US3047246A - Coil winding machine - Google Patents

Description

July 1962 YOSHINOBU YOJIMA 3,047,246

con WINDING MACHINE Filed Sept. 24, 1959 This invention relates to a coil winder and more particularly to a machine for forming coils or windings directly on transformer cores of wound type.

For many years there has been practiced a machine for winding coils on seamless transformer cores having areas of core windows relatively larger than cross-sectional areas of coils as wound on the same. Such cores may be of toroidal type and mainly used to manufacture repeater coils or autotransformers having variable output voltages and known under trademark Variac.

Also, to form windings on transformer cores of Wound type increasingly used in recent years, there have been proposed various winding systems such as a cut core system, a round coil system, a round core system and a Spina Kore system. The cut core system includes many steps of cutting a core and needs to use the core having cut surfaces thereof in intimate contact with each other. This results in the use of expensive machine tools. Further it has disadvantage that any void between the adjacent cut surfaces of the core will increase electrical loss. In the round coil type, a bobbin rotatably mounted on a leg of a transformer core will be rotated about the leg for forming a winding. Therefore, the leg should be of circular cross section. This leads to increase in the total length of magnetic path of the core and hence to a large sized transformer. This is true in the case of the round core system. The Spina Kore system has disadvantages such as strain of silicon steel strips used, non-uniformity and deterioration in characteristics of the finished products. In brief any of such winding systems is disadvantageous in that the finished products will be not only deteriorated in electrical characteristics but also will be expensive.

One object of the invention is to provide a simple, inexpensive coil winder whereby a coil can be wound directly on a leg of a wound type transformer core with the latter not subjected to any machining operation.

Another object of the invention is to provide a coil winder of the type described in the preceding paragraph, wherein a relatively fine wire can be used.

The principle of the invention is that, at each time a winding is desired to be formed on a transformer of Wound type, a wire winding unit is caused to be formed about the core leg on which the winding will be formed, with the unit extending through the window or windows of the core and with the unit arranged to be rotated about the leg while moved along the same by means of a driving mechanism known per se.

The invention will be more readily apparent from the following description in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of essential parts of a coil winder embodying the invention and illustrating the manner in which a winding is'formed on a transformer core of wound type;

FIGS. 2 and 3 show respectively a plan and a side elevational view of one of elements forming a wire guiding capstan used in the winder of FIG. 1;

FIGS. 4 and 5 show respectively a plan and a side elevational View of the other element forming the capstan;

FIG. 6 shows in radial section one portion of the capstan, and illustrates the manner in which the capstan including a length of wire wound on its periphery en gages one of grooved rollers for supporting the capstan;

Patented July 31, 1962 FIG. 7 is a side view of a tensioning device.

While the invention is applicable to make a winding or windings on a transformer core of each of shell type and core type, it will be described in conjunction with a shell type core.

Referring to FIG. 1 there is shown a transformer core 10 of shell type comprising a pair of Wound type core members 12 substantially identical with each other, with the longer leg of one member juxtaposed in contact with the longer leg of the other core member to form the middle leg 14 of the core. As shown in FIG. 1, the core member 12 is of rectangular cross-section and of rectangular configuration. It is assumed that a length of a relatively fine wire is to be wound on a primary winding already formed on the core leg 14, to form a secondary winding or a high voltage winding with a layer of any suitable insulating material inserted therebetween. The formation of the primary winding will be explained in detail hereinafter.

FIG. 1 also illustrates essential parts of a winding machine embodying the present invention. The core is rigidly mounted in position in the machine by any suitable means with one end thereof substantially contacting a supporting plate 16 secured to a machine frame (not shown). The supporting plate comprises a number of short rods 13 secured thereto and having their free end portions on which grooved supporting rollers 2% are mounted for rotation respectively. The rollers can rotatably support a wire guiding capstan of annular shape generally designated by 22.

