Patent Application
20190276158
A loss-of-lubrication event can cause catastrophic failure of a transmission. For example, if a transmission relies on the circulation of a lubricant to maintain lubrication at an effective operating temperature within the transmission, any failure of that circulatory system will result in increased friction, a rapidly spiking temperature, and eventually seizure of the transmission. Seizure of a transmission on an aircraft while in flight would be catastrophic. Accordingly, precautions must be taken to ensure this does not happen. For this reason, aircraft are currently equipped with backup emergency lubrication systems designed to provide enough extra life to the transmission to enable a safe landing prior to transmission seizure.
While these backup emergency lubrication systems may successfully keep the transmission operating for enough additional time to enable a safe landing, they are not without their disadvantages. For example, they are quite heavy and expensive. These backup emergency lubrication systems generally include a secondary lubricant reservoir filled with additional lubricant, a heater to maintain the additional lubricant at a functional temperature/viscosity, and a secondary pump to circulate the additional lubricant through the transmission. Moreover, these emergency lubrication systems are not fully redundant systems, and therefore, they may not prevent damage to the transmission caused by a loss-of-lubrication event. These backup systems are merely designed to sustain the use of the transmission long enough to enable a safe landing. Accordingly, there is a need for a lighter weight, less expensive, alternative system to sustain a transmission during a loss-of-lubrication event.
In this disclosure, reference may be made to the spatial relationships between various components and to the spatial orientation of various aspects of components as the devices are depicted in the attached drawings. However, as will be recognized by those skilled in the art after a complete reading of this disclosure, the devices, members, apparatuses, etc. described herein may be positioned in any desired orientation. Thus, the use of terms such as “above,” “below,” “upper,” “lower,” or other like terms to describe a spatial relationship between various components or to describe the spatial orientation of aspects of such components should be understood to describe a relative relationship between the components or a spatial orientation of aspects of such components, respectively, as the device described herein may be oriented in any desired direction. In addition, the use of the term “coupled” throughout this disclosure may mean directly or indirectly connected, moreover, “coupled” may also mean permanently or removably connected, unless otherwise stated.
This disclosure divulges an active cooling system for a lubricated component. The active cooling system utilizes convection cooling to remove heat from the lubricated component. The convection cooling can be external or internal to the component. That is, the cooling system can actively direct airflow toward an exterior surface of a housing of the component, or, if the external convection cooling effect is insufficient, the housing of the component may be opened, and airflow directed through the interior of the component for additional cooling.
The active cooling system may, for example, serve as an emergency cooling system for a transmission on an aircraft. In that capacity, the status of a lubrication system of the component is monitored by a sensor. In the event of failure of the lubrication system, the emergency active cooling system may be activated by a pilot in response to a warning provided by the sensor, or the emergency active cooling system may be automatically activated in response to a loss-of-lubrication event. The emergency active cooling system provides emergency cooling by channeling cool air toward the transmission housing and/or into the interior of the transmission so that the cool air may absorb and carry away heat from the transmission.
As shown in
Active cooling system 124 includes a cowling 132 covering proprotor transmission 112. Cowling 132 is configured to protect proprotor transmission 112 from the elements as well as increase the aerodynamic efficiency of aircraft 100. Cowling 132 includes one or more inlet panels 134 that are configured to move from a normal operating position (shown in
Movement of inlet panel 134 from the normal operating position to the cooling position is initiated by an actuator 152. Inlet panel 134 may be biased toward the cooling position and actuator 152 retains inlet panel 134 in the normal operating position until actuator 152 is activated. Inlet panel 134 may be biased open by springs or pneumatic or hydraulic cylinders, for example, arms 150 may be cylinders biasing inlet panel 134 towards the open, cooling position. Actuator 152 may comprise a latch configured to release inlet panel 134 to the biased cooling position. The latch may be an electrical, mechanical, hydraulic, or pneumatic mechanism. The latch may also be an electromagnet wherein loss of current releases inlet panel 134. The latch may also be a memory metal configured to change shape if it reaches a predetermined temperature, wherein the shape change releases inlet panel 134. In this configuration, the memory metal may act as sensor 126 monitoring the temperature and actuator 152 initiating the movement of inlet panel 134. Similarly, actuator 152 may be a thermoplastic component configured to deform beyond a maximum temperature, whereby the deformation releases inlet panel 134. Actuator 152 may also be a pyrotechnic fastener, or explosive bolt, configured to release the biasing force or to act as a jettisoning force. Alternatively, inlet panel 134 may not be biased open. Instead, actuator 152 may comprise an electrical, mechanical, hydraulic, or pneumatic cylinder that does not exert a force until it is activated, and when actuator 152 is activated, it pushes or pulls, inlet panel 134 open.
