Motor and reducer of mixing equipment structure

1 The mixing shaft of the motor mixing equipment is usually driven by the motor Because the speed of the mixing equipment is generally low, the motor is mostly combined with the transmission, and sometimes the frequency converter is also used for direct speed regulation Therefore, when selecting the motor, the matching problem with the transmission should be specially considered Generally, the model of the motor shall be selected according to the power of the mixing shaft, the working environment around the mixing equipment and other factors, and the following basic principles shall be followed: ① the type of the electric motor shall be selected according to the starting, braking, operation, speed regulation and other requirements of the motor according to the load nature and process conditions of the mixing equipment ② According to the requirements of load torque, speed change range and starting frequency, considering the temperature rise limit, overload capacity and starting torque of the motor, the capacity of the motor shall be reasonably selected and the cooling and ventilation mode shall be determined At the same time, the selected motor model and rated power shall meet the requirements of starting power increase when the mixing equipment is started ③ According to the environmental conditions of the place of use, such as temperature, humidity, dust, rain water, gas, corrosion, inflammable and explosive gas, etc., the necessary protection methods and the structural type of the motor shall be considered to determine the explosion-proof grade and protection grade of the motor For gas or steam explosion hazardous environment, the structure type and corresponding level and group of explosion-proof motor shall be selected according to the division level of explosion hazardous environment and the level and group of gas or steam in explosion hazardous area and the use conditions of motor; for dust explosion hazardous environment, the division level and use conditions of motor shall be selected according to the division level of explosion hazardous environment The structure type and corresponding explosion-proof and protection grade of the explosion-proof and protection motors; for the fire hazard environment, the structure type and corresponding protection grade of the protection motors shall be selected according to the partition grade of the fire hazard environment and the use conditions of the motors In case of chemical corrosion environment, the appropriate motor shall be selected according to the classification of corrosion environment ④ According to the voltage standard of power grid and the requirement of power factor, the voltage level of motor is determined ⑤ According to the Zui high speed of the mixing equipment and the performance requirements of the transition process of the electric drive speed control system, as well as the complexity of the mechanical deceleration, the rated speed of the motor is selected In addition, the selection of motor must also meet the requirements of energy conservation, and comprehensively consider such factors as operation reliability, supply, universality of spare parts, ease of installation and maintenance, product price, operation and maintenance costs 2 The transmission is an independent closed transmission between the prime mover and the working machine Its main function is to reduce the speed and increase the torque accordingly Since the operation speed of the mixing shaft is mostly in the range of 30-600rpm, which is less than the rated speed of the motor, the transmission is mostly required at the outlet end of the motor According to the transmission capacity, the transmission can be divided into reducer and CVT According to the characteristics of transmission and structure, the reducer can be divided into four types: cycloid pin gear reducer, gear reducer, worm gear reducer and belt reducer Proper transmission shall be selected according to process requirements and operation environment The selected transmission shall not only meet the requirements of power and output speed, but also be reliable in operation, convenient in maintenance, with high mechanical efficiency and low noise 2.1 cycloid pin gear reducer the cycloid pin gear reducer applies the principle of planetary transmission and uses cycloid pin gear engagement It is an advanced design and novel structure reduction mechanism that allows forward and reverse operation It is widely used in petrochemical industry, light industry, food industry, pharmaceutical industry, textile printing and dyeing, metallurgy and mining industry, sewage treatment and engineering machinery, etc Zui of planetary gear reducer is characterized by high transmission efficiency, wide transmission ratio range, transmission power from 10W to 50000kw, and much smaller volume and weight than ordinary gear reducer and worm reducer However, its structure is complex and its manufacturing accuracy is high 2.2 gear reducer gear reducer includes cylindrical gear reducer and bevel gear reducer Among them, cylindrical gear reducer is widely used in all reducers Its power transmission range can be from very small to 4000kW, and its peripheral speed can also be from very low 60-70m / S; and the position of the input shaft and output shaft of the bevel gear reducer is 90o Configuration, so it is suitable for the situation that the input and output shafts are perpendicular to each other The main features of gear reducer are high efficiency, durable operation, simple maintenance port, which can be divided into single-stage, two-stage, three-stage or even multi-stage according to the number of reduction gears, vertical and horizontal according to the mutual configuration of their shafts in the space, expansion type, coaxial type and split type according to the characteristics of its motion diagram, etc In order to avoid the oversize of the reducer, generally when the transmission ratio is below 8, single-stage gear reducer can be used When the transmission ratio is greater than 8, Zui should choose two-stage or more gear reducers 2.3 worm gear reducer the worm gear reducer is mainly used in the occasions with large transmission ratio It has the advantages of compact transmission structure, small outline size and stable operation, but its efficiency is relatively low, so the single-stage worm reducer is widely used, while the two-stage worm reducer is rarely used The range of transmission ratio of single-stage worm reducer is generally 10-70 2.4 belt reducer belt reducer has the characteristics of high efficiency, long service life, compact structure, stable transmission, convenient disassembly, etc it allows positive and negative operation, and is widely used in large-scale fermentation plant 2.5 in a considerable number of mixing operations, the CVT is often used because of the variable speed operation of the mixing shaft required by the process conditions or the uncertain rotating speed of the mixing shaft caused by the trial and research stage of the mixing process Mechanical continuously variable transmission (CVT) mostly uses the friction (traction) force transmission at the contact between the main power component and the driven component to transmit the movement and torque, and realizes CVT by changing the relative position of the main and driven components to change the soil radius at the contact The main function of CVT is to adjust the working speed at any time according to the actual needs of production, so as to obtain the appropriate speed of Zui, that is, its transmission ratio can be changed steplessly within the designed range, so as to simplify the transmission structure, improve the production efficiency and product quality, and reasonably use the kinetic energy At the same time, it can realize the remote control and automatic control functions, and reduce the labor intensity of operators Degree CVT has the following characteristics: ① simple structure Most of the planetary friction CVT consists of 6-8 key transmission elements, which are small in number and compact in structure The overall dimension is small, and the whole machine is relatively easy to manufacture ② The speed range is large The transmission structure can be simplified, the transmission is stable and the noise is very low ③ The driving power is large and the bearing capacity is strong ④ Excellent output mechanical properties In general, the constant torque output characteristic of CVT is strong at low speed, and constant power output can be achieved at high speed ⑤ High transmission efficiency and long service life of mechanism The normal service life can be more than 10 years Because of the above characteristics, and it belongs to the reduced speed drive, so it is widely used in the mixing equipment It is worth noting that compared with gear transmission, mechanical continuously variable transmission has poor overload capacity, and there are sliding, loss of rotation and other phenomena in the working process Therefore, the service life of the transmission will be reduced under the conditions of large starting torque, many starting times, large load variation, impact load and emergency braking In consideration of these factors, a factor can be multiplied on the basis of rated power or torque, that is to say, a stepless transmission with a certain margin, which is slightly larger than the original specification, or a protective device can be set, and the transmission shall be avoided from severe load conditions as far as possible in structure.