CA1198951A - Method for producing a composite center electrode - Google Patents
Method for producing a composite center electrodeInfo
- Publication number
- CA1198951A CA1198951A CA000378603A CA378603A CA1198951A CA 1198951 A CA1198951 A CA 1198951A CA 000378603 A CA000378603 A CA 000378603A CA 378603 A CA378603 A CA 378603A CA 1198951 A CA1198951 A CA 1198951A
- Authority
- CA
- Canada
- Prior art keywords
- cup
- billet
- core
- metal
- composite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000004519 manufacturing process Methods 0.000 title abstract description 4
- 239000002131 composite material Substances 0.000 claims abstract description 38
- 238000001125 extrusion Methods 0.000 claims abstract description 33
- 239000002184 metal Substances 0.000 claims abstract description 32
- 229910052751 metal Inorganic materials 0.000 claims abstract description 32
- 238000000034 method Methods 0.000 claims abstract description 18
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 8
- 229910052802 copper Inorganic materials 0.000 claims description 5
- 239000010949 copper Substances 0.000 claims description 5
- 238000007493 shaping process Methods 0.000 claims description 4
- 238000005260 corrosion Methods 0.000 abstract description 5
- 230000007797 corrosion Effects 0.000 abstract description 5
- 238000010008 shearing Methods 0.000 description 11
- 238000005482 strain hardening Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 101150042035 Bpifa1 gene Proteins 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T21/00—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs
- H01T21/02—Apparatus or processes specially adapted for the manufacture or maintenance of spark gaps or sparking plugs of sparking plugs
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01T—SPARK GAPS; OVERVOLTAGE ARRESTERS USING SPARK GAPS; SPARKING PLUGS; CORONA DEVICES; GENERATING IONS TO BE INTRODUCED INTO NON-ENCLOSED GASES
- H01T13/00—Sparking plugs
- H01T13/20—Sparking plugs characterised by features of the electrodes or insulation
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Spark Plugs (AREA)
- Extrusion Of Metal (AREA)
- Forging (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improved method for producing a composite center electrode for a spark plug is disclosed. The method comprises the steps of forming from a corrosion-resistant metal a cup having a closed end, walls extending upwardly from the closed end to an open end and a cavity extending concentrically therein, and then forming a composite billet having closed and filled ends by inserting into the open end of the cup a billet of a metal having a high thermal conductivity and fitting tightly within the cup walls. The method also includes extruding the composite billet into an electrode blank having an upper headed portion and a lower portion of reduced diameter extending longitudinally therefrom. The improvement comprises the steps wherein the positions and the relative sizes of the billet and of the cup are controlled so that the former fits tightly within the cup walls adjacent the closed cup end, but terminating short of the open cup end so that the cup walls extend thereabove at the open cup end, and the cup walls adjacent the open cup end are rolled radially inwardly to form the composite billet. The method includes the additional improvement wherein the closed end of the composite billet is first inserted into a die having a stepped bore including an extrusion orifice of reduced diameter equal to that of a desired electrode head, and is then forced through the extrusion orifice to form an elongated composite billet. The elongated billet is inserted into a second die having a stepped bore including an extrusion orifice of reduced diameter, wherein all except an upper headed portion is forced through the extrusion orifice to form the composite center electrode.
An improved method for producing a composite center electrode for a spark plug is disclosed. The method comprises the steps of forming from a corrosion-resistant metal a cup having a closed end, walls extending upwardly from the closed end to an open end and a cavity extending concentrically therein, and then forming a composite billet having closed and filled ends by inserting into the open end of the cup a billet of a metal having a high thermal conductivity and fitting tightly within the cup walls. The method also includes extruding the composite billet into an electrode blank having an upper headed portion and a lower portion of reduced diameter extending longitudinally therefrom. The improvement comprises the steps wherein the positions and the relative sizes of the billet and of the cup are controlled so that the former fits tightly within the cup walls adjacent the closed cup end, but terminating short of the open cup end so that the cup walls extend thereabove at the open cup end, and the cup walls adjacent the open cup end are rolled radially inwardly to form the composite billet. The method includes the additional improvement wherein the closed end of the composite billet is first inserted into a die having a stepped bore including an extrusion orifice of reduced diameter equal to that of a desired electrode head, and is then forced through the extrusion orifice to form an elongated composite billet. The elongated billet is inserted into a second die having a stepped bore including an extrusion orifice of reduced diameter, wherein all except an upper headed portion is forced through the extrusion orifice to form the composite center electrode.
Description
~9~
The instant invention is based on the discovery of an improved method for producing a composi-te center electrode for a spark plug.
According to ~he invention the.re is provided a method of forming bi.metal electrodes, for spark plugs or the like, comE)risincJ
Eorming a first metal into a cup having an open end, a closed end, a cylindrlcal wall and a eentral opening which extends a distance from the elosed end to the open end, forming a right eireular cylindrieal eore from a seeond and different metal, said eore being sized to be reeeived in the eentral opening in elose fitting relationship with the wall therearound, and to extend from the elosed end toward the open end a distance less than Z, positioning said core in said central opening thereby orming a composite billet having first and seeond ends corresponding, respeetively, with the open and elosed ends of the cup, extruding at least a portion of the eomposite billet, seeond encl first, through an extrusion orifice of a die with a foree applied to the first end of the eomposite billet by an end of a tool, said foree beins applied so as to maintain substantial contact between said core and said elosed end of the cup while said extrusion is oeeurring.
From another aspeet, the invention provides an eleetrode for spark plugs or the like, eomprising a eore formed of one metal, sueh as eopper or the like, and an outer surface of a second metal at least partially eneapsulating said eore, said eleetrode being formed by partially extruding a eomposite produced by seating the eore metal within a eup shaped body of said second metal having open and elosed ends, said composite being partially extruded, elosed eup end first, through an extrusion die while simultaneously ~G
3i5 ~ ~
q3 maintaining substan-tially complete contact between said closed cup end and the core metal and shaping the unextruded open end of the cup to encapsulate the core at least partially.
