Vibration monitoring of gear transmission Niola V., Quaremba G., Avagliano V. Department of Mechanical Engineering for Energetics University of Naples “Federico II” Via Claudio 21, 80125, Napoli, ITALY vincenzo.niola@unina.it http://niola.dime.unina.it/ Abstract – The paper shows an analysis carry out on a gear transmission through the test-rig. Our attention will be focused on the duration test and how to stop it if an unexpected event occurs. In the first part it is described the duration test assessment performed on the gear transmission. In the second part it is showed the set up of the gear transmission test and the selection of the right points for the measurement and the equipment used for the assessment. In the third part it is showed the algorithm for monitoring the test. The aim of the algorithm is to assure the test will be stopped if the gear transmission will be damaged for any reason. This algorithm, by detecting early the gear crack, gives us the advantage of assuring the integrity of the gear transmission and consequently the possibility of inspecting it. Key-Words: - Gear transmission, Fourier Analysis, Pitting, Side Bands. 1 Introduction Measurement and analysis of vibration, in order to monitor the operating condition of industrial equipment during their operation, had a great development during the last 30 years. The vibration analysis is now employed in many fields: from steel factories to petrochemical ones, from mechanical industries to the aviation and aerospace applications. The measurement of vibrations performed on a generic machine during its working process contains many information on the working condition. Usually, each process set up or inner mechanical changing show a characteristic vibrational pattern; a significative changing of this pattern should be reveal the presence of some anomalies in the system. The theoretical basis of the algorithm, object of this paper, is based on the knowledge that the vibrational signal processing performed by means of the spectral analysis obtained by the accelerometer is the most efficient technique for monitoring cars gear transmission; in fact, by monitoring the spectrum signal, we analyze the temporal evolution of characteristic frequencies of the gear transmission components. With this technique it is possible to detect such anomalies. In fact, every gear transmission has a characteristic frequency spectrum but the presence of defects may change this inner spectrum in several ones depending on the type of defect itself. It is well known that before the production and commercialization of a new engineered gear transmission it is necessary to assess many reliability tests. One of these concerns its duration. 2 The duration test assessment The duration test is made only after that the gear transmission has overthrew the lubrication test. Therefore is done a running in for all the gears. During this phase the gear transmission works in a low rotation velocity (2000 – 2500 rpm) with low value of torque (approximately the 10% of the maximum torque). When this phase is over, and after the substitution of the lubricating oil, it can starts the reliability test (duration test). This test consists of a run of the gear transmission for a huge number of kilometres in all gears, both in condition of maximum torque and in condition of maximum rotation velocity. The maximum torque and power, and the relative rotation velocity, are sets on the basis of the features of engine and on the gear ones. This example shows the test for only one gear, because the test is the same for all gears. It is chosen the first gear. The total distance that gear transmission must drive is established: the total distance that the gear transmission must drive in first gear is indicated by . This distance isn’t driven in only one step, but in steps of equal length 1 D N 1 1 d D N = . The value chosen for N is 100, so if a gear transmission doesn’t show any imperfection after 100 steps, it says that it has achieved the 100% of the test. Proceedings of the 9th WSEAS International Conference on SIMULATION, MODELLING AND OPTIMIZATION ISSN: 1790-2769 74 ISBN: 978-960-474-113-7