Abstract: A bearing failure detector for an electrical generator includes a disc located within the bearing assembly near the location of the main bearings. The disc has a central opening through which the shaft extends, and the disc includes a thin, electrically conductive ring which is plated or formed as a film inside the central opening. The ring is exposed to the shaft along inside diameter of the detector disc adjacent to the periphery of the shaft, but a gap is normally provided around the shaft when the shaft is properly supported by the main bearings, so that the shaft does not contact the ring unless the bearings are significantly worn. The ring provides a closed circuit, and it is connected to a control circuit which monitors the closed circuit at all times. When the internal clearance of the main bearings has been enlarged by a predetermined amount, the ring contacts the shaft, causing the thin ring to be quickly worn away.

Abstract: A method and apparatus for monitoring the condition of an oil lubricated bearing based on the phenomenon that the bearing will operate at a reduced temperature for a limited time period after losing its flow of lubricating oil. The invention includes steps and means for comparing the bearing temperature to an average of similar bearing temperatures, and for generating a low temperature alarm when the bearing temperature drops more than a threshold amount. The setpoint of this threshold may be a function of the standard deviation of the temperatures of a plurality of similar bearings. The invention may include steps and apparatus for generating a high bearing temperature alarm and for communicating data to a remote location.

Abstract: Axial bearing wear in a motor is determined by differencing signals from special coils in the two ends of the motor stator. The signals on the two coils vary in opposite directions with axial displacement of the motor rotor. A dead zone circuit suppresses output when the axial displacement of the rotor is within the normal range of play for the rotor of the particular motor. When the axial displacement exceeds the normal range, the output actuates an indicator in relation to the magnitude of the displacement in excess of the normal range. Sequential LED indicators indicate both magnitude and direction of excess displacement. An analog meter is also disclosed which indicates only the magnitude of the excess displacement.

Abstract: The present invention provides a method for constant and rapid heat dissipation and thermal indication for railway wheel set assemblies. The method comprises assembling a vehicle wheel set by mounting bearings and wheels on an axle with interference fit and mounting bearing adapter onto bearings. Heat pipes are embedded within the said vehicle wheel set. The heat pipes provide heat sinks for the vehicle wheel set assembly causing a fluid within the heat pipe to vaporize on sections of heat pipe more adjacent to the bearing assemblies and to condense on other sections of heat pipes more adjacent to the heat dissipation areas. The heat dissipation area can be either the surfaces of the wheel set assembly or the surfaces of additional cooling fins mounted on the wheel set assembly. The embedment of heat pipes within the wheel set assembly thus enables constant cooling for bearing assembly.

Abstract: A process is disclosed for the automated diagnosis of monitored objects, especially of drive strings, with a stationary, fully automatically operating data collecting unit positioned on the monitored object and a monitoring terminal spatially separated therefrom, whereby the quantitative description of the damage condition and therefore the activation of data transfer and subsequent reporting of diagnosis statements at the monitoring terminal is triggered by the significance of a damage property correspondingly weighted by the damage type, or a combination of different damage properties, which are specified by the amplitude of the physical variable corresponding to the kinetic occurrences which are formed for the harmonic excitation within the spectrum of the wide band signal detected by way of sensors at the machine surface, or for the impact impulse type excitation of the high pass filtered envelope curve spectrum of the same signal, or for the discontinuously appearing determinant impulse excitation from t

Abstract: A system for qualifying and monitoring bearing performance and condition in a rotary servo system. A position error signal is analyzed for signal anomalies that can signify bearing damage. A DC offset ramp is applied to the position error signal to test whether the anomaly is angular position dependent. The anomaly is associated with the corresponding command signal value and range of values to calculate the angular position and range of the apparent bearing damage. The amplitude of the anomaly is measured and associated with a relative degree of bearing damage.