Preferably, the open cup end, wlth tile right circular cylinc1rical billet positioned in the cavity thereof, is first inserted into a die havillg a cavity extendinc3 lon(31tudinally there-in to a lower concave surface and into which the cup fits tightly, and then forced against the concave surEaee to roll the cup walls adjacent the open cup end radially inwardly to form the eomposite billet.
Preferably also, the elosed end of the composite billet is first inserted into a die having a stepped bore including an upper bore in whieh the billet fits elosely and an extrusion orifiee of redueed diameter equal to that of a desired electrode head, and is -then forced through the extrusion orifice -to
The instant invention is based on the discovery of an improved method for producing a composi-te center electrode for a spark plug.
According to ~he invention the.re is provided a method of forming bi.metal electrodes, for spark plugs or the like, comE)risincJ
Eorming a first metal into a cup having an open end, a closed end, a cylindrlcal wall and a eentral opening which extends a distance from the elosed end to the open end, forming a right eireular cylindrieal eore from a seeond and different metal, said eore being sized to be reeeived in the eentral opening in elose fitting relationship with the wall therearound, and to extend from the elosed end toward the open end a distance less than Z, positioning said core in said central opening thereby orming a composite billet having first and seeond ends corresponding, respeetively, with the open and elosed ends of the cup, extruding at least a portion of the eomposite billet, seeond encl first, through an extrusion orifice of a die with a foree applied to the first end of the eomposite billet by an end of a tool, said foree beins applied so as to maintain substantial contact between said core and said elosed end of the cup while said extrusion is oeeurring.
From another aspeet, the invention provides an eleetrode for spark plugs or the like, eomprising a eore formed of one metal, sueh as eopper or the like, and an outer surface of a second metal at least partially eneapsulating said eore, said eleetrode being formed by partially extruding a eomposite produced by seating the eore metal within a eup shaped body of said second metal having open and elosed ends, said composite being partially extruded, elosed eup end first, through an extrusion die while simultaneously ~G
3i5 ~ ~
q3 maintaining substan-tially complete contact between said closed cup end and the core metal and shaping the unextruded open end of the cup to encapsulate the core at least partially.
Preferably, the open cup end, wlth tile right circular cylinc1rical billet positioned in the cavity thereof, is first inserted into a die havillg a cavity extendinc3 lon(31tudinally there-in to a lower concave surface and into which the cup fits tightly, and then forced against the concave surEaee to roll the cup walls adjacent the open cup end radially inwardly to form the eomposite billet.
Preferably also, the elosed end of the composite billet is first inserted into a die having a stepped bore including an upper bore in whieh the billet fits elosely and an extrusion orifiee of redueed diameter equal to that of a desired electrode head, and is -then forced through the extrusion orifice -to
-2 -"~^~
form an elongated composite billet having closed and filled ends, whereupon the closed end of the elongated composite billet is inserted into a second die having a stepped bore including an upper bore in tYhiCIl the billet fits closely and an e~trusion orifice of red~lced diameter, and all except ~n upper hcaded portion adjacent to the filled end of the elongatecl billet is forced through the extrusion orifice to form the composite center elec~rode. Therefore, the upper headed portion of the composite center electrode does not need shaping because the composite billet was first extruded to the desired diameter.
In the accompanying drawings:
Figure 1 is a partially schematic, vertical sectional view showing a corrosion-resistant metal cup and a right circular cylindrical billet of metal of high thermal conductivity prior to being inserted into the cup in accordance with a previously knowlllnetllod.
Figure 2 is a sectional view showing a composite billet ormed from the cup and billet of Figure 1.
Figure 3 is a partially schematic, vertical sectional view showing the composite billet of Figure 2 inserted into a bore of a die having within the bore an extrusion orifice.
Figure 4 is a sectional view showing an electrode blank formed from the cornposite billet of Figure 3 after all except a terminal portion thereof is forced through the extrusion orifice.
Figure 5 is a partially schematic, vertical sectional view showing a right circular cylindrical billet of corrosion-resistant metal inserted in~o a cavity of a die in accordance with the present invention.
Figure 6 is a sectional view showing a cup ormed by back~extruding the billet of Figure 5.
Figure 7 is a partially schematic, vertical sectional view showing a 5~
right circular cylindrical billet of metal of high thermal conductivity prior to being inserted into ~he cup of Figure 6.
Figure 8 is a sectional view showing the billet of Figure 7 inserted into the cup in Figure 7.
Figure 9 is a partially schematic, vertical sectional view shol~ing the billet and the cup of Figure 8 inserted into a cavity of a die.
Figure 10 is a partially schematic, vertical sectional view showing a composite billet formed from the cup and the billet within the cavity of the die of Figure 9, and inserted into a bore of a die having within the bore an extrusion orifice.
Figure 11 is a sectional view showing an electrode blank formed from the composite billet of Figure 10 after all except an upper headed portion there-of is forced through the extrusion orifice.
Figure 12 is a partially schemat.ic, vertical sectional view showing the electrode blank of Figure 11 positioned in a die having a stepped bore including an upper bore> a shearin~ shoulder, a second shoulder and a lower bore.
Figure 13 is a partially schematic, vertical sectional view showing a composite center electrode formed by shearing the upper headed portion of the electrode blank of Figure 12.
Figure 14 is a partially schematic, vertical sectional view showing a composite billet formed from the cup and the billet within the cavity of the die of Figure 9, and inserted into a bore o a die having within the bore an extru-sion orifice equal in diameter to that of a desired elec~rode head.
Figure 15 is a sectional view showing an elongated composite billet ~ormed by forcing the composite billet of Figure 14 through the extrusion orifice and> thereabove, a second composite billet in a par~ially deformed condition.
