Device having a drive unit, and method

Abstract

The invention relates to a device (1) having a drive unit (3) for driving a movable drive part (4) and having a switchable friction brake (2), wherein the drive part (4) can be braked and / or held stationary, wherein the device comprises sensor means and a control apparatus, wherein the control apparatus processes a detectable measured sensor value of a measurement parameter, and wherein, when the friction brake (2) is in braking effect, and starting from the static state of the drive part (4), a drive level of the drive unit is increased against the effect of the friction brake (2) which is in braking effect until the drive part (4) passes from the static state into a temporally subsequent slipping state, in which a braking torque caused by the friction brake is maintained on the driven movement of the drive part (4). According to the invention, the control apparatus and the sensor means are designed such that, over a predetermined measurement interval which lies within a range in which the drive part is in the slipping state, a plurality of measured sensor values ​​can each be detected at different times for a predetermined measurement parameter, wherein the measurement parameter correlates with a braking torque during the slipping state in order to determine a braking effect of the friction brake (2) on the drive part (4) in an actual state of the friction brake (2) on the basis of the plurality of measured sensor values ​​of the same measurement parameter.

Description

[0001] "Device with a drive unit and method"

[0002] State of the art

[0003] In devices such as machines, for example, machine tools, a drive unit is used to drive a movable drive part of the device or machine. For example, the movable drive part can be linearly or rotationally driven, for example, continuously driven. Drive motors, for example, are frequently used as the drive.

[0004] To ensure safe operation of the device, different types and design principles of braking devices are used in practice to decelerate the moving drive part or the units driven by it. For example, switchable friction brakes are used to decelerate the driven, moving drive part through friction between friction partners that are at least partially part of the friction brake. The friction brake can be designed to hold the drive part stationary in a static state.

[0005] In order to avoid a malfunction or failure of the friction brake or to minimize the potential danger to persons in the immediate vicinity of the device, high and defined safety requirements are placed on the operator of the device or machine or machine tool.

[0006] Object and advantages of the invention

[0007] The object of the present invention is to improve a device described above with regard to safe operation. In particular, compliance with specifications or defined standards regarding the functional testing of brakes such as friction brakes is to be improved.

[0008] This problem is solved by the independent claims. The dependent claims reveal advantageous and expedient developments.

[0009] The invention is based on a device with a drive unit for driving a movable drive part of the device and with a switchable friction brake, wherein the moving drive part can be braked by the friction brake through friction between friction partners and / or can be held stationary in a static state of the drive part, wherein the device comprises sensor means and a control device for operating the device, wherein the control device processes a sensor measured value of a measurement parameter that can be detected by the sensor means, and wherein when the friction brake is in braking action and starting from the static state of the drive part, an increase in a drive dimension of the drive unit takes place against the effect of the friction brake in braking action,until, due to the effective drive dimension, the drive part moves from the static state into a slipping state of the moving drive part which is temporally subordinate to the static state, whereby in the slipping state of the drive part a braking torque caused by the friction brake is maintained on the driven movement of the drive part.

[0010] The essence of the invention is that the control device and the sensor means are designed such that a plurality of sensor measured values ​​can be recorded, each offset in time, for a predetermined measuring parameter over a predetermined measuring interval which lies within a range in which the drive part is in the slipping state, wherein the measuring parameter correlates with a braking torque of the friction brake acting on the driven drive part during the slipping state in the measuring interval in order to determine a braking effect of the friction brake on the drive part in an actual state of the friction brake on the basis of the plurality of sensor measured values ​​of the same measuring parameter.

[0011] For example, the current braking function or the actual condition of the friction brake can be effectively and safely assessed with regard to braking effect. For example, a reliable brake test is guaranteed by the Technical Committee "Machine Tools" and the Technical Committee "Machine Tools Safety" in compliance with EN ISO 16092-2:2020.

[0012] For example, the friction brake is subjected to a dynamic braking torque measurement. For example, the brake test is performed by comparing a cyclically measured actual value with a previously measured actual value. For example, the previously measured actual value correlates with the new state of the friction brake. For example, the previously measured actual value is used as the target value.

[0013] For example, the friction brake is deliberately caused to slip for a brake test. This involves increasing the drive power of the drive unit to the driven drive part from the stationary state of the drive part, upon which the applied or actuated friction brake acts. After overcoming a static holding torque, which acts on the drive part when the friction brake is actuated, a measurement is taken to record a dynamic braking torque. For example, the friction brake remains actuated during this time.

