System and method for detecting brake fault

Abstract

An elevator system for elevator brake fault detection, comprising: an elevator comprising a car (2); a lifting machine (3) for driving the car in the elevator shaft (1) between the landing floors (11); and at least one mechanical brake (34) for braking the movement of the car and / or keeping the car stationary; and the elevator system further comprises at least one sensor (20) operable to obtain movement data of the car (2). The elevator system is configured to detect a change in a condition of the at least one mechanical brake (34) based on the movement data obtained by the at least one sensor (20) during normal operation. A method for elevator brake fault detection in an elevator system.

Description

Technical Field

[0001] The present invention relates to elevator brake fault detection.The elevator is preferably an elevator for transporting passengers and / or freight. Background Art

[0002] Elevators have a mechanical hoisting machinery brake as a safety device to apply a braking force to the traction sheave or rotating shaft of the elevator hoisting machine to brake the movement of the hoisting machine and, therefore, the movement of the elevator car. There are usually two separate brakes. For example, they can be shoe brakes or disc brakes and have brake pads adapted to engage against a braking surface in the rotating part of the elevator hoisting machine. In older elevators there may be only one such hoisting machinery brake.

[0003] The lifting mechanical brake has a stationary frame and an armature which is movably supported on the frame, for example by means of a sliding shaft extending through the frame. The frame may contain an electromagnet to generate an attractive force between the frame and the armature. In addition, an energy reservoir, such as a compression spring, may be arranged between the frame and the armature. A brake pad may be attached to the armature. The brake is opened by supplying an electric current to the electromagnet and is closed by means of the energy reservoir when the current supply is interrupted. Instead of an electromagnet, other kinds of actuators, such as a hydraulic actuator, may also be used.

[0004] The brakes must be sized to stop the elevator car in the elevator shaft and keep it stationary. In addition, they can be used in rescue situations and emergency braking situations to stop the elevator car in the event of an operating fault, such as an overspeed situation of the elevator car. In addition, they can be used to protect elevator passengers from unexpected car movements at the landings and to provide a safe operating environment for maintenance personnel in the elevator shaft. Therefore, it is necessary to ensure that the brakes operate correctly. For example, if the brakes are not opened correctly, the brake pads may drag on the traction sheave during elevator operation, resulting in, for example, accelerated wear and may further lead to a degradation of the braking force. If the brakes are not closed correctly, i.e., in the event that they do not start braking as expected, a potentially dangerous situation may occur.

[0005] Particularly in new elevators, the correct opening of the brakes can be monitored with a sensor (e.g. a brake switch) which changes its state when the brakes are opened. However, brake switches can be expensive, unreliable, and sometimes difficult to fit into a brake monitoring system.

[0006] Sometimes the brake switch does not notice that the brake is not fully on or off. Brake failure may also develop gradually as friction in the brake shaft increases slowly over a longer period of time. This can mean that brake failure may continue for some time before being noticed.

[0007] Therefore, there is a need for a solution to detect failure of a hoisting machinery brake in a reliable manner. Summary of the invention

[0008] The object of the invention is to introduce an elevator system and a method for elevator brake fault detection.The invention provides solutions to the problems associated with the faults of the elevator hoisting machinery brake described above and below.

[0009] An elevator system for elevator brake fault detection according to the invention is defined in the independent claim 1 .

[0010] In general, the present invention relates to an elevator system comprising an elevator car, a hoisting machine for driving the car in an elevator shaft between landing floors, a sensor operable to obtain movement data (preferably acceleration data) of the car, and at least one machinery brake, in particular a hoisting machinery brake, for braking the movement of the car and / or holding the car stationary. The elevator system further comprises at least one sensor operable to obtain movement data of the car. The elevator system is configured to detect a change in the condition of the at least one machinery brake based on the movement data of the car obtained by the at least one sensor during normal operation.

[0011] The method for elevator brake fault detection according to the invention is defined in claim 11 .

[0012] The present disclosure introduces a solution for condition monitoring of hoisting machinery brakes. This solution is compatible with new elevators and can also be easily retrofitted to old elevators for OEM elevators and third-party elevators obtained under maintenance contracts.

