Repair technology is one of the three basic technologies for mechanical equipment maintenance. Reasonable selection and application of repair technology is an effective measure to improve the maintenance quality of diesel generator sets, save resources, shorten downtime and reduce maintenance costs. There are many repairing methods for parts. Through long-term practice, mechanical processing, pressure processing, metal-spraying, welding repair, electroplating and-bonding are commonly used in production. It should be based on the principle of mainly repairing and supplementing. Under the conditions of economic and reasonable conditions, vigorously promote and adopt effective and advanced repair technology. The following is a detailed description of the machining and repair technology of diesel generator sets.
Machining is the most important, basic and most widely used process in the repair of parts. It can be used as an independent means to directly repair parts, or it can be an essential process for the preparation or final processing of other repair methods such as welding, plating and coating. It mainly includes several repair methods such as partial replacement method, transposition method, nesting method, adjustment method and repair size method.
I Partial Replacement Method
If a part of the part is seriously damaged and the other parts are still intact, it is generally not appropriate to scrap the entire part. The worst part can be removed, a new part can be re-created, and the newly replaced part can be connected with the basic part of the original part in a certain way to restore the part’s ability to perform the repair. The method is called the partial replacement method. For example, if the gear of a heavy machinery is damaged, the damaged ring gear can be annealed and then pressed into the new ring gear. The new ring gear can be machined in advance or can be processed after pressing. The connection method is by key or interference connection, and can also be fixed by fastening screws, rivets or welding. The partial replacement method is especially suitable for the case where the multiple gears are partially damaged or the structurally complicated ring gear is damaged. It can easily repair the process and expand the repair.
II Transposition Method
Some parts of mechanical equipment, due to their use characteristics, usually produce unilateral wear or wear with a viscous directionality, and the other side of the symmetry wear less. If the structure allows, you can use the worn side of the part and install it in one direction to continue using it without the need to completely repair the part. This method is called the transposition method. For example, the two ends have the same structure, and only the long lead screw that transmits the power function and has no precision requirement, and the local wear adjustable head is used. In the large crawler walking mechanism, most of the rail chain pins are unilaterally worn, and the function of the crawler belt can be restored by rotating it 180 degrees during maintenance, and the rail chain pin can be fully utilized.
III Nesting Method
The insert is to fit the inner or outer bushing on the worn bearing hole or journal with a certain interference, and then machine to the original basic size or intermediate repair size, thereby restoring the fit clearance of the tissue member, as shown in the figure 2-16.
Figure 2-16 shows the frictional torque applied to the inner and outer bushings. Both the inner and outer bushings are fitted to the parts to be repaired with an interference fit. The sized of the fit interference should be calculated according to the torque and friction. Sometimes it can be fixed by other methods using screws and spot welding. If it is necessary to increase the hardness of the inner and outer bushings, heat treatment should be carried out before pressing. This method can only be used if it is allowed to reduce the journal or enlarge the hole.