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EP0425502A1 - Process for machining radial through-slots in piston-ring grooves - Google Patents

Process for machining radial through-slots in piston-ring grooves

Info

Publication number
EP0425502A1
EP0425502A1 EP89906020A EP89906020A EP0425502A1 EP 0425502 A1 EP0425502 A1 EP 0425502A1 EP 89906020 A EP89906020 A EP 89906020A EP 89906020 A EP89906020 A EP 89906020A EP 0425502 A1 EP0425502 A1 EP 0425502A1
Authority
EP
European Patent Office
Prior art keywords
piston
annular groove
areas
slots
cutting tool
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.)
Withdrawn
Application number
EP89906020A
Other languages
German (de)
French (fr)
Inventor
Gotthard Stuska
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 EP0425502A1 publication Critical patent/EP0425502A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B27/00—Tools for turning or boring machines; Tools of a similar kind in general; Accessories therefor
    • B23B27/06—Profile cutting tools, i.e. forming-tools
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23B—TURNING; BORING
    • B23B5/00—Turning-machines or devices specially adapted for particular work; Accessories specially adapted therefor
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T82/00—Turning
    • Y10T82/10—Process of turning
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
    • Y10T82/00—Turning
    • Y10T82/23—Portable lathe for piston grooving

Definitions

  • the invention relates to a method according to the preamble of claim 1.
  • Radial slot openings in the piston ring groove of a piston such as is known, for example, from CH-Z "technica, 1980 H 25/26, pages 2277-2333, picture 12" generally have the purpose of pushing the piston head into the on the pressure and counter-pressure side to separate areas of the piston from the shaft. If the piston ring grooves of a plunger for internal combustion engines are fitted exclusively in the piston head above the shaft, the radial slot openings mentioned are located in the lowest ring groove adjacent to the piston shaft. The oil scraper ring is then inserted into this ring groove.
  • the oil rings are those that are tensioned by a hose spring attached radially on the inside in the oil scraper ring
  • the use of hose springs with a small winding diameter of, for example, less than 2 mm can result in the fact that the hose springs jam in the radial slot openings.
  • the radial slot openings must be smaller Height as the winding diameter of the tube spring. In the previous manufacturing processes, it is often not possible to reliably adhere to narrow tolerances of an axially low slot opening. This applies above all to cast pistons.
  • the slot openings are produced in that in the circumferential areas of the piston in which these openings come to rest, namely in the region of the pressure and counterpressure side of the piston, the piston base material is poured radially inside the ring groove base to be broken through at this point, that a slot is created when the groove is worked in. In these cases, narrow tolerances of the slot openings cannot always be reliably observed.
  • the invention is based on the object of producing the required slot openings with greater accuracy in the most economical way possible.
  • the inner shape of the piston is cast.
  • the piston material is carried out radially within the annular groove 2 with such a small wall thickness that these wall areas can be broken through by a cutting tool 3 with the piston rotating.
  • the cutting tool can be shaped in such a way that it fills the entire axial height of the annular groove 2 and only has at its front region a narrower cutting attachment 4 which is reduced in height to the slot opening to be produced.
  • the slot openings 1 are achieved on the one hand and, on the other hand, corresponding narrow annular groove extensions are produced in the peripheral areas in which no complete openings are to be made. These narrow annular groove extensions have no technical function in those areas and they are only there to be able to rotate the piston past the cutting tool 3.
  • slot breakthroughs with axial heights down to about 0.5-0.8 mm can be produced very precisely in pistons with a cast internal shape.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)
  • Turning (AREA)
  • Cutting Tools, Boring Holders, And Turrets (AREA)

