Analysis of Damage and Disassembly of Cycloidal Pin Reducers
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This post was last edited by 344198329 on 2017-7-7 11:00. The pin pins and eccentric bearings of our company’s cycloidal pin reducers were replaced after they became damaged. It was used for two months and then stopped working yesterday. When it was opened, that’s what was inside. The analysis shows that after the bearing was damaged, iron debris got involved in the friction process, which in turn damaged other components such as the cycloidal pins. I would like to ask: is this type of damage caused by an incorrect model, a quality issue with the bearing, or a problem with its proper alignment? Such problems have occurred already after just 2 months; in my opinion, it’s due to alignment or installation issues. But the mechanic’s explanation was that it was a bearing quality issue, and I have serious doubts about this. So I would appreciate it if everyone could help analyze it. Thank you.
Most are caused by overload, lubrication issues, and bearing quality.
Just talking about it isn’t enough to determine the cause. I have another question: isn’t there any quality inspection for the installation of the reducer? If so, how would one say that the installation quality is poor? The severity of the damage indicates that the issues were not detected in time, and the routine inspections were ineffective. The reason for the damage mentioned upstairs seems quite plausible ； Unless there is solid evidence, claiming that there are issues with the installation quality is a severe blow to the maintenance staff and lacks credibility.
Agree with the opinion from the 2nd floor: the retainer is broken, and there are grooves on the inner ring; the quality is indeed questionable
Thank you; I have also taken this issue into consideration, my own doubts. It wasn’t said. Because it’s uncertain. So I’ve come back to Haichuan to ask everyone. I also want to ask whether there are specific numerical values for judging the sound and vibration during routine inspections of cycloidal gear reducers Shouldn’t a quality issue with bearings last around 2 months? How can I determine the maximum load of this reducer? The current load isn’t even reaching the theoretical maximum load Thanks.
The last image shows whether the bearing is installed in the wrong direction; under normal circumstances, such bearings are installed back to back, not in the same direction. If they are installed in the same direction, at least 3 such bearings should be installed, and definitely one pair of them will be installed back to back.
When damage occurs, check the lubrication – whether there is sufficient oil and what the oil level is. In this type of design, the oil level is very important; otherwise, the bearings on the input shaft will not be properly lubricated, leading to damage. The reducer uses a shoulder for positioning, so moderate errors do not pose a major problem. It is important that the two pinions are installed according to the markings; if they are not aligned as specified, it will result in extremely high radial forces on the bearings, inevitably causing damage. Quality issues with the bearings are difficult to determine.
For this device, the upper part is 6408 and the lower part is NJ407; there is no such thing as installing them in reverse order. The 6408 is used for positioning
Both sets of bearings shouldn’t be deep groove ball bearings; the lower one should be of the NJ series.
Our factory has completely phased out cycloidal pinwheel reducers
The problem is likely due to internal impurities, or impurities introduced during installation or refueling. It will not be damaged as long as the above requirements are met.