CDM816D WHEEL LOADER
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Fig. 3-7 Schematic Diagram of Implement Hydraulic System
(i) Working principle
The engine operation is realized by driving the gear via torque converter. When two control levers are
at neutral positions, the tilt valve stem and the boom valve stem of the multi-way valvewill be also at
the neutral positions. The oil from the gear pump returns to the oil tank through the multi-way valve.
There are three control positions (i.e. “Tilt Down”, “Neutral”, “Tilt Up”) for the tilt control level to control
the movement of the bucket.
When the engine is running, the tilt control lever is pushed forward, at this time, the tilt valve stem
moves forward, the pressure oil from the main oil circuit flows into the small chamber of the tilt cylinder
through first part of the multi-way valve to push the cylinder piston backward, thus realizing the
tilt-down of the bucket.
When pulling back the control lever, the tilt valve stem moves backward, and the pressure oil from the
main oil circuit flows into the large chamber of the tilt cylinder through first part of the multi-way valve to
push the cylinder piston forward, thus realizing bucket retraction.
When the valve stem is at neutral position, the tilt valve stem is kept at the neutral position under the
action of the return spring. Meanwhile, the tilt oil chamber is in locking state.
There are four control positions (i.e. “Lift”, “Neutral”, “Lower” and “Float”) for the boom cylinder control
lever to control the lifting of boom.
When pushing the control lever forward, the boom valve stem moves forward and the pressure oil from
the main oil circuit flows into the small chamber of the lifting cylinder through second part of the
multi-way valve to push the cylinder piston move down, so as to realize lowering. Meanwhile, the oil in
the large chamber of the lifting cylinder returns to the oil tank through the multi-way valve.
When pulling back the control lever, the boom valve stem moves backward and the pressure oil from
the main oil circuit flows into the large chamber of the lifting cylinder through second part of the
Oil from priority valve EF port
