Definition

Noun: A mechanical assembly, specifically a system of gears, in which at least one gear (a planet gear) rotates on an axis that itself moves around a central, fixed axis. This arrangement is used to achieve high gear reduction ratios in a compact space.

Usage

The term "epicyclic train" is a technical noun used in mechanical engineering and gear design. It describes the specific configuration of the gear system. * An epicyclic train is fundamental to the operation of an automatic transmission. * The design of the epicyclic train allows for different output speeds without disengaging gears.

Examples

• The engineer analyzed the epicyclic train to calculate the final drive ratio.
• Planetary gearboxes utilize an epicyclic train for their compact and efficient power transmission.

Advanced Usage

• Epicyclic Train Analysis: The process of calculating the rotational speeds and torque within the gear system using formulas like the planetary gear equation.
• Compound Epicyclic Train: A more complex system that uses more than one set of planet gears or carriers to achieve a wider range of gear ratios.

Variants and Related Words

• Planetary Gear Set: A common synonym for an epicyclic train, where the central gear is the "sun," the orbiting gears are "planets," and the outer ring is the "annulus" or "ring gear."
• Epicyclic Gearing: The broader concept or technology that employs an epicyclic train.
• Planetary Carrier: The component in an epicyclic train that holds the axes of the planet gears and revolves around the central axis.

Synonyms

• Planetary gear train
• Epicyclic gear train
• Planetary gear system

Related Concepts (Not Phrasal Verbs or Idioms)

• Gear Ratio: The ratio of input speed to output speed, which an epicyclic train is designed to modify.
• Torque Multiplication: A key function of an epicyclic train, where output torque is increased while speed is reduced.
• Fixed Annulus: A common configuration in an epicyclic train where the outer ring gear is held stationary.

Noun

1. a system of epicyclic gears in which at least one wheel axis itself revolves about another fixed axis