GB2260790A - Making bearings - Google Patents
Making bearings Download PDFInfo
- Publication number
- GB2260790A GB2260790A GB9222034A GB9222034A GB2260790A GB 2260790 A GB2260790 A GB 2260790A GB 9222034 A GB9222034 A GB 9222034A GB 9222034 A GB9222034 A GB 9222034A GB 2260790 A GB2260790 A GB 2260790A
- Authority
- GB
- United Kingdom
- Prior art keywords
- cavities
- bearing surface
- metal bearing
- overlay
- selected portions
- 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.)
- Granted
Links
- 238000003754 machining Methods 0.000 claims abstract description 13
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 10
- 230000000873 masking effect Effects 0.000 claims abstract description 9
- 239000002184 metal Substances 0.000 claims abstract description 9
- 229910052751 metal Inorganic materials 0.000 claims abstract description 9
- 239000000126 substance Substances 0.000 claims abstract description 9
- 239000000463 material Substances 0.000 claims abstract description 8
- 238000007747 plating Methods 0.000 claims abstract description 8
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 5
- 229910001128 Sn alloy Inorganic materials 0.000 claims abstract description 4
- 229910000881 Cu alloy Inorganic materials 0.000 claims abstract description 3
- 238000009713 electroplating Methods 0.000 claims abstract description 3
- 239000011229 interlayer Substances 0.000 claims abstract description 3
- 230000003628 erosive effect Effects 0.000 claims description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 11
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 8
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 235000010344 sodium nitrate Nutrition 0.000 description 5
- 239000004317 sodium nitrate Substances 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 239000011780 sodium chloride Substances 0.000 description 4
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- 239000010410 layer Substances 0.000 description 2
- 238000005480 shot peening Methods 0.000 description 2
- 239000010409 thin film Substances 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- YVIMHTIMVIIXBQ-UHFFFAOYSA-N [SnH3][Al] Chemical compound [SnH3][Al] YVIMHTIMVIIXBQ-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000002313 adhesive film Substances 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005530 etching Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052745 lead Inorganic materials 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000003801 milling Methods 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000003472 neutralizing effect Effects 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 239000002344 surface layer Substances 0.000 description 1
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
- F16C33/02—Parts of sliding-contact bearings
- F16C33/04—Brasses; Bushes; Linings
- F16C33/24—Brasses; Bushes; Linings with different areas of the sliding surface consisting of different materials
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D7/00—Electroplating characterised by the article coated
- C25D7/10—Bearings
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Mechanical Engineering (AREA)
- Chemically Coating (AREA)
Abstract
A metal bearing surface is masked with a masking medium to expose only selected portions of the surface and the selected portions are treated by chemical machining to develop cavities thereat. This is followed by selectively electroplating said portions with an overlay material to at least fill said cavities, followed by removal of the masking medium. An initial plating treatment may be employed to apply an interlayer of nickel prior to applying an overlay of lead/tin/ copper alloy.
Description
ImDrovements in and relating to bearings
This invention relates to bearings and in particular to bearings incorporating a metal lining which constitutes the working surface of the bearing.
One problem of such bearings is their relatively poor resistance to seizure in certain circumstances such as a lack of lubricant.
Various proposals have been made for alleviating this, one being to subject the bearing surface to attrition, for example by shot peening, followed by electroplating with a relatively soft overlay, to fill the cavities created by the shot peening treatment. Whilst this is effective, it has the major disadvantage of requiring that the final plated bearing surface be machined to generate the appropriate surface geometry. This is serious, because the required degree of accuracy is extremely high; re-machining is not a trivial operation.
It is an object of the present invention to avoid the need for re-machining after plating with soft overlay.
According to this invention, a metal bearing surface is masked with a masking medium to expose only selected portions of the surface and the selected portions are treated by chemical machining to develop cavities thereat, followed by selectively plating said selected portions with an overlay material to at least fill said cavities, followed by removal of the masking medium.
The chemical machining treatment applied to develop the cavities in selected portions of the surface is preferably chemical erosion, for example by acidic, alkaline or electrolytic action.
Typical etching or chemical machining solutions which may be particularly suitable according to the composition of the surface to be treated include (i) sodium nitrate (ii) sodium nitrate and sodium chloride (iii) sodium chloride and (iv) a chemical milling composition based on sodium hydroxide and sodium nitrate. In the case of (i), a 2-3 molar solution at 500C may be used, the bearing being subjected to agitation in the solution at a frequency of the order of 120 cycles/minute with an amplitude in the range of 0.5 to 1 cm. Typical current flows of 20 to 100
A/cm2 would be used.
In the case of (ii) a typical solution would be 2-3 molar sodium nitrate and 0.5 molar sodium chloride, the other processing conditions being the same.
In the case of (iii) a 0.2 to 0.5 molar solution of sodium chloride may be used at around 80"C, with an applied DC current of 1 A/cm2 together with superimposed AC current of 0.4 A/cm2. In the case of (iv) a typical solution might comprise sodium hydroxide in an amount of 60-100 g/litre, sodium nitrate 50-80 g/l, and ethylene glycol 100 ml/l, the mix being used at 75-950C.
Precise concentrations and operating conditions may be further optimised by experiment, since they will vary according to the composition of the bearing to be treated.
The cavities generated may be between 5 and 75 microns deep, and are preferably between 15 and 45 microns deep, a depth of 20-30 microns being typical. The selected portions of the surface which are to be eroded may be defined by applying a chemically resistant masking medium, for example by a printing technique, or as an adhesive film. In this way, the size, shape and disposition of the cavities can be varied within wide limits.
In fact, the disposition/distribution pattern of the cavities can be made such that the pattern constitutes an identification mark such as a logo, trademark, name or part number, if so desired.
