Elevator brake spring length monitoring device and brake failure diagnosis method

Abstract

The application relates to the technical field of elevator brake fault diagnosis, in particular to an elevator brake spring length monitoring device and a brake fault diagnosis method, which comprises a mounting rod fixed at a left end of a fixed end face, wherein the right end of the mounting rod penetrates a brake arm; a spring is sleeved on the mounting rod, the left end of the spring is fixed on the fixed end face, and the right end of the spring is fixed on the brake arm; a capacitor inner electrode is fixed between the spring and the mounting rod on the right side of the fixed end face, a capacitor outer electrode is fixed between the spring and the capacitor inner electrode on the left side of the brake arm, and the capacitor inner electrode and the capacitor outer electrode partially overlap, so that the capacitor inner electrode and the capacitor outer electrode form a capacitor. The actual length of the spring in the braking and brake releasing states can be measured, the brake force of the elevator and the brake releasing force of the electromagnet are calculated, and the brake fault can be diagnosed.

Description

Technical Field

[0001] The present invention relates to the technical field of elevator brake fault diagnosis, in particular to an elevator brake spring length monitoring device and a brake fault diagnosis method. Background Art

[0002] In recent years, with the rapid increase in residential and commercial office buildings, the use of elevators has also grown rapidly. The brake in the elevator traction system is one of the most critical safety devices in the elevator. During elevator operation, the brake is the only device that can provide leveling braking, emergency braking, and even partial upward overspeed braking. Its reliability is crucial to the safety of passengers and property.

[0003] With the development of society, people's demand for safety is becoming increasingly stringent. Traditional elevator brake detection methods are no longer able to meet these demands. Traditional methods rely primarily on manual inspections and regular maintenance to ensure safe elevator operation. This consumes significant manpower and material resources and fails to provide real-time monitoring and early warning of elevator brake status. Manual inspections are subject to subjective judgment and errors, making the accuracy and reliability of monitoring results unreliable and prone to missed detections or misjudgments.

[0004] An elevator brake contains a coil spring. When braking is required, the friction plate on the brake arm is pressed against the brake wheel via the spring, providing braking torque. When the elevator car is in motion, the brake arm, under the action of the electromagnet's push rod, overcomes the spring's thrust, freeing the friction plate from the brake wheel. Therefore, the spring must provide sufficient pressure on the brake arm during braking, while the electromagnet must generate sufficient thrust to compress the spring during release. The initial free length and stiffness coefficient of an elevator's brake spring are both fixed and known. Therefore, by measuring the actual length of the spring in both the braking and release states, the braking force and the electromagnet's release force can be calculated, respectively. These are crucial parameters for proper elevator operation. If the spring's actual length falls below a certain threshold, a brake failure is considered. Measuring the actual spring length depends solely on the relative distance between the two spring ends and is independent of the absolute position of the fixed end. Measuring the spring length should not affect the spring's operation or alter its existing structure. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides an elevator brake spring length monitoring device and a brake fault diagnosis method, which can measure the actual length of the spring in the braking and release states, thereby calculating the elevator's braking force and the electromagnet release force, and then diagnosing the brake fault.

[0006] The present invention is implemented by the following technical solution: an elevator brake spring length monitoring device includes a mounting rod with its left end fixed on a fixed end surface, and the right end of the mounting rod penetrates a movable end surface; the spring is sleeved on the mounting rod, the left end of the spring is fixed on the fixed end surface, and the right end is fixed on the movable end surface; the right side of the fixed end surface is located between the spring and the mounting rod, and an inner capacitor electrode is fixed thereon; the left side of the movable end surface is located between the inner capacitor electrode and the spring, and an outer capacitor electrode is fixed thereon, and the inner capacitor electrode and the outer capacitor electrode partially overlap, so that the inner capacitor electrode and the outer capacitor electrode form a capacitor.

