In the hydraulic machine repair process, some relatively useful diagnosis method, the hydraulic machine fault diagnosis, can speed up the overhaul time, quickly found the trouble place, save time and effort.
  The first is the replacement method: the same type, with the same structure, the same principle of the hydraulic machine on the same components (replacement) installed in a consistent direction, can quickly prove whether the component is defective, reliable. The benefit of this approach is that, even if the repair skills of the lower level, but also can quickly use this method, the hydraulic machine to make the correct distinction and treatment. However, this method must be of the same type, the same structure, the same hydraulic principle and the same hydraulic components. Therefore, this method has great limitations and certain blindness.
  Second auxiliary Law: with the aid of the simple parts, the hydraulic components of the hydraulic defects are diagnosed.
  1, through the oil outlet, as by a hydraulic valve element oil inlet and an oil cylinder port, can be identified these hydraulic components is leaked.
  2, artificial reversing method with the pole to make hydraulic valve component reversing, can be diagnosed whether the valve is stuck, such as stuck, spool is not in place and other defects. This approach can not disassemble parts down if there is something wrong with the diagnosis of hydraulic components, to avoid excessive apart the amount of work, reduce the fault diagnosis time for quick diagnosis, especially for large cylinder sealing problems with useful good.
  Third experience: maintenance personnel through the theory of hydraulic system of hydraulic machine grasp, understand the structure and working principle of the hydraulic components, based on the rich practical experience, carries on the comprehensive analysis of hydraulic machine mistakes, make the correct diagnosis and agile. To sum up, the hydraulic machine generally occurred in the wrong parts and its reasons can be broadly divided into the following five aspects.
  (1) improper adjustment of hydraulic components, such as: hydraulic pump, oil motor, sequence valve, directional valve, relief valve, unloading valve, balance valve pressure and flow adjustment errors;
  (2) the seal parts are damaged or impurities, so that the hydraulic components can not work properly;
  (3) hydraulic components wear or damage, such as valve components sealing failure, spring failure, the gap is too large or too small;
  (4) the electric control organization of the hydraulic press is out of order, such as the malfunction of the relay, the bad contact or damage of the button, the incorrect installation of the electromagnet, the mistake of the motor phase line and the like, resulting in the malfunction of the hydraulic component or the mistake of the program;
  (5) assist the organization failure, such as limit switches range adjustment wrong or damaged, damaged pressure gauge, pressure relay damaged tank, filter mesh is too large or too small.
  Fourth, the sensory system of hydraulic machine fault diagnosis, that is often used the most widely used method.
  "Question": after asking the hydraulic press operator to understand the problem, this will help the repair personnel to diagnose and analyze the defects.
  "Look": after investigating the working conditions of the hydraulic press, investigating the pressure gauge and the pressure relay, the orientation sensor, etc., it can distinguish whether the operation of a hydraulic component is reliable or defective.
  "Listen": by listening to the hydraulic press operation system and hydraulic components announced whether abnormal sound, discrimination related to whether the normal operation of hydraulic components, such as cylinder unloading, vibration and noise of hydraulic system is too large; the reversing, the impact is too large; the pump sound is normal operation;
  "Touch": the same kind of touch helps to determine whether the components and systems work properly.
  Diagnosis way hydraulic machine fault although there are many, but a diagnosis approach is relatively insufficient, so the use of these methods, the use of hydraulic machine fault fault should be summed up with the skills, scientific instruments, so scientific, accurate, economic and fast to find the fault part of the hydraulic machine. The hydraulic machine normal operation as soon as possible.