WO2013097913A1 - Plastic gear wheel having a foam core, and method therefor - Google Patents

Plastic gear wheel having a foam core, and method therefor Download PDF

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Publication number
WO2013097913A1
WO2013097913A1 PCT/EP2012/004589 EP2012004589W WO2013097913A1 WO 2013097913 A1 WO2013097913 A1 WO 2013097913A1 EP 2012004589 W EP2012004589 W EP 2012004589W WO 2013097913 A1 WO2013097913 A1 WO 2013097913A1
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WO
WIPO (PCT)
Prior art keywords
gear
plastic
core
wall
gear according
Prior art date
Application number
PCT/EP2012/004589
Other languages
German (de)
French (fr)
Inventor
Michael Kastrup
Original Assignee
Gm Tec Industries Holding Gmbh
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Publication date
Application filed by Gm Tec Industries Holding Gmbh filed Critical Gm Tec Industries Holding Gmbh
Publication of WO2013097913A1 publication Critical patent/WO2013097913A1/en

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C44/00—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
    • B29C44/02—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles
    • B29C44/04—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities
    • B29C44/0461—Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles for articles of definite length, i.e. discrete articles consisting of at least two parts of chemically or physically different materials, e.g. having different densities by having different chemical compositions in different places, e.g. having different concentrations of foaming agent, feeding one composition after the other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
    • B29C45/16—Making multilayered or multicoloured articles
    • B29C45/1642—Making multilayered or multicoloured articles having a "sandwich" structure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2105/00—Condition, form or state of moulded material or of the material to be shaped
    • B29K2105/04—Condition, form or state of moulded material or of the material to be shaped cellular or porous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
    • B29L2015/00—Gear wheels or similar articles with grooves or projections, e.g. control knobs
    • B29L2015/003—Gears
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H55/00—Elements with teeth or friction surfaces for conveying motion; Worms, pulleys or sheaves for gearing mechanisms
    • F16H55/02—Toothed members; Worms
    • F16H55/06—Use of materials; Use of treatments of toothed members or worms to affect their intrinsic material properties
    • F16H2055/065—Moulded gears, e.g. inserts therefor

Definitions

  • Plastic gear with foamed core and a method to do so
  • plastic gears It is known to use plastic gears in various applications of transmission technology in powertrains and power trains.
  • the plastic gears used are generally less capable of transmitting power than metal gears. It will be
  • Tooth contours of the gears are machined from semi-finished, z. B. by milling.
  • the molds used in casting processes generally have the final tooth contour, so that the teeth are not further processed.
  • the document DE 3414842 describes a gear made of a plastic, which has radial spokes, which are connected at their outer ends by a ring with each other, around whose circumference the sprocket extends. In both end faces of the ring in each case an annular groove is embedded, which separates the ring over a certain part of its height from the sprocket.
  • the publication DE 10 2007 063 422 describes a plastic gear wheel, wherein here the peripheral portion of the gear including a tooth portion consists of plastic material.
  • the inner peripheral member of the gear is provided with a ring or disc shape on the inner peripheral side of the peripheral portion of the gear, wherein the peripheral portion of the gear
  • the manufacture of the gear can be done inter alia by a multi-component injection molding process.
  • the shrinkage may be linear as well as non-linear to the material thickness, so that stresses arise in the interior of the gears and the manufacturing accuracy, especially in the area of the toothing decreases.
  • Cogs already have recesses so that spokes and struts stop like a truss.
  • the recesses reduce the amount of material between the gear outer surface and the gear hub. A reduced
  • Quantity of material causes on the one hand a poorer force distribution of the inner power lines. On the other hand causes the introduction of spokes and struts inhomogeneous shrinkage. Due to the uneven shrinkage occurs inaccuracy in the gearing geometry, which in turn to a
  • Micro-stresses which lead to material damage in the contact area during force peaks.
