METHOD FOR MONITORING A BRAKE OF AN ELEVATOR SYSTEM, BRAKE OF A DRIVE OF AN ELEVATOR SYSTEM AND ELEVATOR SYSTEM

Description

[0001] The invention relates to a method for monitoring a brake of an elevator installation, a brake of a drive of an elevator installation and an elevator installation.

[0002] Known elevator systems for transporting people or loads comprise an elevator car and a drive for moving the elevator car. The drive typically includes a brake. Brake wear is regularly checked manually, for example, using a feeler gauge. Monitoring the spring force of a braking system is known, for example, from EP 3080034 A1. JP 2012056652 A relates to an elevator system with a brake operation sensor that detects the operating status of a brake. However, the technology or sensors for monitoring brakes are often expensive or complex. Regular manual monitoring of brake wear can be error-prone or involve significant time and expense.

[0003] EP3666709A1 discloses a braking device for an elevator, a method for testing an elevator braking device, and an elevator system. The braking device comprises: a fixed member; a movable member movable between a retracted position in which the movable member is adjacent to the fixed member and separated from a braking element, and a braking position in which a friction plate of the movable member contacts the braking element and exerts a braking force on the braking element; an elastic member connected between the movable member and the fixed member; an elastic member disposed between the movable member and the fixed member; a coil disposed in the fixed member;and a controller that supplies an operating current to the coil when the elevator is in normal operation, the controller being configured to implement a test mode in which the controller supplies a test current to the coil that is less than the operating current and determines whether the movable member has been pulled to the retracted position.;

[0004] The object of the invention is to provide a method for monitoring a brake of an elevator system, which is improved over prior art methods, with the aim, in particular, of increasing the reliability of the monitoring or the safety of the elevator system, or of reducing the costs of monitoring. Furthermore, the object of the invention is to provide a brake of a drive of an elevator system and an elevator system.

[0005] This object is achieved by a method according to claim 1 and a brake and elevator system according to the subordinate claims. Advantageous further developments and embodiments emerge from the subclaims and from this description.

[0006] One aspect of the invention relates to a method for monitoring a brake of an elevator installation, wherein the brake comprises a coil for opening the brake, a brake condition sensor for determining an open or closed brake condition, and a brake pad. The method comprises closing the brake. The method comprises energizing the coil, wherein, to energize the coil, an electrical variable of the coil is set to a predetermined test value. The method comprises determining the brake condition of the brake when the coil is energized. The method comprises determining a wear indicator based on the brake condition of the brake, wherein the wear indicator indicates a wear condition of the brake pad of the brake.

[0007] A further aspect of the invention relates to a brake of a drive of an elevator installation. The brake comprises a coil configured, in an energized state, to open or not open the brake depending on an electrical variable of the coil. The brake comprises a brake state sensor configured to determine a brake state of the brake, wherein the brake state is open or closed. The brake comprises a brake controller, wherein the brake controller is configured to carry out a method according to one of the embodiments described herein.

[0008] Yet another aspect of the invention relates to an elevator installation having a drive and a brake of the drive according to one of the embodiments described herein.

[0009] According to some embodiments, the brake is designed as a holding brake, in particular for braking or holding the drive in a de-energized state of the drive or for emergency braking, for example, in the event of an interruption in the power supply of the elevator system. In some embodiments, the brake is designed as a disc brake or as a drum brake. A drive of an elevator system can, in particular, comprise two brakes according to the embodiments described herein.

[0010] In embodiments, the brake comprises a rotating body which is connected in a rotationally fixed manner to a shaft of the drive. For example, the rotating body can comprise a brake drum in the case of a drum brake, or a brake disc in the case of a disc brake. The brake can comprise a brake body. The brake body can be connected in a rotationally fixed manner to a housing of the brake relative to the rotating body. The brake body can be movable with respect to a stationary brake part or movable with respect to the rotating body. In embodiments of the brake as a disc brake, the brake body can, for example, comprise an armature disk, which can be movable in particular axially with respect to a shaft axis of the drive or a rotational axis of the rotating body. In embodiments of the brake as a drum brake, the brake body can, for example, comprise a brake arm or a brake component coupled to a brake arm.The brake component can, in particular, be designed to be movable relative to a stationary brake part or a coil of the brake. In embodiments, the brake body comprises magnetically conductive material, for example, ferromagnetic or ferrimagnetic material.

