JP2018101750A - Coil device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coil device with stable leakage characteristics.SOLUTION: A transformer 10 has a bobbin 20 and a coil 300 mounted on the outer circumference of the bobbin 20. The coil 300 has, along a winding axis of the coil 300, a first coil portion 301, a second coil portion 302, and an intermediate coil portion 303 positioned between the first coil portion 301 and the second coil portion 302. The intermediate coil portion 303 is constituted by an intermediate wire 37. The first coil portion 301 and the second coil portion 302 are formed of a common wire 38 for forming the first coil portion 301 and the second coil portion 302.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a coil device that can be suitably used as a transformer such as a leakage transformer.

  Coil devices are used for various applications in various electrical products. For example, coil devices are used in EV (Electric Vehicle), PHV (Plug-in Hybrid Vehicle) or in-vehicle chargers for commuter (vehicle), LLC circuits, etc., and leakage It is generally used as a transformer such as a transformer.

  As a coil device, for example, a coil device shown in Patent Document 1 shown below is known. In the coil device shown in Patent Document 1, the leakage characteristics can be easily adjusted, and it is possible to cope with higher frequencies while increasing the current.

  However, in the coil device shown in Patent Document 1, when the primary coil and the secondary coil are arranged adjacent to each other in the winding axis direction, and the winding ratio is different, the coupling between these coils is limited. It has been found that the leakage characteristic tends to be low and the leakage characteristics may not be stable. Particularly in recent years, with the increase in the frequency of the voltage applied to the coil device, the stability of the leakage characteristics in the high frequency band has become a problem.

Japanese Patent Laying-Open No. 2015-65413

  The present invention has been made in view of such a situation, and an object thereof is to provide a coil device having a stable leakage characteristic.

In order to achieve the above object, a coil device according to the present invention comprises:
A first coil part;
A second coil part, which is made of the same common wire as the wire constituting the first coil part, and is arranged away from the first coil part along a winding axis;
An intermediate coil portion that is located between the first coil portion and the second coil portion along the winding axis and is formed of an intermediate wire different from the common wire.

  In the coil device according to the present invention, the intermediate coil portion is sandwiched between the first coil portion and the second coil portion. Therefore, the coupling between these coils can be increased, and it becomes easy to stabilize the leakage characteristics. Further, it is possible to realize a coil device that can obtain a stable leakage characteristic even in a high frequency band.

  Moreover, the 1st coil part and the 2nd coil part are continuously formed with the common wire. By adopting such a configuration, it is possible to prevent the current from flowing in one of the first coil portion and the second coil portion. Since current is prevented from flowing unevenly, it is possible to prevent any one of the coil portions from generating abnormal heat. In addition, compared to the case where the first coil unit and the second coil unit are configured with separate wires, the wire length of the common wire that configures the first coil unit and the second coil unit can be shortened. Copper loss can be reduced. If the copper loss can be reduced, efficiency can be improved and heat generation can be reduced.

  Preferably, the common wire is α-wound around a bobbin. By setting it as such a structure, the 1st coil part and 2nd coil part which are arrange | positioned away in the winding axis direction can be easily formed using a single common wire. Moreover, it is easy to make the number of coil turns the same in the first coil part and the second coil part, and it is also easy to change the number of turns.

  Further, in each of the first and second coil sections, the bobbin ridge interval is adjusted so that only a single wire exists along the winding axis direction, thereby varying the number of windings of the wire per layer. Can be easily prevented, and contributes to the stabilization of leakage characteristics. That is, it becomes easy to strictly control the coupling coefficient between the primary coil and the secondary coil.

  In addition, the α winding contributes to a reduction in the height and size of the coil device because the number of layers in the winding axis direction can be reduced even if the number of turns is increased. Furthermore, since the wire is not drawn out from the center of the winding by using α winding, the wires do not overlap, contributing to a reduction in the height of the coil device.

  The number of turns of the common wire in the first coil part and the second coil part may be different from the number of turns of the intermediate wire in the intermediate coil part. In the coil device of the present invention, since the coupling between the coils is high, it is easy to stabilize the leakage characteristics even in the above configuration. That is, according to the present invention, a remarkable effect is obtained when the turn ratio between the number of turns of the common wire in the first coil part and the second coil part and the number of turns of the intermediate wire in the intermediate coil part is large. When it is set as the said structure, a 1st coil part and a 2nd coil part may be comprised by multiple turns, and an intermediate | middle coil part may be comprised by 1 turn. In the conventional coil device, when the turn ratio of the primary coil and the secondary coil is increased, the coupling between the coils is lowered, and it may be difficult to stabilize the leakage characteristics.

  Preferably, the common wire has an inter-coil connection portion extending in the winding axis direction between the first coil portion and the second coil portion. Since the first coil portion and the second coil portion are continuously formed with a common wire, the common wire has an inter-coil connection extending in the winding axis direction between the first coil portion and the second coil portion. Part is formed.

  Preferably, the inter-coil connection portion passes through the inside of the intermediate coil portion. In that case, the first coil portion and the second coil portion are first formed using the common wire, and then the intermediate wire is wound around the bobbin to form the intermediate coil portion. In this case, the inter-coil connecting portion passes through the inside of the intermediate coil portion.

  In addition, the aspect which winds an intermediate wire first, comprises an intermediate coil part, and then winds a common wire, and comprises a 1st coil part and a 2nd coil part is also considered. In this case, the inter-coil connecting portion passes outside the intermediate coil portion.

