Grinding machine for ultra-precision machining of needle valve body end face of high-pressure common rail injector

Abstract

An ultra-precision machining grinder for the needle valve body end face of a high-pressure common rail fuel injector, including a needle valve body precise positioning clamping device, a pneumatic pushing device, two frequency conversion electric spindles, the needle valve body precise positioning clamping device is fixed and installed on On the bed, the pneumatic pushing device and two frequency conversion electric spindles are fixedly installed on the sliding table, the sliding table can move horizontally and vertically, the two frequency conversion electric spindles are arranged on both sides of the pneumatic pushing device, and the pneumatic pushing device It can carry out automatic feeding. The precise positioning and clamping device of the needle valve body can precisely position and clamp the needle valve body and drive it to rotate at high speed. The two frequency conversion electric spindles can sequentially grind the butt end faces of the needle valve body. When the needle valve body is sent to the inner hole of the self-centering expansion sleeve, it can be accurately positioned in the axial and radial directions, and can accurately control the three axial dimension accuracy of the needle valve body. Using the precision grinding frequency electric spindle as the grinding head can ensure the plane quality of the end face to be processed and the perpendicularity relative to the reference A.

Description

Technical field: [0001] The invention relates to the processing equipment of the fuel injection nozzle assembly in the high-pressure common rail fuel injector of the diesel engine, in particular to the processing equipment of the needle valve body of the fuel injection nozzle assembly. Background technique: [0002] High-pressure common rail (Common Rail) EFI technology refers to the closed-loop system composed of high-pressure oil pump, common rail pipe, pressure sensor, electronic control unit (ECU) and common rail injector. The generation and injection processes are completely separate from each other. The high-pressure oil pump delivers high-pressure fuel to the public fuel supply pipe (Rail), and the electronic control unit (ECU) realizes precise control of the oil pressure in the public fuel supply pipe. The pressure of the high-pressure fuel pipe (Pressure) has nothing to do with the engine speed Timing, quantitative and precise fuel injection to the cylinder can gre...

AI Technical Summary

Problems solved by technology

[0005] It is understood that in foreign countries, the end face processing of the needle valve body of the high-pressure common rail injector is positioned on the outer circle of the needle valve body, and the three processes of rough grinding, fine grinding and super fine grinding are carried out step by step. The clamping of the body is the same as the processing method of domestic oil pump nozzle parts, both of which use image 3 The shown self-centering expansion sleeve is clamped. When the expansion sleeve is tightened, the workpiece will move with the expansion sleeve in the axial direction. The needle valve body has no stable positioning reference in the axial direction. The three axial dimensional accuracy of fuel injection quantity is 39.6 -0.08 、40.23 -0.01 and 42.1 +0.05 Difficult to meet design requirements, poor stability

At the same time, the needle valve body needs to be installed three times during the grinding process, and there are installation errors, which will easily lead to the out-of-tolerance of the verticality of the butt end face 53 relative to the reference A; the grinding of the butt end face 53 is completed by a common high-speed grinding head , the flatness, straightness and surface roughness of the butt end face 53 sometimes fail to meet the requirements; such processing technology and grinding processing equipment not only require more auxiliary time, but also have a low yield rate, which leads to the high pressure common rail injector One of the objective reasons for the high price of products is that the main quality defects in the processing process are manifested in the following aspects:

[0006] ① The flatness, straightness and surface roughness of the butt end face 53 cannot meet the requirements, and the stability is poor;

[0008] ③Three axial dimensions for controlling the fuel injection volume 39.6 -0.08 、40.23 -0.01 and 42.1 +0.05 The accuracy is too poor and the stability is not high

[0009] Through the above objective analysis, it can be seen that in the existing diesel engine high-pressure common rail injector, the design of the butt joint end surface grinding process of the needle valve body is unreasonable, and the processing quality is unstable with the existing cylindrical grinding machine, especially the needle valve body. The installation and positioning method is unreasonable, the clamping of parts does not have a unified positioning reference in the axial direction, and there are misalignment errors in multiple installation and clamping

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