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The noise generated in this paper is mainly caused by both mechanical and electrical reasons. For the treatment of noise and vibration, the traditional treatment methods and methods belong to a kind of passive governance, that is, measures are taken to improve after the problem is discovered. This paper proposes the idea of ​​active management, in order to provide various links for Elevator design, manufacturing, installation and so on. reference. Analysis of elevator noise and vibration problems Mechanical problems 1. Installation of load-bearing elevators requires load-bearing devices with high strength and rigidity, otherwise vibrations and noise are likely to occur. The main defects of the load-bearing device are: 1 the rigidity of the load-bearing beam is not enough; 2 the appropriate damping device is needed between the Traction Machine and the load-bearing beam, and there are many damping devices in many elevators that often have the hardness and quantity of rubber materials. Unreasonable or uneven force.
2. Suspension device car and balance weight are all installed by suspension. In the actual installation process, the stiffness of the rope head vibration isolation device is too large or too small, and the center deviation of the car center and the traction rope is too large. The guide shoe is unevenly stressed to generate vibration. The tension of each wire rope is uneven and the swing is too large. Different wire rope tensions will exert different pressure on the rope groove of the traction sheave, so that the rope grooves of the traction sheave wear unevenly. If the time is long, the diameter of each pitch circle will be different, and the relative slip between the ropes will be intensified, causing the running. Vibration and noise will also reduce the life of the traction sheave and wire rope. The compression spring of the rope head combination is not correct. The spring elasticity coefficient is too small, which will increase the vibration amplitude of the car when the elevator is braking. If the spring elasticity coefficient is too large, the impact load capacity will be reduced, which will also increase the vibration of the car. . The twist of the wire rope, the test proves that the twist of the wire rope will cause the elevator to vibrate, and it must be ensured that the rotation of each 30m wire rope does not exceed one turn during installation.
3. Traction machine traction machine is the power source and speed regulation mechanism of the Car Lift, which is very important for the smooth operation of the elevator. It often appears during actual production and installation:
First, due to the no-load operation during the assembly and commissioning of the manufacturer, after the elevator is installed and used, vibration is generated when the load is running. Therefore, when the assembly and debugging of the manufacturer, the load should be appropriately added, and the problem is solved in time.
Second, the assembly does not meet the requirements, the pre-tightening force of the fastening bolt between the reduction box and its traction wheel axle base and the traction machine base may be uneven, which may cause the torque of the reduction gear body to be deformed, resulting in poor meshing of the worm gear pair, the worm and the motor After the connection, the coaxiality exceeds the standard. Therefore, during the assembly, the gear is trimmed and the worm is ground to reduce the vibration.
Third, the worm stiffness is too small, the motor and the worm bearing are worn, and the radial runout is increased.
Fourth, the dynamic balance of the brake wheel and the motor rotor is poor, and the coaxiality of the coupling between the motor and the reducer is low.
Fifth, there are defects in the thrust bearing of the worm shaft end.
Sixth, the gap between the two sides of the electromagnetic brake is not uniform, causing abnormal friction during operation.
Seventh, the unbalanced rotation of the traction sheave is the main vibration source of the mechanical vibration of the traction system. It has been considered in the design and manufacturing process to improve the machining accuracy of the traction sheave.
4. The car is first. When the car is assembled, the vibration-damping and anti-sound rubber pad is not properly installed, which causes great vibration when the car is braking.
Second, the vibration frequency of the car wall is similar to the vibration frequency of the system, and resonance occurs.
Third, the car's own weight is too light, the dynamic performance is poor, and the shielding ability against vibration is poor.
5. The verticality of the Guide Rail, the gauge deviation and the flatness of the joint will affect the comfort during the operation of the elevator. If the deviation of the guide rail is too large, the car will sway horizontally. If it is too small, the car will vibrate vertically. In addition, the rigidity of the rail bracket is not enough, the rail is connected with the bracket, the bracket is welded with the pre-embedded steel plate, and the bracket and the wall are not firmly fixed, and the car is vibrated during operation. Electrical analysis of the motor.
The deviation between the rotor and the stator is too large, and the unbalanced single-sided magnetic pull force is generated by the eccentricity, resulting in vibration; the impedance of each phase loop is unbalanced, resulting in vibration caused by the negative-sequence rotating magnetic circuit, which is generally caused by poor process when the winding is repeatedly repaired. , the number of inconsistent motors.
Drag and control system three-phase power supply voltage or governor output three-phase voltage, the imbalance is greater than 8%; speed feedback device layout is unreasonable and interfered; adjuster P value is too large, I value is too small; adjustment The speed adjustment response filter time selection is not suitable; the governor speed reference signal is unstable or interfered.
The interference of speed feedback is generally used in the closed loop system of elevator speed feedback as the speed feedback signal. The abnormal speed feedback signal is one of the important reasons for system oscillation and mechanical resonance. Such as:
First, the encoder and the motor are poorly connected, causing the feedback signal to be abnormal, causing the elevator to shake;
Second, the encoder should pay attention to cleaning, dust shielding will cause its trigger pulse to be abnormal; 3 encoder should avoid external force impact, the distortion and damage of the disc will make the feedback signal abnormal. Third, the encoder wiring should be reasonable. Ground and shielded wiring should be reliable to avoid external interference feedback signals. Passive vibration reduction treatment of elevators Mechanical treatment measures 1. Install a car compensation device at the bottom of the car, use it to change the center of gravity of the car, balance the car and reduce the pressure of the guide shoe.
