US3102697A - Transformer core winding apparatus - Google Patents

Description

Sept. 3, 1963 M. c. UHRAIN TRANSFORMER CORE WINDING APPARATUS Filed April 2, 1959 4 Sheets-Sheet 1 INVENTOR MICHAEL C. UHRAIN BY j @:.7? ATTOR EY iV- m TRANSFORMER CORE WINDING APPARATUS Filed April 2, 1959 4 Sheets-Sheet 2 O I IO N IO MICHAEL c. UHRMN Sept. 3, 1963 M. c. UHRAIN 3,102,697

TRANSFORMER CORE WINDING APPARATUS Filed April 2, 1959 4 Sheets-Sheet 3 FIG. 5

FIG. 4

L NVE'NTU K MICHAEL c. UHRAIN Sept. 3, 1963 M. c. UHRAIN TRANSFORMER CORE WINDING APPARATUS 4 Sheets-Sheet 4 Filed April 2, 1959 INVENTOR MICHAEL C. UHRAIN WI ATTORN Y United States Patent Ofi Eflhldh? Fatented Sept. 3, 1953 ice Ohio

Filed Apr. 2, 1959, Ser- No. 303,753 2 Claims. (iCl. 242---9) This invention relates to apparatus for winding electrical transformer cores, and more particularly to the winding of single-phase transformer cores of rectangular shape, and to three-phase transformer cores having a pair of adjacent rectangular components which are overwrapped to provide the three legs of the core, each of uniform cross-section throughout an appreciable portion of its length to receive the primary and secondary windings. While the electrical advantages of wound core transformers have been recognized for many years, the practical production of the cores for these transformers has heretofore been rather ditficult hecause no provision has heretofore been made to maintain constant tension in the silicon strip as the same is wound on to the rectangular coil form with the resultant wobbling action of the coil being built up on the form. It is accordingly one of the objects of the present invention to provide an improved method and apparatus for continuously feeding the silicon strip to a core winder embodying a rotating rectangular form while simultaneously and continuously imparting the required back tension in the strip, and also varying the rate of feed of the strip to compensate for variation in the radius of the coil being wound as the coil form rotates.

A further object of the invention is the provision in apparatus of the kind mentioned above of means for accurately and continuously aligning the side edges of the silicon strip being payed onto the coil being wound with the plane of the end surface of the coil portion already completed so that in the finished product the side edges of each convolution of the coil are accurately aligned.

It has heretofore been proposed to construct the core for a three-phase wound-core transformer in the manner indicated in FIGURE 8 of the accompanying drawing wherein a pair of separately Wound rectangular core components A and B are brought into back-to back engaging contact and, while so related, areoverwrapped with silicon strip, as shown at C. There are thus provided in the finished core three legs D, E and F, for receiving the pri mary and secondary coils of the transformer and it will be understood that these legs will he of balanced crosssection if the number of turns in each of the components A, B and C are the same.

Another of the objects of the invention is the provision of an improved method and appaartus for producing the assembly of FIGURE 8 in a rapid, economical manner. Thisis accomplished in my invention by winding the components A and B in adjacent positions and in the same plane and, while these components are yet retained on the winding forms and spindles, they are brought forceably together in back-to-back relation after which laoth are rotated about the common axis to apply the overwrap component C.

A further object of the invention is the provision in core winding apparatus of improved means for controlling the speed of operation of the assembled apparatus, the tension in the silicon strip being wound, and providing for the stoppage of the winding operation while the strip supply remains under tension. The latter feature permits the Wound core or component to he securely bound before the strip supply is severed so that'the finished product is compact and tightly wound as required.

The above and other objects and advantages of the invention will become apparent upon consideration of the following specification and the accompanying drawings wherein there is disclosed certain preferred embodiments of the invention.

