Electrical apparatus and methods for forming an electrical machine and an electrical apparatus

A method for manufacturing an electrical machine includes forming a plurality of laminations for a stator or a rotor, each lamination including a cooling aperture; stacking the laminations together, the cooling apertures being aligned to form a cooling passage; securing the stacked laminations together; and sealing the laminations together at at least one desired location by applying metal plating to the stacked and secured laminations at the at least one desired location.

TECHNICAL FIELD

The present application relates generally to electrical devices and more particularly, but not exclusively, to an electrical apparatus and methods for forming an electrical machine and an electrical apparatus.

BACKGROUND

Electrical devices remain an area of interest. Some existing systems have various shortcomings, drawbacks and disadvantages relative to certain applications. For example, in some configurations of liquid cooled laminated components, the laminated components may be subject to leaking between laminations. Accordingly, there remains a need for further contributions in this area of technology.

SUMMARY

One embodiment of the present invention is a unique method for manufacturing an electrical machine. Another embodiment is a unique method for manufacturing an electrical apparatus. Another embodiment is a unique electrical apparatus. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for laminated electrical components and machines or apparatuses that employ laminated electrical components. Further embodiments, forms, features, aspects, benefits, and advantages of the present application shall become apparent from the description and figures provided herewith.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

Referring toFIG. 1, some aspects of a non-limiting example of an electrical apparatus10in accordance with an embodiment of the present invention are schematically depicted. In one form, electrical apparatus10is an electrical machine11, e.g., an internal permanent magnet (IPM) motor employing rare earth magnets. In other embodiments, electrical machine11may be an external permanent magnet motor. In still other embodiments, electrical machine11may be another type of permanent magnet motor, an induction motor, a switched reluctance, synchronous reluctance, or permanent magnet assisted reluctance motor, or any other type of motor, generator or motor/generator. In various embodiments, electrical machine11may be a radial flux machine, an axial flux machine or a machine having a three-dimensional (3D) flux path. In one form, electrical machine11is an industrial electrical machine, e.g., an industrial motor. In other embodiments, electrical machine11may not be an industrial electrical machine.

Electrical machine11includes a shaft12, a rotor14having poles16, which as an IPM rotor includes permanent magnets (in other embodiments, rotor14may be constructed as a rotor for various types of electrical machines, for example, permanent magnet machines, induction or synchronous reluctance machines, or other electrical machines, e.g., including but not limited to those listed above, and may or may not include permanent magnets), a stator18having a plurality of stator windings20, a housing22and bearings24. Shaft12and rotor14rotate about an axis of rotation26, which defines an axial direction28. Shaft12rotates with rotor14, and may be considered a part of rotor14. In one form, shaft12is coupled or affixed to rotor14. In other embodiments, shaft12may be integral with rotor14.

Shaft12is constructed to support rotor14and react radial and axial or thrust loads from rotor14. In one form, shaft12is operative to transmit mechanical power from electrical machine11as an output of electrical machine11. In other embodiments, shaft12may be operative to transmit mechanical power to and/or from electrical machine11. Shaft12is axially and radially positioned by bearings24. Shaft12and bearings24define axis of rotation26and corresponding axial direction28.

Rotor14and stator18are in magnetic communication with each other. Rotor14is in magnetic cooperation with stator18to develop torque. Each of rotor14/poles16and stator18have a construction that is operative to direct magnetic flux toward and away from each other. In some embodiments, rotor14may include other operative sources of magnetic flux, e.g., bus bars, windings or both, or other magnetic flux paths, in conjunction with or in place of permanent magnets16, depending on the type of electrical machine10.

In some embodiments, rotor14includes a laminated component15in the form of a laminated rotor core, referred to as laminated rotor core15. A laminated component is a component formed of a plurality of laminations, e.g., a component formed of a plurality of electrical steel laminations. In such embodiments, laminated rotor core15is formed of a plurality of laminations that are stacked and affixed or joined together, and includes cooling passages for liquid cooling of rotor14.