  • the object of the invention is to overcome the disadvantages listed above. It is a gear to be produced by a simple process, which has only small deviations in production after casting.
  • This object is achieved by a method which results in an improved gear by performing the multi-component injection molding by first injecting the gear outer wall-forming plastic into the cavity of a mold and directly following the gear core (the
  • the (remaining) cavity of the mold is injected.
  • the resulting gear is firstly not homogeneous in its material properties, at the same time has a compact outer skin and has thirdly traversed by cells / gas inclusions core.
  • Azodicarbonamide or sulfohydrazide allows the production of the gear in just one step. Thus, advantageously only one mold is needed for the production. It is advantageous that the production time thereby in comparison to the multi-stage production, for. B. with different materials, is significantly shortened.
  • the gear has optimum thermal conductivity, since there are no recesses. Another advantage is that the weight of the gear is lower compared to solid material due to a foamed core.
  • the gear 1 has a tooth wall 2 forming the plastic wall, which consists of a non-foamed plastic material.
  • Tooth outer wall 2 has the thickness d1 and d2, the tooth width b and the
  • the thicknesses d1 and d2 of the tooth outer wall 2 may differ in their thicknesses.
  • the thicknesses d1 and d2 are equally strong at all points of the outer wall of the gear. This means that the thickness d2, which is present below the tooth bottoms 5 of the teeth 6, is identical to the thickness d1 at the end faces 6 and 7 of the toothed wheel 1.
  • Opening is introduced into the mold.
  • the plastic that forms the tooth outer wall 2 is first injected. Without interruption will be in
  • the sectional view of the gear 1 shows the injection range of the
  • Foam core 3 is injected.
  • the gear 1 is therefore not homogeneous in its material properties, but has a compact outer wall 3, which is harder than the cell / gas inclusions 11 traversed core. 2
  • a feature not shown in FIG. 1 is that the compact outer wall 2 is free of cells or gas inclusions 11.
  • the gear core 3, however, has cells / gas inclusions 11.
  • a further embodiment of the invention has the feature that the outer wall 2 has the thickness (d1), which is 10% to 40%, preferably 15% to 20% compared to the gear width (b).
  • the outer wall 2 has a thickness (d2) which is 10% to 40%, preferably 0% to 5% compared to
  • Root diameter (df) is.
  • the thickness of the outer wall 2 may be identical at all points of the gear.
  • the gear 1 consists of the injection molding plastic polyoxymethylene, polyamide, polybutylene terephthalate, polyphenylene sulfide,
  • Polyetheretherketone or polypropylene are Polyetheretherketone or polypropylene.
  • the plastic component forming the inner core 3 of the Zahnradesl contains additives that give the plastic a higher strength.
  • fiber or carbon fiber inputs are provided in the plastic. This is to be provided in particular in a further embodiment in which the gear 1 is to transmit large powers.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Thermal Sciences (AREA)
  • Gears, Cams (AREA)
  • Injection Moulding Of Plastics Or The Like (AREA)

Abstract

The invention relates to a method for producing a gear wheel (1) by means of multi-component injection molding, wherein the multi-component injection molding process is carried out so that initially a plastic forming the gear wheel outer wall (2) is injected into the cavity of a mold and an expanding plastic forming the gear wheel core (3) (gear interior) is injected immediately thereafter into the rest (remainder) of the mold cavity.

