Metal plated additively manufactured plastic rotors and their method of manufacturing

A rotor for use in a turbomachine includes a hub centered on a central axis and having a disk portion and a shaft portion and a blade extending outward from the hub. The hub and the blade together include a plastic substrate and metal plating disposed on at least apportion of an outer surface of the plastic substrate. The plastic substrate has a matrix material and fibers embedded in the matrix material. The fibers have a first coefficient of thermal expansion. The metal plating has a second coefficient of thermal expansion. The fibers are selected such that a bulk coefficient of thermal expansion of the plastic substrate at the outer surface of the plastic substrate substantially matches the second coefficient of thermal expansion of the metal plating.

BACKGROUND

The present disclosure relates generally to aviation components and, more particularly, to metal-plated plastic rotors.

Metal-plated plastic aviation components have been developed as a lightweight, high-strength, alternative to metal components. Metal-plated plastic components include a plastic or plastic substrate coated with a metal plating on an outer surface. The metal plating increases the strength and abrasion resistance of the component. Metal-plated plastic components have been particularly attractive for use in gas turbine engine applications, where they can provide overall weight reduction of the engine to improve engine efficiency and provide fuel cost savings.

Limitations in use of metal-plated plastic components include poor adhesion between the metal plating and the plastic substrate, which reduces long-term component durability. Various methods of manufacture and mechanical locking features have been developed to improve an interfacial bond strength between the metal plating the plastic at variable temperatures, as separation of the metal plating can occur.

SUMMARY

In one aspect, a rotor for a turbomachine includes a hub centered on a central axis and having a disk portion and a shaft portion and a blade extending outward from the hub. The hub and the blade together include a plastic substrate and metal plating disposed on at least apportion of an outer surface of the plastic substrate. The plastic substrate has a matrix material and fibers embedded in the matrix material. The fibers have a first coefficient of thermal expansion. The metal plating has a second coefficient of thermal expansion. The fibers are selected such that a bulk coefficient of thermal expansion of the plastic substrate at the outer surface of the plastic substrate substantially matches the second coefficient of thermal expansion of the metal plating.

In another aspect, a method of forming a rotor for a turbomachine includes forming, by an additive manufacturing process, a plastic substrate having an outer surface, impregnating, by the additive manufacturing process, the plastic substrate with fibers having a first coefficient of thermal expansion, and applying a metal plating to the outer surface of the plastic substrate. The metal plating has a second coefficient of thermal expansion and the fibers are selected such that a bulk coefficient of thermal expansion of the plastic substrate at the outer surface of the plastic substrate substantially matches the second coefficient of thermal expansion of the metal plating.

While the above-identified figures set forth embodiments of the present invention, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features, steps and/or components not specifically shown in the drawings.

DETAILED DESCRIPTION

The present disclosure is directed to metal-plated additively manufactured plastic aviation rotor components with controlled thermal expansion behavior to reduce component damage caused by operation in environments of varying temperature or temperature gradients.

FIG.1is a simplified cross-sectional view of a portion of a metal-plated plastic component.FIG.1shows component10, substrate12, matrix14, fibers16, outer surface18, inner region20, outer region22, and metal plating24. Component10can be a rotor component of a turbomachine, including but not limited to an impeller, compressor blade, or turbine blade. Substrate12has outer surface18, inner region20, and outer region22. Outer region22is adjacent to outer surface18. Inner region20is separated from outer surface18by outer region22. Substrate12includes matrix14and fibers16. Fibers16are embedded in matrix14. Metal plating24is disposed on outer surface18of substrate12.

Substrate12includes matrix14and fibers16. Matrix14is a plastic or polymer material. Matrix14can be a thermoplastic. Matrix14can include but is not limited to acrylonitrile butadiene styrene (ABS), polyetherimide (PEI), thermoplastic polyimide, polyether ether ketone (PEEK), polyether ketone (PEKK), polysulfone, polyamide, polyphenylene sulfide, polyester, polyimide, and combinations thereof. Matrix14can define a shape of substrate12. Matrix14can be formed of a plurality of materials with individual materials selectively located in substrate12to provide desired material properties in different regions of component10. In some embodiments, substrate12can include one or more voids or open sections or structures, such as a hollow core or openings formed between internal support structures.

