Magnetic bearing stator with improved coils

Abstract

A stator assembly (10) for a magnetic bearing comprises a core element (12) formed of a ferromagnetic material and having an outer annular portion (22) and a plurality of projections (24) extending radially inward from the outer annular portion (22) and spaced circumferentially about a centerline (LC). A plurality of coils (14) are formed of an electrically insulating material and comprise a first shell half (32) disposed against a first axial end (24a) of a distinct projection among the projections and a second shell half (34) disposed against a second axial end (24b) of the projection (24). The second shell half (34) is coupled to the first shell half (32) such that said projection (24) is enclosed within a cavity (31) defined between the two shell halves.A plurality of windings (16) each comprises at least one wire (17) wound around a coil (14) and capable of being electrically coupled to an electrical power source such that each winding (16) and the projection (24) enclosed by the winding provide a magnetic pole.

Description

Title of the invention: Magnetic bearing stator with improved coils. Technical field of the invention

[0001] The present invention relates to magnetic bearings, and more particularly to stator assemblies for magnetic bearings. Prior art

[0002] Magnetic bearings are known and typically comprise a rotor that is levitated inside an external stator and rotated about a central axis. In active bearings, magnetic poles are produced inside a stator core element by passing an electric current through a plurality of windings. These windings are each generally wound around a coil that electrically isolates the windings from an internal protrusion of the core. Such coils typically take the form of a tubular element having a cavity that is mounted on the protrusions of a core element by sliding the coil radially outward along the protrusion. Summary of the invention

[0003] According to one aspect, the present invention is a stator assembly for a magnetic bearing, the stator assembly comprising a core element formed of a ferromagnetic material, having a midline and an outer annular portion and a plurality of projections. The plurality of projections extend radially inward from the outer annular portion and are circumferentially spaced around the midline, each projection having a first axial end and a second opposing axial end. A plurality of coils are each formed of an electrically insulating material and comprise a first shell half disposed against the first axial end of a projection distinct from the plurality of projections and a second shell half disposed against the second axial end of said projection.The second shell half is coupled to the first shell half such that the protrusion is enclosed within a cavity defined between the first and second shell halves. Furthermore, a plurality of windings each comprises at least one wire wound around a coil distinct from the plurality of coils, each winding being electrically coupled to an electrical power source such that each winding and the protrusion enclosed by the winding provide a pole of the stator.

[0004] According to another aspect, the present invention again relates to a stator-forming assembly as described in the preceding paragraph, but in which each The coil is supplied as a pair of coils. Each pair of coils comprises a pair of first shell halves connected by a first skirt section, each first shell half being positioned against the first axial end of a distinct projection from among two projections in the plurality of projections, and a pair of second shell halves connected by a second skirt section, each second shell half being positioned against the second axial end of a distinct projection from among the two projections. One of the second shell halves is coupled to the first shell half positioned against the same of the two projections to enclose the projection within a cavity defined between the first and second shell halves.The other of the second shell halves is coupled to the other of the first two shell halves positioned against the same of the two projections to enclose the projection within a cavity defined between the first and second shell halves. With this structure, the winding arranged around one coil of each pair of coils and the projection encircled by the winding provide a north pole of the stator, and the winding arranged around the other coil of each pair of coils and the projection encircled by the winding provide a south pole of the stator. Brief description of the figures

[0005] The preceding summary, as well as the detailed description of preferred embodiments of the present invention, will be better understood when read in conjunction with the accompanying drawings. To illustrate the invention, the drawings, which are to scale, show currently preferred embodiments. It should be understood, however, that the present invention is not limited to the specific arrangements and instruments illustrated. In the drawings:

[0006] [Fig.1] is a perspective view of a stator assembly according to the present invention;

[0007] [Fig.2] is a perspective view of the assembly process of a preferred pair of coils on a core-forming element;

[0008] [Fig.3] is a perspective view of the core-forming element with a pair of second housing halves installed;

[0009] [Fig.4] is a perspective view of the core-forming element with a pair of coils installed;

[0010] [Fig.5] is a perspective top and cut-off front view of a winding of the assembly forming the stator;

[0011] [Fig.6] is an interior perspective top view of a preferred pair of the first halves of the case;

[0012] [Fig.7] is an interior perspective view from below of the pair of the first halves of the case;

[0013] [Fig.8] is a cutaway top and side perspective view of a first half of the casing;

[0014] [Fig.9] is a top plan view of the pair of the first halves of the case;

[0015] [Fig. 10] is a bottom plan view of the pair of the first halves of the housing;

[0016] [Fig.1 1] is an interior perspective top view of a preferred pair of the second halves of the case;

[0017] [Fig. 12] is an interior perspective view from below of the pair of second halves of the case;

[0018] [Fig. 13] is a cutaway top and side perspective view of a second half of the casing;

[0019] [Fig. 14] is a top plan view of the pair of second halves of the housing; and

[0020] [Fig. 15] is a bottom plan view of the pair of second halves of the housing. Detailed description of the invention

[0021] Certain terms are used in the following description for convenience only and are not exhaustive. The terms “right,” “left,” “lower,” “upper,” “up,” “down,” and “down” denote directions in the drawings referred to herein. The terms “internal,” “inward,” and “external,” “outward,” refer to directions toward and away from, respectively, a designated midline or geometric center of a described element, the specific meaning being clear from the context of the description. Furthermore, as used herein, the terms “connected” and “coupled” are each intended to include direct connections between two elements without any interposed elements between them and indirect connections between elements in which one or more other elements are interposed between them.The terminology includes the terms specifically mentioned above, their derivatives, and terms of similar scope.

