Roller Chain Design Considerations

Roller chains are used in a wide variety of applications, but most roller chain is used in drives. The shaft speeds of the drives range from less than 50 rpm to nearly 10,000 rpm, and the amoimt of power transmitted ranges from a fraction of a horsepower to more than 1000 hp. The main design considerations for a roller chain to be used on a drive are the various tensile loads, certain types of wear, roller and bushing impact, and galling. 

The major dimensions of standard roller chains are approximately proportional to the chain pitch. These proportions were derived from detailed engineering studies and much experience. These proportions give an excellent balance of properties needed for a roller chain to perform well in a wide variety of applications. The approximate proportions of standard roller chains, conforming to ASME B29.1, are listed below. 

Maximum roller hnk plate height 0.95 X pitch. Maximum pin hnk plate height 0.82 X pitch. 

A roller chain drive or conveyor may be subjected to all of the tensile loads that were listed eariiCT, thus the roller chain must have several tensile strength properties to withstand the wide range of tensile loads that may be imposed on it. The main strength properties that a roller chain must have 

FIGURE 3-8 A diagram of how a standard roller chain elongates as a tensile load is applied. 

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This section reviews the general considerations for the design of roller, silent, engineering steel, and flat-top chains. The considerations differ as the functions of each type of chain differ. The specific design considerations for each class of chain will be covaed later. 

Yield strength is an important consideration in designing roller chains. For standard roller chains, conforming to ASME B29.1, the yield strength is about 60% of the MUTS. Figure 3-8 is a diagram of how a standard roller chain elongates as a tensile load is appUed. 

Wear is a most important consideration in designing roller chains. Roller chains used in drives are normally most affected by joint wear and roller and sprocket wear. Roller chains used in conveyors are most affected by joint wear and either roller and bushing wear or link plate and track wear. More information that is specific to the wear of roller chains follows. 

Chain joint galling is a major consideration in designing drive roller chains only if the chains are intended to be used on high-speed, high-performance drives. 

Roller impact is an important consideration in designing drive roller chains. 

Lubrication and environmental considerations are not discussed here. They are either specified or excluded in the ratings. However, ACA roller chain manufacturers do make chains that are designed to operate with minimal or no lubrication. They also make chains that are designed to operate in adverse environments. 

The straight sidebar conveyor chains discussed here arc steel bushed roUerless chains and steel roller conveyor chains. The main design considerations for these chains are most tensile loads, several types of wear, lubrication, and environment. 

The main design considerations for an engineering steel chain to be used on a drive are very similar to those for a roller chain. These include the various tensile loads, certain types of wear, roller and bushing impact, and galling. 

Link plate and sprocket wear is a consideration in designing silent chains. The link plates engage the sprockets instead of rollers, bushings, or full links. Excessive wear of the mating surfaces of silent chain link plates and sprocket teeth can cause erratic action and increase noise and vibration. 

Wear is probably the most important consideration in designing an engineering steel chain. Joint wear, roller and bushing wear, and sidebar and track wear are the greatest concerns for conveyor chains. Joint wear and roller and sprocket wear are the major concerns for drive chains. 

As was discussed earlier, roller and bushing wear is a very important consideration in designing engineering steel roller conveyor chains. 

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