Rolling bearing

• US 20030040442A1
• Filed: 03/07/2002
• Published: 02/27/2003
• Est. Priority Date: 07/02/1997
• Status: Abandoned Application

• Current Assignee: NSK Limited
• Original Assignee: NSK Limited
• Inventors: Iso, Kenichi, Matsumoto, Youichi, Yokouchi, Atsushi, Naka, Michiharu, Hachiya, Kouichi, Koizumi, Hideki
• Application Number:
  US10/091,394
• Publication Number:
  US 20030040442A1
• Time in Patent Office: Days
• US Class Current: 508/155
• CPC Class Codes: C10M 169/06 Mixtures of thickeners and additives
• CPC Class Codes: C10M 2201/00 Inorganic compounds or elements as ingredients in lubricant compositions
• CPC Class Codes: C10M 2201/061 Carbides; Hydrides; Nitrides
• CPC Class Codes: C10M 2201/062 Oxides; Hydroxides; Carbonates or bicarbonates
• CPC Class Codes: C10M 2201/065 Sulfides; Selenides; Tellurides
• CPC Class Codes: C10M 2201/066 Molybdenum sulfide
• CPC Class Codes: C10M 2201/087 Boron oxides, acids or salts
• CPC Class Codes: C10M 2201/10 Compounds containing silicon
• CPC Class Codes: C10M 2201/102 Silicates
• CPC Class Codes: C10M 2201/103 Clays; Mica; Zeolites
• CPC Class Codes: C10M 2201/105 Silica
• CPC Class Codes: C10M 2201/16 Carbon dioxide
• CPC Class Codes: C10M 2201/18 Ammonia
• CPC Class Codes: C10M 2207/106 used as thickening agents
• CPC Class Codes: C10M 2207/1206 used as thickening agents
• CPC Class Codes: C10M 2207/121 having hydrocarbon chains of seven or less carbon atoms
• CPC Class Codes: C10M 2207/125 having hydrocarbon chains of eight up to twenty-nine carbon atoms, i.e. fatty acids
• CPC Class Codes: C10M 2207/129 having hydrocarbon chains of thirty or more carbon atoms
• CPC Class Codes: C10M 2207/1406 used as thickening agents
• CPC Class Codes: C10M 2207/2613 used as thickening agents
• CPC Class Codes: C10M 2207/2626 : used as thickening agents
• CPC Class Codes: C10M 2215/006 : used as thickening agents
• CPC Class Codes: C10M 2215/026 : used as thickening agents
• CPC Class Codes: C10M 2215/04 : having amino groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10M 2215/044 : having cycloaliphatic groups
• CPC Class Codes: C10M 2215/06 : having amino groups bound to carbon atoms of six-membered aromatic rings
• CPC Class Codes: C10M 2215/0813 : used as thickening agents
• CPC Class Codes: C10M 2215/1013 : used as thickening agents
• CPC Class Codes: C10M 2215/102 : Ureas; Semicarbazides; Allophanates
• CPC Class Codes: C10M 2215/1026 : used as thickening material
• CPC Class Codes: C10M 2215/121 : used as thickening agents
• CPC Class Codes: C10M 2215/2206 : used as thickening agents
• CPC Class Codes: C10M 2215/2275 : used as thickening agents
• CPC Class Codes: C10M 2215/26 : Amines
• CPC Class Codes: C10M 2219/062 : having carbon-to-sulfur double bonds
• CPC Class Codes: C10M 2219/066 : Thiocarbamic type compounds
• CPC Class Codes: C10M 2219/068 : Thiocarbamate metal salts
• CPC Class Codes: C10M 2219/086 : containing sulfur atoms bound to carbon atoms of six-membered aromatic rings
• CPC Class Codes: C10M 2219/09 : Heterocyclic compounds containing no sulfur, selenium or tellurium compounds in the ring
• CPC Class Codes: C10M 2219/10 : Heterocyclic compounds containing sulfur, selenium or tellurium compounds in the ring
• CPC Class Codes: C10M 2219/102 : containing sulfur and carbon only in the ring
• CPC Class Codes: C10M 2219/104 : containing sulfur and carbon with nitrogen or oxygen in the ring
• CPC Class Codes: C10M 2219/106 : Thiadiazoles
• CPC Class Codes: C10M 2219/108 : Phenothiazine
• CPC Class Codes: C10M 2223/045 : Metal containing thio derivatives
• CPC Class Codes: C10M 2227/00 : Organic non-macromolecular compounds containing atoms of elements not provided for in groups C10M2203/00, C10M2207/00, C10M2211/00, C10M2215/00, C10M2219/00 or C10M2223/00 as ingredients in lubricant compositions
• CPC Class Codes: C10M 2227/06 : Organic compounds derived from inorganic acids or metal salts
• CPC Class Codes: C10M 2227/061 : Esters derived from boron
• CPC Class Codes: C10M 2227/062 : Cyclic esters
• CPC Class Codes: C10M 2227/063 : Complexes of boron halides
• CPC Class Codes: C10M 2227/065 : derived from Ti or Zr
• CPC Class Codes: C10M 2227/066 : derived from Mo or W
• CPC Class Codes: C10N 2010/00 : Metal present as such or in compounds
• CPC Class Codes: C10N 2010/02 : Groups 1 or 11
• CPC Class Codes: C10N 2010/04 : Groups 2 or 12
• CPC Class Codes: C10N 2010/06 : Groups 3 or 13
• CPC Class Codes: C10N 2040/02 : Bearings

Abstract

The invention aims to provide a rolling bearing that secures a sufficient bearing life economically even when used under such conditions that water from the outside or water formed by moisture condensation may seep into the lubricant or the bearing is affected by the vibrations, and particularly a rolling bearing suited to the electric parts and accessaries of au automobile engine, such as an alternator. To accomplish the object, the hydrogen ion exponent pH of the grease sealed into the inside of the bearing is adjusted in a range of from 7 to 13. For the same purpose, the hydrogen ion exponent pH of the grease is adjusted in a range of from 5 to 13 where a prescribed amount of an organic metal salt or ADTC is added to the grease, where a prescribed amount of an inorganic compound having an average particle size of 2 □m or smaller is added to the grease, or where a diurea compound containing an aromatic amine or a mixture of the diurea compound is added to the grease as a thickener.

