JP2005252107A - Electromagnetic inductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electromagnetic inductor capable of eliminating the need for an insulation coat of lead wires at the inner circumferential part of the winding without incurring reduction in a core effective cross-sectional area. <P>SOLUTION: The electromagnetic inductor is provided with the winding 4, a bobbin 1 onto which the winding 4 is loaded, and an EE or EI shaped core 2 the middle leg part 8 of which is inserted to an insertion hole 7 of the bobbin 1. The cross section of the middle leg part 8 is shaped almost rectangle. A lead-out groove 20, open to a side direction and reaching the inner circumferential part of the winding 4, is formed to a terminal board 18 of the bobbin 1 to which terminals 19 are placed at a position opposed to one side 8a of the middle leg part 8. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electromagnetic inductor such as a transformer that is reduced in size and thickness.

  As this type of electromagnetic induction device that is reduced in size and thickness, an electromagnetic induction device including a bobbin 40A shown in FIG. 6A and an E-shaped core piece 41A shown in FIG. The E-shaped core piece 41A is configured as an EE-shaped core or an EI-shaped core in combination with the E-shaped core piece 41A or the I-shaped core piece having the same shape as the E-shaped core piece 41A. The outer leg part 44 and the arm part 43 which connects both 42 and 44 are provided. The E-shaped core piece 41A is set so that the width of the middle leg portion 42, that is, the diameter is set smaller than the vertical width of the arm portion 43, and the arm portion 43 is notched along the tangent line of the outer surface of the middle leg portion 42. 43a is formed. On the other hand, the bobbin 40A has flange portions 47, 47 at both ends (both ends in the front and back directions in the figure) of the cylindrical winding tube portion 46 that forms the insertion hole 45 into which the middle leg portion 42 is inserted. A winding 48 is wound around the winding tube portion 46. In the winding 48, a secondary winding 48b is wound around the outer periphery of the primary winding 48a via an insulating tape.

  The bobbin 40A has a plurality of pin terminals 49 mounted in a row on each side on both sides in the width direction (vertical direction in the figure), and between each two adjacent pin terminals 49, The lead-out grooves 50 and 51 are formed, and further, a notch 52 having a shape corresponding to the notch 43a of the E-shaped core piece 41A is formed at the center of each side on both sides. Of the respective drawing grooves 50 and 51, only the first first drawing groove 50 has a groove depth reaching the innermost peripheral portion of the winding tube portion 46, that is, the winding 48, and the other second drawing grooves. 51 has a groove depth shallower than that of the first extraction groove 50.

  The upper lead wire 48aa shown in FIG. 6A is the winding start side drawn out from the innermost peripheral portion of the primary winding 48a, and the second lead wire 48aa is covered with an insulating material 53 made of a tube or tape. The lead is led to the lead groove 51, pulled out from the second lead groove 51, and soldered to the lead pin terminal 49. In this way, the lead wire 48aa is covered with the insulating material 53 because the lead wire 48aa is wound over the winding 48 in an arrangement straddling between the winding start portion and the winding end portion where the potential difference exists in the primary winding 48a. This is because if the electrode is pulled out in direct contact with the axial end face, dielectric breakdown may occur with the primary winding 48a. The lead wire 48ab at the end of the winding of the primary winding 48a is drawn out from the first lead groove 50 and soldered to another pin terminal 49. The lower lead wires 48ba and 48bb are the winding start side and the winding end side of the secondary winding 48b, and are drawn from the first and first lead grooves 51 and 50, respectively, and soldered to the pin terminal 49.

In addition, as another means of pulling out to the pin terminal while insulating the lead wire of the inner peripheral part of the winding, between the E type core piece and the I type core piece in the EI type core, An insulating sheet provided with a notch at an opposing position is interposed, and the lead wire of the inner periphery of the winding is drawn out from the notch to the opposite side of the insulating sheet, and between the insulating sheet and the I-shaped core piece. A configuration is also known in which the pin terminal is pulled out to the pin terminal (see Patent Document 1).
JP-A-6-132147

  However, in the electromagnetic induction device having the bobbin 40A and the E-shaped core piece 41A shown in FIG. 6, the bottom surface of the notch 43a of the arm portion 43 shown in FIG. 6B is tangent to the middle leg portion 42 of the E-shaped core piece 41A. In the bobbin 40 having the cutout 52 having a shape corresponding to the cutout 43 a of the E-shaped core piece 4, the groove bottom of the first lead-out groove 50 is formed only at the apex A of the insertion hole 45. When the outer peripheral surface of the winding tube part 46 is flush with the outer peripheral surface of the winding tube part 46, the groove bottom of the first drawing groove 50 is shifted radially outward from the outer peripheral surface of the winding tube part 46.

