Rotary Drive Design With Conical Centering Surfaces
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Solution Overview
Problem
Existing rotary drive designs experience misalignment between the tool and workpiece due to gaps caused by manufacturing tolerances, leading to transverse forces and inefficient torque transmission.
Innovation Solution
A rotary drive design featuring a cylindrical basic shape with alternating projections and recesses, accompanied by conical surfaces that deviate from a common cone axis, optimizing surface area for torque transmission while maintaining centering capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a basic cylindrical shape with alternating projections and recesses is used, then manufacturing is simplified, but gaps occur between the tool and workpiece due to manufacturing tolerances
Solution Approach 1:
The rotary drive configuration is segmented into multiple functional surfaces: cylindrical basic shape for torque transmission and conical centering surfaces for alignment. This segmentation allows each surface to be optimized for its specific function while maintaining overall manufacturing simplicity.
Solution Approach 2:
Conical centering surfaces are introduced as intermediary elements between the cylindrical torque-transmitting surfaces. These conical surfaces act as mediators that eliminate gaps and ensure precise alignment between tool and workpiece axes before torque transmission begins.
2Manufacturing precision
If conical surfaces are added for centering, then alignment precision improves, but the surface area for torque transmission decreases
Solution Approach 1:
Different regions of the rotary drive configuration are assigned different qualities: cylindrical surfaces provide torque transmission area while conical surfaces provide centering function. The conical surfaces are positioned locally between the cylindrical sections, optimizing each local region for its specific function.
3Manufacturing precision
If the conical surfaces are made larger for better centering, then centering precision improves, but the torque transmission area is further reduced
Solution Approach 1:
The geometry parameters of the conical surfaces are optimized: the cone angle is set between 5° and 15°, and the axial extent corresponds approximately to the depth of the drive recess. These parameter changes ensure sufficient centering precision while minimizing the impact on torque transmission area.
Data Source
Figure 1~3
Figure 4~6
Figure 7~11
AI summary
The invention relates to a design for a rotary drive for both a tool and a workpiece to be rotationally driven. Said rotary drive design includes a basic cylindrical shape that deviates from a circular cylindrical shape. The contour or the cross-section through said basic shape has multiple rounded protrusions (3, 17) and rounded recesses (4, 18) lying between said protrusions. The protrusions tangentially approximate a circle with a maximal radius (5), while the recesses tangentially approximate a circle with a minimal radius (7). Conical surfaces (8, 19) are formed in the regions between the protrusions in a manner deviating from said basic cylindrical shape, said conical surfaces not cooperating in the transmission of torques but allowing the tool and the workpiece to be centered and aligned in relation to one another.