In this article, we will study the Definition, Types, Materials, Applications, Advantages, and Disadvantages of a Belt drive system. We have also provided a PDF for the same.
What is a belt-drive
The belt is a flexible element of a mechanical system. It is used to transfer power from one System to another. The belt drive is also known for continuous power transmission.
5 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
Open belt-drive
In this, the shafts rotate in the same direction which means the direction of rotation is the same as the driving and driven pulley. The shafts are arranged in a parallel direction. If the shafts are having a more distance between the driver and the driving pulley then there must be the upper side will be the slack side and the below side will be the tight side.
Crossed belt-drive
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 wears and tears off, and if you don’t want to wear and tear then place more distance between the pulley and run at low speed.
Fast and loose cone pulley
As the name indicates fast and loose pulley means there are two pulleys 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 the speed cone. Here in the stepped cone pulley, there are more pulleys attached of different diameters one adjacent to another. Stepped cone pulleys are used where they have to change the gear or speed of the driven shaft change frequently like a machine (Lathe, Milling, and more). 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 pulley
Jockey pulleys are used in the steering section of the system. A jockey pulley is like an idle pulley and 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. 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.
4 Types of Belt
Belt has been categorized into four types which are as follows
● Flat belt
● V belt
● Circular belt
● Timing belt
Flat Belt
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. A flat belt transmits power by using friction produced 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 into this belt.
V belt
V belts are in the trapezoidal cross-section. V belts are used where the shaft distance is less than 2 meters and are also used for moderate speed and high power. In belt the multiple drives are possible.
Circular belt
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.
Timing belt
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 posses some properties which are as follows
● It should be flexible
● It should be reliable and durable.
● The material can withstand high tensile stress.
● High-temperature resistance.
● Low weight per unit length.
● High coefficient of friction between belt and pulley.
● It should have excellent resistance to wear and fatigue.
5 different types of material we use for Belt
- Leather belt
- Rubber belt
- Cotton or Fabric belt
- Plastic belt
- Balata belt
Leather belt
- This is the most important type of belt. This belt was first found in Egypt.
- The leather belt is the one you might have seen in your daily life.
- This belt is more expensive than other belts made of cloth or recycled materials.
- To make a leather belt strong, one layer of leather is joined with 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 which are as follows
- 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
- It can be easily installed and easily removed.
- 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
- Power loss due to slip and creep.
- Not useful for a very short distance.
- Speed is limited to some extent.
- It is quieter.
- No possibility of a Longer life.
- Chances of breaking are high.
- The operation temperature is limited between -35 to 85 degrees Celsius. If it exceeds its temperature range 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
- The belt drive is used in the Mill industry.
- The belt drive is used in Conveyor.
- Power transmission in industrial machinery and equipment
- Automotive applications, in different types of engines and transmissions
- Agricultural machinery, such as tractors and harvesters
- Conveyor systems in manufacturing and distribution facilities
- HVAC systems in buildings, such as fans and air handling units
- Exercise equipment, such as treadmills and stationary bikes
- Office equipment, such as printers and copiers
- Power tools, such as table saws and drill presses.
Belt Drive vs Chain Drive
| Parameters | Belt Drive | Chain Drive |
|---|---|---|
| Design | Belt drive uses a flexible belt made of rubber, neoprene, or other materials to transmit power between the pulleys. | Chain drive uses a chain made of metal links to transmit power between the sprockets. |
| Efficiency | Belt drive has a higher efficiency compared to chain drive, due to the lower friction between the belt and the pulleys. | Chain drive has a lower efficiency compared to belt drive, due to the higher friction between the chain and the sprockets. |
| Noise | Belt drive produces less noise compared to chain drive, due to the absence of metal-to-metal contact. | Chain drive produces more noise compared to belt drive, due to the metal-to-metal contact between the chain and the sprockets. |
| Maintenance | Belt drive requires less maintenance compared to chain drive, as the belt does not require lubrication and is less prone to wear and elongation. | Chain drive requires more maintenance compared to belt drive, as the chain requires regular lubrication, tensioning, and replacement due to wear and elongation. |
| Load capacity | Belt drive has a lower load capacity compared to chain drive, as the belt can only transmit power over a limited distance and is more prone to slipping and stretching. | Chain drive has a higher load capacity compared to belt drive, as the chain can transmit power over long distances and is less prone to slipping and stretching. |
| Cost | A belt drive is generally less expensive compared to a chain drive, due to the lower cost of the belt and the simpler design. | Chain drive is generally more expensive compared to belt drive, due to the higher cost of the chain and the sprockets, and the more complex design. |
Some Formulas of Belt drive
Belt drive formulas are categorized into two parts.
