EP0708698B1 - Process for manufacturing pistons, piston rods, as well as cylinders for hydraulic or pneumatic units - Google Patents

Process for manufacturing pistons, piston rods, as well as cylinders for hydraulic or pneumatic units Download PDF

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Publication number
EP0708698B1
EP0708698B1 EP93914547A EP93914547A EP0708698B1 EP 0708698 B1 EP0708698 B1 EP 0708698B1 EP 93914547 A EP93914547 A EP 93914547A EP 93914547 A EP93914547 A EP 93914547A EP 0708698 B1 EP0708698 B1 EP 0708698B1
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EP
European Patent Office
Prior art keywords
grinding
fact
hard
hydraulic
piston rods
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Expired - Lifetime
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EP93914547A
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German (de)
French (fr)
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EP0708698A1 (en
Inventor
Günter Weber
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B33/00—Honing machines or devices; Accessories therefor
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B1/00—Processes of grinding or polishing; Use of auxiliary equipment in connection with such processes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B19/00—Single-purpose machines or devices for particular grinding operations not covered by any other main group
    • B24B19/08—Single-purpose machines or devices for particular grinding operations not covered by any other main group for grinding non-circular cross-sections, e.g. shafts of elliptical or polygonal cross-section
    • B24B19/10—Single-purpose machines or devices for particular grinding operations not covered by any other main group for grinding non-circular cross-sections, e.g. shafts of elliptical or polygonal cross-section for grinding pistons
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B24—GRINDING; POLISHING
    • B24B—MACHINES, DEVICES, OR PROCESSES FOR GRINDING OR POLISHING; DRESSING OR CONDITIONING OF ABRADING SURFACES; FEEDING OF GRINDING, POLISHING, OR LAPPING AGENTS
    • B24B21/00—Machines or devices using grinding or polishing belts; Accessories therefor
    • B24B21/02—Machines or devices using grinding or polishing belts; Accessories therefor for grinding rotationally symmetrical surfaces

Definitions

  • the invention relates to a method for producing pistons and piston rods and cylinders for hydraulic or pneumatic units.
  • the invention aims to provide a method that ensures a long service life of pistons or piston rods and cylinders for hydraulic or pneumatic units.
  • the process according to the invention is characterized in that a finely sized cylindrical semi-finished product made of an aluminum alloy is hard anodized on its sliding surface and that the hard anodized product rotates about its axis and the sliding surface layer formed is processed in several successive grinding operations with flat grinding media of different decreasing grain sizes, whereby the grinding operations are carried out until the dust development stops and the last grinding operation is polished until the flat grinding medium sticks.
  • the method according to the invention makes it possible to achieve a constant surface quality on a wide variety of starting surfaces, largely independently of the starting roughness.
  • a particularly long service life of the pistons and piston rods and cylinders results if the alloy AlMgSi 1 is used as the material for the semi-finished product and the anodization depth is 50 to 60 ⁇ m.
  • a cylindrical semifinished product made of the alloy AlMgSi 1 with a length of 500 mm and a diameter of just over 60 mm was clamped in a lathe and finely finished with a diamond knife to a diameter of 60 mm.
  • the finely sized semi-finished product was hard anodized on its surface 50 to 60 ⁇ m deep.
  • the hard anodized product was then clamped back into the lathe and rotated at 2500 rpm. Then five grinding operations were carried out with corundum sanding papers of the types (in this order) P 100, P 150, P 280, P 400 and P 999 (Rouge paper).
  • the type designation P 100 denotes an abrasive paper in which the sieve has 100 mesh / inch for its production.
  • Each sandpaper was mounted on a sanding block and was pressed by means of this with 50 N against the rotating product and moved along it in the axial direction. The first four sanding processes were carried out until the dust development ceased, and the last sanding process, which already corresponds to a fine polishing process, was carried out until the sanding paper stuck.
  • polishing paper instead of polishing paper, of course, any flat abrasive medium with the appropriate grit can be used.
  • the hydraulic cylinder piston rod with aluminum alloy core and surface layer produced in this way had an excellent sliding surface quality, which was easily comparable to that of hard chrome-plated piston rods.
  • the roughness depth of 0.3 ⁇ m achieved in this example is excellent for the sliding surface of a piston or a piston rod or a cylinder and does not damage the seals.
  • the method according to the invention can be carried out both by hand and by machine.
  • machine execution e.g. appropriately programmed NC machine tools equipped with grinding tools can be used.
  • Such machines can automatically carry out the necessary clamping movements and sanding paper changes.
  • the grinding parameters such as grinding pressure and duration can be controlled automatically depending on the measured values from the corresponding dust sensors.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Finish Polishing, Edge Sharpening, And Grinding By Specific Grinding Devices (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

A process is disclosed for manufacturing pistons and piston rods, as well as cylinder for hydraulic or pneumatic units. The sliding surface of a finely trimmed cylindrical semi-finished product made of an aluminium alloy is hard anodized, the thus hard anodized product is rotated around its axis and the thus formed ceramic sliding surface layer is machined in several successive grinding processes by flat grinding media having grains of different, decreasing sizes.

Description

Die Erfindung betrifft ein Verfahren zum Herstellen von Kolben und Kolbenstangen sowie Zylindern für Hydraulik- oder Pneumatikaggregate.The invention relates to a method for producing pistons and piston rods and cylinders for hydraulic or pneumatic units.

Es ist bekannt, Kolben für Hydraulik- oder Pneumatikzylinder durch Hartverchromung mit einer Chromschicht zu überziehen. Die Chrombeschichtung erweist sich aber als anfällig gegen Beschädigungen und führt in weiterer Folge zu Rostbildung und einem raschen Verschleiß der Kolben und Dichtungen. Es ist ferner bekannt, Aluminiumteile durch Anodisierung mit einer verschleißfesten Oberflächenschicht zu versehen.It is known to coat pistons for hydraulic or pneumatic cylinders with a chrome layer by hard chrome plating. However, the chrome coating proves to be susceptible to damage and subsequently leads to rust formation and rapid wear of the pistons and seals. It is also known to provide aluminum parts with a wear-resistant surface layer by anodization.

Die Erfindung zielt darauf ab, ein Verfahren zu schaffen, das eine hohe Lebensdauer von Kolben bzw. Kolbenstangen und Zylindern für Hydraulik- oder Pneumatikaggregate gewährleistet. Das erfindungsgemäße Verfahren zeichnet sich dadurch aus, daß ein feingeschlichtetes zylindrisches Halbzeug aus einer Aluminiumlegierung an seiner Gleitfläche hartanodisiert wird und daß das hartanodisierte Produkt um seine Achse in Drehung versetzt und die gebildete Gleitflächenschicht in mehreren aufeinanderfolgenden Schleifvorgängen mit flächigen Schleifmedien unterschiedlicher abnehmender Körnung bearbeitet wird, wobei die Schleifvorgänge jeweils bis zum Aufhören der Staubentwicklung durchgeführt werden und beim letzten Schleifvorgang bis zum Haftenbleiben des flächigen Schleifmediums poliert wird.The invention aims to provide a method that ensures a long service life of pistons or piston rods and cylinders for hydraulic or pneumatic units. The process according to the invention is characterized in that a finely sized cylindrical semi-finished product made of an aluminum alloy is hard anodized on its sliding surface and that the hard anodized product rotates about its axis and the sliding surface layer formed is processed in several successive grinding operations with flat grinding media of different decreasing grain sizes, whereby the grinding operations are carried out until the dust development stops and the last grinding operation is polished until the flat grinding medium sticks.

Bisher wurde das Hartanodisieren z.B. von Kolbenoberflächen als nicht zielführend angesehen, weil die entstehende Schicht mikroporös und entsprechend rauh ist, was einem Einsatz als Gleitoberfläche grundsätzlich widerspricht. Insbesondere bei Kolben und Kolbenstangen würde eine derart rauhe Oberfläche die Zylinderdichtungen beschädigen.So far, hard anodizing has been viewed as unsuitable by piston surfaces because the resulting layer is microporous and correspondingly rough, which fundamentally contradicts its use as a sliding surface. In the case of pistons and piston rods in particular, such a rough surface would damage the cylinder seals.

Wiederholt wurden Versuche unternommen, die Rauhheit der Schicht zu verringern, so z.B. durch Komprimieren und Verschließen der Poren in einem heißen Wasserbad oder durch Schleifen mittels Schleifpulver. Es gelang jedoch nicht, in die Nähe der für den Einsatz als Kolben bzw. Kolbenstange erforderlichen Oberflächengüte zu kommen.Attempts have been made repeatedly to reduce the roughness of the layer, for example by compressing and Seal the pores in a hot water bath or by grinding with grinding powder. However, it was not possible to get close to the surface quality required for use as a piston or piston rod.

Mit dem erfindungsgemäßen Verfahren ist es nun erstmals möglich, Kolben und Kolbenstangen sowie Zylinder aus einer Aluminiumlegierung mit einer Gleitfläche mit einer DIN-Rauhtiefe Rt von z.B. 0,3 µm herzustellen. Diese Gleitflächenglätte hält jede Gefahr einer Beschädigung der Dichtungen hintan und gewährleistet eine gegenüber den herkömmlichen verchromten Teilen wesentlich erhöhte Lebensdauer.With the method according to the invention, it is now possible for the first time to produce pistons and piston rods and cylinders from an aluminum alloy with a sliding surface with a DIN roughness depth R t of, for example, 0.3 μm. This sliding surface smoothness eliminates any risk of damage to the seals and ensures a significantly longer service life than conventional chrome-plated parts.

Das erfindungsgemäße Verfahren ermöglicht es bei verschiedensten Ausgangsoberflächen weitgehend unabhängig von der Ausgangsrauhigkeit eine gleichbleibende Oberflächenqualität zu erzielen.The method according to the invention makes it possible to achieve a constant surface quality on a wide variety of starting surfaces, largely independently of the starting roughness.

Es hat sich gezeigt, daß es besonders günstig ist, wenn fünf Schleifvorgänge mit Schleifpapieren der Typen P 100, P 150, P 280, P 400 und P 999 durchgeführt werden, wobei P 100 ein Schleifpapier kennzeichnet, bei dem das Sieb zu seiner Herstellung 100 Maschen/Zoll besitzt. Diese Werte sind optimiert, ein Abgehen von diesen Werten führt zu einer verschlechterten Oberflächengüte.It has been shown that it is particularly expedient if five sanding operations are carried out using types P 100, P 150, P 280, P 400 and P 999, where P 100 denotes an abrasive paper in which the screen is 100 for its manufacture Stitches / inches. These values are optimized, a departure from these values leads to a deteriorated surface quality.

Eine weitere Optimierung ergibt sich, wenn das hartanodisierte Produkt beim Schleifvorgang mit etwa 2500 U/min in Drehung versetzt und das Schleifmedium mit etwa 50 N angedrückt wird.A further optimization results if the hard anodized product is rotated at approximately 2500 rpm during the grinding process and the grinding medium is pressed on at approximately 50 N.

Eine besonders lange Lebensdauer der Kolben und Kolbenstangen sowie Zylinder ergibt sich, wenn als Werkstoff für das Halbzeug die Legierung AlMgSi 1 verwendet wird und die Anodisationstiefe 50 bis 60 µm beträgt.A particularly long service life of the pistons and piston rods and cylinders results if the alloy AlMgSi 1 is used as the material for the semi-finished product and the anodization depth is 50 to 60 µm.

Das erfindungsgemäße Verfahren wird nun an Hand eines Ausführungsbeispieles und einer dabei hergestellten Kolbenstange näher erläutert. Dabei wird auf die Figuren Bezug genommen, in denen zeigen:

  • Fig. 1 die mit einem Testgerät gemessene Oberflächenrauhigkeit einer Kolbenstangenoberfläche vor der Bearbeitung und
  • Fig. 2 die mit dem gleichen Testgerät gemessene Oberflächenrauhigkeit der Kolbenstangenoberfläche nach der erfindungsgemäßen Bearbeitung.
The method according to the invention will now be explained in more detail using an exemplary embodiment and a piston rod produced thereby. Reference is made to the figures in which:
  • Fig. 1 shows the surface roughness of a piston rod surface measured with a tester before machining and
  • 2 shows the surface roughness of the piston rod surface measured with the same test device after the machining according to the invention.

Ein zylinderförmiges Halbzeug aus der Legierung AlMgSi 1 mit einer Länge von 500 mm und einem Durchmesser von etwas über 60 mm wurde in eine Drehbank eingespannt und mit einem Diamantmesser auf einen Durchmesser von 60 mm feingeschlichtet.A cylindrical semifinished product made of the alloy AlMgSi 1 with a length of 500 mm and a diameter of just over 60 mm was clamped in a lathe and finely finished with a diamond knife to a diameter of 60 mm.

Das feingeschlichtete Halbzeug wurde an seiner Oberfläche 50 bis 60 µm tief hartanodisiert.The finely sized semi-finished product was hard anodized on its surface 50 to 60 µm deep.

Anschließend wurde das hartanodisierte Produkt wieder in die Drehbank eingespannt und mit 2500 U/min in Drehung versetzt. Sodann wurden fünf Schleifvorgänge mit Korund-Schleifpapieren der Typen (in dieser Reihenfolge) P 100, P 150, P 280, P 400 und P 999 (Rouge-Papier) durchgeführt. Die Typenbezeichnung P 100 kennzeichnet ein Schleifpapier, bei dem das Sieb zu seiner Herstellung 100 Maschen/Zoll besitzt.The hard anodized product was then clamped back into the lathe and rotated at 2500 rpm. Then five grinding operations were carried out with corundum sanding papers of the types (in this order) P 100, P 150, P 280, P 400 and P 999 (Rouge paper). The type designation P 100 denotes an abrasive paper in which the sieve has 100 mesh / inch for its production.

Jedes Schleifpapier war auf einem Schleifblock aufgezogen und wurde mittels diesem mit 50 N gegen das rotierende Produkt gedrückt und in axialer Richtung entlang diesem bewegt. Die ersten vier Schleifvorgänge wurden jeweils bis zum Aufhören der Staubentwicklung durchgeführt und der letzte Schleifvorgang, der bereits einem Feinpoliervorgang entspricht, wurde bis zum Haftenbleiben des Schleifpapieres durchgeführt.Each sandpaper was mounted on a sanding block and was pressed by means of this with 50 N against the rotating product and moved along it in the axial direction. The first four sanding processes were carried out until the dust development ceased, and the last sanding process, which already corresponds to a fine polishing process, was carried out until the sanding paper stuck.

Anstelle von Polierpapier kann selbstverständlich jedes flächige Schleifmedium mit der entsprechenden Körnung verwendet werden.Instead of polishing paper, of course, any flat abrasive medium with the appropriate grit can be used.

Die auf diese Weise hergestellte Hydraulikzylinder-Kolbenstange mit Aluminiumlegierungskern und Oberflächenschicht wies eine ausgezeichnete Gleitflächengüte auf, die ohne weiteres mit der von hartverchromten Kolbenstangen vergleichbar war.The hydraulic cylinder piston rod with aluminum alloy core and surface layer produced in this way had an excellent sliding surface quality, which was easily comparable to that of hard chrome-plated piston rods.

In den Fig. 1 und 2 ist das Rauhheitsprofil Y in µm über der Rauhheitsbezugsstrecke X in mm aufgetragen. Die gesamte Rauhheitsbezugsstrecke betrug 4 mm und war in fünf Abschnitte zu 0,8 mm unterteilt. Die rechnerische Analyse nach DIN-Norm ergab für den Profilverlauf nach Fig. 1 die DIN-Werte:

Mittenrauhwert Ra
0,4 µm
gemittelte Rauhtiefe Rz
2,5 µm
Rauhtiefe Rt
3,4 µm
1 and 2, the roughness profile Y is plotted in μm over the roughness reference distance X in mm. The total roughness reference distance was 4 mm and was divided into five 0.8 mm sections. The computational analysis according to the DIN standard gave the DIN values for the profile profile according to FIG. 1:
Average roughness value R a
0.4 µm
average roughness R z
2.5 µm
Roughing depth R t
3.4 µm

Die Analyse für den Profilverlauf nach Fig. 2 ergab die DIN-Werte:

Mittenrauhwert Ra
0,05 µm
gemittelte Rauhtiefe Rz
0,3 µm
Rauhtiefe Rt
0,3 µm
The analysis for the profile course according to FIG. 2 gave the DIN values:
Average roughness value R a
0.05 µm
average roughness R z
0.3 µm
Roughing depth R t
0.3 µm

Die in diesem Beispiel erzielte Rauhtiefe von 0,3 µm ist für die Gleitfläche eines Kolbens bzw. einer Kolbenstange oder eines Zylinders ausgezeichnet und beschädigt die Dichtungen nicht.The roughness depth of 0.3 µm achieved in this example is excellent for the sliding surface of a piston or a piston rod or a cylinder and does not damage the seals.

Es versteht sich, daß das erfindungsgemäße Verfahren sowohl von Hand als auch maschinell ausgeführt werden kann. Zur maschinellen Ausführung können z.B. entsprechend programmierte und mit Schleifwerkzeugen bestückte NC-Werkzeugmaschinen eingesetzt werden. Derartige Maschinen können selbsttätig die erforderlichen Einspannbewegungen und Schleifpapierwechsel durchführen. Die Schleifparameter wie Schleifdruck und -dauer können automatisch in Abhängigkeit von Meßwerten von entsprechenden Staubfühlern gesteuert werden.It is understood that the method according to the invention can be carried out both by hand and by machine. For machine execution e.g. appropriately programmed NC machine tools equipped with grinding tools can be used. Such machines can automatically carry out the necessary clamping movements and sanding paper changes. The grinding parameters such as grinding pressure and duration can be controlled automatically depending on the measured values from the corresponding dust sensors.

Claims (4)

  1. Method of making pistons and piston rods as well as cylinders for hydraulic or pneumatic apparatus, characterized by the fact, that a precision finished cylindrical semi-fabricated component made of an aluminum alloy is hard-anodized at its surface and that the hard-anodized component is rotated about its axis and that the resultant sliding surface thereof is treated by a plurality of successive grinding steps with two-dimensional grinding media of different decreasing particle size, whereby each grinding operation is carried out until dust-formation ends and whereby buffing takes place during the final grinding operation until adherence of the two-dimensional grinding medium.
  2. Method in accordance with claim 1, characterized by the fact that five grinding operations are conducted with P 100, P 150, P 280, P 400 and P 999 type grinding webs, P 100 being a grinding web made with a sieve of 100 meshes per inch.
  3. Method of claim 1 or 2, characterized by the fact that during the grinding operation the hard-anodized article is rotated at 2,500 rpm and that the grinding medium is pressed against it at about 50 N.
  4. Method in accordance with one of claims 1 to 3, characterized by the fact that the material used for making the semi-fabricated component is AlMgSi 1 alloy and that the depth of anodization is 50 - 60 µm.
EP93914547A 1993-07-14 1993-07-14 Process for manufacturing pistons, piston rods, as well as cylinders for hydraulic or pneumatic units Expired - Lifetime EP0708698B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AT93914547T ATE158973T1 (en) 1993-07-14 1993-07-14 METHOD FOR PRODUCING PISTONS AND PISTON RODS AS WELL AS CYLINDERS FOR HYDRAULIC OR PNEUMATIC UNITS

