A roller bearing seal includes an insert part and a polymer part connected to the insert part, and the insert part includes an annular-disc-shaped middle section having a radially inner deflection and a radially outer deflection, and a first ratio (L2/L1) of an axial length (L2) of the outer deflection to an axial length (L1) of the inner deflection is less than 0.65.

To obtain a second assembly, first, an outer ring and first roller cassette of a first assembly are supported by a first support tool and a hub wheel of the first assembly is supported by a second support tool, and then the second support tool is moved upward, so that a roller support surface of the second support tool is introduced to the inside of the first roller cassette in the radial direction. Then, after a first seal member is attached to the outer ring, the second support tool is moved downward in accordance with the re-insertion of a cylindrical portion of the hub wheel into the inner periphery of the outer ring, so that a first inner raceway surface is inside of the first roller cassette in the radial direction while the roller support surface is ejected to the lower side of the first roller cassette.

A rolling bearing has a pair of inner rings and an annular groove provided on an outer circumference of a portion where end portions of the pair of inner rings abut against each other. A seal member for a rolling bearing has an elastic portion. The seal member for a rolling bearing is mounted in the annular groove. The elastic portion has an annular proximal end portion that is fixed to one axial end side of the annular groove and an annular extending portion extending from the proximal end portion towards the other axial end side and having on an inner circumference thereof a sliding contact lip configured to be brought into sliding contact with the other axial end side of the annular groove.

To obtain a second assembly, first, an outer ring and first roller cassette of a first assembly are supported by a first support tool and a hub wheel of the first assembly is supported by a second support tool, and then the second support tool is moved upward, so that a roller support surface of the second support tool is introduced to the inside of the first roller cassette in the radial direction. Then, after a first seal member is attached to the outer ring, the second support tool is moved downward in accordance with the re-insertion of a cylindrical portion of the hub wheel into the inner periphery of the outer ring, so that a first inner raceway surface is inside of the first roller cassette in the radial direction while the roller support surface is ejected to the lower side of the first roller cassette.

A rolling bearing has a pair of inner rings and an annular groove provided on an outer circumference of a portion where end portions of the pair of inner rings abut against each other. A seal member for a rolling bearing has an elastic portion. The seal member for a rolling bearing is mounted in the annular groove. The elastic portion has an annular proximal end portion that is fixed to one axial end side of the annular groove and an annular extending portion extending from the proximal end portion towards the other axial end side and having on an inner circumference thereof a sliding contact lip configured to be brought into sliding contact with the other axial end side of the annular groove.