PVDF Sliding Bearing Composite Reducing Static Friction
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Solution Overview
Problem
Existing plain bearing composite materials with PTFE-based sliding layer materials face challenges in reducing static friction while maintaining adequate wear resistance, as adding friction-reducing fillers does not effectively lower the coefficient of friction, and PTFE has limitations in strength, thermal conductivity, and adhesion to metallic carriers.
Innovation Solution
A plain bearing composite material with a PVDF-based sliding layer material incorporating a filler in compounded form, where PVDF forms the matrix and the filler comprises thermoplastics like PEEK, carbon fibers, graphite, and titanium dioxide, which are finely distributed to reduce static friction without compromising wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If PTFE is used as the polymeric plastic base of the sliding layer material, then the coefficient of friction is reduced, but the wear resistance deteriorates and the strength is insufficient
Solution Approach 1:
The patent uses a composite material system where PTFE is combined with PVDF and fillers (graphite, PEEK, carbon fibers) to create a sliding layer material that achieves both low friction and high wear resistance. The PTFE content is optimized at 5-30 vol.% rather than using pure PTFE, balancing friction reduction with structural integrity and wear resistance.
Solution Approach 2:
The patent optimizes the PTFE content parameter within a specific range (5-30 vol.%) rather than using maximum PTFE content. This parameter optimization allows the material to achieve low coefficient of friction while maintaining adequate wear resistance and strength through the synergistic effect with PVDF and fillers.
2Object-affected harmful factors
If fillers are added to reduce friction, then the coefficient of friction decreases, but the wear resistance is compromised
Solution Approach 1:
The patent employs a multi-component composite system where fillers (graphite, PEEK, carbon fibers) are integrated with PVDF and PTFE matrix. This composite structure allows the fillers to contribute to friction reduction while the PVDF-PTFE matrix provides the structural framework that maintains wear resistance.
Solution Approach 2:
The patent creates different functional zones within the sliding layer material: the PTFE and graphite components provide low-friction surfaces, while the PVDF matrix and PEEK-filled regions provide structural support and wear resistance. Each component performs its specialized function in a localized manner within the composite structure.
3Object-affected harmful factors
If PTFE content is increased to reduce static friction, then the coefficient of friction decreases, but the thermal conductivity and adhesion to metallic carrier deteriorate
Solution Approach 1:
The patent optimizes PTFE content to 5-30 vol.% rather than using high PTFE content, balancing static friction reduction with thermal conductivity. The PVDF matrix, which has better thermal conductivity than PTFE, forms the primary structure, while the optimized PTFE content provides sufficient friction reduction without excessively compromising thermal performance.
Solution Approach 2:
The patent uses a PVDF-PTFE composite matrix where PVDF provides the structural framework with adequate thermal conductivity and adhesion to metallic carriers, while PTFE (at optimized content) provides friction reduction. This composite matrix structure allows simultaneous achievement of low static friction and acceptable thermal conductivity.
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 achieves a significant reduction in static friction while maintaining wear resistance, making the material suitable for applications like vehicle seat back adjustment devices and hydraulic radial piston motors, where low static friction and high wear resistance are crucial.
Implementation Method 1
PVDF forms the matrix and the filler comprises thermoplastics like PEEK, carbon fibers, graphite, and titanium dioxide, which are finely distributed
Implementation Method 2
the filler in compounded form is present in particle form and is incorporated in the matrix-forming polymeric plastic base... to reduce static friction without compromising wear resistance
Data Source
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AI summary
The invention relates to a sliding bearing composite material (2) with a metallic support layer (4), optionally with a porous carrier layer (6) applied thereto, and with a sliding layer material (8) based on polymeric plastics and containing fillers that improve the tribological properties, which is introduced into the pores of the carrier layer (6) or applied to the metallic support layer (4), and which is characterized in that the sliding layer material (8) comprises 65-90 vol.% PVDF as a polymeric plastic base and further 5-30 vol.% PTFE and 5-25 vol.-% of a filler (12) in compounded form, wherein the polymeric plastic base (8) is matrix-forming, and that the filler (12) in compounded form is in particulate form and is incorporated in the matrix-forming polymeric plastic base, and that the filler (12) in compounded form comprises a thermoplastic and other tribologically active substances, wherein the proportion of the thermoplastic in the compounded form is 40-95 vol% and the proportion of the other tribologically active substances in the compounded form is 60-5 vol%.