Concentric Shaft Fastening with Intermediary Bushing
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Solution Overview
Problem
Conventional fastening devices for shafts and rotary encoder shafts often result in offset due to uneven pressure forces, leading to instability and potential detachment issues, particularly with clamping rings that twist relative to the shafts.
Innovation Solution
A fastening device featuring a shaft bushing that compensates for diameter differences between shafts, combined with a clamping unit having axially directed alignment means and radially directed fixing means, ensuring concentric alignment and secure fixation of the shafts without special adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a clamping ring with radially inwardly directed pins and a secant-directed screw is used to fasten shafts, then the shafts can be fixed together, but the clamping ring can twist relative to the shafts and may come off due to tilting
Solution Approach 1:
A shaft bushing is introduced as an intermediary component between the shaft and the encoder shaft. The bushing has a bore that receives the shaft and an outer diameter that fits within the encoder shaft, providing a stable mounting surface for the clamping ring and preventing twisting or tilting movements that would compromise fastening reliability
Solution Approach 2:
The fastening system is divided into separate functional components: the shaft bushing for positioning and support, the clamping ring for securing, and the alignment/fixing screws for precise positioning and fixation. This segmentation allows each component to perform its specific function optimally without interfering with others
2Strength
If conventional fastening devices are used to fasten shafts and encoder shafts, then the shafts can be connected, but offset occurs due to uneven pressure forces leading to instability
Solution Approach 1:
The shaft bushing acts as a precision intermediary that establishes accurate concentric alignment between the shaft and encoder shaft. Its precisely manufactured bore and outer diameter ensure uniform pressure distribution when clamped, preventing offset and maintaining concentricity stability throughout operation
Solution Approach 2:
The shaft bushing is pre-positioned and aligned using the axially directed alignment screw before final tightening. This preliminary alignment action ensures that when the radially directed fixing screw is tightened, the shafts are already in correct concentric position, preventing instability caused by uneven pressure forces
3Strength
If a clamping ring is screwed tight using a screw pointing in the direction of a secant, then the three pins fasten the two shafts, but the clamping ring can twist relative to the shafts when the screw is actuated
Solution Approach 1:
Instead of using a secant-directed screw that acts on the clamping ring from the outside, the invention uses axially directed alignment screws that act through the shaft bushing from the inside. This inverted approach provides more stable alignment and prevents twisting during the fastening operation while maintaining assembly simplicity
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
To enable a concentric and mutually aligned fastening of a shaft (1) to a rotary encoder shaft (4), a fastening device (BV) for concentric fastening of the shaft to the rotary encoder shaft is provided according to the invention, comprising a shaft bushing (3) which is arranged between the shaft and the rotary encoder shaft and compensates for a diameter difference between the shafts; and a clamping unit (2) which aligns the shaft bushing to the rotary encoder shaft and fixes the shaft bushing and the rotary encoder shaft to the shaft, wherein the clamping unit has an axially directed alignment means for aligning the clamping unit and the shaft bushing to the rotary encoder shaft and a radially directed fixing means for fixing the shaft bushing, the rotary encoder shaft and the shaft.