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
  • F16C33/06—Sliding surface mainly made of metal
  • F16C33/12—Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing
• • 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
  • F16C2204/00—Metallic materials; Alloys
  • F16C2204/60—Ferrous alloys, e.g. steel alloys
• • 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
  • Y10T29/00—Metal working
  • Y10T29/46—Burning in, wearing in, or oil burnishing

Definitions

• ABSTRACT A process for forming relatively moving metal parts with matching surfaces by preparing at least one part from porous sintered iron, impregnating the pores of the sintered iron part with oleic acid containing an inhibitor selected from Tenemene, BHA, Bl-IT, or MTBHQ in an amount effective to inhibit the reaction between the iron and oleic acid at room temperature and subsequently bringing the parts into sliding contact until the heat developed at points of local high friction is sufficient to effect the reaction ,between iron and oleic acid.
• an inhibitor selected from Tenemene, BHA, Bl-IT, or MTBHQ in an amount effective to inhibit the reaction between the iron and oleic acid at room temperature and subsequently bringing the parts into sliding contact until the heat developed at points of local high friction is sufficient to effect the reaction ,between iron and oleic acid.
• a formed, porous sintered iron article with inhibited oleic acid in its pores is also disclosed.
• Sintered iron parts are frequently used in sliding contact with other metal pieces in uses where it is necessary for the relatively moving surfaces to be matched very closely. Even though powder metallurgy techniques can form pieces to very close tolerances, perfectly matching surfaces are difficult to obtain by the technique.
• the technique is difficult to use because oleic acid-impregnated sintered iron parts cannot be stored and because it is necessary to have impregnating equipment and machining equipment in close proximity to one another. It is also difficult to incorporate such close timing into an ordinary industrial process.
• This invention provides a process that avoids the problems set forth above.
• This invention is a process for forming matching surfaces between metal parts to be in sliding contact by making at least one of the parts of sintered iron, impregnating the pores of that part with oleic acid which contains Tenemene, BHA, BHT, or MTBHQ in an amount effective to inhibit the reaction between iron and oleic acid at room temperature, and then bringing the parts into sliding contact until the heat generated by friction raises the temperature of local high friction points to one at which iron and oleic acid will react.
• the invention also is a formed sintered iron article that has its pores impregnated with oleic acid containing an inhibitor selected from Tenemene, BHA, BHT, and MTBHQ in an amount effective to inhibit the reaction between iron and oleic acid.
• an inhibitor selected from Tenemene, BHA, BHT, and MTBHQ in an amount effective to inhibit the reaction between iron and oleic acid.
• Amounts of inhibitor in excess of 0.05%w are effective to inhibit the reaction and amounts in excess of 5.0%w have small incremental effect. Accordingly, it is preferred that the inhibitor be present in very small amounts, in excess of about 0.05%wandpreferably in excess of about 0.1%w, but that amounts in excess of It is presently thought that the sintered iron part im-.
• pregnated with inhibited oleic acid is stable chemically as long as the temperature is room temperature. Chemically stable means that oleic acid and iron do not react at a significant rate.
• the impregnated part is brought into sliding contact, those portions of the contacting surface that do not match the other surface are subjected to intense friction over a very local area. The heat from this friction raises the temperature above that at which the inhibitor is effective to retard or prevent the reaction between iron and oleic acid, and as a result the iron in the area of local high friction reacts rapidly with the oleic acid impregnated in the pores to form soft, amorphous iron oleate which is washed away with lubricant or worn away but, in any event, is disposed of benignly.
• Tenemene is N,Nbis (1,4-dimethyl pentyl)-pphenylene diamine
• BI-IA is t-butyl hydroxy anisol
• BHT is t-butyl hydroxy toluene
• MTBl-IQ is mono-t-butyl hydroquinone.
• the present invention was employed in the manufac-. ture of rocker arm balls for use in internal combustion engines.
• the rocker arm balls function in sliding contact with a socket-like metal receptacle. In use it is essential that the surface of the rocker arm ball be well matched to the surface of the receptacle.
