraulic oil to check valve (7). As the hydraulic oil pressure increases, the check valve opens and the hydraulic oil flows to the accumulator shuttle valve (8) .The accumulator shuttle valve (8) directs hydraulic oil to the accumulator with the lowest pressure first. As the hydraulic oil pressure to the first accumulator increases, the accumulator shuttle valve moves. This allows both accumulators to charge at equal pressures. Hydraulic oil also flows to the spool for the cut-in pressure and the cut-out pressure (13) and oil flows to the