IMPROVEMENT IN THE ARRANGEMENT FOR THE INSERTION OF COILS IN A STATOR

Abstract: Arrangement for the insertion of coils in a stator comprising a moving wire-insertion spider, a plurality of parallel wire-guide blades arranged along the contour of said moving spider, a stack-guide member provided with a plurality of recesses accomodating respective blades which are provided with a groove on their outer surface. Said recesses are provided with a rib protruding towards the interior of the respective recess and extending parallelly to the longitudinal direction thereof, and are adapted to engage respective grooves when the stack-guide member is inserted within said wire-guide blades. In a preferred manner, said grooves are arranged in pairs on a respective blade and are symmetrical with respect to a vertical plane passing through the axis of said moving spider.

Description: IMPROVEMENT IN THE ARRANGEMENT FOR THE INSERTION OF COILS IN A STATOR DESCRIPTION The present invention refers to an improved airangement foi the insertion of the electric coils in the statoi of an electric motoi with the use of automatic equipment The statoi m elect- IC motois is commonly known to be made up substantially by two basic stiuctures, le the stator stack and the vanous coils of electnc wnes that are appiopi lately mseited m the respective slots piovided in said stator stack During statoi manufacturing, use is made of automated machines along with assembly tools and processes which are specifically developed and designed foi the insertion of the vanous coils of electnc wires into the respective slots of the statoi stack Such a 'dedicated' equipment includes a tool which is geneially known m the art as "coil insertion tool" and is formed by - a moving insertion spider provided with moving wire-guide blades, - a container of stationaiy wne-guide blades, - an insertion blade stack guide These terms aie generally known to those skilled m the ail, however, considering the the mattei being dealt with heie is a very specialistic one, in oider to promote a better understanding of the following descnption the basic elements of the above cited tool shall be particularly stressed below by using the same terminology as the one used throughout the following description and the appended claims MOVING INSERTION SPIDER This is a tool formed by a central rigid body, usually of metal and a substantially cylindrical shape, the side surface of which is provided with a plurality of recesses that aie legularly spaced out fiom each other, these lecesses have an elongated shape, aie open on the side surface of said cylindrical body, and are ai ranged so as to enable then inner suiface, which is in the form of a luled surface, le a surface geneiated by the solely tianslatory, par allel motion of a stiaight line, to emerge, le come out at the bases of said cylindiical body In said lecesses theie are provided, m an alternate anangement, a plmality of wne-guide blades, which aie constituted by elongated membeis whose outer surface is again in the form of a l uled suiface and whose lespective axes are parallel to and equidistant fiom the axis of said cylmdiical body CONTAINER OF STATIONARY WIRE-GUIDE BLADES This membei is totally sirmlai to the above descnbed one, so that its descnption may be omitted heie foi leasons of conciseness Anyway, the physical configuration of these two membeis, and the dimensions theieof, are such as to make it possible foi the moving insertion spider to fit into said container of stationaiy wne-guide blades by simply mtioducmg said moving spider, fiom the side of said cylmdiical body into the cylmdiical space that is delimited externally by the bamei of the wne-guide blades ananged outside the cylindrical body of said contamei This is usually possible owing to the fact that the blades arranged on the contamei and the blades ai ranged on the moving spidei are piovided alternately with lespect to each othei , so that the blades of the moving spidei are able to fit into the recesses m the cylmdiical body of the container of stationary wn e-guide blades BLADE STACK GUIDE The blade stack guide is a cylindrical member formed by a rigid central body, usually of metal, whose side surface is provided with a plurality of recesses that are spaced out regularly from each other, these recesses have an elongated shape, are open on the side surface of said cylindrical body, and are arranged m such a manner as to enable their inner surface, which is in the form of a ruled surface, to emerge, le come out at the bases of said cylmdncal body In pi ctice, this blade stack guide is fully similar to the cylmdiical body that has been described m connection with both the moving spider and the stationary blade container Foi a moie complete information, it should be furthei noticed heie that the stiuctme of the moving spider is sometimes inserted and firmly locked in the contamei of stationary blades, so that the latter has outwardly a stmcture that makes it substantially impossible foi the two cylindrical bodies to be distinguished from each othei Such a vanant, howevei , is not lelevant to the pui poses of the