[0007] Preferably, the movable end face is a brake arm, a plunger-type electromagnet is provided on the upper right side of the brake arm, and a brake wheel is provided on the lower right side; a brake shoe for clamping the brake wheel is fixed to the lower end of the right side of the brake arm; the plunger-type electromagnet includes a shell, a coil is fixed in the shell, an iron core is provided in the coil, and a channel for the iron core to pass through is opened on the shell.

[0008] Preferably, it also includes a capacitor bridge, a signal amplification circuit, an AD conversion circuit, and a digital processor; the inner capacitor electrode and the outer capacitor electrode are electrically connected to the capacitor bridge respectively, the capacitor bridge is electrically connected to the input end of the signal amplification circuit, the output end of the signal amplification circuit is electrically connected to the input end of the AD conversion circuit, and the output end of the AD conversion circuit is electrically connected to the digital processor.

[0009] Braking fault diagnosis method:

[0010] Step S1, determining the elastic coefficient K of the spring;

[0011] Step S2: Establish the relationship between spring compression and capacitance.

[0012] The capacitance is

[0013] D is the radius of the outer electrode of the capacitor, d is the radius of the inner electrode of the capacitor, ΔL is the overlapping length between the inner electrode and the outer electrode of the capacitor, and ε0 is the dielectric constant;

[0014] ΔL depends on the compression of the spring. When the spring is at its original length and not compressed, it is ΔL0. When the traction machine brake is in the engaged state, the spring length is ΔL1. When the traction machine brake is in the released state, the spring length is ΔL2.

[0015] Step S3, calculating the brake force and the electromagnetic thrust when the brake is released;

[0016] The brake force is F1=B1K(ΔL1-ΔL0);

[0017] When the brake is released, the electromagnetic thrust is F2=B2K(ΔL2-ΔL0);

[0018] For a given elevator, B1 and B2 are constants, determined by the structural dimensions of the brake arm itself;

[0019] When F1 <F 10 When F2 <F 20 When the elevator release force is insufficient, F 10 、F 20 They are the set lower limit of the brake force and the lower limit of the release force respectively.

[0020] Beneficial effects of the present invention:

[0021] (1) The present invention can timely detect changes in the brake spring length by real-time monitoring of the capacitor capacity, thereby providing early warning of possible faults, providing maintenance personnel with more timely intervention opportunities, and reducing the possibility of accidents.

[0022] (2) The present invention adopts capacitance measurement technology, which can realize accurate monitoring of spring length. Compared with traditional measurement methods, it reduces the interference of environmental factors on measurement data and improves the credibility and reliability of monitoring results.

[0023] The present invention can measure the actual length of the spring in the braking and release states, thereby calculating the braking force of the elevator and the release force of the electromagnet, and further being able to diagnose braking faults. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a structural diagram of the first embodiment of the present invention.

[0025] Figure 2 yes Figure 1 Internal structure diagram.

[0026] Figure 3 It is a schematic diagram of the inner and outer electrodes of a capacitor.

[0027] Figure 4 It is a structural diagram of the second embodiment of the present invention.

[0028] Figure 5 It is the principle block diagram of the capacitor bridge, signal amplification circuit, AD conversion circuit, and digital processor. DETAILED DESCRIPTION

[0029] The present invention will be further described below with reference to the accompanying drawings.

[0030] like Figures 1 to 3The present invention provides an elevator brake spring length monitoring device, comprising a mounting rod 2 whose left end is fixed to a fixed end surface 1, and the right end of the mounting rod 2 penetrates a movable end surface 6; the mounting rod 2 is sleeved with the spring 5, the left end of the spring 5 is fixed to the fixed end surface 1, and the right end is fixed to the movable end surface 6; the right side of the fixed end surface 1 is located between the spring 5 and the mounting rod 2 and is fixed with an inner capacitor electrode 3; the inner capacitor electrode 3 is cylindrical, sleeved on the outside of the pull rod, and insulated and fixed to the fixed end surface 1; the left side of the movable end surface 6 is located between the inner capacitor electrode 3 and the spring 5 and is fixed with an outer capacitor electrode 4, the outer capacitor electrode 4 is cylindrical, sleeved on the outside of the pull rod, and insulated and fixed to the movable end surface 6; and the inner capacitor electrode 3 and the outer capacitor electrode 4 partially overlap, so that the inner capacitor electrode 3 and the outer capacitor electrode 4 form a capacitor; the size of the capacitor capacity is proportional to the compression deformation of the spring 5.

