Discussion on various types of reducer technology
The reducer is a power transmission mechanism that uses a gear speed converter to reduce the number of revolutions of the motor (motor) to the required number of revolutions and obtain a larger torque. In the current mechanism used to transmit power and motion, the application range of the reducer is quite wide. It can be seen in almost all kinds of mechanical transmission systems, from ships, automobiles, locomotives, heavy machinery used in construction, processing machinery and automatic production equipment used in the machinery industry, to the common ones in daily life Home appliances, clocks, etc. Its applications range from the transmission of large power to small load and precise angle transmission. The application of the reducer can be seen. In industrial applications, the reducer has the function of reducing speed and increasing torque. Therefore, it is widely used in speed and torque conversion equipment. The main functions of the reducer are:
1) Decrease speed and increase output torque at the same time. The torque output ratio is the motor output multiplied by the reduction ratio, but be careful not to exceed the rated torque of the reducer.
2) Deceleration reduces the inertia of the load at the same time, and the reduction in inertia is the square of the reduction ratio. You can see that a general motor has an inertia value.
The working principle of the reducer
The reducer is generally used for low-speed and high-torque transmission equipment. The power of the electric motor, internal combustion engine or other high-speed running is achieved by the gear with a small number of teeth on the input shaft of the reducer and the large gear on the output shaft to achieve the purpose of deceleration. The reducer will also have several pairs of gears with the same principle to achieve the desired deceleration effect. The ratio of the number of teeth of the large and small gears is the transmission ratio.
Types of reducers
The reducer is a relatively precise machine. The purpose of using it is to reduce the speed and increase the torque. It has a wide variety of different models, and different types have different uses. There are many types of reducers. According to the transmission type, they can be divided into gear reducers, worm reducers and planetary gear reducers; according to the number of transmission stages, they can be divided into single-stage and multi-stage reducers; according to the gear shape, they can be divided into cylindrical gear reducers. The speed reducer, the bevel gear reducer and the bevel-cylindrical gear reducer; according to the arrangement of the transmission, it can be divided into the expansion type, the split type and the coaxial type reducer. The following are commonly used reducer classifications:
⑴ Cycloidal pinwheel reducer ⑵ Hard tooth surface cylindrical gear reducer ⑶ Planetary gear reducer ⑷ Soft tooth surface reducer ⑸ Three-ring reducer ⑹ Crane reducer ⑺ Worm reducer ⑻ Shaft-mounted hard tooth surface reducer ⑼ None Speed transmission
The main feature of the worm gear reducer is that it has a reverse self-locking function and can have a larger reduction ratio. The input shaft and the output shaft are not on the same axis or on the same plane. But generally the volume is large, the transmission efficiency is not high, and the accuracy is not high. The harmonic drive of the harmonic reducer uses the controllable elastic deformation of the flexible element to transmit movement and power. The volume is small and the accuracy is high. However, the disadvantage is that the flexible wheel has limited life and is not resistant to impact. The rigidity is compared with metal parts. difference. The input speed cannot be too high. The advantages of planetary reducer are compact structure, small return clearance, high precision, long service life, and large rated output torque. But the price is slightly more expensive.
Features of cycloid reducer
The planetary cycloid reducer is a kind of planetary transmission principle, adopts the cycloidal pin wheel meshing, advanced design and novel structure. In most cases, this kind of reducer has replaced two-stage and three-stage ordinary cylindrical gear reducers and cylindrical worm reducers. It is used in military, aerospace, metallurgy, mining, petroleum, chemical, shipbuilding, light industry, food, textile, Printing and dyeing, pharmaceuticals, rubber, plastics, and lifting and transportation have been increasingly widely used.
1. Product features
1. The transmission ratio is large. The transmission ratio is 1/6-1/87 in the first deceleration. The transmission ratio for two-stage reduction is 1/99--1/7569; for three-stage transmission, the transmission ratio is 1/5841-1/658503. In addition, multi-stage combination can be used according to needs, and the speed ratio can reach the specified value.
2. High transmission efficiency. Because the meshing part adopts rolling meshing, the general first-level transmission efficiency is 90%-95%.
3. Compact structure, small size and light weight. Compared with ordinary cylindrical gear reducer, the volume can be reduced by 2/1-2/3.
4. Fewer failures and long life. The main transmission engaging parts are made by grinding bearing steel, so the mechanical properties and wear resistance are good, and because it is rolling friction, there are few failures and long life.
5. Smooth and reliable operation. Because of the multi-tooth meshing during the transmission process, it runs smoothly and reliably with low noise.
6. Convenient disassembly and assembly, and easy maintenance.
7. Strong overload capacity, impact resistance, small moment of inertia, suitable for frequent starting and forward and reverse rotation.
2. Technical specifications
1. Machine model:
According to the transmission ratio, it is divided into: first, second, and third.
There are thirteen types of level one: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12.
There are 14 models in two levels: 00, 20; 32, 42, 53, 63, 64, 74, 84, 85, 95, 106, 117, 128.
There are 8 models for the third level: 420, 742, 842, 853, 953, 1063, 1174, 1285.
According to the structure type, it is divided into four types: horizontal type, vertical type, double-shaft type, and direct-coupled type.
2. Transmission ratio:
The transmission ratios of the first reduction are: 9, 11, 17, 21, 23, 25, 29, 35, 43, 47, 59, 71, 87.
