7-13
DIG FUNCTION DRIFT CHECK
Measure dig function drift, which can be
caused by oil leakage in the control valve
and boom, standard arm, and standard
bucket cylinders, with the loaded bucket.
When testing the dig function drift just
after cylinder replacement, slowly operate
each cylinder to its stroke end to purge air.
Preparation
Load bucket fully. Instead of loading the
bucket, weight(W) of the following
specification can be used.
W=M
3
Ý
1.5
Where :
M
3
= Bucket heaped capacity (m
3
)
1.5= Soil specific gravity
Position the arm cylinder with the rod 20
to 30 mm extended from the fully retracted
position.
Position the bucket cylinder with the rod
20 to 30 mm retracted from the fully
extended position.
With the arm rolled out and bucket rolled
in, hold the bucket so that the height of
the bucket pin is the same as the boom
foot pin.
Keep the hydraulic oil temperature at
50
佳
5˚C.
Measurement
Stop the engine.
Five minutes after the engine has been
stopped, measure the changes in the
positions of the boom, arm and bucket
cylinders.
Repeat step
Θ
three times and calculate
the average values.
10)
(1)
(2)
刮
余
刯
到
刱
刲
(3)
刮
刯
到
The measured drift should be within the following specifications.
Unit : mm / 5min
(4)
300L7MS08
Model
Drift to be measured
Standard
Maximum allowable
Remarks
HX430 L
Boom cylinder
10 below
15
Arm cylinder
10 below
15
Bucket cylinder
40 below
50
