Passively operated thermally diodic packaging method for missile avionics

A passively operated thermal diode for controlling heat transfer from heat-generating electronic components to an external environment through an airframe, said thermal diode comprising:

• (a) an electronics package provided with at least one first tapered surface;
• (b) a heat-transferring mechanism provided with at least one second tapered surface that slidably mates with said at least one first tapered surface;
• (c) a shape-memory alloy actuator having a phase change at a predetermined temperature for thermally disconnecting said electronics package from said first tapered surface once said predetermined temperature is exceeded;
• and
• (d) a spring for maintaining said heat-transferring mechanism in thermal contact with said airframe below said predetermined temperature.

A passively operated thermal diode for controlling heat transfer from heat-generating electronic components to an external environment through an airframe, said thermal diode comprising:

• (a) a portion of an inner surface of said airframe provided with two tapered surfaces, a first tapered surface having a comparatively large contact area and a comparatively shallow taper and a second tapered surface having a comparatively small contact area and a comparatively steep taper;
• (b) an electronics package thermally connected to a heat sink also provided with two tapered surfaces, a third tapered surface having a comparatively large contact area and a comparatively shallow taper and a fourth tapered surface having a comparatively small contact area and a comparatively steep taper, with said heat sink configured (1) with its third tapered surface opposed to said first tapered surface and with its fourth tapered surface opposed to said second tapered surface and (2) to slidably move from contact of said first and third surfaces to contact of said second and fourth surfaces;
• (c) a shape-memory alloy washer having a phase change at a predetermined temperature for thermally disconnecting said heat sink from said first tapered surface once said predetermined temperature is exceeded;
• and
• (d) a spring washer for maintaining said heat sink in thermal contact with said airframe below said predetermined temperature.