Chuck Pressure Piece Torque Decoupling
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Solution Overview
Problem
Existing clamping devices face issues with reliable clamping and easy disassembly of tool shanks at high clamping forces due to increased friction and torque transmission, leading to potential collet collapse and excessive disassembly effort, as well as uneven force distribution caused by suboptimal longitudinal slot distribution.
Innovation Solution
The clamping device incorporates a pressure piece with non-rotating coupling elements to prevent torque transmission, a bayonet lock for secure angular connection, and optimized longitudinal slot designs for flexible force transmission, ensuring torsion-proof positioning and secure tool holding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the clamping nut is rotated to achieve high clamping forces, then the clamping force on the tool shank is improved, but torque transmission to the collet causes the collet to twist and unreliable clamping
Solution Approach 1:
A non-rotating pressure piece is introduced as an intermediary between the clamping nut and the collet. The pressure piece transfers the axial clamping force from the clamping nut to the collet without allowing torque transmission, as it is prevented from rotating by coupling elements engaged with the tool holder. This resolves the contradiction by decoupling the force transmission function from the rotation function.
2Ease of operation
If the collet is connected to the clamping nut using a snap-fit connection for easy removal, then the ease of operation is improved, but the snap connection is too weak to transmit the necessary tensile force at high clamping forces
Solution Approach 1:
The pressure piece serves as a mediator that bears the full clamping force from the clamping nut, allowing the snap-fit connection between the collet and clamping nut to be weakened for easier removal. Since the pressure piece transfers the load to the tool holder, the collet-clamping nut connection only needs to handle minor forces, resolving the contradiction between easy removal and sufficient strength.
3Ease of operation
If longitudinal slots are added to the collet to enable radial movement for clamping, then the ease of operation is improved, but suboptimal distribution leads to uneven distribution of clamping force
Solution Approach 1:
The longitudinal slots are strategically distributed around the collet circumference with optimized spacing and positioning. This non-uniform, locally optimized arrangement ensures that the slots are positioned to best accommodate the stress distribution and force transmission paths during clamping, achieving both radial movement capability and uniform clamping force distribution.
4Reliability
If coupling elements are added to prevent pressure piece rotation, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The coupling elements that prevent pressure piece rotation are integrated into the existing structural components of the clamping device. The coupling elements are formed as part of the pressure piece and tool holder geometry, merging the anti-rotation function with the existing clamping structure, thus improving reliability without significantly increasing device complexity.
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 solution enables secure clamping and easy release of tool shanks at high forces, preventing collet collapse and ensuring reliable, efficient operation with improved force distribution and reduced wear, while allowing for quick and accurate assembly.
Implementation Method 1
The radial force required to clamp the tool shank is achieved by connecting the clamping nut to the tool holder via a threaded connection. When the clamping nut is rotated relative to the tool holder, the collet's conical outer surface shifts against the conical inner surface of the tool holder.
Implementation Method 2
the collet has a cylindrical bore for receiving a tool shank and a conical outer surface for bearing against a corresponding conical inner surface of the tool holder. This compresses the collet radially, clamping the tool shank in the collet's cylindrical bore.
Implementation Method 3
the pressure piece is rotatably mounted relative to the clamping nut by means of at least one rolling bearing. This allows the pressure piece to be moved longitudinally relative to the clamping nut by the clamping nut, while significantly reducing friction between the clamping nut and the pressure piece.
Implementation Method 4
When the clamping nut is rotated relative to the tool holder, the collet's conical outer surface shifts against the conical inner surface of the tool holder. This compresses the collet radially, clamping the tool shank in the collet's cylindrical bore.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
Disclosed is a chucking device 1 for a tool, said device comprising a tool receiving element 2, a collet 5 for clamping the tool, said collet being inserted in an opening 9 in the tool receiving element 2, a clamping nut 3 for axially displacing the collet 5 in relation to the tool receiving element 2 and a pressure piece 4 which is arranged between the clamping nut 3 and the collet and is rotatably mounted in relation to the clamping nut 3, by means of which piece the collet 5 can be axially displaced in relation to the tool receiving element 2 by the clamping nut 3. To permit a tool shank to be securely clamped in and released from the collet 5, even under extremely high clamping forces, the pressure piece 4 has coupling elements 12 for a torsion-proof connection to corresponding mating elements 13 of the tool receiving element 2.