Rolled Thread Screw End Geometry for Burr-Free Thread Rolling
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Solution Overview
Problem
Rolled thread screws manufactured using in-feed thread rolling often produce burrs and sharp edges that require additional processing to remove, which affects production efficiency and yield.
Innovation Solution
The rolled thread screw design incorporates salient excess-thickness portions such as columnar and truncated cone parts, with concave surfaces and salient parts to prevent burrs, and a manufacturing method that plastically deforms the blank to form thread grooves and flat axial end surfaces, reducing the need for deburring and increasing production yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If in-feed thread rolling is used to manufacture rolled thread screws, then the manufacturing process is simpler and more direct, but burrs and sharp edges are generated on the screw surface
Solution Approach 1:
The patent applies preliminary action by forming specific geometric features (concave surfaces and salient parts) on the blank before thread rolling. The blank is pre-shaped with a first concave surface, second concave surface, and salient part that will prevent burr formation during the subsequent thread rolling process. This preliminary preparation eliminates the need for post-processing deburring operations.
Solution Approach 2:
The patent applies local quality by creating specific geometric features at particular locations on the blank. The first concave surface, second concave surface, and salient part are positioned at the end surface of the blank to locally modify the material flow during thread rolling. This localized geometric modification prevents burr formation only at critical areas without affecting the overall thread structure.
2Productivity
If post-process cutting is performed after through-feed thread rolling, then continuous long blank can be processed efficiently, but burrs and sharp edges are produced on the rolled thread screws
Solution Approach 1:
The patent applies preliminary action by pre-forming the blank with specific geometric features (concave surfaces and salient parts) before thread rolling. This preparation ensures that when cutting is performed after through-feed thread rolling, the pre-formed features prevent burr and sharp edge formation on the cut screw surfaces, eliminating the need for additional deburring operations.
3Manufacturing precision
If burrs are removed through post-processing, then surface quality is improved, but production time and cost increase
Solution Approach 1:
The patent converts the potentially harmful effect of material excess during thread rolling into a beneficial feature. By designing the blank with specific geometric features (concave surfaces and salient parts), the material that would normally form burrs is instead shaped into features that prevent burr formation. This converts what would be a harmful byproduct into a functional feature that eliminates the need for deburring operations.
Solution Approach 2:
The patent applies preliminary action by pre-forming the blank with specific geometric features (concave surfaces and salient parts) before thread rolling. This preparation ensures that when cutting is performed after through-feed thread rolling, the pre-formed features prevent burr and sharp edge formation on the cut screw surfaces, eliminating the need for additional deburring operations.
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
The solution effectively reduces burrs and sharp edges, enhances production efficiency, and improves the quality of the rolled thread screws by ensuring flat axial end surfaces, thereby increasing the effective length of the screw part and reducing post-processing work.
Implementation Method 1
a processing step of plastically deforming the blank into a rolled thread screw
Data Source
AI summary
A rolled thread screw includes: a screw part having, on an outer circumferential part of the screw part, thread crests and thread grooves disposed alternately along an axial direction of the rolled thread screw; and a columnar part adjoining at least one of both sides of the screw part in the axial direction. An axial end surface of the columnar part is provided with: a first concave surface concave in the axial direction; a second concave surface positioned to an outer circumference of the first concave surface and being concave in the axial direction; and a salient part positioned on a boundary between the first concave surface and the second concave surface and projecting further than a bottom of the first concave surface and a bottom of the second concave surface, the salient part extending in an arc-like shape along a circumferential direction of the columnar part as viewed in the axial direction.