WO2012116987A1

WO2012116987A1 - Cooled piston and method for producing it

Info

Publication number: WO2012116987A1
Application number: PCT/EP2012/053363
Authority: WO
Inventors: Matthias Laqua
Original assignee: Ks Kolbenschmidt Gmbh
Priority date: 2011-03-01
Filing date: 2012-02-28
Publication date: 2012-09-07
Also published as: EP2681436A1; DE102011012758A1; CN103380283A; KR20140007381A; JP2014508887A; JP6005071B2

Abstract

The invention relates to a piston (1) of an internal combustion engine, having a piston head (14) and a cooling duct (9), into which a dividing element (10) with at least one opening (13) is positioned, as a result of which a pressure chamber (11) is produced between a part of the wall of the cooling duct (9) and the separating element (10), which pressure chamber (11) is filled with pressurized oil by means of at least one oil feed line (15), wherein the oil exits from the opening (13) and impinges at least on a region of the cooling duct (9'), with the result that the piston can be cooled. According to the invention, it is provided that the non-machined separating element (10) is positioned on the wall of the later cooling duct (9), with the result that the separating element (10) can also be machined during the production of the piston (1), wherein, as a result, the machining operation of the separating element (10) which is separate from the machining operation of the piston (1) is dispensed with. Furthermore, the invention relates to a method for producing a piston (1) of this type for an internal combustion engine.

Description

DESCRIPTION

Cooled flask and process for its production

The invention relates to a piston of an internal combustion engine, comprising a piston head and a cooling channel, in which a separating element is positioned with at least one opening, whereby a pressure space between a part of the wall of the cooling channel and the separating element is formed with the oil under pressure by means of at least one oil inlet is filled, wherein the oil exits the opening and impinges at least on a portion of the cooling channel, so that the piston is cooled, and a method for producing a piston of an internal combustion engine, which is cooled after production of the piston by sprayed oil, said Oil from a pressure chamber through at least one opening of a separating element, which is positioned in a cooling channel of the piston and thereby forms in the cooling channel with oil via at least one oil inlet fillable pressure space between a part of the wall of the cooling channel and the separating element, at least targeted to a range of the cooling duct is injected as by pressure generated in the oil-filled pressure chamber.

From WO 2007/1 10056 A1 a two-part piston is known, in the cooling channel of which an annular partition wall arranged parallel to the piston bottom is provided, which has one or more nozzle-like openings which are arranged such that their respective exit jet aligns with the underside of the piston crown is. In this case, the space located below the partition is preferably completely filled with cooling oil, so that at the at least one nozzle-like opening a particularly high cooling pressure is applied and the cooling oil jet with ejection from the opening undergoes optimal acceleration. According to WO 2007/1 10056 A1, the dividing wall is between the inner or outer support surface of the two-part piston and the support surface associated therewith arranged so that it is particularly easy to assemble and fasten. Alternatively, it is possible according to WO 2007/1 10056 A1 that the dividing wall is designed as a wall part integrated in the piston head or in the piston shaft, which is also molded during the production of the piston. In a further alternative embodiment according to WO 2007/1 10056 A1, the dividing wall is arranged in the region of the cooling channel formed by the piston skirt.

A disadvantage of this piston known from the prior art is that the partition for the piston is manufactured as a separate component and is therefore manufactured independently of the piston production. A partition wall which has already been cast into the piston also has the disadvantage that the dividing wall and the cooling channel of the piston can only be processed to a limited extent after the casting process.

The object of the invention is therefore to provide a good coolable piston, which is simple and inexpensive to produce and which does not have the above-mentioned disadvantages of the prior art.

The object is achieved in that the unprocessed separating element can be positioned on the wall of the later cooling channel, so that the separating element can be machined in the production of the piston, thereby eliminating the processing of the piston separate processing of the separating element.

It is advantageous that the separating element can be positioned in the unprocessed state on the wall of the subsequent cooling channel of the piston, so that a separate production of the piston production of the separating element is eliminated, since the separating element is processed in the production of the piston. As a result, the separator, as well as the piston, simple and inexpensive to produce. Furthermore, by positioning the unprocessed separating element on the wall of the later cooling channel of the piston, an automatic machining of the piston together with the separating element is possible, thereby reducing production costs and, in addition, reducing the production time. Furthermore, it is advantageous that by the inventive partition the reliability of the piston is increased, since the piston is well cooled by means of the separating element.