Fibers16are embedded in matrix14. Fibers16are selected and arranged to control a bulk coefficient of thermal expansion (CTE) of substrate12. Fibers16are selected and arranged in substrate12to reduce a CTE mismatch between substrate12and metal plating24. Substrate12with fibers16can be designed to have a bulk CTE substantially matching a CTE of metal plating24to prevent separation of metal plating24from outer surface18during operation of component10in varying temperatures. Fibers16can be selected and arranged to meet additional functional requirements of component10including stress reduction, deflection management, and containment as described further herein.

Matrix14can be formed of a material having a CTE greater than the CTE of metal plating24. Fibers16can be formed of material having a lower CTE than the CTE of matrix14to lower the bulk CTE of substrate12. Fibers16constrain thermal expansion of substrate12. Fibers16can include but are not limited to carbon, metal, para-aramid (e.g., Kevlar® and Twaron®), glass, and combinations thereof. In some embodiments, fibers16can be formed of the same material as metal plating24. In some embodiments, subsets of fibers16can be formed of different materials. Regions of substrate12can include fibers16formed of the same material or different materials. The combinations of materials forming matrix14and fibers16can vary throughout a component to provide desired material properties.

Fibers16can be continuous fibers, discontinuous fibers, or combinations thereof. Fibers16can have a filament diameter and length selected to minimize cracking of substrate12caused by separation at fiber-matrix interfaces. A concentration and arrangement of fibers16can be selected to provide substrate12with a bulk CTE substantially matching the CTE of metal plating24. As shown inFIG.1, fibers16can be substantially uniformly distributed throughout matrix14to provide an entirety of substrate12with a bulk CTE substantially matching the CTE of metal plating24. As discussed further herein, in some embodiments, fiber placement can be tailored to control a bulk CTE of one or more regions of substrate12.

Fibers16can be disposed to extend parallel to outer surface18and metal plating24and/or perpendicular or otherwise angled relative to metal plating24. Fibers16extending perpendicular to otherwise angled relative to metal plating24can extend through outer surface18. Fibers16protruding through outer surface18can improve a bond between metal plating24and substrate12. In some embodiments, a subset of fibers16can be disposed on or at outer surface18. For example, fibers16can form a portion of outer surface18with individual fibers16separated by matrix14. Fibers16disposed at outer surface18or protruding through outer surface18can be formed of a material capable of forming a high-strength bond with metal plating24. Fibers16disposed at outer surface18or protruding through outer surface18can thereby improve a bond between metal plating24and substrate12. For example, fibers16disposed at outer surface18or protruding through outer surface18can be formed of metal. In some embodiments, fibers16and metal plating24can be the same material. In some embodiments, a subset of fibers16formed of metal can be provided to improve bonding of metal plating24, while bulk CTE of substrate12can be controlled primarily by a subset of fibers16formed of another material (e.g., carbon, para-aramid, or glass).

Selection of fiber16material, geometry, orientation relative to metal plating24or outer surface18, and concentration can be made to provide substrate12with an expansion rate in outer region22in a plane parallel to metal plating24not exceeding the expansion rate of metal plating24, while also improving a bond between substrate12and metal plating24. While it is particularly important to control CTE mismatch between substrate12and metal plating24at the interface and an adjacent region to prevent separation of metal plating24, it may not be necessary that all regions of substrate12have the same CTE as discussed further herein. In some embodiments, the composition of both fibers16and matrix14can vary from one region to another. The combination of materials can be selected to provide a desired bulk CTE and other material properties optimized for the operation of component10. Metal plating24is disposed on outer surface18. Metal plating can include but is not limited to chromium-nickel alloys or alloys containing at least one of nickel, cobalt, copper, iron, palladium, chromium, and cadmium. Metal plating24can be selected based on the operational environment of component10and performance requirements of component10, including but not limited to operating temperatures, vibrational impacts, environmental contaminants, impact requirements, etc. Metal plating can have a thickness selected to achieve a desired strength of component10while minimizing the amount of weight metal plating24adds to substrate12. Metal plating can have a thickness, for example, in a range of about 0.001 inches (0.0254 mm) to about 0.050 inches (1.27 mm). It may be desirable to provide metal plating24with a thickness outside of these ranges for some applications. Metal plating can be disposed directly on outer surface18of substrate12. Metal plating24can cover all or portions of outer surface18.