Cowling 132 may further include one or more outlet panels 154 that are configured to move from a normal operating position (shown in
Movement of outlet panel 154 from the normal operating position to the cooling position may be initiated by an actuator 170. Outlet panel 154 may be biased toward the cooling position and actuator 170 retains outlet panel 154 in the normal operating position until actuator 170 is activated. Outlet panel 154 may be biased open by springs or pneumatic or hydraulic cylinders, for example, arms 168 may be cylinders biasing outlet panel 154 towards the open, cooling position. Actuator 170 may comprise a latch configured to release outlet panel 154 to the biased cooling position. The latch may be an electrical, mechanical, hydraulic, or pneumatic mechanism. The latch may also be an electromagnet wherein loss of current releases outlet panel 154. The latch may also be a memory metal configured to change shape if it reaches a predetermined temperature, wherein the change in shape releases outlet panel 154. In this configuration, the memory metal may act as sensor 126 monitoring the temperature and actuator 170 initiating the movement of outlet panel 154. Similarly, actuator 170 may be a thermoplastic component configured to deform beyond a maximum temperature, whereby the deformation releases outlet panel 154. Actuator 170 may also be a pyrotechnic fastener, or explosive bolt, configured to release the biasing force or to act as the jettisoning force. Alternatively, outlet panel 154 may not be biased open. Instead, actuator 170 may comprise an electrical, mechanical, hydraulic, or pneumatic cylinder that does not exert a force until it is activated, and when actuator 170 is activated, it pushes or pulls, outlet panel 154 open.
External convection cooling of proprotor transmission 112 is accomplished by cool air 148 entering through cowling air inlet 140 and contacting a housing 172 of proprotor transmission 112, heat is then transferred to cool air 148, thereby heating cool air 148 to hot air 166, and then hot air 166 exits through cowling air outlet 158. In order to maximize the heat transfer from housing 172 to cold air 148, housing 172 may include one or more fins 174 extending therefrom to increase the surface area of housing 172. In addition, active cooling system 124 may include ducts within cowling 132 that direct cold air 148 from cowling air inlet 140 directly at optimal portions of housing 172.
The external convection cooling of proprotor transmission 112 may not provide enough cooling to prevent seizure. As such, as shown in
Airflow through the interior of proprotor transmission 112 is created in a similar manner to how airflow through the interior of cowling 132 is created. Housing 172 includes one or more inlet covers 178 that are configured to move from a closed position, wherein the interior of proprotor transmission 112 is sealed off from the outside environment, to an open position, wherein the interior of proprotor transmission 112 is in communication with the outside air. Movement of inlet cover 178 to the open position creates a housing air inlet 180. The open position of inlet cover 178 may be any one of several different possible positions, all of which are configured to increase airflow through housing air inlet 180. For example, inlet cover 178 may include a hinge 182 configured to facilitate rotation of inlet cover 178 away from housing 172. Alternatively, the open position of inlet cover 178 may include inlet cover 178 being jettisoned from aircraft 100 to create housing air inlet 180. In yet another alternative, inlet cover 178 may be attached by a tether 184 coupled to housing 172. In yet another alternative, inlet cover 178 may be made of a thermoplastic material configured to melt when the temperature exceeds a predetermined maximum.