• the rocker arm balls were made from a material that was 98.7%w iron, 0.18%w carbon, and the remainder miscellaneous materials including silicon, phosphorus, sulfur and oxygen.
• the material was in the form of a fine powder having a particle size distribution on a weight basis as follows:
• This material was uniformly blended with 0.75%w graphite and 0.75%w of a wax lubricant, the percentages being based on the weight of powdered metal.
• the blended powder was then pressed into the form of rocker arm balls until it had a nominal density of 6.0 g/cc, at which density it had sufficient green strength to be handled.
• the parts were then heated to about 2,000F in an inert gas atmosphere at which temperature a sintered metal structure was formed.
• the sintered metal structure was cooled in the oven to about 1,550F after which it was quenched in a conventional quench oil. At this point the sintered iron piece had approximately the same dimensions and same density as the green form.
• the quenched rocker arm balls were cleaned by a technique which provided available pore volume for the subsequent impregnation with inhibited oleic acid.
• the balls thus prepared were divided and some of them were immersed in oleic acid, while others were immersed in oleic acid containing various amounts of various inhibitors.
• the total pore volume of the balls was such that a maximum of 0.4 grams of impregnant, consisting of quench oil and oleic acid, could be taken up per ball. In all cases of balls prepared as described above, about 44%w of the maximum impregnant was taken up as oleic acid.
• the acid impregnated balls were exposed to open air at room temperature for three weeks after which they were analyzed to determine their free oleic acid content. The results of these analyses are set forth in Table I:
• rocker arm balls containing inhibited oleic acid were heated in the presence of an indicator and it was found that the inhibitor in all cases was temperature sensitive. At temperatures higher than 200F the reaction between iron and oleic acid proceeded at a rapid rate even though an inhibitor was present.
• the impregnated iron articles of this invention may be employed directly in accordance with the process of the invention by bringing the mating surfaces together with sufficient force and in sliding contact to create friction that will raise the temperature of local surface aberrations above the effective temperature of the inhibitor.
• Surfaces such as valves and valve seats to be used in a cold environment may be so prepared. If oleic acid is not wanted in the final structure, it may be removed by conventional methods such as immersing the part in a solvent or employing the solvent with ultrasonic vibrations.
• a particularly useful embodiment of the invention is to install the oleic acid-impregnated part in a final assembly and to have the surfaces to be in sliding contact matched during the operation of the final assembly.
• the rocker arm balls described above may be so employed.
• oleic acid-impregnated sintered iron rocker arm balls may be assembled in the normal manner and the process for producing matched surfaces may be effected when the finally assembled internal combustion engine is put into operation.
• the sliding contact between the rocker arm balls and their sockets will produce virtually perfectly matching surfaces.
• An article of manufacture comprising a porous, sintered iron article having in the pores thereof oleic acid containing an inhibitor selected from the group consisting of N,N'bis (l, 4-dimethyl pentyl)-pphenylene diamine, t-butyl hydroxy anisol, t-butyl hydroxy toluene, and mono-t-butyl hydroquinone in an amount effective to inhibit the reaction between iron and oleic acid at room temperature.
• an inhibitor selected from the group consisting of N,N'bis (l, 4-dimethyl pentyl)-pphenylene diamine, t-butyl hydroxy anisol, t-butyl hydroxy toluene, and mono-t-butyl hydroquinone in an amount effective to inhibit the reaction between iron and oleic acid at room temperature.
• inhibitor N,N'bis (l, 4-dimethyl pentyl)-p-phenylene diamine.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Powder Metallurgy (AREA)
• Valve-Gear Or Valve Arrangements (AREA)
• Sliding-Contact Bearings (AREA)

Priority Applications (3)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23284643

Family Applications (1)

Country Status (3)

Cited By (3)

Families Citing this family (2)

Citations (6)

Family Cites Families (1)

• 1973
  • 1973-02-02 US US00329271A patent/US3804600A/en not_active Expired - Lifetime
• 1974
  • 1974-01-17 CA CA190,418A patent/CA1018508A/en not_active Expired
  • 1974-02-01 JP JP1357974A patent/JPS572123B2/ja not_active Expired

Patent Citations (6)

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