[0022] Referring now to the detailed drawings, in which the same numbers are used to indicate the same elements throughout, Figures 1 to 15 show a stator assembly 10 for a magnetic bearing comprising a housing containing the stator assembly 10, a rotor arranged rotatably inside the stator, and an electrical power source (only the stator is shown). The stator assembly 10 essentially comprises a core element 12 formed of a ferromagnetic material, a plurality of coils 14 formed of an electrically insulating material and a plurality of windings 16 arranged each around a separate coil among the coils 14 so as to provide a plurality of north poles N and a plurality of south poles S ([Fig.1]).

[0023] Referring first to Figures 1 to 4, the core-forming element 12 has a midline Lc ([Fig. 2]) and comprises an external annular portion 22 and a plurality of projections 24 extending radially inward from the external annular portion and spaced circumferentially around the midline Lc. The external annular portion 22 has opposing first and second axial ends 22a, 22b, a plurality of internal circumferential surface sections 23A extending between each pair of adjacent projections 24, and an external circumferential surface 23B. In addition, each projection 24 has a first axial end 24a, a second axial end 24b opposite, a free internal radial end 25a and an external radial end 25b formed as a single piece with the annular part 22.Preferably, each projection 24 has generally rectangular cross-sections and has opposing first and second circumferential sides 24c, 24d extending axially between the first and second axial ends 24a, 24b. Most preferably, the two circumferential sides 24c, 24d converge towards each other in one direction from the outer radial end 25a to the inner radial end 25b so that each projection 24 is generally wedge-shaped. Furthermore, the core-forming element 12 is preferably formed by a single stamping or laser cutting of thin sheets of silica steel that are bonded together to form the complete core-forming element 12.

[0024] Referring now to Figures 1, 2, and 5, each coil 14 is arranged around a distinct projection among the plurality of projections 24 of the core-forming element and has an internal radial end 14a adjacent to an internal radial end 25a of the enclosed projection 24 and an external radial end 14b adjacent to the external radial end 25b of the enclosed projection 24. Each coil 14 is formed of two parts or segments 30A, 30B, preferably two shell halves 32, 34, which are assembled together axially around a distinct projection among the projections 24 as described in detail below. More specifically, each coil 14 comprises a first segment 30A or a first half of a shell 32 disposed against the first axial end 24a of a distinct projection among the plurality of projections 24 and a second segment 30B or a second half of a shell 34 disposed against the second axial end 24b of said projection 24.The second segment 30B / the second half of the hull 34 is coupled to the first segment 30A / to the first half of the hull 32 so that said projection 24 is enclosed within a cavity 31 defined between the first and second halves of the hull 32, 34. The most. Preferably, each first shell half 32 is provided in the form of a pair 33 of first shell halves 32 and each second shell half 34 is provided in the form of a pair 35 of second shell halves 34, so that each pair 33, 35 of shell halves 32, 34 provides two coils 14, as described in detail below. Furthermore, each coil 14 is preferably formed of a polymer material, such as nylon, polyetherimide (PEI), acrylonitrile butadiene styrene (ABS), polyetheretherketone (PEEK), etc.

[0025] With reference to Figures 1 and 5, the plurality of windings 16 each comprise at least one wire 17 wound around a coil separate from the plurality of coils 14 so as to extend circumferentially around the coil 14 and radially between the inner end 14a of the coil and the outer end 14b of the coil.Preferably, the wire winding is carried out by an automated process, most preferably a needle winding, but it can alternatively be wound manually. In all cases, each winding 16 is electrically coupled to an electrical power source (not shown) such that each winding 16 and the projection 24 enclosed by the winding 16 provide an N or S pole of the stator assembly 10, while each coil 14 prevents electric flux between the winding 16 and the enclosed projection 24. Preferably, each winding 16 is designed and electrically connected to an adjacent winding 16 such that one winding 16 produces a north pole N while the adjacent connected winding 16 produces a south pole S, and a magnetic flux passes in a circuit between the N, S, and S poles shown in [Fig. 1].Thus, with the preferred pairs 33, 35 of shell halves 32, 34, each pair 15 of coils 14 thus formed is designed to provide mounting surfaces for both the windings 16 and the connecting wires for a pair of complementary north and south poles N, S, while electrically isolating the two windings 16 from the enclosed projections 24. In a currently preferred embodiment, the pairs 15 of coils 14 and the windings 16 are arranged and designed (e.g., electrically connected) to provide a north pole N and south pole S arrangement in an NSSNNSSN pattern following a clockwise rotation around the stator assembly 10, as shown in [Fig. 1].

[0026] By equipping the coils 14 with a two-part structure as described above and in more detail below, the installation of the coils 14 onto the projections 24 of the core-forming element 12 is considerably facilitated, and more easily automated, because the two coil segments 30A, 30B are moved axially to engage with a projection 24 from opposite axial directions. Thus, all the coil segments 30A or 30B can be installed simultaneously onto all the projections 24 by a single axial movement. In contrast, the Conventional one-piece coils must first each be positioned in a central opening of the core-forming element 12 (i.e., defined between the inner ends 25a of the core protrusions 24), and then moved radially outward to install the coil onto a core protrusion. Since each protrusion of the core-forming element is located at a different angular position around a midline, each one-piece coil must be moved radially in an angular direction that differs from the radial direction of all other coils installed on the same core-forming element, thus complicating the automation of the coil installation process. After describing the basic structure and functions above, these and other elements of the stator assembly 10 of the present invention are described in more detail below.

