WO2006074456A2

WO2006074456A2 - Apparatus and method for mounting windings on a stator core

Info

Publication number: WO2006074456A2
Application number: PCT/US2006/000850
Authority: WO
Inventors: Andrew Anspach
Original assignee: Advanced Machine And Tool Corporation
Priority date: 2005-01-04
Filing date: 2006-01-03
Publication date: 2006-07-13
Also published as: WO2006074456A3

Abstract

An apparatus for installing a wire pack on a stator core. A wire pack is placed on a wire drum of the apparatus. The wire drum is rotated in cooperation with a series of transfer members. The wire pack is transferred to the transfer members on an individual slot segment basis. The slot members rotate about a central axis of the stator core and pick the wire pack from the wire drum at an axially spaced distance from the stator core. The transfer members form the wire pack into a partially spiral shape as the wire pack is rotated and axially translated by the transfer members. The transfer members position the wire pack within the central opening of the stator core. The wire pack is removed from the transfer members and inserted into the slots of the stator core on an individual slot basis. Alternatively, the wire pack may be installed into a small number of slots simultaneously.

Description

APPARATUS AND METHOD FOR MOUNTING WINDINGS ON A STATOR CORE

BACKGROUND OF THE INVENTION

1. Field of the Invention.

[0001] The present invention relates to the manufacture of stator cores, and more specifically, to an apparatus and method of mounting windings on a stator core which is suitable for use in the alternator of an automobile.

2. Description of the Related Art.

[0002] The use of electrical alternators in automobiles is well known. The stator of such alternators typically includes a core with a number of circumferentially spaced and axially extending slots. The stator also includes windings which are positioned in the slots of the stator core. Conventionally, the windings of such alternators utilize wires having a generally round cross section. Recently, however, windings have been developed that utilize wires having rectilinear or oval cross sections that allow the slots of the stator to be more densely packed with wire providing a higher slot fill ratio. A higher slot fill ratio provides several advantages and may allow the diameter of the stator to be reduced. Examples of such alternator stators are disclosed in U.S. Patent Nos. 6,826,823 B2 (Neet); 6,787,961 B2 (Neet et al); 6,759,779 B2 (Neet); 6,750,582 Bl (Neet); 6,750,581 B2 (Neet) and in U.S. Patent Pub. Nos-. 2004/0070305 Al (Neet); 2004/0119359 Al (Neet); 2004/0119360 Al (Neet); 2004/0119361 Al (Neet et al.); 2004/0119362 Al (Neet); 2004/0135458 Al (Neet); 2004/0183389 Al (Neet); 2004/0207284 Al (Neet); 2004/0212268 Al (Neet); and 2004/0237287 Al (Bramson et al.), and the disclosures of each of these patents and publications being all expressly incorporated herein by reference. [0003] When manufacturing a conventional alternator stator, the windings are typically assembled into a wire pack and formed into a generally cylindrical shape. The entire wire pack is then positioned within the stator while in a generally cylindrical configuration and the wires of the wire pack are then substantially simultaneously forced radially outwardly into their respective slots. This method of assembly is not well suited for compact alternator stators which utilize windings formed of wires with non-circular cross sections and having a high slot fill ratio.

SUMMARY OF THE INVENTION

[0004] The present invention provides an improved method and apparatus for installing the windings on a stator core of an electrical machine. The disclosed method and apparatus are well- suited for installing windings formed with wire having a rectangular or oval cross section on an alternator stator core.

[0005] The invention comprises, in one form thereof, a method for installing a wire pack on a stator core. After or with forming the wire pack, the wire pack is placed on the wire holding drum of the apparatus. The wire holding drum is rotated in cooperation with a series of transfer members. The wire pack is transferred to the transfer members on an individual slot segment basis. The slot members rotate about a central axis of the stator core and pick the wire pack from the wire drum at an axially spaced distance from the stator core. The transfer members are translated in an axial direction as they rotate and the wire pack assumes a partially spiral shape as the wire pack is moved by the transfer members. The transfer members position the wire pack within the central opening of the stator core. The wire pack is then removed from the transfer members and inserted into the slots of the stator core on an individual slot basis. Alternatively, the wire pack may installed into a small number of slots (less than the total number of slots) simultaneously.

