AU2004237817B2 - Improvements in aircraft landing gear - Google Patents

Abstract

Improvements in Aircraft Landing Gear. A mechanism to achieve forward rotation of aircraft landing wheels prior to landing, plus the option of retardation assistance after landing, incorporating a direct drive electric motor system which is formed integrally within the wheel assembly with a primary electric field being supported on or incorporated within the static components, strut, brake support housing, brake actuating mechanism, torque tube, or a stator in the brake stack of the wheel assembly and the reactive magnetic field being supported on or incorporated within the rotating components of the wheel assembly. Figure 1. figure 2.

Description

1 Complete Specification For The Invention Entitled: IMPROVEMENTS IN AIRCRAFT LANDING GEAR (Magnetically Induced wheel Rotation) The following specification claims an in wheel electric motor drive system with specific reference to aircraft landing wheels which comprise rotational components in proximity to static components (relative to each other). It is known in the field of aircraft wheel assembly design that a common characteristic for most aircraft braking system involves the use of one or more rotor disks in proximity to static friction material (stators in large aircraft) and that said aircraft wheel assembly bear similarity to and interchangeability of design principles with an array of transport vehicles. Those skilled in the art will realize the similarity and the suitability for usage of the in wheel electric motor drive system, herein described and claimed, for a number of transport vehicles, of which an 10 aircraft is also defined as a transport vehicle. Said in wheel electric motor drive system differs markedly from other drive system in that at least one drive component rotational or static will comprise drive materials (Magnetic Field Interactive Materials) bound within said drive components body/matrix. The invention relates primarily to improvements in aircraft landing gear and in wheel electric motor drive systems. These improvements allow controlling of the forward rolling speed of the wheel and tyre assembly just prior to landing, as a primary goal, with a secondary goal relevant to drive and reverse drive, regenerative braking and 20 brake assistance of a load bearing wheel assembly. A primary aim is to adjust an aircraft wheel and tyre assemblies forward rotational speed just prior to landing so as to reduce tyre skidding, reduce impact loading on the landing gear, reduce tyre wear, thus reducing the chance of sudden tyre failure and reducing impact wear and tear on wheels and landing gear. Safety is potentially improved and maintenance costs reduced. A primary objective of the system is to precisely control the forward rotational speed of the aircraft landing wheel- tyre assemblies in relation to the ground speed just prior to 30 landing, by means of an in wheel electric drive system which is contained or partially contained within the wheel and or brake assembly and is either an attachment to such items or forms part of such items during manufacture. This does not necessarily mean that all wheels will spin at a forward rotation rate equal to ground speed at the point of tyre impact with the tarmac, although this rotation speed may be optimum for some aircraft. It may be found desirable to have the landing wheels and thus tyres spinning at a rate either faster, equal to or slower than the rotation rate equivalent to ground speed of the 40 rolling tyre.

2 The optimum rotation speed of the aircraft wheels just prior to landing will be determined by the type of aircraft, the runway pavement condition, dry, wet, icy, hot or cold, the type of pavement and friction characteristics. The optimum wheel rotation speed, for the particular aircraft and runway pavement conditions can be adjusted to afford improved stability of the aircraft under a variety of conditions. The tyre making contact with the runway can have a contact speed differential either faster, slower or equal to the actual ground speed in order to promote stability. 10 The ground speed of the aircraft is already accurately monitored by the aircraft instruments. Wheel rotation rate sensors are already readily available on aircraft brake and brake antiskid systems. These systems are easily modified to register rotation speed which for a known tyre circumference can be converted directly to rolling speed and compared directly with ground speed. The aim is to adjust or fix the rotation rate of the landing wheels either automatically or 20 manually to correspond proportionally faster or slower or equal to ground speed as determined by the optimum for the particular aircraft and pavement conditions. A fixed wheel rotation speed set to a median speed which approximates to the landing speed of a particular aircraft type under most conditions may prove satisfactory and to afford suitable benefits without the complexity of variable speed control. It may also be considered that with present aircraft a certain amount of energy may be absorbed by the normal wheel / tyre impact and skidding on the pavement. This energy absorption may be considered to offer a small amount of braking to the aircraft which 30 would not occure if the wheels are already spinning when pavement contact is made. To counteract this small loss of braking energy the system proposed will offer the option of a form of "regenerative braking" or "reverse drive" which will assist the normal brake system of the aircraft throughout the brake cycle thus more than offsetting the effects of wheel pre-rotation on stopping distances. Said reverse drive would possess similar drive energy capacity to its forward drive capacity since an electric motor is generally equally efficient in forward or reverse drive. Wheel rotation is to be achieved either, electrically, or electro mechanically where by an electric current will create field forces that induce rotation of mechanical components of 40 the wheel assembly at a controlled or predetermined rate of rotation. The wheel assembly shown in figures I and 2 in this instance refers to the wheel rim and wheel support face and the brake stack or heat stack (3) (rotors and stators), the brake actuating components (piston housing) (2) (or electric brake actuator) and the torque tube and strut mounting points for the wheel and brake assembly.

