The belt drive is also known as for continuous power transmission.
In today’s article, we will study Definition, Types, Material, Applications, Advantages, Disadvantages of Belt drive.
What is a belt-drive?
The belt is a flexible element of a mechanical system. It is used to transfer the power from one System to another System.
Types of Belt-Drive:
There are five different kinds of belt drive can be found and those are:
- Open belt drive
- Closed or crossed belt drive
- Fast and loose cone pulley
- Stepped cone pulley
- Jockey pulley drive
In this, the shafts rotate in the same direction that means the direction of rotating is the same as driving and driven pulley.
The shafts are arranged in the parallel direction.
If the shafts are having a more distance between driver and driving pulley then there must be the upper side will be slack side and the below side will be the tight side.
Here in the crossed belt drive the transmitted power is more but there is a problem that it can not run faster. If so then rubbing between belts may wear and tear.
In this, the shafts rotate in the opposite direction. At the junction side, it rubs and therefore it wears and tears off.
And if you don’t want to wear and tear then place more distance between pulley and run at low speed.
Fast and loose cone pulley:
As the name indicates fast and loose pulley it means there are two pulleys in it.
How are these two pulleys placed in it?
The fast pulley is mounted on a shaft with keyed joint and the loose pulley runs freely on the shaft and it is incapable of transmitting any power.
Another term in that is when multiple machines are working from a single power source then in this condition, each machine has provided with this fast and loose cone pulley.
Stepped cone pulley:
This is also known as speed cone.
Here in stepped cone pulley, there are more pulleys attached of different diameter one adjacent to another.
The diameter of the driving and driven pulley is such that when we wanted to shift to another pulley the same belt will operate.
Jockey pulleys are used in the steering section of the system.
Jockey pulley is like an idle pulley and which is used for increasing the angle of contact in an open belt drive.
Hence increasing the angle of contact steer to the increased power transmission capacity of the drive.
This one pulley is mounted nearer to the smaller pulley and we can say also this is placed on the slack side of the belt.
Let’s understand jockey pulley in detail:
It (jockey or idle pulley) helps to increase the angle of contact of the belt, so that belt tension is increased and also the drive provides a high-velocity ratio.
Types of Belt:
Belt has been categorized into four types which are:
● Flat belt
● V belt and
● Circular belt
● Timing belt
Let’s study these four belts in detail.
This is a kind of rectangular cross-section.
It is used where low power is required and speed is more. Generally, the shaft distance is between 5 to 10 meters.
Flat belt transmits power by using friction produce between the belt and the pulley.
The pulley rotation in the flat belt is in the same direction.
The flat belt has an efficiency of around 98 percent
Very little noise comes in this belt.
V belts are in the trapezoidal cross-section.
V belts are used where shaft distance is less than 2 meters and also used for moderate speed and high power.
In belt the multiple drives are possible.
It is a circular cross-section.
Circular belts are used where more than a 5-meter shaft distance.
It is used for high power transmission.
Circular belts are also used where smaller initial tension is required and absences of vibration and noise are there.
This is an alternate type of belt.
Timing belts are mainly used inside (internal combustion type) the system to transmit power.
Timing belts are a positive drive.
It is a precise and reliable type of belt.
Materials used in Belt:
For choosing belt material, the material should follow some properties which are:
● It should be flexible
● It should be reliable and durable.
● The material can withstand high tensile stress.
● More temperature can be resisted.
● Low weight per unit length.
● High coefficient of friction between belt and pulley.
● It should have excellent resistance to wear and fatigue.
There are 5 different types of material we use for Belt:
- Leather belt
- Rubber belt
- Cotton or Fabric belt
- Plastic belt
- Balata belt
Let’s study these 5 different types of belt material in detail.
● Leather belt:
This is the most important type of belt.
This belt is first found in Egypt.
The leather belt you might have seen in your daily life. Yes? Yes, it is.
This belt is more expensive than other belts made of cloth or recycled materials.
And you know, to become a leather belt strong, the one layer of leather is joint to another layer to become stronger and increase the thickness of the belt.
● Rubber belt:
- This belt is made up of fabric.
- This is used in sawmills, paper mills and more.
