EP2561205B1 - Piston upper part of an assembled or welded piston with extended cooling spaces - Google Patents

Piston upper part of an assembled or welded piston with extended cooling spaces Download PDF

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Publication number
EP2561205B1
EP2561205B1 EP11703395.1A EP11703395A EP2561205B1 EP 2561205 B1 EP2561205 B1 EP 2561205B1 EP 11703395 A EP11703395 A EP 11703395A EP 2561205 B1 EP2561205 B1 EP 2561205B1
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EP
European Patent Office
Prior art keywords
piston
recesses
piston upper
cooling
recess
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP11703395.1A
Other languages
German (de)
French (fr)
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EP2561205A1 (en
Inventor
Andreas Olma
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
KS Kolbenschmidt GmbH
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KS Kolbenschmidt GmbH
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Publication of EP2561205A1 publication Critical patent/EP2561205A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—PistonsĀ 
    • F02F3/0015—Multi-part pistons
    • F02F3/003—Multi-part pistons the parts being connected by casting, brazing, welding or clamping
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C9/00—Moulds or cores; Moulding processes
    • B22C9/10—Cores; Manufacture or installation of cores
    • B22C9/105—Salt cores
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—PistonsĀ 
    • F02F3/02—PistonsĀ  having means for accommodating or controlling heat expansion
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—PistonsĀ 
    • F02F3/16—PistonsĀ  having cooling means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—PistonsĀ 
    • F02F3/16—PistonsĀ  having cooling means
    • F02F3/20—PistonsĀ  having cooling means the means being a fluid flowing through or along piston
    • F02F3/22—PistonsĀ  having cooling means the means being a fluid flowing through or along piston the fluid being liquid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—PistonsĀ 
    • F02F3/16—PistonsĀ  having cooling means
    • F02F3/20—PistonsĀ  having cooling means the means being a fluid flowing through or along piston
    • F02F3/22—PistonsĀ  having cooling means the means being a fluid flowing through or along piston the fluid being liquid
    • F02F3/225—PistonsĀ  having cooling means the means being a fluid flowing through or along piston the fluid being liquid the liquid being directed into blind holes
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49229—Prime mover or fluid pump making
    • Y10T29/49231—I.C. [internal combustion] engine making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49229—Prime mover or fluid pump making
    • Y10T29/49249—Piston making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49229—Prime mover or fluid pump making
    • Y10T29/49249—Piston making
    • Y10T29/49252—Multi-element piston making
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T29/00—Metal working
    • Y10T29/49—Method of mechanical manufacture
    • Y10T29/49229—Prime mover or fluid pump making
    • Y10T29/49249—Piston making
    • Y10T29/49256—Piston making with assembly or composite article making