--4~
Figure 16 is a partially schematic, vertical sec-tional view showing the elongatec. composite bi]let of Figure 15 inserted into a bore of a d.ie having withill the bore an ex-trusioll ori.Eice.
Fiyure 17 is a sectiollal view showillg a compos.ite cetlte:r electrode :Eol-med ~rom the elongatecl billet o.t l?igu:re 1~ after all except an upper heclded por-tion thereof is forced thro-lgh the extrusion orifice.
Referrring -to E`igure 1, one method for producing composite center electrodes involves first forming a cup 10 from a corrosion-resistant metal, such as nickel. The cup 10 has a closed end 11, walls 12 extending upwardly from the closed end 11 to an open end 13 and a cavity 14 extendi.ng concentrically therein to a lower surface 15. A composite billet is then Eormed by posi-tioning interiorly of the eup 10 a close-Eitting right eireular eylindrical billet 1~, of a metal having a hicJh thermal conductivity, sueh as eopper. The billet 16 fits tightly within the cup walls 12 to form a eomposite billet indicated generally at 17 in Figure 2, having elosed and filled ends 18 and 19. The method fur-ther involves inserting the closed end 18 of the composite billet 17 into a die indicated at 20 in Figure 3, having a stepped bore 21 including an upper bore 22 in whieh the billet 17 fits closely and an extrusion orifice 23 of reduced diameter relative to the upper bore 22. Pressure is then applied to a plunger 24 to force a].l except a terminal portion 25 (Figure 4) of the billet 17 through the extrusion orifiee 23. ~n electrode blank 26 -thus formed has the unextruded terminal portion 25 as an upper headed portion, a lower portion 27 of reduced diameter extending longitudinally therefrom, and a copper core 28 extending therein. After the ~ 5 _ J
~ `~
electrode blank 26 is removed from the die 20, it is suitable for use as a composite center electrode for a spark plug. If desired, howevel-, the upper headed portion 25 can be shaped by cold-workinc3 or furt}ler extrusion into a more desirable e~ectrode~ he~ad con-L`i~uratio~ \n electrc~de assemhly is formed by weldillg a metal rod (not illustrated) to the upper heacled portion 25 of the electrode blank 26. The primary disadvantage of the method just described is the difficulty involved in welding the metal rod to the head 25 because the amount of niclcel remaining after the copper core 28 has been extruded therein is insufficient.
The present invention relates to an improved method Eor producing a composite center eleetrode for a spark plug as described in detail hereinafter.
Referrinc3 to Figure 5, a back-extruder indicated genercllly at 29 comprises a die 30 positioned on a platen 31 and having a right circular bore 32 extending therethrough. The back-extruder 29 also comprises a piston 33 extending through the pla-ten 31 in structural relationship with a floating ejector 34 which closes a lower opening oE the bore 32, and a plunger 35 having a diameter less than that of the bore 32 and insertable therein, and having a lower surface 36. A cavity indicated generally at 37 is Eormed by walls of the bore 32 and an upper surface 38 of the rloating ejector 34.
The first step of the method involves forming a cup from a right eircular cylindrical billet of a corrosion-resistant metal, sueh s niekel or niekel alloy. The eup can be formed by drilling or baek-extrusion, .he latter of which is preferred and comprises the following sub-steps. A right circular cylindrical billet 39 ~- 5a -of nickel alloy having an upper end 40 is sized to fit tightly against the walls o.E -the bore 32 when inserted therein. ~fter the billet 39 is in~serted into the cavity 37 of the bore 32 and super-posed on -tlle upper sur:Eace 38 oE the floatinq e,ec-tor 34, the plunc]er 35 is inserted therein agai.nst the upper end 40 of the billet 39. Pressure is then applied to the pl.unger 35 which pierces the billet 39 and causes back-extrusion there of to form a cup 41 as illustrated in Figure 6. The cup 41 has a closed end 42, walls 43 extending upwardly from the closed end 42 to an open end 44 and a cavity indicated generally at 45 extend~
~ 5b -5~
ing concentrically therein to a lower surface 46 which corresponds to the shape of the lower surace 36 of the plunger 35. After the plunger 35 is extracted from the cavity 45 of the cup 41, pressure is applied to the piston 33 W]liCh causes the floating ejector 34 to force the cup 41 out of the cavity 37 of the die 30.
Ti-e next step of the method involves forming a composite billet.
Referring to Pigure 7, a close-~itting right circular cylindrical billet 47 of a metal having a high thermal conductivity, e. g., copper, is inserted, as indi-cated by an arro~Y, into the open end 44 of the cup 41 and fits closely within the cup walls ~3. The copper billet 47 is compressed within the cavity 45 of the cup 41 into close-fitting relationship with the lower surface 46 thereof, as shown in Figure 8. The copper billet 47 fits tightly within the cup walls 43 adjacent the closed end 42, but terminates short of the open cup end 44 so that the cup walls 43 extend thereabove at the open end 44. Referring to Figure 9, a die indicated at 48 has a cavity 4~ extending longitudinally therein to a lower con-cave surface 50. After the open cup end 44 is inserted into the cavity 49 of the die 48, a plunger 51 is inserted therein against the closed end 42. Force is then applied to the plunger 51 to roll the cup walls 43 adjacent the open cup end 44 radially inwardly to substantially en~lose the billet 47 and to form a composite billet 52 having closed and inwardly turned ends 53 and 54 as illus-trated in Figure 10.
