1. 1, main types and characteristics of reducers.

The reducer is an independent component consisting of gear transmission, worm transmission or gear-worm transmission enclosed in a rigid shell, and is often used as a transmission device for reducing speed between power machinery and working machinery. In a few cases, it is also used as a transmission device to improve speed, which is called a speed increaser at this time. Reducer is widely used in modern mechanical measurement because of its compact structure, high efficiency, accurate and reliable motion transmission, simple use and maintenance, and mass production.

There are many types of reducers, which are mainly divided into single-stage, two-stage and multi-stage according to the transmission series; According to the type of transmission parts, it can be divided into: gear, worm, gear-worm, worm wheel and so on.

1. 1. 1 cylindrical gear reducer

When the transmission ratio is below 8, a single-stage cylindrical gear reducer can be used. When it is greater than 8, it is best to choose Grade II (I = 8-40) and Grade II or above (I >；); 40) reducer. If the transmission ratio of single-stage reducer is too large, its outline size will be very large. Cylindrical gear reducers with two or more stages have several transmission arrangements, such as expansion, split and coaxial. The expansion type is the simplest, but because the bearings on both sides of the gear are not symmetrically arranged, the load will be unevenly distributed along the tooth width and the bearing capacity of the shafts on both sides will be unequal. Therefore, when designing this kind of reducer, it should be noted that the stiffness of 1) shaft is larger; 2) Torque should be input from the shaft end far away from the gear to reduce the uneven distribution of load along the tooth width; 3) The helical gear arrangement is adopted, and the low-speed stage with large load is located in the middle of the two bearings, so the distribution of load along the tooth width is obviously better than that of expansion joint. The high-speed gear of this reducer often adopts helical teeth, one side is left-handed and the other side is right-handed, and the axial forces can cancel each other out. In order to make the left and right paired helical gears automatically adjust to transmit equal load, the lighter axle should be able to move a little in the axial direction. The input shaft and output shaft of the coaxial reducer are located on the same axis, so the length of the box is short. However, the axial dimension of this reducer is very large.

Cylindrical gear reducers are widely used in all reducers. Its power transmission range can be as small as 40 000kW, its peripheral speed can also be as low as 60m/s-70m/s, and even as high as 65 438+050m/s ... The reducer with high transmission power is better to adopt double drive or center drive. These two arrangements can share the load by two pairs of gear pairs, which is beneficial to improve the stress situation and reduce the transmission size design.

Keywords: reducer rigid parts scheme