RESTORATION AND HARDENING OF PLUNGER PAIRS OF HIGH-PRESSURE FUEL PUMPS

Abstract

The character and wear values of plunger pairs of high-pressure fuel pump is described. Plunger pairs of diesel fuel pumps work in conditions of high loadings and considerable wear. Plunger and sleeve precision surfaces are subjected to various types of wear, abrasive one being prevail. Geometrical parameters of the parts leading to the decrease in cyclic fuel supply, hydraulic density, change of the intake angle and others are varied. Methods of plunger pair restoration and hardening by means of high hardness coating on the precision surface are analyzed and compared. Technological process of carbide-chrome coating by virtue of diffusive chromium plating (vacuum and gas method) of a plunger and a sleeve made of steels ХВГand 25Х5М is described. Special features of plunger and sleeve machining are described. To increase capability and restoration of plunger pairs of high-pressure fuel pumps a method of diffusive chromium plating is proposed. The latter means that the parts are covered with a layer of hard coating. This results not only in hardening parts but also in compensating for their wear. Purpose – to determine methods of plunger pair restoration and hardening by virtue of high hardness coating on the precision surface. Method and techniques – technological process of carbide-chrome coating by virtue of diffusive chromium plating (vacuum and gas method) of a plunger and a sleeve made of steels ХВГand 25Х5М is given. Results: capability and restoration of high-pressure fuel pump plunger pairs are increased by using a method of diffusive chromium plating. Field of result application: it makes sense to use the results obtained to increase capability and restoration of high-pressure fuel pump plunger pairs.

Keywords

• плунжерная пара
• износ
• диффузионное хромирование