25-08-2017, 09:32 PM
Study of gears
gears.ppt (Size: 1.65 MB / Downloads: 74)
objectives
Students will be able to know
Concept of gears
Types of Gears
Concept of Gear Train
Types of Gear trains
Introduction to gears
Slipping of belt or rope is the problem
Constant velocity ratio is needed in power transmission
Gear is a component within a transmission device that transmits rotational force to another gear or device.
Gear drive transmits exact velocity ratio
Also used when centre distance is small
It has high efficiency
It has compact layout
Used in automobiles and machines for power transmission
Types of Gears
According to position of axis of shaft
Spur gear
Helical gear
Rack and pinion gear
Bevel gear
Worm and worm gear
helical gear
Teeths are inclined to the axis of wheel
Are used in transmitting torques between parallel or non parallel shafts, they are not as noisy as spur gears
bevel gear
Teeth are formed on conical surfaces, the teeth could be straight or spiral
Are used to transmit rotary motion between intersecting shafts
Rack &pinion gear
Teeths on a rack gear are straight
Small diameter gear is called pinion
Used to convert linear motion in to rotary or v/c.
Worm &worm gear
Are used for transmitting motion between non parallel and non transmitting shafts,
Depending on the number of teeth engaged called single or double.
Gear Train.
Combination of two or more gears when they made to mesh each other to transmit power from one shaft to another.
Summary
Gears are used to transmits constant velocity ratio in power transmission
Types of gears are spur, helical, rack and pinion, bevel, Worm and worm gear
Use of no. of gears for power transmission is called Gear train
Types of gear trains are simple, compound, riverted and epicyclic gear train