Common Machine Components + Typical Part Features

Bearings

Facilitate rotational or sliding motion between parts by reducing friction and providing mechanical support

Sleeve bearing (bushing)

Ball bearing

Thrust bearing

Linear bearing

Pillow block

Belt drives

Transfer power from one shaft to another using a flexible belt and pulleys

V-belt

Ribbed v-belt

Pulley (or sheave)

Timing belt

Timing belt pulley (sprocket)

Cams

Non-circular components of a rotating shaft used to produce variable or reciprocating motion of another part (the ___ follower)

Cam

Roller chain

Sprocket

Toothed wheel that engages with a chain or belt to transmit power between rotating shafts (like a gear but meshes w/ chains, not other gears)

Clevis (w/ male threads)

Securely connects mechanical parts while allowing for a specific range of motion, typically rotational, between them

Clevis (with female threads and pin)

Collars

Constrain a shaft, or parts on a shaft, from axial motion

Set Screw Collar

One-Piece Clamp-On

Two-Piece Clamp-On

Couplings

Join the ends of two shafts together such that they rotate at the same speed and transmit the same amount of torque

Rigid coupling

Flexible coupling

Flexible coupling (with a spider)

Drive shaft

Gears

Transfer mechanical power between two shafts through a change in torque, rotational speed, and/or direction

Spur gear

Compound gear

Keyway

A shaped depression cut along the axis of a cylinder or hub used to receive a key, attach hubs, gears, and other parts to a cylinder so they will not turn on it

Bevel gear

Differential gear

Helical gear

Helical bevel gear

Worm gear and worm

Gear box

Modifies the engine's torque and speed to suit different driving conditions

Gear head

Often referred to as gear reducers because they increase torque output while decreasing motor rpm and improve control over speed and position

Rack and Pinion

Converts rotational motion into linear motion, (commonly seen in car steering systems translating the steering wheel's circular motion into the side-to-side movement of the wheels); also used in linear actuators

Planetary gear drive

Increase or decrease both speed and torque in a small, compact space (sun gear is input and driving gear)

Keys

Transmit torque from a rotating shaft to a shaft component (e.g. gear, pulley).

Square key

Woodruff key

Key seat

The groove or pocket on a shaft

Pulley

Rod end with male threads

Snap rings/retaining rings

Constrain components from sliding axially along a shaft

External snap ring

Internal snap ring

External E-style snap ring

Compression spring

Extension springs

Torsional spring

Spiral spring

Universal joints

Transmit torque and rotational motion between two non-colinear shafts

Fillet

Rounded interior blend between surfaces; used to reduce stress at corners and/or allow a part to be removed from a mold

Countersink

Cone shaped recess around a hole, often used to receive a tapered screw head

Boss

Short raised protrusion above the surface of a part, often used to provide a strong flat bearing surface

Round

A rounded exterior blend between surfaces: used to make edges and corners easier to handle, improve strength of castings, and allow for removal from mold

Counterbore

Cylindrical recess around a hole, usually to receive a bolt head or nut

Lug

Flat or rounded tab protruding from a surface, usually to provide a method for attachment

Bushing

Hollow cylinder that is often used as a protective sleeve or guide, or as a bearing

Chamfer

Angled surface, used on cylinders to make them easier to insert into a hole, or plates to make them easier to handle

Spotface

Shallow recess like a counterbore, used to provide a good bearing surface for a fastener.

Flange

Flattened collar or rim around a cylindrical part to allow for attachment.

Knurl

Pattern form on a surface to provide for better gripping or more surface area for attachment, often used on knobs and tool handles