Deflection coil and fabrication method thereof

Abstract: This invention relates to a deflection coil of a saddle type and a fabrication method thereof. The method has the step of winding in layers multi-layered wire ribbons into coil-winding grooves of wire-winding frame die of a saddle shape while the multi-layered wire ribbons in which wire ribbons are piled in two or more layers are delivered out from one nozzle. The deflection coil has a coil formed into a saddle shape by layer-winding multi-layered wire ribbons that are piled in two or more layers. Layers of the multi-layers ribbon may be so marked as to be easily discriminated.

Description: 1. Field of the Invention The present invention relates to a fabrication method of a deflection coil of a deflection yoke mounted on television receivers or display units, and a deflection coil fabricated by this method. 2. Description of the Prior Art In recent years, development of television receivers into those of high-vision and appearance of high fine display units, increasingly tend to demand strict specifications relating to color mismatching, i.e., convergence of the cathode-ray tube screen of these apparatus. Under such tendency, it is earnestly desired that a deflection magnetic field be controlled more precisely. Fig. 1 shows an example of a bobbin for a saddle type deflection coil for use in a typical deflection yoke. The bobbin 2 is provided with a plurality of coil-winding grooves 5, on which, for example, a coiling wire 11 is wound in layers as shown in Fig. 2, to thereby form a deflection coil. The coiling wire 11 comprises conductive wires (including litz wires) with an insulating layer 4 provided thereon which is coated with an adhesive on its peripheral. In winding the coiling wire 11 on the aforementioned coil-winding grooves 5, the coiling wire 11 is wound in layers by an automatic winding machine, one by one, or a few at a time, whereby a deflection coil will be produced. Subsequently, the thus layer-wound coil is supplied with an electric power, to heat and melt the adhesive applied outside the insulating layer 4, so that the coil wires adhere to each other to complete a deflection coil. Such prior art deflection coil, however, suffers from difficulties: owing to variation of the stretching force actingon coiling wire 11 as it is wound and other reasons, the coiling wire 11 is displaced and biassed as shown in Fig. 2, and in other cases, the order of winding of coiling wire 11 is altered and hence such winding as previously designated by a design instruction cannot be practiced. Further, the biassed states of coiling wire 11 of a deflection coil that is mass-produced differ from one to another for each article, therefore, it would be impossible to regulate a deflection field with high precision. Additionally, mass-production makes dispersion of products larger, resulting in lowering of the yield, and hence the prior art winding method is disadvantageous in view of the cost. Even in the just-mentioned prior art method, the coiling wire 11 is reduced in its displacement and biassed winding as the width of the coil-winding groove is narrowed to satisfy an original design, but followed by another problem of coil performance being deteriorated because of a ratio L/R between inductance L and resistance R being reduced. In order to eliminate such problems, the present applicant has previously proposed a deflection coil which is composed by forming a conductive wire row member (which will be referred to as "wire ribbon" hereinafter) in which a plurality of adjoining conductive wires are arranged parallel in a row, and winding this member in place of winding a single wire one by one as used to be practiced. Examples of such a wire ribbon 15 include one that is composed as shown in Fig. 3A by arranging in parallel a plurality of conductive wires 8 of copper, aluminum or the like with an insulating layer 4 coated thereon, and adhering them using an adhesive 6; one that is composed as shown in Fig. 3B by arranging in parallel a plurality of conductive wires 8 with an insulating layer 4 coated thereon, and adhering together the wires on one side of an insulator sheet 7 of resin, etc., with an adhesive 6; one that is composed as shown in Fig. 3C by arranging and adhering together in parallel a plurality of conductive wires 8 formed with an insulating layer 4 and an adhesive layer 9; and one that is composed as shown in Fig. 3D by arranging a plurality of conductive wires in a contacting manner in a row, each wire being with an insulating layer 4 covered by a thermoplastic adhesive layer 20. The conductive wires 8 forming the aforementioned wire ribbon 15 are arranged in parallel with one another in an orderly manner in a row, and therefore, neither will each conductive wire 8 be displaced in wire ribbon 15, nor will the order of the wires be altered. Therefore, when this wire ribbon 15 is delivered out from a nozzle of an automatic winding machine (not shown), the wire ribbon 15 is inserted into a coil-winding groove 5 having a flange 3 so as to be wound in layers as shown by way of example in Fig. 4. By this method, it is possible to produce a deflection coil free from the problems such as significant displacement of the conductive wires 8, and the like. The deflection coil formed with the wire ribbon 15 can be remarkably improved in its characteristics as compared with those in the prior art. A deflection coil formed with a bandcable is disclosed in DE-B-2 744 048. Another type of deflection coil is disclosed in GB-A-1 311 