Ball-Track Shaft Coupling for Fast Switching and High Torque
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Solution Overview
Problem
Existing shaft couplings face challenges in achieving quick switching times and accommodating large differences in rotational speeds due to the large angular distance between ball tracks, which also restricts torque transmission and increases noise-vibration-harshness (NVH) issues.
Innovation Solution
The proposed shaft coupling design features a reduced angular distance between ball tracks by utilizing first and second sections with differently sized end faces and chamfers, allowing for easier ball alignment and reduced switching times while maintaining high torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the angular distance between ball tracks is reduced to shorten switching time, then switching time is improved, but torque transmission capability deteriorates
Solution Approach 1:
The shaft coupling is divided into multiple independent ball tracks arranged at optimized angular distances. Each ball track operates independently to transmit torque, allowing the system to maintain high torque capacity even with reduced angular distance between tracks. The segmentation enables parallel torque transmission paths that compensate for the reduced angular spacing.
Solution Approach 2:
The invention transitions from relying solely on angular distance for torque transmission to utilizing the radial dimension as well. By optimizing the radial positioning and diameter of ball tracks, the system achieves high torque capacity with smaller angular separations. The torque transmission is distributed across multiple dimensions (angular and radial) rather than depending primarily on angular distance.
2Ease of operation
If the inlet opening of ball tracks is increased to facilitate switching, then ease of operation is improved, but NVH behavior deteriorates due to greater ball play
Solution Approach 1:
The ball tracks feature localized quality variations: the inlet regions have larger openings to facilitate easy ball entry during switching, while the running regions have precisely controlled dimensions to minimize ball play. This local differentiation allows the system to achieve both easy operation and good NVH behavior by optimizing different regions for different functions.
Solution Approach 2:
The ball tracks are designed with pre-formed inlet openings of optimized size that prepare the balls for smooth transition into the tracking path. The preliminary geometry of the inlet region guides the balls into proper alignment and position before they enter the main ball track, reducing the need for large openings while still facilitating easy switching.
3Speed
If the number of ball tracks is increased to reduce angular distance, then switching speed is improved, but device complexity increases
Solution Approach 1:
Each ball track is designed as a universal component that serves multiple functions: torque transmission, guiding ball movement during switching, and providing structural support. The standardized, multi-functional design of each ball track reduces overall system complexity despite having multiple tracks, as each component can be manufactured and assembled using the same processes and principles.
Data Source
AI summary
A shaft coupling for the switchable connection of a first shaft to a second shaft arranged coaxially thereto, comprises the first shaft, which has on a circumferential surface a plurality of first ball tracks extending along an axis of rotation over at least a first section and a second section, the first ball tracks being arranged spaced apart from one another along a circumferential direction in the first section by first webs and in the second section by second webs, as well as a plurality of first balls arranged in the first section and a plurality of second balls arranged in the second section.