[0013] The advantage of this solution is that it can remotely detect this very serious safety failure of the elevator before it occurs. Therefore, elevator safety can be increased at minimal additional cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The present invention will be described in more detail below by means of preferred embodiments with reference to the accompanying drawings, in which:

[0015] Figure 1 shows a side view of an elevator system having a brake for braking the movement of a car and / or holding the car stationary,

[0016] Figure 2 The steps of the elevator brake fault detection method according to the embodiment are shown.

[0017] Figure 3 Example graphs showing start kick and acceleration peak;

[0018] Figure 4 and Figure 5 An example of oscillations in the acceleration of the car is shown. DETAILED DESCRIPTION

[0019] In the present drawings, the elevator is not shown to scale, but the drawings are schematic, showing the basic structure and operation of the preferred embodiment. In this case, the components indicated by the reference numerals in the drawings correspond to the components indicated by the reference numerals in this specification.

[0020] Figure 1 An elevator system with a car 2, a shaft 1, a hoisting machine 3, suspension ropes 4 and a counterweight 5 is shown. A separate or integrated car frame 6 (also called a sling) may surround the car. The hoisting machine 3 may be positioned in the shaft 1. The hoisting machine may include a drive 31, an electric motor 32 and a traction sheave 33.

[0021] The system comprises at least one mechanical brake 34 for braking the movement of the car and / or holding the car stationary.

[0022] according to Figure 1 In the illustrated embodiment, the at least one machinery brake 34 comprises a lifting machinery brake 34 positioned in connection with the lifting machinery 3 .

[0023] The at least one machinery brake for braking the movement of the car and / or holding the car stationary does not necessarily have to be in the lifting machine 3 .

[0024] According to an embodiment, the at least one machinery brake for braking the movement of the car and / or holding the car stationary comprises at least one machinery brake located in the car 2, preferably acting on the guide rails of the car.

[0025] According to an embodiment, at least one machinery brake 34 for braking the movement of the car and / or keeping the car stationary comprises at least one hoisting machinery brake 34 positioned in connection with the hoisting machinery 3 and at least one machinery brake located in the car 2 .

[0026] The hoisting machinery 3 can move the car up and down in the shaft. The machinery brake 34 can stop the rotation of the traction sheave 33, thereby stopping the movement of the elevator car 2.

[0027] exist Figure 1 In the embodiment, the car 2 is connected to the counterweight 5 via the traction sheave 33 and one or more diverting pulleys (not shown) by ropes 4. The car and the counterweight are suspended by one or more ropes 4, which are guided on the traction sheave 33 for moving the car 2 vertically in the shaft 1.

[0028] exist Figure 1In the embodiment of the present invention, the car 2 is further supported by guide members 7 at guide rails 8 extending in the vertical direction in the shaft. The guide rails can be attached to a side wall structure 10 in the shaft by means of fastening brackets 9. The guide members 7 ensure the vertical movement of the car 2 when the car moves upwards and downwards in the shaft 1. The counterweight 5 can be supported in a corresponding manner on the guide rails attached to the wall structure of the shaft.

[0029] The elevator system further comprises a sensor 20 operable to obtain movement data of the car 2 .

[0030] The elevator system is configured to detect a change in the condition of the at least one machinery brake 34 based on the movement data of the car obtained by the sensor 20 during normal operation.

[0031] The term "normal operation" refers to elevator service, ie the transfer of elevator passengers and / or cargo between landing floors using an elevator car such that the movement of the car follows a desired motion profile.

[0032] According to an embodiment, the elevator system includes a condition-based monitoring system configured to detect changes in the condition of at least one machinery brake 34 for braking movement of the car and / or holding the car stationary based on movement data of the car obtained by the sensor 20 during normal operation.

[0033] According to an embodiment, a sensor 20 operable to obtain movement data of the car 2 is attached to the car 2. Preferably, the sensor 20 is mounted to the elevator car roof 2.1.

[0034] According to an embodiment, the elevator system comprises a processing device 30 with an acceleration sensor 20. Preferably, the processing device 30 is attached to the elevator car, preferably mounted to the elevator car roof 2.1. The processing device 30 is configured to collect and process data of the elevator operation, in particular car movement data.