piesent invention, so that its descnption may be omitted heie foi reasons of greater clearness The pioceduie followed to assembly the coils m the statoi is described shortly below - for a start, the moving spider is inserted to the desired depth into the container of stationaiy blades, wheieas it will be appieciated that, m the case that these two members aie already joined to each other, this phase is of course omitted, anyway, a coriespondmg plurality of parallel gaps extending in the lengthwise diiection of the blades aie cieated between the stationaiy blades and the contiguous moving blades, - thereupon, the coils are appiopnately inserted, m a basically pei se known mannei , into said gaps with the related wnes that distiibute up to a certain height withm and along said gaps, - then the blade stack guide is mounted within the perimeter delimited, on the opposite side with respect to the cylindrical body, by the extreme portions of the same blades; this is obviously allowed for by the fact that the recesses in the blade stack guide are provided so as to be able to accomodate said extreme portions of the blades, so that the guiding function of such blades m the following phase is ensured, - the coil insertion operation can at this point be started, which consists mainly in raising the moving spidei and allowing the same to fit into the slots of the stator stack that will have in the meantime been duly prepared and ar ranged It is exactly during this opei ation that, owing to the effect of the vanous combined forces and reactions, the blades can be noticed to be stressed into flexing, both outwardly and inwardly, and even into twisting Since these blades are provided, on then outwards facing edges, with two sharp corners, that we shall call "slot lining protection borders" here and have the task of fitting in between the inlet edges of the sheath (also called "slot lining") used to protect the slot, it cleaily ensues that even these piotective borders undeigo said Uexural and/oi torsional sti esses, le m pailicular against the wires of the adjacent wne coils This occunence gives usually rise to two kinds of drawbacks the first one derives from said bordeis being subject to lapid wear-out owing to the wires of the coils rubbing against them along almost the entne length theieof, it therefore becomes necessary for these tools to be replaced quite frequently and this fact puts heavy penalties m teims of costs consideimg both the unit cost of these tools and the quite significant numbei m which they are necessarily used m such an industrial piocess on a very large scale as it is usually lequned today foi a competitive pi oduction The second one of said diawbacks is due to the fact that said wires, by rubbing against said sharp comeis of said edges, are exposed to being scratched oi indented; in particular, it is their outer insulating enamel layer that is in this way most easily damaged, thereby makmg it easy for the coil to break down and causing adjacent damaged wires to short-circuit It would therefore be desirable, and it is actually a mam purpose of the present invention, to provide one or more improved arrangements that are not only capable of preventing said wne-guide blades from undergoing both outward and mward bending stresses and torsional stresses as coils are being inserted m the related statoi stack, but aie also simple, unexpensive, capable of being implemented with readily available techniques and means, and do not requne any modification to be mti oduced m the manufacturing process This aim is reached m the arrangements with the features as recited m the appended claims and descnbed below by way of non-limiting example with l efei ence to the accompanying di awmgs , m which - Figuie 1 is a median vertical-section view of a moving spidei -blade contamei -blade stack guide-statoi stack assembly duimg a coil insertion operation, - Figure 2 is a honzontal-section view of the stator stack as coupled with the contamei of stationaiy wue-guide blades, as well as with the moving insertion spidei , said sectional view being taken at the height of the blade stack guide, - Figuie 3 is an enlaiged view of a portion of the pieceding Figure, - Figure 3A is a view of a vanant m the shape of the blades and the lecesses of the blade stack guide with lespect to the solution illustrated m Figure 3, - Figure 4 is a honzontal-section view of the blade stack guide, - Figuie 5 is an enlarged horizontal-section view of a portion of the sole blade stack guide, - Figure 6 is a cross-sectional view of a typical, both stationary and moving blade according to the present invention, - Figure 7 is a front view of a blade according to the present invention In the couise of the following description the terms "blade" and "lamina" are used as synonyms, according to the teiminology that is currently used by those skilled m the art The basic idea behind the present invention is described below When lefeience is made to Figure 1 , the assembly illustrated theie as a cross-sectional view can be noticed to comp se following elements a) the stator stack 1 , b) the container 2 supporting the