Adjustable Cone Member for Electrical Coil Formation

1. Field of the Invention

This invention relates to electrical coil bars of dynamoelectric machines, and more particularly, to means for shaping the end portions of those coil bars.

2. Description of the Prior Art

Stator windings for dynamoelectric machines such as motors and generators often include a plurality of phase coils which are each formed by inserting a plurality of axially extending conductors or coil bars in a stator core and connecting selected coil bars at their ends. Such connections are generally made in the end turn regions of the stator and are called series connections. Such series connections join circumferentially separated coil bars necessitating coil bar angular displacements in the stator end turn regions for each joined pair of coil bars. Due to considerations such as the circumferential separation between connected coil bars, space limitations in the end turn regions, and avoidance of interference with other structural elements in the stator end turn regions, the stator coil bars are frequently bent radially outwardly, circumferentially about, and finally generally parallel with the axis of rotation of the particular machine's rotatable shaft. Assembly of such bent coil bars in dynamoelectric machines results in formation of frusto-conical surfaces in the dynamoelectric machine's end turn regions.

Prior coil forming techniques included the use of concave and convex forming blocks, frequently made of wood, which provided the foundation against which the conductors or coil bars were deformed so as to properly shape them through hammering, pushing, twisting, and bending. Such coil bar formation has traditionally been accomplished manually with considerable effort and has resulted in the lack of shape uniformity among coil bars since there was no way to accurately control the manual forces being applied. Such imprecise shape duplication of coil bars causes difficulties in both winding and serially connecting the coil bars. Such difficulties can adversely affect the utilizing machine's cost and quality and the lack of shape uniformity can promote non-interchangeability of replacement parts and decreased reliability due to residual stresses imposed on the coil bars. A further disadvantage of such prior art forming blocks is the vast amount of storage space needed to house the many different sized blocks required by the different sized dynamoelectric machines during times of non-usuage.

Copending W. E. Case No. 47,316, filed Sept. 23, 1977, having Ser. No. 836,172, and assigned to the assignee of the present invention discloses an apparatus for producing coil bar shapes by wrapping them around a convex, frusto-conically shaped member. Such disclosure teaches a solid mass of material constituting the frusto-conical shape. A disadvantage in using such member is that its major and minor diameters and thus the cone angle are fixed for each frusto-conical member. Since different dynamoelectric machines have different stator sizes and different coil bar cone angles, the solid frusto-conical member disclosed in the copending application can require vast amounts of storage space between times of actual usage in forming coil bars. An additional disadvantage of the aforementioned solid forming member is that it can be used in the forming apparatus for only one size dynamoelectric machine, necessitating the forming machine's disassembly and insertion therein of another forming member whenever coil bars are to be made for a different sized dynamoelectric machine.

As such, it would be advantageous to use a coil bar forming apparatus which had an adjustable frusto-conical coil shaper which was adaptable to different size dynamoelectric machines and the coils' cone angles required therein.

In accordance with the present invention, an improved apparatus is provided for forming electrical coil bars for dynamoelectric machines. The invention generally comprises means for bending a first end portion of a coil bar at selected angels from an adjacent coil portion, a rotatable member of frusto-conical shape whose cone angle is adjustable to any said selected angles, means for rotating the rotatable frusto-conical member through selected angular displacements, and means for guiding the coil bars end portion against the conical surface of the rotatable member in a spiral configuration about its axis of rotation during angular displacement of the frusto-conical member. In a preferred embodiment of the invention the rotatable, frusto-conical member constitutes a shaft disposed along the member's axis of rotation, a plurality of radially extensible struts situated at one end of the shaft, a plurality of support members situated at the opposite end of the shaft, and a plurality of shaping ribs pivotally mounted at one end to the struts and slidably mounted at their other ends to the support members. Such coil bar shaping apparatus may be used on both ends of unshaped coil bars for simultaneously shaping those ends into suitable configurations for use in dynamoelectric machines.

The invention will be more fully understood from the following detailed description of the preferred embodiment, taken in connection with the accompanying drawings, in which:

FIG. 1 is an end view of the preferred embodiment of an electric coil bar forming apparatus;

FIG. 2 is an elevation view of the apparatus illustrated in FIG. 1;

FIG. 3 is a plan view of the apparatus illustrated in FIG. 1; and

FIG. 4 is an additional embodiment of the invention.

The present invention is concerned primarily with shaping apparatus for electrical coils of dynamoelectric machines. Specifically, the present invention is intended to be a component of the invention described in Ser. No. 836,172, whose applicants are M. Kolesar and H. Rettger. The aforementioned, copending patent application was filed Sept. 23, 1977 and is hereby incorporated by reference.

