Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11274747-B2
Application number	US-202016938907-A
Country	US
Kind code	B2
Filing date	Jul 24, 2020
Priority date	Jul 25, 2019
Publication date	Mar 15, 2022
Grant date	Mar 15, 2022

Abstract

A piston for an internal combustion engine may include at least one oil ring groove configured to receive an oil scraper ring. The at least one oil ring groove may have an upper groove flank, a lower groove flank, and a groove base. The at least one oil ring groove may be structured to be asymmetrical and deeper in a radial direction in a region of the lower groove flank. The piston may also include an oil outflow channel structured and arranged to fluidically communicate with an oil collecting chamber disposed in a spine of the oil scraper ring. A connecting point between at least one of (i) the at least one oil ring groove and the oil outflow channel, and (ii) the oil collecting chamber and the oil outflow channel may be disposed exclusively in the lower groove flank.

First claim

The invention claimed is:

1. A piston for an internal combustion engine, comprising:
at least one oil ring groove configured to receive an oil scraper ring, the at least one oil ring groove having an upper groove flank facing toward a piston crown, a lower groove flank averted from the piston crown, and a groove base;
the at least one oil ring groove structured to be asymmetrical and deeper in a radial direction in a region of the lower groove flank;
an oil outflow channel structured and arranged to fluidically communicate with an oil collecting chamber disposed in a spine of the oil scraper ring;
wherein a connecting point between at least one of (i) the at least one oil ring groove and the oil outflow channel, and (ii) the oil collecting chamber and the oil outflow channel is disposed exclusively in the lower groove flank and spaced apart from a corner of the at least one oil ring groove that connects the lower groove flank and the groove base;
the upper groove flank and the lower groove flank each include a finish-machined surface disposed only in a region which comes into contact with the oil scraper ring when the oil scraper ring is received in the at least one oil ring groove; and
the upper groove flank, the lower groove flank, and the groove base each have a pre-machined surface in a region of the oil collecting chamber.

2. The piston according to claim 1 , wherein the oil outflow channel extends parallel to a piston axis.

3. The piston according to claim 1 , wherein the oil outflow channel extends obliquely with respect to a piston axis and is obliquely connected to the lower groove flank.

4. The piston according to claim 1 , wherein the oil outflow channel extends orthogonally with respect to a piston axis.

5. The piston according to claim 1 , wherein the upper groove flank includes a shoulder projecting into the at least one oil ring groove, the shoulder structured and arranged as a stop which limits a protrusion depth of the oil scraper ring into the at least one oil ring groove.

6. The piston according to claim 1 , wherein the groove base extends obliquely with respect to a piston axis.

7. The piston according to claim 1 , wherein the groove base includes, in a lower inner region, a radially inwardly directed depression.

8. The piston according to claim 1 , wherein:
the oil outflow channel extends parallel to a piston axis; and
the oil outflow channel extends orthogonally with respect to the lower groove flank.

9. The piston according to claim 1 , wherein:
the oil outflow channel extends obliquely with respect to a piston axis;
the oil outflow channel extends obliquely with respect to the lower groove flank; and
the oil outflow channel is obliquely connected to the lower groove flank.

10. The piston according to claim 1 , wherein:
the oil outflow channel extends orthogonally with respect to a piston axis; and
the oil outflow channel extends outward in the radial direction in the lower groove flank.

11. The piston according to claim 1 , wherein the groove base extends between the lower groove flank and the upper groove flank in a direction that is oblique relative to a piston axis, the lower groove flank, and the upper groove flank.

12. The piston according to claim 1 , wherein:
a second corner of the at least one oil ring groove connects upper groove flank and the groove base; and
the groove base extends linearly from the corner to the second corner in a direction that is oblique relative to a piston axis, the lower groove flank, and the upper groove flank.

13. The piston according to claim 1 , wherein the connecting point is substantially planar and does not form a three-dimensional edge structure.