482, whereby superimposed insulated foils are used as winding. However, in a case where a deflection coil is produced using a wire ribbon 15 of the prior art, a single layered wire ribbon is used to form the coil, therefore the winding operation has to be repeated many times in order to complete the coil. That is, this operation takes a lot of time, so that the working efficiency for coiling is low. On the other hand, when a horizontal deflection coil having a low impedance is to be made, it is necessary to use a conductive wire 8 having a large diameter (for example, 0.7 mm in diameter). In winding in layers a wire ribbon 15 formed with the thick conductive wire 8 through a nozzle of the automatic winding machine into coil-winding groove 5, the wire ribbon cannot fit in with the shape of a winding frame die due to thickness of the wires, unless a strong tension force is used when the member is wound. Even with the strong tension, the winding operation is hard to perform, and to make matters worse, the nozzle and the bobbin of the winding machine as well as wire ribbon 15 itself receive stress. The stress causes insulating layer 4 of the wires to peel off, and may, in some cases, cause the wires to become disconnected. Besides, there is a fear that the nozzle might be worn , the bobbin might be deformed, or other defects may occur. The deformation of the bobbin may disadvantageously produce a deflection coil with an improper shape. In addition, depending upon the structure of the wire winding machine and/or the strength of insulating layer 4 of conductive wires 8, an excessively strong tension can not be used to wind wire ribbon 15. In such a case, wire ribbon 15 would not bend properly at the edges of the winding frame die, resulting in failure to form an exactly shaped coil. Further, when thick wires are wound, if a predetermined number of conductive wires are inserted in a predetermined width, the loss due to proximity effect will increase with the thickness of the wire. Additionally, the loss of alternating current due to skin effect will increase with increasing wire thickness, making it impossible to cope with alternating current with high frequencies. SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing circumstances, and has for its object to provide a deflection coil and a fabrication method thereof wherein electric conductive wires are prevented from being displaced and being disturbed in their order by using conductive wire row members (or wire ribbons) for coil conductive wires forming the deflection coil, and wherein abrasion of a nozzle, deformation of a bobbin and peeling-off of the insulating layer can be prevented, and excellent dimensional precision of the coil can be achieved with an easy winding operation. In order to achieve the above object, according to a first aspect of the present invention, there is provided a fabrication method of a deflection coil of saddle type, characterised by: preparing a multilayer of conductive wire row members wherein said members comprise a plurality of conductive wires, covered with an insulating layer, arranged close to one another in a row and joined to one another with adhesive, and winding in layers said multilayer into coil winding grooves of a saddle shaped wire winding frame die wherein said multilayer is delivered from a nozzle and the conductive wire row members are individually subjected to adjustment of tension. According to a second aspect of the present invention, there is provided a deflection coil of saddle type fabricated by the said method and characterised by a plurality of layer wound multilayers of conductive wire row members wherein said members comprise a plurality of conductive wires covered with an insulating layer, arranged close to one another in a row and joined to one another with adhesive. In a deflection coil in accordance with the above second aspect, the multi-layered conductive wire row members may have different discriminating display means for each layer so as to be discriminated one layer from another. Further, in a deflection coil in accordance with the above second aspect, the multi-layered conductive wire row members are piled in three layers or more, and the intermediate conductive wire row member or members sandwiched between the lowermost and uppermost layers have an insulation breakdown voltage lower than those of said uppermost and lowermost conductive wire row members. As has been apparent from the foregoing description, in accordance with the present invention, since a saddle type deflection coil is formed by winding in layers wire ribbons, neither will each conductive wire be displaced in wire ribbons, nor will the order of the wires be altered. In addition, since the wire ribbons piled in two or more layers are layer-wound, a thin type single-layered wire ribbon can be formed by dividing the conventional thick type single-layered wire ribbon, and extremely thin conductive wires can be used as compared with those of the conventional example. For this reason, it is possible to easily wind up the wire ribbons with a weak tension. Moreover, even with the weak tension, the wire ribbons can be wound in layers in a desired manner following the curves or edges of the bobbin or metal die to form a deflection coil having a proper dimension. Accordingly, as there is no need to use a strong tension, there is no fear that the tension would deform the bobbin, cause abrasion of the nozzle, or peeling off of the insulating layer, and it is possible to produce a deflection coil having a proper