The next step of the method involves forming an elec~rode blank from the composite billet 52. Referring to Figure 10, a forward extruder indicated generally at 55 comprises a die 56 having a stepped bore 57 including an upper bore 58 in which the billet 52 fits closely and an extrusion orifice 59 of re-duced diameter relative to the upper bore 58. The forward-extruder 55 also com-prises a plunger 60 having a diameter equal to that of the upper bore 58 and ~85~5~
insertable therein, and a lower surface 61. After the closed end 53 of the bil-let 52 is inserted into the upper bore 58 of the die 56, the plunger 60 is in-serted therein against the inwardly turned end 54 of the billet 52. Ref~rring to ~igure 11, pressure is then applied to the plunger 60 which forces all ex-cept a terminal portion of the billet 52 thro-lgll the extrusio~ orifice 59 of the die 56 to form an electrode blank indicated generally at 62. The electrode blank 62 has the unextruded terminal portion of the billet 52 as an upper headed portion 63 and a lower portion 6~ o reduced diameter extending longitudinally therefrom, and a copper core 65 extending therein. After the electrode blank 62 is removed from the die 56, it is suitable for use as a composite center electrode for a spark plug. If desired, however, the upper headed portion 63 can be shaped by cold-working) further extruding, or shearing into a more de-sirable electrode head configuration. The latter of these is preferred.
The final step of the method involves shearing and shaping the upper headed portion 63 of the electrode blank 62. Referring to Rigure 12, a shearing and orming apparatus indicated generally at 66 comprises a die 67 having a stepped bore 68 including a right circular upper bore 69 extending to a shearing shoulder 70 of reduced diameter, a central bore below the shearing shoulder 70 and extending to a second shoulder 71, and a lower bore 72 extending rom the second shoulder 71 through the die 67. The first step of the improved method in-volves inserting the electrode blank 62 within the stepped bore 68. When the electrode blank 62 is so inserted, the upper headed portion 63 seats on the shear-ing shoulder 70 and fits closely within the upper bore 69, while the lower por-tion 64 fits closely within the lower bore 72. The shearing and forming appar-atus 66 also comprises a plunger 73 having a diameter subs~antially equal to that of the shearing shoulder 70 and inser~able therethrough9 and a lower sur-face 74.
~L9~
The plunger 73 is inserted concentrically within the upper bore 69 against the upper headed portion 63 of the electrode blank 62. Pressure is ~hen applied to the plunger 73 to force the upper headed portion 63 of the electrode blank 62 past the shearing sho-llder 70, leaving a ring 75 (Figure 13) of excess Inaterial, and against the second shoulder 71 (Figure 12) to form a desired com-posite center electrode indicated generally at 76 (Figure 13). The composite electrode 76 includes a head 77 and the rod 64 of the electrode blank 62 (Figures 11 and 12). The electrode head 77 (Figure 13) has an upper and under surface 78 and 79 conforming to the shape of the lower surface 74 (Figure 12) of the plunger 73 and the second shoulder 71 of the die 67 respectively. Although the lower surface 74 of the plunger 73 is illustrated as being concave, it can be of any shape necessary to form the upper surface 78 (Figure 13) desired for the electrode head 77. The electrode head 77 also has a cylindrical side 80 having a diameter equal to that of the shearing shoulder 70 (Figure 12) of the die 67. The com-posite center electrode 76 (Figure 13) is then removed from the die (Figure 12) through the upper bore 69 and is suitable for the desireduse without further cold-working or extruding steps.
The method includes the additional improvement wherein the composite billet 52 (Figure 10) formed by the cup 41 and the billet 47 within the cavity 49 of the die 48 of Figure 9 is first extruded to ~he desired electrode head dia-meter. The first step of the method involves forming an elongated composite bil-let from the billet 52. Referring to Figure 14, a forward-extruder indicated generally at 81 comprises a die 82 having a stepped bor~ 83 including an upper bore 84 in which the billet 52 fits closely and an extrusion orifice 85 ~f re-duced diameter relative to the upper bore 84andequal to that of the desired el trode head. The forward-extruder 81 also comprises a plunger 86 having a dia-meter equal to that of the upper bore 84 and insertable therein, and a lower surface 87.
After the closed end 53 of the billet 52 is inserted into the upper bore 84 of the die 8~ the plunger 86 is inserted therein against the in~ardly turned end 54 of the billet 52. Pressure is theTI applied to the plunger 86 whic}l forces all except a terminal portion of the billet 52 throug}l the extrusion orifice 85 of the die 82. The plunger 86 is withclrawll from the die 82 and a seconcl billet (not shown) similar to the first billet 52 is inserted therein and supelposed on the inwardly turned encl 54 of the first billet 52. The plunger 86 is then re-inserted into the upper bore 84 of the die 82 against the second billet. Refer-ring to Figure lS pressure is applied to the plunger 86 which compresses the second billet ~o an intermedia~e shape 88 and forces the rer~;n;ng terminal portion of the first billet 52 through the e~trusion orifice to form an elongated composite bille~ indicated generally at 89 and }laving closed and filled ends 90 and 91.
The final step of the laethod involves forming a composite center electrode from the elongated billet 89. Referring to Figure 16 a sec~nd forward-extruder indicated generally at 92 comprises a die 93 having a stepped bore 94 including an upper bore 95 extending to a shoulder 96 and an extrusion oriice 97 of reduced diameter adjacent and below the shoulder 96. The forward-extruder 92 also comprises a plunger 98 having a diameter equal to that of the upper bore 95 and insertable therein and a lower surface 99. After the closed end 90 of the elongated billet 89 is inserted into the upper bore 95 of the die 93 the plunger 98 is inserted therein against the illed end 9~ of the elongated billet 89. Referring to Figure 17 pressure is then applied to the plunger 98 which forces all except a terminal portion of the elongated billet 89 through the ex-trusion orifice 97 of the die 93 to form a composite center electrode indicated generally at 100. rhe composite center electrode 100 has the unextruded terminal portion of the elongated billet 89 as a head 101 and a rod 102 extending longi-_9_ 5~
tudinally therefrom. The electrode nead 101 has an upper surface 103 conforming to the shape of the lower surface 99 of the plunger 98, a cylindrical side 104 having a diameter equal to that of the upper bore 95 of the die 93, an~ an under surface 105 conforlning to the shape of the shoulder 96. Although the lower sur-face 99 of the pl~mger 98 is illustrated as beill~ concave, it c-n be of any shape necessary to form the upper surface 103 desired for the electrode head 101.
