The chain transmission is a meshing transmission, and the average transmission ratio is accurate. It is a mechanical transmission that transmits power and movement by using the meshing of the chain and the teeth of the sprocket.
the chain
Chain length is expressed in number of links. The number of chain links is preferably an even number, so that when the chain is connected into a ring, the outer chain plate and the inner chain plate are just connected, and the joints can be locked with spring clips or cotter pins. If the number of links is odd, transition links are required. When the chain is under tension, the transition link also bears additional bending loads and should generally be avoided. The toothed chain is composed of many punched toothed chain plates connected by hinges. In order to avoid the chain falling when meshing, the chain should have a guide plate (divided into inner guide type and outer guide type). The two sides of the toothed chain plate are straight sides, and the side of the chain plate meshes with the tooth profile of the sprocket during operation.The hinge can be made into a sliding pair or a rolling pair, and the roller type can reduce friction and wear, and the effect is better than that of the bearing pad type. Compared with roller chains, toothed chains run smoothly, have low noise, and have a high ability to withstand impact loads; but their structures are complex, expensive, and heavy, so their applications are not as extensive as roller chains. Toothed chains are mostly used for high-speed (chain speed up to 40m/s) or high-precision motion transmission. The national standard only stipulates the maximum and minimum values of the tooth surface arc radius, the tooth groove arc radius and the tooth groove angle of the tooth groove of the roller chain sprocket (see GB1244-85 for details). The actual face profile of each sprocket should be between the largest and smallest cogging shapes. This treatment allows great flexibility in the design of the sprocket tooth profile curve. However, the tooth shape should ensure that the chain can enter and exit meshing smoothly and freely, and it should be easy to process. There are many kinds of end tooth profile curves that meet the above requirements. The most commonly used tooth shape is “three arcs and one straight line”, that is, the end face tooth shape is composed of three arcs and a straight line .
sprocket
The two sides of the tooth shape of the sprocket shaft surface are arc-shaped to facilitate the entry and exit of the chain links. When the tooth shape is processed with standard tools, it is not necessary to draw the end face tooth shape on the sprocket working drawing, but the sprocket shaft surface tooth shape must be drawn to facilitate the turning of the sprocket. Please refer to the relevant design manual for the specific dimensions of the shaft surface tooth profile. The sprocket teeth should have sufficient contact strength and wear resistance, so the tooth surfaces are mostly heat-treated. The small sprocket has more meshing times than the large sprocket, and the impact force is also greater, so the material used should generally be better than that of the large sprocket. Commonly used sprocket materials are carbon steel (such as Q235, Q275, 45, ZG310-570, etc.), gray cast iron (such as HT200), etc. Important sprockets can be made of alloy steel. The sprocket with small diameter can be made into solid type; the sprocket with medium diameter can be made into orifice type; the sprocket with larger diameter can be designed as combined type. If the teeth fail due to wear, the ring gear can be replaced. The size of the sprocket hub can refer to the pulley.
Post time: Aug-23-2023