Definitions

  • the invention relates to a one-piece and two-piece piston of an internal combustion engine and a method for producing such pistons according to the respective preambles of the independent claims.
  • the combustion temperatures and the combustion pressures are increased in order to optimize the combustion, so that the upper part of the piston in particular is subjected to high thermal loads.
  • the operating temperature of the piston of such internal combustion engines can exceed the permissible limits of the piston material, associated with the risk of heat aging in which the alloy of the piston material loses strength and dimensional stability.
  • pistons are used in which an annular cooling channel is integrated, in which a partial amount of the lubricating oil of the internal combustion engine is injected as a coolant via an injection nozzle, flows through the cooling channel and then exits.
  • the DE 197 50 021 A1 discloses a cooling duct piston which, in the area of the annular field, encloses an annular cooling duct, radially offset from a lateral surface.
  • the coolant flowing through the cooling channel effects heat dissipation, the effectiveness of this liquid cooling being essentially determined by the volume throughput of the cooling medium through the cooling channel.
  • the DE 41 18 400 A1 a built-up piston which, starting from the cooling channel, includes cooling slots running in the direction of the piston crown with walls running parallel to one another.
  • the invention is based on the object of optimizing the cooling effect of the upper piston part of a one-piece and of a two-part piston in thermally highly stressed zones by means of an inexpensive measure and accordingly specifying a piston and a method for producing such pistons.
  • the present invention provides an upper piston part of a one-piece and a two-piece piston with integrated recesses according to the features of claims 1 and 2, as well as a method for producing the recesses according to the features of claims 12, 13 and 14.
  • the two-part piston is designed as a liquid-cooled piston, consisting of a lower piston part and an upper piston part having a combustion chamber bowl. These piston components are supported by joining webs that are radially spaced from one another and form a parting plane and are preferably joined together in a materially bonded manner, preferably by means of a welded connection, or preferably frictionally, preferably by means of a screw connection.
  • the assembled piston is thus preferably assembled from an upper piston part and a lower piston part, for example by means of a screw connection, or preferably welded together, for example by means of a welded connection.
  • the upper piston part is an annular one that extends into the lower piston part Introduced cooling channel, which is in communication with an inner cooling space via connecting channels.
  • the upper piston part includes recesses that are oriented in the direction of a piston crown and designed as a blind hole and connected to the cooling channel.
  • the liquid-cooled piston of an internal combustion engine consists of a piston lower part and a piston upper part having a combustion chamber bowl, the piston being designed as a one-piece piston that has no parting plane.
  • the at least one circumferential recess starting from the cooling duct is designed in the upper piston part so that its walls widen in a conically increasing manner.
  • a maximum cross-section is established in the area of greatest depth of the recess.
  • the invention advantageously increases the depth of the cooling space through which the coolant flows, while maintaining defined wall thicknesses, and thus optimizes the cooling of the upper piston part.
  • a preferred structural shape of the recess according to the invention follows, at a distance, a central contour of the trough-shaped combustion bowl introduced in the piston head.
  • the shaker effect can be improved and consequently the cooling effect can be increased.
  • the size and extent of the recess according to the invention, which forms an extension of the cooling duct, is advantageously not limited by design-related requirements, for example the position and arrangement of the separation plane between the lower piston part and the upper piston part or the cooling duct, but can, for example, expand in a targeted manner in the direction of the combustion bowl .
  • the recesses designed according to the invention are preferably intended for piston tops with a relatively small combustion bowl diameter in order to optimally cool the resulting large wall thicknesses and material accumulations in the piston crown.
  • the exhaust gas requirements (Tier 3 and IMO) for assembled pistons with a small combustion bowl diameter can advantageously be achieved in conjunction with the measures to optimize the cooling of the upper piston part. It is advantageous to combine the upper piston part designed according to the invention with existing, tried and tested lower piston parts. In the case of a one-piece, liquid-cooled piston of an internal combustion engine, the type of piston lower part and the piston upper part are also designed to be suitable, as described above.
  • the size and extent of the recess is not limited by the outer diameter of the joining webs or the support surfaces in the area of the plane of separation between the upper piston part and the lower piston part. Rather, the measure according to the invention enables the recess according to the invention intended for cooling to be expanded into the thermally highly stressed zone.
  • the cross-sectional profile in the recess base consequently exceeds the cross-sectional profile in the area of a transition from the recess to the cooling channel due to the conical widening.
  • the piston head preferably includes a plurality of recesses distributed around the circumference and connected to the cooling channel. These recesses, designed as blind holes and specifically enlarging the cooling space, bring about improved, efficient cooling of the upper piston part.
  • the recesses lead, at least locally, to reduced wall thicknesses of the upper piston part, as compared with the combustion chamber bowl, the ring zone, the top land and the piston crown. Due to coordinated wall thicknesses between the recesses designed according to the invention and the adjacent thermally A structurally stable upper piston part that can withstand the highest demands is realized in areas subject to high loads.
  • the measure according to the invention reduces the component temperature to a level below the flash point of conventional cooling oils, which at the same time reduces the risk of coking for the lubricating oil of the internal combustion engine, which is preferably used as the coolant.
  • the piston upper part and consequently the entire piston are suitable for higher combustion temperatures and pressures, i.e. can be used in internal combustion engines with high power density.
  • the large-volume, inexpensive to manufacture recesses, particularly in the case of small combustion bowl diameters advantageously reduce the weight of the upper piston part.
  • a preferred embodiment of the recesses, according to the invention, which widen conically over the longitudinal extent provides that these are designed, distributed circumferentially in the upper piston part, in particular as slots, bores or channels.
  • webs formed by the material of the upper piston part are provided between the recesses and the cooling channel.
  • walls or support ribs can also be used, the walls or support ribs differing from the webs in their respective shape.
  • the cold room is expanded spatially.
  • the adjacent recesses designed according to the invention are made in the upper piston part in opposite directions, alternately in matching or differing geometric sizes and / or inclinations to one another. This measure enables a targeted extension of the recesses up to thermally highly stressed zones without the risk of component weakening.
  • the walls of the recess are inclined at an angle of inclination " ā‡ , ā‡ " between 0 Ā° to 40 Ā°, preferably ā‡ 15 Ā°, to a longitudinal piston axis to achieve largely matching wall thicknesses compared to the thermally highly stressed zones.
  • ā‡ , ā‡ angle of inclination
  • ā‡ angle of inclination
  • ā‡ ā‡ 15 Ā°
  • the conically expanding recesses are each provided with a rounded recess base that has a positive effect on the structural strength.
  • D maximum diameter of the tool used for the cutting process, for example a milling tool, for the rounded contour
  • the double-rounded recess base can be designed in a stepped manner.
  • the recess base can be a strongly undulating surface, which creates an enlarged surface, or as a finely undulating surface Surface. Additional machining manufacturing steps, for example milling cuts, reduce the stepped transition between the bulges, whereby the surface of the bulges is qualitatively improved by a lower waviness on the surface and whereby the size of the surface is reduced. It is thus possible to create a finely wavy surface with a larger number of cuts.
  • the invention includes a beveled recess base. The recesses in the cooling duct also lead to increased turbulence of the coolant in the cooling duct.
  • the cooling chamber can be adapted to the shape of the depression in the combustion chamber depression.
  • the adaptation and configuration of the recess base is possible by means of the shape of the casting mold body, the shape of which in certain areas is the negative shape of the shape of the recess base.
  • the recesses which are preferably designed as channels, bores or slots, to be arranged symmetrically or asymmetrically on the circumference in the upper piston part.
  • the position, orientation and size of the recess can be adapted to the different thermal loads. For example, it is advisable to design the cooling space or cross-sectional volume of the recess on the pressure side (DS) to be different from the corresponding cross-sectional volume on the counterpressure side (GDS) of the piston upper part.
  • the location and interpretation of the The recess is made in such a way that a weakening of the strength of the upper piston part is avoided. According to a method according to the invention according to claim 12, the following steps are provided for producing the recesses.
  • a casting mold body corresponding to the shape of the recesses preferably a salt core, is fixed in position in the casting mold intended for the upper piston part. After the upper part of the piston has been cast and cooled, the casting mold body is removed by rinsing.
  • a casting mold body corresponding to the shape of the recesses preferably a salt core, is fixed in position in the casting mold intended for the one-piece piston, which has a piston upper part and a piston lower part.
  • the casting mold body is removed by rinsing.
  • Another alternative method for producing the recesses provides for mechanical, three-dimensional machining.
  • a turning and milling process is preferably suitable for this, with which cavities are introduced to represent recesses in the piston upper part. It is also a good idea to represent the recesses by means of milling or drilling tools.
  • Figure 1 shows a longitudinal section through an upper piston part 1, which is, for example, a component made from a steel alloy by means of a forging process.
  • the upper piston part 1 can also be made from aluminum, an aluminum alloy or an iron alloy.
  • the upper piston part 1 can also be produced by means of any other desired forming process or primary forming process.
  • the piston upper part 1 forms together with an in Figure 1 Piston lower part not shown, for example, a two-part piston that is built with a friction fit or welded with a material fit and is liquid-cooled.
  • the upper piston part 1 is supported on corresponding joining webs of the lower piston part via two circumferential joining webs 2, 3 that are radially offset from one another.
  • All joining webs together form a separation plane 4 via which the lower piston part and the upper piston part 1 are permanently connected to one another by means of a frictional connection, preferably by means of a screw connection, or by means of a material connection, preferably by means of a welded connection.
  • a frictional connection preferably by means of a screw connection
  • a material connection preferably by means of a welded connection.
  • a combustion chamber bowl 7 which is delimited on the outside by a stepped bowl rim 8, is introduced concentrically to a piston longitudinal axis 5 in a piston head 6 of the upper piston part 1.
  • the upper piston part 1 is enclosed by a top land 9 which adjoins the piston crown 6 and which is adjoined by an annular zone 10 intended to accommodate piston rings.
  • an annular cooling channel 11 is provided in the area of the parting plane 4, which extends into the lower piston part and through which coolant, in particular lubricating oil of the internal combustion engine, circulates when the internal combustion engine is in operation.
  • the cooling medium enters the cooling channel 11 via an inlet and leaves the cooling channel 11 via a plurality of connection channels 15, also known as transfer bores, via an outlet.
  • the coolant supply can alternatively also take place via the center of the piston, that is to say the inner cooling space 16.
  • the coolant is conducted into the cooling channel 11 via the connecting channels 15 and then flows out of the cooling channel 11 via drainage bores.
  • the cooling channel 11 is connected to a plurality of recesses 12 distributed around the circumference and aligned in the direction of the piston head 6.
  • These recesses 12, which are distributed around the circumference and are introduced in the manner of blind holes, are designed as channels, bores and / or slots and enlarge the cooling space in the piston upper part 1, which is acted upon by the coolant.
  • the recesses 12 widen conically up to a maximum at a recess bottom 14.
  • the recesses 12 are connected to a central inner cooling chamber 16 positioned below the combustion bowl 7 via connecting channels 15 positioned on the circumference.
  • Figure 2 illustrates the geometric design of the recess 12 in an enlarged illustration.
  • the recesses 12 distributed circumferentially in the upper piston part 1 can alternatively also be designed as cavities running around the periphery.
  • the recess 12 according to the exemplary embodiment is made in the piston upper part 1 subsequently during production by means of the forging process by means of mechanical three-dimensional machining.
  • the recess 12 forms a stepped recess base 14.
  • the dome-like recess base forming a bowl vault. 14 includes a double-rounded contour enclosing the radius "R".
  • the depth of the recess base 14 located between the radii "R" in the recess 12 can be adjusted by the number of cuts.
  • the inner wall 17, which is closer to the piston longitudinal axis 5 in the radial direction, and the outer wall 18, which is farther away from the piston longitudinal axis 5 in the radial direction, are to be closed to the recess 12, in particular to adapt to the structural design of the upper piston part 1 as well as almost identical wall thicknesses compared to the thermally heavily loaded zones the piston longitudinal axis 5 is inclined.
  • the angle of inclination ā‡ of the inner wall 17 and the angle of inclination ā‡ of the outer wall 18, the inner wall 17 and the outer wall 18 being inclined opposite to one another, can be designed to be the same or different from one another.
  • Figure 3 shows the top view of the upper piston part 1 of a two-part piston in the direction of the two joining webs 2, 3.
  • the upper piston part 1 has several slot-shaped recesses 19, in the example five slot-shaped recesses 19, arranged tangentially around the piston longitudinal axis 5 according to Figure 3 on.
  • the tangential rotation around the piston longitudinal axis 5 is also known under the term radial rotation around the piston longitudinal axis 5.
  • the piston upper part 1 has more than five or fewer than five slot-shaped recesses 19.
  • the inner cooling space 16 is also shown, around which the five slot-shaped recesses 19 are arranged distributed around the circumference.
  • the slot-shaped recesses 19 are not connected to one another, so that a spacing in the form of webs 20 exists between the respective slot-shaped recesses 19.
  • the cooling space By varying the slot depth of the respective cooling slots 21, 22 of the recess 12, it is possible for the cooling space to be adapted to the bowl shape of the combustion bowl 7. The degree of smoothing is achieved by the number of slots between cooling slot 21 and cooling slot 22. In Figure 5 the inner cooling space 16 is also shown for the sake of clarity.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Description

Die Erfindung betrifft einen einteiligen und zweiteiligen Kolben einer Brennkraftmaschine und Verfahren zur Herstellung solcher Kolben gemƤƟ den jeweiligen Oberbegriffen der unabhƤngigen PatentansprĆ¼che.The invention relates to a one-piece and two-piece piston of an internal combustion engine and a method for producing such pistons according to the respective preambles of the independent claims.

Zur Einhaltung von Emissionsgrenzwerten bzw. zur Erreichung von Emissionszielen und Verbrauchszielen werden zur Optimierung der Verbrennung die Verbrennungstemperaturen und die VerbrennungsdrĆ¼cke angehoben, wodurch insbesondere das Kolbenoberteil thermisch stark beansprucht wird. Die Betriebstemperatur des Kolbens derartiger Brennkraftmaschinen kann die zulƤssigen Grenzen von dem Kolbenwerkstoff Ć¼berschreiten, verbunden mit der Gefahr einer WƤrmealterung, bei der die Legierung des Kolbenwerkstoffs an Festigkeit und Formsteifigkeit verliert. Um die thermischen Belastungen des Kolbens zu minimieren, werden Kolben eingesetzt, in denen ein ringfƶrmiger KĆ¼hlkanal integriert ist, in dem als KĆ¼hlmittel eine Teilmenge von dem Schmierƶl der Brennkraftmaschine Ć¼ber eine EinspritzdĆ¼se eingespritzt wird, den KĆ¼hlkanal durchstrƶmt und dann austritt. Die DE 197 50 021 A1 offenbart einen KĆ¼hlkanalkolben, der im Bereich des Ringfeldes radial versetzt zu einer MantelflƤche einen ringfƶrmigen KĆ¼hlkanal einschlieƟt. Das durch den KĆ¼hlkanal strƶmende KĆ¼hlmittel bewirkt eine WƤrmeabfuhr, wobei die Wirksamkeit dieser FlĆ¼ssigkeitskĆ¼hlung wesentlich von dem Volumendurchsatz des KĆ¼hlmediums durch den KĆ¼hlkanal bestimmt wird.In order to comply with emission limit values or to achieve emission targets and consumption targets, the combustion temperatures and the combustion pressures are increased in order to optimize the combustion, so that the upper part of the piston in particular is subjected to high thermal loads. The operating temperature of the piston of such internal combustion engines can exceed the permissible limits of the piston material, associated with the risk of heat aging in which the alloy of the piston material loses strength and dimensional stability. In order to minimize the thermal loads on the piston, pistons are used in which an annular cooling channel is integrated, in which a partial amount of the lubricating oil of the internal combustion engine is injected as a coolant via an injection nozzle, flows through the cooling channel and then exits. The DE 197 50 021 A1 discloses a cooling duct piston which, in the area of the annular field, encloses an annular cooling duct, radially offset from a lateral surface. The coolant flowing through the cooling channel effects heat dissipation, the effectiveness of this liquid cooling being essentially determined by the volume throughput of the cooling medium through the cooling channel.

