Abstract: The invention relates to a hydrodynamic bearing arrangement for an electric motor, particularly for a spindle motor to drive the platters of a hard disk drive. The bearing arrangement comprises a shaft, a bearing bush and a thrust plate disposed fixedly on the shaft, the shaft and the thrust plate rotating with respect to the bearing bush, grooved patterns to generate fluid-dynamic pressure being provided on the thrust plate and/or the surfaces located opposite the thrust plate of the bearing sleeve and/or the cover plate. The grooved pattern comprises a number g of grooves distributed over the surface of the bearing sleeve, the thrust plate or the cover plate, wherein in the shaft and/or in the thrust plate, a number h of holes and/or recesses are provided at the inner edge of the thrust plate and/or at the outer edge of the shaft. According to the invention, the number g of grooves cannot be integrally divided by the number h of holes and likewise that h cannot be integrally divided by g.

Abstract: A method for filling the bearing gap of a hydrodynamic bearing with a lubricant, where drops of lubricant are produced in a defined manner and are applied to a defined region of the bearing to be filled.

Abstract: A fluid dynamic bearing assembly including a shaft and a bearing sleeve. A bearing gap is formed between the shaft and the bearing sleeve and is filled with a lubricating fluid. A capillary seal is formed at one end of the bearing sleeve, and a recess is formed in the shaft immediately above the capillary seal. The surface of the recess forms an acute angle with an axis of the shaft.

Abstract: The method and a device to measure the repeatable and non-repeatable runouts of a rotating component of a spindle motor with the aid of at least one probe measuring changes in the distance between the probe and the rotating component depending on the angle of rotation. The probe records a first test signal in a first test cycle from which a signal defining the RRO is determined and stored. In a second test cycle, a command signal proportional to the amplitude and phase of the RRO signal is generated and fed to an electromechanical actuator supporting the probe. Depending on the command signal derived from the first test signal, the actuator changes the distance between the probe and the outer perimeter of the rotating component, thus compensating the runout defined by the RRO signal, while the probe records a second test signal defining the NRRO.

Abstract: A torque measuring device for electric motors having a rotor and a stator is proposed, said apparatus comprising a holding apparatus to hold the stator non-rotatably, an eddy current brake device which can be used to brake the rotor and a torque sensor connected to the eddy current brake device.

Abstract: A measuring method to determine the noise emission of an electric motor is proposed in which the vibrational excitation of the running electric motor is measured by a laser vibrometer device and this measured vibrational excitation is correlated with a noise level.

Abstract: To provide a measuring method on an electric motor with a rotor and a stator for determining the fly height and/or axial play, the rotor being mounted, and in particular fluid-mounted, on the stator, with which method the axial position of the rotor in relation to the stator can be determined with high levels of accuracy and reproducibility, it is provided that the electric motor is operated at a defined measuring speed, at which the rotor is in a specific axial position in relation to the stator, with this relative axial position being determined in that the rotor is brought in a defined manner, with the motor at a standstill, into a first stop position in relation to the stator, in that the rotor is brought in a defined manner, with the motor at a standstill, into a second stop position in relation to the stator, lying opposite the first stop position, and in that the relative axial position between the rotor and the stator is respectively measured in the two stop positions.

Abstract: In order to improve a method to determine the lubricant filling degree of a fluid bearing in which the bearing gap of the fluid bearing is illuminated and the luminous reflectance is analyzed so that the filling degree can be determined in a simple and reproducible manner, it is provided that a spatial intensity profile of the reflected light is recorded.

Abstract: A device for measuring torque on an electric motor, which has a first motor portion and a second motor portion, which are rotatable in relation to each other, is proposed, the device comprising a rotatable holding plate for receiving the first motor portion, by means of which plate a rotational movement of the first motor portion in relation to the second motor portion can be driven, and a holding device for the second motor portion for holding the second motor portion in a rotationally fixed manner, the holding plate being disposed and formed in such a way that, when external forces are exerted on the electric motor via the holding device, the electric motor can position itself in relation to the holding device in such a way that external forces influencing the torque measurement are minimized.

Abstract: A torque measuring device for electric motors comprising a stator and a rotor is disclosed in which a holding apparatus to hold the stator of a test electric motor is provided, a drive apparatus for the rotor is provided and a torque sensor that is coupled to the drive apparatus is provided.

