Abstract: A deep groove ball bearing providing an inner ring, an outer ring and a plurality of balls being arranged between the inner ring and the outer ring. The inner ring and the outer ring each include a raceway for the plurality of balls. Each raceway encompasses the plurality of balls symmetrically. The deep groove ball bearing is lubricated by a lubricant being arranged on each axial side of the plurality of balls. The raceways are offset in the same axial direction from the axial center of the inner ring and the outer ring such that the raceways are offset to the axial side of the deep groove ball bearing where the shear rate acting on the lubricant is higher than on the other axial side of the deep groove ball bearing.

Abstract: Disclosed is a monitoring method for monitoring the film thickness of a lubricant within a lubricated bearing, the bearing having an inner ring, an outer ring and rolling elements being arranged between the inner ring and the outer ring/ The monitoring method comprises a capacitance measuring step for measuring the total capacitance of the bearing; a first calculation step for determining a film thickness of the lubricant based on the measured capacitance of the bearing and for determining whether the lubrication condition is fully flooded or starved, and when the lubrication condition is fully flooded, a second calculation step for correcting the film thickness determined in the first calculation step.

Abstract: System for determining rheological properties of grease, includes a grease worker having a cylinder intended to contain the grease and a piston intended to move inside the cylinder in a first direction and in a second opposite direction and provided with holes. The grease worker further including a seal provided between the piston and the cylinder, force for measuring the force required to push the grease through the holes of the piston is measured an electrical motor and an eccentrical connection transforming the rotating motion of the motor in a translation motion pushes the grease thought the holes, a thermocouple for measuring a temperature of the cylinder, a fan and a heater for regulating temperature for maintaining constant the measured temperature at a predetermined temperature, and a computing unit configured to determine at least one rheological property of the grease from the measured forces and from the seal friction.

Abstract: A rolling bearing arrangement having a first and a second raceway element, and rolling bodies being arranged between the two raceway elements so that the two raceway elements are rotatable against each other in the manner of a rolling bearing, a space between the raceway elements in which the rolling bodies are rolling off comprising a lubricating grease, at least one sensor element for sensing temperature, at a specific point of the rolling bearing, particularly in the space, and for sensing speed of the rolling bearing and a unit receiving the sensed temperature and speed, calculating from the profiles of the sensed temperature over time and from the speed over time via a calculated energy imposed on the grease a used and/or remaining period of the grease life-time.

Abstract: A deep groove ball bearing providing an inner ring, an outer ring and a plurality of balls being arranged between the inner ring and the outer ring. The inner ring and the outer ring each include a raceway for the plurality of balls. Each raceway encompasses the plurality of balls symmetrically. The deep groove ball bearing is lubricated by a lubricant being arranged on each axial side of the plurality of balls. The raceways are offset in the same axial direction from the axial center of the inner ring and the outer ring such that the raceways are offset to the axial side of the deep groove ball bearing where the shear rate acting on the lubricant is higher than on the other axial side of the deep groove ball bearing.

Abstract: A rolling bearing having an inner ring, an outer ring and a plurality of rolling elements being arranged between the inner ring and the outer ring is provided. The inner ring and the outer ring each include a raceway for the plurality of rolling elements. Each raceway encompasses the plurality of rolling elements symmetrically. The rolling bearing further includes an asymmetric cage being arranged between the inner ring and the outer ring for holding the rolling elements. The rolling bearing is lubricated by a lubricant being arranged on each axial side of the plurality of rolling elements. The raceways are offset in the same axial direction from the axial center of the inner ring and the outer ring such that the shear rate acting on the lubricant is equal on each axial side of the rolling bearing.

Abstract: Disclosed is a sealed bearing arrangement that provides at least a bearing with an outer ring and an inner ring, which are rotatable to each other and form a rolling chamber between each other, in which a set of rolling elements. A lubricant is encompassed in the rolling chamber and the rolling chamber is sealed off from an environment by at least one sealing element. The inner ring, the outer ring and/or the sealing element includes at least one opening for providing a fluid passage through the sealing element. The bearing is arranged in a housing that is adapted to seal off the bearing from an outside environment. A lubricant is encompassed inside the housing. The housing including the at least one opening for providing a fluid passage from the inside of the housing to the outside. The opening is fluid tightly connected to an oxygen removing element and/or to a gas tank, which provides an oxygen poor to free fluid flow to the rolling chamber.

