Laser micro-modelling method for cam surface profile

Abstract

The invention relates to a laser composite processing technology for friction pair surfaces of cam rollers, in particular to a laser microscopic reshaping and modifying processing method carried out on cam surfaces of fuel injection pumps of engines. At first, the micro-geometrical morphology design scheme of the cam surface is determined; the laser micro-model processing of different morphology schemes are implemented by controlling laser processing technique parameters, namely the power density is 10<5> to 10<7>W / cm, the pulse width is 25ns to 200ns, the repetition frequency is 5KHz to 15 KHz, the scanning speed is 0r / min to 300r / min and the assistant gases of nitrogen or oxygen, and combining spatial tracks of work piece movements; and the micro-geometrical morphology with high hardness is formed by a micro-concave cavity and a micro-concave groove on the specific local working surface of the cam; the laser composite processing technology for the friction pair surfaces of the cam rollers not only can significantly improve the lubrication property of the cam surface, improve the wear resistance of the cams but also can prolong the service life of the cams and improve the whole property of the engines.

Description

technical field [0001] The invention relates to a surface micro-modeling technology, in particular to a laser micro-reshaping and modifying compound treatment technology on the surface of a cam of an engine fuel injection pump. Background technique [0002] The fuel injection pump cam is a major stressed component on a diesel / gasoline engine. When the engine is working, because the angle of the injection process is very small, the cam is loaded within a very narrow section of the wrap angle area, and it is always repeated in this range. Therefore, after a certain number of rolling cycles, this compressive stress will first cause pulling marks, pitting, peeling or excessive wear on the cam surface in the high load area of ​​the cam. Especially as the design of modern diesel / gasoline engines requires an increase in specific power and economy, the alternating load on the engine continues to increase, and the fuel system, as the heart of the engine, puts forward higher requirem...

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Problems solved by technology

Chinese patent 96109918.6 new method of intermediate frequency quenching of cams. This method uses the base circle preheating method to uniformly heat the working surface of the cam. Although it solves the quenching cracks caused by uneven heating temperature and inconsistent hardness in the existing cam strengthening treatment, Heat treatment defects such as overheating and soft spots, but there are defects such as surface residual stress and unsuitable control of heating temperature

But so far, due to the lack of basic theoretical research on laser micro-modeling and the fact that only a few countries have mastered laser micro-modeling technology, laser micro-modeling technology has not been applied to high-pair contact surfaces such as cam rollers.

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