Method for detecting safety performance of in-use elevator brake

Abstract

The invention discloses an in-use elevator brake safety performance detection method, relates to the technical field of special equipment elevator detection, and is used for solving the technical problems of related test methods and risk category research and judgment in brake evaluation in accordance with GB / T-42615 Safety Evaluation Standards for In-use Elevator. The in-use elevator brake safety performance detection method comprises the following steps of brake response time measurement, brake synchronism measurement and action voltage measurement of an in-use elevator brake. Wherein the measurement of the braking response time is divided into two working conditions, one working condition is that the elevator ascends to the upper part of the stroke without load to stop, and the other working condition is that the car is loaded with 1.25 times of rated load to downwards run to the lower part of the stroke to stop; it is suggested that no-load ascending braking is carried out firstly, and then a 1.25-time rated load descending braking test is carried out.

Description

Technical Field

[0001] The present invention relates to the technical field of special equipment elevator detection, and in particular to a method for detecting the safety performance of an in-use elevator brake. Background Art

[0002] Currently, according to GB / T 24478-2023, "Elevator Hoist," "brake response time" is defined as the time from when the brake power is removed until the braking torque reaches its rated value. Existing brake response time measurement methods are primarily performed on laboratory bench tests, such as the hoist inertia simulation test system. This method installs the hoist under test on a laboratory bench for testing, simulating the hoist's actual operating conditions and testing the hoist's dynamic performance during start-up, acceleration, deceleration, and stopping. The inertia simulation test system measures brake response time by driving the hoist at rated speed under the power source. The power to the brake is then removed, and a recorder is used to record the time difference between the hoist's brake electrical signal and the torque sensor's signal reaching the rated braking torque. While this measurement method offers high accuracy, it is not suitable for measuring the brake response time of hoist brakes in use.

[0003] According to GB / T 24478-2023, "Elevator Traction Machines," the "maximum release voltage of the brake electromagnet" is defined as the critical voltage at which the electromagnetic force of the brake electromagnet cannot maintain the engaged state. Existing devices for detecting the operating voltage of elevator block brake electromagnets typically remove the original input power supply of the block brake and connect an adjustable DC regulated power supply to the block brake electromagnet. This allows accurate detection of the minimum engagement voltage and maximum release voltage. After the detection is complete, the original input power supply can be quickly reconnected. However, the inventors of this application found that it has the following defects: (1) The reading of the brake action voltage is to gradually increase the input voltage of the brake, and the wheel is manually turned. When the traction wheel starts to rotate, the reading on the voltage-stabilized power supply is the lowest pull-in voltage. Similarly, the input voltage of the brake is slowly reduced. When the traction wheel goes from rotating to not rotating, the output of the voltage-stabilized power supply is the highest release voltage. However, it does not take into account that if the weight difference on both sides of the traction wheel is large, there may be a safety hazard caused by rapid slipping during the brake opening process; (2) It only considers the state where two sets of brakes are lifted or released at the same time, while the existing standards GB / T7588 and GB / T24478 require that the mechanical components of the brake should be installed in at least two sets. If only the state of being able to turn (or the state of not turning) is considered, the situation where the brake does not act synchronously will inevitably be ignored. Therefore, this method leads to unscientific measurement; (3) It only involves the measurement of the action voltage of the block brake, and does not involve the measurement of other brakes. Summary of the Invention

[0004] The present invention aims to provide a method for testing the safety performance of in-use elevator brakes, which can solve the technical problems of complying with the relevant test methods and risk classification assessment in brake evaluation in accordance with GB / T-42615 "Specification for Safety Evaluation of In-use Elevators". The method can directly output the risk assessment value and risk category of the brake-specific equipment based on the results, graphically output the test data, and scientifically output the test report. It can solve the technical problems of unscientific measurement of braking response time and inconvenience in installing torque sensors on elevator traction machine mechanisms. By establishing a dynamic model of elevator braking response time, it can construct the relationship between braking torque and acceleration and deceleration during braking. It can solve the technical problem of visual data measurement of elevator jams. By measuring the displacement of two sets of brakes (98% are two sets), it can effectively avoid the uncertainty caused by visual observation. It can solve the technical problems of universality, scientificity and calibration of the brake action voltage measurement of elevators in use, and use displacement sensors and adjustable DC power supply to measure the minimum pull-in voltage and maximum release voltage of the brake; It can detect the dynamic performance of elevator brakes in use, including the brake response time, the minimum pull-in voltage and maximum release voltage of the brake electromagnet, and the brake synchronization (i.e., the judgment of the jamming phenomenon).