Description

Kunststoffzahnrad mit geschäumtem Kern und ein Verfahren dazu  Plastic gear with foamed core and a method to do so
Es ist bekannt, Zahnräder aus Kunststoff in verschiedenen Anwendungsbereichen der Getriebetechnik in Antriebs- und Kraftsträngen einzusetzen. Die zum Einsatz kommenden Kunststoffzahnräder weisen im Allgemeinen eine geringere Fähigkeit auf Leistungen zu übertragen als Zahnräder aus Metall. Dabei werden It is known to use plastic gears in various applications of transmission technology in powertrains and power trains. The plastic gears used are generally less capable of transmitting power than metal gears. It will be
Kunststoffzahnräder entweder durch Gießverfahren hergestellt, oder die Plastic gears either produced by casting, or the
Zahnkonturen der Zahnräder werden aus Halbzeugen herausgearbeitet, z. B. durch Fräsen. Die Formen, die bei Gießverfahren zum Einsatz kommen, weisen dabei im Allgemeinen die schlussendliche Zahnkontur auf, sodass die Zähne nicht weiter bearbeitet werden. Tooth contours of the gears are machined from semi-finished, z. B. by milling. The molds used in casting processes generally have the final tooth contour, so that the teeth are not further processed.
Die Druckschrift DE 3414842 beschreibt ein Zahnrad aus einem Kunststoff, welches radiale Speichen besitzt, die an ihren äußeren Enden durch einen Ring miteinander verbunden sind, um dessen Umfang sich der Zahnkranz erstreckt. In beiden Stirnflächen des Ringes ist jeweils eine Ringnut eingelassen, welche den Ring über einen gewissen Teil seiner Höhe vom Zahnkranz trennt. The document DE 3414842 describes a gear made of a plastic, which has radial spokes, which are connected at their outer ends by a ring with each other, around whose circumference the sprocket extends. In both end faces of the ring in each case an annular groove is embedded, which separates the ring over a certain part of its height from the sprocket.
Die Druckschrift DE 10 2007 063 422 beschreibt ein Kunststoffzahnrad, wobei hier der Peripherieabschnitt des Zahnrads einschließlich eines Zahnabschnittes aus Kunststoffmaterial besteht. Das innere Umfangselement des Zahnrads ist mit einer Ring- oder Scheibenform an der inneren Umfangsseite des Peripherieabschnittes des Zahnrads versehen, wobei der Peripherieabschnitt des Zahnrads The publication DE 10 2007 063 422 describes a plastic gear wheel, wherein here the peripheral portion of the gear including a tooth portion consists of plastic material. The inner peripheral member of the gear is provided with a ring or disc shape on the inner peripheral side of the peripheral portion of the gear, wherein the peripheral portion of the gear
einschließlich des Zahnabschnittes aus einem inneren Kern aus Kunststoff mit großem Elastizitätsmodul und hoher Festigkeit besteht und ein Oberflächenschichtelement aus Kunststoff mit relativ kleinem Elastizitätsmodul den inneren Kern umschließt. Die Herstellung des Zahnrades kann unter anderem durch ein Mehrkomponenten-Spritzgußverfahren erfolgen. including the tooth portion made of an inner core made of plastic with high elastic modulus and high strength, and a Plastic surface layer element with relatively small elastic modulus encloses the inner core. The manufacture of the gear can be done inter alia by a multi-component injection molding process.
Die bekannten Kunststoffzahnräder weisen aufgrund der Grenzen der Fertigung verschiedene Probleme auf. Zahnräder aus nur einem Material weisen nach Ihrer Herstellung während der Trocknungs- bzw. Aushärtungsphase eine The known plastic gears have various problems due to the limits of manufacturing. Cog wheels made of only one material have a production after their preparation during the drying or curing phase
„Schrumpfung" in Dicke und Durchmesser auf. Die Schrumpfung kann dabei linear als auch nichtlinear zur Materialdicke sein, sodass hierdurch im Inneren der Zahnräder Spannungen entstehen und die Fertigungsgenauigkeit, insbesondere im Bereich der Verzahnung, sinkt. The shrinkage may be linear as well as non-linear to the material thickness, so that stresses arise in the interior of the gears and the manufacturing accuracy, especially in the area of the toothing decreases.
