Velotegra Hub

With wheel removedNew frame front left

Velotegra is focused on the design, development, and licensing of an innovative new bicycle transmission hub.

The Velotegra hub has the following objectives:

Low internal friction: A hub with improved mechanical efficiency, smoother operation, and lower wear.

High torque capacity: A stronger and more reliable hub, allowing higher loads. A higher load capacity is important for tandem bicycles, direct-drive bicycles, and for installations where the hub is driven by an electrically-assisted drive train.

Higher gear ratios: A hub with ratios that are high enough for a 1:1 chain ratio, allowing a smaller chainwheel, less chain length and weight, and making a chain case less obtrusive. These higher ratios also give the correct ratios for direct-drive.

These objectives are achieved by a bevel-planetary architecture, where the planet, sun, and ring gears are all bevel gears.

This bevel planetary configuration allows the planet gears to be much larger because their size is not vertically constrained between the sun gear and the ring gear. Instead, the planet gears can extend across the width of the hub, making these larger diameters attainable. A larger planet gear diameter is beneficial in hub gears because it allows the teeth of each gear to be much larger, increasing tooth strength; and the increase in tooth pitch gives space for roller teeth, reducing friction and internal wear.

In addition, a bevel-planetary layout results in higher gear ratios, with less complexity than would be possible in a conventional planetary configuration. Higher gear ratios simplify the chain arrangement in a bike because a 1:1 chain ratio is attainable, resulting in less chain length, bulk, and weight; and these higher ratios are compatible with direct-drive, opening up new bicycle design options.

The bevel configuration also increases the minimum gear contact ratio (average number of teeth in engagement), improving the smoothness of the meshing.

A patent for hub has been granted in the United States (US9139254), in the United Kingdom (GB2513959), and in Canada (CA2812588).

A first prototype of the hub has been constructed, shown with the hub shell removed in the picture (above, left) and in the video (below). The hub is shown installed in a direct-drive recumbent bike (above right). With minor changes, the hub may also be installed in a conventional chain-driven bike.

 

Preliminary design work on a second prototype is underway, incorporating several important improvements. A patent application has been filed for this new version.

Since direct-drive is one of the applications of the Velotegra hub, a web page describing the advantages and specific design requirements of the direct-drive recumbent bicycle is included. This page also includes a section outlining the history of development of this type of bike.

If you have any comments or would like further information, please do not hesitate to send a message in the Contact page.

Jeremy Garnet, P. Eng. (Velotegra Inc.)