Boot for constant velocity universal joint

A boot for a tripod joint, the tripod joint having a plurality of axial-direction grooves formed at predetermined intervals in a peripheral direction in an outer peripheral surface of a casing with an outer housing having one end opening, and a peripheral direction groove and a protrusion portion between the peripheral direction groove and an opening end portion respectively formed on a surface portion of the outer peripheral surface other than a surface portion forming an axial direction groove, the boot comprising:

• a large-diameter-side end portion for receiving the casing of the tripod joint;
• a small-diameter-side end portion for receiving a shaft portion connected to the tripod joint;
• and
• a bellows portion formed between the large-diameter-side end portion and the small-diameter-side end portion,
• the large-diameter-side end portion being fastenable/fixable to the tripod joint casing from a side of the outer peripheral surface via a band,
• the large-diameter-side end portion including:
• a thick portion facing the axial-direction groove of the casing and protruding from an inner peripheral surface;
• one or a plurality of seal lips in a form of a protrusion over an entire periphery of the inner peripheral surface of the large-diameter-side end portion;
• the large-diameter-side end portion further including
• shift preventive walls disposed on opposite sides of the one or the plurality of seal lips and the shift preventive walls having inner diameters smaller than an inner diameter of base portions of the one or the plurality of seal lips,
• the shift preventive walls and the one or the plurality of seal lips being disposed right under a band fastening portion,
• the shift preventive walls connecting with the protrusion portion of the outer housing so as to be inserted in an axial direction.