Um mögliche Schrumpfungen bei Zahnrädern zu verringern, erhalten die To reduce possible shrinkages in gears, get the
Zahnräder bereits Aussparungen, so dass Speichen und Streben wie bei einem Fachwerk stehen bleiben. Die Aussparungen reduzieren die Materialmenge zwischen der Zahnradaußenfläche und der Zahnradnabe. Eine reduzierte Cogs already have recesses so that spokes and struts stop like a truss. The recesses reduce the amount of material between the gear outer surface and the gear hub. A reduced
Materialmenge bewirkt zum einen einen schlechteren Kräfteverlauf der inneren Kraftwirklinien. Zum anderen bewirkt das Einbringen von Speichen und Streben eine inhomogene Schrumpfung. Durch die ungleiche Schrumpfung tritt eine Ungenauigkeit in der Verzahnungsgeometrie auf, die wiederum zu einer Quantity of material causes on the one hand a poorer force distribution of the inner power lines. On the other hand causes the introduction of spokes and struts inhomogeneous shrinkage. Due to the uneven shrinkage occurs inaccuracy in the gearing geometry, which in turn to a
Geräuschentwicklung sowie einer Undefinierten Kraftübertragung führt. Die schlechte Wärmeleitfähigkeit des Kunststoffes führt zu Temperaturschwankungen, die durch eine unterschiedliche Materialdicke des Zahnrades zu einer Noise and an undefined power transmission leads. The poor thermal conductivity of the plastic leads to temperature fluctuations caused by a different material thickness of the gear to a
Temperaturschwankung führt. Dies führt zu einer inhomogenen Schrumpfung des Kunststoffes und somit zu einer verringerten Lebenszeit des Zahnrades, Temperature variation leads. This leads to an inhomogeneous shrinkage of the plastic and thus to a reduced lifetime of the gear,
Der Einsatz von unterschiedlichen Materialien innerhalb des Zahnrades ist zum einen sehr teuer, da in einem mehrstufigen Verfahren mindestens zuerst der Kern gespritzt werden muss. Im Anschluss an das Spritzen des Kernes wird dann der umhüllende Teil gespritzt. Da in der Spritztechnik neben dem herzustellenden Zahnrad aber immer auch noch zumindest der/die Einspritzkanal/-kanäle entstehen, ist davon auszugehen, dass zwischen den beiden Fertigungsschritten zumindest ein Bearbeitungsschritt, zum Entfernen der Reste, notwendig ist. Es ist davon auszugehen, dass sogar mehrere Bearbeitungsschritte erforderlich sind. Der Einsatz von unterschiedlichen Materialien innerhalb des Zahnrades ruft zum Anderen weitere Probleme hervor. Es kommt aufgrund unterschiedlicher The use of different materials within the gear is on the one hand very expensive, since in a multi-stage process at least the first core must be injected. Following the injection of the core, the enveloping part is then injected. Since, in addition to the gearwheel to be produced, in injection molding technology at least the injection channel (s) also always arise, it can be assumed that at least one processing step for removing the residues is necessary between the two production steps. It can be assumed that even several processing steps are required. The use of different materials within the gear on the other causes further problems. It comes because of different
Materialeigenschaften zu keiner einheitlich guten Verbindung zwischen den unterschiedlichen Materien. Die Kontaktbereiche zwischen den Materialien weisen keine homogene Flächenstruktur auf. Die Kraftwirklinien innerhalb des Zahnes sind somit unterbrochen. Nur aufgrund von Oberflächenrauheit und Formschluss kann eine Kraftleitung zwischen den Materialien erfolgen. Dabei entstehen Material properties to no uniform good connection between the different materials. The contact areas between the materials do not have a homogeneous surface structure. The power lines within the tooth are thus interrupted. Only due to surface roughness and positive locking can be a power line between the materials. Thereby arise
Mikrospannungen, die bei Kraftspitzen zu Materialschäden im Kontaktbereich führen. Micro-stresses, which lead to material damage in the contact area during force peaks.
