Attachment system for an optical unit of a laser rate gyro

The gyroscope has a cylindrical hub formed by a continuous assembly of plane walls (34) distributed about an axis (Delta) such that adjacent walls of hub together form a dihedron with a radial plate of single block activation wheel (30) connected to a cylindrical unit along an edge (36) of the dihedron. Each wall has a bulging portion (37) serving for plane-to-plane fixing of a face of tulip (20) and a thinned portion (34a) that allows a radial displacement degree of freedom of fixing part relative to outer rim (31) in presence of differential thermal expansion between the tulip and the wheel.