Gears sizing

So that reliable test results could be obtained, five test repetitions of four different worm gears described in the previous chapter were carried out, starting always from the same point and with identical rotation direction. On this way, there will be four rolling tests for each gear size tested, assuring if there is any influence on the result derived from the variation of the transmission ratio. 

Appliances also make broad use of plastic power gears. Some larger applications, like washing machine transmissions, have pushed the limit on gear size, often as a replacement for metal. Plastic gears are present in many other areas, for example, damper drives in HVAC zone controls, valve actuators in fluid devices, automatic flushers in public restrooms, power screws that shape control surfaces on small aircraft, and gyro and steering controls in military applications. 

Bearing and gear sizing, to be in accordance with IS076 for ball bearings and ISO 6886 for gears. 

Available sizes range from shelf areas of 0.4 to 67 m" (4 to 726 ft"). These are available in several manufacturers standards, either as system components or with arrxihary gear as packaged systems. 

Fatty-acid soaps Alkali, alkaline earth, and other metal soaps sodium stearate aluminum stearate Gear oils paper stock paper sizing glue solutions... 

Serviee faetors and material index number tabulation are provided for various typieal applieations, allowing the determination of the K faetor. Gear tooth size and geometry are seleeted so that bending stresses do not exeeed eertain limits. The bending stress number is given by... 

The API, with help from gear manufacturers, has a 1977 standard (API 613) for rating gears. (See Chapter 4.) A common procedure for comparing and sizing gear is based on the tooth pitting index, the K factor... 

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