ELECTRIC MOTOR STATOR END WIRE FORMING

Abstract: A device for compacting an annular bundle of windings projecting from the end of the body of a stator (9) of an electric motor. The device having means (8) for supporting and rotating the stator (9). An assembly of three rollers (18, 20, 22) are provided for compacting the windings. The first roller (18) being arranged to roll and compact the radially inner side of the bundle. The seconde roller (20) being arranged to roll and compact the radially outer side of the bundle. The third roller (22) being arranged to roll and compact the axial end face of the bundle. The three rollers (18, 20, 22) are adjustable to accommodate stators (9) of different sizes.

Description: ELECTRIC MOTOR STATOR END WIRE FORMING During the production of electric motor stators there is a requirement to compact the annular bundle of windings projecting from the end of the stator body into an envelope of predetermined size so that electrical clearances are maintained when parts are assembled to the end of the stator body. Traditionally the compacting has been carried out by a tool which is juxtaposed at the end of the stator and has radially movable shoes and an axial end ring for compacting the windings. In large volume production of small stators, the use of such tools is quite acceptable. However for larger size stators which are often produced in small numbers, it is generally uneconomical to provide large costly tools corresponding to each stator size, and indeed such large tools are extremely heavy and cumbersome to exchange when changing over from the production of one stator to that of another. Consequently it is not unusual for the windings of large size stators still to be formed and compacted manually, using a mallet. This obviously requires very skilled craftsmen and even then there is inevitable variation in the windings envelope from one stator to another. In accordance with the present invention, a device for compacting an annular bundle of windings projecting from the end of the body of a stator of an electric motor comprises a support for the stator; an assembly of three rollers; and means for rotating the assembly and the stator body relatively to one another about the axis of the stator; the first one of the rollers extending, in use, into the bundle and being arranged to roll and compact the radially inner side of the bundle; a second one of the rollers extending, in use, along the outside of the bundle and being arranged to roll and compact the radially outer side of the bundle; and a third one of the rollers extending, in use, across the end of the bundle and being arranged to roll and compact the axial end face of the • • bundle, the three rollers being adjustable to accommodate stators of different sizes. Although the first and second rollers may be contoured and the progressive compaction of the bundle in the 5 different directions achieved by moving the assembly of rollers and stator body axially of the stator body towards one another during compaction, means are preferably provided for advancing the first and second rollers radially outwardly and radially inwardly, respectively, of 0 the stator, and the third roller axially of the stator, during the compaction. The means for providing the radial movement of the first and second rollers and/or the axial movement of the third roller may be utilized not only for the progressive compaction of the bundle in the radial 5 direction, but also prior to compaction for the accommodation of stators of different radial and/or axial sizes. The rollers may be advanced by means such as a screw threaded drive but fluid operated rams are preferred. In each case the adjustment of the rollers to accommodate 0 a particular stator size, and the advance of all three rollers to produce progressive compaction of the bundle of windings, may be under numerical or other automatic control. The device can then be changed over from one stator size to another and carry out a compacting operation 5 with the minimum of operator involvement. In order to improve the compacting operation, two second rollers are preferably provided which are, in use, spaced apart around the outside of the bundle. The assembly of rollers could be mounted in a rotor 0 which is rotated, possibly even by hand, relatively to a stationary stator body. However this requires clearance for full rotation of all the rollers and in a more compact arrangement the stator body is rotated while contacted by the respective rollers at fixed radial positions. The 35 stator body may be rotated by being placed with its axis horizontal in a cradle formed by a pair or pairs of rollers which both support the stator body and transmit rotation to the stator body. Although the device so far described with three rollers will form one end of the stator, there may be two opposed heads each with the three rollers, for forming both ends of the stator simultaneously. In that event, and when the stator is arranged to be supported and rotated on a cradle of supporting rollers, the parts of the heads with the three compacting rollers are preferably swivelable away from one another to provide the space necessary for placing a stator on, and removing it from, the cradle. Furthermore, one of the heads may be mounted on a carriage which is movable towards and away from the other head to accommodate stators of different axial length. An example of a device, constructed in accordance with the present invention, is illustrated somewhat diagrammatically in the accompanying drawings, in which: Fig. 1 is a front elevation; and, Fig. 2 is a partial sectional elevation as seen from the line X - X in Fig. 1. The device has two heads A and B each of which has a base 4A and 4B, respectively. The base 4A is fixed and the base 4B is mounted on wheels 5 whereby the head B can be moved towards and away from the head A by the operation of a ram 6, the separation being measured on a scale 7. Each of the bases 4A, 4B carries a pair of rollers 8, the four rollers together forming a cradle to support a stator body 9. At least one roller of each pair is arranged to be driven by an electric motor 10 via a chain 11. Above the bases 4A, and 4B, each head has an assembly which is pivotally mounted on a fixed column 12 by means of a vertical pivot pin 13, so that it can swing away from the other head and clear from above its own supporting rollers 8, under the action of a ram 14. The assembly carries a pressing roller 15 which can be lowered on a pivoted arm 16 by means of a ram 17, into engagement with the top of the stator body 9, to hold the body down on the cradle of rollers 8, and hence to increase the friction by which rotation is transmitted from the rollers 8 to the stator body. Each assembly also includes a first lower compacting roller 18, which can be raised and lowered by means of a ram 19, two second upper compacting rollers 20 which can be raised and lowered by means of a ram 21 and a third end compacting roller 22 which can be moved by a ram 23. In use the upper assemblies of the heads A and B are unlatched and swung away from one another whereby a stator body 9 with unformed windings can be lowered onto the cradle rollers 8. The upper assemblies of the heads are then swung back to the position illustrated in Fig. 1 and the rams 16 are operated to bring the rollers down into bearing engagement with the top of the stator body. At this time the rams 19 and 21 will have been operated so that the rollers 18 and 20 are disposed respectively adjacent to the radially inner and outer surfaces of the respective ends of the winding bundle, and the roller 22 adjacent to the respective end of the winding bundle. Upon operation of the motors 10, the rollers 8 and stator body are rotated and the rams 19 and 21 are progressively operated so that the rollers 18 and 20 are respectively raised and lowered and come into contact with the radially inner and outer surfaces of the windings at the top of the bundle and progressively compress them to the required envelope. Simultaneously the rollers 22 are advanced by the rams 23 towards one another to compress the respective ends of the winding bundle to the necessary envelope. Upon completion of the forming operation the compacting rollers are retracted slightly, the upper portions of the heads are swung open and the formed stator is lifted off the rollers 8 to be replaced by a new one.

