Toothed pulley
A toothed pulley includes a cylindrical metallic core and a resin portion including teeth. The metallic core has, at one end thereof in the axial direction, an outward flange projecting outward in the radial direction. The outward flange has a radially outer peripheral surface that is a rotation prevention shape having a plurality of parts displaced inward in the radial direction from a cylindrical surface of the radially outer peripheral surface. The radially outer peripheral surface of the outward flange is covered by the resin portion.
1. A toothed pulley comprising:
a cylindrical metallic core having an outer peripheral surface and an open interior, and
a resin portion including teeth, wherein
the cylindrical metallic core has, at a first end thereof in an axial direction parallel to a rotation axis of the toothed pulley, a bottom plate, the bottom plate extending from the outer peripheral surface inward toward the axis of rotation of the toothed pulley,
the cylindrical metallic core has, at a second end thereof in the axial direction, a first outward flange projecting outward in a radial direction,
the first outward flange has a radially outer peripheral surface extending radially beyond the outer peripheral surface of the cylindrical metallic core, the first outward flange defined by a plurality of first portions alternating with a plurality of second portions, the plurality of first portions having a first radially outer peripheral surface defining a portion of a cylindrical surface, the plurality of second portions having a second radially outer peripheral surface recessed radially inward from the cylindrical surface, the first radially outer peripheral surface and the second radially outer peripheral surface defining the outer peripheral surface of the first outward flange,
the cylindrical surface is concentric with a rotational axis of the toothed pulley,
the cylindrical metallic core, including the outer peripheral surface and the radially outer peripheral surface of the first outward flange is covered by molten thermoplastic resin that is cooled to form the resin portion, wherein the cylindrical metallic core is an insert article within the resin portion,
the bottom plate of the metallic core has a plurality of attachment holes and a plurality of through holes which the resin portion enters,
the resin portion has a bottom plate at one end thereof in the axial direction,
the bottom portion of the resin portion extends axially beyond the bottom plate of the metallic core and is disposed at least partially axially adjacent the bottom plate of the metallic core, and
the bottom plate of the resin portion is provided with a notch that provides axial exposure of each of the plurality of attachment holes in the bottom plate of the metallic core.
2. The toothed pulley according to claim 1 , wherein
the metallic core includes
a first metallic core, and
a second metallic core that is positioned outward of the first metallic core in the radial direction to have a gap relative to the first metallic core in the radial direction, the second metallic core being concentric with the first metallic core,
the first metallic core has, the bottom plate and the first outward flange,
the resin portion is made of a thermoplastic resin, and
the resin portion is a single component including a resin in the gap between the first metallic core and the second metallic core and a resin of the teeth.
3. The toothed pulley according to claim 2 , wherein
the second metallic core has, at a first end or a second end thereof in the axial direction, a second outward flange projecting radially outward,
the second outward flange has a radially outer peripheral surface defined by a plurality of first portions alternating with a plurality of second portions, the plurality of first portions having a first radially outer peripheral surface defining a portion of a cylindrical surface, the plurality of second portions having a second radially outer peripheral surface recessed radially inward from the cylindrical surface, and
the radially outer peripheral surface of the outward flange is covered by the resin portion.
4. The toothed pulley according to claim 1 , wherein
the resin portion has, at an end of the resin portion in the axial direction on a side of the first end, a resin portion outward flange projecting radially outward of a tip end of each of the teeth.
5. The toothed pulley according to claim 1 , wherein
a thickness F of a tooth bottom of each of the teeth in the resin portion in an inner diameter side thereof and whole depth E of each of the teeth satisfies E≤F≤3 mm.