B Present commercial, aircraft, freight aircraft and military aircraft utilise a wheel, tyre, axil, and brake assembly and strut (1) and will be referred to as the landing gear assembly. This landing gear assembly will be improved to incorporate electric field coils, and or electronic components, and or permanent magnets, suitable magnetic material, or magnetic field interactive material such that an imposed electric current will create forward rotation of the wheel tyre assembly due to forces set up between the static and rotating components of the landing gear and wheel and brake assembly. This system can be referred to as a direct drive in wheel electric motor drive system 10 which may be fully or partially contained within the wheel. The static components of the system are the strut (1) which supports all loads including the aircraft weight, the torque tube which absorbs the torque loads from the rotors and stators to the strut. The piston housing or brake actuating components (2) and their support frame (8) are static components, known for the purposes of this application as a "set" of static components. The static components which include the stators static friction material, (brake pads), of the brake stack can be adapted to support or house the primary circuit of the electric 20 motor drive which in the most simplified case would be field windings formed in a circular layout pattern on or attached to one of the static components. These field windings could form a coil around each or some of the brake piston housings (2) Alternatively field windings can be mounted on separate components attached to the brake piston housing support frame (8) or formed onto the brake housing support structure or attached to a stator of the brake stack. 30 The field windings will generally be set out in an even radial pattern of placement around the perimeter of the static support structure. All static components, strut (1), torque tube, brake piston housing (2), brake piston support frame (8), or one of the stators stator disc (brake pad) (9) in the brake stack, can be adapted or manufactured to incorporate or mount a field winding. An electric brake actuator can be used in place of the brake piston housing without alteration to the basic field winding arrangement. Field windings may take the form of a flat armature winding disc which may or may not 40 incorporate an ironless air core and can be attached directly to (or incorporated into) a stator or the brake housing support structure, torque tube or strut. The radius of placement of the static field winding or flat armature will be dependant upon the rotating component on which the static field winding will impose field forces.

4 Rotating components which can interact with the imposed field forces, said components incorporating permanent magnets, suitable magnetic material, inductive material or magnetically 'soft' material all of which can be classified as magnetic field interactive material within magnetic field interactive components, have possible placement locations which include the inner or outer perimeter of the wheel rim. (7) The wheel mounting face (13) or one or more of the rotors in the stator / rotor, brake stack (12). Said rotating components shall for the purposes of this submission be known as a "set" of rotating components wherein rotating components form an alternate "set" of components to the static components while the static components form an alternate set 10 of component to the rotating components. The specification of electric motor type to be used is open to wide variation, since there is a relatively small torque requirement associated with rotating a relatively free spinning aircraft wheel many electric motor types are suitable. A brushless D.C motor with static field windings and high flux density permanent magnets attached radially to and spaced around the perimeter of the rotating component is probably the simplest method of achieving all requirements of torque, and precise rotational speed control. This is one of the layouts described in detail in this document. 20 However Brushless A.C Motor types and A.C Induction Motors with suitable inverter, and or micro processor control will serve the purpose. The rotating componentry of the motor can be permanent magnets set around the wheel rim or as a disc or magnet ring made up of separate magnets attached to a rotor or the wheel mounting face. Toothed blocks of magnetically soft material may replace the magnets as may induction coils or windings depending on the chosen electric motor type to be employed. This material may be attached to or formed into the structure of the rotating component forming part of said components structure embedded or incorporated within the component matrix. There is a very large array of electric motor drive types which can serve the purpose of 30 being incorporated into the aircraft wheel assembly and providing precise forward wheel speed rotation prior to landing and the option of retardation assistance after initial touch down and brake application. The basic component layout of a primary electric field giving rise to induced magnetic fields incorporated on or within for example, the static components of the wheel assembly and an interactive magnetic field due to, permanent magnets being magnetic material or induced in field windings or conductive elements, or electro-magnetically excited material such as inductive material or alternative magnetic field interactive material incorporated on or within for example the rotating components of the wheel 40 assembly, are the basic design criteria. The representative aircraft wheel assembly structure highlights the fact that drawings in the most complex case of an aircraft wheel shows absolutely no clearance rotor to stator thus incorporated magnetic field interactive material in or formed into the structure of a rotating component shall infer the meaning of being part of the structural composition within the matrix of a component.

5 Claims relate to an in wheel electric motor drive system wherein a large array of motor drive types can effectively be incorporated into any wheel assembly which meets the requirements stated as possessing a wheel rim, a hub, at least one rotor disk in proximity to a static friction material, and possessing a static support system, are capable of utilizing this invention. The aim of the claims is not to establish a specific type of electric motor drive type of which an abundant array exist. 10 Brushless DC or AC Motors, DC Servo motors, motor drive systems with a variety of control units can adequately serve the purpose of inducing controlled forward rotation of the aircraft landing wheels and if necessary applying some degree of braking retardation after landing. A primary aim of the claims is to establish a means of adapting well known electric motor drive systems technology to form an in wheel electric motor drive system specifically designed for achieving forward rotation of aircraft landing wheels which it is believed differs markedly from any previous proposals for pre-rotation of aircraft landing wheels. 20 The drawings figure 1 and figure 2 of the drawing page 1/1 show a schematic layout of one of a series of main landing wheels associated with the landing gear typically found on large passenger aircraft. The primary components are similarly numbered on Figures 1 and 2 as are the locations of the incorporated electric motor drive components. For ease of recognition the numbers associated with components or locations on the drawings refer to : 1. Strut Support to landing Gear 30 2. Brake Actuators 3. Brake Stack 4. Wheel Rim 5. Wheel mounting face 6. Tyre 7. Location of Magnetic Flux on wheel rim eg. magnets. 8. Static Brake Support housing 9. Static Stator in Brake Stack. 10. Stator Winding location on Brake Actuator or extension to Actuator or Brake Support Housing. 40 11. Flat Disc Stator Winding located on Brake Support Housing or Brake Stack Stator. 12. Rotor Support Location for Magnet Ring Disc or electro magnetically 'soft' material on Rotor of Brake Stack. 13. Location of Magnet Ring Disc or electro magnetically 'soft' material on inner wheel support face. 14. Location of Flat Disc Armature Winding on brake stack stator.

