Apparatus for Winding Rotors of Electrical Machines

1. Field of the Invention

This invention relates generally to electrical motors and more particularly to an apparatus for winding rotors for such motors.

2. Background Description

In accordance with German Pat. No. 21 02 354 and U.S. Pat. Nos. 3,878,602 and 3,924,816, a multiple winding apparatus for motor rotors is known, wherein a rotor support has vertically located bores with bushings, into which the rotors may be set with their shaft end facing away from the collector. In the winding position, the rotors are pressed against locating ribs as soon as clamping heads are moved into their effective positions, wherein a spring-loaded ball is provided in the clamping head, the ball pressing into one of the grooves. The clamping heads are provided on their forward frontal surface with a recess, each adapted to the circumferential surface of the rotor packs. The recesses extend to the rotor grooves into which the wire is to be wound with the rotor being stationary, while the remaining parts adjacent to the recess of the frontal surface are shaped by beveling or rounding into guide surfaces, the so-called winding templates, for the wire to be wound. Each of the clamping heads is bearingly supported on a shaft, with the shaft being provided at its end facing the clamping head with a winding arm, each consisting of a wire strap with a guide roller at its free end. During the rotation of the shafts, the guide rollers move on a circular path, thereby winding the wires into the rotor grooves. The switching and alignment of the rotors is effected by means of a pawl engaging the grooves with a nose.

However, the winding apparatus is relatively complicated, in particular because as the winding arms are not adjustable, the introduction of the wire to form the individual coils cannot be controlled and furthermore the apparatus is less suitable for extremely small rotors, as longer stops cannot be avoided in case of extremely short winding cycle times.

Multiple coil winding machines are known for example from U.S. Pat. No. 4,635,865 and Swiss Pat. No. 01786/85-0 for the winding in layers of electrical coils. To be able to wind the great variety of different coil forms in winding machines of this type, the movement of the wire guides and the wire cutting device is displaceable in the X, Y and Z axes, with the wire cutting devices being additionally displaceable relative to the wire guide and also rotatable around their own vertical axis, while being capable of tilting, together with the wire guides. This also assures that the coil wire ends may be applied to all possible connecting elements automatically, exactly and rapidly. The connecting elements may be positioned radially, axially, unilaterally or bilaterally relative to the coil. The coils are wound by rotating the coils set into the winding tool around the axis of the winding tool, while the wire guide merely carries out an advance motion for the clean winding of the individual layers. This makes very high winding velocities possible whereby time losses may be kept very low, even with very short winding cycles.

British Pat. No. 919 652 and German Pat. No. 12 63 159 disclose rotor winding machines wherein the rotor is gripped by a clamping device, whereby the guide surfaces of the guide body make certain that the wire coming from the supply roll is being guided into the grooves to be wound. In the process, the rotor turns with its axis perpendicular to the winding axis, and for the winding of the next layer the anchor is rotated further by a groove division, while the winding tool is stationary. In the British patent, fixation in the prevailing winding position is effected by means of a spring-loaded spherical catch pressing into the gap of a groove. To switch the rotor for the next winding, an angle hook presses against the edge of a groove and rotates the rotor if a key is depressed by one groove division. In these known winding machines the wire is introduced by the aforementioned guide surfaces into the groove, but it is not wound cleanly in layers.

The foregoing illustrates limitations known to exist in present devices. Thus, it is apparent that it would be advantageous to provide an alternative directed to overcoming one or more of the limitations set forth above. Accordingly, a suitable alternative is provided including features more fully disclosed hereinafter.

In one aspect of the present invention, this is accomplished by providing an apparatus for winding rotors of electrical machines including a winding apparatus for small forms with several winding axes, in particular multipolar rotors equipped with collectors with an even or odd number of grooves, whereby winding templates and revolving winding arms are eliminated and the introduction of wires into the grooves to form the coils wound in layers is significantly improved.

A particular advantage of the invention is that the winding tool together with the form holder constitutes a winding unit, so that the winding of the forms with several coil winding axes may be carried out in a manner such that a coil winding axis of the form is always positioned and fixed coaxially with the axis of the winding tool and wound upon the rotation of the winding form by the winding tool, while the wire guide carries out a predetermined displacing motion for the winding of layers. This renders the winding arms and winding templates unnecessary.

The back and forth displacement of the wire guide additionally results in a more uniform coil winding with a higher fill factor than that obtained with a conventional rotor winding using winding arms.

A further advantage is that winding by means of the rotation of the winding tool integrated with the coil form holder, takes place at rpm's that are several times higher than those of conventional winding machines, so that a significant increase in production is assured.

In an advantageous manner, the layouts known from layer winding machines of the wire guides and the wire cutting devices are taken over and combined with the additionally required switching devices, so that the guidance of the wire and the fixation of the coil wire ends, together with the cutting of the coil wire ends in all possible locations, are assured automatically and exactly with minimal time losses, even with extremely short winding cycles.

The foregoing and other aspects will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawing figures. It is to be expressly understood, however, that the drawing figures are not intended as a definition of the invention but are for the purpose of illustration only.

