Oil lubricated swashplate

• US 9,260,186 B1
• Filed: 09/07/2011
• Issued: 02/16/2016
• Est. Priority Date: 09/09/2010
• Status: Active Grant

• Current Assignee: Skyworks Global Inc.
• Original Assignee: Groen Brothers Aviation Inc.
• Inventors: van der Westhuizen, Jacob Johannes
• Primary Examiner(s): Sanderson, Joseph W
• Application Number:
  US13/199,712
• Time in Patent Office: 1,623 Days
• US Class Current: 1/1
• CPC Class Codes: B64C 27/025 Rotor drives, in particular for taking off; Combination of autorotation rotors and driven rotors
• CPC Class Codes: B64C 27/18 the means being jet-reaction apparatus
• CPC Class Codes: B64C 27/26 characterised by provision of fixed wings
• CPC Class Codes: B64C 27/605 including swash plate, spider or cam mechanisms
• CPC Class Codes: F01M 5/005 Controlling temperature of lubricant
• CPC Class Codes: F16C 19/525 related to temperature and heat, e.g. insulation
• CPC Class Codes: F16C 2229/00 Setting preload
• CPC Class Codes: F16C 2326/43 Aeroplanes; Helicopters
• CPC Class Codes: F16C 33/667 related to conditioning, e.g. cooling, filtering
• CPC Class Codes: F16C 37/007 of rolling bearings

Abstract

A rotor system for a reactive drive rotary wing maintains the rigidity of the rotor and eliminates play between flight controls and the rotor by mounting swashplate actuators to a flange rigidly secured to the mast. Apparatus and methods perform thermal management of the rotor in order to avoid bearing failure or loss of bearing preload. Methods include modulating the temperature of oil pumped over one or more of the mast bearing, swashplate bearing, and spindle bearing. The temperature of air passively or actively drawn through rotor may also be modulated to maintain bearing temperature within a predetermined range. The rotor includes structures for reducing pressure losses and drag on components due to air flow through the rotor. A rotor facilitates thermal management by oil and air flow.

Claims

1. A method for operating a rotorcraft, the method comprising:

providing the rotorcraft having a rotor, blades, and swashplate, the blades pivoted with respect to the rotor by the swashplate;

receiving oil from a return oil line and pumping oil to a feed line, the feed oil line and return oil line being in fluid communication with a bearing, the bearing being interposed between a rotating ring and a non-rotating ring of the swashplate and comprising a plurality of rolling elements having a preloaded condition within an operating temperature range; and

modulating a temperature of the oil effective to maintain the plurality of rolling elements in the preloaded condition.

2. The method of claim 1, wherein providing a rotorcraft further comprises providing:

the swashplate encircling a mast secured to an airframe of the rotorcraft;

a hub rotatably mounted to the mast, the hub defining a cavity;

the blades pivotably mounted to the hub, each blade defining a duct in fluid communication with the cavity;

the blades, each have a pitch horn secured thereto, the pitch horn being coupled to the rotating ring; and

a shroud encircling the mast, the shroud and mast defining an air channel in fluid communication with the cavity of the hub.

3. The method of claim 2, further comprising:

transmitting compressed air through the air channel into the cavity during takeoff and landing of the rotorcraft, the compressed air having a temperature within the operating temperature range; and

igniting tip jets secured to the blades and in fluid communication with the ducts during takeoff and landing of the rotorcraft.

4. The method of claim 3, further comprising:

impelling the rotorcraft forward in sustained longitudinal flight through air having a temperature lower than the operating temperature range;

modulating the temperature of the oil to maintain the plurality of rolling elements in the preloaded condition by heating the oil during sustained longitudinal flight through air having a temperature lower than the operating temperature range.

5. The method of claim 2, further comprising changing a position of the swashplate to change a collective pitch of the blades.

6. The method of claim 2, further comprising changing the orientation of the swashplate to change a cyclic pitch of the blades.

