Analysis of Failure cause of Seal in Hydraulic Cylinder

Sealing is the most basic and important device to ensure the normal operation of the hydraulic system. Most leaks in hydraulic and pneumatic systems are caused by seal failure. This issue brings you the main reasons and forms of seal ring failure in hydraulic cylinders, and proposes specific solutions. Only by accumulating experience in work and continuously summarizing and analyzing the problems that arise in use can seals be better applied.

First seal Failure cause

1. Sealing design leads to failure

Unsuitable material selection (hydrolysis, chemical resistance, temperature resistance, surface velocity, etc.)

Unreasonable structural design (pressure, low temperature, overload, etc., such as string leakage)

Gap recommendations and tolerance levels that are not applicable

Unreasonable product selection (single acting, double acting, pressure maintaining requirements, etc.)

2. Failure caused by sealing application

Excessive system pressure

Application temperature too high or too low (temperature resistance failure, aging)

Surface roughness, oil contamination

Instantaneous overload

Damage caused by installation error

Sealing Failure and Preventive Measures of Two Hydraulic Cylinders

Phenomenon (1): Mechanical damage

Reason:

1. There are scars on the mating surface

2. Containing metal impurities or other impurities

3. There are burrs at the chamfer of the mating surface during assembly

Preventive measures:

1. Thoroughly inspect and clean the parts before assembly, and no impurities are allowed to enter

2. Improve the system filtration device and replace the system media on time

3. Increase the chamfer of the mating surface and make it as smooth as possible, removing burrs and burrs

Phenomenon (2): Extrusion

Reason:

1. Excessive fit clearance design

2. The system pressure is too high

3. Insufficient stiffness of the support ring causes gaps

Preventive measures:

1. Reduce fit clearance

2. Add support ring

3. If the pressure is too high, an additional buffer seal can be added

3. Re select sealing material

4. Change the material or size of the support ring

Phenomenon (3): Damaged lip

Reason:

1. Back pressure damage

Preventive measures:

1. Add a pressure relief hole on the lip side of the piston head or switch to a combination type double acting seal