| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing for wheel in which a foreign matter is hard to be caught between a magnetometric sensor and an encoder grating and in which the encoder grating is not damaged even when the foreign matter is caught. SOLUTION: The bearing for wheel is composed of an inside member 1, an outside member 2, a plurality of rolling bodies 3 which are housed between the inside member and the outside member and a seal device 5 which airtightly seals the end part of a ring-shaped space between the inside member 1 and the outside member 2. The seal device 5 is provided with a first ring-shaped seal plate 11 and a second ring-shaped seal plate 12 which are attached respectively to the mutually different members from among the inside member 1 and the outside member 2. Both seal plates 11, 12 are formed to be cross-sectional L-shapes composed of cylindrical parts 11a, 12a and erect plate parts 11b, 12b so as to be faced. The first seal plate 11 is fitted to the retation-side member from among the inside member 1 and the outside member 2. An elastic member 14 with which a magnetic substance powder is mixed is vulcanized and bonded to the erect plate part 11b. A protective cover 18 which is made of a nonmagnetic substance is installed at the outside of the elastic member 14 so as to be opposed to the elastic member while keeping a prescribed air gap. The speed of rotation of the wheel bearing is detected via the protective cover 18.
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