Piston for an internal combustion engine

Abstract

A piston for an internal combustion engine may include a piston body including a piston skirt, a piston head, and a pocket. The piston head may include a cooling channel for receiving a cooling medium. The cooling channel may be open on a side facing away from a piston crown. The piston may also include at least one cooling channel cover at least partially closing the cooling channel, and a piston pin boss having a boss bore configured to accommodate a piston pin. The piston may further include a piston pin lubricating channel fluidically connected to the cooling channel and extending in a direction of the piston pin. The pocket may at least partially define the piston pin lubricating channel. The at least one cooling channel cover may have at least one lug that is offset radially inward and may, together with the pocket, define the piston pin lubricating channel.

Claims

1. A piston for an internal combustion engine, comprising: a piston body including a piston skirt and a piston head; the piston head including an at least partially circumferential cooling channel for receiving a cooling medium, the cooling channel open on a side facing away from a piston crown; at least one cooling channel cover at least partially closing the cooling channel; a piston pin boss having a boss bore configured to accommodate a piston pin; a piston pin lubricating channel fluidically connected to the cooling channel and extending in a direction of the piston pin; a pocket disposed on the piston body, the pocket at least partially defining the piston pin lubricating channel; and wherein the at least one cooling channel cover has at least one lug that is offset radially inward and, together with the pocket, defines the piston pin lubricating channel.

2. The piston as claimed in claim 1, wherein the piston pin lubricating channel is aligned such that the cooling medium flowing therethrough impinges on at least one of the piston pin boss and the piston pin.

3. The piston as claimed in claim 1, wherein the at least one cooling channel cover is structured as a two-part sheet-metal ring having at least one cooling medium inlet opening and at least one cooling medium outlet opening.

4. The piston as claimed in claim 1, wherein: a second pocket is disposed on the piston body spaced apart by 180 in a circumferential direction from the pocket; and at least one lug includes two lugs spaced apart by 180 in the circumferential direction and offset radially inward.

5. The piston as claimed in claim 1, wherein the at least one cooling channel cover is clamped between an annular wall of the piston head and an annular rib of the piston head.

6. The piston as claimed in claim 1, wherein the at least one cooling channel cover has at least one radial longitudinal section which is deep drawn on a side facing away from the piston crown.

7. The piston as claimed in claim 1, wherein the at least one cooling channel cover includes a drip edge on a radially inner longitudinal end, the drip edge projecting over at least one piston pin.

8. The piston as claimed in claim 1, wherein at least one of: the piston is one of a steel piston and a cast piston; and the cooling medium is a cooling oil.

9. An internal combustion engine comprising at least one cylinder in which a piston is arranged, the piston including: a piston body including a piston skirt and a piston head; the piston head including an at least partially circumferential cooling channel for receiving a cooling medium, the cooling channel open on a side facing away from a piston crown; at least one cooling channel cover at least partially closing the cooling channel; a piston pin boss having a boss bore configured to accommodate a piston pin; a piston pin lubricating channel fluidically connected to the cooling channel and extending in a direction of the piston pin; a pocket disposed on the piston body, the pocket at least partially defining the piston pin lubricating channel; and wherein the at least one cooling channel cover has at least one lug that is offset radially inward and, together with the pocket, defines the piston pin lubricating channel.

10. The internal combustion engine as claimed in claim 9, wherein the piston pin lubricating channel is aligned such that the cooling medium flowing therethrough impinges on at least one of the piston pin boss and the piston pin.

11. The internal combustion engine as claimed in claim 9, wherein the at least one cooling channel cover is structured as a two-part sheet-metal ring having at least one cooling medium inlet opening and at least one cooling medium outlet opening.

12. The internal combustion engine as claimed in claim 9, wherein: a second pocket is disposed on the piston body spaced apart by 180 in a circumferential direction from the pocket; and the at least one lug includes two lugs spaced apart by 180 in the circumferential direction and offset radially inward.

13. The internal combustion engine as claimed in claim 9, wherein the at least one cooling channel cover is clamped between an annular wall of the piston head and an annular rib of the piston head.

14. The internal combustion engine as claimed in claim 9, wherein the at least one cooling channel cover has at least one radial longitudinal section which is deep drawn on a side facing away from the piston crown.

15. The internal combustion engine as claimed in claim 14, wherein the at least one radial longitudinal section is disposed in a region of the at least one lug.

16. The internal combustion engine as claimed in claim 9, wherein the at least one cooling channel cover includes a drip edge on a radially inner longitudinal end, the drip edge projecting over at least one piston pin.

17. The internal combustion engine as claimed in claim 9, wherein the at least one cooling channel cover includes a drip edge on a radially inner longitudinal end of the at least one lug, the drip edge projecting over at least one piston pin.

18. The internal combustion engine as claimed in claim 9, wherein at least one of: the piston is one of a steel piston and a cast piston; and the cooling medium is a cooling oil.

19. The piston as claimed in claim 1, wherein the at least one cooling channel cover includes a drip edge on a radially inner longitudinal end of the at least one lug, the drip edge projecting over at least one piston pin.

