Patent ID: 12187417

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the claimed subject matter to the precise forms disclosed.

Examples of a landing gear assemblies for vehicles are set forth below according to technologies and methodologies of the present disclosure. In an embodiment a landing gear assembly includes an uplock that uses a pair of selectively energized electromagnets. In an embodiment, a landing gear door assembly includes an uplock that uses a pair of selectively energized electromagnets. As will be described in further detail, the electromagnets are configured to provide a fail-secure locking mechanism that maintains the locked state in the event of a power failure. In an embodiment, the polarity of the electromagnets is selectively reversible so that the uplock is capable of providing an attractive force or a repellant force.

While the present disclosure describes various embodiments of retractable landing gear for aircraft, it will be appreciated that the use of such landing gear is not limited to aircraft, and that other implementations, such as on maglev vehicles or any other suitable vehicles, should be considered within the scope of the present disclosure.

FIGS.4and5show an embodiment of a landing gear assembly230in an extended position and a retracted position, respectively. The landing gear assembly230(referred to hereafter as “the landing gear” or “the landing gear230”) is suitable for use with an aircraft220.

The landing gear230shown inFIGS.4and5is similar to the previously described landing gear30ofFIGS.1and2, wherein parts of the landing gear230indicated with reference number2XX correspond to parts of the landing gear30indicated with reference number XX except as otherwise noted. For example, the shock strut232and actuator242shown inFIGS.4and5are similar in form and function to the shock strut32and actuator42, respectively, shown inFIGS.1and2except as noted. For the sake of brevity, components of the landing gear230will not be described again with the understanding that the description of the corresponding component of previously described landing gear30applies.

The landing gear230includes an uplock assembly250that selectively locks the landing gear in the stowed position ofFIG.5. In an embodiment, the uplock assembly250includes a first electromagnet260fixedly mounted within the landing gear bay. That is, the first electromagnet is fixedly positioned relative to the fuselage222of the aircraft, i.e., the body of the vehicle. A second electromagnet270is mounted to a moveable portion of the landing gear230structure. In the illustrated embodiment, the second electromagnet270is coupled to the cylinder236of the shock strut232. In an embodiment, the second electromagnet270is coupled to any suitable portion of the landing gear230.

The first electromagnet260and the second electromagnet270are in operable communication with a controller280. The controller280is programmed to selectively control the polarity and strength of the electromagnetic field produced by each of the first and second electromagnets260and270. As will be explained in further detail, because the polarity and strength of the magnetic fields generated by the electromagnets260and270is selectively varied by the controller280, the electromagnets (1) attract each other to maintain the landing gear230in the stowed position and (2) repel each other when the landing gear begins a deployment motion in order to urge the landing gear toward the extended position.

In some embodiments, the controller280includes a processor and memory. The memory may include computer readable storage media in read-only memory (ROM), random-access memory (RAM), and keep-alive memory (KAM), for example. The KAM may be used to store various operating variables or program instructions while the processor is powered down. The computer-readable storage media may be implemented using any of a number of known memory devices such as PROMs (programmable read-only memory), EPROMs (electrically PROM), EEPROMs (electrically erasable PROM), flash memory, or any other electric, magnetic, optical, or combination memory devices capable of storing data, instructions, programs, modules, etc.

As used herein, the term processor is not limited to integrated circuits referred to in the art as a computer, but broadly refers to a microcontroller, a microcomputer, a microprocessor, a programmable logic controller, an application specific integrated circuit, other programmable circuits, combinations of the above, among others. Therefore, as used herein, the term “processor” can be used to generally describe these aforementioned components, and can be either hardware or software, or combinations thereof, that implement logic for carrying out various aspects of the present disclosure. Similarly, the terms “module” and “unit” can include logic that may be implemented in either hardware or software, or combinations thereof.

In some embodiments, the processor of the controller280executes instructions stored in memory. These instructions may include, for example, a set of algorithms, including resident program instructions stored in one of the storage mediums and executed to provide desired functions. In some embodiments, the set of instructions, when executed by the controller280, carries out, for example, one or more of steps of, and in some embodiments all of the steps of, the method500set forth inFIG.11.

