1 Damage of leaks
The hydraulic system leakage affects the peace of the system task, the formation of oily waste, purification of the surrounding environment, add machine to return time, declining consumption rate, increase consumption capital and the formation of fouling products, thus, the leakage of the hydraulic system we must grasp.
2 Causes of the leaks
The leakage of all the hydraulic system is in the use of a period of time after the following three causes caused by: (1) the impact and vibration forming pipe joints loose; (2) Dynamic seals and fittings wear each other (especially the hydraulic cylinders); (3) Excessive oil temperature and the incompatibility of the rubber seal with the hydraulic oil.
3 grasp the way of leakage
(1) Add shock and vibration
In order to increase the leakage caused by the loosening of the joints subjected to shocks and vibrations, the following methods can be taken:
① use damping bracket to fix all pipes to drain shock and vibration;
② use low impact valve or accumulator to add impact;
③ proper arrangement of pressure control valves to cover all components of the system;
④ to maximize the use of the number of fittings, pipe joints as far as possible with welding;
⑤ the use of straight threaded joints, tee joints and elbow replacement taper pipe threaded joints;
Try to use back oil block instead of each pipe;
For the use of the minimum pressure, the rules of the installation of the use of bolt torque and plug torque, hydraulic cylinders to avoid joint face and sealing pieces are swallowed;
To install the fittings accurately.
(2) Wear of added dynamic seals
Most dynamic seals have been accurately designed, if the dynamic seal processing passes, the installation is accurate, the use of reasonable, can guarantee a long time absolutely no leakage task. From the design point of view, designers can take the following ways to extend the life of the dynamic seals:
① removing the lateral loads on the piston rod and the driving shaft seals;
② use dust ring, shield and rubber cover piston rod, to avoid abrasive, dust and other impurities into;
③ design and choose suitable filtration installation and easy to clean the tank to avoid the accumulation of dust in the oil;
④ the piston rod and shaft speed can be low.
(3) Request for static seals
The static seal is avoided by the leakage of the oil liquid between the rigid fixed appearance. Reasonable design of sealing groove size and tolerances, hydraulic cylinders so that after the installation of seals to the affirmation extrusion deformation in order to fill in the appearance of the macroscopic depression, and the sealing of the stress in the progress to higher than the pressure sealed. When part stiffness or bolt preload is not large enough, with the appearance of oil pressure will be in the effect of the difference, forming gaps or increase because the sealing exterior is not flat and can be from the beginning of the gap. Welded pipe with the appearance of static, static seal is a dynamic seal. The coarse mating exterior will wear seals, changing clearance will swallowed seal edges.
(4) Reasonable design and installation board
When the valve group or backplane bolts are fixed on the mounting surface, in order to obtain the initial seal and avoid the sealing pieces of extrusion groove and wear, the installation surface to be straight, sealing surface request finishing, the exterior roughness to reach 0.8 μm, three-dimensional degree to arrive 0.01/100mm. The appearance cannot have radial scratches, the cohesion of the screw must be sufficiently large to avoid the appearance of distinction.
(5) Grasp the oil temperature to avoid the seal transformation
Premature metamorphosis of seals can be caused by a variety of factors, one of the main factors is excessive oil temperature. The temperature of each 10 ℃ reduces the sealing piece life will halve, so should reasonably design the high efficiency hydraulic system or set the cooling installment, to maintain the oil temperature at 65 ℃ below, another factor can be the use of oil and seal data compatibility issues, should be used in accordance with the interpretation or relevant manual selection of hydraulic oil and seal of the type and material to deal with compatibility problems, extending the use of sealing components life.