Roller chain is a type of chain transmission used for conveying mechanical power chains. It is widely used in household, industrial, and agricultural machinery, including conveyors, drawing machines, printing machines, automobiles, motorcycles, and bicycles. It is connected by a series of short cylindrical rollers and driven by a gear called a sprocket, making it a simple, reliable, and efficient power transmission device.

　　Roller chains can be made into single row chains and multi row chains. When it is necessary to bear a large load and transmit a large power, multiple rows of chains can be used, as shown in the figure. A multi row chain is equivalent to several ordinary single row chains connected to each other with long pin shafts. Its load-bearing capacity is proportional to the number of rows, but the more rows there are, the more difficult it is to make each row evenly stressed. Therefore, the number of rows should not be too many. Commonly used are double row chains and three row chains.

　　Advantages of roller chain transmission: Compared with belt transmission, it has no elastic sliding, can maintain accurate average transmission ratio, and has higher transmission efficiency; The chain does not require large tension, so the load on the shaft and bearings is relatively small; Will not slip, reliable transmission, strong overload capacity, able to work well under low-speed and heavy loads. Disadvantages: The instantaneous chain speed and instantaneous transmission ratio both vary, resulting in poor transmission stability, impact and noise during operation, making it unsuitable for high-speed situations and situations where the direction of rotation frequently changes.

　　The length of a roller chain is represented by the number of links. It is best to choose an even number of chain links so that when the chains are connected in a circular shape, the outer and inner chain plates are precisely connected, and the joints can be locked with spring clips or split pins. If the number of roller chain links is odd, transitional links need to be used. When the chain is under tension, the transition links also have to bear additional bending loads, which should usually be avoided.

　　Roller chains effectively transmit power without slipping. The speed ratio is fixed and absolute. The efficiency of the roller chain is 98%, and under good lubrication, its efficiency is quite good for any load. This efficiency can be maintained throughout its lifespan. Roller chains have versatility and can still operate effectively in harsh environments such as dirt, oil, and mixed air. A single power source can simultaneously drive multiple shaft outputs, and the speed can be adjusted by the size of the ratchet wheel.

　　The roller chain has the ability to absorb vibration, and the chain itself has elasticity. When the oil film is stored in various components, it can protect the shaft and motor from impact force and strain. Light weight, small space occupation, narrow width, can be installed in extremely small spaces, and takes up less space per unit of transmitted horsepower. The roller chain is durable, as the load is shared by many teeth on the spur gear, resulting in less force on each individual gear and ensuring its lifespan.