Definition

Noun: A rocker arm is a pivoting lever used in internal combustion engines to transfer motion. Specifically, it converts the upward movement from the camshaft's cam lobe into a downward movement to open an engine valve.

Usage

The term rocker arm is a technical noun used primarily in mechanical and automotive engineering contexts. It refers to a specific engine component.

Examples: * The mechanic replaced the worn rocker arm to stop the ticking noise from the engine. * In a typical valve train, the rocker arm pivots on a shaft to push the valve open. * Proper lubrication of the rocker arm is essential for engine longevity.

Advanced Usage

• Rocker Arm Ratio: This refers to the mechanical advantage of the rocker arm, calculated by comparing the distance from the pivot point to the valve contact side versus the distance to the cam (or pushrod) contact side. A higher ratio opens the valve further for a given cam lift.

Variants and Related Words

• Valve Rocker: A synonymous term for rocker arm.
• Rocker Shaft: The shaft on which multiple rocker arms are mounted and pivot.
• Rocker Cover: Also known as a valve cover, it is the removable cover that encloses the rocker arms on top of the cylinder head.

Synonyms

• Valve rocker
• Fulcrum lever (in this specific mechanical context)

Related Phrases

• To adjust the rocker arms: This phrase describes the maintenance task of setting the correct clearance (valve lash) between the rocker arm and the valve stem.
• Broken rocker arm: A common phrase indicating a mechanical failure that causes engine misfires and loud noises.

Noun

1. a lever pivoted at the center; used especially to push a valve down in an internal-combustion engine