Study On Wear Resistance And Wear Mechanism Of Resin-based Carbon Brush Materials Doped With Functional Additives

The carbon brush is used as a rotating electrical contact loss component in the power tool,and a special pair of friction pairs is formed with the commutator to conduct a current during the operation of the motor.Existing carbon brushes generally have problems of material mismatch and non-wear resistance due to poor mechanical strength or friction reducing lubrication performance,and the selection of functional additives is particularly critical for the improvement of anti-wear performance of carbon brushes.Most of the existing researches focus on the composite effect of additives,and improve the anti-wear performance of carbon brushes by means of various additives to improve the mechanism.The resulting mechanism of the additives in the carbon brush materials is also the interaction of various additives.There is little systematic study of the specific mode of action of a single additive to improve the anti-wear properties of carbon brushes.In this paper,the epoxy resin-based carbon brush material is difficult to improve due to poor mechanical strength or weak friction and lubrication performance.The resin-based carbon brush material for small and medium-sized electric drill motors is selected as the research object.“Structural control-mechanical properties-current-carrying wear properties-microstructural characterization-wear mechanism analysis”research ideas,using a variety of functional additives?fourteen kinds?doped resin-based carbon brush composites,and aggregates Together with the matrix binder,it is constructed as a"functionalized enhancement"structure.The effects of the introduction of graphene-like functional additives and disulfide self-lubricating additives on the anti-wear properties of epoxy-based carbon brush materials were systematically investigated.By comparing the mechanical strength and antifriction properties of the carbon brush materials before and after the introduction of different additives and different content additives,the mechanical strength improvement mechanism of the graphene-based additives in the epoxy resin-based carbon brush materials and the influence of disulfide additives were expounded.Friction reduction mechanism of dynamic friction film between friction pairs.The main findings are as:?1?In the system using epoxy resin as binder and natural flake graphite powder as conductive filler,graphene-like functional additives?sulfonated carbon nanopowder,FNG-A102,FNG-A151,FNG-B100,FNG-B111?were introduced.and disulfide self-lubricating additives?N-MoS₂,A-MoS₂,F-WS₂,P-WS₂,M-WS₂,C-WS₂,SC-WS₂,F-RXI-A,C-RXI-A?The main physical properties of the carbon brush material modified by the additive and the microscopic area were characterized.The results show that the size and quantity of the pores and microcracks of the modified carbon brush material have been improved to different extents.The carbon brush material to which no additive was introduced had a flexural strength of 19.97 MPa,a compressive strength of 20.33 MPa,and a Shore hardness of 12 HSD.Compared with the unmodified carbon brush material,the FNG-A151 additive increases the flexural strength of the carbon brush by 60.5%,and the sulfonated carbon nanopowder increases the compressive strength of the carbon brush by 18.5%,shore hardness increased by 51.7%;among the disulfide self-lubricating additives,the P-WS₂additive increased the flexural strength of the carbon brush by 51.6%,and the N-MoS₂additive increased the compressive strength of the carbon brush by 27%,C-RXI-A modified tungsten disulfide additive increases the shore hardness of carbon brushes by 59.2%.?2?The carrier wear properties of epoxy resin-based carbon brush materials before and after additive modification were studied,and the micro-wear regions were analyzed and characterized.The study found that the wear rate with the unmodified carbon brush sample were 7.75 mg/h and level 2 commutation spark grade,carbon brush wear rate modified by sulfonated carbon nanopowder reduced to 2.5mg/h and commutation spark grade controlled at level 1;modified tungsten disulfide by C-RXI-A the additive-modified carbon brush wear rate was reduced to 1.75 mg/h,and the commutation spark grade was also controlled at level 1.And through the micro-morphology analysis of the wear surface,the carbon brush wear surface modified by the sulfonated carbon nano-powder and C-RXI-A modified tungsten disulfide additive is smooth and flat,showing a“wave”layer progressive structure.By comparing and analyzing the effect of additives on the anti-wear performance of carbon brush materials,the sulfonated carbon nanopowder and C-RXI-A modified tungsten disulfide additive were selected for further study.?3?The comprehensive properties of sulfonated carbon nanopowders and C-RXI-A modified epoxy resin based carbon brush materials with different contents were studied in depth.The experimental results show that the mechanical properties of the carbon brush are improved to the greatest extent when both additives are added at 1 wt%,and the current-carrying wear rate and the commutation spark reach the lowest value.Appropriate amount of sulfonated carbon nano-powder helps to bond the interface between the flake graphite powder and the epoxy resin binder,and improves the anti-wear performance by improving the overall mechanical strength of the epoxy-based carbon brush material.The C-RXI-A modified tungsten disulfide additive helps to form a suitable thickness of the friction film between the friction pairs during the current-carrying wear process,which avoids the local accumulation of the wear debris and improves the interface adhesion.Occurs,thereby improving the wear resistance of the carbon brush material by improving the friction reducing performance.?4?Starting from the self-structure of sulfonated carbon nanopowders,the tensile mode at the interface was analyzed in depth,and the"multi-contact functional enhancement"structure of the sulfonated carbon nanopowder between the aggregate and the resin matrix interface was obtained.The wear resistance of the carbon brush material is improved by improving the mechanical strength of the carbon brush material.Through the in-depth analysis of the wear debris of the wear surface,the action model of the dynamic friction film affected by different sizes of tungsten disulfide is obtained,and the reduction of the carbon brush material is improved.Friction performance to improve its anti-wear performance.Provides a database of single-class additives for the study of current-carrying tribology,providing a reference for the accurate selection of additives in resin-based composites.