Author: Xu Zijian
Abstract: As a modern and efficient means of transportation, the passenger ropeway has the advantages of large transportation capacity and low emissions. However, the noise and vibration issues generated by passenger ropeway machinery and equipment have also received increasing attention. This article describes the causes of noise and vibration of rooftop cableway mechanical equipment and proposes corresponding control and management measures, aiming to improve the operation quality and safety of the passenger cableway and provide tourists with a more comfortable riding experience.
Keywords: passenger ropeway; noise; vibration; control and management
1. Analysis of causes and hazards of noise and vibration failures of mechanical equipment
1. Analysis of equipment noise and vibration fault causes
(1) Equipment design reasons
The equipment may have defects during the design stage, such as unreasonable structure, improper selection of materials, etc., resulting in equipment failure during operation. Inaccurate settings of design parameters such as load, speed, temperature, etc. can cause the equipment to exceed the design range during actual operation, causing malfunctions. The design concept failed to keep up with the pace of modern industrial development, resulting in equipment deficiencies in performance, efficiency and reliability.
(2) Equipment manufacturing reasons
During the equipment manufacturing process, there may be problems in the processing technology, assembly technology, etc., resulting in reduced equipment accuracy and performance. In addition, the raw materials or parts used in the manufacturing process have quality problems, such as insufficient strength and poor wear resistance, making the equipment prone to failure during operation. In addition, there were omissions in the quality inspection process, and potential problems were not discovered and corrected in time, resulting in equipment leaving the factory with diseases.
(3) Reason for device use
During the use of the equipment, due to insufficient skills of the operator or violation of operating procedures, equipment damage or performance degradation is caused. Equipment operating in harsh environments, such as high temperature, humidity, corrosion, etc., will accelerate equipment aging and increase the probability of failure. Overload operation of equipment for a long time will lead to increased wear, temperature rise, performance degradation, and eventually failure.
(4) Equipment maintenance reason
Equipment maintenance plans are not implemented in place, and potential problems are not discovered and dealt with in a timely manner, leading to failures. Maintenance personnel lack necessary professional knowledge and skills. The maintenance methods used by maintenance personnel are incorrect or non-standard, and they are unable to effectively maintain and maintain the equipment, resulting in frequent failures. Not only cannot the problem be solved, but the damage to the equipment may also be aggravated.
2. The hazards of equipment noise, vibration and abnormal sound
(1) Affects device performance
Abnormal noise and vibration produced by equipment during operation are often caused by wear or damage of equipment components. Damage to these components will lead to a decrease in the performance of the equipment, thereby affecting the normal operation of the ropeway equipment.
(2) Accelerates equipment aging
The occurrence of abnormal noise and vibration in equipment will also accelerate the aging process of the equipment. In particular, abnormal noise and vibration in some key components will often lead to faster damage and failure of the equipment, thus reducing the service life of the equipment.
(3) creates a security risk
If abnormal noise and vibration of the equipment are not detected and resolved in time, the equipment is likely to malfunction, which will bring unpredictable safety hazards to the operation of the ropeway.
2. Control and management measures for noise and vibration of mechanical equipment
1.Noise and vibration control of drive devices
(1) Use low-noise motors
When selecting a motor, priority should be given to low-noise, high-efficiency motors. You can choose a motor with a lower noise level by comparing the noise parameters of motors of different brands and models.
(2) Optimize reducer design
The design of the reducer should pay attention to the accuracy and meshing quality of the gears, and adopt reasonable gear parameters and processing technology to reduce gear meshing noise. At the same time, good quality bearings should be selected and good lubrication should be ensured to reduce bearing noise. In addition, the vibration and noise of the box can also be reduced by increasing the rigidity of the box and using shock-absorbing pads.
(3) Install sound enclosure
Installing a soundproof cover around the motor and reducer can effectively reduce the spread of noise. The material of the sound insulation cover should have good sound insulation properties, such as sound-absorbing cotton, sound insulation panels, etc. At the same time, the design of the sound insulation cover should consider ventilation and heat dissipation issues to ensure the normal operation of the motor and reducer.
2. Noise and vibration control of carrier ropes
(1) Optimize the design of the supporting cable pulley and the pressure cable pulley
The design of the supporting cable pulley and the pressure cable pulley should focus on reducing the friction coefficient with the carrying rope. Polymer materials can be used to make the wheel lining to improve the wear resistance and self-lubrication of the wheel lining. At the same time, the installation accuracy of the supporting cable pulley and the pressure cable pulley should be ensured to reduce vibration and noise caused by non-concentricity of the wheel axle and other reasons.
(2) Adjust the tension of the carrying rope
Properly adjusting the tension of the carrying rope can reduce the vibration amplitude of the carrying rope, thereby reducing the generation of noise. When adjusting the tension, the appropriate tension value should be selected based on the design parameters and actual operating conditions of the ropeway. At the same time, the tension of the carrying rope should be checked regularly to ensure that the tension is stable within a reasonable range.
(3) adopts shock absorbing device
Installing shock-absorbing devices, such as spring shock absorbers, rubber shock-absorbing pads, etc., on the supporting parts of the carrying rope can effectively absorb the vibration energy of the carrying rope and reduce the spread of noise.
3.Noise and Vibration Control of Detours and Tensioners
(1) Optimize tensioner control
The control of the tensioning device should adjust the tension in real time according to the operating status of the ropeway to avoid vibration and noise caused by too large or too small tension. Advanced automatic control technology can be used to achieve precise control of tension.
(2) Strengthen equipment maintenance
Regularly maintain the detour device and tensioning device, check the wear of the rollers, the lubrication status of the bearings, etc., and replace damaged parts in a timely manner to ensure the normal operation of the equipment.
