Methods and apparatus for making stators for electric motors and the like, and improved terminal boards therefor

Abstract: The axial end portions of the insulating members which are used to line the longitudinal channels formed between circumferentially adjacent, radially inwardly projecting poles in a stator (e.g., an electric motor stator) are protected from damage by the wire being wound by providing terminal boards at each axial end of the stator having por­ tions which overhang the axial ends of the insulat­ ing members. Temporary wire grippers may also or alternatively be mounted on the axial ends of the stator (e.g., on the above-mentioned terminal boards) for temporarily holding the leads of the stator coils prior to permanent termination of those leads on permanent terminals on the terminal boards.

Description: Background of the Invention This invention relates to methods and apparatus for making stators for electric motors and similar machines such as generators. Although the invention is described herein in the context of its application to electric motor stators, it will be understood that it is equally applicable to other types of stators such as have been mentioned. Terminal boards for electric motor stators are insulating members which are typically placed on both axial ends of the main stator body for such purposes as supporting the axial ends of the windings wound on the poles of the stator and providing insulated attachment points for the terminals at which the ends of the coil wires can be connected to wires external to the stator. In some electric motor stators the ends of the coil wires (i.e., the so-called start and finish leads) are anchored directly in the terminal receptacles on the terminal board (see, for example, Pearsall U.S. patent 4,074,418). Metal terminals are then pushed into the receptacles to make electrical contact with the coil wires. In other motors, however, the ends of the coil wires must be held temporarily during and after winding. At a subsequent termination station the ends of the coil wires are relocated to terminals mounted on the terminal board. In the past, the elements for temporarily holding the ends of the coil wires have been provided on the pallets or other structures which support and/or convey the stators (see, for example, Wheeler U.S. patent 4,612,702, Nussbaumer et al. U.S. patent 4,679,312, and Santandrea et al. U.S. patent 4,713,883). Providing elements for temporarily holding the ends of the wire coils on the pallet or other coil supporting structure (hereinafter referred to generically as a pallet) has a number of disadvantages. For one thing, these wire-holding elements complicate the pallet, thereby increasing its cost. The presence of these wire-holding elements around the stator also makes it more difficult to place the stator on or remove the stator from the pallet. The stator-handling elements which perform these tasks must be designed so that they do not interfere with the wire-holding elements. The need for wire-holding elements on the pallet may make it difficult or impossible to use the same pallet for stators of different size (e.g., different stack height). A substantial amount of wire may be needed to temporarily reach wire-holding elements on the pallet. This wire may have to be cut off and discarded when the wire is finally permanently terminated on the terminal board. The fact that the coil ends are temporarily attached to the pallet may make it more difficult or impossible to use certain permanent termination techniques which would otherwise be advantageous. For example, it may be difficult or impossible to employ permanent termination apparatus which requires removal of the stator from the pallet. EP 207386 provides solutions for winding spools and temporarily anchoring the initial end of a wire in wedge to prevent the wire from unwinding. On completition of winding the ends of the wires are placed in seats for receiving terminals. When these operations have been completed the spools are mounted on a magnetic core. This document does not disclose stators as processed by this invention and their related terminal boards nor does this document supply any teaching towards improving processing methods for the stators according to this invention. In view of considerations such as the foregoing, it is an object of this invention to provide improved apparatus, as claimed in claim 1, and methods as claimed in claim 5, for temporarily holding the ends of coil wires during and after winding the coils on the poles of a stator. Summary of the invention More particularly the objects of the invention are accomplished in accordance with the principles of the invention by providing stators (preferably terminal boards) having grippers for temporarily holding the ends of the coil wires so that these ends can be subsequently picked up and relocated to terminals permanently mounted on the terminal board. This has a great many advantages including facilitating processing of stators on and off pallets, simplifying the design of the apparatus which must handle the stator after winding but before the coils are permanently terminated, facilitating the design of apparatus which can handle stators of different sizes (e.g., different stack heights), and reducing wire consumption. Further features of the invention, its nature and various advantages will be more apparent from the accompanying drawings and the following detailed description of the preferred embodiments. Brief Description of the Drawings FIG. 1 is an axial and view of an illustrative embodiment of a