IDLER GP-TRACK 3518928 - Caterpillar

Standby
Illustration 3 g00575506
Implement Pump Regulator Control ValveStandbyThe load sensing control spool and the constant horsepower control spool work together. The spools regulate the pump flow according to demand and the hydraulic horsepower requirements. The piston for the pump minimum angle servo and the piston for the maximum angle servo are connected to the swashplate. The regulated pump pressure oil moves the swashplate toward the minimum angle for decreased pump flow.The minimum angle stop screw prevents excessive destroking of the swashplate. The maximum angle stop screw adjusts the maximum angle of the swashplate.Note: Throughout the explanation of the pump controls, the power shift pressure will remain constant. Changes in power shift pressure will cause an upstroking or destroking of the pumps.When all the hydraulic controls are in NEUTRAL, low signal pressure is directed to the right end of the load sensing control spool. With low signal pressure on the right end of the load sensing control spool, the force of standby pressure moves the load sensing control spool to the right against the spring force.With the implement controls and travel controls in NEUTRAL, the hydraulic power control system sets the power shift pressure to a setting which is dependent on engine speed. With the low idle speed at 700 rpm or below 700 rpm, the power shift pressure will be 800 kPa (116 psi). With the high idle speed at 1860 rpm or above 1860 rpm, the power shift pressure will be 2450 kPa (355 psi). The Vital Information Management System (VIMS) energizes the warm-up solenoid valves that are located on the front control valve and on the rear control valve. Energizing the warm-up solenoid valves allows the implement piston pump standby oil to flow to the hydraulic tank.The power shift pressure moves the constant horsepower control spool to the left. When the constant horsepower control spool is moved to the left, the center land on the spool opens the passage to the piston of the minimum angle servo. The pump discharge pressure is regulated around the load sensing control spool and around the constant horsepower control spool to the piston of the minimum angle servo. The piston of the minimum angle servo moves the swashplate toward the minimum angle.Upstroke
Illustration 4 g00575507
Implement Pump Regulator Control ValveUpstrokingThe following three conditions can cause an increase in flow from the main pumps:
An increase in the load sensing signal pressure
An increase in the power shift pressure
A decrease in the pump discharge pressureThe load sensing pressure plus the spring force acts on the right end of the load sensing control spool. The pump discharge pressure acts on the left end of the load sensing control spool.When the load sensing signal pressure increases, the load sensing control spool moves to the left. Moving the load sensing control spool to the left opens the passage from the slow return check valve and orifice to the tank.When the pump is in balance, the constant horsepower control spool is positioned so that the passage to the slow return check valve