The common adverse phenomena in the process of using oil pump by customers are insufficient suction, stuck, noise and so on. The causes of noise are complex. We look at what factors may cause abnormal sounds : 

( 1 ) Internal cause, the support points of the pump shaft include pump shaft sleeve, pump cover sleeve or bearing position with different center and dislocation, which interfere with the operation of the shaft, or the poor verticality of the rotor chamber, too small depth tolerance, too large or too small eccentricity lead to interference between the rotor and the pump wall, resulting in noise. 

( 2 ) external factors, working oil is too thick, negative pressure is too large ; air is mixed into the oil inlet, and cavitation occurs ; improper installation of oil pump / motor, coupling damage, resulting in poor concentricity, noise ; the pump body entering the foreign body causes noise. 

When the oil pump noise, first exclude oil viscosity is qualified ? Is the oil clean, and is there any foreign matter in the oil pump ? Is the connection with the motor correct ? Is the coupling damaged ? After eliminating various factors, consider whether the oil pump itself has a quality problem ( internal cause ), so that the noise source can be more comprehensively investigated, so as to fundamentally solve the abnormal problem.