Issues Related To The Polishing Process Of Crankshafts in Natural Gas Generator Sets

The polishing process of the crankshaft of a natural gas generator set is one of the key processes to ensure the quality of repair. When using the outer surface of the timing gear journal and flywheel flange as the reference for grinding paste, the curvature must be corrected before grinding, and the runout of the middle main journal before grinding must not exceed 0.3 millimeters. If the bending is not corrected in advance, the weaving and cutting will cause the crankshaft to produce a new axis that intersects with the original flywheel flange and timing gear axis, changing the turning radius, damaging the dynamic balance force, shortening the service life, exacerbating the wear of related parts, making loud noises from the timing gear, leaking the rear oil seal, and increasing the unbalanced rotational mass of the engine.
Strictly ensuring that the size of the crankshaft journal fillet radius of the natural gas generator set meets the requirements of the drawing is one of the key issues in repairing quality. However, most car repair shops do not pay enough attention to this, and grinding wheels are rarely used for grinding. The rounded corner radius of smooth grinding is often smaller than the specified size. According to statistics, if the fillet radius is less than 2.5 millimeters, its fatigue strength is only 80% or less of that of a fillet radius of 2.5 millimeters. Due to the frequent use of the grinding wheel fillet corrector attached to the grinding machine for polishing the crankshaft, the fillet size meets the requirements. Therefore, since the production of vibration welding, there has been no occurrence of shaft breakage.
During the operation of natural gas generator sets, the crankshaft experiences high sliding speeds on various friction surfaces and poor heat dissipation conditions due to complex forces and working conditions. Therefore, the main journal and connecting rod journal of the crankshaft inevitably experience wear during operation, and the wear is uneven, mainly manifested as roundness of the journal, exceeding the standard value of cylindricity, and pulling. The most worn part of the connecting rod journal is usually on the inner side of each journal, that is, on the side closer to the crankshaft centerline, causing the journal to lose its roundness; The parts that wear into a conical shape are generally located on the side where impurities adhere to the lubricating oil passage and on the parts under high stress. The wear parts of the crankshaft main neck vary depending on the degree of engine strengthening, number of cylinders, crankshaft length, and balance weight of the balance block, and are relatively more evenly worn compared to the connecting rod neck. Practice has shown that the wear of the connecting rod journal is faster than that of the main journal, but the consequences of the main journal wear are more severe than those of the connecting rod journal wear.
Inspection and treatment methods for natural gas generator sets. According to the wear pattern of each journal, the worn parts can be identified, and the roundness and cylindricity can be measured using an outer diameter micrometer to determine the repair level and grinding size of the crankshaft.
The polishing process of the crankshaft is one of the key processes to ensure the quality of repair. When using the outer surface of the timing gear journal and flywheel flange as the reference for grinding paste, the curvature must be corrected before grinding, and the runout of the middle main journal before grinding must not exceed 0.3 millimeters. If the bending is not corrected in advance, the weaving and cutting will cause the crankshaft to produce a new axis that intersects with the original flywheel flange and timing gear axis, changing the turning radius, damaging the dynamic balance force, shortening the service life, exacerbating the wear of related parts, making loud noises from the timing gear, leaking the rear oil seal, and increasing the unbalanced rotational mass of the engine.
Strictly ensuring that the size of the crankshaft journal fillet radius meets the requirements of the drawing is one of the key issues in repairing quality. However, most car repair shops do not pay enough attention to this, and grinding wheels are rarely used for grinding. The rounded corner radius of smooth grinding is often smaller than the specified size. According to statistics, if the fillet radius is less than 2.5 millimeters, its fatigue strength is only 80% or less of that of a fillet radius of 2.5 millimeters. Due to the frequent use of the grinding wheel fillet corrector attached to the grinding machine for polishing the crankshaft, the fillet size meets the requirements. Therefore, since the production of vibration welding, there has been no occurrence of shaft breakage.