Over-molded splines for rotary valves

A rotary valve assembly, comprising:

• a first rotary valve including:
• a primary shaft including a first spline piece having a primary spline feature including one or more primary splines;
• a second rotary valve including:
• a secondary shaft including a second spline piece having a secondary spline feature including one or more secondary splines;
• and
• the one or more primary splines and the one or more secondary splines configured to mesh together to form a spline joint between the first and second rotary valves;
• wherein:
• at least one of the primary or secondary shafts has a hollow portion defining an inner cavity;
• the first spline piece is formed of metal, and further includes a middle section between the primary shaft and the primary spline feature;
• and,
• a portion of the first spline piece is disposed within the hollow portion.

A method, comprising:

• over-molding a primary shaft of a first rotary valve onto a first end of a first metal spline piece, a second end of the first metal spline piece including a primary spline feature;
• over-molding a secondary shaft of a second rotary valve onto a second metal spline piece including a secondary spline feature;
• and
• coupling the primary and secondary spline features together to form a metal-on-metal spline joint between the first and second rotary valves.

A rotary valve assembly, comprising:

• a first rotary valve including:
• a primary shaft including a first spline piece having a primary spline feature including one or more primary splines;
• a second rotary valve including:
• a secondary shaft including:
• a hollow portion defining an inner cavity, the inner cavity extending from a first end of the secondary shaft to a second, opposite end of the secondary shaft;
• and,
• a metal second spline piece disposed within the hollow portion, the metal second spline piece extending from the first end of the secondary shaft to the second end and having a secondary spline feature including one or more secondary splines, the secondary spline feature located at the first end of the secondary shaft;
• the one or more primary splines and the one or more secondary splines configured to mesh together to form a spline joint between the first and second rotary valves;
• and,
• the metal second spline piece includes a tertiary spline feature at the second end of the secondary shaft that is configured to receive a tertiary shaft.