Double row angular ball bearing for CT scanning device

An ultra-thin double-row angular contact ball bearing for a CT scanning device, the ultra-thin double-row angular contact ball bearing comprising:

• an outer member having raceway surfaces in two rows on an inner periphery;
• an inner member having raceway surfaces in two rows on an outer periphery and being arranged on an inner side of the outer member;
• balls in two rows incorporated between the raceway surfaces of the outer member and the raceway surfaces of the inner member;
• and
• retainers configured to hold the balls,
• the inner member being made up of a pair of raceway rings,
• the pair of raceway rings having at least two pairs of positioning holes into each pair of which a positioning member is inserted, wherein a clearance is defined between each of the pairs of positioning holes and the associated positioning member, the clearance being restricted to suppress radial decentering of the pair of raceway rings,
• the pair of raceway rings being fastened together by a plurality of fixing bolts, wherein the centers of the positioning members are located at a different radial position than the centers of the fixing bolts,
• the inner member having an inner diameter of 650 mm or more, and a value of a ratio Db/PCDBALL being 0.03 or less, where Db represents a diameter of each of the balls and PCDBALL represents a pitch circle diameter of the balls,
• the pair of raceway rings having opposed end surfaces that are formed as flat surfaces and being fastened by the plurality of fixing bolts to bring the opposed end surfaces into abutment against each other to apply a preload at a fixed position between the balls and the raceway surfaces,
• the following relationship being set:
• Db/h≤0.26,
• where h represents a radial dimension from a center of each of the balls to the inner diameter of the inner member, and
• the following relationship being set:
• B>A,
• where A represents a radial dimension from the center of each of the plurality of fixing bolts to an outer diameter of the inner member, and B represents a radial dimension from the center of each of the plurality of fixing bolts to the inner diameter of the inner member.