| Transient elastohydrodynamic lubrication (EHL) of involute helical gears has been studied in this thesis, including three parts, i.e., inverted the actual helical gears in mesh into an calculate model; isothermal EHL of helical gears and thermal EHL of helical gears.In the first part, analyzed the involute helical gear's geometrical parameters and characters in detail. Utilized the helical line's character of helical gear teeth, the connection between pressureangle of involute and unwindedeagle of involute, then received the calculate equations that can invert actual helical gears' meshing parameters at either location into two inverse tapered rollers' geometrical parameters. Assumed that the load is average distributed on the total contact line, and calculated the ratio of load on the currently meshing teeth using FORTRAN program.Based on the first part, investigated the isothermal EHL problem of a pair of meshing helical gears' teeth at either location. Utilized the corresponding connection between pressure line and contact line, analyzed the transient characters of the distributions of pressure and film thickness at either location, also analyzed the transient changes of pressure and film thickness along the pressure line. The numerical results show that, it is available to use two inverse tapered rollers' EHL simulate involute helical gears' EHL. But part of the longest contact line's EHL could not figure other location's EHL which has the same length of contact line.The third part of this thesis calculated and analyzed the thermal EHL problem of a pair of meshing helical gears' teeth at either location. Compared with the isothermal EHL, analyzed the transient characters of the distributions of pressure, film thickness and temperature at either location. The numerical results show that, because of the effect of temperature, the pressure of the film is bigger, the thickness is smaller; the second pressure peak is higher, and the degree of film's shrinking is bigger. |
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