The Zero-backlash Double-roller Enveloping Hourglass Worm Gear's Contact Analysis

After analysis and research of various worm gears, a new kind of zero-backlash worm gear sets, named double-roller enveloping hourglass worm gear , is proposed by Professor Wang Jing-ge. It is applied for the realization of worm-drive with high precision, high efficiency and long life-span of precision in now mechanical transmission field. Zero-backlash double-roller enveloping hourglass worm gear is a kind of special form of the new worm-drive, it's design and machining are investigated in this paper. This paper investigates the meshing theory, geometry parameter design, structure design, construct three-dimensional solid model and finite element analysis. The content of this research is as follows:According to the theories of differential geometry and gear meshing, a perfect set of meshing system of the double-roller enveloping hourglass worm gear in an ideal situation is established by applying kinematics method. We deduced the meshing function of this drive and worm tooth surface equations. And, the formulas of contacting parameters which include induced normal curvature, lubrication angle and rotation angle are derived.According to geometry parameters design of the worm gear, geometry features of the worm is derived with the aid of engineering software such as Matlab. Three-dimensional solid model and the zero-backlash double-roller enveloping hourglass worm gear are constructed with the aid of Pro/E. Using the interface between ANSYS and Pro/E, geometry model of the zero-backlash double-roller enveloping hourglass worm gear which is constructed with Por/E is translated into ANSYS,contact infinite element model of the worm gear have been constructed.We investigated the load share between gear teeth, stress distribution on contacting-line and strength with the aid of ANSYS, mises stress nephogram and distortion nephogram are derived. All of these works proved strength to satisfy requirement of the design.Finally,we studied the worm gear model with installations error used finite element analysis,and acquired mises stress nephogram.Through comparative analysis between ideal mises stress nephogram and actual mises stress nephogram,we can find which factor has greatest impact on worm gear's drive.It has important guide on actual installations.