Abstract: A system for monitoring the operational status of a plurality of mechanical components, such as various bearings, speed reducers and the like. Each of the mechanical devices includes a respective local transmitter in electrical communication with various local sensors. Among the sensors which may be utilized are a temperature sensor and a shaft speed sensor, as well and an accelerometer for detecting vibration. The local transmitter receives information from the sensors and provides status information in a predetermined output format, such as a serial digital format. Unique electronic identifiers are assigned to respective of the local transmitters to facilitate selective communication with a central monitoring processor. As a result, the status information will be supplied to the central monitoring processor at predetermined times.

Abstract: It is possible to monitor the performance of a lubrication system performance of a Dynamoelectric Machine (DEM) by observing the electric current flowing in the DEM shaft. Suitable Rogowski coils are mounted around the shaft of the rotor of a DEM just inboard the bearings. The Rogowski coil may be mounted on the shaft to rotate with the shaft, or it may be mounted on said DEM so as to surround the shaft and remain stationary. Shaft current magnitudes may be established for start-up and steady state operating conditions. Any deviation from the steady state shaft current magnitude may be taken as a warning that the DEM bearing lubrication system is malfunctioning.

Abstract: Described is a device (10) for monitoring bearing performance in apparatus having an aperture sized and configured to receive a grease fitting. The device includes temperature sensing components (34) or vibration sensing components (36), or both, to enable detection of impending bearing failure, and is adapted to either replace or supplement conventional grease fittings (28). The device is configured so as to cooperate with bearings housings of widely divergent dimensions, and in each case to permit adjustment of the device, including the sensing components thereof, to place it in very close proximity to the bearing.

Abstract: A vibration sensor includes a housing having an opening, and a movable trigger retained within the housing by a resilient member. The moveable trigger includes a projection of a dimension to fit at least partially through the opening. The resilient member retains the movable trigger within the housing until overcome by a predetermined acceleration. Whereas the moveable trigger is maintained within the housing the vibration sensor is minimally affected by radial acceleration while providing a calibrated resistance which must be overcome by an acceleration of predetermined severity along the measured direction. When the sensor experiences a predetermined acceleration, the trigger slides within the housing until the projection encounters the opening. The projection then “pops” through the opening such that the projection encounters a switch which awakes and activates a transmitter to send a signal to a warning device.

Abstract: Devices for monitoring bearing performance in apparatus having an aperture sized and configured to receive a grease fitting. The devices comprise a temperature sensor or a vibration sensor, or both, to enable detection of impending bearing failure, and further comprise rigidly attached electronic components which amplify signals generated by the temperature sensor and/or vibration sensor. The devices may be adapted to either replace or supplement conventional grease fittings, and enable the transmission of electronic signals which may be used for constant monitoring of critical equipment. Bearing housings which incorporate these features, as well as subassemblies and related methods, are also described.

Abstract: A drive line vibration sensor includes a mercury switch, a controller, and a warning device. The mercury switch is preferably positioned such that it is minimally affected by radial acceleration yet remains sensitive to longitudinal accelerations along the longitudinal axis of a drive line. To minimize the affect of radial acceleration, the mercury switch is attached to the drive line such that the mercury switch is tilted relative to the longitudinal axis such that the radial acceleration of the drive line does not activate the mercury switch. If the mercury switch experiences a predetermined acceleration, the controller identifies that the mercury switch is activated and the controller then awakes and activates a transmitter, such as a radio frequency (RF) transmitter to send a signal to a remote warning device such as a warning light.

Abstract: A motor is provided in which zero-point positioning of the stator and rotor in the axial direction is simple. The operation of replacing the rotor or stator can be done easily. A motor is provided in which zero-point positioning of the stator and rotor in the axial direction is simple and the detection precision can be improved. In a canned motor, a bearing wear monitoring device monitors the wear of the bearings that supports the rotor. The wear of the bearings is determined by measuring the displacement of the rotor based on the output signal of detection coils that are provided in embedding core units on both axial ends of the stator. The center of the embedding core unit at one axial end of the stator and the end face of one axial end of the stator are positioned to coincide with one another. The other axial end of the rotor is made to protrude outside the embedding core unit of the other axial end of the stator by a prescribed dimension.