stator constructed in accordance with the principles of this invention prior to winding coils on the stator poles. FIG. 2 is an enlargment of a portion of FIG. 1. FIG. 3 is a detail view taken along the line 3-3 in FIG. 2. FIG. 4 is an elevational view of an alternative embodiment of apparatus constructed in accordance with this invention. FIG. 5 is a view taken along the line 5-5 in FIG. 4. FIG. 6 is a partly sectional view of a stator constructed in accordance with this invention mounted on a pallet. FIG. 7 is a partly sectional view of a stator constructed in accordance with this invention mounted in a alternative way on an alternative pallet. FIG.8 is a sectional view taken along the line 8-8 in FIG. 7. FIG. 9 is a flow chart of stator making methods in accordance with this invention. FIG. 9 is also a schematic block diagram of stator making apparatus in accordance with this invention. Detailed Description of the Preferred Embodiments FIG. 1 shows a terminal board 20 constructed in accordance with this invention and mounted on an axial end of a stator 10. Terminal board 20 is a complete annular ring, although it could also be made up of two or more semiannular (meaning partly annular) segments. Behind terminal board 20 in FIG. 1 is the stack of metal laminations 12 (see FIG. 6) which forms the main body of the stator. Terminal board 20 itself is typically made of an insulating material such as plastic. Terminal board 20 typically includes terminal receptacles (e.g., receptacles 22a-d), at least some of which hold or will receive metal terminals (e.g., terminal 50 in FIG. 6) to which the ends of the stator coil wires are attached to facilitate making electrical connections to the stator. (The terminal receptacles 22 shown in the drawings are for terminals of the type which are generally inserted when the stator is in the termination station after the coils have been wound. The depicted terminals 50, on the other hand, are of a type which are generally inserted before the terminal board is applied to the stator. These two different types of apparatus are depicted merely to make it clear that the present invention can be used in either case.) In the depicted illustrative embodiment, stator 10 has two poles 14a and 14b, although it could have more poles if desired. In front of each pole 14 terminal board 20 has a coil holder 24a, 24b which extends axially outward from the portion of the terminal board which is adjacent to the surface of the pole that is concentric with central longitudinal axis 16. At the axial end of each coil holder 24 which is remote from the main annular portion of terminal board 20 each coil holder has a coil retainer tab 26a, 26b which projects radially outward from the associated coil holder. Before terminal board 20 is mounted on stator stack 12, an insulating member, insert, or liner 30a, 30b is pushed axially into each channel which exists between circumferentially adjacent stator poles. Each insert 30 is preferably axially somewhat longer than the stator stack (excluding terminal boards 20) so that each insert projects slightly from each axial end of' the stator stack prior to attachment of terminal boards 20. After inserts 30 are in place, a terminal board 20 is mounted on each axial end of the stator stack as shown in FIG. 1. According to the invention, wire grippers 90 are mounted on one or both axial ends of the stator (e.g., by being mounted on one or both of terminal boards 20 as shown in FIGS. 1 and 2) for temporarily holding a coil lead prior to permanent termination of that lead on the terminal 50 in an adjacent terminal receptacle 22. Grippers 90 can be at any convenient locations on ends of the stator or the associated terminal boards 20. After the stator has been wound, it is typically passed from the winding station to a terminating station. In the terminating station, each coil lead is removed from its gripper 90 and permanently terminated on a terminal 50 in a terminal receptacle 22. Although various gripper constructions can be used, FIGS. 1, 2, and 3 show one illustrative form of gripper 90 which is integral with terminal board 20. Gripper 90 has two upstanding members 92 and 94 with a slot 96 therebetween. The smallest portion of slot 96 is narrower than the diameter of the wire lead 72 to be held in gripper 90. Accordingly, wire lead 72 can be pushed down into slot 96 which then holds the lead until it is subsequently lifted out and relocated to a terminal 50 in an adjacent terminal receptacle 22. The number of grippers 90 will typically correspond to the number of leads to be temporarily held, although additional grippers 90 may be provided in the event that a lead is to be temporarily anchored in a first gripper, then relocated to one or more other grippers before being finally terminated on a terminal 50. Note that some motors are made with more than one coil per pole, and/or with coils having intermediate taps. Grippers 90 can be used for the start, intermediate (if any), and finish leads of each coil. If desired, after they have performed their temporary wire-holding function, grippers 90 can be knocked off or otherwise removed from the stator. For example, FIGS. 4 and 5 show an alternative gripper 190 which is not integral with terminal board 20. Instead, gripper 190 is a separate element which can be plugged into a simple hole in terminal 20 (or stator body 12 if the gripper is at a location not covered by terminal board 20) by means of pin 198. As in the case of gripper 90, a wire lead can be temporarily held in slot 196 between upstanding members 192 and 194. At