FIG.2is a simplified cross-sectional view of a portion of another embodiment of a metal-plated plastic component.FIG.2shows component30, substrate32, matrix34, fibers36, outer surface38, inner region40, outer region42, and metal plating44. Component30can be substantially similar to component10with the exception of the placement of fibers36. Matrix34and metal plating44can be substantially the same as matrix14and metal plating24of component10shown inFIG.1and described with respect thereto. As described further herein, portions of matrix34can be provided with or without fibers36. For example, some regions of substrate32can be formed of matrix34without fibers36.

Fibers36are embedded in matrix34. Fibers36are selected and arranged to control a bulk coefficient of thermal expansion (CTE) of substrate32, particularly in outer region42and outer surface38. Fibers36are selected and arranged in substrate32to reduce a CTE mismatch between substrate32and metal plating44. Substrate32with fibers36can be designed to have a bulk CTE, particularly in outer region42and at outer surface38, substantially matching a CTE of metal plating44to prevent separation of metal plating44from outer surface38during operation of component30in varying temperatures. As further described herein, fibers36can be selected and arranged to meet additional functional requirements of component30including stress reduction, deflection management, and containment as described further herein.

Fibers36can be arranged in a concentration gradient extending from inner region40to outer surface38with inner region40having a lower concentration of fibers36than outer region42. Inner region40can be defined as a region internal to component30and/or separated from outer surface38. Outer region42is disposed between inner region40and outer surface38and extending to outer surface38. In some embodiments, all or a portion of inner region40can be free of fibers36. The arrangement of fibers36in this manner (i.e., concentration gradient) can produce a variation in CTE of substrate12from inner region40through outer region42, however, the variation in CTE can be tailored to minimize an impact at outer surface38or the bond between metal plating44and substrate32.

Fibers36can include but are not limited to carbon, metal, para-aramid (e.g., Kevlar® and Twaron®), glass, and combinations thereof. In some embodiments, fibers36can be formed of the same material as metal plating44. In some embodiments, subsets of fibers36can be formed of different materials. Regions of substrate32can include fibers36formed of the same material or different materials. The combinations of materials forming matrix14and fiber16can vary throughout a component to provide desired material properties.

Fibers36can be continuous fibers, discontinuous fibers, or combinations thereof. Fibers36can have a filament diameter and length selected to minimize cracking of substrate32caused by separation at fiber-matrix interfaces. A concentration and arrangement of fibers36across inner region40and/or outer region42can be selected to provide substrate32with a bulk CTE at and adjacent to outer surface38substantially matching the CTE of metal plating44. As shown inFIG.2, fibers36can be provided in greatest concentration adjacent to outer surface38.

As described with respect toFIG.1, fibers36can be disposed to extend parallel and/or perpendicular or otherwise angled relative to outer surface38and metal plating44. Fibers36extending perpendicular to otherwise angled relative to metal plating44can extend through outer surface38. Fibers36protruding through outer surface38can improve a bond between metal plating44and substrate32. In some embodiments, fibers36can be disposed on or at outer surface38. For example, fibers36can form a portion of outer surface38with individual fibers36separated by matrix34. Fibers36disposed at outer surface38or protruding through outer surface38can be formed of a material capable of forming a high-strength bond with metal plating44. Fibers36disposed at outer surface38or protruding through outer surface38can thereby improve a bond between metal plating44and substrate32. For example, fibers36disposed at outer surface38or protruding through outer surface38can be formed of metal. In some embodiments, fibers36and metal plating44can be the same material. A subset of fibers36formed of metal can be provided to improve bonding of metal plating44, while bulk CTE of substrate32can be controlled primarily by a subset of fibers36formed of another material (e.g., carbon, para-aramid, or glass).