[0027] Referring now to Figures 6, 7, 9 to 12, 14 and 15, the first shell half 32 of each of the plurality of coils 14 has an internal radial end 32a, an external radial end 32b, an external surface 36A, an internal surface 36B defining an elongated channel 37 extending radially between the internal and external ends 32a, 32b. As a result, each first shell half 32 is installed on a distinct protrusion among the protrusions 24 of the core-forming element by relative axial displacement between the first shell half 32 and said protrusion 24 in a first axial direction A1 ([Fig. 2]) such that at least a part of said protrusion 24 is arranged inside the elongated channel 37 of the first shell half 32.Similarly, each second shell half 34 has an internal radial end 34a, an external radial end 34b, an external surface 38A and an internal surface 38B, delimiting an elongated channel 39 extending radially between the internal and external ends 34a, 34b. With this structure, each second shell half 34 is installed on a distinct protrusion among the protrusions 24 of the core-forming element by relative axial displacement between the second shell half 34 and said protrusion 24 in a second opposite axial direction A2 ([Fig.2]). Thus, at least part of said projection 24 is disposed inside the elongated channel 39 of the second hull half 34. Therefore, when the hull halves 32, 34 are joined together, each projection 24 is enclosed or embedded inside the channels 37, 39 opposite the two hull halves 32, 34.

[0028] With reference to Figures 6 to 10, each first half of the shell 32 preferably comprises a first lateral wall 40 and a second lateral wall 42 extending radially between the internal and external radial ends 32a, 32b and parallel to each other. The two lateral walls 40, 42 define the elongated channel 37 and are connected by a central base wall 44 having opposite circumferential ends 44a, 44b. Specifically, the first lateral wall 40 extends axially from the first circumferential end 44a of the base wall 44 and the second Side wall 42 extends axially from the second circumferential end 44b of the base wall 44. Each side wall 40, 42 has a first edge 40a, 42a, respectively, forming an integral part of a circumferential end 44a, 44b, respectively, of the end wall 44 and a second free edge 40b, 42b designed to engage with the second half of the shell 34 as described below.

[0029] In order to fit together perfectly around a projection 24 of the core element, the two side walls 40, 42 preferably converge towards each other in a direction from the outer radial end 32b to the inner radial end 32a, so that each half of the shell 32 generally has a wedge shape. Furthermore, the base wall 44 is preferably flat and is positioned against the first axial end 24a of a projection 24 of the core element, so that the first half of the shell 32 generally has rectangular axial cross-sections. However, particularly if the projections 24 of the core element are curved, the base wall 44 can be curved in the same way, so that the first half of the shell 32 generally has U-shaped axial cross-sections (structure not shown).Furthermore, when installed around a projection 24, the first side wall 40 is disposed against the first circumferential end 24c of the enclosed projection 24 and the second side wall 42 is disposed against the second circumferential end 24d of the enclosed projection 24.

[0030] As best illustrated in [Fig.8], each first half of the shell 32 further preferably comprises a plurality of grooves 46 formed in the external surface 36A of the shell and spaced radially between the internal and external radial ends 32a, 32b. Each groove 46 is designed to receive a portion of at least one wire 17 of the winding 16 arranged around the coil 14 formed by the specific half of the shell 32. As a result, the grooves 46 retain the wire 17 during the winding process of the wire 17 around the coil 14 while also maintaining the separation between the adjacent windings of the winding 16. Most preferably, the grooves 46 comprise a first set of grooves 48A formed along a first corner 47a between the base wall 44 and the first side wall 40 and a second set of grooves 48B formed along a second corner 47b between the base wall 44 and the second side wall 42.The two sets of grooves 48A, 48B are preferably offset in the radial direction to facilitate the winding of the wire 17 around the spool 14 formed by the first half of the shell 32. Furthermore, each first half of the shell 32 also preferably includes a retaining flange 49 extending axially and circumferentially from the internal radial end 32a, each part of the flange 49 being designed to retain an internal radial end 16a of the winding 16 arranged around said spool 14 formed by the first. specific half of shell 32. Specifically, each retaining flange 49 has a radial section 49a extending radially outwards from the base wall 44 and two circumferential sections 49b extending outwards from the two side walls 40, 42.

[0031] Referring now to Figures 11 to 15, each second half of the shell 34 is generally constructed in a similar and complementary manner to each first half of the shell 32. Specifically, each second half of the shell 32 preferably comprises a first lateral wall 50 and a second lateral wall 52 extending radially between the internal and external radial ends 34a, 34b and parallel to each other. The two lateral walls 50, 52 define the elongated channel 39 and are connected by a central base wall 54 having opposite circumferential ends 54a, 54b. Specifically, the first lateral wall 50 extends axially from the first circumferential end 54a of the base wall 54 and the second lateral wall 52 extends axially from the second circumferential end 54b of the base wall 54.Each side wall 50, 52 has a first edge 50a, 52a, respectively, forming an integral part of a circumferential end 54a, 54b, respectively, of the base wall 54 and a second free edge 50b, 52b designed to engage with the second half of the hull 34 as described below.

[0032] In order to fit together perfectly around a protrusion 24 of the core-forming element, the two lateral walls 50, 52 preferably converge towards each other in a direction from the outer radial end 34b to the inner radial end 34a, so that each half of the shell 34 generally has a wedge shape. Furthermore, the base wall 54 is preferably flat and is positioned against the second axial end 54a of a protrusion 24 of the core-forming element, so that the second half of the shell 32 generally has rectangular axial cross-sections, but the base wall 53 can alternatively be curved so that the second half of the shell 34 generally has U-shaped cross-sections, as mentioned above with the first halves of the shell 32.Furthermore, when installed around a projection 24, the first side wall 50 is disposed against the second circumferential end 24c of the enclosed projection 24 and the second side wall 52 is disposed against the second circumferential end 24d of the enclosed projection 24.

