Method for determining the wear state of components of a suspension structure of an elevator installation

Abstract

A method and a monitoring device for determining the wear state of components of a suspension structure (5) of an elevator installation (1) are introduced. The components are, for example, a rope-like suspension (5), a drive wheel disk (17) of a drive machine (19), and deflection rollers (27, 29). The method at least comprises the following steps: monitoring the actual course of a first parameter varying over time, which course is associated with the wear state of at least one monitored first component in the components, comparing the monitored actual course of the first parameter varying over time with a pre-determined expected course of the first parameter varying over time; and determining the wear state of the monitored component based on the result of the comparison.

Description

Technical Field

[0001] The present invention relates to a method for determining the wear state of components of a suspension structure in an elevator installation. Furthermore, the present invention relates to a monitoring device for performing or controlling such a method, a computer program product for programming such a monitoring device, and a computer-readable medium having such a computer program product. Background Art

[0002] In an elevator installation, a suspension structure serves to move an elevator car and, if necessary, a counterweight within an elevator shaft, and is also typically used to hold the weights of the elevator car and the counterweight.

[0003] Typically, the suspension structure includes a number of elongate, flexible suspension means, such as ropes, belts or bands. A rope can consist of a large number of wires or strands, which are usually made of metal, in particular of steel. A belt or band can also have wires or strands, for example made of steel or fiber material, as load-bearing elements, which are accommodated in a matrix material such as a polymer or an elastomer.

[0004] Depending on the type of suspension implemented in the elevator installation, these suspension means can be anchored to the elevator car and / or the counterweight to hold the elevator car and the counterweight. Alternatively, the suspension means can be anchored in the elevator shaft, for example at the top of the shaft, and the elevator car and / or the counterweight can be held by deflection rollers mounted on the suspension means, which are usually also referred to as pulleys.

[0005] Here, the suspension means are usually moved by a drive machine so that the elevator car and the counterweight held by the suspension means can move in opposite directions within the elevator shaft. Here, the suspension means usually run on a drive sheave that is rotationally driven by the drive machine. Depending on the suspension means used, the drive sheave can have a surface with a defined profile. For example, the drive sheave for the suspension means can be designed in the form of a rope having grooves extending in the circumferential direction, into which the rope can be inserted in order to achieve sufficient traction between the drive sheave and the rope. In the case of a suspension means in the form of a belt or band, the suspension means can have a surface with a defined profile, such as a V-shaped tooth surface, and the drive sheave can have a complementary defined profile surface on its outer side.

[0006] The components mentioned, namely in particular the suspension means, the drive machine with its drive sheave, the deflection rollers and the anchoring means of the suspension means, as well as other components, can together form the suspension structure.

[0007] During the operation of the elevator installation, the components of the suspension structure usually wear.

[0008] For example, the sling will gradually lose its mechanical load capacity due to friction with the drive wheel disc or deflection wheel and / or frequent bending during the deflection of the drive wheel disc or deflection wheel. Here, wear may be the result of surface wear of the material and / or material fatigue and possible material fracture. Wear of the sling generally causes changes in its physical properties. In particular, wear of the sling causes a reduction in the load-bearing capacity of these slings. In the worst case, the sling may tear. In addition, wear of the sling affects its elasticity. For example, the sling becomes more elastic or softer over time, making it difficult, for example, to precisely position the elevator car held thereon using these slings.

[0009] Wear signs may also appear on the drive wheel disc and deflection wheel. For example, the outer side profile of these components may change its structure over time, especially due to wear. Changes caused by wear of the drive wheel disc or deflection wheel particularly lead to changes in the frictional engagement between these components and the sling driven or guided by them. For example, the slip between the drive wheel disc and the driven sling increases over time due to wear, especially in the case where the tensile modulus of the sling changes. In addition, as the diameter of the sling decreases, the conveying radius decreases, and for the same travel distance between two determined floors, more revolutions of the drive wheel disc are required during the service life.

[0010] There may also be various other types of wear signs, which may cause other types of changes in the physical properties of the sling structure.

[0011] To limit or monitor the wear of components within the elevator equipment, especially the wear of components of the sling structure, various methods have been developed. Some such methods are described in EP3130555A1, CN104627762A, WO2018 / 139434A1, CN109987480A, JP2011-132010A, EP2299251A1, EP0849208A1, JP2011-126710, WO2019 / 081412A1, WO2003 / 035531A1, WO2007 / 141371A2, JP2019-085242A, EP2628698B1, and WO2016 / 040452A1. Summary of the Invention

[0012] There is a primary need for a method that can be used to more efficiently, reliably, and / or cost-effectively monitor wear on components of the sling structure. In addition, there may be a need for a monitoring device configured to perform or control such a method, a corresponding computer program product, and a computer-readable medium storing the computer program product.

[0013] According to a first aspect of the present invention, a method for determining the wear state of a component of a suspension structure of an elevator installation is provided, the method having at least the following method steps, preferably in the order given below:

[0014] Monitoring the actual course of a first parameter over time, which course is associated with the wear state of at least one monitored first component in the component;

[0015] Comparing the monitored actual course of the first parameter over time with a predetermined expected course of the first parameter over time;

[0016] Determining the wear state of the monitored component based on the result of the comparison.

[0017] According to a second aspect of the present invention, a monitoring device for determining the wear state of a component of a suspension structure of an elevator installation is provided, the monitoring device being configured to perform or control an embodiment of the method according to the first aspect of the present invention.

[0018] According to a third aspect of the present invention, a computer program product is provided, which computer program product comprises computer-readable instructions, which, when executed on a computer, in particular on a monitoring device which can be programmed in a computerized manner according to the second aspect of the present invention, initiate the execution or control of the method according to an embodiment of the first aspect of the present invention.

[0019] According to a fourth aspect of the present invention, a computer-readable medium is provided, on which the computer program product according to the third aspect of the present invention is stored.