The selective plating step may apply any of the commonly employed overlay materials; it may include the application of an interlayer of for example nickel, where this is considered beneficial to the endurance of the overlay, which may be for example, a lead/tin/copper alloy.
Whilst the plating operation may be carried out to precisely fill the cavities, it is within the scope of the invention to overfill the cavities to leave some overlay material above the bearing surface. Whilst this may need some subsequent surface machining, the bearing has not been subjected to any treatment likely to develop distortion of the originally machined surface.
Accordingly such subsequent machining does not have to include a precision boring operation.
In order that the invention be better understood, a preferred embodiment of it will now be described by way of example. A half bearing shell was produced by pressing and coining a blank comprising a steel backing layer and a bearing surface layer of
Al Sn20 Cul aluminium-tin alloy. A masking medium in the form of a thin film resist material formed with a pattern of holes was applied to the bearing surface so that the only parts of the surface which were exposed were those at the locations of the holes. A chemical machining treatment of the kind described earlier under (iii) was then applied to develop cavities on the order of 25 microns deep at the hole locations. After rinsing and neutralising the etchant, the chemically machined half bearing shell was then given a nickel plating treatment to generate a nickel layer 0.002 - 0.004 mm thick.After a heat treatment this was followed by plating with an overlay comprising
Pb SuX6 Cu2 to completely fill the cavities with overlay. The thin film resist masking medium was then removed with solvent.
The resultant bearing required no further machining treatment; the precise arrangement of the cavities was readily visible as a surface pattern.
As an ancillary benefit of the invention, the surface pattern proved useful as a means of monitoring the extent of wear of the bearing surface. The cavities were of known depth, and accordingly, when the extent of wear exceeded about 25 microns in any area, the pattern began to disappear. This was easier to detect by simple observation then wear assessment by more conventional means such as precision measurement. In particular, it was possible to see at a glance whether there was localised wear.
An important benefit of the invention is that chemical machining does not significantly alter the bearing geometry, so that the final product does not require the finish machining operation normally required, although there is no reason why such an operation cannot be carried out, if required by a particular application.
Claims (6)
1. A metal bearing surface having an overlay material thereon
applied by the steps of masking said surface to expose only
selected portions thereof, treating said selected portions
by chemical machining to develop cavities thereat, followed
by selectively electroplating said selected portions with
an overlay material to at least fill said cavities,
followed by removal of the masking medium.
2. A metal bearing surface according to claim 1 wherein the
cavities are developed by chemical erosion.
3. A metal bearing surface according to any preceding claim
wherein an initial plating treatment is employed to apply
an inter layer of nickel prior to applying the overlay
material.
4. A metal bearing surface according to any of claims 1-3
wherein the cavities are from 5-75 microns deep.
5. A metal bearing surface according to any of claims 1-3
wherein the cavities are from 15-45 microns deep.
6. A metal bearing surface according to any of claims 1-5
wherein the overlay is a lead/tin/copper alloy.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB919122509A GB9122509D0 (en) | 1991-10-23 | 1991-10-23 | Improvements in and relating to bearings |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9222034D0 GB9222034D0 (en) | 1992-12-02 |
| GB2260790A true GB2260790A (en) | 1993-04-28 |
| GB2260790B GB2260790B (en) | 1995-04-05 |
Family
ID=10703416
Family Applications (2)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB919122509A Pending GB9122509D0 (en) | 1991-10-23 | 1991-10-23 | Improvements in and relating to bearings |
| GB9222034A Expired - Fee Related GB2260790B (en) | 1991-10-23 | 1992-10-20 | Improvements in and relating to bearings |
Family Applications Before (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB919122509A Pending GB9122509D0 (en) | 1991-10-23 | 1991-10-23 | Improvements in and relating to bearings |
Country Status (1)
| Country | Link |
|---|---|
| GB (2) | GB9122509D0 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997003298A1 (en) * | 1995-07-12 | 1997-01-30 | Miba Gleitlager Aktiengesellschaft | Process for producing a sliding bearing |
| GB2338715A (en) * | 1998-06-24 | 1999-12-29 | Hang Fung Jewellery Co Ltd | Electrilytic deposition of metal int grooves |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB592464A (en) * | 1944-05-13 | 1947-09-18 | Sulzer Ag | A method of treating the running surfaces of machine parts to improve lubrication |
| GB633072A (en) * | 1947-10-09 | 1949-12-12 | Monochrome Ltd | Improvements in or relating to the treatment of metallic bearing surfaces |
-
1991
- 1991-10-23 GB GB919122509A patent/GB9122509D0/en active Pending
-
1992
- 1992-10-20 GB GB9222034A patent/GB2260790B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB592464A (en) * | 1944-05-13 | 1947-09-18 | Sulzer Ag | A method of treating the running surfaces of machine parts to improve lubrication |
| GB633072A (en) * | 1947-10-09 | 1949-12-12 | Monochrome Ltd | Improvements in or relating to the treatment of metallic bearing surfaces |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1997003298A1 (en) * | 1995-07-12 | 1997-01-30 | Miba Gleitlager Aktiengesellschaft | Process for producing a sliding bearing |
| GB2338715A (en) * | 1998-06-24 | 1999-12-29 | Hang Fung Jewellery Co Ltd | Electrilytic deposition of metal int grooves |
| GB2338715B (en) * | 1998-06-24 | 2003-03-19 | Hang Fung Jewellery Co Ltd | A method of depositing a metal on an article |
Also Published As
| Publication number | Publication date |
|---|---|
| GB9222034D0 (en) | 1992-12-02 |
| GB2260790B (en) | 1995-04-05 |
| GB9122509D0 (en) | 1991-12-04 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20081020 |