dimension and shape. In this manner, it is possible for the thus produced saddle type deflection coil to effect a precise control of a deflection magnetic field. Further, with regard to the structure in which the piled wire ribbons are colored separately to discriminate one from another, this makes it easier to control the order of wires and twist of layered ribbons by visual observation. Moreover, with regard to the structure in which the intermediate wire ribbon or ribbons sandwiched between the lowermost and uppermost layers are provided with an insulation breakdown voltage lower than those of the uppermost and lower most wire ribbons when a deflection is formed by winding in layers three or more piled wire ribbons, the intermediate layer can be made with a wire ribbon of low insulation-breakdown voltage, which is low in cost, so that it is possible to reduce the cost of the deflection coil itself. Still, since it is possible to use wire ribbons having a small thickness which are formed by dividing the conventional single-layered wire ribbon having a large thickness into a plurality of layers, it becomes possible to use thin wires as compared with the conventional example. As a result, proximity effect can be improved. In addition, since no potential difference occurs between piled wire ribbons, the distributed capacity is not increased, so that it is possible to remarkably improve the deflection coil in its electric characteristics. The above and many other advantages, features and additional objects of the present invention will become manifest to those versed in the art upon making reference to the following detailed description and accompanying drawings in which preferred structural embodiments incorporating the principles of the present invention are shown by way of illustrative example. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic perspective view showing an example of a bobbin used in a conventional deflection coil; Fig. 2 is an illustration partially showing coil-windings on a bobbin of a conventional deflection coil; Figs. 3A to 3D are schematic perspective or sectional views showing different types of single layered conventional wire ribbons; Fig. 4 is an illustration of a deflection coil formed by winding in layers a conventional single layered wire ribbon; Fig. 5 is a schematic view showing a multi-layered wire ribbon for producing a deflection coil in accordance with the present invention; Figs. 6A and 6B are, respectively, top and side views showing a wire winding machine for producing a deflection coil of the present invention; Fig. 7 is an illustration showing a state in which wire ribbon is wound in layers onto a bobbin when a saddle type deflection coil of the present invention is produced; Fig. 8 is a front view showing a saddle type deflection coil of the invention separated from a coiling frame die; Fig. 9 is a sectional view showing a layered structure of a three-layered wire ribbon; and Figs. 10A and 10B are schematic perspective views showing different discriminating means of multi-layered wire ribbons for use in a deflection coil of the invention. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Embodiments of the invention will hereinafter be described with reference to the accompanying drawings Figs. 5 to 9B. In the description of the embodiments of the invention, like reference numerals will be allotted for the same parts with those in the aforementioned conventional example, and the detailed description for these parts will be omitted to avoid the repetition. Fig. 5 is a perspective illustration showing a wire ribbon for a saddle type deflection coil in accordance with an embodiment of the present invention. Characteristic feature of this embodiment lies in that wire ribbons piled in two or more layers (three layers in this embodiment), each ribbon being made up of thin wires, are delivered together in a piled state from one nozzle, to be wound in layers in coil-wiring grooves of a bobbin or a coiling frame die of saddle shape so as to form a saddle shaped deflection coil. In Fig. 5, each layer 15A, 15B or 15C of multi-layered wire ribbons has twelve conductive wires 8 covered with an insulating layer 4 arranged close to one another in a row and adhered together with an adhesive. In this embodiment, a thin type single-layered wire ribbon one-third as thin as the conventional thick type single-layered wire ribbon is used, and thin conductive wires can be used with broader intervals therebetween as compared with those of the conventional example. For convenience to discriminate three-layered wire ribbons 15A, 15B and 15C, one from another, discriminating displays are allotted for each (red, black and green are allotted respectively in the embodiment). Each of the aforementioned adhesives is dyed for the color separation. For example, wire ribbons 15A, 15B and 15C are colored in red, black and green, respectively. Figs. 6A and 6B respectively show schematic top and side views of a wire winding machine for making a deflection coil of the embodiment. The wire winding machine comprises three reels 25A, 25B and 25C (25B and 25C are not shown) having wire ribbons 15A, 15B and 15C on their own, respectively; a reel rotating mechanism 12; reel holding member 31; and tension adding means 16A, 16B and 16C (16B and 16C are not shown). The aforementioned three wire ribbons 15A, 15B and 15C are delivered from reels 25A, 25B and 25C, respectively, and tension-adjusted individually, by tension adding means 16A, 16B and 16C, and piled to be lead to a