JP2005158857A - Mold coil - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coil structure having an improved heat dissipation property, and to provide a mold coil which is strengthened against electromagnetic mechanical force which works at the time of shorting. <P>SOLUTION: The resin mold coil comprises a coil 1 formed by winding a conductor and an insulation layer 2 which is formed on the inner and outer peripheries of the coil 1. The coil 1 is formed by stacking, in the axial direction, a coil which is such that an element wire is wound several times from the outer to inner periphery in the radial direction and a coil which is such that the element wire is wound several times from the inner to outer periphery. The circumference of the coil 1 is coated with the resin 2 to obtain insulation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a molded coil, and more particularly to a resin molded coil used for a stationary induction device such as a transformer.

  Molded coils made by molding conductor windings with epoxy have many advantages in terms of disaster prevention, such as excellent mechanical strength, insulation performance, moisture resistance, and flame resistance. Yes. Recently, a molded transformer using the molded coil is required to be smaller and less expensive. In order to meet this requirement, a structure with better heat dissipation characteristics is indispensable.

  A conventional winding structure of a molded coil is roughly divided into the following structures. For example, as described in Patent Document 1, a round wire or a square wire is wound in a cylindrical shape in the axial direction, an insulating material is wound around the outer periphery, and a winding conductor is wound thereon. . This is repeated a predetermined number of times to form a winding unit, and a coil winding is formed by connecting this winding unit in the required number of axial directions in series.

The other is, for example, as described in Patent Document 2, by winding a strip-shaped conductor into a cylindrical shape with an insulating material interposed therebetween to form a winding unit, and arranging and connecting the necessary number of pieces in the axial direction. Thus, a coil winding is formed.
JP 63-72106 A JP 54-104529 A

  According to said method, it is necessary to wind an insulating material between the layers of a coil, and automatic winding is difficult. Further, when the insulating material is inserted between the winding layers, there is a risk that stress is concentrated due to a difference in linear expansion between the casting resin and the interlayer insulating material and a notch effect at the end thereof, and cracks are generated.

  For this reason, it is desirable that there is no interlayer paper. Further, Joule heat generated in the coil is finally radiated from the outer surface of the coil, that is, the inner and outer peripheral surfaces and the axial end. Since a normal mold coil has a cylindrical shape that is long in the axial direction, a large amount of heat is released outside the coil from the inner and outer peripheral surfaces that have a much larger area than the axial end. For this reason, the heat generated inside the coil is mainly transmitted in the radial direction. However, in the conventional coil structure as described above, since many insulators having low heat conduction are arranged so as to divide the radial direction, heat transfer in the radial direction is prevented. As a result, the coil has a large temperature difference between the inside of the coil and the coil surface, and has poor heat dissipation characteristics.

  In addition, when a short circuit accident occurs on the secondary side of the transformer, a large current that is several to several tens of times the normal amount flows. The short circuit current causes an excessive electromagnetic mechanical force to act on the transformer winding. The mechanical force is repulsive between the primary side coil and the secondary side coil, and the force is relatively evenly distributed in the cylindrical coil. Since a large concentrated load is applied to the straight line portion, the short-circuit strength is weak, the coil is deformed, the impedance change rate is large, and the problem that it is impossible to continue use in a single short-circuit accident cannot be solved. It remained.

  In order to solve the above-described problems, the present invention proposes a coil structure with enhanced heat dissipation and a molded coil that is reinforced against the electromagnetic mechanical force that works during a short circuit.

  The present invention has been made in order to achieve the above object. As a first aspect of the present invention, when a winding coil is wound in a spiral shape from the inner periphery to the outer periphery of the coil and wound to the outermost periphery. Winding from the outer periphery to the inner periphery and stacking. By repeating this, a coil is formed. According to this method, the voltage difference between adjacent conductors becomes small, and the conventionally required interlayer paper can be abolished. Cost can be reduced and the risk of cracking is reduced. it can. Moreover, since this was an impediment to radiating the Joule heat generated inside the coil, the heat dissipation is improved and the coil can be made compact.

  Furthermore, if the cross-sectional shape of the electric wire is a rectangular wire, the conductor occupancy of the coil is improved, and the coil can be made more compact.

  When the shape of the coil is rectangular, by making the bending direction of the flat wire edgewise, it is possible to improve the strength against the electromagnetic mechanical force that works at the time of short circuit, and improve the quality of the transformer.

  Moreover, after winding by edgewise using a machine, a tap drawer | drawing-out part can be provided and it can wind by flatwise next by manual winding.