In the drawing:

FIGURES l and 2 are side elevation and plan views, respectively, of an assembled hack-tensioning payoff device and core winder constructed in accordance with the principles of the invention;

FIGURE 3 is a horizontal sectional view of the geared drive utilized in the core winder of FIGURES 1 and 2;

FIGURE 4 is a fragmentary vertical section view of the main shaft and a spindle support utilized in the core winder of FIGURES 1 and 2;

FIGURE 5 is the fragmentary vertical section view of a spindle support and position adjusting means therefor utilized in the winder of FIGURES 1 and 2;

FIGURES 6 and 7 are fragmentary vertical section and front elevation views respectively, of a modified form of core winder constructed in accordance with the principles of the present invention; and

FIGURE 8 is a side view of a completely wound core of a three-phase transformer produced in accordance with the principles and by use of the apparatus of the present invention.

Referring now first to FIGURES 1 and 2 of the drawing, this embodiment of the core winder of the invention comprises asulb-base 10 on which is slidably mounted an integral base and gear case 11. As shown in FIGURE 1, the base Ill is anti-cfrictionally mounted on the sub-base it? by means of the rollers 12 and guide rollers 13 whereby the base 11 with all the apparatus carried thereby may be moved outwardly and inwardly as viewed in FIGURE 1. To eifect such movement, and for a purpose to be later described, a double-acting fluid cylinder 14 is carried by the sub-base 10 and is interconnected with the base ll so that upon actuation of the cylinder the base may be moved inwardly or outwardly.

As shown more clearly in FIGURE 3, the base 11 journals a heavy hollow shaft 15 whose forwardly projecting end rigidly mounts a drum 16. in the manner more fully shown in FIGURES 4 and 5,. the drum 16 supports a spaced pair ofdiametrically extending screws 17 which are journaled adjacent their end portions in bearings 18 carried by a structural member 19 of the drum. Extending parallel with the screws 17 and formed as structural members of the drum 16 are ways 2! to slidably receive a pair of blocks 2 lone on either side of the center of the drum. As shown in FIGURE 5, the blocks 21 are provided with locked threaded nuts '22 so that upon rotation of the screws 17 the blocks 21 may be moved toward and away from the axis of rotation of the drum 16. Of course, the opposite end halves of the screws 17 are oppositely threaded so that both blocks 21 move inwardly or outwardly simultaneously and in equal increments. Each of the blocks 21 journals: an outwardly extending spindle 23, and the various parts are so assembled that the axes of rotation of the spindles 23 are always equidistant from the axis of rotation of the drum 16.

To rotate the screws 17 and thus to move the spindles 23 toward or away from each other, as explained above, a worm gear 24- is keyed to each of the screws 17 and these gears are arranged to be driven by a worm 25 which is in turn driven by an air motor 25. To supply air to the motor 26, a double-passaged conduit 27 (FIG- URE 3) extends through the hollow main shaft 15, and a rotary seal 28 of conventional, known design is attached to the rear end of conduit 27 to supply air pressure to either passage, as is well known in the art. To the opposite, or drum end, of the conduit 27 there are attached conduits 29 which are located within the drum and lead to the air motors 26 (normally two such motors are used 3 one at each end of the screws 17). Thus by the use of suitable air supply and valving means, not shown, an operator may cause the spindles 28 to move inwardly or outwardly under remote control, as desired. V

To the rear end of each spindle 23 there is rigidly secured a toothed clutch part 3d, and when the spindles 23 are moved to their outer-most limiting position the spindles and the clutch parts 30 are axially aligned with a pair of drive shafts '31 (see FIGURE 3) journaled in the base 11. As shown, the shafts 31 extend forwardly of the base 11 and to the outer free end of each is rigidly secured a complementary toothed clutch part 32. An internally-toothed sleeve 33 is longitudinally slidable over each pair of clutch parts 30, 32, and when in bridging relation, as shown in FIGURE 3, these sleeves mechanically couple the parts 32 with the parts 3t? so that rotation of the shafts 31 drives the spindles 23. When the sleeves 33 are retracted to overlie only the clutch parts 32 the driving interconnections are broken and the drum and spindles are free to rotate with the main shaft 15. In actual practice a tapered pin, not shown, slidably mounted in a block 34 (FIGURE 2) that is rigidly carried on the base 11 is utilized to enter a tapered aperture, also not shown, in the back wall of the drum 16 to properly index the rotational position of the drum to obtain alignment of the spindles 23 with the drive shafts 31. To actuate this tapered pin inwardly and outwardly under remote control I provide a double-acting fluid cylinder 35.

