Ball Screw Nut Sleeve Case-Hardening With Weldable Flange
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for producing threaded nuts with ball threaded drives face challenges in achieving a simple and reliable connection to machine parts after hardening, particularly due to the high carbon content and martensitic structure of sheet steels.
Innovation Solution
A method involving the production of a sleeve from low-carbon steel sheet, which is case-hardened and provided with a diffusion-inhibiting layer on the welding surface to prevent carbon penetration, allowing for a straightforward welding connection to machine parts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If sheet steel with low carbon content is used for machining without cutting, then the ease of manufacture is improved, but the ability to be hardened through heat treatment deteriorates
Solution Approach 1:
The carbon content parameter of the steel sheet is changed from high to low to enable machining without cutting, while the hardening capability is restored through a different mechanism (case-hardening process) rather than the original heat treatment method
Solution Approach 2:
A diffusion-inhibiting layer is introduced as an intermediary element that prevents carbon penetration during case-hardening in specific regions, enabling selective hardening of the sleeve while keeping the welding section soft and weldable
2Strength
If sheet steel is carburized and case-hardened to achieve hardening, then the strength is improved, but the ability to be welded deteriorates due to high carbon content and martensitic structure
Solution Approach 1:
The sleeve is given different local qualities: the rolling contact areas are case-hardened to be hard and wear-resistant, while the welding section is protected by a diffusion-inhibiting layer to remain soft and weldable, creating spatially varying material properties
Solution Approach 2:
The diffusion-inhibiting layer acts as a mediator that selectively blocks carbon diffusion during case-hardening, protecting the welding section from becoming too hard and brittle, thus preserving weldability in that specific region
3Ease of manufacture
If a diffusion-inhibiting layer is applied to the welding surface to prevent carbon penetration, then the weldability is improved, but the device complexity increases due to additional processing steps
Solution Approach 1:
The diffusion-inhibiting layer is applied in advance to the welding section before the case-hardening process, so that when case-hardening occurs, the welding section is already protected and will not absorb excessive carbon, eliminating the need for post-processing to preserve weldability
Solution Approach 2:
The diffusion-inhibiting layer is temporarily applied during the case-hardening process and then removed after hardening is complete, serving its protective function only when needed and being discarded afterward to leave a clean welding surface
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 enables the production of threaded nuts that can be easily and reliably connected to machine parts, overcoming the limitations of high carbon content and martensitic structure, while maintaining a hardened rolling profile suitable for ball threaded drives.
Implementation Method 1
A welding surface of the welding section is provided with a diffusion-inhibiting layer which inhibits the penetration of carbon into the welding surface
Implementation Method 2
The sleeve is case-hardened, wherein under the carburization the carbon penetrates in particular into the areas that serve as raceways for the balls
Implementation Method 3
The diffusion-inhibiting layer can be formed by copper. This layer can be electroplated or plated on
Data Source
AI summary
The disclosure relates to a method for producing a threaded nut of a threaded drive. In a forming process, a sleeve is produced from a steel sheet which is suitable for case-hardening. A flange is integrally formed on the sleeve for welding to a machine part. A welding surface of the flange has a diffusion-inhibiting layer which inhibits the penetration of carbon into the welding surface. The sleeve is case-hardened, and the welding surface is then exposed by removing the diffusion-inhibiting layer. The sleeve can be bonded to a machine part on the exposed welding surface of the sleeve.