Abstract: A bearing detection system for an electrical generator (10) includes auxiliary bearings (29) for supporting a rotating shaft (39) upon failure of main bearings (62). The auxiliary bearings (29) are mounted on the shaft and have a slight gap (64) between their outside diameters and bearing liners 33. The gap corresponds to the main bearing permissible wear. During normal functioning of the main bearing, the auxiliary bearing frame (34) rotates with the shaft and a magnet (35) with a small clearance between its face and auxiliary bearing outer ring (32) forces the synchronized rotation of inner (37) and outer (32) races. The auxiliary bearing outer ring or race (32) has a coaxial groove (31) on its outer diameter and a detection sensor (30), mounted on the bearing liner, gives a signal per rotation of the shaft to a control circuit (40).

Abstract: The present invention provides a system and method for monitoring an electrical signal appearing on a rotating machine shaft. The system comprises a probe assembly for placement against the rotating machine shaft that is in electrically conductive contact with the shaft. The probe assembly includes at least one circuit for receiving the electrical signal from the rotating machine shaft and producing various electrical signals that are read by a data processing system, which is coupled to the circuit. The data processing system determines from the electrical signal obtained from the circuit, the RMS AC voltage, DC voltage, peak voltage, and the RMS AC and DC current through two different resisters that are all appearing on the rotating machine shaft. The data processing system also performs Fast Fourier Transforms on the RMS voltage and current signals and produces a frequency spectrum over time.

Abstract: Fiber optic filaments are embedded at a bearing surface. In the context of a mechanical bearing system, the filaments wear as the surface wears. Based on the observed amount of light which is transmitted through the filaments, the degradation of the filaments is related in a measurable way to the wear of the bearing surface. The sole power requisite for inventive operation is light, for observation purposes. As compared with convention approaches to wear measurement, the invention more accurately measures wear of the bearing itself and is therefore a better predictor of servicing requirements. Inventive practice of remote wear monitoring is a viable and preferable option.

Abstract: A ring-shaped bearing failure sensor constructed of insulation and electrically conductive material utilizing printed circuit board technology. Because of its construction, high dimensional tolerances can be achieved and the ring can be easily assembled as a component of a generator. Further, the bearing sensor is equipped with a resistor so that the operational readiness of the sensor can be monitored.

Abstract: A bearing is mounted within a housing having an acoustic-electric transducer mounted on its outside. A stationary annular outer race has at least one sensor, an electric-acoustic transducer, and an electronic system interconnecting the sensor and the electric-acoustic transducer. The electric-acoustic transducer is mounted in an opening extending radially through the stationary race. The electric-acoustic transducer has an elastic cap pressed into the inside of the housing by a spring. An alternative configuration, having at least one sensor mounted on a rotatable inner race, without a hard-wired connection through the bearing housing, is also disclosed.

Abstract: The axial bearing includes a first ring and a second ring. During operation of the axial bearing, the first ring rotates with respect to the second ring. Over time the foregoing rotation produces wear of the first ring; consequently, exposes layers of the first ring to the second ring. The different layers of the first ring produce variations in the coefficient of friction within the axial bearing. If the axial bearing is associated with a drive motor, then the variations in the coefficient of friction change the load on the drive motor. The change in load upon the drive motor may be monitored to indicate axial bearing wear or the need for axial bearing replacement.

Abstract: A vibration sensing apparatus including an acceleration sensor 2 for outputting a sensing signal corresponding to a vibrating acceleration, a level discriminator 3 for generating an output when the output level of the signal from the acceleration sensor 2 exceeds a preset reference level, a display unit 4 for displaying the output of the level discriminator 3, a piezoelectric ceramic power generating unit 5 using piezoelectric ceramics for generating a charge when it is subjected to vibration, and a conversion unit 6 for converting the charge generated by the piezoelectric ceramic power generating unit 5 into DC power, the DC power being supplied to the level discriminator and to the display unit as power to be consumed by them.