Referring now particularly to FIGURE 3, it will be observed that a gear 36 is keyed to each of the shafts 31 andinterconnecting the gears 36 is a bull gear 37 which is jonrnaled on the main shaft 15. Driving one of the gears '36 is a pinion 38 which, through a gear reduction 39, is driven by input shaft 40. Shaft 40, in turn, is power-driven through an electromagnetic coupling 41 driven by an electric motor 42.. It will be understood by those familiar with the art that the coupling 41 may be remotely controlled by means, not shown, to predetermine the maximum torque transmitted by shaft 40. In such systems when the torque requirement of the load exceeds this predetermined setting, the shaft 40 will merely stall while continuing to exert the preset torque even though the motor 42 continues to run at rated speed Interconnecting the bull gear 37 and the main driving shaft 15 is a mechanical toothed clutch 43, the movable part 44 of which is arranged to be actuated by a rockshaft 45 which extends outside of the gear case and is normally actuated by a double acting fluid cylinder, not

shown. Of course, when the machine is set up to drive the spindles 23 through shafts 31 the clutch 43 is disengaged so that the bull gear 37 freewheels on the shaft 15. When it is desired to rotate the drum 1-6 the bridging clutch sleeves 33 associated with the spindles 23 are retracted, as explained above, along with the tapered indexing pin mounted in block 34. If the clutch 43 is engaged the drum 16 may now be rotated under controlled power (torque) through a gear train consisting of input shaft 40, gear reduction 39', pinion 38, one of the gears 36, and bull gear 37.

Referring now to the silicon feeding and back-tensioning device used with the winding apparatus above described, and as shown in the left portions of FIGURES 1 and 2, the same is mounted on an unitary base 50. To facilitate threading and observation I prefer to mount all the rolls and passes of this assembly in over-hung relation on the base t. First, I provide a deburring pass to roll down any sharp edges of the strip which may have been caused by prior slitting operations, for example, and this pass includes a hardened lower roll 51 which is mounted for rotation about a fixed axis extending outwardly from the base 50, as shown. A hardened upper roll 52 is journaled in a pair of spaced arms 53 which in turn are welded onto a heavy cantilevered shaft 54 that extends parallel with the axis of rotation of the roll 4 51. To provide a proper controlled working pressure between rolls 51 and 52 a crank arm 55 is rigidly secured to the shaft 54 and is arranged tobe actuated by a fluid cylinder 56.

From the deburring pass 51, 5,2 the silicon stnip passes through a pair of adjustable Side guides 57 and thence over a back-tensioning roll 58 carried by a cantilevered shaft 59. For a purpose to be later described, a holddown roll 60 is journaled in apair of spaced brackets 61 carried by a cantilevered shaft 62. To apply proper pressure between rolls 58 and 60 a crank arm 63 is rigidly secured to the shaft 62 for actuation by a fluid cylinder 64.