Stator18includes a laminated component30in the form of a laminated stator core, referred to as laminated stator back iron30or laminated stator core30. Laminated stator core30is formed of a plurality of laminations that are stacked and affixed or joined together. Stator windings20are disposed within passages32in laminated stator core30. In one form, stator windings20are copper conductors. In other embodiments, aluminum and/or other conductor materials may be employed in addition to or in place of copper. Stator windings20are constructed for magnetic communication and cooperation with poles16. Stator windings20have overhangs34that extend beyond the ends of stator core30, e.g., extend to the left and to the right of stator core30(in the perspective of the view ofFIG. 1).

Housing22includes an endplate36disposed at one end of housing22and a second endplate38disposed at the other end of housing22. In one form, endplate36is a non-drive end endplate, and endplate38is a drive-end endplate, or pulley endplate. In other embodiments, endplate36may be the drive-end endplate, and endplate38may be the non-drive end endplate. One or both of endplates36and38may be integral with housing22. In some embodiments, housing22also includes a conduit box40, which may or may not be integral, depending upon the embodiment. Other embodiments may not include a conduit box.

Bearings24are constructed to react shaft12and rotor14axial or thrust loads in axial direction28, and to react shaft12and rotor14radial loads perpendicular to axis of rotation26. Housing22is constructed to enclose stator18and react loads associated with stator18, e.g., torque loads and any other loads generated due to magnetic interaction between stator18and rotor14during the operation of electrical machine11. Housing22is also constructed to react thrust loads delivered through bearings24.

In order to increase the power density of electrical machine11, it is desirable to provide cooling, e.g., liquid cooling. Accordingly, embodiments of electrical machine11include provisions for providing liquid cooling of rotor14and/or of stator18. For example, rotor14includes a plurality of cooling passages42extending through laminated rotor core15from one end44of rotor14to the other end46of rotor14. In one form, the cooling passages42are water-cooling passages for passing water therethrough to remove heat from rotor14. In other embodiments, other fluids may be used as heat transfer fluids. Each cooling passage42includes an inlet48for receiving cooling water and an outlet50for discharging the water. Means for delivering the cooling water and for receiving the discharged cooling water are not shown. In the illustration ofFIG. 1, inlet48is disposed at end44; and outlet50is disposed at end46. It will be understood that in various embodiments, inlet48and outlet50may be disposed at any suitable location. The geometry of cooling passages42may vary with the needs of the application. Some embodiments may not include a liquid cooled rotor14.

Similarly, some embodiments include a liquid-cooled stator18. For example, stator18includes a plurality of cooling passages56extending through stator18, e.g., through laminated stator core30. In one form, the cooling passages56are water-cooling passages for passing water therethrough to remove heat from stator18. In other embodiments, other fluids may be used as heat transfer fluids. Cooling passages56may be straight, zig-zag or helical in shape, e.g., a single helical passage wrapping around stator18or a plurality of offset helical passages wrapping around stator18, or may have one or more other shapes. The geometry of cooling passages56may vary with the needs of the application. In the illustrated embodiment, cooling passages56extend from one end58of stator18and laminated stator core30to the opposite end60of stator18and laminated stator core30. Each cooling passage56includes an inlet62for receiving cooling water and an outlet64for discharging the water. Each cooling passage is defined by internal surfaces, e.g., including radially inner surface66and radially outer surface68. Means for delivering the cooling water and for receiving the discharged cooling water (not shown) may vary with the needs of the application. In the illustration ofFIG. 1, inlet62is disposed at end58; and outlet64is disposed at end60. It will be understood that in various embodiments, inlet62and outlet64may be disposed at any suitable location.

