Rolling Screw Actuator Spindle Material for Wear Resistance
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Solution Overview
Problem
Existing electromechanical actuators face challenges in managing wear, particularly in screw drives, due to the lack of effective materials and manufacturing processes that enhance the mechanical strength and wear resistance of components like threaded spindles and planets.
Innovation Solution
The use of a manganese steel composition with controlled carbon content (0.4 to 1.5% by weight) and deformation-induced martensite precipitation and work hardening, combined with heat treatment, to produce threaded spindles and planets with high surface hardness and core strength, ensuring enhanced mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional materials and manufacturing processes are used for threaded spindles and planets, then production cost and manufacturing simplicity are maintained, but wear resistance and mechanical strength are insufficient
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition parameters of the steel (carbon: 0.25-0.50%, silicon: 1.50-3.00%, manganese: 10.00-15.00%, chromium: 1.00-2.00%, molybdenum: 0.10-0.50%) and applying specific heat treatment parameters (austenitizing temperature, quenching temperature, tempering temperature) to achieve the desired mechanical properties and surface hardness
Solution Approach 2:
The patent creates a composite microstructure within the steel material itself, combining a martensitic core structure with a work-hardened surface layer containing deformation-induced martensite. This composite structure at the micro level provides both core strength and surface wear resistance
2Object-affected harmful factors
If material composition and heat treatment are optimized for high surface hardness, then wear resistance improves, but manufacturing precision and process control difficulty increase
Solution Approach 1:
The patent defines precise parameter ranges for material composition (carbon: 0.25-0.50%, silicon: 1.50-3.00%, manganese: 10.00-15.00%, chromium: 1.00-2.00%, molybdenum: 0.10-0.50%) and heat treatment processes to achieve the desired balance between surface hardness and core strength while maintaining manufacturability
Solution Approach 2:
The patent applies preliminary action through the material composition design and pre-heating treatment before thread rolling. The specific chemical composition and initial austenitizing treatment prepare the material in advance to enable successful work hardening during the forming process, ensuring the surface will develop the required hardness after deformation
3Object-affected harmful factors
If deformation-induced martensite formation is enhanced through material composition, then surface hardness increases, but impact toughness may decrease
Solution Approach 1:
The patent applies local quality by creating different microstructures in different regions of the material: a martensitic core structure for overall strength and toughness, and a work-hardened surface layer with deformation-induced martensite for wear resistance. The controlled material composition enables this spatial differentiation of properties
Solution Approach 2:
The patent creates a composite microstructure combining a martensitic core with a work-hardened surface layer containing deformation-induced martensite. This composite structure at the micro level provides both core strength and surface wear resistance
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 results in threaded spindles and planets with surface hardness up to 650 HV and core strength of 800 MPa to 1080 MPa, effectively resisting axial forces and impact loads, suitable for applications in motor vehicle steering actuators and industrial actuating mechanisms.
Implementation Method 1
deformation-induced martensite precipitation and work hardening
Implementation Method 2
deformation-induced martensite precipitation and work hardening
Implementation Method 3
combined with heat treatment, to produce threaded spindles and planets with high surface hardness and core strength
Data Source
AI summary
An electromechanical actuator includes a planetary rolling screw drive having a plurality of planets, a driven cage guiding the plurality of planets, and a threaded spindle. The threaded spindle has a formed thread with a finish produced by martensite precipitation and strain hardening. The threaded spindle is formed from a steel including 0.4 to 1.5% by weight of Carbon, 12.0 to 22.0% by weight of Manganese, up to 4.0% by weight of Chromium, up to 0.5% by weight of Nickel, up to 0.3% by weight of Copper, up to 0.3% by weight of Vanadium, up to 0.3% by weight of Sulfur, up to 0.1% by weight of Phosphorus, up to 4.0% by weight of Silicon, up to 0.05% by weight of Aluminum, and a remainder of iron and smelting-induced impurities.