The two-stage reduction gear ratios are: 99, 121, 187, 289, 319, 385, 473, 493, 595, 649, 731, 841, 1003, 1225, 1505, 1849, 2065, 2537, 3045, 3481, 5133.
The transmission ratio of the three-stage reduction is: 5841-658530
The development of reducer
From the 1970s to the 1980s, the world's reducer technology had a great development, and it was closely integrated with the development of the new technological revolution. The development trend of general reducer is as follows:
①High level and high performance. Cylindrical gears generally adopt carburizing, quenching and tooth grinding, and the carrying capacity is increased by more than 4 times, with small size, light weight, low noise, high efficiency and high reliability.
②Building block type combination design. The basic parameters adopt the priority number, the size specifications are neat, the parts are universal and interchangeable, the series is easy to expand and the pattern is renovated, which is conducive to the organization of mass production and the reduction of costs.
③Diversified types and many variant designs. Get rid of the traditional single base installation method, add hollow shaft suspension type, floating support base, integrated connection of motor and reducer, multi-directional mounting surface and other different types to expand the scope of use.
The main factors that promote the improvement of the reducer level are:
①Theoretical knowledge is getting better and closer to reality (such as gear strength calculation method, modification technology, deformation calculation, optimization design method, smooth transition of tooth root, new structure, etc.).
②Adopt good materials and generally use various high-quality alloy steel forgings, and the quality control level of materials and heat treatment is improved.
③The structure design is more reasonable.
④The machining accuracy is improved to ISO5-6 level.
⑤The bearing quality and life are improved.
⑥The quality of lubricating oil is improved.
Since the 1960s, my country has successively formulated standards for a number of general-purpose reducers such as JB1130-70 "Cylindrical Gear Reducer". In addition to self-made and matched use by OEMs, a number of professional reducer manufacturers have also been formed. At present, there are hundreds of companies producing reducers across the country, with an annual output of about 250,000 general-purpose reducers, which have contributed to the development of my country's mechanical products.
Most of the reducers in the 1960s were made with reference to the technology of the Soviet Union in the 1940s and 1950s. Although they were developed later, they were limited to the design, technological level and equipment conditions at that time, and their overall level was far from the international level .
Since the reform and opening up, my country has introduced a batch of advanced processing equipment, and gradually mastered the design and manufacturing technology of various high-speed and low-speed heavy-duty gear devices through the introduction, digestion, and absorption of foreign advanced technology and scientific research. Material and heat treatment quality and gear processing accuracy have been greatly improved. The manufacturing accuracy of general cylindrical gears can be increased from JB179-60's 8-9 level to GB10095-88's level 6, and the manufacturing accuracy of high-speed gears can be stabilized at 4-5 level. After some reducers adopt hard tooth surfaces, the volume and mass are obviously reduced, and the carrying capacity, service life, and transmission efficiency have been greatly improved, which plays a great role in energy saving and improving the overall level of the host.
The power of the high-speed gear reducer (increase) designed and manufactured in our country has reached 42000kW, and the gear circumferential speed has reached more than 150m/s. However, the technical level of most reducers in my country is not high, and old products cannot be replaced immediately. The coexistence of new and old products will take a long time.
Design procedure of reducer
1. The original information and data of the design
1. The type, specification, speed, power (or torque), starting characteristics, short-time overload capacity, moment of inertia, etc. of the prime mover.
2. The type, specification, purpose, speed, power (or torque) of the working machine. Work system: constant load or variable load, variable load load diagram; starting, braking and short-term overload torque, starting frequency; shock and vibration degree; rotation direction, etc.
3. The connection mode of the prime mover and the reducer, whether the shaft extension has radial force and axial force.
4. Installation type (relative position of reducer and prime mover, working machine, vertical type, horizontal type).
5. Transmission ratio and its allowable error.
6. Requirements for size and weight.
7. Requirements for service life, safety and reliability.
8. Environmental conditions such as ambient temperature, dust concentration, air velocity, and pH; lubrication and cooling conditions (whether there is circulating water, lubrication station) and restrictions on vibration and noise.
9. Requirements for operation and control.
10. The source and inventory of materials, blanks, standard parts.
11. The manufacturing capacity of the manufacturing plant.
12. Requirements for batch size, cost and price.
13. Delivery deadline.
The first four items mentioned above are necessary conditions. Other aspects can be designed according to conventional rules. For example, the design life is generally 1 year. When used in important occasions, the reliability should be higher.
2. Select the type and installation type of the reducer
3. Preliminary determination of various process methods and parameters
Select the performance level, tentatively determine the materials, heat treatment process, finishing method, lubrication method and lubricating oil of gears and main parts.
Fourth, determine the number of transmission stages
According to the total transmission ratio, determine the number of transmission stages and the transmission ratio of each stage.
Five, initial geometric parameters
Preliminary calculation of gear transmission center distance (or pitch circle diameter), modulus and other geometric parameters.
Six, overall plan design
Determine the structure of the reducer, the size of the shaft, the span and the bearing model, etc.
Seven, school
Check the strength of load components such as gears, shafts, keys, etc., and calculate bearing life.
8. Lubrication and cooling calculation
Nine, determine the accessories of the reducer
10. Determine the carburizing depth of gears
If necessary, calculation of process data such as tooth profile and tooth profile modification amount should be performed.
11. Draw construction drawings
The relevant national and industry standards should be implemented in the design.
