# US 6,294,853 B1 · Cooling of electromechanical actuator with phase change material and thermosyphons containing working fluid

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- Number: US 6,294,853 B1
- Document ID: US6294853B1
- Status: Granted
- Kind: B1
- Application number: 09/704,947
- Filed: 2000-11-02
- Granted: 2001-09-25
- Earliest claimed: 2000-08-02
- Assignees: The United States of America as represented by the Secretary of the Air Force
- Inventors: Lanchao Lin; John E. Leland; Rengasamy Ponnappan
- Web page: https://patentgrep.com/patent/US6294853B1

## CPC

- F28D 15/02: in which the medium condenses and evaporates, e.g. heat pipes {(heat pipes used in solar heat collectors F24S10/95; in radiators F28D1/0226; in nuclear reactors G21C15/257)}
- F28D 20/02: using latent heat
- H02K 9/225: {Heat pipes}
- Y02E 60/14: Thermal energy storage
- F28D: HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT (fluid heaters having heat generating means and heat transferring means F24H; furnaces F27; details of heat-exchange apparatus of general)
- H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53})
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A passively cooled electromechanical actuator is disclosed. The passively cooled electromechanical actuator includes a rotor having an output shaft rotatably received within a stator. A pair of inner supports connect the stator to a pair of mounting platforms. The mounting platforms are attached to the inner surfaces of an aircraft wing and are in thermal communication therewith. A pair of closed, capillary tube thermosyphons containing a working fluid are in thermal communication with the stator, the inner supports and the mounting platforms. During operation, the thermosyphons receive heat from the stator and transport it to the mounting platforms whereupon it is convected or radiated to the atmosphere from the aircraft wings. The inner supports have a phase change material received within for providing temporary thermal energy storage during transient conditions.

## Claims

### Claim 1

A passively cooled electromechanical actuator, comprising:
a rotatable rotor including an output shaft;
a stator disposed around said rotor;
a housing containing said rotor and said stator;
a pair of inner supports, each said inner support having a proximal end contacting said stator and a distal end;
a pair of mounting platforms, each one of said mounting platforms contacting one of said distal ends of one of said inner supports;
at least one capillary tube thermosyphon having a plurality of serpentine tubes in thermal communication with said stator, said inner supports and said mounting platforms;
a quantity of phase change material received within each of said inner supports;
an inner thermal conductor disposed between said stator and said thermosyphons; and,
a working fluid received within said thermosyphons.

### Claim 2 (depends on 1)

The electromechanical actuator of claim 1 further including a pair of outer thermal conductors, each one of said outer thermal conductors being disposed between said thermosyphons and one of said mounting platforms.

### Claim 3 (depends on 1)

The electromechanical actuator of claim 1 wherein said phase change material is from the group of acetamide and alkyl hydrocarbons.

### Claim 4 (depends on 3)

The electromechanical actuator of claim 3 wherein said phase change material is acetamide.

### Claim 5 (depends on 1)

The electromechanical actuator of claim 1 wherein said tubes have a diameter of about 1.0 mm to about 2.0 mm.

### Claim 6 (depends on 1)

The electromechanical actuator of claim 1 wherein said thermosyphons are fabricated from aluminum.

### Claim 7 (depends on 1)

The electromechanical actuator of claim 1 further including a multiplicity of legs connecting said housing and said mounting platforms.

### Claim 8 (depends on 1)

The electromechanical actuator of claim 1 wherein said inner thermal conductor is aluminum nitride.

### Claim 9 (depends on 2)

The electromechanical actuator of claim 2 wherein said outer thermal conductors are fabricated from aluminum.