Piston

Abstract

A piston for an internal combustion engine may include a cooling duct having at least one feed opening. The piston may also include a feed funnel arranged within the at least one feed opening. The feed funnel may be fixed in the at least one feed opening via a blind rivet connection.

Claims

1. A piston for an internal combustion engine, comprising: a cooling duct having at least one feed opening; a feed funnel arranged within the at least one feed opening; and wherein the feed funnel is fixed in the at least one feed opening via a blind rivet connection.

2. The piston according to claim 1, wherein at least one of: the at least one feed opening is configured as a bore; and the cooling duct is closed via a cooling duct covering, and the at least one feed opening is configured as a through opening in the cooling duct covering.

3. The piston according to claim 1, wherein: the cooling duct is closed via a two-piece cooling duct covering having a first cooling duct covering part and a second cooling duct covering part; and the at least one feed opening is disposed at a joint between the first cooling duct covering part and the second cooling duct covering part.

4. The piston according to claim 1, wherein: the blind rivet connection is configured as a blind rivet nut connection; and the feed funnel includes: an annular collar; a funnel; an internal thread disposed at an end of the feed funnel that faces away from the funnel; and a first upset region disposed between the internal thread and the annular collar.

5. The piston according to claim 1, wherein: the blind rivet connection is configured as a blind rivet nut connection; and the feed funnel includes: a funnel; an internal thread disposed at an end of the feed funnel that faces away from the funnel; and a first upset region and a second upset region disposed between the funnel and the internal thread.

6. The piston according to claim 1, wherein the feed funnel has at least one of: an axial length of 10 mm to 35 mm; and a funnel length of 6 mm to 16 mm.

7. The piston according to claim 1, wherein the feed funnel has at least one of: a maximum diameter of 10 mm to 14 mm; and a standpipe internal diameter of approximately 2 mm to 8 mm.

8. A feed funnel of a piston, wherein the feed funnel is configured as at least one of a blind rivet and a blind rivet nut.

9. The feed funnel according to claim 8, comprising: a funnel; an internal thread disposed at an end facing away from the funnel; a first upset region disposed between the internal thread and the funnel; at least one of (i) an annular collar and (ii) a second upset region disposed between the funnel and the first upset region; and wherein the at least one of the blind rivet and the blind rivet nut includes the blind rivet nut.

10. The feed funnel according to claim 9, wherein the feed funnel has at least one of: an axial length of 10 mm to 35 mm; and a funnel length of 6 mm to 16 mm.

11. The feed funnel according to claim 9, wherein the feed funnel has at least one of: a maximum diameter of 10 mm to 14 mm; and a standpipe internal diameter of approximately 2 mm to 8 mm.

12. A method for mounting a feed funnel in a piston comprising: plugging an end of the feed funnel, which faces away from a funnel of the feed funnel, into a feed opening of a cooling duct of the piston; and fixing the feed funnel in the feed opening via a blind rivet connection.

13. The method according to claim 12, wherein the blind rivet connection is a blind rivet nut connection.

14. The piston according to claim 1, wherein the feed funnel includes: an elongated annular body including a first upset region bulging radially outward therefrom; a funnel disposed at a first axial end of the annular body; and an internal thread disposed within the annular body at a second axial end of the annular body.

15. The piston according to claim 14, wherein: the feed funnel has an axial length of 10 mm to 35 mm; the funnel has a funnel axial length of 6 mm to 16 mm; the annular body has an internal diameter of 2 mm to 8 mm; and an end of the funnel disposed opposite the annular body has a diameter of 10 mm to 14 mm.

16. The piston according to claim 14, wherein the feed funnel further includes an annular collar projecting radially outward from the annular body.

17. The piston according to claim 16, further comprising a cooling duct covering closing the cooling duct, wherein: the at least one feed opening is configured as a through opening in the cooling duct covering; and the cooling duct covering is secured axially between the first upset region and the annular collar such that the blind rivet connection is defined by the first upset region and the annular collar.

18. The piston according to claim 14, wherein the annular body further includes a second upset region bulging radially outward therefrom.

