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—Pistons 
• • 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—Pistons 
  • F02F3/0015—Multi-part pistons
  • F02F3/003—Multi-part pistons the parts being connected by casting, brazing, welding or clamping
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K1/00—Soldering, e.g. brazing, or unsoldering
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
  • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
  • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
  • F02B23/0672—Omega-piston bowl, i.e. the combustion space having a central projection pointing towards the cylinder head and the surrounding wall being inclined towards the cylinder center axis
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B23/00—Other engines characterised by special shape or construction of combustion chambers to improve operation
  • F02B23/02—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition
  • F02B23/06—Other engines characterised by special shape or construction of combustion chambers to improve operation with compression ignition the combustion space being arranged in working piston
  • F02B23/0678—Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets
  • F02B23/0693—Unconventional, complex or non-rotationally symmetrical shapes of the combustion space, e.g. flower like, having special shapes related to the orientation of the fuel spray jets the combustion space consisting of step-wise widened multiple zones of different depth
• • 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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies
• • 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
• • 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
  • Y10T29/49263—Piston making with assembly or composite article making by coating or cladding

Definitions

• the present invention relates to a multi-piece piston for an internal combustion engine and to a method for producing such a piston.
• connection of upper piston part and lower piston part can cause problems here, as explained in detail in EP 1 483 493 B1.
• the piston upper part and the piston lower part can, for example, be welded together or screwed together, wherein each of these connection techniques has specific advantages and disadvantages.
• From the international patent application PCT / DE2008 / 01394 it is also known to connect the upper piston part and the lower piston part by means of a solder material with each other. However, no information is given about the process parameters.
• the object of the present invention is to provide a simplified soldering method for producing a multi-part piston, which ensures a reliable solder joint between the piston top and piston lower part with the least possible effort.
• the solution consists in a method with the features of claim 1 and in a producible according to this method piston.
• a piston upper part and a lower piston part are produced, each with an inner support member with joining surfaces and an outer support member with joining surfaces, further that a high temperature solder material is applied in the region of at least one joining surface, that the piston upper part and the lower piston part by producing a Contact between the joining surfaces are assembled into a piston body, which is then placed in a vacuum oven and after evacuation of the vacuum furnace at a pressure of at most 10 ⁇ 2 mbar to a brazing temperature of at most 1300 0 C. is heated. Thereafter, the soldered flask is cooled at a pressure of at most 10 ⁇ 2 mbar until complete solidification of the high temperature soldering material.
• the desired material properties of the base material of the piston according to the invention are set after heating in a vacuum oven so that no further heat treatment, in particular no flash annealing, is more necessary and the base material after the soldering process still optimal values especially with regard to its strength, hardness and Has morphology.
• the process according to the invention is therefore of shorter duration and also less expensive than the processes known in the prior art.
• solder materials based on nickel, cobalt and / or copper are preferred.
• An example of a suitable solder material is the nickel-based solder L-BNi2 (according to EN 1044 or DIN 8513). With this solder material, especially when using AFP steel, a particularly strong and reliable connection between the piston upper part and piston lower part is achieved.
• the manner of applying the solder material is at the discretion of the person skilled in the art.
• the brazing material can, for example, be applied flatly to the at least one joining surface, in particular brushed on or printed by means of a stamp.
• the brazing material can also be introduced into at least one depot depression arranged in the region of at least one joining surface.
• the at least one depot recess can be designed to be particularly simple in manufacturing technology as a circumferential or rectilinear groove or as a dome-shaped depression.
• the upper piston part and / or the lower piston part are expediently provided with at least one centering surface in order to simplify the assembly of upper piston part and lower piston part and the correct orientation of piston upper part and lower piston part to ensure each other in a particularly simple manner.
• the at least one centering surface can also be provided with solder material. In particular, if the at least one centering surface meets at an angle to a joining surface, the solder material can be expediently mounted at an angle.
• the piston body is preferably heated in the vacuum furnace to a brazing temperature of at least 1000 0 C in order to achieve optimum distribution of the solder material by means of the action during the soldering operation capillary forces. It is expedient to keep the soldering temperature constant for at least 5 minutes.
• annular inner support elements can be provided which delimit an outer circumferential cooling channel and an inner cooling space.
• central inner support elements may also be provided which delimit an outer circumferential cooling channel which extends over a large area below the piston crown. In both cases, a particularly good cooling effect is caused by the cooling oil circulating in the cooling channel or cooling space.
• the piston according to the invention preferably consists of a steel base material with a ferritic-pearlitic structure, for example an AFP steel.
• the hardness of the base material desired by the method according to the invention is preferably 230 HB to 300 HB.
• FIG. 1 shows a section through a first embodiment of a piston according to the invention.
• FIG. 2 shows a section through a second embodiment of a piston according to the invention
• 3 shows a temperature-time diagram of the cooling phase of the method according to the invention.
• FIG. 1 shows a first exemplary embodiment of a piston 10 according to the invention in a representation as a composite piston body before the soldering process.
