Hollow Bolt Longitudinal Grooves Rolling Deformation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The manufacturing of hollow bolts with circumferential notches is challenging due to radial deformation caused by excessive pressure during the rolling process, as the material inside the longitudinal bore lacks sufficient strength to absorb these pressures, leading to increased production costs and the need for additional operations.
Innovation Solution
A hollow bolt blank with a longitudinal bore surrounded by annular walls with longitudinal grooves is used, allowing the material displaced during rolling to flow into these grooves, reducing pressure and preventing deformation, enabling the rolling of circumferential notches without deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If circumferential notches are rolled onto a hollow bolt with a longitudinal bore, then the production process is simplified, but the hollow bolt deforms radially due to excessive pressure
Solution Approach 1:
The annular wall of the hollow bolt is segmented by introducing longitudinal grooves that divide the continuous wall into sections. These grooves create discrete regions that can independently accommodate material displacement during rolling, preventing the buildup of excessive pressure that would cause radial deformation of the entire bolt structure.
Solution Approach 2:
The longitudinal grooves create local variations in the annular wall structure, providing specific zones (the grooves) with different mechanical properties compared to the elevations. The grooves act as local material reservoirs that can absorb compressive forces during rolling, while the elevations maintain the overall dimensional stability of the bolt.
2Adaptability or versatility
If a longitudinal bore is provided in the hollow bolt, then adjustment capability is enabled, but material strength to absorb rolling pressures is insufficient
Solution Approach 1:
The solution moves from considering only the radial dimension (where the longitudinal bore weakens the structure) to incorporating the longitudinal dimension by adding grooves along the length of the bolt. This dimensional addition creates a three-dimensional material distribution that strengthens the annular wall against radial pressures while preserving the central longitudinal bore for adjustment tools.
3Productivity
If material is displaced during rolling, then circumferential notches are formed, but interruptions occur in the thread production
Solution Approach 1:
The longitudinal grooves effectively extract or remove specific portions of the annular wall material in advance, creating predetermined voids or low-density zones. During rolling, displaced material naturally flows into these pre-created spaces rather than causing interruptions or defects in the thread formation process, ensuring continuous and uniform circumferential notches.
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 method allows for the production of hollow bolts with rolled threads or rings without deformation, reducing production costs and enhancing the self-tapping capability by minimizing interruptions in the thread, which increases the loosening torque of the screw.
Implementation Method 1
part of the material displaced when the indentations are rolled on flows into the longitudinal grooves without deformation of the annular wall
Implementation Method 2
pressure is exerted on the material of the hollow bolt that is deformed during rolling of the notches, which pressure can escape into free spaces formed by the longitudinal grooves
Data Source
Figure 1~4
AI summary
The invention relates to a method for producing hollow bolts (1) which comprise a longitudinal bore (6) and circumferential notches (11). The hollow bolts are provided with longitudinal grooves which extend between elevations that determine the bolt diameter while circumferential notches are rolled onto the hollow bolts encompassing the longitudinal grooves and the elevations. The cross section of the longitudinal grooves is selected such that some of the material that is displaced when the notches are rolled on flows into the longitudinal grooves.