Author: Mr. elevator

With the rapid development of real estate in China, "elevator" has become an indispensable means of vertical transportation in people's life. In a short period of more than ten years, China's internal elevator industry has experienced the transformation of AC double speed, AC speed regulation, frequency conversion speed regulation, frequency modulation and voltage regulation (3vf), inorganic room and permanent magnet synchronous technology. The road that foreign countries have gone through for more than one hundred years, we have only completed the transformation of technology update in more than thirty years. It is precisely the contradiction caused by the lack of real estate architectural design experience under this rapid development that makes the elevator noise problem very common in the current real estate. With the increasing awareness of the rule of law and health of Chinese people, there are more and more complaints and lawsuits about "elevator noise", and "elevator manufacturers" have become "scapegoats" under the pressure of owners' complaints and "developers". In this paper, the author will combine our company's research and practice in the field of elevator noise control over the years, briefly describe the formation of elevator noise, the treatment methods and technical points, and hope to provide reference for the majority of manufacturers suffering from the elevator industry and noise transmission, and try to avoid some detours when dealing with this problem!

1、 The formation of elevator noise

In the current elevator noise complaints, most of the owners think that "elevator noise" is caused by the poor quality of the elevator itself; they think that "noise" is generated by the elevator, and the problem is definitely related to the elevator, so they should find the elevator company to solve it; even more, they think that they should replace the elevator to solve the problem. However, according to our analysis and Research on elevator noise control cases over the years and communication with relevant architectural design units, it is confirmed that the appearance of elevator noise in the owner's home is mainly due to the fact that the main bearing wall of the elevator machine room and the owner's bearing wall are made into a public wall or the steel connection of the wall is realized when the beauty of the building itself and the saving of public area are considered in the design of the house. Because the noise of the elevator is mainly low-frequency vibration, which is transmitted by solid vibration, the steel connecting wall in the architectural design provides a transmission way for the vibration noise of the elevator. If the load-bearing wall of the machine room is separated from the main wall of the owner's home by adding staggered floors or setting stairwell separation, the problem of elevator noise can be solved. Moreover, it can be noted that there are many architectural design companies in South China that have realized the above problems and made design modifications!

At present, the impact of elevator noise in China is mainly residential. In order to save the cost, the developer generally selects the elevator with worm wheel and worm wheel, which has relatively large noise and vibration; secondly, in order to expand the sales area as much as possible, the developer shares a structural wall between the owner's bedroom or living room and the elevator shaft in the house type design, and designs the top-level elevator machine room directly below the top-level owner's home or Adjacent partitions, etc., which cause sound transmission of structural solids. Although the vibration level to the room is not high, the narrow-band low-frequency sound is easy to annoy people! In the daytime, due to the high ambient noise around, people don't feel the elevator running noise very obvious. In the evening, the situation is more serious. When people are resting indoors in the dead of night, it is easy to affect the normal rest of the residents downstairs of the machine room due to the low-frequency vibration noise of the elevator, thus causing complaints. This situation is more obvious especially in winter when the doors and windows are closed.

2、 Classification of elevator noise

According to the classification of "sound source" of elevator noise, there are two main types of elevator noise: 1. Structural noise of elevator machine room: the elevator machine room is above the owner's room, the next door or the main bearing wall of the elevator host and the main wall of the owner's house form a rigid building structure connection, which forms the main "sound bridge" of elevator noise transmission, making the elevator run and stop at high speed The low-frequency vibration and noise when driving are introduced into the owner's home through the sound bridge. This kind of case is the most common type at present. Generally, the residents of the top floor or the sub top floor are affected by the noise, while the owners of other floors are not affected. However, the noise exists when the main elevator is running. 2. Elevator shaft structure sound transmission: the wall of the elevator shaft and the owner's home are a public wall. The structure of the shaft is poor due to the small holes embedded in the building's line pipe during construction. The air flow noise and car moving noise caused by the vibration of the elevator during high-speed taxiing and the shaft piston effect are transmitted to the owner's home through the fixed bracket and wall of the guide rail. At present, the proportion of such cases is relatively small. Generally, the residents of all floors in the middle are affected. Moreover, when the elevator passes through its corresponding area, it will generate a large noise, which is relatively less affected than the noise in the machine room.

At present, the mainstream products in the elevator market mainly include frequency modulation, voltage regulation, speed regulating elevator (also called 3vf), permanent magnet synchronous small machine room elevator and inorganic room elevator. In contrast, the impact of the permanent magnet synchronous small machine room elevator and inorganic room elevator is relatively small due to the small noise and vibration of the equipment itself. This chapter mainly introduces the sound transmission technology of the machine room structure in the frequency conversion elevator with worm and gear.

3、 Why is it so difficult to control elevator noise?

Elevator noise is different from general noise. Because of low-frequency noise pollution, it is accompanied by slight vibration pollution: "general noise is air as sound transmission medium, and elevator noise is mainly low if vibration, its main transmission way is vibration solid sound transmission". Therefore, the conventional methods of sound insulation board, sound absorption cotton or sound insulation wall can only