Winding Shaft Core Structure for Precise Hollow-Shaft Insertion
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Solution Overview
Problem
Existing winding shaft designs face challenges with shaft cores having variable insertion depths, leading to assembly difficulties and potential damage, along with stability issues due to play between hollow shafts and shaft cores, resulting in noise and material fatigue.
Innovation Solution
A winding shaft design where the demolding direction is rotated by 90°, allowing lateral webs to form contact surfaces for the hollow shaft, enhancing rigidity and strength with freely selectable rib arrangements, and incorporating a screw-in channel for axial fixation, enabling secure insertion and torque transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the insertion pin is made conical for demoldability of injection-molded shaft cores, then the shaft cores can be easily removed from the mold, but the insertion depth of the shaft cores into the hollow shaft varies, resulting in play and assembly difficulties
Solution Approach 1:
The shaft core is divided into multiple parts: a conical insertion pin for demoldability and a cylindrical receiving portion with a clamping element for precise positioning. This segmentation allows each part to fulfill its specific function without compromise.
Solution Approach 2:
A clamping element acts as an intermediary mechanism between the conical insertion pin and the hollow shaft. It provides the necessary clamping force to secure the shaft core at a precise insertion depth, eliminating play while maintaining ease of manufacture.
2Stability of the object's composition
If the play between hollow shaft and shaft core is reduced for stability, then movement and noise are minimized, but the insertion becomes more difficult and may damage the shaft cores
Solution Approach 1:
The clamping element is designed to be movable during assembly, allowing easy insertion with play, and then movable to a clamped position to eliminate play during operation. This dynamic adjustment resolves the contradiction between ease of assembly and operational stability.
Solution Approach 2:
The conical insertion pin performs the preliminary action of guiding the shaft core into the hollow shaft with appropriate play, preparing the assembly for the subsequent clamping action that secures the precise position without damage.
3Strength
If the shaft core is made with sufficient wall thickness for stability, then structural integrity is improved, but the injection molding process is constrained by limited available wall thicknesses
Solution Approach 1:
The shaft core is segmented into the insertion pin and receiving portion, allowing different wall thicknesses in different regions. The receiving portion can have sufficient wall thickness for strength, while the insertion pin can have thinner walls suitable for injection molding.
Solution Approach 2:
Different regions of the shaft core have different wall thicknesses optimized for their specific functions. The receiving portion has greater wall thickness for structural integrity, while the insertion pin has reduced wall thickness for manufacturability, creating local quality variations.
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
A shaft core (10; 110) has an outer cross-section (20) for constructing a multi-part shaft. To ensure a secure fit in a hollow shaft with simple manufacturing, the shaft core (10) is designed as an injection-molded or die-cast part with a demolding direction perpendicular to the shaft axis, wherein the enclosing outer cross-section (20) of the shaft core (10) is at least partially formed by strip-like end faces (24) of webs (26) that are aligned parallel to the demolding direction. This makes it possible to design an insertion area (16) of the shaft core (10) with a uniform outer cross-section (20) over its entire length. Furthermore, a wound shaft is described which has at least one hollow shaft and at least one shaft core inserted laterally therein, wherein at least one of the shaft cores (10) is designed in the manner described above.