[0011] According to embodiments, the brake comprises a brake pad. The brake pad can be arranged at least partially between the brake body and the rotating body. The brake pad can be connected in a rotationally fixed manner to one of the rotating body and the brake body. The brake pad is in particular designed to be in frictional contact with the other of the rotating body and the brake body when the brake is engaged. During the course of brake operation, the brake pad can be worn from an initial thickness to a final thickness. A final thickness can be reached when the brake pad is completely worn, or a final thickness can, for example, be a minimum thickness of the brake pad specified by a manufacturer of the brake or brake pad, wherein the brake pad must be replaced once it has been worn down to the minimum thickness.

[0012] In some embodiments, the brake comprises a spring, in particular a compression spring. The spring can be configured to provide a spring force that presses the brake body toward the rotating body.

[0013] According to embodiments, the brake comprises a coil, in particular a magnetic coil. The coil can be configured to release the brake in an energized state or not to release the brake depending on an electrical variable of the coil. In embodiments, the electrical variable of the coil is a voltage applied to the coil or a current through the coil. The coil can be arranged in or on a stationary brake part. The stationary brake part can in particular be rigidly connected to a housing of the brake. The coil is in particular configured to exert a magnetic force on the brake body in an energized state. In particular, the coil can exert a magnetic force to release the brake that is greater than a spring force provided by the spring.In embodiments, the magnetic force may be directed away from the rotating body, in particular towards the stationary brake part or towards the coil.

[0014] In embodiments, the brake comprises a brake state sensor. The brake state sensor is configured to determine a brake state of the brake. The brake state can be open or closed. For example, the brake state sensor can determine an open brake state when the brake body is pulled away from the rotating body, in particular such that the rotating body is rotatable. The brake state sensor can determine a closed brake state when the brake body is pressed against the rotating body or the brake pad. The brake state sensor can be communicatively connected to a brake controller of the brake. In particular, the brake controller can be configured to receive a state signal indicating the brake state of the brake from the brake state sensor.

[0015] According to embodiments, the brake state sensor is embodied as a brake contact sensor of the brake. The brake contact sensor can, for example, comprise a push-button switch. The brake contact sensor can be arranged on the stationary brake part. The brake contact sensor can, for example, determine a closed brake state when the brake body is pressed against the stationary brake part, in particular when the brake body is in contact with the brake contact sensor. The brake contact sensor can determine an open brake state when the brake body is not in contact with the brake contact sensor, in particular when the brake body is pressed against the rotating body.

[0016] In some embodiments, the brake comprises a power module. The power module is in particular configured to energize the coil of the brake with a value of an electrical variable of the coil. The electrical variable can in particular be a voltage applied to the coil or a current flowing through the coil. In embodiments, the power module is configured to receive a value of the electrical variable of the coil specified by a brake controller of the brake and to energize the coil with the specified value. The power module can be configured to energize the coil with a predeterminable value from a value range. For example, the coil can be energized with predeterminable values ​​of a voltage from a value range between 0 V and an upper voltage value, wherein the upper voltage value can in particular be less than 300 V or less than 200 V.In particular, the power module is configured to receive a test value of the electrical quantity of the coil or a further test value of the electrical quantity of the coil from the brake controller according to embodiments described herein and to energize the coil with the test value or the further test value. In embodiments, the power module energizes the brake to open the brake during normal operation with a normal operating value of the electrical quantity. The test value of the electrical quantity (the current or the voltage) can be smaller than the normal operating value, for example, less than 80% or even less than 50% of the normal operating value.

[0017] According to embodiments, the brake comprises a brake controller. The brake controller may be configured to carry out a method according to embodiments described herein. The brake controller may comprise a processor and a memory connected to the processor, wherein the processor and the memory are configured to perform various computer-implemented functions, for example, to carry out methods, steps, calculations, or to store data according to embodiments described herein. The brake controller may comprise a communication module for communication of the brake controller with components of the brake, for example, for communication with a power module of the brake or with sensors of the brake such as a brake condition sensor, or for communication with further controllers or computer devices.A processor is understood herein to mean, in particular, a controller, a microcontroller, a microcomputer, integrated circuits of a computer, a programmable logic controller, an application-specific integrated circuit, or a programmable circuit. The memory may comprise a computer-readable medium, for example computer-readable, non-volatile memory (e.g., flash memory) or RAM (random access memory) or other storage media. The memory may be configured to store computer-readable instructions which, when executed by the processor, configure the brake controller to perform various functions, for example, to send, receive, or process signals, in particular to perform methods according to embodiments described herein.

