Timing Gear – Timing gears, since the name implies, are utilized for various timing reasons. Also called synchronous gears, they could be either spur or helical gears. They are generally found in automotive applications to regulate valve timing in engines.
Worm Gear – A worm gear includes a worm and a worm wheel operating with each other. The worm resembles a screw and is sometimes called a worm screw, while the worm wheel looks comparable to a spur gear or helical gear with a slight helix angle. This set is sometimes also called a worm drive. Worm gears will be the most compact type of gear and so are often found in applications where space is limited.
Spur Gear – Spur gears are the most typical type of gear. They are accustomed to transmit motion between two parallel shafts and are known for being highly efficient and generating a whole lot of power. Spur gears are known by several other names including straight gears, straight-cut gears, spur wheels, and spur gearing. These all 
have the same simple definition and can be utilized interchangeably.
Pump Equipment – A pump gear may be the name pertaining to a gear used in gear pumps. They consist of both a driver and driven gear and can end up being either spur or helical gears. Never to be confused, the word gear pump refers to the whole pump, while pump gears identifies the gears only. Gear pumps are positive displacement pumps, meaning they pump a constant amount of liquid in each revolution. The volume of fluid in a revolution depends upon the geometry of the pump gears (i.e. number of teeth, diametrical pitch, etc.).
Spline – Splines are the ridges or tooth (external spline) on a drive shaft that mesh with an equal number of like ridges or tooth (internal spline) in a mating piece with the purpose of transferring torque from one member to the various other. The most typical splines are parallel key splines, involute splines (carefully linked to involute gears but with shorter teeth, root to suggestion), and serrations. Splines can be made by shaping, hobbing or broaching.
Sprocket – Sprockets, or sprocket wheels, are toothed tires whose tooth engage the links of chains or belts. Sprockets are distinguished from gears in that sprockets are never meshed together directly. There are several different types of sprockets, including silent chain, roller, and ladder sprockets.
Ground Helical Gear Racks pinion Gear – A pinion may be the smaller sized of two meshed gears within an assembly. Pinions gears could be either spur or helical type gears, and be either the driving or driven gear, based on the application form. Pinion gears are found in many types of gearing systems such as ring and pinion or rack and pinion systems.