I'm new to bearing use and I'm trying to decide on a type of bearing for my application. I have an actuator shaft that will be moving down axially and slightly rotating (plus/minus 5-10 degrees). I want to measure the linear displacement of the shaft and therefore am trying to make use of a bearing system to isolate the linear motion from the rotary. I have been thinking about using a rotary ball bearing fixed to the shaft on the inner race such that it rotates and translates with the actuator shaft. The outer race will therefore only move linearly, and from this I will measure the linear motion using an encoder. Furthermore, I'm looking for something as small and light as possible to reduce weight impact on the actuator.
I understand this design may be a bit crude and so i was wondering if any suggestions on bearing design/choice to capture the linear motion from a translating and rotating shaft?
Any help would be much appreciated.