[0033] As best illustrated in [Fig. 13], each second shell half 34 further preferably comprises a plurality of grooves 56 formed in the outer shell surface 38A and spaced radially between the inner and outer radial ends 34a, 34b. Each groove 56 is designed to receive a portion of at least one wire 17 of the winding 16 arranged around the coil 14 formed by the specific shell half 32 for the same reasons as those mentioned above. above with grooves 46. As with the first shell halves 32, the grooves 56 of the second shell halves 34 preferably comprise a first set of grooves 58A formed along a first corner 57a between the base wall 54 and the first side wall 50 and a second set of grooves 58B formed along a second corner 57b between the base wall 54 and the second side wall 52, which are preferably offset in the radial direction. In addition, each second shell half 34 preferably further comprises a retaining flange 59 extending axially and circumferentially from the inner radial end 34a of the shell half and designed to retain the inner radial end 16a of the associated winding 16.Specifically, each retaining flange 59 has a radial section 59a extending radially outwards from the base wall 54 and two circumferential sections 59b extending outwards from the two side walls 50, 52.

[0034] With reference to Figures 6, 7, 10, 12, and 15, with the structures described above, the first side walls 40, 50 of each of the first and second shell halves 32, 34 are each designed to engage by snap-fitting, and the second side walls 42, 52 of each of the first and second shell halves 32, 34 are also each designed to engage by snap-fitting. Preferably, the retaining flanges 49, 59 of the respective first and second shell halves 32, 34 are also designed to engage by snap-fitting.More specifically, each side wall 40, 42 of each first half of hull 32 has an elongated stepped section 40c, 42c extending inwards from the external surface 36B of hull adjacent to each external edge 40b, 42b of wall and each side wall 50, 52 of each second half of hull 34 has an elongated stepped section 50c, 52c adjacent to the external edges 50b, 52b of wall extending inwards from the internal surface 38B of hull. The two stepped sections 40c, 42c of the side walls 40, 42 of each first half of the hull 32 are in frictional contact with the respective stepped sections 50c, 52c of the side walls 50, 52 of each second half of the hull 34 to couple the two hull halves 32, 34 and thus enclose one of the protrusions 24 of the core-forming element.

[0035] Furthermore, the two circumferential sections 49b of the retaining flange 49 of each first half of the shell 32 each have a stepped section 49d extending inward from an internal radial surface 49c, and the two circumferential sections 59b of the retaining flange 59 of each second half of the shell 34 each have a stepped section 59d extending inward from an external radial surface 59c. The two stepped flange sections 49d of each first half of the shell 32 are engaged by friction with the stepped flange sections 59d of the associated second half of the shell 34 to further enhance the engagement. by snapping the first and second shell halves 32, 34 together. However, the shell halves 32, 34 of each coil 14 may be provided with any other structure to provide snap-fitting or may be held together by fasteners, adhesives or any other known means, as desired.

[0036] Referring now to Figures 1, 6, 7, 9 to 12, 14 and 15, as mentioned above, each coil 14 is preferably provided in the form of a pair 15 of coils 14 which are used to form a pair of north and south poles N, S. Specifically, the first shell half 32 of each of the pairs 15 of coils 14 is provided in the form of a pair 33 of first shell halves 32 connected by a first radially external skirt portion 60. Similarly, the second shell half 34 of each pair 15 of coils is provided in the form of a pair 35 of second shell halves 34 connected by a second radially external skirt portion 70. As with the hull halves 32, 34, the skirt parts 60, 70 have the function of electrically insulating the wires 17 of the windings 16 and the conductive lines (none shown) as well as providing mechanical rigidity to each coil 14.

[0037] With reference to Figures 6, 7, 9 and 10, the first skirt portion 60 of each pair 33 of the first shell halves 32 has a circumferential section 62 disposed against an internal circumferential surface section 23A of the annular portion 22 of the core element and a radial flange section 64 disposed against the first axial end 22a of the annular portion 22 of the core element. Each circumferential section 62 has a first circumferential end 62a formed in one piece with the radial outer end of the first lateral wall 40 of a first "left" shell half of the first shell halves 32 and a second circumferential end 62a formed in one piece with the radial outer end of the second lateral wall 42 of a first "right" shell half of the first shell halves 32.Preferably, the first skirt part 60 further comprises a first circumferential end section 65A extending circumferentially from the second side wall 42 of the "left" hull half 32 and a second circumferential end section 65B extending circumferentially from the first side wall 40 of the "right" hull half 32.

[0038] Furthermore, each radial flange section 64 is formed as a single unit with the two base walls 44 of the connected shell halves 32 and with the circumferential section 62 of the first skirt portion 60. Preferably, each radial flange section 64 extends circumferentially outwards beyond the outer walls 40, 42 of the connected shell halves 32 in order to provide a large mounting surface 63B for the conductive lines and conductor wires 17. Specifically, the section flange 64 has first and second circumferential ends 64a, 64b, an internal axial surface 63A disposed against the first axial end 22a of the annular part 22 of the core-forming element and an opposing external axial surface 63B.

[0039] As illustrated in Figures 6 and 9, the radial flange section 64 of each first skirt portion 60 preferably comprises two elongated central shoulders 66A, 66B and two end shoulders 67A, 67B, each shoulder 66A, 66B, 67A and 67B extending axially outwards and circumferentially from the flange section 64. Specifically, one elongated shoulder 66A is located adjacent to the outer radial end 32b of the "left" shell half among the first shell halves 32 and the other shoulder 66B is located adjacent to the outer radial end 32b of the "left" shell half among the first shell halves 32, each shoulder 66A, 66B having an external surface 69 around which a wire 17 can be partially rolled up.Shoulder 66B has a retaining notch 68 designed to receive and hold under tension a portion of at least one wire 17 extending radially outwards from the winding 16 arranged on the adjacent reel 14, as illustrated in [Fig. 5]. In addition, each end shoulder 67A and 67B is located adjacent to a circumferential end 64a, 64b separate, respectively, from the radial flange section 64. Each end shoulder 67A, 67B and the extended shoulder 66B have a clearance opening 69 and a tie bar 71 for attaching cable ties for a conductor wire or winding wire 17.