[0035] According to an embodiment, the elevator system comprises an external cloud computing network 40, a wireless communication system 50 (such as a data link) and a wireless transceiver 51. The processing device 30 is configured to send data of elevator operation (particularly car movement data) to the external cloud computing network 40 via the wireless data link 50 (e.g. a cellular network). For this purpose, the device 30 comprises a wireless transceiver 51.

[0036] According to an embodiment, the wireless data link 50 is configured as a communication system for sending messages to a predetermined receiver, which may be located outside the installation site of the elevator. For example, the communication system may be a wireless communication system 50, such as a mobile communication system or a cellular network.

[0037] According to an embodiment, the movement data of the car 2 obtained by the sensor 20 is sent from the processing device 30 to a remote monitoring center 60, which monitors the operation of multiple elevators, for example. The monitoring center 60 may include a server or utilize a cloud service to store incoming messages, so that maintenance personnel can utilize a portable terminal 70 to, for example, check the status of the monitored elevator equipment. Alternatively or additionally, for example, the movement data may be directly sent to at least one terminal 70 of the maintenance personnel.

[0038] Figure 2 An example flow chart of a method for elevator brake fault detection is shown. The figure sequentially depicts the steps of an embodiment for condition monitoring of a hoisting machinery brake.

[0039] It has been found that elevator data after starting (in other words, after acceleration) can reveal anomalies in the brake function, such as the brakes not fully opening as commanded.

[0040] It has been found that, for the most part, elevator brake failures do not occur suddenly, but rather the friction in the mechanical elements of the elevator brake (such as the brake shaft or brake sleeve) increases slightly over a longer period of time - during brake opening and closing events, i.e., when the elevator starts and stops. Furthermore, the failure mode must evolve over a longer period of time, and therefore the data after startup reveals anomalies in the brake function.

[0041] By sensor 20 ( Figure 2 A) in the car movement data obtained ( Figure 2 B), in particular the change in acceleration data is used to detect brake failure, as described in this specification. According to an embodiment, the car movement data ( Figure 2 E).

[0042] The processing device 30 forming the analysis unit obtains or collects car movement data with the help of movement data sensors 20 (in particular acceleration sensors) during predetermined acceleration and deceleration phases at the beginning and end of the elevator operation, that is, when the car 2 leaves the departure floor 11 and when it arrives at the destination floor 11.

[0043] According to an embodiment, the car movement data is processed to find at least one of: start kick, acceleration peak, stop accuracy, and oscillations that may be periodic. In other words, the movement data is processed to find deviations from the expected car movement operation and indicate a deteriorated condition of the brakes ( Figure 2 The analysis can be performed in an external cloud computing network 40 or, for example, in a local control unit or edge computing unit located in the elevator venue.

[0044] According to an embodiment, the car movement data is processed to find the starting kick value ( Figure 2 The start kick is the maximum peak-to-peak value in the filtered acceleration signal. This signal is a short period centered on the start of movement of the car 2, preferably a 3 second period. Brake problems can be discovered by monitoring and detecting the increase in the start kick value over time.

[0045] According to an embodiment, the car movement data is processed to find the acceleration peak value ( Figure 2 H in.

[0046] Figure 3 Examples of starting kick values ​​obtained during an acceleration phase of car 2 (shown in the lower graph) and acceleration peak values ​​obtained during a later acceleration phase of car 2 (shown in the upper graph) as a function of time in an elevator system are shown.

[0047] The time periods of the condition monitoring of the elevator brake are shown on the horizontal axis within three 24-hour periods (Day I, Day II and Day III). The vertical axis represents the acceleration of the elevator car 2 in m / s 2 .

[0048] In the first two 24-hour monitoring periods I and II, when the elevator was mainly used between 3 hours and 19 hours, the start-up recoil value formed below 0.1m / s 2 On the third day III, the start-up recoil value also includes a value higher than 0.4m / s 2 Up to 1.2m / s 2 A significant travel group of increased start kick values ​​indicates a deteriorated condition of the brakes.

[0049] In addition, the acceleration peaks formed in the first two monitoring cycles I and II were mainly at 0.1 m / s 2 and 0.3m / s 2 On the third day III, while registering increasingly increasing values ​​of start-up recoil, the acceleration peaks also include values ​​with a value higher than 0.3 m / s 2 Up to 0.6m / s 2 A significant set of travel with increased acceleration peaks indicates a deteriorated condition of the brakes.

