A method of manufacturing a wheel has a step (a) during which, by injecting a first polymer material into a first mould, a bearing core is created that extends from a radially internal wall that forms the ball of a steering axis, as far as a radially external peripheral edge, followed by a step (b) of coating during which step a coating layer is overmoulded in a second polymer material over the bearing core to form a rim around the peripheral edge, the method being such that during step (a) of creating the bearing core, a preformed reinforcing hoop made of a third material referred to as “reinforcing material” is placed in the first mould then the reinforcing hoop is at least partially embedded in the peripheral edge during injection of the first material.

A method of making a worm gear is provided. The method comprises forming a gear hub from a powdered metal material. Thereafter an outer surface of the gear hub is sealed.

The present invention is intended to provide a method for manufacturing a resin gear with a core metal by which there is no reduction in strength even with gates allowing decrease in material costs such as pin gates in the molding die for injection molding. The manufacturing method includes: gates at a primary molding step and gates at a secondary molding step are pin gates or the like. The number of the gates at the primary molding step and the number of the gates at the secondary molding step are plural and identical, and the gates are arranged circumferentially. Gate positions G21, . . . at the secondary molding step are circumferentially intermediate or nearly circumferentially intermediate between gate positions G11, . . . and weld positions W11, . . . adjacent to the gate positions G11, . . . in the primary molded article.

A method of manufacturing a wheel has a step (a) during which, by injecting a first polymer material into a first mold, a bearing core is created that extends from a radially internal wall that forms the ball of a steering axis, as far as a radially external peripheral edge, followed by a step (b) of coating during which step a coating layer is overmolded in a second polymer material over the bearing core to form a rim around the peripheral edge, the method being such that during step (a) of creating the bearing core, a preformed reinforcing hoop made of a third material referred to as reinforcing material is placed in the first mold then the reinforcing hoop is at least partially embedded in the peripheral edge during injection of the first material.

The invention relates to a method for producing a gear, said method including a step (a) during which a supporting core is made from a first polymer material, said supporting core comprising a hub, with a director axis (XX), as well as a flange which extends radially from said hub to a peripheral flanged edge, said method then involves a coating step (b) which comprises producing a permanent coating layer, made of a second polymer material, by overmolding on the supporting core, including integrally both a front layer which covers the upper surface of the flange, and a side layer which extends said front layer axially by covering the outer radial surface of the flanged edge, such that said side layer forms a rim, the teeth of the gear being made in the radial body of said rim.

The invention relates to a method for producing a gear, said method including a step (a) during which a supporting core is made from a first polymer material, said supporting core comprising a hub, with a director axis (XX), as well as a flange which extends radially from said hub to a peripheral flanged edge, said method then involves a coating step (b) which comprises producing a permanent coating layer, made of a second polymer material, by overmoulding on the supporting core, including integrally both a front layer which covers the upper surface of the flange, and a side layer which extends said front layer axially by covering the outer radial surface of the flanged edge, such that said side layer forms a rim, the teeth of the gear being made in the radial body of said rim.

The present invention is intended to provide a method for manufacturing a resin gear with a core metal by which there is no reduction in strength even with gates allowing decrease in material costs such as pin gates in the molding die for injection molding.

The manufacturing method includes: gates at a primary molding step and gates at a secondary molding step are pin gates or the like. The number of the gates at the primary molding step and the number of the gates at the secondary molding step are plural and identical, and the gates are arranged circumferentially. Gate positions G21, . . . at the secondary molding step are circumferentially intermediate or nearly circumferentially intermediate between gate positions G11, . . . and weld positions W11, . . . adjacent to the gate positions G11, . . . in the primary molded article.