Patent attributes
A chain cover includes a first member, which is made of a hard plastic, and a second member, which is made of a material different from the hard plastic. The first member is formed by insert molding with the second member as an insert. A first joint surface is formed in a peripheral portion around an insertion hole. The first joint surface is joined to the first member. The first joint surface includes a first joint portion, which includes a lattice-shaped recess portion, and a second joint portion, which includes grooves. The grooves extend in a direction in which the peripheral portion extends, while being arranged in an intersecting direction, which intersects with the extending direction. The second joint portion is provided to be closer to a space adjacent to the peripheral portion than the first joint portion.