A rolling bearing includes an outer ring, an inner ring, a plurality of rolling bodies, and a seal member. An outer peripheral portion of the seal member is fixed by a retaining ring to a groove portion formed on an inner peripheral surface of the outer ring and an inner peripheral portion of the seal member is elastically deformable. The seal member includes an inclined portion. 1≤Ts/Sct≤10 is satisfied when Ts is a circumferential gap of the retaining ring at a time when the seal member and the retaining ring are attached to the groove portion of the outer ring and Sct is an axial thickness of a part of the seal member in contact with the retaining ring.

A rolling bearing includes an outer ring, an inner ring, a plurality of rolling bodies, and a seal member. An outer peripheral portion of the seal member is fixed by a retaining ring to a groove portion formed on an inner peripheral surface of the outer ring and an inner peripheral portion of the seal member is elastically deformable. The seal member includes an inclined portion. The seal member satisfies 0.25≤Skn/Skt≤2.5 when Skn is a radial length from an inclination start part of the inclined portion on an inside in an axial direction to an outermost diameter position of a part of contact of the seal member with an outer peripheral surface of the inner ring and Skt is a thickness of the inclined portion in a direction perpendicular to an inclination direction.

When the compressed air is not applied, an inclined surface, which is positioned at an upstream side with respect to the supply direction of the compressed air, of the lip part is in contact with the inclined surface of the inner ring. When the compressed air is applied, a contact area between the inclined surface, which is positioned at the upstream side with respect to the supply direction of the compressed air, of the lip part and the inclined surface of the inner ring becomes smaller, as compared to when the compressed air is not applied.

When the compressed air is not applied, an inclined surface, which is positioned at an upstream side with respect to the supply direction of the compressed air, of the lip part is in contact with the inclined surface of the inner ring. When the compressed air is applied, a contact area between the inclined surface, which is positioned at the upstream side with respect to the supply direction of the compressed air, of the lip part and the inclined surface of the inner ring becomes smaller, as compared to when the compressed air is not applied.

The dental handpiece consists of a housing with a handle and a turbine that can be operated with compressed gas or compressed air. The rotational movement of the turbine driven by compressed gas is transmitted to the dental tool via a rotor shaft and a chuck. The rotor shaft is rotatably supported by at least one axial groove ball bearing. The radial rigidity required for operating a dental handpiece is achieved by axially preloading the ball bearings. Projections on the housing and the shaft disc of the at least one axial groove ball bearing allow the axial groove ball bearing to be used as radial groove ball bearings. The proposed design of the dental handpiece exhibits little power loss or frictional loss in comparison to dental handpieces with radial groove ball bearings, and slip and drilling friction components can be virtually completely prevented in particular.

The disclosure relates to a head bearing assembly for a dental or surgical handpiece, comprising an outer sleeve, in which at least four radial bearings are arranged, which enclose an axis of rotation and each have their own bearing outer ring or a common bearing outer rings, wherein the bearing outer rings are surrounded radially on the outside by the outer sleeve in the circumferential direction about the axis of rotation, and each radial bearing has at least one or exactly one rolling element row with rolling elements which are arranged one behind the other in the circumferential direction and rolling in the respective bearing outer ring.

The head bearing assembly according to the disclosure is characterized in that the at least four radial bearings have a common, integral bearing inner ring on which the rolling elements are arranged in rolling contact.

A rolling bearing includes: an outer ring including an outer ring raceway surface on an inner peripheral surface; an inner ring including an inner ring raceway surface on an outer peripheral surface; a plurality of rolling elements rotatably arranged between the outer ring raceway surface and the inner ring raceway surface; and a sealing member fixed to a seal mounting groove formed on an axial end portion of the outer ring by a retaining ring, the sealing member sealing an axial end portion of a bearing internal space between the outer ring and the inner ring. The sealing member includes a protruding portion at a radial outer end portion, and an outer diameter of the sealing member is larger than an outer diameter of the retaining ring in the seal mounting groove.

A two-part ball bearing cage includes two, in particular at least substantially identical, cage parts forming an even-numbered plurality of ball pockets for receiving a corresponding number of balls having a predeterminable ball diameter. Each cage part has an annular body on which substantially evenly distributed webs are disposed in the circumferential direction to form the ball pockets. A distance in the circumferential direction between two webs that are adjacent in the circumferential direction approximately corresponds to the sum of twice the ball diameter and a width of the web in the circumferential direction. A ball bearing having the ball bearing cage and a method for assembly of the ball bearing are also provided.

When compressed air does not act, a seal member is in contact with an outer periphery of an inner ring. When the compressed air acts, a contact area between the seal member and the outer periphery of the inner ring is reduced, as compared to when the compressed air does not act. Accordingly, it is possible to provide an air turbine bearing unit capable of promptly stopping rotation.

In order to make a bearing, such as a roller bearing, insensitive to a lack of maintenance lubrication or irregular maintenance lubrication while at the same time retaining its mechanical performance, at least one bearing part of the bearing is provided at least partially with an oleophilic adhesion promoter layer. The adhesion promoter layer binds a lubricant layer of the bearing to the bearing part provided with the adhesion promoter layer. The adhesion promoter layer is bonded to an elemental-iron-free surface of a bearing part body. The removal of free iron from the bearing part body surface is carried out with nitric acid, chromate solution and/or citric acid. The treated bearing part has an oleophilic anti-corrosion adhesion promoter layer. The bearing may be used in pressure-operated devices, in particular in turbine handpieces used by dentists, because the loss of the lubricant layer during operation of the device was particularly high.