Created on:2021-06-07 11:17

Operation and maintenance of hydraulic pump and motor

Operation and maintenance of hydraulic pump and motor

(l) Operation is to ensure the normal delivery of pressure oil to the system by hydraulic pump and the normal operation of hydraulic motor driving mechanism, including start-up, continuous operation and shutdown. The operation steps and precautions are as follows.

① Before operation, check whether the hydraulic pump and motor are installed correctly and reliably, whether the coupling is installed in accordance with the requirements, and whether the coupling is stuck when rotating by hand.

② During the initial use or operation after long-term storage, the pump and motor shell should be filled with clean working oil according to the requirements of the manual before starting, otherwise it is not allowed to start, and the steering of the components should be checked when starting.

③ The overflow valve in the system shall be adjusted to the lowest value, and it is strictly forbidden to start with load.

④ Before the first operation of the pump, the shell should be filled with oil (through the leaking oil port); when the pump is started for the first time, the open circuit should be adopted, and the system should be operated under the pressure free state, so that the hydraulic pump and circuit can be filled with oil and discharged quickly. When the air is completely discharged, the pressure can generally be established.

⑤ When starting, it should be inched first, and then run continuously after normal operation. After a certain period of operation, no adverse phenomenon occurs, and then gradually adjust to the required pressure and flow. The maximum regulating value of safety relief valve shall not exceed the specified value. Pump or motor out of service for more than three months and re-use, should be first idle half an hour. In case of abnormal temperature rise, leakage, vibration and noise of pump or motor during operation, stop the pump immediately for inspection.

⑥ When the pump and motor stop, it should be unloaded first and then stop.

(2) Inspection and maintenance inspection refers to checking whether the working state and function of components are correct, including observation, measurement and test run. Maintenance refers to ensuring the normal function of components, reducing wear and replacing worn parts, including cleaning and replacing parts, that is, replacing oil and seals.

① The precautions for inspection and maintenance are the same as those for other hydraulic components, and attention should be paid to safety, cleanliness, disassembly and replacement during inspection and maintenance.

a. Safety inspection and maintenance of hydraulic pump and hydraulic motor, the most important problem is to pay attention to safety. In order to ensure safety, do not loosen pipe joints, threaded connections or components when the system is under pressure, and do not use oiler for use and maintenance.

Because the operator's attention is often focused on the fault phenomenon, and ignore the potential danger. Therefore, the standardized shutdown procedure should be implemented before the component repair, and the standardized restart procedure should be implemented when the component is to be put into operation again after repair.

The shutdown procedure is as follows: lower the suspended load or provide mechanical support to it - release the system pressure and disconnect the electrical control system and power supply.

The restart procedure can refer to figure B.


b. When repairing the hydraulic pump and motor cleanly, we must do our best to pay attention to the absolutely clean condition, because most of the faults of most hydraulic systems are caused by pollutants. It is not allowed to grind and weld on the site of repairing hydraulic pump and motor. Clean the outside of the thread before loosening it. Piping, oiling and flushing are important links to keep clean. The precautions are as follows.

i. When the pipe fittings connected with the pump and motor are damaged, they should be replaced immediately. When selecting the pipe, hose, threaded joint or flange, the rated value (i.e. wall thickness, material, etc.) should meet the use requirements. Seamless steel pipe shall be used for hard pipe. The steel pipe and metal pipe joint must be absolutely clean before installation, and there shall be no dirt, rust, welding slag, chip, etc. It can be cleaned by wire brush, pipe washer or pickling. Before pickling, the pipes should be degreased and cleaned thoroughly after pickling. After cutting, taper holes should be reamed on the inner edge of the pipe to remove the possible burr, but the holes should not be reamed too much to avoid weakening the connection. The pipe shall not be welded after assembly. The hose should be bent a few more times to release trapped dirt. The pipe shall be annealed before bending to prevent wrinkling or flattening during bending. To accurately bend the pipe, the pipe can be in place without elastic deformation. The flange must be flat on the mounting surface and fastened with screws of appropriate length. Before installation of threaded joint, check whether there is metal burr on the thread. Sealing tape is not allowed on straight thread. If the catheter is to be stored for a period of time, the nozzle should be blocked to prevent the invasion of foreign matters. In order to prevent pollution, it is not allowed to use rags or other things to block the pipe orifice, and the sealing cap with appropriate size should be used.

II. The oil tank shall be stored horizontally, indoors or in the shed as far as possible. Before opening the oil barrel, thoroughly clean the top and mouth of the barrel to prevent soil and other external pollutants from entering the oil. Only clean containers, hoses, etc. are allowed to transfer oil from the oil drum to the oil tank. It is recommended to use oil pump with 25 μ M filter. Provide 200 mesh filter screen in the oil filling pipe of oil tank. Ensure that the filter is designed for the type of fluid required by the system. New oil should also be filtered.

III. before flushing, the precise system components shall be removed and the short connector or hollow part shall be installed in its position. Remove the system filter element from the main pipe being flushed. The flushing flow should be 2-2.5 times of the expected flow of the system. If possible, use a hot wash solution (85 ℃). Only one branch is flushed at a time, starting from the circuit closest to the flushing pump and advancing downstream in turn. For this reason, it may be necessary to add a stop valve in the system. System pumps cannot be used as flushing pumps. In general, power pumps, such as centrifugal pumps, can provide enough water head and large flow, operate economically, and have good tolerance to circulating pollutants during flushing. A flushing filter with a capacity matching the flow rate used is used in the flushing system. The filtration accuracy shall be as high as possible and shall not be lower than that of the recommended system. If possible, use an auxiliary flush tank to avoid contaminants trapped in the system tank. An oil sampling plan shall be established to check the contamination level, so as to determine when to end the flushing procedure. After flushing, all measures shall be taken to prevent contamination during reassembly of working elements.

c. Disassembly and replacement in the disassembly and replacement of hydraulic pump and hydraulic motor general precautions are shown in the table.


Matters needing attention in disassembly and replacement of hydraulic pump and motor

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General users of hydraulic technology should not disassemble and repair hydraulic pumps and motors by themselves. Due to the limitation of drawings, accessories and experimental means, improper repair may cause serious accidents, so the pump and motor to be repaired should be sent to the manufacturer for repair as far as possible


During assembly, special attention should be paid to prevent parts from being polluted again and foreign matters from falling into the components


Confirm that the components with internal pollution or factory leaving, long storage time and natural aging of seals should be disassembled, washed and tested according to the situation


Each thread or screw joint (including oil port thread or flange screw) must be evenly tightened to the specified torque to prevent oil leakage or air leakage due to insufficient torque, or component deformation due to excessive torque, which will affect the work


During disassembly, it is suggested to record the disassembly sequence of each part, so as to install it correctly and smoothly after disassembly and washing


After disassembly and repair, the reassembled hydraulic pump and motor should be tested on the test bench to ensure the volumetric efficiency under rated pressure and rated flow


The disassembly and washing work should be carried out on the basis of full research and understanding of the product samples, operation instructions and other relevant technical data of the components, familiarity with and mastery of the function, specific structure, working principle and characteristics of the components, determination of the correct disassembly purpose and sequence, and preparation of tools, seals of hydraulic pump and motor transmission shaft, and various O-rings and other materials


The regulator of variable pump and variable motor should be reset


Parts and old seals that do not meet the requirements must be replaced and are not allowed to be used again


When it is confirmed that the components are not necessary for disassembly and maintenance, but need to be replaced, the model of the replaced components must be correct. If you can't find the same type of components before using similar components, you should pay attention to the function, parameters, connection size is consistent, but also pay attention to the installation position, ambient temperature, etc




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