Precision electric grinding process for fuel injector tiny ball seat surface of high-pressure common-rail diesel engine

Abstract

The invention relates to a precision electric grinding process for a fuel injector tiny ball seat surface of a high-pressure common-rail diesel engine and belongs to the technical field of micro non-traditional machining. The precision electric grinding process comprises steps of according to the size of the ball seat surface, designing and manufacturing a wire electrode guide plate with guide end semi-circular or arc; installing and positioning a ball seat surface workpiece and the wire electrode guide plate, and ensuring coaxial precision of symmetric axis of the guide plate and rotary symmetric axis of the ball seat surface workpiece; grinding a micro electric discharging wire to the set machining depth; grinding a micro electrolytic line to remove working allowance and polish the surface to reach machining technical requirements of the ball seat surface. According to the process, the same tool line electrode is utilized to perform online integration of micro electric discharging grinding and micro electrolytic grinding, the final shape and surface precision of the ball seat surface are achieved, and machining technical requirements of the tiny ball seat surface are achieved. The precision electric grinding process is suitable for machining the ball seat surface on a fuel injector control valve in a high-pressure common-rail diesel engine system and further suitable for machining high-precision axisymmetric concave surfaces on other conductive materials.

Description

technical field [0001] The invention belongs to the technical field of micro-special processing, and in particular relates to a precision electric grinding process for a micro-ball seat surface of a high-pressure common rail diesel engine injector, which is oriented to the precision machining of a concave micro-sphere crown surface applied to conductive materials such as metal alloys. Background technique [0002] The high-pressure common rail diesel engine system can realize high injection pressure (120MPa~200MPa), accurate and high-speed control of fuel injection timing and fuel injection volume, making it a powerful, economical and environmentally friendly high-performance internal combustion engine system. It is a complex integrated electromechanical hydraulic control system, representing today's comprehensive cutting-edge technology. High-precision parts also reflect the highest processing level in the current machinery manufacturing industry. [0003] The electronical...

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Problems solved by technology

However, due to the serious electrode loss problem in the EDM process, the existing micro-EDM process cannot meet the shape and dimension accuracy requirements of the micro-ball seat surface; and because of the micro-pit and heat-affected layer produced by EDM, It is also unable to meet the surface processing accuracy requirements of the tiny ball seat surface

[0007] The anode workpiece material of micro-electrolytic machining is removed in the form of ions, which has the potential to realize nano-mirror processing without heat-affected layer and no residual stress; but if it is affected by stray electric field (the electric field in the electrolyte reaches the anode workpiece, the material will be etched away ), it will not be possible to form a three-dimensional micro-cavity with high dimensional accuracy; the localized control method of low-concentration electrolyte, low processing voltage, and ultra-short pulse can effectively reduce or avoid the influence of stray electric fields, but it will cause three-dimensional cavity The efficiency of micro-electrochemical machining is extremely low, making it intolerable or even impossible to complete the machining process

This makes it difficult for the existing micro electrolytic machining process to meet the processing technical requirements of the micro ball seat surface

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