EP0356457B1 - Light-metal trunk piston for internal combustion engines - Google Patents

Light-metal trunk piston for internal combustion engines Download PDF

Info

Publication number
EP0356457B1
EP0356457B1 EP88903796A EP88903796A EP0356457B1 EP 0356457 B1 EP0356457 B1 EP 0356457B1 EP 88903796 A EP88903796 A EP 88903796A EP 88903796 A EP88903796 A EP 88903796A EP 0356457 B1 EP0356457 B1 EP 0356457B1
Authority
EP
European Patent Office
Prior art keywords
piston
skirt
pressure side
counter
light
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.)
Expired - Lifetime
Application number
EP88903796A
Other languages
German (de)
French (fr)
Other versions
EP0356457A1 (en
Inventor
Hugo Gabele
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.)
Mahle GmbH
Original Assignee
Mahle GmbH
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Mahle GmbH filed Critical Mahle GmbH
Publication of EP0356457A1 publication Critical patent/EP0356457A1/en
Application granted granted Critical
Publication of EP0356457B1 publication Critical patent/EP0356457B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

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 
    • F02F3/02—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
    • 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
    • F02F3/04—Pistons  having means for accommodating or controlling heat expansion having expansion-controlling inserts
    • F02F3/042—Pistons  having means for accommodating or controlling heat expansion having expansion-controlling inserts the inserts consisting of reinforcements in the skirt interconnecting separate wall parts, e.g. rods or strips
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/02—Light metals
    • F05C2201/021—Aluminium
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05C—INDEXING SCHEME RELATING TO MATERIALS, MATERIAL PROPERTIES OR MATERIAL CHARACTERISTICS FOR MACHINES, ENGINES OR PUMPS OTHER THAN NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES
    • F05C2201/00—Metals
    • F05C2201/04—Heavy metals
    • F05C2201/0433—Iron group; Ferrous alloys, e.g. steel
    • F05C2201/0448—Steel

Definitions

  • the invention relates to a light metal plunger for internal combustion engines according to the same preamble of the two independent claims 1 and 2.
  • Such pistons are known from GB-PS 12 56 242.
  • a control strip is used at the upper end of the shaft, which has a width that varies over its circumference. The width varies in such a way that the radial thickness of the control strip is the smallest on the pressure side of the piston and the greatest on the counterpressure side. This results in a smaller radial expansion of the upper shaft area on the counter pressure side of the shaft than on the pressure side. Due to the smaller expansion of the upper shaft area on the counter pressure side under temperature, a tight running play of the shaft can be achieved in the cold state. The tighter running play is associated with a reduction in the running noise in the cold state, which is strongly influenced by a striking of the top land on the counter-pressure side against the cylinder liner in the cold state of the engine.
  • the object of the invention is to further reduce the noise generation in the generic piston which is caused by the piston head striking against the cylinder liner on the counterpressure side when the piston is cold.
  • the piston assumes in the cold state in the engine cylinder a position in which the piston head is inclined with its upper end on the pressure side relative to the cylinder running surface in such a way that there is play in the top land area relative to the cylinder running surface on the counter pressure side is larger than on the pressure side.
  • the specified inclination of the piston head in the cold state of the piston in the engine cylinder is achieved in that the counter-pressure side surface of is inclined upwards downwards with respect to the piston longitudinal axis, specifically with the radial distance decreasing towards the lower piston end towards the piston axis.
  • the abutment of the piston on the lateral surface so inclined on the counter-pressure side is further favored by the inclination of the shaft lateral surface there, given in the opposite direction on the pressure side. This statement in turn relates to the cold state.
  • Advantageous for achieving the inclined position of the piston desired in partial engine load operation is the substantially straight line surface profile over a wide range on the counter pressure side.
  • the control strip inserted on the counter-pressure side in the upper end area of the skirt causes a hindrance to the thermal expansion of the light metal in this area of the skirt, while the lower area of the stem on the counter-pressure side can expand considerably more freely without a control strip.
  • the surface line on the counterpressure side of the shaft receives a course in full-load operation of the engine, which is aligned essentially parallel to the longitudinal axis of the piston head.
  • the piston head then also runs centrally in the cylinder bore.
  • the control strip provided on the pressure side in the lower shaft area exerts an influence in the same direction. This ensures that by a greater radial distance the skirt lateral surface in the control strip area to the longitudinal axis of the piston compared to the overlying shaft area on the counterpressure side, a system in the lower shaft area is additionally favored.
  • a common measure to reduce piston noise when the engine is running is to debach the piston hub bore.
  • This roofing is usually on the print side. This creates a tilting moment at the top dead center of the compression stroke when combustion starts, which pushes the piston head in the direction of the counter pressure side.
  • the lower stem area of the piston on the counter pressure side is pressed radially outwards. This creates contact forces in the aforementioned shaft areas (counter pressure side above or pressure side bottom) which are to be absorbed with the smallest possible elastic deformation.
  • the piston skirt In the upper area of the stem, the piston skirt should be on the.
  • the counter-pressure side on the other hand, must be relatively stiff in order to ensure the greater radial distance between the lateral surface and the longitudinal axis of the piston head in the cold state compared to the lower region and not to restrict it again in this region due to excessive elastic deformability.
  • the different stiffnesses can be determined by the size of the unsupported arch length of the shaft vary on the pressure and counter pressure side.
  • these measures consist in particular in the provision of a transverse slot between the piston head and the piston skirt on the counter-pressure side and in the provision of a control strip in the upper region of the piston skirt exclusively on the counter-pressure side and, if appropriate, an additional control strip in the lower region of the pressure-side stem half.
  • Unsymmetrical shaft shapes are also known per se from DE 35 27 032 A1, but there are also no references to the specific he inventive design of the shaft to reduce the impact noise of the piston head.
  • the piston is made of an aluminum-silicon alloy.
  • ring grooves 1 for Kom compression rings and an underlying groove 2 provided for an oil control ring.
  • the stem of the piston is separated from the piston head on the counterpressure side by a transverse slot 3.
  • the transverse slot 3 extends in the circumferential direction over a total of 90 degrees, namely symmetrically on both sides of the plane running through the longitudinal axis X in the pressure-counter pressure direction.
  • a control strip 4 made of steel is used exclusively on the counter-pressure side in the interior of the shaft in the upper region thereof.
  • the control effect emanating from this control strip when the piston warms up is measured to a maximum of about 50 my with piston diameters between 70 and 100 mm.
  • Fig. 4 the position of the piston according to Fig. 1 is drawn, which it assumes in the cold state in the engine cylinder during the compression stroke. Due to the conrod angle during this stroke, the piston rests with its shaft on the counter pressure side during the downward movement. Alignment takes place in the area of the piston skirt on the counterpressure side through the axial surface line existing there in a straight line over a larger area.
  • the straight generatrix extends there from the lower end of the shaft to about 15% before the upper end of the shaft.
  • the axial generatrix is essentially spherical.
  • the decisive noise reduction lies in the fact that the circumference of the piston head on the counter-pressure side is sufficiently distant from the cylinder running surface due to the shaft jacket which is inclined there. so as not to hit the cylinder wall under partial load or when the engine is not yet warm.
  • the inclination of the axial surface line of the shaft on the counter-pressure side is chosen to such an extent that, in full-load operation, the control effect of the control strip 4 results in a parallel profile of this surface line to the longitudinal axis X.
  • the control strip 4 is attached directly to the upper end of the shaft and in the example shown extends over a height of 25% of the total shaft length.
  • the diameter of the top land of the piston head is less than the maximum diameter of the piston skirt.
  • Fig. 4 shows quite clearly how the piston head is brought into such an inclined position by the shaft when the piston is cold, that the play between the ring portion and the cylinder running surface on the counterpressure side of the piston is significantly greater than on the diametrically opposite pressure side of the piston. This prevents the ring part from striking the piston, which causes the piston noise.
  • control strips 4 and 5 each extend Weil of one of the two hubs 6 areas circumferentially up to the piston tilt plane running perpendicular to the piston pin axis, ie the control strips are circumferentially separated from one another in the area of the piston tilt plane.
  • control strips 4 and 5 are connected to a common control strip 7 connected in the region of the piston hub 6.
  • the piston can be installed in this lower shaft area in the cold state with a radial play so narrow there that on the counter-pressure side an attachment to the shaft jacket inclined from top to bottom is promoted.
  • the piston tilts to the counter pressure side, it comes into contact with the underside of the shaft on the pressure side earlier, which reduces the tilt angle.
  • the stiffness of the piston shaft is changed over the axial height in that the load-bearing shaft surfaces are unequal in circumference and are supported radially inwards at the circumferential end.
  • the different elasticity in the axial direction is distributed in such a way that the piston skirt on the counter pressure side in the upper area, in which the control strip 4 is located, is stiffer than in the skirt area below.
  • the lower shaft area is made stiffer than the lower shaft area opposite on the counter pressure side.
  • the course of the walls 10 connecting the supporting shaft surfaces 8, 9 in the direction of the piston axis is predetermined by the shape of the bearing surfaces 8, 9 which change over the height of the shaft.
  • the hubs 6 can protrude radially beyond these walls 10.
  • a narrow circumferential collar 11 can be provided at the lower end of the shaft. Such a collar enables the piston to be transported in a rolling manner through the individual production stations.