  Therefore, when the lead position 48aa at the innermost peripheral portion of the primary winding 48a slightly deviates from the apex A, the lead line 48aa crosses a part of the primary winding 48a in the radial direction. Therefore, as shown in FIG. 6A, the primary winding 48 a must be covered with the insulating material 53. As a result, not only is it difficult to automate the winding process of the winding 48, but the lead wire 48 aa covered with the insulating material 53 overlaps a part of the axial end surface of the winding 48. The alignment becomes worse.

  Therefore, as shown in FIG. 7B, a cutout 43b is formed in the arm portion 43 so that portions 42a on both the upper and lower sides of the middle leg portion 42 protrude vertically in the E-shaped core piece 41B. As shown in a), by providing the bobbin 40B with a notch 52 having a shape corresponding to the notch 43b of the E-shaped core piece 41B, the outer peripheral surface of the winding tube portion 46, that is, the inner peripheral surface of the winding 48 is provided. There has also been proposed an electromagnetic inductor provided with a first extraction groove 50 having a reaching groove depth. In this electromagnetic inductor, the lead wire 48aa from the innermost peripheral portion of the primary winding 48a is directly pulled out of the bobbin 40B through the first lead groove 50 without overlapping the axial end surface of the primary winding 48a. Therefore, it is not necessary to cover with the insulating material 53.

  However, in this electromagnetic inductor, the upper and lower sides 42a of the middle leg portion 42 of the E-shaped core piece 41B in FIG. 7B protrude outward from the notch 43b of the arm portion 43. As a result of the magnetic flux passing through the portion 42a protruding outward from the position indicated by the two-dot chain line becoming difficult to flow toward the outer leg portions 44 on both sides, the magnetic loss increases. Therefore, the effective cross-sectional area of the middle leg portion 42 in the E-shaped core piece 41B is small except for the portions 42a on both sides. In an electromagnetic inductor such as a transformer, the magnetic capacity is proportional to the cross-sectional area of the core constituting the magnetic circuit. Therefore, when the E-shaped core piece 41B of FIG. Thus, a high-performance electromagnetic inductor cannot be obtained.

  Further, in the electromagnetic inductor in which the lead wire is insulated by the insulating sheet described in Patent Document 1, the number of parts increases by the amount of the insulating sheet, and the lead wire passes between the insulating sheet and the core piece. Therefore, the assemblability is poor, and the thickness of the winding in the winding axis direction is increased by the thickness of the insulating sheet.

  The present invention has been made in view of the above-described conventional problems, and provides an electromagnetic inductor that can eliminate the need for insulating coating of the lead wire of the inner peripheral portion of the winding without reducing the effective cross-sectional area of the core. It is intended to provide.

  To achieve the above object, an electromagnetic inductor according to the present invention includes a winding, a bobbin to which the winding is mounted, and an EE type or EI type core in which a middle leg portion is inserted into an insertion hole of the bobbin. The cross-sectional shape of the middle leg portion is substantially a quadrangle, and the side portion of the bobbin on which the terminal is mounted is located on the side facing the one side of the middle leg portion. A lead-out groove is formed that opens in the direction toward the inner periphery of the winding.

  In this electromagnetic inductor, the cross-sectional shape of the middle leg portion is substantially quadrilateral, and at the position facing one side of the middle leg portion, a drawer groove is formed that opens to the side and reaches the inner peripheral portion of the winding. Therefore, the groove bottom of the lead-out groove is flush with the inner peripheral surface of the winding over a wide range. Therefore, the lead wire on the winding start side, which is led out from the inner periphery of the winding, is led out directly from the pulling position of the inner periphery through the lead-out groove without overlapping the end face of the winding, and then to the terminal. Since it can be connected, there is no need to cover it with an insulating material. At that time, even if the drawing position of the lead wire is slightly shifted in the circumferential direction of the winding, it does not overlap with the end face of the winding, so insulation is ensured. The For this reason, this electromagnetic inductor eliminates the need for covering the lead wire with an insulating material, thereby making it possible to easily automate the winding process of the winding and to improve the alignment of the winding. Along with this, the windings can be wound in close contact with each other, so even when the number of turns is increased using a wire with a large wire diameter, the overall winding diameter becomes large and bulky. There is no. Thus, when a wire with a large wire diameter is used, the electrical resistance is reduced and heat generation when the temperature rises can be suppressed. When the number of turns is increased, the saturation current is increased and the direct current superimposition is improved. There are advantages.