6 It should be noted that mention is made throughout this specification of incorporating interacting magnetic field producing elements or materials into the structure of a wheel assembly component. The use of statements such as "formed into said components," "formed into the structure of the rotating component," "incorporated within the static components." "manufactured to incorporate," as opposed to "attached to" are a major contributing factor which separate this invention from others. OBJECTIVES, ADVANTAGES, MODE OF OPERATION 10 A primary objective of this invention to create a new and unique in wheel motor drive system which can be used for pre- rotation of aircraft landing wheels which provides the additional benefits of retardation assistance as a result of the imposition of an electrical current applied to specific components of the landing wheel assembly which gives rise to magnetic field forces which interact with reactive magnetic field forces associated with other components within the landing wheel assembly thus giving rise to rotational torque forces and the associated benefits of reduced tire wear and impact loading due to the rotational torque forces allowing controlled pre- rotation of the landing wheels to match the speed of the aircraft at touch down after which the benefits of retardation assistance, or regenerative brake assistance is achieved by the same commonly available 20 circuitry and control units as allow the precise control and monitoring of the forward pre-rotation of the landing wheels. A micro processor link between the aircrafts own computer system monitoring air speed and the A.B.S. brake system, sensors, and circuitry commonly found on most commercial aircraft with an additional link to the electric brake actuation circuitry if used on the aircraft can allow precise speed control of the individual landing wheel pre rotation just prior to landing along with precise control of the brake retardation assistance after touch down. 30 The microprocessors, electrical control units and exact circuitry required do not form part of this invention, all these components and relevant know how are widely available in the market place which includes a vast array of constantly improving technology associated with control units and electric drive technology and drive systems, components of which can be directly applied to manufacture and operate the present invention. The intention of the present invention is to make use of existing and future developments and advances in the theory and principles of electric drive mechanisms, present and future technology in conductor materials, present and future technology in 40 the field of permanent magnets and present and future technology in the field of electric conductor materials which give rise to strong magnetic field forces along with electrical control units and micro processors. All of this technology is available in the market place and components of the technology necessary to manufacture the present invention are easily available with improvements in materials and technology continually coming onto the market.

7 The present invention makes use of existing electric drive system theory and component technology and arranges these components so as to form a new and unique device which can be easily manufactured by persons skilled in the art and can make use of both present and future materials and technology to upgrade and improve the efficiency of the invention while maintaining the basic mode and principles of operation of the present invention. It will be clear to those skilled in the art that the principles associated with an in wheel electric motor drive system referenced in this specification, are directly transferrable to a number of transport vehicle types with similar, wheel, tyre and brake assemblies and in particular cars, buses, trucks and motor cycles. 10 The primary characteristics of the present invention which separate it in terms of novelty and inventiveness from all other prior art results in part from the method of housing the drive system, which is designed to achieve pre-rotation, forward and reverse drive, retardation assistance and regenerative braking of the main load bearing aircraft landing wheels of large commercial airliners wherein the inner wheel is virtually completely filled with brake stack and the inner face of the wheel is almost completely blocked by the brake actuating mechanism, torque tube, and the support structure to which the torque tube and the total assembly is attached. Inspection of the drawings clearly shows the space limitations associated with a typical aircraft main landing wheel assembly, 20 thus requiring incorporation of at least some major drive componentry eg magnetic field interactive material within the body/matrix of a component. The present invention overcomes the problem of space by making the individual components of the drive system a part of the component structure /body/matrix of either or both the static and rotating components of the aircraft landing wheel assembly which forms the housing for the drive components and in so doing totally separates the present invention from all prior art. The ability to also provide a significant and useful amount of retardation assistance or regenerative braking is the result of the high torque characteristics that can be achieved by this present invention and is an added benefit 30 over prior art. The present invention differs greatly from all prior art in the mode and method of operation and construction and provides a new and improved method of pre- rotation and brake retardation assistance for the main landing wheels of commercial, cargo, and other aircraft which is unique, novel and has significant industrial applicability and benefits, which although designed for aircraft should not be considered as exclusive to aircraft as those skilled in the art will know the similarity with other transport vehicles in terms of wheel, tyre and brake assembly and will find the present invention easily applied to such transport vehicles as cars, buses, trucks and similar vehicles utilizing a 40 load bearing wheel assembly with static and rotational components in proximity.

B DESCRIPTION OF THE DRAWINGS The drawings show the rotating wheel and hub assembly of an Aircraft landing wheel assembly, the brake stack assembly of housing, rotors and stators and brake actuating mechanism. The main components that make up the aircraft landing wheel assembly of large commercial aircraft and in particular the set of static components of the brake actuation mechanism the Brake Stack Housing and internal stators (static friction material) an 10 assembly which transfers load to the torque tube and strut of the landing gear all of which represent static components. The set of primary rotating components associated with the aircraft landing wheel assembly are the rotors the inner wheel section, the outer wheel section, and the wheel hub assembly. The Brake Stack consists of rotors which are keyed to the aircrafts wheel and rotate with the wheel and stators which are keyed to the stationary torque tube, which is part of the landing gear structure otherwise known as the aircraft landing wheel assembly, which 20 reacts to torsion and axial loads generated during braking. Rotors and stators are circular disks made of carbon composite or steel which collectively form a cylinder within the brake stack housing otherwise known as heat stack housing. Smaller commercial aircraft often comprise a single brake rotor disk in proximity to a static friction material and brake actuation mechanism, a wheel rim, hub, axil, and support structure similar to that used on an array of transport vehicles. 30 Electrically conductive elements in the form of field windings, or coils or electrically conductive material which give rise to magnetic fields when subjected to an electric current are attached to or incorporated within at least one component of, one set of components either the static or rotating components and form the primary magnetic field components. An adjacent set of components house reactive or secondary magnetic field forces which are created by permanently magnetic material or by conductive elements in the form of suitable magnetically soft material or suitable magnetically soft material enhanced by induction field windings otherwise known as induction coil windings or alternative 40 inductive material in which magnetic fields are induced by the primary magnetic field or by electrically conductive elements which give rise to magnetic field forces due to an imposed electric current, or due to an interaction with the primary magnetic field. The locations of adjacent sets of primary magnetic field components and reactive or secondary magnetic field components are in proximity one to another so as to allow interaction of magnetic field forces.

