The engineering machinery outlet sound troubleshooting and improvement measures

The engineering machinery outlet sound troubleshooting and improvement measures - 2020 05 - Tan Lin the new chapter 26 ( Guizhou ZhanYang power heavy industry co. , LTD. Product research institute) one Fault phenomenon in our ma chine found to a certain type of engineering machinery, engine accelerator pedal control, the hydraulic system oil return filter in a larger 'goo goo goo sound, with a manual knob and control the throttle when there was no sound. When used to test the type of engineering machinery, oil return filter is not sound, problems that the batch return oil filter. two The troubleshooting of the engineering machinery hydraulic system outlet hydraulic oil through the radiator, oil filters, in turn back pressure valve, finally reached the hydraulic oil tank, as shown in figure 1 a. Radiator set a bypass valve, in case of congestion, the radiator of the hydraulic system oil through the bypass valve, oil filter and the back pressure valve flow back to the hydraulic tank. Oil filter set back the back pressure valve and bypass valve, if return oil filter clogging, the hydraulic system oil return successively by bypass valve and back pressure valve flow back to the hydraulic tank. Back to the oil filter bypass valve and the back pressure valve production into an organic whole, composition of the oil filter assembly, its structure as shown in figure 1 b. We check the oil return filter is very clean, so back to the oil filter bypass valve does not open, not happen sound. After carefully distinguish between the sound and found that the sound from the upper part of the oil return filter back pressure valve. In order to find the cause of the problem, we use the accelerator pedal control motor speed, measured back pressure valve inlet P2 points P1 and hydraulic oil tank entrance pressure value ( See figure 1) 。 Different temperature, different engine speed hydraulic oil when the back pressure valve opening pressure, as shown in figure 2. The oil return filter upper back pressure valve opening pressure set point is zero. 2 mpa, the test data show that the sound back to the oil filter back pressure valve opening pressure is obvious more than this value. We corrected the back pressure valve spring pre-tightening force, but with the accelerator pedal control engine speed occasionally occur sound, shows that the size of the spring pre-tightening force is not the cause of sound. Back to the oil filter back pressure valve structure as shown in figure 1 b. We have to sound of the oil filter assembly and not sound back to the oil filter assembly and dismantling and comparison, discovered that the back pressure for the batches of the oil filter assembly fitting clearance between the valve core and guide sleeve is 0. 4 to 0. 5 mm, clearance between the guide sleeve and the spring is 0. 6 ~ 0. Does not occur, were greater than 8 mm sound of the oil filter assembly back pressure valve fitting clearance. This decision, because the valve core and the guide sleeve clearance is too large, the guiding role of bad, couldn't keep his slide along the axis direction valve core, valve core and guide sleeve between the friction resistance increases, lead to the opening pressure increases. Valve core and the guide sleeve clearance is too large, will cause the untight seal valve core conical sealing surface. When back to the oil pressure changes quickly, can make the seal is open, closed, valve core oil again and again, through small openings untight seal, in an intermittent noise will appear 'goo goo goo' vision. With the accelerator pedal control motor speed, motor speed is not stable, make the hydraulic system of hydraulic pressure pulsation, the oil pressure changes faster, issued a 'goo goo goo sound apparent; Manual knob control engine speed, throttle is fixed in a certain range, stable engine speed, oil pressure is more stable, back pressure valve core is not in the open and close frequently, there would be no sound. 3. Improvement measures and effect according to the testing and analysis, we require the oil filter assembly manufacturers improve the back pressure valve machining precision and quality, reduce the guide sleeve and the valve core rod and the clearance between the guide sleeve and the spring, improve the slide guide sleeve and the valve core mating surface roughness requirements. We will improve after the oil filter assembly test after change to this type of engineering machinery, the back pressure valve pressure value basically stable at zero. Within the scope of 2 mpa, sound fault disappear. This article from the journal of engineering machinery and maintenance, 2017, 6