[0020] Feasible features and advantages of embodiments of the present invention can be considered to be based on the concepts and cognitions described below, including but not limited to the present invention.

[0021] In traditional solutions, the wear of components of the suspension structure should be monitored, and usually parameters that enable inferences about this wear are monitored. For example, the dimensions of the suspension, i.e., the diameter of the rope, for example, are monitored. As other examples, it is also possible to monitor the surface structure on the drive pulley or deflection roller, the magnetic flux through the suspension, the tensile properties of the suspension, or the slip between the suspension and, for example, the drive pulley. Here, the current wear state of the corresponding component is usually inferred based on the current measured value of the parameter. For example, the current measured value is compared with a predetermined limit value, and if the limit value is exceeded or not reached, it is inferred that the monitored component has reached a critical wear state.

[0022] In contrast, in the solution presented here, a single measurement of a parameter at a single point in time should not be used to determine the wear state of a component of the spreader structure. Instead, the trend of the parameter over time should be monitored. In other words, how the monitored parameter changes over time should be tracked. For this purpose, the monitored parameter is usually measured continuously or at time intervals (e.g., regularly), and the obtained measurement values are tracked, i.e., for example, the measurement values are stored.

[0023] The trend of the parameter determined in this way over time should not be compared with a single limit value or the like as in the case of traditional solutions. Instead, the determined trend over time should be compared with a pre-determined expected trend of the parameter over time.

[0024] The expected trend of the parameter over time can be determined in advance, for example, based on experiments, data collected from other elevator equipment and their spreader structures, simulations, etc. Alternatively or in addition, the expected trend of the parameter over time can also be determined based on the previously observed trend of the parameter on the same component, i.e., for example, by extrapolating the previously determined trend of the parameter.

[0025] By comparing the actual trend of the monitored parameter over time with the pre-determined expected trend of the parameter over time, information about the current wear state and / or, if necessary, also about the future wear state of the observed component of the spreader structure can be determined.

[0026] This solution is based on the following observation: In some cases, the wear state of a component of the spreader structure may not be reflected in the current physical properties of the component, and thus can be determined by measuring a parameter associated therewith, or in some cases, information about the future wear state cannot be obtained solely from the parameter measured at a single point in time. Instead, it has been observed that monitoring the time-varying behavior of the physical properties of these components can lead to more reliable and / or more accurate inferences about the current wear state, especially the future wear state, of the components.

[0027] The parameter to be monitored within the scope of the solution presented here with respect to its actual trend over time should be associated with the wear state of at least one first monitored component among a plurality of components in the spreader structure. This association can be expressed as the parameter changing its value according to the current wear state of the monitored component, preferably in a uniquely determined manner or in a one-to-one correspondence.

[0028] Since in some embodiments other parameters can be advantageously monitored, as will be explained in more detail below, in all embodiments the parameter to be monitored is referred to herein as the first parameter, and in some embodiments, as a complement to the other parameters to be monitored, as the second parameter.

[0029] According to one embodiment, the first parameter to be monitored is selected from a group of parameters including:

[0030] The length of the sling,

[0031] The stretching characteristics (reversible and / or irreversible) of the sling,

[0032] The radial dimension of the sling,

[0033] The optical characteristics of the sling structure,

[0034] The magnetic characteristics of the sling structure,

[0035] The electrical characteristics of the sling structure,

[0036] The mechanical stress of the sling,

[0037] The dimensions of the structure of the contact surface of the drive sheave,

[0038] The slip occurring between the contact surface of the sling and the drive sheave, and

[0039] The force exerted by the sling on the anchor, in particular also

[0040] The time-varying trend of the vibration or micro-acceleration, which can correspond to the sling based on its structure, for example, the displacement of the rope lay length, and in particular

[0041] The change in the natural frequency of the elevator system (elevator car and / or counterweight) in the longitudinal direction of the shaft at a given position (due to the acceleration sensor, the mass of the elevator car remains constant, so it is related to the belt), and in particular

[0042] Evaluating the re-calibration of the elevator car, and in particular

[0043] The ambient temperature (the main cause of plastic aging), and in particular

[0044] The humidity (the main cause of plastic aging).

[0045] Each of the parameters mentioned is to a certain extent associated with the current wear state of the components of the sling structure. In the best case, the parameter or its trend over time is also associated with the future wear state of the components. The individual parameters can be measured in different ways and can be associated with the wear state of the same or different components of the sling structure in different ways. The parameters mentioned can be measured relatively easily and / or precisely, preferably using measuring devices that are simple in structure and thus more economical and / or are already provided in the elevator installation.

[0046] The length of the sling, i.e. the distance between the ends of the sling that are anchored, for example, in the elevator shaft or on one of the components that needs to move together with the sling structure, usually depends to a large extent on the wear state of the sling. Usually, the length of the sling increases with increasing wear. The length of the sling can be measured directly or indirectly in different ways. For example, when the elevator car is at the top floor, the distance between the counterweight held by the sling structure and the buffer provided at the bottom of the elevator shaft can be measured. The longer the sling, the smaller this distance. This distance can be measured relatively easily, and thus an accurate inference about the current length of the sling can be made.

[0047] The stretching properties of the sling, i.e. the case where the sling can extend in response to a force applied thereto, also depend to a large extent on the wear state of the sling. The stretching properties of the sling can be reflected by its modulus of elasticity. The stretching properties can refer to tensile elasticity and / or bending elasticity. The stretching properties can be measured directly, for example by measuring the change in length of the sling under a known mechanical load. For example, the stretching properties of the sling can also be determined directly using strain gauges mounted on the sling. Alternatively or in addition, the stretching properties can be measured indirectly, for example by monitoring the intensity and / or frequency at which so-called leveling compensation must be performed. Through this leveling compensation, the elevator car stops at the target position and then changes its level, i.e. the height of the elevator car in the elevator shaft, due to the associated length change of the sling when the elevator car is loaded or unloaded. Then, the change in level is compensated by appropriately displacing the sling structure using the drive machine. The intensity and / or frequency at which this leveling compensation must be performed can enable an inference about the current stretching properties of the sling.

