Lubricant composition for speed reducer and speed reducer

• US 11,021,672 B2
• Filed: 12/08/2016
• Issued: 06/01/2021
• Est. Priority Date: 12/25/2015
• Status: Active Grant

• Current Assignee: Kyodo Yushi Co., Ltd., Nabtesco Corporation
• Original Assignee: Kyodo Yushi Co., Ltd.
• Inventors: Imai, Junichi, Ichimura, Ryosuke, Saito, Ryosuke, Tanimura, Ko, Wang, Hongyou, Kumagai, Takahide, Hattori, Yasuyuki
• Primary Examiner(s): Singh, Prem C
• Assistant Examiner(s): Campanell, Francis C
• Application Number:
  US15/372,898
• Publication Number:
  US 20170183603A1
• Time in Patent Office: 1,636 Days
• Field of Search: 508390, 508241
• CPC Class Codes: C10M 117/04 containing hydroxy groups
• CPC Class Codes: C10M 137/10 Thio derivatives
• CPC Class Codes: C10M 169/044 the additives being a mixture of non-macromolecular and macromolecular compounds
• CPC Class Codes: C10M 169/047 the additives being a mixture of compounds of unknown or incompletely defined constitution and macromolecular compounds
• CPC Class Codes: C10M 169/06 Mixtures of thickeners and additives
• CPC Class Codes: C10M 2203/003 used as base material
• CPC Class Codes: C10M 2203/024 unsaturated
• CPC Class Codes: C10M 2203/1006 used as base material
• CPC Class Codes: C10M 2205/022 Ethene
• CPC Class Codes: C10M 2205/024 Propene
• CPC Class Codes: C10M 2205/0285 used as base material
• CPC Class Codes: C10M 2205/12 Oxidised hydrocarbons, i.e. oxidised subsequent to macromolecular formation
• CPC Class Codes: C10M 2205/14 Synthetic waxes, e.g. polythene waxes
• CPC Class Codes: C10M 2207/1256 used as thickening agent
• CPC Class Codes: C10M 2207/1265 used as thickening agent
• CPC Class Codes: C10M 2207/1285 used as thickening agents
• CPC Class Codes: C10M 2219/044 Sulfonic acids, Derivatives thereof, e.g. neutral salts
• CPC Class Codes: C10M 2219/046 Overbasedsulfonic acid salts
• CPC Class Codes: C10M 2219/066 Thiocarbamic type compounds
• CPC Class Codes: C10M 2223/045 Metal containing thio derivatives
• CPC Class Codes: C10N 2020/02 : Viscosity; Viscosity index
• CPC Class Codes: C10N 2030/02 : Pour-point; Viscosity index
• CPC Class Codes: C10N 2030/06 : Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2030/08 : Resistance to extreme temperature
• CPC Class Codes: C10N 2040/04 : Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
• CPC Class Codes: C10N 2050/10 : Semi-solids; greasy

Abstract

The invention provides a lubricant composition for an eccentrically oscillating speed reducer of planetary gear type, which is capable of extending the life of the speed reducer under high temperatures and keeping low input torque at low temperatures, and includes (a) a base oil containing a synthetic oil, (b) a hydrocarbon wax, and (c) at least one calcium salt selected from the group consisting of a calcium salt of petroleum sulfonic acid, a calcium salt of alkyl aromatic sulfonic acid, a calcium salt of oxidized wax, an overbasic calcium salt of petroleum sulfonic acid, an overbasic calcium salt of alkyl aromatic sulfonic acid, and an overbasic calcium salt of oxidized wax.

Claims

1. A lubricant composition for an eccentrically oscillating speed reducer of planetary gear type, consisting of:

(a) a base oil which is a poly-alpha-olefin or a mixture of a poly-alpha-olefin and a mineral oil,

(b) a hydrocarbon wax which is a polypropylene wax or a ethylene-propylene copolymer wax, each of said waxes having a weight-average molecular weight of 1,000 to 20,000,

(c) at least one calcium salt selected from the group consisting of a calcium salt of petroleum sulfonic acid, a calcium salt of alkyl aromatic sulfonic acid, a calcium salt of oxidized wax, an overbasic calcium salt of petroleum sulfonic acid, an overbasic calcium salt of alkyl aromatic sulfonic acid, and an overbasic calcium salt of oxidized wax, and

(d) an optional additive.

2. The lubricant composition for the speed reducer of claim 1, wherein the hydrocarbon wax (b) is polypropylene wax.

3. The lubricant composition for the speed reducer of claim 1, wherein the hydrocarbon wax (b) is contained in an amount of 0.1 to 20 mass % of the total mass of the composition.

4. The lubricant composition for the speed reducer of claim 1, wherein the base oil (a) has a kinematic viscosity at 40°

C. of 20 to 300 mm²/s.

5. The lubricant composition for the speed reducer of claim 1, wherein the calcium salt (c) is a combination of calcium salts of alkyl aromatic sulfonic acid and overbasic calcium salts of alkyl aromatic sulfonic acid.

6. An eccentrically oscillating speed reducer of planetary gear type, where the lubricant composition of claim 1 is enclosed.

12. The lubricant composition for the speed reducer of claim 1, wherein the hydrocarbon wax (b) has a melting viscosity of 25,000 to 30,000 mPa·

s at 140°

C. or a melting viscosity of 9,000 to 10,000 mPa·

s at 170°

C.

13. The lubricant composition for the speed reducer of claim 1, wherein the hydrocarbon wax (b) has a dropping point of 100 to 150°

C.

14. The lubricant composition for the speed reducer of claim 1, wherein the hydrocarbon wax (b) has an acid value of 0 to 10 mgKOH/g.

7. A lubricant composition for an eccentrically oscillating speed reducer of planetary gear type, comprising:

(a) a base oil which is a poly-alpha-olefin or a mixture of a poly-alpha-olefin and a mineral oil,

(b) a hydrocarbon wax which is a polypropylene wax or a ethylene-propylene copolymer wax,

(c) at least one calcium salt selected from the group consisting of a calcium salt of petroleum sulfonic acid, a calcium salt of alkyl aromatic sulfonic acid, a calcium salt of oxidized wax, an overbasic calcium salt of petroleum sulfonic acid, an overbasic calcium salt of alkyl aromatic sulfonic acid, and an overbasic calcium salt of oxidized wax, and

(d) a thickener,

wherein the thickener is selected from the group consisting of Li soap thickeners and urea thickeners, and the lubricant composition has a worked penetration of 350 to 450.

8. The lubricant composition for the speed reducer of claim 7, wherein the hydrocarbon wax (b) has a weight-average molecular weight of 1,000 to 20,000.

9. The lubricant composition for the speed reducer of claim 7, wherein the hydrocarbon wax (b) has a melting viscosity of 25,000 to 30,000 mPa·

s at 140°

C. or a melting viscosity of 9,000 to 10,000 mPa·

s at 170°

C.

10. The lubricant composition for the speed reducer of claim 7, wherein the hydrocarbon wax (b) has a dropping point of 100 to 150°

C.

11. The lubricant composition for the speed reducer of claim 7, wherein the hydrocarbon wax (b) has an acid value of 0 to 10 mgKOH/g.

15. The lubricant composition for the speed reducer of claim 7, which has a worked penetration of 395 to 425.