Abstract: A rolling bearing arrangement having a first and a second raceway element, and rolling bodies being arranged between the two raceway elements so that the two raceway elements are rotatable against each other in the manner of a rolling bearing, a space between the raceway elements in which the rolling bodies are rolling off comprising a lubricating grease, at least one sensor element for sensing temperature, at a specific point of the rolling bearing, particularly in the space, and for sensing speed of the rolling bearing and a unit receiving the sensed temperature and speed, calculating from the profiles of the sensed temperature over time and from the speed over time via a calculated energy imposed on the grease a used and/or remaining period of the grease life-time.

Abstract: A system for investigating rheological properties of grease, the system including grease sample preparation arrangement for preparing a grease sample with a predetermined quantity of grease, at least two sample holder plates for holding the grease sample by sandwiching the grease sample between the sample holder plates, wherein at least one of the sample holder plates is transparent, and a loading system for generating a predetermined force acting on the grease sample sandwiched between the sample holder plates by pressing on the sample holder plates such that a spot formed by the grease sample on the sample holder plates is expanded. The loading system can include at least one transparent portion enabling a continuous observation of the expansion of the spot while the predetermined force is acting on the grease sample.

Abstract: A system for investigating rheological properties of grease, the system including grease sample preparation arrangement for preparing a grease sample with a predetermined quantity of grease, at least two sample holder plates for holding the grease sample by sandwiching the grease sample between the sample holder plates, wherein at least one of the sample holder plates is transparent, and a loading system for generating a predetermined force acting on the grease sample sandwiched between the sample holder plates by pressing on the sample holder plates such that a spot formed by the grease sample on the sample holder plates is expanded. The loading system can include at least one transparent portion enabling a continuous observation of the expansion of the spot while the predetermined force is acting on the grease sample.

Abstract: The invention relates to a method of predicting when a grease in a grease-lubricated rolling element bearing (10) will reach an unacceptable condition. According to the invention, a time series of a parameter is measured and recorded, whereby the parameter is directly or indirectly indicative of a degree of breakdown of a lubricant film separating the rolling contacts. With the aid of processing means (22), the time series is analyzed, a dynamic model is constructed that predicts the evolution of parameter values, and the model is used to extrapolate the time series. A time at which a predefined limit will be exceeded is then determined from the extrapolated time series, whereby the predefined limit is representative of unacceptable grease condition. The method according to the invention can be used to predict a relubrication interval for an individual grease-lubricated bearing.

Abstract: Method and apparatus are disclosed for measuring an apparent viscosity of a non-Newtonian fluid. The method and apparatus involves calculating a power-law number n relating a shear stress of the fluid to a shear rate of the fluid, and then calculating an estimated apparent viscosity ?est of the fluid at a selected shear rate based on a yield stress Y of the fluid and on the calculated power-law number n. The estimated apparent viscosity of the fluid at a selected shear rate is calculated based on the experimental observation that reference shear stress is 1.5 times the yield stress for most shear thinning fluids (e.g., grease).

Abstract: The invention relates to a method of predicting when a grease in a grease-lubricated rolling element bearing (10) will reach an unacceptable condition. According to the invention, a time series of a parameter is measured and recorded, whereby the parameter is directly or indirectly indicative of a degree of breakdown of a lubricant film separating the rolling contacts. With the aid of processing means (22), the time series is analyzed, a dynamic model is constructed that predicts the evolution of parameter values, and the model is used to extrapolate the time series. A time at which a predefined limit will be exceeded is then determined from the extrapolated time series, whereby the predefined limit is representative of unacceptable grease condition. The method according to the invention can be used to predict a relubrication interval for an individual grease-lubricated bearing.