Selection of fiber36material, geometry, orientation relative to metal plating44or outer surface38, and concentration can be made to provide substrate32with an expansion rate in outer region42in a plane parallel to metal plating44not exceeding the expansion rate of metal plating44, while also improving a bond between substrate32and metal plating44.

FIG.3is a flowchart of a method forming a metal-plated component according to the present disclosure.FIG.3shows method50. Step52includes forming, by an additive manufacturing process, a plastic substrate (e.g., substrate12or32) having an outer surface. The substrate can be formed by 3D plastic printing by depositing a matrix material, such as matrix materials14and34shown inFIGS.1and2and described with respect thereto.

Step54includes impregnating, by the additive manufacturing process, the substrate with fibers. Fibers can be fibers16and36shown inFIGS.1and2and described with respect thereto. As previously described, the fibers can be selected and arranged to provide desired material properties. Fibers can be co-extruded with the matrix material to form the substrate with fibers embedded in the matrix. The addition of fibers to the matrix material produces a substrate with a bulk CTE less than a CTE of the matrix material.

In some embodiments, fibers can be arranged in concentration and/or material gradients as previously described. Fiber arrangement can be controlled by the 3D printing process. In some embodiments, a dual nozzle can be used to extrude materials of different fiber compositions and/or fiber concentrations and selectively print the different material in different regions of the substrate. For example, step54can include selectively printing the fibers in a concentration gradient extending from an inner region of the plastic substrate to the outer surface of the plastic substrate, such that the concentration of fibers increases from the inner region toward the outer surface of the plastic substrate. In other embodiments, step54can include selectively printing the fibers in a region adjacent to the outer surface of the plastic substrate and/or at an angle relative to the outer surface and/or such that fibers protrude through the outer surface of the plastic substrate to improve bonding with a metal plating applied on the outer surface. In some embodiments, step54can include selectively printing the plastic substrate without the fibers (e.g., matrix material only) in an inner region of the plastic substrate.

Step56includes applying a metal plating to the outer surface of the substrate. Metal plating can be metal plating24and44shown inFIGS.1and2and described with respect thereto. The metal plating can be selectively applied to one or more locations on the outer surface (e.g., locations susceptible to damage by abrasion, etc.). The metal plating has a CTE substantially matching the bulk CTE of the substrate or bulk CTE of the substrate in a region adjacent to the outer surface of the substrate in the location metal plating is to be applied. The metal plating can be applied, for example by electroless plating. In some examples, a printer with a dual nozzle can be used to selectively print a catalyst material layer on all or portions of an outer surface of the substrate. For example, one nozzle can extrude the substrate material (matrix and fiber) and one nozzle can extrude the matrix material loaded with a catalyst. The metal plating can then be formed on the outer surface loaded with the catalyst through a process of electroless plating.

FIG.4is a cross-sectional view of a turbomachine.FIG.5is a cross-sectional view of a metal-plated plastic rotor of the turbomachine ofFIG.4formed according to the methods disclosed herein.FIGS.4and5are discussed together herein.

Turbomachine110includes compressor section112and motor section114mounted on tie rod116. Tie rod116is configured to rotate about axis A. Compressor section112includes compressor inlet housing118and compressor outlet housing120that are connected to one another. Motor section114includes motor housing122, which is connected to compressor outlet housing120. Variable diffuser124is positioned between compressor inlet housing118and compressor outlet housing120. Rotor126is positioned between compressor inlet housing118and compressor outlet housing120. Rotor126is mounted on tie rod116, which rotatably connects rotor126and motor section114. Rotor shroud128is positioned radially outward from and partially surrounds compressor rotor126.

Variable diffuser116includes backing plate140, inboard plate142, diffuser vanes144, drive ring146, drive ring bearing148, pinion150, backup ring152, and variable diffuser actuator154. Backing plate140abuts compressor outlet housing120on a first side and inboard plate142on a second side. Inboard plate142abuts backing plate140on a first side and diffuser vanes144on a second side. Diffuser vanes144abut inboard plate142on a first side and rotor shroud128on a second side. Diffuser vanes144are configured to direct the compressed air from rotor126into outlet duct134. Drive ring146is positioned radially outward from rotor shroud128, and drive ring bearing148is positioned between driver ring146and rotor shroud128. Drive ring146abuts rotor shroud128on a first side and backup ring150on a second side. Backup ring150is positioned radially outward of rotor shroud128. Pinion152is connected to variable diffuser actuator154and is coupled to drive ring146. Pinion152permits control of variable diffuser116. Drive ring146is coupled to diffuser vanes144with pins, and as drive ring146is rotated it will drag diffuser vanes144and cause them to rotate.

