What is a roller chain?

Roller chain is a kind of chain used to transmit mechanical power. It is a type of chain drive. It is widely used in household, industrial and agricultural machinery, including conveyors, plotters, printing machines, automobiles, motorcycles, and bicycles.It is linked together by a series of short cylindrical rollers and is driven by a gear called a sprocket. It is a simple and reliable power transmission device.

Introduction to Roller Chain

Roller chain usually refers to the precision roller chain for short pitch transmission. It has a wide range of applications and a large output.Roller chains are divided into single row and multiple rows, which are suitable for small power transmission.The basic parameter of the roller chain is the chain pitch p, which is equal to the number of the roller chain multiplied by 25.4/16 (mm).There are two suffixes in the chain number, A and B, indicating two series, and the two series complement each other.

Roller chain composition

As shown in the figure, the roller chain is composed of inner chain plate 1, outer chain plate 2, pin shaft 3, sleeve 4 and roller 5.The inner chain plate and the sleeve, the outer chain plate and the pin are all interference fit; the roller and the sleeve, and the sleeve and the pin are all clearance fits.When working, the inner and outer chain links can be relatively flexed, the sleeve can rotate freely around the pin shaft, and the roller is sleeved on the sleeve to reduce the wear between the chain and the sprocket.In order to reduce the weight and equalize the strength of each section, the inner and outer chain plates are often made into a "8" shape.Each part of the chain is made of carbon steel or alloy steel.Usually after heat treatment to achieve a certain strength and hardness.

Roller chain pitch

The center distance between two adjacent pins on the chain is called the chain pitch, denoted by p, which is the main parameter of the chain.When the pitch increases, the size of each part in the chain increases accordingly, and the transmittable power increases accordingly.The chain pitch p is equal to the roller chain number multiplied by 25.4/16 (mm).For example, chain number 12, roller chain pitch p=12×25.4/16=19.05mm.

The structure of the roller chain

Roller chains can be made into single-row chains and multiple-row chains.When it is necessary to withstand large loads and transmit large power, multi-row chains can be used, as shown in the figure.The multi-row chain is equivalent to several ordinary single-row chains connected with each other with long pins, and its carrying capacity is proportional to the number of rows, but the more rows there are, the more difficult it is to make the force of each row uniform, so the number of rows It should not be too much. Commonly used are double-row chain and three-row chain. 

Roller link head form

The length of the chain is expressed by the number of chain links. Generally, even-numbered chain links are used. In this way, cotter pins or spring clips can be used at the joints of the chain as shown in Figures (a) and (b). The former is used for large-pitch chains, and the latter is used For small pitch chains.When the chain link is fixed by pieces, when the number is odd, the transition link should be adopted, as shown in figure (c).Since the bending chain plate of the transition link will generate additional bending moment when it is tensioned, it should generally be avoided as much as possible.