Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M61/00—Fuel-injectors not provided for in groups F02M39/00 - F02M57/00 or F02M67/00
  • F02M61/16—Details not provided for in, or of interest apart from, the apparatus of groups F02M61/02 - F02M61/14
  • F02M61/168—Assembling; Disassembling; Manufacturing; Adjusting
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H3/00—Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte
  • B23H3/04—Electrodes specially adapted therefor or their manufacture
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
  • B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
  • B23H9/02—Trimming or deburring
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M55/00—Fuel-injection apparatus characterised by their fuel conduits or their venting means; Arrangements of conduits between fuel tank and pump F02M37/00
  • F02M55/02—Conduits between injection pumps and injectors, e.g. conduits between pump and common-rail or conduits between common-rail and injectors
  • F02M55/025—Common rails
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
  • F02M2200/00—Details of fuel-injection apparatus, not otherwise provided for
  • F02M2200/80—Fuel injection apparatus manufacture, repair or assembly
  • F02M2200/8069—Fuel injection apparatus manufacture, repair or assembly involving removal of material from the fuel apparatus, e.g. by punching, hydro-erosion or mechanical operation

Definitions

• the invention relates to the production of channels in a fuel injection device, and more particularly to the deburring of the mouth of a channel in a cavity.
• a fuel injection device As is known, the injection of fuel into an engine takes place under increasing pressure.
• pressures of the order of 1,500 bars are currently used, and pressures of up to 20,000 bars can be envisaged.
• Such pressures are in particular sought to improve engine performance, including from the point of view of environmental impact.
• there is a tendency to seek higher pressures for diesel engines the injection device is then commonly called “rail”, often made of steel or the like
• petrol engines the injection device is then commonly called “ramp", commonly made of aluminum or the like.
• An injection device is in practice a body comprising channels opening into a cavity, and the pressures used require that there is good deburring at the mouth of the channels in the cavity, to avoid any detachment of particles during service, such as machining chips.
• Various procedures have been set up for this purpose, including a so-called chemical deburring procedure, the principle of which is presented in FIG. 1.
• a body 1 comprising a channel 2 opening into a larger channel 3.
• the channel 2 is in practice made at by means of a drill, and a deburring is useful for rounding, or chamfering, the edge at the mouth of this channel 2 in the channel 3.
• an electrode 4 is engaged in the channel which has just been made until presenting its stripped end 4A at the mouth to be deburred.
• This electrode is brought to a negative potential while the body 1 is a positive potential while the channels 2 and 3 are filled with an electrolyte maintained in recirculation so as to ensure good evacuation of the chemical deburring debris.
• This solution gives very good results and is widely used with satisfaction.
• it has drawbacks and limits.
• the distance between the end of the negative electrode (cathode) and the edge to be deburred must be precisely controlled, it is necessary to have an electrode geometry for each diameter possible drilling. It must also be possible to precisely control the depth to which the end of this electrode is engaged.
• the invention proposes for this purpose a method of producing a channel in a fuel injection device according to which a channel is created in the body of this device opening out through a mouth into a cavity, an electrode is placed in the cavity, this electrode being provided with a stripped zone facing this mouth, and a difference of potential between this body and this electrode, in the presence of an electrolyte circulating in the cavity so as to deburr by electro-erosion the periphery of this mouth.
• the stripped portion of the electrode used has substantially the same dimensions as a stripped end according to conventional procedures, therefore with in particular a diameter substantially smaller than that of the canal whose mouth is to be deburred.
• the stripped portion of the negative electrode it is important that the stripped portion of the negative electrode either at similar distances from the internal surfaces of the small channel and the cavity connected by this edge.
• the stripped portion of the electrode has dimensions at least equal to those of the section of the channel which opens out.
• the same electrode is used to, simultaneously, deburr several mouths of channels in the same cavity, which leads to a significant reduction in cost.
• This single electrode can thus include a longitudinal row of bare areas. It can also include a ring of such stripped areas for deburring at once the mouths of an annular plurality of channels arranged around the longitudinal axis of the electrode.
• the single electrode can also have an annular rib, taking advantage of the fact that the geometry of the bare area can be defined fairly freely, independently of the precise geometry of the channels; thus there can be continuity between the bare areas intended to cooperate with each mouth.
• the cavity can be a channel of constant section, and open at its ends. It can also be a dead end pocket, the access to which may have a smaller section than that of the pocket at the location of the mouths to be deburred. It is then possible to use a laterally extendable electrode capable of bringing the stripped areas of the mouths to be deburred transversely to the axis.
• this bare area has dimensions smaller than those of the mouth, - this bare area has dimensions at least equal to those of the mouth, electro-erosion of the periphery of this mouth leading to the appearance of counterbore on at least part of this periphery, - the dimensions of this bare area are generally between once and twice that of the mouth deburring, - EDM is conducted to a maximum depth of counterbore which can reach several millimeters, for example of the order of a tenth of a millimeter, - the depth of the counterbore is equal to or greater than of hundredth of a millimeter, - the electrode is provided with several stripped zones and the electro-chemical deburring of several mouths of channels opening into the cavity is carried out simultaneously - deburring of several mouths offset longitudinally in the cavity, - Simultaneously deburring several mouths offset radially around a longitudinal axis of the cavity, - To simultaneously deburr several mouths
• the invention further provides, for implementing the method, an electrode comprising at least one bare area projecting transversely.