  ADVANTAGE OF THE INVENTION According to this invention, the mold coil which is excellent in heat dissipation, an insulation characteristic, and workability | operativity at the time of manufacture, and is small and strong to the electromagnetic mechanical force at the time of a short circuit is provided.

The best mode for carrying out the present invention will be described.
Examples of the molded coil of the present invention will be described below with reference to the drawings. 1 is a coil cross-sectional view of a molded coil of Example 1. FIG. FIG. 2 is a coil perspective view of the molded coil according to the first embodiment. FIG. 3 is a perspective view of the coil after the completion of the tap wire forming in the first embodiment. FIG. 4 is an explanatory diagram of an example of a coil forming unit of the molded coil according to the first embodiment. FIG. 5 is an explanatory diagram of a second example of the coil forming unit of the molded coil according to the first embodiment. FIG. 6 is an explanatory diagram of a third example of the coil forming unit of the molded coil according to the first embodiment. FIG. 7 is an explanatory diagram of a fourth example of the coil forming unit of the molded coil according to the first embodiment. FIG. 8 is an explanatory diagram of a fifth example of the coil forming unit of the molded coil according to the first embodiment. FIG. 9 is an explanatory diagram of a sixth example of the coil forming unit of the molded coil according to the first embodiment. FIG. 10 is a coil cross-sectional view of the molded coil of the first embodiment. FIG. 11 is a coil cross-sectional view of the molded coil of the first embodiment. FIG. 12 is an explanatory diagram of an example of a coil casting unit in the molded coil of the second embodiment. FIG. 13 is an explanatory diagram of another example of a means for casting a molded coil according to the second embodiment. FIG. 14 is a coil cross-sectional view of the molded coil of the second embodiment. FIG. 15 is a coil perspective view of the molded coil according to the third embodiment. FIG. 16 is a cut coil perspective view of the molded coil of Example 3. FIG. FIG. 17 is an explanatory diagram of a molded transformer assembled using the molded coil of the first embodiment.

  Example 1 is a mold coil configured by laminating a winding unit obtained by winding a rectangular wire conductor in the coil radial direction in the axial direction. FIG. 1 schematically shows the winding method of the rectangular wire conductor 3 in the resin molded coil of the present embodiment from the radial direction of the molded coil. Winding is started from the end of the coil, wound from the outer periphery toward the inner periphery, raised to the upper stage, and then wound from the inner periphery toward the outer periphery. By repeating this up to the specified number of turns, the coil 1 is formed and the periphery thereof is covered with the resin layer 2. A perspective view of FIG. 1 is shown in FIG. FIG. 3 shows the coil with the tap wire pulled out.

  The resin-molded coil according to the present embodiment is formed by forming the rectangular wire 3 and bending it edgewise. In particular, rectangular coils divide a rectangular wire into a straight portion and a bent portion and perform different forming methods.

  Next, an example of the method for manufacturing the molded coil of the present embodiment will be specifically described. First, conductor bending will be described. Hereinafter, a method for bending a flat wire edgewise will be described. 4 (a) and 4 (b), a rectangular wire is passed between the rollers 5 installed at the top and bottom, and the angle of the roller 5 is automatically changed arbitrarily so that the wire is rounded. According to this method, a rectangular wire can be formed at an arbitrary R, and both a round coil and a rectangular coil can be manufactured. Another method of forming the wire is shown in FIG. The electric wire 3 is pressed into a mold 6 which has been processed into an R shape in advance, with both ends of the electric wire being fixed, and is formed into an R shape. According to this method, although the R diameter is constant and the conductor occupation ratio of the coil is increased, the dimensional accuracy of the straight portion and the R portion is improved, and the automation of the apparatus is facilitated.

  Yet another method is shown in FIG. An electric wire is formed using the R-type 6 shown in FIG. 5, but one end is fixed in advance, and a die 7 that moves around the R-type 6 forms the electric wire. Further, as shown in FIG. 7, the R-type 6 itself may be rotated to form the electric wire. In any case, the R shape has a characteristic that all are determined by the R of the mold 6.

  As a method of freely changing the R shape, there is a method of forming using a rotating roller 5 as shown in FIG. In order to obtain a desired R shape, the dimension between the rollers is changed to determine R. 9 (a) to 9 (e), the R forming method is such that the ends of the electric wire are fixed at the pitch of the arc length of the R-shaped portion, the bending moment is applied to both ends, and the R shape is formed. The shapes (c) and (d) of the bent portions to be formed are different depending on the holding intervals L1 (a) and L2 (b). Since the cross-sectional shapes of the electric wires are all constant and the material is also constant, a stable R dimension can be formed.

