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Loader is mainly used to shovel soil, sand, lime, coal and other bulk materials, but also for the ore, hard soil, such as mild shovel digging operations. The following is to introduce the loading arm can not lift the reasons.

A. hydraulic pump serious wear. In the low-speed operation of the pump leakage is serious; high speed operation, the pump pressure slightly increased, but because of the pump wear and internal discharge, volumetric efficiency decreased significantly, it is difficult to achieve the rated pressure. The hydraulic pump for working for a long time and wear, the temperature, the resulting wear of hydraulic components and seals of aging, damage, loss of sealing capacity, hydraulic oil deterioration, resulting in failure.

B. hydraulic components selection is not reasonable. The specification of the arm cylinder is 70 / 40 non-standard series, and the sealing parts are also non-standard parts. Boom cylinder bore small, is bound to make the adjustment for high pressure system.

C. hydraulic system design is not reasonable. As can be seen from Figure 1, the control valve and the hydraulic steering gear for a single pump in series, the safety valve set pressure 16MPa, and the rated operating pressure of the hydraulic pump is also 16MPa. The hydraulic pump is often at full load or overload for a long time (high pressure) case, and system hydraulic impact, long-term oil, hydraulic oil pollution, increased pump wear, so pump pump shell burst (after he was found such failure).