Analysis of noise source and its control

With the fast expend scale of national transportation infrastructure and urban construction, winch size is becoming bigger, power rate is more higher, and pulling speed becomes quicker.
As a result, key motive part- drum of winch is becoming bigger. Under high power rate and speed condition, the noise of winch is more loudly. However, it is not allowed for most countries, and for China, the government come out a policy GB1955—2002 file. And it rule that qualified construction winch should limit its off-line noise under 85dB(A), and noise for operator should lower than 88dB(A). Moreover, when use lower pulling power and slower speed of winch, its noise should far below standard, for it is easy to control. But, when using a high pulling power and fast speed winch, to make it attach to standard, engineer should adopts useful solutions from design, material, technology and quality testing.


For two reasons that experts think that mount may cause noise. Firstly, winch mount adopts to box type structure, not all welds are welded. Besides, every welding joint has different size and height, and steel strength has individual difference. Moreover, some mount may has resonance effect. If pulling produce little shack, then the noise will be magnified. Secondly, mount is soldered by steel plate, which has no shock absorption function. It will arose strong resonance if its inherent frequency close to gear mesh frequency because of gear weakness, and then noise rate will increase.

Bearing clearance

Some people think that as noise come out with drum and transmission part, so that the drum sliding bearing clearance may be the reason of noise. After check of drum parts clearance and ensure bearing hole and shaft clearance conform to drawing requirement, experts make a test after assembling. Experts choose a frequency conversion motor to change speed to observe how speed affects noise. According to large number test, speed has decisive influence to noise. The faster the drum spans, the more noise it made, and the winching machine shacks more strong. Bearing clearance ranges the second place to influence noise, the bigger the clearance between principle axis and axle sleeve, the stronger of noise. What is more, mount has smallest influence, if rope winch itself has little noise, and no matter speed fast or slow, the change of bearing clearance has little effect on noise. So evidence shows that noise exceed standard is not caused by bearing clearance.

Though we have many standard to a winch machine, there is still problem. There are many ways to lead to noises of a pulling winch, but noise comes from shack and shock essentially. In most situation, noises are made because that poor quality and unbalance movement produce instantaneous acceleration when operate a winching machine. Take a 80 KN fast rope winch for example, the pulling speed of its wire rope is 30m/min, and the rate of its motor is 55KW, noises is under limitation, however, noise is too loud sometimes occurred, so that little rope winch cannot pass quality test only to be failed. To this case, because that all machine in the same type adopt the same blueprint and technological process, and the most qualified, for the rest, design and technology reason should be removed.