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A method for detecting the safety performance of an elevator brake in use comprises the following steps: Braking response time measurement: After the elevator reaches the terminal, cut off the power supply and take safety precautions. Install the motion parameter acquisition sensor, brake displacement sensor, and voltage acquisition sensor in the machine room and operating space, and adjust the motion parameter acquisition sensor to be close to the traction sheave. Adjust the two sets of brake displacement sensors to face the moving block of the block brake. Turn on the test host and ensure that the test host and handheld terminal WiFi are connected. Reset the displacement sensor reading to zero, and the test host enters the test state. No-load upward working condition: The test host starts working before the elevator starts running from the bottom terminal. The voltage acquisition sensor measures the voltage of the brake, the motion parameter acquisition sensor acquires the motion parameters of the traction wheel, and the brake displacement sensor acquires the displacement change of the brake. When the elevator runs to the upper part of the stroke, the power supply of the elevator is manually cut off. The elevator starts to slow down and finally stops under the action of the brake. The voltage signal collected by the test host through the voltage acquisition sensor is processed by the AD conversion module of the test host. When the voltage changes from high level "1" to low level "0" after processing, it is the timing starting point t0 of the braking response time. The motion parameter acquisition sensor records the changes in speed and acceleration during the entire operation, and differentiates the collected speed Calculation, when the acceleration of the traction sheave is detected to be "zero" at time t1, the elevator braking torque is equal to the eccentric load torque, at this time the traction sheave speed reaches the maximum Vmax and the traction sheave acceleration is "zero", the time between t0 and t1 recorded by the measuring instrument is the braking response time; 1.25 times rated load downward braking condition: before the elevator starts running from the top terminal, the test host starts working. The voltage acquisition sensor measures the voltage of the brake, the motion parameter acquisition sensor acquires the motion parameters of the traction sheave, and the brake displacement sensor acquires the displacement change of the brake. When the elevator runs to the lower part of the stroke, the power supply of the elevator is manually cut off. The elevator starts to decelerate and finally stops under the action of the brake. The voltage signal collected by the test host through the voltage acquisition sensor is processed by the AD conversion module of the test host. The moment when the voltage changes from high level "1" to low level "0" after processing is the timing starting point t0 of the braking response time. The motion parameter acquisition sensor records the speed and deceleration changes during the entire operation period and performs differential operation on the collected speed. The moment when the acceleration of the traction sheave is detected to be "zero" is t1. The time between t0 and t1 recorded by the measuring instrument is the braking response time. Brake synchronicity measurement: The brake displacement sensor records the displacement changes of the two sets of brakes over time from the moment the elevator starts running to the moment the elevator comes to a complete stop. The time and displacement of the two sets of brakes are compared. The time difference between the displacement changes of the two sets of brakes is the synchronization time difference ∆t. In other words, one set of brakes is earlier or later than the other set by ∆t. At the same time, the motion parameter acquisition sensor records the motion status of the traction sheave. When the traction sheave begins to move, if the displacement of a set of brakes does not change significantly, it indicates that the brake set is in a dragging state. Measurement of the operating voltage of the elevator brake in use: Place the unloaded car at the middle or lower floor, and check the braking performance of each set of brakes separately before carrying out the action voltage and synchronization test. If the braking performance is abnormal, do not carry out the action voltage test. After the braking performance is normal, check the rated working voltage of the brake under test, turn off the main power switch, and disconnect the original input power of the brake, and make corresponding marks on the traction wire rope; The power supply of the unilateral brake is connected to the adjustable voltage-stabilized switching power supply for detection. At the same time, the other group or other groups of brakes are manually opened with a release wrench. The input voltage of the brake under test is slowly increased through the adjustable voltage-stabilized switching power supply, and the car is manually cranked. When the brake electromagnet changes from the released state to the state where the brake is closed and cannot maintain the released state, the electromagnet starts to attract / the brake starts to release / the empty elevator starts to move, the critical voltage U1 is the minimum attraction voltage of the brake electromagnet; With the voltage regulation of the adjustable voltage-stabilized switching power supply, the critical voltage U2 when the elevator car slides to a standstill when the brake electromagnet changes from the lifted state and the brake is released to the unable to maintain the attracted state, or when the traction machine turns from the dynamic state to the static state, is the maximum release voltage of the brake electromagnet; Test the lowest engagement voltage and highest release voltage of other brake groups. When testing other brake groups, the elevator car needs to be inspected and run to the traction wire rope mark position during the initial test to ensure that the weight on both sides is consistent when the elevator is sliding or turning, and record the displacement of the corresponding brake; If the elevator slips rapidly or encounters other emergency and dangerous situations, the emergency stop operating device of the adjustable voltage-stabilized switching power supply should be immediately cut off, the power input should be cut off, and the brake should be closed; the minimum pull-in voltage and maximum release voltage of each set of brakes should be measured and judged, and the minimum pull-in voltage and maximum release voltage of the brake electromagnet should be lower than 80% and 40% of the rated voltage respectively.

[0006] In actual application, the safety performance detection method of the elevator brake in use also includes the construction of a dynamic model of the braking response time: the brake release process is to disconnect the current, the electromagnetic force gradually weakens, and the combined force of the spring force and the electromagnetic force increases, pushing the armature to move so that the brake positively presses the traction sheave, and the traction sheave stops rotating, that is, the total time of the brake closing process includes the armature release response stage and the armature movement stage.

[0007] Among them, after the brake circuit is powered off, it is equivalent to a zero-input response circuit. The differential equation of the zero-input response circuit is: , inductor current , the inductor current does not disappear immediately, but gradually decreases; Electromagnetic force after power failure , where k is the electromagnetic force coefficient, which is determined by the number of coil turns, the cross-sectional area of the magnetic furnace, and the air gap; That is, the electromagnetic force Fx(t) gradually subsides. During this stage, the electromagnetic force is greater than or equal to the elastic force Fs(t) provided by the spring, until the moment the armature is ready to start moving, the electromagnetic force Fx(t) is equal to the elastic force Fs(t) of the spring.

[0008] Specifically, the armature movement stage is from the moment the spring starts to push the armature to move, until it fully presses on the traction sheave. During the armature movement stage, as the electromagnetic force fades and weakens, the elastic force Fs(t) provided by the spring becomes greater than the electromagnetic force Fx(t), and the spring pushes the armature to move until the brake shoe fully presses on the brake wheel. When the car is loaded with 125% of the rated load and moves downward at the rated speed, the drive main unit should be stopped by the brake alone; that is, when conducting the braking performance test, the car is loaded with 1.25 times the rated load, descends to the lower part of the stroke at the rated speed, and the power supply to the motor and the brake is cut off.

