External rotor gyroscope

In a gyroscope comprising jacket-shaped rotor means with an opening therethrough, a stator located inside the opening of the rotor means, an axle firmly attached to the stator and defining an axis of rotation with the stator having two sides in planes generally normal to said axis, and prestressed ball bearing assemblies at both sides of the stator and mounted on said axle, each bearing assembly including an inner ring and an outer ring with balls therebetween, said rotor means having two ends with end faces thereat in planes generally normal to said axis, said rotor means including an annular jacket member and an annular motor drive member centrally within and secured to the jacket member, said rotor means having, about said opening, an inner surface which at said ends forms bearing surfaces cylindrical about said axis, said outer rings of said bearing assemblies including outer faces with cylindrical circumferential surfaces received directly in said bearing surfaces respectively and flanges abutting said end faces respectively, the improvement comprising:

• said rotor means between said end faces including three parts, namely, a central part and two end parts, said three parts being all within and engaging said jacket member and all defining a straight cylindrical through bore concentric with said axis and being said opening, said motor drive member forming said central part, said rotor means including annular end members forming said end parts respectively, said annular end members having inner walls defining said bearing surfaces and end faces in said planes of said rotor means, said end faces of said end members having annular grooves extending inwardly from said planes of said rotor means, concentric to the axis of rotation and positioned at a distance from said opening such that said inner walls adjacent the end faces of the end members define resilient rim portions against which said outer rings are mounted as aforesaid.