| High-pressure monomer pump is key component of high power density XX engine fuel supply system,high monomer pump valve core is a solid of revolution by conical surface and cylinder,it need high surface quality,dimensional accuracy and shape accuracy requirement,it has been plagued our country domestic monomer pump oil pressure fluctuations,oil shortage,poor consistency of the important reasons.Due to the defense industry in China started late,in the aspect of equipment manufacturing and precision parts processing technology accumulation is less,monomer pump valve core precision machining equipment and processing technology enterprises dominated by a few developed countries.It is an urgent problem to improve the precision machining technology of high pressure monomer pump in our country.Based on the program(51318020206)"XX engine monomer pump precision machining technology",we make a deep theoretical and experimental research high voltage monomer pump valve core precision machining equipment and processing technology.The key components of the valve core precision grinding machine(body and guide rail)are studied with the design and machining.In addition,these methods are introduced into the structure design of the spindle precision grinding machine bed and guide rail,and the development of the valve core precision grinding machine is completed.Based on the self-developed valve core precision grinding machine,the precision machining technology of valve core is studied.High pressure oil supply system monomer pump valve core processing using precision grinding machine and technology,assemble valve core and other parts,the oil pump oil pressure experiment,the instantaneous oil pressure up to 1800 bar,close to international advanced level,the technical results have been applied in the northern institute of engine and broke the foreign technology monopoly.The main research contents and conclusions are as follows:1.Based on the shape structure and dimension precision of the valve core,the shape of the grinding wheel plug valve core was developed,and the grinding process of the entire outer surface through one clamp.Analyzes the power unit form and quantity of valve core grinding,the design of valve core grinding machine is done,present accuracy error distribution method.By adopting optimized linear guide way such as stroke,grinding wheel dressing,NC interpolation,without increasing accuracy of unit,the precision of the grinding machine increased by 49%,by lowering parallelism error between the center line of the workpiece axis and Z axis guide rail,the grinder movement unit met the requirement in the process of processing and debugging,effectively improve the whole machining precision of the grinding machine.2.Aiming at the problems of large size and multi-detail bed structure optimization data,difficulty of convergence and long calculation time,an innovative method of bed structure optimization based on unit method is proposed.In this paper,the structure of stud unit is put forward,and the structure deformation and frequency coupling optimization of stud unit is carried out.The weight of bed unit is reduced by 13.47 %,the deformation increases by 0.0003 mm and the frequency increases by 3.19%.At the same time,the flatness measuring method of the complex structure bed is put forward.By splitting the bed surface into overlapping rectangular detection units,and detecting the flatness of each square detection unit,the method of vibration combination is used to synthesize the plane error of each square detection unit to realize the flatness detection of the complex bed structure.3.Through analysis guide parts processing difficulty and guide assembly difficulty to guide rail structure,solves the hydrostatic guideway structure forms,hard to judge implementation difficulty.The method to choose the small parts processing difficulty,easy heat treatment,clamping location process easy,flexible gap adjusting static pressure guide rail structure,realizes the hydrostatic guideway design process optimization,complete the hydrostatic guideway structure design.4.Studies the guide rail rigidity influence of the guide gap.The experimental results show that with the increase of the guide rail gap,the stiffness correspondingly becomes smaller,and the deviation of the guide rail is easy to occur.With the decrease of the guide rail gap,the stiffness correspondingly becomes larger,so that the guide rail runs smoothly,and the relationship between the gap size and the rigidity of the guide rail becomes a parabola.Theoretical analysis shows that with the decrease of the guide rail gap,the stiffness correspondingly becomes larger,the relationship between the gap size and the rigidity of the guide rail is vary inversely.There is a slight difference with experimental result.Because of the error of guide rail.Flip measurement method,solve the guide rail line precision measuring error due to the ruler errors,the precision of the guide rail line error below 0.27 mm / 250 mm.5.An innovative grinding method is proposed to integrate grinding the cone surface and cylindrical surface.Adopted small arc narrow edge large diameter grinding wheel for grinding,through clamped on both ends of the valve core orientation,internal drive valve core rotary,using the grinding wheel side circular grinding valve core conical surface,at the same time,using the grinding wheel cylindrical grinding valve core cylinder surface.Using this grinding method,the grinding process of all valve core outer surface realized through a single clip,and the grinding machine has simple structure,high grinding precision and good consistency of grinding surface.6.Based on the grinding method of the valve core conical surface and cylindrical surface,the calculation model of the clamping force was established,and the influence of the clamping force on the valve core deformation was studied.The results show that in the valve core elastic deformation range,the valve deformation is larger with the clamping force increasing,the maximum deformation zone is the inner cone and the cylindrical ring groove area.At the same time,studied the method of circular grinding wheel grinding conical surface,establishing the mathematical model of point grinding giving mathematical model of circular isometric grinding valve core cone surface,identified the circular grinding segmentation criterion,according to the principle of arc grinding wheel grinding the valve core cone surface,presented based on the arc grinding contact arc length,non-deformation in grinding the approximate calculation method of critical grinding parameters such as cutting depth,and circular grinding on the surface of the cone valve core mechanics model is established.The technical measures to reduce the grinding force are explored,which lays a foundation for the selection of experimental parameters in the subsequent grinding process.7.Carried out the test of valve core grinding,and analyzed the influence of grinding parameters on the straightness and surface quality of the valve core.The results show that,with the increase of the grinding wheel speed,the linear degree of the valve is increased.With the increase of the axis speed of the workpiece,the straightness of the valve core decreases correspondingly.As the grinding depth decreases,the valve core straightness increases correspondingly.Under the condition of grinding depth,the surface quality of the valve cone surface increases with the increase of grinding wheel speed.With the decrease of axial feed,the surface quality of the cone surface increases accordingly.With the increase of the workpiece shaft speed,the surface roughness of the valve core becomes worse.The valve core grinding process was tested by the optimized grinding parameters of the valve core,and the straightness error of the valve core was lower than 0.75 mm /100 mm,and the surface roughness was less than 0.025 mm.8.The oil supply and pressure experiment were carried out for the same new single pump.It is found that,under the condition of the fixed oil supply pre angle and the continuous angle,with the increase of the camshaft speed,the quantity deviation of the oil supply decreases correspondingly and the oil supply pressure increases.When the camshaft speed was 1200r/min,the maximum instantaneous oil supply pressure reached 1811.34 bar.At the same time,the different monomer pump oil testing experiment,the test results show that with the improvement of the camshaft speed,oil supply difference decreases,and the camshaft speed at 1000 r/min,the consistency of oil supply is best.On this basis,the main factors affecting the consistency of oil supply are analyzed.Study found that the electronic control unit pump plunger,pump body,valve core processing precision,the electromagnetic coil impedance difference,the non-uniformity of engine speed will affect the oil supply consistency,oil supply difference is inevitable in the practical work,through improve the machining accuracy,improve the structure of fuel supply,optimizing control strategy to reduce oil supply.Through this project,giving the monomer pump valve core precision machining equipment production method and valve core processing method,this paper involves the design and the optimization method of the grinding machine key components are also applicable to other structural parts.The machining process of the valve core can be used for the processing of complex rotary body structure.The research can provide some theoretical guidance and reference for the development of complex structure rotary parts precision machining technology in China. |
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