How big is the maximum two stage retarder?
There are two major categories of cylindrical gear reducer, namely, involute tooth profile and circular arc tooth profile. In addition to the gear profile, the reducer structure is basically the same. While the transmission power and transmission ratio are the same, the size of the gear reducer in the length direction is about 30% than that of the involute gear reducer.
The cylindrical gear reducer is the most widely used in all reducers. It can transfer power from small to 40 000kW, the circumferential velocity can also be from a low to a 60m/s 70m / s, even up to 150m / s. The reducer with large transmission power is best to use dual drive or central drive. The two kinds of arrangement can be shared by two pairs of gear pairs, which is beneficial to improve the force condition and reduce the transmission size. In the design of double drive or center driven gear drive, automatic balancing device should be adopted to make the load of gear pair be evenly distributed, for example, sliding bearing and elastic support.
When the transmission ratio is below 8, a single stage cylindrical gear reducer can be used. Greater than 8, it is best to use two (i=8 - 40) and more than two (i>40) of the reducer. Single stage reducer transmission ratio is too large, the overall size will be great. The gear arrangement of gear reducer with two or more than two grades has expansion, split flow and coaxial type. The expansion type is the simplest, but because the bearings on both sides of the gear are not symmetrically arranged, the load is unevenly distributed along the width of the teeth, and the bearing capacity of the shafts on both sides is unequal. Therefore, should pay attention to in the design of the reducer: 1) shaft stiffness should be larger; 2) input torque should be far from the gear shaft, in order to reduce the uneven distribution of load along the tooth width; 3) using helical gear arrangement, and the loading of large low level and is located just two bearing the middle, so the load distribution along the tooth width obviously than the good start. The high speed gear of this reducer usually adopts oblique teeth, the left side of the gear is one side, the other side is right, and the axial forces can cancel each other. In order to make about two of the gear can be automatically adjusted to equal the load transfer, the lighter axle should be able to do a small walk in the axial direction. The input shaft and the output shaft of the coaxial reducer are on the same axis, so the length of the case is shorter. But the reducer has larger axial dimensions.
