Collet Chuck Roller Clamping for High Tensile Force
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Solution Overview
Problem
Existing devices for clamping workpieces to collet chucks fail to withstand high tensile forces due to limited clamping forces and Hertzian stress limitations.
Innovation Solution
The device employs radially adjustable clamping elements in the form of rollers with tangentially aligned axes and a curved outer shape, allowing for line contact with the workpiece holder and clamping mandrel, thereby distributing clamping forces effectively and reducing surface pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If clamping balls are used to clamp the workpiece holder to the collet chuck, then the clamping device is simple in structure, but the clamping force is limited due to Hertzian stress
Solution Approach 1:
The patent applies curvature by designing the clamping elements as rollers with curved outer surfaces that match the radius of the workpiece holder circumferential surface. This curved geometry enables line contact instead of point contact, distributing the clamping force along the contact line and reducing Hertzian stress, thereby increasing the maximum clamping force the device can withstand
2Device complexity
If point contact clamping elements are used, then the device structure is simple, but the surface pressure is high and tensile force capacity is limited
Solution Approach 1:
The curved outer surface of the rollers is designed with a radius corresponding to the workpiece holder circumferential surface radius, creating line contact that distributes pressure over a larger area and reduces peak surface pressure
Solution Approach 2:
The patent transitions from point contact (zero-dimensional contact area) to line contact (one-dimensional contact area) by using rollers with curved surfaces. This dimensional change in the contact area significantly reduces the concentration of stress and pressure at the contact points
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 the device to securely clamp workpieces under greater tensile forces by optimizing the clamping force distribution, enhancing the device's ability to handle higher loads without failure.
Implementation Method 1
the radius of the curve corresponding to the radius of the workpiece holder circumferential surface such that in the clamping position the rollers are advantageously in line contact with the workpiece holder circumferential surface
Implementation Method 2
the surface pressure when the clamping forces securing the workpiece holder are generated can be considerably reduced
Data Source
AI summary
Device for clamping a workpiece holder on a collect chuck that can be fixed to a machine tool, having clamping elements distributed around the circumference of the collet chuck. The clamping elements can be adjusted radially to the axis of the collect chuck from a release to a clamping position and can be pressed against a circumferential surface of the workpiece holder positioned relative to the collet chuck in the clamping position. The clamping elements are designed as rollers having axes aligned nearly tangentially to the collet chuck circumference. A determinable surface pressure thus results in the clamping position as the rollers mutually contact the workpiece holder, a clamping mandrel of the collet chuck, and the collect chuck part. The surface pressure is thereby reduced and the collet chuck can also be used in the range of greater tensile forces.