14. A method for producing a piston, comprising:
drilling an oil outflow channel into a body of the piston;
forming an asymmetrical oil ring groove in the body of the piston, the oil ring groove configured to receive an oil scraper ring, the oil ring groove having a groove base, an upper grove flank and a lower groove flank, the upper groove flank facing toward a piston crown, the lower groove flank averted from the piston crown, the oil ring groove configured to be deeper in a radial direction in a region of the lower groove flank;
providing, exclusively in the lower groove flank, a communicating connecting point between at least one of (i) the oil ring groove and the oil outflow channel, and (ii) the oil outflow channel and an oil collecting chamber disposed in a spine of the oil scraper ring;
deburring the connecting point via a chip-removing tool and a grinding tool; and
wherein the oil outflow channel is structured and arranged to fluidically communicate with the oil collecting chamber of the oil scraper ring.

15. The method according to claim 14 , further comprising finish-machining the upper groove flank and the lower groove flank such that (i) the upper groove flank and the lower groove flank have a finish-machined surface only in a region which comes into contact with the oil scraper ring when the oil scraper ring is received in the oil ring groove, and (ii) the upper groove flank, the lower groove flank, and the groove base have a surface in a region of the oil collecting chamber that remains pre-machined.

16. The method according to claim 14 , wherein providing the connecting point includes forming the connecting point in the lower groove flank spaced apart from a corner of the at least one oil ring groove that connects the lower groove flank and the groove base.

17. A piston for an internal combustion engine, comprising:
a piston crown;
an upper groove flank;
a lower groove flank disposed further from the piston crown than the upper groove flank;
a groove base extending between and connecting the upper groove flank and the lower groove flank;
a circumferentially extending oil ring groove defined by the upper groove flank, the lower groove flank, and the groove base, the oil ring groove opening in a radially outward direction;
the oil ring groove having a greater radial depth in a region of the lower groove flank than in a region of the upper groove flank such that the oil ring groove is asymmetrical;
an oil outflow channel structured and arranged to fluidically communicate with an oil collecting chamber disposed in a spine of an oil scraper ring arrangeable within the oil ring groove;
wherein a connecting point between the oil ring groove and the oil outflow channel is disposed exclusively in the lower groove flank;
wherein the upper groove flank and the lower groove flank each include a finish-machined surface disposed only in a region which comes into contact with the oil scraper ring when the oil scraper ring is received in the oil ring groove; and
wherein the upper groove flank, the lower groove flank, and the groove base each have a pre-machined surface in a region of the oil collecting chamber when the oil scraper ring is received in the oil ring groove.

18. The piston according to claim 17 , wherein the lower groove flank extends further in a radially inward direction than the upper groove flank such that the groove base extends transversely relative to a piston axis.

19. The piston according to claim 17 , further comprising a piston body, wherein:
the oil ring groove is disposed in an outer circumferential surface of the piston body; and
the oil outflow channel extends from the lower groove flank to the outer circumferential surface of the piston body.

Assignees

• Mahle Int Gmbh

Inventors

• Licht Philipp
• Scharp Rainer

Classifications

• F16J9/00 Primary

  Piston-rings {, e.g. non-metallic piston-rings}, seats therefor; Ring sealings of similar construction (other sealings between pistons and cylinders F16J3/06, F16J15/16 {; manufacture of piston-rings B23P15/06, B23P15/08}; tools for mounting or removing piston-rings or the like B25B; piston sealing arrangements on brake master cylinders B60T11/236 {; sealing provided on pump pistons F04B53/143}) · CPC title

• F16J9/062 Primary

  Coiled spring along the entire circumference · CPC title

• F16J1/09

  with means for guiding fluids (F16J1/08 takes precedence) · CPC title

• F16J9/20 Primary

  Rings with special cross-section (L-section rings F16J9/02); Oil-scraping rings {(F16J9/06 takes precedence)} · CPC title

• F16J9/06

  using separate springs {or elastic elements} expanding the rings; Springs therefor {; Expansion by wedging} · CPC title