Combination seal ring encoder

A bearing unit for an automobile, comprising a rotational ring and a fixed ring with a space of 4.0 mm to 7.0 mm therebetween and having a combination seal ring incorporated therein, and the combination seal ring being for use between a the fixed ring having a circumferential face and a the rotational ring having a circumferential face wherein a space exists between the circumferential face of the fixed ring and the circumferential face of the rotational ring and has an end portion with an opening, so as to close off the opening of the space and to detect a rotational speed of the rotational ring,

• the combination seal ring comprising:
• a seal ring secured to the circumferential face of the fixed ring,
• a slinger made of metal and secured to the circumferential face of the rotational ring, and
• an encoder supported by and secured to the slinger,
• the seal ring comprising a metal core consisting of a fixed cylindrical portion which has an end rim and is fitted and secured to the circumferential face of the fixed ring, and a fixed circular ring portion bent toward the circumferential face of the rotational ring from the end rim of the fixed cylindrical portion, and a resilient member bonded all around the metal core and having seal lips with an end rim,
• the slinger comprising a rotational cylindrical portion which has an end rim and is fitted and secured to the circumferential face of the rotational ring, and a rotational circular ring portion which is bent toward the circumferential face of the fixed ring from the end rim of the rotational cylindrical portion, and the rotational circular ring portion having a first side face and second side face axially opposite to each other,
• the slinger having a smooth surface portion on the circumferential face of the rotational cylindrical portion and on the first side face of the rotational circular ring portion, respectively, against which the respective end rim of the seal lips is rubbed,
• the encoder being made of a rubber magnet in which S poles and N poles are alternatively arranged in the circumferential direction, and bonded and supported on the second side face of the rotational circular ring portion, which is opposite to the seal lips, and the encoder bonded to the rotational circular ring portion by a molding process, wherein this second side face is utilized for molding,
• the encoder having a height in cross section of from 2.0 mm to 7.0 mm.