The selection method of the connecting rod bushing of a
diesel generator mainly includes the following steps and precautions:
1. Select a suitable bushing: When replacing the piston pin, a suitable connecting rod bushing should be selected. If the bushing is worn too thin, a new bushing should be replaced. The newly selected bushing should have an interference of 0.04-0.10mm to ensure that it fits tightly with the inner diameter of the small end of the connecting rod.
2. Check the matching of the bushing with the inner diameter of the small end of the connecting rod: The newly selected bushing should have a certain processing allowance, which should not be too large or too small. If the processing allowance is too large, too many reaming times will easily cause the inner hole to deflect; if the processing allowance is too small, it is not easy to ensure the quality of repair. The empirical judgment method is: before the bushing is pressed into the small end of the connecting rod, try it with the selected new piston pin. If it can be barely put on, it is suitable.
3. Install the bushing: When installing the connecting rod bushing, you can use a punch to punch it in or press it in with a vise. If conditions permit, it can be done on a press. When installing, pay attention to aligning the oil hole of the bushing with the oil hole on the small end of the connecting rod. If there is no oil hole on the new bushing, drill the oil hole before pressing it in.
4. Reaming and trial fitting: During the reaming process, the reamer should be selected according to the actual size of the piston pin and the position of the reamer should be adjusted. When reaming, the force should be applied evenly to keep the connecting rod and the reamer at right angles to prevent the reaming from being biased. After reaming, the piston pin should be frequently used for trial fitting to prevent the reaming from being too large. When reaming to the point where the piston pin can be pushed into the bushing 1/3-2/3 with the force of the palm, the reaming should be stopped and scraped.
5. Scraping and inspection: Scrape with a scraper according to the contact surface and tightness of the piston pin and the connecting rod bushing of the generator set. After scraping, it should meet the requirements in the manual of each machine. The inspection method is: apply engine oil to the piston pin, push the piston pin into the connecting rod bushing with the power of the palm, and if there is no gap, the tightness is considered appropriate; if the contact area is more than 75%, and the contact points are evenly distributed and the weight is consistent, the contact surface is considered to meet the requirements.