[0048] In addition, the amount of stretch and accordingly also the modulus of elasticity are associated with the natural frequency of the system. Therefore, by measuring the natural frequency, the modulus of elasticity can be inferred, and vice versa, by determining the modulus of elasticity, the natural frequency can be inferred.

[0049] The radial dimensions of a sling, such as the diameter of a rope or the thickness of a belt, decrease over time due to wear and tear, especially abrasion, and thus represent a reliable measure for determining the current wear state of the sling. The radial dimensions of the sling can be measured directly or indirectly. For example, an optical sensor can be used to determine the radial dimensions. A situation where the radial dimensions of the sling decrease beyond a certain level may indicate that the sling is scrapped, i.e., the sling should be replaced.

[0050] The optical properties of the sling also change over time due to wear. For example, increased wear may change the color, reflectivity, and / or optically recognizable structures, such as surface roughness or macroscopic structures on the surface of the sling, such as in the form of protruding wires forming a rope. Therefore, measuring the optical properties of the sling enables relatively simple inferences to be drawn about its wear state. Suitable sensors (such as optical sensors, photodiodes, cameras, etc.) can be used to monitor the optical properties of the sling.

[0051] The magnetic properties of the sling are also usually closely associated with its wear state. Especially in the case of ferromagnetic slings, increased wear has a significant impact on the magnetic flux appearing in the suspension elements. By relatively easily measuring the magnetic flux passing through the sling, inferences can be drawn about its wear state.

[0052] In many cases, the electrical properties of the sling are also affected by its wear state. Especially in the case of slings with good electrical conductivity, such as steel cables or belts with load-bearing core wires, increased wear has a significant impact on the resistance generated by the sling. For example, as wear increases, a break or crack in one of the many core wires in the sling causes the resistance experienced by the current conducted through the sling to increase over time. By relatively simply measuring the resistance passing through the sling, inferences can be drawn about its wear state.

[0053] The mechanical stress acting on the sling during the operation of the elevator equipment may also depend on the wear state of the sling. Especially for the typical case where multiple slings are used to hold and shift the elevator car and the counterweight, wear has the effect that the lengths of some slings change more than those of other slings. Therefore, the forces that each sling has to bear and thus the mechanical stress acting on the sling change over time. This mechanical stress can be relatively easily measured, and thus inferences can be drawn about signs of wear.

[0054] Although the parameters discussed above mainly relate to the determination of the wear state of the sling, other parameters can be monitored in order to be able to identify wear on other components of the sling structure.

[0055] For example, the dimensions of the structure of the contact surface of the drive sheave change as wear increases. On its contact surface, i.e., usually on its outer side where the spreader structure contacts the drive sheave, the drive sheave can have structures such as grooves, recesses, webs, axial side boundaries, etc. These structures can be designed to move the spreader and / or laterally guide the spreader with a desired traction force or a desired amount of slip with the help of the drive sheave. Over time, these structures are worn out due to wear, i.e., the dimensions of these structures change. For example, the grooves on the outer side of the drive sheave wear out over time, especially these grooves become rounded or the depth of the grooves changes. Therefore, by monitoring the dimensions of such a structure, inferences can be drawn about the wear state of the drive sheave. Since the drive sheave also interacts with the spreader structure, the wear state of the spreader structure can also be indirectly inferred if necessary.

[0056] Due to wear, the amount of slip that occurs between the contact surfaces of the spreader and the drive sheave also changes over time. This can occur due to the dimensional changes of the structures on the contact surface of the drive sheave mentioned above. However, there may also be other wear-related causes, for example, due to over-lubrication and / or using the wrong lubricant, there is increasing contamination on the drive sheave and / or the spreader, for example. The amount of slip can be easily measured directly or indirectly. For example, the car travel distance traveled by the elevator car during travel can be compared with the drive sheave travel distance or the pulley travel distance, i.e., compared with the distance traveled by the outer side of the drive sheave or the deflection sheave during travel.

[0057] Wear of the spreader structure may also cause a change in the force exerted by the spreader on its anchor. The possible wear-related changes in terms of mechanical stress in the spreader mentioned above also affect the anchoring of the spreader. If the spreader stress deviates excessively from the target value, re-tensioning of the spreader will be required. Otherwise, unequal spreader stress will result in unequal or uneven wear signs, for example, in the elevator installation, for example, on the guide shoes of the elevator car and / or the counterweight. In addition, unequal spreader stress may also cause the spreader to jump on the drive sheave and / or the turning rollers and / or cause the turning rollers to be in a skewed position on the elevator car or the counterweight. Eventually, an increase in wear signs on the components of the spreader structure can be caused and thus confirmed.

[0058] For example, by means of a so-called intelligent fixing point, the forces exerted by the spreader structure on its anchoring elements can be determined. Here, the fixing of the spreader at the top of an elevator shaft, for example, serves not only to mechanically hold the spreader. Instead, the fixing device is also equipped with suitable technical means in order to be able to determine the forces exerted by the spreader on the fixing. The forces or stresses determined in the fixing or the anchoring elements can be determined with sufficient accuracy with relatively little effort in order to draw conclusions about the wear state within the spreader structure, in particular to be able to draw conclusions about the wear state of the individual components of the spreader structure.

[0059] According to one embodiment of the invention, the proposed method further comprises the following steps:

[0060] Monitoring the actual course over time of a second parameter, the course of which influences and / or is associated with the wear state of at least one monitored component of the component, wherein the second parameter is different from the first parameter;

[0061] Based on the comparison result of the actual course over time of the monitored first parameter with the pre-determined expected course over time of the first parameter, and based on the monitoring result of the actual course over time of the monitored second parameter, to determine the wear state of the monitored first component.

