Hydraulic Hose Assembly Common Problems and Reasons

The hose assembly is composed of wire braided or wound hose, connector core, sleeve and connecting nut. Hose assemblies must be securely connected and securely sealed. The connection effect and sealing perಌformance of the hydraulic hose assembly depend on the friction between the pipe joint and the hose and the friction of the pipe joint shape. Among them, rubber friction depends on the amount of clamping, shape friction depends on the shape of the clamping part, hydraulic hose common problems and their reasons are as follows:

[1] Oil leakage in the clamping part

The main reason for the൩ leakage of oil in the clamping part of the hose is 🍎the poor sealing of the clamping part. There are two reasons for affecting the sealing quality of the clamping part:

First, due to the mismatch between the size of the hole in the hose and the connector core or the thickness deviation of the flexible pipe wall, the fastening for♍ce of the connector core or sleeve on the hose is insufficient when the pressure is pressed, resulting in oil leakage in the part with a small amount of pressure.

Second, because the material hardness of the clamping core and the clamping sleeve is too high,♛ the steel wire of the steel wire reinforcement layer may be 🍒broken, resulting in oil leakage or even joint withdrawal of the hose assembly at the steel wire fracture.

[2] Pipe body blasting

The burst of t🤪he pipe body can be divided into two forms according to the different burst locations:

First, the position of the crack is at both ends of the hose and within 25mm from the pressure sleeve. According to GB/T5563-2013 hydrostatic test method for rubber and plastic hoses and hose assemblies, 8.4.3 Basis for damage Leakage at the pipe joint, pulling out of the pipe head or cracking of the hose near the pipe joint are considered to be quality problems of the assembly itself. Does not necessarily indicate that the hose d📖oes not meet the requirements.

Second, the position of t🤪he crack is🌊 25mm away from the buckle jacket. Related to hose selection, working pressure and pulse frequency, installation conditions and working temperature:

1 Hose selection

According to the medium conveyed by the hydraulic system and the flow rate of the medium, select the appropriate hose specifications and types. The i꧂nner rubber layer of the hose is in direct contact with the hydrauli🌠c medium, and the hose type is reasonably selected according to the principle of similarity compatibility. The inner diameter of the hose matches the medium flow of the hydraulic system, and the pipe diameter is too small, which speeds up the flow rate of the hydraulic system medium, resulting in the temperature rise of the system medium and the increase of the pressure drop, affecting the system performance.

2 Working pressure and pulse frequency

The working pressure applied🐼 by the hydraulic system to the hose assembly should not exceed the maximum working press🌜ure of the hose. When the hose assembly is used frequently, the service life of the hose will be significantly reduced.

The hose assembly maintains a high frequency pulse under the working state, and there is a cumulative broken wire on the hose wire. When the broken wire accumulates to a certain extent, the hose wil🐭l burst in the position of many broken wires. In the case of high pulse frequency, it is recommended to shorten the replacement cycle of the hose assemb﷽ly.

3 Installation conditions and working temperature

When the hose assembly is installed, the hose structure will be deformed, which will change the wire arrangement of the hose layer and cause the pipe body to burst. There should be no twis🔯ting, stretching, 🔥rolling, chemical corrosion, physical wear, installation less than the minimum bending radius, etc. Install the hose assembly away from the heat source, if necessary, install a protective sleeve or isolate the heat source, and the hose should be used within the range permitted by the operating temperature.

4 Quality of hose

① Oil leakage from trachoma of pipe body

The phenomenon of oil leakage in the sand hole of the pipe body is generally manifested as oil leakage or linear injection after the rubber bubbling outside the hose. The oil l𝓀eakage from the sand hole of the pipe is mostly caused by the quality problems of the hose, such as the impurities in the glue of the pipe body, the local damage of the pipe body and the defects in the mold release of the pipe body.

② The outer covering is cracked

Construction machinery in outdoor construction, due to withstand the sun and rain, the outer rubber layer of the hose is constantly aging and deteriorating. When the hose is installed less than the꧑ minimum bending radius, the rubber covering of the hose will crack. When the rubber cracks reach the steel wire layer, the steel wire loses protection, th🤪e steel wire strength decreases and the hose bursts.

③ The lining is cracked

The cꦑracks in the hose layer are generally caused by the hardening of the inner rubber layer, and the direct cause is the rubber failure of the lining layer. The reasons are as follows: first, the use environment of the hose assembly or the temperature of the hydraulic medium is too high, resulting in the aging of the rubber of the lining layer and the loss of elasticity and brittle rupture of the oil leakage; The second is the use of environmental or hydraulic medium temperature is too low, the rubber appears low temperature brittleness (glass), when the hose assembly is under pressure to produce movement and rubber rupture caused by oil leakage.