[0018] According to embodiments, the brake body and the stationary brake part form an air gap between the brake body and the stationary brake part in the closed brake state. In the open brake state, the brake body can be pressed against the stationary brake part. In particular, the air gap can be closed in the open brake state. The width of the air gap can depend on the thickness of the brake pad. The width of the air gap can increase with the wear of the brake pad, in particular with a reduction in the thickness of the brake pad.

[0019] To open the brake from the closed brake state, a larger (minimum) value of the electrical quantity of the coil may be required as the width of the air gap increases. A relationship between the width d of the air gap and a minimum value of the electrical quantity U required to open the brake, for example the voltage, can be determined as a characteristic curve, for example as the characteristic curve U(d). The characteristic curve can be temperature-dependent. In particular, with the same width of the air gap and a higher temperature, a higher value of the electrical quantity may be required to open it. The characteristic curve of a brake can, for example, be determined at the factory, in particular to compensate for the effects of temperature on the characteristic curve or to compensate for tolerances such as material tolerances or tolerances of a coil resistance.

[0020] In embodiments, the characteristic curve comprises a starting point with an initial value of the electrical variable and an initial width of the air gap, and an end point with a final value of the electrical variable and a final width of the air gap. A brake having a brake pad with an initial thickness and an air gap with an initial width can be opened when a value of the electrical variable greater than or equal to the initial value is specified. A brake having a brake pad worn down to a final thickness and an air gap with the final width can be opened when a value greater than or equal to the final value of the electrical variable is specified. The final value is in particular greater than the initial value.

[0021] According to embodiments, methods for monitoring a brake include closing the brake. Closing the brake particularly includes specifying a value of the electrical variable of the coil by the brake controller such that the brake is in a closed brake state. The value can be specified such that the brake state sensor determines a closed brake state. For example, the value can be specified such that the coil is de-energized when the brake is closed.

[0022] According to embodiments, the method comprises energizing the coil, wherein, to energize the coil, an electrical variable of the coil is set to a predetermined test value. The electrical variable of the coil can, in particular, be a voltage applied to the coil or a current through the coil. In some embodiments, the test value can be stored in the brake controller of the brake. In embodiments, the test value is greater than the initial value of the initial point of a characteristic curve according to embodiments described herein. The test value is, in particular, less than or equal to the final value of the end point of the characteristic curve. The test value can be equal to the final value. The test value is determined based on the characteristic curve of the brake.

[0023] The characteristic curve can be factory-set. For example, the characteristic curve can be set for a low or minimum operating temperature of the brake.

[0024] According to the requirements, the characteristic curve for different temperatures is determined as a temperature-dependent characteristic curve and the test value is determined based on the temperature-dependent characteristic curve.

[0025] In some embodiments, the method may include measuring a temperature of the brake or the environment. For example, the brake may have a temperature sensor for measuring the temperature. The test value for energizing the coil may be determined based on the temperature-dependent characteristic curve and the measured temperature. For example, the test value for a predetermined test thickness or a predetermined test gap width may be determined based on the temperature-dependent characteristic curve and the temperature.

[0026] Values ​​of the electrical quantity are to be understood herein in particular as absolute values, for example as the magnitude of a voltage applied to the coil or a value of a current flowing through the coil. In embodiments, the test value is in particular smaller than a normal operating value of the electrical quantity, wherein the normal operating value is used to open the brake during normal operation of the brake.

[0027] In embodiments, the brake opens when the coil is energized with the test value if the air gap width is less than or equal to the test gap width of the air gap, and in particular if the residual thickness of the brake pad is greater than or equal to the test thickness of the brake pad associated with the test value. The brake does not open if the air gap width is greater than the test gap width, and in particular if the residual thickness of the brake pad is less than the test thickness.

[0028] In embodiments, a test thickness associated with a test value can be determined for a test value and, in particular, vice versa. For example, a test gap width associated with the test value can be determined for each test value via the characteristic curve. The sum of the width of the air gap and the thickness of the brake pad can be constant in embodiments. For example, if the initial width of the air gap and the initial thickness of the brake pad are known, the test thickness associated with the test value can be determined based on the test gap width determined using the characteristic curve. In embodiments, the test thickness is less than the initial thickness. In particular, the test thickness can be greater than or equal to the final thickness.

[0029] According to embodiments, the method comprises determining the brake state of the brake with the coil energized. During the determination of the brake state, the coil is energized, in particular, with the test value of the electrical variable. The brake state can be open or closed. The brake state can be determined, for example, by a brake state sensor according to embodiments described herein.