  In addition, as described above, since the groove bottom of the drawer groove is flush with the inner peripheral surface of the winding over a wide range, large notches on both sides of the middle leg portion as shown in FIG. Since the entire cross-sectional area of the middle leg portion can be ensured as an effective sectional area, a required magnetic capacity can be maintained.

  In preferable embodiment of this invention, the width | variety of the said middle leg part of the E-shaped core piece which forms the said core is set smaller than the width | variety of an arm part. According to this configuration, since the width of the winding disposed on the outer periphery of the middle leg portion is also reduced, the electromagnetic induction device can be reduced in size.

  In a preferred embodiment of the present invention, the bobbin has a standing wall along the side surface of the arm portion of the E-shaped core piece that forms the core, and the drawer groove reaches the outer surface of the standing wall. According to this configuration, the insulating property between the arm portion of the E-shaped core piece and the terminal is improved by the standing wall.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an exploded perspective view showing an electromagnetic inductor according to a first embodiment of the present invention. The electromagnetic inductor includes a pair of E-shaped core pieces 3A and 3A in which middle legs 8 and 8 are inserted into a bobbin 1, a winding 4 attached to the bobbin 1, and an insertion hole 7 of the bobbin 1, respectively. EE type core 2 which consists of these. The E-shaped core piece 3A is obtained by connecting a central middle leg portion 8 and a pair of outer leg portions 10 on both sides thereof by arm portions 9, and the outer leg portions 10 are provided at both ends of the substantially rectangular parallelepiped arm portion 9. The middle leg portion 8 protrudes from the central portion of the arm portion 9 so as to extend in parallel in the same direction, and has an E shape in a side view.

  The middle leg portion 8 of the E-shaped core piece 3A has a rectangular column shape having a substantially rectangular cross-sectional shape in which four rectangular corner portions are obliquely cut (chamfered), and is larger than the width C of the arm portion 9. A small width D is set. The planar side surfaces 8a and 8a forming two sides located on both sides in the width direction of the middle leg portion 8 are exposed to the outside (vertical direction), and the left and right sides of the planar side surfaces 8a and 8a are left and right. Both end portions and the side surface of the arm portion 9 are connected by a notched slope 11.

  On the other hand, the bobbin 1 is integrally formed with winding frame flanges 13 and 14 at both ends of a rectangular tube-shaped winding tube portion 12 whose inside is the insertion hole 7 so as to be parallel to each other. A winding frame portion surrounded by 12 and a pair of winding frame flanges 13 and 14 is formed, and a winding 4 is wound around the winding frame portion. On one side (the front side in the figure), the shape of the reel part 14 corresponding to the side surface shape in the length direction (left and right direction in the figure) of the E-shaped core piece 3A, that is, the shape along the side surface of the arm part 9 is obtained. The standing wall 17 is integrally formed. That is, the pair of upright walls 17 and 17 has an inward recess 17a having a shape corresponding to the cut-out slope 11 of the E-shaped core piece 3A and the planar side surface 8a of the middle leg portion 8 at the center, In a state where the middle leg portion 8 is inserted into the insertion hole 7, the arm portions 9 of the E-shaped core piece 3 </ b> A are opposed to each other with an interval between them.

  Terminal blocks 18 and 18 are formed on the outer side portions of the standing walls 17 and 17 in one reel portion 14 of the bobbin 1, and each of the terminal blocks 18 has five pin terminals (terminal terminals). (Example) 19 are planted in a single row, and lead-out grooves 20 and 21 are formed between the two adjacent pin terminals 19 in the terminal blocks 18 and 18, respectively. The first drawer groove 20 facing the recess 17a of the standing wall 17 has a groove depth reaching the standing wall 17 and is provided on each of two sides. Except for the first drawer groove 20, the second drawer groove 21 has a groove depth shallower than the first drawer groove.

  As shown by arrows, the electromagnetic inductor inserts the middle leg portion 8 of each of the pair of E-shaped core pieces 3A, 3 into the insertion hole 7 of the bobbin 1, and the pair of outer leg portions 10, 10 respectively. 2 are assembled as shown in FIG. 2 by fitting the pair of E-shaped core pieces 3A and 3A with the bobbin 1 sandwiched between them along the left and right outer surfaces of the bobbin 1. The pair of E-shaped core pieces 3A and 3A are assembled to the EE-shaped core 2 by being coupled to each other, thereby forming a magnetic circuit.