[0014] For example, parameters that can be specified during the measurement, such as operating parameters of the device, e.g., parameters of the drive unit, such as motor parameters of an electric drive forming the drive unit, are used to measure the actual state of the friction brake. For example, the motor parameters "actual current" in amperes (A) and / or the torque constant Kt in newton meters per ampere (Nm / A) are recorded or measured and further processed. For example, the motor torque correlates with the braking torque of the friction brake.

[0015] For example, the friction brake comprises a spring arrangement, for example a mechanical spring arrangement with a mechanical spring. For example, the friction brake comprises a spring arrangement for providing a braking effect and / or for providing .

[0016] For example, the friction brake is spring-assisted, or the friction brake is spring-actuated. For example, the switchable friction brake can be actuated or activated by a mechanical spring. For example, the effect of the friction brake can be switched on and off by the mechanical spring.

[0017] For example, the friction brake comprises two adjacent, e.g., opposing friction partners that are movable relative to one another. For example, one friction partner is assigned to the friction brake, and another friction partner is assigned to an element to be driven, e.g., the drive part.

[0018] For example, a measurement interval lies within a time range in which the drive component is in the slipping state. For example, all measurements for recording the sensor values ​​lie within the slipping state. For example, the end of the slipping state can be detected and / or mathematically determined when a measured limit value, e.g., a measured limit value of the braking torque, is reached.

[0019] For example, the measuring interval is defined by a measuring path that the drive part travels in the slipping state. For example, the measuring path refers to a path, such as a movement distance, that the drive part travels in the slipping state. For example, with regard to the drive part, the measuring path can be tapped as a path traveled during the measuring time by a part of the device that is motion-coupled to the drive part.

[0020] For example, the measuring travel is the travel of the moving drive part in the slipping state, e.g., a linear travel traveled by the linearly moving drive part or a part coupled to it. For example, the measuring travel is in the millimeter range or in the range of a fraction of a millimeter.

[0021] For example, the friction brake of the device refers to any one of all possible types of friction brakes.

[0022] For example, the friction brake of the device is a spring-actuated brake or a spring-actuated friction brake. Such a friction brake is described, for example, in the standard EN ISO 16092-2:2020. This standard is directed, for example, at safety brakes.

[0023] For example, the friction brake goes into an unactuated or non-braking state when energy is applied, e.g., by applying a magnetic force or electrical energy. For example, when the brake is switched off or the power fails, as is the case with a safety brake, the friction brake returns to a spring-actuated state. For example, the friction brake is a rest brake that exerts a braking effect without the application of energy, solely through spring force.

[0024] For example, the friction brake is an energy-operated brake that goes into the actuated state or into the braking state by supplying energy, e.g. by supplying a magnetic force or electrical energy.

[0025] For example, the friction brake returns to the deactivated state when the power is switched off or when there is a power failure. For example, such a friction brake, such as a working brake, only brakes when energy is supplied, e.g., only when electrical energy is supplied, or only when a magnetic force is acting, e.g., an electromagnetic force from an electromagnet.

[0026] For example, if the drive part is rotatably movable, e.g., rotates while driven or performs a rotary movement, the measuring path is a path along a circular path or a rotational path in the slipping state, for example, determinable by an angular degree value. For example, the measuring path is a path of a rotary movement of the drive part or of a part of the device that is motion-coupled to the drive part or of another component outside the device that is motion-coupled to the drive part and rotates or moves linearly or along a motion curve.

[0027] For example, the measuring path is a fraction of a complete rotation of 360 degrees, for example, in the range of a few degrees. For example, the measuring path lies between zero and 360 degrees within exactly one rotation of the drive part. For example, the acquisition of multiple sensor measured values ​​takes place within a rotation of the drive part of 360 degrees, or within exactly one complete rotation of the drive part.

[0028] For example, the measuring interval is defined by a measuring time that lies within a period of time in which the drive part is in the slipping state. For example, the measuring time is in the range of seconds, for example in the range of one second or in the range of two seconds. For example, the measuring time is in the range of a fraction of a second, for example in the range of tenths of a millimeter or in the range of a few hundredths of a second, or for example, the measuring time is in the range of milliseconds. For example, the measuring time is in the range of seconds, for example in the range of one second or in the range of up to two seconds. For example, a start measuring time of the measuring interval and / or an end measuring time of the measuring interval can be defined.For example, several initial measurement times and corresponding end measurement times can be specified for a measured value, for example for several or for all of the several recorded measured values.