Aufgabe der Erfindung ist es, die oben aufgeführten Nachteile zu überwinden. Es soll ein Zahnrad durch ein einfaches Verfahren hergestellt werden, welches nach dem Gießen nur geringe Fertigungsabweichungen aufweist. The object of the invention is to overcome the disadvantages listed above. It is a gear to be produced by a simple process, which has only small deviations in production after casting.
Diese Aufgabe wird durch ein Verfahren gelöst, welches zu einem verbesserten Zahnrad führt, indem der Mehrkomponenten-Spritzguss derart ausgeführt wird, dass zuerst der die Zahnradaußenwand bildende Kunststoff in den Hohlraum einer Form eingespritzt wird und darauf direkt folgend der den Zahnradkern (das This object is achieved by a method which results in an improved gear by performing the multi-component injection molding by first injecting the gear outer wall-forming plastic into the cavity of a mold and directly following the gear core (the
Zahnradinnere) bildende, sich aufblähende Kunststoff in den verbliebenen Gear inside) forming, inflating plastic in the remaining
(restlichen) Hohlraum der Form eingespritzt wird. Das hierdurch entstehende Zahnrad ist erstens in seinen Materialeigenschaften nicht homogen, weist gleichzeitig eine kompakte Außenhaut auf und besitzt drittens einen von Zellen / Gaseinschlüssen durchzogenen Kern. (remaining) cavity of the mold is injected. The resulting gear is firstly not homogeneous in its material properties, at the same time has a compact outer skin and has thirdly traversed by cells / gas inclusions core.
Vorteilhaft ist, dass nur ein Basismaterial für die Herstellung des Zahnrades benötigt wird. It is advantageous that only a base material for the production of the gear is needed.
Von Vorteil ist, dass das sequenzielle Einbringen desselben Materials mit unterschiedlichen Zusatzstoffen (z. B. bei physikalischen Treibmitteln wie z.B. Kohlendioxid oder Stickstoff sowie bei chemischen Treibmitteln wie z.B. It is advantageous that the sequential introduction of the same material with different additives (for example, physical blowing agents such as carbon dioxide or nitrogen and chemical blowing agents such.
Azodicarbonamid oder Sulfohydrazide) die Herstellung des Zahnrades in nur einem Schritt ermöglicht. Somit wird vorteilhafterweise für die Fertigung nur eine Gießform benötigt. Von Vorteil ist, dass die Herstellungszeit hierdurch im Vergleich zur mehrstufigen Fertigung, z. B. bei unterschiedlichen Materialien, deutlich verkürzt wird. Azodicarbonamide or sulfohydrazide) allows the production of the gear in just one step. Thus, advantageously only one mold is needed for the production. It is advantageous that the production time thereby in comparison to the multi-stage production, for. B. with different materials, is significantly shortened.
Von Vorteil ist, dass durch den geschäumten Kern die Schrumpfung bedeutend reduziert wird und die Genauigkeit der Verzahnung erhöht wird. It is advantageous that shrinkage is significantly reduced by the foamed core and the accuracy of the toothing is increased.
Vorteilhaft ist auch, dass das Zahnrad eine optimale Wärmeleitfähigkeit aufweist, da keine Aussparungen vorhanden sind. Von Vorteil ist weiterhin, dass durch einen geschäumten Kern das Gewicht des Zahnrades im Vergleich zu Vollmaterial geringer ist. It is also advantageous that the gear has optimum thermal conductivity, since there are no recesses. Another advantage is that the weight of the gear is lower compared to solid material due to a foamed core.
Ein Ausführungsbeispiel der Erfindung ist in der nachfolgenden Zeichnung im Schnitt dargestellt und wird im Folgenden näher beschrieben. An embodiment of the invention is illustrated in the following drawing in section and will be described in more detail below.