20. The piston as claimed in claim 6, wherein the at least one radial longitudinal section is disposed in a region of the at least one lug.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, in which each of the figures is schematic:

(2) FIG. 1 shows a section through a piston according to the invention for an internal combustion engine in the region of a piston pin lubricating channel,

(3) FIG. 2 shows a plan view of a cooling channel cover, which is shaped as a two-part sheet-metal ring, on which is arranged a single lug.

DETAILED DESCRIPTION

(4) FIG. 1 shows a section through a piston 1 according to the invention for an internal combustion engine 2, otherwise not shown, as a detail view in the region of a piston pin lubricating channel 14. The piston 1 is designed as a substantially one-piece piston body 5, wherein the piston 1 may be referred to as a multi-part piston 1 by virtue of a subsequently fitted cooling channel cover 10, which is explained in greater detail below. The piston body 5 has a piston skirt 3 and a piston head 4, wherein an at least partially circumferential cooling channel 6 for receiving a cooling medium 7 is formed in the piston head 4. Radially toward the outside, the cooling channel 6 is bounded by an annular wall 21 and, radially toward the inside, is bounded by an annular rib 22. The cooling channel 6 is of open design on a side facing axially away from a piston crown 8. In the region of the piston crown 8, the piston 1 furthermore has a combustion chamber recess 9 with a central dome 25. Of course, the dome 25 can also be arranged noncentrally. Moreover, the piston 1 shown has two mutually spaced piston pin bosses 11, which each have a boss bore 12 to accommodate a piston pin, which is not otherwise shown. The piston pin can be clamped in the piston pin bosses 11 in a fixed manner or, preferably, can be mounted in a floating manner in the piston pin bosses 11. To cover the cooling channel 6, the cooling channel cover 10 already mentioned above, which at least partially closes the cooling channel 6, is provided. A pocket 15, which forms at least part of the piston pin lubricating channel 14, is arranged on the piston body 5 on a side facing away from the combustion chamber recess 9, in the region of the transition from the annular rib 22 to the piston crown 8. According to FIG. 1, the arrangement of the pocket 15 gives rise to the formation of a part of the piston pin lubricating channel 14 which is closed with respect to the piston crown 8 and on both sides in the circumferential direction 20. The piston pin lubricating channel 14 extends radially outward into the cooling channel 6 and radially inward at least in the direction of the piston crown or in the direction of the piston pin bosses 11. The cooling channel 6 and the piston pin lubricating channel 14 are thus connected fluidically to one another. To cover the piston pin lubricating channel 14 axially, the cooling channel cover 10 has, in the region of the pocket 15, a lug 16, which is offset radially inward and, together with the pocket 15, forms the piston pin lubricating channel 14 on the piston body 5.

(5) The piston pin lubricating channel 14 can preferably be configured in such a way that the cooling medium 7 flows via the cooling channel 6 through the piston pin lubricating channel 14 and then impinges directly on the piston pin boss 11 or the piston pin. Moreover, the piston 1 according to the invention can have two piston pin lubricating channels 14 which are offset by 180 in the circumferential direction 20 and which are each formed by two pockets 15 on the piston body 15 and two lugs 16 on the cooling channel cover 10.

(6) The cooling channel cover 10 can be clamped under a preload between the annular wall 21 and the annular rib 22. For this purpose, groove-shaped recesses, into which the cooling channel cover 10 extends and in which it can be supported, can be provided respectively on the annular wall 21 and/or on the annular rib 22. It is likewise conceivable for the cooling channel 10 to undergo a certain curvature under the preload. Furthermore, the cooling channel cover 10 can have a drip edge 23 on a radially inner longitudinal end, in particular on a radially inner longitudinal end of the lug 16. This drip edge 23 can project radially inward over at least one piston pin of this kind, as a result of which the cooling medium 7 dripping off the drip edge 23 impinges vertically on the piston pin.

(7) The piston 1 as such can expediently be designed as a steel piston or as a cast piston 1, e.g. composed of gray cast-iron or precision cast material. Moreover, the cooling medium 7 can be a cooling oil 24, which, on the one hand, has at least a certain thermal conductivity to allow cooling of the vacant locations and, on the other hand, has a certain lubricating capacity to ensure that wear on the mechanically moved components is reduced.

(8) FIG. 2 shows a plan view of a cooling channel cover 10 of this kind, which is shaped as a two-part sheet-metal ring 17 with a single lug 16 arranged thereon. Respective recesses 27, which are provided as a cooling medium inlet opening 18 and/or as a cooling medium outlet opening 19, can be arranged on the opposite sides of the sheet-metal ring sections 26 of the two-part sheet-metal ring 17, said sections being mirror-symmetrical with the exception of the lug 16. It is likewise conceivable for the cooling channel cover 10 to have two lugs 16, which are each arranged spaced apart by 180. The lug 16 projects radially inward and can be pressed out axially from the remainder of the sheet-metal ring 17 as such. For example, the lug 16 may be deep drawn at least over a radial longitudinal section of a side facing or facing away from the piston crown 8.