[0029] For example, the control device and the sensor means are designed to determine a starting point in time for the slipping state of the drive part, wherein the braking effect of the friction brake is determined only after the starting point in time for the slipping state of the drive part and after the expiration of a first temporal phase of the slipping state of the drive part following the starting point in time. For example, the slipping state is divided into several temporal phases, comprising at least a first temporal phase and a final temporal phase.

[0030] For example, the starting time of the first measurement interval occurs after the end of the first temporal phase of the slipping condition or after a start-up phase. During the start-up phase, for example, a non-representative, abruptly changing, or discontinuous friction behavior of the friction partners is expressed.

[0031] For example, the effect of initial slipping behavior of the drive component from a stationary state, e.g. startup behavior of the drive component in the startup phase, on the recording of the sensor measurements is excluded. The startup phase regularly has a falsifying effect on a measurement result or is generally not representative for the assessment of the braking effect of the friction brake. As a rule, slipping behavior of the drive component from a stationary state in an initial temporal phase of the slipping state is not meaningful for assessing the actual state of the braking effect of the friction brake. For example, falsification of the assessment of the braking effect of the friction brake is avoided.

[0032] After the end of the starting behavior or after the end of the first phase of the slipping state, the friction brake or the drive part behaves evenly and not abruptly or discontinuously.

[0033] For example, in a temporal phase of the slipping state of the drive part following the first temporal phase of the slipping state, for example in several of the subsequent temporal phases of the slipping state, sensor measured values ​​are recorded, such as e.g. the determination of the gradient of the braking torque or a parameter that correlates with the braking torque.

[0034] For example, recorded sensor measurements for the respective different temporal phases of the slipping state of the drive component are only taken into account for the measurement at a time offset from the start of the slipping state. The time offset from the start of the slipping state to the beginning of the measurement of a first sensor measurement value, or the length of the first temporal phase of the slipping state or the start-up phase, is, for example, a few milliseconds, a few hundredths of a second, or a few tenths of a second.

[0035] For example, the change in the braking torque of the friction brake or a correlated parameter is evaluated over time.

[0036] For example, to determine the end of the start-up phase or the first phase of the slipping condition for recording a sensor measurement, a limit value analysis is carried out. For example, from the onset of the slipping condition, an increase in the curve of the braking torque or a correlated parameter is recorded, approaching zero. Once the zero increase or the increase in the curve of the braking torque is determined, the recording of sensor measurement values ​​or a first sensor measurement value begins, followed by the recording of further sensor measurement values.

[0037] For example, the sensor measurements are recorded as soon as the gradient of the braking torque curve falls below a predefined threshold or when the braking torque curve reaches a zero gradient. This is when the measurement interval for recording the sensor measurements begins.

[0038] For example, by not taking into account or by hiding or excluding a starting behavior of the friction brake, a falsification of the measurements and thus a falsification of the evaluation of the braking effect of the friction brake is avoided or minimized.

[0039] For example, by masking out the starting behavior of the friction brake, a starting peak of the slipping state, e.g. with a briefly higher detectable braking torque, is not taken into account and therefore does not have a distorting effect on the measurement.

[0040] For example, the slipping state is divided into several temporal phases, e.g., into a plurality of three or more than three temporal phases, for example, 4 to 20 or more than 20 temporal phases. For example, all temporal phases of the slipping state have the same duration, or the multiple temporal phases all have different durations, or the multiple temporal phases have two or more phases with the same duration and two or more phases with the same duration.

[0041] For example, the slippage condition of the

[0042] Drive part a free, practically almost frictionless movement of the friction partners between the friction surfaces of the friction partners and thus of the drive part, which moves freely driven.

[0043] For example, the control device and the sensor means are designed in such a way that the number of the multiple sensor measured values ​​offset in time can be specified.

[0044] For example, the number of time-shifted multiple sensor measured values ​​is two or more than two time-shifted sensor measured values ​​are recorded in the measuring interval.

[0045] For example, the number of sensor readings in a corresponding measuring interval is > 2, > 10, > 20, > 30, > 40, > 50, > 60, > 70, > 80, > 90 or > 100 sensor readings.