'l`he composite center electrode lO0 is then removed from the die 93 through the upper bore 95 and is suitable for the desired use without further cold-working or extruding steps.
form an elongated composite billet having closed and filled ends, whereupon the closed end of the elongated composite billet is inserted into a second die having a stepped bore including an upper bore in tYhiCIl the billet fits closely and an e~trusion orifice of red~lced diameter, and all except ~n upper hcaded portion adjacent to the filled end of the elongatecl billet is forced through the extrusion orifice to form the composite center elec~rode. Therefore, the upper headed portion of the composite center electrode does not need shaping because the composite billet was first extruded to the desired diameter.
In the accompanying drawings:
Figure 1 is a partially schematic, vertical sectional view showing a corrosion-resistant metal cup and a right circular cylindrical billet of metal of high thermal conductivity prior to being inserted into the cup in accordance with a previously knowlllnetllod.
Figure 2 is a sectional view showing a composite billet ormed from the cup and billet of Figure 1.
Figure 3 is a partially schematic, vertical sectional view showing the composite billet of Figure 2 inserted into a bore of a die having within the bore an extrusion orifice.
Figure 4 is a sectional view showing an electrode blank formed from the cornposite billet of Figure 3 after all except a terminal portion thereof is forced through the extrusion orifice.
Figure 5 is a partially schematic, vertical sectional view showing a right circular cylindrical billet of corrosion-resistant metal inserted in~o a cavity of a die in accordance with the present invention.
Figure 6 is a sectional view showing a cup ormed by back~extruding the billet of Figure 5.
Figure 7 is a partially schematic, vertical sectional view showing a 5~
right circular cylindrical billet of metal of high thermal conductivity prior to being inserted into ~he cup of Figure 6.
Figure 8 is a sectional view showing the billet of Figure 7 inserted into the cup in Figure 7.
Figure 9 is a partially schematic, vertical sectional view shol~ing the billet and the cup of Figure 8 inserted into a cavity of a die.
Figure 10 is a partially schematic, vertical sectional view showing a composite billet formed from the cup and the billet within the cavity of the die of Figure 9, and inserted into a bore of a die having within the bore an extrusion orifice.
Figure 11 is a sectional view showing an electrode blank formed from the composite billet of Figure 10 after all except an upper headed portion there-of is forced through the extrusion orifice.
Figure 12 is a partially schemat.ic, vertical sectional view showing the electrode blank of Figure 11 positioned in a die having a stepped bore including an upper bore> a shearin~ shoulder, a second shoulder and a lower bore.
Figure 13 is a partially schematic, vertical sectional view showing a composite center electrode formed by shearing the upper headed portion of the electrode blank of Figure 12.
Figure 14 is a partially schematic, vertical sectional view showing a composite billet formed from the cup and the billet within the cavity of the die of Figure 9, and inserted into a bore o a die having within the bore an extru-sion orifice equal in diameter to that of a desired elec~rode head.
Figure 15 is a sectional view showing an elongated composite billet ~ormed by forcing the composite billet of Figure 14 through the extrusion orifice and> thereabove, a second composite billet in a par~ially deformed condition.
--4~
Figure 16 is a partially schematic, vertical sec-tional view showing the elongatec. composite bi]let of Figure 15 inserted into a bore of a d.ie having withill the bore an ex-trusioll ori.Eice.
Fiyure 17 is a sectiollal view showillg a compos.ite cetlte:r electrode :Eol-med ~rom the elongatecl billet o.t l?igu:re 1~ after all except an upper heclded por-tion thereof is forced thro-lgh the extrusion orifice.
Referrring -to E`igure 1, one method for producing composite center electrodes involves first forming a cup 10 from a corrosion-resistant metal, such as nickel. The cup 10 has a closed end 11, walls 12 extending upwardly from the closed end 11 to an open end 13 and a cavity 14 extendi.ng concentrically therein to a lower surface 15. A composite billet is then Eormed by posi-tioning interiorly of the eup 10 a close-Eitting right eireular eylindrical billet 1~, of a metal having a hicJh thermal conductivity, sueh as eopper. The billet 16 fits tightly within the cup walls 12 to form a eomposite billet indicated generally at 17 in Figure 2, having elosed and filled ends 18 and 19. The method fur-ther involves inserting the closed end 18 of the composite billet 17 into a die indicated at 20 in Figure 3, having a stepped bore 21 including an upper bore 22 in whieh the billet 17 fits closely and an extrusion orifice 23 of reduced diameter relative to the upper bore 22. Pressure is then applied to a plunger 24 to force a].l except a terminal portion 25 (Figure 4) of the billet 17 through the extrusion orifiee 23. ~n electrode blank 26 -thus formed has the unextruded terminal portion 25 as an upper headed portion, a lower portion 27 of reduced diameter extending longitudinally therefrom, and a copper core 28 extending therein. After the ~ 5 _ J
~ `~
electrode blank 26 is removed from the die 20, it is suitable for use as a composite center electrode for a spark plug. If desired, howevel-, the upper headed portion 25 can be shaped by cold-workinc3 or furt}ler extrusion into a more desirable e~ectrode~ he~ad con-L`i~uratio~ \n electrc~de assemhly is formed by weldillg a metal rod (not illustrated) to the upper heacled portion 25 of the electrode blank 26. The primary disadvantage of the method just described is the difficulty involved in welding the metal rod to the head 25 because the amount of niclcel remaining after the copper core 28 has been extruded therein is insufficient.
The present invention relates to an improved method Eor producing a composite center eleetrode for a spark plug as described in detail hereinafter.