[0062] In other words, in addition to monitoring the actual course over time of the first parameter, it is also possible to monitor another second parameter with respect to its actual course over time. For example, the second parameter can reflect a physical property of one of the components of the spreader structure, which is associated with the wear state of the corresponding monitored component in a similar way to the case of the first parameter. Alternatively or in addition, the second parameter can influence the wear state of the monitored component, i.e., the second parameter can reflect the physical property that affects how the wear in the associated component changes over time. Thus, the second parameter can reflect a physical property that is not necessarily a property of the associated component itself, but rather a property of the environmental conditions or boundary conditions under which the component operates, which also affect the wear of the component.

[0063] Here, the component whose wear state is affected by or associated with the influence of the second parameter can be the same component as the first component, the wear state of which is associated with the first parameter monitored according to the method. However, the components can also be different from each other.

[0064] Then, based on two monitored parameters, namely the actual trend of the first parameter over time and the actual trend of the second parameter over time, the wear state of the monitored first component can be determined. In other words, information regarding the current and / or future wear state of the first component can be derived based on the actual trend of the first parameter over time and the comparison of this trend with a predefined expected trend of the first parameter over time corresponding thereto, and based on the actual trend of the second parameter over time.

[0065] By considering the actual trends of two different parameters over time, various advantageous effects can be achieved, which can have a positive impact on the reliability, accuracy, and / or other characteristics of the information determined regarding the wear state of the component.

[0066] For example, according to one embodiment, the first parameter and the second parameter can be associated with the wear state of the monitored first component in different ways.

[0067] In other words, the wear state of the monitored first component can affect or be affected by the first and second parameters in different ways. Although both parameters are subsequently associated with or affect the wear state of the monitored component, the qualitative and / or quantitative correlations between the two parameters may be different. Therefore, by measuring these two parameters, on the one hand, a certain degree of redundancy in the determination scheme for the wear state can be achieved. On the other hand, the different types of associations with the wear state can enable a more accurate overall judgment of the wear state.

[0068] According to another embodiment of the method, the first parameter and the second parameter can be associated with the wear state of the monitored first component in a mutually (alternatively) acting manner.

[0069] In other words, in this method, the two parameters to be monitored in terms of their actual trends over time can be advantageously selected in such a way that the characteristics represented by these two parameters interact, that is, influence each other. In particular, the parameters can be selected in such a way that the change in the second parameter affects the wear of the component monitored by the second parameter in a way that can be detected by means of the first parameter.

[0070] For example, the ambient temperature in an elevator shaft housing a spreader can be measured as the second parameter. This ambient temperature typically affects the wear occurring on the spreader. Then, the wear state of the spreader can be determined, for example, based on a first parameter associated with the wear state of the spreader, such as the length or modulus of elasticity of the spreader to be measured, and, as a supplement, the ambient temperature of the spreader can also be taken into account.

[0071] In another example, for instance, the ambient temperature and the slip behavior of a belt are correlated.

[0072] According to one embodiment, based on the measurement results of the monitored second parameter, a predetermined expected time-varying trend of the first parameter can be selected from multiple feasible predetermined expected time-varying trends of the first parameter.

[0073] In other words, it can be known in advance that the physical property reflected by the second parameter generally affects the time-varying trend of the wear occurring in the components of the spreader structure in a predetermined manner. This can be determined in advance through experiments, observations of existing elevator equipment, and through calculations or simulations. Therefore, the expected time-varying trend of the first parameter associated with such wear may vary depending on how the physical property reflected by the second parameter actually occurs.

[0074] By measuring the second parameter and monitoring its actual time-varying trend, a more accurate prediction or a more accurate hypothesis can be made about the expected time-varying trend of the first parameter. By being able to compare the monitored actual time-varying trend of the first parameter with the more precisely predetermined expected time-varying trend of the first parameter in this way, more reliable and / or more accurate information about the wear state of the monitored component can be derived overall.

[0075] In the above embodiment, the second parameter to be monitored can specifically be selected from a group of parameters, including:

[0076] The temperature in the area of the spreader structure,

[0077] The air humidity in the structural area of the spreader, and

[0078] The air pressure in the area of the spreader structure.

[0079] In other words, as a variant of the above embodiment, the second parameter to be monitored can be the temperature in the area of the spreader structure, that is, for example, the air temperature present in the elevator shaft or the temperature measured directly on one of the components of the spreader structure. This temperature generally affects the wear occurring on the spreader structure over time. Wear generally increases with the increase in temperature. Here, it would be advantageous for the proposed method that the temperature is not measured at a single point in time and then an attempt is made to draw inferences about the wear, but rather the time-varying trend of the temperature is monitored. Information about the time-varying trend of the temperature or the average temperature calculated therefrom over a period of time enables a more accurate judgment of the wear that is generally to be assumed during that period, and thus a more accurate judgment of the expected time-varying trend of the first parameter.

[0080] By comparing the determined time-varying actual trend of the first parameter with the temperature-related expected time-varying trend of the first parameter, a judgment on the current wear state of the monitored component can then be determined with relatively high accuracy. For example, the state of the outer side of a sling covered with plastic that shows signs of aging can be determined in this way.

[0081] It is even possible to determine a judgment on the future wear state of the component. For example, if the time-varying actual trend is consistent with the expected time-varying trend within an acceptable tolerance, then extrapolation over time can be used to infer future time points at which the wear will exceed the acceptable level. For example, this information can be used to plan the maintenance work of the elevator equipment in advance. Thereby, the workload and / or cost can be saved.

[0082] Alternatively or in addition, the second parameter to be monitored can be the humidity in the area of the sling structure. The existing humidity also generally has an impact on the wear occurring in the sling structure. For example, increased humidity can cause greater wear, such as due to corrosion phenomena. In this case, inferences can also be drawn based on the actual time-varying trend of the air humidity or the average value derived therefrom regarding how the wear will occur during the observation period and thus which time-varying trend of the first parameter can be expected. Then, the actual time-varying trend of the first parameter can be compared again with the expected time-varying trend of the first parameter pre-determined based on the second parameter.

