A wheel support bearing assembly, which enables an increase in the strength and the fatigue strength of its wheel mounting flange or vehicle body fitting flange against high stress and repeated stress and the suppression of the increase of the number of processes, includes an inner member and an outer member rotatable relative to each other through rolling elements. The flange is formed on the inner member or the outer member, for example, a hub. A component part having the flange is a hot-forged product of steel in which a matrix portion is formed as a standard structure and the non-standard structural portion is formed on the surface of the flange. The non-standard structure is formed of either of a fine ferrite/pearlite structure, an upper bainite structure, a lower bainite structure, and a tempered martensite structure, or mixture of two or more of these structures.

Bearing device for wheel

A bearing device for drive wheel, wherein the end part of a hub wheel (30) is elastically deformed to the outer radial side to form a radial crimped part (37) to integrally form the hub wheel (30) with an inner wheel (40) fitted onto the outer periphery of the hub wheel, the outside joint member (72) of a constant velocity universal joint (70) is press-fitted to the inner periphery of the hub wheel (30) to fit serrations (81) on the inner periphery of the hub wheel (30) to the serration shaft part (82) of the outside joint member (72), and the tooth profile of the serrations (81) on the inner periphery of the hub wheel (30) is controlled within a specified range through the entire axial length thereof to suppress a reduction in diameter of the serrations (81) according to the crimping.

Bearing device for drive wheel

A bearing apparatus for wheel with ensured high durability by including a part with improved fatigue strength in a non-hardened portion includes an outer member, an inner member, and a roller. The inner member includes a hub ring made of steel and having a wheel attachment flange formed. The hub ring has a hardened portion hardened to attain at least 50 HRC as a result of quench hardening and a non-hardened portion which is a portion other than the hardened portion. Compressive stress in a range from at least 50 MPa to at most 500 MPa remains in the surface of the non-hardened portion.

Bearing apparatus for wheel

PROBLEM TO BE SOLVED: To provide a method for manufacturing a flange structure by which the occurrence of crack in material can be restrained and a high quality hub ring can be manufactured as a result SOLUTION: The method for manufacturing the flange structure is provided for forming the flange structure equipped with a shaft member 1 and a flange 2 extended to an outer diameter direction from the shaft member 1 The method comprises: a first step 21 in which a forming blank 36 is formed by charging a solid or a hollow blank material 35 into a cold closed forging die device, in a warm- or a hot-forging range; and a second step 22 in which the flange 12 for fitting a wheel is formed by means of the cold closed forging die device by charging the forming blank 36 into the cold closed forging die device Before charging the blank into the cold closed forging die in the second step 22, a softening treatment 23 and a lubricating treatment 24 are performed COPYRIGHT: (C)2008,JPO&INPIT

Method for manufacturing flange structure

A wheel bearing device of the invention includes a flanged shaft member (1) that includes a shaft portion (10) to which a rolling bearing (41) is assembled, a fitting shaft portion (30) that is formed on one end side of the shaft portion (10) and that is fitted to a center hole of a wheel, and a plurality of flange portions (21) that extend radially outward on an outer peripheral surface located between the shaft portion (10) and the fitting shaft portion (30) and each of which has a through bolt hole (24) in which a hub bolt (27) for fastening the wheel is arranged. Each flange portion (21) of the wheel bearing device is formed by side extrusion when a forged recess (33) is formed at a center of an end surface of the fitting shaft portion (30) by cold forging. An edge portion (21e) of a cross-sectional shape taken perpendicularly to a longitudinal direction of each flange portion (21) is formed in an R-chamfered shape.

Wheel bearing device and manufacturing method therefor

A bearing device is provided with a bearing ring and a shaft body that is made of carbon steel including pearlite having a cementite layer structure, and has an end portion caulked onto the bearing ring, and in this device, at least in the end portion of the shaft body, the layer gap of the cementite in the pearlite is made greater.

Daisaku Koyo Seiko Co. Ltd. Tomita

Papers

Bearing device and method of manufacturing the bearing device