Chain drive and belt drive are two mechanisms used in power transmission. The power output from an engine in the form of torque delivered by the crankshaft or axle is transferred to another rotating body such as an axle or a wheel using closed loop of chain or belt. It is one of the most common methods of power transmission.
More about Chain Drive
In most of the chain driven mechanisms, the power is conveyed using a roller chain made of metal links passing over a sprocket gear. The tooth of the gear fits into holes in the links of the chain. When the gear turns from the power of the engine or motor, the chain also moves the driven wheel at the other end. Chain drives are used in motor bicycles, bicycles and other types of automobiles.
Power transmission chains can be categorized as roller chain, engineering steel chain, silent chain, detachable chain, and offset sidebar chain. Chain drives are advantageous in applications for following reasons. Chain drives have no slippage between the sprocket teeth and chain and the stretch of the chain is minimal with a high degree of flexure. Therefore, chain drives can be used for drive mechanism operating at high load conditions.
The life expectancy of the chain drives is also higher due to material properties (suitable alloys) and the ability to use lubrication (such as oil or grease). Chain drives can be used in extreme situations and harsh environments where other systems may fail. Metal structure gives it the ability to withstand higher temperatures and moist conditions. It is not affected by the presence of dirt, mud, or other contaminants in the system; hence reliable.
On the perspective of maintenance, components of the chain drives that require very crude servicing can be replaced and serviced without disassembling other components.
The disadvantages of chain drives are excluding them from precise operation mechanisms. Chain drives produce large amounts of noise (but silent chains produce lesser noise). Sprockets elongate and deform as a result of wearing of the link and sprocket contact surface. Flexibility of the chain is limited only to one plain, and it can only be used in relatively low speed machines.
More about Belt Drive
A loop that is made out of flexible material and used for the purpose of power transmission is usually known as a belt drive. Belts can also be used for tracking relative motion and as a source of motion (conveyor belts).
Operation of a belt mechanism involves two or more pulleys where the belt is wrapped around them tautly and the pulleys are connected to the driving and driven mechanism. Due to the flexible nature of the belt’s material, pulleys can be arranged to rotate in different planes and rotate in opposite directions.
Belt drives have become the ideal choice for power transmission mechanisms due to following advantages. Power transmission belts are not lubricated and maintenance is minimal. It has a higher tensile strength and can withstand sudden changes in the load and dams the vibrations. Operation is smooth and silent. Pulleys are less expensive to manufacture than the sprocket gears, hence cheaper.
Even though belt drives have numerous advantages, they have the following drawbacks. The endless loop belts cannot be repaired when broken, and has to be replaced. Also, changes in the load or tension may cause slippage. They cannot operate in extreme situations since the material is sensitive to the temperature and the moisture reduces the contact surface friction causing slippage. Also, the length of the belt drives cannot be adjusted.
What is the difference between Chain Drive and Belt Drive?
• Belt drives are made of polymers, and chains are made of alloys.
• Chain drives can operate in high temperature and moist conditions, but belt drives cannot.
• Belt drives are not lubricated, whereas the chain drives are lubricated.
• Belt drives undergo slippage, whereas chain drives have no slippage.
• Chain drives use sprocket, while belt drives use sheaves (pulleys).
• Chain drive can operate under high loads, while belt drives can operate under high speed conditions.
• Belt drives are silent, while chain drives are noisy.