Motor section114includes motor housing122, motor rotor160, and motor stator162. Motor housing122surrounds motor rotor160and motor stator162. Motor rotor160is disposed within motor stator162and is configured to rotate about axis A. Motor rotor160is mounted to tie rod116to drive rotation of tie rod116.

Motor rotor160of motor section114drives rotation of shafts in turbomachine110, which in turn rotate rotor126. The rotation of rotor126draws air into inlet130of compressor inlet housing118. The air flows through inlet duct132to rotor126and will be compressed by rotor126. The compressed air is then routed through variable diffuser116and into outlet duct134of compressor outlet housing120. The air then exits turbomachine110through outlet136of compressor outlet housing120and can be routed to another component of an environmental control system, such as an air cycle machine.

Turbomachine110further includes first journal bearing170, first rotating shaft172, second journal bearing174, and second rotating shaft176. First journal bearing170is positioned in compressor section112and is supported by compressor outlet housing120. First rotating shaft172extends between and rotates with rotor126and motor rotor160. Motor rotor160drives rotation of rotor126with first rotating shaft172. A radially outer surface of first rotating shaft172abuts a radially inner surface of first journal bearing170. Second journal bearing174is positioned in motor section114and is supported by motor housing122. Second rotating shaft176extends from and rotates with motor rotor160. A radially outer surface of second rotating shaft176abuts a radially inner surface of second journal bearing174.

FIG.5is a cross-sectional view of rotor126positioned in cabin air compressor110.FIG.5shows tie rod116, compressor outlet housing120, rotor126, rotor shroud128, first journal bearing170, and first rotating shaft172of cabin air compressor110. Rotor126includes hub200, blades202, and bore204. Hub200includes first side210, second side212, radially inner end214, radially outer end216, shaft portion218, disk portion220, first flange222, second flange224, and third flange226. As shown inFIG.5, rotor126further includes outer surface240, metal plating241, and fiber-reinforced plastic structure242. Outer surface240is a solid, continuous surface. Outer surface240includes outer surface240A configured to be disposed in a gas path during operation of rotor126. Outer surface240A can include metal plating241. A fiber density of the fibers embedded in the matrix material can vary within the substrate. Fiber-reinforced plastic structure242can include regions of varying fiber density, including first region250, second region252, third region254, fourth region256, fifth region258, sixth region260, seventh region262, and eighth region264in hub200, and ninth region266and tenth region268in blades202. Fiber material and arrangement (e.g., orientation and density) can be selected as previously described to control the bulk CTE of fiber-reinforced plastic structure242and, particularly a CTE of fiber-reinforced plastic structure242in locations of rotor128adjacent to locations where metal plating241is provided to improve a bond between fiber-reinforced plastic structure242and metal plating241. Additionally, fiber density can be increased in regions subject to deflection or increased stress during rotation of rotor126to aid in deflection management and stress reduction. The disclosed regions of varying fiber density are illustrated by lines of varying orientation and spacing. Regions having more closely spaced lines represent regions of higher density. The lines do not indicate an orientation or arrangement of fibers. The disclosed regions of varying density are approximate locations. It will be understood by one of ordinary skill in the art that the density of fibers in any region of rotor126can be based on operating conditions (e.g., speed and temperature) of rotor126in its environment.

Cabin air compressor110has the structure and design as described above in reference toFIG.4. Rotor126is mounted on tie rod116. First flange222of hub200of rotor126forms a labyrinth seal that seals against compressor outlet housing120. As rotor126rotates with tie rod116, the labyrinth seal on first flange222will rotate against compressor outlet housing120, which is a stationary component of cabin air compressor110. Second flange224of hub100of rotor126abuts and rotates with first rotating shaft172. Third flange226of hub200of rotor126abuts and rotates with tie rod116. Third flange226of hub200mounts rotor126to tie rod116. Rotor shroud128is positioned radially outward from rotor126and partially surrounds rotor126.