Abstract: A bearing liner between inner and outer bearing rings, one stationary and the other rotatable, is fixed to the stationary bearing ring. A pair of electrical conductors, coiled in at least one loop encircling the inner bearing ring, is embedded within the bearing liner. The electrical conductors are electrically isolated and located such that wear of the bearing liner causes the rotatable bearing ring to contact and electrically connect the electrical conductors. An electrical circuit detects the electrical connection to indicate wear of the bearing liner.

Abstract: Described is a device for monitoring bearing performance in apparatus having an aperture sized and configured to receive a grease fitting. The device includes a temperature sensing component or a vibration sensing components, or both, to enable detection of impending bearing failure, and is adapted to either replace or supplement conventional grease fittings.

Abstract: An in-use rolling element bearing monitoring system which uses a piezoelectric film transducer on either a bearing, bearing support structure, or on a separate washer in close proximity to a bearing for monitoring bearing performance. One embodiment provides a bearing monitoring system for detecting and predicting bearing failure. Another embodiment provides a system configured for detecting rotational speed of a rolling element bearing. Each embodiment of the invention entails maintaining a piezoelectric film transducer in contiguous pressure wave responsive communication with a bearing for detecting bearing performance, and provides the system in a compact configuration for in-use operation on a variety of machinery and vehicle components heretofore previously not compatible.

Abstract: A temperature sensor is mounted on the inside surface of a stationary race around which a rotatable race rotates. Electric signals from the temperature sensor are converted into acoustic signals. Without the use of any hard wires, the acoustic signals are received by an acoustic-electric transducer mounted on the outside surface of the bearing housing. These electric signals from the acoustic-electric transducer are frequency demodulated and converted into signals which indicate on a display panel the temperatures within the bearing.

Abstract: A thermal warning device attaches to a wheel assembly of a railway car to detect whether the wheel assembly has reached high temperatures and may lead to a potential bearing failure. A temperature sensor for monitoring the temperature of the wheel assembly is coupled to an electronic circuit for determining whether a bearing failure may occur based on the temperatures detected by the temperature sensor. In particular, the temperature sensor adjustably extends into the wheel assembly in order to obtain accurate readings of high temperatures in wheel assembly. Also, the electronic circuit is situated away from the outer surface of the wheel assembly so that the electronic circuit will not be subjected to heat from the wheel assembly and may freely dissipate heat produced by its own components. Upon determination of a warning condition, the electronic circuit transmits a warning signal to a wayside station or train crew.

Abstract: A bearing failure detector for an electrical generator includes a disc located within the bearing assembly near the location of the main bearings. The disc includes an electrically conductive ring encased in an insulation layer. The ring is exposed along inside diameter of the detector disc adjacent to the periphery of the shaft, but the dimensions of the inside diameter of the ring are slightly greater than the normal internal clearance of the main bearings, so that the shaft does not contact the ring unless the bearings are significantly worn. The detector ring is connected to a resistor with a large resistance which is monitored by a control circuit at all times. When the internal clearance of the main bearings has been enlarged by a predetermined amount, the ring contacts the shaft, changing the resistance monitored by the control circuit. This causes the control circuit to provide an indication that the bearings need replacement.

Abstract: A bearing is mounted within a housing having an acoustic-electric transducer mounted on its outside. A stationary annular outer race has at least one sensor, an electric-acoustic transducer, and an electronic system interconnecting the sensor and the electric-acoustic transducer. The electric-acoustic transducer is mounted in an opening extending radially through the stationary race. The electric-acoustic transducer has an elastic cap pressed into the inside of the housing by a spring.