In an advantageous embodiment, the piston consists of an upper part and a lower part. It is possible to manufacture the upper part and the lower part separately, for example by means of a primary shaping production method, for example by means of casting, by means of a forming manufacturing method, for example by forging, and / or by means of a metal-cutting manufacturing method, for example by means of turning, milling and / or grinding.

The upper part and the lower part of the piston consist in a further advantageous embodiment of a same light metal material, such as aluminum, magnesium or their alloys, or of a same metallic material, such as a steel material or a material for casting. Alternatively, it is possible that the upper part and the lower part each consist of a different one of the aforementioned materials.

The upper part adjoins the lower part in the assembled state in a further advantageous embodiment, at least on a common, corresponding bearing surface of the upper part and the lower part, so that the upper part and the lower part are easily positionable.

The upper part is connected in a further advantageous embodiment with the lower part in the assembled state of the piston, for example by means of at least one screw connection, welded connection, press connection, clamp connection or the like.

In a further advantageous embodiment, the unprocessed separating element is attached to the upper part, so that the separating element in the context of the processing of the upper part is editable. Alternatively, it is possible that the unprocessed separating element is attached to the lower part, so that the separating element in the context of the processing of the lower part is machined. It is possible that the unprocessed separating element on the upper part or the lower part by means of at least a screw connection, welded joint, press connection, clamp connection or the like is attached.

In a further advantageous embodiment, the unprocessed separating element is annular. It is possible that the unprocessed separating element is composed of several individual pieces, for example, the composite result in a circumferential ring shape. Alternatively, it is possible that the piston has a plurality of unprocessed separating elements as individual parts, which are each inserted into a cooling channel formed interrupted. In a particularly preferred embodiment, the unprocessed separating element is formed as a one-piece ring, so that the one-piece ring can be positioned in a circumferential cooling channel. The unprocessed separating element may for example consist of a light metal material, such as aluminum, magnesium or their alloys, or of a metallic material, such as a steel material or a material for casting.

In a further preferred embodiment, the opening of the separating element is formed nozzle-shaped after processing of the separating element. It is possible that the unprocessed separating element already has partially prefabricated openings, which are machined nozzle-shaped in the context of processing. Alternatively, it is possible that the unprocessed separating element has no openings, so that the openings are incorporated only in the context of processing in the separating element.

By means of the nozzle-shaped openings, it is possible for the oil emerging from the opening of the separating element to be targeted to at least one region of the wall of the cooling channel, in particular to at least one region on the underside of the piston crown and / or to at least one region of the wall opposite the ring section, is alignable. The nozzle-shaped opening of the separating element can, for example, have the shape of a cone, funnel, tube, the shape of a Venturi nozzle or the like. In a further advantageous embodiment, the number of openings and / or the diameter of the openings in the separating element varies. As a result, on the one hand, by varying the number of openings, at least one area of the wall of the cooling channel, in particular at least one area on the underside of the piston crown and / or at least one area on the wall opposite the ring area, is sprayed with oil which is particularly exposed to high temperatures during fuel combustion. By varying the diameter of the opening in the separating element, on the other hand, it is possible for the jet width and / or the jet velocity of the exiting oil jet to be adapted from the opening of the respective temperature load of the piston.

In a further advantageous embodiment, the separating element is sealed to the wall of the cooling channel by means of at least one sealing element, preferably by means of an O-ring. If the unprocessed separating element is attached to the upper part and the upper part is connected to the separately machined lower part after the common processing of both the upper part and the separating element, it is possible that the gap forming between the separating element and the lower part is sealed by means of a sealing element are. Preferably, the surface of the lower part, which touches the sealing element directly, made particularly accurate fit. Also, the area of the separating element, which receives the sealing element, for example an O-ring, is made particularly precisely fitting. The separating element may, for example, have a groove or the like for receiving an O-ring. A tailor-made production means a production in which, for example, a particularly good surface quality and a particularly high accuracy of fit are achieved.

