Research On Torgue Transmission Characteristics Of The Composite Hub Connection Under Heavy Load

Shaft-hub connection is used to realize the fixation of shafts and the parts on them and is an essential section in mechanical transmission. Interference fit and flat key are the two most common forms of connection and torque transmission. Single connection mode is simple in structure but has many problems in usage especially under heavy load. For interference fit, skidding happens when there is not enough magnitude of interference while stress concentration happens when the magnitude is too large. For flat key, severe abrasion happens when it suffers alternate and impulsive loads and it would deform to failure under heavy load. Besides, single flat key connection cannot bear axial load. There are descriptions of the mode of composite connection combining interference fit and flat key connection in the Mechanical Design Manual but there are no further researches on the accurate distribution of the outer torque between the two kinds of connection. The application of this kind of composite connection in reality also set the parameter on the basis that each mode of connection can take full charge which would increase the safety coefficient but would waste materials and lead to structural redundancy.On the basis of the analysis of the Research status at home and abroad, this thesis built the model of composite shaft-hub connection and studied the torque allocation between the two kinds of connection. The stresses and their distribution were studied on the contact surfaces between the shaft and the hub and also the surfaces between the side surfaces of the key and the key slot. The effect of the fit state of key and slot on the allocation was also studied. The laws of effect of the magnitude of interference and the length of the key were analyzed by the control variable method. The Mathematical Model with the magnitude of interference and the length of the key as Adjustable parameters and the maximum stress and the torque allocation as target parameters was built to guide the design of composite shaft-hub connection under different working conditions.