Abstract: A method for treating the surface of a machine element, such as the raceway and/or a rolling element of a rolling element bearing, comprising the steps of—subjecting the surface to a hard turning operation so as to obtain a specific roughness profile having a series of alternating ridges and grooves, —after the hard turning operation subjecting the surface to a ball calendering operation so as to flatten the ridges of the roughness profile whereby a ?q value smaller than 5° is obtained.

Abstract: A method for lubricating the rolling contacts in a rolling element bearing having at least two rings which are each provided with raceways, as well as a at least one series of rolling elements which are in contact with the raceways, comprises the steps of providing the raceway surface of at least one of the rings and rolling elements with a pattern which has a dominant oblique characteristic in relation to the axis of the bearing, providing a lubricant on the raceway surface, and making the rolling elements overroll over the patterned raceway surface over at least the full circumference of the raceway so as to displace the lubricant in the axial direction under the influence of the engagement of the rolling elements with the pattern.

Abstract: A rolling element bearing comprises an inner ring and an outer ring which are each provided with a raceway, and a series of rolling elements which are in contact with the raceways of each ring. A lubricant film is provided in the contacts between the rolling elements and the raceways, which film forms a lubricant meniscus at the inlet side of each contact. In the bearing starved lubrication conditions prevail. The surface of each rolling element has minute recesses filled with a lubricant quantity, said recesses being flattened in the contact area defined by the contact between the rolling elements and the rings and thereby releasing lubricant at the inlet side of each contact resulting in a displacement of the meniscus further away from said contact. This meniscus displacement results in an increased lubricant film thickness in each contact area, thus improving the lubricating conditions in the bearing.

Abstract: A rolling element bearing comprises an inner ring and an outer ring which are each provided with a raceway, and a series of rolling elements which are in contact with the raceways of each ring. A lubricant film is provided in the contacts between the rolling elements and the raceways, which film forms a lubricant meniscus at the inlet side of each contact. In the bearing starved lubrication conditions prevail. The surface of each rolling element has minute recesses filled with a lubricant quantity, said recesses being flattened in the contact area defined by the contact between the rolling elements and the rings and thereby releasing lubricant at the inlet side of each contact resulting in a displacement of the meniscus further away from said contact. This meniscus displacement results in an increased lubricant film thickness in each contact area, thus improving the lubricating conditions in the bearing.

Abstract: A rolling element having comprises an inner ring, an outer ring and a series of rolling elements which are in contact with the raceways of the rings, an ultra-low viscosity fluid being present in the contacts having a kinematic viscosity ?=(?o/?) of less than 2 mm2/s, wherein the surfaces of the rings and the rolling elements have asperities which can have solid-to-solid contact during operation of the bearing. A factor <i>Dq</i> is defined which is equal to (I) whereby the solid-to-solid contact of the asperities is reduced by selecting such design parameters and operating conditions of the bearing that <i>Dq</i> is in the range from 8.0×10?6 mrad s1/2 to 1.36×10?4 mrad s1/2.

Abstract: A method of manufacturing a roller element bearing comprising an inner ring, an outer ring, and a series of rolling elements. A rolling surface of each rolling element is in contact with a raceway surface formed in each of the inner and the outer rings. At least one of the raceway surfaces of the inner and outer rings and the rolling surfaces of the rolling elements is provided with a topography comprising recesses which are generally isolated by lands. The recesses are formed by shot peening at least one of the surfaces. In addition, the recesses are provided with lubricant.

Abstract: A rolling element having comprises an inner ring, an outer ring and a series of rolling elements which are in contact with the raceways of the rings, an ultra-low viscosity fluid being present in the contacts having a kinematic viscosity &ngr;=(&eegr;o/&rgr;) of less than 2 mm2/s, wherein the surfaces of the rings and the rolling elements have asperities which can have solid-to-solid contact during operation of the bearing. A factor <i>Dq</i> is defined which is equal to (I) whereby the solid-to-solid contact of the asperities is reduced by selecting such design parameters and operating conditions of the bearing that <i>Dq</i> is in the range from 8.0×10−6 mrad s1/2 to 1.36×10−4 mrad s1/2.