Referring also toFIG. 2, some aspects of a non-limiting example of a lamination72for forming a laminated component in the form of laminated stator core30is illustrated in accordance with an embodiment of the present invention. Lamination72includes a plurality of cooling apertures74that form cooling passages56(FIG. 1) when laminations72are stacked together to form laminated stator core30(FIG. 1). Each cooling passage56bridges a plurality of laminations, i.e., extends across a plurality of laminations. Apertures74include walls that form the internal surfaces of cooling passages56, e.g., walls76and78that form respective surfaces66and68of cooling passages56when the laminations72are stacked together to form laminated stator core30. Laminations72include openings80with lands82therebetween that form stator teeth when the laminations72are stacked together to form laminated stator core30. Openings80form passages32in which stator windings20are disposed, and lands82form stator teeth, when laminations72are stacked together to form laminated stator core30.

Laminated stator core30is formed by forming or providing a plurality of laminations72, each lamination including one or more cooling apertures74. The size and geometry of cooling apertures74may vary with the needs of the application. The laminations72are stacked together to form the laminated stator core30, with the cooling apertures74being aligned to form cooling passages56of the desired shape, e.g., straight, zig-zag, helical or other cooling passage shape. The cooling passages56extend at least partially through the laminated component, e.g., laminated stator core30, and in some embodiments extend completely through the laminated component. The stacked laminations72are then secured or fixed together, e.g., temporarily or permanently. For example, the stacked laminations may be clamped together, screwed together using one or more fasteners, welded together or otherwise fixed or secured together.

Each lamination is coated with an insulating material, for example and without limitation, a natural oxide, an enamel, a varnish, or another insulating material. Small gaps or micro-crevices may exist between the laminations, e.g., in the vicinity of cooling passages56. The gaps may be caused by, for example, variations in the thickness of the laminations, variations in the thickness of the insulating material or other manufacturing or assembly related tolerances or variations, minor damage to the laminations or insulation material or other variations. The gaps may lead to leakages between laminations72when cooling liquid is supplied to cooling passages56, e.g., depending upon the applied pressure of the cooling fluid. In many embodiments, water is used as a cooling fluid, e.g., due to its heat transfer properties. However, water can be corrosive and electrically conductive, and it is desirable to prevent leakage through the gaps. Accordingly, it is desirable to seal the gaps.

Referring also toFIG. 3A, laminations72A,72B,72C and72D are illustrated as forming a portion of cooling passage56, in particular radially inner surface66of cooling passage56. Each lamination is coated with a layer of insulating material86. A micro-crevice or gap88, e.g., illustrated as88A and88B, extends between at least some instances of two adjacent laminations. For example, a micro-crevice or gap88A is present between laminations72B and72C. A micro-crevice or gap88B is present between laminations72C and72D. No gap is present between laminations72A and72B. Gap88A is larger than gap88B. In order to prevent leakage of cooling fluid through gaps88, e.g., water, from cooling passage56, the laminations are sealed together at at least one desired location, i.e., at one or more desired locations, by applying metal plating to the stacked and secured laminations at the desired location(s), i.e., depositing the metal layer over the laminations at the desired location(s), e.g., along cooling passage56. The metal plating layer is constructed to seal the gap(s) between adjacent laminations.

For example, as illustrated inFIG. 3B, the at least one desired location is or includes the cooling passage56; and a metal plating90is applied to the laminations72(e.g., the illustrated laminations72A,72B,72C and72D) along the radially inner surface66of the cooling passage, which includes applying the metal plating90over the insulating material86. In one form, the metal plating is electroless nickel plating. In other embodiments, other plating materials may be used with an electroless plating process, e.g., cobalt, copper and/or other materials. In still other embodiments, nickel, cobalt, copper and/or other materials may be used in an electrolytic plating process. The thickness of the plating may vary with the needs of the application. For example, in some embodiments, the plating may have a thickness of approximately 50 μm. In other embodiments, the plating may have a thickness between approximately 40 μm and 60 μm. In other embodiments, the plating thickness may be in the range of approximately 1 μm to 100 μm. In still other embodiments, the plating thickness may be greater or lesser, e.g., up to or greater than 1 mm or less than 1 μm.

