Belt drives are one type of frictional drive that used for transmitting the powers by looping the belt over the pulleys, linking two or more rotating shafts at the designed speed. The construction and installation of the belt drive are relatively simple and it can be removed easily in the engineering system. It can transfer the power vertically, horizontally, or in inclined too at low power consumption. Belt drives are the popular mechanical component to be applied in various industry such as mill factory, it is used in a conveyor system, motor/fan system, or used in the automobile to transfer the power to a various component such as air-conditioning, alternator, etc. Here we will introduce a few common types of belts and belt drives used in the engineering system.
The belt is the friction drive which depends on the friction between the pulley and belt to transmit the power. The part of the belt having less tension we usually called it slack side, and another part which is having higher tension we called it tight side. The angle of the contact will decide the tensions in the slack side and tight side. The system designer will choose the right belt based on the power to be transmitted, the transmission ratio, and center distance. The belt can be made of a variety of materials such as leather, rubber, plastic, cotton/fabric, or balata belt. There are mainly four common types of belts available in the industry which including flat belt, V-belt, round belt, and timing/toothed belt.
1. Flat belt is a rectangular cross-section. It is designed for high performance conveying and light-duty power transmission, not suitable for transferring the power at a relatively small distance. It transmits the power by using friction created between the pulley and belt. The distance between shafts will normally be maintained at around 5 to 10 meters. Flat belts can come in both endless and jointed construction designs and normally made of leather, rubber, or synthetic polymers. Traditionally, the problem of high tension and mistracking happened on the flat belt. But due to the latest design and technology, the advances in the material have made low and high power transmission both practical and cost-efficient. The flat belt has an efficiency of nearly 98% and it creates only little noise.
2. V-Belt is the most widely used type in the industry now due to its relatively low cost, variety of sizes, and ease of installation. It has replaced the flat belt for short-distance power transmission where the distance between shafts will not greater than 2 meters. V-belt is suitable to operate at a moderate speed and high power transmission. It has a v-shaped cross-section which can help to prevent the belt from slipping off and diminish the alignment problem. The v shape design also makes it easy to keep a fast-moving belt in sheave grooves on a pulley than the flat belt. This type of belt allows a large speed ratio and able to transmit higher power.
3. Round Belt has a circular cross-section and made of rubber. It is normally used in round groove pulley and for the light loading purposes such as vacuum cleaner or sewing machine. The disadvantage is it has a higher chance of slippage.
4.Timing/Toothed belt is having a teeth design that can fit into the toothed pulley and use it to transmit the power which is as opposed to the friction. There will be no slippage with the use of toothed belts. It can also reduce noise and has high mechanical efficiency of around 98%. However, it will be more expensive to produce due to its complex design and pulley shapes.
There are different types of belt drives for different purposes. In choosing the right type of belt drive, we need to consider several factors such as the distance between shaft and pulley, the required speed of the driver and driven pulley, the power to be transmitted, and the designed layout of the shafts and others.
Open belt drive
In an open belt drive, the pulley and belts are arranged in a way driver and the driven pulley rotates in the same direction. The shafts are arranged in a parallel direction for an open belt drive. If the distance between the driver and driving pulley is long, then the upper side will be the slack side and the lower side will be the tight side.
Cross belt drive
In a cross belt drive, the belt is arranged in a way the drive and driven shaft rotates in an opposite direction. Cross belt drive can transmit more power but it can not run at a faster speed as it will create more rubbing between the belts. In order to prevent wearing/tearing from rubbing, we need to run it at a low speed and create more distance between the pulleys.
Stepped cone pulley or speed cone drive
It consists of steps in the pulley and there are more pulleys with several diameters mounted on the parallel shafts to engage the transmission and provide different speed ratios. It is available in 2-step, 3-step, and 4-step styles, we can shift to another pulley and the same belt will still operate. A stepped cone pulley is used when the gear or speed of the driven shaft requires changes frequently such as the lathe machine, milling machine, and more. The diam
Fast and loose pulley drive
Fast and loose pulley drive is used when the driven shaft requires to stop or start very quickly. It has consisted of two pulleys known as the fast and free pulley. The fast pulley connects to the machine shaft with keyed joint and the free pulley rotates freely on the machine shaft. The free pulley is not transmitting any power.
Jockey pulley drive
A jockey pulley drive is a small pulley that is placed on the slack side of the belt and like an idle pulley that is used for increasing the angle of contact of the belt. It is used when the distance between the two shafts is relatively small. Jockey pulley drive is used in the steering part of the system.
MecHero Malaysia offers a wide range of belts and belt drives for multiple applications in Malaysia. You can always contact us at +6011-7000 7687 or email us at my.mechero@gmail.com for the inquiry about the mechanical components or engineering products. Tell us your requirements now and we can advise you accordingly.
Photo credit: gobdp, smlease, medium, amazon, riansclub, directindustry, ibtinc