As shown in FIGS. 2 and 3, the wire guiding capstan 22 comprises preferably a pair of sernicircularly arcuate members 24 made of any suitable material such as soft steel and capable of being interconnected at their stepped ends as by screws 26 to form a complete annular structure. This construction of the capstan makes it possible to readily assemble and disassemble to same on the rollers 20 as described hereinafter. The member 24 has its outer stepped peripheral portion 28 of the largest diameter which is toothed for the purpose explained hereinafter (FIGS. 2 and 3). -The capstan has a guide ring 30 disposed in the peripheral trough. As shown in FIGS. 4 and 5, the guide ring 3% comprises a pair of semicircular pieces each having an outwardly radial and circumferential extensions at its end and an inner diameter substantially equal to the least diameter of the capstan 22. The semicircular piece may be of any suitable material such as soft steel. One of these semicircular pieces is provided with a radial projection including an aperture, or eye 32 therein for guiding a wire to be wound. The two-piece ring 30 can readily be fitted into the peripheral trough of the capstan 22 by placing the respective semicircular pieces on the trough, abutting against each other and by interconnecting their extensions as by screws. The dimension of the guide ring 30 is selected such that it can slide on the periphery of the capstan freely and smoothly.

The wire guiding capstan 22 can readily be supported on the grooved rollers 20 around the middle leg 14 of the core 10 by inserting each ring member 24 thereof within one of core windows formed of the middle leg,

the outer legs and the yokes of the core, resting on the rollers 20 with its internal periphery fitted into the grooves of the latter, abutting the stepped ends against each other and then interconnecting those ends by the screws 26 to form one piece. Thereafter the guide ring 30 can be mounted to the united capstan 22' as described above. The thickness of the capstan and the width of the groove on the roller are selected that the capstan as supported to the rollers is prevented from moving relative to the rollers lengthwise of the same.

The wire guiding capstan 22 as supported by the 3 grooved rollers 20 is arranged to be meshed at its peripheral toothed portion 28 with a gear 34 secured to a driving shaft 36 connected to a drive (not shown). Thus the drive can rotate the capstan about the core leg 14.

The capstan 22 can readily be removed from the rollers 20 by means of the operation reverse to that described just above.

A wire winding unit generally designated by 40 is provided for winding on the core leg 14 a length of wire as fed from a supply roll (not shown) through the wire guiding capstan 22. The feeding of the wire will be described hereinafter. The winding unit 40 consists of an endless belt 42 adapted to be spanned between and travel on four grooved pulleys 44 disposed substantially in a rectangular arrangement. The endless belt 42 is preferably formed of leather or cotton fabric and includes a small guide piece 46 attached on its outer surface as by rivets and arranged in such a way that the piece has its end portion projecting toward the wire guiding capstan 22 from that edge of the belt facing the same when the belt and the capstan are in their operating positions. Said projecting end portion of said guide piece 46 is provided with an eye 48, through which the wire is passed and wound on the core leg 14. The belt as unused is in the form of an elongated strip having end portions, and this can readily be formed into one endless belt by passing the same around the four pulleys 44 and joining the end portions. By disengaging this joint, the belt can readily be removed from the rollers.

The pulleys 44 are rotatably carried through rods 52 by a U-shaped bracket 54, each arm carrying two rods 52. The upper arm of the bracket 54 has an extension 56 capable of being secured to the same at any desired angle with respect to that arm on the plane of the bracket by means of a bolt 58. The extension 56 is provided at its free end with the rod 52 secured thereto, on which the pulleys 44 is rotatably mounted. Therefore, after the endless belt 42 has engaged the pulleys 44, its tension can readily be adjusted by changing the angle of the extension 56 with respect to the upper arm of the bracket.

The endless belt 42 is adapted to run around the core leg 14 by the rotation of the pulleys 44 and simultaneously to be moved sidewise together with the rollers 42 and bracket 54. Various mechanism for effecting simultaneous rotational and sidewise movements of the endless belt are well known in the art. One form of such mechanisms is shown in FIG. 1, wherein all the pulleys 44, excepting the tensioning guide pulley on the extension 56, are driven by a driving shaft 60 through sprocket wheels 61 to 66 and sprocket chains 67 to 69, whereby the belt runs around the core leg 14. To effect the sidewise translational movement of the belt along the core leg 14, the U-shaped bracket 54 is provided on its base portion with a short, internally threaded sleeve 70 secured thereto and engaging with a feed screw 72 extending therethrough.

The feed screw 72 is rotatably mounted to the machine frame (not shown) and can be selectively coupled to the driving shaft 60 in such a manner that the endless belt 42 will be moved along the core leg 14 by a distance substantially equal to the diameter of the wire to be wound on the leg during one complete rotation of the same. A bar 74 parallel to the feed screw 72 extends through the base portion of the bracket 54 and serves to guide the winding unit 40 along the core leg 14 with the bracket prevented from turning on the feed screw.