[0006] An advantage of the present invention is that it provides an apparatus that can be used to install a wire pack formed of wire with a non-circular cross section, e.g., a rectangular cross section, on a stator core.

[0007] Another advantage is that it is adaptable for use with relatively small diameter stator cores.

BRIEF DESCRIPTION QF THE DRAWINGS

[0008] The above mentioned and other features of this invention, and the manner of attaining them, will become more apparent and the invention itself will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

Figure 1 is a perspective view of a stator core.

Figure 2 is a top view of a wire pack.

Figure 3 is a partial cross sectional view of a stator core with windings mounted therein.

Figure 4 is a partial cross sectional view of a stator core and the end turn segment of a winding.

Figure 5 is a cross sectional view of an apparatus for installing a wire pack on a stator core. Figure 6 is a cross sectional view of the wire drum and transfer members of the apparatus of Figure 5.

Figure 7 is a schematic cross sectional view illustrating the transfer of the wire pack from the wire drum to the transfer members.

Figure 8 is a schematic cross sectional view illustrating the movement of the wire pack by the transfer members.

Figure 9 is a schematic cross sectional view illustrating the transfer of the wire pack from the transfer members to the stator core.

Figure 10 is a view of the camming groove located on the interior of the barrel cam. [0009] Corresponding reference characters indicate corresponding parts throughout the several views. Although the exemplification set out herein illustrates an embodiment of the invention, in one form, the embodiment disclosed below is not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise form disclosed.

DETAILED DESCRIPTION OF THE INVENTION

[0010] The embodiment of the present invention illustrated in the figures and described below is adapted to install windings formed with wire having a rectilinear, rectangular, or oval cross section on a stator core for an automobile alternator. The present invention, however, may be used in the manufacture of a variety of different electric machines for the mounting of windings, formed with wiring having either circular and non-circular cross sections, on a stator or a rotor core.

[0011] Figure 1 illustrates a stator core 20 that can be used with the present invention. Stator core 20 includes a series of circumferentially spaced and axially extending slots 22 separated by teeth 24. An outer portion 26 of core 20 connects the individual radially extending teeth 24. Stator core 20 defines axis 28 and may be formed out of a plurality of stacked sheet metal laminations as is well known in the art.

[0012] Figure 2 illustrates a wire pack 30 that is used to form the windings of an alternator stator. Wire pack 30 is formed by positioning a plurality of separate, continuous wires 32 in interwoven predetermined positions. In the illustrated embodiment, wires 32, 32a have a substantially rectilinear cross section so that wires 32, 32a may more fully fill slots 22. In Figure 2, individual wire 32a is highlighted to illustrate the path of a single exemplary wire. The individual wires 32, 32a are configured to define linear slot segments 34 and end turn segments 36. As best seen in Figures 3 and 4, slot segments 34 are positioned in slots 22 of stator 20 while end turn segments 36 extend beyond the axial ends of slots 22 and teeth 24. The determination of a precise winding pattern of wires 32 to form a wire pack 30 for a particular alternator design is well known by those having ordinary skill in the art. For example, a single phase alternator will typically require two conductors or wires 32 while a three phase alternator will require six wires 32. The winding pattern will also determine the relative location of each wire 32 in slots 22 around the circumference of stator 20. For example, wire 32a may be positioned at a radially inner location in one slot 22 while being positioned at a radially outer position in another slot 22. The relative position of slot segments 34 in wire pack 30 conforms to the desired location of wires 32 in slots 22. The formation of a wire pack 30 in a flat condition as schematically depicted in Figure 2 is also known to those having ordinary skill in the art. For example, U.S. Pub. No. 2004/02372787 discloses a method for forming such a flat wire pack utilizing wires having non-circular cross sections that can be used with the present invention. [0013] Apparatus 40 (Figure 5) is used to install wire pack 30 on stator core 20. Apparatus 40 includes a wire drum 42 having a plurality of teeth 44 and grooves 45 encircling the outer circumferential perimeter of drum 42. After wire pack 30 has been formed, the flat wire pack 30 is wrapped around the exterior of wire drum 42 with slot segments 34 being positioned in grooves 45. Teeth 44 have an axially extending height that is no greater than the length of slot segments 34 whereby slot segments 34 can be positioned in grooves 45 with end turn segments 36 being positioned above and below teeth 44.

