Casting tool and method for producing a piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11623272-B2
Application number	US-201515505096-A
Country	US
Kind code	B2
Filing date	Jul 21, 2015
Priority date	Aug 20, 2014
Publication date	Apr 11, 2023
Grant date	Apr 11, 2023

Abstract

A casting tool for a piston may include a casting mold for forming a piston part from a casting melt and a casting head including a feeder for feeding the casting melt into the casting mold. The casting head may include a ring-shaped groove, and the groove may include an inner groove flank for forming the casting melt into a circumferential, ring-shaped sealing rib such that an inner rib flank of the sealing rib rests with a sealing effect against the inner groove flank when the casting melt solidifies in the groove. Additionally or alternatively, the casting head may include a ring-shaped collar, and the collar may include an outer collar flank for forming the casting melt to provide a circumferential, ring-shaped sealing groove such that an outer groove flank of the sealing groove rests with a sealing effect against the outer collar flank when the casting melt solidifies.

First claim

The invention claimed is:

1. A method for producing a piston, comprising:
introducing a casting melt into a casting head of a casting tool via an inlet;
casting the casting melt, wherein casting the casting melt includes at least one of:
forming the casting melt into a ring-shaped sealing rib via a ring-shaped groove of the casting tool that extends around a feeder of a thermally insulating material in the casting head at a radial distance therefrom, such that upon solidification of the casting melt an inner rib flank of the sealing rib rests with a sealing effect against an inner groove flank of the groove, wherein forming the casting melt into the ring-shaped sealing rib includes contacting the casting melt with the inner groove flank having a slope angle of 10° to 15° relative to a perpendicular to a surface of the casting head to facilitate sealing the casting melt along the inner rib flank; and
forming the casting melt to provide a ring-shaped sealing groove via a ring-shaped collar of the casting tool that extends around the feeder in the casting head at a radial distance therefrom, such that upon solidification of the casting melt an outer groove flank of the sealing groove rests with a sealing effect against an outer collar flank of the collar, wherein forming the casting melt into the ring-shaped sealing groove includes contacting the casting melt with the outer collar flank having a slope angle of 10° to 15° relative to a perpendicular to a surface of the casting head to facilitate sealing the casting melt along the outer groove flank;

inserting at least one porous insert into a casting mold of the casting tool, and infiltrating the at least one porous insert with the casting melt via exerting a pressure on the casting melt, wherein infiltrating the at least one porous insert includes providing a negative pressure via suction lines leading to the at least one porous insert to facilitate infiltration with the casting melt; and
guiding the feeder in the casting head via a sleeve coupled to the casting head, the sleeve extending through the casting head from an interior of the casting mold outwards beyond the casting head, and wherein a pressurized gas line is coupled to the sleeve in a pressure tight manner for pressurizing the casting melt.

2. The method as claimed in claim 1 , further comprising cooling at least one of the groove and the collar by circulating a cooling medium through at least one passage arranged in the casting head in a region of the at least one of the groove and the collar.

3. The method as claimed in claim 1 , further comprising compressing the casting melt within the casting head.

4. The method as claimed in claim 3 , wherein compressing the casting melt includes providing a casting pressure of between 0.35 bar and 20 bar after filling the casting mold with the casting melt and after partial solidification of the casting melt.

5. The method as claimed in claim 3 , wherein compressing the casting melt includes pressurizing the casting mold via the pressurized gas line that opens into the feeder to exert the pressure on the casting melt for infiltrating the at least one insert with the casting melt while providing the negative pressure via the suction lines to facilitate infiltration.

6. The method as claimed in claim 1 , wherein the casting melt includes molten aluminum containing 10% to 14% by weight of silicon and at least one of up to 6% by weight of copper, up to 3% by weight of nickel and up to 1% by weight of magnesium.

7. The method as claimed in claim 6 , wherein a percentage of impurities present in the casting melt, defined by one or more low-melting elements with a melting point <490° C., is in each case less than 0.01%.

8. The method as claimed in claim 1 , wherein casting the casting melt includes one of gravity diecasting and low-pressure diecasting.

9. The method as claimed in claim 1 , wherein the casting melt includes molten aluminum containing 10% to 14% by weight of silicon.

10. The method as claimed in claim 1 , wherein casting the casting melt includes forming the casting melt into the ring-shaped sealing rib via the ring-shaped groove, and further including compressing the casting melt via a pressurized gas within the casting head.

11. The method as claimed in claim 1 , wherein casting the casting melt includes forming the casting melt to provide the ring-shaped sealing groove via the ring-shaped collar, and further including compressing the casting melt via a pressurized gas within the casting head.

12. The method as claimed in claim 5 , wherein introducing the casting melt into the casting head includes communicating a free space within the feeder with an external environment via the pressurized gas line for pressure equalization.

13. The method as claimed in claim 1 , wherein casting the casting melt includes both of forming the casting melt into the ring-shaped sealing rib via the ring-shaped groove and forming the casting melt to provide the ring-shaped sealing groove via the ring-shaped collar.

14. The method as claimed in claim 13 , wherein the ring-shaped collar is disposed on the casting head radially inwards of the ring-shaped groove, and wherein the ring- shaped collar is arranged separately from the feeder.

15. A method for producing a piston, comprising:
introducing a casting melt into a casting head of a casting tool via an inlet;
casting the casting melt, wherein casting the casting melt includes at least one of:
forming the casting melt into a ring-shaped sealing rib via a ring-shaped groove of the casting tool that extends around a feeder in the casting head at a radial distance therefrom, wherein forming the casting melt into the ring-shaped sealing rib via the ring-shaped groove includes contacting the casting melt with an inner groove flank of the ring-shaped groove having a slope angle of between 3° and 20° relative to a perpendicular to a surface of the casting head to facilitate sealing along the inner groove flank and an inner rib flank of the sealing rib upon solidification of the casting melt; and
forming the casting melt to provide a ring-shaped sealing groove via a ring-shaped collar of the casting tool that extends around the feeder in the casting head at a radial distance therefrom, wherein forming the casting melt to provide the ring-shaped sealing groove via the ring-shaped collar includes contacting the casting melt with an outer collar flank of the ring-shaped collar having a slope angle of between 3 ° and 20 ° relative to a perpendicular to a surface of the casting head to facilitate sealing along the outer collar flank and an outer groove flank of the sealing groove upon solidification of the casting melt; and
guiding the feeder in the casting head via a sleeve coupled to the casting head, the sleeve extending through the casting head from an interior of the casting mold outwards beyond the casting head.

16. The method as claimed in claim 15 , wherein casting the casting melt includes both of forming the casting melt into the ring-shaped sealing rib via the ring-shaped groove and forming the casting melt to provide the ring-shaped sealing groove via the ring-shaped collar, and wherein the ring-shaped collar is arranged separately from the feeder.

Assignees

• Mahle Int Gmbh
• Mahle Inernational Gmbh

Inventors

• Rotmann Udo
• Gaissert Juergen
• Ruehle Martin

Classifications

• B22C9/088 Primary

  Feeder heads · CPC title

• B22D15/02 Primary

  of cylinders, pistons, bearing shells or like thin-walled objects · CPC title

• B22D25/02

  by its peculiarity of shape; of works of art {(cylinders, pistons B22D15/02)} · CPC title

• B22D27/13

  making use of gas pressure · CPC title