Piston for an internal combustion engine

Patent metadata

Field	Value
Publication number	US-11492997-B2
Application number	US-202117378654-A
Country	US
Kind code	B2
Filing date	Jul 16, 2021
Priority date	Jul 17, 2020
Publication date	Nov 8, 2022
Grant date	Nov 8, 2022

Abstract

A piston for an internal combustion engine may include a ring belt, a groove, and an additional groove. The ring belt may extend along an axial direction. The groove may be arranged on the outer circumference of the ring belt and may be configured to receive an oil scraper ring. The additional groove may be arranged on the outer circumference spaced apart from the groove with respect to the axial direction. The additional groove may include a first groove side axially facing away from the groove and a second groove side axially facing the groove. The first groove side may include an axial step.

First claim

The invention claimed is:

1. A piston for an internal combustion engine, comprising:
a ring belt extending along an axial direction;
a groove arranged on an outer circumference of the ring belt, the groove configured to receive an oil scraper ring;
an additional groove arranged on the outer circumference spaced apart from the groove with respect to the axial direction, the additional groove including a first groove side axially facing away from the groove and a second groove side axially facing the groove;
wherein the first groove side includes an axial step;
wherein the axial step includes an axially extending first step portion and a radially extending second step portion;
wherein the groove and the additional groove are axially separated from one another via a radially protruding ring rib; and
wherein the first step portion and a radially outward facing end of the ring rib are substantially coplanar.

2. The piston according to claim 1 , wherein a first side height of the first groove side measured along a radial direction is greater than a second side height of the second groove side measured along the radial direction.

3. The piston according to claim 2 , wherein:
the first groove side includes a radially inner side portion and a radially outer side portion, the radially inner side portion merging via the axial step into the radially outer side portion in a radially outward direction; and
a portion height of the radially inner side portion measured along the radial direction is equal to the second side height of the second groove side.

4. The piston according to claim 1 , wherein a radius of the ring belt measured along the radial direction is smaller in the ring rib than in a second axial portion which on a side facing away from the groove axially follows the additional groove.

5. The piston according to claim 4 , wherein the ring rib extends circumferentially around the outer circumference of the ring belt.

6. The piston according to claim 5 , wherein the ring rib includes at least one oil channel that fluidically connects the groove with the additional groove.

7. The piston according to claim 1 , wherein the first step portion merges at a 90° angle into the second step portion.

8. The piston according to claim 7 , wherein:
the first groove side includes a radially inner side portion and a radially outer side portion;
the radially inner side portion includes the second step portion; and
the first step portion, via a rounding, merges into the radially outer side portion.

9. The piston according to claim 8 , wherein the rounding has an inner radius of 0.25 to 1.0 mm.

10. The piston according to claim 1 , wherein the additional groove further includes a groove bottom extending in the axial direction between the first groove side and the second groove side.

11. The piston according to claim 10 , wherein a distance measured on the outer circumference along the axial direction between the first groove side and the second groove side is greater than an extension of the groove bottom measured along the axial direction.

12. The piston according to claim 10 , wherein a transition from the groove bottom into at least one of the first groove side and the second groove side is formed by a rounding.

13. The piston according to claim 1 , wherein:
the additional groove further includes a groove bottom extending in the axial direction between the first groove side and the second groove side;
the first groove side includes a radially outer side portion that merges into the first step portion via a first rounded transition; and
the second step portion (i) defines a radially inner side portion of the first groove side and (ii) merges into the groove bottom via a second rounded transition.

14. The piston according to claim 13 , wherein at least one oil channel extends from the groove to the additional groove at least partially through the ring rib, the groove and the additional groove in fluid communication with one another via the at least one channel.

15. The piston according to claim 1 , wherein:
the first groove side includes a radially inner side portion and a radially outer side portion;
the radially inner side portion merges via the axial step into the radially outer side portion in a radially outward direction; and
the radially inner side portion and the radially outer side portion are structured conically.

16. The piston according to claim 15 , wherein at least one of (i) a conical surface of the radially inner side portion and (ii) a conical surface of the radially outer side portion extends obliquely relative to the axial direction and defines an angle of 45° or more relative to the axial direction.

17. An internal combustion engine, comprising:
a piston;
a cylinder having a cylinder running surface;
the piston including:
a ring belt extending along an axial direction;
a groove arranged on an outer circumference of the ring belt, the groove configured to receive an oil scraper ring;
an additional groove arranged on the outer circumference spaced apart from the grove with respect to the axial direction, the additional groove including a first groove side axially facing away from the groove and a second groove side axially facing the groove;
the first groove side including an axial step;

wherein the piston is disposed in the cylinder and moveably guided therein such that a first axial portion of the ring belt, which is arranged between the groove and the additional groove is disposed spaced apart from the cylinder running surface forming an intermediate space therebetween;
wherein the axial step is formed by an axially extending first step portion that merges at a 90° angle into a radially extending second step portion;
wherein the first groove side includes a radially inner side portion and a radially outer side portion;
wherein the radially inner side portion includes the second step portion; and
wherein the first step portion merges into the radially outer side portion via a rounding.

18. The internal combustion engine according to claim 17 , wherein:
the groove and the additional groove are axially separated from one another via a radially protruding ring rib; and
the first step portion and a radially outward facing end of the ring rib are substantially coplanar.

19. A method for producing a piston, comprising:
providing a piston blank having a ring belt extending along an axial direction and a groove configured to receive an oil scraper ring, the groove arranged on an outer circumference of the ring belt;
producing, via removing piston material, an additional groove on the outer circumference of the ring belt disposed spaced apart from the groove with respect to the axial direction, the additional groove including a first groove side axially facing away from the groove and a second groove side axially facing the groove; and
creating an axial step on the first groove side via simultaneously removing piston material in the additional groove and in an axial region of the ring belt disposed between the groove and the additional groove.

20. The method according to claim 19 , wherein the axial step is created such that a radius of the piston in the axial region of the ring belt disposed between the groove and the additional groove is the same as in the axial step.

Assignees

• Mahle Int Gmbh

Inventors

• Bischofberger Ulrich
• Braig Ralf
• Schreer Kai
• Stefan Ioan

Classifications

• F02F3/28 Primary

  Other pistons with specially-shaped head · CPC title

• F02F3/00 Primary

  Pistons · CPC title

• F16J9/22

  Rings for preventing wear of grooves or like seatings · CPC title

• F02F2003/0007

  Monolithic pistons; One piece constructions; Casting of pistons · CPC title

• F16J1/08

  Constructional features providing for lubrication · CPC title