[0046] For example, exactly 100 sensor readings, or exactly 120 readings, or <500 sensor readings are recorded in a measurement interval. For example, the multiple sensor readings are recorded at the same time interval, e.g., with a time interval between the sensor readings of 20 milliseconds or 20 mS, of 40 mS, or of more than 40 mS.

[0047] For example, that the measuring interval lies within a range within which the rotating drive part completes one revolution.

[0048] For example, the measuring interval corresponds to a rotation time of the drive part, within which the drive part completes one or exactly one rotation or by exactly 360 angular degrees. For example, the measuring interval corresponds to a rotation time of the drive part, within which the drive part covers a distance that is shorter than the distance that the drive part covers when the drive part completes one rotation of 360 angular degrees around its axis of rotation, or shorter than, for example, 300 angular degrees or shorter than, for example, 200 angular degrees or shorter than, for example, 180 angular degrees. For example, the control device and the sensor means are designed in such a way that by actuating the friction brake the friction brake is in a predefinable conditioning state before the measuring interval. For example, actuating the friction brake comprises switching or turning on and then releasing the friction brake. After releasing or turningthe drive part does not experience any friction brake resistance and could, for example, move under power. This achieves this simply and reproducibly: the surfaces of the friction partners are pressed against one another, causing particles to detach from the surfaces due to pressure, and the friction surfaces then become free again in a contactless state, whereby the released particles or the fluids heated by friction can detach from the friction surfaces, for example, detach, fall off or evaporate. Surface components are thus removed after the friction brake is released.

[0049] For example, the friction brake is applied before the onset of slipping, for which the friction brake is already in the applied but no longer released state. For example, the application of the friction brake brings the friction surfaces of the friction brake into a chemically and physically conditioned state.

[0050] For example, the friction brake may be actuated exactly once or multiple times before the measuring interval. For example, the time at which the friction brake is actuated relative to the start of the measuring interval can be specified via the control unit. For example, the time at which the friction brake is actuated relative to the start of the measuring interval is a few seconds, for example, one second before the start of the measuring interval or one second before the start of the slipping state.

[0051] For example, this ensures that the friction brake is in a comparable state for all measurements taken before the actual measurement begins, namely the conditioning state of the friction brake. For example, the conditioning state of the friction brake always ensures that the initial state immediately before the measurement begins is the same or comparable. The same, or at least essentially the same, conditioning state can be achieved for all different states before the sensor measurement values ​​begin to be recorded, regardless of the respective state of the friction brake before the conditioning state or before actuation. For example, this makes the findings gained from the sensor measurement values ​​easier to compare with one another and more meaningfully.

[0052] For example, the conditioning state is achieved in various possible ways, for example by actuating the friction brake, e.g. via a braking time or braking duration that can be specified or predetermined via the control device, or a predetermined angle of rotation that can be specified or predetermined, e.g. via a predetermined number of brake changes "on" / "off" or of actuation or switching operations of the friction brake.

[0053] In this way, parameters of the friction brake that affect the measurement, such as moisture on the friction surfaces, water, oil, grease, etc., dirt, dust, particles on the friction surfaces, surface temperature of the friction surfaces, are conditioned or balanced in such a way that a comparable condition of the friction brake is achieved before the start of each measurement.

[0054] For example, the drive unit comprises an electric motor, with a motor current of the electric motor serving as a measurement parameter. For example, the electric motor serves to drive the drive part, so that the electric motor works against the effect of the friction brake when the slipping state is reached, and thus the motor current drawn correlates with the braking force provided by the friction brake. For example, it is reliably and easily possible to map a current or effective braking torque of the friction brake using the regularly and easily measurable motor current that the electric motor draws when the friction brake is applied.

[0055] For example, the torque or counter-braking torque derived from the absorbed motor current serves as the basis for assessing the current braking effect or the currently available maximum braking torque of the friction brake. For example, it is possible to indirectly calculate the current braking torque of the friction brake provided by the friction brake from the measured motor current absorbed by the electric motor.

[0056] For example, a processing instruction for processing the multiple sensor measured values ​​is stored in the control device in order to determine the braking effect of the friction brake in the actual state of the friction brake. For example, the processing instruction includes an algorithm and / or, for example, computer software.

[0057] For example, the processing rule includes a mathematical and / or a statistical processing rule.

[0058] For example, the processing instructions subject sensor measurement values ​​recorded by the sensor devices to mathematical processing or evaluation.