Rotor126is a metal-plated plastic component formed according to the present disclosure and including a fiber-reinforced matrix (also referred to as “fiber-reinforced plastic structure242”) as disclosed inFIGS.1and2and variations thereof. Fibers can be selected and arranged to control thermal expansion of the plastic component relative to metal plating241and a bulk thermal expansion coefficient of rotor126to manage deflection of rotor126during operation. Fibers can be arranged in increasing fiber density in one or more regions of rotor126to restrain growth of rotor126due to increased temperature during operation. Furthermore, localized increase in fiber density can increase stiffness of rotor126, which can minimize deflection of rotor126. Furthermore, localized increased fiber density can restrain rotor126. Metal plating241can be disposed on one or more portions of rotor126. Metal plating241can provide added strength and improved abrasion resistance of rotor126. Metal plating241can be provided in locations of rotor126most susceptible to abrasion including outer surface240A and seal228. In some embodiments, application of metal plating241can be limited to regions susceptible to damage, such as outer surface240A and seal228to reduce the weight of rotor126. A thickness of metal plating241can vary based on operational requirements of rotor128.

Hub200has seventh region262of fiber-reinforced plastic structure242in first flange222and extending into disk portion220of hub200. Seventh region262is a deflection region of hub200, which is a region of hub200that is subject to deflection during operation of rotor126. As rotor126rotates with tie rod116, first flange222will rotate against compressor outlet housing120and subject seventh region262to deflection. Seventh region262of fiber-reinforced242includes fibers selected and arranged to aid in deflection management during operation of rotor126to reduce and prevent deflection of rotor126. By reducing and preventing deflection during operation of rotor126, the efficiency of cabin air compressor110can be increased. The density of fibers can be increased in seventh region262to control deflection.

Hub100has fifth region258of fiber-reinforced plastic structure242in disk portion220near shaft portion218. Fifth region258is a deflection region of hub200, which is a region of hub200that is subject to deflection during operation of rotor126. As rotor126rotates with tie rod116, fifth region258will be subjected to deflection. Fifth region258of fiber-reinforced242includes fibers selected and arranged to aid in deflection management during operation of rotor126to reduce and prevent deflection of rotor126. By reducing and preventing deflection during operation of rotor126, the efficiency of cabin air compressor110can be increased. The density of fibers can be increased in fifth region258to control deflection.

Blades202have ninth region266and tenth region268of fiber-reinforced plastic structure242. Ninth region266is a region of fiber-reinforced plastic structure242in a portion of blade202extending along disk portion220of hub200. Tenth region268is a region of fiber-reinforced plastic structure242in a portion of blade202extending along shaft portion218of hub200. Ninth region266and tenth region268are deflection regions of rotor126, which are regions of rotor126that are subject to deflection during operation of rotor126. Ninth region266and tenth region268both have increased fiber density compared to second region252, fourth region256, sixth region260, and eighth region264. Blades202are subject to deflection during operation of rotor126and thus have an increase density to prevent deflection of blades202. Tenth region268can also have an increased fiber density compared to ninth region266. Tenth region268is a region of blades202that forms the tips of blades202that are subject to higher deflection. Tenth region268can have a greater fiber density to prevent deflection in the tips of blades202.

There is a gap between blades202of rotor126and rotor shroud128to prevent contact between blades202of rotor126and rotor shroud128. Contact between blades202and rotor shroud128may damage both components and cause failure of cabin air compressor110. The gap between blades202and rotor shroud128has to account for deflection that hub200and blades202of rotor126can be subjected to during operation of rotor126. Thus, the more deformation that hub200and blades202are subjected to during operation of rotor126, the larger the gap needs to be to ensure component safety. However, air can leak from cabin air compressor110through the gap, which leads to inefficiencies in cabin air compressor110. Thus, it is desirable to minimize the gap between blades202of rotor126and rotor shroud128. Identifying deflection regions of hub200and blades202and increasing the fiber density in fiber-reinforced plastic structure242in the deflection regions (for example, fifth region258, seventh region262, ninth region266, and tenth region268) reduces and prevents the deflections and strain that hub200and blades202are subjected to during operation of rotor126by controlling thermal growth and increasing the stiffness in these areas. This reduced deflection and strain and increased stiffness means that the parts deform less when in operation. If hub200and blades202undergo less deflection, the gap between blades202of rotor126and rotor shroud128can be reduced. Reducing the gap increases the efficiency of cabin air compressor110, as more air is forced through rotor126and into variable diffuser124.

