The Method of Calculating the Thickness of the Oil Film between the Teeth of Closed Cylindrical Gears

The purpose of the work is to obtain patterns of changes in the thickness of the oil film in cylindrical gears depending on the dynamic viscosity of the oil; the total rolling speed, the sliding speed of the teeth, and the contact pressure in the gears during friction.

Cylindrical gears of a closed type operating in transmission oil at contact stresses not exceeding 2500 MPa and at an oil temperature of not more than 150 °C. were studied.

A method for calculating the thickness of the oil film is proposed, taking into account the sliding speed between the contacting surfaces of gears; as well as the sequence of calculating the total thickness of the oil film, taking into account contact deformations, the value of which depends on changes in the hydrodynamic properties of the oil during friction. The results of a study of the factors influencing the thickness of the oil film between the friction surfaces of the teeth at a total rolling speed of 6.12 m/s have been obtained. The sliding speed range is 1.0—3.0 m/s, the contact pressure is 186.9—457.9 MPa, and the dynamic viscosity of transmission oil is 17.44—24.24 MPa/s. The calculated values of the oil film thickness vary widely from 0.97×10^–6 m to 2.06×10^–6 m, patterns of changes in the thickness of the oil film are obtained from: dynamic oil viscosity at a constant value of the total rolling speed and contact pressure; rolling speeds in the presence of slippage between the gears.

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