Bearings guide or constrain motion between machine parts while supporting loads and reducing friction. This lesson introduces their purpose and the main bearing families.
A bearing is a machine element that constrains relative motion to a desired form while supporting one part against another. Depending on its design, it may permit a shaft to rotate, a drawer to slide, or a joint to pivot. A bearing can also restrict unwanted movement by controlling the directions of forces acting on the parts.
All flashcards
What is a bearing?
A machine element that supports and guides moving parts, permitting desired relative motion while restricting unwanted motion.
What is the difference between radial and axial loads?
A radial load acts perpendicular to a shaft's axis; an axial or thrust load acts along the axis.
How does a plain bearing work?
It supports a moving part through surfaces in rubbing contact, often using a lubricant to reduce friction and wear.
What distinguishes rolling-element bearings?
They use balls or rollers between bearing surfaces so motion occurs by rolling rather than predominantly by sliding.
How do fluid and magnetic bearings support loads?
Fluid bearings use a supporting liquid or gas film; magnetic bearings use a magnetic field to support the load.
Quiz questions
What is a bearing's main mechanical role?Answer: To support and guide parts while controlling their relative motion.
In which direction does an axial load act relative to a shaft?Answer: Along the shaft's axis.
Which bearing family places balls or rollers between bearing surfaces?Answer: Rolling-element bearings.
How does a fluid bearing support a load?Answer: By maintaining a liquid or gas film between load-bearing surfaces.
Why might a designer select a magnetic bearing?Answer: It can support a load without ordinary solid-to-solid contact.