2. Chain Dynamics
NOTE: Endless configuration: Manufacturers create connecting com- ponents that are as strong as the chain’s other parts by riveting or other factory processes. The chain is assembled and delivered as an endless configuration. The transmission-ability graph, which is sometimes called a “tent curve” because of its shape, includes the result of the three points covered above. This graph is an important tool when making chain decisions. Figure 2.19 illustrates the concept of a tent curve.
Roller-Bushing Impact
Link Plate Failure
Galling
O
Small Sprocket (rpm)
Figure 2.19 ATransmission-Ability Graph (Tent Curve)
In Figure 2.19, Line O-A is decided according to the chain’s allowable ten- sion, which includes the fatigue strength of the connecting or offset links, as well as the centrifugal force in high-speed rotation. Line B-C is decided by breakage limit of the bushing and roller. In this kind of breakage of the bush- ing and roller, there is no fatigue limit as there is with the link plates. Therefore, it is shown within 15,000 hours of strength-in-limited-duration. Line D-E is decided by the bearing function of the pin and the bushing. The range defined within these three lines (O-A, B-C, and D-E) is the usable range. When the chain is used at low speeds, it is limited by line O-A, the fatigue limit. The conditions of the tent curve shown are: a. Two-shaft wrapping transmission with 100 links of chain. b. Duration of 15,000 hours work. c. Under the Additional Operating Conditions (1 through 5 shown below). Additional Operating Conditions 1. The chain operates in an indoor environment of -10˚C to 60˚C, and there is no abrasive dust. 2. There are no effects from corrosive gas or high humidity. 3. The two driving shafts are parallel with each other and adjusted properly. 4. Lubrication is applied as recommended in the catalog. 5. The transmission is subject to only small fluctuations in load.
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