shaft 66. To effect maximum wrap of the strip on the roll 65 I provide an idler roll 67 which, as shown in FIGURE 1, is positioned forwardly of the first ten sion roll 58. From the idler roll 67 the strip is wrapped around a light-weight dancer roll 68 carried by the lower end of a flexing leaf spring 69 in such manner as to be normally positioned below theidler roll 67. Leaf spring 69 is in turn carried at its upper end on a cantilever shaft 70 which is controllably biased in a clockwise direction as viewed in FIGURE '1 by a diaphragm-type of air motor 71 acting through a crank arm 72 rigidly secured to shaft 70. The diaphragm motor 7-1, which may be of the kind known commercially as a Rotochamber," is frictionless in operation and if a suflicient volume of air under pressure is connected thereto will provide the same resistance to movement throughout its working range. Thus, during the winding of rectangular coils, Where the larger winding radii are encountered at the corners, the necessary momentary increase in the speed of the strip going into the winder is permitted by the movement of the dancer roll 68 to the right as viewed in FIGURE 1 without any increase in the back-tension of the strip. This is due to the uniform clockwise bias applied to the carrier for roll 68 by the diaphragm air motor 71. A bumperroll 73 limits the clockwise movement of the roll 68.

By relying primarily on the diaphragm air motor 71 to effect the controlled bias on roll 68 the spring 69 'may be made quite stifif to absorb all the momentary shocks which may otherwise be transmitted to the shaft 70. In a representative installation of the apparatus where the air motor'is so used spring 69 was replaced by a tubular arm which appeared to provide sufficient shock absorbing capacity. It is also within the purview of my invention to dispense with the air motor 71 and to rely entirely on the spring action of spring 69 to properly bias the roll 63, which arran-gementshould work satisfactorily if the momentary take-ups in the strip are not severe.

As shown in FIGURE 1, the strip is fed onto the cores being wound over the pair of idler rolls 74, 75 mounted on the winder housing 11 and positioned so that the strip will at all times contact both :of these rolls and thus lie always in the same plane between these rolls. Mounted in this plane is an edge detector 76 which, as is well known to those skilled in the art, operates to produce an air or other signal when the edge of the strip deviates from a predetermined line of travel. This detector is coupled through suitable relay valve means, not shown, to control the actuation of the double-acting cylinder 14 so that the edges of the convolutions being wound may be automatically and accurately aligned. if, for example, the edges cf the convolution being wound begin to drift outwardly from the predetermined desired spacing from the face of drum 16, the error will be detected by the device 76 to move the winder base 11 in a direction which is toward a viewer of FIGURE 1. have the effect of gradually reestablishing the side edge alignment of the convolutions being paid onto the coil. In normal operations the correction required is slight This will because the strip feeding and backatension assembly inheren-tly tends to deliver strip along a constant lateral path.

Back-.tensioning rolls 58 and 6 5 are, of course, keyed on the shafts 59 and 66, respectively, and these shafts are interconnected by suitable gearing shown schematically at 77 while shaft 66 is coupled to the output shaft of a worm reducer 78. The worm shaft 79 of the reducer 78 is double-ended, as shown, and is connected at one end with a small motor it operated through a variable magnetic coupling 81. To the other end of shaft 79 is coupled a suitable speed control device 82 which, in actual practice, may take the form of a positive displacement hydraulic pump in the output conduit of which is located :a speed control valve, not shown. It will be understood that as this valve is progressively tbrottled down the rolls '68 and 75 will turn at less and less speed-low energization and resultant slip in coupling 8 1 permitting thisand in this manner the speed of strip payed off may be controlled. The drive motor 80 is not only useful in overcoming running friction of the parts during normal operation of the apparatus, but is also used for threading. In the latter case it should be observed that upon retracting the pressure rolls 52 and 60, the leading end of the coil of the strip stock may be inserted sideways or longitudinally into the apparatus with the forward end projecting past roll 60. With the motor 8!) energized and coupling 81 at full slip due to lockage at unit '32 and with cylinder 64 energized to bring roll 60 hard down on the strip, the strip may be caused to move forwardly forthreading purposes simply by controllably opening the throttle valve for unit 82. In this manner enough strip may be payed off to be attached to a form, not shown, on one of the spindles 23, and to be entrained over the various rolls as shown in FIGURE 1.

