collar

anglais vers français Technique / Génie Industrie automobile / voitures et camions

Hello,

The document is about Hypocycloidal Engine which involves a gear wheel mechanism.
I can't really identify the part called "collar" in the following text.

Original text: To maximize the benefits of the hypocycloidal design, it would be possible to mount the external (outer) gear in a collar that enabled its orientation to be adjusted slightly. This would allow for variations in the in-cylinder compression and expansion ratios, and could be used in conjunction with external turbo-charging to optimize the cycle over a wide range of power outputs.

Note the outer wheel in this case has inner teeth.
Thanks for your help.