[0083] As another alternative, the second parameter to be monitored can be the air pressure in the area of the sling structure. The air pressure existing during the observation period also has an impact on the wear occurring in the sling structure, so the information on the actual time-varying trend of the air pressure can be used to approximately pre-determine the expected time-varying trend of the first parameter pair.

[0084] Alternatively or in addition, in the previously described embodiments, the second parameter to be monitored can specifically represent the running frequency of the elevator car moved by the sling structure.

[0085] The frequency at which the elevator car moves by means of the sling structure during the observation period of course also has an impact on the wear signs appearing on the sling structure. By observing as the second parameter the frequency at which the elevator car moves per unit time or within a certain period of time since the start of the observation, information can be obtained that can be used to pre-determine the expected time-varying trend of the first parameter, so that the actually observed time-varying trend of the first parameter can be compared again with the expected time-varying trend in order to be able to draw inferences about the wear state of the monitored component.

[0086] Here, it may also be considered how far the observed travel distances are, i.e., how long the travel distances are, how much nominal load has been transmitted respectively during the observed travel distances and / or other parameters that may affect the wear occurring during the travel. In addition, as a supplement to the monitoring of the driving frequency, other parameters can also be monitored as the second parameter, such as the already explained temperature, humidity and / or air pressure in the area of the spreader structure.

[0087] According to one embodiment, the wear state can be determined based on the deviation of the actually measured time-dependent trend of the monitored first parameter from the pre-determined expected linearly time-dependent trend of the first parameter.

[0088] In other words, the actually measured time-dependent trend of the monitored parameter and the pre-determined expected time-dependent trend of the first parameter can be compared continuously or at certain time intervals. Here, for the pre-determined time-dependent trend, a linear change trend can be assumed, i.e., this change trend can be based on the fact that the characteristic represented by the first parameter of the monitored component of the spreader structure changes linearly over time. Here, by the way that the actually measured time-dependent trend of the monitored first parameter is different from the pre-determined expected linearly time-dependent trend of this first parameter, it is possible to draw inferences about the current or future wear state.

[0089] For example, in many cases or over a longer period of time, the actually measured time-dependent trend of the first parameter will also change linearly over time. Here, the proportionality factors reflecting the time-dependent correlation of the change can be the same or different in the actually measured time-dependent trend and the expected time-dependent trend. Depending on how these two proportionality factors differ from each other, the current wear state of the monitored component can be inferred.

[0090] In another scenario, although the actually measured time-dependent trend of the first parameter may initially change linearly, its subsequent course over time can change and no longer change linearly with time, but change, for example, sub-proportionally or supra-proportionally. The deviation that needs to be observed here between the actually measured time-dependent trend of the first parameter and the pre-determined expected linearly time-dependent trend of the first parameter enables inferences to be drawn about the current and / or future wear state.

[0091] According to one embodiment, the wear state can be determined based on the characteristic reversal (Umkehrung) of the actually measured time-dependent trend of the monitored first parameter compared to the hitherto time-dependent trend of the first parameter.

[0092] In other words, it can be observed that the monitored first parameter progresses in a certain direction over a certain period of time, i.e., follows a trend. From a certain moment on, the direction in which the property reflected by the first parameter changes can reverse, i.e., a trend reversal occurs. If such a trend reversal is identified by comparing the actual course of the first parameter over time with the expected course of the first parameter over time, this can contain information about the current and / or future wear state of the monitored component. In this case, the expected course of the first parameter over time can correspond to the hitherto actual course of the first parameter over time. In other words, if the actual course of the first parameter over time is significantly different over time from the time extrapolation of the previous actual course of the first parameter over time, such a trend reversal can be identified.

[0093] According to one embodiment, the wear state can be determined based on a sign change of the second time derivative of the actual course of the monitored first parameter over time compared to the second time derivative of the hitherto actual course of the first parameter over time.

[0094] In other words, it can be observed how the actual course of the monitored first parameter over time changes over time. Here, the change occurring over time can be represented by the first time derivative of the actual course of the first parameter over time. The change can follow a trend, i.e., for example, gradually become smaller, so that the physical property reflected by the first parameter seems to approach a saturation value. If this trend changes, this may mean that the change, which was originally becoming smaller over time for the first parameter, suddenly becomes larger again. This can generally be accompanied by a sign change of the second time derivative of the actual course of the monitored first parameter over time. Such a sudden change in the hitherto trend and the accompanying sign change can be an indicator of a certain wear state in the relevant component.

[0095] According to one embodiment in combination with a specific example, the wear state can be determined based on the case where the elastic modulus of a rope-like sling of a sling structure decreases with use after initially increasing.

[0096] In a specific example, the sling can be a rope with a large number of internal and external core wires. Generally, the internal core wires achieve a large part of the rope's load-bearing capacity and bear most of the mechanical stress within the rope during use. The external core wires surround and protect the internal core wires. Although the external core wires generally contribute to the rope's bending stiffness, the external core wires only bear a small part of the load-bearing capacity of the rope and thus also a small part of the mechanical stress. For solid steel ropes (within the typical elevator load range, the minimum rope breaking load is between 2% and 8.33%), the rope core (internal core wire) has a higher mechanical longitudinal stress than the external core wires. Due to the stranding structure, the stress level of the external core wires is much lower than that of the rope core.

[0097] Over time, especially the internal core wires may gradually increase the elasticity of the rope due to signs of fatigue, i.e., the elastic modulus of the rope decreases. The rope obviously becomes softer, so over time, the amount of readjustment when approaching the floor and the amount of horizontal adjustment when loading and unloading the elevator car increase.