Hub200has first region250of fiber-reinforced plastic structure242in second flange224and extending into shaft portion218. First region250is a stress region of hub200, which is a region of hub200that is subject to high stress during operation of rotor126. The high stress in stress regions of rotor126, such as first region250, is a higher stress than stresses present in other regions of rotor126. As rotor126rotates with tie rod216, second flange224will rotate with first rotating shaft172and subject first region250to high stress. First region250of fiber-reinforced plastic structure242is an area of increased fiber density that aids in stress reduction during operation of rotor126to reduce the stress in first region250of hub200. Stress reduction at critical points of hub200leads to increased longevity of rotor126.

Hub200has third region254of lattice structure242in third flange226and extending into shaft portion218. Third region254is a stress region of hub200, which is a region of hub200that is subject to high stress during operation of rotor126. The high stress in stress regions of rotor126, such as third region254, is a higher stress than stresses present in other regions of rotor126. As rotor126rotates with tie rod216, third flange226will rotate with tie rod216and subject third region254to high stress. Third region254of fiber-reinforced plastic structure242is an area of increased fiber density that aids in stress reduction during operation of rotor126to reduce the stress in third region254of hub200. Stress reduction at critical points of hub200leads to increased longevity of rotor126.

Reducing stress in stress regions of rotor126will also improve the longevity of rotor126. Reducing the stresses at stress regions can reduce the failure rate of rotor126as well as the failure rate of cabin air compressor110overall. During operation, these failures can be damage components surrounding rotor126, such as rotor shroud128, as these components are required to contain the energy of the failure for safety of the aircraft and its passengers. Reduced failure rates result in reduced down time, reduced repairs, and reduced costs.

Traditional rotors for rotary machines have solid cross-sections and are manufactured by forging and/or subtractive manufacturing processes, such as hogout. Additively manufacturing can be used to produce fiber-reinforced metal-plated plastic rotor126having a reduced weight compared to traditional rotors while providing abrasion resistance, deflection control, and stress reduction.

Rotor126is one example of a metal plated fiber-reinforced plastic rotor. In alternate embodiments, variations of the disclosed metal-plated fiber-reinforced plastic structure242can be used in any suitable rotor, for example a turbine rotor, having any design. Further, cabin air compressor110is one example of a turbomachinery or rotary machine in which rotor126or any other rotor with metal plated fiber-reinforced plastic structure242or variations thereof can be used.

The disclosed metal-plated plastic rotor components with controlled thermal expansion behavior have an increased durability in environments of varying temperature or temperature gradients. Additional benefits of the disclosed metal-plated components include reduced weight, reduced costs, and faster design, manufacturing, and testing time. Additionally, plastic parts are not prone to static electric charging.

Any relative terms or terms of degree used herein, such as “substantially”, “essentially”, “generally”, “approximately” and the like, should be interpreted in accordance with and subject to any applicable definitions or limits expressly stated herein. In all instances, any relative terms or terms of degree used herein should be interpreted to broadly encompass any relevant disclosed embodiments as well as such ranges or variations as would be understood by a person of ordinary skill in the art in view of the entirety of the present disclosure, such as to encompass ordinary manufacturing tolerance variations, incidental alignment variations, transient alignment or shape variations induced by thermal, rotational or vibrational operational conditions, and the like. Moreover, any relative terms or terms of degree used herein should be interpreted to encompass a range that expressly includes the designated quality, characteristic, parameter or value, without variation, as if no qualifying relative term or term of degree were utilized in the given disclosure or recitation.

