WO2024256427A1 - Device having a drive unit, and method - Google Patents

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

"Device with a drive unit and method"

State of the art

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 driven linearly or in a rotating manner, for example continuously driven. Drive motors, for example, are regularly used as a drive.

In practice, different types and construction principles of braking devices are used to brake the moving drive part or the units driven by it in order to ensure safe operation of the device. For example, switchable friction brakes are used to brake the driven, moving drive part by means of 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.

In order to avoid a malfunction or failure of the friction brake or to minimize the risk potential for 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.

Task and advantages of the invention

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

This problem is solved by the independent claims. The dependent claims show advantageous and expedient further developments.

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 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 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 that is temporally subsequent 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.

The essence of the invention is 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 for a predetermined measuring parameter, each with a time offset, wherein the measuring parameter is compared with a braking torque of the friction brake acting on the driven drive part during the measuring interval. Slipping condition is correlated 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.

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

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

For example, the friction brake is deliberately made to slip for a brake test. For example, the drive power of the drive unit on the driven drive part is increased from the stationary state of the drive part on which the closed or activated friction brake acts. After overcoming a static holding torque that acts on the drive part when the friction brake is activated, the measurement is taken to record a dynamic braking torque. For example, the friction brake remains activated during this time.

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 for the measurement with regard to 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) is recorded or measured and further processed. For example, the motor torque correlates with the braking torque of the friction brake.

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 .

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

For example, the friction brake comprises two adjacent, e.g. opposite, 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, for example the drive part.

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

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 measured as a path covered in the measuring time by a part of the device which is motion-coupled to the drive part.

For example, the measuring path is a path of the moving drive part in the slipping state, e.g. a linear path that the linearly moving drive part or a part coupled to it travels. For example, the measuring path is in the millimeter range or in the range of a fraction of a millimeter.

For example, the friction brake of the device refers to any type of all possible types of friction brakes.

For example, the friction brake of the device is a spring-operated brake or a spring-operated friction brake. For example, such a friction brake is described in the standard EN ISO 16092- 2:2020. This standard is aimed, for example, at safety brakes.

For example, the friction brake goes into an unactuated or non-braking state when energy is supplied, e.g. by supplying a magnetic force or electrical energy. For example, the friction brake falls back into a spring-actuated state when it is switched off or when the energy fails, as is the case with a safety brake. For example, the friction brake is a rest brake, which develops a braking effect without the supply of energy, only through spring force.

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.

For example, if the power is switched off or if the power fails, the friction brake falls into the unactuated state. state. 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.

For example, if the drive part is movable in a rotating manner, e.g. rotates when driven or carries out 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 coupled in motion to the drive part or of another component outside the device that is coupled in motion to the drive part and rotates or moves linearly or along a motion curve.

For example, the measuring path is a fraction of a complete rotary movement of 360 degrees, for example in the range of a few degrees. For example, the measuring path is between zero and 360 degrees within exactly one revolution of the drive part. For example, the recording of the multiple sensor measured values takes place within a rotary movement of the drive part of 360 degrees or within exactly one complete revolution of the drive part.

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 second range, 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 tenth of a millimeter range or in the range of a few hundredths of a second, or for example, the measuring time is in the millisecond range. For example, the measuring time is in the second range, for example in the range of one second or in the range of up to two seconds. For example, a start measurement time of the measurement interval and/or an end measurement time of the measurement interval can be specified in a defined manner. For example, several start 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.

For example, the control device and the sensor means are designed to determine a start 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 the expiry of a first temporal phase of the slipping state of the drive part following the start time. For example, the slipping state is divided into several temporal phases, comprising at least a first temporal phase and a last temporal phase.

For example, the start time of the first measurement interval is after the end of the first temporal phase of the slipping state or after a start-up phase. In the start-up phase, for example, a non-representative, e.g. abruptly changing or discontinuous friction behavior of the friction partners is expressed.

For example, the effect of an initial slipping behavior of the drive part from the resting state, e.g. a start-up behavior of the drive part in the start-up phase, on the recording of the sensor measured values is excluded. The start-up phase regularly has a distorting effect on a measurement result or is regularly not representative for the evaluation of the braking effect of the friction brake. As a rule, a slipping behavior of the drive part from the resting state in an initial temporal phase of the slipping state is not meaningful for the assessment of the actual state of the braking effect. the friction brake. For example, a distortion of the assessment of the braking effect of the friction brake is avoided.

After the end of the start-up 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.

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 the determination of the gradient of the braking torque or a parameter that correlates with the braking torque.

For example, recorded sensor measurements for the respective different temporal phases of the slipping state of the drive part 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 start 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 or a few hundredths of a second or a few tenths of a second.