9 DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to improvements in aircraft landing wheel assembly. These improvements relate specifically to controlling the forward rolling speed of the wheel and tire assembly prior to landing and where required applying added retardation to the wheel after landing. Said motivation and retardation of the wheel can be applied at any appropriate time to assist on ground retardation and or motivation. Regenerative braking energy can be used or stored for future use. Regenerative braking in wheels can be used to provide additional braking in the form of reverse drive. 10 The aim is to adjust the wheel and tire assemblies forward rotational speed prior to landing so as to reduce tire skidding, reduce impact loading on the landing gear, reduce tire wear, thus reducing the chance of sudden tire failure and reducing impact wear and tear on wheels and landing gear. Safety is potentially improved and maintenance costs reduced, while the wheel assembly possesses reverse drive/drive and regenerative braking capabilities. The objective of the system referenced is to precisely control the forward rotational speed of the aircraft landing wheel-tire in relation to the ground speed just prior to 20 landing and applying a degree of retardation assistance after touch down by means of an imposed electric current specifically to induce magnetic field forces located on or within components of the wheel, brake assembly and components of the associated landing gear, such components being contained or partially contained within the wheel and or brake assembly and being either an attachment to such items or forming part of such items during manufacture. Since the wheel assembly comprise a device capable of retardation and forward motivation of a wheel there need not be a restriction on when or where said retardation /motivation is applied as it can be beneficial to both on ground and in air performance of 30 said aircraft./vehicle. It may be found desirable to have the landing wheels and thus tyres spinning at a rate either faster, equal to or slower than the rotation rate equivalent to ground speed of the rolling tire. A fixed wheel rotation speed set to a median speed which approximates to the landing speed of a particular aircraft type under most conditions may prove satisfactory and to afford suitable benefits without the complexity of variable speed control. 40 It may also be considered that with present aircraft a certain amount of energy may be absorbed by the normal wheel assembly impact and tire skidding on the pavement. This energy absorption may be considered to offer a small amount of braking to the aircraft which would not occur if the wheels are already spinning when pavement contact is made. To counteract this small loss of braking energy the system proposed will offer the option of a form of "regenerative braking" or "reverse drive" which will assist the 10 normal brake system of the aircraft throughout the brake cycle thus more than offsetting the effects of wheel pre-rotation on stopping distances. Wheel rotation is to be achieved either, electrically, or electro-mechanically whereby an electric current will create field forces that induce rotation of mechanical components of the wheel assembly at a controlled or predetermined rate of rotation. The wheel assembly in this instance refers to the wheel rim, otherwise described as inner and outer wheel sections, and wheel hub and bearing assembly the brake stack or heat stack containing a brake pack of rotors and stators, the brake actuating components of the 10 piston housing or electric brake actuator the central supporting torque tube and main strut support. Present commercial aircraft and freight aircraft utilize a wheel, tire, axle, and brake assembly which will be referred to as the landing wheel assembly, or wheel assembly in the case of transport vehicles utilizing a similar in wheel electric motor drive system. This landing wheel assembly or wheel assembly will be improved to incorporate electric field coils, and or electrically excited components, which give rise to magnetic fields and shall be referred to as primary magnetic fields, while permanent magnets which can be referred to as permanently magnetic material or alternatively magnetically soft 20 material or inductive material shall be referred to as secondary or reactive magnetic field material since it reacts with the primary magnetic fields, such that an imposed electric current will create forward rotation of the wheel tire assembly due to forces set up between the interaction of magnetic field forces associated with static and rotating components of the landing wheel assembly or wheel assembly, wheel and brake assembly components. This system may be fully or partially contained within the wheel and brake assembly. The static components of the system are the strut which supports all loads including the 30 aircraft weight, the torque tube which absorbs the torque loads from the rotors (brake disks) and stators (brake friction pad material) transferring these loads to the strut., the piston housing or brake actuating components and their support frame plus all stators and support structures and brake stack housing are static components. Either static or rotating components can be adapted to accommodate the primary magnetic field. For ease of understanding of the mode of operation the static components shall be considered to accommodate the primary magnetic field which results from an imposed electric current, Transfer of electric current to static components is easy and considered as part of the preferred embodiment. The rotating components could also receive an 40 electrical current however this would involve slip rings and brushes or commutators thus increasing complexity although the mode of operation is similar and should be considered as an alternative in this invention.

11 The static components can be adapted to support as an attachment or house within said components matrix the primary circuit of the active or primary magnetic field generating medium which in the most simplified case would be field windings on or attached to one of the static components or formed into said component during manufacture. These field windings could be formed as a plurality of individual or linked coils around the outer circumference of a brake actuator or cylindrical field windings forming a thin cylindrical ring around the outer circumference of the brake piston housings and induce 10 magnetic fields which impose reactive forces on interacting magnetic fields associated with components attached to or incorporated into the body/matrix of the inner rim of the rotating wheel in proximity to said field windings. Alternatively primary field windings giving rise to primary magnetic fields can be mounted on components associated with a brake stack housing located in the form of disk shaped field windings, these can be axial flux air gap disk shaped windings and may or may not contain magnetic core material whereby the fields created react with opposing magnetic fields arising from material attached to or formed into rotating components associated with the wheel support face or hub. Another alternative is to 20 attach to or incorporate into said components matrix during manufacture primary field windings into a stator or a static component of the brake stack and brake housing or other static component in proximity and react with a rotor in close proximity which is modified to maintain magnetic fields by incorporating magnetic material, inductive material, soft magnetic material or being formed either partly or completely of an inductive material which may be further reinforced by conductive coils wherein said rotor becomes an inductive body or a magnetic field interactive body interacting with the primary magnetic field and thereby transferring torque forces to the wheel /tyre assembly. A wheel rim or hub may incorporate suitably located and oriented material to allow similar functions to that of the described brake rotor. 30 There are numerous methods for incorporating and integrating magnetic material and magnetic field interactive material into the body/matrix of a component. Said material can be formed into the structure of a component by a wide array of metallurgical techniques commonly utilized by those skilled in the art. One method is to form a rotational component or part of the component from an inductive material, which is acted upon by a primary magnetic field, thereby inducing a secondary magnetic field in the component which thus acts as an induction motor rotor. Another method is to form pieces of magnetic material and or soft magnetic material into the structure of a component during manufacture whereby the material would be located and suitably 40 oriented in a region of the component which is in proximity to a magnetic field with which said material interacts. Standard metal casting techniques or power metallurgy can be used to form matrix material and magnetic field interaction material into an integrated unitary structure.