In the example ofFIG. 3C, the metal plating, e.g., electroless nickel, is first applied as a thin seed layer94, e.g., having a thickness of approximately 10 μm to 20 μm. The thickness of the seed layer94may vary with the needs of the application. A solder reflow layer96is then applied over the metal plating of seed layer94. Seed layer94provides a metallic surface for solder reflow layer to adhere to. The thickness of solder reflow layer96is much greater than the thickness of seed layer94, and may be, for example, 0.1 mm to 0.3 mm or thicker. The thickness of solder reflow layer96may vary with the needs of the application, and may be thinner or thicker than that mentioned herein. The use of the solder reflow layer96allows a thicker and in some embodiments mechanically stronger sealing layer, and may reduce overall plating time and cost by allowing the use of a thinner metal plating layer, i.e., seed layer94. While still providing the desired sealing effect because of the thicker solder reflow layer96.

In some embodiments, a metal plating layer98, e.g., a thin metal plating layer, e.g., electroless nickel, is applied over the solder reflow layer96, which provides protection of the solder reflow layer from erosion and corrosion and temperature effects, since the nickel plating is less susceptible to erosion and corrosion, and is higher temperature capable than solder reflow layer96. Metal plating layer98may have, for example, a thickness of approximately 0.1 μm to 20 μm. The thickness of the metal plating layer98may vary with the needs of the application, and in some embodiments may be outside this range.

Referring also toFIG. 4A-4B, some aspects of non-limiting examples of the application of a metal plating solution to laminated stator core30is illustrated. The metal plating solution may be any metal plating solution used to provide the desired electroless or electrolytic metal plating. An example of a metal plating solution suitable for providing an electroless nickel plating to a laminated component such as laminated stator core30is Niklad ELV 849 HS, available from MacDermid Inc., of Waterbury, Conn., USA.

In some embodiments, the metal plating, e.g., metal plating90, seed layer94, metal plating layer98and/or other layers or instances of metal plating are applied by immersing all or part of laminated stator core30in a bath of metal plating solution, i.e., immersing one or more desired locations on or within laminated stator core30for sealing by receiving metal plating in the bath of metal plating solution. For example, e.g., as depicted inFIG. 4A, laminated stator core30may be immersed in bath of metal plating solution100disposed in a tank102, with cooling passages56exposed to the metal plating solution. In some embodiments, one or more stirrers and/or agitators and/or solution circulation systems of various types may be employed to ensure that the metal plating solution completely enters and/or fills all desired locations, including gaps and crevices between laminations. In some embodiments, one or more various locations on laminated stator core30may be masked, e.g., using wax, tapes and/or other suitable masking material(s), e.g., to prevent metal plating at such locations.

In some embodiments, the metal plating may be applied to desired locations, e.g., cooling passages56, by passing the metal plating solution, e.g., exclusively, through cooling passages56. For example, e.g., as depicted inFIG. 4B, the metal plating solution100may be disposed in a reservoir108. A pump110may draw metal plating solution100from reservoir108using an inlet tube112, and pump the metal plating solution100through an inlet manifold114into cooling passages56, which may discharge the metal plating solution100through a discharge manifold116back into reservoir108. In some embodiments, the direction of flow of the metal plating solution may be reversed or periodically reversed or the flow may be otherwise agitated in order to ensure that the metal plating solution100reaches the desired locations, and that metal plating is achieved at desired locations, e.g., within cooling passages56, including within micro-crevices or gaps88. In some embodiments, the laminated stator core30can be immersed in a hot bath117(FIG. 4C) of a heat transfer fluid118, e.g., heated by a heating element119, or may be otherwise heated to ensure that a desired plating temperature is achieved, i.e., a desired temperature for performing the plating operation, before and/or during the pumping of the plating chemical solution through the cooling passages56.