Referring now toFIGS.6and7, embodiments of the first electromagnet260and the second electromagnet270are shown. In an embodiment, the first electromagnet260includes an electrically conductive wire262wound around a ferromagnetic core264to form a solenoid. The conductive wire262receives a flow of electrical current from a power source (not shown) to produce a magnetic field around the solenoid. The polarity of the first electromagnet260is reversible by reversing the direction of the current flowing through the conductive wire262. In addition, the intensity, i.e., strength, of the magnetic field increases and decreases in proportion to the current flowing through the conductive wire. Accordingly, by controlling the direction and power of the electrical current supplied to the electromagnet260, the controller280controls the polarity and strength of the magnetic field generated by the first electromagnet.

The first electromagnet260also includes a permanent magnet266. In an embodiment, the permanent magnet266is integral with the first electromagnet260. In an embodiment, the permanent magnet is separate from but mounted proximate to the first electromagnet260.

Similar to the first electromagnet260, the second electromagnet270includes an electrically conductive wire272wound around a ferromagnetic core274. The second electromagnet270also includes an integral or associated permanent magnet276.

Referring specifically toFIG.6, the uplock assembly250is shown in a locked state. In the locked state, the first electromagnet260is positioned proximate to the second electromagnet270. The controller280controls the current supplied to the first and second electromagnets260and270such that the pole of one of the electromagnets is proximate to the opposite pole of the other electromagnet. That is, the north pole N of the first electromagnet260is proximate to the south pole S of the second electromagnet270or the south pole S of the first electromagnet is proximate to the north pole N of the second electromagnet. The magnetic fields produced by the location and relative polarity of the first and second electromagnets260and270generate a force Fe that attracts the first and second electromagnets to each other.

In the locked position, the permanent magnet266of the first electromagnet260is positioned proximate to the permanent magnet276of the second electromagnet270. Further, the permanent magnets266and276are oriented so that the pole of one of the permanent magnets is proximate to the opposite pole of the other permanent magnet. As a result, the permanent magnets266and276generate a force Fp that attracts the first and second permanent magnets to each other.

The use of the disclosed combination of electromagnets260and270provide a “fail-secure” uplock assembly250. Unlike known fail-safe electromagnet uplocks, fail-secure electromagnetic uplocks continue to secure the landing gear assembly230in the stowed position, even in the event of a failure of one or both electromagnets260and270. Such failures can occur, for example, due to power failure, Foreign Object Damage (FOD), or other circumstances. In the case of the disclosed uplock assembly250, if one or both electromagnets fail, the force Fp generated by the permanent magnets266and276is sufficient to maintain the landing gear in the stowed position. That is, the attractive force Fp between (1) the permanent magnet266fixedly positioned relative to the fuselage and (2) the permanent magnet276fixedly positioned relative to a component of the landing gear is sufficient to maintain the landing gear in the stowed position, even in the absence of any further attractive force Fe of the electromagnets. In the event of uplock electromagnet failure, the landing gear actuator, which is typically hydraulic, is capable of providing sufficient force to overcome the attractive force Fp generated by the permanent magnets266and276. As a result, while the uplock assembly250will retain the landing gear230in the stowed position in the event that one or both electromagnets fail, a pilot is still able to deploy the landing gear.

Referring now toFIG.7, the uplock assembly250is shown in an unlocked state as the landing gear230is beginning to move from the stowed position to the deployed position. To unlock the uplock assembly250, the controller280reverses the current in the coil of one of the electromagnets260or270. In the illustrated embodiment, the current is reversed in the coil272of the second electromagnet270; however, in other embodiments, the current is reversed in the coil262of the first electromagnet260.

Reversing the electrical current in the coil of one of the electromagnets reverses the polarity of that electromagnet. As a result, the pole of one electromagnet is proximate to the same pole of the other electromagnet, i.e., the north poles N of both magnets or the south poles S of both magnets are proximate to each other. The magnetic fields produced by the location and relative polarity of the first and second electromagnets260and270generate a force Fe that repels the first and second electromagnets from each other. This repellent force Fe, alone or in combination with the force of the landing gear actuator(s) is sufficient to overcome the attractive force Fp of the permanent magnets so that the landing gear230is able to move toward the deployed position.

In addition to locking the landing gear230in the stowed position during flight, the disclosed uplock assembly250also provides forces that supplement the actuator242forces that drive the landing gear in both the extension and retraction phases. During landing gear230retraction, the attractive force Fe of the electromagnets260and270pull the landing gear230toward the stowed position during the end of the retraction motion. Conversely, during the initial portion of the landing gear extension, the repellent force Fe of the electromagnets260and270drive the landing gear230toward the deployed position. The supplemental forces provided by the uplock assembly250reduce the actuating force required from the actuator242. As a result, a smaller actuator can be used, which reduces weight as well as space required in the wheel well.