[0030] In embodiments, the method comprises determining a wear indicator based on the braking state of the brake, wherein the wear indicator indicates a wear state of the brake pad of the brake. In particular, the wear indicator can be determined based on the predetermined test value of the electrical variable and the braking state of the brake. The wear state of the brake pad can be a first wear state in which the brake pad is unworn or in which the brake pad has been worn down to a residual thickness that is greater than or equal to a test thickness associated with the predetermined test value. The wear state can be a second wear state in which the brake pad has been worn down to a residual thickness that is less than the test thickness.

[0031] In embodiments, the wear indicator indicates whether the brake pad is in the first wear state or in the second wear state. "Indicating" is understood herein, for example, as "indicating," "indicating," or "containing information." The wear indicator may, for example, comprise a wear value or a wear signal.

[0032] In some embodiments, the test value is predetermined such that the brake does not open when the coil is energized with the test value if a residual thickness of the brake pad is less than a test thickness. Based on a closed brake state, the wear indicator indicates that the brake pad is worn down to a residual thickness that is less than the test thickness (second wear state). In particular, the test value is predetermined such that the brake opens when the coil is energized with the predetermined test value if a residual thickness of the brake pad is greater than or equal to the test thickness. When the brake is open, the wear indicator indicates that the residual thickness of the brake pad is greater than or equal to the test thickness (first wear state).

[0033] According to some embodiments, the method comprises shutting down the elevator installation or sending a warning message if the wear indicator indicates that the brake pad has worn down to a residual thickness that is less than the test thickness (second wear state). In particular, a test value associated with the test thickness can be predetermined such that the test value lies in an end value range adjacent to the end value between the end value and the initial value. The end value range can include the end value. For example, the end value range can include a value interval of 30%, in particular a value interval of 20% or of 10% or 5%, of the difference between the initial value and the end value. In particular, a brake pad with a residual thickness less than the test thickness may require replacement.The determination of a test value or a test thickness may in particular take into account tolerances, in particular safety tolerances with regard to the final value or the final thickness.

[0034] Shutting down the elevator system can include sending a shutdown signal to an elevator controller, wherein the elevator controller shuts down the elevator system based on the shutdown signal. In a shut-down state, in particular, no passengers are transported. The elevator system can be shut down, for example, until the brake has been serviced, in particular until the brake lining has been replaced. Shutting down the elevator system when the brake lining is worn can increase the safety of the elevator system. In particular, the elevator system can be shut down regardless of possible omissions in manual monitoring.

[0035] Sending a warning message can, for example, include sending the warning message to the elevator controller. The elevator controller can store the warning message. The elevator controller can display the warning message to maintenance personnel during regular inspection or maintenance of the elevator system. In some embodiments, the elevator controller can forward the warning message to a maintenance center. Sending a warning message can be advantageous for replacing the brake pad as needed. In particular, the brake pad can be replaced before the final thickness is reached. This advantageously prevents prolonged downtime of the elevator system.

[0036] In embodiments, the method comprises determining at least one further wear indicator. A respective further wear indicator can be determined based on a brake state, which is determined when the coil is energized with a predetermined, further test value of the electrical variable. In particular, the further wear indicator indicates whether the brake pad is worn down to a residual thickness that is less than a further test thickness.

[0037] In some embodiments, the test thickness is less than the initial thickness of the brake pad and greater than the final thickness of the brake pad. A further test thickness may be less than the test thickness and in particular greater than or equal to the final thickness. The method may include sending a warning message if the wear indicator indicates that the brake pad has worn down to a residual thickness that is less than the test thickness. The method may include shutting down the elevator system if the further wear indicator indicates that the brake pad has worn down to a residual thickness that is less than the further test thickness. In exemplary embodiments, a test value associated with the test thickness or a further test value associated with the further test thickness may lie in a final value range according to embodiments described herein. For example, the further test value may be equal to the final value.

[0038] According to some embodiments, the method comprises determining the residual thickness of the brake pad based on the wear indicator and at least one further wear indicator. The residual thickness can be determined, for example, based on a plurality of wear indicators, wherein the plurality of wear indicators particularly comprises the wear indicator and the at least one further wear indicator. The wear indicators of the plurality of wear indicators can each be determined according to embodiments described herein for respective predetermined test values. In embodiments, the test values ​​can be regularly predetermined between the initial value and the final value.For example, the test values ​​of a voltage to be applied to the coil can be predetermined in steps of a maximum of 20 V, in particular of a maximum of 10 V, or of at least 1 V, in particular of at least 2 V, between the initial value and the final value, for example in steps of 5 V.