[0009] Furthermore, in the braking performance test, The static torque converted by the system to the brake, also called the eccentric load torque, Where is the rated load, in kg; is the reduction ratio, also known as the wire rope ratio; is the balance coefficient; g is the standard acceleration of gravity; is the diameter of the traction sheave, in m; is the mass difference between the wire rope and the compensation device, in kg; is the mechanical efficiency related to braking; is the dynamic torque, also called the inertia torque, Where is the total mass of the elevator system, in kg; is the equivalent diameter of the elevator transmission system, in m; is the angular velocity of the brake wheel / disc, in rad / s; The braking torque acting on the brake wheel is , ; Angular deceleration of the brake wheel / disc, ; Since the traction wheel and the brake wheel are coaxially connected and have the same angular deceleration, the deceleration of the traction wheel is .

[0010] Furthermore, within a certain period of time after the brake is powered off, including part of the armature release response phase and the armature movement phase, the braking torque is 0, according to the formula Analysis shows that the deceleration of the traction wheel It is a negative value, indicating that the speed of the traction sheave increases downward in this stage; When the deceleration of the traction sheave When it is 0, = , indicating that the braking torque is equal to the static torque / eccentric load torque at this time, and then as the braking torque increases, > , deceleration of the traction sheave A positive value indicates that under the action of braking torque and dynamic torque / eccentric load torque, the traction sheave is decelerating and the traction sheave speed begins to decrease.

[0011] Furthermore, the torque required for normal operation of the elevator is , , where is the total mechanical transmission efficiency of the elevator; when the turbine pair is used, is 0.5~0.55; using gearless traction machine, 0.75~0.8; The rated braking torque of the traction machine is at least 2.5 times the torque converted from the rated torque of the traction machine to the brake wheel / disc. , ; Rated braking torque of the elevator under normal circumstances > That is, during the braking process, after the brake reaches the rated braking torque, the traction sheave has begun to perform uniform deceleration motion. Therefore, the relationship between the traction sheave speed V and time t during the entire braking process is as follows: Point A is the moment when the power is cut off, at which time the traction sheave speed is Ve, and at Point B the brake pad begins to contact the brake wheel / disc, but at this time the braking torque is less than the eccentric load torque, and the brake wheel is still in accelerated downward motion. The time taken from A to B is t0, and at Point C the elevator braking torque is equal to the eccentric load torque. At this time, the traction sheave speed reaches the maximum Vmax and the traction sheave acceleration is 0. The time taken from A to C is t1, and then the braking torque becomes larger and larger due to the rapid dissipation of the electromagnetic force. The car begins to decelerate until it reaches Point D, and the braking torque at Point D reaches the rated braking torque. After that, the traction sheave enters uniform deceleration motion under the action of the rated braking torque until the traction sheave stops rotating. The time taken from Point A to Point D is t2.

[0012] Furthermore, by the formula It can be seen that the electromagnetic force is positively correlated with the square of the current. After the brake power is cut off, the inductor current Attenuation, the electromagnetic force decays faster than the inductive current decays, so when the braking torque is Increase to point D It is mainly the attenuation of the electromagnetic force that causes the increase in the resultant braking force. Since the electromagnetic force decays quickly, the time from point C to point D is short. Therefore, the time from the time the brake is powered off to the point where the traction wheel acceleration is zero, that is, the time from the time the traction wheel speed is Vmax, can be used as the braking response time to convert the measurement of the braking torque into the measurement of the motion parameters of the brake wheel or traction wheel.

[0013] In actual application, the test system consists of a test host, motion parameter acquisition sensors, brake displacement sensors, voltage acquisition sensors, and a handheld terminal; The test host is composed of a control system, a motion parameter signal module, a displacement signal module, a voltage acquisition module, an adjustable switching power supply module, a power management module, and a communication module.

[0014] Among them, the sensor fixing bracket is a magnetic base, which can be used to fix on the steel structure of the machine room or operating space.