It will be appreciated that the disclosed electromagnets260and270are exemplary only and should not be considered limiting. In this regard, embodiments of the uplock assembly250can include any type of known electromagnets that incorporate permanent magnets and cooperate to provide a fail-secure electromagnetic uplock.

In another embodiment of an uplock, the second electromagnet is replaced by a second permanent magnet, which acts like an armature. When the uplock is locked and the first electromagnet is proximate to the second permanent magnet, the first solenoid and the first permanent magnet are both attracted to the second permanent magnet. When the uplock is switched to an unlocked state, the first solenoid is repelled by the first permanent magnet, while the first permanent magnet remains attracted to the second permanent magnet. Because the repelling force between the first solenoid and the second permanent magnet is greater than the attracting force between the first and second permanent magnets, the first electromagnet is repelled by the second permanent magnet. When the first electromagnet loses power, the attraction force between the first and second permanent magnets is sufficient to maintain function of the uplock until power is restored.

Referring again toFIGS.4and5, a position sensor254is in operable communication with the controller280and is configured to send signals to the controller that correspond to the position of the landing gear230. In an embodiment, the position sensor254is a proximity sensor mounted to the shock strut232and senses a position relative to a target (not shown) mounted within the landing gear bay, to the landing gear, or to any other suitable component. In an embodiment, the position sensor254is a rotary position sensor that measures the angle between two components. In an embodiment, the rotary position sensor measures an angle between the actuator242and the shock strut232, the actuator and a component that is fixed relative to fuselage222, the shock strut and a component that is fixed relative to the fuselage, or any other components for which the relative angle therebetween corresponds to a specific landing gear230position.

In an embodiment, the controller280is programmed to control the uplock assembly250to activate and de-activate according to the position of the landing gear230. In an embodiment, the controller280is further programmed to control the uplock assembly250to activate and de-activate according to whether the landing gear230is extending or retracting. More specifically, the controller280is programmed to energize the electromagnets260and270to provide an attractive force therebetween as the landing gear230approaches the stowed position. In an embodiment, the controller280is programmed to vary the amount of current provided to one or both electromagnets260and270so that the magnitude of the attractive force increases or decreases as the landing gear230approaches the stowed position. In an embodiment, the controller is programmed to de-energize the electromagnets260and270when the landing gear230is moving toward the deployed position and has moved past a predetermined position.

Still referring toFIGS.4and5, an elastic damper252is fixedly mounted within the landing gear bay. When the landing gear230is in the stowed position, the shock strut232or some other suitable landing gear component engages and compresses the damper252. In addition to minimizing potential impact damage as the landing gear230reaches the stowed position, the preload force of the landing gear230against the damper252stabilizes the stowed landing gear to prevent unwanted vibration and chatter during flight.

In an embodiment, an input device256is in operable communication with the controller280. In an embodiment, the input device256is located to enable an operator to send a signal to the controller280manually. In an embodiment, the signal causes the controller280to de-energize, i.e., to disengage the uplock assembly250. In an embodiment, the signal changes one or both electromagnets260and270from a fail-safe mode to a fail-secure mode and vice versa.

FIGS.8and9show an embodiment of a landing gear door assembly300(“door assembly”) similar to the previously described inboard and outboard landing gear doors142and152shown inFIG.3. The door assembly300includes a door302having a panel304rotatably coupled to the aircraft220about an axis306. In an embodiment, the panel304is coupled to the aircraft220by a hinge. In an embodiment, the panel304is coupled to the aircraft220by a linkage or is secured directly to the landing gear. In an embodiment, the panel304does not rotate relative to the aircraft220but instead follows any suitable path as the door assembly300reciprocates between the open position ofFIG.8and the closed position ofFIG.9. When the door assembly300is in the closed position, an inner surface308faces the landing gear bay, and an outer surface310is exposed to the airflow and provides an aerodynamic cover to at least a portion of the landing gear bay.

A drive rod312is rotatably or pivotally coupled to the door302to drive reciprocating motion of the door assembly300between the open and closed positions. In an embodiment, the drive rod312is a portion of or connected to an actuator that drives the motion of the door assembly300. In an embodiment, the drive rod312is coupled to a landing gear component so that extension and retraction of the landing gear drives the motion of the door assembly300. In an embodiment, the drive rod312is coupled to any suitable component or actuator to drive the motion of the door assembly300.