[0040] Now referring to figures 11, 12, 14 and 15, the second skirt part 70 of each pair 35 of the second shell halves 34 has a circumferential section 72 disposed against an internal circumferential surface section 23A of the annular part 22 of the core-forming element and a radial flange section 74 disposed against the second axial end 22a of the annular part 22 of the core-forming element. Each circumferential section 72 has a first circumferential end 72a formed in one piece with the radial outer end of the first lateral wall 50 of a second "left" shell half of the second shell halves 34 and a second circumferential end 72a formed in one piece with the radial outer end of the second lateral wall 52 of a first "right" shell half of the first shell halves 34.Preferably, the second skirt part 70 further comprises a first circumferential end section 75A extending circumferentially from the second side wall 52 of the "left" hull half 34 and a second circumferential end section 75B extending circumferentially from the first side wall 50 of the "right" hull half 34.

[0041] Furthermore, each radial flange section 74 of each second skirt part 70 is generally flat and has opposing first and second circumferential ends 74a, 74b, an internal axial surface 76A disposed against the second axial end 22b of the annular part 22 of the core-forming element, and an opposing external axial surface 76B. Preferably, the flange section 74 is dimensioned so as to have a radial dimension that is substantially smaller than a radial dimension of the radial flange section 64 of each first skirt part 60, but has a substantially greater axial thickness than the radial flange section 64. Consequently, the base wall 54 of each second shell half 34 is preferably axially spaced inwards from the external axial surface 76B of the flange section 74, as best illustrated in [Fig. 11].

[0042] Furthermore, the circumferential section 72 of each second skirt portion 70 has an axial edge 77 designed to connect to an axial edge 61 of the first skirt portion 60 of the specific pair 15 of coils 14. Preferably, the circumferential section 62 of each first skirt portion 60 has an elongated stepped section 62c extending inward from an internal wall surface adjacent to the axial edge 63, and the circumferential section 72 of each second skirt portion 70 has an elongated stepped section 72c extending inward from the internal shell surface adjacent to the axial edge 77. The stepped sections 62c, 72c of the two circumferential sections 62, 72 are frictionally engaged to couple the first and second skirt portions 60, 70, so that the radial flange sections 64, 74 are held arranged against the axial ends 22a, 22b of the annular part 22 of the core-forming element.

[0043] With reference to Figures 1, 6, 7, 11 and 12, at least one, and preferably both, of the first skirt part 60 and the second skirt part 70, of each pair 15 of coils 14 is designed to connect to a corresponding skirt part of the first skirt part 60 and the second skirt part 70 of each circumferentially adjacent pair 15 of coils 14. Specifically, each first skirt part 60 has an axial recess 80 formed in the first circumferential end section 65A and the end shoulder 67A and an axial projection 82 extending circumferentially outwards from the second circumferential end section 65B and the end shoulder 67B. Each projection 82 of the first skirt part 60 of a pair 15 of coils 14 is received in the recess 80 of the first skirt part 60 of an adjacent pair 15 of coils 14 to couple the two adjacent pairs 15 of coils 14.Similarly, each second skirt part 70 has an axial projection 84 formed in the first circumferential end section 75A and the first circumferential end 74a of the flange section 74 and an axial recess 86 extending. circumferentially outwards from the second circumferential end section 75B and the second circumferential end 74b of the flange section 74. Each projection 84 of the second skirt part 70 of a pair 15 of coils 14 is received in the recess 86 of the second skirt part 70 of an adjacent pair 15 of coils 14 to also couple the two adjacent pairs 15 of coils 14.

[0044] Although each shell half 32 or 34 is preferably supplied as a pair 33, 35 of the two shell halves 32, 34 which provide a pair 15 of coils 14, each coil 14 may alternatively be supplied as a single component comprising only a first shell half 32 and a second shell half 34. Furthermore, the two segments 30A, 30B of each coil 14 may take a form other than a shell half. For example, the first segment 30A may take the form of a main body element with a central cavity 31 and a lateral opening which allows the main body element to be installed axially on a projection 24 of the core-forming element, and the second segment 30B may take the form of a cover which can be connected to the main body element to close the lateral opening (structure not shown).The present invention encompasses all the structures of the two-segment coil 14 described and / or represented herein and any other suitable structure which allows each coil 14 to be axially assembled on the projections 24 of the core-forming element.

[0045] Representative, but not limiting, examples of the present invention have been described in detail above with reference to the accompanying drawings. This detailed description is intended merely to instruct a person skilled in the art in further details for the practice of preferred aspects of the present invention and is not intended to limit the scope of the invention.

[0046] Furthermore, the combinations of features and steps disclosed in the detailed description above may not be mandatory for carrying out the invention in the broadest sense and are rather provided simply to describe particular representative examples of the invention. In addition, various features of the representative examples described above, as well as the various independent and dependent claims below, may be combined in a manner not specifically and explicitly stated in order to provide additional useful embodiments of the present invention.

[0047] All features disclosed in the description and / or claims are intended to be disclosed separately and independently of each other for the purposes of the original written disclosure, as well as for the purpose of limiting the claimed subject matter, regardless of the compositions of the features in the embodiments and / or claims. Furthermore, all ranges of values ​​or indications The groups of entities are intended to disclose any possible intermediate value or intermediate entity for the purposes of the original written disclosure, as well as for the purposes of limiting the claimed subject matter. The invention is not limited to the embodiments described above and may vary within the scope of the following claims.