Claims: CLAIMS 1. A device for compacting an annular bundle of windings projecting from the end of the body of a stator (9) of an electric motor, the device comprising a support (8) for the stator; an assembly of three rollers (18,20,22); and means (8) for rotating the assembly and the stator body relatively to one another about the axis of the stator; the first one (18) of the rollers extending, in use, into the bundle and being arranged to roll and compact the radially inner side of the bundle; a second one (20) of the rollers extending, in use, along the outside of the bundle and being arranged to roll and compact the radially outer side of the bundle; and a third one (22) of the rollers extending, in use, across the end of the bundle and being arranged to roll and compact the axial end face of the bundle, the three rollers being adjustable to accommodate stators of different sizes. 2. A device according to claim 1, wherein means (19,21,23) are provided for advancing the first (18) and second (20) rollers radially outwardly and radially inwardly, respectively, of the stator (9) , and the third roller (22) axially of the stator, during the compaction. 3. A device according to claim 2, wherein the means for advancing the rollers (18,20,22) are fluid operated rams (19,21,23) . 4. A device according to any one of the preceding claims, wherein two second rollers (20) are provided, which are, in use, spaced apart around the outside of the bundle. 5. A device according to any one of the preceding claims, wherein the stator body (9) is rotated by being placed with its axis horizontal in a cradle formed by a pair or pairs of rollers (8) which both support the stator body and transmit rotation to the stator body. 6. A device according to any one of the preceding claims, wherein two opposed heads (A,B) are provided, each with the three rollers (18,20,22), for forming both ends of the stator (9) simultaneously. 7. A device according to claim 6, wherein the parts of the head (A,B) with the three compacting rollers (18,20,22) are swivelable away from one another to provide the space necessary for placing a stator (9) on, and removing it from, the cradle. 8. A device according to claim 7, wherein one of the heads (A,B) is mounted on a carriage (4B) which is movable towards and away from the other head to accommodate stators of different axial length.

Inventors: WHITBY LESLIE REX, WHITBY, LESLIE, REX
Applicants: WHITBY LESLIE REX, WHITBY TOOL & ENGINEERING COMP, WHITBY TOOL & ENGINEERING COMPANY LIMITED
Application year: 1993
Main classification: H02K15
IPC codes: H02K15