[0015] Compared with the prior art, the method for detecting the safety performance of elevator brakes in use according to the present invention has the following advantages: 1. Accurately measure the dynamic parameters of elevator brakes in use, filling an industry gap: Traditional methods rely heavily on laboratory bench tests, making it difficult to accurately reflect the dynamic characteristics of elevator brakes in use. The method and device described in this application can evaluate the braking response time, operating status, operating voltage, and synchronization of elevator brakes in use. This effectively solves the problem of quantitatively analyzing the hidden dangers of brake release timeout or brake electromagnet moving iron core jamming in elevators in use, providing a scientific basis for safety assessments. 2. Meeting national standards and facilitating standardization of safety evaluation: The method and device mentioned in this application can be used as relevant test methods and risk category assessments in brake evaluation in GB / T-42615 "Specifications for Safety Evaluation of In-use Elevators". They can systematically evaluate key indicators such as brake response time, action voltage, and action consistency. They can be widely used in scenarios such as brake performance evaluation, accident investigation, repair and maintenance, and regular inspection of old elevator brakes. Their application will significantly improve the standardization and accuracy of elevator brake safety assessments and reduce the risk of safety accidents caused by brake failure. 3. Improve supervision efficiency and safeguard public safety: With the acceleration of urbanization, the number of elevators continues to grow. Brake failure has become one of the main causes of elevator safety accidents. In recent years, top-rushing accidents caused by brake failure have occurred frequently. The application of the methods and devices mentioned in this application will promote the transformation of elevator safety supervision from "post-event disposal" to "pre-event prevention", and help to achieve accurate inspection of safety hazards and risk warnings, which is of great significance to ensuring the safety of the public when riding elevators and promoting high-quality development of the elevator industry. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1A schematic diagram of a process for measuring the braking response time in a method for detecting the safety performance of an elevator brake provided by an embodiment of the present invention; Figure 2 A schematic diagram of a flow chart of measuring the operating voltage of an elevator brake in use in a method for detecting the safety performance of an elevator brake in use provided by an embodiment of the present invention; Figure 3 A schematic diagram of the brake force structure in the method for detecting the safety performance of an elevator brake in use provided by an embodiment of the present invention; Figure 4 A schematic diagram of an equivalent circuit after power is cut off in the brake circuit of an elevator brake safety performance detection method provided by an embodiment of the present invention; Figure 5 A schematic diagram of a simplified elevator system model during a brake test in a method for detecting the safety performance of an elevator brake provided by an embodiment of the present invention; Figure 6 A schematic diagram of a curve showing a change in traction sheave speed over time during a braking test in a method for detecting the safety performance of an elevator brake provided by an embodiment of the present invention; Figure 7 A schematic structural diagram of a test system in a method for detecting the safety performance of an in-use elevator brake provided by an embodiment of the present invention; Figure 8 A structural diagram of a test host of a test system in a method for detecting the safety performance of an elevator brake provided by an embodiment of the present invention.

[0017] Reference numerals: 1-Test host; 2-Motion parameter acquisition sensor; 3-Brake displacement sensor; 4-Voltage acquisition sensor; 5-Handheld terminal; 6 - elevator brake; 7 - elevator traction sheave; 8 - elevator guide sheave; 9 - elevator brake wheel; 10 - elevator wire rope; 11 - wiring terminals for the brake coil in the brake power circuit; 12 - elevator control cabinet; 101 - control system; 102 - motion parameter signal module; 103 - displacement signal module; 104 - voltage acquisition module; 105 - adjustable switching power supply module; 106 - power management module; 107 - communication module. DETAILED DESCRIPTION

[0018] For ease of understanding, the following detailed description of the method for detecting the safety performance of an elevator brake in use provided by an embodiment of the present invention is provided in conjunction with the accompanying drawings.

[0019] The embodiment of the present invention provides a method for detecting the safety performance of an elevator brake in use, such as Figure 1 and Figure 2 As shown, the following steps are included: Braking response time measurement: After the elevator reaches the terminal, cut off the power supply and take safety precautions. Install the motion parameter acquisition sensor, brake displacement sensor, and voltage acquisition sensor in the machine room and operating space, and adjust the motion parameter acquisition sensor to be close to the traction sheave. Adjust the two sets of brake displacement sensors to face the moving block of the block brake. Turn on the test host and ensure that the test host and handheld terminal WiFi are connected. Reset the displacement sensor reading to zero, and the test host enters the test state. No-load upward working condition: The test host starts working before the elevator starts running from the bottom terminal. The voltage acquisition sensor measures the voltage of the brake, the motion parameter acquisition sensor acquires the motion parameters of the traction wheel, and the brake displacement sensor acquires the displacement change of the brake. When the elevator runs to the upper part of the stroke, the power supply of the elevator is manually cut off. The elevator starts to slow down and finally stops under the action of the brake. The voltage signal collected by the test host through the voltage acquisition sensor is processed by the AD conversion module of the test host. When the voltage changes from high level "1" to low level "0" after processing, it is the timing starting point t0 of the braking response time. The motion parameter acquisition sensor records the changes in speed and acceleration during the entire operation, and differentiates the collected speed Calculation, when the acceleration of the traction sheave is detected to be "zero" at time t1, the elevator braking torque is equal to the eccentric load torque, at this time the traction sheave speed reaches the maximum Vmax and the traction sheave acceleration is "zero", the time between t0 and t1 recorded by the measuring instrument is the braking response time; 1.25 times rated load downward braking condition: before the elevator starts running from the top terminal, the test host starts working. The voltage acquisition sensor measures the voltage of the brake, the motion parameter acquisition sensor acquires the motion parameters of the traction sheave, and the brake displacement sensor acquires the displacement change of the brake. When the elevator runs to the lower part of the stroke, the power supply of the elevator is manually cut off. The elevator starts to decelerate and finally stops under the action of the brake. The voltage signal collected by the test host through the voltage acquisition sensor is processed by the AD conversion module of the test host. The moment when the voltage changes from high level "1" to low level "0" after processing is the timing starting point t0 of the braking response time. The motion parameter acquisition sensor records the speed and deceleration changes during the entire operation period and performs differential operation on the collected speed. The moment when the acceleration of the traction sheave is detected to be "zero" is t1. The time between t0 and t1 recorded by the measuring instrument is the braking response time. Brake synchronicity measurement: The brake displacement sensor records the displacement changes of the two sets of brakes over time from the moment the elevator starts running to the moment the elevator comes to a complete stop. The time and displacement of the two sets of brakes are compared. The time difference between the displacement changes of the two sets of brakes is the synchronization time difference ∆t. In other words, one set of brakes is earlier or later than the other set by ∆t. At the same time, the motion parameter acquisition sensor records the motion status of the traction sheave. When the traction sheave begins to move, if the displacement of a set of brakes does not change significantly, it indicates that the brake set is in a dragging state. Measurement of the operating voltage of the elevator brake in use: Place the unloaded car at the middle or lower floor, and check the braking performance of each set of brakes separately before carrying out the action voltage and synchronization test. If the braking performance is abnormal, do not carry out the action voltage test. After the braking performance is normal, check the rated working voltage of the brake under test, turn off the main power switch, and disconnect the original input power of the brake, and make corresponding marks on the traction wire rope; The power supply of the unilateral brake is connected to the adjustable voltage-stabilized switching power supply for detection. At the same time, the other group or other groups of brakes are manually opened with a release wrench. The input voltage of the brake under test is slowly increased through the adjustable voltage-stabilized switching power supply, and the car is manually cranked. When the brake electromagnet changes from the released state to the state where the brake is closed and cannot maintain the released state, the electromagnet starts to attract / the brake starts to release / the empty elevator starts to move, the critical voltage U1 is the minimum attraction voltage of the brake electromagnet; With the voltage regulation of the adjustable voltage-stabilized switching power supply, the critical voltage U2 when the elevator car slides to a standstill when the brake electromagnet changes from the lifted state and the brake is released to the unable to maintain the attracted state, or when the traction machine turns from the dynamic state to the static state, is the maximum release voltage of the brake electromagnet; Test the lowest engagement voltage and highest release voltage of other brake groups. When testing other brake groups, the elevator car needs to be inspected and run to the traction wire rope mark position during the initial test to ensure that the weight on both sides is consistent when the elevator is sliding or turning, and record the displacement of the corresponding brake; If the elevator experiences rapid slippage or other emergency and dangerous situations, the emergency stop operating device of the adjustable voltage-stabilized switching power supply should be immediately disconnected, the power input should be cut off, and the brake should be closed; the minimum pull-in voltage and maximum release voltage of each set of brakes should be measured and judged, and the minimum pull-in voltage and maximum release voltage of the brake electromagnet should be lower than 80% and 40% of the rated voltage respectively; After the above measurements are completed, the test data and charts related to each sub-project can be viewed on the handheld terminal, and the system can output the test report of the entire brake project.

