Self-Locking Collet Clamping for Hollow Shaft Reliability
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Solution Overview
Problem
Existing clamping mechanisms for hollow shafts are complex, prone to imbalance, and have high maintenance costs due to numerous components and sensitive manufacturing tolerances, leading to reliability issues and short lifespan.
Innovation Solution
A self-locking clamping device with a collet and operation stud featuring external tapered sections that securely clamp parts without pre-load units or locking units, utilizing friction and elastic deformation for self-locking, reducing the number of components and simplifying the design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing clamping mechanisms with pre-load units and locking units are used, then secure clamping force is achieved, but device complexity and number of components increase
Solution Approach 1:
The patent removes the pre-load unit and locking unit from the clamping mechanism, retaining only the essential collet and operation stud components. This extraction of non-essential elements reduces device complexity while maintaining the core clamping function through the tapered geometry of the remaining components.
Solution Approach 2:
The clamping mechanism achieves self-locking through the elastic deformation of the collet body and friction between the tapered surfaces of the operation stud and collet. The system serves itself by utilizing the inherent elastic properties and friction of its components to maintain clamping force without requiring separate pre-load or locking units.
2Manufacturing precision
If numerous components and sensitive manufacturing tolerances are used, then clamping precision is achieved, but maintenance costs and lifespan are negatively affected
Solution Approach 1:
By removing the pre-load unit and locking unit, the patent reduces the number of components that require manufacturing and maintenance. The simplified design with fewer sensitive parts lowers manufacturing complexity and reduces ongoing maintenance costs while extending the mechanism's operational lifespan.
Solution Approach 2:
The patent utilizes the elastic deformation characteristics of the collet body as a functional parameter, transforming a material property into a mechanism for achieving and maintaining clamping precision. This approach replaces complex mechanical assemblies with a simpler elastic deformation-based solution that is more durable and easier to manufacture.
3Reliability
If pre-load units and locking mechanisms are included, then clamping reliability is improved, but dynamic behavior and speed performance deteriorate
Solution Approach 1:
The removal of pre-load units and locking mechanisms eliminates additional moving parts and potential imbalance sources, allowing the clamping mechanism to perform reliably at high speeds without the dynamic penalties associated with complex mechanical assemblies.
Solution Approach 2:
The self-locking mechanism utilizing elastic deformation and friction provides reliable clamping without requiring additional active components that would compromise dynamic performance. The system maintains reliability through its passive elastic and friction-based locking action, which is inherently suitable for high-speed rotation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution provides reliable, accurate, and durable clamping with reduced maintenance needs, improved dynamic behavior, and extended lifespan by eliminating the need for pre-load units and locking mechanisms, while maintaining secure clamping even under high-speed rotation.
Implementation Method 1
The clamping device is self-lockable by reversibly fixing the external taper of the operation stud and the collet or a part between the collet and the operation stud to each other. Although forces that might try to release this connection can be effective in direction of a releasing relative movement of the collet and the operation stud, the friction forces of the self-locking are higher in this direction such that the connection is not released.
Implementation Method 2
A self-locking clamping device with a collet and operation stud featuring external tapered sections that securely clamp parts without pre-load units or locking units, utilizing friction and elastic deformation for self-locking
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
This invention concerns a clamping device (1) for firmly holding a part to be clamped (2) at a clamping recess (3) in which the clamping device (1) is arranged, the clamping device (1) comprising: - a collet (10) with a first external protrusion (103) for engagement with an internal recess (25) in an inner peripheral area of the part that is to be clamped (2) and with a second external protrusion (104) for engagement with an internal recess (36) in an inner peripheral area of the clamping recess (3), wherein at least one of the first external protrusion (103) and/or the second external protrusion (104) comprises a first external taper (1031) and/or a second external taper (1041), respectively, for pulling the part to be clamped (2) axially into the clamping recess (3) by a radial outward movement of the collet (10) or a section of the collet (10) and - an operation stud (13) including an external tapered section (131, 132) for effecting the radial outward movement of the collet (10), wherein the connection between the operation stud (13) and the collet (10) is self-locked and pre-loaded after a clamping movement of the operation stud (13) in axial direction that locks and pre-loads, - the external taper of the operation stud (13) and - the collet (10) or a part between the collet (10) and the operation stud (13) with each other. Further, the invention concerns a method for a part (2) to be clamped in a clamping recess (3).