[0059] For example, the processing instruction is used to create a calculated value of the measurement parameter, for example by averaging based on several individual sensor measurement values.

[0060] For example, the processing specification includes various mathematical methods for processing the sensor measurements. For example, the processing specification is used to calculate an arithmetic, geometric, and / or root-mean-square based on the determined sensor measurements.

[0061] For example, the processing instruction includes a programmable filter, e.g. for averaging, such as torque average, related to a braking torque of the friction brake or to a counter-torque to the braking torque of the friction brake.

[0062] For example, the processing rule includes a weighted averaging method. For example, the processing rule uses the polynomial method or another mathematical method to generate a representative value from several different individual values, such as the sensor measurements.

[0063] For example, according to the processing specification, so-called time triggering is performed. For example, according to the processing specification, mathematical functions are used for gradient detection, based on the temporal progression of the braking torque when the friction brake is slipping. For example, the processing specification includes a mathematical derivation of the measured value function or simple gradient detection, whereby the function is formed based on the recorded sensor measured values.

[0064] The invention also relates to a method for determining a braking effect of a friction brake of a device according to one of the embodiments described above.

[0065] For example, all types of friction brakes can be tested using the method with regard to determining the braking effect of the friction brake.

[0066] For example, the device comprises a drive unit for

[0067] Drive of a movable drive part of the device and the switchable friction brake, wherein the moving drive part can be braked with the friction brake by friction between friction partners and / or can be held stationary in a static state of the drive part, wherein the device comprises sensor means and a control device for operating the device, wherein the control device processes a sensor measured value of a measurement parameter that can be detected by the sensor means, and wherein, when the friction brake is in braking action and starting from the static state of the drive part, an increase in a drive dimension of the drive unit takes place against the effect of the friction brake in braking action, until, due to the effective drive dimension, the drive part moves from the static state into a slipping state of the moving drive part that is temporally subsequent to the static state,whereby in the slipping state of the drive part a braking torque of the friction brake is maintained on the driven movement of the drive part.,

[0068] Over a predetermined measuring interval, which lies within a range in which the drive part is in the slipping state, several sensor measured values ​​are recorded for a predetermined measuring parameter, each with a time offset, wherein the measuring parameter correlates with a braking torque of the friction brake acting on the driven drive part during the slipping state in the measuring interval, and wherein a braking effect of the friction brake in an actual state of the friction brake on the drive part is determined on the basis of the several sensor measured values ​​of the same measuring parameter.

[0069] For example, it is advantageously possible to characterize the actual state of the friction brake.

[0070] For example, the current actual state of the friction brake is determined during slipping and reflects a holding effect of the friction brake in the static state of the drive part or allows conclusions to be drawn about the static holding effect of the friction brake.

[0071] For example, the braking effect of the friction brake is determined on the basis of sensor measurement values ​​that represent or determine the braking torque of the friction brake.

[0072] For example, the braking effect of the friction brake is determined on the basis of sensor measurement values ​​that determine a drive dimension of the drive unit during the slipping state of the drive part.

[0073] For example, a drive dimension of the drive unit during the slipping state of the drive part is characterized by the acceleration of the drive part and / or the speed of the drive part and / or the absolute path or the absolute angle of rotation of the drive part.

[0074] For example, sensor measurements are recorded to determine the actual state of the friction brake when, in relation to the drive part of the drive unit, the acceleration of the drive part is less than 500 mm / s, for example. 2 or e.g. less than 300 mm / s 2 or less than 100 mm / s 2 or less than 50 mm / s 2 10 mm / s 2 or e.g. less than 5 mm / s 2 or less than 3 mm / s 2 or less than 2 mm / s 2 is .

[0075] For example, the sensor measured value is the motor current of an electric motor in the drive unit. The higher the current consumption of the electric motor in the drive unit, the greater the current braking torque of the friction brake. This allows, for example, the motor current to be used to directly determine the braking torque of the friction brake.

[0076] For example, a torque value of the drive unit is calculated based on the sensor measurements. For example, the torque value of the drive unit at the time of the torque measurement correlates with the braking torque of the friction brake at the time of measurement.

[0077] For example, an average torque value for the drive unit is calculated based on the sensor measurements. For example, several sensor measurements are recorded, and an average of the sensor measurements is calculated from them. For example, the average of the sensor measurements correlates with an average torque value, which allows conclusions to be drawn about the braking torque of the friction brake to determine the actual state of the friction brake.