Das Zahnrad 1 weist eine die Zahnaußenwand 2 bildende Kunststoffwand auf, welche aus einem nicht geschäumten Kunststoffmaterial besteht. Die The gear 1 has a tooth wall 2 forming the plastic wall, which consists of a non-foamed plastic material. The
Zahnaußenwand 2 weist die Dicke d1 und d2, die Zahnbreite b sowie den Tooth outer wall 2 has the thickness d1 and d2, the tooth width b and the
Zahnfußkreisdurchmesser df auf. Die Dicken d1 und d2 der Zahnaußenwand 2 können in ihren Dicken unterschiedlich ausgeprägt sein. In der Figur sind die Dicken d1 und d2 an allen Stellen der Außenwand des Zahnrades gleich stark. Dies bedeutet, dass die Dicke d2, die unterhalb der Zahngründe 5 der Zähne 6 vorliegt, identisch ist mit der Dicke d1 an den Stirnseiten 6 und 7 des Zahnrades 1. Tooth root circle diameter df on. The thicknesses d1 and d2 of the tooth outer wall 2 may differ in their thicknesses. In the figure, the thicknesses d1 and d2 are equally strong at all points of the outer wall of the gear. This means that the thickness d2, which is present below the tooth bottoms 5 of the teeth 6, is identical to the thickness d1 at the end faces 6 and 7 of the toothed wheel 1.
Aus der Zeichnung geht weiterhin hervor, dass das Material nur durch eine From the drawing also shows that the material only by a
Öffnung in die Form eingebracht wird. Hierzu wird zuerst der Kunststoff, der die Zahnaußenwand 2 bildet, eingespritzt. Ohne Unterbrechung wird im Opening is introduced into the mold. For this purpose, the plastic that forms the tooth outer wall 2 is first injected. Without interruption will be in
Zweikomponenten-Spritzgussverfahren im Anschluss daran Kunststoff Two-component injection molding process following plastic
eingespritzt, welcher durch Zusatz von aufblähenden Mitteln den Schaumstoffkern 3 des Zahnrades 1 bildet. Durch den Spritzvorgang wird der sogenannte Anguss 4 gebildet. injected, which forms the foam core 3 of the gear 1 by the addition of inflation agents. By spraying the so-called sprue 4 is formed.
Die Schnittdarstellung des Zahnrades 1 zeigt den Einspritzbereich des die The sectional view of the gear 1 shows the injection range of the
Zahnaußenwand 2 bildenden Kunststoffes 10, sowie den innenliegenden Kanal 9 in den der Kunststoff mit dem aufblähenden Mittel (Treibmittel) für den Tooth outer wall 2 forming plastic 10, and the inner channel. 9 in which the plastic with the inflating agent (blowing agent) for the
Schaumstoffkem 3 eingespritzt wird. Foam core 3 is injected.
Das Zahnrad 1 ist somit in seinen Materialeigenschaften nicht homogen, weist jedoch eine kompakte Außenwand 3 auf, welche härter ist als der von Zellen / Gaseinschlüssen 11 durchzogene Kern 2. The gear 1 is therefore not homogeneous in its material properties, but has a compact outer wall 3, which is harder than the cell / gas inclusions 11 traversed core. 2
Bei physikalischen Treibmitteln kann z.B. Kohlendioxid oder Stickstoff verwendet werden. Der Einsatz von chemischen Treibmitteln erfolgt z.B. durch die For physical blowing agents, e.g. Carbon dioxide or nitrogen can be used. The use of chemical blowing agents is e.g. through the
Verwendung von Azodicarbonamid oder Sulfohydrazidev Use of Azodicarbonamide or Sulfohydrazidev
Ein in Figur 1 nicht dargestelltes Merkmal ist, dass die kompakte Außenwand 2 frei von Zellen oder Gaseinschlüssen 11 ist. Der Zahnradkern 3 hingegen weist Zellen/Gaseinschlüsse 11 auf. A feature not shown in FIG. 1 is that the compact outer wall 2 is free of cells or gas inclusions 11. The gear core 3, however, has cells / gas inclusions 11.