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

For example, to determine the end of the start-up phase or the first phase of the slipping state for the recording of a sensor measurement value, a limit value analysis is carried out. For example, from the beginning of the slipping state, a slope of the braking torque curve or a parameter correlated with it is recorded, approaching zero. With the When the zero gradient or the gradient of the braking torque curve is determined to be approaching zero, the recording of sensor measured values or a first sensor measured value begins, followed by the recording of further sensor measured values.

For example, the sensor measurement values are recorded as soon as the gradient of the braking torque curve falls below a predefined threshold value or when the gradient of the braking torque curve reaches "zero". The measuring interval for recording the sensor measurement values then begins.

For example, by not taking into account or by hiding or excluding the start-up behaviour 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 minimised.

For example, by masking out or excluding a start-up behavior of the friction brake, a start-up peak of the slipping state, e.g. with a briefly higher detectable braking torque, is not taken into account for the measurement and therefore does not have a distorting effect.

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

For example, the slippage state of the

drive part a free, between the friction surfaces of the friction partners practically almost frictionless movement of the Friction partner and thus of the drive part, which moves freely driven.

For example, the control device and the sensor means are designed in such a way that the number of temporally offset multiple sensor measurement values can be specified.

For example, the number of temporally offset multiple sensor readings is two or more than two temporally offset sensor readings are recorded in the measuring interval.

For example, the number of sensor measurements in a corresponding measurement interval is > 2, > 10, > 20, > 30, > 40, > 50, > 60, > 70, > 80, > 90 or > 100 sensor measurements.

For example, exactly 100 sensor measurements or exactly 120 measurements or < 500 sensor measurements are recorded in one measurement interval. For example, the multiple sensor measurements are recorded with the same time interval between each other, e.g. with a time interval between the sensor measurements of 20 milliseconds or 20 mS, of 40 mS or of more than 40 mS.

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

For example, the measuring interval corresponds to a rotation time of the drive part, within which the drive part completes one or exactly one revolution or 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 smaller 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 smaller than, for example, 300 angular degrees or smaller than, for example, 200 angular degrees or smaller than, for example, 180 angular degrees. For example, the control device and the sensor means are designed in such a way that when the friction brake is actuated before the measuring interval, the friction brake is in a predeterminable conditioning state. For example, actuating the friction brake involves switching or turning the friction brake on and then releasing it again. After it is released or turned on, the drive part experiences no friction brake resistance and could, for example, move under power. This makes it easy and reproducible that the surfaces of the friction partners are pressed together, causing particles to detach from the surfaces due to pressure, and then the friction surfaces are released again in a contactless state, allowing the released particles or liquids heated by the friction to detach from the friction surfaces, for example by detaching, falling off or evaporating. Surface components are therefore removed after the friction brake is released.

For example, the friction brake is activated before the start of the slipping state, for which the friction brake is in the activated but no longer released state anyway. For example, the activation of the friction brake brings the friction surfaces of the friction brake into a chemically and physically conditioned state.

For example, the friction brake may be activated exactly once or several times before the measuring interval. For example, the time at which the friction brake is activated 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 activated 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.

For example, this allows a comparable state of the friction brake for all measurements taken before the start of the actual measurement is achieved, namely the conditioning state of the friction brake. For example, the conditioning state of the friction brake always ensures an identical or comparable initial state immediately before the start of the measurement. The same or at least essentially identical conditioning state can be achieved regardless of the respective state of the friction brake before the conditioning state or before activation for all different states before the start of the recording of sensor measured values. For example, this makes the findings gained from the sensor measured values easier and more meaningful to compare with one another.

For example, the conditioning state is achieved in a variety of 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 predeterminable, e.g. predetermined, angle of rotation, or via a predetermined number of brake changes "on" / "off" or of actuation or switching operations of the friction brake.

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 state of the friction brake is achieved before the start of each measurement.

For example, the drive unit comprises an electric motor, wherein a motor current of the electric motor serves 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 driving to reach the slipping state and thus the motor current consumed correlates with the braking force provided by the friction brake. For example, it is possible to reliably and easily map a current or effective braking torque of the friction brake using the regularly easily measurable motor current that the electric motor absorbs when the friction brake is actuated.

For example, the torque or counter-braking torque derived from the motor current used serves as a basis for assessing the current braking effect or the maximum braking torque of the friction brake that can currently be provided. For example, it is possible to indirectly calculate the current braking torque of the friction brake provided by the friction brake from the recorded motor current that the electric motor uses.

For example, a processing instruction for processing the multiple sensor measurement 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. For example, the processing instruction includes an algorithm and/or, for example, computer software.

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

For example, with the processing instruction, sensor measurement values recorded by the sensor devices are subjected to mathematical processing or evaluation.