Abstract: The axial bearing includes a first ring and a second ring. During operation of the axial bearing, the first ring rotates with respect to the second ring. Over time the foregoing rotation produces wear of the first ring; consequently, exposes layers of the first ring to the second ring. The different layers of the first ring produce variations in the coefficient of friction within the axial bearing. If the axial bearing is associated with a drive motor, then the variations in the coefficient of friction change the load on the drive motor. The change in load upon the drive motor may be monitored to indicate axial bearing wear or the need for axial bearing replacement.

Abstract: Bearing assembly including at least one proximity probe for monitoring the relative vibration of a rotating shaft contained therein. The bearing assembly includes a bearing housing surrounding and supporting a cylindrical shell. The cylindrical shell defines a shaft bore for receiving a rotating shaft. At least one proximity probe is embedded in the cylindrical shell for monitoring the shaft vibration. A second proximity probe may be added to enable monitoring radial shaft position. The proximity probes are connected to an instrument or instruments for displaying a signal received from the probes for allowing a user to determine shaft vibration or position.

Abstract: A temperature measuring system is described which is activated in response to the occurrence of detecting a temperature greater than a predefined critical temperature which includes a transceiver which receives an incoming electromagnetic wave, a temperature sensing means, e.g. a gas thermometer to measure the temperature of the desired component, and an electromagnetically interrogatable transponder chip capable of selectively transitioning from an inactive state to an active state upon the temperature exceeding the predefined critical temperature. The transponder chip when in the active state, converts the electromagnetic wave to a surface acoustic wave which passes over the transponder chip and upon exiting from the transponder chip is reconverted to an electromagnetic wave which is slightly modified from the incoming electromagnetic wave.

Abstract: An on-board hot bearing detector system includes a microprocessor and heat sensors mounted on the train cars for sensing the bearing temperatures. Diagnostic circuitry is also provided to monitor the sensors and detect if a sensor is open or short. Additionally, the train line is controlled by the microprocessor and is provided with a current limiting device for protection against large currents in case of a short.

Abstract: A frequency generating circuit and a cap-freeing mechanism in a bolt are responsive to a longitudinal movement of a piston in response to overheating of an associated bearing. The cap-freeing mechanism transfers a force from the piston to a cap, thereby freeing the cap from a head portion of the bolt and allowing an antenna to extend to the outside of the bolt. The frequency generating circuit is activated by a connection made between a switch and a battery of the circuit by the piston. Upon becoming activated, the frequency generating circuit sends a predetermined frequency or frequency pattern through the antenna.

Abstract: A train analysis system for analyzing a wheel condition such as wheel bearing temperature includes circuitry for identifying the wheels of a railroad car, circuitry for averaging the condition of each wheel of a car, and circuitry for establishing a threshold level for said condition, dependent on said averaging. When a wheel cannot be identified, a threshold level is set which is below the maximum level for identified wheels.

Abstract: A bearing assembly monitoring system provides continuous, real time monitoring of the operating condition of a powertrain support bearing assembly and real time alarm signals indicative of degradation and/or impending catastrophic failure thereof. One embodiment of the monitoring system includes a vibration sensing device, first and second primary temperature sensing devices, an ambient temperature sensing device, vibration and temperature signal processing subcircuits, and an alarm subsystem. The vibration sensing device monitors complex vibration signals emanating from the bearing assembly and provides signals corresponding thereto. The vibration signal processing circuit filters such complex vibration signals to provide a predetermined bandwidth thereof that are converted to stabilized DC voltage signals which are compared to reference voltages corresponding to higher than normal and excessive vibration levels. Exceedance of such reference voltages generates a corresponding vibration alarm signal.

Abstract: A communication system for submitting RF signals responsive to the currents of defects or hazards in a railway system wherein a reserve cell ampule containing an electrolyte is disposed in one compartment of a housing and the electronic apparatus transmitting desired signals is disposed in a second compartment such that when the reserve cell is heated the pressure rises within the ampule to rupture it, whereby the electrolyte contained is dispersed in the first compartment and causes energization of electronic apparatus including an antenna connected to such apparatus, whereby the antenna is ejected from the housing and is able to broadcast suitable RF signals.