the appropriate time, the wire lead can be removed from slot 196 and permanently secured to a terminal 50. Thereafter, gripper 190 can be removed from the stator (e.g., by pulling pin 198 out of the associated terminal board hole or by shearing gripper 190 off above pin 198). The placement of grippers 90 or 190 (hereinafter referred to generically as grippers 90) on stator stack 12 or terminal board 20 rather than on the pallet or other apparatus which holds the stator during processing has several important advantages. For example, FIG. 6 shows stator 10 being transported vertically on pallet 120 having pin 122, central column 124, and peg 126 for positioning the pallet with the required precision. In FIG. 6 coils 70 have been wound on the stator, leads 72 are temporarily secured in grippers 90, and terminals 50 are in place but not yet connected to wire leads 72. Accordingly, FIG. 6 shows stator 10 as it might be conveyed on pallet 120 from a coil winding station to a lead terminating station. Because leads 72 are held in grippers 90 on the stator rather than in elements mounted on pallet 120, stator 10 can be readily placed on or removed from pallet 120 at either or both of the winding and lead terminating stations. The area around the stator is not cluttered by lead-holding elements, thereby simplifying the design of the apparatus required to remove the stator 10 from pallet 120 or to place the stator back on the pallet. The amount of lead wire required to reach the wire-holding elements is also reduced by having the elements (i.e., grippers 90) right on the stator. And if it is desired to process stators (e.g., stators 10′) of a different size (e.g., a different stack height), no changes or considerably fewer charges are required to pallet 120 than if wire leads 72 were held by elements on the pallet. FIGS. 7 and 8 show that similar advantages obtain when stator 10 is transported horizontally on pallet 120'. Such horizontal transport may be advantageous in certain situations (e.g., when leads are to be terminated at both ends of the stator). As has been mentioned, FIG. 9 is a flow chart of the stator making methods of this invention. FIG. 9 is also a block diagram of the stator making apparatus of this invention. In step or station 100 stator stack or body 12 is provided in any conventional manner. In step or station 102 insulating members 30 are inserted in the longitudinal channels which are present in the stator between circumferentially adjacent poles. This step or station can also be conventional (see, for example, Luciani et al. U.S. patent 4,831,716 which shows suitable apparatus of this kind). In step or station 104 terminal boards 20 are attached to the axial ends of the stator body in any conventional manner. One or both of these terminal boards may include wire grippers 90. Alternatively, wire grippers 90 may be mounted directly on stator body 12 in step or station 104. In step or station 106 coils are wound on the stator poles. European patent publication n° 0387411 in the name of this Applicant shows apparatus suitable for manipulating the start and finish leads of stator coils. This or other known apparatus can be readily adapted to deposit the start and/or finish leads of the coils in wire grippers 90 if desired. (Of course, if wire grippers 90 are not needed and the start and finish leads can be anchored directly in terminal receptacles 22, then other known apparatus such as that shown in Pearsall U.S. patent 4,074,018 can be used in step or station 106 for handling the start and finish leads.) Various known coil winding needle structures and motions can be used to actually wind the coils in step or station 106 (see, for example, Wheeler U.S. patent 4,612,702 and Luciani U.S. patent 4,762,283 which show suitable needle structures and motions). Following step or station 106, the stator is typically moved from the winding station to a terminating station 108 where the start and finish leads are terminated or where the termination of those leads is completed. For example, if the start and finish leads have been anchored directly in terminal receptacles 22 as in Pearsall U.S. patent 4,074,418, then in step or station 108 a metal terminal is typically pushed into each terminal receptacle in the known manner to make contact with and complete the termination of each lead. On the other hand, if the coil leads are being temporarily held by wire grippers 90, then in step or station 108 each such lead is removed from its wire gripper and transferred to the appropriate permanent metal terminal. The known apparatus for transferring such leads from the wire grippers on pallets or other stator holding apparatus to permanent terminals as in Wheeler U.S. patent 4,612,702, Nussbaumer et al. U.S. patent 4,679,312, and Santandrea et al. U.S. patent 4,713,883 can be readily modified to transfer leads from wire grippers 90 to permanent terminals 50. Note that the principle disclosed in Santandrea et al. U.S. patent 4,713,883 of winding and terminating the stator on the pallet can be used with this invention if desired. If wire grippers 90 have been used, and if it is desired that they not remain on the finished stator, then in step or station 110 wire grippers 90 may be removed by any suitable technique such as by shearing them off or by pulling them out if they are plugged into the stator. It will be understood that various modifications can be made by those skilled in the art. For example, wire grippers 90 can be mounted directly on stator stack or body 12 or can be mounted on terminal boards 20 as explained above.

