During the use of hydraulic hoist (hydraulic crane or hydraulic lift), some common problems may be encountered. The following is a detailed explanation of these problems:

1、 Insufficient pressure or decreased system performance

Hydraulic pump failure: After long-term use, the internal components of the hydraulic pump wear out, resulting in a decrease in volumetric efficiency and insufficient system pressure. Disassemble the hydraulic pump, inspect the gears, blades, and other parts, and replace those with severe wear.

Overflow valve malfunction: The overflow valve is stuck or the set pressure is inaccurate, which can cause abnormal system pressure. The overflow valve needs to be cleaned to remove internal impurities and readjust the set pressure.

Fault in directional valve: The valve core is stuck or the electromagnet is malfunctioning, which can affect the flow direction and flow rate of hydraulic oil. The stuck valve core can be cleaned and repaired by appropriate grinding; If the electromagnet is damaged, it needs to be replaced.

Hydraulic cylinder failure: Leakage inside the cylinder can cause insufficient thrust and weak movement. Check the piston seal and replace it promptly if it is damaged.

Balance valve failure: Blockage of the damping hole or stuck valve core of the balance valve can affect the balance performance of the system. The balance valve needs to be cleaned and inspected to ensure smooth damping holes and flexible valve core movement.

Air in the system: Air entering the hydraulic system can cause unstable system performance. It is necessary to open the exhaust valve and make each mechanism move back and forth multiple times to exhaust the air.

2、 Hydraulic oil leakage

Internal leakage:

The static seal O-ring between the piston rod and the piston is damaged or aged, resulting in internal leakage. O-ring needs to be replaced in a timely manner.

The failure of the dynamic seal between the piston and the cylinder wall can also lead to internal leakage. A new piston with a slightly larger outer diameter than the original size needs to be replaced to fully utilize the elasticity of the U-shaped sealing ring and achieve the initial sealing effect.

External leakage:

Damage or aging of the O-ring at the junction of the cylinder block and end cap can cause leakage. The O-ring needs to be replaced.

Oil leakage between the relative motion surface of the piston rod and the guide sleeve may be due to damage to the Y-shaped seal ring or a pulled piston rod. The Y-shaped sealing ring needs to be replaced or the piston rod needs to be repaired.

3、 Unstable lifting or abnormal speed

Hydraulic oil flow problem: Poor quality or impurities in hydraulic oil can block the hydraulic circuit, resulting in slower speed or unstable lifting. Regularly replace the hydraulic oil and ensure its cleanliness.

Mismatch between cylinder diameter and hydraulic oil flow rate: The speed of the hydraulic lift is inversely proportional to the cross-sectional area of the cylinder piston rod and directly proportional to the hydraulic oil flow rate. When the speed of the hydraulic elevator slows down, priority should be given to analyzing from the perspective of hydraulic oil flow and checking whether the diameter of the oil cylinder is fixed and unchanged.

The composition of the lifting circuit: The composition of the lifting hydraulic circuit will affect the output speed of the hydraulic cylinder. It is necessary to check whether the oil pump, overflow valve, directional valve and other components are working properly.

Load variation impact: The degree of impact of load variation on speed is represented by speed stiffness. When the load changes, the output speed of the hydraulic cylinder will change. Speed stiffness needs to be improved by adjusting the throttle valve area or increasing the fuel supply pressure.

4、 Control system malfunction

Control panel and joystick issues: Malfunctions in the control panel or joystick can cause unstable crane movement or incorrect load positioning. Check if the connection between the control panel and the joystick is good, and replace any damaged components.

Electrical connection or sensor issues: Loose electrical connections or sensor failures can affect the normal operation of the control system. Check if the electrical connections are secure and replace damaged sensors.

5、 Other common questions

Hydraulic oil contamination: Dust, debris, or moisture entering the hydraulic system can cause hydraulic oil contamination and damage to hydraulic components. Regular fluid analysis and appropriate filtration systems need to be implemented to ensure that hydraulic oil remains clean and free of contaminants.

Cylinder drift: Even when the control valve is in the neutral position, cylinder drift occurs when the hydraulic cylinder slowly moves or descends under load. This may be caused by internal leaks in the cylinder or worn seals. Regular inspection and maintenance of hydraulic cylinders and seals are required.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment