Ceramic to metal joint assembly

A joint assembly, comprising:

• a ceramic shaft portion integral with a ceramic member:
• a shrink fitter formed of a first material being disposed around said ceramic shaft portion and having an inner surface facing said ceramic shaft portion;
• a layer of solid lubricant;
• said layer of solid lubricant deposited on said inner surface of said shrink fitter;
• said layer of solid lubricant being in torque transmitting contact with said ceramic shaft portion and defining a first interface surface with said ceramic shaft portion;
• a sleeve formed of a second material disposed around and in torque transmitting contact with said shrink fitter defining a second interface surface therebetween;
• and
• said shrink fitter integral with a metal member;
• wherein a diameter of said first interface surface, d1, and a diameter of said second interface surface, d2, are related as
• d1/d2=(αc−α1)/(α2−α1),
• where αc is the coefficient of thermal expansion of said ceramic shaft portion, α1 is the coefficient of thermal expansion of said first material, and α2 is the coefficient of thermal expansion of said second material.

A joint assembly, comprising:

• a ceramic shaft portion integral with a ceramic member;
• a shrink fitter formed of a first material being disposed around said ceramic shaft portion and having an inner surface facing said ceramic shaft portion;
• a layer of solid lubricant;
• said layer of solid lubricant deposited on said inner surface of said shrink fitter;
• said layer of solid lubricant being in torque transmitting contact with said ceramic shaft portion and defining a first interface surface with said ceramic shaft portion;
• a sleeve formed of a second material disposed around and in torque transmitting contact with said shrink fitter defining a second interface surface therebetween;
• and
• wherein said shrink fitter is integral with a metal member.

A joint assembly, comprising:

• a ceramic shaft portion integral with a ceramic member;
• a shrink fitter formed of a first material being disposed around said ceramic shaft portion and having an inner surface facing said ceramic shaft portion;
• a layer of solid lubricant;
• said layer of solid lubricant deposited on said inner surface of said shrink fitter;
• said layer of solid lubricant being in torque transmitting contact with said ceramic shaft portion and defining a first interface surface with said ceramic shaft portion;
• a sleeve formed of a second material disposed around and in torque transmitting contact with said shrink fitter defining a second interface surface therebetween;
• and
• wherein said shrink fitter has a plurality of circumferentially spaced apart, longitudinally extending slots, whereby, during operation of the assembly, a width of each of the slots decreases to translate a hindered radial expansion displacement of said shrink fitter into circumferential displacement.

A joint assembly, comprising:

• a ceramic shaft portion integral with a ceramic member;
• a compliant sleeve disposed around and in torque transmitting contact with said ceramic shaft portion defining a first interface surface therebetween;
• a shrink fitter formed of a first material disposed around and in torque transmitting contact with said compliant sleeve;
• a sleeve formed of a second material disposed around and in torque transmitting contact with said shrink fitter defining a second interface surface therebetween;
• and
• one of said shrink fitter and said sleeve integral with a metal wherein a diameter of said first interface surface, d1, and a diameter of said second interface surface, d2, are related as
• d1/d2=(αc−α1)/(α2−α1),
• where αc is the coefficient of thermal expansion of said ceramic shaft portion, α1 is the coefficient of thermal expansion of said first material, and α2 is the coefficient of thermal expansion of said second material.

A joint assembly, comprising:

• a ceramic shaft portion integral with a ceramic member;
• a compliant sleeve disposed around and in torque transmitting contact with said ceramic shaft portion defining a first interface surface therebetween;
• said compliant sleeve comprising:
• a superalloy substrate having an outer and inner surface;
• a soft metal layer covering said inner surface;
• said soft metal layer having a lower yield strength than said substrate;
• a first lubricant over said outer surface;
• and
• a second lubricant covering said soft metal layer;
• a shrink fitter formed of a first material disposed around and in torque transmitting contact with said compliant sleeve;
• a sleeve formed of a second material disposed around and in torque transmitting contact with said shrink fitter defining a second interface surface therebetween;
• and
• one of said shrink fitter and said sleeve integral with a metal member.