19. The piston according to claim 18, further comprising a cooling duct covering closing the cooling duct, wherein: the at least one feed opening is configured as a through opening in the cooling duct covering; and the cooling duct covering is secured axially between the first upset region and the second upset region such that the blind rivet connection is defined by the first upset region and the second upset region.

20. The piston according to claim 5, wherein the first upset region and the second upset region of the feed funnel bulge radially outward therefrom.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings, in each case diagrammatically:

(2) FIG. 1a shows a sectional illustration through a piston according to the invention with a feed funnel according to the invention in accordance with a first embodiment, in a way which is not yet fixed in a feed opening,

(3) FIG. 1b shows an illustration as in FIG. 1a, but after fixing,

(4) FIG. 2a shows an illustration as in FIG. 1a, but with a feed funnel with two upset regions,

(5) FIG. 2b shows an illustration as in FIG. 2a, but in the case of a feed funnel which is fixed in the feed opening.

DETAILED DESCRIPTION

(6) In accordance with FIGS. 1 and 2, a piston 1 according to the invention for an internal combustion engine 2 (not shown in greater detail) has a cooling duct 3 which has at least one feed opening 4 with a feed funnel 5 which is arranged therein. According to the invention, said feed funnel 5 is then fixed in the feed opening 4 by means of a blind rivet connection 6 (cf. FIGS. 1 and 2). This affords the great advantage that simple mounting and fixing of the feed funnel 5 in the feed opening 4 is possible from only a single side, for example an underside of the piston. In addition, further, in particular complex, fixing operations are dispensed with, such as riveting, welding or brazing of the feed funnel 5.

(7) Here, the feed opening 4 can be configured as a bore in the piston 1, or else the cooling duct 3 is closed from below by means of a cooling duct covering 8, the feed opening 4 being configured as a through opening 7 in the cooling duct covering 8. Here, according to FIGS. 1 and 2, in each case merely one feed opening 4 is shown in a cooling duct covering 8; it goes without saying that the other embodiment is readily comprehensible to a person skilled in the art. The cooling duct 3 can be closed, for example, by way of a two-piece cooling duct covering 8′ with a first cooling duct covering part 9a and a second cooling duct covering part 9b, it then being possible for the feed opening 4 to be provided at a joint 10 of the two cooling duct covering parts 9a, 9b, which simplifies the production of the feed opening 4 considerably, since merely a semicircle has to also be punched out in the two cooling duct covering parts 9a, 9b, which semicircles form the through opening 7 or the feed opening 4 in the assembled state.

(8) If the feed funnel 5 is looked at more closely, it can be seen that, in the present case according to FIGS. 1a and 1b, it has an annular collar 11 which serves as a stop in the case of the feed funnel 5 being pushed into the feed opening 4. A feed funnel 5 of this type likewise has an internal thread 13 at an end which faces away from a funnel 12, a first upset region 14 being arranged between the internal thread 13 and the annular collar 11, which first upset region 14 is upset and in the process bulged to the outside in the case of the production of the blind rivet connection 6. The reshaped upset region 14 and the annular collar 11 therefore clamp the cooling duct covering 8 between them after the blind rivet connection 6 is produced, and reliably fix the feed funnel 5 in the feed opening 4 as a result.

(9) Here, mounting of the feed funnel 5 in the piston 1 or in the feed opening 4 takes place as follows:

(10) First of all, the feed funnel 5 is pushed with its funnel 12 over a threaded mandrel 15 of a blind rivet setting tool 16, and subsequently the internal thread 13 of the feed funnel 5 is screwed to an external thread 17 of complementary configuration with respect to it of the threaded mandrel 15. Subsequently, the threaded mandrel 15 is pushed together with the feed funnel 5 through the feed opening 4 until the feed funnel 5 bears with its annular collar 11 against an underside of the cooling duct covering 8, 8′ or against a lower edge of the feed opening 4. Subsequently, axial withdrawal of the threaded mandrel 15 takes place, as a result of which the latter pulls the internal thread 13 downwards and in the process deforms the first upset region 14 plastically to the outside, as shown according to FIG. 1b. It goes without saying that the axial withdrawal can purely theoretically also be achieved by way of a corresponding rotational movement of the threaded mandrel 15 in the internal thread 13; it goes without saying that the feed funnel 5 is fixed in the axial direction either, for example, on the annular collar 11 or on its funnel 12 and, as a result, counteracts the axial movement of the internal thread 13 downwards, which axial movement brings about the upset deformation of the first upset region 14. If the blind rivet connection 6 is then produced, the threaded mandrel 15 is rotated in the opposite direction and, as a result, is screwed with its external thread 17 out of the internal thread 13 of the feed funnel 5. Subsequently, the threaded mandrel 15 can be removed. As a result, the feed funnel 5 is fixed reliably in the feed opening 4 of the piston 1. In this case, the blind rivet connection 6 is configured as what is known as a blind rivet nut connection 6′.

