DE102012207951B4 - Pistons of an internal combustion engine - Google Patents

Abstract

Pistons of an internal combustion engine, with an upper piston part (10) and a lower piston part (11), with a piston pin (12), which is mounted in the lower piston part (11) and is used to connect the piston to a connecting rod (13) of the internal combustion engine, with a between the upper piston part (10) and the lower piston part (11) for cooling oil for cooling the piston, which is connected via at least one transfer bore (17) to an outer cooling chamber (15) formed between the upper piston part (10) and a lower piston part (11). 16) and with a cooling oil guide sleeve (19) which is used to guide cooling oil guided through a bore (18) in the connecting rod (13), characterized in that at least one bore (21) is made in the lower piston part (11). is, which cooperates with the cooling oil guide sleeve (19) in such a way that through the connecting rod (13) and the cooling oil guide sleeve (19) guided cooling oil directly to the outer cooling chamber (16) can be fed, wherein in the At least one bore (22) is introduced into the cooling oil guide sleeve (19), which interacts with one of the bores (21) of the lower piston part (11) and the lower piston part (11) has a radially circumferential groove (25) radially on the inside adjacent to the cooling oil guide sleeve (19). into which the or each bore (21) of the lower piston part (11) opens and which cooperates with the or each bore (22) of the cooling oil guide sleeve (19).

Description

The invention relates to a piston of an internal combustion engine according to the preamble of claim 1 or according to the preamble of independent claim 2.

From the DE 35 18 721 C2 a piston of an internal combustion engine is known, which comprises a piston upper part and a piston lower part, which are preferably screwed together. A piston pin is mounted in the lower piston part, the piston pin serving to connect the piston to a connecting rod of the internal combustion engine. The piston according to DE 35 18 721 C2 is oil-cooled, with an inner cooling chamber for cooling oil on the one hand and an outer cooling chamber for cooling oil on the other hand being formed between the upper piston part and the lower piston part, and the inner cooling chamber being connected to the outer cooling chamber via at least one transfer bore. In order to introduce cooling oil into the inner cooling chamber, according to this prior art, a feed bore for cooling oil is integrated into the connecting rod, with the cooling oil being transferrable from the connecting rod into the inner cooling chamber using a two-piece cooling oil guide sleeve. A first, neck-like part of the two-piece cooling oil guide sleeve is after DE 35 18 721 C2 fixed immovably in the lower part of the piston. A funnel-like, movable part of the cooling-oil guiding sleeve interacts with this stationary, neck-like part of the two-part cooling-oil guiding sleeve in such a way that a spring element, which engages between the two parts of the two-part cooling-oil guiding sleeve, resiliently presses the funnel-like part of the same into sliding contact against a connecting rod head of the connecting rod. The use of such multi-part cooling oil guide sleeves for transferring the cooling oil from the bore in the connecting rod into the inner cooling space is disadvantageous, since the assembly of such multi-part cooling oil guide sleeves is only possible with great effort. It is therefore already known from practice to replace such multi-part cooling oil guide sleeves with one-piece cooling oil guide sleeves.

From the DE 37 02 694 C1 is a piston with a piston upper part and a piston lower part, with a piston pin, which is mounted in the piston lower part and is used to connect the piston to a connecting rod of the internal combustion engine. The piston is equipped with an inner cooling chamber for cooling oil, which is formed between the upper piston part and the lower piston part, which is connected via at least one transfer bore to an outer cooling chamber formed between the upper piston part and a lower piston part, and with a cooling oil guide sleeve, which is used to guide through a bore in the connecting rod guided cooling oil is used

Furthermore, already in the DE 27 51 306 A1 , the DE 35 18 721 A1 , the DE 873 185 B or the DE 15 25 228 A oil-cooled, multi-part trunk pistons of an internal combustion engine are described.

Proceeding from this, the object of the present invention is to create a new type of piston for an internal combustion engine. This object is solved by a piston according to claim 1 or 2.

