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Needle valve and precise tiny electric spark processing method for conical surfaces of needle valve body

A precision machining and EDM technology, applied in the field of micro EDM precision machining, can solve the problems of reduced machining accuracy of the inner cone surface, shape error of the needle valve cone surface, and difficulty in machining, so as to achieve no mechanical cutting force and improve shape error , The effect of high processing flexibility

Inactive Publication Date: 2014-01-01
TSINGHUA UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the processing of the outer cone surface of the needle valve, since the length-to-diameter ratio of the needle valve is greater than 10, it is a slender shaft with low rigidity. When grinding with a grinding wheel, due to the existence of mechanical cutting force, the needle valve will produce a certain amount of bending deformation. , so that the shape error of the processed needle valve cone surface is not high, and the roundness is not high; while in the processing of the needle valve body cone surface, the rotation speed of the grinding wheel is 100000r / min, and at the same time, due to the small diameter of the needle valve body cavity, the processing method used The diameter of the grinding wheel is small, and the problem of grinding wheel wear is serious during processing, resulting in a reduction in the machining accuracy of the inner cone surface
The needle valve and the needle valve body also need to undergo heat treatment processes such as quenching and low temperature tempering. If the grinding process is placed before the heat treatment, the heat treatment will change the size of the parts. If the grinding process is placed after the heat treatment, the heat treatment will cause Significantly increase the hardness of parts, making machining more difficult and reducing machining accuracy

Method used

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  • Needle valve and precise tiny electric spark processing method for conical surfaces of needle valve body
  • Needle valve and precise tiny electric spark processing method for conical surfaces of needle valve body
  • Needle valve and precise tiny electric spark processing method for conical surfaces of needle valve body

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Experimental program
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Effect test

Embodiment 1

[0033] Such as figure 1 and image 3 As shown, the device of this embodiment includes a rotating spindle mechanism 1, a wire electrode wire mechanism, a pulse power supply 3, a numerical control system 4, a liquid tank 5, a needle valve 6, a needle valve body 7, a tool electrode 8 and a tooling 9; the rotating spindle mechanism 1. It can clamp the needle valve 6 or the tool electrode 8 to realize up-and-down movement and rotary movement. The whole movement process is controlled by the numerical control system 4; the wire-electrode wire-feeding mechanism includes a wire-feeding motor 21, a torque motor 22, an electrode wire 23, and a guide block 24 , guide wheel 25, wherein, wire-feeding motor 21 is active motor, drives electrode wire 23 to advance with lower speed (speed range: 0~25mm / min), and torque motor 22 outputs constant torque, keeps the tension force of electrode wire, The guide block 24 can control the cone angle of processing and transfer the electric energy of the ...

Embodiment 2

[0042] The processing device of this embodiment is different from Embodiment 1 in that: the shape, position and direction of the guide block 24 and the guide wheel 25, the electrode wire 23 is placed on the front end protruding part of the guide block 24 and vertically by the conversion of the guide wheel 25 on the axis of the needle valve.

[0043] Such as figure 2 As shown in b, the outer cone surface of the needle valve of the diesel engine fuel injector assembly in this embodiment includes the following steps:

[0044] (1) Roughly machine the outer cone surface at the top of the needle valve 6 in advance;

[0045] (2) Winding the electrode wire 23 on the EDM wire electrode wire running mechanism, connecting the pulse power supply 3 negative pole for EDM with the guide block 24;

[0046] (3) Install the needle valve 6 in the rotating spindle mechanism 1, and connect the positive pole of the pulse power supply 3 for EDM with the needle valve 6;

[0047] (4) Inject the wo...

Embodiment 3

[0051] The processing device of this embodiment differs from that of Embodiment 1 in that: the wire-feeding mechanism is removed, and the tooling 9 is changed to a tooling for fixing the needle valve body.

[0052] Such as image 3 As shown, the taper surface inside the needle valve body of the diesel engine fuel injector pair in this embodiment includes the following steps:

[0053] (1) Roughly machine the inner cone surface in the needle valve body 7 in advance;

[0054] (1) Fix the needle valve body 7 on a specific tooling 9, and connect the positive pole of the pulse power supply 3 for electric sparks to the needle valve body 7;

[0055] (2) Install the pre-processed tool electrode 8 that is consistent with the shape of the outer cone of the needle valve 6 on the rotating spindle 1, and connect the negative pole of the pulse power supply 3 for electric discharge machining to the electrode;

[0056] (3) Inject the working fluid into the liquid tank 5 to ensure that the ED...

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Abstract

The invention discloses a precise tiny electric spark processing method for an outer conical surface and an inner conical surface of a needle valve body of an oil nozzle coupling member of a diesel engine, belonging to the technical field of special processing. The precise processing method comprises the following steps of: processing the outer conical surface of the needle valve by adopting a wire electrode moving and processing method, wherein needle valves with different conical angles can be processed through adjusting the moving angle of the electrode or the moving speed of a rotating main shaft mechanism and a wire electrode moving mechanism; and using an another electrode to process the inner conical surface of the needle valve body by adopting the tiny electric spark processing method, wherein the shape of the another electrode is consistent with that of the outer conical surface of the needle valve. The precise tiny electric spark processing method disclosed by the invention has the characteristics of simple processing device, high processing accuracy and high sealing performance of a processed conical surface; and a better processing method is provided to process the needle valve of the oil nozzle coupling member and the conical surfaces of the needle valve body.

Description

technical field [0001] The invention belongs to the technical field of special processing, and mainly relates to a fine electric spark precision machining method for the outer conical surface of a needle valve and the inner conical surface of a needle valve of a fuel injection nozzle of a diesel engine. Background technique [0002] The fuel supply system of diesel engine is an important part of diesel engine. Its performance and technical status not only directly affect the power, economy and reliability of diesel engine, but also have an extremely important impact on environmental pollution. In the fuel supply system of a diesel engine, the three precision couplings, namely the plunger coupling, the fuel delivery valve coupling and the fuel injection nozzle coupling, are processed with extremely high precision, and the requirements for their sealing and wear resistance are very strict. Among them, the fuel injector assembly is a key component that affects the performance, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23H9/00B23H1/00B23H7/26
Inventor 李勇张龙李晓民佟浩
Owner TSINGHUA UNIV
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