[0098] From a certain point in time, due to more frequent and greater stretching of the rope, the internal core wires may be torn or broken. This means that the load-bearing capacity of the rope is no longer mainly borne by the internal core wires as before, but also increasingly by the external core wires. This causes a reversal in the trend of the active elastic modulus of the entire rope, i.e., after the elastic modulus of the rope initially continuously decreases, the elastic modulus of the rope may suddenly increase again. This trend reversal can be identified by the sign change of the second-order time derivative of the actual trend of the elastic modulus to be measured or a measurement parameter associated therewith over time. The trend reversal can indicate that the rope has or will have a certain wear state in the future. For example, due to the trend reversal, the following inference can be drawn: within the rope, the core wires can no longer withstand the mechanical stress usually absorbed there, so the rope should be discarded, i.e., replaced, in the near future.

[0099] According to one embodiment, a predetermined expected trend of change over time of a first parameter can be determined based on a large number of measured values determined in different elevator devices.

[0100] In other words, the actual time-varying trend of the first parameter can be compared with the expected time-varying trend of this parameter, and the expected time-varying trend is determined in advance in such a way that values corresponding to the first parameter or at least associated with a first numerical value have been obtained on a large number of elevator devices. Thus, for example, the actual time-varying trend of the first parameter detected on a defined suspension structure of an elevator device can be compared with the previously recorded actual time-varying trend (as observed in other elevator devices). Based on such a comparison, in particular based on the deviation between the actual time-varying trend of the first parameter observed in a specific elevator device and the actual time-varying trend previously observed in other elevator devices, the current or future wear state of the monitored components in the suspension structure of the specific elevator device can be inferred.

[0101] According to a second aspect of the invention, a monitoring device is introduced, which is configured to carry out an embodiment of the above method.

[0102] For this purpose, the monitoring device can have one or more sensors, by means of which the first parameter and / or the second parameter and / or other parameters can be measured. For example, the monitoring device can have sensors for measuring the length of the suspension, sensors for measuring the tensile properties of the suspension, sensors for measuring the radial dimensions of the suspension, sensors for measuring the optical properties of the suspension, sensors for measuring the magnetic properties of the suspension, sensors for measuring the electrical properties of the suspension, sensors for measuring the mechanical stress within the suspension, sensors for measuring the dimensions of the contact surface structure of the drive sheave, sensors for measuring the slip occurring between the contact surface of the suspension and the drive sheave, and / or sensors for measuring the force exerted by the suspension structure on the anchor. Such sensors can include, for example, optical sensors such as photodiodes or cameras, electrical sensors, mechanical sensors, magnetic sensors, etc.

[0103] The sensors can generate and forward measurement signals, in particular electrical measurement signals, based on the currently measured parameters. The monitoring device can have an evaluation device, in which the measurement signals are received and evaluated. The evaluation device can have a processor, by means of which the measurement signals or measurement data can be processed. In particular, the monitoring device can have a data memory, in which the measurement signals can be temporarily stored. Specifically, the monitoring device can be configured to record the measurement signals and ultimately monitor the actual time-varying trend of the parameters by means of temporary storage.

[0104] The monitoring device can be connected to the controller of the elevator equipment so as to be able to exchange data with the controller. In particular, information about the wear state determined in the monitoring device can be forwarded to the controller of the elevator equipment. Alternatively or additionally, the monitoring device of the elevator equipment can be connected to a control center, for example so as to be able to transmit information about the determined wear state to the control center. In addition, the monitoring device of the elevator equipment can be connected to the monitoring devices of other elevator equipment when necessary and can exchange data with the said monitoring devices.

[0105] The computer program product according to the third aspect of the present invention comprises software in the form of computer-readable instructions which cause a computer, which can be part of the above-mentioned monitoring device for example, to execute or control an embodiment of the method proposed herein. Here, the computer program product can be programmed in any computer language.

[0106] According to the fourth aspect of the present invention, the computer program product can be stored on a computer-readable medium. The computer-readable medium can be technically implemented in different ways. For example, the computer-readable medium can be a flash memory, a CD, a DVD or other portable, volatile or non-volatile memory. Alternatively, the computer-readable medium can be part of a network consisting of computers or servers, in particular part of the Internet or part of a data cloud (Cloud), from which the computer program product can be downloaded.

[0107] It should be noted that some feasible features and advantages of the present invention are introduced herein with reference to different embodiments, on the one hand the embodiments of the method introduced here and on the other hand the embodiments of the monitoring device for performing the said method. Those skilled in the art will recognize that these features can be combined, transferred, adjusted or interchanged in a suitable manner to achieve other embodiments of the present invention. Description of the Drawings

[0108] The embodiments of the present invention will be described below with reference to the drawings, where neither the drawings nor the description should be construed as limiting the present invention.

[0109] Figure 1 A monitoring device for determining the wear state of components of a suspension structure in an elevator equipment according to an embodiment of the present invention is shown.

[0110] The drawing is only schematic and not to scale. The same reference numerals denote the same features or features having the same effect. Detailed Embodiments

[0111] Figure 1 An elevator equipment 1 is shown, in which the wear state of components of a suspension structure 5 can be determined by means of a monitoring device 3.

[0112] The elevator installation 1 has an elevator car 7 and a counterweight 9, which can be moved vertically between different floors 13 in an elevator shaft 11. The elevator car 7 and the counterweight 9 can be held and moved with the aid of a suspension structure 5. For this purpose, the suspension structure 5 has a plurality of rope-like suspensions 15, such as ropes, belts or straps. The suspensions 15 can be driven by a drive sheave 17 of a drive machine 19. For this purpose, the drive sheave 17 can have a structure adapted to the geometry of the suspension 15 on the contact surface 21 against which the suspension 15 bears, for example in the form of grooves, recesses or the like. In the example shown, the suspension 15 is fixed to the top 25 of the elevator shaft 11 by means of an anchor 23. Starting from the top of the elevator shaft, the suspension 15 extends downwards to deflection rollers 27, 29 mounted on the elevator car 7 or the counterweight 9 and then extends upwards again to the drive sheave 17 of the drive machine 19. The operation of the drive machine 19 is controlled by an elevator controller 31. The elevator controller 31 can communicate with a monitoring device 3.