[0020] Compared with the prior art, the method for detecting the safety performance of elevator brakes in use according to the embodiment of the present invention has the following advantages: 1. Accurately measure the dynamic parameters of elevator brakes in use, filling an industry gap: Traditional methods rely heavily on laboratory bench tests, making it difficult to accurately reflect the dynamic characteristics of elevator brakes in use. The method and device described in this application can evaluate the braking response time, operating status, operating voltage, and synchronization of elevator brakes in use. This effectively solves the problem of quantitatively analyzing the hidden dangers of brake release timeout or brake electromagnet moving iron core jamming in elevators in use, providing a scientific basis for safety assessments. 2. Meeting national standards and facilitating standardization of safety evaluation: The method and device mentioned in this application can be used as relevant test methods and risk category assessments in brake evaluation in GB / T-42615 "Specifications for Safety Evaluation of In-use Elevators". They can systematically evaluate key indicators such as brake response time, action voltage, and action consistency. They can be widely used in scenarios such as brake performance evaluation, accident investigation, repair and maintenance, and regular inspection of old elevator brakes. Their application will significantly improve the standardization and accuracy of elevator brake safety assessments and reduce the risk of safety accidents caused by brake failure. 3. Improve supervision efficiency and safeguard public safety: With the acceleration of urbanization, the number of elevators continues to grow. Brake failure has become one of the main causes of elevator safety accidents. In recent years, top-rushing accidents caused by brake failure have occurred frequently. The application of the methods and devices mentioned in this application will promote the transformation of elevator safety supervision from "post-event disposal" to "pre-event prevention", and help to achieve accurate inspection of safety hazards and risk warnings, which is of great significance to ensuring the safety of the public when riding elevators and promoting high-quality development of the elevator industry.

[0021] It should be noted that the braking response time is measured under two conditions: one is when the elevator is unloaded and stops at the upper end of its travel; the other is when the elevator is loaded with 1.25 times the rated load and stops at the lower end of its travel. It is recommended to first conduct an unloaded upward braking test and then conduct a downward braking test with 1.25 times the rated load if no abnormalities are found. The maximum release voltage and the minimum engagement voltage of the brake electromagnet are respectively the state where the electromagnetic force of the brake electromagnet cannot maintain the engaged state and the state where the brake starts to engage; since the brake power supply is a DC power supply and the load is an inductive load, the power output value of the elevator brake circuit loop is fixed, so an external adjustable voltage-stabilized switching power supply needs to be connected. In this application, the DC source input is 220V (AC), the output is adjustable from 0V to 150V (DC), the output power is 2kW, the step value is 0.2V, and it is equipped with an emergency stop device, which can cut off the output power in an emergency.

[0022] In practical application, the method for detecting the safety performance of elevator brakes in use provided by the embodiment of the present invention may also include constructing a dynamic model of the braking response time: Figure 3As shown in the figure, the brake release process is to disconnect the current, the electromagnetic force gradually weakens, and the combined force of the spring force and the electromagnetic force increases, pushing the armature to move so that the brake presses the traction sheave positively, and the traction sheave stops rotating. That is, the total time of the brake closing process includes the armature release response stage and the armature movement stage.

