Screw Element Blank Undercut Forming Without End-Face Deformation
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Solution Overview
Problem
Existing methods for producing screw elements and nuts with undercuts for improved imperviousness and adjustability face limitations, particularly in cold extrusion, where the formation of undercuts between the shaft and head is constrained, leading to material deformation issues and unsatisfactory friction coefficients.
Innovation Solution
A method involving the formation of a blind hole with multiple sections in the screw element blank, where material is displaced from the blind hole to create an undercut at the crossover between the shaft and head, allowing for cold extrusion without additional machining steps and enabling a flat end face or protrusion, and the use of a washer to secure the nut captively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If cold extrusion is used to produce screw element blanks with undercuts, then material usage is optimized and additional machining steps are eliminated, but the formation of undercuts is constrained and end-face deformation occurs
Solution Approach 1:
The invention applies preliminary action by forming the blind hole with varying cross-sectional areas before the final undercut formation. The blind hole is created with a first section having a larger cross-sectional area and a second section having a smaller cross-sectional area, which prepares the material structure for subsequent undercut formation without requiring additional machining steps. This preliminary structuring enables the cold extrusion process to achieve precise undercut geometry while avoiding end-face deformation.
2Reliability
If machining is used to produce the undercut in the blank, then the undercut can be produced safely and independently of the overall shape, but material loss occurs and additional clamping and turning steps are required
Solution Approach 1:
The invention merges the undercut formation process with the cold extrusion process itself. By designing the blank with a blind hole having varying cross-sectional areas during the cold extrusion step, the undercut is formed as an integral part of the extrusion process rather than as a separate machining operation. This merging eliminates the need for additional clamping, turning, and machining steps, thereby reducing process complexity while maintaining reliable undercut production.
3Manufacturing precision
If the shaft is widened by forming a deepening or blind hole on the end facing away from the head, then the undercut is formed, but the end face cannot remain flat or equipped with protrusions
Solution Approach 1:
The invention applies segmentation by dividing the blind hole into multiple sections with different cross-sectional areas. The first section has a larger cross-sectional area that extends toward the end face, while the second section has a smaller cross-sectional area that enables undercut formation. This segmentation allows the material displacement to be concentrated in specific zones, preserving the flatness or protrusion features on the end face while still achieving precise undercut geometry through the varying cross-section of the blind hole.
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 screw elements with improved imperviousness and adjustability, overcoming the limitations of traditional cold extrusion by enabling the formation of undercuts without end-face deformation and providing precise control over friction coefficients.
Implementation Method 1
the shaft being widened in sections, thus forming an undercut at the crossover between the shaft and the head, in particular by at least indirectly displacing material from at least the second section of the blind hole
Implementation Method 2
The advantage of these methods for producing gland blanks and glands using cold extrusion lies on the one hand in the optimized or free-of-loss material usage
Data Source
AI summary
The invention relates to a method for producing a gland or a gland blank (3), the method comprising a step of producing a blank (3) having a cylindrical shaft (5) formed on a screw head (4), and a blind hole (7) being formed in the blank (3) from an upper side (11) of the screw head (4) facing away from the shaft (5) in a, in particular further, method step, the blind hole (7) extending toward the shaft (5) and forming at least one first section (13), in particular having a polygonal cross section (Q1), preferably for receiving a screw tool. The blind hole (7) is deepened, thus forming at least one second section (14), which borders the first section (13), in a subsequent method step, the second section (14) forming a preferably at least partially continuous cross section (Q2) which is in particular smaller in size than the first cross section (Q1), the shaft (5) being widened in sections, thus forming an undercut (15) at the crossover between the shaft (5) and the screw head (4), in particular by at least indirectly displacing material from at least the second section (14) of the blind hole (7), in the subsequent method step.