A sensorized rolling element for a bearing having inner and outer races and a plurality of rolling elements disposed between the inner and outer races and includes a rolling element body having an interior surface defining a cavity, the body being disposable between the inner race and the outer race. A wireless transmitter is disposed within the cavity of the rolling element body and a piezoelectric device is disposed within the cavity so as to contact the inner surface of the rolling element body. The piezoelectric device includes a body formed of piezoelectric material and at least two electrodes electrically coupling the piezoelectric body with the wireless transmitter. The piezoelectric device is configured to generate electrical charge for powering the transmitter when the rolling element body deflects under loading applied by the inner race and/or outer race and may also be used to detect loading on the rolling element body.

A rolling bearing makes use of a porous rolling element and a selected kind of lubricant to impregnate with; is usable in various conditions; does not discharge foreign objects; and features low dust generation and long life. The rolling bearing includes an outer ring 2; an inner ring 1; and a plurality of rolling elements 3 assembled between mutually opposed outer ring track surface 2a and inner ring track surface 1a. The plurality of rolling elements 3 is provided by a combination of a porous rolling element 3a impregnated with a lubricant and a non-porous rolling element 3b.

A force-transmitting assembly includes a metal shaft having at least two longitudinally-extending grooves defined in an outer surface, and a metal hub having at least two longitudinally-extending grooves defined in an inner surface that surrounds the outer surface of the shaft. A plurality of discrete parts is disposed in the at least two longitudinally-extending grooves of the shaft and the hub in an interference-fit manner so as to transmit a torque from the shaft to the hub. Each of the discrete parts is composed of at least 50 mass % of technical ceramic selected from Si.sub.3N.sub.4, SiAlON, Al.sub.2O.sub.3, ZrO.sub.2, or a mixture of two or more of Si.sub.3N.sub.4, SiAlON, Al.sub.2O.sub.3, and ZrO.sub.2.

A process for determining the reliability of a sensorized bearing configured to measure load and speed is provided. The process includes the following steps. Bearing load and rotational speed are determined from data acquired from the sensorized bearing. Next, an array linking the determined load to the determined n.dm value is filled until that all available loads are parsed. Then a L10 life is determined for each load within a distribution based on the array. Finally, an overall L10 life is determined based on the Palmgren-Minor rule. The load distribution and the L10 lives a bearing reliability R for a given date is determined based on a Weibull curve and the overall L10 life.

This invention relates to a bearing monitoring method and system suitable for the monitoring of faults in rolling element bearings. The method and system utilize an acceleration sensor that is sensitive to both acceleration and housing strain and which has the effect of amplifying acceleration events that coincide with areas of the housing strain signal that correspond to bearing ball-pass events. The housing strain signal due to ball-pass events can be used to synchronise or otherwise modify the sampling of acceleration signals, or to determine bearing performance characteristics.

This invention relates to a bearing monitoring method and system suitable for the monitoring of faults in rolling element bearings. The method and system utilize an acceleration sensor that is sensitive to both acceleration and housing strain and which has the effect of amplifying acceleration events that coincide with areas of the housing strain signal that correspond to bearing ball-pass events. The housing strain signal due to ball-pass events can be used to synchronise or otherwise modify the sampling of acceleration signals, or to determine bearing performance characteristics.

A generatrix shape to which crowning is applied includes a first generatrix shape which is formed in a central portion in an axial direction of at least one of an outer ring raceway surface, an inner ring raceway surface, and a rolling surface of a roller and is composed of a straight line, a pair of second generatrix shapes which are formed from both ends in the axial direction toward the outside in the axial direction of the first generatrix shape and are composed of a single arc curve, and a pair of third generatrix shapes which are formed from both ends in the axial direction toward the outside in the axial direction of the second generatrix shape and are composed of a composite curve of a single arc curve and a logarithmic curve.

A generatrix shape to which crowning is applied includes a first generatrix shape which is formed in a central portion in an axial direction of at least one of an outer ring raceway surface, an inner ring raceway surface, and a rolling surface of a roller and is composed of a straight line, a pair of second generatrix shapes which are formed from both ends in the axial direction toward the outside in the axial direction of the first generatrix shape and are composed of a single arc curve, and a pair of third generatrix shapes which are formed from both ends in the axial direction toward the outside in the axial direction of the second generatrix shape and are composed of a composite curve of a single arc curve and a logarithmic curve.

A silicon nitride sintered body includes at least one black portion with a major axis of 10 μm or more in a field of view with a unit area of 5 mm×5 mm, when observing an arbitrary cross-section of the silicon nitride sintered body using a metallurgical microscope. A major axis of the black portion is Preferably 500 μm or less. The number of the black portion within the field of view with a unit area of 5 mm×5 mm is preferably 2 or more and 10 or less. A segregation portion of Fe is preferably included in the black portion.

A roller hydraulic valve lifter includes a body having a longitudinal central axis and an interior area defined by an inside surface which has a pair of flat surfaces opposite one another and connected by a pair of walls. A first bore, essentially perpendicular to the longitudinal axis, extends through the flat surfaces. A bearing is disposed partially in the interior area. The bearing includes an outer ring having substantially cylindrical exterior and interior bearing surfaces. A shaft extends through the first bore and the outer ring and between the pair of flat surfaces. A plurality of needle rollers is disposed between and rollingly engage the shaft and the cylindrical inner bearing surface. The shaft and the plurality of needle rollers are manufactured from an AISI 52100 alloy steel that is carbo-nitrided. The shaft and the plurality of needle rollers have a surface hardness of a minimum of HRc 65.