Alternatively, in an alternative advantageous embodiment, in which the separating element is fastened to the lower part, it is possible that the gap which forms between the upper part and the separating element after assembly of the piston is sealed with a sealing element, such as an O-ring. The coming into contact with the sealing element surface of the upper part is made particularly accurate fit. Also, the separating element can in this alternative Embodiment, for example, for receiving an O-ring have a groove or the like.

In a further preferred embodiment, the piston has at least one pin bore, which in addition to the function of receiving the pin also fills the oil inlet with oil. Alternatively or additionally, it is possible that the oil inlet of the piston can be filled via a separate oil supply.

Furthermore, the invention claims a method for producing a piston of an internal combustion engine, wherein the unprocessed separating element is positioned on the wall of the later cooling channel of the piston prior to processing of the piston so that the separating element works together with the piston during the production of the piston is, thereby eliminating the processing of the piston separate processing of the separating element.

The piston is preferably made of an upper part and a lower part.

The unprocessed separating element is preferably attached to the upper part, so that subsequently the separating element is processed together with the upper part. Alternatively, the unprocessed separating element is preferably fastened to the lower part, so that subsequently the separating element is processed together with the lower part.

The separating element is preferably sealed to the wall of the cooling channel by means of at least one sealing element, preferably by means of an O-ring.

The oil inlet of the piston is preferably filled with oil by means of at least one pin bore of the piston. Alternatively or additionally, it is possible that the Olzulauf of the piston is filled via a separate oil supply.

In the figure, a preferred embodiment according to the invention is shown. It shows

Figure 1: a piston according to the invention in section in side view. FIG. 1 shows a finished piston 1 of an internal combustion engine, which consists of a top part 2 and a bottom part 3. The upper part 2 has a peripheral over the circumference of the piston ring portion 4 with three annular grooves for receiving unillustrated piston rings, a combustion bowl 5 in the region of the piston head 14 and a part of the cooling channel 9 in the form of a recess. In this recess, the underside of the piston crown 14 can be seen according to FIG. The lower part 3 contains in the example a plurality of oil inlets 15, which open into a further recess which forms part of the cooling channel 9. Furthermore, the lower part 3 according to FIG. 1 has two bolt holes 6 which receive a bolt, by means of which a connecting rod 7 is connected to the lower part 3 or the piston 1. The two pin holes 6 also fill the oil feeds 15 continuously with oil.

In the exemplary embodiment according to FIG. 1, the upper part 2 is positioned on the lower part 3 in the region of a plurality of corresponding contact surfaces, the upper part 2 being fixedly connected to the lower part 3 by means of a plurality of screw connections 8.

Prior to assembly of the piston 1 according to Figure 1, an unprocessed separating element 10 is positioned on the wall of the cooling channel 9 of the unprocessed lower part 3, which has a plurality of openings 13 after its processing. By attaching the unprocessed separating element 10 to the unprocessed lower part 3, the separating element 10 in the context of processing the lower part 3 with editable, whereby the processing of the piston 1 separate processing of the separating element 10 is omitted. The attached to the lower part 3 separating element 10 is formed in the embodiment as a one-piece ring, so that the separating element 10, the cooling channel 9 over its entire circumference in two areas, namely a reduced cooling channel 9 ^' and a pressure chamber 1 1, divides. FIG. 1 shows the finished separating element 10.

The resulting between a part of the wall of the cooling channel 9 and the separator 10 pressure chamber 1 1 is filled with oil under pressure by means of the oil feeds 15. To seal the pressure chamber 1 1, the separator 10th sealed with the wall of the cooling channel 9 of the upper part 2 by means of an O-ring 12 which, like the separating element 10, circumscribes the entire cooling channel 9. This creates a sealed pressure chamber 1 1, which is connected via the openings 13 with the reduced cooling channel 9 ^' . The O-ring 12 is positioned according to FIG. 1 in a groove which has the processed separating element 10.

The openings 13 of the processed separating element 10 are nozzle-shaped, tubular in the example, according to FIG. In the embodiment, the number of openings 13 and the diameter of the openings 13 in the processed partition member 10 varies over the entire circumference of the cooling channel 9. As a result, areas of the cooling channel 9 ^'are particularly well cooled, in which the number of openings 13 is very high and the diameter of the openings 13 is suitably adapted for good cooling.

