## BASICS OF MECHANICS

TYPES OF GEARS :

Everyone who want to begin their career in robotics must have grip on 3 parts of engineering

•         Mechanics
•          Electronics
•        Programming.

In this article I am going to share you basics of mechanics on types of gears which is essential for a beginner in robotics.

Gears are the essential things in a mechanical part for the transmission of motion .

Gears are wheel-like machine elements that have teeth uniformly spaced

around the outer surface. They are used in pairs and are a very valuable

design tool.

What is a gear?

A gear is a toothed cylindrical or roller shape component of a machine which meshes with another toothed cylindrical to transmit power from one shaft to another. It is mainly used to change in torque and speed of driving shaft and driven shaft.

According to the type of gearing. The gears, according to the type of gearing, may be

classified as :

(a)   External gearing, (b) Internal gearing, and (c) Rack and pinion.

Let us see each of them briefly

External gearing

In simple language we can say that gears having teeth over its outer side of the body as shown in figure below; the gears of the two shafts mesh externally with each other.

Internal gearing:

In simple language we can say that gears having teeth over its inner side of the body as shown in figure below; the gears of the two shafts mesh internally with each other.

Rack and pinion:

Rack is a gear of infinite radius . The smallest of the mating gear is known as pinion.

It is used to convert the linear motion to rotatory or vice versa.

Lets see the real life pictures of the above types:

Some basic terms used in gears:

1.      Pitch circle: It is an imaginary circle which by pure rolling action, would give the same motion as the actual gear.

2.      Addendum: It is the radial distance of a tooth from the pitch circle to the top of the  tooth.

3.      Dedundum: It is the radial distance of a tooth from the pitch circle to the bottom of the  tooth.

BASIC FORMULA FOR THE CALCULATION OF SPEED OF GEARS FROM TOOTH RATIO AND VICE VERSA

T1=number of teeth on 1st gear

T2=number of teeth on 2nd gear

V1=speed of the 1stgear

V2=speed of the 2ndgear

T1*V1=T2*V2

This is simply derived by relation that speed of gear is inversely proportional to the no. of teeth present on it.

LET US DISCUSS SOME OF THE IMPORTANT GEARS USED IN THE MECHANICAL PARTS OF THE ROBOTS

•       Spur gear:
Spur gears are the most commonly used gears due to their simplicity and the fact that they have the highest possible efficiency of all gear types. They cannot withstand higher loads.
• Double helical gear:
A Herringbone gear, also known as a Double helical gear is a special type of gear which is a side to side combination of two helical gears of opposite hands

•       Bevel gear:

Bevel Gears are used exclusively to transmit rotary motion between intersecting shafts. Through commonly seen in right angle drives, bevel gears can be cut to drive any angle.

•      Crown gear:

A crown gear is a gear which has teeth that project at right angles to the face of the wheel.

• Worm gear:
Worm gears resemble screws. A worm gear is usually meshed with a spur gear or a helical gear, which is called the gear, wheel, or worm wheel. It is the best gear to attain high torque and low speed.  It also acts as a brake to reverse spin.

WORM GEAR IN REAL LIFE APPLICATION

• Rack and Pinion:

Rack is a gear of infinite radius .The smallest of the mating gear is known as pinion.

FINAL NOTE:

This was very basic introduction about gears used in robots and in next articles i will deal about more mechanical, electronic and programming parts of the robots.

Have fun with the content and feel free to ask any doubts.