Abstract: A device for monitoring vibration of a bearing to assess whether other service is required. The device is adaptable for use with conventional grease guns and can be used simultaneously with lubrication of a bearing. The device includes an electric circuit and headphones which enable the wearer to "listen" to the bearing. Depending on the "bearing noise" that is heard, maintenance personnel can assess what further lubrication is required and what service is needed.

Abstract: An apparatus is provided for monitoring a rotor mounted for rotation by bearings within a stationary housing of an apparatus, such as a sealless pump. In a first embodiment, the monitoring apparatus includes at least one magnet mounted on the circumference of the rotor and a plurality of hall effect devices which sense magnetic flux density as the rotor rotates to generate signals representative of radial and axial bearing wear as well as signals representative of the direction of rotation of the rotor. In a further embodiment, the monitoring apparatus includes magnetic material mounted in one or more locations around the rotor or entirely around the rotor and a plurality of hall effect devices and associated magnets mounted within the stationary housing and surrounding the rotor.

Abstract: A temperature sensor assembly for monitoring railroad car wheels includes an array of temperature detectors arranged to generate a temperature profile of the wheel. The array may be formed integrally with imaging elements and signal conditioning elements on a single IC chip. The assembly may be arranged to monitor the wheel either transversely or in parallel to the direction of wheel movement.

Abstract: The present invention relates to a device for detecting, in a machine, the position of contact of two rollers of parallel axes of which at least one is mounted mobile. This device is characterized in that it comprises an elastic member mounted so as to undergo, during contacting of the two rollers, a deformation, limited by a bearing, further to the relative displacement of two elements mobile with respect to each other, and means for measuring this deformation.

Abstract: An apparatus for detecting machining conditions in a machine tool has a magnetic bearing for magnetically supporting a work spindle or a tool spindle. An exciting current detector is provided for detecting an exciting current of an electromagnet of the magnetic bearing. The exciting current corresponds to various machining conditions including the conditions when the machine tool starts operating, the tool contacts the workpiece to follow various unfinished faces, and a machining face condition of the workpiece during machining. The detection signals from the exciting current detector are inputted to a plurality of frequency band pass filters to discriminate the machining conditions. Comparators are provided to compare the output signals from the frequency band pass filters with a predetermined set of reference values, and comparative judgment signals are inputted to a control unit, thereby controlling the machine tool to automatically perform appropriate machining operations.

Abstract: The present invention relates to bearing defect detectors and in particular to an acoustic system for detecting defects in the bearings of moving railroad cars and identifying the location of these defects.

Abstract: Overheated railroad journal bearings, wheels, and other wheel components on a moving or stationary railroad train are detected by amplifying the current signal from an infrared radiation sensor comprising a pytoelectric cell. A reference temperature is sensed by chopping the incident infrared radiation with an asynchronous shutter that momentarilly closes at successive time spacings of shorter duration than the scanning period of the sensor. The amplified signal is converted to a digital signal and processed by a microcontroller and associated hardware and software. The detector automatically and periodically calibrates itself and compensates the temperature signals for any temperature difference between the ambient external temperature and the temperature inside the detector housing. The output signal may be digital or analog.

Abstract: A method for predicting destruction of a bearing preliminarily finds frequency range of acoustic emission signals indicating fatigue of bearings. In order to find the fatigue-related frequency range, frequency components of electrical noise, mechanical noise, acoustic emissions (AE) due to slip of a bearing, and AE due to plastic-deformation of the bearing are respectively obtained under corresponding conditions, using a test equipment. Then, under a certain condition, combined AE signals of electrical noise, mechanical noise, slip-related AE, plastic-deformation-related AE and rolling-fatigue-related AE are generated. By subtracting the frequency components of electrical noise, mechanical noise, slip-related AE, plastic-deformation-related AE from frequency components of the combined AE signals, the fatigue-related frequency range is obtained. This frequency range is used to predict destruction of a bearing.