Discussion of Possible Embodiments

A rotor for a turbomachine includes a hub centered on a central axis and having a disk portion and a shaft portion and a blade extending outward from the hub. The hub and the blade together include a plastic substrate and metal plating disposed on at least apportion of an outer surface of the plastic substrate. The plastic substrate has a matrix material and fibers embedded in the matrix material. The fibers have a first coefficient of thermal expansion. The metal plating has a second coefficient of thermal expansion. The fibers are selected such that a bulk coefficient of thermal expansion of the plastic substrate at the outer surface of the plastic substrate substantially matches the second coefficient of thermal expansion of the metal plating.

In an embodiment of the rotor of the preceding paragraph the matrix material can have a third coefficient of thermal expansion, the third coefficient of thermal expansion greater than the first coefficient of thermal expansion of the fibers.

In an embodiment of the rotor of any of the preceding paragraphs, the first coefficient of thermal expansion of the fibers can be less than the second coefficient of thermal expansion of the metal plating.

In an embodiment of the rotor of any of the preceding paragraphs, the fibers can be selected from the group consisting of carbon, para-aramid, glass, metal, and combinations thereof.

In an embodiment of the rotor of any of the preceding paragraphs, the metal plating and the fibers can be the same material.

In an embodiment of the rotor of any of the preceding paragraphs, a fiber density of the fibers embedded in the matrix material varies within the plastic substrate.

In an embodiment of the rotor of any of the preceding paragraphs, the plastic substrate can include a first region having a reduced fiber density and one or more second regions having an increased fiber density. The one or more second regions can be a deflection region or a stress region of the rotor. The deflection region is subject to deflections during operation of the turbomachine and the stress region adapted to withstand higher stress than other regions of the rotor during operation of the turbomachine.

In an embodiment of the rotor of any of the preceding paragraphs, the stress region can be a flange extending radially inward from the shaft portion of the hub.

In an embodiment of the rotor of any of the preceding paragraphs, the deflection region can be a flange extending axially outward form the disk portion of the hub.

In an embodiment of the rotor of any of the preceding paragraphs, the deflection region can be in the blade.

In an embodiment of the rotor of any of the preceding paragraphs, the plastic substrate can include an outer region disposed adjacent to the metal coating, the outer region having an increased fiber density.

In an embodiment of the rotor of any of the preceding paragraphs, fibers of the outer region can protrude through the outer surface of the plastic substrate.

In an embodiment of the rotor of any of the preceding paragraphs, fibers of the outer region can be angled with respect to the outer surface of the plastic substrate.

A method of forming a rotor for a turbomachine includes forming, by an additive manufacturing process, a plastic substrate having an outer surface, impregnating, by the additive manufacturing process, the plastic substrate with fibers having a first coefficient of thermal expansion, and applying a metal plating to the outer surface of the plastic substrate. The metal plating has a second coefficient of thermal expansion and the fibers are selected such that a bulk coefficient of thermal expansion of the plastic substrate at the outer surface of the plastic substrate substantially matches the second coefficient of thermal expansion of the metal plating.

The method of the preceding paragraph can optionally include, additionally and/or alternatively, any one or more of the following features, configurations, additional components, and/or steps:

In an embodiment of the method of the preceding paragraph, the additive manufacturing process can be 3D printing.

In an embodiment of the method of any of the preceding paragraphs, the step of impregnating can include selectively printing the fibers to form a region of increased fiber density adjacent to the portion of the outer surface of the plastic substrate to which the metal plating is applied.

In an embodiment of the method of any of the preceding paragraphs, the step of impregnating can include selectively printing fibers at an angle relative to the portion of the outer surface to which the metal plating is applied.

In an embodiment of the method of any of the preceding paragraphs, the plastic of the plastic substrate can have a third coefficient of thermal expansion, the third coefficient of thermal expansion greater than the first coefficient of thermal expansion of the fibers.

In an embodiment of the method of any of the preceding paragraphs, the first coefficient of thermal expansion of the fibers can be less than the second coefficient of thermal expansion of the metal plating.

In an embodiment of the method of any of the preceding paragraphs, the fibers can be selected from the group consisting of carbon, para-aramid, glass, metal, and combinations thereof.