Piston pump is a reciprocating pump, pump the volume attributed, by which the plunger shaft of the eccentric drive roll, reciprocates its suction and discharge valves are one-way valve. Relying on the plunger piston reciprocates in the cylinder, so that the volume of the cavity seal work to change the onset of end suction, pressure oil. What questions that appear simple piston pump, which affect how much? These we all know? Following small to see with how we deal with these shortcomings found and more common.
Because the piston is chosen splash smooth, when the oil level is below the lower limit of the rules, crankshaft and connecting rod with oil to tone down the oil supply bush and the journal constitute between missing, can not constitute satisfactory smooth film and then attack the adhesive wear, assuming no additional time oil occurs with the journal bearing dry grinding, seizures and even bush-burning axle trouble.
Piston and disadvantages of common treatment methods:
1. Hydraulic pump output flow missing or oil output
1) lack of intake. Element is the suction pipe on the road too much resistance or lack of oil up. As the pump speed is too large, the liquid level in the tank is too low, into the pipeline leak, oil filter blockage.
2) excessive leakage. Vacancy factor is the pump is too large, poor sealing composition. As with the oil pan with metal fragments, iron and other scratch, face oil spills; collaborative arrangements variable one-way valve sealing surface is not good, the bearing surface of the pump and oil pan with trachoma or grind marks and the like. You can check the pump body through the thick cloud of hydraulic oil pump is the difference between foreign substances damaged parts.
3) skew plate angle is too small, a small displacement of the pump, which requires scheduling variable piston, swash plate angle added.
2. The bit is not zero discharge of oil
When the variable type axial piston pump swash plate angle is zero is called the median, then the pump output flow should be zero. But sometimes the phenomenon median violation adjustment arrangement midpoint, still at the midpoint of the flow rate output. Its feature is the orientation of the controller violation, loose or harm from scratch requires zero, tightened or replaced. Pump viewpoint staying power is not available, the skew angle trunnion wear will attack this phenomenon.
3. Output flow is not determined
Output flow is not strongly associated with many factors related. Variable pump can be considered as poorly controlled variable arrangement configuration, such as foreign body into the variable arrangement marks in order to draw the control piston, grinding marks, scars, etc., constitute a control piston movement unstable. Because the energy amplifier missing or damaged parts, rich spring damper control piston poor performance, will constitute a control piston movement unstable. Unstable flow and pressure are generally not accompanied by resolute. Such shortcomings are generally open pump, replacement of damaged parts, increase the damping, and spring stiffness trek control pressure.
4. Output pressure disorders
The output pressure of the pump is selected by the load, approximately proportional to the input torque. Output pressure disorders, there are two drawbacks.
1) output pressure is too low: When the pump is self-priming under condition, if the inlet line leak in the system or hydraulic cylinders, check valves, valve and so have a greater leakage are cause pressure does not rise up. This need to find out at the leak, tighten, replace the seal, you can trek pressure. Or adjust the pressure relief valve has the disadvantage low pressure system falters, should re-adjust the pressure relief valve or repair. Assumed hydraulic cylinder and valve plate forming a plurality of leakage episodes of negligence, when severe, the cylinder may split, it should re-surface grinding collaboration or replace the pump.
2) the output pressure is too high: If the loop load continues to rise, pump pressure continues to rise, comes as normal. If the load is constant, the pump pressure load across the desired pressure value, you should check the hydraulic pump components other than such as directional valves, pressure valves, transmission equipment and oil return pipe. If the maximum pressure is too high, adjust the relief valve.
5. Vibration and noise
Vibration and noise with the emergence. They not only hazardous to the operator of the machine, but also impact on the environment.
1) mechanical vibration and noise: such as the pump shaft and motor shaft misalignment or dieback, bearing rotary shaft coupling hazards and equipment damage elastic pad loose bolts will attack noise. For high-speed transmission of large energy work or pump, when you want to keep checking records amplitude, frequency and noise of the components. Such as natural frequency roll frequency and phase of the pump pressure valve together, it will cause resonance, can change the pump speed to eliminate resonance.
2) flow pipeline attack noise: inlet pipe is too small, it flows into the oil filter through tone is too small or clogged intake air inlet pipe, oil excluded too high, the oil level is too low and the lack of high-pressure suction pipeline attack was hammering, will attack noise. Therefore, it is necessary to accurately plan the tank, precise selection filter, tubing and directional valve.
6. Pump overheated
Excessive heat pump has two elements, one mechanical inconsistent heat. Since the appearance of movement in conflict with dry or semi-conflict situation, conflicting heat moving parts. Second, the conflict liquid heat. High pressure oil leaked into the gap through a variety of low-pressure chamber, and many lost hydraulic energy into heat energy. So precise selection space between moving parts, fuel tank capacity and coolers, can eradicate excessive heat pumps and high oil temperature phenomenon. Other oil return back to the oil filter clogging constitute excessive back pressure, high oil temperature and will cause the pump to overheat.
7, piston oil spill
Piston oil spill following main elements:
(1) spindle shaft seal is damaged or shortcomings, scratches;
(2) Internal leakage is too large, oil seals constituting the pressure increases, and the seal hazard or out;
(3) vent pipe too small for too long, so that the seal leakage;
(4) external pump tubing loose fittings harm gasket aging or the onset of crack;
(5) variable scheduling loose bolts, broken seals;
(6) cast iron pump casing adverse trachoma or welding.