It is noted that the driving shaft 60 is coupled to the driving shaft 36 through a transmission device (not shown) in a predetermined relationship as described hereinafter.

It will be understood that the four pulleys 44 be positioned substantially in rectangular arrangement such that two horizontal portions of the belts as well as the two vertical portions thereof as viewed in FIG. 1 are spaced away from each other by a distance more than the maximum diameter of the finished winding formed on the core leg 1-4 with the vertical portions being within the core windows. It will be seen that the spacing between the pulleys can be selected such that the finished winding will occupy a substantial portion of the window area. This is desirable for power transformers.

The operation of the machine described above is as follows:

Assuming that, as described previously the wire guiding capstan 22 is assembled on the grooved rollers in the close proximity to the end of the middle leg 14 Within the core windows of the core 10 mounted to the machine, the winding unit 40 assembled as explained previously is also positioned in the close proximity to the opposite end of the core leg 14 within the core windows. With the capstan 22 and the unit 40 being in such positions, no winding can be formed on that portion of the length of the core leg 14 substantially corresponding to a distance between the end face of the core window and each of the sides of the capstan and the unit remote apart from the respective end face of the core window, so that the dimensions of such components measured along the core leg are preferably as small as possible with the spacing between that end face and the side of the component facing the same also maintained as small as possible.

A relatively fine wire 84 fed from a supply roll (not shown) is passed twice or thrice around the united arcuate members 24 of the capstan 22, threaded through the aperture 32 of the guide ring (see FIG. 6), and thence passed through a tensioning device 78 which will be described later, to the wire guiding eye 48 formed on the endless belt 42. The wire as having passed through the eye 48 has a few turns manually wound on the core leg 14 at a predetermined position adjacent to its opposite end mentioned previously with the end portion of the wire drawn out externally of the core as shown in FIG. 1. Then the winding operation can be started.

In FIG. 7 the tensioning device 78 is shown as comprising three spaced tensioning rollers 80 rotatably mounted to a support plate 82 with their centers lying substantially in a straight line. The support plate 82 may be suitably secured at one end to the guide piece 46 on the endless belt 42 and the wire 84 extend successively around the lower side of the first roller, the upper side of the second and the lower side of the third roller until threads the guide hole 48. This construction of the tensioning device can impart an appropriate tension to the Wire being wound thereby to tightly wind the same on the core leg. The tensioning device also serves to draw continuously the wire being wound nearer toward the guiding hole 48.

The tensioning device 78 may be replaced by a helical spring having one end secured to the guide piece 46 and the other end formed in the form of hook adapted to engage the wire 84.

With the capstan 22, the winding unit 40 and the first portion of the wire 84 disposed as shown in FIG. 1, and with the rotation of the feed screw 72 adjusted to effect the translational movement of the winding unit toward the capstan 22, the driving shaft 60 can be manually or electrically driven to start the winding operation. Assuming that the shaft 60 is rotated counterclockwise as viewed in FIG. 1, the guide rollers 44 also are rotated to move the endless belt 42 on these rollers about the core leg 14 counterclockwise, whereby the wire is wound on the latter. Simultaneously, the feed screw 72 is rotated to move the winding unit 40 toward the guiding capstan 22. As pointed out previously, the endless belt 42 and hence the wire guiding eye 48 is adjusted to be moved along the core leg by a length substantially equal to the diameter of the wire 84 during one complete revolution of the same. Therefore, the resulting turns of the wire are very close to each other.

As the 'wire is Wound on the core leg, the succeeding wire is continuously fed from the supply roll through the wire guiding capstan 22. that the guiding capstan 22 in its operating position should include always a substantially constant length of the wire wound on the periphery thereof. To this end the driving shaft 36 for the capstan 22 is coupled through coupling Qmeans (not shown) to the driving shaft 6% for the winding unit 40 in such a manner that the former shaft will rotate the capstan 2.2 in the direction opposite to the direction of rotation of the endless belt 42 at a rate which the linear speed of the wire as wound on the core leg will be approximately equal to that as leaving the capstan 22 through the wire guiding eye 48 and hence as wound on the capstan. Also, as described previously, the guide ring 80 is arranged to be freely rotated relative to the united ring members 24. This permits the guide ring 3% to be rotated at a rate substantially equal to the speed of rotation of the belt 42 in the direction thereof by virtue of the tension of the travelling wire 84. Therefore, the guide ring 30 is rotated opposite to the united arcuate members 24 thereby to unwind the wire from the capstan 22 at the linear speed mentioned above. This prevents any variation in the tension of the travelling wire and accordingly prevents the same from being broken down due to such variation.

