MACHINE DESIGN ELEMENTS 08

An imaginary circle passing through the points at which the teeth of the meshing gears contact each other.

• pitch circle

• addendum circle

• dedendum circle

• base circle

The number of teeth per inch. of pitch diameter and which gives some indications of the size of the gear teeth.

• module

• pitch circle

• diametral pitch

• circular pitch

The distance from the center of one tooth of a gear to the center of the next consecutive tooth measured on the pitch.

• circular pitch

• module

• diametral pitch

• pitch circle

The portion of a gear tooth that projects above or outside the pitch circle.

• top relief

• dedendum

• addendum

• tooth space

The portion of the gear tooth space that is cut below the pitch circle and is equal to the addendum plus the clearance.

• top root

• dedendum

• addendum

• top land

A kind of gear used for heavy duty works where a large ratio of speed is required and are extensively used in speed reducers.

• bevel gears

• worm gears

• helical gears

• spiral gears

A kind of gear used to transmit motion from one shaft to another shaft at an angle to the first.

• bevel gears

• worm gears

• helical gears

• spiral gears

The clearance between the tooth profiles of a gear tooth.

• toothspace

• backlash

• flank

• width

Addendum of a cycloidal gear tooth is

• cycloid

• epicycloid

• straigth rack

• involute

The train value of gear train is

• equal to the speed ratio

• double the speed ratio

• half of the speed ratio

• reciprocal of the speed ratio