12 In the simplest case the reactive magnetic field could be high field strength rare earth magnets bonded to, or formed into, embedded into, or otherwise incorporated into the inner rims of the wheel interacting with field coils in proximity and function as a brushless D.C. motor drive system although numerous alternative electric motor drive systems and control units are freely available such as 3 phase synchronous drive systems or brushless A.C. drive systems. The field windings will generally be set out in an even radial pattern of placement around the perimeter or periphery of a static support structure in proximity to the 10 rotating component with which said field windings interact. These items can be easily formed by attaching to or incorporating into the wheel component structure, rare earth or similar high field strength permanent magnets set out in a ring disk formation set into a recess within a disk face or as example of embedment within a component matrix, cylindrical magnets can be embedded into axially aligned cross drilled holes in a rotor disk or alternatively creating a cylindrical formation of an array of separate magnets in proximity to and adjacent to the primary field windings. Alternatively these components could be conducting field windings or magnetically soft segments or such segments enhanced with induction coil windings set into prescribed locations so as to allow an induction field to be set up by a primary current and resultant primary magnetic field 20 thus acting as an induction drive system which can function adequately with a suitable inverter and controller. Numerous drive systems are freely available along with suitable field windings and technology. All static components, strut, torque tube, brake piston housing, brake piston support frame, brake stack and brake housing, or one of the stators in the brake stack can be adapted or manufactured to incorporate or mount a primary field winding. An electric brake actuator can be used in place of the brake piston housing without alteration to the basic field winding arrangement. 30 Field windings may take the form of a flat armature winding disc or a winding of cylindrical form which may or may not incorporate an ironless air core and can be attached directly to a stator or the brake stack housing structure, torque tube or brake support structure, or any one or more of the static components in proximity to the rotational component with which their magnetic fields react. The radius of placement of the static field winding or flat armature will be dependant upon the rotating component on which the static field winding will impose field forces. Rotating components which can interact with the imposed field forces eg. magnetic 40 material such as permanent magnets, or magnetically 'soft' material have possible placement locations which include the inner region of the wheel the outer perimeter of the hub or one or more of the rotors in the brake stack with each plurality of material forming a ring, one or more rotors incorporating magnetic field capabilities interacting with magnetic fields incorporated into a static component in proximity to the rotor can create a very efficient drive system. The specification of electric drive system to be used is open to wide variation, since there is a wide variety of electric drive systems which would suite the purpose. A brushless D.C drive system with static field windings and high flux density permanent magnets embedded in radial locations within and spaced around the perimeter/periphery of the rotating component is probably the simplest method of achieving all requirements of torque, and precise rotational speed control. This is one of the layouts described in detail in this document. However Brushless A.C 10 drive system types and A.C Induction drive systems with suitable inverter, and or micro processor control will serve the purpose. The rotating components of the electric drive system can be magnetic material such as permanent magnets set around the rotating component or as a disk or magnet ring made up of separate magnets magnetic material incorporated within a rotor or the wheel rim or hub. Toothed blocks of magnetically soft material may replace the magnets as may induction coils inductive material or windings depending on the chosen electric drive type to be employed. This material may be attached to or formed into the structure/matrix of the rotating component. Magnetic Material formed into the structure, or incorporated into a component during manufacture creates a permanent magnetic material which is actually part of the component. 20 There is a very large array of electric drive types whereby the basic mode of operation eg. AC induction or DC brushless system or 3 phase synchronous or a wide range of alternatives can serve as the mode of operation of the drive system incorporated into the aircraft or transport vehicle wheel assembly and providing precise forward wheel speed rotation prior to landing and the option of retardation assistance after initial touch down and brake application. Induction motor drive theory, inverters and controllers can be utilized to incorporate induction field windings or inductive material (being material in which a magnetic field 30 is induced by, and interactive with, a primary magnetic field in proximity) into the matrix of stators or other static components or rotors and alternative rotational components thus comprising part of the structure and providing a means of inducing magnetic field forces. Primary magnetic fields can be created in field winding of virtually any shape from flat disks, to cylindrical rings, to complex formed shapes. As mentioned previously an electric current flowing within a field winding or coil gives rise to magnetic field forces however the field winding which gives rise to magnetic 40 field forces can be a conductor forming a field winding integrated or incorporated into the matrix of for instance one or more stator or rotor disk during manufacture which can under the influence of an electric current give rise to magnetic field forces which due to interaction with an adjacent field force in proximity allow the creation of an extremely powerful and reliable mechanism totally suited to the harsh environment of the brake '4 stack. A system which is highly suited to commercial application. One or more rotors can interact with a number of stators or static components in proximity to create a powerful drive mechanism. For the purposes of creating a working model of the present invention a highly efficient model can be fabricated simply by bonding an array of thin permanent magnets into a recess around a median circumference of a rotor or alternatively cross drilling said rotor axially and embedding cylindrical magnets or magnet field interactive material into said radial opposed holes interacting with a field winding disk set into a recess in a stator or 10 end support of the brake stack therein acting as an axial flux motor design utilizing a brushless D.C. Drive System or numerous other drive systems. A working model will be easily created. Alternatively a plurality of thin permanent magnets attached in the form of a cylindrical ring around of an inner wheel rim or embedded within said wheel rim and an adjacent ring of coils or field windings set out as separate coils or a continuous winding with or without iron core, rigidly attached around a perimeter in proximity to the cylindrical ring of magnets and utilizing virtually any brushless drive system from AC, to DC to 3 phase Synchronous drive to name just a few, can give rise to a high torque easily 20 controlled mechanism which is capable of achieving the requirement of pre-rotation and retardation assistance of the aircraft landing wheel assembly or transport vehicle wheel assembly drive and retardation system when used with the correct drive systems and controllers. SUMMARY OF PREFERRED EMBODIMENT It should also be noted that mention is made to the incorporation of primary and reactive magnetic field components into the disk shaped face of a brake stack stator or axial end of the brake stack or brake housing and a reactive field within the face of a rotor. As 30 such a thin disk shaped field winding can be recessed into the face of one or more stators or the end retaining face of the brake stack housing. A disk shaped ring formed by a plurality of magnetic material in the form of permanent magnets can also be set into the face of a brake rotor or alternatively comprise inductive material forming all or forming part of said rotor, thus allowing the drive system to function as a brushless D.C. drive or a 3 phase synchronous drive system an induction drive or a multitude of other drive systems depending on the controller and electric drive technology chosen. 40 Thus In addition to simply recessing the necessary field windings and magnetic material into the disk faces it is also feasible to incorporate these components into the castings or forming during manufacture. It is also feasible to replace the permanent magnets with other types of magnetic material during casting or forming or alternatively to use an A.C. induction drive system and replace the magnetic material with embedded coils or windings or, other inductive material or, magnetically soft material and it is this 15 particular type of embodiment associated with modification, or incorporation of the drive system within the housing, of the brake stack which is considered by the inventor to be the best embodiment of the invention. The alternative embodiments discussed have advantages of ease of construction and can achieve high torque characteristics due the wide radius of actuation and should also be considered highly viable modes of embodiment. Brushless AC, DC, 3 Phase Synchronous drive, or a huge array of electric motor drive theory, inverters, controllers, power and control electronics and new generation 10 magnetic and soft magnetic materials allow components of state of the art electrical machine design to be incorporated into an aircraft landing wheel assembly or transport vehicle wheel assembly as described, to be easily understood and constructed by persons skilled in the field while being totally novel and unlike any other prior invention for achieving the dual benefits of pre-rotation, forward drive and retardation assistance reverse drive and regenerative braking applied to the type of aircraft landing wheel assembly and other wheel assemblies described by this invention. The aim of the claims is not to establish a specific type of electric drive type of which an abundant array exist. Brushless DC or AC Motors, electric drive systems with a variety 20 of control units can adequately serve the purpose of inducing controlled forward rotation of the aircraft landing wheels and other similar wheel assemblies and if necessary applying a degree of braking retardation after landing. The aim of the claims is to establish a means of adapting well known electric motor drive systems technology to form an electric drive system specifically designed for achieving forward rotation of aircraft landing wheels and similar wheel assemblies which differs markedly from any previous proposals for pre-rotation of aircraft landing wheels, and rotation/retardation of wheel assemblies. 30 The drawings figure 1 and figure 2 of the drawing page show the component layout of one of a series of main landing wheels associated with the landing gear typically found on large passenger aircraft. The primary components are numbered on figures 1 and 2 as are the locations of the incorporated electric drive components. Although the present invention comprising an in wheel electric motor drive system is concerned primarily with aircraft wheel assemblies it is also clear that aircraft wheel assemblies are representative and bear similarity to wheel assemblies associated with 40 other transport vehicles, and in some cases light aircraft utilize wheel assembly components, wheels and braking systems which are directly interchange-able with other transport vehicle assemblies.

