What is Belt Drive? Advantages and disadvantages of belt drives
Belt drives, one of the most popular mechanical drive mechanisms, play an important role in many industries due to their simplicity, efficiency, and low cost. This article will help you better understand what a belt drive is, its structure and operating principle, common types of belt drives, as well as its advantages and disadvantages and applications in conveyor systems. Through this, businesses can select and use the belt drive system in the most effective way to optimize the production process.
1. What is belt drive?
Belt drives are drive mechanisms that use elastic belts and pulleys to transmit rotational motion from the drive shaft to the led shaft. This drive system works on the principle of friction between the belt and the wheel, which makes the rotational movement from the motor to the consuming device efficient. Belt drives are widely used in industries due to their simplicity, efficiency, and low cost.
2. Structure and principle of operation
The belt drive mechanism consists of three main parts: the belt (belt), the belt wheel (pulley), and the spindle.
- Belt (belt): Belt drive is usually made from materials such as rubber, fabric, or composite to ensure high strength and friction, being the most important part, be it a plain belt, a tooth belt, or a mesh belt.
- Pulleys: Contain grooves for the belt to run through, usually made of steel, aluminum, or heavy-duty plastic.
- Shaft: Where the pulleys are attached, which helps the belt to move in the direction of rotation of the pulley.
Operating Principle:
When the drive shaft rotates, the belt is pulled and the motion is transmitted to the pulley on the led shaft. Due to the frictional force between the belt and the pulley, the led shaft will also rotate. The drive ratio is determined by the ratio of the diameter of the drive pulley and the led pulley.
3. Types of belt drives today
Currently, there are many types of belt drives used in industry, each suitable for different applications and operating conditions such as:
3.1. Open Belt Drive
Open belt drives are used when the shafts are arranged in parallel and rotate in the same direction. In this configuration, the pulley actively pulls the belt from one side and transfers it to the other, resulting in higher tension in the lower belt section than in the upper belt section. The lower part of the belt is called the tension belt, while the upper part of the belt is called the slack belt.
When the axes are excessively far apart, the underside of the belt should be the tension side and the top side should be the slack side. During operation, the upper surface will expand due to its own weight, thereby increasing the contact arc.
3.2. Closed or Crossed Belt Drive
Cross belt drives, also known as helical belts, are used when the axes rotate in parallel but opposite directions. Similar to an open-belt actuator, the pulley actively pulls the belt from one side and moves it to the other. In this case, the upper belt is also the sagging belt, and the lower belt is the tension belt.
This type of drive uses a single belt when two parallel axes rotate in opposite directions. At the junction of the belt, it rubs against itself and wears out. To avoid excessive wear, the shafts should be kept at maximum distance and operated at low speeds. The distance between the axes should be a maximum of 20 times the width of the belt, and the belt speed should not exceed 15 m/s.
3.3. Puli động (Fast And Loose Cone Pulley)
This type of belt drive is used when the drive shaft needs to be started or stopped without affecting the main machine shaft. A pulley is locked to the machine shaft, called a fast pulley, which runs at the same speed as the machine shaft. A loose pulley runs freely on the machine shaft without transmitting power. When the drive shaft needs to be stopped, the belt is pushed onto the loose pulley thanks to a slider with belt discs.
3.4. Stepped Cone Pulley Drive
The speed step drive is used to change the speed of the drive shaft, while the spindle moves at a constant speed. This is done by transferring the belt from one speed stage to another.
A speed step pulley is an integration of three or more pulleys of different sizes, located next to each other. A set of drive speed step pulleys is placed upside down on the drive shaft, and the drive belt is wound around a pair of pulleys. By transferring the belt from one pair of pulleys to another, the speed of the drive shaft can be changed.
3.5. Belt Tension Actuator (Jockey Pulley Drive)
In the open belt drive arrangement, if the distance between the shafts is small or the drive pulley is too small, the contact arc of the belt with the pulley will be very small, reducing the tension of the belt. To overcome this, a free pulley, called a carriage pulley, can be added, which is placed on the slack side of the belt. This increases the contact surface and tension, which increases the drive.
