A winch, also known as a winch, is a light and small lifting device that uses a drum to wrap a steel rope or chain to lift or pull a heavy object. It can lift vertically, horizontally or inclinedly. So what are its structure and noise control?
1. Structure of the winch
The winch converts electrical energy into mechanical energy through the motor 1, that is, the rotor output of the motor, decelerates through the V-belt 2, shaft 3, gears 4, 5 and then drives the drum 6 to rotate. The reel winds the wire rope 7 and passes the pulley sets 8, 9 to lift or drop the load Q of the crane hook 10, transform the mechanical energy into mechanical work, and complete the vertical transportation of the load.
2. Noise control of the winch
The scale of national transportation infrastructure and urban construction is getting larger and larger, the scale and power of the winch used in construction projects are getting bigger and bigger, and the traction speed is getting faster and faster. Correspondingly, the open gear of the key transmission parts of the winch The size of the auxiliary structure is getting bigger and bigger, the noise of the winch is getting higher and higher under the condition of high power and high speed operation, but this is not allowed by the national standard. The national standard for construction hoists GB1955-2002 stipulates that the qualified noise limit of the hoist shall be 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 winch is small and the speed is low, the 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, it is necessary to ensure that the noise does not exceed the standard, from the design, process, materials, quality Take effective measures at various links such as inspection. 1 There are problems: There are many ways to source the noise of the winch, but it is essentially the result of impact and vibration, which is generally caused by the poor quality of the gear mesh and the unstable movement that generates instantaneous acceleration during the movement. An 80kN fast spool hydraulic control hoist of our company has a wire rope traction speed of 30m/min and a motor power of 55kW. The noise of the machine is generally within the standard range, but occasionally the noise exceeds the standard, and a few machines cannot pass the factory inspection. It is impossible to start when removing noise. Because the drawings and process flow based on machine manufacturing are the same, since most 名媛直播 are qualified, the unreasonable design and process factors should be excluded.
Noise source analysis and control
1. Chassis We believe that the design and manufacture of the chassis may cause noise: ① The chassis adopts a box-shaped structure, not all welds are continuously welded, the length and height of each weld of the chassis are different, and there are large individual differences in the chassis rigidity. Some have resonance effects, and the machine will be amplified if there is a little vibration noise; ②The chassis is welded with steel plates and does not have shock absorption and noise reduction functions. If its natural frequency is close to the gear meshing frequency, it may cause individual machines to be caused by weak gear vibration A large common shock causes the noise value to rise. We conducted experiments on the above possibilities separately, 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, construction and manufacturing quality are not the reasons for the noise exceeding the standard. .
2. Bearing clearance Some people think that since the noise is accompanied by the drum assembly and transmission parts, it may be caused by the clearance of the sliding bearing of the drum. We choose the clearance of the parts of the reel to ensure that the clearance between the bearing hole and the spindle meets the requirements of the drawings, and conduct the test after assembly. During the test, the frequency conversion motor is used to adjust the speed, and the effect of speed on noise is observed. A large number of test results show that the speed has the first effect on noise. The higher the drum speed, the greater the noise value and the more violent machine vibration; the gap is second, the larger the gap between the main shaft and the sleeve, the greater the noise; and the chassis Minimal impact on noise. If the noise of the machine is very low, the speed and the change of the clearance of the main shaft will not produce excessive noise, which shows that the excessive noise is not caused by the large bearing clearance.
