336F and 340F Excavators Tool Control System Caterpillar

Illustration 1	g03550959
Combined Function - Electronic Control (1) Stick cylinder (2) Boom cylinders (3) Tool pressure relief (6) Left joystick (stick) (7) Right joystick (boom) (8) Main control valve (11) Proportional reducing valve (A2 extend) (12) Proportional reducing valve (A1 extend) (13) Boom DOWN control pressure sensor (14) Boom UP control pressure sensor (15) Stick OUT control pressure sensor (16) Stick IN control pressure sensor (17) F2.2 stack valve (18) Tool line relief valve (19) Attachment control valve (drive pump) (20) Attachment control valve (idler pump) (21) Tool line relief valve (22) Hydraulic oil cooler (23) Pilot manifold (28) Pump control solenoid (29) Pump control solenoid (30) Stick 2 control valve (31) Stick 1 control valve (32) Boom 1 control valve (33) Boom 2 control valve (34) Main relief valve (35) Hydraulic tank (36) Pilot relief valve (37) Pilot pump (38) Drive pump (39) Idler pump

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.

Direct Return (If Equipped)

Illustration 2	g03551861
One-Way / One or Two Pump - Electronic Control with Direct Return (8) Main control valve (22) Hydraulic oil cooler (35) Hydraulic tank (41) Return line

One-Way / One or Two Pump - Electronic Control with Direct Return System allows the return oil from the work tool to return directly to the hydraulic tank in one-way flow mode. This system is commonly used with hammers.

The direct return system allows for a high flow of oil through the work tool by bypassing the return check valves and oil cooler that will cause resistance in the return system.

One-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.

Illustration 3	g03551902
Combined Function - Electronic Control (3) Tool pressure relief (8) Main control valve (11) Proportional reducing valve (A2 extend) (17) F2.2 stack valve (18) Tool line relief valve (19) Attachment control valve (drive pump) (20) Attachment control valve (idler pump) (21) Tool line relief valve (23) Pilot manifold (28) Pump control solenoid (29) Pump control solenoid (34) Main relief valve (35) Hydraulic tank (37) Pilot pump (38) Drive pump (39) Idler pump

The following description is made under the assumption that the idler 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 (11). Proportional reducing valve (11) allows pilot oil to flow to attachment control valve (20). Attachment control valve (20) shifts, allowing high-pressure oil from the idler pump to flow to the work tool.

When abnormally high pressure occurs in the line to the work tool, tool relief valve (3) opens at a set pressure. This opening will allow the high-pressure oil into the return system and back to the hydraulic tank.

Oil returning from the work tool flows through the oil cooler and back to the hydraulic tank.

During the operation of the work tool, the oil flow for the idler pump is controlled by pump control solenoid (29) and the machine ECM. Since attachment control valve (19) does not shift, the drive pump is controlled by pump control solenoid (28) and the machine ECM.

One-Way Flow from Two Pumps

One-way flow from two pumps can be achieved by selecting a work tool that requires one-way flow from two pumps. 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 two pumps.

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.

Illustration 4	g03552364
Combined Function - Electronic Control (3) Tool pressure relief (8) Main control valve (11) Proportional reducing valve (A2 extend) (12) Proportional reducing valve (A1 extend) (17) F2.2 stack valve (18) Tool line relief valve (19) Attachment control valve (drive pump) (20) Attachment control valve (idler pump) (21) Tool line relief valve (23) Pilot manifold (28) Pump control solenoid (29) Pump control solenoid (34) Main relief valve (35) Hydraulic tank (37) Pilot pump (38) Drive pump (39) Idler pump

When the device for activation listed in Table 2 is pressed, proportional reducing valve (11) and proportional reducing valve (12) receives a modulated signal from the machine ECM. Proportional reducing valve (11) allows pilot oil to flow to attachment control valve (20). Proportional reducing valve (12) allows pilot oil to flow to attachment control valve (19). This shifts attachment control valve (19) and attachment control valve (20), allowing high-pressure oil from the drive pump and the idler pump to combine and flow to the work tool.

When abnormally high pressure occurs in the line to the work tool, tool relief valve (3) opens at a set pressure. This opening will allow the high-pressure oil into the return system and back to the hydraulic tank.

Oil returning from the work tool flows through the oil cooler and back to the hydraulic tank.

During this operation of the work tool, the oil flow for the idler, drive pumps are controlled by pump control solenoids (28) and (29) and the machine ECM.