In this paper, the complex problem of deflection of loaded spur teeth cut in thin rims is studied.Tooth-deflection curves, modified for the effect of elasticity of the gear, and rim stiffness factors are introduced.

The problem of involute helical gear noise is studied by running a pair of 6 DP gears in a power circulating rig inside an anechoic room. More than 3500 magnetic tape recordings were taken and analyzed, for gears running at different speeds and transmitting different loads. A pair of 14 DP nickel steel gears of finished, ground, and shaved teeth was also tested to study the effect of surface finish on gear noise. Experimental results revealed that the main sources of gear noise are impact between gear teeth and friction. A sudden rise in noise level has been noticed when a whole number of teeth are in contact. This paper presents experimental results and study of noise of involute helical gears of different facewidths and pitches, running at different speeds, and transmitting different loads. The source of gear noise and noise generating mechanisms are also discussed.

The paper presents results of strain gage investigations conducted on steel spur gears to measure the instantaneous load on the tooth under static and dynamic conditions.

THE UNE OF CJNr>JCT Fig. 12 Static relative displacements at different angular positions TFLOTH MO 2 IH MTSH ' TJM" MH' txKM of ioao Fig. 13 Maximum dynamic increments at different speeds and static loads 3 Effect of torsional vibrations and dynamic unbalance on dynamic loading. 4 Effect of cyclic variation of the externally applied load on the dynamic loading.

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fcj), = spur gear tooth stiffness along line of action, lb/in. F = face width, in. h -effective tooth height, in. I = effective tooth thickness, in. E ~ modulus of elasticity, psi k' = stiffness per in. of face (approximately = 2 X 10 6 lb/in. /in. for test gear)

The paper presents the results of an experimental investigation carried out at Mansoura University Laboratories aiming at studying the effect of change of speed, oil viscosity, and helix angle on the load carrying capacity of the oil film. A three pairs of test gears of 6 DP, 91.5 mm pitch diameter with 22.3, 33.6 and 42.25 deg helix angles were run in power circulating test rig at 100 to 3000 r.p.m. speeds and transmitting tooth load ranging from 185 to 1090 Kp. The test gears were lubricated with oils of 200, 462, and 653 cSt at 40°C kinematic viscosities. The oil film thicknesses between contacting teeth were measured by measuring the changes in capacitance between test gears and transferred to linear dimensions by calibration curves drawn by knowing the changes in capacitance through the gaps between teeth of values known through the amount of backlash. The experimental results show that; Oil film thickness decreases with tooth load, while increases with speed and viscosity of the lubricant. Oil film thickness versus helix angle give an inversed parabola for the smallest and medium tooth loads, while oil film thickness decreases with increasing the helix angle under increased tooth loads. Load carrying capacity increases with speeds and viscosity of the lubricant while decreases with increasing the helix angle.

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