[0014] Wire drum 42 rotates in cooperation with transfer members 46 whereby wire pack 30 is transferred from drum 42 to transfer members 46 as schematically depicted in Figure 7. Vertically extending transfer members 46 each include two wire slots 48 with a central tab 50 disposed therebetween as can be seen in Figure 8. Wire slots 48 are spaced apart by a distance that allows slots 48 to receive the upper and lower end turn segments 36 of wire pack 30. The rotation of wire drum 42 and transfer members 46 positions a transfer member 46 between each adjacent pair of slot segments 34 on drum 42 as seen in Figure 7. As tab 50 is positioned between adjacent slot segments 34, end turn segments 36 are positioned in wire slots 48 on transfer members 46. A stationary wedge 52 is positioned adjacent the outer perimeter of drum 42 immediately above and below teeth 44 whereby wedges 52 can engage the end turn segments 36 of wire pack 30 without interfering with teeth 44 to ensure the transfer of wires 32 from drum 42 to transfer members 46. Cam-actuated push arms or other suitable methods could also be employed to ensure that wire pack 30 is transferred from drum 42 to transfer members 46. Wire pack 30 is depicted as a single wire 32 in Figure 7 for purposes of graphical clarity but would typically include a plurality of wires 32.

[0015] After wires 32 have been positioned on transfer members 46, transfer members continue to rotate and also axially translate wires 32 to a position within stator core 20 where wires 32 are transferred to stator core 20. During the rotational and axial translation of wire pack 30 between drum 42 and the interior of stator core 20, a stationary shield member 53 positioned adjacent the moving transfer members 46 (Figures 7 and 8) maintains end turn segments 36 within slots 48 and ensures that wire pack 30 does not become disengaged from transfer members 46. Shield member 53 is formed of a sheet metal material and is partially cylindrical in shape and is positioned adjacent the outer radial surface of transfer members 46 for the circumferential distance wherein wire pack 30 is being transferred from wire drum 42 to the interior opening of stator core 20. The rotational and axial translation of transfer members 46 after receiving wire pack 30 from drum 42 stretches wire pack 30 into a partially helical spiral between wire drum 42 and stator core 20 as it is transferred from drum 42 to the interior of stator core 20 as depicted by dashed outline 56 in Figure 5.

[0016] Once a portion of the wire pack 30 has been positioned within the open center of stator core 20 and properly aligned with slots 22, injectors 54a-d are used to push wire pack 30 from transfer members 46 and onto stator core 20 as schematically depicted in Figure 9. Wire pack 30 is installed on stator core 20 by inserting wires 32 into slots 22 either one at a time or by inserting wires 32 into a small number, e.g., four slots 22, at a single time. Injectors are located between each of the transfer members 46 where they are positioned to engage the slot segments 34 of wire pack 30. The injectors, e.g., injectors 54a-d, are moved radially outwardly when the slot segments 34 are properly positioned relative to a slot 22 in stator core 20 to thereby push slot segments 34 into slot 22. After wire pack 30 has been removed from a transfer member 46, it continues to rotate and is axially translated toward drum 42 where it returns to pick up another portion of wire pack 30.

[0017] Injectors 54a-d may be pneumatically or cam actuated. Figure 9 schematically depicts the injection of wires 32 onto stator core 20. In Figure 9, wire 32 is positioned at the proper vertical height relative to stator core 20 within the rotational range 60c-60d with the slots labelled 22a-22d falling within this range. Stator core 20 is rotated together with transfer members 46 whereby each transfer member 46 remains circumferentially aligned with a tooth 24 as both stator core 20 and transfer members 46 are rotated. As discussed in greater detail below, the transfer members 46 also move axially (with respect to machine axis 76) as they rotate to pick wires 32 from wire drum 42 and lift the wires into the interior space of stator core 20 where they may be injected into slots 22 by injectors. Within the range 60c-60d, wires 32 are at the proper vertical position for injection into stator core 20.