[0031] When the position of the movable end face 6 changes, the length of the spring 5 changes, and the overlapping length of the capacitor inner electrode 3 and the capacitor outer electrode 4 also changes. The capacitance of the capacitor also changes accordingly, and its size is related to the compression of the spring 5. Therefore, the deformation of the spring 5 can be calculated by measuring the capacitance of the capacitor.

[0032] The present invention also provides a brake fault diagnosis method, which is as follows:

[0033] Step S1, determining the elastic coefficient K of the spring 5;

[0034] Step S2: Establish the relationship between the compression amount of the spring 5 and the capacitance.

[0035] The capacitance is

[0036] D is the radius of the capacitor outer electrode 4, d is the radius of the capacitor inner electrode 3, ΔL is the overlapping length between the capacitor inner electrode 3 and the capacitor outer electrode 4, and ε0 is the dielectric constant;

[0037] ΔL depends on the compression amount of spring 5. When spring 5 is at its original length and not compressed, it is ΔL0. When the traction machine brake is in the engaged state, the length of spring 5 is ΔL1. When the traction machine brake is in the released state, the length of spring 5 is ΔL2.

[0038] Step S3, calculating the brake force and the electromagnetic thrust when the brake is released;

[0039] The brake force is F1=B1K(ΔL1-ΔL0);

[0040] When the brake is released, the electromagnetic thrust is F2=B2K(ΔL2-ΔL0);

[0041] For a given elevator, B1 and B2 are both constants, determined by the structural dimensions of the brake arm 12 itself;

[0042] When F1 <F 10 When F2 <F 20 When the elevator release force is insufficient, F 10 、F 20 They are the set lower limit of the brake force and the lower limit of the release force respectively.

[0043] like Figure 4 In one embodiment of the present invention, the movable end surface 6 is a brake arm 12, a plunger-type electromagnet is provided on the upper right side of the brake arm 12, and a brake wheel 11 is provided on the lower right side; a brake shoe 10 for clamping the brake wheel 11 is fixed to the lower end of the right side of the brake arm 12; the plunger-type electromagnet includes a shell 7, a coil 8 is fixed in the shell 7, an iron core 9 is provided in the coil 8, and a channel for the iron core 9 to pass through is opened on the shell 7.

[0044] When the brake is engaged, coil 8 is de-energized. The force of spring 5 presses brake arm 12 toward brake wheel 11, placing wheel 11 in direct contact with the friction lining of brake shoe 10. The braking torque is provided by the friction between brake shoe 10 and brake wheel 11. When the brake is released, coil 8 is energized, and the electromagnetic force acting on iron core 9 moves leftward, overcoming the force of spring 5 and pushing brake arm 12 away from brake wheel 11, releasing the brake wheel 11. Because the amount of spring 5 compression differs between the engaged and released states, the capacitance of the capacitor is used to calculate the amount of spring 5 compression, and thus the spring force, the brake force, and the electromagnetic thrust during release. The formula for calculating the spring force is K(ΔL1-ΔL0).

