SHAFT AS 8G4659 - Caterpillar

One-Way / One or Two Pump with electronic control is designed to allow complete electronic control over the work tool. This hydraulic system allows the operator to control a work tool with a one-way flow system with from one pump or two pumps.Hammer Return Filter
Illustration 2 g02422341
One-Way / One or Two Pump - Electronic Control with Hammer Return Filter
(2) Attachment control valve
(3) Hydraulic oil cooler
(4) Tool relief valve
(5) Attachment control valve
(13) Pilot pump
(14) Drive pump
(15) Idler pump
(22) Proportional reducing valve (A2 extend)
(23) Proportional reducing valve (A1 extend)
(26) Hydraulic tank
(27) Hammer return filter
(28) Accumulator One-Way / One or Two Pump - Electronic Control with Hammer Return Filter allows the return oil from the work tool to return directly through a filter before returning to the hydraulic tank. Hammer return filter (27) removes moisture and contaminates from the oil. This system is commonly used with hammers.Accumulator (28) is located between the filter and oil cooler (3) to provide back pressure to the return systemOne-Way Flow from One Pump
One-way flow from one pump can be achieved by selecting a work tool that requires one-way flow from one pump. The work tool can be selected through the monitor or by the work tool select switch. A typical example is a hammer that receives oil from one pump only.When one pump flow is required to the work tool, the pump supplying the oil can be programmed through the monitor. The following situations are listed to increase controllability of the work tool.
When the work tool with a boom and bucket operation is used most often, the idler pump is recommended as the supply pump.
When the work tool with a stick and swing operation is used most often, the drive pump is recommended as the supply pump.Reference: Refer to Testing and Adjusting, "Work Tool Parameter - Program" for the tool control system to change the settings for work tool operation.Reference: Refer to Testing and Adjusting, "One-Way / One or Two Pumps - Electric Control: Default Value of Work Tool Parameters" for the Tool Control System to reference the factory settings.
Table 1
Operation Lever List
Control Extension
Right joystick thumb wheel Push Forward
Electric foot pedal Push Forward
Electric foot switch Push ON
Illustration 3 g02429296
One-Way Flow from One Pump (idler pump)
(1) Tool line relief valves
(2) Attachment control valve
(3) Hydraulic oil cooler
(4) Tool relief valve
(5) Attachment control valve
(9) Proportional reducing valve (Flow limit 2)
(10) Proportional reducing valve (Flow limit 1)
(13) Pilot pump
(14) Drive pump
(15) Idler pump
(23) Proportional reducing valve (A1 extend) The following description is made under the assumption that the drive pump is supplying oil to the work tool.When the device for activation listed in Table 1 is pressed, the machine ECM sends a modulated signal to proportional reducing valve (23). Proportional reducing valve (23) allows pilot oil to flow to attachment control valve (5). Attachment control valve (5) shifts, allowing high-pressure oil from the drive pump to flow to the work tool.When abnormally high pressure occurs in the line to the work tool, tool relief valve (4) opens at a set pressure.