MODIFICATION OF GEOMETRY AND TECHNOLOGY OF CYLINDRICAL WORMS

The objective of this research is to develop a new method of grinding process that can efficiently make concave profile of the worm thread smooth. The grinding is carried out using a wheel with curvature profile in the axial plane in the form of an arc of logarithmic spiral. The proposed method will provide maximum line of contact between the tool and the worm with minimum stress concentration at any point. The generating equation of the grinding tool profile and its arrangement with respect to the worm during thread grinding were determined.     

ELASTOPLASTIC CONTACT BEHAVIOR AND SHAPE OPTIMIZATION OF DRILLPIPE THREAD

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用于大型轴承桃形沟修整的圆弧修整器的设计

简要介绍了一种可用于大型轴承桃形沟圆弧修整的砂轮圆弧修整器的结构和工作原理。采用双向液压缸驱动,同时采用机械和电器双限位,以保证砂轮圆弧修整的安全、准确和高效。     

SELECTION OF GEOMETRIC PARAMETERS OF GEAR AND GRINDING WHEEL TO ENSURE MAXIMUM GEAR TOOTH PROFILE ACCURACY

An analysis of possibilities for the selection of gear and tool geometry parameters is presented to reduce tooth profile errors during the grinding of gears by double tapered wheel (Hofler or Niles method), double wheel generating (Maag method) and by worm wheel techniques (Reishauer method). The selection of gear and tool geometry parameters is based on the analysis of the grid diagram of a gear and a rack. Formulas and graphs are presented for the selection of the pressure angle, module, and addendum of the rack-tool. The experimental results of the grinding of gears confirm the theoretical analysis.     

EFFECT OF SOME MODIFICATIONS TO OXLEY'S MACHINING THEORY AND THE APPLICABILITY OF DIFFERENT MATERIAL MODELS

Oxley's machining theory has recently been extended[1] to accept material property inputs in the form of widely used constitutive models such as the Johnson-Cook and MTS material models. In the process, additional modifications have been made to the model to improve its self-consistency. For instance, the shear force is obtained from the total work of deformation, thereby eliminating the unknown parameter η, and the hydrostatic pressure at the tool-chip interface is calculated considering the gradient in temperature in addition to the gradient in strain. This study is aimed at understanding the effect of these modifications separate from the changes due to the introduction of the new material models by comparing results obtained using Oxley's original model to that obtained with the above modifications. We also compare results obtained using different constitutive models for AISI 1045 to the experimental results of the “Assessment of Machining Models” effort.     

EFFECT OF SOME MODIFICATIONS TO OXLEY'S MACHINING THEORY AND THE APPLICABILITY OF DIFFERENT MATERIAL MODELS

Oxley's machining theory has recently been extended[1] Adibi-Sedeh, A. H., Madhavan, V. and Bahr, B. 2002. Extension of Oxley's analysis of machining to use different material models. Submitted to ASME Journal of Manufacturing Science and Engineering [Google Scholar] to accept material property inputs in the form of widely used constitutive models such as the Johnson–Cook and MTS material models. In the process, additional modifications have been made to the model to improve its self-consistency. For instance, the shear force is obtained from the total work of deformation, thereby eliminating the unknown parameter η, and the hydrostatic pressure at the tool-chip interface is calculated considering the gradient in temperature in addition to the gradient in strain. This study is aimed at understanding the effect of these modifications separate from the changes due to the introduction of the new material models by comparing results obtained using Oxley's original model to that obtained with the above modifications. We also compare results obtained using different constitutive models for AISI 1045 to the experimental results of the “Assessment of Machining Models” effort.