Analysis of transmission scheme
The belt bucket elevator is generally composed of prime mover, transmission and working device.Transmission device is used to transfer the prime mover motion and power, change its motion form to meet the needs of the working device, is an important part of the machine.Whether the transmission device is reasonable will directly affect the performance, weight and cost of the machine.In addition to meeting the function of the working device, the reasonable transmission scheme also requires simple structure, convenient manufacture, low cost, high transmission efficiency and convenient maintenance.Design the original motor for the motor, the working machine for the belt conveyor.The transmission scheme adopts two-stage transmission, the first-stage transmission is belt transmission, and the second-stage transmission is single-stage straight tooth cylindrical gear reducer.Low carrying capacity of belt transmission.When the same torque is transferred, the structure is larger in size than other forms, but has the advantage of overload protection, which can reduce the impact and vibration.Therefore, it is set in the high speed transmission stage, in order to reduce the transmission torque, reduce the structural dimension of belt transmission.Gear transmission is one of the most widely used mechanisms in modern machines because of its high transmission efficiency, wide range of applicable power and speed, and long service life.The design adopts single tooth cylindrical gear transmission.The reducer housing adopts horizontal split structure and HT200 gray cast iron casting.Design of driving system parameters.Original data: the working force of the belt bucket elevator is F=2200N;Belt speed V=1.8m/s;Drum diameter D=400mm (drum efficiency is 0.96).Working conditions: Expected service life of 5 years.Motor Selection 1. Motor type: Y series three-phase asynchronous motor
2. Motor Power selection:
(1) Transmission device: ETA total efficiency =0.96*0.99* 0.98*0.98*0.98*0.98*0.95*0.96=0.84 Input power required by the belt bucket elevator: Because F=2200NPd=FV/1000× eating a little pie 2000×1.8/1000×0.84= 3.96kW motor output power:=3.04/0.84=4.71KW Make the motor rated Power P(1~ 1.3kW)P, according to the table, the motor rated power P= 5.5kW.
(2) Determine motor speed: Calculate the working speed of the drum: NW=60×1000/3.14×450r/min.According to the recommended reasonable range of transmission ratio, take the range of transmission ratio of the first stage reducer driven by cylindrical gear I '=3~6.Take V with transmission ratio I '=2~4, then the range of the total transmission ratio is I' =6~24.Therefore, motor speed range of optional for N = (6 ~ 24) x 76.43 ', 458.58 ~ 1834.32 r/min, (3) in the motor synchronous speed 1000 r/min and 1500 r/min range, according to the calculate and determine the motor model, considering the motor and transmission, but also reduce the weight and cost of the motor, finally the synchronous speed 1500 r/min can be determined, according to the required power rating and synchronous speed motor model for Y132S - 4, 1440 r/min at full speed.Its main performance: Rated power: 5.5KW, full load speed: 1440r/min,
2.rated torque:
(1) Total transmission ratio: I=1440/76.43=18.84
(2) Transmission ratio at all levels: According to the instruction, gear I=4(single stage reducer I=3~6 reasonable);3. Calculation of motion parameters and dynamic parameters: NI=Nm/IO, 960/4=320r/min, NII=NI/I1=320/3.14, 76.43(r/min), Nw=NII for roller III, 76.43(R/min) (2) Calculation of motor rating Pm= 4.71kW for each shaft (KW), so PI=4.71×0.96=4.52k W PII=4.520.99×0.95= 4.25K W PIII=4.25×0.99, 0.99 and 4.71k W
3. Calculation shaft torque (N, mm)*ETA01IO TI=Td=46.85×4×0.96=179.9N, M Tii=TI*ETA12i1=179.9*3.14*0.99*0.95= 531.28n,M TIII=Tiix ETA23=531.28*0.99*0.99*0.99= 520.28n, design and Calculation of gear transmission design and calculation of gear material selection and precision grade consideration, the reduction of transmission power is not big, so the gear adopts soft tooth surface.The gear adopts 40Cr tempering and the tooth surface hardness is 240~260HBS.The big gear is made of 45# steel, tempered.