High speed polymer gearboxes deliver material gains
20 July 2016
The ongoing development of advanced, heat resistant materials such as polymers is providing today’s machine designers with practical and effective solutions.
A good example of this is the high speed polymer gearboxes developed by transmission and control specialists ROTALINK which have been successfully used for diverse applications, ranging from welding wire feeders to coffee grinders.
Where the challenge is to reduce weight, options such as high speed polymer gearboxes have an important role to play. Increasing the size of a polymer gear to add strength doesn’t add weight or cost as quickly compared to a metal one. This allows larger gears to be better able to spread load to be used at a given price point, making the higher strength of metal less relevant than it first appears. As well as enabling larger gears, the fast cycle time of the injection moulding process makes it cost-effective to use more gears to achieve a given ratio.
Smaller ratios between each gear results in a stronger gearbox.
Polymer gearboxes are ideal where high power is required for shorter periods of time, such as in machines for grinding of coffee and where applications require larger gearboxes, for example desiccant drives, display turntables, vending machines and peristaltic pumps. In this type of application there is little time for heat to build-up which makes one of the most significant advantages of metal (superior heat resistance) irrelevant. Where the application calls for weight to be minimised, such as wire feeding for portable MIG welders which typically require a low duty cycle, polymer gears are also beneficial.
It is common practice in the miniature power transmission industry to use metal in the final stages of a gear train, where load is heaviest and polymer before that. However, Rotalink takes a different approach. Polymer materials make it practical to add a large planetary gear stage to the end of a conventional spur gear train.
This configuration, using polymers, has been developed by Rotalink and is marketed as a hybrid planetary-spur gearbox.
Rotalink offer the flexibility to work with customers at the early stages of design concepts, customising output shafts and the mounting dimensions of its gearboxes to ensure they fit into existing designs.
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