[0050] It is worth noting that the increased start-up kickback values ​​and therefore the brake sticking do not occur on all trips. Therefore, it is also unlikely to occur multiple times when maintenance personnel visit the elevator. Therefore, the mobile data-based condition monitoring method was found to be superior to visible inspections because it allows long-term comparison of elevator performance and data changes.

[0051] According to an embodiment, the car movement data are processed to find changes in the stopping accuracy of the elevator car 2 when approaching a landing floor 11 in the shaft 1 ( Figure 2 J in.

[0052] According to an embodiment, the car movement data is processed to calculate the oscillation of the acceleration of the car 2 ( Figure 2 The variable acceleration peak value is calculated as the maximum distance from the filtered acceleration signal to the actual acceleration signal. In other words, it describes the maximum so-called "vibration" of the elevator during the acceleration phase of car 2. When the value of the acceleration peak data grows and decreases over a period of time, brake problems can be monitored and detected as oscillations in this acceleration peak data, which may indicate the presence of wear in the mechanical elements of the elevator brake (such as the brake shaft or brake sleeve).

[0053] Figure 4 An example of oscillations in the acceleration of car 2 is shown. A detrended oscillatory signal d is constructed from a filtered actual oscillatory acceleration signal b obtained in an acceleration period of car 2. Reference symbol c shows the RMS value of the filtered signal b as a smooth curve. The detrended oscillatory signal d shows how signals b and c compare to each other.

[0054] Figure 5 It is shown how a detrended oscillatory signal g is constructed from a filtered actual oscillatory acceleration signal e obtained in an acceleration period of the car 2, wherein oscillations originating from a defective brake can be identified. Reference symbol f shows the RMS value of the filtered signal e as a smooth curve. The detrended oscillatory signal g shows how the signals e and f compare to each other.

[0055] According to an embodiment, when an indication of a degraded state of the brakes is obtained, a maintenance visit to the elevator site is scheduled to inspect and repair the brakes if necessary.

[0056] Because elevator brakes are critical to safe operation, it may be necessary to generate warnings and / or interrupt elevator service until brake inspection and repair work has been performed. According to an embodiment, if an indication of a degraded condition of the brakes is obtained (brake failure), a warning ( Figure 2 L), preferably communicated to the person responsible for the elevator condition, such as maintenance personnel.

[0057] According to an embodiment, the above described solution may also be applied to elevators without direct acceleration measurement, since the acceleration and preferably the signal calculated therefrom may be calculated from the measured speed / position.

[0058] According to an embodiment, the elevator system is configured to: determine, based on movement data obtained during normal operation, unexpected elevator car movement components, such as unexpected changes in stopping accuracy and / or starting kick and / or oscillation components and / or peak values; and detect a change in the state of the at least one machinery brake based on the movement components.

[0059] According to an embodiment, the data processing may include applying statistical methods and / or artificial intelligence.

[0060] Therefore, the elevator system and the elevator brake failure detection method can be implemented in an elevator system including a sensing device capable of detecting the moving speed / position of the car.

[0061] The use of the invention is not limited to the embodiments disclosed in the drawings. The invention can be used for any type of elevator, for example an elevator with or without a machine room, an elevator with or without a counterweight. The counterweight can be positioned on either side wall or on both sides or on the rear wall of the elevator shaft. The drive, motor, traction sheave and mechanical brake can be positioned in the machine room or somewhere in the elevator shaft. The elevator car guide rails can be positioned on opposite side walls of the shaft or on the rear wall of the shaft.

[0062] It is obvious to a person skilled in the art that, as technology advances, the inventive concept can be implemented in various ways.The invention and its embodiments are not limited to the examples described above but may vary within the scope of the claims.

Claims

1. An elevator system for elevator brake fault detection, comprising: An elevator, comprising a car (2); a hoisting machine (3) for driving the car in the elevator shaft (1) between landing floors (11); and at least one mechanical brake (34) for braking the movement of the car and / or keeping the car stationary; and the elevator system further comprises at least one sensor (20) operable to obtain movement data of the car (2); It is characterized in that The elevator system is configured to detect a change in a condition of the at least one machinery brake (34) based on movement data obtained by the at least one sensor (20) during normal operation.