Claims

Claims

1. A stator assembly (10) for a magnetic bearing, the stator assembly (10) comprising: a core member (12) formed of a ferromagnetic material, having a centerline (Lc) and including an outer annular portion (22) and a plurality of projections (24) extending radially inward from the outer annular portion and circumferentially spaced about the centerline (Lc), each projection (24) having a first axial end (24a) and an opposing second axial end (24b);a plurality of coils (14), each coil (14) being formed of an electrically insulating material and comprising a first shell half (32) disposed against the first axial end (24a) of a distinct projection (24) among the plurality of projections and a second shell half (34) disposed against the second axial end (24b) of said projection (24) and coupled to the first shell half (32) such that said projection (24) is enclosed within a cavity (31) defined between the first (32) and second (34) shell halves; and a plurality of windings (16) each having at least one wire (17) wound around a separate one of the plurality of coils (14), each winding (16) being electrically couplable to a source of electrical power such that each winding (16) and the projection (24) encircled by the winding provide a pole of the stator.;

2. A stator assembly according to claim 1, the first half shell (32) of each coil (14) of the plurality of coils having an inner radial end (32a), an outer radial end (32b) and an elongated channel (37) extending radially between the inner (32a) and outer (32b) ends such that each first half shell (32) is installed on a distinct projection (24) among the projections of the core member by relative axial displacement between the first half shell (32) and said projection (34) in a first axial direction (A1) such that at least a portion of said projection (24) fits within the elongated channel (37) of the first half shell (32); and

3. the second shell half (34) of each coil (14) of the plurality of coils having an inner radial end (34a), an outer radial end (34b) and an elongated channel (39) extending radially between the inner (34a) and outer (34b) ends such that each second shell half (34) is installed on a distinct projection (24) among the projections of the core element by relative axial displacement between the second shell half (34) and said projection (24) in an opposite second axial direction (A2) such that at least a portion of said projection (24) fits within the elongated channel (39) of the second shell half (34).A stator assembly according to claim 1, each projection (24) of the projections of the core member (12) having a first circumferential end (24c) and an opposing second circumferential end (24d), the first and second circumferential ends extending axially between the first (24a) and second (24b) axial ends of the projection;. the first shell half (32) of each coil (14) of the plurality of coils having an inner radial end (32a), an outer radial end (32b), a first side wall (40) disposed against the first circumferential end (24c) of the enclosed projection (24) and a second side wall (42) disposed against the second circumferential end (24d) of the enclosed projection (24), the first (40) and second (42) side walls extending radially between the inner (32a) and outer (32b) radial ends; and the second shell half (34) of each coil (14) of the plurality of coils having an inner radial end (34a), an outer radial end (34b), a first side wall (50) disposed against the first circumferential end (24c) of the enclosed projection (24) and a second side wall (52) disposed against the second circumferential end (24d) of the enclosed projection (24), the first (50) and second (52) side walls extending radially between the inner (34a) and outer (34b) radial ends and each having a free end (50b, 52b), the first side wall (40) of the first shell half (32) being connected to the first side wall (50) of the second shell half (34) and the second side wall (42) of the first half shell (32) being connected to the second side wall (52) of the second shell half (34).

4. A stator assembly according to claim 3, an elongated channel (37) being defined between the first (40) and second (42) side walls of the first shell half (32) of each coil such that each first shell half (32) is seated on a distinct projection (24) among the projections of the core member (12) by relative axial displacement between the first shell half and said projection such that at least a portion of said projection fits within the elongated channel (37) of the first shell half (32);and an elongated channel (39) being defined between the first (50) and second (52) side walls of the second shell half (34) of each coil (14) such that each second shell half (34) is seated on a distinct projection (24) among the projections of the core member (12) by relative axial displacement between the second shell half and said projection such that at least a portion of said projection fits within the elongated channel (39) of the second shell half (34).;

5. The stator assembly of claim 4, wherein the first side wall (40) of each first shell half (32) and the first side wall (50) of each second shell half (34) are each adapted to snap-in engagement and the second side wall (42) of each first shell half (32) and the second side wall (52) of each second shell half (34) are each adapted to snap-in engagement.

6. A stator assembly according to claim 1, the first shell half (32) of each coil (14) of the plurality of coils being provided as a pair (33) of first shell halves connected by a first skirt portion (60), the first skirt portion (60) having a circumferential section (62) capable of being disposed against an inner circumferential surface section (23A) of the annular portion (22) of the core member (12) extending between two adjacent projections of the core member and a radial flange section (64) capable of being disposed against a first axial end (22a) of the annular portion (22) of the core member (12); and

7.

8. the second shell half (34) of each of the plurality of coils being provided as a pair (35) of second shell halves connected by a second skirt portion (70), the second skirt portion (70) having a circumferential section (72) capable of being disposed against an inner circumferential surface section (23A) of the annular portion (22) of the core member (12) extending between two adjacent projections of the core member and capable of being connected to the circumferential section (62) of the first skirt portion (60) and a radial flange section (74) capable of being disposed against a second axial end (22a) of the annular portion (22) of the core member, each shell half (34) of the pair (35) of second shell halves being connected to a shell half (32) distinct from the shell halves of the pair (33) of first halves of hull so as to form two coils. A stator assembly according to claim 6, the radial flange section (64) of the first skirt portion (60) having two elongated shoulders (66A, 66B, 67A, 67B) each extending axially outwardly and circumferentially, one shoulder being located adjacent one of the first shell halves (32) and the other shoulder being located adjacent a radially outer end of the other of the first shell halves, each shoulder (66A, 66B) having a retaining notch (68) adapted to hold in tension a portion of the at least one wire extending radially outwardly from the winding disposed on the adjacent bobbin and / or a clearance opening (69) for securing cable ties for a lead wire or a winding wire. A stator assembly according to claim 6, each projection (24) of the core member projections having a first circumferential end (24c) and an opposing second circumferential end (24d), the first (24c) and second (24d) circumferential ends extending axially between the first (24a) and second (24b) axial ends of the projection; each first shell half (32) of each pair (33) of the pairs of first shell halves having an inner radial end (32a), an outer radial end (32b), a first wall

