What are the disadvantages to placing three or more support bearings on a long drive shaft?
In my design I have a 1-1/2″ diameter ~5′ long drive shaft. The input pulley is at one end and there are two output pulley’s, one ~1/3 of the length of the shaft in from the input pulley and the second is at the opposite end. Currently supported in bore of the input pulley and at the end of the shaft. What are the disadvantages of placing a third bearing support on the shaft?
Karthick:
Eli’s original post indicated that the shaft was approximately 5 feet long or three time the 1.66′ length you mentioned.
This would put the two of the bearing at the distance you stated. the other two would be 3.33′ apart.
Niel
If that input shaft (1.66feet) was straight position no need to give a bearing. if that input shaft was in inclined postion we have place the bearing on it.
The biggest disadvantage with putting a third bearing on the shaft is the need for precise alignment between all three bearings. The cost to install the third bearing will be nearly as much as the cost to install the original two bearing.
Niel Leon
Community Developer – Engineering.com