2. The elevator system of claim 1, wherein the movement data obtained by the at least one sensor (20) includes car acceleration data.

3. An elevator system according to claim 1 or 2, wherein the at least one sensor (20) comprises an acceleration sensor or a sensing device capable of detecting the moving speed / position of the car.

4. Elevator system according to any of claims 1 to 3, wherein the at least one sensor is attached to the car (2), preferably to the car roof (2.1).

5. The elevator system according to any one of claims 1 to 4, wherein the at least one machinery brake comprises at least one hoisting machinery brake (34) comprised by the hoisting machinery (3) and / or the at least one machinery brake is located in the car (2).

6. The elevator system according to any one of claims 1 to 5, comprising a processing device (30) having the at least one sensor (20), the processing device being configured to collect and process movement data of the car obtained by the at least one sensor.

7. An elevator system according to any one of the preceding claims, wherein the system is configured to: determining from movement data obtained during normal operation undesirable elevator car movement components, such as undesirable changes in stopping accuracy and / or start kick and / or oscillatory components and / or peaks; and A change in a condition of the at least one machinery brake is detected based on the movement component.

8. The elevator system according to claim 6 comprises an external cloud computing network (40), a wireless data link (50) and a wireless transceiver (51), for transmitting the movement data of the car (2) obtained by the at least one sensor (20) from the processing device (30) to the external cloud computing network (40).

9. Elevator system according to any one of claims 1 to 8, wherein the hoisting machine (3) comprises a motor (32), a traction sheave (33) and at least one hoisting machine brake (34).

10. The elevator system according to any one of claims 1 to 9, wherein the elevator system comprises: one or more suspension ropes (4); and a counterweight (5); The car and the counterweight are suspended by the one or more ropes (4) which are guided on a traction sheave (33) for vertically moving the car (2) in the elevator shaft (1).

11. A method for elevator brake fault detection in an elevator system, the elevator system comprising: An elevator comprising a car (2); a hoisting machine (3) for driving the car in the elevator shaft (1) between landing floors (11); and at least one mechanical brake (34) for braking the movement of the car and / or holding the car stationary; wherein the method comprises operating at least one sensor (20) included by the elevator system to obtain movement data of the car (2) during normal operation; Characterized in that the method comprises: A change in the condition of the at least one machinery brake (34) is detected based on movement data obtained by the at least one sensor (20) during normal operation.

12. The method according to claim 11, wherein the method comprises obtaining car acceleration data by means of the at least one sensor (20), the at least one sensor (20) being preferably an acceleration sensor or a sensing device capable of detecting the speed / position of car movement.

13. Method according to claim 11 or 12, wherein the method comprises attaching the at least one sensor to the car (2), preferably to the car roof (2.1).

14. Method according to any one of claims 11 to 13, wherein the at least one machinery brake comprises at least one lifting machinery brake (34) comprised by the lifting machinery (3) and / or the at least one machinery brake is located in the car (2).

15. The method according to any one of claims 11 to 14, wherein: The method comprises obtaining movement data of the car (2) during predetermined acceleration and deceleration phases at the beginning and end of an elevator run.

16. A method according to any one of claims 11 to 15, wherein the method comprises processing car movement data to find performance characteristics that deviate from expected car movement operation and are indicative of a deterioration condition of the at least one machinery brake (34).

17. A method according to claim 16, wherein the method comprises processing the car movement data to find a start kick value which is increased during an acceleration phase of the car (2).

18. A method according to claim 16, wherein the method comprises processing the car movement data to find acceleration peaks which increase during later acceleration phases of the car (2).

19. The method according to claim 16, wherein: The method comprises processing the car movement data to find changes in the stopping accuracy of the elevator car (2) as the elevator car (2) approaches a landing floor (11) in the shaft (1).

20. The method of claim 16, wherein the method comprises processing the car movement data to find oscillations in the acceleration of the car (2).

21. The method according to any one of claims 11 to 20, wherein: The method comprises generating a warning if an indication of a degraded state of the brake is obtained.

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