2. Install the accompanying cable diagonally.
3. Adjust the rope tie rod nut of the wire rope so that the tension between each wire rope and the average value does not exceed 5%. For elevators with a stroke of more than 30 m, the car is placed in the middle layer during measurement, and the tension value of each wire rope is measured with a spring force gauge at 1.5 m above the car. When the elevator with a stroke of not more than 30m measures the tension of the car wire rope, the car should be placed at the lowest level. When measuring the tension of the heavy side wire rope, the car should be placed at the highest level, and then the wire rope should be measured on the counterweight side. Adjustment.
4. For the vibration generated by the traction machine during constant speed operation, the method of adding the inertia wheel on the traction sheave can be solved. The traction wheel inertia wheel can absorb the energy that causes the vibration of the car, and can eliminate the vibration when the elevator is at the rated speed. , but it is invalid during acceleration and deceleration.
5. Check the condition of the oil once every 3-6 months. When the gear oil is found to be black, mineral deposits and white foam must be replaced immediately. When the gear is worn too much and vibration and noise have been caused, the gear should be replaced. The life of a gear depends on its degree of wear, and the pits on the gear speed up its wear.
6. Adhesive energy is absorbed by the asphalt or damping material on the car wall to reduce the amplitude and noise. It is also possible to fill the sound absorbing material between the car walls and between the car wall and the installation.
7. Lifts with a 1:1 traction ratio should be used.
8. The car guide rail spacing is adjusted by the square iron piece of the standard value bracket width, but the total thickness of the adjusting washer should not exceed 5mm. When adjusting the gasket over two pieces, it should be welded first and then padded. If the step of the rail connection is too large, the car will vibrate and its value should be no more than 0.02mm. If this value is exceeded, the joint shall be polished with a guide planer, and the length of the repair shall not be less than 150 mm. The deviation of the verticality of the guide rail should be no more than 1.5mm per 5m length. If the standard exceeds the standard, the platen and gasket can be used for adjustment. The gap between the guide shoe and the guide rail should generally be adjusted to a gap of 0.5 to 1 mm between the base portion of the fixed guide shoe and the end surface of the guide rail. Comprehensive vibration isolation measures The vibration isolation of the elevator is achieved by the following methods: vibration reduction between the traction machine and the load-bearing beam, vibration reduction between the wire rope and the bridge, and vibration reduction between the car frame and the car:
1. Traction machine and load-bearing beam system In extreme cases, when the frequency of the excitation force is close to or equal to the natural frequency of the system, the system will resonate. The size, size and number of damping pads used for unit isolation must be consistent with the installation documentation or civil drawings. The damping pad is only allowed to be placed between the unit and the concrete (or on the I-beam); the base of the unit must rest on the entire damping pad.
2. The isolation between the car and the car is separated into two parts: the separation of the car bottom and the car frame; the isolation of the straight girder and the bridge. There are three requirements for the isolation of the straight beam splint and the car frame: Only the damping pad connection is allowed between the car frame and the car roof; when the gap between the damping pad and the straight beam exceeds 0.5mm, the damping pad should be replaced.
3. The isolation of the damping pad between the wire rope head and the car frame is determined according to the sum of the rated load and the weight of the car car, and the compression of the damping pad should be 10-15mm when the car is empty; The vibrating pad has no proper effect and can add weight between the wire rope and the damping pad (about 10% of the weight of the car).
4. There are six slings for the car lift, which are corrected by the torsion wrench, so that the tightness of each rope is very close, and the longitudinal vibration of the test rope is basically the same, so that the torsion phenomenon of the car is reduced and the contact with the guide rail is even, and the guide rail is installed. Pressure oil lubrication reduces the amount of dry friction so that vibration and noise are also reduced. Active vibration isolation to control the acceleration and deceleration characteristics and vibration of elevators is the main factor affecting passenger comfort. For example, by reducing the vibration level of the elevator, improving the elevator quality, and improving the comfort, the vibration control of the elevator must be based on in-depth study of its excitation source. On the basis of quantitative analysis of the influence of various factors and parameters on the vibration of the elevator and the sensitivity, it is considered from the three sources of vibration source, transmission path and controlled object. Elevator vibration control can be divided into passive control and active control. At present, most of the vibration control adopts passive control. The elevator vibration control is mainly the following methods. First, replace the currently used motor with a traction motor with good dynamic performance;
Second, changing the stiffness coefficient of some elastic links of the elevator system to change the natural frequency of the system away from the rotational frequency of the traction motor;
Third, installing a dynamic vibration absorber on both sides of the elevator car top wheel to consume the vibration energy of the system, thereby achieving the purpose of vibration reduction;
Fourth, use vibration isolating materials. An in-service, heavy elevator system that replaces motors or elastic components is quite cumbersome. Therefore, it is recommended to use Option 3 to install a dynamic vibration absorber on both sides of the car top to suppress the vibration of the elevator. After the installation of the dynamic vibration absorber in the elevator system, the vertical vibration of the elevator bridge is greatly weakened, reflecting the good vibration damping effect of the dynamic vibration absorber. By reasonably suppressing the vibration source and passive vibration isolation, the vibration level in the car can be effectively reduced, and the general comfort requirements for the medium and low speed (≤2m/s) elevator can be achieved. However, for high-speed elevators and ultra-high-speed elevators, active vibration isolation technology must also be adopted to meet the requirements of comfort. The active vibration isolation system consists of three key parts of vibration signal measurement, real-time controller, and actuator actuator. Active vibration isolation is better, but the cost is higher. Semi-active vibration isolation adjusts the control parameters and stiffness damping parameters of the system in real time according to the vibration state of the elevator.
There are many reasons for the noise generated when the elevator is running. It is a powerful guarantee to control the noise through comprehensive testing, analysis of the causes of noise and corresponding measures. Relevant research shows that only active vibration isolation can effectively control the impact of elevator noise on its surrounding environment.