16 The present invention describes an in wheel electro-magnetic drive system incorporated into a wheel assembly capable of forward and reverse drive, regenerative braking and in the case of main load bearing wheel assemblies, friction brake assistance, which should be considered suitable for use with wheel assemblies equivalent and of similar operational mode which should be considered as suitable for application of the present invention. With respect to the above description the optimum dimensional relationships for the components of the invention, to include variations in size, materials, shape, form, 10 function and the manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those in the drawings and described in the specification are intended to be encompassed by the present invention. Therefore the fore going is considered as illustrative only of the principles of the invention. It is not desired to limit the invention to the exact construction and operation shown and described, thus all suitable modifications and equivalents may be considered to fall within the scope of the invention. 20 Definitions and Meanings Relevant to this Specification Inductive Material Material in which magnetic fields are induced, by a primary magnetic field or by electrically conductive elements which give rise to magnetic field forces resulting from an imposed electrical current. Magnetic Material Material which interacts with a magnetic field or a changing magnetic field, for example permanently magnetic material, and soft magnetic material, and electrically conductive 30 material. Magnetic field Interactive material Material that interacts with a magnetic field in proximity. For example Material sustaining a magnetic field, comprises all material which interacts with a magnetic field due to pre-existing magnetic fields within said material, or a material exhibiting characteristics of being attracted to a magnetic field such as soft magnetic material, or material in which a magnetic field is induced by a primary magnetic field such as inductive materials and electrically conductive materials, thereby possessing the capacity to interact with a magnetic field. 40 Structure For the purposes of this disclosure "structure" shall define something built or constructed.

17 Body A mass making up a component. Integrated To make into a whole by bringing all parts together, becoming part of the component body/structure, thereby acting in unison with said component and within the general alignment/shape/size of said structure/body. Incorporated 10 Shall for the purposes of this disclosure infer the same meaning as integrated. Material Sustaining a Magnetic Field For the purposes of this disclosure said material shall possess magnetic field interactive capabilities due to comprising one or more of permanently magnetic material, inductive material, electrically conductive material, soft magnetic material. Transport Vehicle A vehicle comprising a load bearing wheel/tyre and support system said vehicle being used to "transport" people and equipment examples of which are, but not restricted to; 20 aircraft, cars, trucks, buses, bikes. Matrix For the purposes of this specification "Matrix" of a component shall be defined as a continuous solid phase "body" in which magnetic material, soft magnetic material and or conductive material is embedded or forms part or all of said matrix. A material making up the main body of a component or part of a component "Magnetic Material" embedded, formed into, incorporated into, integrated into, this "Matrix" become part of the component and is not simply an attachment to said component. 30 A set of components For the purposes of this submission rotational components shall be classified as a "Set" of rotational components and static component shall be defined as a "Set" of static component, rotational components being an alternate set of components to the static components and vice-versa.