stationaiy wire-guide blades 6, c) the moving insertion spidei 3 with the related moving blades 7, d) the blade stack guide comprising a centi al cylmdi leal body 2 , e) the ai rangement support base 5 Such an assembly may howevei not be piovided with a moving insertion spidei 3 and the related moving blades 7, m such a case, the insertion of the coils is obtained through the simple motion of said container 2 with the related stationaiy wiie-guide blades 6, which therefoie remain stationaiy with lespect to their contamei , but become moving blades with lespect to said stator stack 1 In a geneially known mannei , at a certain point during the coil insertion piocess, the above cited assembly is mounted in, le applied to the stator stack 1 , which can be noticed to be also piovided with the slots 9 intended to accomodate the wu e coils With lefeience to Figuie 2, the stationaiy blades 6 and the moving blades 7 can be noticed to be an nged according to an alternate scheme with respect to each othei along a circular penmetei , and they are adapted to fit into lespective paiallel recesses 10 provided in a ci own-like anangement on the outside of the blade guide stack, the central body 22 of which is illustrated individually in Figures 4 and 5 Furthermore, Figuie 3 can be noticed to also illustrate in a clearly distinguishable mannei the so-called "slot lining protection border" 14 provided m pairs laterally on each blade, be it stationary or moving, which protrudes from the outei side edges of each blade and fits m between the slot insulation 17 inside the slot 9 and the radial portions 18 of said blade stack guide that delimitate the adjacent recesses on the opposite sides In oider to pi event the blades fiom flexing outwardly, which is the actual diawback to be eliminated, the piesent invention teaches to create a sort of anchoiage" which must howevei be capable of sliding to accompany the motion of the blade stack guide, between said stationary and moving blades 6 and 7 and the conesponding lecesses 10 piovided m a crown-like airangement along the outei penmetei of the cylmdiical body of the blade stack guide 4 Such an anchorage is cieated by both a particulai shape oi configuration of the hollow, le lnnei suiface of said lecesses and a conesponding shape or configm ation of the outer suiface of each single blade, so that these elements aie capable of engaging each other and, owing to the blade stack guide being a solid and rigid cylmdei , it ensues that both the stationaiy and moving blades, by engaging, albeit slidably, the lespective lecesses of said blade stack guide, are totally pi evented fiom flexing and twisting, thereby reaching the desired aim Such an anchorage may of course be also obtained by only creating an mteifeience between lecess and blade so that the lattei cannot be pulled out of the foimei said mteiference being able to be quite easily obtained by letting the concerned elements engage each othei m an "undeicut '-like mannei with respect to the radial diiection of the central axis of the blade stack guide which coincides with the axis "C" of the moving spidei Various forms and mannei s are of course possible m view of implementing such a slidable "anchorage" between recesses and blades, using either just a single anchorage element or even more elements A prefened solution is as illustrated in the Figures, in which said "slidable anchorage" is brought about exactly by means of said radial portions 18 In fact, these are provided, preferably m pairs and on the opposite sides thereof, le with respect to two adjacent recesses, with ribs 19 protruding into the corresponding recess of the blade stack guide Foi them to fit the desired purpose, said nbs 19 must be able to engage appiopnate conesponding giooves 20 piovided on the sides of both stationary and moving blades (Figuie 6) In an advantageous manner, in view of an improved manufactui ability, mterchangeability and assemblability of said blades, the respective giooves aie an anged in pans symmetrically with lespect to a vertical midplane "S" passing through the cential axis "C" of the moving spider It has been conoborated experimentally that, foi the blades to be imparted an adequate effect of lesistance to both outwaidly and inwardly directed flexural sti esses, as well as to toisional stesses, said giooves and lespective ribs must be piovided, le ananged in coirespondence of the tiansition zone between the stiaight profile "D", facing the extenoi of the lecess, and the curved piofile "F" situated m the inner part thereof, as illustrated m Figure 3A Said grooves 19 must furtheimoie be piovided with a tnangulai contour, and the cornei s 30 that are due to fit into the respective blade must have an angle 'ι " of at least 60° Howevei , if it is m particulai the 1 esistance of the blades to outwardly directed flexural stresses that has to be reached on a pnority basis, it is an advantageous solution if, with reference to Figures 3 and 6, said giooves 20 and said nbs 19 which aie so mutually engaged m pans mside the same recess, are provided with at least a suiface 23 of mutual I esistance that must be plane