[0113] In the elevator installation 1, a large number of sensors or sensor elements are provided, by means of which the following parameters can be monitored, and inferences can be drawn from these parameters regarding the state or characteristics within the elevator installation 1, which states or characteristics are associated with or influence the wear state of the components of the suspension structure 5. These sensors or sensor elements can be connected to the monitoring device 3 by wire or are designed to be able to communicate wirelessly with the monitoring device 3 in order to be able to transmit measurement data or measurement signals reflecting the parameters measured by the sensors or sensor elements to the monitoring device 3.

[0114] For example, a length measuring sensor element 35 is provided at the lower end of the elevator shaft 11, near a buffer 33 adjoining the travel path of the counterweight 9. When the counterweight 9 is in its lowest possible position, i.e. when the elevator car 7 is arranged on the highest possible floor 13, the distance between the counterweight 9 and the buffer 33 can be determined by means of the length measuring sensor element 35. Indirectly, an inference can be drawn from the measurement of this distance regarding the current length of the suspension 15, which length can change over time, in particular due to material stretching.

[0115] The radial dimension of the suspension 15, i.e. for example the diameter of a load-bearing rope or the thickness of a load-bearing belt, can be measured by means of a sensor element specially adapted for this purpose. For example, a camera 37 can be used for this purpose, the field of view of which is directed at the suspension 15. If necessary, the camera 37 can also be used alternatively or in addition to detect optical properties of the suspension, such as changes in the surface texture on the suspension and / or changes in colour, reflectivity or the like.

[0116] In addition, a sensor device 39 for measuring the magnetic properties of the spreader 15 can be provided. With the aid of this sensor device 39, for example, the magnetic flux passing through one of the spreaders 15 can be measured.

[0117] Additionally or as a supplement, a sensor device 41 for measuring the electrical properties of the spreader 15 can be provided. This sensor device 39 can, for example, measure the current or resistance passing through one of the spreaders 15.

[0118] The anchoring member 23 can be designed as an intelligent fixing point and is configured to measure the mechanical stress on or in the spreader 15. For example, strain gauges can be provided in the anchoring member 23, which interact with the spreader 15 or its anchored end. If necessary, the anchoring member 23 can also be designed to measure the force exerted by the spreader on the anchoring member 23.

[0119] In addition, a sensor device 43 can be provided, by means of which the dimensions of the structure of the contact surface 21 of the drive wheel disk 17 can be monitored. For example, such a sensor device 43 can again be implemented using a camera or other optical sensors, but sensors operating in different ways can also be used.

[0120] In addition, the monitoring device 3 can obtain data and information from the elevator controller 31 and / or other sensors 45, by means of which the elevator controller and / or other sensors can, for example, determine the current position of the elevator car 7 in the elevator shaft 11. In combination with this data and information, other parameters associated with the wear of the components of the spreader structure 5 can be inferred.

[0121] For example, inferences about the tensile properties of the spreader 15 can be drawn based on how frequently and / or at what distance the elevator controller 31 performs height calibration when the elevator car 7 is stopped at the floor 13.

[0122] By comparing the controlled displacement distance obtained by the elevator controller 31 under the control of the drive machine 19 with the actual displacement distance of the elevator car 7 or the counterweight 9 (as can be detected, for example, by means of the signals of the sensor 45), slippage occurring between the spreader 15 and the contact surface 21 of the drive wheel disk 17 can also be inferred.

[0123] In addition, a temperature sensor 47, an air humidity sensor 49 and / or a barometric pressure sensor 51 can be provided in the elevator shaft in order to be able to measure the conditions present in the area of the spreader 15.

[0124] The monitoring device 3 is configured to perform the following method using the measurement data that can be provided by at least one of the above-mentioned sensors or sensor devices, by means of which information about the current and / or future wear state of the components of the spreader structure 5 can be determined.

[0125] To this end, the monitoring device 3 generally has a data processing device, such as a data processor and a data memory, in which measurement data can be stored and recalled at a later point in time, and the monitoring device has a data interface through which the monitoring device 3 can exchange data with various sensors and sensor elements, for example.

[0126] Within the scope of the method, for example, by collecting and tracking measurement data from one or more sensors and sensor elements, the actual trend of change of a first parameter is continuously monitored or at predetermined time intervals. Here, the first parameter is selected in such a way that the first parameter is associated with the wear state of at least one of the components of the spreader structure 5. Then, the actual trend of change of the first parameter monitored in this way over time is compared with the predetermined expected trend of change of the parameter over time, and then the wear state of the monitored component is determined based on the result of this comparison.

[0127] For example, based on the data provided by the length measuring sensor element 35, the current length of the spreader 15 can be determined as the first parameter. By accumulating data over a certain period of time, information about the actual trend of change of the parameter over time can thus be derived, that is, how the length of the spreader 15 changes over time can be derived.

[0128] Based on previously conducted experiments, simulations, and / or knowledge obtained from other elevator equipment, the expected trend of change over time can be predetermined, which represents how the length of the spreader generally changes over time. By comparing the actual trend of change over time of the length characteristic of the spreader 15 with the expected trend of change over time, a judgment about the current and / or future wear state of the spreader 15 can be determined.

[0129] For example, it can be found that the observed spreader 15 extends faster over time than is known from the spreaders used as references and has thus been anticipated. This information can be used to draw inferences about the ongoing wear state and / or, for example, the time point at which the spreader 15 will reach the allowable wear limit.

[0130] As a supplement to the monitoring of the first parameter, a second parameter is preferably also monitored. Similar to the first parameter, the second parameter can be associated with the wear state of the monitored component. However, it can be preferred that the second parameter even affects the wear state, that is, a judgment about how the wear state changes over time can be derived from the second parameter.