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)

Abstract

The external profile of a piston rod employed in the engines of passenger cars ensures smoother piston travel on start-up and during partial loading. In these operating ranges, piston ring parts may impact on the sliding surface of the cylinder on the counter-pressure side and give rise, amongst others things, to undesirable noise. To obviate such impacts, the piston rod tapers at the end facing the crankshaft space on the counter-pressure side, and has a transversal slit (3) at its junction with the piston head and an adjustment strip (4) in the vicinity of the said slit. An additional adjustable strip (5) may also be provided in the lower part of the rod, on the pressure side. As a result of the position of the adjustment strips, the special design of the piston and the special shape of the rod casing, the piston head aligns itself at a slight angle to the counter-pressure side, with increasing play between the piston head and the sliding surface of the cylinder, in the said operating ranges. When the engine is running at full load, the piston head realigns itself in the direction of its axis.

Description

Leichtmetall-Tauchkolben für VerbrennungsmotorenLight metal plunger for internal combustion engines

Die Erfindung betrifft einen Leichtmetall-Tauchkolben für Verbrennungsmotoren nach dem jeweils gleichen Oberbegriff der beiden unabhängigen Patentansprüche 1 und 2.The invention relates to a light metal plunger for internal combustion engines according to the same preamble of the two independent claims 1 and 2.

Derartige Kolben sind aus GB-PS 12 56 242 bekannt. Bei jenem bekannten Kolben ist am oberen Schaftende ein Regelstreifen eingesetzt, der eine über seinen Umfang variierende Breite aufweist. Dabei variiert die Breite in der Weise, daß die radiale Dicke des Regelstreifens auf der Druckseite des Kolbens am ge­ringsten und auf der Gegendruckseite am größten ist. Dadurch erfolgt auf der Gegendruckseite des Schaftes eine geringere radiale Ausdehnung des oberen Schaft­bereiches als auf der Druckseite. Durch die geringere Ausdehnung des oberen Schaftbereiches auf der Gegen­druckseite unter Temperatur ist ein enges Laufspiel des Schaftes im Kaltzustand erreichbar. Mit dem enge­ren Laufspiel verbunden ist eine Verminderung des Laufgeräusches im Kaltzustand, das durch ein Anschla­gen des Feuersteges auf der Gegendruckseite an die Zylinderlaufbahn im Kaltzustand des Motors stark beeinflußt ist.Such pistons are known from GB-PS 12 56 242. In that known piston, a control strip is used at the upper end of the shaft, which has a width that varies over its circumference. The width varies in such a way that the radial thickness of the control strip is the smallest on the pressure side of the piston and the greatest on the counterpressure side. This results in a smaller radial expansion of the upper shaft area on the counter pressure side of the shaft than on the pressure side. Due to the smaller expansion of the upper shaft area on the counter pressure side under temperature, a tight running play of the shaft can be achieved in the cold state. The tighter running play is associated with a reduction in the running noise in the cold state, which is strongly influenced by a striking of the top land on the counter-pressure side against the cylinder liner in the cold state of the engine.

Hiervon ausgehend liegt der Erfindung die Aufgabe zu­grunde, bei dem gattungsgemäßen Kolben die Geräusch­bildung, die durch das Anschlagen des Kolbenkopfes im Kaltzustand des Kolbens auf der Gegendruckseite gegen die Zylinderlaufbahn verusacht wird, noch weiter zu vermindern.Proceeding from this, the object of the invention is to further reduce the noise generation in the generic piston which is caused by the piston head striking against the cylinder liner on the counterpressure side when the piston is cold.

