Hydraulic Cylinder

The hydraulic cylinder is the core actuator in the hydraulic system, which is mainly used to convert hydraulic energy into mechanical energy and push the load to complete linear reciprocating motion. Hydraulic cylinders are widely used in engineering machinery, mining equipment, metallurgy, ships, aerospace and other fields.

Main Components
Cylinder body: The outer shell of the cylinder, usually made of steel, bears internal and external pressures and protects internal components.
Piston: Located inside the cylinder, the piston rod is driven by the pressure of the hydraulic oil to make linear reciprocating motion and generate mechanical output.
Piston rod: Connected to the piston, extends out of the cylinder to transmit motion to the workload.
Sealing ring: Used to seal the inside and outside of the cylinder to prevent hydraulic oil leakage and maintain system pressure.
End cover: Closes both ends of the cylinder, fixes the piston rod and piston, and provides an interface for the entry and exit of hydraulic oil.
Buffer device: Used to alleviate the impact of the piston end movement and protect the internal structure of the cylinder.

Working Principle
The hydraulic cylinder enters different cavities at both ends of the cylinder through high-pressure hydraulic oil to control the reciprocating motion of the piston in the cylinder. When the hydraulic oil enters from one end of the cylinder, the piston pushes to the other end to generate mechanical output; conversely, when the oil flows in from the other end, the piston moves in the opposite direction to complete the force output in different directions.

Product Features
High efficiency: The hydraulic cylinder can achieve a large force output and is suitable for high-load operations.
Accurate control: Accurate motion control can be achieved through the flow and pressure regulation of the hydraulic oil.
Long service life: Good design and materials make the hydraulic cylinder have a long service life.
Easy maintenance: Regular inspection and replacement of accessories such as seals can ensure its long-term stable operation.

Application Areas
Construction machinery: such as excavators, cranes, etc., used to control the movement of components such as buckets and booms.
Mining equipment: used to promote various actions of mining machinery, such as drilling rigs, bulldozers, etc.
Metallurgical equipment: such as presses, hydraulic shears, etc., used to control the movement of mechanical parts.
Automotive industry: The power source in the hydraulic system drives the movement of wheels, suspensions and other components.

Common Problems
1. Oil leakage in the cylinder
Oil leakage is one of the common faults of hydraulic cylinders, which usually occurs when the seal is damaged, worn or improperly installed.
Causes:
Aging or damage of the seal: Long-term high-pressure operation or oil contamination causes the seal to age, harden or crack, and cannot effectively seal the cylinder.
Pollution inside and outside the cylinder: Dust and impurities enter the sealing area of the cylinder, causing the seal to wear or damage.
Improper installation: Improper installation of the seal, rough surfaces inside and outside the cylinder, and inappropriate matching tolerances can all cause oil leakage.
Solution:
Check and replace the seal regularly to avoid long-term use of aging seals.
Ensure the cleanliness of the hydraulic oil and replace the oil regularly.
When installing the seal, make sure it is placed correctly to avoid damage.
2. Cylinder stuck or inflexible
The cylinder is inflexible or stuck, usually due to excessive friction of internal components or insufficient hydraulic oil.
Causes:
Excessive internal friction: The inner wall of the cylinder or the surface of the piston is worn, or foreign matter enters the cylinder, causing the piston movement to be blocked.
Oil contamination: Impurities in the oil cause the piston and seal in the cylinder to wear too quickly.
Insufficient oil or too high viscosity: The quality of the hydraulic oil is unqualified, or the amount of oil is too small, causing the cylinder to fail to work properly.
Solution:
Regularly check the inner wall of the cylinder and the surface of the piston to ensure that they are smooth and wear-free.
Keep the oil clean, replace the hydraulic oil when necessary, and check whether the viscosity of the oil is suitable for the working environment.
Check the working pressure of the cylinder to ensure that the system pressure is within the normal range.
3. Uneven cylinder movement
When the cylinder is working, the uneven movement may be caused by imbalance in the hydraulic system.
Cause:
Uneven pressure: The pressure of the two chambers of the hydraulic cylinder is unbalanced, causing the piston to fail to move evenly.
System leakage: A part of the system leaks, causing oil loss and unstable oil supply.
Gas enters the system: There is air or bubbles in the hydraulic oil, which causes the compressibility of the oil to change, affecting the uniformity of the cylinder movement.
Solution:
Check the pressure control valve in the hydraulic system to ensure that the pressure of each chamber is balanced.
Regularly check the hydraulic system for leaks and repair them in time.
Remove air or bubbles from the hydraulic oil to ensure that the oil is not contaminated.
4. The cylinder vibrates or impacts
During the operation of the cylinder, abnormal vibration or impact is usually caused by unstable pressure or poor buffering in the hydraulic system.
Causes:
Pressure fluctuation: The pressure fluctuation in the system is large, causing the cylinder to vibrate or impact during operation.
Buffer device failure: The buffer device of the cylinder fails and cannot effectively absorb the impact force at the end of the piston.
Air or moisture in the system: There are bubbles or moisture in the hydraulic oil, which causes the compressibility of the oil to change, resulting in uneven flow and vibration.
Solution:
Check and adjust the pressure control valve to maintain a stable pressure in the hydraulic system.
Check the buffer device of the cylinder and repair or replace it if necessary.
Replace the hydraulic oil to ensure that there are no bubbles or moisture in the oil.
5. The cylinder does not return or is stuck
If the cylinder cannot return or is completely stuck, it is usually because there is a fault in the hydraulic system or the cylinder is damaged.
Cause:
Insufficient hydraulic oil pressure: The oil pump pressure is too low to provide enough power to push the cylinder to move.
Valve failure: The hydraulic valve is stuck or damaged, causing the cylinder to be unable to normally enter or return oil.
Internal damage to the cylinder: The piston or piston rod in the cylinder is deformed and worn, causing the cylinder to be unable to move normally.
Solution:
Check the oil pump and pressure regulating device of the hydraulic system to ensure that the oil pressure is normal.
Check the hydraulic valve to ensure that the valve is not stuck and can work normally.
If the cylinder is damaged internally, it needs to be disassembled for repair or the damaged parts need to be replaced.