Mit zunehmender spezifischer Leistung der Brennkraftmaschine ist es erforderlich, bekannte Konzepte von flĆ¼ssigkeitsgekĆ¼hlten Kolben zu optimieren. ZusƤtzlich zu einem ringfƶrmigen KĆ¼hlkanal ist es daher erforderlich, weitere Bereiche des Kolbens gezielt mit KĆ¼hlmittel zu beaufschlagen. Zur Realisierung dieser MaƟnahme zeigt die DE 41 18 400 A1 einen gebauten Kolben, der vom KĆ¼hlkanal ausgehend, in Richtung des Kolbenbodens verlaufende KĆ¼hlschlitze mit zueinander parallel verlaufenden Wandungen einschlieƟt.As the specific power of the internal combustion engine increases, it is necessary to optimize known concepts of liquid-cooled pistons. In addition to an annular cooling channel, it is therefore necessary to specifically apply coolant to other areas of the piston. To implement this measure, the DE 41 18 400 A1 a built-up piston which, starting from the cooling channel, includes cooling slots running in the direction of the piston crown with walls running parallel to one another.

Der Erfindung liegt die Aufgabe zu Grunde, die KĆ¼hlwirkung des Kolbenoberteils eines einteiligen und eines zweiteiligen Kolbens in thermisch hochbelasteten Zonen durch eine kostengĆ¼nstige MaƟnahme zu optimieren und dementsprechend einen Kolben und Verfahren zur Herstellung solcher Kolben anzugeben.The invention is based on the object of optimizing the cooling effect of the upper piston part of a one-piece and of a two-part piston in thermally highly stressed zones by means of an inexpensive measure and accordingly specifying a piston and a method for producing such pistons.

Ausgehend von dem Stand der Technik stellt die vorliegende Erfindung ein Kolbenoberteil eines einteiligen und eines zweiteiligen Kolbens mit integrierten Ausnehmungen gemƤƟ den Merkmalen des Patentanspruchs 1 und 2, sowie Verfahren zur Herstellung der Ausnehmungen gemƤƟ den Merkmalen der PatentansprĆ¼che 12, 13 und 14 bereit.Based on the prior art, the present invention provides an upper piston part of a one-piece and a two-piece piston with integrated recesses according to the features of claims 1 and 2, as well as a method for producing the recesses according to the features of claims 12, 13 and 14.

Der zweiteilige Kolben ist als ein flĆ¼ssigkeitsgekĆ¼hlter Kolben, bestehend aus einem Kolbenunterteil und einem eine Brennraummulde aufweisenden Kolbenoberteil, ausgefĆ¼hrt. Diese Kolbenbauteile sind Ć¼ber radial zueinander beabstandete, eine Trennungsebene bildende FĆ¼gestege abgestĆ¼tzt und vorzugsweise stoffschlĆ¼ssig, bevorzugt mittels einer SchweiƟverbindung, oder vorzugsweise reibschlĆ¼ssig, bevorzugt mittels einer Schraubenverbindung, zusammengefĆ¼gt. Somit ist der zusammengefĆ¼gte Kolben aus einem Kolbenoberteil und Kolbenunterteil vorzugsweise zusammengebaut, beispielsweise mittels Schraubenverbindung, oder vorzugsweise zusammengeschweiƟt, beispielsweise mittels SchweiƟverbindung. In dem Kolbenoberteil ist ein ringfƶrmiger, sich bis in das Kolbenunterteil erstreckender KĆ¼hlkanal eingebracht, der Ć¼ber VerbindungskanƤle mit einem inneren KĆ¼hlraum in Verbindung steht. Zur KĆ¼hlraumvergrĆ¶ĆŸerung schlieƟt das Kolbenoberteil in Richtung eines Kolbenbodens ausgerichtete, als Sackloch ausgefĆ¼hrte, mit dem KĆ¼hlkanal verbundene Ausnehmungen ein.The two-part piston is designed as a liquid-cooled piston, consisting of a lower piston part and an upper piston part having a combustion chamber bowl. These piston components are supported by joining webs that are radially spaced from one another and form a parting plane and are preferably joined together in a materially bonded manner, preferably by means of a welded connection, or preferably frictionally, preferably by means of a screw connection. The assembled piston is thus preferably assembled from an upper piston part and a lower piston part, for example by means of a screw connection, or preferably welded together, for example by means of a welded connection. In the upper piston part is an annular one that extends into the lower piston part Introduced cooling channel, which is in communication with an inner cooling space via connecting channels. To enlarge the cooling space, the upper piston part includes recesses that are oriented in the direction of a piston crown and designed as a blind hole and connected to the cooling channel.

GemƤƟ dem Patentanspruch 2 ist es auch mƶglich, dass der flĆ¼ssigkeitsgekĆ¼hlte Kolben einer Brennkraftmaschine aus einem Kolbenunterteil und einem eine Brennraummulde aufweisenden Kolbenoberteil besteht, wobei der Kolben als ein einteiliger Kolben ausgefĆ¼hrt ist, der keine Trennungsebene aufweist.According to claim 2, it is also possible that the liquid-cooled piston of an internal combustion engine consists of a piston lower part and a piston upper part having a combustion chamber bowl, the piston being designed as a one-piece piston that has no parting plane.

Zur Lƶsung der Problemstellung ist gemƤƟ der Erfindung nach Anspruch 1 und Anspruch 2 vorgesehen, die zumindest eine von dem KĆ¼hlkanal ausgehende, umlaufend eingebrachte Ausnehmung in dem Kolbenoberteil so auszubilden, dass deren Wandungen sich konisch ansteigend aufweiten. Aufgrund der sich einstellenden Spreizung der Wandungen stellt sich ein maximaler Querschnitt in dem Bereich grĆ¶ĆŸter Tiefe der Ausnehmung ein. Vorteilhaft vergrĆ¶ĆŸert die Erfindung unter Einhaltung definierter WandstƤrken gegenĆ¼ber bisher bekannten Lƶsungen den von dem KĆ¼hlmittel durchstrƶmten, in der Tiefe erweiterten KĆ¼hlraum und optimiert somit die KĆ¼hlung des Kolbenoberteils. Eine bevorzugte konstruktive Formgebung der erfindungsgemƤƟen Ausnehmung folgt beabstandet einer zentrischen Kontur der wannenfƶrmig in dem Kolbenboden eingebrachten Brennraummulde. Verbunden mit einem groƟvolumigen, die KĆ¼hlmittelaufnahme vergrĆ¶ĆŸernden Hohlraum der Ausnehmung kann die Shakerwirkung verbessert und folglich die KĆ¼hlwirkung gesteigert werden. Die GrĆ¶ĆŸe und die Erstreckung der erfindungsgemƤƟen, eine Erweiterung des KĆ¼hlkanals bildende Ausnehmung ist vorteilhaft nicht durch konstruktiv bedingte Vorgaben, beispielsweise die Lage und Anordnung der Trennungsebene zwischen dem Kolbenunterteil und dem Kolbenoberteil oder dem KĆ¼hlkanal begrenzt, sondern kann sich beispielsweise gezielt in Richtung der Brennraummulde erweitern. Die erfindungsgemƤƟ gestalteten Ausnehmungen sind bevorzugt fĆ¼r Kolbenoberteile mit einem relativ kleinen Brennraummulden-Durchmesser bestimmt, um die sich einstellenden groƟen WandstƤrken und MaterialanhƤufungen in dem Kolbenboden optimal zu kĆ¼hlen. Damit kann eine Verkokung bis zu einem Abbrand sowie eine Festigkeitsminderung des Werkstoffs vermieden werden. Vorteilhaft kƶnnen in Verbindung mit den MaƟnahmen zur Optimierung der KĆ¼hlung des Kolbenoberteils die Abgasforderungen (Tier 3 und IMO) fĆ¼r gebaute Kolben mit einem kleinen Brennraummulden-Durchmesser erreicht werden. Vorteilhaft bietet es sich an, das erfindungsgemƤƟ gestaltete Kolbenoberteil mit vorhandenen erprobten Kolbenunterteilen zu kombinieren. Bei einem als einteilig ausgefĆ¼hrten flĆ¼ssigkeitsgekĆ¼hlten Kolben einer Brennkraftmaschine ist die Art des Kolbenunterteils und des Kolbenoberteils ebenso, wie vorhergehend beschrieben, passend gestaltet.To solve the problem, according to the invention according to claim 1 and claim 2, the at least one circumferential recess starting from the cooling duct is designed in the upper piston part so that its walls widen in a conically increasing manner. As a result of the spreading of the walls, a maximum cross-section is established in the area of greatest depth of the recess. The invention advantageously increases the depth of the cooling space through which the coolant flows, while maintaining defined wall thicknesses, and thus optimizes the cooling of the upper piston part. A preferred structural shape of the recess according to the invention follows, at a distance, a central contour of the trough-shaped combustion bowl introduced in the piston head. In conjunction with a large-volume cavity of the recess which increases the coolant absorption, the shaker effect can be improved and consequently the cooling effect can be increased. The size and extent of the recess according to the invention, which forms an extension of the cooling duct, is advantageously not limited by design-related requirements, for example the position and arrangement of the separation plane between the lower piston part and the upper piston part or the cooling duct, but can, for example, expand in a targeted manner in the direction of the combustion bowl . The recesses designed according to the invention are preferably intended for piston tops with a relatively small combustion bowl diameter in order to optimally cool the resulting large wall thicknesses and material accumulations in the piston crown. In this way, coking up to the point of burning and a reduction in strength of the material can be avoided. The exhaust gas requirements (Tier 3 and IMO) for assembled pistons with a small combustion bowl diameter can advantageously be achieved in conjunction with the measures to optimize the cooling of the upper piston part. It is advantageous to combine the upper piston part designed according to the invention with existing, tried and tested lower piston parts. In the case of a one-piece, liquid-cooled piston of an internal combustion engine, the type of piston lower part and the piston upper part are also designed to be suitable, as described above.