9. side wall (40) disposed against the first circumferential end (24c) of the enclosed projection (24) and a second side wall (42) disposed against the second circumferential end (24d) of the enclosed projection, the first (40) and second (42) side walls extending radially between the inner (32a) and outer (32b) radial ends, the first side wall of one of the pair of first shell halves being integrally connected to the second side wall of the other of the pair of first side walls by the circumferential section (62) of the first skirt portion (60); and each second shell half (34) of each pair (35) of the pairs of second shell halves having an inner radial end (34a), an outer radial end (34b), a first side wall (50) disposed against the first circumferential end (24c) of the enclosed projection and a second side wall (52) disposed against the second circumferential end (24d) of the enclosed projection, the first (50) and second (52) side walls extending radially between the inner (34a) and outer (34b) radial ends, the first side wall of one of the pair of second shell halves being integrally connected to the second side wall of the other of the pair of second shell halves by the circumferential section (72) of the second skirt portion (70),the first side wall (40) of each of the first shell halves (32) being connected to the first side wall (50) of the second shell half (34) coupled to said first shell half (32) and the second side wall (42) of each of the first shell halves (32) being connected to the second side wall (52) of the second shell half (34) coupled to said first shell half (32)., The stator assembly of claim 1, each of the first shell half (32) and the second shell half (34) of each coil of the plurality of coils having an inner radial end (32a, 34a), an outer radial end (32b, 34b), an outer surface (36A, 38A) and a plurality of grooves (46, 56) formed in the outer surface and radially spaced between the inner and outer radial ends, each groove being adapted to receive a portion of the at least one wire of the winding disposed around said coil.

10. The stator assembly of claim 9, each of the first shell half and the second shell half of each of the plurality of coils including a central base wall (44, 54) having first (44a, 54a) and second (44b, 54b) circumferential ends, a first side wall (40, 50) extending axially from the first circumferential end (44a, 54a) of the central end wall, and a second side wall (42, 52) extending axially from the second circumferential end (44b, 54b) of the central end wall (44, 54);and the plurality of grooves (46, 56) of each coil (14) of the plurality of coils comprising a first set of grooves (48A, 58A) formed along an edge (50a, 52a) between the central end wall (44, 54) and the first side wall (40, 50) and a second set of grooves (48B, 58B) formed along an edge between the central end wall (44, 54) and the second side wall (42, 52).;

11. A stator assembly according to claim 1, each of the first shell half (32) and the second shell half (34) of each coil (14) of the plurality of coils having an inner radial end (32a, 34a) and a retaining flange (59) extending axially and circumferentially from the inner radial end (32a, 34a), each flange portion being adapted to retain an inner radial end of the winding (16) disposed around said coil (14).

12. The stator assembly of claim 1, wherein the first shell half (32) of each of the plurality of coils has a radially outer end (32b) and each coil further comprises a first skirt portion (60) extending radially outward from the radially outer end of the first shell half and disposed against a first axial end (22a) of the annular portion (22) of the core member (12); and the second shell half (34) of each of the plurality of coils has a radially outer end (34b) and each coil further comprises a second skirt portion (70) extending radially outward from the radially outer end of the second shell half and disposed against a second

13. axial end (22b) of the annular part (22) of the core-forming element (12). A stator assembly (10) for a magnetic bearing, the stator assembly comprising: a core member (12) formed of a ferromagnetic material, having a centerline (Lc) and including an outer annular portion (22) and a plurality of projections (24) extending radially inwardly from the outer annular portion (22) and circumferentially spaced about the centerline (Lc), each projection (24) having a first axial end (24a) and an opposing second axial end (24b); a plurality of coils (14) formed of an electrically insulating material, each coil (14) being provided as a pair (33, 35) of coils comprising a pair (33) of first shell halves (32) connected by a first skirt portion (60), each of the first shell halves (32) being disposed against the first axial end (24a) of a distinct projection (24) of two of the plurality of projections, and a pair (35) of second shell halves (34) connected by a second skirt portion (70), each of the second shell halves being disposed against the second axial end (24b) of a distinct projection (24) of the two projections, one of the second shell halves (33,34) being coupled to one of the two first shell halves disposed against the same projection of the two projections to enclose the projection within a cavity (31) defined between the first (32) and second (34) shell halves and the other of the second shell halves (32, 34) being coupled to the first shell half of the two first shell halves disposed against the same projection of the two projections to enclose the projection within a cavity (31) defined between the first (32) and second (34) shell halves; and, a plurality of windings (16) each comprising at least one wire (17) wound around a coil (14) distinct from the plurality of coils, each winding being electrically coupleable to a source of electrical power, the winding being arranged around a coil of each pair of coils and the projection encircled by the winding providing a north pole of the stator and the winding