When the leading turn of the Wire reaches a predetermined position on the core leg adjacent to its end at which the Wire guiding capstan 22 is disposed, the rotation of the feed screw 72 is reversed in a manner well known in the art. Then, the winding unit 46 is moved in the reverse direction along the core leg 14 while rotated about the same to form a layer of turns superposed on the first layer of turns. A layer of any suitable insulatingmaterial may be inserted between the first and second layers of turns. In this manner a winding is'formed in any suitable number of turn-layers. 'The winding is completed by fixing the end turn in any conventional manner.

While the invention has been described in conjunction with certain specific embodiments thereof, it is to be understood that various changes and modifications may be made Without departing from the spirit and. scope of the invention.

What I claim is:

1. A winding machine for forming a wire winding on a leg, having oppositely disposed ends, of a wound type transformer core, said machine comprising: roller means mounted around the perimeter of one end of said legs oppositely disposed ends and spaced radially therefrom; a wire guiding capstan for initially engaging said wire to be wound and defining an annulus supported on said rollers for rotation around said one end of said leg, said capstan having a peripheral wire winding surface for engaging several turns of wire to be Wound, and a peripheral trough; a guide ring slidably mounted for free rotation in the same and opposite directions of capstan rotation in said peripheral trough, said guide ring having a wire-guiding aperture through which the wire to be'wound is passed from said peripheral wire winding surface; pulley means mounted around the perimeter of the other end of said legs oppositely disposed ends and spaced radially there from; an endless belt mounted on said pulleys and driven in this connection it is noted around said leg, said belt having a wire guiding perforation through which the wire to be wound is passed from said wire guiding aperture 02": said guide ring, for winding by said endless belt on said leg; means for driving said belt on said pulleys. around said leg and moving said belt and supporting pulleys from said other end toward said one end of said leg at least the thickness of said wire to be wound for every revolution of the wire guiding perforation of said endless belt; and means for rotating said wire guiding capstan opposite to the rotation of said endless belt for winding on said peripheral wire winding surface said wire to be wound, whereby the wire wound on said capstan by the rotation thereof is unwound therefrom by the opposite rotation of said slidably mounted guide ring driven by said endless belt and the tension in the wire therebetween and wound on said leg.

2. A Winding machine as claimed in claim 1, wherein 'a device for tensioning wire is coupled to said endless belt adjacent to said Wire guiding perforation of said belt and comprises three rollers mounted relative to each other to change the direction of linear travel of said wire travelling between said rollers.

3. A winding machine according to claim 1 wherein said wire guiding capstan comprises two semicircular members, and means connecting the ends thereof to form an annulus whereby said capstan can be readily assembled and disassembled around a closed end of a leg core.

4. A winding machine according to claim l'wherein said means for rotating said capstan rotates it at a rate at which the linear speed of the Wire entering and leaving the capstan will be approximately equal to the linear speed of the wire wound on the core leg by the opposite rotation of said endless belt, whereby small variations in said relative linear speeds merely increases and decreases the length of wire in the turns around said peripheral wire winding surface of said capstan thereby avoiding breaking and loosening the wire.

5. A winding machine for forming a winding on a leg of a wound type transformer core having lateral dimensions, said machine including a winding unit, wherein said winding unit comprises an endless belt having a guiding eye for receiving a wire to be wound, said endless belt being disposed on rollers around the core leg so as to conform to each said lateral dimension, means for driving said endless belt around the core leg, means for gradually shifting said belt sidewise, a wire guiding capstan surrounding one end of the core leg and adapted to be rotated at the same speed and in the opposite direction as said endless belt, and a guide ring having a wire guiding eye and loosely mounted on said capstan and adapted to freely rotate in the same direction as the endless belt by virtue of the tension of the wire, whereby wire Wound on said capstan by the rotation thereof and threaded through said guide ring eye to said belt eye is unwound from said capstan and wound on said core by the rotation of said belt.

References Cited in the file of this patent UNITED STATES PATENTS

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