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 
  • F02F3/16—Pistons  having cooling means
  • F02F3/20—Pistons  having cooling means the means being a fluid flowing through or along piston
• • 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
• • 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
  • F02F2003/0053—Multi-part pistons the parts being connected by casting, brazing, welding or clamping by soldering
• • 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

Definitions

• the present invention relates to a piston for an internal combustion engine, with a piston lower part and a piston upper part arranged on the piston lower part, which has a peripheral around its circumference of the top land and a circumferential ring around its circumference.
• a known from DE 103 40 292 A1 piston consists of a substantially cylindrical base body having a ring member in the radially outer region of the piston head, which forms a cooling channel with the base body.
• the ring element receives a ring carrier for a compression ring.
• the solution consists in a piston with the features of claim 1 and a method having the features of claim 14.
• at least the upper piston part consists of a sintered material.
• the method according to the invention is characterized in that at least the piston upper part is produced by pressing and sintering, that the piston lower part is produced by pressing and sintering or casting or forming and that the piston lower part and the piston upper part are joined together by means of a solder material.
• the design of at least the Koi As a sintered component it is possible to design the structures and properties of the piston according to the invention, such as, for example, weight, overall height, cooling, etc., much more variably than hitherto.
• powdered sintered materials can be used with arbitrary selectable composition, which are pressed into a molded part and then sintered to the finished upper piston part or to finished upper piston parts and lower piston parts.
• extremely diverse microstructures can be realized in a particularly simple manner, for example from ferritic to austenitic states and mixtures thereof (duplex).
• the inventive method is also characterized by special economy.
• the piston lower part is made of a forged or cast material, in particular a steel material, while the piston upper part is preferably made of a sintered steel material.
• a forged or cast material in particular a steel material
• the piston upper part is preferably made of a sintered steel material.
• Such materials are characterized by a particularly high thermal resistance, which is particularly advantageous when used in diesel engines.
• the sintered material of the upper piston part and possibly a sintered lower piston part may be infiltrated with a metallic material to increase its thermal conductivity. This improves the heat dissipation from the piston and lowers the component temperature.
• a particularly preferred embodiment provides that the piston lower part and the piston upper part are connected to each other by means of a Lotwerkstoffes.
• the solder material penetrates by capillary action both in the interstices between the piston lower part and the piston upper part and in the pores at least of the sintered piston upper part.
• solder materials are, for example, copper, copper alloys, nickel or nickel alloys.
• inner and outer, corresponding to one another are preferably de joint surfaces provided, wherein the solder material is expediently provided in the region of the joining surfaces.
• the sintered material used in the individual case can be infiltrated with the solder material.
• the sintering of the sintered material and the joining of the piston lower part and piston upper part can take place in a single production step.
• a metallic material for infiltrating the sintered material whose melting temperature is lower than the melting temperature of Lotderstoffs to a reliable and complete infiltration of the sintered material sure.
• the infiltration of the sintered material and the joining of piston upper part and lower piston part then take place during the heating at different temperature levels.
• the piston head can be provided in a manner known per se with a combustion bowl of arbitrary design depending on the engine design. Depending on the requirements of the individual case, this combustion bowl can be formed either only from the piston upper part or both from the piston upper part and from the piston lower part.
• the piston upper part and the piston lower part may include an outer circumferential cooling channel.
• an inner cooling space or an inner circumferential cooling channel can be provided. The heat dissipation then takes place from the piston, in particular from the piston crown area in the direction of the cooling channel or the cooling channels.
• Fig. 2 shows another Ausf ⁇ hrungsbeispiel of a piston according to the invention in section.
• FIG. 1 shows a first exemplary embodiment of a piston 10 according to the invention.
• the piston 10 has a piston lower part 11, which in the exemplary embodiment is made of a forged or cast metallic material.
• forged steels such as AFP steels, for example 38MnVS6 or tempered steels such as, for example, 42CrMo4, are suitable.
• the piston 10 further has a piston upper part 12, which is made of a sintered material, in particular a sintered steel material.
• alloys of iron and carbon or alloys of iron, carbon and molybdenum are suitable. In particular, ferritic microstructures can be achieved with these alloys.
• the carbon content is preferably 0.4-0.8%
• the molybdenum content is preferably 0.0-2.0%, especially 0.8-1.6%.
• the lower piston part 11 has a piston shaft 20 and the central or inner region 13 of a piston crown 14, which is provided in a manner known per se with a combustion bowl 15. Beneath the piston head 14 are provided hubs 16, which are provided with hub bores 17 for the passage of a piston pin (not shown).
• the piston upper part 12 has a circumferential, substantially cylindrical ring element 24, which is provided in a conventional manner on its lateral surface with a top land 25 and a ring portion 26 with a plurality of annular grooves for receiving piston rings, not shown.
