curtained carriage used by women
輧 refers specifically to a curtained carriage used by women, a type of vehicle with a covered enclosure for privacy.
輧 combines 車 (vehicle) with 幷, which likely contributes the sound and may relate to covering or joining, fitting the curtained carriage meaning. The exact historical development is uncertain.
The left side 車 is a vehicle, and the right side 幷 looks like a covered enclosure. Imagine a carriage with curtains drawn, used by women for privacy.
For ビョウ, picture a beautiful curtained carriage: 'beautiful' sounds like ビョウ, and the carriage is the vehicle 車.