Claims (20)

1. An in wheel electric motor drive system which utilises components of an aircraft landing gear assembly comprising one or more of; a wheel, a brake system, a strut support, a torque tube; to form a base support medium for electric motor drive components where in electrical components for inducing a primary magnetic fields are at least one of; attached to, incorporated into, static components of the landing gear assembly and reactive components which interact with said primary magnetic field comprise one or more oft a magnetic field interactive material in which a magnetic field is induced by the primary magnetic field, permanent magnets, magnetic material, magnetically soft material, which is incorporated and integrated into the body/matrix of rotating components of the landing gear assembly wherein an interaction between said primary magnetic field and reactive components results in torque forces so as to allow controlled forward rotation of the aircraft landing wheels prior to contact with a runway.

2. The in wheel electric motor drive system of claim 1 whereby an incorporated drive mechanism is formed by a ring shaped formation of separate permanent magnets/magnetic material incorporated and integrated within the circumference of a wheel rim located approximately as shown in Figure 1 item (7) and a series of field winding coils/ stator windings is supported on one or more of; the brake actuating mechanisms (2), piston housing, special extensions of these, the brake support housing (8), located radially and spaced around a perimeter in proximity to said wheel rim circumference, item (10).

3. The in wheel electric motor drive system of claim 1 whereby an incorporated drive mechanism is formed by a ring shaped formation made up of a plurality of permanent magnets /magnetic material incorporated and integrated in radial locations around a rotor (12) of a brake stack, interacting with a stator winding being arranged in a flat disk shape which is attached to at least one of; a brake support housing (11), a torque tube, a stator of a brake pack/stack.

4. The in wheel electric motor drive system of claim 2 whereby the ring shaped formation of permanent magnets/magnetic material incorporated and integrated into the wheel rim at location (7) is replaced by one or more of; inductive material, induction coil windings, field windings, magnetically soft material, incorporated and integrated into, the wheel rim so as to allow the wheel rim to function as a rotating drive component of an induction electric motor whereby the stator winding remains located in position (10) as per claim 2.

5. The in wheel electric motor drive system of claim 3. whereby the ring shaped formation made up of a plurality of permanent magnets /magnetic material is replaced by one or more of; induction coil windings, inductive material, field windings, magnetically soft material, incorporated and integrated in radial locations around a rotor (12) of the brake stack while the stator winding disk remains attached to one of; the brake support housing (11), the torque tube, a stator of the brake pack/stack so as to allow the rotor to function as a rotating drive component of an induction motor.

6. The in wheel electric motor drive system of claim 1 whereby an incorporated drive mechanism is formed by a ring shaped formation of permanent magnets/magnetic material (13) set out in radial locations, incorporated and integrated within a support face/ mounting face of the wheel and interacts with a stator winding supported on at least one of; the torque tube; a stator of the brake stack in close proximity to the wheel mounting face (14).

7. The in wheel electric motor drive system of claim 6 whereby the ring shaped formation of permanent magnets/magnetic material is replaced by at least one of; magnetically soft material, induction coil windings, inductive material.

8. The in wheel electric motor drive system of any one of claims 1, 2, 3, 4, 5, 6 and 7 whereby the motor drive system has an ability to allow forward drive of the landing wheel prior to landing and one or more of; brake assistance, regenerative braking, reverse drive, retardation capacity upon landing to assist primary aircraft brakes.

9. The in wheel electric motor drive system of anyone of claims 1 to 8 linked to a micro computer and or motor drive control unit which is linked to the aircraft computer system and A.B.S. or Antilock Brake system for monitoring aircraft ground speed and wheel rotation rate, and has the ability to automatically adjust forward wheel rotation rate prior to landing and the degree of retardation assistance after landing.

10. An in wheel electric motor drive system for a wheel assembly of a transport vehicle such that an imposed electrical current in electrically conductive material gives rise to primary magnetic fields and such electrically conductive material is at least one of; incorporated into, attached to, at least one static component of the wheel assembly which includes a brake assembly, including rotors and stators of a brake, such that the primary magnetic fields associated forces interact with reactive magnetic field forces originating from material sustaining a magnetic field incorporated and integrated into the body/matrix of rotating components of the wheel assembly, so as to induce rotational forces acting on rotating components creating one of; controlled forward rotation of aircraft landing wheels prior to contact with a runway and controlled retardation assistance after touch down during deceleration of an aircraft; controlled forward rotation and retardation assistance of a transport vehicle wheel assembly.

11. The in wheel electric motor drive system for a wheel assembly of claim 10 wherein a primary magnetic field is electrically induced in a disk shaped field winding incorporated into/attached to, a static housing of a brake stack and reacts with an adjacent magnetic field created by magnetic material incorporated and integrated into a wheel rim including a wheel mounting section and being formed into a disk shaped ring formation incorporated into said wheel rim in proximity to the disk shaped field winding whereby an interaction of magnetic field forces creates rotational forces acting on rotating components of the wheel assembly.

12. The in wheel electric motor drive system for a wheel assembly of claim 10 wherein a primary magnetic field is electrically induced in a disk shaped field winding incorporated into /attached to a static housing of a brake stack /brake support and reacts with an adjacent magnetic field created by at least one of; magnetically soft material, magnetically soft material enhanced by field windings, inductive material, incorporated into at least one rotating component in which a secondary magnetic field is induced by the primary magnetic field of the disk shaped field winding whereby an interaction of magnetic field forces creates rotational forces acting on rotating components of the wheel assembly.