[0039] Determining the residual thickness may comprise determining a current wear interval, wherein the current wear interval borders a first test value of the test values ​​and a second test value of the test values, and wherein respective wear indicators for the first test value and the second test value indicate different wear states of the brake pad. The first test value and the second test value may be adjacent test values, in particular without a third test value between the first test value and the second test value. For example, a first wear indicator for the first test value may indicate the first wear state of the brake pad according to embodiments described herein. A second wear indicator for the second test value may indicate the second wear state of the brake pad.

[0040] Based on the current wear interval, it can be determined that the residual thickness lies within a residual thickness interval. In particular, it can be determined that the residual thickness is greater than or equal to a first test thickness associated with the first test value and less than a second test thickness associated with the second test value. Determining the residual thickness can make it possible to determine or monitor a temporal progression of the wear of the brake pad. The current wear interval, the residual thickness, or the residual thickness interval can be stored in the brake controller or an elevator controller or forwarded to a maintenance center. In embodiments, a warning message can be sent when the current wear interval reaches a final value range according to embodiments described herein.The elevator system can be shut down when the current wear interval reaches the final value or when the remaining thickness interval reaches a final thickness associated with the final value. Monitoring the brake pad wear over time can enable advance planning of brake pad replacement.

[0041] In some embodiments, the methods described herein are executed automatically. In particular, the method can be executed at least once a month, in particular at least once a week, or in particular at least once a day. The method is executed, in particular, outside of normal operation. To execute the method, the elevator installation can be switched from a normal operation mode to a brake test mode. In brake test mode, for example, no passenger transport takes place.

[0042] In embodiments, an elevator installation or a drive of the elevator installation comprises two brakes according to embodiments described herein, in particular a first brake and a second brake. Methods for monitoring the first brake and the second brake may comprise executing a method according to embodiments described herein for the first brake, wherein the second brake is closed during the execution of the method for the first brake. The method may subsequently be executed for the second brake, wherein the first brake is closed during the execution of the method for the second brake.

[0043] Embodiments described herein can offer the advantage over the prior art of improving the safety of elevator systems or the reliability of a brake in an elevator system. In particular, brake wear can be regularly checked automatically. Embodiments can replace error-prone manual inspection. The time or cost associated with manual inspection can be reduced. A further advantage of embodiments can be that brake monitoring can be provided cost-effectively. In embodiments, a replacement of the brake pads can be planned in advance or carried out as needed.

[0044] Various aspects of the invention are explained in more detail below using exemplary embodiments in conjunction with the figures, in which the figures show: Fig. 1 is a schematic sectional view of a brake according to embodiments described herein in the closed brake state; Fig. 2 is a detail of a schematic sectional view of the brake of the Fig. 1 in the open brake state; Fig. 3 shows a section of a schematic sectional view of a brake with a worn brake pad in the closed brake state; Figs. 4A-4B show schematic representations of a characteristic curve of the voltage required to open the brake as a function of the width of the air gap; and Fig. 5 shows a schematic flow diagram of a method according to embodiments described herein.

[0045] Typical embodiments are described below with reference to the figures, whereby the invention is not limited to the embodiments, but rather the scope of the invention is determined by the claims.

[0046] In the description of the figures, the same reference symbols are used for identical or similar parts. Some features that have already been described in connection with other figures are not described again for the sake of clarity. Some features that are shown multiple times or are repeated in different figures are not marked with reference symbols for the sake of clarity (for example, the shaft in Fig. 2 , reference number 112 in Fig. 1 )

[0047] Fig. 1 shows a schematic sectional view of a brake 100 according to embodiments described herein in a closed brake state. The brake 100 of the Fig. 1 is designed, for example, as a disc brake. In further embodiments, the brake can be designed, in particular, as a drum brake. The brake 100 comprises a rotating body 110, which is designed as a brake disc. The rotating body 110 is connected in a rotationally fixed, in particular rigid, manner to a shaft 112 of a drive (not shown) to be braked. The shaft 112 and the rotating body 110 are rotatable about a shaft axis 114. The terms "axial" or "radial" are to be understood in particular with reference to the shaft axis 114.

