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.

A dental handpiece (1) having a drive (3) of a tool (4), which drive is located in a head housing (2), has at least one media-conducting line arranged in the head housing, which media-conducting line has an outlet opening to the tool, and a tool receptacle (16) arranged in a drive chamber, which tool receptacle is rotatably supported by means of a rolling bearing (11) in a support (14) of the head housing (2) on a side of the drive chamber facing the tool. The rolling bearing has an outer race (13), which is supported against the head housing (2) radially in the support (14) in the area of a raceway (22) and which has a sub-area (21), the outside diameter D2 of which is reduced compared to the outside diameter D1 in the area of the raceway (22). The head housing has a housing projection (23), which extends into the area of the reduced outside diameter D2, and the media-conducting line (17) runs at least partially through said housing projection (23).

A dental handpiece and method of turbine support therein, comprises a turbine wheel having a rotor shaft rotatably supported by a housing via ball bearings, and configured to rotationally drive a clamping chuck, at least one of the ball bearings including, an inner ring arranged on the rotor shaft, the inner ring having a raceway, an outer ring, having an outer raceway movably supported by the housing, and balls arranged between and guided by the inner and outer raceways. The raceway of the inner ring, in cross section, has a concave shape with a curvature corresponding to a radius of the balls. Optionally, the raceway of the outer ring, in cross section, has, in a central area, a first curvature with a first radius and, adjoining the central area, a second curvature with a second radius, the first radius being smaller than the second. Optionally, the raceway of the outer ring has a substantially parabolic profile.

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.

The present invention relates to a dental and/or surgical instrument (1) comprising a motor that drives a tool by way of a tool holder (24, 25, 27) situated in the head of the dental and/or surgical instrument (1), the tool holder (24, 25, 27) being supported in the head of the dental and/or surgical instrument (1) by at least a first ball bearing (21) and a second ball bearing (22), in which the first ball bearing (21) and the second ball bearing (22) are positioned in a cartridge (10) which is inserted into the head of the dental and/or surgical instrument (1), and in which the cartridge (10) comprises a single bore (80) for the mounting and guiding of both the first ball bearing (21) and the second ball bearing (22). The present invention additionally relates to a cartridge (10) to be inserted into the head of such a dental and/or surgical instrument.

The present invention relates to a cage for a rolling bearing, in particular for a ball bearing, to a rolling bearing with a cage and to the use of a cage in a high-speed rolling bearing with a characteristic speed value ndm>1,000,000 mm/min, in particular for industrial spindle-bearing applications and in the medical sector, in particular in dental technology.

A disposable dental instrument of the compressed air drive type is disclosed for use in performing dental procedures on a workpiece. The disposable dental instrument is constructed from two mating shells and a core. Each shell incorporates a mating surface and the shells are joined using various bonding methods to ensure a waterproof, high quality dental instrument. An elongated body has conduits penetrating a base at one end of the body. The conduits allow entry of a light beam, a pressurized water stream, and a compressed air stream into the body. The base includes attachment threads for securing the body to a source of the light beam, pressurized water stream, and compressed air stream. Pluralities of passageways are in communication with the conduits for conducting the light beam, the water stream, and the air stream through the body. A head at the opposite end of the body rotatably mounts a turbine shaft on bearing surfaces which inhibit vibration and noise. The turbine shaft includes a turbine impeller and a clamping hole for removable attachment of a dental bur to the shaft. The air stream drives the impeller at a high speed for rotating the bur about a rotational axis. An opening in the body adjacent to the head allows release of the light beam, the pressurized water stream, and a portion of the compressed air stream in a direction toward the distal end of the bur so that the bur, the light beam, the water stream, and the air stream may all converge on the workpiece.