(11) If the feed funnel 5 according to FIGS. 2a and 2b is considered, it can be seen that it likewise has an internal thread 13 at its longitudinal end which faces away from the funnel 12, a first upset region 14 and, in addition here, also a second upset region 18 once again lying between the funnel 12 and the internal thread 13. In this case, the fixing of the feed funnel 5 in the feed opening 4 can also be produced by means of a blind rivet nut connection 6′. To this end, a threaded mandrel 15 (not shown) is likewise pushed from below into the feed funnel 5 until it can be screwed with its external thread 17 into the internal thread 13 of the feed funnel 5. Subsequently, axial withdrawal of the upper part of the feed funnel 5 takes place, in which upper part the internal thread 13 lies, and at the same time supporting of the lower part of the feed funnel 5 takes place, for example on the funnel 12. As a result of the shortening of the axial length, the two upset regions 14, 18 are bulged and, as a result, the cooling duct covering 8, 8′ is clamped in between the two bulged upset regions 14, 18 (cf. FIG. 2b). It goes without saying that it can be provided here that the two upset regions 14, 18 have different stiffnesses, for example as a result of correspondingly predefined material weakening, as a result of which upsetting or bulging of the two upset regions 14, 18 after one another can be achieved.

(12) It goes without saying that purely theoretically fixing of the feed funnel 5 via a blind rivet connection 6 is also known, in the case of which the feed funnel 5 still has a rivet mandrel (not illustrated), and is held via the latter on the blind rivet setting tool 16 in a similar manner to a blind rivet. Via this, the feed funnel 5 is plugged into the feed opening 4 until, for example, it bears against an outer edge of the feed opening 4 with its stop, that is to say its annular collar 11. Subsequently, the rivet mandrel (not illustrated) is withdrawn by means of the blind rivet setting tool 16, as a result of which the first upset region 14 is upset and is bulged to the outside and, as a result, the cooling duct covering 8, 8′ is clamped in between it and the annular collar 11. In the case of further pulling, the rivet mandrel breaks at a predetermined break point, it then subsequently being necessary, that is to say after the removal of the rivet mandrel, for a through opening through the feed funnel 5 to still be produced, for example to be drilled.

(13) In general, the feed funnel 5 can have an axial length L of between 10 and 35 mm. A funnel length L.sub.T preferably lies between 6 mm and 16 mm (6 mm≤L.sub.T≤16 mm). A maximum diameter D.sub.max of the feed funnel lies between 10 and 14 mm, whereas a standpipe internal diameter D.sub.SL is approximately 2-8 mm. As a result of the stated length and diameter specifications, a predefined penetration of cooling oil into the cooling duct 3 can firstly be achieved, and also a predefined cooling oil quantity.

(14) It goes without saying that the invention is intended to protect not only the piston 1 with a feed funnel 5 which is arranged in it according to the invention via a blind rivet connection 6 or a blind rivet nut connection 6′, but rather also a feed funnel 5 of this type and the above-described mounting method for fixing it in the feed opening 4.

(15) It is possible by way of the feed funnel 5 according to the invention and the piston 1 according to the invention to achieve a positively locking connection between the feed funnel 5 and the feed opening 4, which positively locking connection makes both simple mounting from merely a single side, namely the underside of the piston, possible, and also reliable fixing of the feed funnel 5 in the feed opening 4. Via this, feed funnels 5 of this type can be produced inexpensively and have a long service life on account of their usually metallic configuration. Here, fixing or setting of the feed funnel 5 in the feed opening 4 can be brought about without problems even by inexperienced workers.