Kinematic Design On An Axial/Radial Telescopic Tire Building Drum With Big Telescopic Ratio

The tire building drum is an important part of the tire building equipment, and aircraft tire building drum is an axial/radial telescopic mechanism used to build aircraft tire. Based on the demand for independent innovation of Chinese aircraft tire building drum, and aiming at an axial/radial telescopic tire building drum with big telescopic ratio, a research has been done on calculation of degree of freedom, analysis of the kinematic characteristic, dimension synthesis, virtual prototype and motion simulation, etc. The main contents and achievements are as follows:Based on the screw theory and corrected G-K criterion, redundant constraints and degrees of freedom are analyzed and calculated using the substructure method, and a conclusion is finally obtained that the mechanism is a multi-over-constrained mechanism possessing four driving degrees of freedom and twelve partial degrees of freedom. The analyzing method provides references for mobility analysis of various complicated multi-loop spatial mechanisms.The role of the groove cam is analyzed and the configuration innovation hereby is performed. Configurations of two sets of internal slab linkages lead out the two layers of tire building drum, whose differences from the three layers of tire building drum are shown. The analyzing method provides a new idea for configuration innovation of building drums with higher pair mechanisms.Dimensionless analysis method is used to analyze movement rule of the key components such as drum shoulders, main and articulated connecting rods, etc. Relative movement of three drum shoulders is studied in the direction of axial, radial and circumferential directions respectively. The research lays an important theoretical foundation for dimension synthesis of the mechanism.Based on the substructure method, the mechanism is decomposed into the innermost linkage, the intermediate linkage, the outermost linkage and the groove cam, whose dimensions are designed respectively. The innermost and intermediate linkages are all trajectory generation problems with two accurate points, and the outermost linkage is a rigid body guidance problem with three positions. Profile of the groove cam is designed base on the method of transformation of coordinates.On the base of the result of dimension synthesis, the three-dimensional model and motion simulation is accomplished using the software of Solid Works, which verifies the correctness of the design method.