Method of manufacturing a cast alloy wheel
A cast aluminum wheel includes a rim element having an annular configuration defining an axis and a central element extending radially outwardly between the axis and the rim element. The rim element includes a wall extending circumferentially around the axis between a proximal bead and a distal bead. The central element includes a plurality of spokes extending radially outwardly toward the proximal bead and meets proximate the axis with adjacent of the plurality of spokes defining a cooperative feature therebetween for providing stiffness to the wheel. The spokes progressively increase in volume in a direction toward the axis from the rim element thereby providing increased mass of the spokes proximate the axis relative to the rim element.
1. A method of manufacturing a cast alloy wheel by injection molding, comprising the steps of:
injection molding an as-cast pre-form of the cast alloy wheel defining a rim element having an annular wall circumscribing a wheel axis and a central element extending inwardly from said rim element toward said axis terminating at a hub element proximate said wheel axis;
injection molding a plurality of spokes including structural elements extending between said hub element and said rim element with said spokes defining an in-board side; and
while injection molding the cast alloy wheel, defining radius transition between adjacent surfaces of said spokes by leaving said in-board side of said spokes of said central element disposed in an as-cast dimensional configuration thereby forming as-cast structural elements of the cast alloy wheel on said in-board side of said wheel.
2. The method set forth in claim 1 , wherein further including the step of machining a portion of said rim element and a portion of a lug member while leaving said central element in an as-cast dimensional configuration.
3. The method set forth in claim 1 , wherein said step of forming a plurality of spokes is further defined by forming each spoke having structural elements comprising a first leg and a second leg, together defining an L-shaped section.
4. The method set forth in claim 1 , wherein said step of forming a plurality of spokes is further defined by forming a first leg of said spoke having a generally constant thickness in a direction toward said rim element and a second leg of said spoke progressively increasing in volume in a direction toward said axis from said rim element.
5. The method set forth in claim 1 , wherein said step of forming a plurality of spokes is further defined by forming dimensionally accurate spokes in an as-cast dimensional configuration requiring no dimensional reconfiguration of said spokes by machining.
6. The method set forth in claim 1 , further including the step of forming a lug member and machining lug apertures into said lug member.
7. The method set forth in claim 1 , wherein said step of forming a plurality of spokes is further defined by forming adjacent spokes having a cooperable structural feature disposed therebetween defined by forming at least one of intermittent L-shaped and T-shaped features in adjacent spokes.
8. The method set forth in claim 1 , further including a step of machining less than ten percent of said central element and said spokes.