Propeller surface area treatments for sound dampening

• US 10,259,574 B2
• Filed: 12/18/2015
• Issued: 04/16/2019
• Est. Priority Date: 12/18/2015
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Beckman, Brian C., Kimchi, Gur, Ko, Allan
• Primary Examiner(s): O'Hara, Brian M
• Application Number:
  US14/975,236
• Publication Number:
  US 20170174338A1
• Time in Patent Office: 1,215 Days
• CPC Class Codes: B64C 11/18 Aerodynamic features
• CPC Class Codes: B64C 11/205 for protecting blades, e.g. coating
• CPC Class Codes: B64C 11/26 Fabricated blades
• CPC Class Codes: B64C 21/10 using other surface properties, e.g. roughness
• CPC Class Codes: B64C 2220/00 Active noise reduction systems
• CPC Class Codes: B64C 2230/14 achieving noise reductions
• CPC Class Codes: B64C 2230/28 at propeller or rotor blades
• CPC Class Codes: B64C 23/06 by generating vortices
• CPC Class Codes: B64U 10/14 with four distinct rotor axes, e.g. quadcopters
• CPC Class Codes: B64U 20/10 for stealth, e.g. reduction of cross-section detectable by radars
• CPC Class Codes: B64U 20/20 for noise reduction
• CPC Class Codes: B64U 20/60 UAVs characterised by the material
• CPC Class Codes: B64U 30/20 Rotors; Rotor supports
• CPC Class Codes: B64U 30/26 Ducted or shrouded rotors
• CPC Class Codes: B64U 30/29 Constructional aspects of rotors or rotor supports; Arrangements thereof
• CPC Class Codes: B64U 50/19 using electrically powered motors
• CPC Class Codes: Y02T 50/10 Drag reduction
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position of one or more propeller blade treatments of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more propeller blade treatments that may be adjusted between two or more positions. Based on the position of the propeller blade treatments, the airflow over the propeller is altered, thereby altering the sound generated by the propeller when rotating. By altering the propeller blade treatments on multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel, reduce, and/or otherwise alter the total sound generated by the aerial vehicle.

Claims

1. An aerial vehicle comprising:

a motor configured to rotate a propeller such that the propeller generates a lifting force;

the propeller including;

a hub that is coupled to the motor so that the motor can rotate the propeller;

a propeller blade extending from the hub, the propeller blade including;

a leading edge;

a tip;

a trailing edge;

a surface area that extends between the hub and the tip and between the leading edge and the trailing edge, the surface area having an upper side and a lower side;

a sound dampening material affixed to at least a portion of the surface area, the sound dampening material configured to absorb and dampen sound from air passing the propeller blade as the propeller blade rotates; and

a plurality of serrations positioned along the leading edge of the propeller blade configured to disrupt air passing the propeller blade;

the sound dampening material configured to absorb at least a portion of a sound generated by the disrupted air.

2. The aerial vehicle of claim 1, wherein the sound dampening material is at least one of a feather, a flocking material, a velvet material, a satin material, a cotton material, a rayon material, a nylon material, a suede material, a synthetic fiber material, a rope, a hemp, or a silk material.

3. The aerial vehicle of claim 1, wherein the surface area includes at least two segments, each segment including a different sound dampening material.

4. The aerial vehicle of claim 1, wherein the sound dampening material covers the upper side of the propeller blade.

5. The aerial vehicle of claim 1, wherein the sound dampening material covers the lower side of the propeller blade.

6. A propeller blade, comprising:

a hub;

a tip;

a surface area that extends between the hub and the tip, the surface area having an upper side, a lower side, a leading edge, and a trailing edge;

a sound dampening material affixed to at least a portion of the surface area of the propeller blade; and

a plurality of serrations positioned along the leading edge of the propeller blade configured to disrupt air passing the propeller blade.

7. The propeller blade of claim 6, wherein:

a first sound dampening material is affixed to the upper side; and

a second sound dampening material is affixed to the lower side.

8. The propeller blade of claim 6, further comprising:

a controller configured to alter a position of a first serration of the plurality of serrations between a first position and a second position, wherein the propeller blade generates a first sound when rotating and the first serration is in the first position and generates a second sound when rotating and the first serration is in the second position.

9. The propeller blade of claim 8, the controller including:

a communication component configured to receive a wireless communication that indicates whether the first serration is to be in the first position or the second position; and

an actuator in contact with the first serration and configured to move the first serration between the first position and the second position based at least in part on the indication included in the wireless communication.

10. The propeller blade of claim 9, further comprising:

a power supply included in the propeller blade and configured to provide power to the actuator.

11. The propeller blade of claim 8, wherein at least some of the plurality of serrations vary in shape and size.

12. The propeller blade of claim 6, wherein the sound dampening material varies over at least a portion of the surface area of the propeller blade.

13. The propeller blade of claim 6, further comprising:

a flexible fringe extending from the trailing edge and configured to disrupt airflow.

14. The propeller blade of claim 13, wherein the flexible fringe is formed of at least one of an elastic material, a carbon composite material, a ceramic material, a porous material, a fabric material, a feather, a fibrous material, a leather material, a fur material, a synthetic material, or a fibrous material.

15. An aerial vehicle, comprising:

a frame;

a first motor coupled to the frame;

a first propeller coupled to and rotatable by the first motor, the first propeller including a first sound dampening material affixed to at least a portion of a surface area of the first propeller such that a sound generated by a rotation of the first propeller is dampened;

a second motor coupled to the frame; and

a second propeller coupled to and rotatable by the second motor, the second propeller including a second sound dampening material affixed to at least a portion of a surface area of the second propeller such that a sound generated by a rotation of the second propeller is dampened;

wherein the first propeller includes a plurality of serrations along a leading edge of the first propeller.

16. The aerial vehicle of claim 15, wherein the first propeller includes a plurality of openings along the surface area.

17. The aerial vehicle of claim 15, wherein the first sound dampening material is affixed to a first portion of the surface area of the first propeller and a third sound dampening material is affixed to a second portion of the surface area of the first propeller.

18. The aerial vehicle of claim 17, wherein:

the first portion is an upper side of the surface area of the first propeller; and

the second portion is a lower side of the surface area of the first propeller.