Grease composition and rolling device
AssigneeNsk Ltd.
InventorsAzuma Ito, Tomoaki Matsumoto, Haruhisa Ashida
Life of this patent
Estimating the term…
Abstract
Provided are a grease composition and a rolling device which can prevent a decrease in seal performance even when a low-viscosity base oil having, for example, a kinematic viscosity of 5 to 40 mm2/s is used, and can achieve both seal performance and low torque. A seal member (12a) has a plurality of seal lips (114), (115), and (116) made of an elastic material, and a grease composition is sealed in gap portions (121) and (122) between a sliding surface of a slinger (106) on which the seal lips slide and the two adjacent seal lips. The grease composition contains a base oil and a polar polymer, and a weight-average molecular weight of the polar polymer is from 5000 to 140000.
Claims8
A grease composition to be used in a rolling device comprising a pair of bearing rings having a pair of opposing raceway surfaces, a plurality of rolling elements rollably held between the pair of raceway surfaces, and a seal member closing an opening end portion of a space formed between the pair of bearing rings, wherein the seal member has a plurality of seal lips made of an elastic material, wherein
- the grease composition is filled in a gap portion between a sliding surface on which the seal lips of one of the pair of bearing rings slide and two adjacent seal lips, and the grease composition comprises:
- a base oil;
- and a polar polymer, wherein
- a weight-average molecular weight of the polar polymer is from 5000 to 140000, and
- a kinematic viscosity of the base oil at 40° C. is 5 mm2/s or more and 20 mm2/s or less.
A rolling device comprising:
- a pair of bearing rings having a pair of opposing raceway surfaces;
- a plurality of rolling elements rollably held between the pair of raceway surfaces;
- and a seal member closing an opening end portion of a space formed between the pair of bearing rings, the seal member having a plurality of seal lips made of an elastic material, wherein
- a grease composition is filled in a gap portion between a sliding surface on which the seal lips of one of the pair of bearing rings slide and two adjacent seal lips,
- the grease composition contains a base oil and a polar polymer, and
- a weight-average molecular weight of the polar polymer is from 5000 to 140000, and
- a kinematic viscosity of the base oil at 40° C. is 5 mm2/s or more and 20 mm2/s or less.
Dependencies are inferred from the claim text.