US3300822A - Die casting plunger piston ring - Google Patents

Die casting plunger piston ring Download PDF

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Publication number
US3300822A
US3300822A US452658A US45265865A US3300822A US 3300822 A US3300822 A US 3300822A US 452658 A US452658 A US 452658A US 45265865 A US45265865 A US 45265865A US 3300822 A US3300822 A US 3300822A
Authority
US
United States
Prior art keywords
ring
pressure
groove
plunger
piston
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 - Lifetime
Application number
US452658A
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English (en)
Inventor
William E Thompson
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Motors Liquidation Co
Original Assignee
Motors Liquidation Co
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Motors Liquidation Co filed Critical Motors Liquidation Co
Priority to US452658A priority Critical patent/US3300822A/en
Priority to GB17473/66A priority patent/GB1070180A/en
Priority to DEP1272A priority patent/DE1272492B/de
Application granted granted Critical
Publication of US3300822A publication Critical patent/US3300822A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B22D17/2015—Means for forcing the molten metal into the die
    • B22D17/203—Injection pistons

Definitions

  • This invention relates to improvements in pistons for hot chamber die casting and is particularly concerned with providing for lubrication between the piston ring and cylinder wall during the high temperatures and pressure conditions encountered in the die casting process.
  • molten metal is forced into the die cavity under the pressure exerted by a piston or plunger.
  • the piston and pressure chamber are submerged in a reservoir of hot molten metal and the molten charge or shot flows into the chamber through inlet ports.
  • the piston on its pressure stroke closes the ports and forces the entrapped molten metal into the die developing a pressure in the vicinity of 2500 p.s.i. or more. This pressure is maintained on the metal in the die cavity until it has solidified.
  • the piston is then lifted to an intermediate position still blocking the inlet ports of the shot cylinder. This creates a vacuum under the shot plunger so that the molten metal is withdrawn from the sprue. At this point the dies are opened and the piston is raised further opening the inlet ports to the pressure cylinder.
  • FIGURE 1 shows a sectional elevation view of a portion of a hot chamber die cast machine including the furnace, reservoir, molten metal, gooseneck, extension nozzle, pressure cylinder, and shot piston in raised position.
  • FIGURE 2 is an enlarged fragmentary vertical view of the piston and three piston rings.
  • FIGURE 3 is an enlarged fragmentary vertical view of the subject piston ring and surrounding piston and pressure cylinder wall.
  • FIGURE 1 The gooseneck injection apparatus for charging the molten metal into the die cavity of a hot chamber die casting machine is shown in FIGURE 1.
  • a piston 10 operates reciprocally in a vertically disposed pressure cylinder 11.
  • the cylinder 11 is connected to the sprue (not shown) through a gooseneck 12 and extension nozzle 13.
  • the piston 10, cylinder 11, and gooseneck 12 are immersed in a molten metal bath in a reservoir 14.
  • the metal is heated by means of a furnace 15.
  • the piston is in the fully raised position (as shown in FIG- URE 1) the molten metal may flow into the pressure cylinder 11 and the gooseneck 12 through an inlet port 16.
  • the pressure and vacuum seal is maintained by one or more piston rings 17.
  • the rings are split at 18 and are located in axially spaced grooves 19 in the piston 10. These grooves 19 are located in the cylindrical surface of the piston and normally lie in a plane perpendicular to the longitudinal axis of the piston.
  • the axial dimension 20 of the groove is slightly greater than the thickness 21 of the piston ring.
  • the diameter of the bottom of the groove is less than the inside diameter of the piston ring.
  • the advantage of the subject invention is that the piston rings 17, as best seen in FIGURE 3, acting in combination with the plunger and the cylinder 11, are tapered 24.
  • a given ring 17 has its outside edge on the pressure side of the ring chamfered 24.
  • the angle of the chamfer from the longitudinal axis of its piston carrier is in the range of 5 to 20. It has been found that in zinc die casting an angle of is optimum.
  • the function of this chamfer is to channel or wedge a thin film of molten metal between the cylinder and surface 23 of the piston ring 17 and the wall of the pressure cylinder 11 thereby effectively lubricating the bearing surfaces and markedly increasing its seal characteristics.
  • the ring in the combination of the subject invention can vary in thickness 21, but actually need be no more than approximately 4 inch in thickness.
  • the preferred embodiment as described uses three thin rings because it has been observed that a number of thin rings are more elfective than a single thick one in maintaining the seal on the vacuum stroke.
  • the desired depth of the chamfer 25 is a function of the angle of the chamfer and the thickness of the ring 21. However, the depth normally would not be greater than and in the case of .a ring A1" in thickness 21 an effective chamfer depth 25 is 0.030".
  • the chamfered ring must, of course, have sufiicient cylindrical surface 23 to seal against the pressure cylinder wall 11.
  • a pressure cylinder having an inlet port, a shot plunger reciprocably operable within said cylinder and having a circumferential groove in the cylindrical surface thereof disposed perpendicularly to the longitudinal axis of said plunger, and a resilient expandable split piston ring in said groove, said ring having an annular chamfer on the outside diameter of the pressure side whereby molten metal is wedged between the outer cylindrical surface of said ring and the cylinder wall during the pressure stroke of said plunger, the angle of said chamfer being on the range of about 5 to said groove being of greater axial thickness than said ring and the inner diameter of said groove being smaller than the inner diameter of said ring whereby the pressurized molten metal flows into said groove between the base of said groove and the inner side of said ring to exert a sealing pressure on said ring against said cylinder wall during said pressure stroke of said plunger.
  • a vertically disposed pressure cylinder having an inlet port, a shot plunger reciprocably operable within said cylinder and having a circumferential groove in the cylinder surface thereof disposed perpendicularly to the longitudinal axis of said plunger, and a resilient expandable split piston ring in said groove, said ring having an annular chamfer on the outside diameter of the pressure side whereby molten metal is wedged between the outer cylindrical surface of said ring and the cylinder wall during the pressure stroke of said plunger, the angle of said chamfer being in the range of about 5 to 20, said groove being of greater axial thickness than said ring and the inner diameter of said groove being smaller than the inner diameter of said ring where by the pressurized molten metal flows into said groove between the base of said groove and the inner side of said ring to exert a sealing pressure on said ring against said cylinder wall during said pressure stroke of said plunger.
  • a vertically disposed pressure cylinder having an inlet port, a shot plunger reciprocably operable within said cylinder and having a circumferential groove in the cylindrical surface thereof disposed perpendicularly to the lon gitudinal axis of said plunger, and a resilient expandable split piston ring in said groove, said ring having an annular chamfer on the outside diameter of the pressure side whereby molten metal is wedged between the outer cylindrical surface of said ring and the cylinder wall during the pressure stroke of said plunger, the angle of said chamfer being about 15, said groove being of greater axial thickness than said ring and the inner diameter of said groove being smaller than the inner diameter of said ring whereby the pressurized molten metal flows into said groove between the base of said groove and the inner side of said ring to exert a sealing pressure on said ring against said cylinder wall during said pressure stroke of said plunger.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)
US452658A 1965-05-03 1965-05-03 Die casting plunger piston ring Expired - Lifetime US3300822A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US452658A US3300822A (en) 1965-05-03 1965-05-03 Die casting plunger piston ring
GB17473/66A GB1070180A (en) 1965-05-03 1966-04-21 Die casting machines
DEP1272A DE1272492B (de) 1965-05-03 1966-04-22 Druckgiessmaschine