[0131] Many different combinations of the first and second parameters to be monitored are conceivable or advantageous. Here, for example, it can be advantageous to select the two parameters to be monitored in relation to each other. In particular, it can be advantageous for the manner of monitoring or evaluating the first parameter to be determined as a function of the selection of the second parameter and / or as a function of the actual course of the second parameter over time.

[0132] For example, the temperature present in the elevator shaft 11 or directly on the suspension gear 15 can be monitored as the second parameter, for example by means of a temperature sensor 47. Then, in the above example, the wear state of the suspension gear 15 can be determined based on a comparison of the actual course of the length of the suspension gear 15 and, additionally, based on the actual course of the measured temperature. Here, the fact can be used that the temperature present over a longer period of time has an influence on the wear occurring in the suspension gear 15, and the wear can in turn be reflected in the change in length of the suspension gear 15. In this case, based on the actual course of the temperature, the expected course of the change in length over time in the suspension gear 15 can be pre-determined.

[0133] In this case, based on a plurality of feasible pre-determined expected courses of the change in length over time, for the different temperatures present during the monitoring period, they are calculated, simulated, experimentally determined or observed on other devices. The expected course of the change in length over time can be used for comparison with the actual course of the change in length, and the expected course of the change in length over time is obtained corresponding to the actual course of the change over time of the temperature conditions.

[0134] In general, information about the current and / or future wear state of the components of the suspension gear structure 5 can be determined, in particular based on the identified deviation of the actual course of the monitored first parameter over time from the pre-determined expected course of the parameter, which is assumed to be linear, for example. A characteristic reversal of the actual course of the monitored parameter over time or a change in the sign of the second time derivative of the actual course of the monitored parameter over time can provide a good indication or a good data basis for determining the wear state of the monitored component.

[0135] In a special variant of the proposed method, the expected course of the first parameter over time can be pre-determined based on a large number of measured values obtained on various other elevator installations 53. For this purpose, the monitoring device 3 can communicate with a server 55, for example, which can receive such measured values from other elevator installations 53 and, if necessary, evaluate and / or temporarily store these measured values. The server 55 can be part of a data cloud, for example, and / or can be arranged in a control center that monitors a large number of elevator installations 53.

[0136] Finally, it should be noted that terms such as "comprising" and "including" do not exclude other elements or steps, and terms such as "a" or "one" do not exclude a plurality. In addition, it should be pointed out that features or steps introduced with reference to one of the above embodiments can also be used in combination with other features or steps of the other above embodiments. The reference signs in the claims should not be construed as restrictive.

Claims

1. A method for determining the wear state of components of a suspension structure (5) of an elevator installation (1), wherein, The method includes: Monitoring the actual trend of a first parameter varying over time, the trend being associated with the wear state of at least one monitored first component in a component; Comparing the monitored actual trend of the first parameter varying over time with a predetermined expected trend of the first parameter varying over time; Determining the wear state of the monitored first component based on the result of the comparison; Characterized in that The wear state is determined based on the following: after the elastic modulus of the rope-like sling (15) of the sling structure (5) has been continuously decreasing previously, the elastic modulus of the rope-like sling (15) begins to increase.

2. The method according to claim 1, wherein The sling structure at least includes the following components: At least one rope-like sling (15); A drive wheel disk (17) driven by a drive machine (19) for displacing the sling (15) that abuts against the contact surface (21) of the drive wheel disk (17); At least one anchoring member (23) of the sling (15), the at least one anchoring member being on an elevator car (7) to be displaced by the sling structure (5) and / or in an elevator shaft (11) accommodating the sling structure (5).

3. The method according to claim 1 or 2, further comprising the following steps: Monitoring the actual trend of the second parameter over time, the actual trend of the second parameter over time affecting and / or being associated with the wear state of at least one monitored first component in the component, wherein, The second parameter is different from the first parameter; Based on the result of the comparison between the monitored actual trend of the first parameter varying over time and the predetermined expected trend of the first parameter varying over time, and based on the monitored actual trend of the second parameter varying over time, determining the wear state of the monitored first component.

4. The method according to claim 3, wherein The first parameter and the second parameter are associated with the wear state of the monitored first component in different ways.

5. The method according to claim 3, wherein The first parameter and the second parameter are associated with the wear state of the monitored first component in the sling structure in an interacting manner.

6. The method according to claim 3, wherein Based on the measurement result of the monitored second parameter, selecting the predetermined expected trend of the first parameter varying over time from a plurality of feasible predetermined expected trends of the first parameter varying over time.

7. The method according to claim 3, wherein The second parameter to be monitored is selected from a group of parameters including: The temperature in the area of the sling structure (5); The air humidity in the area of the sling structure (5); and The air pressure in the area of the sling structure (5).

8. The method according to claim 3, wherein, The second parameter to be monitored represents the running frequency of the elevator car (7) moved by the sling structure (5).

9. The method according to claim 1 or 2, wherein, The wear state is determined based on the deviation between the monitored actual trend of the first parameter varying over time and the predetermined expected linear trend of the first parameter varying over time.

10. The method according to claim 1 or 2, wherein The wear state is determined based on the characteristic inversion of the monitored actual trend of the first parameter varying over time compared to the hitherto trend of the first parameter varying over time.

11. The method according to claim 1 or 2, wherein The wear state is determined based on the sign change of the second-order time derivative of the monitored actual trend of the first parameter varying over time compared to the second-order time derivative of the hitherto actual trend of the first parameter varying over time.

12. The method according to claim 1 or 2, wherein, The predetermined expected trend of the first parameter varying over time is predetermined based on a plurality of measured values determined on different elevator devices (1).

13. A monitoring device for determining the wear state of components of a suspension structure (5) of an elevator installation (1), wherein, The monitoring device (3) is configured to perform or control the method according to any one of the preceding claims.

14. A computer program product comprising computer-readable instructions which, when executed on a computer, cause the computer to perform or control the method according to any one of claims 1 to 12.

15. A computer-readable medium having stored thereon the computer program product according to claim 14.

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