tailieunhanh - Text Book of Machine Design P22

CONTENTS CONTENTS 776 C H A P T E R n A Textbook of Machine Design .lywheel 22 1. Introduction. 2. Coefficient of Fluctuation of Speed. 3. Fluctuation of Energy. 4. Maximum Fluctuation of Energy. 5. Coefficient of Fluctuation of Energy. 6. Energy Stored in a Flywheel. 7. Stresses in a Flywheel Rim. 8. Stresses in Flywheel Arms. 9. Design of Flywheel Arms. 10. Design of Shaft, Hub and Key. 11. Construction of Flywheel. Introduction Introduction A flywheel used in machines serves as a reservior which stores energy during the period when the supply of energy is more than the requirement and releases it during the period when. | CONTENTS C H A P T E R 22 Flywheel 1. Introduction. 2. Coefficient of Fluctuation of Speed. 3. Fluctuation of Energy. 4. Maximum Fluctuation of Energy. 5. Coefficient of Fluctuation of Energy. 6. Energy Stored in a Flywheel. 7. Stresses in a Flywheel Rim. 8. Stresses in Flywheel Arms. 9. Design of Flywheel Arms. 10. Design of Shaft Hub and Key. 11. Construction of Flywheel. Introduction A flywheel used in machines serves as a reservior which stores energy during the period when the supply of energy is more than the requirement and releases it during the period when the requirement of energy is more than supply. In case of steam engines internal combustion engines reciprocating compressors and pumps the energy is developed during one stroke and the engine is to run for the whole cycle on the energy produced during this one stroke. For example in . engines the energy is developed only during power stroke which is much more than the engine load and no energy is being developed during suction compression and exhaust strokes in case of four stroke engines and during compression in case of two stroke engines. The excess energy developed during power stroke is absorbed by the flywheel and releases it to the crankshaft during other strokes in which no energy is developed thus 776 CONTENTS Flywheel 777 rotating the crankshaft at a uniform speed. A little consideration will show that when the flywheel absorbs energy its speed increases and when it releases the speed decreases. Hence a flywheel does not maintain a constant speed it simply reduces the fluctuation of speed. In machines where the operation is intermittent like punching machines shearing machines riveting machines crushers etc. the flywheel stores energy from the power source during the greater portion of the operating cycle and gives it up during a small period of the cycle. Thus the energy from the power source to the machines is supplied practically at a constant rate throughout the operation. Note The