[0078] For example, at intervals during an operating period of the friction brake, the actual state of the friction brake is determined in relation to its braking effect on the drive part and a history of the various determined actual states is used as a basis for evaluating the friction brake with regard to a forecast of a future function of the friction brake.

[0079] For example, the actual state of the friction brake is compared over a period of operation of the device or over the course of the device's operation, e.g. at regular intervals, e.g. once an hour, once a day, once a week, with a reference state of the friction brake, e.g. when the friction brake is in a new condition. For example, on this basis, a regular test of the friction brake is carried out during the useful life of the device or the friction brake. The course of the regularly recorded actual state values ​​can allow a forecast, for example when a braking torque of the friction brake is expected to fall below a target value. This enables improved planning with regard to the functional reliability of the friction brake and thus the operation of the device. For example, repair, maintenance and / or downtimes for a device such as a machine tool can be better estimated.For example, a history of the various determined actual states is used to determine a point in time, at which point in time a limit value of the braking effect of the friction brake is expected.

[0080] For example, various actual states of the friction brake derived from the sensor measurements (e.g., one actual state is determined daily) are subjected to a trend analysis. This makes it possible, for example, to determine after one week, or after two weeks, or more than two weeks, an expected state of the actual state of the friction brake at which a limit value for the actual state of the friction brake is likely to be reached. This procedure is used, for example, for the early detection of wear or for the detection of wear dynamics and, if necessary, for determining an expected failure point of the friction brake.

[0081] For example, based on trend analysis, better planning of the use of the device such as a machine tool can be achieved.

[0082] Character description

[0083] Further features and advantages of the invention are explained in more detail with reference to the figures.

[0084] In detail:

[0085] Fig. 1 shows a measurement diagram for recording a braking behavior of a friction brake according to a method for determining a braking effect of the friction brake and

[0086] Fig. 2 shows a device with a drive unit for driving a drive part and with a friction brake. The measurement diagram according to Fig. 1 illustrates a brake test of a friction brake carried out to assess the actual condition of the friction brake. The actual brake test of the friction brake is preceded, for example, by a process which, for example, lies within a first phase described below.

[0087] The measurement diagram shown in Fig. 1 is structured as an xy diagram and has an x-axis representing a time axis and a y-axis on which the torque of the respective friction brake is plotted. For example, torque and time are assigned SI units. For example, the x-axis is assigned the unit of seconds ("s"), and the y-axis is assigned the unit of newton meters ("Nm").

[0088] The respective torque of the friction brake refers to a braking torque caused by the friction brake in an active or braking state of the friction brake, which corresponds to a closed state of the friction brake.

[0089] The measurement diagram shown in Fig. 1 shows the measured values ​​Ml to M30 determined before and during a brake test with the friction brake to be tested.

[0090] For example, on the basis of a polynomial method, the concrete or absolute measured values ​​Ml to M30 are filtered and, for example, displayed in the measurement diagram according to a curve K calculated in this way.

[0091] The measured values ​​Ml to M30 and the measurement curve K are shown schematically in Fig . 1 .

[0092] The braking test is divided into several time phases, here as an example into three time phases.

[0093] A first phase lies between the times xO at time "zero" or a start time xO and a later time xl. At the start time xO, the friction brake is closed. For example, at the start time xO, the drive unit is not actively driving or...

[0094] The first phase xO to xl covers a static range of the friction brake, which represents a state of the closed friction brake with statically relative friction partners and force-induced pressed together.

[0095] In the first phase, with the friction partners of the friction brake stationary and pressed against each other, the measured values ​​Ml to M6 are recorded successively at successive, spaced-apart points in time between XO and XI with xl > xO. For example, there are 5 measuring points in time for the respective measured values ​​Ml to M5 between the points in time xO and xl.

[0096] In the first phase, the drive power of the drive unit is gradually increased. In this phase, the six measured values ​​Ml to M6, for example, are recorded using sensors. The measured values ​​Ml to M6 represent an increasing braking torque of the friction brake, with M6 > M5 > M4 > M3 > M2 > Ml.

[0097] A second phase, which is comparatively short to the first phase, exists between the time xl and the later time x2. The second phase is, for example, a transition phase. Within the second phase there is, for example, exactly one measured value M7. For example, two or more measured values ​​are also possible in the second phase. Within the second phase the gradient of the measured curve K is not "zero" or. Within the second phase the gradient of the measured curve K is not approximately "zero".

