Mast main bearing lubrication and thermal management
First Claim
1. A rotor system for a rotary wing aircraft the rotor system comprising:
- a mast secured to an airframe;
a rotor hub rotatably mounted to the mast;
a bearing interposed between the mast and hub, the bearing comprising rolling elements;
a feed oil line and a return oil line in fluid communication with the bearing; and
a pump positioned to move a fluid in a closed fluid path between the feed oil line and return oil linea thermal modulator positioned in thermal contact with fluid within the closed fluid path;
at least one valve within the closed fluid path; and
a control system operably coupled to the valve and thermal modulator and configured to activate one or both of the pump and thermal modulator;
the bearing, wherein the rolling elements have a preloaded condition within an operating temperature range; and
the control system, further programmed to activate the thermal modulator to be effective to maintain the preloaded condition of the rolling elements.
13 Assignments
0 Petitions
Accused Products
Abstract
A rotor system is disclosed for a reactive drive rotary wing aircraft. Rigidity of the rotor is enhanced and play between flight controls and the rotor are eliminated by mounting swashplate actuators to a flange rigidly secured to the mast. Thermal management of the rotor is performed 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. Structures for reducing pressure losses and drag on components due to air flow through the rotor are also disclosed. Thermal management of a rotor may be performed by oil and air flow.
26 Citations
21 Claims
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1. A rotor system for a rotary wing aircraft the rotor system comprising:
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a mast secured to an airframe; a rotor hub rotatably mounted to the mast; a bearing interposed between the mast and hub, the bearing comprising rolling elements; a feed oil line and a return oil line in fluid communication with the bearing; and a pump positioned to move a fluid in a closed fluid path between the feed oil line and return oil line a thermal modulator positioned in thermal contact with fluid within the closed fluid path; at least one valve within the closed fluid path; and a control system operably coupled to the valve and thermal modulator and configured to activate one or both of the pump and thermal modulator; the bearing, wherein the rolling elements have a preloaded condition within an operating temperature range; and the control system, further programmed to activate the thermal modulator to be effective to maintain the preloaded condition of the rolling elements. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for operating a rotary wing aircraft comprising:
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receiving oil from a return oil line and pumping oil to a feed oil line, the feed oil line and return oil line being in fluid communication with a bearing, the bearing being interposed between a mast and a rotor hub, the mast being mounted to an aircraft fuselage and the rotor hub having a plurality of rotor blades secured thereto, the bearing 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. - View Dependent Claims (14, 15)
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16. A rotor assembly for a rotary wing aircraft comprising:
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a mast adapted to secure to an airframe of the aircraft; a rotor hub rotatably mounted to the mast; a bearing interposed between the mast and hub, the bearing comprising rolling elements having a preload within an operating temperature range; a feed oil port and a return oil port in fluid communication with the bearing; a first seal positioned to resist leakage of oil from between the hub and mast; a second seal positioned to resist leakage of oil from between the hub and mast; a shroud surrounding the mast, the mast and shroud defining an air channel; a mast fairing encircling the mast, the mast fairing having a contour effective to reduce pressure losses of air flowing within the air channel; and a mounting ring secured to the hub and mast fairing, the first and second seals being captured between the mounting ring and the mast. - View Dependent Claims (17, 18, 19, 20, 21)
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Specification