[0048] The brake 100 comprises a brake pad 130. In the Fig. 1 The brake pad 130 is new or as good as new and, in particular, not worn. The brake pad 130 has an initial thickness. The brake pad 130 is arranged axially on both sides of the rotating body 110. In particular, the brake pad 130 is connected in a rotationally fixed manner to the rotating body 110. The brake 100 comprises a brake body 120, which is connected in a rotationally fixed manner to a stationary brake part 126 of the brake 100. The stationary brake part 126 and another stationary brake part 128 are rigidly connected to a housing (not shown) of the brake 100 or the drive. The stationary brake part 126 and the another stationary brake part 128 are rigidly connected to one another, for example, via connecting elements 138. The brake body 120 is designed to be axially movable relative to the fixed brake part 126 between the brake pad 130 and the fixed brake part 126.

[0049] The brake 100 comprises springs 146 which are arranged in the Fig. 1 are arranged in the stationary brake part 126. The springs 146 exert a spring force on the brake body 120. In particular, the springs 146 press the brake body 120 axially in the direction of the rotating body 110 and the brake pad 130.

[0050] In Fig. 1 The brake 100 comprises a coil 140. The coil 140 is arranged in a coil carrier 142 in the stationary brake part 126. The coil 140 is configured to exert a magnetic force on the brake body 120 when energized. The brake body 120 comprises magnetically conductive material, for example, ferromagnetic material. When the coil 140 is energized, the magnetic force acts on the brake body 120, in particular in the axial direction toward the coil 140. In particular, the magnetic force acts in an axial direction opposite to the spring force. Fig. 1 The coil 140 is not energized and the brake 100 is in the closed braking state. The brake body 120 is pressed axially against the brake pad 130 by the spring force of the springs 146. The rotating body 110 and the brake pad 130 are clamped, in particular, between the brake body 120 and the further stationary brake part 128. The shaft 112 can be braked by the frictional contact of the brake pad 130 with the brake body 120 and the further stationary brake part 128. In particular, the shaft 112 can be held in an angular position or, in the event of an emergency braking, can be braked from a rotational movement to a standstill.

[0051] Coil 140 is energized by a power module 152 of brake 100. Power module 152 is configured to energize coil 140 with a value of an electrical variable of coil 140. For example, power module 152 is configured to apply a voltage with a voltage value, for example, a test value, to coil 140 to energize coil 140. The value of the electrical variable can be specified to power module 152 by a brake controller 150 of brake 100. For example, power module 152 is configured to apply a voltage value specified by brake controller 150 from a value range of 0 V to 200 V.Depending on the value of the electrical quantity, the current flowing through the coil 140 can generate a magnetic force which is sufficient or insufficient to pull the brake body 120 away from the rotating body 110 and towards the stationary brake part 126 against the spring force provided by the springs 146.

[0052] A brake state sensor 144 of the brake 100 is configured to determine a closed or open brake state of the brake 100. In Fig. 1 The brake condition sensor 144 is designed as a brake contact sensor with a push-button switch. The brake condition sensor 144 is arranged in the stationary brake part 126. In particular, the push-button switch of the brake condition sensor 144 is arranged at an axial boundary surface of the stationary brake part 126 in the direction of the brake body 120. The brake condition sensor 144 is configured to determine a contact between the stationary brake part 126 and the brake body 120, in particular a contact between the brake condition sensor 144 and the brake body 120. For example, in Fig. 1 the brake body 120 is not in contact with the brake condition sensor 144 or the stationary brake part 126. The brake condition sensor 144 determines in the Fig. 1 for example, a closed brake state of the brake 100. The brake state sensor 144 is connected to the brake controller 150, in particular communicatively connected. In particular, the brake controller 150 is configured to receive a state signal indicating the brake state of the brake from the brake state sensor 144. The brake controller 150 is configured to carry out a method for monitoring the brake 100 according to embodiments described herein, for example, a method 500 as described in connection with Fig. 5 described.

[0053] In Fig. 1 An air gap 122 is formed between the stationary brake part 126 and the brake body 120 in the closed brake state. For a brake pad 130 with the initial thickness, the air gap has, in particular, an initial width d 0 .

[0054] Fig. 2 shows a section of the sectional view of the brake 100 of the Fig. 1 in an open brake state. In Fig. 2 The coil 140 is energized with a value of the electrical quantity such that the brake body 120 is drawn toward the stationary brake part 126 in the axial direction toward the coil 140. In particular, a magnetic force generated by the energized coil 140 is stronger in the axial direction than the spring force of the springs 146. For a brake pad 130 with the initial thickness, the coil 140 requires at least an initial value U 0 of the electrical quantity U to open the brake 100.