GemƤƟ der Erfindung wird die GrĆ¶ĆŸe und die Erstreckung der Ausnehmung nicht durch den ƤuƟeren Durchmesser der FĆ¼gestege beziehungsweise der AbstĆ¼tzflƤchen im Bereich der Trennungsebene zwischen dem Kolbenoberteil und dem Kolbenunterteil begrenzt. Vielmehr ermƶglicht die erfindungsgemƤƟe MaƟnahme die zur KĆ¼hlung bestimmte erfindungsgemƤƟe Ausnehmung bis in thermisch hochbelasteten Zone auszudehnen. Das Querschnittsprofil in dem Ausnehmungsgrund Ć¼bertrifft aufgrund der konischen Aufweitung folglich das Querschnittsprofil im Bereich eines Ɯbergangs der Ausnehmung zu dem KĆ¼hlkanal. Bevorzugt schlieƟt der Kolbenboden mehrere umfangsverteilt positionierte, mit dem KĆ¼hlkanal in Verbindung stehende Ausnehmungen ein. Diese als Sackloch ausgefĆ¼hrten, den KĆ¼hlraum gezielt vergrĆ¶ĆŸernden Ausnehmungen bewirken eine verbesserte, effiziente KĆ¼hlung des Kolbenoberteils. Dabei fĆ¼hren die Ausnehmungen zumindest lokal zu reduzierten WandstƤrken des Kolbenoberteils, wie gegenĆ¼ber der Brennraummulde, dem Ringfeld, dem Feuersteg sowie dem Kolbenboden. Bedingt durch abgestimmte WandstƤrken zwischen den erfindungsgemƤƟ ausgefĆ¼hrten Ausnehmungen und den benachbarten thermisch stark beanspruchten Zonen wird ein strukturfestes, hƶchsten Anforderungen standhaltendes Kolbenoberteil realisiert.According to the invention, the size and extent of the recess is not limited by the outer diameter of the joining webs or the support surfaces in the area of the plane of separation between the upper piston part and the lower piston part. Rather, the measure according to the invention enables the recess according to the invention intended for cooling to be expanded into the thermally highly stressed zone. The cross-sectional profile in the recess base consequently exceeds the cross-sectional profile in the area of a transition from the recess to the cooling channel due to the conical widening. The piston head preferably includes a plurality of recesses distributed around the circumference and connected to the cooling channel. These recesses, designed as blind holes and specifically enlarging the cooling space, bring about improved, efficient cooling of the upper piston part. In this case, the recesses lead, at least locally, to reduced wall thicknesses of the upper piston part, as compared with the combustion chamber bowl, the ring zone, the top land and the piston crown. Due to coordinated wall thicknesses between the recesses designed according to the invention and the adjacent thermally A structurally stable upper piston part that can withstand the highest demands is realized in areas subject to high loads.

Die erfindungsgemƤƟe MaƟnahme reduziert die Bauteiltemperatur auf ein Niveau unterhalb von dem Flammpunkt Ć¼blicher KĆ¼hlƶle, wodurch sich gleichzeitig die Gefahr einer Verkokung fĆ¼r das bevorzugt als KĆ¼hlmittel eingesetzte Schmierƶl der Brennkraftmaschine verringert. AuƟerdem besteht keine Gefahr, dass sich eine isolierende, die KĆ¼hlwirkung herabsetzende Ɩlkohleschicht bildet, sowie eine nachteilige thermische Kolben-Deformation aufgrund einer abgesenkten Festigkeit des Kolbenwerkstoffs einstellt. Durch die entscheidend verbesserte WƤrmeabfuhr und damit KĆ¼hlwirkung der erfindungsgemƤƟen Ausnehmung ist das Kolbenoberteil und folglich der gesamte Kolben fĆ¼r hƶhere Verbrennungstemperaturen und VerbrennungsdrĆ¼cke, d.h. in Brennkraftmaschinen mit hoher Leistungsdichte einsetzbar. AuƟerdem verringern die groƟvolumig gestalteten, kostengĆ¼nstig herstellbaren Ausnehmungen insbesondere bei kleinen Brennraummulden-Durchmessern vorteilhaft das Gewicht des Kolbenoberteils.The measure according to the invention reduces the component temperature to a level below the flash point of conventional cooling oils, which at the same time reduces the risk of coking for the lubricating oil of the internal combustion engine, which is preferably used as the coolant. In addition, there is no risk of an insulating oil carbon layer which reduces the cooling effect forming, and of disadvantageous thermal piston deformation due to a reduced strength of the piston material. Due to the decisively improved heat dissipation and thus the cooling effect of the recess according to the invention, the piston upper part and consequently the entire piston are suitable for higher combustion temperatures and pressures, i.e. can be used in internal combustion engines with high power density. In addition, the large-volume, inexpensive to manufacture recesses, particularly in the case of small combustion bowl diameters, advantageously reduce the weight of the upper piston part.

Eine bevorzugte AusfĆ¼hrungsform der erfindungsgemƤƟ sich Ć¼ber die LƤngserstreckung konisch aufweitenden Ausnehmungen sieht vor, dass diese im Kolbenoberteil umfangsverteilt insbesondere als Schlitze, Bohrungen oder KanƤle gestaltet sind. Dabei sind zwischen den Ausnehmungen und dem KĆ¼hlkanal von dem Material des Kolbenoberteils gebildete Stege vorgesehen. Alternativ zu den Stegen kƶnnen auch Wandungen oder StĆ¼tzrippen verwendet werden, wobei sich die Wandungen oder StĆ¼tzrippen durch ihre jeweilige Form von den Stegen unterscheiden. Zur Erzielung einer hohen Strukturfestigkeit des Kolbenoberteils bietet es sich an, die konisch aufgeweiteten Ausnehmungen als tortenfƶrmige KĆ¼hlraumkammern mit einer Wabenstruktur auszubilden, die gleichzeitig die KĆ¼hleigenschaften positiv beeinflusst und die zu einer VergrĆ¶ĆŸerung der KĆ¼hloberflƤche fĆ¼hrt. ZusƤtzlich wird dadurch auch der KĆ¼hlraum rƤumlich erweitert.A preferred embodiment of the recesses, according to the invention, which widen conically over the longitudinal extent provides that these are designed, distributed circumferentially in the upper piston part, in particular as slots, bores or channels. In this case, webs formed by the material of the upper piston part are provided between the recesses and the cooling channel. As an alternative to the webs, walls or support ribs can also be used, the walls or support ribs differing from the webs in their respective shape. In order to achieve a high structural strength of the piston upper part, it is advisable to design the conically widened recesses as pie-shaped cooling chamber chambers with a honeycomb structure, which at the same time positively influences the cooling properties and which leads to an increase in the cooling surface. In addition, the cold room is expanded spatially.