● Cotton or Fabric belt:
- This type is mostly used in farm machinery and belt conveyor.
- This is cheaper and best suited for warm climates and a damp atmosphere.
● Plastic belt:
- These types of belt materials are made up of plastic sheets and rubber layers.
- The main advantages of a plastic belt are that it can design almost any size.
● Balata belt:
- Balata belts are similar to rubber type belts but this is stronger than rubber belt.
- The balata gum is used here to stick it.
- It is a Waterproof type belt and has a high resistance to acidic, alkaline material so this is used for food packaging conveyor.
- This is not used for high temperatures because balata becomes sticky gum at a higher temperature.
Selection of Belt-drive:
The selection of belt drive depends on several factors. Some of them I am listed out here:
- It requires a positive drive.
- The center distance between the shaft and pulley.
- The speed of the driver and driven pulley.
- Power transmitted between the system.
- The layout of shafts and others.
Advantages of Belt-drive:
A belt-drive has following advantages:
- It can easily install and easily remove.
- The price of the belt drive is low.
- Simple in construction.
- The maintenance cost is low.
- No additional lubricant is required.
- It can transfer power vertical, horizontal and inclined too.
- Power consumption is low.
Disadvantages of Belt-drive:
Also, there are some disadvantages of belt drive and those are:
- Power loss due to slip and creep.
- Not used for a very short distance.
- And speed is limited to some extent.
- It is quieter.
- Longer life is not possible.
- Chances of breaking are more.
- The operation temperature is limited between -35 to 85 degrees Celsius. If it exceeds temperature then it causes wear.
- Angular velocity ratio is not necessarily constant or equal to the ratio of pulley’s diameter because of slipping.
Applications of Belt-drive:
Belt-drives are used in various places like:
- A belt drive is used to transfer power.
- The belt drive is used in the Mill industry.
- The belt drive is used in Conveyor.
Belt Drive vs Chain Drive:
|Belt Drive||Chain Drive|
|Belt drive is used for transferring the power.||The chain drive is also used for transferring power.|
|The belt drive is powered by only a belt.||The chain drive is powered by a chain loop.|
|Belt drives are made up of synthetic material. This is not stronger as compared to the belt drive.||Chain drives are made up of metal which is stronger and more durable.|
|Belt drives are used in mills.||The chain drive is used in bicycles, motorcycles, and many more engines.|
|In belt drive, little difficulties have when it gets damaged.||It is easier to change or fix when its get damage|
|Low or medium in price||Price is high|
|The belt drive is not the lubricating system||The chain drive is a lubricating system.|
|The belt drive is quieter than the chain drive.||The chain drive is not quittered than a belt drive.|
Some Formulas of Belt drive:
Belt drive formulas are categorized in two parts of the belt.
- Open belt drive
- Crossbelt drive
Slip and Creep in Belt:
A firm frictional grip between belt and shaft is essential.
But sometimes it becomes insufficient.
This may cause some forward motion of the belt without carrying the driven pulley with it. This is called a slip of the belt.
Slip is expressed in percentage.
When the belt passes from slack side to tight side, a certain portion of the belt extends and when the belt passes from tight sight to slack side it contacts.
Due to these changes in length, there is a relative motion between the belt and the pulley surfaces. This relative motion is called creep.
Difference between slip and creep:
Creep is due to the elastic property of the belt whereas, the conventional slip is due to insufficient frictional grip between the belt and pulley.
However, the effect of the creep, as well as slip, is to reduce the speed ratio, and hence power transmission.
So, readers, this is all about the Belt-drive I hope you got the general concept of belt drive, do not hesitate to tell your doubts in the comment section and also do share your feedback on this article.
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What are the types of belt drives?
1. Open belt drive
2. Closed or crossed belt drive
3. Fast and loose cone pulley
4. Stepped cone pulley
5. Jockey pulley drive
What are the advantages of a belt drive?
1. It can easily install and easily remove.
2. The price of the belt drive is low.
3. Simple in construction.
4. The maintenance cost is low.
5. No additional lubricant is required.
6. It can transfer power vertical, horizontal and inclined too.
7. Power consumption is low.