nozzle slot of a nozzle shaft 27. Nozzle shaft 27 is supported by a nozzle supporting table 26, which in turn is provided with a nozzle rotating mechanism 28. Nozzle rotating mechanism 28 allows nozzle shaft 27 to be rotatable in clockwise or anti-clockwise direction as required. The nozzle supporting table 26 is attached shiftable in a vertical direction (a direction denoted by Y) along a nozzle supporting column 35, which is planted shiftable in X direction (horizontal direction) by means of a driving mechanism such as screw, etc., of a nozzle head 23 fixed on a machine base. The aforementioned nozzle shaft 27 has a nozzle (not shown) attached in its lower side, and the above-mentioned wire ribbon 15A, 15B and 15C are delivered out being piled from the nozzle, so as to be inserted into a coil-winding groove of saddle-shaped coil frame die or bobbin 43. The coil frame die or bobbin 43 is mounted on a supporting table 41, which in turn is supported by a die-side column 37 through an arm 40. The die-side column 37 has a first die-rotating mechanism 38 at its upper side. A coil frame die holding portion 42 is provided for a supporting table 41 of coil frame die or bobbin 43, and is shiftable in Z-direction (a direction normal to the paper surface in Fig.6B). This coil frame die holding member 42 is provided with a second die rotating mechanism 44. The aforementioned coil frame die or bobbin 43 is rotatable about X-axis following to the rotation of first die rotating mechanism 38, and is rotatable about the Z-axis by the driving force of the second die rotating mechanism 44. Reel rotating mechanism 12 is linked with nozzle rotating mechanism 28 and therefore performs the same rotation in synchronization with the mechanism 28 so that wire ribbons 15A, 15B and 15C, delivered from reels 25A, 25B and 25C by the rotation of the nozzle, will not be twisted. All the rotation driving mechanisms described above are regulated by an unillustrated controller, so that wire ribbons are wound up in layers smoothly into the coil-winding groove of coil frame die or bobbin to form a deflection coil. Now, a fabrication procedure of the saddle type deflection coil of the embodiment will be described. First, wire ribbons 15A, 15B and 15C wound around respective reels 25A, 25B and 25C as shown in Fig. 6B being tension-adjusted individually by tension adding means 16A, 16B and 16C, are passed being piled into one nozzle slot (not shown) of nozzle shaft 27. The thus piled wire ribbons 15A, 15B and 15C are delivered out from the nozzle and inserted into the coil-winding groove of the saddle shaped bobbin or coil frame die to be wound in layers therebn while being controlled by an unillustrated controller. Thus, a coil having a saddle shape is formed. After the formation of the coil, wire ribbons 15A, 15B and 15C are subjected to a terminal treatment to be connected to one another in parallel. Here, in a case where the wire ribbons 15A, 15B and 15C are coiled in layers onto bobbin 2, after the formation of the coil, the thus wound wire ribbons 15A, 15B and 15C are developed into an integrated structure through heating by supplying electric power to fuse and solidify the coil or by injecting a filler type resin into the layered coil, to thereby form a saddle type deflection coil as shown in Fig. 7. On the other hand, when wire ribbons 15A, 15B and 15C are wound in layers around a wire-winding metal die to form a coil, after the formation of the coil, the thus wound wire ribbons 15A, 15B and 15C are developed into an integrated structure by fusing the layered coil together, or by injecting a filler type resin into the layered coil. After the treatment, the integrated layered coil is separated from the metal die to complete a saddle shaped deflection coil as shown in Fig. 8. According to this embodiment, since the wire ribbons are wound up in layers to form a saddle type deflection coil, neither will each of single conductive wires be displaced in a wire ribbon, nor will the order of the wires be altered. Further, the wire ribbons using thin conductive wires are tension-adjusted one by one individually, and are piled in three layers to be wound up in layers, therefore, it is possible to wind in layers the three layered wire ribbons by applying only weak tension thereto, and even with the weak tension, the wire ribbons can be wound in layers following the curves or edges of the bobbin or coil frame die, to form a deflection coil having a proper dimension and shape. Accordingly, as there is no need to use a strong tension, no fear occurs that the tension would deform the bobbin or cause wear of the nozzle, and,since no stress is imposed on insulating layer 4, no mechanical deterioration such as peeling off of insulating layer 4 occurs either. In this manner, it is possible for the thus produced saddle type deflection coil to perform a precise control of a deflection magnetic field. Further, since the three layered wire ribbons are colored separately to discriminate one from another, this makes it easier to control the order and twist of layered ribbons by visual observation. Moreover, since deformation of the bobbin and abrasion of the nozzle can be eliminated, the cost for maintenance can be diminished. Still, since the three layered wire ribbons 15A, 15B and 15C are connected to one another in parallel after the layer-winding of the ribbons, the piled coil layers made of three layered wire ribbons 15A, 15B and 15C become equi-potential. However, a second coil layer 33 will not be equal in potential with a previously