Einer weiteren konstruktiven Auslegung gemƤƟ werden die erfindungsgemƤƟ gestalteten, benachbarten Ausnehmungen entgegengesetzt wechselweise in Ć¼bereinstimmenden oder voneinander abweichenden geometrischen GrĆ¶ĆŸen und/oder Neigungen zueinander in dem Kolbenoberteil eingebracht. Diese MaƟnahme ermƶglicht eine gezielte Erstreckung der Ausnehmungen bis in thermisch hoch belastete Zonen, ohne die Gefahr einer BauteilschwƤchung.According to a further structural design, the adjacent recesses designed according to the invention are made in the upper piston part in opposite directions, alternately in matching or differing geometric sizes and / or inclinations to one another. This measure enables a targeted extension of the recesses up to thermally highly stressed zones without the risk of component weakening.

GemƤƟ einer bevorzugten Auslegung sind zur Erzielung weitestgehend Ć¼bereinstimmender WandstƤrken gegenĆ¼ber den thermisch stark belasteten Zonen die Wandungen der Ausnehmung in einem Neigungswinkel "Ī±, Ī²" zwischen 0Ā° bis 40Ā°, vorzugsweise von ā‰¤ 15Ā° zu einer KolbenlƤngsachse geneigt ausgerichtet. Dem konstruktiven Aufbau des Kolbenbodens angepasst, bietet es sich weiterhin an, die Neigungswinkel von gegenĆ¼berliegenden Wandungen, insbesondere einer inneren Wandung und einer ƤuƟeren Wandung, Ć¼bereinstimmend oder voneinander abweichend auszulegen.According to a preferred design, the walls of the recess are inclined at an angle of inclination "Ī±, Ī²" between 0 Ā° to 40 Ā°, preferably ā‰¤ 15 Ā°, to a longitudinal piston axis to achieve largely matching wall thicknesses compared to the thermally highly stressed zones. Adapted to the design of the piston head, it is also advisable to design the angles of inclination of opposing walls, in particular an inner wall and an outer wall, to match or differ from one another.

Zur kostenoptimierten Fertigung und Vermeidung einer BauteilschwƤchung ist vorgesehen, die sich konisch spreizenden Ausnehmungen jeweils mit einem gerundeten, die Strukturfestigkeit positiv beeinflussenden Ausnehmungsgrund zu versehen. FĆ¼r die gerundete Kontur ist bevorzugt ein Radius "R" zwischen 1,5 mm und D/2 (D = maximaler Durchmesser des verwendeten Werkzeugs fĆ¼r das spanabhebende Verfahren, beispielsweise eines FrƤswerkzeugs, fĆ¼r die gerundete Kontur) vorgesehen. Alternativ dazu bietet es sich an, den Ausnehmungsgrund mit einer doppelt gerundeten, ein kuppelartiges Muldengewƶlbe bildenden Kontur zu versehen. Weiterhin kann zur Anpassung an den konstruktiven Aufbau des Kolbenbodens der doppelt gerundete Ausnehmungsgrund gestuft gestaltet werden. Der Ausnehmungsgrund kann dabei als stark wellenfƶrmige OberflƤche, wodurch eine vergrĆ¶ĆŸerte OberflƤche erzeugt wird, oder als eine fein wellenfƶrmige OberflƤche ausgefĆ¼hrt werden. Durch zusƤtzliche spanabhebende Fertigungsschritte, beispielsweise FrƤsschnitte, wird der gestufte Ɯbergang zwischen den Wƶlbungen verringert, wodurch die OberflƤche der Wƶlbungen qualitativ durch eine geringere Welligkeit auf der OberflƤche verbessert wird und wodurch die GrĆ¶ĆŸe der OberflƤche verringert wird. Somit ist es mƶglich, durch eine grĆ¶ĆŸere Anzahl der Schnitte eine feinwellige OberflƤche zu erzeugen. Alternativ zu einer gerundeten Endkontur schlieƟt die Erfindung einen abgeschrƤgt ausgebildeten Ausnehmungsgrund ein. Durch die Ausnehmungen in dem KĆ¼hlkanal kommt es zusƤtzlich auch zu einer verstƤrkten Verwirbelung des KĆ¼hlmittels in dem KĆ¼hlkanal. Durch eine Anpassung der OberflƤche des Ausnehmungsgrundes und eine Verkleinerung des Durchmessers des Ausnehmungsgrundes ist es mƶglich, die Emissionen bei dem Betrieb des Kolbens zu verringern bzw. zu optimieren. Auch kƶnnen durch die Anpassung des gestuften Ɯbergangs die Emissionen beim Betrieb verringert werden. Durch die Variation der Tiefe der Ausnehmung, von dem Kolbenunterteil in Richtung Kolbenoberteil gesehen, kann eine Anpassung des KĆ¼hlraums an die Form der Mulde der Brennraummulde erfolgen. Bei einem einteiligen Kolben ist die Anpassung und Ausgestaltung des Ausnehmungsgrundes mittels der Form des GieƟformkƶrpers mƶglich, dessen Form in bestimmten Bereichen die Negativ-Form der Form des Ausnehmungsgrundes ist.For cost-optimized production and avoidance of component weakening, the conically expanding recesses are each provided with a rounded recess base that has a positive effect on the structural strength. For the rounded contour, a radius "R" between 1.5 mm and D / 2 (D = maximum diameter of the tool used for the cutting process, for example a milling tool, for the rounded contour) is preferably provided. As an alternative to this, it is advisable to provide the bottom of the recess with a double-rounded contour that forms a dome-like hollow vault. Furthermore, to adapt to the structural design of the piston head, the double-rounded recess base can be designed in a stepped manner. The recess base can be a strongly undulating surface, which creates an enlarged surface, or as a finely undulating surface Surface. Additional machining manufacturing steps, for example milling cuts, reduce the stepped transition between the bulges, whereby the surface of the bulges is qualitatively improved by a lower waviness on the surface and whereby the size of the surface is reduced. It is thus possible to create a finely wavy surface with a larger number of cuts. As an alternative to a rounded end contour, the invention includes a beveled recess base. The recesses in the cooling duct also lead to increased turbulence of the coolant in the cooling duct. By adapting the surface of the recess base and reducing the diameter of the recess base, it is possible to reduce or optimize the emissions during operation of the piston. By adapting the stepped transition, emissions during operation can also be reduced. By varying the depth of the recess, viewed from the lower piston part in the direction of the upper piston part, the cooling chamber can be adapted to the shape of the depression in the combustion chamber depression. In the case of a one-piece piston, the adaptation and configuration of the recess base is possible by means of the shape of the casting mold body, the shape of which in certain areas is the negative shape of the shape of the recess base.

Eine weitere Ausgestaltung der Erfindung sieht vor, die bevorzugt als KanƤle, Bohrungen oder Schlitze ausgebildeten Ausnehmungen umfangsseitig symmetrisch oder unsymmetrisch in dem Kolbenoberteil anzuordnen. Die Lage, Ausrichtung und GrĆ¶ĆŸe der Ausnehmung kann dabei den unterschiedlichen thermischen Belastungen angepasst werden. Beispielsweise bietet es sich an, das KĆ¼hlraum- bzw. Querschnittsvolumen der Ausnehmung auf der Druckseite (DS) gegenĆ¼ber dem entsprechenden Querschnittsvolumen auf der Gegendrucksseite (GDS) des Kolbenoberteils voneinander abweichend auszulegen. Die Lage und Auslegung der Ausnehmung erfolgt so, dass eine SchwƤchung der Festigkeit des Kolbenoberteils vermieden wird.
GemƤƟ einem erfindungsgemƤƟen Verfahren nach Anspruch 12 sind zur Herstellung der Ausnehmungen folgende Schritte vorgesehen. ZunƤchst wird ein der Form der Ausnehmungen entsprechender GieƟformkƶrper, vorzugsweise ein Salzkern, in die fĆ¼r das Kolbenoberteil bestimmte GieƟform lagefixiert. Nach erfolgtem Guss und Erkalten des Kolbenoberteils wird der GieƟformkƶrper durch AusspĆ¼len entfernt.Another embodiment of the invention provides for the recesses, which are preferably designed as channels, bores or slots, to be arranged symmetrically or asymmetrically on the circumference in the upper piston part. The position, orientation and size of the recess can be adapted to the different thermal loads. For example, it is advisable to design the cooling space or cross-sectional volume of the recess on the pressure side (DS) to be different from the corresponding cross-sectional volume on the counterpressure side (GDS) of the piston upper part. The location and interpretation of the The recess is made in such a way that a weakening of the strength of the upper piston part is avoided.
According to a method according to the invention according to claim 12, the following steps are provided for producing the recesses. First, a casting mold body corresponding to the shape of the recesses, preferably a salt core, is fixed in position in the casting mold intended for the upper piston part. After the upper part of the piston has been cast and cooled, the casting mold body is removed by rinsing.

