The hydraulic cylinder of Hitachi excavator shall be tested after installation. The test items are as follows.
(1) Motion balance inspection
Run for 5 ~ 10 times under the minimum pressure force 1, and check whether the piston movement is stable, flexible and free of blocking. The minimum pressure is related to the type of seal. recommend:. Do not take about 0.3MPa for v-clip, y-clip and v-clip fabric sealing ring, about 0.5MPa for v-clip fabric sealing ring PI, and 0.15mpao for piston ring
(2) Load test
Add the maximum working load to the piston rod, and the pressure force in the cylinder is the maximum working pressure. Under the action of force, operate the full stroke reciprocating motion for 5 times. At this time, the cylinder piston rod moves stably and flexibly, and all parts of the cylinder have no permanent deformation and other abnormalities.
(3) External leakage test of hydraulic cylinder
Under the action of force 2 (= 1.5 force), the reciprocating motion of the piston is about 5 ~ 10 min, and there shall be no oil leakage at all seals and welds.
(4) Internal leakage test of hydraulic cylinder
Add a certain static load f (F = PA, a is the effective working area of the piston) to the piston rod, and the moving distance of the piston shall not exceed the rated value within lmin.
(5) Strength test of hydraulic cylinder
Apply test pressure force 3 (force 3 = (1.5-1.75) P) from both ends of the cylinder for 2min, and all parts shall not be damaged or permanently deformed.
(6) Retighten after test
After the above tests, looseness of cylinder fastening may occur. Therefore, for the sake of caution, the pull rod and gland bolt shall be tightened again after the test. If it is used directly after the pressure test, the bolts may be damaged one by one due to the uneven load on each bolt, resulting in serious failure.
After the above work is completed, a regular inspection system shall be established to prevent or reduce accidents.
