A rotary table (1) includes a base body (10), a worm wheel (21), an inner ring (22), a plurality of rolling elements, and a worm screw unit (30). The worm screw unit (30) includes a worm screw (31) held to be rotatable around an axis and having a second gear (31A) meshing with the first gear (215), and a worm screw housing (32) surrounding and holding the worm screw (31) and being fixed to contact the holding surface at a planar contacting surface thereof. One of the holding and contacting surfaces has a cylindrical pin (33) arranged to protrude therefrom. The other of the holding and contacting surfaces has a first recess (11) formed to receive the pin (33), the first recess having a width corresponding to the pin (33) and being elongated in the radial direction of the worm wheel (21).

A method of determining the center of loading of a rolling element includes providing a rolling element body and at least three load sensors. The sensors are each positioned within a bore of the rolling element body at a separate distance from a reference position. Load measurements are taken with each one of the sensors at various positions about the circumference of the bearing and the center of loading is calculated at each one of the positions to determine the variation in axial loading about the bearing circumference.

A method of determining the center of loading of a rolling element includes providing a rolling element body and at least three load sensors. The sensors are each positioned within a bore of the rolling element body at a separate distance from a reference position. Load measurements are taken with each one of the sensors at various positions about the circumference of the bearing and the center of loading is calculated at each one of the positions to determine the variation in axial loading about the bearing circumference.

The present invention resides in a sensorized roller of a roller bearing. The sensorized roller includes a roller bore that accommodates a measuring device for measuring deformation of the roller bore and electronics for processing a deformation signal from the measuring device and wirelessly transmitting the processed deformation signal to an external receiver. According to the invention, the measuring device and electronics are mounted in a rigid housing that is shaped to fit within the roller bore. A radially outer surface of the housing includes at least one aperture associated with the measuring device. Furthermore, the rigid housing is resiliently mounted to the roller bore via first and second sealing elements that enclose a radial gap between a radially inner surface of the roller bore and a radially outer surface of the housing.

To provide a rolling bearing having a hard film on an inner ring raceway surface and an outer ring raceway surface of the rolling bearing that improves peeling resistance of the hard film, shows the original property of the hard film, and suppresses the attackability to a mating material. A rolling bearing 1 has an inner ring 2 having an inner ring raceway surface 2a on an outer circumference, an outer ring 3 having an outer ring raceway surface 3a on an inner circumference, and rolling elements 4 that roll between the inner ring raceway surface 2a and the outer ring raceway surface 3a. A hard film 8 includes a foundation layer formed directly on the inner ring raceway surface 2a or the outer ring raceway surface 3a and mainly formed of Cr and WC, a mixed layer having a gradient composition formed on the foundation layer and mainly formed of WC and DLC, and a surface layer formed on the mixed layer and mainly formed of DLC. In a roughness curve of a surface on which the foundation layer is formed, the arithmetical mean roughness Ra is 0.3 μm or less and the root mean square gradient RΔq is 0.05 or less.

To provide a rolling bearing having a hard film on an inner ring raceway surface and an outer ring raceway surface of the rolling bearing that improves peeling resistance of the hard film, shows the original property of the hard film, and suppresses the attackability to a mating material. A rolling bearing 1 has an inner ring 2 having an inner ring raceway surface 2a on an outer circumference, an outer ring 3 having an outer ring raceway surface 3a on an inner circumference, and rolling elements 4 that roll between the inner ring raceway surface 2a and the outer ring raceway surface 3a. A hard film 8 includes a foundation layer formed directly on the inner ring raceway surface 2a or the outer ring raceway surface 3a and mainly formed of Cr and WC, a mixed layer having a gradient composition formed on the foundation layer and mainly formed of WC and DLC, and a surface layer formed on the mixed layer and mainly formed of DLC. In a roughness curve of a surface on which the foundation layer is formed, the arithmetical mean roughness Ra is 0.3 μm or less and the root mean square gradient RΔq is 0.05 or less.

A rolling bearing is a tapered roller bearing, a cylindrical roller bearing, or a deep groove ball bearing including an inner ring, an outer ring, and a rolling element, each of the inner ring, the outer ring, and the rolling element being composed of a steel, the rolling bearing having a quench-hardened layer in at least one of an inner ring raceway surface of the inner ring, an outer ring raceway surface of the outer ring, and a rolling contact surface of the rolling element. A ratio of a total area of a plurality of martensite crystal grains in the quench-hardened layer is more than or equal to 70%. The plurality of martensite crystal grains are classified into a first group and a second group. An average grain size of the martensite crystal grains belonging to the first group is less than or equal to 0.97 μm.

A rolling bearing is a tapered roller bearing, a cylindrical roller bearing, or a deep groove ball bearing including an inner ring, an outer ring, and a rolling element, each of the inner ring, the outer ring, and the rolling element being composed of a steel, the rolling bearing having a quench-hardened layer in at least one of an inner ring raceway surface of the inner ring, an outer ring raceway surface of the outer ring, and a rolling contact surface of the rolling element. A ratio of a total area of a plurality of martensite crystal grains in the quench-hardened layer is more than or equal to 70%. The plurality of martensite crystal grains are classified into a first group and a second group. An average grain size of the martensite crystal grains belonging to the first group is less than or equal to 0.97 μm.

A bearing rolling element with a lattice internal structure provides several advantages over a solid bearing. It is lighter than a solid bearing, reducing centrifugal forces. For ceramic bearings, less material is required, and sintering times are reduced because bonding material can flow easily to near the surface. Elements with an internal lattice also offer advantages over hollow rolling elements. The shell can be thinner without sacrificing load capacity. The thinner shell reduces the time required for bonding material to be removed during sintering. The blank can be formed using various additive manufacturing processes.

A bearing rolling element with a lattice internal structure provides several advantages over a solid bearing. It is lighter than a solid bearing, reducing centrifugal forces. For ceramic bearings, less material is required, and sintering times are reduced because bonding material can flow easily to near the surface. Elements with an internal lattice also offer advantages over hollow rolling elements. The shell can be thinner without sacrificing load capacity. The thinner shell reduces the time required for bonding material to be removed during sintering. The blank can be formed using various additive manufacturing processes.