1. 1.Mild hydraulic jamming increases the frictional resistance of the moving parts (such as valve cores, blades, plungers, pistons, etc.) in the hydraulic components, causing slow action or even disordered action;
2. 2.Severe hydraulic jamming causes the moving parts in the hydraulic components to be completely jammed and unable to move, causing the phenomenon of inability to act, and the operating force of the handle increases.

Measures to eliminate hydraulic jamming:

1. 1.Improve the machining accuracy of the valve core and valve body hole, and improve their shape and position accuracy. At present, hydraulic parts manufacturers can control the shape accuracy of the valve core and valve body hole, such as roundness and cylindricity, within 0.003mm. Generally, hydraulic jamming will not occur at this accuracy;
2. 2.The 400-ton hydraulic machine opens several appropriately positioned pressure equalizing grooves on the surface of the valve core, and the voltage groove and the outer circle of the valve core are concentric. The small end of the conical shoulder faces the high-pressure area, which is beneficial to the radial alignment of the valve core in the valve hole;
3. 3.If conditions permit, make the valve core or valve body hole perform high-frequency small-amplitude vibration in the axial or circumferential direction;
4. 4.Carefully remove the burrs on the convex shoulder of the valve core and the sharp edge of the valve hole sinking groove to prevent bumping and injuring the outer circle of the valve core and the inner hole of the valve body;
5. 5.Improve the cleanliness of the oil.