[0023] Among them, Figure 4 As shown, after the brake circuit is powered off, it is equivalent to a zero-input response circuit. The differential equation of the zero-input response circuit is: , inductor current , the inductor current does not disappear immediately, but gradually decreases; Electromagnetic force after power failure , where k is the electromagnetic force coefficient, which is determined by the number of coil turns, the cross-sectional area of the magnetic furnace, and the air gap; That is, the electromagnetic force Fx(t) gradually subsides. During this stage, the electromagnetic force is greater than or equal to the elastic force Fs(t) provided by the spring, until the moment the armature is ready to start moving, the electromagnetic force Fx(t) is equal to the elastic force Fs(t) of the spring.

[0024] Specifically, the armature movement stage is from the moment the spring starts to push the armature to move, until it fully presses on the traction sheave. During the armature movement stage, as the electromagnetic force fades and weakens, the elastic force Fs(t) provided by the spring becomes greater than the electromagnetic force Fx(t), and the spring pushes the armature to move until the brake shoe fully presses on the brake wheel. When the car is loaded with 125% of the rated load and moves downward at the rated speed, the drive main unit should be stopped by the brake alone; that is, when conducting the braking performance test, the car is loaded with 1.25 times the rated load and moves downward at the rated speed to the lower part of the stroke, and the power supply to the motor and the brake is cut off. Figure 5 shown.

[0025] Furthermore, in the braking performance test, The static torque converted by the system to the brake, also called the eccentric load torque, Where is the rated load, in kg; is the reduction ratio, also known as the wire rope ratio; is the balance coefficient; g is the standard acceleration of gravity; is the diameter of the traction sheave, in m; is the mass difference between the wire rope and the compensation device, in kg; is the mechanical efficiency related to braking; is the dynamic torque, also called the inertia torque, Where is the total mass of the elevator system, in kg; is the equivalent diameter of the elevator transmission system, in m; is the angular velocity of the brake wheel / disc, in rad / s; The braking torque acting on the brake wheel is , ; Angular deceleration of the brake wheel / disc, ; Since the traction wheel and the brake wheel are coaxially connected and have the same angular deceleration, the deceleration of the traction wheel is .

[0026] Furthermore, within a certain period of time after the brake is powered off, including part of the armature release response phase and the armature movement phase, the braking torque is 0, according to the formula Analysis shows that the deceleration of the traction wheel It is a negative value, indicating that the speed of the traction sheave increases downward in this stage; When the deceleration of the traction sheave When it is 0, = , indicating that the braking torque is equal to the static torque / eccentric load torque at this time, and then as the braking torque increases, > , deceleration of the traction sheave A positive value indicates that under the action of braking torque and dynamic torque / eccentric load torque, the traction sheave is decelerating and the traction sheave speed begins to decrease.

[0027] Furthermore, the torque required for normal operation of the elevator is , , where is the total mechanical transmission efficiency of the elevator; when the turbine pair is used, is 0.5~0.55; using gearless traction machine, 0.75~0.8; The rated braking torque of the traction machine is at least 2.5 times the torque converted from the rated torque of the traction machine to the brake wheel / disc. , ; Rated braking torque of the elevator under normal circumstances > , that is, during the braking process, after the brake reaches the rated braking torque, the traction sheave has begun to do uniform deceleration motion. Therefore, the relationship between the traction sheave speed V and time t during the entire braking process is as follows: Figure 6As shown: Point A is the moment when the power is cut off. At this time, the traction sheave speed is Ve. At point B, the brake pad begins to contact the brake wheel / disc, but at this time the braking torque is less than the eccentric load torque. The brake wheel is still in accelerated downward motion. The time taken from A to B is t0. At point C, the elevator braking torque is equal to the eccentric load torque. At this time, the traction sheave speed reaches the maximum Vmax and the traction sheave acceleration is 0. The time taken from A to C is t1. Subsequently, the braking torque becomes larger and larger due to the rapid dissipation of the electromagnetic force. The car begins to decelerate until it reaches point D. The braking torque at point D reaches the rated braking torque. After that, the traction sheave enters a uniform deceleration motion under the action of the rated braking torque until the traction sheave stops rotating. The time taken from point A to D is t2.

[0028] Furthermore, by the formula It can be seen that the electromagnetic force is positively correlated with the square of the current. After the brake power is cut off, the inductor current Attenuation, the electromagnetic force decays faster than the inductive current decays, so when the braking torque is Increase to point D It is mainly the attenuation of the electromagnetic force that causes the increase in the resultant braking force. Since the electromagnetic force decays quickly, the time from point C to point D is short. Therefore, the time from the time the brake is powered off to the point where the traction wheel acceleration is zero, that is, the time from the time the traction wheel speed is Vmax, can be used as the braking response time to convert the measurement of the braking torque into the measurement of the motion parameters of the brake wheel or traction wheel.

[0029] In actual application, such as Figure 7 As shown, the test system can be composed of a test host 1, a motion parameter acquisition sensor 2, a brake displacement sensor 3, a voltage acquisition sensor 4, and a handheld terminal 5; like Figure 8 As shown, the above-mentioned test host 1 can be composed of a control system 101, a motion parameter signal module 102, a displacement signal module 103, a voltage acquisition module 104, an adjustable switching power supply module 105, a power management module 106, and a communication module 107.

[0030] The sensor fixing bracket may preferably be a magnetic base, so that it can be used to fix on the steel structure of the machine room or operating space.

