On the basis of the previous section described the working principle of hydraulic pressure oil spill loop, if the yaw brake seal structure of seal failure, will cause the hydraulic oil leakage in great quantities, and the hydraulic system pressure drop quickly, and met the scene actual situation did not appear a large number of oil spill, system pressure and no obvious change. Therefore, the direct cause of hydraulic oil leakage is that the pressure between the dustproof ring and the sealing ring is beyond the tolerance of the dustproof ring. The pressure between the dustproof ring and the sealing ring is caused by the hydraulic oil in the return tubing of the fuel tank, which is calculated as equation (1).

 

 

P = TGH (1)

 

 

In the formula, it is the hydraulic oil density, 800kg/m3;

 

 

G is the acceleration of gravity, 9.85m/s2;

 

 

H is the height difference between the fuel tank and the yaw brake, according to 3m.

 

 

By type (1) calculation, the hydraulic oil pressure is 23640 pa, and fuel tank should be connected with atmospheric, internal negative pressure, and shield can withstand the minimum pressure of 50000 pa, so in theory the yaw brake of the leakage of hydraulic oil should be back into the tank.

 

 

After investigation and research, it is concluded that the possible reasons for leakage of oil leakage circuit include the following three aspects:

 

 

(1) failure of the dustproof ring;

 

 

(2) there is negative pressure inside the tank;

 

 

(3) the drainage channel on the hydraulic valve block is connected with the relief oil road.

 

 

The reason (1) is inconsistent with the actual situation, and the condition of (2) is not valid. So initially determined the leakage of oil circuit for the leakage of the valve block the leakage of oil and oil and other oil pressure connected, make leaking oil terminal in additional pressure, oil circuit of the hydraulic oil leakage.

The above:Surface adhesion repair technology of hydraulic gear pump