[0055] In the open brake state, the brake 100 has a closed air gap 224. The brake body 120 presses in the axial direction on the push button switch of the brake condition sensor 144. The brake condition sensor 144 or the brake controller determines based on a push button signal in Fig. 2 an open brake state. The rotating body 110 is rotatable about the shaft axis 112 and, in particular, is not in frictional contact with the brake body 120 or the further stationary brake part 128.

[0056] Fig. 3 shows a section of the sectional view of the brake 100 in a closed brake state, wherein the brake pad 130 is in comparison to Fig. 1 is partially worn by the operation of the brake 100. In particular, the thickness of the brake pad 130 is reduced from an initial thickness of the brake pad 130 ( Fig. 1 ) to a residual thickness. Below the thickness of the brake pad 130 is in the Figuren 1-3 in particular, the sum of the axial partial thicknesses of the partial linings of the brake pad 130 arranged on both sides of the rotating body 110. Due to the smaller residual thickness of the brake pad 130 compared to the initial thickness ( Fig. 1 ) is the width of the air gap 326 in Fig. 3 compared to the initial width d 0 ( Fig. 1 ) is increased. In particular, to open the brake 100 from the closed brake state, a higher (minimum) value of the electrical quantity than the initial value U 0 for the coil 140 is required.

[0057] The relationship between the width d of the air gap 122,326 and a minimum value of the electrical quantity U required to open the brake 100, for example the voltage at the coil 140, is shown in the Figuren 4A und 4B as characteristic curves 400,401. The electrical quantity U is, in another embodiment (not shown), the current through the coil 140. The characteristic curves 400, 401 can be determined at the factory. The characteristic curve 400 in Fig. 4A is temperature-dependent and is determined, for example, for a temperature of 5°C (410), 20°C (420), and 40°C (430). In embodiments, the one or more test values ​​can be determined in a temperature-dependent manner based on a temperature-dependent characteristic curve. In further embodiments, a characteristic curve for a temperature, for example, the characteristic curve 410 for 5°C, can be used to predetermine one or more test values ​​for methods according to embodiments described herein.

[0058] Fig. 4B shows a characteristic curve 401 of the brake 100. During operation of the brake 100, an unworn brake pad 130 of the brake 100 has an initial thickness. In the closed brake state, the air gap 122 of the brake 100 has an initial width d 0 . As in Fig. 4B As shown, at least an initial value U 0 of the electrical quantity U is required at a starting point of the characteristic curve 401 to open the brake 100 with an air gap 122 having the initial width d 0. In this exemplary embodiment, the electrical quantity U is a voltage applied to the coil 140 of the brake 100. In another exemplary embodiment (not shown), the electrical quantity is a current flowing through the coil 140 of the brake 100. Due to wear or tear of the brake pad 130, the thickness of the brake pad 130 is reduced during operation of the brake 100 and the width d of the air gap is increased. With increasing wear of the brake pad 130 and increasing width d of the air gap, a higher value or minimum value of the electrical quantity U is required to open the brake 100. A permissible final thickness may be specified for the brake pad 130.In particular, it can be provided that the brake pad 130 is to be replaced at the latest when it has worn down to its final thickness. At an end point of the characteristic curve 401, the brake pad 130 is worn down to its final thickness and the air gap has a final width d F . To release the brake, a final value UF of the electrical quantity associated with the final thickness is required.

[0059] Fig. 5 shows a method 500 for monitoring a brake of an elevator installation. At 510, the method 500 comprises closing the brake. In particular, a coil of the brake is de-energized. At 520, the coil is energized. To energize the coil, an electrical variable of the coil is set to a predetermined test value. The test value is predetermined based on a characteristic curve of the brake. For example, at 520, the test value U 1 of the Fig. 4Bused to energize the coil. Values ​​of the electrical quantity greater than or equal to the test value U 1 are suitable for opening the brake with an air gap of the test width d 1 , wherein the brake in particular has a brake pad with a test thickness associated with the test value. The test value U 1 can be close to the final value UF, for example, in a final value range according to the embodiments described herein.

[0060] At 530, method 500 includes determining a brake state. The brake state is determined, in particular, by a brake state sensor. The brake state can be open or closed. At 540, a wear indicator is determined based on the brake state. If at 540 the brake state is closed (546), the wear indicator indicates at 548 that the remaining thickness of the brake pad is less than the test thickness (second wear state). At 560, a warning message is sent, in particular to a maintenance center. The warning message indicates that the brake pad of the brake needs to be replaced. In further embodiments, the elevator installation can be shut down instead of sending a warning message.