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US1272492XA 1965-05-03 1965-05-03
US452658A US3300822A (en) 1965-05-03 1965-05-03 Die casting plunger piston ring

Publications (1)

Publication Number Publication Date
US3300822A true US3300822A (en) 1967-01-31

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
US452658A Expired - Lifetime US3300822A (en) 1965-05-03 1965-05-03 Die casting plunger piston ring

Country Status (2)

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US (1) US3300822A (de)
DE (1) DE1272492B (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3815663A (en) * 1972-02-18 1974-06-11 Connor J O Die casting apparatus
US4595044A (en) * 1984-04-10 1986-06-17 Vsi Corporation Die casting apparatus
US4886107A (en) * 1986-02-28 1989-12-12 Zecman Kenneth P Piston for cold chamber
US4899804A (en) * 1989-02-21 1990-02-13 Hammerer Norman L Plunger tip for cold chamber die cast machine
EP0368573A2 (de) * 1988-11-08 1990-05-16 Electrovert Ltd. Giessverfahren und Vorrichtung für niedrig schmelzende Metallegierungen
US5001871A (en) * 1988-05-27 1991-03-26 Societe d'Etude de Realisation et de Diffusion Industrielles - SERDI Machine for precision machining, with a rod for the determination of the practical mean axis of a hole of cylindrical general contour
EP1197279A2 (de) * 2000-10-13 2002-04-17 Copromec S.r.l. Druckgiesskolben für Kaltkammer-Druckgiessmaschine

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3248423A1 (de) * 1982-12-28 1984-06-28 Gebrüder Bühler AG, Uzwil Verfahren zum druckgiessen und druckgiessmaschine zur ausfuehrung dieses verfahrens
EP0901852B1 (de) * 1997-09-09 2002-07-17 André Müller Kolben für eine Warmkammer-Druckgiessmachine
EP0936010A1 (de) * 1998-02-12 1999-08-18 Didier-Werke Ag Verfahren zum Vergiessen von Metallen unter Druck und Vorrichtung zur Durchführung des Verfahrens
DE20309181U1 (de) * 2003-06-13 2004-10-28 Allper Ag Mehrteiliger Kolben für eine Kaltkammer-Druckgießmaschine

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1764815A (en) * 1927-12-03 1930-06-17 Williams Judson Piston ring
US2913269A (en) * 1956-06-18 1959-11-17 Boeing Co High pressure high temperature metal seals

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1764815A (en) * 1927-12-03 1930-06-17 Williams Judson Piston ring
US2913269A (en) * 1956-06-18 1959-11-17 Boeing Co High pressure high temperature metal seals

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3815663A (en) * 1972-02-18 1974-06-11 Connor J O Die casting apparatus
US4595044A (en) * 1984-04-10 1986-06-17 Vsi Corporation Die casting apparatus
US4886107A (en) * 1986-02-28 1989-12-12 Zecman Kenneth P Piston for cold chamber
US5001871A (en) * 1988-05-27 1991-03-26 Societe d'Etude de Realisation et de Diffusion Industrielles - SERDI Machine for precision machining, with a rod for the determination of the practical mean axis of a hole of cylindrical general contour
EP0368573A2 (de) * 1988-11-08 1990-05-16 Electrovert Ltd. Giessverfahren und Vorrichtung für niedrig schmelzende Metallegierungen
EP0368573A3 (de) * 1988-11-08 1991-05-29 Electrovert Ltd. Giessverfahren und Vorrichtung für niedrig schmelzende Metallegierungen
US4899804A (en) * 1989-02-21 1990-02-13 Hammerer Norman L Plunger tip for cold chamber die cast machine
EP1197279A2 (de) * 2000-10-13 2002-04-17 Copromec S.r.l. Druckgiesskolben für Kaltkammer-Druckgiessmaschine
EP1197279A3 (de) * 2000-10-13 2002-04-24 Copromec S.r.l. Druckgiesskolben für Kaltkammer-Druckgiessmaschine

Also Published As

Publication number Publication date
DE1272492B (de) 1968-07-11

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