Centering Bolt With Local Recesses For Sheet Metal Riveting
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Solution Overview
Problem
Existing centering and fastening elements for sheet metal parts require high reshaping forces, especially with larger shaft diameters, leading to undesired deformations and difficulties in achieving secure attachment and centering, particularly with thicker metal sheets.
Innovation Solution
Incorporating local recesses in the conical wall and ring-like base surface of the ring recess provides security against rotation, allowing for reduced reshaping forces and preventing deformation, while ensuring adequate rotational security and proper rivet bead formation for secure attachment and centering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If noses providing security against rotation are added to the ring recess, then rotational security is improved, but the reshaping process becomes difficult and sheet metal deformation occurs
Solution Approach 1:
The local recesses are pre-formed in the conical wall of the ring recess before the riveting process. This preliminary preparation allows the sheet metal to be properly reshaped during riveting without being obstructed by rotation-preventing features, as the material can flow into the pre-existing recesses rather than having to deform around protruding noses.
Solution Approach 2:
Instead of adding protruding noses to prevent rotation (as in prior art), the invention inverts the approach by creating local recesses (depressions) in the conical wall. This inversion transforms the problem from one where protrusions obstruct material flow to one where recesses guide and accommodate material flow during reshaping, while still providing rotation prevention through the interlocking of sheet metal into these recesses.
2Measurement precision
If larger shaft diameters are used for centering elements, then centering accuracy is improved, but reshaping forces increase significantly
Solution Approach 1:
The conical wall of the ring recess is equipped with multiple local recesses distributed around its circumference. These localized features allow the sheet metal to be reshaped in a distributed manner rather than requiring uniform high forces across the entire contact area. Each local recess acts as a stress relief zone, enabling larger shaft diameters to be used for improved centering accuracy without proportionally increasing the required reshaping forces.
3Strength
If the rivet bead is formed with high forces, then attachment strength is improved, but sheet metal deformation and rivet section deformation occur
Solution Approach 1:
The local recesses in the conical wall act as pre-prepared cushion zones that absorb and distribute the forces generated during rivet bead formation. When the die button forms the rivet bead, the sheet metal can flow into these recesses, cushioning the impact and preventing concentrated forces that would cause deformation of the rivet section or unwanted deformation of the sheet metal, while still achieving sufficient attachment strength.
Data Source
AI summary
An element attachable to a sheet metal part by riveting, in particular an element in the form of a centering bolt, having a shaft part and a head part, wherein the head part has at its side confronting the sheet metal part an at least approximately ring-like ring recess which merges at the radially inner side into a cylinder section of the head part which in turn merges into the shaft part and into a tubular rivet section which surrounds the shaft part in the region of the head part, is disposed within a ring-like contact surface arranged radially outside of the ring recess and merges at the radially outer side via an at least approximately conical wall into the ring-like contact surface, is characterized in that at least one local recess and preferably a plurality of in particular uniformly distributed local recesses is or are provided in the conical wall of the ring recess and/or in an optionally present ring-like base surface of the ring recess. A component assembly comprising the element and a sheet metal part and also a method for the manufacture of such a component assembly are also described.