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.

For example, the processing specification includes different mathematical methods for processing the sensor measurements. For example, the processing rule is used to calculate an arithmetic, geometric and/or a root mean value based on the determined sensor measurements.

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.

For example, the processing rule includes a weighted averaging process. For example, the processing rule works according to the polynomial method or another mathematical method to form a representative value from several different individual values such as the sensor measurements.

For example, according to the processing specification, so-called time triggering is carried out. For example, according to the processing specification, mathematical functions are used to detect gradients, based on the time course 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 on the basis of the recorded sensor measured values.

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.

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

For example, the device comprises a drive unit for

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 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 that is subsequent 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.

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 at a different time, whereby the measuring parameter is correlated with a braking torque of the friction brake acting on the driven drive part during the slipping state in the measuring interval, and whereby 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.

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

For example, the current 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.

For example, the braking effect of the friction brake is determined on the basis of sensor measurements that represent or determine the braking torque of the friction brake.

For example, the braking effect of the friction brake is determined on the basis of a recording of sensor measurements which determine a drive dimension of the drive unit during the slipping state of the drive part.

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.

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 e.g. less than 500 mm/s 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 .

For example, a motor current of an electric motor in the drive unit is determined as a sensor measurement value. The greater the current consumption of the electric motor in the drive unit, the greater the current braking torque of the friction brake. This means that conclusions can be drawn directly about the braking torque of the friction brake based on the motor current, for example.

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 correlates to the Time of measurement of the torque value with the braking torque of the friction brake at the time of measurement.

For example, an average torque value of 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 in order to determine the actual state of the friction brake.

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

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 new. For example, on this basis, a regular test of the friction brake is carried out during the useful period of the device or the friction brake. The regularly recorded actual state values can, over their course, allow a forecast to be made, 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, with a device such as a machine tool, repair, maintenance and/or downtimes can be better estimated. For example, a history of the various determined actual states is used to determine a point in time at which a limit value of the braking effect of the friction brake is expected.

For example, various actual states of the friction brake derived from the sensor measurements, for example one actual state is determined daily, are subjected to a trend analysis. For example, after one week or after two or more weeks, an expected state of the actual state of the friction brake can be determined at which a limit value with regard to the actual state of the friction brake is expected 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 time of the friction brake.

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

character description

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

In detail:

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

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 braking test of a friction brake to assess the actual state of the friction brake. The actual braking test of the friction brake is preceded by a process which, for example, lies within a first phase described below.

The measurement diagram according to Fig. 1 is constructed as an x-y diagram and has an x-axis which represents a time axis and a y-axis on which a torque of the relevant friction brake is plotted. For example, the torque and the time are assigned SI units. For example, the x-axis is assigned the unit seconds "s" and the y-axis is assigned the unit newton meter "Nm".

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.

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

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

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

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

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 . At For example, at the start time xO the drive unit is not active or driving.

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.

In the first phase, when the friction partners of the friction brake are stationary and pressed against each other, the measured values Ml to M6 are recorded one after the other 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.

In the first phase, the drive power of the drive unit is gradually increased. In this phase, the 6 measured values Ml to M6 are recorded, for example, using sensors. The measured values Ml to M6 represent an increasing braking torque of the friction brake, with M6 > M5 > M4 > M3 > M2 > Ml.

For example, a second phase that 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 than two or more measured values are also possible in the second phase . Within the second phase, the slope of the measurement curve K is not "zero" or . Within the second phase, the slope of the measurement curve K is not approximately "zero".

The second phase represents a phase of the friction brake in which the friction brake is caused to slip due to an increasing drive power of the drive unit and a 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 with 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.

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

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

The third phase occurs after 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.

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

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 course lies within an upper limit such as a maximum limit and a lower limit such as a minimum limit.

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 of the braking torque measurement. During the third phase, when the drive unit is 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.

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.

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

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.

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.

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.

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 state 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 state of the friction brake.

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 spindle that can be driven in rotation, is hidden in Fig. 2 by external 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.

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.

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

reference symbol list

1 Device 2 Friction brake

3 drive unit

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 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 measurement 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 that is temporally subsequent 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 are 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 for a predetermined measuring parameter, each offset in time, 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 in such a way that they determine a starting point of the slipping state of the drive part, whereby 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 such that the number of temporally offset multiple sensor measurement values can be specified. 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 such 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 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 measurement 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 that is temporally subsequent to the static state, wherein 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. remains, characterized in that over a predetermined measuring interval which lies within a range in which the drive part is in the slipping state, a plurality of sensor measured values are recorded for a predetermined measuring parameter, each offset in time, 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 plurality of 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 measurement 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 measurement 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 measurement 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 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. 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.