Gelöst wird diese Aufgabe bei dem gattungsgemäßen Kolben durch eine Ausbildung des Kolbenschaftes nach den kennzeichnenden Merkmalen des Patentanspruchs 1 oder 2.This object is achieved in the generic piston by designing the piston skirt according to the characterizing features of patent claim 1 or 2.

Zweckmäßige Ausgestaltungen der Erfindung sind Gegenstand der Unteransprüche.Appropriate embodiments of the invention are the subject of the dependent claims.

Durch den Aufbau und die Außenform des Kolbenschaftes nach Anspruch 1 nimmt der Kolben in kaltem Zustand in dem Motorzylinder eine Lage an, in der der Kolbenkopf mit seinem oberen Ende auf der Druckseite gegenüber der Zylinderlauffläche so geneigt ist, daß im Feuer­stegbereich das Spiel gegenüber der Zylinderlaufflä­che auf der Gegendruckseite größer ist als auf der Druckseite. Dadurch wird bei Motoranlauf und im Teil­lastbetrieb, in dem der Kolben noch relativ geringe Temperaturen aufweist, eine Geräuschbildung durch An­schlagen der Ringpartie auf der Gegendruckseite vermieden.Due to the structure and the outer shape of the piston skirt according to claim 1, the piston assumes in the cold state in the engine cylinder a position in which the piston head is inclined with its upper end on the pressure side relative to the cylinder running surface in such a way that there is play in the top land area relative to the cylinder running surface on the counter pressure side is larger than on the pressure side. As a result, when starting the engine and in partial load operation, in which the piston is still at relatively low temperatures, noise is avoided by striking the ring section on the counter-pressure side.

Die angegebene Neigung des Kolbenkopfes im Kaltzu­stand des Kolbens im Motorzylinder wird dadurch er­reicht, daß die gegendruckseitige Mantelfläche von oben nach unten gegenüber der Kolbenlängsachse ge­neigt ist und zwar mit zum unteren Kolbenschaftende hin gegenüber der Kolbenachse abnehemendem radialen Abstand. Die Anlage des Kolbens an die auf der Gegen­druckseite so geneigte Mantelfläche wird noch begün­stigt durch die nach Anspruch 2 auf der Druckseite in umgekehrter Richtung gegebene Neigung der dortigen Schaftmantelfläche. Diese Aussage bezieht sich wie­derum auf den Kaltzustand.The specified inclination of the piston head in the cold state of the piston in the engine cylinder is achieved in that the counter-pressure side surface of is inclined upwards downwards with respect to the piston longitudinal axis, specifically with the radial distance decreasing towards the lower piston end towards the piston axis. The abutment of the piston on the lateral surface so inclined on the counter-pressure side is further favored by the inclination of the shaft lateral surface there, given in the opposite direction on the pressure side. This statement in turn relates to the cold state.

Vorteilhaft für die Erzielung für die im Motorteil- lastbetrieb gewünschte geneigte Lage des Kolbens ist der auf der Gegendruckseite über einen weiten Bereich in wesentlichen geradlinige Mantellinienverlauf.Advantageous for achieving the inclined position of the piston desired in partial engine load operation is the substantially straight line surface profile over a wide range on the counter pressure side.

Mit zunehmender Wärme des Kolbenschaftes bewirkt der auf der Gegendruckseite im oberen Endbereich des Schaftes eingelegte Regelstreifen eine Behinderung der Wärmeausdehnung des Leichtmetalles in diesem Schaftbereich, während der untere gegendruckseitige Bereich des Schaftes sich ohne Behinderung durch ei­nen Regelstreifen erheblich stärker ausdehnen kann. Dadurch erhält die Mantellinie auf der Gegendrucksei­te des Schaftes im Vollastbetrieb des Motors einen Verlauf, der im wesentlichen parallel zu der Kolben­kopflängsachse ausgerichtet ist. Damit läuft dann auch der Kolbenkopf zentrisch in der Zylinderbohrung.With increasing heat of the piston skirt, the control strip inserted on the counter-pressure side in the upper end area of the skirt causes a hindrance to the thermal expansion of the light metal in this area of the skirt, while the lower area of the stem on the counter-pressure side can expand considerably more freely without a control strip. As a result, the surface line on the counterpressure side of the shaft receives a course in full-load operation of the engine, which is aligned essentially parallel to the longitudinal axis of the piston head. The piston head then also runs centrally in the cylinder bore.

Einen in die gleiche Richtung wirksamen Einfluß übt der auf der Druckseite im unteren Schaftbereich vor­gesehene weitere Regelstreifen aus. Dieser sorgt näm­lich dafür, daß durch einen größeren radialen Abstand der Schaftmantelfläche im Regelstreifenbereich zur Kolbenlängsachse im Vergleich zu dem darüberliegenden Schaftbereich auf der Gegendruckseite eine Anlage im unteren Schaftbereich noch zusätzlich begünstigt wird.The control strip provided on the pressure side in the lower shaft area exerts an influence in the same direction. This ensures that by a greater radial distance the skirt lateral surface in the control strip area to the longitudinal axis of the piston compared to the overlying shaft area on the counterpressure side, a system in the lower shaft area is additionally favored.

