A rolling bearing (1) includes an outer ring (2), an inner ring (4), and a plurality of rolling elements (6) arranged between the outer and inner ring (2, 4). The rolling bearing (1) is provided with lubricant. The outer ring (2) has an outer contact width (b.sub.o) between the outer ring (2) and the rolling elements (6). The inner ring (4) has an inner contact width (b.sub.i) between the inner ring (4) and the rolling elements (6). A ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 1.65 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 0.97 and smaller than 1.06 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is smaller than 0.68.

Disclosed are a pre-cured single-component thermal gel and a preparation method therefor. The pre-cured single-component thermal gel is prepared from the following components in parts by weight and a platinum catalyst: 100 parts of vinyl-terminated silicone oil, 5-30 parts of branched hydrogen-containing silicone oil, 500-2500 parts of modified thermally conductive powder, and 0.01-0.3 part of an inhibitor; the content of the platinum catalyst is 2 ppm to 10 ppm on the basis of the mass of platinum; the modified thermally conductive powder is prepared by modifying thermally conductive powder with a modifier; and the modifier consists of long-chain alkyl silane and vinyl silane.

A rolling bearing (1) includes an outer ring (2), an inner ring (4), and a plurality of rolling elements (6) arranged between the outer and inner ring (2, 4). The rolling bearing (1) is provided with lubricant. The outer ring (2) has an outer contact width (b.sub.o) between the outer ring (2) and the rolling elements (6). The inner ring (4) has an inner contact width (b.sub.i) between the inner ring (4) and the rolling elements (6). A ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 1.65 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is larger than 0.97 and smaller than 1.06 or a ratio =b.sub.i/b.sub.o between the inner and outer contact width (b.sub.i, b.sub.o) is smaller than 0.68.

A thermally conductive grease composition containing a matrix resin and a thermally conductive filler. The matrix resin contains a liquid dimethylpolysiloxane (A) having a kinematic viscosity of 100 to 10,000 mm.sup.2/s at 40 C. and an ethylene-propylene copolymer (B) having a kinematic viscosity of 1 to 10,000 mm.sup.2/s at 40 C. The matrix resin contains 50 parts by mass or more and 97 parts by mass or less of the liquid dimethylpolysiloxane (A) and 3 parts by mass or more and 50 parts by mass or less of the ethylene-propylene copolymer (B) where a total amount of the liquid dimethylpolysiloxane (A) and the ethylene-propylene copolymer (B) is 100 parts by mass. The thermally conductive filler is present in an amount of 400 to 2500 parts by mass with respect to 100 parts by mass of the total amount of the liquid dimethylpolysiloxane (A) and the ethylene-propylene copolymer (B).