[0031] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for detecting the safety performance of an elevator brake in use, characterized in that it comprises the following steps: Braking response time measurement: After the elevator reaches the terminal, cut off the power supply and take safety precautions. Install the motion parameter acquisition sensor, brake displacement sensor, and voltage acquisition sensor in the machine room and operating space, and adjust the motion parameter acquisition sensor to be close to the traction sheave. Adjust the two sets of brake displacement sensors to face the moving block of the block brake. Turn on the test host and ensure that the test host and handheld terminal WiFi are connected. Reset the displacement sensor reading to zero, and the test host enters the test state. No-load upward working condition: The test host starts working before the elevator starts running from the bottom terminal. The voltage acquisition sensor measures the voltage of the brake, the motion parameter acquisition sensor acquires the motion parameters of the traction wheel, and the brake displacement sensor acquires the displacement change of the brake. When the elevator runs to the upper part of the stroke, the power supply of the elevator is manually cut off. The elevator starts to slow down and finally stops under the action of the brake. The voltage signal collected by the test host through the voltage acquisition sensor is processed by the AD conversion module of the test host. When the voltage changes from high level "1" to low level "0" after processing, it is the timing starting point t0 of the braking response time. The motion parameter acquisition sensor records the changes in speed and acceleration during the entire operation, and differentiates the collected speed Calculation, when the acceleration of the traction sheave is detected to be "zero" at time t1, the elevator braking torque is equal to the eccentric load torque, at this time the traction sheave speed reaches the maximum Vmax and the traction sheave acceleration is "zero", the time between t0 and t1 recorded by the measuring instrument is the braking response time; 1.25 times rated load downward braking condition: Before the elevator starts running from the top terminal, the test host begins operation. The voltage acquisition sensor measures the brake voltage, the motion parameter acquisition sensor collects the motion parameters of the traction sheave, and the brake displacement sensor collects the displacement change of the brake. When the elevator reaches the bottom of its travel, the power supply is manually cut off. The elevator begins to decelerate and eventually stops under the action of the brake. The voltage signal collected by the voltage acquisition sensor of the test host is processed by the test host's AD conversion module. The moment when the processed voltage changes from high level "1" to low level "0" is the starting point t0 of the braking response time. The motion parameter acquisition sensor records the speed and deceleration changes during the entire operation and performs a differential operation on the collected speed. The moment when the traction sheave acceleration is detected to be "zero" is t1. The time between t0 and t1 recorded by the measuring instrument is the braking response time. Brake synchronicity measurement: The brake displacement sensor records the displacement changes of the two sets of brakes over time from the moment the elevator starts running to the moment the elevator comes to a complete stop. The time and displacement of the two sets of brakes are compared. The time difference between the displacement changes of the two sets of brakes is the synchronization time difference ∆t. In other words, one set of brakes is earlier or later than the other set by ∆t. At the same time, the motion parameter acquisition sensor records the motion status of the traction sheave. When the traction sheave begins to move, if the displacement of a set of brakes does not change significantly, it indicates that the brake set is in a dragging state. Measurement of the operating voltage of the elevator brake in use: Place the unloaded car at the middle or lower floor, and check the braking performance of each set of brakes separately before carrying out the action voltage and synchronization test. If the braking performance is abnormal, do not carry out the action voltage test. After the braking performance is normal, check the rated working voltage of the brake under test, turn off the main power switch, and disconnect the original input power of the brake, and make corresponding marks on the traction wire rope; The power supply of the unilateral brake is connected to the adjustable voltage-stabilized switching power supply for detection. At the same time, the other group or other groups of brakes are manually opened with a release wrench. The input voltage of the brake under test is slowly increased through the adjustable voltage-stabilized switching power supply, and the car is manually cranked. When the brake electromagnet changes from the released state to the state where the brake is closed and cannot maintain the released state, the electromagnet starts to attract / the brake starts to release / the empty elevator starts to move, the critical voltage U1 is the minimum attraction voltage of the brake electromagnet; With the voltage regulation of the adjustable voltage-stabilized switching power supply, the critical voltage U2 when the elevator car slides to a standstill when the brake electromagnet changes from the lifted state and the brake is released to the unable to maintain the attracted state, or when the traction machine turns from the dynamic state to the static state, is the maximum release voltage of the brake electromagnet; Test the lowest engagement voltage and highest release voltage of other brake groups. When testing other brake groups, the elevator car needs to be inspected and run to the traction wire rope mark position during the initial test to ensure that the weight on both sides is consistent when the elevator is sliding or turning, and record the displacement of the corresponding brake; If the elevator slips rapidly or encounters other emergency and dangerous situations, the emergency stop operating device of the adjustable voltage-stabilized switching power supply should be immediately cut off, the power input should be cut off, and the brake should be closed; the minimum pull-in voltage and maximum release voltage of each set of brakes should be measured and judged, and the minimum pull-in voltage and maximum release voltage of the brake electromagnet should be lower than 80% and 40% of the rated voltage respectively.

2. The method for detecting the safety performance of an elevator brake in use according to claim 1, characterized in that: It also includes the construction of a dynamic model of the braking response time: the brake release process is to disconnect the current, the electromagnetic force gradually weakens, the combined force of the spring force and the electromagnetic force increases, pushing the armature to move so that the brake presses the traction wheel positively, and the traction wheel stops rotating. That is, the total time of the brake closing process includes the armature release response stage and the armature movement stage.