GemƤƟ einem weiteren alternativen erfindungsgemƤƟen Verfahren nach Anspruch 13 sind zur Herstellung der Ausnehmungen folgende Schritte bei einem einteiligen Kolben vorgesehen. ZunƤchst wird ein der Form der Ausnehmungen entsprechender GieƟformkƶrper, vorzugsweise ein Salzkern, in die fĆ¼r den einteiligen Kolben, der ein Kolbenoberteil und ein Kolbenunterteil aufweist, bestimmte GieƟform lagefixiert. Nach erfolgtem Guss und Erkalten des einteiligen Kolbens wird der GieƟformkƶrper durch AusspĆ¼len entfernt.According to a further alternative method according to the invention according to claim 13, the following steps are provided for producing the recesses in a one-piece piston. First, a casting mold body corresponding to the shape of the recesses, preferably a salt core, is fixed in position in the casting mold intended for the one-piece piston, which has a piston upper part and a piston lower part. After the one-piece piston has been cast and cooled, the casting mold body is removed by rinsing.

Ein weiteres alternatives Verfahren zur Herstellung der Ausnehmungen sieht eine mechanische, dreidimensionale zerspannende Bearbeitung vor. Dazu eignet sich bevorzugt eine Dreh- und FrƤsbearbeitung, mit der HohlrƤume zur Darstellung von Ausnehmungen in dem Kolbenoberteil eingebracht werden. AuƟerdem bietet es sich an, die Ausnehmungen mittels einer FrƤsung oder mit Bohrwerkzeugen darzustellen.Another alternative method for producing the recesses provides for mechanical, three-dimensional machining. A turning and milling process is preferably suitable for this, with which cavities are introduced to represent recesses in the piston upper part. It is also a good idea to represent the recesses by means of milling or drilling tools.

Ein beispielhaft ausgestaltetes Kolbenoberteil gemƤƟ der Erfindung, auf den diese jedoch nicht beschrƤnkt ist, ist im Folgenden beschrieben und anhand der Figuren erlƤutert.An exemplary designed upper piston part according to the invention, to which this is not limited, is described below and explained with reference to the figures.

Es zeigen:

Figur 1:
ein Kolbenoberteil in einem LƤngsschnitt mit einer erfindungsgemƤƟ gestalteten Ausnehmung,
Figur 2:
ein Detail des Kolbenoberteils gemƤƟ Figur 1 in einem vergrĆ¶ĆŸerten MaƟstab,
Figur 3:
die Draufsicht auf ein Kolbenoberteil mit mehreren schlitzfƶrmigen Ausnehmungen,
Figur 4:
eine rƤumliche Darstellung von KĆ¼hlschlitzen in einem Kolbenoberteil und
Figur 5:
eine rƤumliche Darstellung eines Kolbenoberteils mit erweiterten KĆ¼hlschlitzen.
Show it:
Figure 1:
an upper piston part in a longitudinal section with a recess designed according to the invention,
Figure 2:
a detail of the piston top according to Figure 1 on an enlarged scale,
Figure 3:
the top view of an upper piston part with several slot-shaped recesses,
Figure 4:
a three-dimensional representation of cooling slots in a piston upper part and
Figure 5:
a three-dimensional representation of an upper piston part with expanded cooling slots.

Figur 1 zeigt einen LƤngsschnitt durch ein Kolbenoberteil 1, bei dem es sich beispielsweise um ein aus einer Stahllegierung mittels eines Schmiedeverfahrens hergestelltes Bauteil handelt. Alternativ kann das Kolbenoberteil 1 auch aus Aluminium, aus einer Aluminiumlegierung oder aus einer Eisenlegierung hergestellt werden. Alternativ kann das Kolbenoberteil 1 auch mittels eines beliebigen anderen Umformverfahrens oder Urformverfahrens hergestellt werden. Das Kolbenoberteil 1 bildet gemeinsam mit einem in Figur 1 nicht abgebildeten Kolbenunterteil einen beispielsweise reibschlĆ¼ssig gebauten oder stoffschlĆ¼ssig geschweiƟten zweiteiligen Kolben, der flĆ¼ssigkeitsgekĆ¼hlt ist. Ɯber zwei radial zueinander versetzte, umlaufende FĆ¼gestege 2, 3 ist das Kolbenoberteil 1 an korrespondierenden FĆ¼gestegen des Kolbenunterteils abgestĆ¼tzt. Alle FĆ¼gestege bilden gemeinsam eine Trennungsebene 4, Ć¼ber die das Kolbenunterteil und das Kolbenoberteil 1 mittels einer reibschlĆ¼ssigen Verbindung, bevorzugt mittels einer Schraubenverbindung, oder mittels einer stoffschlĆ¼ssigen Verbindung, bevorzugt mittels einer SchweiƟverbindung, dauerfest miteinander verbunden sind. Zum anderen ist das Kolbenunterteil und das Kolbenoberteil 1 mittels der Trennungsebene 4 formschlĆ¼ssig aufeinander aufliegend. Konzentrisch zu einer KolbenlƤngsachse 5 ist in einem Kolbenboden 6 des Kolbenoberteils 1 eine Brennraummulde 7 eingebracht, die auƟenseitig von einem gestuften Muldenrand 8 begrenzt ist. Das Kolbenoberteil 1 wird von einem sich an den Kolbenboden 6 anschlieƟenden Feuersteg 9 umschlossen, an den sich ein zur Aufnahme von Kolbenringen bestimmtes Ringfeld 10 anschlieƟt. Zur KĆ¼hlung des Kolbenoberteils 1 ist im Bereich der Trennungsebene 4 ein ringfƶrmiger KĆ¼hlkanal 11 vorgesehen, der sich bis in das Kolbenunterteil erstreckt und durch den im Betriebszustand der Brennkraftmaschine KĆ¼hlmittel, insbesondere Schmierƶl der Brennkraftmaschine, zirkuliert. Dazu tritt das KĆ¼hlmedium Ć¼ber einen Einlass in den KĆ¼hlkanal 11 ein und verlƤsst den KĆ¼hlkanal 11 Ć¼ber mehrere VerbindungskanƤle 15, auch bekannt unter dem Namen Ɯbertrittsbohrungen, Ć¼ber einen Auslass. Der KĆ¼hlmittelzulauf kann alternativ auch Ć¼ber die Kolbenmitte, das heiƟt den innen KĆ¼hlraum 16, erfolgen. Dabei wird das KĆ¼hlmittel Ć¼ber die VerbindungskanƤle 15 in den KĆ¼hlkanal 11 geleitet und flieƟt anschlieƟend aus dem KĆ¼hlkanal 11 Ć¼ber Ablaufbohrungen ab. Der KĆ¼hlkanal 11 steht mit mehreren umfangsverteilt eingebrachten, in Richtung des Kolbenbodens 6 ausgerichteten Ausnehmungen 12 in Verbindung. Diese umfangsverteilt angeordneten, sacklochartig eingebrachten Ausnehmungen 12 sind als KanƤle, Bohrungen und/oder Schlitze ausgebildet und vergrĆ¶ĆŸern den von dem KĆ¼hlmittel beaufschlagten KĆ¼hlraum im Kolbenoberteil 1. Zur GewƤhrleistung einer ausreichenden Steifigkeit des Kolbenbodens 1 sind in einem Ɯbergangsbereich zwischen dem KĆ¼hlkanal 11 und den Ausnehmungen 12 Stege 13 vorgesehen. Von dem KĆ¼hlkanal 11 ausgehend erweitern sich die Ausnehmungen 12 konisch bis zu einem Maximum an einem Ausnehmungsgrund 14. Ɯber umfangsseitig positionierte VerbindungskanƤle 15 sind die Ausnehmungen 12 mit einem zentralen, unterhalb der Brennraummulde 7 positionierten inneren KĆ¼hlraum 16 verbunden. Figure 1 shows a longitudinal section through an upper piston part 1, which is, for example, a component made from a steel alloy by means of a forging process. Alternatively, the upper piston part 1 can also be made from aluminum, an aluminum alloy or an iron alloy. Alternatively, the upper piston part 1 can also be produced by means of any other desired forming process or primary forming process. The piston upper part 1 forms together with an in Figure 1 Piston lower part not shown, for example, a two-part piston that is built with a friction fit or welded with a material fit and is liquid-cooled. The upper piston part 1 is supported on corresponding joining webs of the lower piston part via two circumferential joining webs 2, 3 that are radially offset from one another. All joining webs together form a separation plane 4 via which the lower piston part and the upper piston part 1 are permanently connected to one another by means of a frictional connection, preferably by means of a screw connection, or by means of a material connection, preferably by means of a welded connection. On the other hand it is The lower piston part and the upper piston part 1 rest positively on one another by means of the parting plane 4. A combustion chamber bowl 7, which is delimited on the outside by a stepped bowl rim 8, is introduced concentrically to a piston longitudinal axis 5 in a piston head 6 of the upper piston part 1. The upper piston part 1 is enclosed by a top land 9 which adjoins the piston crown 6 and which is adjoined by an annular zone 10 intended to accommodate piston rings. To cool the upper piston part 1, an annular cooling channel 11 is provided in the area of the parting plane 4, which extends into the lower piston part and through which coolant, in particular lubricating oil of the internal combustion engine, circulates when the internal combustion engine is in operation. For this purpose, the cooling medium enters the cooling channel 11 via an inlet and leaves the cooling channel 11 via a plurality of connection channels 15, also known as transfer bores, via an outlet. The coolant supply can alternatively also take place via the center of the piston, that is to say the inner cooling space 16. The coolant is conducted into the cooling channel 11 via the connecting channels 15 and then flows out of the cooling channel 11 via drainage bores. The cooling channel 11 is connected to a plurality of recesses 12 distributed around the circumference and aligned in the direction of the piston head 6. These recesses 12, which are distributed around the circumference and are introduced in the manner of blind holes, are designed as channels, bores and / or slots and enlarge the cooling space in the piston upper part 1, which is acted upon by the coolant. To ensure sufficient rigidity of the piston crown 1, there are a transition area between the cooling channel 11 and the recesses 12 Web 13 is provided. Starting from the cooling channel 11, the recesses 12 widen conically up to a maximum at a recess bottom 14. The recesses 12 are connected to a central inner cooling chamber 16 positioned below the combustion bowl 7 via connecting channels 15 positioned on the circumference.