According to the invention, at least one bore is introduced into the lower piston part, which interacts with the cooling oil guide sleeve in such a way that cooling oil guided through the connecting rod and the cooling oil guide sleeve can be fed directly to the outer cooling chamber. For this purpose, at least one bore is introduced into the cooling oil guide sleeve, which interacts with one of the bores of the lower piston part.

With the present invention, it is proposed for the first time to supply cooling oil, which is guided via the connecting rod and the cooling oil guide sleeve, for cooling the piston at least partially directly to the outer cooling chamber, bypassing the inner cooling chamber. This enables effective cooling of the piston in areas of the piston that are subjected to high thermal loads.

According to the invention, the lower piston part of the piston has a radially circumferential groove radially inwardly adjacent to the cooling oil guide sleeve, into which the or each bore of the lower piston part opens and which interacts with the or each bore of the cooling oil guide sleeve. Alternatively, the cooling oil guide sleeve of the piston has a radially circumferential groove on the radial outside, into which the or each bore of the cooling oil guide sleeve opens and which interacts with the or each bore of the lower piston part.

With these two alternatives it can be ensured that when the cooling oil guide sleeve of the piston is rotatably mounted in the piston lower part, a safe transport of the cooling oil is always guaranteed starting from the connecting rod via the cooling oil guide sleeve directly in the direction of the outer cooling chamber.

According to an advantageous development of the invention, a first subset of the cooling oil guided through the connecting rod can be fed directly to the outer cooling space via the cooling oil guide sleeve, with a second subset of the cooling oil guided through the connecting rod being able to be fed directly to the inner cooling space via the cooling oil guide sleeve. For this purpose, a further bore is introduced into the cooling oil guide sleeve, via which the second subset of the cooling oil can be fed to the inner cooling space. According to this advantageous development, a first portion of the cooling oil is fed directly to the outer cooling space and a second portion of the cooling oil is fed directly to the inner cooling space. This can further improve the effectiveness of the cooling of the piston in areas of the piston that are subjected to high thermal loads.

• 1: einen Querschnitt durch einen erfindungsgemäßen Kolben in einer ersten Schnittrichtung;
• 2: einen Querschnitt durch den erfindungsgemäßen Kolben der 1 in einer zweiten Schnittrichtung;
• 3: einen Querschnitt durch den erfindungsgemäßen Kolben der 1 in einer dritten Schnittrichtung;
• 4: ein Detail des Kolbens der 1 bis 3 im Bereich einer Kühlölführhülse;
• 5: ein alternatives Detail im Bereich einer alternativen Kühlölführhülse;
• 6: ein weiteres alternatives Detail im Bereich einer weiteren alternativen Kühlölführhülse;
• 7: ein weiteres alternatives Detail im Bereich einer weiteren alternativen Kühlölführhülse;
• 8: ein weiteres alternatives Detail im Bereich einer weiteren alternativen Kühlölführhülse;
• 9: ein weiteres alternatives Detail im Bereich einer weiteren alternativen Kühlölführhülse; und
• 10: das Detail X der 9.

Preferred developments of the invention result from the dependent claims and the following description. Exemplary embodiments of the invention are explained in more detail with reference to the drawing, without being limited thereto. It shows:

• 1 : a cross section through a piston according to the invention in a first cutting direction;
• 2 : a cross section through the piston according to the invention 1 in a second cutting direction;
• 3 : a cross section through the piston according to the invention 1 in a third cutting direction;
• 4 : a detail of the piston of the 1 until 3 in the area of a cooling oil guide sleeve;
• 5 : an alternative detail in the area of an alternative cooling oil guide sleeve;
• 6 : another alternative detail in the area of another alternative cooling oil guide sleeve;
• 7 : another alternative detail in the area of another alternative cooling oil guide sleeve;
• 8th : another alternative detail in the area of another alternative cooling oil guide sleeve;
• 9 : another alternative detail in the area of another alternative cooling oil guide sleeve; and
• 10 : the detail X of 9 .

The present invention relates to an oil-cooled piston of an internal combustion engine, in particular an internal combustion engine designed as a diesel engine or gas engine or diesel-gas engine, such as a marine diesel engine. Such a piston is also referred to as a plunger.