The production of the piston 1 according to FIG. 1 will be described in more detail below, which is produced inter alia from an upper part 2 and a lower part 3.

Before the production of the piston 1, an unprocessed separating element 10 and an unprocessed lower part 3 are produced on the one hand.

For the preparation of the piston 1, the unprocessed, designed as a ring separator 10 is positioned on the wall of the subsequent cooling channel 9 of the lower part 3 before the subsequent processing of the unprocessed lower part 3. The unprocessed separating element 10 is thus to be seen after the attachment to the unprocessed lower part 3 as a contour of the unprocessed lower part 3. Subsequently, the unprocessed separating element 10 attached to the unprocessed lower part 3 is processed together with the unprocessed lower part 3 in the course of the production of the lower part 3. This eliminates the separate processing of the unprocessed separating element 10 and the unprocessed lower part 3. The unprocessed separating element 10 has no openings 13. In the separating element 10, the openings 13 are thus introduced during processing and machined with. In addition to the processing of the separating element 10 as part of the processing of the lower part 3 and in the lower part of the third For example, the bolt holes 6, the oil feeds 15 and the shaft elements (not shown) of the piston 1 introduced and edited. The oil inlets 15 are holes in the embodiment.

Separately for the production of the lower part 3 together with the separating element 10, on the other hand, the upper part 2 is manufactured and processed. According to FIG. 1, as part of the processing of the upper part 2, for example, the combustion chamber trough 5 and the ring section 4 are introduced.

Both in the processing of the upper part 2 and the lower part 3 together with the separating element 10, the areas of the subsequent cooling channel 9 in the form of a respective recess and the corresponding bearing surfaces for upper part 2 and lower part 3 are introduced and processed. In particular, the region of the upper part 2 on the wall of the subsequent cooling channel 9 is machined to fit, to which an O-ring 12 for sealing the subsequent pressure chamber 1 1 is applied.

As part of the production and after assembly of the piston 1, the separating element 10 is sealed to the wall of the cooling channel 9 by means of at least the O-ring 12 according to Figure 1, which circulates as the separating element 10, the entire cooling channel 9. Under a precisely tailored processing is to understand a particularly good processing, in particular with regard to the surface quality and accuracy of fit.

After the manufacture and assembly of the piston 1 and during operation of the piston 1 in an internal combustion engine, the oil present in the pressure chamber 11 by means of the supply under pressure continuously exits the openings 13. For this purpose, the oil flows continuously with a certain pressure and a certain volume flow through the oil feeds 15 into the pressure chamber 1 1, so that a pressure in the pressure chamber 1 1 is formed, which escapes through the openings 13 by means of continuous ejection of the oil. As a result of the continuously generated pressure in the pressure chamber 11, the oil is distributed over the entire circumference of the pressure chamber 11 in the piston 1. By the oil exiting the openings 13 and at least to a portion of the wall of the reduced cooling channel 9 ^' , in particular at least a portion of the underside of the piston head 14 and at least a portion of the ring section 4 opposite wall, impinges, the piston 1 is continuous and well chilled. The targeted cooling of the piston 1 by means of the oil jets emerging from the openings 13 in particular reduces the surface temperature in the region of the combustion bowl 5 and the region of the ring section 4. In general, the temperature of the piston 1 during operation of the piston 1 in an internal combustion engine is also reduced by the escaping oil steels.

In order to achieve optimum cooling of the piston 1 during operation, the number of nozzles and their diameter is coordinated, the vote must be made so that the pressure at which the oil flows out of the pressure chamber 1 1 via the openings 13, prevents an oil carbon buildup in the region of the cooling channel 9.

The ejection of the located under pressure in the pressure chamber 1 1 oil from the pressure chamber 1 1 is further enhanced by a so-called shaker effect during the movement and operation of the piston 1 in the internal combustion engine. By means of the shaker effect, the oil is ejected from the pressure chamber 1 1 due to the upward and downward movement of the piston 1 in the internal combustion engine, but especially in the downward movement of the piston 1 in the direction of connecting rod 7, due to its inertia from the openings 13.

