Definition

1. Noun:
   • A type of gear consisting of a shaft with a screw-like thread (the worm) that engages with a toothed wheel (the worm wheel or gear). Its primary function is to change the direction of rotational motion by 90 degrees and provide a high reduction ratio in a compact space.

Usage

• Noun:
  • A worm gear is often used in applications where a large speed reduction is needed, such as in conveyor systems.
  • The advantage of a worm gear is that the worm can easily turn the gear, but the gear cannot turn the worm, providing a built-in braking feature.

Examples

• Noun:
  • The tuning mechanism on a guitar uses a worm gear for precise adjustment of the string tension.
  • Engineers selected a worm gear for the elevator's drive system because of its compact size and self-locking capability.
  • The rotary motion from the motor's horizontal shaft is transferred to a vertical shaft via a worm gear.

Advanced Usage

• "Worm gear drive": Refers to the complete assembly or system utilizing a worm and worm wheel.
  • The machine's low-speed, high-torque output is achieved through a worm gear drive.
• "Worm and wheel": An alternative term for the worm gear assembly, emphasizing its two main components.
  • The mechanism is a simple worm and wheel arrangement.

Variants and Related Words

• Worm (n): The threaded, screw-like shaft in a worm gear set.
  • The worm is typically made of hardened steel.
• Worm wheel (n): The toothed gear that meshes with the worm. Also called a worm gear.
  • The bronze worm wheel engages with the steel worm.

Synonyms

• Worm drive: A synonym emphasizing the function of transmitting motion.
• Screw gear: A less common term highlighting the screw-like nature of the worm.

Related Phrases

• Gear ratio (of a worm gear): The ratio of the number of teeth on the worm wheel to the number of threads (starts) on the worm. This determines the speed reduction.
  • A worm gear with a 40:1 ratio means the worm wheel turns once for every 40 turns of the worm.
• Self-locking (worm gear): A characteristic where the worm can drive the wheel, but the wheel cannot drive the worm, preventing back-driving.
  • The self-locking feature of the worm gear ensures the lift stays in position when the motor is off.

Noun

1. gear consisting of a shaft with screw thread (the worm) that meshes with a toothed wheel (the worm wheel); changes the direction of the axis of rotary motion