The one-way hydraulic system is for work tools that require one-way pressurized hydraulic flow. A hydraulic hammer is a good example.
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| Illustration 1 | g02160841 |
(1) Relief valve (2) Line (return from work tool) (3) Line (supply oil to work tool) (4) Main control valve (5) Proportional reducing valve (6) Line (7) Passage (pump delivery flow) (8) Passage (9) Attachment control valve (10) Passage (pump delivery flow) (11) Flow compensator valve (12) Load check valve (13) Passage (14) Hydraulic tank (15) Pilot pump (16) Line (pilot oil supply) (17) Front pump (18) Rear pump (19) Pilot manifold (20) Line (pilot oil flow) (21) Return line (22) Proportional reducing valve | |
Pilot pump (15) sends pilot system oil through line (16) to pilot manifold (19). The pilot system oil then flows through line (20) to proportional reducing valves (5) and (22) .
When the work tool control is operated, an electrical signal from the control is sent to the machine ECM. The machine ECM energizes proportional reducing valve (5).
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| Illustration 2 | g02160860 |
(4) Main control valve (9) Attachment valve | |
When proportional reducing valve (5) is energized, the spool in attachment control valve (9) shifts downward. The oil delivery from the main pumps flows from passage (11) through attachment control valve (9), load check valve (12), flow compensator valve (11), passage (10) and passage (13). The oil delivery from the main pumps in passage (13) now flows through line (3) to the work tool.
The return oil from the work tool flows through line (2), line (6) to return line (21). The return oil in line (21) now flows back to the hydraulic filters and the hydraulic tank (14) .
The pressure in the work tool is controlled by relief valve (1) .
Note: The pressure setting for the relief valves must be reset to the specification of the supplier for the work tool that is being used.