A ring rolling device for enlarging a ring blank includes a press element, a rotatably mounted mandrel and an advancing arrangement in which the mandrel is rotatably mounted with a first end part in a first rolling bearing and with a second end part in a second rolling bearing. The ring blank can be mounted around the mandrel. By means of the advancing arrangement, the mandrel is movable towards the press element and away from the latter again, wherein a roll gap which decreases in size, and in which the ring blank is rolled, is formed between the mandrel and the press element. The two rolling bearings are arranged axially fixed in the advancing arrangement, and the mandrel is mounted so as to be axially movable relative to these two rolling bearings.

A ring rolling device for enlarging a ring blank includes a press element, a rotatably mounted mandrel and an advancing arrangement in which the mandrel is rotatably mounted with a first end part in a first rolling bearing and with a second end part in a second rolling bearing. The ring blank can be mounted around the mandrel. By means of the advancing arrangement, the mandrel is movable towards the press element and away from the latter again, wherein a roll gap which decreases in size, and in which the ring blank is rolled, is formed between the mandrel and the press element. The two rolling bearings are arranged axially fixed in the advancing arrangement, and the mandrel is mounted so as to be axially movable relative to these two rolling bearings.

This invention relates to a combined ring rolling method for spherical valve body, which has the following procedures: 1) design for ring blank by computing ring blank volume and selecting reasonable rolling ratio according to the dimensions of forged ring; 2) design for rolling gap which includes the shapes and dimensions of working surfaces of main roll, mandrel and passive rolls according to the dimensions of ring blank and forged ring, the stable deformation condition of combined ring rolling and structure requirement of rolling equipment; 3) rolling forming with three stages of surface cross rolling, ring rolling and shaping by controlling of feeding speed of main roll and working positions of passive rolls. This invention has the technical economical advantages of low consumptions of energy and materials, high productivity and low production cost.

A wheel bearing device includes a hub wheel and a wheel bearing press-fitted onto the hub wheel. A clearance is formed between at least one inner race and the hub wheel such that the at least one inner race is out of contact with the hub wheel at a position where an action line intersects with the hub wheel, the action line being a contact angle of the balls on the outboard side with the at least one inner race. A large-diameter side radially inner surface of the at least one inner race is formed as a curved surface opposed to the inner rolling surface of the at least one inner race. An axial dimension La of a corner portion of the hub wheel is 1.5 times or more as large as a radial dimension Lr thereof.

A wheel bearing device includes a hub wheel and a wheel bearing press-fitted onto the hub wheel. A clearance is formed between at least one inner race and the hub wheel such that the at least one inner race is out of contact with the hub wheel at a position where an action line intersects with the hub wheel, the action line being a contact angle of the balls on the outboard side with the at least one inner race. A large-diameter side radially inner surface of the at least one inner race is formed as a curved surface opposed to the inner rolling surface of the at least one inner race. An axial dimension La of a corner portion of the hub wheel is 1.5 times or more as large as a radial dimension Lr thereof.

A method for producing a composite rolling bearing (1) having a bearing flange (3) and at least one rolling bearing (4, 5) held on the bearing flange (3) by an inner ring (6, 7). In order to be able to fix the inner ring (7) on the bearing flange (3) with axial preloading without expansion, the inner ring (7) is acted upon by a holding-down device (23) that radially holds down the inner ring (7) and is preloaded against the inner ring (7) by a regulated axial force (F), and, by way of an advancing cone (21) introduced radially on the inside axially into the bearing flange (3), material (11) present on the bearing flange (3) is displaced radially towards the outside into a recessed formation (15, 16) in the inner ring (7).

A method for producing a composite rolling bearing (1) having a bearing flange (3) and at least one rolling bearing (4, 5) held on the bearing flange (3) by an inner ring (6, 7). In order to be able to fix the inner ring (7) on the bearing flange (3) with axial preloading without expansion, the inner ring (7) is acted upon by a holding-down device (23) that radially holds down the inner ring (7) and is preloaded against the inner ring (7) by a regulated axial force (F), and, by way of an advancing cone (21) introduced radially on the inside axially into the bearing flange (3), material (11) present on the bearing flange (3) is displaced radially towards the outside into a recessed formation (15, 16) in the inner ring (7).

There is provided a method for manufacturing ring-shaped members at a good yield and high production efficiency. To achieve this object, the following is performed. A single (a sequence of) forging produces a joined body formed by radially coupling four cylindrical portions with different inner diameter sizes. A cylindrical member that has the largest inner diameter size and a cylindrical member that has the third largest inner diameter size after the forging are employed as ring-shaped members without change. A rolling process is performed on respective cylindrical member that has the smallest inner diameter size and cylindrical member that has the second largest inner diameter size to obtain ring-shaped members. Thus, two sets of ring-shaped members are obtained as two sets of inner rings and outer rings.

There is provided a method for manufacturing ring-shaped members at a good yield and high production efficiency. To achieve this object, the following is performed. A single (a sequence of) forging produces a joined body formed by radially coupling four cylindrical portions with different inner diameter sizes. A cylindrical member that has the largest inner diameter size and a cylindrical member that has the third largest inner diameter size after the forging are employed as ring-shaped members without change. A rolling process is performed on respective cylindrical member that has the smallest inner diameter size and cylindrical member that has the second largest inner diameter size to obtain ring-shaped members. Thus, two sets of ring-shaped members are obtained as two sets of inner rings and outer rings.

A ring rolling device includes a drive roller and a rotatable revolving drum, in which five mandrels are rotatably mounted. Ring blanks can be mounted around the mandrels. By rotating the revolver drum, the mandrels move towards and away from the drive roller. The revolver drum is arranged in relation to the drive roller in such a way, that by rotating the revolver drum a decreasing roll gap is formed between a mandrel approaching the drive roller and the drive roller, in which roll gap a ring blank mounted around the mandrel is rolled during the rotating of the revolver drum. The revolver drum has four rotatably mounted support rollers, said support rollers supporting the mandrel in the direction of the rotational axis of the revolving drum, such that, during the rolling process, the mandrel is located between the support rollers and the press element.