To operate the combined apparatus described above, the strip is threaded and attached to core form as explained immediately above. At this time the pay-off stand is locked by closing the throttle valve for unit 82, for example, and the winder is also locked by ener-gization of a magnetic brake 83 which is on the drive shaft 49 of the winder. With motor 42 energized and brake 83 released, tension will be built up in the strip at the point of winding to an amount determined by the intensity of excitation of the magnetic coupling 42, as will be understood, but the winding will not progress beyond this pick up point because of lockage in unit 82. Sufficient air pressure is furnished motor 71 to retain the dancer roll 68 with the strip entrained thereover in light pressure contact with the bumper roll 7.3. It now the throttle valve for unit 82 is opened, winding of the coil will proceed at a rate of strip travel determined by the setting of the valve. As the winding proceeds, the outer convolution may be continuously ironed out by small follow-rolls 85 which are yieldingly urged toward the axis of rotation of the core being wound by an arm 86 actuated by a fluid cylinder 87. Also during the winding the edges of the core will be maintained straight by operation of the edge detector 76 acting through cylinder 14 as described above. Inasmuch as the magnetic coupling 41 is a constant torque device, the tension in the strip will remain substantially constant regardless of the speed at which the core is wound. Of course, as the core builds up in diameter greater torque will be required to maintain the same strip tension and, in actual practice, this is accomplished by increasing the intensity of energization of the coupling 41 by suitable and conventional control apparatus, not shown.

Upon the core being completed the device 82 is controlled to first decelerate the strip movement and to thereafter bring the rolls 58 and 6 5 to a halt. Since the torque transmitted by the coupling 41 is limited, the winding spindle and core formed thereon will slow up and come to a halt during this interval while yet maintaining the same tension in the strip. After the rotation of the core is stopped the outer convolution of the core may be suitably bound to prevent unraveling after severance of the strip. Prior to such severance the coupling 41 may be totally de-energized to reduce the torque to zero and the brake 83 released to allow the tension in the strip to be relieved before the strip is cut. At this time the drum 16 may be indexed 180 to bring an empty core form adjacent the roll 65 for winding a second core in a manner repetitive of that outlined above. I When winding three-phase cores of the kind suggested in FIGURE '8, the two core components (A and B) may be brought forceably together by first retracting the clutch sleeves 33, aligning vertically the peripheral surfaces of the core components which are to be engaged, and thereafter energizing the air motors .26 to rotate screws 17 (FIGURE 5) to move the core components into pressure engagement with each other. Now the strip is secured to the composite periphery of the core components and the clutch 43 (FIGURE 3) is engaged, whereupon'the entire core assembly and drum is rotated to apply the outer wrapping C. Again, the torque is increased to effect proper tension in the strip by controlling the coupling 41, and the winding operation is started and stopped in the manner described above for a single core.

In the modification of the invention illustrated in FIG- URES 6 and 7, the shaft 15a corresponds generally in structure and function with the shaft 15 in the first de scribed embodiment. Again, shaft 15a carries a drum 16a which corresonds generally in structure and function to the drum 16. There is also provided a pair of blocks 21a which correspond in function but not in structure with the blocks .21 of the first described embodiment. These blocks 21a, instead of being mounted in ways and propelled by screws, are slidably mounted on a pair of guide rods 90 which are carried by and extend directly across the drum 16a equidistantly on opposite sides of the axis of rotation of the drum. As in the case of the blocks 21, each of the blocks 21a rotatably supports a core winding spindle 23.

Each of the blocks 21a has a rack gear portion 21b which faces inwardly toward the axis of the drum 16a to engage a pinion gear 91 which is concentrically disposed on said axis. Gear 91 is carried by a shaft 92 journaled longitudinally in the main hollow shaft 15a and, as shown in FIGURE 6, a worm gear 93 is keyed to the outwardly extending rear end portion of shaft 92. Suitably secured to the rear end face of the shaft 15a is a housing 94 which carries a worm 95 driven by a rotary air motor 96. This motor also carried by housing 94, may be of a kind known commercially as a Gast motor. It is reversible-having a. pair of ports either of which may be selectively employed as an inlet port. For supplying air to these ports I provide a doublepassaged rotary seal 97 which is connected to suitable conduit means 98.