[0018] Injectors 54a-d provide a schematic illustration of how an injector pushes wires 32 from transfer members 46 into slots 22 when wires 32 are properly aligned with slots 22. At slot 22a, wire 32 has just moved into proper vertical alignment with slot 22a and injector 54a begins moving radially outwardly, at slot 22b, injector 54b has progressed further radially outwardly and pushed wire 32 into slot 22b. At slot 22c, injector 54c has progressed even further radially outwardly and pushed wire 32 to its final position within slot 22c. At slot 22d, injector 54d has been retracted to allow adjacent transfer members 46 to pick up additional wiring in slots 48. Each set of injectors 54, transfer members 46, and slots 22 has wiring injected into slots 22 in this same manner as the injectors 54, transfer members 46 and slots 22 rotate through the injection range segment 60c-60d during each revolution of the stator core 22 and transfer members 46.

[0019] Apparatus 40 includes a barrel cam member 58 to control the axial movement of transfer members 46. (The axial movement of members 46 is a vertical movement in the illustrated embodiment, however other orientations of machine axis 76 could also be employed.) Barrel cam member 58 is stationary and has a cylindrical shape. A camming groove 60 is located on the radially inward surface 59 of barrel cam member 58. As best seen in Figure 5, each of the vertically extending transfer members 46 is attached to a lateral member 62. The lateral members 62 are each attached to a roller 64 located in camming groove 60 by a threaded shaft 66. Vertically oriented driving members 68 extend upwardly from bottom plate 70. A separate driving member 68 is provided for the lateral member 62 attached to each transfer member 46. Plate 70 is secured to gear member 72 which, in turn, is rotationally driven by motor 74. As motor 74 turns gear member 72 and bottom plate 70, vertical drive members 68 rotate with bottom plate 70 and thereby drivingly rotate lateral members 62 and attached vertical members 46 and rollers 64. [0020] Vertical drive members 68 allow lateral members 62 to slide vertically relative to drive members 68 as members 62, 68 rotate. Furthermore, vertical drive members 68 have a height that is sufficient to retain members 62, 68 in mutual contact for a full rotation of members 62 about barrel cam 58. Camming groove 60 is used to control the vertical height of rollers 64, and thus lateral members 62 and transfer members 46, as rollers 64 and attached members 62, 46 rotate about machine axis 76. Gear member 72, bottom plate 70 and barrel cam 58 are also centered on machine axis 76. The operation of camming groove 60 is best understood with reference to Figure 10. Figure 10 represents the radially inner surface 59 of barrel cam member 58 in a linear format. A 5 x 84 grid pattern is shown in Figure 10 for purposes of explanation only. In the illustrated embodiment, groove 60 is designed for use with a stator core having 84 slot 22/tooth 24 pairs. Each of the 84 lateral positions depicted in Figure 10 corresponds to a particular circumferential position relative to axis 76. Thus, the progression of roller 64 from one lateral grid member to next adjacent lateral grid member constitutes the incremental rotation of roller 64 about machine axis 76. As each roller 64 rotates, the vertical transfer member 46 coupled to that particular roller 64 will also progressively rotate about machine axis 76. [0021] Furthermore, stator core 20 is mounted in holding plate 78. A motor 80 rotatingly drives holding plate 78 through shaft 80 and a gearing or belt arrangement which is not illustrated in Figure 5. Motor 80 rotates holding plate 78, and stator core 20 mounted therein, at the same rotational speed as transfer members 46 to maintain a proper alignment between stator core 20 and transfer members 46. Motor 43 rotates wire drum 42 so that the tangential velocity of wire pack 30 on drum 42 is the same as the tangential velocity of wiring positioned on transfer members 46 to thereby facilitate the transfer of wire pack 30 from drum 42 to transfer members 46. An electronic controller is used to maintain motors 43, 74 and 80 at the appropriate speeds. In alternative embodiments, a single motor, with an appropriate gearing or drive belt arrangement, could replace the three motors 43, 74 and 80. It is also noted that, although not depicted in the Figures, motor 80 can also be employed to power a second unit for installing windings on a stator core.