1 until 3 each show cross sections through a piston according to the invention of an internal combustion engine in different cutting directions, the piston comprising an upper piston part 10 and a lower piston part 11 . The upper piston part 10 and the lower piston part 11 are preferably made of a light metal, steel or nodular cast iron. The upper piston part 10 and the lower piston part 11 are supported on one another and are preferably fastened to one another via fastening means designed as expansion screws.

A piston pin 12 is mounted in a bore of the lower piston part 11, the piston pin 12 serving to connect the piston to a connecting rod 13 of the internal combustion engine. From the connecting rod 13 is in 2 a so-called connecting rod head 14 is shown.

Between the upper piston part 10 and the lower piston part 11 there is an inner cooling chamber 15 on the one hand and an outer cooling chamber 16 for cooling oil on the other hand, the inner cooling chamber 15 being connected to the outer cooling chamber 16 according to FIG 2 is connected via transfer holes 17.

Cooling oil, which is used to cool the piston, can be fed to the piston via a bore 18 which extends through the connecting rod 13 and the connecting rod head 14 . With the connecting rod 13 and the connecting rod head 14 of the connecting rod 13, a cooling oil guide sleeve 19 acts together, which in the embodiment of 1 until 3 is movably mounted in the lower piston part 11 and a spring element 20 in the embodiment of 1 until 3 is pressed permanently sealingly against the connecting rod head 14 of the connecting rod 13.

4 shows an enlarged detail from the piston of the 1 until 3 in the area of the cooling oil guide sleeve 19, which, as already stated, is permanently pressed against the connecting rod head 14 by the spring element 20. The cooling oil guide sleeve 19 is designed as a one-piece cooling oil guide sleeve. The spring element 20, which presses the cooling oil guide sleeve 19 permanently against the connecting rod head 14 of the connecting rod 13, is supported on the one hand on the cooling oil guide sleeve 19 and on the other hand on the lower piston part 11.

For the purposes of the present invention, at least one bore 21 is introduced into the lower piston part 11, which interacts with the cooling oil guide sleeve 19 in such a way that cooling oil supplied to the piston via the connecting rod 13 can be fed directly to the outer cooling chamber 16, starting from the connecting rod 13 and the cooling oil guide sleeve 19 is. For this purpose, at least one bore 22 is made in the cooling oil guide sleeve 19 and interacts with one of the bores 21 in the lower piston part 11 .

The or each bore 21 of the lower piston part 11 and the or each bore 22 of the cooling oil guide sleeve 19, which each serve to guide the cooling oil starting from the connecting rod 13 directly in the direction of the outer cooling chamber 16, bypassing the inner cooling chamber 15 relative to the connecting rod 13 in the axial direction and radial direction obliquely in the direction of the outer cooling chamber, the same therefore run according to the representations of 1 until 4 obliquely upwards.

In the embodiment of 1 until 4 is all cooling oil, which is supplied via the piston rod 13 to the piston for cooling the same, first directly to the outer cooling chamber 16 and then via the transfer bores 17 to the inner cooling chamber 15 can be supplied, with the cooling oil according to 3 can be discharged via at least one bore 23 in the lower piston part 11 from the inner cooling chamber 15 and thus from the piston. According to 3 the bores 23 for discharging the cooling oil are introduced into the lower piston part 11 in such a way that they are positioned radially on the outside around the cooling oil guide sleeve 19 .

In 1 until 3 is visualized for the embodiment shown there, the leadership of the cooling oil by unspecified arrows, where 1 until 3 it can be seen that cooling oil, which is supplied to the piston via the connecting rod 13, proceeds from the connecting rod 13 into the cooling oil guide sleeve 19, proceeds from the cooling oil guide sleeve 19 via the bores 21 and 22 to the outer cooling chamber 16, starting from the outer cooling chamber 16 reaches the inner cooling chamber 15 via the transfer bores 17, and can be derived from the piston via the bores 23 starting from the inner cooling chamber 15.

As already stated, the cooling oil guide sleeve 19 is in the embodiment 1 until 4 movable, namely at least axially displaceable, guided in the piston lower part 11.