3.6. Quarter Turn Belt Drive
Perpendicular belt drives, also known as right-angle belt drives, are used when the shafts are arranged at right angles and rotate in a certain direction. In order for the belt not to leave the pulley, the width of the pulley face must be greater than or equal to 1.4 times the width of the belt. If the pulley cannot be arranged or when the rotation speed needs to be changed, a belt drive perpendicular to the guide pulley can be used.
3.7. Compound Belt Drive
Complex belt drives are used when it is necessary to transfer power from one shaft to another through multiple intermediate shafts. This system allows for flexible and efficient power transmission, making it suitable for applications that require multi-point and complex drives.
4. Factors to keep in mind when using a wire belt drive
Different from chain drives, when using belt drives, in order for them to work effectively, the following factors should be noted:
4.1. Shaft Installation
The installation of the shaft needs to ensure that the shaft is in the correct position, not misaligned, and that the tension of the belt is sufficient for effective transmission but not over-tensioned causing belt damage.
4.2. Pulley Installation
The pulley needs to be installed so that the grooves of the belt wheel fully match the belt. Precise installation minimizes wear and increases the life of the drivetrain.
4.3. Notes and strap lengths
The belt length needs to be calculated correctly to ensure the drive efficiency. Belts that are too long or too short can cause problems with the performance and longevity of the system.
4.4. Routine maintenance
Routine maintenance is critical to maintaining the efficiency of the belt drive system. Maintenance activities include belt tension checks, lubrication, and checking for signs of wear or failure for timely replacement.
5. Classification of belt drives
Based on the load and belt speed, belt drive is classified into three main groups as follows:
5.1. Light transmission
Lightweight drives are often used in office equipment, small machinery, or systems that do not require high transmission forces. Flat belts are the type of belts that are commonly used in these applications.
5.2. Average Transmission
Medium drives are used in industrial equipment such as pumps, industrial fans, and manufacturing machinery. Ladder belts and tooth belts are commonly used for these applications thanks to their good power transmission and high strength.
5.3. Heavy Transmission
Heavy duty drives are applied in systems that require very large transmission forces such as industrial conveyors, crushers, and construction equipment. Specialized belts with high load capacity are used to ensure efficiency and durability.
6. Belt drive applications in conveyor systems
Conveyor drive systems are typically installed at critical intersections such as tripping points and locations between the tail and the head of the conveyor. A conveyor drive system typically consists of the following components: bearings, motors, actuators, shafts, couplings, bushings, guards, and gears. Belt drives and conveyor drive pulleys play an integral role in the drive from the motor to other parts such as shafts and rollers.
Belt drives play an important role in conveyor systems, helping to transmit movement from the motor to other parts efficiently, smoothly and safely. Here are the main applications of belt actuators in conveyor systems:
- Motor-to-spindle drive: This is the most common application of belt actuators in conveyor systems. The motor transmits power through belts and pulleys to the spindle, which helps the spindle rotate and generate traction for the conveyor. As a result, the conveyor belt can move the material continuously and stably.
- Transmission for auxiliary parts: In addition to driving for the spindle, belt actuators are also used to drive other auxiliary parts in conveyor systems such as drive rollers and belt tensioners. These parts help to maintain the correct tension and tension of the belt, ensuring the smooth and efficient operation of the system.
Thanks to these applications, belt drives help to optimize the operation of conveyor systems, minimize wear and failure, and enhance the durability and performance of the system.
7. Conclusion
Above is an overview of belt drive and its advantages and disadvantages. Hopefully, this information will help you have a better view of the type of belt drive mechanism and its effective application in production operations.
In addition, to support businesses to update new trends in the manufacturing industry and supporting industries, RX Tradex organizes a series of prestigious international exhibitions this year, including NEPCON Vietnam, METALEX Vietnam, Vietnam Manufacturing Expo and Waste and Recycling Vietnam. These events will provide a great opportunity for businesses to explore advanced technology solutions, meet potential partners and expand their business networks, helping businesses access the latest trends and technologies, thereby improving production processes and improving competitiveness in the market.
