Steep Thread Screw Drive Self-Lubricating Sintered Nut
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Solution Overview
Problem
Conventional screw drives face issues with lubricant decomposition at high speeds, leading to increased friction and wear, and require frequent maintenance, while also being complex and costly to produce.
Innovation Solution
A screw drive design featuring a spindle nut with an open-pored structure impregnated with a synthetic hydrocarbon oil or mesogenic liquid, combined with a high-helix thread and sintered metal or ceramic components, which reduces relative speeds and ensures continuous lubrication without additional lubricants, simplifying production and extending maintenance intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional lubricants are used in screw drives operating at high speeds, then the screw drive can function initially, but the lubricant decomposes due to coking, leading to increased friction and wear
Solution Approach 1:
The patent changes the chemical composition parameters of the lubricant by using synthetic hydrocarbon oils with specific molecular structures (cyclic alkanes, aromatic hydrocarbons) that have higher thermal stability and resistance to coking at high temperatures and speeds
Solution Approach 2:
The lubricant is formulated as a composite mixture containing multiple components including synthetic hydrocarbon oils, mesogenic liquids, and additives that work together to provide both high-speed lubrication and thermal stability
2Reliability
If the lubricant is replaced at regular intervals to prevent decomposition, then friction and wear are reduced, but maintenance effort and complexity increase
Solution Approach 1:
The screw drive system is designed to be self-sufficient by using a lubricant that automatically resists decomposition through its inherent chemical stability, eliminating the need for external maintenance interventions like regular lubricant replacement
3Ease of operation
If a minimal pitch angle is used to achieve low self-friction and direct motor drive, then the thread efficiency is improved, but the relative speed between spindle components increases, causing lubricant decomposition
Solution Approach 1:
The patent optimizes the pitch angle parameter to a specific range (3-10 degrees) that balances two competing requirements: maintaining low self-friction for direct motor drive capability while limiting the relative speed between thread surfaces to prevent lubricant decomposition
4Reliability
If a sliding coating or sintered material is used for the spindle nut to reduce friction, then the tribological properties are improved, but the production complexity and cost increase
Solution Approach 1:
The patent uses a homogeneous sintered bronze material for the spindle nut that inherently provides the required tribological properties through its uniform composition and structure, eliminating the need for additional sliding coatings or complex multi-layer constructions
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 design significantly reduces lubricant decomposition, increases service life, and simplifies production, resulting in a low-maintenance, high-load-capacity screw drive with reduced maintenance needs and longer operational life.
Implementation Method 1
The open-pored structure of the spindle nut material is able to absorb a sliding fluid used to lubricate the screw drive and continuously release it during operation
Implementation Method 2
Due to the high-helix thread, the relative speed between the threaded spindle and the spindle nut is relatively low, even at rapid advance speeds of the screw drive, so that there is less risk of the lubricant used decomposing or coking
Data Source
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AI summary
The present invention relates to a threaded drive (1) comprising a threaded spindle (2) and a spindle nut (3). The spindle nut (3) has at least one threaded portion (4) made of a sintered material with an internal thread (5). The internal thread (5) engages with an external thread (6) of the threaded spindle (2). According to the invention, the internal thread (5) and the external thread (6) are designed as steep threads.