하이브리드 대형특수 기어 최적설계 및 신뢰성평가

Abstract

The gear has played the important roles for long time as the one of representative mechanical elements together with bearing and screw since the industrial society. The gear not only plays the role of transmitting the power and is widely used as the one for the wrist watches in small size and turbine reduction gear for vessel in thousands of kw class, reduction device in automobile and aircraft, differential gear and wind power generator in large size but also its kind and usage are various even today. The gear that is developed in such various ways is developed to carry out the complex operations and its research and development are carried out in various types. The gear with such complex operations, special generation and shape is called as hybrid gear and its development is being carried out by the companies and academic society actively. Some flaws are found in such hybrid gear sometimes, however, the flaw of gear that is used for transmitting power and changing the angle especially take the large portion. When it comes to gear, the internal crack is generated in case of forging process, error is done in process step and abrasion, strain and break are generated in the operation step due to the frequent friction. The flaw of gear may become the cause of damage as it generates the vibration and noise from the load and continuous collision with the counterpart gear and it plays as the factor that accelerates the fall of reliability and durability of whole system. So, the general interpretation about the gear is necessary by the necessity that the economic and high quality of gear is produced. The quantitive Infrared Thermography Test evaluation is required for the safety and lifetime extension of gear products. The ingredients of material should be grasped and the internal flaw should be monitored for manufacturing of gear product and the safety of the used gear. In case the flaw or heterogeneous material is in the gear, its existence, shape and location should be grasped because it may lower the performances and lifetime of the gear considerably. As even small damage in the operation step of the gear may cause not only the severe damage to the machine but cause big accident due to mechanical defect, the periodic diagnosis and soundness evaluation against the gear are very important. There many ways of detecting the flaw of gear. In case of ultrasonic flaw detecting test, Manual Ultrasonic Testing, Phased Array Ultrasonic Testing (PAUT) and Noncontact Ultrasonic Testing are under application currently, but they have the weakness that they are not able to detect the flaw along the shape. Infrared Thermography Test and Vibration Durability Test are suggested as the technology that can supplement such weakness. Vibration Durability Test is the method that measures and analyzes the vibration values the testing object shows in principle way. Infrared Thermography Test detects the infrared ray radiated from the testing object as the energy with infrared ray measuring device, analyzes its temperature distribution with thermogram that is mapped in image and estimates its internal status in principle way. Infrared Nondestructive Thermography Test can be classified into Passive method and Active method in large category. The Passive method is the general measuring method that detects the infrared energy naturally radiated from the testing object and Active method is the one that analyzes the infrared energy that provides the controllable energy and the testing object radiates as the response without depending on its own amount of infrared ray.