[0045] like Figure 5 In one embodiment of the present invention, a capacitance bridge 21, a signal amplifying circuit 22, an AD conversion circuit 23, and a digital processor 24 are further included for measuring capacitance, thereby monitoring the length of the spring 5. The inner capacitor electrode 3 and the outer capacitor electrode 4 are electrically connected to the capacitance bridge 21, respectively. The capacitance bridge 21 is electrically connected to the input end of the signal amplifying circuit 22, the output end of the signal amplifying circuit 22 is electrically connected to the input end of the AD conversion circuit 23, and the output end of the AD conversion circuit 23 is electrically connected to the digital processor 24.

[0046] The capacitance value to be measured is converted into a voltage signal through the capacitance bridge 21 (usually the voltage signal is relatively small), and the voltage signal is amplified by the signal amplifier circuit 22. The amplified voltage signal is input into the AD conversion circuit 23, and the voltage signal is converted into a digital signal and sent to the digital processor 24.

[0047] In one embodiment of the present invention, the capacitance measurement value from the A / D conversion circuit 23 is received by the digital processor 24 and processed and analyzed. The monitored spring 5 length data can be stored to analyze and evaluate the brake status. An alarm can also be installed to issue an alarm signal to notify the operator if the spring 5 length exceeds a preset range.

[0048] The above description is only a preferred embodiment of the present invention and should not be understood as limiting the present application. All equivalent changes and modifications made within the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A brake fault diagnosis method, characterized in that: Diagnosis is performed using an elevator brake spring length monitoring device, which includes a mounting rod with a left end fixed to a fixed end surface, and a right end of the mounting rod penetrating a movable end surface; a spring is sleeved on the mounting rod, with a left end of the spring fixed to the fixed end surface and a right end fixed to the movable end surface; an inner capacitor electrode is fixed to the right side of the fixed end surface between the spring and the mounting rod, and an outer capacitor electrode is fixed to the left side of the movable end surface between the inner capacitor electrode and the spring, with the inner capacitor electrode and the outer capacitor electrode partially overlapping to facilitate formation of a capacitor by the inner capacitor electrode and the outer capacitor electrode; Diagnosis is done as follows: Step S1, determining the elastic coefficient K of the spring; Step S2: Establish the relationship between spring compression and capacitance. The capacitance is D is the radius of the outer electrode of the capacitor, d is the radius of the inner electrode of the capacitor, ΔL is the overlapping length between the inner electrode and the outer electrode of the capacitor, and ε0 is the dielectric constant; ΔL depends on the compression of the spring. When the spring is at its original length and not compressed, it is ΔL0. When the traction machine brake is in the engaged state, the spring length is ΔL1. When the traction machine brake is in the released state, the spring length is ΔL2. Step S3, calculating the brake force and the electromagnetic thrust when the brake is released; The brake force is F1=B1K(ΔL1-ΔL0); When the brake is released, the electromagnetic thrust is F2=B2K(ΔL2-ΔL0); For a given elevator, B1 and B2 are constants, determined by the structural dimensions of the brake arm itself; When F1 <F 10 When F2 <F 20 When the elevator release force is insufficient, F 10 、F 20 They are the set lower limit of the brake force and the lower limit of the release force respectively.

2. The brake fault diagnosis method according to claim 1, characterized in that: The movable end face is a brake arm, a plunger-type electromagnet is provided on the upper right side of the brake arm, and a brake wheel is provided on the lower right side; a brake shoe for clamping the brake wheel is fixed at the lower end of the right side face of the brake arm; the plunger-type electromagnet includes a shell, a coil is fixed in the shell, an iron core is provided in the coil, and a channel for the iron core to pass through is opened on the shell.

3. The brake fault diagnosis method according to claim 1, characterized in that: It also includes a capacitor bridge, a signal amplification circuit, an AD conversion circuit, and a digital processor; the inner capacitor electrode and the outer capacitor electrode are electrically connected to the capacitor bridge respectively, the capacitor bridge is electrically connected to the input end of the signal amplification circuit, the output end of the signal amplification circuit is electrically connected to the input end of the AD conversion circuit, and the output end of the AD conversion circuit is electrically connected to the digital processor.

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