[0098] The second phase represents a phase of the friction brake in which the increasing drive power of the drive unit causes the friction brake to slip and one friction partner slips. In the process, the previously static friction partners leave their static state. In the second phase, one friction partner moves relative to the other friction partner at a comparatively low relative speed, e.g. with relatively low acceleration. In the second phase, the friction partners of the friction brake, which are pressed against one another, move from the static state into a slipping state and a drive part that can be driven by the drive unit moves accordingly. In the process, a static holding torque is overcome between the time xl and the time x2.

[0099] The first and second phases are not used to assess the braking effect of the friction brake or are not used for the brake test. The first and second phases are not relevant for the brake test.

[0100] The braking test in the time interval between x2 and x3 refers solely to a dynamic braking torque measurement.

[0101] The third phase follows the second phase and, for example, follows the second phase immediately or via a short intermediate phase (not shown) as shown in Fig. 1. The dynamic braking torque measurement takes place in the third phase between times X2 and X3.

[0102] A starting point of the measurement interval at time x2 is specified, for example, by determining the "zero" slope of the friction brake torque or the "zero" slope of the measurement curve K. This is the case, for example, with a tolerance starting at time x2.

[0103] For example, the slope "zero" is an approximate zero slope. For example, in the measurement interval, the slope determined from the measured values ​​over the measurement period lies within an upper limit, such as a maximum limit, and a lower limit, such as a minimum limit.

[0104] This is followed by the third phase, or the measuring interval between x2 and x3, up to time x3. The third phase, which concerns the actual friction brake measurement, represents a dynamic measuring range for the braking torque measurement. During the third phase, with the drive unit actively driving, a predefined number of measured values ​​are recorded; for example, one hundred measured values ​​are recorded. The measured values ​​M8 to M30 are shown schematically in Fig. 1.

[0105] The end of the measuring interval at time x3 is reached when a predeterminable number of measurements, for example 100 measurements of a braking torque of the friction brake, have been recorded.

[0106] For example, to evaluate the friction brake, which refers only to the third phase, the measurement curve K is considered.

[0107] A condition of the friction brake "not OK" is determined, for example, when the measuring curve K reaches or exceeds an upper or maximum limit value of a braking torque or torque Bmax within the third phase between x2 and x3.

[0108] A condition of the friction brake "not OK" is determined, for example, when the measuring curve K reaches or falls below a lower or minimum limit value of a braking torque or torque Bmin within the third phase between x2 and x3.

[0109] A condition of the friction brake "not OK" is determined, for example, when the measuring curve K within the third phase between x2 and x3 reaches or exceeds an upper or maximum limit value of a braking torque or torque Bmax and / or when the measuring curve K within the third phase between x2 and x3 reaches or falls below a lower or minimum limit value of a braking torque or torque Bmin.

[0110] For example, within the third phase, below the minimum limit value of the braking torque Bmin, there is a tolerable minimum limit braking torque Bmin tolerance, which can be used to evaluate the actual condition of the friction brake. For example, within the third phase, above the maximum limit value of the braking torque Bmax, there is a tolerable maximum limit braking torque Bmax tolerance, which can be used to evaluate the actual condition of the friction brake.

[0111] Fig. 2 shows a device 1 with a switchable friction brake 2, which is a mechanical brake, and with a drive unit 3 for driving a drive part 4. The drive part 4, such as a rotating spindle, is concealed in Fig. 2 by outer housing parts of the device 1. For example, the device 1 is used to drive a machine tool. For example, the drive unit 3 is an electric motor drive for the electric motor-driven rotating drive of the spindle.

[0112] Inside the device 1, friction partners of the friction brake (not visible in Fig. 2), sensor means and a control device for operating the device are accommodated.

[0113] For example, the drive effect is transmitted from the drive unit 3 to the drive part 4 via a gear.