Figur 2 verdeutlicht die geometrische Gestaltung der Ausnehmung 12 in einer vergrĆ¶ĆŸerten Abbildung. Die umfangsverteilt in dem Kolbenoberteil 1 eingebrachten Ausnehmungen 12 kƶnnen alternativ auch als begrenzt umlaufende HohlrƤume gestaltet werden. Bevorzugt wird die Ausnehmung 12 gemƤƟ dem AusfĆ¼hrungsbeispiel nachtrƤglich bei der Herstellung mittels des Schmiedeverfahrens mittels einer mechanischen dreidimensionalen zerspannenden Bearbeitung im Kolbenoberteil 1 eingebracht. Alternativ dazu bietet es sich bei einem mittels eines GieƟverfahrens hergestellten Kolbenoberteil 1 an, die Ausnehmung 12 mittels eines GieƟformkƶrpers in das Kolbenoberteil 1 einzuformen . Zur Darstellung weitestgehend Ć¼bereinstimmender WandstƤrken zu den AuƟenkonturen des Kolbenoberteils 1, beispielsweise gegenĆ¼ber dem Kolbenboden 6, dem Feuersteg 9 sowie dem Muldenrand 8 der Brennraummulde 7, bildet die Ausnehmung 12 einen gestuften Ausnehmungsgrund 14. Der domartig, ein Muldengewƶlbe bildende Ausnehmungsgrund. 14 schlieƟt eine doppelt gerundete, den Radius "R" einschlieƟende Kontur ein. Durch die Anzahl der Schnitte kann die Tiefe des zwischen den Radien "R" befindliche Ausnehmungsgrund 14 in der Ausnehmung 12 eingestellt werden. Insbesondere zur Anpassung an den konstruktiven Aufbau des Kolbenoberteils 1 sowie nahezu Ć¼bereinstimmender WandstƤrken gegenĆ¼ber den thermisch stark belasteten Zonen sind die zur KolbenlƤngsachse 5 in radialer Richtung nƤher liegende innere Wandung 17 und die zur KolbenlƤngsachse 5 in radialer Richtung weiter weg liegende ƤuƟere Wandung18 der Ausnehmung 12 zu der KolbenlƤngsachse 5 jeweils geneigt. Der Neigungswinkel Ī± der inneren Wandung 17 und der Neigungswinkel Ī² der ƤuƟeren Wandung 18, wobei die innere Wandung 17 und die ƤuƟer Wandung 18 entgegengesetzt zueinander geneigt sind, kƶnnen dabei gleich oder voneinander abweichend ausgelegt sein. Figure 2 illustrates the geometric design of the recess 12 in an enlarged illustration. The recesses 12 distributed circumferentially in the upper piston part 1 can alternatively also be designed as cavities running around the periphery. Preferably, the recess 12 according to the exemplary embodiment is made in the piston upper part 1 subsequently during production by means of the forging process by means of mechanical three-dimensional machining. As an alternative to this, in the case of an upper piston part 1 produced by means of a casting process, it is advisable to mold the recess 12 into the upper piston part 1 by means of a casting mold body. To show largely matching wall thicknesses to the outer contours of the upper piston part 1, for example opposite the piston crown 6, the top land 9 and the bowl edge 8 of the combustion bowl 7, the recess 12 forms a stepped recess base 14. The dome-like recess base forming a bowl vault. 14 includes a double-rounded contour enclosing the radius "R". The depth of the recess base 14 located between the radii "R" in the recess 12 can be adjusted by the number of cuts. The inner wall 17, which is closer to the piston longitudinal axis 5 in the radial direction, and the outer wall 18, which is farther away from the piston longitudinal axis 5 in the radial direction, are to be closed to the recess 12, in particular to adapt to the structural design of the upper piston part 1 as well as almost identical wall thicknesses compared to the thermally heavily loaded zones the piston longitudinal axis 5 is inclined. The angle of inclination Ī± of the inner wall 17 and the angle of inclination Ī² of the outer wall 18, the inner wall 17 and the outer wall 18 being inclined opposite to one another, can be designed to be the same or different from one another.

In Figur 3 ist ein weiteres AusfĆ¼hrungsbeispiel eines Kolbenoberteils 1 gemƤƟ der Erfindung dargestellt. Gleiche Bauteile sind mit gleichen Bezugsziffern versehen und neue Bauteile sind mit neuen Bezugsziffern benannt.In Figure 3 a further embodiment of an upper piston part 1 according to the invention is shown. The same components are given the same reference numbers and new components are given new reference numbers.

Figur 3 zeigt die Draufsicht auf das Kolbenoberteil 1 eines zweiteiligen Kolbens in Richtung der beiden FĆ¼gestege 2, 3. Das Kolbenoberteil 1 weist mehrere mit einem bestimmten Radius um die KolbenlƤngsachse 5 tangential angeordnete schlitzfƶrmige Ausnehmungen 19, im Beispiel fĆ¼nf schlitzfƶrmige Ausnehmungen 19, gemƤƟ Figur 3 auf. Bekannt ist der tangentiale Umlauf um die KolbenlƤngsachse 5 auch unter dem Begriff des radialen Umlaufs um die KolbenlƤngsachse 5. Alternativ ist es mƶglich, dass das Kolbenoberteil 1 mehr als fĆ¼nf oder weniger als fĆ¼nf schlitzfƶrmige Ausnehmungen 19 aufweist. Figure 3 shows the top view of the upper piston part 1 of a two-part piston in the direction of the two joining webs 2, 3. The upper piston part 1 has several slot-shaped recesses 19, in the example five slot-shaped recesses 19, arranged tangentially around the piston longitudinal axis 5 according to Figure 3 on. The tangential rotation around the piston longitudinal axis 5 is also known under the term radial rotation around the piston longitudinal axis 5. Alternatively, it is possible that the piston upper part 1 has more than five or fewer than five slot-shaped recesses 19.

In Figur 3 ist zur Verdeutlichung zusƤtzlich der innere KĆ¼hlraum 16 mit dargestellt, um den die fĆ¼nf schlitzfƶrmigen Ausnehmungen 19 umfangsverteilt angeordnet sind. Dabei sind die schlitzfƶrmigen Ausnehmungen 19 nicht miteinander verbunden, so dass jeweils ein Abstand in Form von Stegen 20 zwischen den jeweiligen schlitzfƶrmigen Ausnehmungen 19 existiert.In Figure 3 For clarity, the inner cooling space 16 is also shown, around which the five slot-shaped recesses 19 are arranged distributed around the circumference. The slot-shaped recesses 19 are not connected to one another, so that a spacing in the form of webs 20 exists between the respective slot-shaped recesses 19.

In Figur 4 sind zwei KĆ¼hlschlitze 21, 22 mit WellenkĆ¼hlung in einem Kolbenoberteil 1 eines zweiteiligen Kolbens dargestellt, wobei die beiden KĆ¼hlschlitze 21, 22 der dargestellten Ausnehmung 12 zugeordnet sind. Es ist dabei mƶglich den Muldendurchmesser des jeweiligen KĆ¼hlschlitzes 21, 22 noch zu verkleinern oder eine Stufenmulde einzubringen. Durch die WellenkĆ¼hlung wird zum einen eine VergrĆ¶ĆŸerung der KĆ¼hloberflƤche und eine Verwirbelung erreicht. In Figur 4 ist zusƤtzlich zur Verdeutlichung auch der innere KĆ¼hlraum 16 mit dargestellt.In Figure 4 two cooling slots 21, 22 with shaft cooling are shown in an upper piston part 1 of a two-part piston, the two cooling slots 21, 22 being assigned to the recess 12 shown. It is possible to further reduce the trough diameter of the respective cooling slot 21, 22 or to introduce a step trough. On the one hand, the shaft cooling results in an enlargement of the cooling surface and a turbulence. In Figure 4 the inner cooling space 16 is also shown for the sake of clarity.

