The stability of the hydraulic cylinder directly affects the working efficiency and safety of the construction machinery and equipment, and is an important actuator in the work of engineering machinery and equipment. There is a problem with the hydraulic cylinder seal. The piston rod seal is leaking out. There may be problems with the quality of some components and cause premature leakage. Among the various hydraulic equipment manufacturers, there are also many countermeasures prepared for this, but it is obviously imperfect.
First, the external leakage phenomenon of the hydraulic piston rod seal is gradually analyzed
Most people believe that the main cause of leakage outside the hydraulic piston rod is seal failure and oil contamination. Through the disassembly of the hydraulic cylinder that was returned due to the leakage of the piston rod in the market, it was found that the sealing ring showed different degrees of wear, scratching and aging.
Why is the dust seal of the dust seal bad?
The multi-purpose application of construction machinery, in the face of mechanical high temperature working conditions and long working hours, the dust ring must have high anti-pollution and high temperature resistance. The assembly process of the dust seal should be careful and protect the protective measures. The dust seal of the hydraulic cylinder does not take protective measures. For example, during the painting process, residual paint and damage may occur in the lip of the dust ring. When the dust is too serious, Add a dust jacket to protect the seal. These conditions should be noted in advance.
Is the structure of the combined seal ring used for the shaft suitable?
The main sealing structure of the piston rod is the combination of the dustproof ring and the high pressure sealing ring or the low pressure combined sealing ring. Although the imported combination y-type sealing ring is more expensive, there is basically no leakage phenomenon, and if the sealing member lip angle is designed Improper, it is easy to cause the material flow problem at the high temperature of the lip, and the size and shape of the sealing lip are changed, resulting in failure of the sealing performance.
Is there any bump on the surface of the piston rod?
A cross-sectional inspection of the piston rod seal through the hydraulic cylinder is a significant scratch. During the lifting process of the loader, the material in the bucket is slipped and hits the surface of the piston rod, causing micro-pits on the surface of the piston rod, thereby increasing the friction between the seal ring and the piston rod, and causing the seal ring to wear out.
Is there a problem with the clearance between the piston rod and the guide sleeve?
According to the design principle of the hydraulic cylinder, the fitting tolerance of the piston rod and the guide sleeve is H9/f8. However, in actual life work, due to the overloading of the construction machinery for a long time, the material expands under high temperature conditions, which easily causes the oil film on the surface of the piston rod to drop sharply, and the lubrication effect of the sealing lip is reduced. The local temperature exceeds the allowable temperature of the sealing ring, causing the sealing ring to age and lose. Sealing effect. This is also the reason why the piston rod sealing surface is black.
Second, how to reduce or reduce the leakage phenomenon of the hydraulic piston rod seal?
A correct response is more effective than half of the response.
A. Select the inner and outer double lip dust seals to prevent dirt from entering the hydraulic cylinder from the lip and the bottom of the groove. A protective plate is added to the piston rod earring to effectively reduce and avoid the hidden danger of the piston rod
B. During the work of the sealing ring, the protective measures for the mechanical painting process are added. Like the experience of foreign hydraulic cylinder dust-proof protection, it is necessary to install a special sealing ring at the lip of the dust-proof ring to effectively isolate it. Then remove the special seal and install the dust ring.
C. Improve the shaft seal assembly to avoid flow problems at the seal lip and edge material at high temperatures.
D. The piston rod surface is medium frequency quenched. Through medium frequency quenching, the hardness of the piston rod base body can be increased, which can increase the anti-collision capability of the piston rod surface and reduce the surface roughness of the piston rod. In addition, the plug rod forms a cylindrical structure, which can improve the bending strength of the piston rod.
E. Reasonably design and match the matching clearance between the piston rod and the guide sleeve. Ensure the lubrication of the lip of the sealing ring and avoid abnormal high temperature due to friction.