7. A method for operating a rotorcraft, the method comprising:

providing a rotorcraft having a rotor, blades, and swashplate, each blade having a longitudinal axis and a chord, and the swashplate having a rotating ring and a non-rotating ring separated by a bearing interposed therebetween;

rotating the blades with the rotor;

pivoting each blade, about the longitudinal axis thereof, with respect to the rotor, by the swashplate;

receiving fluid at the bearing, the bearing further comprising a plurality of rolling elements having a preloaded condition within an operating temperature range;

pumping the fluid between a return line and a feed line, wherein the feed line and return line are in fluid communication with the bearing; and

maintaining the preloaded condition of the plurality of rolling elements by modulating a temperature of the fluid to maintain the plurality of rolling elements within the operating temperature range.

8. The method of claim 7, wherein providing a rotorcraft further comprises:

providing the swashplate encircling a mast secured to an airframe of the rotorcraft;

providing a hub rotatably mounted to the mast and defining a cavity;

providing the blades, each pivotably mounted to the hub and defining a duct in fluid communication with the cavity;

providing the blades, each having a pitch horn secured thereto and coupled to the rotating ring; and

providing a shroud encircling the mast to complete with the mast an air channel in fluid communication with the cavity.

9. The method of claim 7, wherein providing the rotorcraft further includes:

providing a mast having proximal and distal ends;

providing a rotor hub rotatably mounted to the mast proximate the distal end;

providing the blades, each having a proximal end, pivotably mounted to the hub, and a pitch horn secured proximate the proximal end thereof;

providing the swashplate encircling the mast and comprising the rotating ring, the non-rotating ring, and the bearing positioned therebetween;

providing the bearing to include the plurality of rolling elements each having a preloaded condition within an operating temperature range;

providing a plurality of pitch control rods coupling the pitch horns to the rotating ring;

providing a plurality of swashplate actuators coupled to the non-rotating ring;

changing the orientation of the non-rotating ring by selectively activating the swashplate actuators; and

maintaining tolerances of the rotating ring and non-rotating ring within an operating range by modulating a temperature of oil passed to the bearing.

10. The method of claim 9, further comprising:

providing the feed line to the bearing;

providing the return line downstream of the bearing;

providing pumping between the return line and the feed line.

11. The method of claim 7, wherein the feed line, return line,

and bearing are part of a closed path for the fluid.

12. The rotor system of claim 7, further comprising:

providing a thermal modulator positioned in thermal contact with the fluid within the closed path; and

providing a control system coupled to the pump and thermal modulator and to activate the thermal modulator;

providing the swashplate, wherein the plurality of rolling elements has the preloaded condition within the operating temperature range; and

controlling, by the control system programmatically activating the thermal modulator, a temperature of the fluid effective to maintain during operation the preloaded condition of the plurality of rolling elements.

13. The method of claim 12, further comprising:

providing a thermal sensor in thermal contact with the fluid within a closed fluid path and having an output electrically coupled to the control system;

controlling, by the control system the temperature of the rolling elements within the operating temperature range according to an output of the thermal sensor.

14. The method of claim 12, further comprising:

providing a compressed air source; and

providing at least one of;

a shroud surrounding the mast to define with the shroud an air channel coupling the compressed air source to the rotor hub, and

an air channel defined by an inner surface of the mast coupling the compressed air source to the rotor hub; and

generating, by the compressed air source, compressed air having a temperature within the operating temperature range.

15. The method of claim 12, further comprising controlling the temperature of the compressed air, by the control system programmed to couple compressed air from the compressed air source to the air channel upon at least one of take off and landing of the rotorcraft on which the rotor system is mounted.

16. The method of claim 12, wherein the thermal modulator comprises one or more of a heating element and a cooling element.

17. The method of claim 7, wherein:

the fluid is oil; and

the rotating and non-rotating rings each define a bearing seat comprising a plurality of oil channels forming a plurality of fluid paths around the bearing.

18. The method of claim 17, further comprising:

passing the oil through a feed port connected to the feed line and a return port connected to the return line, both the feed port and feed line being in direct fluid communication with the plurality of oil channels of the non-rotating ring.

19. The method of claim 7, further comprising:

providing a first upper seal positioned between the rotating and non-rotating rings;

providing a first lower seal positioned between the rotating and non-rotating rings;

positioning the bearing between the first upper seal and first lower seal.

20. The method of claim 19, further comprising:

providing a second upper seal positioned adjacent the first upper seal between the rotating and non-rotating rings; and

providing a second lower seal positioned adjacent the first lower seal between the rotating and non-rotating rings.