Eine übliche Maßnahme zur Reduzierung von Kolbenge­räuschen im Motorlauf besteht in einer Desachsierung der Nabenbohrung des Kolbens. Diese Desachsierung liegt in der Regel zur Druckseite. Dadurch entsteht im oberen Totpunkt des Verdichtungshubes bei einset­zender Verbrennung ein Kippmoment, das den Kolbenkopf in Richtung Gegendruckseite drückt. Gleichzeitig wird der untere Schaftbereich des Kolbens auf der Gegen­druckseite nach radial außen gedrückt. Es entstehen also in den vorgenannten Schaftbereichen (Gegendruck­seite oben bzw. Druckseite unten) Anlagekräfte, die bei möglichst kleiner elastischer Verformung aufge­nommen werden sollen. Für eine enge Führung des im Kaltzustand gegen die Kolbenkopflängsachse geneigten Schaftes ist es daher vorteilhaft, den Schaft im un­teren Bereich auf der Druckseite steifer als auf der Gegendruckseite auszubilden. Im oberen Schaftbereich soll der Kolbenschaft auf der. Gegendruckseite dagegen wiederum relativ steif sein, um dort den im Kaltzu­stand gegenüber dem unteren Bereich größeren Radial­abstand der Mantelfläche zur Kolbenkopflängsachse si­cherzustellen und nicht durch eine zu hohe elasti­sche Verformbarkeit in diesem Bereich wieder einzu­schränken. Die unterschiedlichen Steifigkeiten lassen sich u.a. durch die Größe der ungestützten Bogenlänge des Schaftes auf Druck- und Gegendruckseite variieren.A common measure to reduce piston noise when the engine is running is to debach the piston hub bore. This roofing is usually on the print side. This creates a tilting moment at the top dead center of the compression stroke when combustion starts, which pushes the piston head in the direction of the counter pressure side. At the same time, the lower stem area of the piston on the counter pressure side is pressed radially outwards. This creates contact forces in the aforementioned shaft areas (counter pressure side above or pressure side bottom) which are to be absorbed with the smallest possible elastic deformation. For tight guidance of the stem, which is inclined against the longitudinal axis of the piston head in the cold state, it is therefore advantageous to make the stem stiffer in the lower region on the pressure side than on the counterpressure side. In the upper area of the stem, the piston skirt should be on the. The counter-pressure side, on the other hand, must be relatively stiff in order to ensure the greater radial distance between the lateral surface and the longitudinal axis of the piston head in the cold state compared to the lower region and not to restrict it again in this region due to excessive elastic deformability. The different stiffnesses can be determined by the size of the unsupported arch length of the shaft vary on the pressure and counter pressure side.

Geräuschprobleme bestehen bei Warmbetrieb des Motors in der Regel nicht. Dies liegt daran, daß sich das Laufspiel bei warmem Kolben soweit gegenüber dem zu­nächst vorhandenen Kaltspiel erniedrigt hat, daß ein Kolbenkippen, das zu einem Anschlagen des Feuersteges an die Zylinderwand führen kann, praktisch nicht mehr auftritt. Die Erniedrigung des Spieles im warmen Be­triebszustand kann zu einer theoretischen Überdeckung gegenüber der Zylinderlauffläche führen.There are generally no noise problems when the engine is warm. This is due to the fact that the running clearance with a warm piston has decreased so far compared to the cold clearance initially present that piston tilting, which can lead to the top land striking the cylinder wall, practically no longer occurs. The lowering of the play in the warm operating state can lead to a theoretical overlap with respect to the cylinder running surface.

Soweit aus JP-Abstract 57-81144 ein Kolben für Zwei­taktmotoren bekannt ist, bei dem zur Geräuschreduzie­rung der Schaft ein Profil aufweist, durch das teil­weise eine Kolbenschrägstellung bewirkt wird, fehlen dort die erfindungsgemäßen Maßnahmen zur geradlinigen Aufrichtung des Kolbens bei zunehmender Motorlast. Nach der Erfindung bestehen diese Maßnahmen insbeson­dere in dem Vorsehen eines Querschlitzes zwischen Kolbenkopf und Kolbenschaft auf der Gegendruckseite sowie in dem Vorsehen eines Regelstreifens in dem oberen Bereich des Kolbenschaftes ausschließlich auf der Gegendruckseite sowie ggf. zusätzlich noch eines weiteren Regelstreifens im unteren Bereich der druck­seitigen Schafthälfte.Insofar as a piston for two-stroke engines is known from JP Abstract 57-81144, in which the shaft has a profile to reduce noise, which partially causes the piston to be tilted, the measures according to the invention for rectilinear erection of the piston with increasing engine load are missing there. According to the invention, these measures consist in particular in the provision of a transverse slot between the piston head and the piston skirt on the counter-pressure side and in the provision of a control strip in the upper region of the piston skirt exclusively on the counter-pressure side and, if appropriate, an additional control strip in the lower region of the pressure-side stem half.

Unsymmetrische Schaftformen sind darüberhinaus an sich zwar ebenfalls aus DE 35 27 032 A1 bekannt, je­doch fehlen auch dort Hinweise auf die konkrete er­ findungsgemäße Ausgestaltung des Schaftes zur Redu­zierung der Aufschlaggeräusche des Kolbenkopfes.Unsymmetrical shaft shapes are also known per se from DE 35 27 032 A1, but there are also no references to the specific he inventive design of the shaft to reduce the impact noise of the piston head.

Ein Ausführungsbeispiel ist in der Zeichnung darge­stellt. Es zeigen

  • Fig. 1 eine erste Ausführung eines Kolbens im Längsschnitt
  • Fig. 2 den axialen Mantellinienverlauf des kalten und warmen Kolbenschaftes nach Fig. 1 auf der Gegendruckseite
  • Fig. 3 den axialen Mantellinienverlauf des kalten und warmen Kolbenschaftes nach Fig. 1 auf der Druckseite
  • Fig. 4 die schiefe Ausrichtung des kalten Kolbenschaftes nach Fig. 1 innerhalb des Motorenzylinders
  • Fig. 5 die Ausrichtung des warmen Kolbenschaftes nach Fig. 1 während des Motorbetriebes innerhalb des Motorenzylinders
  • Fig. 6 eine Ansicht des Kolbens nach Fig. 1 von unten
  • Fig. 7 den Polarmantellinienverlauf (kalter und warmer Zustand) des Kolbenschaftes in der Ebene VII
  • Fig. 8 den polaren Mantellinienverlauf (kalter und warmer Zustand) des Kolbenschaftes in Ebene VIII
  • Fig. 9 eine zweite Ausführung eines Kolbens im Längsschnitt
  • Fig. 10 den axialen Mantellinienverlauf des kalten und warmen Kolbenschaftes nach Fig. 9 auf der Gegendruckseite
  • Fig. 11 den axialen Mantellinienverlauf des kalten und warmen Kolbenschaftes nach Fig. 9 auf der Druckseite
  • Fig. 12 eine Ansicht des Kolbens nach Fig. 9 von unten
  • Fig. 13 einen Schnitt durch den Kolben in der Ebene XIII
  • Fig. 14 einen Schnitt durch den Kolben in der Ebene XIV
An embodiment is shown in the drawing. Show it
  • Fig. 1 shows a first embodiment of a piston in longitudinal section
  • Fig. 2 shows the axial generatrix of the cold and warm piston skirt according to Fig. 1 on the counter pressure side
  • Fig. 3 shows the axial generatrix of the cold and warm piston skirt according to Fig. 1 on the pressure side
  • Fig. 4 shows the oblique orientation of the cold piston skirt according to Fig. 1 within the engine cylinder
  • Fig. 5 shows the orientation of the warm piston skirt according to Fig. 1 during engine operation within the engine cylinder
  • Fig. 6 is a view of the piston of FIG. 1 from below
  • Fig. 7 shows the polar surface line course (cold and warm condition) of the piston skirt in level VII
  • Fig. 8 shows the polar surface line course (cold and warm condition) of the piston skirt in plane VIII
  • Fig. 9 shows a second embodiment of a piston in longitudinal section
  • Fig. 10 shows the axial generatrix of the cold and warm piston skirt according to Fig. 9 on the counter pressure side
  • Fig. 11 shows the axial generatrix of the cold and warm piston skirt according to Fig. 9 on the pressure side
  • Fig. 12 is a view of the piston of FIG. 9 from below
  • Fig. 13 shows a section through the piston in the plane XIII
  • Fig. 14 shows a section through the piston in the plane XIV