  FIG. 3 is a bottom view of the state where the lower E-shaped core piece 3A of FIG. 2 is excluded. A lower E-shaped core piece 3 </ b> A (not shown in the figure) fits between the pair of standing walls 17, 17 of the bobbin 1. The outer periphery of the straight portion in the recess 17 a of the pair of standing walls 17 is flush with the outer surfaces of the upper and lower portions of the winding tube portion 12. Therefore, the two first lead grooves 20 facing the recess 17a of the standing wall 17, that is, facing the planar side surface 8a of the E-shaped core piece 3A, are formed on the winding 4 wound around the winding cylinder portion 12. The groove depth reaches the innermost periphery.

  In the winding 4, the secondary winding 4 b is wound around the outer periphery of the primary winding 4 a via the insulating tape 31, and the thickness in the winding axis direction of the winding 48 is reduced by such radial lap winding. Therefore, the thickness is reduced. An insulating tape 32 is wound around the outer periphery of the secondary winding 4b. The lead wire 4aa on the winding start side of the primary winding 4a was drawn out from the innermost peripheral portion of the primary winding 4a onto the terminal block 18 through one (right side) first lead groove 20 of the upper two. After that, it is connected to the pin terminal 19 by soldering. The lead wire 4ab on the winding end side of the primary winding 4a is drawn onto the terminal block 18 through one of the two lower (right) first drawing grooves 20, and then connected to the pin terminal 19 by soldering. Has been. The lead wire 4ba on the winding start side of the secondary winding 4b is drawn onto the terminal block 18 through the other lower (left) first lead groove 20 and then connected to the pin terminal 19 by soldering. The lead wire 4bb on the winding end side of the next winding 4b is drawn onto the terminal block 18 through the one second (left side) second lead groove 21 and then connected to the pin terminal 19 by soldering.

  The lead-out line 4aa on the winding start side of the primary winding 4a has a lead-out position at the innermost peripheral portion in the primary winding 4a, but to the outer peripheral surface of the winding cylinder portion 12, that is, the inner peripheral portion of the primary winding 4a. Since it is pulled out through the first lead-out groove 20 having the groove depth to reach, as shown in FIG. 2, after being pulled out directly from the pull-out position through the first lead-out groove 20 in the axial direction (downward direction in FIG. 2), the pin terminal 19 is connected. Accordingly, the lead wire 4aa on the winding start side of the primary winding 4a in FIG. 3 does not come into contact with the end face of the primary winding 4a, so that coating with an insulating material becomes unnecessary.

  In the above configuration, since the middle leg portion 8 of the E-shaped core piece 3A shown in FIG. 1 is formed in a substantially square cross-sectional shape, the planar side surface 8a that forms two opposite sides of the middle leg portion 8 is formed. Although the entire surface is exposed, unlike the conventional example shown in FIG. 7, the planar side surface 8 a does not protrude outward from the contact with the notched slope 11 of the arm portion 9. Accordingly, the middle leg portion 8 of FIG. 1 can effectively constitute a magnetic circuit as a whole even though the entire planar side surface 8a is exposed. That is, the entire cross-sectional area of the middle leg portion 8 is the effective sectional area. As a result, the EE type core 2 composed of the pair of E type core pieces 3A and 3A maintains a required magnetic capacity and improves the magnetic characteristics of the electromagnetic inductor.

  Further, in the electromagnetic induction device, the cross-sectional shape of the middle leg portion 8 is substantially quadrangular, and a first opening that opens to the side and reaches the inner peripheral portion of the winding 4 at a position facing one side of the middle leg portion 8. Since the drawing groove 20 is formed, the groove bottom of the first drawing groove 20 is flush with the inner peripheral surface of the winding 4 over a wide range. Accordingly, the lead wire 4aa on the winding start side of the primary winding 4a led out from the inner peripheral portion of the winding 4 extends outwardly from the lead position of the inner peripheral portion through the first lead groove 20 and the end face of the winding 4. Since it can be connected directly to the pin terminal 19 without being overlapped, it is not necessary to cover it with an insulating material. At this time, even if the lead position of the lead wire 4aa is slightly shifted in the circumferential direction of the winding 4, the winding Since no overlap with the end face of 4 occurs, insulation is ensured.