Eine weitere Ausführungsform der Erfindung weist das Merkmal auf, dass die Außenwand 2 die Dicke (d1 ) hat, welche 10% bis 40%, vorzugsweise 15% bis 20% im Vergleich zur Zahnradbreite (b) beträgt. A further embodiment of the invention has the feature that the outer wall 2 has the thickness (d1), which is 10% to 40%, preferably 15% to 20% compared to the gear width (b).
In einer anderen Ausführungsform weist die Außenwand 2 eine Dicke (d2) auf, welche 10% bis 40%, vorzugsweise 0% bis 5% im Vergleich zum In another embodiment, the outer wall 2 has a thickness (d2) which is 10% to 40%, preferably 0% to 5% compared to
Fußkreisdurchmesser (df) beträgt. Root diameter (df) is.
Je nach Abmessungen des Zahnrades 1 kann die Dicke der Außenwand 2 an allen Stellen des Zahnrades identisch sein. Depending on the dimensions of the gear 1, the thickness of the outer wall 2 may be identical at all points of the gear.
Je nach Ausführungsform besteht das Zahnrad 1 aus dem Spritzkunststoff Polyoxymethylen, Polyamid, Polybutylenterephthalat, Polyphenylensulfid, Depending on the embodiment, the gear 1 consists of the injection molding plastic polyoxymethylene, polyamide, polybutylene terephthalate, polyphenylene sulfide,
Polyetheretherketon oder Polyprophylen. Polyetheretherketone or polypropylene.
Je nach Ausführungsform enthält der Kunststoffanteil, der den inneren Kern 3 des Zahnradesl bildet, Zusätze, die dem Kunststoff eine höhere Festigkeit verleihen. Hierzu sind Glasfaser- oder Kohlefasereingaben in den Kunststoff vorzusehen. Dies ist insbesondere in einer weiteren Ausführungsform vorzusehen, in der das Zahnrad 1 große Leistungen übertragen soll. Depending on the embodiment, the plastic component forming the inner core 3 of the Zahnradesl contains additives that give the plastic a higher strength. For this purpose, fiber or carbon fiber inputs are provided in the plastic. This is to be provided in particular in a further embodiment in which the gear 1 is to transmit large powers.

Claims

Ansprüche claims
1. Verfahren zur Herstellung eines Zahnrades durch Mehrkomponenten- Spritzguss, dadurch gekennzeichnet, dass 1. A method for producing a gear by multi-component injection molding, characterized in that
der Mehrkomponenten-Spritzguss derart ausgeführt wird, dass zuerst ein die Zahnradaußenwand (2) bildender Kunststoff in den Hohlraum einer Form eingespritzt wird und darauf direkt folgend ein den Zahnradkern (3) (das Zahnradinnere) bildender, sich aufblähender Kunststoff in den verbliebenen (restlichen) Hohlraum der Form eingespritzt wird.  the multi-component injection molding is carried out in such a way that first a plastic forming the gear outer wall (2) is injected into the cavity of a mold and directly following this, a plastic core (3) (the gear inside) forming, inflating plastic in the remaining (remaining) Cavity of the mold is injected.
2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, dass das Zahnrad (1) durch ein 2-Komponenten-Spritzgußverfahren hergestellt wird. 2. The method according to claim 1, characterized in that the gear (1) is produced by a 2-component injection molding process.
3. Zahnrad nach dem Verfahren nach Anspruch 1 oder 2, dadurch 3. gear according to the method of claim 1 or 2, characterized
gekennzeichnet, dass der von mit Gas gefüllten Zellen (11 ) durchzogene Kern (3) des Zahnrades (1 ) aus demselben Kunststoff besteht wie das der kompakten Außenwand des Zahnrades (2).  in that the core (3) of the toothed wheel (1) traversed by gas-filled cells (11) consists of the same plastic as that of the compact outer wall of the toothed wheel (2).