Claims: A terminal board for use on an axial end of a hollow, annular stator body (10), said stator body having poles (14) which extend radially inwardly into the interior of said stator body so that at least one coil of wire (70) having at least a start lead and a finish lead can be wound around each pole while the terminal board (20) is in place on the stator body, the opposite axial ends of each coil (70) protruding respectively from the opposite axial ends of the stator body, said terminal board (20) having at least one permanent terminal receptacle (22) associated with each of said poles, each of said permanent terminals (22) being for a permanent termination of one of the leads (72) of the coil of wire (70) on the associated pole and each of said permanent terminals being on the face of said terminal board (20) which faces axially away from the axial end of the stator body on which the terminal board is mounted, and said terminal board being characterised in that it comprises at least one wire gripper (90, 190) associated with each of said poles (14) for temporarily holding said one of said leads (72) of the coil of wire (70) on the associated pole prior to removal of said lead (72) from said wire gripper (90, 190) and attachment of said lead to said permanent terminal (22); each of said wire grippers (90, 190) and the relevant permanent terminals (22) being spaced from each others on said terminal board (20). A terminal board according to claim 1 characterized in that each of said wire grippers (90, 190) project axially out from said face of said teminal board (20) which faces axially away from the axial end of the stator body (10) on which the terminal board is mounted. A terminal board according to claim 1 characterized in that each of the grippers (90, 190) comprises: first and second members (92, 94-192, 194) separated from one another by a slot (96, 196) for receiving said at least one of said leads (72), the spacing between said first and second members (92, 94-192, 194) being less than the diameter of said at least one of said leads (72) so that it can be releasably retained in said slot (96, 196). A terminal board according to claim 1 characterized in that the grippers (90) are removable from said stator body (10). The method of making a stator comprising the steps of: providing a hollow annular stator body (10) having a longitudinal axis and at least one radially inwardly projecting pole (14) and an apparatus for holding said stator during processing, mounting a terminal board (20) on at least one axial end of said stator body transverse to said longitudinal axis, said terminal board having at least one terminal receptacle (22); winding said pole with a coil of wire (70) having start and finish leads (72) extending from portions of said coils protruding beyond the axial end of said stator body; temporarily securing said leads (72) prior to terminating said stator; terminating said stator by moving said stator to a termination station where said leads (72) are transferred and permanently secured to said terminal receptacles (22) in a region which is axially beyond the axial end of said stator body; the method being characterized by the following steps: prior to terminating said stator and in order to temporarily secure at least one of said leads (72), temporarily securing at least one of said leads extending from said protruding portion of said coils (70) in a wire gripper (90, 190) mounted on said at least one end of said stator body at a location spaced from said terminal receptacle (22) of said terminal board (20) in a plane transverse to said longitudinal axis, to avoid mounting said grippers on said apparatus for holding said stator; terminating said stator by transferring said at least one lead (72) from said wire gripper (90, 190) mounted at said location of said stator body to said terminal receptacle (22) for receiving the leads in said region which is axially beyond said axial end of said stator. The method dedined in claim 5 further comprising the steps of: removing said wire gripper (90, 190) from said stator body (10) after performance of said transferring step.

Inventors: SANTANDREA LUCIANO, SANTANDREA, LUCIANO
Applicants: AXIS SPA, AXIS S.P.A.
Application year: 1990
Main classification: H02K3
IPC codes: H02K15, H02K3