In the drawings:

FIG. 1 illustrates a partial perspective view of an embodiment of a multiple winding machine in the area of the first two winding stations with a winding tool integrated with a coil form holder;

FIG. 2 illustrates a longitudinal section of the winding tool according to FIG. 1;

FIG. 2a illustrates a horizontal projection of the winding tool according to FIG. 2; and

FIG. 3 illustrates a wound three-pole rotor with coil wire ends fastened to connector pins of the collector and relieved of stress.

In FIG. 1, a multiple winding machine illustrated in the area of the first two winding stations 2 is designated 1. For each winding station 2, a wire guide 3, and a wire cutting device 5 are actively connected with a switching device 4. The wire guide 3 and the switching device 4 are located in holders 7 and are connected with a pivot arm 8. The wire cutting device 5 is placed in a holder 6, which is also connected with the pivot arm 8 that may be pivoted 90.degree. around a tilting shaft 9 by means of a pneumatic cylinder. A holding pin 12 is also shown in FIG. 1 and provides a point at which the end of the coil wire may be twisted at the onset of the winding process. To displace the wire guide 3, the switching device 4 and the wire cutting device 5, a slide 10 movable in the X, Y, Z axial directions as indicated in FIG. 1 is provided. The wire cutting device 5 may be additionally displaced parallel relative to the wire guide 3 and the switching device 4 and rotated around its vertical axis. The cooperation of the wire guide 3 with the switching device 4 and the wire cutting device 5 makes the universal processing of the coil wire ends 48, FIG. 3, possible with winding forms of different configurations and several coil winding axes, for example on a three-pole rotor or coil form 40, onto connecting pins 46, FIG. 3, radially or axially mounted on a collector 44. Such a rotor 40 is set for winding in a winding tool 15, in the first winding station 2 of the multiple winding machine 1.

According to FIGS. 2, 2a, each winding tool has a holding shaft 16 with positioning surfaces 17 and a counter nut 18, together with a spacing stop 19. The winding tool 15 may be rotated around a winding axis 20. The outer frontal surface of the winding tool 15 is preceded by a winding form holder 21, which comprises a receiving bore 22 located perpendicularly to the winding tool axis 20, having a switching axis 23, and into which, for example, the three-pole rotor 40 may be inserted with its shaft end 45 located opposite the collector 44. The winding tool body is U-shaped according to FIG. 2 and is open toward the outer frontal surface. The U-shaped body includes a longer U-leg, a relatively shorter U-leg and a connecting web at an end opposite the open outer frontal surface. A spring-loaded slide 30 is located in the U-shaped internal recess and has a fork like configuration on its outer frontal surface, and a positioning catch 24 with a flange 25, together with a guide bolt 27 projecting into a bore 28. The guide bolt 27 is surrounded by a helical compression spring 29 resting against the frontal surface of the bore 28 and pressing the positioning catch 24 against the coil form 40 and securing it with the flange 25. Sliding pieces 31 are connected with the slide 30 and are capable of sliding on both sides on the flat lateral surfaces of the winding tool 15. The positioning catch 24 mounted on the slide 30 may be pushed back by means of the sliding pieces 31 by a resetting device 32 in the form of a sliding piece against the force of the compression spring 29 from the area of the coil form holder 21. In FIG. 2 the wire guide 3 is illustrated in the winding position wherein it is moved in the direction of the arrow Z' along the Z-axis, and in FIG. 2a, a twist-on position 3' whereby the coil wire ends are twisted onto the connecting pins is illustrated additionally by a solid line.

FIG. 3 illustrates a ready wound three-pole rotor 40 with a collector 44, to the connecting pins 46 whereof the coil wire ends 48 are fastened, preferably by twisting. The minimum axial distance between the coil winding axles 49, 49', 49", FIG. 2a, and the connecting pins 48 of the collector 44, is predetermined as a function of the coil form 40 to be wound so that in the course of the winding process, the wire guide 3 has enough space between the connecting pin 46 and the corresponding coil winding axle 49 to carry out the displacing forward movement without interference. Particularly suitable are rotors 40 with a lesser rotor sheet metal pack 41 which has a rotor sheet metal pack length designated by the letter L. The shaft end 45 located opposite the collector 44 may be inserted into the coil form holder 21, FIG. 2. The switching device 4, FIG. 1, preferably with a switching pin, may be guided on frontal casing surface 42 of the rotor sheet metal pack 41 and switches, i.e. turns the rotor 40 around the switching axle 23, FIGS. 2, 2a, from one to the next rotor groove 43, into which the positioning catch 24, FIG. 2a, is then locking in the above-described manner.

Following the completion of the rotor winding, in a subsequent working step the coil wire ends 48 fastened to the connecting pins 46 are soldered and the coil wire ends 48 relieved by depressing the collector 44 mounted on the shaft to the wound coil, into the position indicated by broken lines in FIG. 3.

While this invention has been illustrated and described in accordance with a preferred embodiment, it is recognized that variations and changes may be made therein without departing from the invention as set forth in the claims.