  The electromagnetic induction device can easily automate the winding process of the winding 4 by eliminating the need for covering the lead wires 4aa and 4ba with an insulating material. In addition, the winding 4 does not have a winding disorder as in the case where the lead wire covered with the insulating material is drawn through between the end face of the winding and the bobbin reel part of the bobbin as in the conventional case, so that the alignment property is improved. improves. Along with this, the winding 4 can be wound in close contact with each other. Therefore, even when the number of turns is increased using a wire having a large wire diameter, the entire winding diameter becomes large and bulky. It will never be. Thus, when a wire with a large wire diameter is used, the electrical resistance is reduced and heat generation when the temperature rises can be suppressed. When the number of turns is increased, the saturation current is increased and the direct current superimposition is improved. There are advantages.

  Further, in the electromagnetic inductor, since the width D of the middle leg portion 8 of the E-shaped core piece 3A is set smaller than the width C of the arm portion 9, the winding 4 disposed on the outer periphery of the middle leg portion 8 Therefore, the electromagnetic inductor can be downsized. Further, in this electromagnetic inductor, the bobbin 1 has the standing wall 17 along the side surface of the arm portion 9 of the E-shaped core piece 3A that forms the core 2, so that the arm portion 9 of the E-shaped core piece 3 is supported by the standing wall 17. And the pin terminal 19 are improved in insulation.

  FIGS. 4A and 4B are perspective views showing other examples of E-shaped core pieces 3B and 3C that can be used in place of the E-shaped core piece 3A of the embodiment. The E-shaped core piece 3B in FIG. 11A is formed in a shape in which the middle leg portion 8 has a rectangular cross-sectional shape with no chamfered corners, and the E-shaped core piece 3C in FIG. The middle leg portion 8 is formed in a shape having a cross-sectional shape in which four corners of a rectangle are chamfered in a round shape. In any of the E-shaped core pieces 3B and 3C, the planar side surface 8a facing the width direction of the middle leg portion 8 is exposed to the side by the cut-out slope 11 of the arm portion 9. , 3C can also be used to obtain the same effect as described in the above embodiment.

  In the above embodiment, the case where the EE type core 2 in which a pair of E type core pieces 3A is combined is used has been described as an example, but the same as that disclosed in the above-mentioned Japanese Patent Laid-Open No. 6-132147, Even when the EI type core 2A in which the E type core piece 3A and the I type core piece 3D shown in FIG. 5 are combined is used, the same effect as described above can be obtained.

  In addition to the transformer, the present invention can also be applied to induction ceramics such as a choke coil and a reactor.

It is a disassembled perspective view which shows the electromagnetic inductor which concerns on 1st Embodiment of this invention. It is a side view of an electromagnetic inductor same as the above. It is a bottom view which excludes and shows one E-shaped core piece of an electromagnetic inductor same as the above. (A), (b) is a perspective view which shows the modification of an E-shaped core piece, respectively. It is a disassembled perspective view which shows EI type | mold core of the electromagnetic inductor which concerns on 2nd Embodiment of this invention. (A), (b) is the top view and perspective view which respectively show the bobbin and core piece which comprise the conventional electromagnetic inductor. (A), (b) is a top view which shows the bobbin and core piece which comprise the other conventional electromagnetic inductor, respectively.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Bobbin 2 EE type | mold core 2A EI type | mold core 3A-3C E type | mold core piece 3D I type | mold core piece 4 Winding 7 Insertion hole 8 Middle leg part 9 Arm part 17 Standing wall 18 Side part 18a Planar side (one side)
19-pin terminal (terminal)
20 First drawer groove (drawer groove)
D Width of middle leg C Width of arm

Claims (3)

An electromagnetic inductor comprising a winding, a bobbin to which the winding is mounted, and an EE type or EI type core in which a middle leg portion is inserted into an insertion hole of the bobbin,
The cross-sectional shape of the middle leg portion is substantially square,
An electromagnetic induction device in which a lead groove is formed in a side portion of the bobbin where a terminal is mounted, at a position facing one side of the middle leg portion, and opens laterally to reach an inner peripheral portion of the winding.   2. The electromagnetic inductor according to claim 1, wherein a width of the middle leg portion of the E-shaped core piece forming the core is set smaller than a width of the arm portion. 3. The electromagnetic induction device according to claim 1, wherein the bobbin has a standing wall along a side surface of an arm portion of an E-shaped core piece forming the core, and the drawing groove reaches the outer surface of the standing wall.

Images