Provided is a plastic injection-molding method for producing a poly-V belt pulley, which has an outer ring, an inner ring, and a ring web, which connects the outer ring to the inner ring and has a plurality of radially oriented ribs. The injection molding occurs in a circular-ring-shaped injection-molding cavity, a poly-V-ribbed inner shell of which is formed by a plurality of radially movable slides and which is vented during the injection molding by the gaps between the slides adjacent to each other. The rib contour in the injection-molding cavity are designed in such a way that the plurality of ribs is formed of a first group of thin ribs and a second group of thick ribs and that the gaps extend in radial extension of the thin ribs, the width of which is significantly less than the width of the thick ribs, which extend circumferentially between the gaps.

Provided is a plastic injection-molding method for producing a poly-V belt pulley, which has an outer ring, an inner ring, and a ring web, which connects the outer ring to the inner ring and has a plurality of radially oriented ribs. The injection molding occurs in a circular-ring-shaped injection-molding cavity, a poly-V-ribbed inner shell of which is formed by a plurality of radially movable slides and which is vented during the injection molding by the gaps between the slides adjacent to each other. The rib contour in the injection-molding cavity are designed in such a way that the plurality of ribs is formed of a first group of thin ribs and a second group of thick ribs and that the gaps extend in radial extension of the thin ribs, the width of which is significantly less than the width of the thick ribs, which extend circumferentially between the gaps.

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.

Embodiments of the present disclosure relate to a transmission gear and a deceleration mechanism including the same. The transmission gear includes a metal ring; and a plastic gear member integral with the metal ring by injection molding, the metal ring is coaxially wrapped in the plastic gear member and provided with a locating portion for locating the metal ring in an injection mold, the plastic gear member having an outer circumference that is tooth-shaped, and the plastic gear member being formed with an input hole thereon through which an input shaft passes, an outer ring surface of the metal ring being adjacent to the outer circumference, and an inner ring surface of the metal ring having a diameter greater than or equal to that of the input hole. Since almost no shrinkage occurs to the plastic gear member during injection molding, such a transmission gear has good dimensional accuracy, strength and rigidity.

The present disclosure provides a pulley, comprising a cylindrical wall having an outer surface with a plurality of circumferential grooves configured to receive a corresponding plurality of ribs on an inner surface of an elastic belt, a web connected to an inner surface of the cylindrical wall, a central hub connected to the web, the central hub comprises a central opening sized to be press-fit onto a drive shaft, and a drive feature configured to mate with a drive tool, thereby facilitating rotation of the pulley using the drive tool.

A hybrid drive component, such as a pulley, a drive sprocket, or an idler is composed of metal and composite material. The drive component manufacturing methods extend the overall life of the pulley while also reducing material usage and product weight thereby making the application more efficient. The drive component includes a drive element, a hub/bearing element and a connecting element. The connecting element is a molded construction that interconnects the drive element and the hub element.

A hybrid drive component, such as a pulley, a drive sprocket, or an idler is composed of metal and composite material. The drive component manufacturing methods extend the overall life of the pulley while also reducing material usage and product weight thereby making the application more efficient. The drive component includes a drive element, a hub/bearing element and a connecting element. The connecting element is a molded construction that interconnects the drive element and the hub element.

A pulley assembly for belt tensioners having a bearing unit provided with a rotating outer ring and made of metal, an outer wheel body overmoulded onto the outer ring to rotate with the outer ring and interact with a belt, a gripping surface at the interface between the outer wheel body and the outer ring to prevent circumferential slipping between the outer wheel body and the outer ring; and an axial retainer integral with the outer ring and having two lateral edge members located axially on opposite sides of the gripping surface to engage the outer wheel body and prevent axial movement of the outer wheel body relative to the outer ring.

A pulley body has a first flange and a fitting protrusion. The flange body has a second flange and a fitting recess fitted to the fitting protrusion. The fitting recess has an inner surface including, in a radially inward direction, a first inclined surface inclined so as to approach the first flange, as extending in the radially inward direction. The fitting protrusion has a distal end surface including, in the radially inward direction, a second inclined surface facing the first inclined surface. The flange body has an outer peripheral surface that faces an inner peripheral surface of the pulley body, and has a protrusion which continues in a circumferential direction with no end. A region including an annular-shaped area between the first and second inclined surfaces includes a joint portion of a molten resin.

In a torsional damper, a damper mass is connected to a hub through a damper rubber. The hub is provided with a boss fixed to a crankshaft and a rim holding the damper rubber. The boss and the rim are coupled by plurality of spokes. The plurality of spokes each has an inclined shape inclined in the axial direction. Reinforcement portion is provided in the spokes in one direction corresponding to a bending vibration to be input among the plurality of spokes.