Statics, Materials and Motion
Friction, Bearings & Wear
13 min · 2 worked examplesFree
The losses that decide whether a mechanism runs sweetly or seizes, and how to choose what a shaft turns in.
After this lesson you can
- Use F = uN and know what it ignores
- Choose a bearing for a job
- Say what lubrication is actually doing
Friction in a mechanism
Friction resists motion and turns work into heat. In a mechanism it appears at every sliding contact, and it accumulates faster than most people expect.
Static friction is higher than kinetic, so a mechanism needs more force to start than to keep going. That difference produces stiction, the tendency to stick, break free suddenly, and overshoot, which is poison for precise positioning and is why a slow, accurate axis is harder to build than a fast one.
It is not entirely an enemy. Traction is friction, and so is a friction clutch or a brake. The engineering aim is to have it where you want it and remove it where you do not.
In the full lesson
- Friction in a mechanism
- Bearings
- Wear and lubrication
Free with an account. Read it, work the examples, answer the questions, then build it in the simulator.