Design and Analysis of One Way Clutch and Keyless Locking Assembly

Abstract

One way clutch is used for transmitting torque in one direction while running free in the reverse. Various design configurations of One way clutches like Centrifugal Lift off Sprag and Roller type are widely used in the industries. They are used to transmit the torque in one direction due to wedging action developed at contact regions. It can also be used as holdback device as keeping the outer race fixed and inner race rotating or vice-versa. During working of the clutch, contact stresses are developed in inner/outer races. These contact stresses are considered to be very crucial in the design of clutch in order to transmit the required torque without slippage or failure of any part. This dissertation focuses on design and optimize various parameters of One way clutch in such a way to limit the contact stresses within the permissible limit of the material. The Finite Element Analysis tools has been used to verify the theoretical values of contact stresses. Keyway preparation is one of the difficult machining operations as high production cost due to various operations involved. The stress concentration developed during the process of keyway generation in shaft/hub can be fatal for variable loading of the components. If there is a directional deviation in keyway width during machining (i.e. the keyway axis is not parallel to the axis of the shaft), it will also result in non-uniform loading of the key during operation. Due to all these reasons, an alternative solution like Keyless transmission is getting popular in industries. Keyless transmission element entirely eliminates the disadvantages of the key transmission. They also provide completely tight fit around shaft without backlash. The second issue addressed by this dissertation is to find out most influencing parameters in the design of Keyless couplings and incorporate them in design to ensure the required interference fit must be developed in order to perform its basic function of torque transmission without slippage. The dissertation also focuses on evaluation of contact pressures analytically using existing design approaches and the same is to be verified using CAE tools.