In Figur 5 sind zwei erweitere KĆ¼hlschlitze 21, 22 mit geglƤtteter OberflƤche dargestellt, wobei die beiden KĆ¼hlschlitze 21, 22 der dargestellten Ausnehmung 12 zugeordnet sind. Es ist dabei mƶglich, den Muldendurchmesser noch zu verkleinern oder die Stufenmulde zu bearbeiten, die zu einer Verringerung von Emissionen verwendet werden.In Figure 5 two expanded cooling slots 21, 22 with a smoothed surface are shown, the two cooling slots 21, 22 being assigned to the illustrated recess 12. It is possible to make the trough diameter smaller or to edit the step trough, which is used to reduce emissions.

Durch die Variation der Schlitztiefe der jeweiligen KĆ¼hlschlitze 21, 22 der Ausnehmung 12 ist es mƶglich, dass eine Anpassung des KĆ¼hlraums an die Muldenform der Brennraummulde 7 erfolgt. Der Grad der GlƤttung wird durch die Anzahl der Schlitze zwischen KĆ¼hlschlitz 21 und KĆ¼hlschlitz 22 erreicht. In Figur 5 ist zusƤtzlich zur Verdeutlichung auch der innere KĆ¼hlraum 16 mit dargestellt.By varying the slot depth of the respective cooling slots 21, 22 of the recess 12, it is possible for the cooling space to be adapted to the bowl shape of the combustion bowl 7. The degree of smoothing is achieved by the number of slots between cooling slot 21 and cooling slot 22. In Figure 5 the inner cooling space 16 is also shown for the sake of clarity.

BezugszeichenlisteList of reference symbols

11
KolbenoberteilPiston top
22
FĆ¼gestegJoining web
33
FĆ¼gestegJoining web
44th
TrennungsebeneLevel of separation
55
KolbenlƤngsachsePiston longitudinal axis
66th
KolbenbodenPiston crown
77th
BrennraummuldeCombustion bowl
88th
MuldenrandTrough edge
99
FeuerstegTop land
1010
RingfeldRing field
1111
KĆ¼hlkanalCooling duct
1212
AusnehmungRecess
1313
Stegweb
1414th
AusnehmungsgrundRecess reason
1515th
VerbindungskanalConnection channel
1616
Innerer KĆ¼hlraumInner fridge
1717th
Innere WandungInner wall
1818th
ƄuƟere WandungOuter wall
1919th
schlitzfƶrmige Ausnehmungslot-shaped recess
2020th
Stegweb
2121st
KĆ¼hlschlitzCooling slot
2222nd
KĆ¼hlschlitzCooling slot

Claims (16)

  1. Piston of an internal combustion engine, designed as a liquid-cooled piston, composed of a piston lower part and of a piston upper part (1) which has a combustion chamber depression (7), which piston lower part and piston upper part are supported and joined together by means of joining webs (2, 3) which are radially spaced apart from one another and which form a parting plane (4), wherein, in the piston upper part (1), there is formed a ring-shaped cooling channel (11) which extends into the piston lower part and which is connected via connecting channels (15) to an internal cooling chamber (16) and which has recesses (12) which are oriented in the direction of a piston crown (6) and which are formed as blind holes and which form cooling chambers, characterized in that the recesses (12) are designed to conically widen proceeding from the cooling channel (11) to a recess base (14) of the respective recess (12).
  2. Piston of an internal combustion engine, designed as a single-part liquid-cooled piston, having a piston lower part and a piston upper part (1) which has a combustion chamber depression (7), wherein, in the piston upper part (1), there is formed a ring-shaped cooling channel (11) which is connected via connecting channels (15) to an internal cooling chamber (16) and which has recesses (12) which are oriented in the direction of a piston crown (6) and which are designed as blind holes and which form cooling chambers, characterized in that the recesses (12) are designed to conically widen proceeding from the cooling channel (11) to a recess base (14) of the respective recess (12).
  3. Piston according to Claim 1, characterized in that the piston upper part (1) and the piston lower part are joined together cohesively, preferably by means of a welded connection, or in frictionally locking fashion, preferably by means of a screw connection.
  4. Piston according to any of Claims 1 to 3, characterized in that the recesses (12) which are formed in a circumferentially distributed manner in the piston upper part (1) and which are designed to rise in a conical shape are formed as bores, channels and/or slots.
  5. Piston according to any of Claims 1 to 4, characterized in that webs (13, 20) formed from a material of the piston upper part (1) are provided between the recesses (12) and the cooling channel (11).
  6. Piston according to any of Claims 1 to 5, characterized in that the recesses (12) formed in a circumferentially distributed manner in the piston upper part (1) form a honeycomb structure.
  7. Piston according to any of Claims 1 to 6, characterized in that recesses (12) formed adjacently in the piston upper part (1) are arranged so as to be inclined alternately radially inwards or radially outwards.
  8. Piston according to any of Claims 1 to 7, characterized in that the recesses (12) have oppositely inclined walls, in particular an inner wall (17) and an outer wall (18), the corresponding or mutually different angles of inclination "Ī±, Ī²" of which amount to between 0Ā° to 40Ā°.
  9. Piston according to any of Claims 1 to 8, characterized in that the recesses (12) have a recess base (14) which is of rounded or bevelled form with a radius "R" between 1.5 mm and D/2.
  10. Piston according to any of Claims 1 to 9, characterized in that the recesses (12) include a recess base (14) which is doubly rounded and/or rounded in a stepped manner.
  11. Piston according to any of Claims 1 to 10, characterized in that the conically widened recesses (12) formed as a bore, channel or slot are integrated in a circumferentially symmetrical or asymmetrical manner in the piston upper part (1).
  12. Method for producing a piston upper part (1) of a liquid-cooled piston of an internal combustion engine, which piston upper part is joined together with a piston lower part, wherein the piston upper part (1) has a combustion chamber depression (7) and a cooling channel (11) which is connected to recesses (12) which are oriented in the direction of a piston crown (6) and which are formed as blind holes, characterized in that, for the production of the recesses (12), the following steps are provided:
    - inserting a casting mould body which corresponds to the shape of the recess (12) and which is designed to conically widen proceeding from the cooling channel (11) to a recess base (14) of the respective recess (12) and which, prior to a casting process, is positioned in a casting mould designed for the piston upper part (1);
    - removing the casting mould body after casting has been performed, and cooling the piston upper part (12) by rinsing.
  13. Method for producing a single-piece liquid-cooled piston of an internal combustion engine, having a piston upper part (1) and a piston lower part, wherein the piston upper part (1) has a combustion chamber depression (7) and a cooling channel (11) which is connected to recesses (12) which are oriented in the direction of a piston crown (6) and which are formed as blind holes, characterized in that, for the production of the recesses (12), the following steps are provided:
    - inserting a casting mould body which corresponds to the shape of the recess (12) and which is designed to conically widen proceeding from the cooling channel (11) to a recess base (14) of the respective recess (12) and which, prior to a casting process, is positioned in a casting mould designed for the piston upper part (1) of the single-piece piston;
    - removing the casting mould body after casting has been performed, and cooling the piston upper part (12) of the single-piece piston by rinsing.
  14. Method for producing a piston upper part (1) of a liquid-cooled piston of an internal combustion engine, which piston upper part is joined together with a piston lower part, wherein the piston upper part (1) has a combustion chamber depression (7) and a cooling channel (11) which is connected to recesses (12) which are oriented in the direction of a piston crown (6) and which are formed as blind holes, characterized in that the production of the recesses (12) in the piston upper part (1) is performed by means of a mechanical, three-dimensional cutting machining process, such that the recesses (12) are designed to conically widen proceeding from the cooling channel (11) to a recess base (14) of the respective recess (12).
  15. Method according to Claim 14, characterized in that the piston upper part (1) is, prior to the formation of the recesses (12), produced by means of a deformation process, preferably by means of a forging process.
  16. Method according to Claim 12, 14 or 15, characterized in that the piston upper part (1) and the piston lower part are joined together cohesively, preferably by means of a welded connection, or in frictionally locking fashion, preferably by means of a screw connection.
EP11703395.1A 2010-04-19 2011-02-04 Piston upper part of an assembled or welded piston with extended cooling spaces Active EP2561205B1 (en)

Applications Claiming Priority (2)

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DE102010015568A DE102010015568A1 (en) 2010-04-19 2010-04-19 Piston upper part of a built or welded piston with extended cooling chambers
PCT/EP2011/000505 WO2011131266A1 (en) 2010-04-19 2011-02-04 Piston upper part of an assembled or welded piston with extended cooling spaces

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EP2561205A1 EP2561205A1 (en) 2013-02-27
EP2561205B1 true EP2561205B1 (en) 2020-09-23

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EP (1) EP2561205B1 (en)
KR (1) KR101867631B1 (en)
CN (1) CN102859165B (en)
DE (1) DE102010015568A1 (en)
WO (1) WO2011131266A1 (en)

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EP2561205A1 (en) 2013-02-27
KR20130062904A (en) 2013-06-13
WO2011131266A1 (en) 2011-10-27
CN102859165B (en) 2019-05-14
CN102859165A (en) 2013-01-02
DE102010015568A1 (en) 2011-10-20
KR101867631B1 (en) 2018-06-14
US8973548B2 (en) 2015-03-10
US20130032104A1 (en) 2013-02-07

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