Referrinc3 to Figure 5, a back-extruder indicated genercllly at 29 comprises a die 30 positioned on a platen 31 and having a right circular bore 32 extending therethrough. The back-extruder 29 also comprises a piston 33 extending through the pla-ten 31 in structural relationship with a floating ejector 34 which closes a lower opening oE the bore 32, and a plunger 35 having a diameter less than that of the bore 32 and insertable therein, and having a lower surface 36. A cavity indicated generally at 37 is Eormed by walls of the bore 32 and an upper surface 38 of the rloating ejector 34.
The first step of the method involves forming a cup from a right eircular cylindrical billet of a corrosion-resistant metal, sueh s niekel or niekel alloy. The eup can be formed by drilling or baek-extrusion, .he latter of which is preferred and comprises the following sub-steps. A right circular cylindrical billet 39 ~- 5a -of nickel alloy having an upper end 40 is sized to fit tightly against the walls o.E -the bore 32 when inserted therein. ~fter the billet 39 is in~serted into the cavity 37 of the bore 32 and super-posed on -tlle upper sur:Eace 38 oE the floatinq e,ec-tor 34, the plunc]er 35 is inserted therein agai.nst the upper end 40 of the billet 39. Pressure is then applied to the pl.unger 35 which pierces the billet 39 and causes back-extrusion there of to form a cup 41 as illustrated in Figure 6. The cup 41 has a closed end 42, walls 43 extending upwardly from the closed end 42 to an open end 44 and a cavity indicated generally at 45 extend~
~ 5b -5~
ing concentrically therein to a lower surface 46 which corresponds to the shape of the lower surace 36 of the plunger 35. After the plunger 35 is extracted from the cavity 45 of the cup 41, pressure is applied to the piston 33 W]liCh causes the floating ejector 34 to force the cup 41 out of the cavity 37 of the die 30.
Ti-e next step of the method involves forming a composite billet.
Referring to Pigure 7, a close-~itting right circular cylindrical billet 47 of a metal having a high thermal conductivity, e. g., copper, is inserted, as indi-cated by an arro~Y, into the open end 44 of the cup 41 and fits closely within the cup walls ~3. The copper billet 47 is compressed within the cavity 45 of the cup 41 into close-fitting relationship with the lower surface 46 thereof, as shown in Figure 8. The copper billet 47 fits tightly within the cup walls 43 adjacent the closed end 42, but terminates short of the open cup end 44 so that the cup walls 43 extend thereabove at the open end 44. Referring to Figure 9, a die indicated at 48 has a cavity 4~ extending longitudinally therein to a lower con-cave surface 50. After the open cup end 44 is inserted into the cavity 49 of the die 48, a plunger 51 is inserted therein against the closed end 42. Force is then applied to the plunger 51 to roll the cup walls 43 adjacent the open cup end 44 radially inwardly to substantially en~lose the billet 47 and to form a composite billet 52 having closed and inwardly turned ends 53 and 54 as illus-trated in Figure 10.
The next step of the method involves forming an elec~rode blank from the composite billet 52. Referring to Figure 10, a forward extruder indicated generally at 55 comprises a die 56 having a stepped bore 57 including an upper bore 58 in which the billet 52 fits closely and an extrusion orifice 59 of re-duced diameter relative to the upper bore 58. The forward-extruder 55 also com-prises a plunger 60 having a diameter equal to that of the upper bore 58 and ~85~5~
insertable therein, and a lower surface 61. After the closed end 53 of the bil-let 52 is inserted into the upper bore 58 of the die 56, the plunger 60 is in-serted therein against the inwardly turned end 54 of the billet 52. Ref~rring to ~igure 11, pressure is then applied to the plunger 60 which forces all ex-cept a terminal portion of the billet 52 thro-lgll the extrusio~ orifice 59 of the die 56 to form an electrode blank indicated generally at 62. The electrode blank 62 has the unextruded terminal portion of the billet 52 as an upper headed portion 63 and a lower portion 6~ o reduced diameter extending longitudinally therefrom, and a copper core 65 extending therein. After the electrode blank 62 is removed from the die 56, it is suitable for use as a composite center electrode for a spark plug. If desired, however, the upper headed portion 63 can be shaped by cold-working) further extruding, or shearing into a more de-sirable electrode head configuration. The latter of these is preferred.
The final step of the method involves shearing and shaping the upper headed portion 63 of the electrode blank 62. Referring to Rigure 12, a shearing and orming apparatus indicated generally at 66 comprises a die 67 having a stepped bore 68 including a right circular upper bore 69 extending to a shearing shoulder 70 of reduced diameter, a central bore below the shearing shoulder 70 and extending to a second shoulder 71, and a lower bore 72 extending rom the second shoulder 71 through the die 67. The first step of the improved method in-volves inserting the electrode blank 62 within the stepped bore 68. When the electrode blank 62 is so inserted, the upper headed portion 63 seats on the shear-ing shoulder 70 and fits closely within the upper bore 69, while the lower por-tion 64 fits closely within the lower bore 72. The shearing and forming appar-atus 66 also comprises a plunger 73 having a diameter subs~antially equal to that of the shearing shoulder 70 and inser~able therethrough9 and a lower sur-face 74.
~L9~
The plunger 73 is inserted concentrically within the upper bore 69 against the upper headed portion 63 of the electrode blank 62. Pressure is ~hen applied to the plunger 73 to force the upper headed portion 63 of the electrode blank 62 past the shearing sho-llder 70, leaving a ring 75 (Figure 13) of excess Inaterial, and against the second shoulder 71 (Figure 12) to form a desired com-posite center electrode indicated generally at 76 (Figure 13). The composite electrode 76 includes a head 77 and the rod 64 of the electrode blank 62 (Figures 11 and 12). The electrode head 77 (Figure 13) has an upper and under surface 78 and 79 conforming to the shape of the lower surface 74 (Figure 12) of the plunger 73 and the second shoulder 71 of the die 67 respectively. Although the lower surface 74 of the plunger 73 is illustrated as being concave, it can be of any shape necessary to form the upper surface 78 (Figure 13) desired for the electrode head 77. The electrode head 77 also has a cylindrical side 80 having a diameter equal to that of the shearing shoulder 70 (Figure 12) of the die 67. The com-posite center electrode 76 (Figure 13) is then removed from the die (Figure 12) through the upper bore 69 and is suitable for the desireduse without further cold-working or extruding steps.