13. The in wheel electric motor drive system for a wheel assembly of claim 10 wherein a primary magnetic field is electrically induced in a series of field windings located around an outer perimeter occupied by a brake actuating mechanism and said primary magnetic field reacts with a magnetic field created by at least one of; a plurality of magnetic material, magnetically soft material in which secondary magnetic fields interact with the primary magnetic field, magnetically soft material enhanced by field windings/inductive material in which secondary magnetic fields are induced by the primary magnetic field, which forms a cylindrical ring incorporated and integrated into a wheel rim in proximity to the primary magnetic field whereby interaction of magnetic field forces gives rise to rotational forces acting on rotating components of the wheel assembly.

14. The in wheel electric motor drive system for a wheel assembly of claim 10 wherein a primary magnetic field is electrically induced in a disk shaped field winding incorporated into/attached to at least one static component of one of; a transport vehicle wheel assembly comprising a brake rotor disk in proximity to a static component, an aircraft landing wheel assembly which includes a brake stack and housing as part of a brake assembly and includes stator disks, whereby one or more rotors providing friction braking in proximity to said static component have a plurality of at least one of; magnetic material, magnetically soft material in which secondary magnetic fields interact with the primary magnetic field, magnetically soft material enhanced by field windings/inductive material in which secondary magnetic fields are induced by the primary magnetic field, forming a disk ring incorporated and integrated into the rotors around a circumference in proximity to the disk shaped field winding of the static component resulting in an interaction of magnetic field forces giving rise to rotational torque forces applied to rotating components of the wheel assembly.

15. The in wheel electric motor drive system for a wheel assembly of claim 10 wherein an imposed electrical current which gives rise to a primary magnetic field is energized within conductive elements being at least one of; a metallic conductor, a non metallic conductor, forming a field winding with at least one of; an air core, a magnetically soft-core, a magnetic core, incorporated into /attached to a static component including stator disks of an aircraft landing wheel assembly wherein said primary magnetic field reacts with a secondary magnetic field induced by the primary magnetic field within a brake rotor disk in proximity to said static component due to an interaction of the primary magnetic field with at least one of; magnetically soft material, magnetically soft material enhanced by field coils, magnetically soft segments, magnetically soft segments enhanced with induction coil windings, inductive material, incorporated and integrated within said brake rotor disk whereby interaction of primary and secondary magnetic field forces creates rotational forces acting on the brake rotor disk.

16. An in wheel electric motor drive system for a wheel assembly comprising a set of rotating components which rotate with a wheel, including a brake rotor used for friction braking, and a set of static components including stators of a brake stack wherein static and rotating components are said to be alternate sets of components such that an applied electrical current applied to conductive material being one of; incorporated into, attached to, at least one component of a set of components gives rise to primary magnetic fields which interact with reactive magnetic fields produced by material sustaining a magnetic field incorporated and integrated into at least one component of an alternate set of components whereby an interaction of magnetic field forces gives rise to rotational forces which act on rotating components of said wheel assembly to induce one of; controlled forward rotation of aircraft landing wheels prior to contact with a runway and controlled retardation assistance during deceleration of an aircraft after touch down with a runway, controlled forward and reverse drive of a transport vehicle wheel assembly.

17. The in wheel electric motor drive system for a wheel assembly of claim 16 wherein a primary magnetic field is electrically induced in a disk shaped field winding incorporated into at least one static component of the wheel assembly which includes a brake assembly which includes one or more of; rotors, stators of a brake stack, static components, while at least one rotor providing friction braking in proximity to the disk shaped field winding has a plurality of at least one of; magnetic material, magnetically soft material in which secondary magnetic fields interact with the primary magnetic field, magnetically soft material enhanced by field windings/inductive material, in which secondary magnetic fields are induced by the primary magnetic field, forming a disk ring incorporated into at least one rotor to form a ring of magnetic field sustaining material in proximity to the disk shaped field winding whereby an interaction of rotational component magnetic fields with those of the primary magnetic field of at least one static component gives rise to rotational torque forces applied to rotating components of the wheel assembly.

18. The in wheel electric motor drive system for a wheel assembly of any one of claims 10 to 17 wherein electrical control of components causing rotational forces and retardation assistance of the wheel assembly are linked to micro processing equipment adapted for monitoring wheel rotation rate in relation to ground speed thereby having the ability to automatically adjust forward wheel rotation rate prior to an aircraft landing and retardation assistance during deceleration after landing.

19. An in wheel electric motor drive system of a transport vehicle wheel assembly wherein static and rotating components are said to be alternate sets of components which includes at least one brake rotor used for friction braking wherein a set of components are stationary components and an alternate set of components are free to rotate in connection with said brake rotor whereby an imposed electrical current in electrically conductive material, being at least one of; attached to, incorporated into, one set of components gives rise to primary magnetic field forces which interact with reactive magnetic field forces associated with elements sustaining a magnetic field incorporated and integrated into at least one component of an alternate set of components wherein said elements are at least one of; magnetic material, magnetically soft material, magnetically soft material enhanced with field windings, inductive material, electrically conductive material, which gives rise to magnetic fields such that rotational forces are created within at least one brake rotor which is in connection with the rotating components of the wheel assembly, to create controlled forward rotation of wheels and controlled retardation assistance during deceleration.

20. The in wheel electric motor drive system of the wheel assembly of claim 19 which contains a set of rotating components and a set of stationary components wherein a primary magnetic field is electrically induced in electrically conductive material which when electrically excited gives rise to magnetic field forces and is at least one of; attached to, incorporated into, at least one component of a stationary component set of the wheel assembly and interacts with magnetic field forces resulting from an imposed electrical current within conductive material incorporated and integrated into a brake rotor of an alternate set of rotational components of the wheel assembly whereby interacting magnetic field forces give rise to rotational torque forces acting on rotational components of the wheel assembly.