Under modern technology, the power output of equipment such as internal combustion engines and motors is getting stronger and stronger, but without the cooperation of the precision gear of the reducer, the efficiency of the operation will be affected.
What is a reducer?
The reducer is an independent closed transmission device between the prime mover and the working machine, used to reduce the speed and increase the torque to meet the needs of various working machines.
In the process of industrial manufacturing, it should not be necessary to produce more products at the same time. Why use a reducer instead of an accelerator? The main function of the reducer in the industry is to decelerate, that is, to reduce the use of machinery. In the speed, the purpose of using it is to reduce the speed and increase the torque. It uses the electric motor, internal combustion engine, or other high-speed running power through the gear with a small number of teeth on the input shaft of the reducer to mesh with the large gear on the output shaft to achieve the purpose of deceleration.
In the current industrial use, the application range of the reducer is quite wide. For example, gear reducers can be seen in almost all types of mechanical transmission systems, from vehicles, ships, automobiles, locomotives, and heavy machinery used in construction. The principle of bicycles is also like that of reducers. It is used in the machinery industry. The processing machines and automated production equipment, to the common household appliances, clocks, and watches in daily life. Its applications range from the transmission of large power to the transmission of small loads and precise angle transmission. The application of the reducer can be seen, and it is also used in industrial applications. Above, the reducer has the function of decelerating and increasing torque. Therefore, it is widely used in speed and torque conversion equipment. For example, the elevators we make every day use a worm gear reducer.
Overview of the operation principle of the reducer
The reducer is a type of transmission. It is generally used for low-speed and high-torque transmission equipment. The principle is to engage the electric motor, internal combustion engine, motor, or other high-speed running power through the gear with fewer teeth on the input shaft of the reducer to mesh with the large gear on the output shaft. Gear is a mechanism that reduces the number of revolutions of a power device such as a motor to the required number of revolutions and obtains a larger torque. In other words, the reducer is a kind of transmission mechanism that can reduce the speed of the motor and increase the output torque. The transmission principle is as shown in the figure below. Now only a small force is given to the input end after several gears are transmitted. It can produce a larger force to drive a large load. The ratio of the number of teeth of the large and small gears is the reduction ratio (transmission ratio).
The reducer is an independent component composed of gear transmission, worm gear transmission, gear-worm transmission, cycloid gear, and planetary gear enclosed in a rigid shell. It is often used as a reduction transmission device between the original moving part and the working machine.
It plays a role in matching the speed and transmitting torque between the prime mover and the working machine or the actuator. It is widely used in modern machinery. The reducer can be divided into single-stage and multi-stage reducers according to the number of transmission stages. The gear shape can be divided into cylindrical gear reducer, bevel gear reducer, and conical-cylindrical gear reducer; according to the transmission arrangement form, it can be divided into expansion Type, split-flow, and co-entry shaft reducer.
The following two points can be achieved by using a reducer
- Reduce the speed and increase the output torque at the same time. The torque output ratio is the motor output multiplied by the reduction ratio, but it should be noted that the rated torque of the reducer cannot be exceeded.
- 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 reducer is a relatively precise machine. At present, there are gear reducers, worm gear reducers, worm reducers, worm gear reducers, planetary reducers, and cycloid pinwheel reducers. The installation method is also different, there are two types of vertical and horizontal. The matched power supply methods also have their characteristics.
The difference between a geared motor and a reducer
Reduction motors, also known as gear reduction motors and gear motors, are modular combinations. They are combined with a motor and a reducer. At the same time, the output torque is increased. The gear mechanism or other mechanisms (such as cycloidal gears or planetary gears) make the speed of the motor drops.
The output speed of the motor is 4 poles (output synchronous speed 1800rpm), 6 poles (output synchronous speed 1200rpm), 8 poles (output synchronous speed 900rpm) or the torque cannot meet the actual requirements because the speed used by the equipment is generally relatively small. Motors, the higher the number of poles, the more expensive they are. Common motors generally use 4 poles.
