Hub unit

A hub unit comprising:

• an outer ring member;
• an inner ring member including a flange part to which a wheel is to be mounted, a large diameter part, a small diameter part which has an outer circumference channel extending circumferentially in an end thereof and a plurality of notches defined therein which open the outer circumference channel to an end surface of the small diameter part, and a shoulder defined between said large and said small diameter parts;
• a sleeve disposed over the small diameter part of the inner ring member, one end of the sleeve contacting said shoulder, and the other end of said sleeve overhanging the outer circumference channel when said sleeve is disposed over said small diameter part with said one end thereof abutting said shoulder;
• a plurality rolling elements positioned at regular intervals between the inner circumferential surface of said outer ring member and the outer circumferential surface of said large diameter part of the inner ring member and between the inner circumferential surface of said outer ring member and the outer circumferential surface of said sleeve;
• a ring-shaped bayonet member having a plurality of engaging parts which respectively project radially inwardly at positions corresponding to the positions of said notches defined in the inner ring member, each of said engaging parts having a tapered portion, each of said engaging parts being insertable through a respective one of said notches,
• said ring-shaped bayonet member having a portion thereof extending between, in a thickness-wise direction thereof, and contacting a surface of said inner ring member defining a side of said circumference channel and said other end of said sleeve,
• said portion of the ring-shaped bayonet member including a portion of each of said engaging elements which contacts said surface of said ring member defining said side of said circumference channel, and
• said portion of the ring-shaped bayonet member having a preassembly thickness greater than the difference between the distance from said shoulder to said surface of said inner ring member defining said side of said circumference channel and the distance from said shoulder to said other end of said sleeve, when said sleeve is disposed over said small diameter part prior to assembly of said bayonet member with said one end thereof abutting said shoulder, such that said bayonet member presses said sleeve against said shoulder and is in turn wedged between said sleeve and said surface defining said side of said circumference channel.