[0061] If the brake state is open at 540 (542), the wear indicator at 544 indicates that the residual thickness of the brake pad is greater than or equal to the test thickness (first wear state). At 550, the procedure 500 can be terminated or repeated for another test value.

[0062] The method can be repeated, in particular, for a further test value to determine a further wear indicator. When repeating the method for the further test value, instead of sending the warning message, the elevator system is shut down if the further wear indicator indicates a second wear condition. A value between the test value U 1 and the final value UF is predetermined, for example, the final value UF , as the further test value.

[0063] Embodiments described herein may reduce the time, personnel, or costs required to maintain or monitor brakes in elevator systems. Furthermore, embodiments may increase the reliability or safety of elevator systems.

Claims

1. A method (500) for monitoring a brake (100) of an elevator system, the brake (100) comprising a coil (140) for opening the brake (100), a brake state sensor (144) for determining an open or closed brake state, and a brake pad (130), and the method (500) comprising: - closing the brake (100); - energizing the coil (140), an electrical variable of the coil (140) being set to a predetermined test value for energizing the coil (140); - determining the brake state of the brake (100) when the coil (140) is energized; and - determining a wear indicator on the basis of the brake state of the brake (100), the wear indicator indicating a wear state of the brake pad (130) of the brake (100), the test value being predetermined such that the brake (100) does not open when the coil (140) is energized with the test value if a residual thickness of the brake pad (130) is less than a test thickness; and the wear indicator, based on a closed brake state, indicating that the brake pad (130) is worn down to a residual thickness which is less than the test thickness, characterized in that - the brake state sensor (144) is designed as a brake contact sensor of the brake (100), and - the test value for different temperatures is determined on the basis of a temperature-dependent characteristic curve of the brake.

2. The method (500) according to claim 1, wherein the electrical variable of the coil (140) is a voltage applied to the coil (140) or a current through the coil (140).

3. The method (500) according to either of the preceding claims, wherein the method (500) is carried out automatically at least once a month, in particular at least once a week, in particular once a day.

4. The method (500) according to any of the preceding claims, wherein the test value is stored in a brake controller (150) of the brake (100).

5. The method (500) according to any of claims 1 to 4, wherein the brake pad (130) wears from an initial thickness of the brake pad (130) to a final thickness of the brake pad (130) due to wear; and wherein the test thickness is less than the initial thickness.

6. The method (500) according to any of claims 1 to 5, wherein the method (500) comprises: - shutting down the elevator system and / or sending a warning message if the wear indicator indicates that the brake pad (130) has worn down to a residual thickness which is less than the test thickness.

7. The method (500) according to any of claims 1 to 6, wherein the method (500) comprises determining at least one further wear indicator; wherein a particular further wear indicator is determined on the basis of a brake state which is determined when the coil (140) is energized with a predetermined, further test value of the electrical variable; and wherein the further wear indicator indicates whether the brake pad (130) has worn down to a residual thickness which is less than a further test thickness.

8. The method (500) according to claim 7, wherein the brake pad (130) wears from an initial thickness of the brake pad (130) to a final thickness of the brake pad (130) due to wear; wherein the test thickness is less than the initial thickness and more than the final thickness; wherein a further test thickness is less than the test thickness; and wherein the method (500) comprises: - sending a warning message if the wear indicator indicates that the brake pad (130) has worn down to a residual thickness which is less than the test thickness; and - shutting down the elevator system if the further wear indicator indicates that the brake pad (130) has worn down to a residual thickness which is less than the further test thickness.

9. The method (500) according to either of claims 7 and 8, wherein the method (500) comprises: - determining the residual thickness of the brake pad (130) on the basis of the wear indicator and the at least one further wear indicator.

10. A brake (100) of a drive of an elevator system, comprising a coil (140) which is configured to open the brake (100) or not to open the brake (100) in an energized state depending on an electrical variable of the coil (140); a brake state sensor (144) which is configured to determine a brake state of the brake (100), wherein the brake state is open or closed; and a brake controller (150), wherein the brake controller (150) is configured to carry out a method according to any of the preceding claims.

11. The brake (100) according to claim 10, wherein the brake (100) comprises a power module (152), wherein the power module (152) is configured to receive a test value of the electrical variable of the coil (140) or a further test value of the electrical variable of the coil (140) from the brake controller (150) and to energize the coil (140) with the test value or the further test value.

12. The brake (100) according to either of claims 10 and 11, wherein the brake (100) is designed as a disk brake or as a drum brake.

13. An elevator system, having a drive and a brake (100) of the drive according to any of claims 10 to 12.