HOUSING-FILTER 6Y3860 - Caterpillar

Illustration 1 g03876520
Schematic of the implement pumps
(1) Pump supply oil (implement system)
(2) Left implement pump
(3) Right implement pump
(4) Swashplate
(5) Bias spring
(6) Actuator
(7) Control spool
(8) Solenoid
(9) Case drain oil
(10) Suction oil
(11) Pilot pump
(12) Hydraulic oil tank
Illustration 2 g03876549
Location of the implement pumps
(2) Right implement pumps
(3) Left implement pumps Note: During normal operation, each of the implement pumps operate in the manner that is described below.The implement pumps are variable displacement axial piston pumps that supply hydraulic oil to the main control valves. Each pump contains a swashplate that is driven by a single actuator (6). Actuator (6) is controlled by proportional solenoid (8). Solenoids (8) are controlled by a PWM driver from the implement ECM based on implement demand. The small end of actuator (6) is connected to pump supply oil (1) from the discharge of the pump. The small end of actuator (6) also has bias spring (5) that assists in upstroking the pump during low discharge pressure. The large end of actuator (6) is connected to modulated pilot pressure that is controlled by control spool (7). The pilot pressure that is used to control the large end of actuator (6) is externally supplied by pilot pump (11). Implement pump displacement is controlled by a proportional current from the implement ECM to solenoid (8).When a higher pump displacement is desired, the current that is supplied to solenoid (8) is increased. This action shifts control spool (7) upward. This action drains a portion of the pilot pressure that is acting against the large end of actuator (6). The oil drains from the pump to case drain (9) to hydraulic oil tank (12). Pump