Grease composition, machine component, and starter overrunning clutch
AssigneesDenso Corporation, DuPont Toray Specialty Materials Kabushiki Kaisha
InventorsYoshinori Fukushima, Youichi Hasegawa, Yuji Masamura, Makoto Mori, Koji Sakakibara
Life of this patent
Estimating the term…
Abstract
A silicone grease composition is disclosed. The grease composition contains a silicone oil and zinc dialkyldithiocarbamate as an extreme-pressure additive. The grease composition contains substantially no zinc dialkyldithiophosphate. The grease composition achieves high friction characteristics and wear characteristics. A method for transmitting torque of a clutch or a torque limiter mechanism is also disclosed. Moreover, a method for producing a clutch or a torque limiter mechanism is disclosed. The methods utilize the aforementioned grease composition.
Claims18
A method for transmitting torque of a clutch or a torque limiter mechanism, the method comprising:
- enclosing a grease composition in a lubricating part of the clutch or the torque limiter mechanism;
- wherein the enclosed grease composition consists of:
- (A) a silicone oil having the general formula (I):
- R1aSiO(4-a)/2 in which each R1 is independently selected from the group consisting of monovalent hydrocarbon groups, and a is from 1.8 to 2.2;
- (B) zinc dialkyldithiocarbamate having the general formula (II):
- [R52N—C(═S)—S]2—Zn in which each R5 is a methyl group;
- and
- (C) an organic thickener selected from the group consisting of lithium soap and lithium complex soap;
- wherein a content of the silicone oil (A) is from 60 mass % to 90 mass %, a content of the zinc dialkyldithiocarbamate (B) is from 7.5 mass % to 20 mass %, and a content of the organic thickener (C) is from 2.5 mass % to 20 mass %, each relative to the total amount of the enclosed grease composition, provided the total of components (A), (B), and (C) is 100 mass % of the enclosed grease composition.
A method for transmitting torque of a clutch or a torque limiter mechanism, the method comprising:
- providing an automobile starter, the automobile starter having the clutch or torque limiter mechanism;
- providing a grease composition;
- enclosing the grease composition in a lubricating part of the clutch or the torque limiter mechanism of the automobile starter;
- and
- powering the automobile starter, thereby transmitting torque of the clutch or torque limiter mechanism via the enclosed grease composition;
- wherein the enclosed grease composition consists of:
- (A) a silicone oil having the general formula (I):
- R1aSiO(4-a)/2 in which each R1 is independently selected from the group consisting of monovalent hydrocarbon groups, and a is from 1.8 to 2.2;
- (B) zinc dialkyldithiocarbamate having the general formula (II):
- [R52N—C(═S)—S]2—Zn in which each R5 is a methyl group;
- and
- (C) an organic thickener selected from the group consisting of lithium soap and lithium complex soap;
- wherein a content of the silicone oil (A) is from 60 mass % to 90 mass %, a content of the zinc dialkyldithiocarbamate (B) is from 7.5 mass % to 20 mass %, and a content of the organic thickener (C) is from 2.5 mass % to 20 mass %, each relative to the total amount of the enclosed grease composition, provided the total of components (A), (B), and (C) is 100 mass % of the enclosed grease composition.
Dependencies are inferred from the claim text.