• this electrode possibly combined: - it comprises a plurality of stripped projections offset longitudinally along the axis of this electrode, - it comprises a plurality of stripped projections angularly offset around the longitudinal axis of this electrode , - the plurality of projections forms a continuous annular rib, - the angularly offset projections are radially movable.
• the invention further provides an injection device, the body of which comprises a cavity into which opens at least one channel, characterized in that the mouth of this channel in the cavity is surrounded, on at least part of its periphery, by a counterbore bordered by rounded areas of connection to the surrounding surfaces.
• - in this cavity open several longitudinally offset channels whose mouth is surrounded by a counterbore
• - in this cavity open several angularly offset channels whose mouth is surrounded by a counterbore
• - l the mouth has, with the counterbore, dimensions between once and three times the dimensions of the channel
• - the counterbore has a depth of at most a few millimeters, for example of the order of a tenth of a millimeter
• - the counterbore has a depth equal to or greater than about a hundredth of a millimeter
• - the cavity is a channel of constant section
• - the cavity is a dead end pocket.
• FIG. 1 is a schematic representation of a conventional deburring process chemical
• Figure 2 is a schematic representation of a chemical deburring process according to the invention
• Figure 3 is a schematic representation of another chemical deburring process according to the invention
• Figure 4 is a view enlarged view of the mouth of a canal in a cavity, deburred according to the method of FIG. 3
• FIG. 5 is a schematic representation of another method according to the invention for the simultaneous deburring of several mouths
• FIG. 6 is a variant
• Figure 7 is another variant.
• FIG. 2 represents an embodiment of the method of the invention, according to which, in a body 10 in which a cavity 13 and a channel 12 have been previously produced, a negative electrode 14 is placed, no longer in this channel 12, but in the cavity 13, in principle of larger size than the channel.
• This electrode has a bare area 14A, preferably made up of a projection.
• This projection is a lower height than the stripped end 4A of Figure 1, but a barely larger width. Indeed, this projection has dimensions smaller than those of the mouth to be deburred.
• This electrode and the body are put at appropriate potentials for an appropriate time, while a given electrolyte circulates under appropriate conditions (all these operating conditions are within the reach of the skilled person, in the light of his know-how developed with the classic procedure).
• FIG. 1 represents a variant of the method described with reference to FIG.
• channel 22 includes a large diameter section 22A and a smaller diameter section 22B, typically having the same diameter as the channel 12.
• the diameter of the section 22A is 4 mm, while that of the section is 1 mm.
• a rounded 26A in principle similar to that to that of FIG. 2 (here it has a radius of curvature of 0.2 mm).
• This rounding is connected to a flat or to any rounded shape, designated by the term counterbore, 26B which surrounds the mouth bordered by the round 26A.
• This counterbore is connected to the internal surface of the cavity 23 by a second rounded 26C, for example of curvature substantially equal to that of the rounded 26A.
• This counterbore can have a depth ranging from about a hundredth of a millimeter to a few millimeters.
• FIGS. 1 to 3 correspond to case where the cavity is a channel of constant section, in which the channels are offset longitudinally. It is easy to understand that, unlike the case of FIG. 1, the configurations of FIGS.
• the cavity 33 being of short length, the various channels are arranged radially with respect to the longitudinal axis of this cavity (vertical in this figure 5); one thus distinguishes, in this figure, two channels arranged diametrically opposite, respectively designated by 32 and 32 '.
• the production of such an injection device body, with a dead end cavity and radially arranged channels is known per se from document WO-99/60263 or its equivalent US-6196192 and will not be detailed here.
• an electrode 34 is engaged in the cavity, provided with bare areas 34A and 34A ', until these bare areas are positioned, here constituted by projections, as precisely as possible opposite the mouths of the channels (it can therefore there are some in front and behind the plane of the figure).
• a negative potential is applied to the electrode 34 while the body
• FIG. 30 is set to a positive potential while circulating in the cavity, all around the electrode 34, a suitable known electrolyte: simultaneously deburring of all the mouths of the channels opposite which have projections 34A or 34A '...
• Figure 6 shows an alternative embodiment of the electrode all the other elements of the body being identical.
• This electrode, denoted 44 comprises, opposite the mouths of the channels, no longer an annular plurality of individual stripped projections, but a continuous stripped rib 44A. In this way, it is no longer necessary to seek to position this electrode with great angular precision. However, it appeared that the deburring phenomenon obtained is quite similar to that obtained with the electrode 34 of FIG. 5.
• FIG. 7 represents an alternative embodiment of the electrode, all the other elements of the body being identical .
• This electrode 54 is transversely deformable, in the sense that the projections 54A and 54A 'are radially movable, here against a spring of reminder 55. More precisely, each projection is disposed at the end of a link and, by action on the end 56 common to these links, for example by means of a slide movable along the body 57 of this electrode, we can force the projection of the projections.
• An electrode thus makes it possible to arrange the projections at any suitable distance from the mouths to be deburred, independently of the passage section of the access opening to the cavity. As before, the simultaneous deburring of the mouths of the various channels is carried out, by adopting the appropriate operating conditions.
• the dimensions of the stripped projections are preferably between once and twice (advantageously between once and one and a half times) that of the mouthpieces to be deburred, and that the mouthpiece, after deburring, has a dimension worth, with the counterbore, between one and a half and three times the dimension before deburring (in FIG. 4, the ratio is barely greater than 2).

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Combustion & Propulsion (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Thermal Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Fuel-Injection Apparatus (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Cites Families (3)

• 2004
  • 2004-01-09 FR FR0400193A patent/FR2864916A1/fr active Pending
• 2005
  • 2005-01-06 WO PCT/FR2005/000021 patent/WO2005072899A2/fr not_active Ceased
  • 2005-01-06 EP EP05717369A patent/EP1701814A2/de not_active Withdrawn

Non-Patent Citations (1)

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