A ball bearing includes an outer ring having at two outer raceways and an inner ring having two inner raceways. A plurality of balls is disposed in each of the two inner and outer raceways. The plurality of balls include load bearing balls and spacer balls. The spacer balls are disposed between the load bearing balls. Each of the load bearing balls has a single point of contact with each of the two inner and outer raceways. The load bearing balls are preloaded between the outer ring and the inner ring at predetermined force.

A rolling bearing wherein the conventional cage is replaced by independent spacers, one per pair of neighbor rolling elements, each spacer is disposed and trapped between neighbor rolling elements, each spacer is supported on its neighbor rolling elements and is preventing them from coming into contact with each other, each spacer comprising, preferably, a case and a number of auxiliary rolling elements, resulting in rolling bearings having higher load capacity and reduced sliding friction, also a method to improve the conventional cylindrical roller bearings, the conventional ball bearings and the conventional thrust roller bearings.

A rolling bearing wherein the conventional cage is replaced by independent spacers, one per pair of neighbor rolling elements, each spacer is disposed and trapped between neighbor rolling elements, each spacer is supported on its neighbor rolling elements and is preventing them from coming into contact with each other, each spacer comprising, preferably, a case and a number of auxiliary rolling elements, resulting in rolling bearings having higher load capacity and reduced sliding friction, also a method to improve the conventional cylindrical roller bearings, the conventional ball bearings and the conventional thrust roller bearings.

A separator for rolling elements of a bearing includes a body formed of a composite material and having a central pocket sized to receive one of a plurality of rolling elements, a first contact end to contact one adjacent rolling element and an opposing, second contact end to contact another adjacent rolling element. The composite material includes a mixture of a polymer base, reinforcing fibers and a lubricant, preferably, polyetherimide, short strand carbon fibers and molybdenum disulfide. The separator body is sized such that a first distance between a pocket centerline and the first contact end establishes a desired spacing distance between the rolling element within the pocket and the one adjacent one rolling element and a second distance between the centerline and the second contact end establishes a desired spacing distance between the rolling element within the pocket and the other adjacent rolling element.

An axial air movement fan having a plurality of variable pitch fan blades (2), extending radially from a hub (4) rotatable about a main axis (3), each blade (2) further being pivotable about its radial axis to vary the blade pitch. The blades (2) each are mounted on an associated bearing (5) mounted on said hub, the bearing comprising a ball bearing having a first radially inner race (25) fast the blade (2) and a second radially outer race (26) rotationally fast to the hub (4). The balls (14) in the bearing are separated by separators (15), each separator being generally cylindrical and having its cylindrical axis coaxial with the orbital axis (22) of the orbit of the balls (14) and being adapted to rotate about the said orbital axis (22), the side faces of the separator each having a part spherical recess (16) adapted to receive a ball (14). Rotation of the separator (15) about the orbital axis (22) is such as to entrain lubricant in the bearing and to bias the lubricant from adjacent the outer race (26) over the balls (14) towards the inner race (25).

An axial air movement fan having a plurality of variable pitch fan blades (2), extending radially from a hub (4) rotatable about a main axis (3), each blade (2) further being pivotable about its radial axis to vary the blade pitch. The blades (2) each are mounted on an associated bearing (5) mounted on said hub, the bearing comprising a ball bearing having a first radially inner race (25) fast the blade (2) and a second radially outer race (26) rotationally fast to the hub (4). The balls (14) in the bearing are separated by separators (15), each separator being generally cylindrical and having its cylindrical axis coaxial with the orbital axis (22) of the orbit of the balls (14) and being adapted to rotate about the said orbital axis (22), the side faces of the separator each having a part spherical recess (16) adapted to receive a ball (14). Rotation of the separator (15) about the orbital axis (22) is such as to entrain lubricant in the bearing and to bias the lubricant from adjacent the outer race (26) over the balls (14) towards the inner race (25).

An outer ring case includes an annular guide groove housing an end of each of a plurality of inner rollers. A groove width representing a radial length of the guide groove is greater than a diameter of each inner roller. A radius representing a distance from a bearing axis to an inner wall face of the guide groove that is radially outer is smaller than a distance from the bearing axis to an axial center of each of rollers plus a radius of each inner roller.

An outer ring case includes an annular guide groove housing an end of each of a plurality of inner rollers. A groove width representing a radial length of the guide groove is greater than a diameter of each inner roller. A radius representing a distance from a bearing axis to an inner wall face of the guide groove that is radially outer is smaller than a distance from the bearing axis to an axial center of each of rollers plus a radius of each inner roller.

Provided herein are robotic systems, for example, MRI guided robots, for image-guided robot-assisted surgical procedures and methods for using the same to perform such surgical procedures on a patient. The robotic systems comprise a robotic manipulator device or global positioner, means for actuating the robotic manipulator or global positioner that is mechanically linked thereto and a computer having a memory, a processor and at least one network connection in electronic communication with the robotic system. The actuating means comprises at least one transmission line having a flexible component comprising a displaceable medium, a rigid component comprising rigid pistons or a combination through which actuation is transmitted to the robotic manipulator or global positioner. The computer tangibly stores in memory software modules comprising processor-executable instructions to provide interfaces between the robotic system, an imaging system and an operator and to control operation thereof.

Described herein is a rolling bearing having two concentric raceways between which there are provided, in a bearing gap, a plurality of rolling bodies which roll on at least two tracks, wherein intermediate pieces which keep the rolling bodies spaced apart from one another are provided between the rolling bodies, wherein the intermediate pieces each comprise a central portion which is connected via connecting struts to an outer frame part surrounding the central portion, wherein the frame part takes the form of a bar structure or skeleton structure with window-like and/or door arch-like cutouts.