Abstract: A pump shut-down system is disclosed for preventing damage to the pump from bearing failure. That system has a metal bar located within a preset clearance distance from a traveling element of the pump (such as a piston rod), a voltage source in electrical contact with the metal bar, an automatic shut-down relay in electrical contact with the voltage source, and an electrical ground on the pump in electrical contact with the voltage source. The metal bar, voltage source, automatic shut-down relay, and electrical ground all form an electrical circuit. That circuit is open when the metal bar is not in physical contact with the traveling element, and is closed whenever the metal bar is in physical contact with the traveling element. Whenever the circuit is closed, the automatic shut-down relay shuts down the pump.

Abstract: Overheated railroad journal bearings, wheels, and other wheel components on a moving or stationary railroad train are detected by amplifying the current signal from an infrared radiation sensor comprising a pyroelectric cell. A reference temperature is sensed by chopping the incident infrared radiation with an asynchronous shutter that momentarily closes at successive time spacings of shorter duration than the scanning period of the sensor. The amplified signal is converted to a digital signal and processed by a microcontroller and associated hardware and software. The detector automatically and periodically calibrates itself and compensates the temperature signals for any temperature difference between the ambient external temperature and the temperature inside the detector housing. The output signal may be digital or analog.

Abstract: In a process for early detection of damage top machine parts, particularly rolling element bearings, vibrations are detected by means of a vibration pickup in order to make it possible to describe the present condition of the machine part as well as to estimate the remaining service life of the machine part. The picked-up signals are broken down into periodically determined stochastic and generally stochastic signal components. The signal components for determining the parameters for the stress of the machine part are examined as a function of time and the ascertained stress parameters are compared with characteristics values for the permissible stress of the machine part for purposes of determining the type of damage and/or for determining the extent of the damage.

Abstract: A shear detection circuit includes a resistive element in series with another resistor for providing an electrical signal at a node proportional at the value of the resistors when a voltage potential is applied to the detection circuit. The electrical signal is compared to a known value to permit detection of a severed shear pin or an open or short circuit in the detection circuit. The electrical signal is monitored by a computer for displaying the status of the shear pin and the detector circuit and for storing the status of the shear pin and the shear detection circuit for maintenance or repair.

Abstract: Method for predicting destruction of a rolling bearing using an apparatus which has a sensor for detecting acoustic emission signals from a rolling bearing, a plurality of band-pass filters which have different specific frequency pass bands within the range of 150-400 KHz, first comparators for comparing outputs from the band-pass filters with their respective reference values for the specific frequency bands, time-measuring devices for measuring time during which the outputs from the band-pass filters exceed the reference values, and second comparators for comparing the time measured with a further reference value. Of all signals detected by the sensor, only those that have frequencies of 150-400 KHz pass the corresponding band-pass filters, and then are compared with their respective reference values. The first comparators signal to the time-measuring devices when the outputs from the band-pass filters exceed the reference values.

Abstract: A bearing unit has a sensor for sensing rotating speed of a wheel. A concave or a convex portion is formed on an end surface of a wheel shaft rotating with a rotating inner ring member. A disk-like sensor rotor forms on its center a convex or a concave portion which is fit to said concave or convex portion of the wheel shaft.A sensor is attached to a lid body covering an end portion opening of an outer ring member. Install length of the sensor rotor becomes small so that the length of the entire bearing unit becomes small.

Abstract: Auto-correlation techniques are employed to monitor railway care wheel bearings. Three successive bearing temperatures A, B and C are measured and those two temperatures that are the closest in value determined. The least of these is used as a reference to be multiplied by a constant and thereby define a limit value which when exceeded generates an alarm signal.