Abstract

Un piston comprend des fentes de passage ménagées dans une gorge annulaire qui s'étendent radialement jusqu'à l'espace intérieur du piston. Ces fentes dans la direction de la circonférence de la gorge annulaire correspondant se situent exclusivement dans les régions du côté de pression/contre-pression du piston, alors que la paroi du piston radialement adjacente au fond de la gorge présente dans les régions pourvues de fentes une épaisseur inférieure à celle des zones de la circonférence non pourvues de fentes. Afin d'obtenir aisément des fentes de passage de dimensions exactes, un outil de coupe (3) stationnaire enclenche la gorge annulaire (2) d'un piston mis en rotation autour de son axe longitudinal. L'outil de coupe enlève du matériau du fond radialement fermé de la gorge annulaire (2), sur toute la circonférence de celle-ci et sur une hauteur prédéterminée par la forme de l'outil. La profondeur radiale de la coupe effectuée par l'outil de coupe (3) doit juste suffire pour que les fentes de passage radiales (1) soient percées dans les régions prévues à cet effet, sans que les autres régions de la circonférence soient percées simultanément.A piston has passage slots in an annular groove which extend radially to the interior of the piston. These slots in the direction of the circumference of the corresponding annular groove are located exclusively in the regions on the pressure / counterpressure side of the piston, while the wall of the piston radially adjacent to the bottom of the groove present in the regions provided with slots a thickness less than that of the areas of the circumference not provided with slots. In order to easily obtain passage slots of exact dimensions, a stationary cutting tool (3) engages the annular groove (2) of a piston rotated about its longitudinal axis. The cutting tool removes material from the radially closed bottom of the annular groove (2), over the entire circumference thereof and over a height predetermined by the shape of the tool. The radial depth of the cut made by the cutting tool (3) should be just sufficient for the radial passage slots (1) to be drilled in the regions provided for this purpose, without the other regions of the circumference being drilled simultaneously .