wound first coil layer 32 or a subsequently wound third coil layer 34, therefore, the wire ribbon 15A of the previously wound first coil layer and the wire ribbon 15C of the subsequently wound third coil layer all of which are adjacent to the coil layer 33, are required to be made with a wire having a high insulation-breakdown voltage. The intermediate layer, i.e., wire ribbon 15B, is equi-potential with the ribbons 15A and 15C, and does not come in direct contact with the first and third coil layers 32 and 34, so that it is possible to set a low insulation-breakdown voltage. Accordingly, the intermediate layer can be made with a wire ribbon of low insulation-breakdown voltage, which is low in cost, so that it is to possible to reduce the cost of the deflection coil to be made. Further, since wire ribbons 15 made of thin conductive wires 8 of single-wire lines arranged close to each other in a row are wound in layers, the wire ribbons are easy to be fit in with the shape of wire-winding frame and therefore easy to wind and the loss due to proximity effect can be improved, and the loss of alternating current may be prevented from increasing. Moreover, since the three layered wire ribbons are subjected to the terminal treatment to be connected in parallel, the three layered wire ribbons are equi-potential and therefore distributed capacity does not increase, so that it is possible to remarkably improve the deflection coil in its electric characteristics. It should be noted that the present invention is not limited to the above embodiment, but various practical configurations can be adopted. For example, although in the above embodiment wire ribbon 15A, 15B and 15C are colored respectively by dyeing the whole of the adhesive layer of conductive wires 8 as the discriminating display means of the wire ribbons, wire ribbon 15A, 15B and 15C may be provided with different colored longitudinal lines (A, B, C) as shown in Fig. 10A or with different colored transverse lines (D, E, F) as shown in Fig. 10B, and other display means may work as long as it allows easy discrimination by visual observation. If color separation is effected in the width direction, it is possible to observe and judge the twist and the order of the wires in the width direction, and it is also possible to separate the wires in the width direction to allow series connection. In the above embodiment, although three layered wire ribbons are connected together in parallel after completion of layer-winding process, series connection can be made instead. In this case, if three layered wire ribbons are employed, a deflection coil can be created by winding in one-third the number of times for the winding as when a single layer wire ribbon is wound in layers to form the same deflection coil. Generally, if n-times layered wire ribbons are used, it is possible to create the deflection coil by winding one nth the number of times for making the same deflection coilas in the prior art method. Accordingly, it is possible to perform the winding process in a very short time. This case, however, requires the intermediate layer of wire ribbon 15B to be provided with the same insulation-breakdown voltage with those of the uppermost and lowermost layers, or, wire ribbons 15A and 15C. Further, in the above embodiment, as wire ribbons are piled in three layers and the thus piled wire ribbons are wound in a plurality of layers to form a deflection coil, wire ribbons may be piled in two or four, or more layers, no matter how many they are. Moreover, in the above embodiment, although a single wire line is used for conductive wire 8 of wire ribbon 15, a litz wire can be used for conductive wire 8. Nevertheless, the single wire is less expensive, so that this may present advantage in cost.

Claims: A fabrication method of a deflection coil of saddle type, characterised by: preparing a multilayer of conductive wire row members (15) wherein said members (15) comprise a plurality of conductive wires (8), covered with an insulating layer (4), arranged close to one another in a row and joined to one another with adhesive (6); and winding in layers said multilayer into coil winding grooves (5) of a saddle shaped wire winding frame die (43) wherein said multilayer is delivered from a nozzle and the conductive wire row members (15) are individually subjected to adjustment of tension. A deflection coil of the saddle type fabricated by the method of Claim 1 and characterised by a plurality of layer wound multilayers of conductive wire row members (15) wherein said members (15) comprise a plurality of conductive wires (8) covered with an insulating layer (4), arranged close to one another in a row and joined to one another with adhesive (6) . A deflection coil according to claim 2, wherein the multilayered conductive thin wire row members (15) have different discriminating display means for each layer so as to distinguish one layer from another. A deflection coil according to claim 3, wherein the multilayer of conductive wire row members (15) consists of at least three layers, and the intermediate conductive wire row member or members (15) sandwiched between the uppermost and lowermost layers have an insulation breakdown voltage lower than those of said uppermost and lowermost conductive wire row members (15).

Inventors: IKEUCHI HIROSHI, IKEUCHI, HIROSHI, Ikeuchi, Hiroshi, c/o Murata Mfg. Co., Ltd.
Applicants: MURATA MANUFACTURING CO, MURATA MANUFACTURING CO., LTD.
Application year: 1993
Main classification: H01J9
IPC codes: H01F5, H01F41, H01J9, H01J29