Der Kolben besteht aus einer Aluminium-Silizium-Le­gierung. In seinem Kopfteil sind Ringnuten 1 für Kom­ pressionsringe und eine darunterliegende Ringnut 2 für einen Ölabstreifring vorgesehen.The piston is made of an aluminum-silicon alloy. In its head part are ring grooves 1 for Kom compression rings and an underlying groove 2 provided for an oil control ring.

Die in der Zeichnung eingetragenen Buchstaben haben folgende Bedeutung:

  • D = maximaler Durchmesser des Kolbens
  • L = maximale Länge des Kolbens
  • H = Kompressionshöhe
  • A = mittlere Schafthöhe unterhalb der untersten Ringnut in einem Umfangsbereich etwa gleicher Schafthöhe von mindestens 90 Grad von jeweils der Druck- und Gegendruckseite
  • DS = Druckseite des Kolbens
  • GDS = Gegendruckseite des Kolbens
  • X = durch den Kolbenkopf bestimmte Längsachse des Kolbens
The letters in the drawing have the following meaning:
  • D = maximum diameter of the piston
  • L = maximum length of the piston
  • H = compression height
  • A = average shaft height below the lowest ring groove in a circumferential area of approximately the same shaft height of at least 90 degrees from the pressure and counter pressure side
  • DS = pressure side of the piston
  • GDS = counter pressure side of the piston
  • X = longitudinal axis of the piston determined by the piston head

Der Schaft des Kolbens ist auf der Gegendruckseite durch einen Querschlitz 3 von dem Kolbenkopf ge­trennt. Der Querschlitz 3 erstreckt sich in Umfangs­richtung über insgesamt 90 Grad und zwar symmetrisch zu beiden Seiten der durch die Längsachse X in Druck­Gegendruckrichtung verlaufende Ebene.The stem of the piston is separated from the piston head on the counterpressure side by a transverse slot 3. The transverse slot 3 extends in the circumferential direction over a total of 90 degrees, namely symmetrically on both sides of the plane running through the longitudinal axis X in the pressure-counter pressure direction.

Bei der Kolbenausführung nach Fig. 1 ist ausschließ­lich auf der Gegendruckseite im Inneren des Schaftes in dessen oberen Bereich ein Regelstreifen 4 aus Stahl eingesetzt. Der von diesem Regelstreifen bei sich erwärmendem Kolben ausgehende Regeleffekt bemißt sich auf im Maximum etwa 50 my bei Kolbendurchmessern zwischen 70 und 100 mm.1, a control strip 4 made of steel is used exclusively on the counter-pressure side in the interior of the shaft in the upper region thereof. The control effect emanating from this control strip when the piston warms up is measured to a maximum of about 50 my with piston diameters between 70 and 100 mm.

In Fig. 4 ist die Lage des Kolbens nach Fig. 1 einge­zeichnet, die dieser in kaltem Zustand in dem Motor­zylinder beim Verdichtungshub einnimmt. Durch die Pleuelschrägstellung während dieses Hubes liegt der Kolben mit seinem Schaft bei der Abwärtsbewegung auf der Gegendruckseite an. Die Ausrichtung erfolgt in dem Bereich des Kolbenschaftes auf der Gegendrucksei­te durch die dort vorhandene über einen größeren Be­reich geradlinig verlaufende axiale Mantellinie. Der geradlinige Mantellinienverlauf reicht dort von dem unteren Schaftende bis etwa 15% vor dem oberen Schaf­tende. Auf der Druckseite ist der axiale Mantelli­nienverlauf dagegen im wesentlichen ballig. Beim Zu­rückkippen des Kolbens von der Gegendruckseite zur Druckseite in der oberen Totpunktlage des Kolbens kann der Kolben auf der druckseitigen balligen Schaftform weich abrollen. Dadurch wird eine zusätz­liche Verbesserung des Kolbenschaftlaufgeräusches er­reicht.In Fig. 4 the position of the piston according to Fig. 1 is drawn, which it assumes in the cold state in the engine cylinder during the compression stroke. Due to the conrod angle during this stroke, the piston rests with its shaft on the counter pressure side during the downward movement. Alignment takes place in the area of the piston skirt on the counterpressure side through the axial surface line existing there in a straight line over a larger area. The straight generatrix extends there from the lower end of the shaft to about 15% before the upper end of the shaft. On the pressure side, on the other hand, the axial generatrix is essentially spherical. When the piston tilts back from the counterpressure side to the pressure side in the top dead center position of the piston, the piston can roll smoothly on the pressure-side spherical shaft shape. This results in an additional improvement in the piston skirt running noise.

Die entscheidende Geräuschminderung liegt jedoch dar­in, daß der Kolbenkopf an seinem Umfang an der Gegen­druckseite durch den dort geneigten Schaftmantel aus­reichend Abstand zu der Zylinderlauffläche besitzt, um dort bei Teillast oder noch nicht betriebswarmem Motor nicht an die Zylinderwand anzuschlagen.The decisive noise reduction, however, lies in the fact that the circumference of the piston head on the counter-pressure side is sufficiently distant from the cylinder running surface due to the shaft jacket which is inclined there. so as not to hit the cylinder wall under partial load or when the engine is not yet warm.