• the piston 10 is composed of a piston upper part 11 and a piston lower part 12, which are forged in the embodiment of an AFP steel.
• the piston upper part 11 has a combustion bowl 13, a peripheral top land 14 and a circumferential ring section 15.
• the piston lower part 12 has a piston shaft 16 and hubs 17 with hub bores 18 for receiving a piston pin (not shown).
• the upper piston part 11 and the lower piston part 12 form a peripheral outer cooling channel 19 and a central inner cooling space 21.
• the piston upper part 11 has an inner support element 22 and an outer support element 23.
• the inner support element 22 is arranged on the underside of the piston upper part 11 in an annular circumferential manner and has a joining surface 24.
• the inner support member 22 further forms a part of the peripheral wall of the inner cooling space 21.
• the outer support member 23 of the piston upper part 11 is formed in the embodiment within the ring portion 15 and has a joining surface 25.
• the inner support element 22 also has overflow channels 31 for the passage of cooling oil from the outer cooling channel 19 into the inner cooling space 21.
• the lower piston part 12 likewise has an inner support element 26 and an outer support element 27.
• the inner support element 26 is arranged circumferentially on the upper side of the piston lower part 12 and has a joining surface 28.
• the inner support member 26 further forms a part of the circumferential wall of the inner cooling space 21.
• the outer support member 27 is formed in the embodiment within the ring portion 15 and has a joining surface 29. Centering surface 32
• the inner support element 26 also has a circumferential centering surface 32, which in the exemplary embodiment is at right angles to the joining surface 28.
• a circumferential collar can be attached to the lower piston part 12, with which the joining surface 29 is widened radially and a larger surface area for the application of soldering. material offers. The federal government is after the soldering process, for example. In the finishing of the piston, removed again (not shown).
• the piston 10 is shown as a composite piston body before the soldering process.
• the high-temperature solder material is applied in the form of a solder deposits 33 in the angle between the joining surface 28 and centering surface 32 of the inner support member 26 of the piston base 12.
• the solder material can be applied as a circulating solder deposit 33 or in the form of a plurality of point or line-shaped solder deposits.
• solder material in the form of a thin layer on at least one of the outer joining surfaces 25 and 29 of the upper piston part 11 and / or lower piston part 12 is applied (not shown).
• the brazing material can also be applied exclusively flat on the joining surfaces, without providing Lotdepots.
• FIG. 2 shows a second exemplary embodiment of a piston 110 according to the invention in a representation as a composite piston body before the soldering process.
• the piston 110 essentially corresponds to the piston 10 according to FIG. 1.
• the upper piston part 11 and the lower piston part 12 only form a peripheral outer cooling channel 119.
• the piston upper part 11 on an inner support member 122, which is arranged centrally on the underside of the piston upper part 11 and with a joining surface 124.
• the lower piston part 12 has an inner support element 126, which is arranged centrally on the upper side of the piston lower part 12 and provided with a joining surface 128.
• the resulting cooling channel 119 extends particularly widely under the combustion bowl 13, resulting in an efficient cooling effect.
• the outer support member 123 of the piston upper part 11 is formed in this embodiment below the ring portion 15.
• the outer support element 123 has a joining surface 125 and a circumferential centering surface 134, which in the exemplary embodiment is at right angles to the joining surface 125.
• the outer support member 127 of the piston lower part 12 is accordingly also formed below the ring portion 15 and has a joining surface 129.
• the piston 110 is also shown as a composite piston body before the soldering process.
• the high-temperature solder material in the form of a solder deposit 133 is applied in the angle between the joining surface 125 and the centering surface 134 of the outer support element 123 of the piston upper part 11.
• the solder material can be applied as a circulating solder deposit 133 or in the form of a plurality of point or line-shaped solder deposits.
• a further dome-shaped solder deposit 135 filled with solder material is provided in the joining surface 128 of the central support member of the piston lower part 12.
• the upper piston part 11 and the lower piston part 12 are brought along their joining surfaces 124, 125 and 128, 129 into contact and assembled to form a piston body, wherein the centering surface 134 ensures the correct orientation of piston upper part 11 and piston lower part 12.
• the soldering method for manufacturing the pistons 10, 110 was performed as follows in this embodiment.
• the basic material chosen was AFM 38MnVS6 according to DIN-EN10267 and material number 1.1303.
• As a high-temperature solder material the nickel-based solder L-BNi2 according to EN 1044 and DIN 8513 was selected.
• the target composition of this solder material is 7 wt .-% chromium, 3.1 wt .-% boron, 4.5 wt .-% silicon, 3 wt .-% iron and at most 0.06 wt .-% carbon and nickel to 100 % By weight (all percentages based on the solder material).
• the range of the melting temperature along the solidus-liquidus line in the melt diagram is 970 0 C to 1000 0 C.
• the range of the soldering temperature is 1010 ° C to 1180 ° C.
• the piston bodies were placed in a known high-temperature vacuum furnace with a cooling gas device.
• the vacuum oven was evacuated until a pressure of about 5x10 3 mbar was reached.
• the vacuum oven was heated to a soldering temperature of 1150 0 C.
• the pressure was at most 10 '2 mbar during the heating phase.
• the soldering temperature was min in the exemplary embodiment 15 to 60 held min constant, where the pressure is up to about 5x10 "4 mbar sank. Then, the vacuum oven was cooled (see FIG.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (7)

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• 2009
  • 2009-07-14 DE DE102009032941A patent/DE102009032941A1/de active Pending
• 2010
  • 2010-06-29 WO PCT/DE2010/000753 patent/WO2011006469A1/de active Application Filing
  • 2010-06-29 EP EP10742706A patent/EP2454464A1/de not_active Withdrawn
  • 2010-06-29 CN CN201080038350.7A patent/CN102483009B/zh active Active
  • 2010-06-29 US US13/383,682 patent/US8991046B2/en active Active
  • 2010-06-29 JP JP2012519881A patent/JP2012533020A/ja active Pending
  • 2010-06-29 KR KR1020127003624A patent/KR101649010B1/ko active IP Right Grant

Non-Patent Citations (2)

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