Claims

1. A rolling bearing having outer and inner races and rolling elements which are rotatably put in between the outer and inner races, with a lubricant sealed into the annular space formed by the rolling elements and the races, which is characterized in that said lubricant comprises a base oil, a thickener, and a pH adjustor and has its hydrogen ion exponent pH adjusted in a range of from 7 to 13.

2. A rolling bearing according to claim 1, characterized in that said base oil has a dynamic viscosity of 40 to 400 mm²/sec at 40°

C. and comprises an oil selected from any one of mineral oils, synthetic oils, and natural oils.

3. A rolling bearing according to claim 1, characterized in that said thickener is selected from at least one of a metal soap, a complex metal soap, and a urea compound.

4. A rolling bearing according to claim 3, characterized in that said urea compound is a diurea compound comprised of an amine residue selected from at least one of a cyclohexyl group, a C_n (n=7 to 12) alkylcyclohexyl group, a C_n (n=8 to 20) straight-chain alkyl group and an isocyanate residue comprising a divalent C_n (n=6 to 15) aromatic ring-containing hydrocarbon group.

5. A rolling bearing according to claim 1, characterized in that said pH adjustor is an alkaline substance selected from at least one of an amine compound, an organic metal salt, an organic acid metal salt, and an alkaline inorganic compound.

6. A rolling bearing according to claim 5, characterized in that said amine compound is at least one of primary to tertiary amine compounds containing an aliphatic hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group, which each has carbon atoms C_n (n=1 to 24), or a derivative thereof.

7. A rolling bearing according to claim 5, characterized in that said organic metal salt or organic acid metal salt as a pH adjustor has a C_n hydrocarbon chain (n=6 to 24) which constitutes the alkyl group and a metal element, which constitutes the metal salt, selected from at least one of an alkali metal, an alkaline earth metal, aluminum and zinc.

8. A rolling bearing according to claim 5, characterized in that said alkaline inorganic compound is selected from at least one of a metal hydroxide, a metal carbonate, a metal borate, and a metal silicate.

9. A rolling bearing having outer and inner races and rolling elements which are rotatably put in between the outer and inner races, with a lubricant sealed into the annular space formed by the rolling elements and the races, which is characterized in that said lubricant comprises a base oil, a thickener, a pH adjustor, and a reaction film forming agent capable of forming a reaction film on the raceway surface or the rolling surface which is selected from at least one of an organic metal salt and an ash-free dialkyldithiocarbamic acid and has its hydrogen ion exponent pH adjusted in a range of from 5 to 13.

10. A rolling bearing according to claim 9, characterized in that said organic metal salt as a reaction film forming agent is selected from at least one of a dialkyldithiocarbamic acid compound, a dialkyldithiophosphoric acid compound, an organozinc compound, and a zinc alkylxanthogenate or a methylenebisdialkyl-dithiocarbamic acid.

11. A rolling bearing having outer and inner races and rolling elements which are rotatably put in between the outer and inner races, with a lubricant sealed into the annular space formed by the rolling elements and the races, which is characterized in that said lubricant comprises a base oil, a thickener, a pH adjustor, and 0.001 to 3 wt % of particles comprising an inorganic compound having an average particle size of 2 μ

m or smaller and has its hydrogen ion exponent pH adjusted in a range of from 5 to 13.

12. A rolling bearing according to claim 11, characterized in that said inorganic compound is selected from at least one of a metal oxide, a metal hydroxide, a metal carbonate, or a hydrate thereof;

a metal nitride;

a metal carbide;

a clay mineral;

diamond; and

a solid lubricant.

13. A rolling bearing having outer and inner races and rolling elements which are rotatably put in between the outer and inner races, with a lubricant sealed into the annular space formed by the rolling elements and the races, which is characterized in that said lubricant comprises a base oil, a pH adjustor, and a thickener selected from at least one of an aromatic diurea compound and a non-aromatic diurea compound and that said lubricant has its hydrogen ion exponent pH adjusted in a range of from 5 to 13.

14. A rolling bearing according to claim 13, characterized in that the aromatic amine residue contained in said aromatic diurea compound is a C_n (n=7 to 12) aromatic ring-containing hydrocarbon group.

15. A rolling bearing according to claim 13, characterized in that the non-aromatic amine residue contained in said aromatic diurea compound and said non-aromatic diurea compound comprises at least one of a cyclohexyl group, a C_n (n=7 to 12) alkylcyclohexyl group, and a C_n (n=-8 to 20) straight-chain alkyl group and that the diisocyanate residue is a divalent C_n (n=6 to 15) aromatic ring-containing hydrocarbon group.

16. A rolling bearing according to claim 13, characterized in that the aromatic amine residue and the non-aromatic amine residue contained in said aromatic diurea compound and said non-aromatic diurea compound are in the following relationship:

Molar ratio of aromatic amine residue/(molar ratio of aromatic amine residue+molar ratio of the non-aromatic amine residue)=0.5 to 0.95

17. A rolling bearing according to claim 13, characterized in that the content of said thickener in the lubricant is 8 to 35 wt %.