4. Noise and vibration control of brackets
(1) Strengthen the structural design of the bracket
The structural design of the bracket should have sufficient rigidity and stability to withstand the operating load of the cableway and external forces such as wind. Reasonable cross-sectional shape and reinforcing rib arrangement can be adopted to improve the wind vibration resistance of the bracket. At the same time, the foundation of the bracket should be ensured to be firm and reliable to avoid vibration and noise caused by uneven settlement of the foundation.
(2) Install shock absorbers
Installing shock-absorbing devices, such as rubber shock absorbers, spring shock absorbers, etc., at the connection between the bracket and the ground can effectively absorb the vibration energy of the bracket and reduce the spread of noise.
3. Summary of Noise and Vibration Treatment of Rooftop Cableway Mechanical Equipment
1.Noise and abnormal sound troubleshooting
(1) Fault phenomenon: During the daytime operation of the hydraulic braking system, it was found that the motor was working normally, but the position of the hydraulic motor was noisy. When the ropeway was restarted after the system was braked, the pressure rose slowly when the ropeway was restarted. After the equipment was running normally, the system pressure was lower than the normal value.
Inspection results: The damping pad of the coupling is worn (as shown in the picture 1), and the upper and lower claws of the coupling are in rigid contact, causing loud noise. The reason is that the operating gap of the hydraulic motor is large after the coupling is worn, causing the system pressure to be lower than the normal value.
Treatment measures: Replace the coupling with a new one and install an elastic shock-absorbing pad.
Figure1 Coupling shock absorber pad wear
(2) Fault phenomenon: During the daytime operation of the carriage, it was found that the cableway 37# carriage made abnormal noises during operation, and this abnormal noise continued to occur.
Inspection results: The carriage was tested and inspected after work, and it was found that the abnormal noise was caused by the aging of the sealing ring inside the damping rod and the leakage of lubricating oil, causing the rod body to make abnormal noise due to dry grinding (as shown in the picture 2).
Treatment measures: Replace the damping rod with a new one, replace the removed damping rod with a new sealing ring, and add lubricating oil.
Figure 2 The damping rod is dry grinding due to lack of oil.
(3) Fault phenomenon: Abnormal noise occurs during operation of the electromagnetic clutch
Inspection results: The clutch inner gear plate frame fixing bolts (as shown in the figure 3) did not reach the tightening torque, resulting in the inner gear plate frame fastening bolts not reaching the tightening torque, resulting in the inner gear plate frame bottom surface (flange surface) and the hollow shaft flange surface not fully fitting (the disc spring did not reach the rated deformation, and the rated friction force between the inner and outer gear plates was not reached). There is relative movement between the friction plates or the sound of air explosion when the friction plates are opened and closed during rotation is abnormal noise during operation.
Treatment measures: When assembling the clutch inner gear rack, retest the fixing bolts to reach the tightening torque.
Figure 3 Clutch inner gear rack fastening bolts
2. Vibration troubleshooting
(1) Fault phenomenon: The roller bearing of the upper station hydraulic tensioning traveling trolley is damaged (as shown in the picture 4), but it does not affect the operation.
Inspection results: The roller bearing of the tensioning trolley has been running in a vibrating environment for a long time, and the bearing has been severely damaged by fatigue. Due to the lack of inspection of these relatively hidden locations, the operation status of these hidden components is not understood, and timely maintenance is not performed.
Treatment measures: Replace the roller bearing (supported cylindrical roller) and strengthen the inspection of hidden parts;
Figure4 Damaged tensioning trolley limit bearing
(2) Fault phenomenon: When the cableway staff passed the 3# bracket during the ride inspection, they found that the bracket had severe resonance, accompanied by sharp metal blasting sounds, which affected the riding experience of passengers.
Inspection results: After inspection, it was found that the guardrail of the 3# bracket was fatigued and broken under long-term vibration environment due to material defects (as shown in the picture 5), and the fixing bolts of the walking platform part of the bracket were loose.
Treatment measures: Remove the broken part, weld it and do anti-rust galvanizing treatment, and retighten all the fixing bolts of the walking platform.
Figure 5 The bracket guardrail is broken
(3) Fault phenomenon: During normal operation of the ropeway, the match between the natural frequency of the wire rope and the ropeway system and the external excitation frequency may cause resonance, affecting the passenger's riding experience.
Treatment measures: Adjust the ropeway operating speed under high vibration conditions to avoid resonance, evenly distribute passengers, improve system stability, and reduce the risk of resonance.
(4) Fault phenomenon: During daily inspections, staff found that the protective cover vibrated abnormally and made a metal impact sound.
Inspection results: After inspection, it was found that the rubber shock-absorbing pad at the fixed stuck point of the protective cover was aged and cracked, causing abnormal noise when the protective cover hit the fixed stuck point.
Solution: Replace with a new rubber shock-absorbing pad (as shown in the picture 6), and wrap a circle of tape around the thread to fix it.
Figure 6 New rubber shock absorber
4. Conclusion
Noise and vibration control in passenger ropeway mechanical systems is a comprehensive issue that must be addressed through design, manufacturing, installation, operation, and maintenance. Selecting low-noise equipment, optimizing structural design, and adopting vibration and noise reduction measures can effectively lower noise and vibration, improve ropeway operating quality and safety, and provide tourists with a more comfortable ride. These measures also help reduce effects on the surrounding environment and support sustainable development of passenger ropeways.
This article is selected from the papers of 2024 National Ropeway Annual Conference
Source: Jiuhua Tourism Ropeway Technical Exchange
(Copyright belongs to the original author or institution)