CRANKSHAFT 1M9194 - Caterpillar

The oil from the closed loop enters through passage (1). The oil flows into the chamber of spring (6). The oil then continues into the chamber of spring (4). Makeup valve (3) is closed by spring (4) and by the pressure of the oil in the spring cavity. The pressure of the oil acts against relief valve (5). The force of spring (6) keeps relief valve (5) closed until oil pressure in the loop line reaches relief pressure. When the oil pressure in the loop line becomes greater than the force of spring (6), relief valve (5) opens. The pressure of the oil on relief valve (5) is larger than the force of spring (6) and the small area of relief valve (5) on the spring side. Oil flows around relief valve (5) from the high pressure loop through passage (2) into the charge loop.Whenever one of the crossover relief valves open, some of the oil is vented over the charge relief valve and some of the oil is vented over the makeup valve back into the loop.Charge Pump
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Charge PumpThe charge pumps (6) fill the system with oil during start-up. The pumps provide oil for the implement pilot circuit and the pumps provide oil in order to compensate for the internal leakage inside the closed circuit system. The charge pump (6) is a crescent type gear pump. The charge pump (6) is a component of the implement pump that is mounted on the rear of the implement pump.The charge pump oil goes through the oil filter. If there is a pressure drop across the oil filter due to cold oil, the cold oil relief valve (8) will open. The cold oil relief valve (8) will recirculate some of the discharge oil to the charge pump (6) in order to prevent the charge pump from cavitating.Pump Control Valve
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Pump Control Valve (1) Spring (2) Spool (3) Lever (4) Spring (5) Lever (6) Pin (7) Spring (8) Passage for charge oil (9) Passage for control piston (10) Feedback lever (11) Passage to control piston (12) Passage for charge oilThe oil from the pilot valve is directed to either the right end or the left end of spool (2). The pressure shifts the spool and the spool sends the charge pressure oil to the control piston. As the spool shifts, pin (6) moves either lever (3) or lever (5). The pin compresses spring (4). The spring resists the movement of spool (2) .Charge pump oil is sent to the control piston. As the control piston is moved to upstroke the pump, feedback lever (10) is also moved. Feedback lever (10) moves either lever (3) or lever (5). The lever that is moved is the opposite of the lever that is moved by spool (2). Spring (4) compresses further. The force of spring (4) pulls the lever that was moved by spool (2), back toward the NEUTRAL position. Also, the spring moves spool (2) toward the NEUTRAL position. When the spool