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 
  • F02F3/02—Pistons  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—Pistons 
  • F02F3/02—Pistons  having means for accommodating or controlling heat expansion
  • F02F3/022—Pistons  having means for accommodating or controlling heat expansion the pistons having an oval circumference or non-cylindrical shaped skirts, e.g. oval

Definitions

• the invention relates to a piston for a
• the preamble is formed by the piston of DE 10 2008 002 536 A1.
• Compression stroke and at the beginning of an expansion stroke ignited a fuel-air mixture and burned.
• Reciprocating engines this is done in a combustion chamber, which is limited to a crankcase by a piston that moves up and down in a cylinder.
• the piston is connected to a crankshaft via a connecting rod.
• a piston pin For coupling the piston with the connecting rod is in turn a piston pin, which is received in a piston formed in the piston pin hub.
• DE 10 2009 032 379 A1 discloses a piston with pressure side
• Box walls that are straight and oblique, that the distance between the box walls in the area of the pin bosses is greater than in the region of the pressure-side shaft wall. This should improve the shaft-box wall connection.
• EP 0 913 566 A2 describes a cooled piston for
• DE 40 19 968 C2 discloses a piston whose so-called piston skirt part at least partially has an elliptical shape on the outside.
• Box wall cracks in the area of the connection of the box wall to the piston skirt are caused by a bending moment, which occurs during the deformation of the piston skirt under ignition pressure and acts in the region of the transition piston skirt to the box wall.
• Conventional methods, in particular the attempt of a more or less large transition radius between box wall and side wall, have not been able to solve this problem satisfactorily.
• the invention is based on the object to provide a piston with reduced formation of box-wall cracks in the region of the connection of the piston skirt to the box wall.
• a piston for use in internal combustion engines, wherein the piston has a shaft walls and
• Pressure side of the piston is provided in the installed state, and which is characterized in that in a region of this skirt wall, the recess is substantially limited in the form of a parabola, an elliptical section or a catenoid, said parabola, this elliptical section or these catenoids lie in a plane in the
• the shape of the Katenoide so the form, a free-hanging chain or a free-hanging rope under
• the axis of symmetry of the catenoids or the parabola or the major axis of the ellipse preferably lies along a straight line which extends from the associated skirt wall, preferably its center along the circumferential extent.
• the vertex of the catenoid or parabola, or one of the major vertexes of the ellipse is located at the respective associated stem wall, and preferably at the center thereof
• the axis of symmetry or the main axis runs between the two box walls. Their direction is preferably substantially parallel to the box walls and / or perpendicular to a straight line through the centers of any piston hubs.
• the minor axis preferably extends between the box walls and in an area between one
• Box walls, and the major axis of the ellipse corresponds substantially to half the diameter of the piston.
• the minor axis of the ellipse preferably runs parallel to the pin axis, that is to say the connecting line between the center points of the piston hubs.
• the box walls are the contrast recessed parts of the outer circumference of the piston.
• Support line is not interrupted.
• the piston is thus characterized by a further increased strength.
• a further preferred embodiment is that all pin bosses have a design as described above. This has the advantage that now both sides of the piston behave symmetrically and therefore the load from both sides is approximately the same, which manifests itself in a reduced wear.
• a further preferred embodiment is that the skirt wall on the pressure side of the straight line, which is opposite to the apex line of the geometric figure of the recess on the outer wall, starting in
• a further preferred embodiment is that the skirt wall on the pressure side of the straight line, which is opposite to the crest line of the geometric figure closest to the outer wall, starting in both Circumferential directions has an increasing thickness. This has the advantage that now both sides of the skirt wall behave the same and thus stresses and wear of less trained side are avoided.
• the shaft walls at the transition to the box walls are thicker than these. This has the advantage that you can work to save material because the shaft walls are the parts of the piston that are exposed to heavy loads while the box walls
• a piston is preferred in which the thickness of one, preferably all, of the box walls increases as one moves away from the line which lies on the recess surface and the
• Middle axis of the piston is the closest, moved to the shaft walls. This has the advantage that thereby the transition to the shaft walls can be made more continuous because thus a transition between walls with very different thicknesses can be avoided.
• Fig. 1 is a view of a piston according to the invention in the bottom view.
• the piston 10 shown therein has piston bosses 18 formed in a piston skirt 24 for receiving a piston pin (not shown).
• the piston skirt 24 includes two skirt walls 12, 14 and two box walls 16 which enclose a recess 20. In the installed state of the piston pin (not shown) passes through the piston bosses 18 which are formed in the box walls 16, and the
• the skirt walls 12, 14 are formed differently, depending on whether they are intended for use on the pressure side DS or the counterpressure side GDS.
• the inside 22 of the skirt wall 12 on the pressure side is pronounced as a parabola, this parabola protruding from the edge of the skirt Shaft wall is formed continuously to the piston crown, while the inside of the skirt wall 14 is not formed on the counter-pressure side in this way.
• this parabola lies so that its vertex lies along the circumferential direction in the middle of the associated skirt wall 14.
• the axis of symmetry of the parabola extends perpendicular to the connecting line between the centers of the piston bosses 18.
• box walls 16 are “inside" to the
• Pin bosses 18 i. they extend over the outer surface of the piston as seen from the central axis of the piston
• the skirt walls 12, 14 are wider at their intersection with the box walls 16, and the interface is further characterized by a transition between the box wall and the skirt wall, at which the outer surface at the transition has an outward projection ,
• the advantage stems from the fact that the Shaft wall substantially the shape of the piston follows while the box wall at least at the interfaces between the box wall and shaft wall approximately perpendicular to this
• skirt wall 12, 14 becomes thicker as one moves away from the straight line which, in the case of the pressure side, the vertex of the geometric figure or, in the case of the back pressure side, the diametrically opposite line GDS.

Landscapes

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

Applications Claiming Priority (2)

Publications (1)

Family

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Family Applications (1)

Country Status (9)

Families Citing this family (7)

Citations (1)

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• 2011
  • 2011-01-13 DE DE102011002653A patent/DE102011002653A1/de not_active Ceased
• 2012
  • 2012-01-11 JP JP2013548822A patent/JP2014507588A/ja active Pending
  • 2012-01-11 US US13/979,692 patent/US8955488B2/en active Active
  • 2012-01-11 WO PCT/EP2012/050347 patent/WO2012095445A1/de active Application Filing
  • 2012-01-11 EP EP12700127.9A patent/EP2663760A1/de not_active Withdrawn
  • 2012-01-11 KR KR1020137020548A patent/KR20140016887A/ko not_active Application Discontinuation
  • 2012-01-11 BR BR112013017725A patent/BR112013017725A2/pt not_active Application Discontinuation
  • 2012-01-11 CN CN201280005441XA patent/CN103443432A/zh active Pending
  • 2012-01-11 MX MX2013008004A patent/MX2013008004A/es active IP Right Grant

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Non-Patent Citations (1)

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