The method includes the additional improvement wherein the composite billet 52 (Figure 10) formed by the cup 41 and the billet 47 within the cavity 49 of the die 48 of Figure 9 is first extruded to ~he desired electrode head dia-meter. The first step of the method involves forming an elongated composite bil-let from the billet 52. Referring to Figure 14, a forward-extruder indicated generally at 81 comprises a die 82 having a stepped bor~ 83 including an upper bore 84 in which the billet 52 fits closely and an extrusion orifice 85 ~f re-duced diameter relative to the upper bore 84andequal to that of the desired el trode head. The forward-extruder 81 also comprises a plunger 86 having a dia-meter equal to that of the upper bore 84 and insertable therein, and a lower surface 87.
After the closed end 53 of the billet 52 is inserted into the upper bore 84 of the die 8~ the plunger 86 is inserted therein against the in~ardly turned end 54 of the billet 52. Pressure is theTI applied to the plunger 86 whic}l forces all except a terminal portion of the billet 52 throug}l the extrusion orifice 85 of the die 82. The plunger 86 is withclrawll from the die 82 and a seconcl billet (not shown) similar to the first billet 52 is inserted therein and supelposed on the inwardly turned encl 54 of the first billet 52. The plunger 86 is then re-inserted into the upper bore 84 of the die 82 against the second billet. Refer-ring to Figure lS pressure is applied to the plunger 86 which compresses the second billet ~o an intermedia~e shape 88 and forces the rer~;n;ng terminal portion of the first billet 52 through the e~trusion orifice to form an elongated composite bille~ indicated generally at 89 and }laving closed and filled ends 90 and 91.
The final step of the laethod involves forming a composite center electrode from the elongated billet 89. Referring to Figure 16 a sec~nd forward-extruder indicated generally at 92 comprises a die 93 having a stepped bore 94 including an upper bore 95 extending to a shoulder 96 and an extrusion oriice 97 of reduced diameter adjacent and below the shoulder 96. The forward-extruder 92 also comprises a plunger 98 having a diameter equal to that of the upper bore 95 and insertable therein and a lower surface 99. After the closed end 90 of the elongated billet 89 is inserted into the upper bore 95 of the die 93 the plunger 98 is inserted therein against the illed end 9~ of the elongated billet 89. Referring to Figure 17 pressure is then applied to the plunger 98 which forces all except a terminal portion of the elongated billet 89 through the ex-trusion orifice 97 of the die 93 to form a composite center electrode indicated generally at 100. rhe composite center electrode 100 has the unextruded terminal portion of the elongated billet 89 as a head 101 and a rod 102 extending longi-_9_ 5~
tudinally therefrom. The electrode nead 101 has an upper surface 103 conforming to the shape of the lower surface 99 of the plunger 98, a cylindrical side 104 having a diameter equal to that of the upper bore 95 of the die 93, an~ an under surface 105 conforlning to the shape of the shoulder 96. Although the lower sur-face 99 of the pl~mger 98 is illustrated as beill~ concave, it c-n be of any shape necessary to form the upper surface 103 desired for the electrode head 101.
'l`he composite center electrode lO0 is then removed from the die 93 through the upper bore 95 and is suitable for the desired use without further cold-working or extruding steps.
Claims (6)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method of forming bimetal electrodes, for spark plugs or the like, comprising forming a first metal into a cup having an open end, a closed end, a cylindrical wall and a central opening which extends a distance Z from the closed end to the open end, forming a right circular cylindrical core from a second and different metal, said core being sized to be received in the central opening in close fitting relationship with the wall there-around, and to extend from the closed end toward the open end a distance less than Z, positioning said core in said central opening thereby forming a composite billet having first and second ends corresponding, respectively, with the open and closed ends of the cup, extruding at least a portion of the composite billet, second end first, through an extrusion orifice of a die with a force applied to the first end of the composite billet by an end of a tool, said force being applied so as to maintain substantial contact between said core and said closed end of the cup while said extrusion is occurring.
2. A method as claimed in claim 1 wherein, prior to extrusion but after the composite billet has been formed, the cup wall at the first end of the composite billet is deformed radially inwardly to close, at least partially, the cup wall around the core.
3. A method as claimed in claim 1 or 2 wherein, prior to the extrusion step but after the composite billet has been formed, the cup and the right circular cylindrical core are forced into close fitting engagement.
4. A method as claimed in claim ? wherein only a portion of the composite billet is extruded and wherein, after extrusion, the diameter of the unextruded portion is reduced.
5. An electrode for spark plugs or the like, comprising a core formed of one metal, such as copper or the like, and an outer surface of a second and different metal completely encap-sulating said core, said electrode being formed by simultaneous extrusion of said core metal and said second metal by a force applied to a inturned end of a cup of said second metal which forcefully closes said inturned end and maintains substantial contact between said closed end of said cup and said core.
