Patent ID: 7416343

Claim:
A pulley support double row ball bearing comprising: an outer ring having an outer diameter of 65 mm or less and a double row raceway formed on an inner circumferential surface thereof; an inner ring having a double rowraceway formed on an outer circumferential surface thereof; a plurality of balls each 4 mm or less in diameter, and each retained by a retainer between the outer and inner raceways such that they roll freely; and seal rings that seal openings on both ends of an internal space between the inner circumferential surface of the outer ring and the outer circumferential surface of the inner ring where the plurality of balls are disposed; wherein an axial width of the bearing does not exceed 45% of an inner diameter of the inner ring, and by fitting the inner ring around a support member and fitting the outer ring inside a pulley, the pulley is supported such that it rotates freely around the support member; and wherein a portion of each seal ring near an inner circumference thereof and a corresponding axial end surface of the inner ring overlap when viewed from the axial direction, so that a width in a radial direction of an overlap section is between 25% and 80% of a diameter of one of the plurality of balls; and wherein each seal ring includes a plurality of protrusions formed circumferentially on an inside surface at a portion near an inner circumference of the seal ring such that a tip edge of at least one of the plurality of protrusions comes in sliding contact with the corresponding axial end surface of the inner ring.