Movement of inlet cover 178 from the closed position to the open position is initiated by an actuator 186. Inlet cover 178 may be biased toward the open position and actuator 186 retains inlet cover 178 in the closed position until actuator 186 is activated. Inlet cover 178 may be biased open by springs or pneumatic or hydraulic cylinders. Actuator 186 may comprise a latch configured to release inlet cover 178 to the biased open position. The latch may be an electrical, mechanical, hydraulic, or pneumatic mechanism. The latch may also be an electromagnet wherein loss of current releases inlet cover 178. The latch may also be a memory metal configured to change shape if it reaches a predetermined temperature, wherein the shape change releases inlet cover 178. In this configuration, the memory metal may act as sensor 126 monitoring the temperature and actuator 186 initiating the movement of inlet cover 178. Similarly, actuator 186 may be a thermoplastic component configured to deform beyond a maximum temperature, whereby the deformation releases inlet cover 178. Actuator 186 may also be a pyrotechnic fastener, or explosive bolt, configured to release the biasing force or to act as the jettisoning force. Alternatively, inlet cover 178 may not be biased open. Instead, actuator 186 may comprise an electrical, mechanical, hydraulic, or pneumatic cylinder that does not exert a force until it is activated, and when actuator 186 is actuated, it pushes or pulls, inlet cover 178 open.
Housing 172 may further include one or more outlet covers 188 that are configured to move from a closed position to an open position. Movement of outlet cover 188 to the open position creates a housing air outlet 190. The open position of outlet cover 188 may be any one of several different possible positions, all of which are configured to increase airflow out of housing 172 through housing air outlet 190. For example, outlet cover 188 may include a hinge 192 configured to facilitate rotation of outlet cover 188 away from housing 172. Alternatively, the open position of outlet cover 188 may include outlet cover 188 being jettisoned from aircraft 100 to create housing air outlet 190. In another alternative, outlet cover 188 may be attached by a tether 194 coupled to housing 172. In yet another embodiment, outlet cover 188 may be made of a thermoplastic material configured to melt when the temperature exceeds a predetermined maximum.
Movement of outlet cover 188 from the closed position to the open position is initiated by an actuator 196. Outlet cover 188 may be biased toward the open position and actuator 196 retains outlet cover 188 in the closed position until actuator 196 is activated. Outlet cover 188 may be biased open by springs or pneumatic or hydraulic cylinders. Actuator 196 may comprise a latch configured to release outlet cover 188 to the biased open position. The latch may be an electrical, mechanical, hydraulic, or pneumatic mechanism. The latch may also be an electromagnet wherein loss of current releases outlet cover 188. The latch may also be a memory metal configured to change shape if it reaches a predetermined temperature, wherein the shape change releases outlet cover 188. In this configuration, the memory metal may act as sensor 126 monitoring the temperature and actuator 196 initiating the movement of outlet cover 188. Similarly, actuator 196 may be a thermoplastic component configured to deform beyond a maximum temperature, whereby the deformation releases outlet cover 188. Actuator 196 may also be a pyrotechnic fastener, or explosive bolt, configured to release the biasing force or to act as the jettisoning force. Alternatively, outlet cover 188 may not be biased open. Instead, actuator 196 may comprise an electrical, mechanical, hydraulic, or pneumatic cylinder that does not exert a force until it is activated, and when actuator 196 is activated, it pushes or pulls, outlet cover 188 open.
It should be understood that inlet covers 178 and outlet covers 188 may be existing access or observation covers of proprotor transmission 112 that have been modified to facilitate the internal convection cooling. Possible additional components of active cooling system 124 may include: fans directing airflow at housing 172 or into housing air inlet 180, compressed gases configured to be released through a nozzle directed at housing 172 or into housing air inlet 180, or a misting system configured to spray a mist or stream of water, or other suitable liquid, on housing 172 to cause evaporative cooling.
While active cooling system 124 is shown and discussed for use with, tiltrotor aircraft 100, active cooling system 124 could be used on any aircraft. As such, the claims appended hereto should not be interpreted as limiting the active cooling system to use on a particular aircraft type unless specifically stated therein. Moreover, while active cooling system 124 is described in conjunction with proprotor transmission 112, it may be used for cooling any aircraft component that may benefit from additional cooling. For example, active cooling system 124 may be used with engine 110, tilt-axis transmission 114, and/or mid-wing transmission 122.
At least one embodiment is disclosed, and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, Rl, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=Rl+k*(Ru−Rl), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 95 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. Also, the phrases “at least one of A, B, and C” and “A and/or B and/or C” should each be interpreted to include only A, only B, only C, or any combination of A, B, and C.
