Collet Chuck Segmentation for Concentricity and Rigidity
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Solution Overview
Problem
Conventional ER collet chucks are flexible and offer a wide clamping range, but this flexibility results in poor concentricity and rigidity due to radial support over a short axial region, leading to potential tool tilting and damage during clamping.
Innovation Solution
The design incorporates a cylindrical section that forms a fit with the base body, reducing tilting and increasing support, along with narrower slots and radial relief bores to enhance concentricity and torsional rigidity, while maintaining a smaller clamping nut distance to prevent over-insertion and damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the collet is made flexible with wide slots to increase clamping range, then the clamping range is improved, but the concentricity and rigidity deteriorate due to short axial support region
Solution Approach 1:
The collet is divided into functionally distinct sections: a flexible front section with slots for clamping range, and a rigid cylindrical rear section for precision support. This segmentation allows each zone to fulfill its specific function without compromising the other.
Solution Approach 2:
Different regions of the collet are given different mechanical properties - the front section has wide slots for flexibility and adaptability, while the rear cylindrical section has no slots or narrow slots for rigidity and precision, creating local quality variations that resolve the contradiction.
2Adaptability or versatility
If the collet is forced further into the receiving bore to increase clamping range, then the clamping range is improved, but the wall may bulge and the collet may tilt causing damage
Solution Approach 1:
The cylindrical section with transition fit is designed in advance to establish proper positioning and load distribution before the clamping action occurs, preventing bulging and tilting during operation.
Solution Approach 2:
The transition fit section acts as a cushioning zone that absorbs and distributes clamping forces before they reach the critical wall regions, preventing damage while allowing the collet to be forced further into the receiving bore.
3Manufacturing precision
If narrow slots are used to improve concentricity, then the concentricity is improved, but the clamping range is reduced
Solution Approach 1:
The slot configuration is segmented into different regions: wide slots in the front section for clamping range and no slots or narrow slots in the rear section for concentricity, allowing both requirements to be met simultaneously in different zones.
Solution Approach 2:
The slot width varies locally along the axial length of the collet - wide slots where clamping range is needed, and narrow or no slots where concentricity is critical, creating local quality differences that resolve the contradiction.
4Adaptability or versatility
If the clamping nut is positioned further from the front end to allow deeper collet insertion, then the clamping range is improved, but the risk of over-insertion and damage increases
Solution Approach 1:
The transition fit section is designed in advance to establish proper positioning limits, so the collet self-limits its insertion depth through the interference fit, preventing over-insertion damage while allowing sufficient clamping range.
Solution Approach 2:
The cylindrical section with transition fit acts as an intermediary element between the collet and the receiving bore, mediating the insertion process and providing a controlled interface that prevents harmful over-insertion while enabling adequate clamping range.
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
This design significantly improves concentricity and durability by ensuring the collet is centered and supported, reducing tilting errors and material fatigue, and preventing damage to the collet and base body, while maintaining precision and stiffness in tool clamping.
Implementation Method 1
The tool inserted into the collet with its cylindrical shaft is clamped radially when the clamping nut is tightened, which forces the collet into the receiving hole and thus reduces the inner diameter of the collet
Implementation Method 2
a clamping nut which forces the collet axially into the receiving hole relative to the receiving hole
Implementation Method 3
the collet points directly to, i.e. in relation to, the front end of the base body behind the conically tapering section has a cylindrical section which, together with a cylindrical section of the bore, forms a fit, in particular a transition fit
Data Source
AI summary
The invention relates to a high-precision clamping device (1a) for tools in machine tools of the conventional type and to a collet chuck (7a), a base (2a) and a tensioning nut (10a). The invention also relates to a chuck key for tightening the locknut (10a) without radial stress. The clamping device (1a) according to the invention is characterized by a substantially improved runout accuracy, torsional rigidity of the collet chuck (7a) and rigidity of the tool clamped therein.