4. Zahnrad nach einem der voranstehenden Ansprüche, dadurch 4. Gear according to one of the preceding claims, characterized
gekennzeichnet, dass der Kunststoff des Kerns (3) unter Verwendung von physikalischen Treibmitteln wie z.B. Kohlendioxid oder Stickstoff aufgeschäumt wird.  characterized in that the plastic of the core (3) is made using physical blowing agents, e.g. Carbon dioxide or nitrogen is foamed.
5. Zahnrad nach Anspruch 1 , Anspruch 2 oder Anspruch 3, dadurch 5. Gear according to claim 1, claim 2 or claim 3, characterized
gekennzeichnet, dass der Kunststoff des Kerns (3) unter Verwendung von chemischen Treibmitte wie Azodicarbonamid oder Sulfohydrazide aufgeschäumt wird. in that the plastic of the core (3) is foamed using chemical blowing agents such as azodicarbonamide or sulfohydrazides.
6. Zahnrad nach einem der vorangegangenen Ansprüche, dadurch gekennzeichnet, dass die kompakte Außenwand (2) frei von mit Gas gefüllten Zellen ist. 6. Gear according to one of the preceding claims, characterized in that the compact outer wall (2) is free of gas-filled cells.
7. Zahnrad nach einem der vorangegangenen Ansprüche, dadurch 7. Gear according to one of the preceding claims, characterized
gekennzeichnet, dass die Außenwand (2) des Zahnrades (1) eine Dicke (d1) aufweist, welche 10% bis 40%, vorzugsweise 15% bis 20% im Vergleich zur Zahnradbreite (b) beträgt.  characterized in that the outer wall (2) of the gear (1) has a thickness (d1) which is 10% to 40%, preferably 15% to 20%, compared to the gear width (b).
8. Zahnrad nach einem der vorangegangenen Ansprüche, dadurch 8. Gear according to one of the preceding claims, characterized
gekennzeichnet, dass die Außenwand (2) des Zahnrades (1) eine Dicke (d2) aufweist, welche 10% bis 40%, vorzugsweise 10% bis 15% im Vergleich zum Fußkreisdurchmesser (df) beträgt.  in that the outer wall (2) of the toothed wheel (1) has a thickness (d2) which is 10% to 40%, preferably 10% to 15%, compared to the root diameter (df).
9. Zahnrad nach einem der vorangegangenen Ansprüche, dadurch 9. gear according to one of the preceding claims, characterized
gekennzeichnet, dass das Zahnrad (1 ) aus dem Spritzkunststoff Polyoxymethylen, Polyamid, Polybutylenterephthalat, Polyphenylensulfid, Polyetheretherketon oder Polyprophylen besteht.  in that the gearwheel (1) made of the injection-molded plastic is polyoxymethylene, polyamide, polybutylene terephthalate, polyphenylene sulphide, polyetheretherketone or polyprophylene.
10. Zahnrad nach einem der vorangegangenen Ansprüche, dadurch 10. gear according to one of the preceding claims, characterized
gekennzeichnet, dass dem Kunststoffanteil, der den inneren Kern (3) des Zahnrades (1) bildet, Zusätze zugegeben sind, die die Festigkeit des geschäumten Kerns (4) erhöhen.  in that additives which increase the strength of the foamed core (4) are added to the plastic component which forms the inner core (3) of the toothed wheel (1).
11.Zahnrad nach einem der vorangegangenen Ansprüche dadurch 11.Zahnrad according to one of the preceding claims characterized
gekennzeichnet, dass das Zahnrad (1 ) verstärkende Einlagen enthält.  characterized in that the gear (1) contains reinforcing inserts.
PCT/EP2012/004589 2011-12-30 2012-11-02 Plastic gear wheel having a foam core, and method therefor WO2013097913A1 (en)

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