1. Fuel tank
The function of the oil tank is to store oil, dissipate heat, precipitate impurities and separate air bubbles in the oil. There are three types of fuel tanks: open, isolated and pressure. The hydraulic oil in the open type oil tank communicates with the atmosphere through an air filter, and the Liteng excavator adopts an open type oil tank.
Symbol of the fuel tank:
2. Oil filter
(1) The filtration accuracy of the oil filter refers to the diameter of the oil filter (or filter material) that can effectively filter out the largest particles, expressed in microns. For example, an oil filter with a filtration accuracy of 5um can pass the largest particles with a diameter of 5um.
(2) The role of the oil suction filter is mainly to protect the hydraulic pump and prevent large particles of pollutants from being sucked into the pump during oil suction. The pressure difference of the oil suction filter is limited by the suction characteristics of the hydraulic pump. The maximum pressure difference in use is generally not greater than 0.02MPa. If the pressure difference is too large, it is easy to cause the hydraulic pump to suck up and cause cavitation damage. Therefore, the oil suction filter generally uses a 100um low-precision filter element. The filter material is copper wire braided mesh.
(3) Oil return line filter: From the installation position, it is ideal to install an oil filter in the system return line. Before the system oil flows back to the oil tank, the oil filter filters out contaminants invading the system and generated in the system to provide clean oil for the hydraulic pump. The oil filter of the oil return circuit adopts high-precision filter element, and the filtering precision is 10um. The filter material is synthetic fiber.
(4) Pilot circuit oil filter: The filtering accuracy is 5um. The filter core material is synthetic fiber.
Excavator's return oil filter and suction oil filter are generally installed in the oil tank.
3. Accumulator
The role of the accumulator: to store the energy in the hydraulic system and release it again when needed. The Yuchai excavator uses an airbag type accumulator with an inflation pressure of 1.6MPa and is installed on the pilot oil circuit. Its functions are as follows:
(1) As an emergency power source, if the flame is turned off, the boom and bulldozer can be put down to ensure safety;
(2) Eliminate oil pump pulsation.
4. Seals
Seals commonly used materials are nitrile rubber, polytetrafluoroethylene and so on.
Type seal ring 0 type seal ring can be used for static seal, rotary motion seal and reciprocating motion seal. When it is used for dynamic seal and the working pressure is greater than 7MPa, the retaining ring must be configured. Compression rate and stretching amount of 0-type sealing ring: If the compression amount of 0-type ring is too small, it will cause leakage of 0-type ring after assembly. If the compression amount is too large, it will cause the compression amount to be too large and cause rubber stress to loosen. Chi, forming a leak in the sealing device. The general static seal compression rate is 25%, and the transport seal compression rate is 15%. Generally, the tensile amount is 1.04 times for static seal and 1.02 times for transport seal.
Retaining ring: Retaining ring and O-ring are used. Its function is to prevent the O-ring from being inserted into the gap between the sealing coupling parts due to elastic deformation after being subjected to pressure. If the 0-ring receives high pressure on one side, the retaining ring is installed on the low-pressure side of the 0-ring. If the 0-ring bears high pressure on both sides, the retaining ring is installed on both sides. The material of the retaining ring is Teflon.
0-ring installation groove width: 1.5 times the cross-sectional diameter of the 0-ring during static sealing, 1.3 times the cross-sectional diameter of the 0-ring during reciprocating sealing, and 1.1 times the cross-sectional diameter of the 0-ring during rotary sealing.
Example of 0-ring mark: The 0-ring with an inner diameter of 18 mm and a cross-sectional diameter of 1.8 mm is marked as 18x1.8.
Y-shaped cross-section is Y-shaped.
Installation of Y-shaped ring: a. When installing various types of Y-shaped sealing rings, the parts passed through, such as the cylinder and the end of the piston rod, should have a chamfer of 15-30 °; When the Y-ring is installed, grease or working oil should be applied on the surface of the sealing ring and the part where it passes through; c. When installing various types of Y-rings, the concave portion (lip end surface) of the Y-ring should be directly opposite Pressure medium; d. When installing various Y-shaped sealing rings, pay attention to the thorough cleaning of the sealing couple and hydraulic parts, and prevent the introduction of sand and iron debris and other debris.