When the cooling oil guide sleeve 19 is additionally guided in a rotatable manner in the lower piston part 11, it is preferable, as in 5 shown, a radially circumferential groove 24 is introduced radially on the outside into the cooling oil guide sleeve 19, into which the bores 22 of the cooling oil guide sleeve 19 all open and which interact with the bores 21 of the lower piston part 11, namely in such a way that in every relative rotational position of the cooling oil guide sleeve 19 to the lower piston part 11 a transport of the cooling oil starting from the cooling oil guide sleeve 19 in the direction of the outer cooling chamber 16 is guaranteed.

As 6 can be removed, such a circumferential groove 25 can alternatively also be made radially on the inside in the lower piston part 11 adjacent to the cooling oil guide sleeve 19, in which case all bores 21 in the lower piston part 11 open into this radially circumferential groove 25 in the lower piston part 11 and this groove 25 with the Bores 22 of the cooling oil guide sleeve 19 acts together.

Another variant is shown 8th , where the variant of the 8th from the variant of 1 until 4 differs only by the specific design of the cooling oil guide sleeve 19, namely by the contour of an interior space of the cooling oil guide sleeve 19 that serves to guide cooling oil 8th compared to that 1 an inner space of the cooling oil guide sleeve 19 serving to guide the cooling oil via a smaller volume as well as curved guide surfaces 28 which serve to guide the cooling oil starting from the bore 18 of the connecting rod 13 in the direction of the bores 22 of the cooling oil guide sleeve 19.

7 illustrates another variant of the invention, wherein in the variant of 7 Cooling oil, which is fed to the piston via the bore 18 in the connecting rod 13 and in the connecting rod head 14 of the same, can not only be fed directly to the outer cooling chamber 16, but also to the inner cooling chamber 15, namely via a further bore made in the cooling oil guide sleeve 19 26 which extends in the axial direction of the connecting rod 13.

In the variant of 7 Accordingly, a first portion of the cooling oil fed through the connecting rod 13 can be fed directly to the outer cooling chamber 16 via the cooling oil guide sleeve 19 and the lower piston part 11, namely via the bores 21 and 22, a second portion of the cooling oil fed through the connecting rod 13 via the cooling oil guide sleeve 19, namely via the bore 26 directly to the inner cooling chamber 15 can be fed.

The exemplary embodiments 1 until 8th What they all have in common is that the cooling oil guide sleeve 19 is movably guided in the lower piston part 11 and is permanently pressed against the connecting rod head 14 of the connecting rod 13 in a sealing manner via a spring element 20 .

Contrast show 9 and 10 a variant of the invention in which the cooling oil guide sleeve 19 is immovably accommodated in the lower piston part 11, namely via a press fit between the cooling oil guide sleeve 19 and the piston lower part 11. In this case, between the immovable cooling oil guide sleeve 19 and the connecting rod head 14 of the connecting rod 13 according to detail X 9 and 10 permanently formed a gap 27, wherein the gap 27 can have a gap dimension d in the order of between 0.1 mm and 5 mm.

Although in 1 until 10 not shown, the cooling oil guide sleeve 19 can be an integral part of the lower piston part 11 . In this case, the in 9 and 10 Cooling oil guide sleeve 19 designed as a separate cooling oil guide sleeve 19, which cannot be moved or is stationary in the lower piston part 11 is held via a press fit, omitted and the contour of the cooling oil guide sleeve 19 is introduced directly into the lower piston part 11.

