What is a drive chain

According to the structure, it can be divided into roller chains, toothed chains and other types, among which roller chains are the most widely used. The structure of the roller chain is shown in Figure 1, which is composed of an inner chain plate 1, an outer chain plate 2, a pin 3, a sleeve 4 and a roller 5. Among them, the inner chain plate and the sleeve, the outer chain plate and the pin shaft are respectively connected by interference fit, which are called inner and outer chain links; the gap between the roller and the sleeve, the sleeve and the pin shaft is a clearance fit. When the inner and outer chain plates are relatively deflected, the sleeve can rotate freely around the pin shaft. The roller is looped on the sleeve. When working, the roller rolls along the tooth profile of the sprocket. Reduces gear tooth wear. The main wear of the chain occurs on the contact surface of the pin shaft and the sleeve. Therefore, a small gap should be left between the inner and outer chain plates to allow the lubricating oil to penetrate between the friction surfaces. The chain plate is generally made into an "8" shape, so that each cross section has nearly equal tensile strength, and also reduces the mass of the chain and the inertial force during movement.

The parts of the chain are made of carbon steel or alloy steel and heat treated to improve strength, wear resistance and impact resistance. Roller chains can be made into single-row chains and multi-row chains, and when transmitting high power, double-row chains or multi-row chains can be used. The carrying capacity of the multi-row chain is proportional to the number of rows. However, due to the influence of precision, the load on the side-by-side chain is not easy to be uniform, so the number of rows should not be too many.

The roller chain has been standardized. my country's chain standard GB 1.243.1-83 divides it into two series, A and B. The A series is commonly used. The main parameters are shown in the following table. The chain number in the table is consistent with the corresponding international chain number. The pitch value is the chain number multiplied by 25.4/16mm. The basic parameters of the roller chain are the pitch p, the outer diameter of the roller d1, etc., where the pitch p is the main parameter of the roller chain. The larger the pitch, the larger the size of each part of the chain, and the greater the power that can be transmitted.

The length of the chain is represented by the number of links Lp, and the number of links is preferably an even number, so as to facilitate the connection of the inner and outer chain plates when the chain is connected, and a split pin or a spring lock plate can be used at the joint. If the number of chain links is odd, the transition link should be used at the joint. When the chain is loaded, the transition link not only bears the tensile force, but also bears additional bending load, which should be avoided as much as possible.