• the lower free end of the ring element 24 forms an outer joining surface 27, which is supported on a corresponding joining surface 28 of the piston lower part 11.
• the ring member 24 further includes a radially inwardly extending peripheral edge 29 which defines the outer annular portion of the piston crown 14 forms.
• the lower free end of the edge 29 forms an inner joining surface 31, which is supported on a corresponding joining surface 32 of the piston lower part 11.
• the piston lower part 11 and the piston upper part 12 are joined together by means of a brazing material which is provided along the joining surfaces 27, 28 and 31, 32.
• a brazing material which is provided along the joining surfaces 27, 28 and 31, 32.
• copper or copper alloys or nickel or nickel alloys are suitable.
• the melting point of the solder material is lower than the melting point of the material of the piston lower part 11 and lower than the melting point of the material of the piston upper part 12.
• the melting point of the solder material is also higher than the maximum operating temperature occurring at the piston 10.
• the ring element 24 and the peripheral edge 29 of the piston upper part 12 or a circumferential recess 33 introduced into the piston lower part 11 form an outer circumferential cooling channel 34.
• FIG. 2 shows a further exemplary embodiment of a piston 110 according to the invention.
• the piston 110 has a piston lower part 111 which, in the exemplary embodiment, consists of the same material as the piston lower part 11 of the piston 10 from FIG. 1.
• the piston 110 also has a piston upper part 112, which in the FIG Embodiment also consists of the same material as the upper piston part 12 of the piston 10 of Figure 1.
• the lower piston part 111 further also has a piston shaft 120 and provided with hub bores 117 hubs 116 on.
• the piston upper part 112 has a piston bottom 114, which is provided in a manner known per se with a combustion bowl 115.
• the combustion bowl 115 is formed alone in the piston upper part 112 in this embodiment.
• the piston head 114 is bounded by a circumferential, substantially cylindrical ring element 124.
• the ring member 124 is provided in a conventional manner on its lateral surface with a top land 125 and a ring portion 126 with a plurality of annular grooves for receiving piston rings, not shown.
• the lower free end of the ring element 124 forms a joining surface 127, which is supported on a corresponding joining surface 128 of the piston lower part 111.
• the piston upper part 112 has two further joining surfaces below the combustion bowl 115.
• an inner peripheral joining surface 131 is provided, which is supported on a corresponding inner circumferential joining surface 132 of the piston lower part 11. Furthermore, a central joining surface 135 is provided, which is supported on a corresponding joining surface 136 of the piston lower part 111.
• the piston lower part 111 and the piston upper part 112 are joined together by means of a brazing material which is provided along the joining surfaces 127, 128 or 131, 132 and 135, 136.
• a brazing material which is provided along the joining surfaces 127, 128 or 131, 132 and 135, 136.
• copper or copper alloys or nickel or nickel alloys are suitable.
• the melting point of the solder material is lower than the melting point of the material of the piston lower part 111 and lower than the melting point of the material of the piston upper part 112.
• the melting point of the solder material is also higher than the maximum operating temperature occurring at the piston 110.
• a circumferential recess 133a provided in the piston upper part 112 between the ring element 124 and the combustion bowl 115 or a corresponding circumferential recess 133b provided in the piston lower part 111 form an outer circumferential cooling passage 134.
• an inner circumferential cooling channel 137 is formed between the inner circumferential joining surfaces 131, 132 and the central joining surfaces 135, 136 Furthermore, an inner circumferential cooling channel 137 is formed. If the joining surfaces 135, 136 are dispensed with, instead of the inner circumferential cooling channel, a central cooling space is created (not shown).
• the piston lower part 11, 111 and the piston upper part 12, 112 are joined together by means of the solder material in a conventional manner.
• the solder material is brought into contact with the joining surfaces and heated together with the piston lower part 11, 111 and the piston upper part 12, 112 until the solder material melts. Due to the capillary effect, the solder material penetrates both into the intermediate spaces between the joining surfaces and into the pores of the sintered material of the upper piston part 12, 112 or the sintered materials of both parts of the piston 10, 110. In this case, it is expedient to sinter at least the upper piston part 12, 112 and the upper part of the piston.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (8)

Families Citing this family (37)

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• 2007
  • 2007-12-20 DE DE102007061601A patent/DE102007061601A1/de not_active Withdrawn
• 2008
  • 2008-12-08 US US12/315,968 patent/US8074617B2/en not_active Expired - Fee Related
  • 2008-12-10 CN CN2008801221521A patent/CN101903633A/zh active Pending
  • 2008-12-10 BR BRPI0821785-8A patent/BRPI0821785A2/pt not_active IP Right Cessation
  • 2008-12-10 KR KR1020107015757A patent/KR101510916B1/ko not_active IP Right Cessation
  • 2008-12-10 WO PCT/DE2008/002073 patent/WO2009079988A1/de active Application Filing
  • 2008-12-10 EP EP08864437A patent/EP2229522A1/de not_active Withdrawn
  • 2008-12-10 JP JP2010538330A patent/JP5502748B2/ja not_active Expired - Fee Related
• 2011
  • 2011-10-11 US US13/270,324 patent/US8950375B2/en not_active Expired - Fee Related
• 2015
  • 2015-02-09 US US14/617,470 patent/US20150152807A1/en not_active Abandoned

Non-Patent Citations (1)

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