According to different uses, chains can be divided into three categories: lifting chains, traction chains and transmission chains. The lifting chain is mainly used for lifting heavy objects in hoisting machinery, and its working speed v≤0.25m […]
According to different uses, chains can be divided into three categories: lifting chains, traction chains and transmission chains. The lifting chain is mainly used for lifting heavy objects in hoisting machinery, and its working speed is v≤0.25m / s; the traction chain is mainly used for moving heavy objects in chain conveyors, and its working speed is v≤4m / s; the driving chain is used for Movement and power are transmitted in general machinery, usually working speed v≤15m / s. There are two types of drive chain: toothed chain and roller chain. The toothed chain is driven by the meshing of a specific toothed chain and a sprocket. The toothed chain is stable and has low noise, so it is also called a silent chain transmission. The toothed chain allows a working speed of up to 40m / s, but it has high manufacturing cost and heavy weight, so it is mostly used in high-speed or high-accuracy applications. There are two types of chains used in power transmission: sleeve roller chains and toothed chains. The sleeve roller chain is composed of an inner link plate, an outer link plate, a sleeve, a pin, and a roller. The outer chain plate is fixed on the pin and the inner chain plate is fixed on the sleeve. The roller and the sleeve and the sleeve and the pin can rotate relative to each other. Therefore, the meshing between the chain and the sprocket is mainly rolling friction. The sleeve roller chain can be used in a single row and multiple rows, and multiple rows can be used to transfer larger power. The sleeve roller chain is lighter in weight, longer in life and lower in cost than a toothed chain. It is widely used in power transmission. The toothed chain is assembled by using pins to connect a plurality of pairs of chain pieces with a working angle of 60 °. The working surface of the chain plate meshes with the sprocket. To prevent the chain from falling off the sprocket during work, the chain is equipped with an inner guide or an outer guide. When engaged, the guides fit into the corresponding guide grooves on the sprocket (Figure 1). Toothed chain transmission is smooth and has low noise, so it is also called silent chain, which is often used for high-speed transmission. The tooth profile of the sleeve roller chain and the toothed sprocket should ensure that the energy-saving chain can freely enter or exit the meshing, the impact is small when the meshing, and the contact is good when meshing.
Compared with the belt drive, the chain drive has no elastic sliding and slipping, and can maintain an accurate average transmission ratio. The required tension force is small, and the pressure on the shaft is also small, which can reduce the friction loss of the bearing. The structure is compact; Work under severe environmental conditions such as high temperature and oil pollution. Compared with gear transmission, chain transmission requires lower manufacturing and installation accuracy; when the center distance is large, the transmission structure is simple. The instantaneous chain speed and instantaneous transmission ratio are not constant, so the transmission stability is poor, and there is a certain impact and noise in the work. The average transmission ratio of the chain drive is accurate, the transmission efficiency is high, the distance between the shafts is large, and it can be used in the environment with high temperature and humidity. The ratio fluctuates, and the transmission noise is relatively large. Because the chain link is rigid, there is a polygon effect (ie, non-uniform motion). This kind of motion characteristics changes the instantaneous transmission ratio of the chain transmission and causes additional dynamic loads and vibrations. It must be considered when selecting chain transmission parameters. Chain drive is widely used in transportation, agriculture, light industry, mining, petrochemical and machine tool industries.