14. disposed around the other coil of each pair of coils and the projection encircled by the winding providing a south pole of the stator. A stator assembly according to claim 13, each projection (24) of the projections of the core member (12) having a first circumferential end (24c) and an opposite second circumferential end (24d), the first (24c) and second (24d) circumferential ends extending axially between the first (24a) and second (24b) axial ends of the projection (24); each first shell half (32) of each pair (33) of the pairs of first shell halves having an inner radial end (32a), an outer radial end (32b), a first side wall (40) disposed against the first circumferential end (24c) of the enclosed projection (24) and a second side wall (42) disposed against the second circumferential end (24d) of the enclosed projection (24), the first (40) and second (42) side walls extending radially between the inner (32a) and outer (32b) radial ends, the first side wall (40) of one of the pair of first shell halves being integrally connected to the second (42) side wall of the other of the pair of first side walls by the circumferential section (62) of the first skirt portion (60); each second shell half (34) of each pair (35) of the pairs of second shell halves having an inner radial end (34a), an outer radial end (34b), a first side wall (50) disposed against the first circumferential end (24c) of the enclosed projection and a second side wall (52) disposed against the second circumferential end (24d) of the enclosed projection, the first (50) and second (52) side walls extending radially between the inner (34a) and outer (34b) radial ends, the first side wall (50) of one of the pair (35) of second shell halves being integrally connected to the second side wall (52) of the other of the pair of second shell halves by a circumferential section (72) of the second skirt portion (70),each first side wall (50) of each second shell half (34) being connected to the first side wall (40) of the first shell half (32) and each second side wall (52) of each second shell half, (34) being connected to the second side wall (42) of each first half shell (32).

15. A stator assembly according to claim 14, an elongated channel (37) being defined between the first (40) and second (42) side walls of each first shell half (32) of each pair of first shell halves such that each pair (33) of first shell halves is installed on a separate pair of the protrusions of the core member by relative axial displacement between the pair (33) of first shell halves and the pair of protrusions in a first axial direction (A1) such that at least a portion of said protrusion of the pair of protrusions fits within the elongated channel (37) of a separate first shell half (32) of the pair (33) of first shell halves;and an elongated channel (39) being defined between the first (50) and second (52) side walls of each second shell half (34) of each pair of second shell halves such that each pair (35) of second shell halves is seated on a distinct pair of the projections of the core member by relative axial displacement between the pair (35) of second shell halves and the pair of projections in an opposite second axial direction (A2) such that at least a portion of a projection of the pair of projections fits within the elongated channel (39) of a distinct second shell half (34) of the pair (35) of second shell halves.;

16. The stator assembly of claim 14, wherein the first side wall (40) of each first shell half (32) of the pair (33) of first shell halves and the first side wall (50) of each second shell half (34) of the pair (35) of second shell halves are each adapted to engage in a snap-fit ​​manner and the second side wall (42) of each first shell half (32) of the pair (33) of first shell halves and the second side wall (52) of each second shell half (34) of the pair (35) of second shell halves are each adapted to engage in a snap-fit ​​manner.

17. A stator assembly according to claim 13, each first skirt portion (60) having a circumferential section (62) capable of being disposed against an inner circumferential surface section (23A) of the annular portion (22) of the core member (22) extending between two projections

18.

19. adjacent projections of the core member and a radial flange section (64) disposeable against a first axial end (22a) of the annular portion (22) of the core member (12); and each second skirt portion (70) having a circumferential section (72) disposeable against the inner circumferential surface section (23A) of the annular portion (22) of the core member (12) extending between the two adjacent projections of the core member and connected to the circumferential section (62) of the first skirt portion (60) and a radial flange section (74) disposeable against a second axial end (22b) of the annular portion (22) of the core member (12). The stator assembly of claim 13, at least one of the first skirt portion (60) and the second skirt portion (70) of each pair of coils being adapted to connect to a corresponding one of the first skirt portion and the second skirt portion of each circumferentially adjacent pair of coils. A stator assembly (10) for a magnetic bearing, the stator assembly comprising: a core member (12) formed of a ferromagnetic material, having a center line (Lc) and including an outer annular portion (22) and a plurality of projections (24) extending radially inward from the outer annular portion (22) and circumferentially spaced about the center line (Lc); a plurality of coils, each coil (14) being formed of an electrically insulating material and comprising a first segment (30A) having a first open cavity (31) disposed against a distinct projection (24) among the plurality of projections such that a portion of said projection (24) is disposed within the first open cavity (31) and a second segment (30B) having a second open cavity (31) disposed against said projection such that a remaining portion of said projection (24) is disposed within the second open cavity, the second segment (30B) being coupled to the first segment (30A) such that said projection (24) is enclosed within the first and second coil segments; and

20. a plurality of windings (16) each having at least one wire (17) wound around a separate one of the plurality of coils, each winding (16) being electrically coupleable to an electrical power source such that each winding (16) and the projection (24) encircled by the winding provide a pole of the stator. A stator assembly according to claim 19, the first segment (30A) of each coil (14) of the plurality of coils being provided as a pair (33) of first segments connected by a first skirt portion (60), the first skirt portion (60) having a circumferential section (62) capable of being disposed against an inner circumferential surface section (23A) of the annular portion (22) of the core member (12) extending between two adjacent projections of the core member and a radial flange section (64) capable of being disposed against a first axial end (22a) of the annular portion (22) of the core member (12); and the second segment (30B) of each coil (14) of the plurality of coils being provided as a pair (35) of second segments connected by a second skirt portion (70), the second skirt portion (70) having a circumferential section (72) capable of being disposed against an inner circumferential surface section (23A) of the annular portion (22) of the core member (12) extending between two adjacent projections of the core member and capable of being connected to the circumferential section (62) of the first skirt portion (60) and a radial flange section (74) capable of being disposed against a second axial end (22b) of the annular portion (22) of the core member (12), each segment of the pair of second segments being connected to a separate segment of the pair of first segments so as to form two coils.

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