[0022] The vertical positioning of transfer members 46 is controlled by camming groove 60 which extends at constant slopes between four transition points 60a, 60b, 60c and 60d as shown in Figure 10. The different segments of camming groove 60 defined by these transition points each have a separate function. The camming groove segment between transition points 60a and 60b is horizontally oriented and extends for a limited length (6 of 84 horizontal grid units). This segment of camming groove 60 is positioned to correspond to the location at which transfer members 46 interact with wire drum 42 and pick wiring from the drum 42. The horizontal orientation of camming groove 60 between points 60a and 60b maintains transfer members 46 at a constant vertical height as they rotate into engagement with the wire pack 30 positioned on wire drum 42. As an individual roller 64, and its attached transfer member 46, rotates through the camming groove segment 60a-60b, the transfer element 46 will engage end turns 36 of wires 32 in the slots 48 of transfer element 46 and will separate that portion of wire pack 30 from drum 42 by the time that transfer element 46 reaches transition point^'60b. Transfer member 46, together with its attached wires 32, will then move through camming groove segment 60b-60c. Camming groove segment 60b-60c defines an inclined path and vertically raises the transfer member 46 with its attached wires 32.

[0023] When transfer member 46 has reached transition point 60c in camming groove 60, the transfer member 46 will be properly positioned for wires 32 held by the transfer member 46 to be pushed outwardly into engagement with stator core 20 as schematically illustrated in Figure 9 and discussed above. Transfer member 46 will remain properly positioned for this transfer of wires 32 to stator core 20 for the full length of camming groove segment 60c-60d during which time, the wires 32 positioned on the transfer member 46 can be installed onto stator core 20. After wires 32 have been removed from transfer member 46 and installed on stator core 20, the transfer member 46 will reach the transition point 6Od. The camming groove segment 60d-60a rapidly drops the now empty transfer member 46 to a level at which it can interact with wire drum 42 and pick up another portion of wire pack 30 for installation in stator core 20. As seen in Figure 10, the vertical slope of segment 60d-60a is much greater, i.e., steeper, than the slope of segment 60b-60c. The reduced slope of segment 60b-60c allows the wire pack 30 to be lifted into place within the interior of stator core 20 (by forming it into a partially spiral shape) while still maintaining the relative positions of the individual wires 32, 32a forming wire pack 30. [0024] Wire pack 30 may have a length that corresponds to several layers of wiring in stator core 20 and, to fully install windings in stator core 20, a corresponding number of rotations of stator core 20 and transfer members 46 will be required to install wire pack 30 on core 20. In other words, when wire pack 30 is in a flat configuration as shown in Figure 2, it may define a number of slot segments 34 along its linear length that is greater than the number of slots 22 in stator core 20. Furthermore, in other embodiments, the windings installed in stator core 20 could be formed by multiple wire packs 30. For example, a first wire pack 30 could be placed on drum 42 and then installed in the outer radial portion of slots 22 in stator core 20. Then, a second wire pack 30 could be mounted on drum 42 and installed in the inner radial portion of slots 22 in stator core 20 as a second manufacturing operation.

[0025] It is noted that although only three rollers 64 and associated lateral members 62 are depicted in Figure 6, rollers 64, lateral members 62 and vertical members 46 fully circumscribe axis 76 with one set of such members being aligned with each tooth 24 in stator core 20. As can be seen in Figure 5, the upper ends of transfer members are located within groove defined by upper guide cylinder 84 which allows vertical members 46 to reciprocate vertically while maintaining vertical guide members in a proper orientation as they rotate about axis 76. [0026] While this invention has been described as having an exemplary design, the present invention may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles.

Claims

WHAT IS CLAIMED IS:

1. An apparatus for mounting wiring on an electrical motor or generator core, the apparatus comprising: a rotatable wire drum for holding a wire pack to be mounted; a plurality of transfer members that are rotatable with said wire drum and operable to capture the wire pack on a individual slot segment basis, said transfer members adapted to form the wire pack into a partial spiral shape and axially translate the wire pack to the core to be mounted with the wire pack; a plurality of insertion fingers rotatable with the core and said transfer members, said transfer members adapted to locate the wire pack on and individual slot basis with the core, said insertion fingers adapted to transfer the wire pack from said transfer members into said core on an individual slot basis.

2. The apparatus of Claim 1 in which the wire pack is formed of non-circular wire.

3. A method of mounting wiring on an electrical motor or generator core having slots, comprising the steps of: placing a wire pack on a wire drum; rotating the wire drum with a series of transfer members to effect transferring the wire pack to the transfer members on a individual slot segment basis. forming the wire pack in a partial spiral shape with the transfer members; rotating the electrical motor or generator core with the transfer members and inserting the wire pack into the slots of the electrical motor or generator core.