Passively operated thermally diodic packaging method for missile avionics

• US 6,404,636 B1
• Filed: 01/31/2001
• Issued: 06/11/2002
• Est. Priority Date: 01/31/2001
• Status: Expired due to Fees

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Staggers, David D., Singer, Edmund A., Ballou, Stephen L.
• Primary Examiner(s): Picard, Leo P.
• Assistant Examiner(s): CHERVINSKY, BORIS LEO
• Application Number:
  US09/774,861
• Time in Patent Office: 496 Days
• Field of Search: 361/687-690, 361/703, 361/704, 361/708, 361/717-721, 257/718, 257/719, 257/727, 174/16.3, 165/80.2, 165/104.33, 165/185
• US Class Current: 361/704
• CPC Class Codes: F42B 15/34 Protection against overheating or radiation, e.g. heat shields; Additional cooling arrangements thermal protection fitted in or to cosmonautic vehicles B64G1/58
• CPC Class Codes: H05K 7/1434 for electronics exposed to high gravitational force; Cylindrical housings
• CPC Class Codes: H05K 7/20445 the coupling element being an additional piece, e.g. thermal standoff

Abstract

A passively operated thermal diode for controlling heat transfer from heat-generating electronic components to an external environment through an airframe is provided. The thermal diode comprises: (a) an electronics package within the airframe; (b) a heat-transferring mechanism thermally connected to the electronics package and controllably disengagable from thermal contact with the airframe at a predetermined temperature; (c) a shape-memory alloy component having a phase change at the predetermined temperature for thermally disconnecting the electronics package from the airframe once the predetermined temperature is exceeded; and (d) a spring for maintaining the heat-transferring mechanism in thermal contact the airframe below the predetermined temperature. The present invention solves the problem of heat transfer by introducing a shape-memory-alloy sensor-actuator component. It deforms due to a temperature initiated phase change, thereby providing the force and motion required to change the mechanical connection between the missile avionics and the airframe from a thermally conductive path to a thermally insulating path.

Claims

1. 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 within said airframe;

(b) a heat-transferring mechanism thermally connected to said electronics package and controllably disengagable from thermal contact with said airframe at a predetermined temperature;

(c) a shape-memory alloy component having a phase change at said predetermined temperature for thermally disconnecting said electronics package from said airframe once said predetermined temperature is exceeded while remaining in thermal contact with said airframe; and

(d) a spring for maintaining said heat-transferring mechanism in thermal contact with said airframe below said predetermined temperature.

2. The thermal diode of claim 1 wherein:

(a) said electronics package is provided with at least one first tapered surface;

(b) said heat-transferring mechanism is provided with at least one second tapered surface that slidably mates with said at least one first tapered surface;

(c) said shape-memory component comprises an actuator for thermally disconnecting said heat transferring mechanism from said airframe once said predetermined temperature is exceeded; and

(d) said spring maintains said heat-transferring mechanism in thermal contact with said airframe below said predetermined temperature.

3. The thermal diode of claim 1 wherein:

(a) a portion of an inner surface of said airframe is 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) said electronics package is 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) said shape-memory alloy component comprises a washer for thermally disconnecting said heat sink from said first tapered surface once said predetermined temperature is exceeded; and

(d) said spring comprises a washer for maintaining said heat sink in thermal contact with airframe below said predetermined temperature.

4. 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.

5. 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.