The door assembly300includes an uplock assembly314that has a first electromagnet316fixedly positioned relative to the landing gear bay and a second electromagnet318fixedly coupled to the panel304of the landing gear door302. The first and second electromagnets316and318are in operative communication with a controller380, which is itself in operative communication with an input device356. The uplock assembly314, controller380, and input device356are similar to the uplock assembly250, controller280, and input device256shown inFIGS.4-7.

Similar to the previously disclosed uplock assembly250, the uplock assembly314includes a pair of electromagnets that cooperate to provide a fail-secure means of selectively locking the door302in the closed position when the landing gear is stowed. When the landing gear begins a deployment motion, the uplock assembly250ceases its locking function and provides a force that biases the door302toward the open position.

The door assembly300further includes an elastic bumper320mounted within the cargo bay, to a component of the landing gear, or to any suitable structure. As the door assembly300approaches the closed position, the door panel304contacts the bumper320to react any impact loads without damaging the door panel. When the door assembly300is in the closed position, the door panel304at least partially compresses the bumper320so that the preload of the door panel304against the bumper320prevents unwanted vibration and chatter.

FIG.10shows an embodiment of an aircraft420that includes both of the previously disclosed landing gear assembly230and landing gear door assembly300. In an embodiment, the landing gear assembly230and the landing gear door assembly300share a single controller480, power source458(for the electromagnets), and input device456. In an embodiment, the landing gear door assembly300is considered a part, i.e., a subassembly of, the landing gear assembly230. In an embodiment, one or more of the common components are separate components, each component being associated with one or more of the assemblies. In an embodiment, the aircraft420includes any suitable number of landing gear assemblies230and landing gear door assemblies300that may include common components or separate components that work in conjunction with a single assembly or a subset of assemblies. These and other variations are contemplated and should be considered within the scope of the present disclosure.

Referring now toFIG.11, a representative method500for retracting and extending the landing gear assembly230and landing gear door assembly300ofFIG.10is shown. The method500starts and block502and proceeds to block504.

In block504, the landing gear actuator242begins to retract the extended landing gear assembly230. In an embodiment, retraction of the landing gear assembly230closes the landing gear door assembly300. In an embodiment, a separate actuator retracts to close the landing gear door assembly. The method500then proceeds to block506.

In block506, the controller controls the power source458and electromagnets260and270so that the electromagnets are energized, and attractive forces are generated between electromagnets260and270. The method500then proceeds to block508.

In block508, the controller controls the power source458and electromagnets316and318so that the electromagnets are energized, and attractive forces are generated between electromagnets316and318. The method500then proceeds to block510.

In block510, retraction of the landing gear actuator242ends, and the landing gear assembly230is in the stowed position with the uplock assembly250engaged.

In block512, extension of the landing gear assembly230and landing gear door assembly300begins. The landing gear uplock assembly250is disengaged by reversing a current to one of the landing gear uplock electromagnets, thereby generating a repelling force between electromagnets260and270.

In block514, the landing gear door uplock assembly314is disengaged by reversing a current to one of the landing gear uplock electromagnets, thereby generating a repelling force between electromagnets316and318. The method500then proceeds to block516.

In block516, the landing gear actuator242extends to move the landing gear assembly230toward the deployed position. In an embodiment, extension of the landing gear assembly230opens the landing gear door assembly300. In an embodiment, a separate actuator extends to open the landing gear door assembly300.

In block518, extension of the landing gear actuator242ends when the landing gear assembly230has reached the extended position. The method then proceeds to block520and ends.

It will be appreciated that the disclosed embodiments are exemplary only and should not be considered limiting. In some embodiments, the size, number, position, and actuation of the landing gear and landing gear doors can vary within the scope of the present disclosure. Similarly, the disclosed uplock assemblies can by utilized to secure various embodiments of landing gear and landing gear doors in the stowed/closed positions. These and other variations are contemplated and should be considered within the scope of the present disclosure.

The present application may reference quantities and numbers. Unless specifically stated, such quantities and numbers are not to be considered restrictive, but exemplary of the possible quantities or numbers associated with the present application. Also, in this regard, the present application may use the term “plurality” to reference a quantity or number. In this regard, the term “plurality” is meant to be any number that is more than one, for example, two, three, four, five, etc. The terms “about,” “approximately,” “near,” etc., mean plus or minus 5% of the stated value. For the purposes of the present disclosure, the phrase “at least one of A, B, and C,” for example, means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when greater than three elements are listed.

The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure which are intended to be protected are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure, as claimed.