Injection-molded body
View Patent ↗An injection-molded body according to the present invention includes a tubular body portion, an airtight seal surface formed on a peripheral surface of the body portion near one end of the body portion, and a plurality of undercuts disposed at positions around the peripheral surface of the body portion that are closer to the end than the airtight seal surface is. The undercuts prevent a seal member mounted on the airtight seal surface from falling off, in which a clearance is formed between a peripheral wall and the undercuts. The peripheral wall defines an inner hole of the body portion, and the clearance accommodates deformation of the undercuts in radial directions.
1. An injection-molded body, comprising:
a tubular body portion;
an airtight seal surface formed on a peripheral surface of the body portion near one end of the body portion; and
a plurality of undercuts disposed at positions around the peripheral surface of the body portion, the positions being closer to the end than the airtight seal surface is, the undercuts preventing a seal member mounted on the airtight seal surface from falling off,
wherein a clearance is formed between a peripheral wall and the undercuts, the peripheral wall defining an inner hole of the body portion, the clearance accommodating deformation of the undercuts in radial directions.
2. The injection-molded body according to claim 1 ,
wherein the inner hole is formed as an insertion hole, a rotating shaft for rotating the body portion being inserted into the insertion hole, and
wherein the clearance is formed along an entire periphery of the peripheral wall.
3. The injection-molded body according to claim 1 ,
wherein a cutout is formed between the undercuts.
4. The injection-molded body according to claim 3 ,
wherein the cutout has a depth substantially corresponding to a dimension of an area for formation of the undercuts.