Die Neigung der axialen Mantellinie des Schaftes auf der Gegendruckseite wird in einem solchen Maße ge­wählt, daß im Vollastbetrieb durch den Regeleffekt des Regelstreifens 4 sich ein paralleler Verlauf die­ser Mantellinie zu der Längsachse X einstellt. Der Regelstreifen 4 ist direkt am oberen Ende des Schaf­tes angebracht und reicht im dargestellten Beispiel über eine Höhe von 25% der Schaftgesamtlänge. Der Durchmesser des Feuerstegs des Kolbenkopfes ist ge­ringer als der maximale Durchmesser des Kolbenschaf­tes. Fig. 4 zeigt recht deutlich, wie der Kolbenkopf durch den Schaft bei kaltem Kolben in eine solche Schieflage gebracht wird, daß das Spiel zwischen Ringpartie und Zylinderlauffläche auf der Gegendruck­seite des Kolbens deutlich größer ist als auf der diametral gegenüberliegenden Druckseite des Kolbens. Dadurch wird das Kolbengeräusche verursachende An­schlagen der Ringpartie vermieden.The inclination of the axial surface line of the shaft on the counter-pressure side is chosen to such an extent that, in full-load operation, the control effect of the control strip 4 results in a parallel profile of this surface line to the longitudinal axis X. The control strip 4 is attached directly to the upper end of the shaft and in the example shown extends over a height of 25% of the total shaft length. The diameter of the top land of the piston head is less than the maximum diameter of the piston skirt. Fig. 4 shows quite clearly how the piston head is brought into such an inclined position by the shaft when the piston is cold, that the play between the ring portion and the cylinder running surface on the counterpressure side of the piston is significantly greater than on the diametrically opposite pressure side of the piston. This prevents the ring part from striking the piston, which causes the piston noise.

In den Fig. 7 und 8 ist in stark überzeichnetem Maß­stab der umfangsmäßige Mantellinienverlauf des Kol­benschaftes in zwei übereinanderliegenden Ebenen dargestellt.7 and 8, the circumferential surface line profile of the piston skirt is shown in two superimposed planes on a greatly exaggerated scale.

Bei dem Kolben nach Fig. 9 ist zusätzlich zu dem im oberen Schaftbereich auf der Gegendruckseite angeord­neten Regelstreifen 4 noch im unteren Schaftbereich auf der Druckseite ein weiterer Regelstreifen 5 ein­gelegt. Die Regelstreifen 4 und 5 erstrecken sich je­ weils von einem der beiden Naben 6-Bereiche umfangs­mäßig bis vor die senkrecht zur Kolbenbolzenachse verlaufende Kolbenkippebene, d.h. die Regelstreifen sind umfangsmäßig im Bereich der Kolbenkippebene von­einander getrennt. Insbesondere aus Gründen eines vereinfachten Einbringens der Regelstreifen beim Gie­ßen der Kolben sind jeweils ein Regelstreifen 4 und 5 zu einem gemeinsamen im Bereich der Kolbennabe 6 ver­bundenen Regelstreifen 7 verbunden.In the piston according to FIG. 9, in addition to the control strip 4 arranged in the upper shaft area on the counter pressure side, a further control strip 5 is inserted in the lower shaft area on the pressure side. The control strips 4 and 5 each extend Weil of one of the two hubs 6 areas circumferentially up to the piston tilt plane running perpendicular to the piston pin axis, ie the control strips are circumferentially separated from one another in the area of the piston tilt plane. In particular for reasons of a simplified introduction of the control strips when casting the pistons, control strips 4 and 5 are connected to a common control strip 7 connected in the region of the piston hub 6.

Durch die Regelstreifen 5 im unteren Schaftbereich auf der Druckseite kann der Kolben in diesem unteren Schaftbereich im Kaltzustand mit einem dort derart engen radialenSpiel eingebaut werden, daß auf der Ge­gendruckseite eine Anlage an den dort von oben nach unten innen geneigten Schaftmantel gefördert wird. Dadurch kommt der Kolben beim Kippen zur Gegendruck­seite früher mit der druckseitigen Schaftunterseite zur Anlage, wodurch der Kippwinkel reduziert wird.By means of the control strips 5 in the lower shaft area on the pressure side, the piston can be installed in this lower shaft area in the cold state with a radial play so narrow there that on the counter-pressure side an attachment to the shaft jacket inclined from top to bottom is promoted. As a result, when the piston tilts to the counter pressure side, it comes into contact with the underside of the shaft on the pressure side earlier, which reduces the tilt angle.

Über die axiale Höhe wird der Kolbenschaft dadurch in seiner Steifheit verändert, daß die tragenden Schaft­flächen umfangsmäßig ungleich breit sind und jeweils an dem umfangsmäßigen Ende nach radial innen abge­stützt sind. Die unterschiedliche Elastizität in axialer Richtung wird dabei so verteilt, daß der Kol­benschaft auf der Gegendruckseite im oberen Bereich, in dem sich der Regelstreifen 4 befindet steifer als in dem darunterliegenden Schaftbereich geführt ist. Auf der Druckseite wird dagegen der untere Schaftbe­reich steifer ausgeführt als derjenige auf der Gegen­druckseite gegenüberliegende untere Schaftbereich.The stiffness of the piston shaft is changed over the axial height in that the load-bearing shaft surfaces are unequal in circumference and are supported radially inwards at the circumferential end. The different elasticity in the axial direction is distributed in such a way that the piston skirt on the counter pressure side in the upper area, in which the control strip 4 is located, is stiffer than in the skirt area below. On the pressure side, on the other hand, the lower shaft area is made stiffer than the lower shaft area opposite on the counter pressure side.

Die die tragenden Schaftflächen 8, 9 in Richtung zur Kolbenachse verbindenden Wände 10 sind in ihrem Ver­lauf durch die Form der sich über die Höhe des Schaf­tes verändernden Tragflächen 8, 9 vorgegeben. Die Na­ben 6 können radial über diese Wände 10 hinausragen. Am unteren Schaftende kann aus fertigungstechnischen Gründen ein schmaler umlaufender Ringbund 11 vorgese­hen sein. Ein solcher Ringbund ermöglicht es, den Kolben rollend durch die einzelnen Fertigungsstatio­nen zu transportieren.The course of the walls 10 connecting the supporting shaft surfaces 8, 9 in the direction of the piston axis is predetermined by the shape of the bearing surfaces 8, 9 which change over the height of the shaft. The hubs 6 can protrude radially beyond these walls 10. At the lower end of the shaft, a narrow circumferential collar 11 can be provided for manufacturing reasons. Such a collar enables the piston to be transported in a rolling manner through the individual production stations.