3. The method for detecting the safety performance of an elevator brake in use according to claim 2, wherein: After the brake circuit is powered off, it is equivalent to a zero-input response circuit. The differential equation of the zero-input response circuit is: , inductor current , the inductor current does not disappear immediately, but gradually decreases; Electromagnetic force after power failure , where k is the electromagnetic force coefficient, which is determined by the number of coil turns, the cross-sectional area of the magnetic furnace, and the air gap; That is, the electromagnetic force Fx(t) gradually subsides. During this stage, the electromagnetic force is greater than or equal to the elastic force Fs(t) provided by the spring, until the moment the armature is ready to start moving, the electromagnetic force Fx(t) is equal to the elastic force Fs(t) of the spring.

4. The method for detecting the safety performance of an elevator brake in use according to claim 2 or 3, characterized in that: The armature movement stage is from the moment the spring starts to push the armature to move, until it fully presses on the traction sheave. During the armature movement stage, as the electromagnetic force fades and weakens, the elastic force Fs(t) provided by the spring becomes greater than the electromagnetic force Fx(t), and the spring pushes the armature to move until the brake shoe fully presses on the brake wheel. When the car is loaded with 125% of the rated load and moves downward at the rated speed, the drive main unit should be stopped by the brake alone; that is, when conducting the braking performance test, the car is loaded with 1.25 times the rated load, descends to the lower part of the stroke at the rated speed, and the power supply to the motor and the brake is cut off.

5. The method for detecting the safety performance of an elevator brake in use according to claim 4, characterized in that: During the braking performance test, The static torque converted from the system to the brake, also called the eccentric load torque, Where is the rated load, in kg; is the reduction ratio, also known as the wire rope ratio; is the balance coefficient; g is the standard acceleration of gravity; is the diameter of the traction sheave, in m; The mass difference between the wire rope and the compensation device, in kg; is the mechanical efficiency related to braking; is the dynamic torque, also called the inertia torque, Where is the total mass of the elevator system, in kg; is the equivalent diameter of the elevator transmission system, in m; is the angular velocity of the brake wheel / disc, in rad / s; The braking torque acting on the brake wheel is , ; Angular deceleration of the brake wheel / disc, ; Since the traction wheel and the brake wheel are coaxially connected and have the same angular deceleration, the deceleration of the traction wheel is .

6. The method for detecting the safety performance of an elevator brake in use according to claim 5, characterized in that: Within a certain period of time after the brake is powered off, including part of the armature release response phase and the armature movement phase, the braking torque is 0, according to the formula Analysis shows that the deceleration of the traction wheel It is a negative value, indicating that the speed of the traction sheave increases downward in this stage; When the deceleration of the traction sheave When it is 0, = , indicating that the braking torque is equal to the static torque / eccentric load torque at this time, and then as the braking torque increases, > , deceleration of the traction sheave A positive value indicates that under the action of braking torque and dynamic torque / eccentric load torque, the traction sheave is decelerating and the traction sheave speed begins to decrease.

7. The method for detecting the safety performance of an elevator brake in use according to claim 6, characterized in that: The torque required for the normal operation of the elevator is , , where is the total mechanical transmission efficiency of the elevator; when the turbine pair is used, 0.5~0.55; Using gearless traction machine, 0.75~0.8; The rated braking torque of the traction machine is at least 2.5 times the torque converted from the rated torque of the traction machine to the brake wheel / disc. , ; Rated braking torque of the elevator under normal circumstances > That is, during the braking process, after the brake reaches the rated braking torque, the traction sheave has begun to perform uniform deceleration motion. Therefore, the relationship between the traction sheave speed V and time t during the entire braking process is as follows: Point A is the moment when the power is cut off, at which time the traction sheave speed is Ve, and at Point B the brake pad begins to contact the brake wheel / disc, but at this time the braking torque is less than the eccentric load torque, and the brake wheel is still in accelerated downward motion. The time taken from A to B is t0, and at Point C the elevator braking torque is equal to the eccentric load torque. At this time, the traction sheave speed reaches the maximum Vmax and the traction sheave acceleration is 0. The time taken from A to C is t1, and then the braking torque becomes larger and larger due to the rapid dissipation of the electromagnetic force. The car begins to decelerate until it reaches Point D, and the braking torque at Point D reaches the rated braking torque. After that, the traction sheave enters uniform deceleration motion under the action of the rated braking torque until the traction sheave stops rotating. The time taken from Point A to Point D is t2.

8. The method for detecting the safety performance of an elevator brake in use according to claim 7, characterized in that: By It can be seen that the electromagnetic force is positively correlated with the square of the current. After the brake power is cut off, the inductor current Attenuation, the electromagnetic force decays faster than the inductive current decays, so when the braking torque is Increase to point D It is mainly the attenuation of the electromagnetic force that causes the increase in the resultant braking force. Since the electromagnetic force decays quickly, the time from point C to point D is short. Therefore, the time from the time the brake is powered off to the point where the traction wheel acceleration is zero, that is, the time from the time the traction wheel speed is Vmax, can be used as the braking response time to convert the measurement of the braking torque into the measurement of the motion parameters of the brake wheel or traction wheel.

9. The method for detecting the safety performance of an elevator brake in use according to claim 1, characterized in that: The test system consists of a test host, motion parameter acquisition sensors, brake displacement sensors, voltage acquisition sensors, and a handheld terminal; The test host is composed of a control system, a motion parameter signal module, a displacement signal module, a voltage acquisition module, an adjustable switching power supply module, a power management module, and a communication module.

10. The method for detecting the safety performance of an elevator brake in use according to claim 1 or 9, characterized in that: The sensor fixing bracket is a magnetic base that can be used to fix it on the steel structure of the machine room or operating space.

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