- Open belt-drive
- Cross belt drive
These are some common formulas related to belt drives
- Belt Speed (V)
- V = [πDN/60]
- where V is the belt speed in m/s, D is the diameter of the pulley in meters, and N is the rotational speed of the pulley in rpm.
- Center Distance (C)
- C = {(D1 + D2)/2 + (L2 – (D2 – D1)2/4)0.5}
- where D1 and D2 are the diameters of the driver and driven pulleys respectively, and L is the distance between the centers of the pulleys.
- Belt Length (L)
- L = {2C +[ (D2 – D1)2/4*C]}
- where C is the center distance between the pulleys, D1 and D2 are the diameters of the driver and driven pulleys respectively.
- Tension Ratio (T2/T1)
- T2/T1 = e(μθ),
- where μ is the coefficient of friction between the belt and the pulleys, and θ is the angle of wrap of the belt around the smaller pulley.
- Power Transmission (P)
- P = [T1*V/1000]
- where P is the power transmitted in kW, T1 is the tension in the tight side of the belt in N, and V is the belt speed in m/s.
- Belt Tension (T)
- T = (P*1000)/(Vefficiency)
- where T is the belt tension in N, P is the power transmitted in kW, V is the belt speed in m/s, and efficiency is the efficiency of the belt drive.
Slip and Creep in Belt
Slip
A firm frictional grip between the 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.
Creep
When the belt passes from the slack side to the tight side, a certain portion of the belt extends and when the belt passes from the tight side to the 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.
| Parameters | Slip | Creep |
|---|---|---|
| Definition | Slip refers to the relative motion between the belt and the pulley due to insufficient tension or excessive load. | Creep refers to the relative motion between the belt and the pulley due to the difference in the circumferential speeds of the two pulleys. |
| Cause | Slip is caused by insufficient tension, excessive load, or worn-out belts. | Creep is caused by the difference in circumferential speeds of the pulleys, which occurs when the belt is not perfectly flexible or there is a difference in the diameters of the pulleys. |
| Effects | Slip results in a loss of power transmission, increased wear of the belt and pulleys, and reduced efficiency of the drive. | Creep results in an uneven distribution of tension across the belt, which can cause increased wear and fatigue of the belt. |
| Types | There are two types of slip: forward slip and backward slip. | There are two types of creep: positive creep and negative creep, |
| Prevention | Slip can be prevented by maintaining proper tension, avoiding overloading, and using high-quality belts. | Creep can be minimized by using properly designed pulleys, avoiding excessive belt tension, and selecting belts with high flexibility. |
| Measurement | Slip is measured as the percentage of the difference between the belt speed and the pulley speed. | Creep is measured as the percentage of the difference between the tension in the tight side and the tension in the slack side of the belt. |
FAQ
What Are The Types Of Belt Drives?
- Open belt-drive
- Closed or crossed belt-drive
- Fast and loose cone pulley
- Stepped cone pulley
- Jockey pulley drive
What Are The Advantages Of A Belt Drive?
- 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 vertically, horizontally, and inclined too.
- Power consumption is low.
Comparison between belt drive vs hub motor
The decision between belt-drive and hub motor can have a significant impact on the performance and maintenance of electric bikes. While belt drives are recognized for their low maintenance and noiseless operation, hub motors deliver greater power and torque. Ultimately, the rider’s requirements and preferences determine the suitable option.
what is the price and purpose of belt drive oil pump
Belt-drive oil pumps are used to circulate oil throughout an engine’s various components, such as bearings and pistons. The cost of a belt-drive oil pump can vary depending on the manufacturer and specific model but generally ranges from a few hundred to a few thousand dollars. The purpose of a belt drive oil pump is to ensure proper lubrication and cooling of the engine, thereby reducing wear and tear and prolonging the engine’s lifespan.
What is the price and purpose of belt drive Vacuum pump
Belt-drive vacuum pumps are used to remove air or gas from a sealed chamber or container. The cost of a belt drive vacuum pump can vary widely based on the manufacturer, model, and application, ranging from a few hundred to thousands of dollars. The purpose of a belt-drive vacuum pump is to create a vacuum for various industrial applications, such as in the manufacturing of semiconductors, vacuum tubes, and fluorescent bulbs.
Belt Drive products used in our daily lives
- Belt Drive Pressure washer
- Belt Drive Electric skateboard
- Belt Drive Garage Door opener
- Belt Drive Motorcycles
Conclusion
In conclusion, belt drives are a popular type of power transmission system that has a wide range of applications across various industries. They are available in different types and materials to suit specific requirements, and their advantages include efficient power transmission, smooth operation, and low maintenance.
However, belt drives also have some disadvantages, including belt slip, high noise levels, and limited load capacity. Therefore, it is important to carefully consider the application and requirements before selecting a belt drive system.
References