When a single core is being wound on the embodiment of FIGURES 6 and 7, the drum 16a is, of course, held stationery, the clutch 43 is disengaged, as explained above, and air is supplied to motor 96 in such direction as to hold blocks 211:1 outwardly in their proper positions against stops 99 to locate the axes of spindles .23 on the axes of the drive shafts 31 (FIGURE 3). When it is desired to bring the two Wound core components together in making the threeaphase transformer, the difixed outer housing of the rotary seal 97, which is connected to the conduit 98, remains stationery.

It should now be apparent that I have provided imclosed are equally operative for Winding either round,

rectangular, or other shaped cores or core components. The above specifically described embodiment of the invention should be considered as illustrative only, as obviously many changes will be made therein without departing from the spirit or scope of the invention. For example, in the matter of the edge control whereby the successive convolutions being built up on the core are kept aligned I may, instead of moving the base 11 on the winder, mount the base 50 of the back-tensioning pay-off stand in a transversely movable manner for control by device 76 to correct the side shifting of the strip as it enters'the core being wound. Reference therefore should be had to the appended claims in determining the mounted for rotation on said axis, each of said blocks having a rack portion meshing with said gear whereby upon rotation of said gear with respect to said carrier said blocks will be moved equally inwardly toward or outwardly away from each other, a spindle journaled in each said block for rotation about axes parallel with the first mentioned axis, and means to alternately lock said pinion gear with respect to said carrier and to rotate said pinion gear with respect to said carrier;

2. Apparatus according to claim 1 further including a hollow shaft journaled for rotation on said first mentioned axis for driving said carrier, and inner second shaft extending longitudinally in said hollow shaft and journ aled therein, said pinion gear being carried by an extending end of said second shaft, and means carried by the opposite end of said hollow shaft to lock second shaft against rotation with respect to said hollow shaft or alternately to rotate said second shaft relative to said hollow shaft.

References Cited in the file of this patent UNITED STATES PATENTS 2,006,628 Cline July 2, 1935 2,108,664 Franze Feb. 15, 1938 2,281,965 Wylie May 5, 1942 2,295,327 Bendz Sept. 8, 1942 2,401,676 Weber June 4, 1946 2,590,665 Williams Mar. 25, 1952 2,655,717 Dunn Oct. 20; 1953 2,660,380 Blackman et al Nov. 24, 1953 2,726,819 Zander et a1. Dec. 13, 1955 2,735,630 Ziebolz Feb. 21, 1956 Hill May 12, 1959

Claims (1)

1. APPARATUS FOR WINDING A CORE OF A THREE-PHASE TRANSFORMER COMPRISING IN COMBINATION A POWER-DRIVEN ROTATABLE CARRIER, A PAIR OF BLOCKS MOUNTED ON SAID CARRIER ON OPPOSITE SIDES OF THE AXIS OF ROTATION THEREOF, GUIDE MEANS ON SAID CARRIER FOR GUIDING THE MOVEMENT OF SAID BLOCKS TOWARD AND AWAY FROM SAID AXIS, A PINION GEAR MOUNTED FOR ROTATION ON SAID AXIS, EACH OF SAID BLOCKS HAVING A RACK PORTION MESHING WITH SAID GEAR WHEREBY UPON ROTATION OF SAID GEAR WITH RESPECT TO SAID CARRIER SAID BLOCKS WILL BE MOVED EQUALLY INWARDLY TOWARD OR OUTWARDLY AWAY FROM EACH OTHER, A SPINDLE JOURNALED IN EACH SAID BLOCK FOR ROTATION ABOUT AXES PARALLEL WITH THE FIRST MENTIONED AXIS, AND MEANS TO ALTERNATELY LOCK SAID PINION GEAR WITH RESPECT TO SAID CARRIER AND TO ROTATE SAID PINION GEAR WITH RESPECT TO SAID CARRIER.

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