Cómo mantener el sistema hidráulico mecánico

The hydraulic transmission system has the advantages of small size, lightweight, large specific power, stable operation, and stepless speed regulation. It is widely used in various cranes. However, the transmission efficiency of the hydraulic transmission system is lower than that of other transmission systems, and it is easy to produce faults and it is difficult to analyze and eliminate the faults. Therefore, maintenance personnel is required to have certain basic knowledge of hydraulic systems. Leakage Classification: There are two main types of leakage in the hydraulic system of construction machinery: leakage at fixed seals and leakage at moving seals. Leaks at fixed seals mainly include cylinder bottom, The joints of various pipe joints, etc., the motion seals mainly include the piston rod of the oil cylinder, the valve stem of the multi-way valve, and so on. The oil leakage can also be divided into external leakage and internal leakage. External leakage mainly refers to the leakage of hydraulic oil from the system to the environment. Internal leakage refers to the existence of pressure difference between the high and low-pressure sides and the failure of the seal. Make the hydraulic oil flow from the high-pressure side to the low-pressure side inside the system.

Reasons affecting leakage:

1. ①Selection of seals The reliability of the hydraulic system depends to a large extent on the design of the hydraulic system seal and the selection of seals. Due to the unreasonable selection of the seal structure in the design, the selection is not in compliance with the specification, and the compatibility of hydraulic oil and sealing material, load conditions, ultimate pressure, working speed, and environmental temperature changes are not considered in the design. These all directly or indirectly cause hydraulic system leakage to various degrees. In addition, due to dust and impurities in the operating environment of construction machinery, suitable dust-proof seals should be selected in the design to prevent dust and other dirt from entering the system to damage the seal and contaminate the oil, resulting in leakage. ② Other design reasons. In the design, the geometric accuracy and roughness of the moving surface are not comprehensive enough, and the strength of the connection part is not checked in the design, which will cause leakage in the work of the machine.
2.  ① Manufacturing and assembly factors (1) Manufacturing factors: All hydraulic components and sealing parts have strict dimensional tolerances, surface treatments, surface finishes, and geometric tolerances. If it is out of tolerance in the manufacturing process, such as the piston radius of the cylinder, the depth or width of the seal groove, the size of the hole for the seal ring is out of tolerance or due to processing problems, it has burrs or depressions, and the chrome plating falls off. The parts will lose the sealing function due to deformation, scratches, crushing, or uncompacted. ② Assembly factors: The hydraulic components should be free from savage operations during assembly. Excessive force will cause the parts to deform, especially the cylinder block, sealing flange, etc. with copper rods, etc.; the parts should be carefully inspected before assembly. The parts should be dipped in a little hydraulic oil and gently pressed in. When cleaning, use diesel oil, especially rubber components such as seals, dust rings, O-rings, etc. If gasoline is used, it will be easy to age and lose its original elasticity, thereby losing the seal function.
3.  Oil pollution and component damage ① Gas pollution Under atmospheric pressure, hydraulic oil can dissolve about 10% of air, and under the high pressure of the hydraulic system, more air or gas will be dissolved in the oil. Air forms bubbles in the oil. If the hydraulic support changes rapidly between high and low pressure in a very short time during the working process, the bubbles will generate high temperatures on the high-pressure side and burst on the low-pressure side. If the hydraulic system components When there are pits and damage on the surface, the hydraulic oil will rush to the surface of the component at a high speed to accelerate surface wear and cause leakage. ② Particle pollution hydraulic cylinders are the main executive components of some construction machinery hydraulic systems. Because the piston rod is exposed and directly contacts the environment during the working process, although dust rings and seals are installed on the guide sleeve, it is inevitable to Dust and dirt are brought into the hydraulic system, which accelerates the scratches and wear of seals and piston rods, which cause leakage. Particle pollution is one of the fastest factors for hydraulic component damage. ③ Parts damage The seals are made of oil-resistant rubber and other materials. Due to long-term use, aging, cracks, and damage will cause system leakage. If the parts are damaged by collision during the working process, the sealing element will be scratched, causing leakage.