Torque-Locked Shaft-Hub Connection with Continuous Thread
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Solution Overview
Problem
Existing shaft-hub connections require large diameter differences for torque transmission, leading to unnecessary space and weight, particularly in motor vehicle chassis where external threads are needed, resulting in poor mechanical properties and increased costs due to oversized eccentric screws.
Innovation Solution
A torque-locking connection using sector-shaped profiles on the shaft and hub, where the profile is designed with recesses and protuberances forming a convex lens cross-section, allowing for uninterrupted external threads and reduced diameter differences, enabling efficient torque transmission with self-centering capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a large diameter difference is used between the shaft profile and the external thread, then torque transmission capability is improved, but weight and space consumption increase significantly
Solution Approach 1:
The invention changes the geometric parameters of the shaft profile by using sector-shaped indentations with specific angular ranges (30° to 90°) and depth ratios (0.2 to 0.8 of the radius), enabling effective torque transmission with minimal diameter difference between the profile and external thread
Solution Approach 2:
The sector-shaped indentations utilize curved geometric forms with defined radii and angular sectors, creating an optimized profile geometry that transmits torque efficiently while minimizing the diameter difference and resulting weight reduction
2Force
If a large diameter difference is used between the shaft profile and the external thread, then torque transmission capability is improved, but the eccentric screw becomes thicker and more expensive
Solution Approach 1:
By optimizing the angular sector range (30° to 90°) and depth ratio (0.2 to 0.8 of radius) of the indentations, the invention achieves sufficient torque transmission with minimal profile diameter, reducing the overall thickness and complexity of the eccentric screw component
Solution Approach 2:
The curved sector-shaped profile geometry provides optimal torque transmission surface area within a compact diameter, eliminating the need for excessive thickness while maintaining structural integrity and reducing manufacturing complexity
3Shape
If interrupted external threads are used to accommodate the profile, then the profile can be formed, but mechanical properties are significantly impaired and thread destruction risk increases
Solution Approach 1:
The torque transmission function is segmented from the external thread by using sector-shaped indentations that are radially offset from the thread, allowing the thread to remain continuous and unbroken while the indentations provide the necessary profile for torque transmission
Solution Approach 2:
The profile features are positioned in a different radial dimension than the external thread, with the deepest point of the indentation radially offset from the thread diameter, enabling both continuous threading and effective torque transmission without interference
4Force
If the profile deepest point is at or above the thread diameter, then torque transmission is maximized, but the hub part cannot be assembled over the thread
Solution Approach 1:
The invention optimizes the angular sector range (30° to 90°) and depth ratio (0.2 to 0.8 of radius) to create sufficient torque transmission surface area while keeping the radial depth limited, enabling both effective torque transmission and clearance for thread passage
Solution Approach 2:
The curved sector-shaped indentations with defined radii create an optimized profile that provides adequate torque transmission surface while maintaining a compact radial depth that allows the hub part to clear the external thread during assembly
Data Source
Figure 1
Figure 2a~2b
Figure 3a~4
AI summary
A torque-locked connection between a hub or disk (14) and a shaft, a journal or a shank (12), wherein the hub or disk (14) is provided with a profiled passage for the shaft, the journal or the shank (12) and said shaft, journal or shank in turn is provided with a corresponding outside profile (16) and an outside thread (26) following said outside profile (16), said outside thread being used to screw on a nut so as to secure the hub or disk (14), wherein the difference between the outside diameter of the outside thread (26) and the outer surrounding diameter of the profile (16) is no more than 1 mm.