Description

Verfahren zur Einarbeitung radialer Kolbenringnut-Schlitzdurchbrüche Process for incorporating radial piston ring groove slot openings
Die Erfindung betrifft ein Verfahren nach- dem Oberbe¬ griff des Patentanspruchs 1.The invention relates to a method according to the preamble of claim 1.
Radiale Schlitzdurchbrüche in der Kolbenringnut eines Kolbens wie er beispielsweise aus CH-Z "technica, 1980 H 25/26, Seite 2277 - 2313, Bild 12" bekannt ist haben in der Regel den Zweck, den Kolbenkopf in den auf der Druck- und Gegendruckseite des Kolbens lie¬ genden Bereichen von dem Schaft zu trennen. Sofern die Kolbenringnuten eines Tauchkolbens für Verbren¬ nungsmotoren ausschließlich im Kolbenkopf oberhalb des Schaftes angebracht sind, befinden sich die ge¬ nannten radialen Schlitzdurchbrüche in der untersten an den Kolbenschaft angrenzenden Ringnut. In diese Ringnut ist dann der Ölabstreifring eingelegt. Han¬ delt es sich bei den Ölringen um solche, die von ei¬ ner radial innen in dem Ölabstreifring angebrachten Schlauchfeder gespannt werden, so kann es bei Verwen¬ dung von Schlauchfedern mit geringem Wicklungsdurch¬ messer von z.B. weniger als 2 mm dazu kommen, daß die Schlauchfedern sich in den radialen Schlitzdurchbrü¬ chen verklemmen. Um dies sicher zu vermeiden, müssen die radialen Schlitzdurchbrüche mit einer geringeren Höhe als der Windungsdurchmesser der Schlauchfeder ausgeführt sein. Bei den bisherigen Herstellungsver¬ fahren ist eine sichere Einhaltung enger Toleranzen eines axial niedrigen Schlitzdurchbruches häufig nicht möglich. Das gilt vor allem für gegossene Kol¬ ben. Hierbei werden die Schlitzdurchbrüche dadurch erzeugt, daß in den Umfangsbereichen des Kolbens, in denen diese Durchbrüche zu liegen kommen, nämlich im Bereich der Druck- und Gegendruckseite des Kolbens, das Kolbengrundmaterial radial innerhalb des zu durchbrechenden Ringnutgrundes an dieser Stelle der¬ art gegossen wird, daß beim Einarbeiten der Nut dort ein Schlitz entsteht. In diesen Fällen lassen sich enge Toleranzen der Schlitzdurchbrüche nicht immer sicher einhalten.Radial slot openings in the piston ring groove of a piston such as is known, for example, from CH-Z "technica, 1980 H 25/26, pages 2277-2333, picture 12" generally have the purpose of pushing the piston head into the on the pressure and counter-pressure side to separate areas of the piston from the shaft. If the piston ring grooves of a plunger for internal combustion engines are fitted exclusively in the piston head above the shaft, the radial slot openings mentioned are located in the lowest ring groove adjacent to the piston shaft. The oil scraper ring is then inserted into this ring groove. If the oil rings are those that are tensioned by a hose spring attached radially on the inside in the oil scraper ring, the use of hose springs with a small winding diameter of, for example, less than 2 mm can result in the fact that the hose springs jam in the radial slot openings. To avoid this safely, the radial slot openings must be smaller Height as the winding diameter of the tube spring. In the previous manufacturing processes, it is often not possible to reliably adhere to narrow tolerances of an axially low slot opening. This applies above all to cast pistons. Here, the slot openings are produced in that in the circumferential areas of the piston in which these openings come to rest, namely in the region of the pressure and counterpressure side of the piston, the piston base material is poured radially inside the ring groove base to be broken through at this point, that a slot is created when the groove is worked in. In these cases, narrow tolerances of the slot openings cannot always be reliably observed.
Hiervon ausgehend liegt der Erfindung die Aufgabe zu¬ grunde, die erforderlichen Schlitzdurchbrüche mit hö¬ herer Genauigkeit auf möglichst wirtschaftliche Weise herzustellen.Proceeding from this, the invention is based on the object of producing the required slot openings with greater accuracy in the most economical way possible.
Gelöst wird diese Aufgabe durch ein Bearbeitungsver¬ fahren nach den kennzeichnenden- Merkmalen des Patent¬ anspruchs 1.This object is achieved by a processing method according to the characterizing features of patent claim 1.
Bei diesem Verfahren können die im Bereich der Druck- und Gegendruckseite des Kolbens einzubringenden Schlitzdurchbrüche auf einfachste Weise auf einer Drehmaschine mit einem Schneidwerkzeug äußerst exakt hergestellt werden. Ein Ausführungsbeispiel zeigt die Zeichnung, in der die Hälfte eines Kolbens im Schnitt dargestellt istWith this method, the slot openings to be made in the area of the pressure and counterpressure side of the piston can be produced extremely precisely on a lathe with a cutting tool. An embodiment is shown in the drawing, in which half of a piston is shown in section
Die Innenform des Kolbens ist fertig gegossen. In den Bereichen, in denen ein Schlitzdurchbruch 1 einzuar¬ beiten ist, ist das Kolbenmaterial radial innerhalb der Ringnut 2 in einer derart geringen Wanddicke aus¬ geführt, daß diese Wandbereiche von einem Schneid¬ werkzeug 3 bei rotierendem Kolben durchbrochen werden können. Das Schneidwerkzeug kann dabei so geformt sein, daß es die gesamte axiale Höhe der Ringnut 2 ausfüllt und lediglich an seinem vorderen Bereich ei¬ nen schmaleren höhenmäßig auf den zu erzeugenden Schlitzdurchbruch reduzierten Schneidansatz 4 be¬ sitzt. Mit der Länge des Schneidansatzes 4 werden einmal die Schlitzdurchbrüche 1 erzielt und zum ande¬ ren werden damit in den Umfangsbereichen, in denen keine vollständigen Durchbrüche erfolgen sollen, ent¬ sprechende schmale Ringnutfortsätze erzeugt. Diese schmalen Ringnutfortsätze haben in jenen Bereichen technisch keine Funktion und sie sind dort lediglich deshalb vorhanden, um den Kolben rotierend an dem Schneidwerkzeug 3 vorbeiführen- zu können.The inner shape of the piston is cast. In the areas in which a slot opening 1 is to be worked in, the piston material is carried out radially within the annular groove 2 with such a small wall thickness that these wall areas can be broken through by a cutting tool 3 with the piston rotating. The cutting tool can be shaped in such a way that it fills the entire axial height of the annular groove 2 and only has at its front region a narrower cutting attachment 4 which is reduced in height to the slot opening to be produced. With the length of the cutting attachment 4, the slot openings 1 are achieved on the one hand and, on the other hand, corresponding narrow annular groove extensions are produced in the peripheral areas in which no complete openings are to be made. These narrow annular groove extensions have no technical function in those areas and they are only there to be able to rotate the piston past the cutting tool 3.
Mit dem erfindungsgemäßen Verfahren können bei Kolben mit fertig gegossener Innenform Schlitzdurchbrüche mit axialen Höhen bis hinunter zu etwa 0,5 - 0,8 mm ganz exakt erzeugt werden. With the method according to the invention, slot breakthroughs with axial heights down to about 0.5-0.8 mm can be produced very precisely in pistons with a cast internal shape.