  FIG. 10 shows a cross section of the coil formed by the above-described forming method, and FIG. 11 shows a cross section of the coil formed by FIG. 5, FIG. 6, and FIG. The feature of the coil is determined by whether the R shape is constant or variable.

  A second embodiment will be described. In the automation of winding, when winding up to the number of tap wire pulling is performed manually using the above method, winding after the tap wire is wound edgewise until the tap wire is drawn and flat after the tap wire. There is also a method of molding with. According to this method, efficient winding is possible by a combination of automatic and manual. A cross-sectional view is shown in FIG.

  The resin casting method after winding is shown in FIGS. Since the coil 1 can be formed without using a mold, the coil 1 can be processed without using a mold, and the rotation rate of the mold is improved. In production, it is possible to reduce the number of molds held and to reduce costs such as expenses. In addition, forming the coil 1 without using a mold makes it possible to store the coil as a component, and even if the number of turns changes according to the voltage specifications, the prepared coil can be modified to shorten the coil production lead time. I can do it.

  A space between the mold and the winding coil is secured by a resin spacer, and a mold in which an outer mold is formed is used, so that a space is available and the casting resin is filled in the space. The coil formed in the edgewise direction does not bulge at the time of winding, and the dimension of the long side of the electric wire is reflected in the coil thickness. Therefore, the coil thickness accuracy is improved. This also leads to an improvement in the accuracy of assembly of the coil forming operation, the iron core, metal fittings, and terminals in the post-process, thereby improving work efficiency and reducing man-hours.

  A third embodiment will be described. The present embodiment does not require a winding die, and can be stored in a state where the conductor is molded, and can be prepared. Rather than starting the winding when the voltage specification at the time of the order is determined, as shown in FIGS. 15 and 16, coils having the same cross-sectional shape are continuously formed and stored in advance, and the desired coil A method of manufacturing a product coil is possible by cutting it a number of times and casting it. As a result, the production lead time can be shortened. FIG. 17 shows an external view of the transformer 11 using the present invention.

The coil sectional view of the mold coil of Example 1. FIG. The coil perspective view of the mold coil of Example 1. FIG. The coil perspective view after the end of tap wire formation in Example 1. FIG. FIG. 3 is an explanatory diagram illustrating an example of a coil forming unit of the molded coil according to the first embodiment. Explanatory drawing of the 2nd example of the means to coil-mold the mold coil of Example 1. FIG. Explanatory drawing of the 3rd example of the means to coil-mold the mold coil of Example 1. FIG. Explanatory drawing of the 4th example of the means to coil-mold the mold coil of Example 1. FIG. Explanatory drawing of the 5th example of the means to coil-mold the mold coil of Example 1. FIG. Explanatory drawing of the 6th example of the means to shape the coil of the mold coil of Example 1. FIG. The coil sectional view of the mold coil of Example 1. FIG. The coil sectional view of the mold coil of Example 1. FIG. Explanatory drawing of an example of the means for coil casting in the mold coil of Example 2. FIG. Explanatory drawing of another example of the coil casting means of the mold coil of Example 2. FIG. The coil sectional drawing of the mold coil of Example 2. FIG. The coil perspective view of the mold coil of Example 3. FIG. The cutting coil perspective view of the mold coil of Example 3. FIG. Explanatory drawing of the mold transformer assembled using the mold coil of Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Electric wire coil 2 ... Resin layer 3 ... Flat wire 4 ... Electric wire shaping | molding part 5 ... Roller 6 ... R shaping | molding die 7 ... Electric wire shaping die 8 ... Clamp 9 ... Mold for casting 10 ... Winding coil after tapping wire 11 ... Mold Transformer

Claims (4)

In a resin molded coil comprising a coil formed by winding a conductor, and an insulating layer formed on the inner periphery and outer periphery of the coil,
The coil is formed by axially laminating a coil portion wound a plurality of times from the outer periphery in the radial direction toward the inner periphery and a coil portion wound a plurality of times from the inner periphery toward the outer periphery, Molded coil, characterized in that the coil is covered with resin to insulate it. The molded coil according to claim 1, wherein
The said element wire consists of a cross section of a rectangular wire, and was bent and wound in the edgewise direction, The molded coil characterized by the above-mentioned. The molded coil according to claim 2,
The molded coil, wherein each of the coil portions is wound in a rectangular shape including a linear portion and an arc portion. The molded coil according to claim 2,
The said coil has the part wound by edgewise, the part wound by flatwise, and the tap wire drawer | drawing-out part provided between both parts, The molded coil characterized by the above-mentioned.

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