UNIT-II updated.ppt
- 2. TORSION • Torsion of shafts refers to the twisting or rotational deformation experienced by a long, slender cylindrical component known as a shaft when subjected to a torque or twisting force. • This twisting results in the shaft's cross-sectional elements undergoing angular displacement relative to each other.
- 12. POWER TRANSMITTED BY SHAFT
- 15. SPRINGS Springs are the elastic bodies which absorb energy due to resilience. The absorbed energy may be released as and when required. A spring which is capable of absorbing the greatest amount of energy for the given stress, without getting permanently distorted, is known as the best spring. The two important types of springs are: 1.Laminatedor leaf springs and 2. Helical springs. Laminated or leaf spring. The laminated springs are used to absorb shocks in railway wagons, coaches and road vehicles (such as cars, lorries etc.).
- 16. HELICAL SPRINGS • Helical springs are the thick spring wires coiled into a helix. They are of two types: 1. Close-coiled helical springs and 2. Open coiled helical springs. • Close-coiled helical springs. Close-coiled helical springs are the springs in which helix angle is very small or in other words the pitch between two adjacent turns is small. A close-coiled helical spring carrying an axial load is shown in Fig. As the helix angle in case of close-coiled helical springs are small, hence the bending effect on the spring is ignored and we assume that the coils of a close-coiled helical springs are to stand purely torsional stresses.
- 17. Helical springs
- 19. Closed coil helical spring Open coil helical spring Wire of the close coiled helical spring is wound tightly providing no gap between two adjacent coils of the spring. Wire of the open coiled helical spring is wound not so tightly and thus sufficient space or gap exists between two adjacent coils. Pitch of spring wire is smaller due to small helix angle. Pitch of spring wire is comparatively larger as a result of larger helix angle Close coiled springs cannot undergo axial compression. It is designed to resist stretching and twisting. Open coiled springs are designed to undergo extension and compression; and deflect its length accordingly under the action of axial load. The close-coiled spring is a torsion spring and the bending stress is negligible. open-coiled helical springs belong to the categories of torsion and bending springs
- 22. The spring index is defined as the ratio of the mean diameter of the coil to the diameter of the wire c=D/d
- 23. The solid length of the spring means the distance between the coils when the coils are touching each other. There is no gap between the coils. The solid length is given by Solid length =Number of coils x Dia. of wire = nx d