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Maintenance and maintenance of hydraulic pumps and motors

Maintenance and maintenance of hydraulic pumps and motors

[Abstract]:
Before installing the test drive, the fuel tank, piping, actuators (such as oil cylinders) and valves must be cleaned. The new oil poured into the fuel tank must be filtered by the oil filter to prevent oil contamination caused by the oil drum being unclean.

Maintenance and maintenance of hydraulic pumps and motors

 

First, the use of axial piston pump

1. Before installing the test drive, the fuel tank, piping, actuators (such as oil cylinders) and valves must be cleaned. The new oil poured into the fuel tank must be filtered by the oil filter to prevent oil contamination caused by the oil drum being unclean. 
 
2. After using the new pump for one week, filter all the oil in the fuel tank and clean the fuel tank and filter. Then replace the oil for 3~6 months according to the working environment of the system working environment, and clean the fuel tank once. .
 
3. It is strictly forbidden to remove the fuel tank cap due to system heat during use, and other measures must be taken (such as setting the cooler).
 
4. Questions about self-priming:
 
1 The distance from the center of the oil pump to the oil level is not more than 500mm, and the suction pressure should be within -125mmHg. Otherwise, cavitation will occur, causing damage to parts, noise, vibration, etc. (Figure 3-1)
 
2 Install a 150-mesh oil suction filter on the suction line. Some piston pump manufacturers stipulate that the oil filter should not be installed on the suction line, but the cleanliness of the liquid in the fuel tank should be strictly required. A line filter with a filtration accuracy of 25μ is installed on the pump outlet side.
 
3 The speed of the pump should not be greater than the rated speed.
 
4 The suction pipe diameter is not less than the recommended value (see the installation dimensions catalogue), and the suction pipe has a maximum of one elbow joint.
 
5 If the oil distribution plate needs to reduce the swash plate angle start, it can not guarantee self-priming. If the user needs a small flow rate, the variable mechanism should be used to change the flow rate after the pump is fully angled.
 
5, pouring self-priming
 
1 When the minimum oil level of the fuel tank is 300mm higher than the center of the oil inlet of the oil pump, the pump can start self-priming at a small angle.
 
2 The diameter of the suction pipe 3 is not less than the recommended value, and the diameter of the load-stop valve 2 should be twice the diameter of the suction pipe 3.
 
3 The length of the suction pipe of the oil pump is L<2500mm, the pipe elbow shall not be more than two, the distance from the suction pipe to the tank wall is H1>3D, and the distance from the suction pipe suction port to the bottom of the fuel tank is H≥3D.
 
4 For pumps with a flow rate greater than 160 L/min, reverse self-priming is recommended.
 
6. Self-priming of vertical installation oil pump
 
1 The distance from the oil pump suction port to the lowest surface is not more than 500mm.
 
2 The oil filling joint on the return pipe should be higher than the bearing lubrication line of the oil pump (end face of the shaft end flange cover)
 
7. In the case of the pressure inside the casing and the connection of the drain pipe, the casing of the oil pump sometimes has to bear a certain pressure. Due to the limitation of the oil seal (slewing seal) and the flange seal on the pressure compensation variable mechanism, the pressure inside the casing is not suitable. More than 0.16~0.2Mpa, and the venting tube can not be connected with other return pipes, and should be returned to the tank separately. There are several ways to connect the drain pipe.
 
1 In the general hydraulic system, the connection method in Figure 3-4 is used, and the pressure before the oil filter indicates that the value does not exceed 0.16~0.2Mpa.
 
2 When the pump is often operated at zero eccentricity or the system working pressure is lower than 8Mpa, so that the leakage of the pump is too small and the pump body is heated, the oil circuit of Figure 3-4 can be used for forced circulation cooling.
 
3 When the booster tank is used due to the needs of the hydraulic system, the pressure P≤0.16~0.2Mpa
 
8, working medium:
 
1 It is recommended to use domestic 20# or 30# hydraulic oil or wear-resistant hydraulic oil with viscosity equivalent to ISO-VG32~68. For other hydraulic oils with viscosity index greater than 90, moisture, ash and acid value in Wang must comply with relevant hydraulic oil. Provisions.
 
2 The normal working oil temperature is recommended to be 10~65oC. For special high temperature or low temperature pumps beyond this temperature range, 10# aviation hydraulic oil is recommended. And specifically negotiate with the manufacturer.
 
9, the start of the pump
 
1 After the oil pump is installed, the pump must be filled with clean hydraulic oil through the drain port on the pump casing before the first start. Otherwise it cannot be started.
 
2 Turn the coupling by hand to check whether the pump shaft is evenly rotated during rotation, whether the installation is firm or not loose, and whether the two couplings are concentric.
 
3 Check that the direction of rotation of the pump motor matches the specified direction of rotation. For pumps with oil flow reversible (such as servo variable pumps), check that the direction of the dial is consistent with the direction of the inlet and outlet (when the inlet and outlet oil is indicated by the pump's label, the pointer should be on the dial) Positive, vice versa).
 
4 There should be an empty load circulation loop in the hydraulic system, so that the pump will not start and stop when fully loaded. Non-party members will reduce the service life of the pump and cause motor overload. The safety valve adjustment pressure in the hydraulic system should not exceed 35.0Mpa.
 
5 When the pump starts, start and stop the start button several times to confirm that the oil flow direction is correct and the pump sound is normal and then start continuously.
 
10, the load is overturned
 
1 Low load operation: After the above preparations are completed, the pump is operated for 10 to 20 minutes under the pressure of 1.0~2.0Mpa.
 
2 Full load operation: After low load operation, gradually adjust the pressure of the relief valve and safety valve to the maximum pressure of the hydraulic system for 15 minutes to check whether the system is normal. If the oil leaks, the sound of the pump and hydraulic system is normal, the maximum temperature on the pump casing is generally 10~20oC higher than the oil temperature at the inlet of the oil pump in the fuel tank, which is normal. For example, when the oil temperature in the fuel tank reaches 65oC, the maximum temperature on the pump casing does not exceed 70~80oC.
 
3 After the above load is completed, the pump can enter normal operation.
 
4 The operating time under the highest operating pressure shall not exceed 10% of one cycle time, generally within 6 seconds.