[0114] Reference symbol list

[0115] 1 Device 2 Friction brake

[0116] 3 Drive unit

[0117] 4 drive part

Claims

Claims 1. Device with a drive unit for driving a movable drive part of the device and with a switchable friction brake, wherein the moving drive part can be braked by the friction brake through friction between friction partners and / or can be held stationary in a static state of the drive part, wherein the device comprises sensor means and a control device for controlling the operation of the device, wherein the control device processes a sensor measured value of a measurement parameter that can be detected by the sensor means, and wherein, when the friction brake is in braking action and starting from the static state of the drive part, an increase in the drive dimension of the drive unit takes place against the effect of the friction brake in braking action,until, due to the effective drive dimension, the drive part moves from the static state into a slipping state of the moving drive part which is temporally subordinate to the static state, wherein in the slipping state of the drive part, a braking torque caused by the friction brake is maintained on the driven movement of the drive part, characterized in that the control device and the sensor means are designed such that, over a predetermined measuring interval which lies within a range in which the drive part is in the slipping state, several sensor measured values ​​can be recorded with a time offset for a predetermined measuring parameter, wherein the measuring parameter correlates with a braking torque of the friction brake acting on the driven drive part during the slipping state in the measuring interval,in order to determine a braking effect of the friction brake on the drive part in an actual state of the friction brake on the basis of the several sensor measured values ​​of the same measuring parameter.

2. Device according to claim 1, characterized in that the measuring interval is defined by a measuring path which the drive part travels in the slipping state.

3. Device according to claim 1 or claim 2, characterized in that the measuring interval is defined by a measuring time which lies within a period in which the drive part is in the slipping state. 4 . Device according to one of the preceding claims, characterized in that the control device and the sensor means are designed to determine a starting point in time of the slipping state of the drive part, wherein the determination of the braking effect of the friction brake only takes place after the Start time of the slipping state of the drive part and after expiry of a first temporal phase of the slipping state of the drive part following the start time.

5. Device according to one of the preceding claims, characterized in that the control device and the sensor means are designed in such a way that the number of the multiple sensor measured values ​​offset in time can be predetermined.

6. Device according to one of the preceding claims, characterized in that the measuring interval lies within a range within which the rotating drive part completes one revolution.

7. Device according to one of the preceding claims, characterized in that the control device and the sensor means are designed in such a way that the friction brake assumes a predeterminable conditioning state by actuation before the measuring interval. 8 . Device according to one of the preceding claims, characterized in that the drive unit comprises an electric motor, wherein a motor current of the electric motor serves as a measuring parameter.

9. Device according to one of the preceding claims, characterized in that a processing instruction for processing the plurality of sensor measured values ​​is stored in the control device in order to determine the braking effect of the friction brake in an actual state of the friction brake.

10. Method for determining a braking effect of a friction brake of a device according to one of the preceding claims, wherein the device comprises a drive unit for driving a movable drive part of the device and a switchable friction brake, wherein the moving drive part can be braked by the friction brake through friction between friction partners and / or can be held stationary in a static state of the drive part, wherein the device comprises sensor means and a control device for controlling the operation of the device, wherein the control device processes a sensor measured value of a measurement parameter that can be detected by the sensor means, and wherein when the friction brake is in braking effect and starting from the static state of the drive part, an increase in a drive dimension of the drive unit takes place against the effect of the friction brake in braking effect,until, due to the effective drive dimension, the drive part moves from the static state into a slipping state of the moving drive part which is temporally subordinate to the static state, wherein in the slipping state of the drive part, a braking torque of the friction brake on the driven movement of the drive part is maintained, characterized in that over a predetermined measuring interval which lies within a range in which the drive part is in the slipping state, several sensor measured values ​​are recorded with a time offset for a predetermined measuring parameter, wherein the measuring parameter correlates with a braking torque of the friction brake acting on the driven drive part during the slipping state in the measuring interval, and that on the basis of the several sensor measured values ​​of the same measuring parameter, a braking effect of the friction brake in an actual state of the friction brake on the drive part is determined.

11. Method according to claim 10, characterized in that a motor current of an electric motor of the drive unit is determined as the sensor measured value.

12. Method according to one of claims 10 to 11, characterized in that a torque value of the drive unit is calculated on the basis of the sensor measured values.

13. Method according to one of claims 10 to 12, characterized in that an average torque value of the drive unit is calculated on the basis of the sensor measured values.

14. Method according to one of claims 10 to 13, characterized in that at time intervals during an operating period of the friction brake, the actual state of the friction brake is determined in relation to its braking effect on the drive part and a course of the various actual states determined is used as a basis for evaluating the friction brake with regard to a forecast of a future function of the friction brake.

15. Method according to claim 14, characterized in that a course of the various determined actual states is used to determine a point in time, at which point in time a limit value of the braking effect of the friction brake is expected.

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