6. An electrode for spark plugs or the like, comprising a core formed of one metal, such as copper or the like, and an outer surface of a second metal at least partially encapsulating said core, said electrode being formed by partially extruding a com-posite produced by seating the core metal within a cup shaped body of said second metal having open and closed ends, said composite being partially extruded, closed cup end first, through an extrusion die while simultaneously maintaining substantially complete contact between said closed cup end and the core metal and shaping the unextruded open end of the cup to encapsulate the core at least partially.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000465593A CA1198952A (en) | 1980-05-30 | 1984-10-16 | Method for producing a composite center electrode |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US15488480A | 1980-05-30 | 1980-05-30 | |
| US154,884 | 1980-05-30 |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000465593A Division CA1198952A (en) | 1980-05-30 | 1984-10-16 | Method for producing a composite center electrode |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1198951A true CA1198951A (en) | 1986-01-07 |
Family
ID=22553227
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000378603A Expired CA1198951A (en) | 1980-05-30 | 1981-05-29 | Method for producing a composite center electrode |
Country Status (7)
| Country | Link |
|---|---|
| JP (1) | JPS5757480A (en) |
| BE (1) | BE889012A (en) |
| CA (1) | CA1198951A (en) |
| DE (1) | DE3118793A1 (en) |
| FR (1) | FR2483694A1 (en) |
| GB (1) | GB2076706B (en) |
| IT (1) | IT1142777B (en) |
Families Citing this family (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4904216A (en) * | 1983-09-13 | 1990-02-27 | Ngk Spark Plug Co., Ltd. | Process for producing the center electrode of spark plug |
| US4606730A (en) * | 1983-09-21 | 1986-08-19 | The National Machinery Company | Bimetal electrodes for spark plugs or the like and method of making same |
| US4585421A (en) * | 1983-11-23 | 1986-04-29 | The National Machinery Company | Method of making copper-clad bimetal electrodes for spark plugs |
| JPS61237386A (en) * | 1985-03-11 | 1986-10-22 | チヤンピオン スパーク プラツグ コムパニー | Manufacture of compound center electrode for spark plug |
| US4684352A (en) * | 1985-03-11 | 1987-08-04 | Champion Spark Plug Company | Method for producing a composite spark plug center electrode |
| US5993185A (en) * | 1996-03-21 | 1999-11-30 | Farmacapsulas S.A. | Deck plate assemblies for forming capsules |
| JP5279870B2 (en) * | 2011-01-27 | 2013-09-04 | 日本特殊陶業株式会社 | Spark plug electrode manufacturing method and spark plug manufacturing method |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS56920B2 (en) * | 1972-04-04 | 1981-01-10 | ||
| JPS48103445A (en) | 1972-04-14 | 1973-12-25 | ||
| DE2755120A1 (en) * | 1977-12-10 | 1979-06-13 | Atomic Energy Authority Uk | Spark plug electrode mfr. - by melting metal core to metal sheath |
| GB2024665B (en) * | 1978-07-07 | 1982-08-11 | Ford Motor Co | Spark plug electrode manufacture |
| GB2060454B (en) * | 1979-10-15 | 1983-09-14 | Champion Spark Plug Co | Production of spark plug electrodes |
| NL8101572A (en) | 1980-04-09 | 1981-11-02 | Nat Marking Mach Co | METHOD FOR MANUFACTURING A BIMETAL ELECTRODE |
| US4575343A (en) | 1980-04-09 | 1986-03-11 | The National Machinery Company | Bimetal electrode and method of making same |
-
1981
- 1981-05-05 GB GB8113703A patent/GB2076706B/en not_active Expired
- 1981-05-12 DE DE19813118793 patent/DE3118793A1/en active Granted
- 1981-05-21 JP JP56077321A patent/JPS5757480A/en active Pending
- 1981-05-27 IT IT48542/81A patent/IT1142777B/en active
- 1981-05-27 BE BE0/204939A patent/BE889012A/en not_active IP Right Cessation
- 1981-05-27 FR FR8110578A patent/FR2483694A1/en active Granted
- 1981-05-29 CA CA000378603A patent/CA1198951A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3118793C2 (en) | 1990-05-03 |
| GB2076706A (en) | 1981-12-09 |
| JPS5757480A (en) | 1982-04-06 |
| IT8148542A0 (en) | 1981-05-27 |
| IT1142777B (en) | 1986-10-15 |
| DE3118793A1 (en) | 1982-04-29 |
| FR2483694B1 (en) | 1984-06-29 |
| BE889012A (en) | 1981-09-16 |
| GB2076706B (en) | 1984-06-27 |
| FR2483694A1 (en) | 1981-12-04 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP0086036B1 (en) | Method and apparatus for forming a cylindrical article, in particular an electrical connector | |
| CA1295466C (en) | Composite center electrode for a spark plug and method of producing same | |
| CA1198951A (en) | Method for producing a composite center electrode | |
| EP0426312A2 (en) | Cold-forming dies and cold-forming process | |
| US20160256965A1 (en) | Method of manufacturing a hollow poppet valve | |
| GB2141654A (en) | Method of forming spark plug shells | |
| US4739551A (en) | Hermetic terminal assembly pin and method and apparatus for making the same | |
| CA1169237A (en) | Production of electrodes | |
| CA2276452A1 (en) | Resistance welding electrode and process for making | |
| CA1178653A (en) | Method for producing a composite center electrode and an electrode | |
| US4526551A (en) | Production of electrodes | |
| EP1040887A4 (en) | Method of producing sintered body | |
| DE69929893T2 (en) | ELECTROCHEMICAL CELL WITH ONE OF THE LID ELECTRICALLY INSULATED COLLECTOR | |
| US4606730A (en) | Bimetal electrodes for spark plugs or the like and method of making same | |
| CA1198952A (en) | Method for producing a composite center electrode | |
| US6792786B2 (en) | Fabrication method of metal shell of spark plug | |
| GB2069378A (en) | Production of spark plug electrodes | |
| JPS6166018A (en) | Manufacture of housing of glow plug for diesel engine | |
| CN211613955U (en) | Pipe with folded edge | |
| US4585421A (en) | Method of making copper-clad bimetal electrodes for spark plugs | |
| EP0566803A1 (en) | Method for the manufacture of extrusion dies, and dies obtained therefrom | |
| JPH0489153A (en) | Cold and warm forging method for cylindrical body | |
| JP3863606B2 (en) | Battery terminal manufacturing method and apparatus thereof | |
| CA1203510A (en) | Spark plug electrode and its method of manufacture | |
| JP3226947B2 (en) | Method and forming apparatus for forming second layer of green compact on cylindrical member |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |