WO1997045226A1 - Method of electrochemically machining a raceway of a bearing ring and a bearing ring comprising said bearing ring - Google Patents

Method of electrochemically machining a raceway of a bearing ring and a bearing ring comprising said bearing ring Download PDF

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Publication number
WO1997045226A1
WO1997045226A1 PCT/NL1997/000306 NL9700306W WO9745226A1 WO 1997045226 A1 WO1997045226 A1 WO 1997045226A1 NL 9700306 W NL9700306 W NL 9700306W WO 9745226 A1 WO9745226 A1 WO 9745226A1
Authority
WO
WIPO (PCT)
Prior art keywords
raceway
bearing ring
groove
bearing
electrode
Prior art date
Application number
PCT/NL1997/000306
Other languages
French (fr)
Inventor
Hervé GIRARDIN
Frank Peter Wardle
Original Assignee
Skf Industrial Trading & Development Company B.V.
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 Skf Industrial Trading & Development Company B.V. filed Critical Skf Industrial Trading & Development Company B.V.
Publication of WO1997045226A1 publication Critical patent/WO1997045226A1/en

Links

Classifications

    • 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
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/58—Raceways; Race rings
    • F16C33/64—Special methods of manufacture
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H3/00—Electrochemical machining, i.e. removing metal by passing current between an electrode and a workpiece in the presence of an electrolyte
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23H—WORKING OF METAL BY THE ACTION OF A HIGH CONCENTRATION OF ELECTRIC CURRENT ON A WORKPIECE USING AN ELECTRODE WHICH TAKES THE PLACE OF A TOOL; SUCH WORKING COMBINED WITH OTHER FORMS OF WORKING OF METAL
    • B23H9/00—Machining specially adapted for treating particular metal objects or for obtaining special effects or results on metal objects
    • 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
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C19/00—Bearings with rolling contact, for exclusively rotary movement
    • F16C19/02—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows
    • F16C19/04—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly
    • F16C19/06—Bearings with rolling contact, for exclusively rotary movement with bearing balls essentially of the same size in one or more circular rows for radial load mainly with a single row or balls

Definitions

  • the present invention relates to a method of manufacturing a bearing ring for a bearing, whereby a groove to be serving as a raceway is formed which is subsequently electrochemically machined by passing a current across a narrow gap between said raceway and an electrode means, supplying electrolyte to the gap in a direction substantially tangential to the raceway, rotating the bearing ring around the central axis of the raceway and removing material from the raceway surface facing said electrode.
  • Such a method is known from the Dutch patent application 91.01379.
  • a method is described for electrochemical machining of a raceway of a bearing ring using a ball or slice thereof as the electrode, the raceway being manufactured by conventional mechanical machining.
  • Bearing rings having raceways manufactured according to this method show a quite satisfactory performance.
  • the object of the present invention is to provide a fast, cheap and simple method of manufacturing bearing rings without compromising their performance.
  • the method according to the invention is characterized in that the groove is formed by honing before being subjected to electrochemical machining
  • the groove of the bearing ring formed by honing is subsequently electrochemically machined using an electrode with a width tangential relative to the axis of rotation adapted to each particular circumferentially extending area such that the radius of curvature of the groove is kept constant .
  • the present invention also relates to a bearing comprising a bearing ring wherein the bearing ring is electrochemically machined according to the invention.
  • Fig. 1 is a schematic cross-section showing an electrode and a bearing ring to be machined.
  • Fig. 2 represents a cross-section along line II-II in fig. 1.
  • Fig. 1 shows a bearing ring 1 comprising a groove 2 constituting the raceway of the bearing ring 1.
  • the groove 2 is formed by honing.
  • An electrode 3 has a curved electrode surface 4 facing the groove 2, the curved electrode surface 4 and groove 2 being separated by a narrow gap 5 of, for example, 200 ⁇ m.
  • the radius of curvature of the curved electrode surface 4 is the same as the radius of curvature of the groove 2.
  • Electrolyte such as a sodium nitrate solution, is supplied to the gap 5 in a direction substantially tangential to the surface of the groove 2.
  • the bearing ring 1 is rotated around an axis 6 which axis coincides with the central axis of the raceway.
  • a current is passed across the narrow gap 5 to electrochemically machine the groove 2.
  • Electrochemical machining not only increases the groove depth but also the groove radius (dotted line) . This increases the tolerance range and hence make matching of bearing rings and rotating bodies more difficult.
  • the raceway which is formed by honing said raceway being composed of a plurality of narrow circumferentially extending coaxial areas, is subsequently electrochemically machined using an electrode 3 with a width tangential relative to the axis of rotation adapted to each particular circumferentially extending area of the raceway, such that the radius of the raceway is kept constant .
  • a convex electrode cross-section as shown in fig. 2 it is possible to increase the groove 2 but maintain a constant radius (broken line) .
  • the cross-section may be biconvex as well.
  • an electrode 3 comprising several electrode segments, the current through each segment being carefully adjusted to maintain the groove radius, can be used.
  • radius of curvature is intended to mean the desired profile of the groove 2 which is to be maintained.

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
  • Rolling Contact Bearings (AREA)

Abstract

The invention relates to a method of manufacturing a bearing ring, wherein the bearing ring is rotated around an axis coinciding with the axis of the raceway and the raceway is formed by honing before being subjected to electrochemical machining. Thus with only two operations bearing rings can be manufactured for bearings with excellent life span and properties.

Description

Method of electrochemically machining a raceway of a bearing ring and a bearing ring comprising said bearing ring
The present invention relates to a method of manufacturing a bearing ring for a bearing, whereby a groove to be serving as a raceway is formed which is subsequently electrochemically machined by passing a current across a narrow gap between said raceway and an electrode means, supplying electrolyte to the gap in a direction substantially tangential to the raceway, rotating the bearing ring around the central axis of the raceway and removing material from the raceway surface facing said electrode. Such a method is known from the Dutch patent application 91.01379. In this publication a method is described for electrochemical machining of a raceway of a bearing ring using a ball or slice thereof as the electrode, the raceway being manufactured by conventional mechanical machining. Bearing rings having raceways manufactured according to this method, show a quite satisfactory performance.
The object of the present invention is to provide a fast, cheap and simple method of manufacturing bearing rings without compromising their performance.
To this end, the method according to the invention is characterized in that the groove is formed by honing before being subjected to electrochemical machining
Surprisingly it has been found that when the groove constituting the raceway is manufactured by honing and subsequently subjected to electrochemical machining, a bearing ring with a raceway with an equally satisfactory performance is obtained whereas only two machining operations are required. According to a preferred embodiment the groove of the bearing ring formed by honing, said raceway being composed of a plurality of narrow circumferentially extending coaxial areas, is subsequently electrochemically machined using an electrode with a width tangential relative to the axis of rotation adapted to each particular circumferentially extending area such that the radius of curvature of the groove is kept constant .
This results in a bearing ring with superior characteristics with respect to waviness, smoothness and radius of curvature, allowing the manufacture of bearings of unprecedented quality.
Thus, the present invention also relates to a bearing comprising a bearing ring wherein the bearing ring is electrochemically machined according to the invention.
The invention will now be illustrated by means of the drawing in which
Fig. 1 is a schematic cross-section showing an electrode and a bearing ring to be machined.
Fig. 2 represents a cross-section along line II-II in fig. 1. Fig. 1 shows a bearing ring 1 comprising a groove 2 constituting the raceway of the bearing ring 1. The groove 2 is formed by honing. An electrode 3 has a curved electrode surface 4 facing the groove 2, the curved electrode surface 4 and groove 2 being separated by a narrow gap 5 of, for example, 200 μm. The radius of curvature of the curved electrode surface 4 is the same as the radius of curvature of the groove 2. Electrolyte, such as a sodium nitrate solution, is supplied to the gap 5 in a direction substantially tangential to the surface of the groove 2. The bearing ring 1 is rotated around an axis 6 which axis coincides with the central axis of the raceway. A current is passed across the narrow gap 5 to electrochemically machine the groove 2.
Electrochemical machining not only increases the groove depth but also the groove radius (dotted line) . This increases the tolerance range and hence make matching of bearing rings and rotating bodies more difficult. According to a preferred embodiment the raceway which is formed by honing, said raceway being composed of a plurality of narrow circumferentially extending coaxial areas, is subsequently electrochemically machined using an electrode 3 with a width tangential relative to the axis of rotation adapted to each particular circumferentially extending area of the raceway, such that the radius of the raceway is kept constant . Thus with a convex electrode cross-section as shown in fig. 2 it is possible to increase the groove 2 but maintain a constant radius (broken line) .
A person skilled in the art can easily determine the exact shape of the electrode required. For example, if too much material is removed from the axial ends of the groove, the corresponding widths of the electrode 3 are too large and should be reduced. Instead of an electrode 3 with a convex cross-section, the cross-section may be biconvex as well.
Alternatively an electrode 3 comprising several electrode segments, the current through each segment being carefully adjusted to maintain the groove radius, can be used.
In the present application the term "radius of curvature" is intended to mean the desired profile of the groove 2 which is to be maintained.

Claims

1. Method of manufacturing a bearing ring for a bearing, whereby a groove to be serving as a raceway is formed which is subsequently electrochemically machined by passing a current across a narrow gap between said raceway and an elec- trode means, supplying electrolyte to the gap in a direction substantially tangential to the raceway, rotating the bearing ring around the central axis of the raceway and removing material from the raceway surface facing said electrode, characterized in that the groove (2) is formed by honing before being subjected to electrochemical machining.
2. Method according to claim 1, characterized in that the raceway which is formed by honing, said raceway being composed of a plurality of narrow circumferentially extending coaxial areas, is subsequently electrochemically machined using an electrode with a width tangential relative to the axis of rotation adapted to each particular circumferentially extending area of the raceway, such that the radius of the raceway is kept constant.
3. Bearing comprising a bearing ring, characterized in that the bearing ring (1) is manufactured according to claim 1 or 2.
PCT/NL1997/000306 1996-05-30 1997-05-30 Method of electrochemically machining a raceway of a bearing ring and a bearing ring comprising said bearing ring WO1997045226A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NL1003232 1996-05-30
NL1003232A NL1003232C2 (en) 1996-05-30 1996-05-30 A method for manufacturing a bearing ring and a bearing comprising such a bearing ring.

Publications (1)

Publication Number Publication Date
WO1997045226A1 true WO1997045226A1 (en) 1997-12-04

Family

ID=19762941

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/NL1997/000306 WO1997045226A1 (en) 1996-05-30 1997-05-30 Method of electrochemically machining a raceway of a bearing ring and a bearing ring comprising said bearing ring

Country Status (2)

Country Link
NL (1) NL1003232C2 (en)
WO (1) WO1997045226A1 (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1812312A1 (en) * 1967-12-15 1970-02-26 Karl Marx Stadt Tech Hochschul Methods and tools for external cylindrical machining, especially by electrolytic grinding
NL9101379A (en) * 1991-08-13 1993-03-01 Skf Ind Trading & Dev METHOD AND APPARATUS FOR ELECTRO-CHEMICAL PROCESSING, FOR EXAMPLE POLISHING, OF A SURFACE OF AN ARTICLE.

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1812312A1 (en) * 1967-12-15 1970-02-26 Karl Marx Stadt Tech Hochschul Methods and tools for external cylindrical machining, especially by electrolytic grinding
NL9101379A (en) * 1991-08-13 1993-03-01 Skf Ind Trading & Dev METHOD AND APPARATUS FOR ELECTRO-CHEMICAL PROCESSING, FOR EXAMPLE POLISHING, OF A SURFACE OF AN ARTICLE.

Also Published As

Publication number Publication date
NL1003232C2 (en) 1997-12-03

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