Reference List

10

piston top

11

buttstock

12

gudgeon pin

13

connecting rod

14

connecting rod head

15

fridge

16

fridge

17

transfer hole

18

drilling

19

cooling oil guide sleeve

20

spring element

21

drilling

22

drilling

23

drilling

24

groove

25

groove

26

drilling

27

gap

28

guide surface

Claims (10)

Pistons of an internal combustion engine, with a piston upper part (10) and a piston lower part (11), with a piston pin (12) which is mounted in the piston lower part (11) and serves to connect the piston to a connecting rod (13) of the internal combustion engine, with a between the upper piston part (10) and the lower piston part (11) for cooling oil for cooling the piston, which is connected via at least one transfer bore (17) to an outer cooling chamber (15) formed between the upper piston part (10) and a lower piston part (11). 16) and with a cooling oil guide sleeve (19) which serves to guide cooling oil guided through a bore (18) in the connecting rod (13), characterized in that at least one bore (21) is made in the lower piston part (11). is, which cooperates with the cooling oil guide sleeve (19) in such a way that through the connecting rod (13) and the cooling oil guide sleeve (19) guided cooling oil can be fed directly to the outer cooling chamber (16), wherein in di e Cooling oil guide sleeve (19) at least one bore (22) is introduced, which interacts with one of the bores (21) of the piston lower part (11) and the piston lower part (11) radially on the inside adjacent to the cooling oil guide sleeve (19) has a radially circumferential groove (25) has, into which the or each bore (21) of the lower piston part (11) opens and which cooperates with the or each bore (22) of the cooling oil guide sleeve (19). Pistons of an internal combustion engine, with a piston upper part (10) and a piston lower part (11), with a piston pin (12) which is mounted in the piston lower part (11) and serves to connect the piston to a connecting rod (13) of the internal combustion engine, with a between the upper piston part (10) and the lower piston part (11) for cooling oil for cooling the piston, which is connected via at least one transfer bore (17) to an outer cooling chamber (15) formed between the upper piston part (10) and a lower piston part (11). 16) and with a cooling oil guide sleeve (19) which serves to guide cooling oil guided through a bore (18) in the connecting rod (13), characterized in that at least one bore (21) is made in the lower piston part (11). is, which cooperates with the cooling oil guide sleeve (19) in such a way that through the connecting rod (13) and the cooling oil guide sleeve (19) guided cooling oil can be fed directly to the outer cooling chamber (16), wherein in di e Cooling oil guide sleeve (19) at least one bore (22) is introduced, which interacts with one of the bores (21) of the lower piston part (11) and the cooling oil guide sleeve (19) has a radially circumferential groove (24) radially on the outside, into which the or each bore (22) of the cooling oil guide sleeve (19) opens out and which interacts with the or each bore (21) of the lower piston part (11). piston after claim 2 , characterized in that the or each bore (22) of the cooling oil guide sleeve (19) and the or each bore (21) of the lower piston part (11), each of which guides the cooling oil starting from the connecting rod (13) in the direction of the outer Serve cooling space (16) bypassing the inner cooling space (15), based on the connecting rod (13) in the axial direction and radial direction obliquely towards the outer cooling space (16). Piston after one of Claims 1 until 3 , characterized in that a first portion of the cooling oil guided through the connecting rod (13) can be fed directly to the outer cooling chamber (16) via the cooling oil guide sleeve (19) and the lower piston part (11), and that a second portion of the cooling oil fed through the connecting rod (13 ) guided cooling oil via the cooling oil guide sleeve (19) directly to the inner cooling chamber (15) can be fed. piston after claim 4 , characterized in that in the cooling oil guide sleeve (19) a Boh tion (26) is introduced, via which the second subset of the cooling oil can be fed to the inner cooling chamber (15). piston after claim 5 , characterized in that the respective bore (26) of the cooling oil guide sleeve (19) relative to the connecting rod (13) extends in the axial direction. Piston after one of Claims 1 until 6 , characterized in that the cooling oil guide sleeve (19) in the piston lower part (11) movably guided and via a spring element (20) against a connecting rod head (14) of the connecting rod (13) is pressed permanently sealing. Piston after one of Claims 1 until 6 , characterized in that the cooling oil guide sleeve (19) is accommodated in the lower piston part (11) in such a way that a gap (27) is formed between the cooling oil guide sleeve (19) and the connecting rod head (14) of the connecting rod (13). piston after claim 8 , characterized in that the cooling oil guide sleeve (19) is immovably pressed into the lower piston part (11). Piston after one of Claims 1 until 6 , characterized in that the cooling oil guide sleeve (19) is an integral part of the lower piston part (11).

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