In addition to laminated components in the form of a liquid cooled stator core for an electrical machine or a liquid cooled rotor core for an electrical machine, e.g., as described above, in other embodiments of the present invention, the liquid cooled laminated components formed in accordance with the present disclosure may take other forms. For example, with reference toFIGS. 5A and 5B, some aspects of non-limiting examples of laminated components of electrical apparatuses, e.g., liquid cooled laminated components, are schematically illustrated in accordance with embodiments of the present invention.FIG. 5Aillustrates a liquid cooled laminated component in the form of a transformer core120. Cooling passages (not shown) may be disposed at suitable locations within transformer core120.FIG. 5Billustrates a liquid cooled laminated component in the form of an inductor core130, e.g., an inductor core for an electrical reactor or choke. Cooling passages (not shown) may be disposed at suitable locations within inductor core130.

Embodiments of the present invention include a method for manufacturing an electrical machine, comprising: forming a plurality of laminations for a stator or a rotor, each lamination including a cooling aperture; stacking the laminations together, the cooling apertures being aligned to form a cooling passage; securing the stacked laminations together; and sealing the laminations together at at least one desired location by applying metal plating to the stacked and secured laminations at the at least one desired location.

In a refinement, the at least one desired location is the cooling passage, the cooling passage including a surface; the metal plating being applied to the laminations along the surface of the cooling passage.

In another refinement, the metal plating is electroless nickel plating.

In yet another refinement, each lamination is coated with an insulating material; and wherein the metal plating is applied over the insulating material.

In still another refinement, the at least one desired location includes the cooling passage, wherein the applying of the metal plating includes passing the metal plating solution through the cooling passage.

In an additional embodiment, the method further comprises heating the stacked laminations to a desired plating temperature prior to and/or during the passing of the metal plating solution through the cooling passage.

In yet still another refinement, the applying of the metal plating includes immersing the at least one desired location in a bath of metal plating solution.

In a further refinement, the metal plating is applied as a seed layer, further comprising applying solder reflow over the seed layer.

In a yet further refinement, the method further comprises applying additional metal plating over the solder reflow.

Embodiments of the present invention include a method for manufacturing an electrical apparatus, comprising: providing a plurality of laminations for a laminated component of the electrical apparatus, each lamination including a cooling aperture; stacking the laminations together to form the laminated component; aligning the cooling apertures to form a cooling passage extending at least partially through the laminated component; fixing the stacked laminations together; and sealing the laminations to prevent fluid leakage between the laminations from the cooling passage by applying metal plating to the laminations at at least one desired location.

In a refinement, the cooling passage includes an internal surface; the metal plating being applied to the laminations along the internal surface.

In another refinement, the metal plating is electroless nickel plating.

In yet another refinement, each lamination is coated with an insulating material; and wherein the metal plating is applied over the insulating material.

In still another refinement, the at least one desired location including the cooling passage, wherein the applying of the metal plating includes passing the metal plating solution through the cooling passage.

In an additional refinement, the method further comprises immersing the stacked laminations in a heating bath to achieve a desired plating temperature prior to and/or during the passing of the metal plating solution through the cooling passage.

In yet still another refinement, the applying of the metal plating includes immersing the at least one desired location in a bath of metal plating solution.

In a further refinement, the metal plating is applied as a seed layer, further comprising applying solder reflow over the seed layer.

In a yet further refinement, the method further comprises applying additional metal plating over the solder reflow.

In a still further refinement, the laminated component is a stator core for an electrical machine; a rotor core for an electrical machine, a transformer core or an inductor core.

Embodiments of the present invention include an electrical apparatus, comprising: a laminated component including a cooling passage bridging a plurality of laminations, the laminated component having a gap between two adjacent laminations; and a metal plating layer deposited over the laminations along the cooling passage and constructed to seal the gap.

In a refinement, the metal plating is electroless nickel plating.

In another refinement, the electrical apparatus further comprises a solder reflow layer disposed over the metal plating layer, and an additional metal plating layer disposed over the solder reflow layer.