Discussion on the Destruction Principle of Hydraulic Seals of Hydraulic Breaker

Hydraulic breaker is the first of the common construction machinery and equipment, because hydraulic breaker has a series of advantages of wide acceptability and high working efficiency, and it is used in mining, metallurgical industry, transportation, railway lines, tunnel construction and other manufacturing industries. Hydraulic breakers rely on the power system of the hydraulic machine, which has the effect of impact and crushing. Because the application load of hydraulic breakers is relatively extreme, the repair rate is relatively high, and the service life of hydraulic seals is widely and relatively short, especially in large diameters. hydraulic breaker. In the application of hydraulic breakers, the natural environment, actual operation, components and other factors will lead to common failures of hydraulic breakers, such as poor impact continuity, reduced impact force, insufficient impact frequency, abnormal oil pipeline vibration, and oil leakage. failure, which will cause the reduction of the hydraulic breaker's action and high efficiency, and will lead to a safety risk in the actual operation of the crushing. The hydraulic seal is the first part of the hydraulic breaker. This paper discusses the destruction principle of the hydraulic seal of the hydraulic breaker. There are many reasons for the initial ineffectiveness of hydraulic seals. The key reasons can be sorted into the following aspects: 1. The initial damage of hydraulic seals caused by axial force: Because the office environment of the breaker is complicated, the axis of the drill rod is most prone to inclination. When the piston moves to the end of the drill rod, the recoil force suffered by the piston rod is an axial force, and one force of this force generates an axial force on the piston rod, and the piston rod is on one side under the effect of the axial force, and the impact The hydraulic seal is damaged due to the side of the hydraulic seal. At the same time, the gap between the original piston rod and one side of the cylinder wall subsides, the oil slick is seriously damaged, and dry friction occurs, which quickly contuses the surface of the piston rod and the engine cylinder. The key reasons for the axial force are invalid and non-standard actual operation of the drill rod guide sleeve, poor lubrication of the guide sleeve or poor wear resistance of the guide sleeve, accelerated damage of the guide sleeve, drill rod and guide sleeve. The gap of the sleeve is sometimes about 12mm, and the axis of the drill rod is most likely to be inclined at this time. Excessive clearance of the piston rod, bending of the drill rod, wrong type and specification of the drill rod are also very easy to cause axial force on the piston rod. Countermeasures: The guide sleeve must be regularly checked and filled with high-temperature grease, and if the gap is too large, it should be replaced immediately. Standard practice minimizes the contribution of axial forces. The breaker manufacturer can improve the construction and reduce the damage of the axial force to the hydraulic seal and the piston rod. 2. Cavitation and cavitation lead to rupture and melting of hydraulic seals, and the air tightness is corroded. Reason: When the working pressure of the system software changes, the gas or vapor bubbles that do not dissolve the compressor lubricating oil accumulate in the sealing gap, and the bottom pressure side of the structural edge, etc., swells and cracks, releasing equivalent to large kinetic energy, resulting in The surrounding hydraulic seals are corroded, broken, embrittled and even melted; when the working pressure of the system software increases significantly within a very short interval, the heat transfer in the bubble is reduced, and the gas in the bubble, Compressor lubricant particulate compounds can be ignited by energy levels, detonated at hydraulic seals (Diesel effect), and ignited hard particulate deposits will aggravate common failures in system software. Because the breaker is often tilted during work, the load is large, high-frequency vibration and angle difference occur, and weak points are generated on the hydraulic seal. At this time, under the high frequency linear motion of the piston rod, the high pressure and low pressure change, the oil will continue to impact, and the cavitation will appear more than the Diesel effect, which will greatly reduce the service life of the hydraulic seal, and finally lead to the leakage of the gas and the leakage of the gear oil. Go to the N2 room, causing the hammer to leak, and everything can't work normally. Countermeasures: Use high-quality gear oil to replace the filter element every quarter, improve the system software exhaust pipe, and reduce the whole process of special work;