and oriented orthogonally (H) to the midplane "S" of the respective recess, so as to bring about a kind of engagement by mutual frontal opposition of the respective ribs and grooves Finally, considermg that the moving spider, when used or existing m the anangement, must be able to slide jointly with the respective moving blades within the crwon-like arrangement of stationary blades, and that the central body of this moving spider is provided with appropriate external recesses adapted to accomodate respective vertically sliding stationary blades, it is of particular advantage if also said external I ecesses existing in said central body of the moving spider are provided with similai engagement ribs as the ones existing m the blade stack guide, since when the moving spidei is raised to insert the wne coils, said centi al body of the moving spidei is in this way able to maintain the stationary blades, within which it is sliding, in their conect position, while m particulai preventing them from being forced into flexing outwardly It will be appieciated that the descnption and illustrations set forth above with leference to the accompanying drawings have been given merely as a non-limiting exemplification of the invention, and that any of a numbei of further valiants and modifications can therefore be devised and introduced without departing fiom the scope of the present invention

Claims: CLAIMS 1 Anangement for the insertion of coils m a stator stack (1), m which said anangement compnses - a contamei (2) supporting a plurality of stationary wn e-guide blades (6) arranged along the contour theieof, - possibly a moving wn e-msertion spidei (3) provided with a cential axis (C) and supporting a plurality of moving wne-guide blades (7), m which said stationary blades and moving blades are paiallel, said moving spider being slidable with lespect to said contamei (2), - a blade stack guide membei , piovided with a ligid, substantially cylindrical central body (22) on which there aie arranged a plmality of parallel I ecesses (10) adapted to accomodate respective stationaiy and moving blades, characterized in that said blades (6, 7) are provided, at least partially, with a groove (20) extending m the outer surface of the blade in a direction that is parallel to the length of the lattei , and that said recesses (10) are piovided with a respective rib (19) extending paraJlelly to the diiection of the length theieof, in which said ribs are facing the mteiior of the respective recesses and aie adapted to engage said respective grooves (20) when said blade stack guide is inserted into said wne-guide blades (6, 7) 2 Airangement for the insertion of coils in a statoi stack according to claim 1 , characterized m that said grooves (20) aie arranged m pairs on a lespective blade and aie symmetncal with respect to a lespective verdical midplane (S) passing thiough said cential axis (C) of said moving spider 3 Arrangement according to claim 2, characterized in that said recesses (10) are provided with respective pairs of ribs (19) extending parallelly to the axis of said blade stack guide and facing the interior of the respective recess, m which said nbs are adapted to engage lespective pairs of said grooves (20) when said blade stack guide is inserted into said wire-guide blades (6, 7) 4 Airangement according to claim 3, characterized in that said nbs and said grooves are oriented and sized so as to be capable of preventing said wire-guide blades (6, 7) from flexing and oi distorting when they are mutually engaged 5 Anangement according to any of the pieceding claims, characterized m that said blades and lespective 1 ecesses are piovided with a straight profile (D) facing the extenoi of the recess and a curved profile (F) situated m the internal part of the lecess, and that grooves and lespective nbs (19) aie ai ranged m the transition zone between said stiaight piofile (D) and said curved piofile (F) 6 Airangement accoidmg to claim 5 characterized in that said ribs (19) have a tnangulai shape and teiminate in a comei-like configm ation (30) and that the angle ® of said comer-like configm ations is more than 60° 7 Airangement according to any of the claims 1 to 4, characterized in that at least a contact surface (23) between said giooves and said nbs is plane and onented orthogonally (H) to the radius of said spidei passing thiough said central axis and the respective groove 8 An angement accoidmg to any of the preceding claims, m which said moving spidei is furtheimoie provided with a cential body, characterized in that said cential body is piovided with lespective external I ecesses adapted to accomodate lespective vertically slidable stationaiy blades, and that said I ecesses are piovided with ribs adapted to engage said grooves (20) of said stationary blades (6) so as to enable said stationaiy blades to be slidably associated to said central body of said moving spidei

Inventors: SARRO ALONSO JOSE, SARRO ALONSO, JOSE
Applicants: SARRO ALONSO JOSE, ZANUSSI ELETTROMECC, SARRO ALONSO, JOSE, ZANUSSI ELETTROMECCANICA S.P.A.
Application year: 1999
Main classification: H02K15
IPC codes: H02K15