The benefits of using a reducer
There are many ways to increase the output torque. The increase of the torque is equal to the increase of the control motor current. At this time, a relatively large driver and power electronic components must be used to match. This will make the overall control system Increased costs. Because when choosing a larger wattage motor, the size of the motor will become larger. On the contrary, to install the motor, the whole mechanism will become larger and larger. As the equipment becomes larger and larger, it also needs more Space to place equipment, the cost has risen linearly. At this time, if a reducer is used to increase the torque, the torque can be increased without too much motor.
Common types of reducers
- Single-stage cylindrical gear reducer:
A single-stage cylindrical gear reducer is suitable for a reduction ratio of 3~5. The gear teeth can be straight, helical teeth, or herringbone teeth. The box is usually cast iron or welded by steel plates. Rolling bearings are commonly used for bearings, and sliding bearings are only used for heavy loads or extremely high speeds.
- Two-stage cylindrical gear reducer:
Two-stage cylindrical gear reducers are divided into three types: expansion type, split type, and coaxial type, suitable for reduction ratios of 8-40.
- Expansion style: high-speed long-tail helical gear, low-speed gear can be straight or helical gear. Due to the asymmetrical arrangement of the gear relative to the bearing, the rigidity of the shaft is required to be large, and the torque input and output ends are far away from the gear to reduce the uneven distribution of load along the tooth width caused by the bending and deformation of the shaft. Simple structure and most widely used.
- Shunt type: High-speed shunt is generally used. Because the gear is arranged symmetrically concerning the bearing, the force on the gear and the bearing is more even. To make the total axial force on the shaft smaller, the helix directions of the two pairs of gears should be opposite. The structure is more complicated, and it is often used in places with high power and variable loads.
- Coaxial type: The axial size of the reducer is larger, the intermediate shaft is longer, and the rigidity is poor. When the oil immersion depths of the two large gears are similar, the load-carrying capacity of the high-speed gears cannot be fully utilized. Often used in places where the input and output shafts are coaxial.
- Single-stage bevel gear reducer:
A single-stage bevel gear reducer is suitable for a reduction ratio of 2~4. The transmission ratio should not be too large to reduce the size of the bevel gear and facilitate processing. It is only used in transmissions where two axes intersect perpendicularly.
- Cone and cylindrical gear reducer:
Conical and cylindrical gear reducers are suitable for reduction ratios of 8-15. Bevel gears should be arranged in a high-speed stage to reduce the size of bevel gears. Bevel gears can be straight or curved teeth. Cylindrical gears are mostly helical teeth, which can offset part of the axial force of bevel gears.
- Worm reducer:
There are mainly cylindrical worm reducers, arc toroidal worm reducers, conical worm reducers, and worm-gear reducers, among which cylindrical worm reducers are the most used.
Worm reducer is suitable for a reduction ratio of 10~80. The structure is compact, the transmission ratio is large, but the transmission efficiency is low, and it is suitable for the occasions of small power and gap work. When the peripheral speed of the worm is V≤4~5m/s, the worm is under-mounted, and the lubrication and cooling conditions are better; when V≥4~5m/s, the agitation loss of the oil is larger, and the worm is generally the upper-mounted type.
- Planetary gear reducer:
Due to the structure of the planetary reducer, the minimum single-stage reduction is 3, and the maximum generally does not exceed 10. The common reduction ratio is 3/4/5/6/8/10, and the number of stages of the reducer generally does not exceed 3, but some are large. The reduction ratio custom reducer has 4 levels of reduction.
Compared with other reducers, planetary reducers have high rigidity, high precision (single-stage can be within 1 minute), high transmission efficiency (single-stage 97%-98%), high torque, volume ratio, lifetime maintenance-free, etc. Features. Because of these characteristics, planetary reducers are mostly installed on stepper motors and servo motors to reduce speed, increase torque, and match inertia.