The gear reducer is generally used for low-speed, high-torque transmission equipment, the motor, internal combustion engine or other high-speed power, through the input shaft of the reducer gears with fewer teeth mesh with the output shaft of the large gear to achieve the purpose of deceleration, the ratio of the number of teeth of large and small gears, is the transmission ratio.

Reducer is a relatively precise machinery, the purpose of using it is to reduce the speed and increase the torque. There are many types of reducers with different models, and different types have different uses.

According to the type of transmission can be divided into gear reducer, worm gear reducer and planetary gear reducer; according to the number of transmission stages can be divided into single-stage and multi-stage reducer; according to the shape of the gear can be divided into cylindrical gear reducer, bevel gear reducer and bevel-cylindrical gear reducer; according to the form of transmission arrangement can be divided into unfolded, shunt type and coaxial reducer.

In order to facilitate the reasonable selection of reducers, several common reducer types, characteristics and applications are listed for reference when selecting the model.

Single-stage cylindrical gear reducer is suitable for reduction ratio 3~5. The gear teeth can be straight, helical or herringbone teeth, and the box is usually cast in cast iron or welded with steel plate. Bearings are commonly used rolling bearings, only when the heavy load or special high-speed use sliding bearings.

The two-stage cylindrical gear reducer is divided into three types: spread type, split type and coaxial type, and the applicable reduction ratio is 8~40.

Spread type: High-speed stage with long-tailed helical gears, low-speed stage can be straight or helical gears. Due to the asymmetric arrangement of the gears relative to the bearings, the shaft stiffness is required to be larger and the torque input and output ends are kept away from the gears to reduce the uneven distribution of load along the tooth width caused by the bending deformation of the shaft. Simple structure and most widely used.

Shunt type: High-speed stage shunt is generally used. Since the gears are symmetrically arranged relative to the bearings, the gears and shafts are subjected to more uniform forces. In order to make the total axial force on the shaft smaller, the helix direction of the two pairs of gears should be opposite. The structure is more complex and is commonly used in high power and variable load locations.

Coaxial type: The axial size of the reducer is larger, the intermediate shaft is longer, and the stiffness is poorer. When the two large gears are immersed in similar oil depth, the load-bearing capacity of the high-speed gear cannot be fully developed. It is commonly used in the place where the input and output shafts are coaxial.

Single-stage bevel gear reducer is suitable for reduction ratio 2~4. The transmission ratio should not be too large in order to reduce the size of bevel gear and facilitate processing. Only used in the transmission where the two axes intersect vertically.

The bevel and cylindrical gear reducer is suitable for reduction ratio of 8~15. The bevel gear should be arranged in high speed stage to reduce the size of bevel gear. Bevel gears can be straight or curved teeth. Cylindrical gears are mostly helical teeth, so that they can offset part of the axial force with the bevel gears.

There are mainly cylindrical worm gear reducer, circular ring worm gear reducer, cone worm gear reducer and worm-gear reducer, among which the cylindrical worm gear reducer is most commonly used.

The worm gear reducer is suitable for the reduction ratio of 10~80. compact structure, large transmission ratio, but low transmission efficiency, suitable for small power and clearance work. When the worm circumferential speed V≤4~5m/s, the worm is of the lower type with better lubrication and cooling conditions; when V≥4~5m/s, the churning loss of oil is larger, and the worm is generally of the upper type.

Planetary reducer because of the structure, the minimum single-stage reduction of 3, the maximum generally does not exceed 10, common reduction ratio: 3/4/5/6/8/10, the number of reducer stages generally does not exceed 3, but there are some large reduction ratio custom reducer has a 4-stage reduction.