A rotatable frusto-conical member 10 of adjustable cone angle is rotatable about axis 12 on shaft 14. A lead bend block and associated assembly 16 is disposed on drop bend bar 18 as it was in the aforementioned copending patent application. The coil workpiece which is formable on the present invention is not shown in FIGS. 1 through 3, but it is to be understood that such coil cooperates with the previously-mentioned forming components and cell bend-drop bend radii former 20, illustrated in FIG. 3, in the same manner as did the coils in the copending patent application.

Since FIGS. 1, 2, and 3 are axial, side, and plan views respectively, the component parts of the present invention's adjustable cone and their relative configuration may be more effectively understood by viewing FIGS. 1 through 3 simultaneously rather than sequentially. Face plate 22 situated at one axial end of shaft 14 provides a structural foundation against which radially-extensible struts 24A and 24B are securable. Struts 24A and 24B are alternated in the circumferential direction and are disposed on opposite axial sides of face plate 22 so as to permit greater ranges of radial extension than would be possible if such struts were disposed on one axial side only of face plate 22. The extensible struts 24A and 24B are preferably secured to face plate 22 by threaded fasteners appropriately disposed to permit loosening and tightening thereof from the more accessible side of face plate 22. Slots formed in struts 24A cooperate with threaded openings in face plate 22 to receive threaded fasteners 26 and thus permit radial extension thereof to predetermined distances whose radial extents are limited by the length of slot. Struts 24B have threaded holes disposed therein which cooperate with slots formed in face plate 22 to receive threaded fasteners 26. Disposal of such threaded openings in struts 24B and slots in face plate 22 provide capability for radially-extending struts 24B to predetermined locations. The threaded openings in struts 24B are separated by distances less than or equal to the length of the cooperating slots in face plate 22.

Pivotably mounted at the radially outer ends of struts 24A and 24B are shaping rib members 28. Support members 30 extend radially from shaft 14 and are spaced circumferentially thereabout to be in general alignment with struts 24A and 24B. Translation blocks 32 are slidably disposed on shaping rib members 28 with each block having a threaded opening therein which, when generally aligned with the support member's slot 33, can receive a threaded fastener therein. Shaping ribs 28 form a frustoconical member whose minor diameter may be selectively adjusted by radially-extending struts 24A and 24B and whose major diameter may be independently adjusted by pivoting shaping rib members 28 at the radially outer end of the strut members and securing translation blocks 32 at a selected radial distance from shaft 14 along slots 33 of support members 30.

After the desired positioning of struts 24A and 24B and the disposition of translation blocks 32 relative to support members 30, the coil formation process as detailed in the copending patent application may be performed. Face plate counter balance member 34 and the frustoconical member's counterbalance 36 are disposed to reduce the torque necessary to rotate shaft 14 and shape the coil members in question. Frustoconical shaft 14 is reduced in radial extent at each axial end of the frustoconical member to be mateable with bearings supported by the front bearing pedestal 38 and rear bearing pedestal 40. The torque required for shaping the coil members is preferably supplied to shaft 14 through sprocket 42. As can be seen from viewing FIGS. 1 through 3, shaping rib members 28 and support members 30 decrease in length as the rib members' angular displacement from drop bend bar 18 increases. In the illustrated example of FIGS. 1 through 3, shaft 14, as viewed in FIG. 1, is operationally rotatable in the counterclockwise direction. It is to be understood that while shaping ribs 28, support members 30, and axial separation distances between the struts and support members 30 vary in length, the aforementioned components could be fabricated to have equal lengths. However, such varying of lengths is useful for reducing the weight of the apparatus, decrease material requirements for its manufacture, and increase the strength of some of its members. While the aforementioned, copending patent application utilizes a relatively smooth frustoconical forming surface, it has been found that discontinuous surfaces such as are formed by shaping ribs 28 of the present invention provide a forming surface more than adequate to precisely shape coil bars for insertion in dynamoelectric machines.

FIG. 4 illustrates an alternate mounting method for connecting shaping ribs 28 to support members 30. Slots formed in both of the aforementioned members are capable of receiving a fastener therethrough. By pivoting one end of shaping ribs 28 on struts 24B, the other end of shaping rib 28 may be moved relative to support member 30 and secured in position by tightening the threaded fastener disposed through the cooperating slots. The extreme positions A and B illustrate the range of major cone diameters to which the apparatus is adaptable. While only single shaping apparatus 10 has been illustrated, it is to be understood that two such apparatus 10 could be utilized on opposite ends of each coil bar to permit simultaneous coil bar end formation.

It will now be apparent that an improved coil bar shaper apparatus has been provided in which the frustoconical former may be infinitely adjusted within predetermined limits to produce frustoconical surfaces of selected cone angles. Such adjustable shaping feature results in a shaping apparatus whose forming surfaces can be altered to comply with the requirements of any dynamoelectric machine without changing components of the apparatus when forming coils for different sized dynamoelectric machines.