Claims (16)

1. A light-metal trunk piston for internal combustion engines with a piston head containing the piston ring grooves and a piston skirt connecting below the lowermost ring groove with the following characteristics:
- the piston head has a longitudinal axis X which is the axis for its axial generating lines,
- the piston skirt is separated from the piston head on the counter-pressure side by a transversal slit,
- inside the piston skirt adjustment strips (4) are provided on its upper end, the material of these possessing a lower heat expansion coefficient relative to the light metal of the piston, characterized by the characteristics that
the adjustment strips (4) are restricted to the half of the skirt situated on the counter-pressure side,
at least in the cold state of the piston the generating line (DK) of the pressure side is curved,
in the cold state of the piston the generating line on the counter-pressure side (GK) extends if such a way that at least in the centre third or the skirt height its distance relative to the longitudinal axis X towards the skirt end diminishes continuously and in this height region is substantially rectilinear.
2. A light-metal trunk piston for internal combustion engines with a piston head containing the piston ring grooves and a piston skirt connecting below the lowermost ring groove with the following characteristics:
- the piston head has a longitudinal axis X which is the axis for its axial generating lines,
- the piston skirt is separated from the piston head on the counter-pressure side by a transversal slit,
- inside the piston skirt adjustable strips (4) are provided on its upper end, the material of these possessing a lower heat expansion coefficient relative to the light metal of the piston, characterized by the characteristics that
the adjustment strips (4) situated on the upper end of the piston skirt are restricted to the half of the skirt situated on the counter-pressure side,
in the cold state of the piston the generating line on the counter-pressure side (GK) extends in such a way that at least in the centre third of the skirt height its distance relative to the longitudinal axis X towards the skirt end diminishes continuously and in this height region is substantially rectilinear,
on the pressure side half of the skirt further adjustment strips (5) are provided on its lower end, the material of these strips possessing a lower heat expansion coefficient relative to the light metal of the piston,
in the region of these adjustment strips (5), in the cold state of the piston, the radial distance of the skirt generating lines (DK) on the pressure side is at the greatest value relative to the longitudinal axis of the piston.
3. A light-metal trunk piston according to claim 1 or 2, characterized in that the piston skirt, at its upper region, on the counter-pressure side, applies over a smaller outline on the wall of the motor cylinder than on the pressure side, while this, in the lower skirt region is exactly the reverse, and in that the skirt portions applying on the cylinder wall are respectively supported on their circumferential ends over the height of the skirt in the direction of the piston axis, the skirt surfaces running onto the cylinder wall being directed symmetrically to the piston canting surface (the plane incorporating the longitudinal axis of the piston and extending perpendi­cularly to the gudgeon pin axis), and it being possible to provide on the lower skirt end as a closure a narrow annular band extending over the entire circumference.
4. A light-metal trunk piston according to are of the foregoing claims, characterized in that the adjustment strips (4) situated on the pressure side and the counter­pressure side (4, 5) are joined together.
5. A light-metal trunk piston according to claim 4, characterized in that altogether provision is made for two adjustment strips, of which each one passes through one of the two boss areas (6) of the piston and ends respectively in front of the piston canting plane.
6. A light-metal trunk piston according to one of the foregoing claims, characterized in that in the cold state of the piston the generating line (GK) on the counter­pressure side extends in such a way that in a region between the lower end and the upper quarter of the piston skirt its distance relative to the longitudinal axis X to the skirt end diminishes continuously.
7. A light-metal trunk piston according to claim 6, characterized in that in the cold state of the piston the generating line (GK) on the counter-pressure side extends in such a way that in a region between the lower end and the upper ten per cent of the height of tie piston skirt its distance relative to the longitudinal axis X to the skirt end diminishes continuously.
8. A light-metal trunk piston according to one of the foregoing claims, characterized in that the course of the generating line (GK) on the counter-pressure side defined in the characterizing characteristics of claims 1 and 2 extends over an extent of at least 30 degrees.
9. A light-metal trunk piston according to one of the fore­going claims, characterized by the following dimensions:
L = (0.45 - 0.65) × D
A = (0.25 - 0.4 ) × D
H = (0.3 - 0.4) × D wherein
D = maximum diameter of the piston
L = maximum length of the piston
H = compression height
A = mean skirt height below the lowermost ring groove in a circumferential area with substantially the same skirt height of at least 60 degrees both on the pressure and the counter-pressure side.
EP88903796A 1987-04-18 1988-04-15 Light-metal trunk piston for internal combustion engines Expired - Lifetime EP0356457B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3713242A DE3713242C1 (en) 1987-04-18 1987-04-18 Light metal plunger for internal combustion engines
DE3713242 1987-04-18

Publications (2)

Publication Number Publication Date
EP0356457A1 EP0356457A1 (en) 1990-03-07
EP0356457B1 true EP0356457B1 (en) 1991-02-27

Family

ID=6325934

Family Applications (1)

Application Number Title Priority Date Filing Date
EP88903796A Expired - Lifetime EP0356457B1 (en) 1987-04-18 1988-04-15 Light-metal trunk piston for internal combustion engines

Country Status (6)

Country Link
US (1) US5000078A (en)
EP (1) EP0356457B1 (en)
JP (1) JP2690340B2 (en)
BR (1) BR8807471A (en)
DE (2) DE3713242C1 (en)
WO (1) WO1988008078A1 (en)

