是电动提升机的一种。 Multifunctional hoist is a kind of electric hoist. Electric hoist: a hoist that uses a motor as its power to rotate the drum through a driving device.
The scale and power of the hoist used in construction projects will be larger and larger, and the traction speed will be faster and faster. Correspondingly, the size of the open gear pair structure of the key transmission parts of the hoist will become larger and larger. The noise of the hoist is also getting higher and higher under high speed operation, but this is not allowed by national standards. The national standard GB1955-2002 for building hoists stipulates that the qualified hoist noise limit is no more than 85dB (A) outside the machine and no more than 88dB (A) at the ear of the operator. When the traction force of the hoist is small and the speed is low, its noise is far below the standard limit, and the control is also easy; but when the traction speed is high and the traction force is large, to ensure that the noise does not exceed the standard, the design, technology, materials, Effective measures are taken in all aspects such as quality inspection.
There are many ways for the source of hoist noise, but it is essentially the result of impact and vibration. Generally it is caused by the poor meshing quality of the gears and the unstable movement, which results in instantaneous acceleration during the movement. An 80kN fast slideable hydraulic control hoist of our company has a wire rope traction speed of 30m / min and a motor power of 55kW. The machine noise is generally within the standard range, but occasionally the noise exceeds the standard, and a few machines fail the factory inspection. I feel unable to get started when eliminating noise. Because the drawings and process flow of the machine manufacturing are the same, since most products are qualified, the design and process should be excluded.
Chassis We think that the design and manufacturing of the chassis may cause noise: ① The chassis adopts a box-shaped structure, and not all welds are continuously welded. The length, height, and position of the welds on each chassis are different, and there are large individual differences in chassis rigidity. A resonance effect will occur, and the machine will be amplified if there is a little vibration noise; ② The chassis is welded from steel and does not have the shock absorption and muffling function. If its natural frequency is close to the gear meshing frequency, it may cause individual machines to cause large vibrations due to weak gear vibrations. Co-shocks cause noise levels to rise. We conducted separate experiments for the above possibilities, but through three experiments, we found that the noise level is weakly related to the chassis structure, stiffness, frequency and other factors, and the noise level is strongly related to the moving parts. Therefore, the chassis design structure and manufacturing quality are not excessive the reason.
Bearing clearance Some people think that since the noise is accompanied by the reel assembly and transmission parts, it may be caused by the reel sliding bearing gap. We select the matching clearance of the reel parts to ensure that the clearance between the bearing hole and the main shaft meets the requirements of the drawing, and then test after assembly. During the test, a variable frequency motor was used to adjust the speed, and the effect of speed on noise was observed. A large number of test results show that the speed has a significant impact on noise. The higher the drum speed, the larger the noise value and the more intense the machine vibration. The gap is next. The larger the gap between the spindle and the sleeve, the larger the noise. Minimal impact on noise. If the machine's original noise is very low, then the high and low speeds and changes in the size of the spindle clearance will not produce excessive noise, which indicates that the excessive noise is not caused by the large bearing clearance.
Tips: In order to avoid purchasing risks, it is recommended that you confirm the supplier's qualification and product quality before purchasing products.