Claims

PatentanspruchClaim
Verfahren zur Einarbeitung radialer in den freien Kolbeninnenraum führender Schlitzdurchbrüche in eine Kolbenringnut eines Tauchkolbens für insbesondere Verbrennungsmotoren, bei dem sich diese Schlitzdurch¬ brüche in U fangsrichtung der jeweiligen Ringnut auf die in Druck- und Gegendruckseite des Kolbens liegen¬ den Bereiche beschränken und bei dem die an dem je¬ weiligen Nutgrund radial angrenzenden Kolbenmaterial¬ wanddicken in den durchbrochenen Bereichen geringer als in den nicht durchbrochenen Umfangsbereichen sind, dadurch gekennzeichnet, daß ein ortsfest gehaltenes Schneidwerkzeug (3) in die Ringnut (2) des um die Längsachse rotierenden Kolbens eingreift und dabei über eine durch die Form des Schneidwerkzeuges (3) in Richtung der Kolbenachse vorgebbare Höhe Material aus dem radial geschlossenen Grund dieser Ringnut (2) über den gesamten Umfang herausarbeitet, und zwar auf einer radialen Tiefe, die gerade ausreicht, um die radialen Schlitzdurch¬ brüche (1) in den dafür vorgesehenen Bereichen zu er¬ reichen, ohne gleichzeitiges Durchbrechen der übrigen Umfangsbereiche erfolgt, über die die an die Ober- und Unterflanke der Ringnut (2) angrenzenden Kolben¬ bereiche miteinander verbunden bleiben. Process for incorporating radial slot openings leading into the free piston interior into a piston ring groove of a plunger for in particular internal combustion engines, in which these slot openings are limited in the circumferential direction of the respective ring groove to the areas located in the pressure and counterpressure side of the piston and in which the on the respective groove base of radially adjacent piston material wall thicknesses in the perforated areas are smaller than in the non-perforated peripheral areas, characterized in that a stationary cutting tool (3) engages in the annular groove (2) of the piston rotating about the longitudinal axis and thereby Using a height that can be predetermined by the shape of the cutting tool (3) in the direction of the piston axis, material is worked out from the radially closed base of this annular groove (2) over the entire circumference, to a radial depth that is just sufficient to accommodate the radial slot openings (1) in the areas intended for this purpose are achieved without simultaneously breaking through the other peripheral areas via which the piston areas adjoining the upper and lower flanks of the annular groove (2) remain connected to one another.
EP89906020A 1988-07-13 1989-06-02 Process for machining radial through-slots in piston-ring grooves Withdrawn EP0425502A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3823687 1988-07-13
DE3823687A DE3823687C1 (en) 1988-07-13 1988-07-13

Publications (1)

Publication Number Publication Date
EP0425502A1 true EP0425502A1 (en) 1991-05-08

Family

ID=6358560

Family Applications (1)

Application Number Title Priority Date Filing Date
EP89906020A Withdrawn EP0425502A1 (en) 1988-07-13 1989-06-02 Process for machining radial through-slots in piston-ring grooves

Country Status (5)

Country Link
US (1) US5176051A (en)
EP (1) EP0425502A1 (en)
JP (1) JP2766014B2 (en)
DE (1) DE3823687C1 (en)
WO (1) WO1990000692A1 (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2735202B1 (en) * 1995-06-06 1997-08-22 Joint Francais SEALING DEVICE, HYDRAULIC BRAKING CIRCUIT COMPRISING SUCH A DEVICE AND METHOD FOR MANUFACTURING SUCH A DEVICE
KR20020087797A (en) * 2001-05-16 2002-11-23 에이.티.에프 주식회사 Manufacture method of the ornaments meterial with hot-adhesion form using thermosetting plastic resin
DE10322921A1 (en) * 2003-05-21 2004-12-16 Mahle Gmbh Method of manufacturing a one-piece piston for an internal combustion engine
CN112191864A (en) * 2020-09-29 2021-01-08 中国航发动力股份有限公司 Machining method for blade installation annular groove

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2967745A (en) * 1960-03-17 1961-01-10 Guy L Stevens Piston ring groove spacer
US3656766A (en) * 1969-12-15 1972-04-18 Robert Geffroy Piston and piston rings unit for an internal combustion engine
DE3213807A1 (en) * 1982-04-15 1983-10-27 Mahle Gmbh, 7000 Stuttgart Oil scraper piston ring
US4867020A (en) * 1986-10-31 1989-09-19 The Cross Company Apparatus for finishing pistons and the like and method therefor

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO9000692A1 *

Also Published As

Publication number Publication date
JPH04500480A (en) 1992-01-30
WO1990000692A1 (en) 1990-01-25
JP2766014B2 (en) 1998-06-18
DE3823687C1 (en) 1989-06-15
US5176051A (en) 1993-01-05

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