Abstract: The invention relates to a dosing system to dispense a predetermined quantity of a fluid medium which comprises a digital signal processor control having an interface to emit a start signal and a stop signal and an interface to measure a sensor signal. A dispenser is provided that is triggered by the start signal and the stop signal and, in the interval between the two signals, dispenses a specific quantity of fluid, as well as a sensor unit which, triggered by the start signal, continuously measures the flow rate of the fluid fed to the dispenser and emits a sensor signal as a function of this flow rate. The digital signal processor control measures the sensor signal, determines the quantity of fluid dispensed by the dispenser from this signal and sends a stop signal to the dispenser when the quantity of fluid dispensed by the dispenser corresponds to the predetermined quantity of fluid.

Abstract: The invention relates to a hydrodynamic bearing arrangement for an electric motor, particularly for a spindle motor to drive the platters of a hard disk drive. The bearing arrangement comprises a shaft, a bearing bush and a thrust plate disposed fixedly on the shaft, the shaft and the thrust plate rotating with respect to the bearing bush, grooved patterns to generate fluid-dynamic pressure being provided on the thrust plate and/or the surfaces located opposite the thrust plate of the bearing sleeve and/or the cover plate. The grooved pattern comprises a number g of grooves distributed over the surface of the bearing sleeve, the thrust plate or the cover plate, wherein in the shaft and/or in the thrust plate, a number h of holes and/or recesses are provided at the inner edge of the thrust plate and/or at the outer edge of the shaft. According to the invention, the number g of grooves cannot be integrally divided by the number h of holes and likewise that h cannot be integrally divided by g.

Abstract: A measuring method to determine the noise emission of an electric motor is proposed in which the vibrational excitation of the running electric motor is measured by a laser vibrometer device and this measured vibrational excitation is correlated with a noise level.

Abstract: A method to determine the natural frequencies of a bearing system having a shaft arranged on bearings is disclosed in which the shaft is vibrationally excited from one end of the shaft and a measurement signal is picked up at the other end of the shaft using a vibration sensor.

Abstract: In order to improve a method to determine the lubricant filling degree of a fluid bearing in which the bearing gap of the fluid bearing is illuminated and the luminous reflectance is analyzed so that the filling degree can be determined in a simple and reproducible manner, it is provided that a spatial intensity profile of the reflected light is recorded.

Abstract: A torque measuring device for electric motors having a rotor and a stator is proposed, said apparatus comprising a holding apparatus to hold the stator non-rotatably, an eddy current brake device which can be used to brake the rotor and a torque sensor connected to the eddy current brake device.

Abstract: A torque measuring device for electric motors comprising a stator and a rotor is disclosed in which a holding apparatus to hold the stator of a test electric motor is provided, a drive apparatus for the rotor is provided and a torque sensor that is coupled to the drive apparatus is provided.

Abstract: A method for filling the bearing gap of a hydrodynamic bearing with a lubricant, where drops of lubricant are produced in a defined manner and are applied to a defined region of the bearing to be filled.

Abstract: In order to provide a measuring device for electric motors, in particular spindle motors, comprising a motor mount, in which the electric motor to be tested can be positioned on the stator side for the measurement, and a first runout measuring device, which has at least a first runout sensor and with which a runout in a first direction can be sensed on a rotor of the electric motor held in the motor mount, which device allows the most efficient possible measuring of individual parameters of an electric motor, it is proposed to provide a second runout measuring device which has at least a second runout sensor and with which a runout of the rotor in a second direction, extending transversely in relation to the first direction, can be measured at the same time as the runout in the first direction.

Abstract: A device for measuring torque on an electric motor, which has a first motor portion and a second motor portion, which are rotatable in relation to each other, is proposed, the device comprising a rotatable holding plate for receiving the first motor portion, by means of which plate a rotational movement of the first motor portion in relation to the second motor portion can be driven, and a holding device for the second motor portion for holding the second motor portion in a rotationally fixed manner, the holding plate being disposed and formed in such a way that, when external forces are exerted on the electric motor via the holding device, the electric motor can position itself in relation to the holding device in such a way that external forces influencing the torque measurement are minimized.