The ejected from the openings 13 in the reduced cooling channel 9 ^' oil is subject exclusively to the shaker effect. The ejected oil is then removed via not shown in the Figure 1 through holes from the reduced cooling channel 9 ^' and from the piston 1. LIST OF REFERENCE NUMBERS

1 piston

2 top part

3 lower part

4 ring game

5 combustion bowl

6 bolt hole

7 connecting rods

8 screw connection

9 cooling channel

9 ^' cooling channel (reduced)

10 separating element

1 1 pressure chamber

12 o-ring

13 opening

14 piston bottom

15 oil feed

Claims

PATENT APPLICATIONS

1 .

Piston (1) of an internal combustion engine, comprising a piston head (14) and a cooling channel (9), in which a separating element (10) with at least one opening (13) is positioned, whereby a pressure chamber (1 1) between a part of the wall of Cooling channel (9) and the separating element (10) is formed, which is filled with oil under pressure by means of at least one oil inlet (15), wherein the oil from the opening (13) emerges and at least on a region of the cooling channel (9 ^' ) occurs, such that the piston (1) can be cooled, characterized in that the unprocessed separating element (10) can be positioned on the wall of the later cooling channel (9) so that the separating element (10) can be machined in the course of the production of the piston (1) is, thereby eliminating the processing of the piston (1) separate processing of the separating element (10).

Second

Piston (1) according to claim 1, characterized in that the piston (1) consists of an upper part (2) and a lower part (3).

Third

Piston (1) according to claim 2, characterized in that the unprocessed separating element (10) on the upper part (2) is fixed, so that the separating element (10) in the context of processing the upper part (2) is machinable.

4th

Piston (1) according to claim 2, characterized in that the unprocessed separating element (10) on the lower part (3) is fixed, so that the separating element (10) in the context of processing the lower part (3) is editable.

5th

Piston (1) according to one of claims 1 to 4, characterized in that the unprocessed separating element (10) is annular, preferably formed as a one-piece ring.

6th

Piston (1) according to one of claims 1 to 5, characterized in that the opening (13) of the separating element (10) after the processing of the separating element (10) is nozzle-shaped.

7th

Piston (1) according to one of claims 1 to 6, characterized in that the number of openings (13) and / or the diameter of the openings (13) in the separating element (10) varies.

8th.

Piston (1) according to one of claims 1 to 7, characterized in that the separating element (10) is sealed to the wall of the cooling channel (9) by means of at least one sealing element, preferably by means of an O-ring (12).

9th

Piston (1) according to one of claims 1 to 8, characterized in that the piston (1) has at least one pin bore (6) which in addition to the function of receiving the bolt and the oil feed (15) filled with oil.

10th

Method for producing a piston (1) of an internal combustion engine, which after the production of the piston (1) is cooled by sprayed-on oil, wherein the oil from a pressure chamber (1 1) through at least one opening (13) of a separating element

(10), which is positioned in a cooling channel (9) of the piston (1) and thereby in the cooling channel (9) with oil via at least one oil inlet (15) can be filled pressure chamber

(1 1) between a part of the wall of the cooling channel (9) and the separating element (10) forms, at least targeted to a region of the cooling channel (9 ^' ) by generated pressure in the oil-filled pressure chamber (1 1) is injected, characterized characterized in that the unprocessed separating element (10) is positioned on the wall of the later cooling channel (9) of the piston (1) before machining the piston (1), so that the separating element (10) together with the piston (1) in the frame the preparation of the piston (1) is processed, thereby eliminating the machining of the piston (1) separate machining of the separating element (10).

1 1.

A method according to claim 10, characterized in that the piston (1) from an upper part (2) and a lower part (3) is produced.

12th

A method according to claim 1 1, characterized in that the unprocessed separating element (10) is fixed to the upper part (2), so that subsequently the separating element (10) is processed together with the upper part (2).

13th

A method according to claim 1 1, characterized in that the unprocessed separating element (10) on the lower part (3) is fixed, so that subsequently the separating element (10) is processed together with the lower part (3).

14th

Method according to one of claims 10 to 13, characterized in that the separating element (10) with the wall of the cooling channel (9) by means of at least one sealing element, preferably by means of an O-ring (12) is sealed.

15th

Method according to one of claims 10 to 14, characterized in that the oil feed (15) of the piston (1) by means of at least one pin bore (6) of the piston (1) is filled with oil.