Families Citing this family (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2983621B2 (en) * 1988-12-24 1999-11-29 マーレ ゲゼルシャフト ミット ベシュレンクテル ハフツング Lightweight cylindrical piston for internal combustion engines
DE3843761A1 (en) * 1988-12-24 1990-07-05 Mahle Gmbh Light trunk piston for internal combustion engines
DE3843866A1 (en) * 1988-12-24 1990-06-28 Mahle Gmbh Light trunk piston for internal combustion engines
DE3931949A1 (en) * 1989-09-25 1991-04-04 Alcan Gmbh PISTON FOR A COMBUSTION ENGINE
US5107807A (en) * 1989-09-28 1992-04-28 Nissan Motor Company, Ltd. Piston for internal combustion engine
DE4109160C3 (en) * 1991-03-20 2000-11-30 Federal Mogul Nuernberg Gmbh Pistons for internal combustion engines
JPH11303674A (en) 1998-04-24 1999-11-02 Unisia Jecs Corp Piston for internal combustion engine
US7293497B2 (en) 2005-11-03 2007-11-13 Dresser, Inc. Piston
US7302884B2 (en) * 2005-11-03 2007-12-04 Dresser, Inc. Piston
DE102008029071B4 (en) * 2008-06-10 2019-12-24 Dr. Ing. H.C. F. Porsche Aktiengesellschaft Pistons for an internal combustion engine
DE102008002536B4 (en) * 2008-06-19 2015-02-12 Federal-Mogul Nürnberg GmbH Piston for an internal combustion engine
DE102009032379A1 (en) * 2008-08-13 2010-02-18 Mahle International Gmbh Piston for an internal combustion engine
DE102011080822A1 (en) 2011-08-11 2013-02-14 Mahle International Gmbh piston
US10753310B2 (en) 2012-02-10 2020-08-25 Tenneco Inc. Piston with enhanced cooling gallery
JP2015511676A (en) 2012-03-12 2015-04-20 フェデラル−モーグル コーポレイション Engine piston
DE112013005725T5 (en) * 2012-11-30 2015-08-13 Cummins Ip, Inc. Engine cylinder and bushing assembly
DE102013009164A1 (en) * 2013-05-31 2014-12-04 Mahle International Gmbh Piston for an internal combustion engine
US9759156B2 (en) * 2015-03-04 2017-09-12 Mahle International Gmbh Asymmetric piston
US20170254291A1 (en) * 2016-03-02 2017-09-07 Federal-Mogul Llc Galleryless piston with slotted ring groove
JP2018145861A (en) * 2017-03-06 2018-09-20 日野自動車株式会社 Piston structure

Family Cites Families (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1825750A (en) * 1926-10-25 1931-10-06 Cleveland Trust Co Piston
US2086677A (en) * 1934-07-19 1937-07-13 Adolph L Nelson Piston
US2110346A (en) * 1934-07-31 1938-03-08 Perfect Circle Co Piston
FR812385A (en) * 1936-07-20 1937-05-08 Monsieur Friedrich Richard Die One piece skirted light metal piston
US2551488A (en) * 1948-02-18 1951-05-01 Thompson Prod Inc Controlled expansion piston
GB1256242A (en) * 1968-09-05 1971-12-08 Ass Eng Ltd Improvements in pistons
US3908521A (en) * 1972-07-31 1975-09-30 Hepworth & Grandage Ltd Pistons for internal combustion engines or for compressors
GB1505148A (en) * 1975-08-12 1978-03-30 Hepworth & Grandage Ltd Pistons
JPS5781144A (en) * 1980-11-10 1982-05-21 Yamaha Motor Co Ltd Piston for internal combustion engine
DE3430132A1 (en) * 1984-08-16 1986-02-27 Mahle Gmbh, 7000 Stuttgart ALUMINUM IMMERSION PISTON FOR COMBUSTION ENGINES WITH CONTROL STRIPS
JPH0750049Y2 (en) * 1986-11-25 1995-11-15 イズミ工業株式会社 Strut for thermal expansion suppression piston

Also Published As

Publication number Publication date
EP0356457A1 (en) 1990-03-07
DE3861855D1 (en) 1991-04-04
JPH02503104A (en) 1990-09-27
DE3713242C1 (en) 1988-10-20
BR8807471A (en) 1990-05-22
JP2690340B2 (en) 1997-12-10
US5000078A (en) 1991-03-19
WO1988008078A1 (en) 1988-10-20

Similar Documents

Publication Publication Date Title
EP0356457B1 (en) Light-metal trunk piston for internal combustion engines
DE2620910C2 (en) Pistons for an internal combustion engine
DE2625191C2 (en) One-piece piston for internal combustion engines
DE3518721C3 (en) Oil-cooled, multi-part plunger of an internal combustion engine
EP0009269B1 (en) Light-metal piston for internal combustion engines
DE2253961A1 (en) PISTON ASSEMBLY
DE4014705C2 (en) Cooled plunger for internal combustion engines with separate piston upper part and piston skirt
DE3502644A1 (en) OIL-COOLED, MULTI-PIECE SUBMERSIBLE PISTON FOR PISTON PISTON COMBUSTION ENGINES
EP0171568B1 (en) Piston for internal-combustion engines with expansion-controlling inserts
EP0449848B1 (en) Light plunger piston for internal combustion engines
EP0181652B1 (en) Light-metal piston
EP0030399B1 (en) Light metal piston
DE1078387B (en) Aluminum pistons with curved control elements cast in the shaft
EP0050256A1 (en) Light-weight piston for internal-combustion engines
WO1996038683A1 (en) Arrangement of piston and connecting rod for internal combustion engines
EP0327595B1 (en) Single-piece, lightweight and low-friction light-metal piston for internal combustion engines
DE2734519A1 (en) LIGHT ALLOY PISTON
DE3446121A1 (en) Light, extremely flat trunk piston for internal combustion engines
DE2430829A1 (en) PISTONS FOR COMBUSTION ENGINES
DE3742616A1 (en) One-part, light and low-frictional light-metal piston for internal-combustion engines
DE19733814C2 (en) Engine pistons
DE3723005C2 (en) Plunger pistons for internal combustion engines
DE3643198C2 (en)
DE3511557A1 (en) LIGHT METAL CONTROL PISTON
DE3626436C2 (en)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19890718

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE FR GB IT

17Q First examination report despatched

Effective date: 19900702

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

ITF It: translation for a ep patent filed

Owner name: DE DOMINICIS & MAYER S.R.L.

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE FR GB IT

ET Fr: translation filed
GBT Gb: translation of ep patent filed (gb section 77(6)(a)/1977)
REF Corresponds to:

Ref document number: 3861855

Country of ref document: DE

Date of ref document: 19910404

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

26N No opposition filed
PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20010323

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20010420

Year of fee payment: 14

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: DE

Payment date: 20010511

Year of fee payment: 14

REG Reference to a national code

Ref country code: GB

Ref legal event code: IF02

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20020415

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20021101

GBPC Gb: european patent ceased through non-payment of renewal fee

Effective date: 20020415

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FR

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20021231

REG Reference to a national code

Ref country code: FR

Ref legal event code: ST

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20050415