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/AT1993/000119 WO1995002486A1 (en) 1993-07-14 1993-07-14 Process for manufacturing pistons, piston rods, as well as cylinders for hydraulic or pneumatic units

Publications (2)

Publication Number Publication Date
EP0708698A1 EP0708698A1 (en) 1996-05-01
EP0708698B1 true EP0708698B1 (en) 1997-10-08

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EP93914547A Expired - Lifetime EP0708698B1 (en) 1993-07-14 1993-07-14 Process for manufacturing pistons, piston rods, as well as cylinders for hydraulic or pneumatic units

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US (1) US5842911A (en)
EP (1) EP0708698B1 (en)
JP (1) JPH09500062A (en)
DE (1) DE59307522D1 (en)
WO (1) WO1995002486A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009027647A1 (en) 2009-07-13 2011-01-20 Federal-Mogul Nürnberg GmbH Method and device for machining a piston for an internal combustion engine

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Publication number Priority date Publication date Assignee Title
FR2764225B1 (en) * 1997-06-05 1999-07-23 Uranie International METAL PART HAVING AN EXTERNAL SURFACE PRESENTING A PARTICULAR PROFILE, POLISHING PROCESS FOR ITS REALIZATION AND DEVICE FOR IMPLEMENTING THE PROCESS
US8690128B1 (en) 2008-07-23 2014-04-08 Lippert Components Manufacturing, Inc. Hydraulic leveling cylinder
US9073516B2 (en) * 2009-01-22 2015-07-07 Lippert Components Manufacturing Inc. Leveling jack for vehicle
CN105269250A (en) * 2014-07-20 2016-01-27 安庆市亿豪工贸发展有限公司 Machining process for rod end of hydraulic piston rod
JP6222571B2 (en) * 2014-09-12 2017-11-01 Smc株式会社 Fluid pressure cylinder
CN104985490B (en) * 2015-06-05 2017-05-10 东莞市依诺电子科技有限公司 Wiredrawing machining method for hard aluminum alloy base materials
USD813108S1 (en) * 2016-06-14 2018-03-20 Ningbo Zhongtian Hande Hydraulic Co., Ltd. Supporting cylinder for caravan

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DE2159551C3 (en) * 1971-12-01 1980-07-31 Julius & August Erbsloeh Gmbh + Co, 5600 Wuppertal Use of etching, grinding and blasting processes to produce matt areas on anodized aluminum surfaces
DE3344004C2 (en) * 1983-12-06 1987-05-07 Leonhard 8500 Nürnberg Baur Grinding and polishing processes
US4599827A (en) * 1985-06-24 1986-07-15 The United States Of America As Represented By The Secretary Of The Army Metallographic preparation of particulate filled aluminum metal matrix composite material
DE3636853A1 (en) * 1985-10-30 1987-05-07 Mazda Motor SIDE HOUSING FOR A ROTARY PISTON MOTOR AND METHOD FOR THE PRODUCTION THEREOF
JPH08155747A (en) * 1994-12-05 1996-06-18 Fuji Oozx Inc Working method for umbrella type workpiece
DE19513254A1 (en) * 1995-04-07 1996-10-10 Schaeffler Waelzlager Kg Machine part

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102009027647A1 (en) 2009-07-13 2011-01-20 Federal-Mogul Nürnberg GmbH Method and device for machining a piston for an internal combustion engine
WO2011006753A1 (en) 2009-07-13 2011-01-20 Federal-Mogul Nürnberg GmbH Method and device for machining a piston for an internal combustion engine

Also Published As

Publication number Publication date
US5842911A (en) 1998-12-01
WO1995002486A1 (en) 1995-01-26
DE59307522D1 (en) 1997-11-13
JPH09500062A (en) 1997-01-07
EP0708698A1 (en) 1996-05-01

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