  The coil device of the present invention may have a first insulating cover for insulating the inter-coil connecting portion from the intermediate coil portion. By interposing the first insulating cover so that the inter-coil connecting portion and the intermediate coil portion are isolated, the insulation between them can be ensured.

  The lead portion of the intermediate wire may have a raised portion extending in the winding axis direction. Preferably, a second insulating cover is interposed between the upright portion and the first coil portion. The rising portion can be reliably insulated by interposing the second insulating cover so as to be separated from the first coil portion while being drawn out upward of the coil.

  The common wire may constitute either one of a primary coil or a secondary coil, and the intermediate wire may constitute either the primary coil or the secondary coil. By comprising in this way, a 1st coil part and a 2nd coil part are made into a primary coil, an intermediate coil part is made into a secondary coil, or an intermediate coil part is made into a primary coil, and a 1st coil part and a 1st coil A 2 coil part can be used as a secondary coil.

FIG. 1 is a perspective view of a transformer as a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the transformer shown in FIG. FIG. 3 is a perspective view when the case is removed from the transformer shown in FIG. FIG. 4 is a perspective view when the core is removed from the transformer shown in FIG. FIG. 5 is a cross-sectional view of the main part of the transformer along the line VV shown in FIG. 6A is a cross-sectional view of a main part of the transformer taken along line VI-VI shown in FIG. 6B is a cross-sectional view of the main part of the bobbin along the line VI-VI shown in FIG. 7A is a perspective view of a bobbin and the like in the transformer shown in FIG. FIG. 7B is a perspective view of the bobbin shown in FIG. 7A when viewed from another angle. FIG. 7C is a perspective view of the insulating cover and the like shown in FIG. 6A. FIG. 7D is a perspective view of another insulating cover shown in FIG. 6A. FIG. 8A is a perspective view showing an example of a common wire and an intermediate wire wound around the bobbin shown in FIG. 7A. 8B is a perspective view showing the positional relationship between the common wire and the intermediate wire shown in FIG. 8A and the insulating cover shown in FIGS. 7C and 7D. FIG. 8C is a perspective view of the common wire or the like shown in FIG. 8B when viewed from another angle. FIG. 9 is a side view of the common wire and the intermediate wire shown in FIG. 8A. 10 is an exploded perspective view of the common wire and the intermediate wire shown in FIG. 8A. FIG. 11 is a circuit diagram showing an equivalent circuit of the transformer shown in FIG.

  Hereinafter, the present invention will be described based on embodiments shown in the drawings.

  A transformer 10 as a coil device according to the present embodiment shown in FIG. 1 includes, for example, an EV (Electric Vehicle), a PHV (Plug-in Hybrid Vehicle), or a vehicle mounted on a commuter (vehicle). For example, it is used for constituting a part of an LLC circuit.

  As shown in FIG. 2, the transformer 10 includes a bobbin 20, magnetic cores 40a and 40b, a cover 50, a lead wire cover 60, a pedestal 70, a case 90 that accommodates them, and a bottom plate 92. Have In the drawing, the X axis, the Y axis, and the Z axis are perpendicular to each other, and the Z axis corresponds to the height (thickness) of the transformer 10. In the present embodiment, the lower side of the transformer 10 in the Z-axis direction is the installation surface of the transformer. Further, the Y axis coincides with the longitudinal direction of the base portions 44a and 44b in the magnetic cores 40a and 40b. Further, the X axis is adapted to coincide with the longitudinal direction of the bobbin 20.

  In this embodiment, the base plate 92 is attached to the bottom opening of the case 90 by means such as caulking or bonding, and the case 90 having an open top is configured. The bottom plate 92 is preferably made of a metal such as aluminum copper or iron having excellent heat dissipation, but may be made of PPS, PET, PBT, or the like. Since the bottom plate 92 comes into contact with the lower end surface of the magnetic core 40 described later in the Z-axis direction, the bottom plate 92 is preferably made of a material excellent in heat dissipation. A cooling device such as a cooling pipe or a cooling fin may be attached below the case 90 via the bottom plate 92 or directly.

  Boss portions 91 are formed in the vicinity of intermediate portions in the Z-axis direction at the four corners of the case 90. For example, a bolt hole is formed in the boss portion 91. The case 90 itself is made of metal, but may be made of synthetic resin or the like. The bottom plate 92 and the case 90 may be integrally formed by aluminum die casting or the like. By making the entire case out of metal, heat dissipation is further enhanced.

  The case 90 may be filled with a heat radiating resin. Although it does not specifically limit as resin for thermal radiation, For example, resin excellent in heat dissipation whose thermal conductivity is 0.5-5, Preferably it is 1-3 W / m * K is preferable. Examples of the resin excellent in heat dissipation include silicone resin, urethane resin, and epoxy resin, among which silicone resin and urethane resin are preferable. Moreover, in order to improve heat dissipation, the resin may be filled with a filler having high thermal conductivity.

  Moreover, it is preferable that the resin for thermal radiation of this embodiment has a Shore A hardness of 100 or less, preferably 60 or less. This is because even if the magnetic cores 40a and 40b and the bobbin 20 are deformed by heat, the deformation is absorbed and excessive stress is not generated in the magnetic cores 40a and 40b. An example of such a resin is a potting resin.

  As shown in FIGS. 5 and 6A, the coil 300 wound around the bobbin body 21 of the bobbin 20 includes the first coil portion 301 along the winding axis of the coil 300 (substantially parallel to the Z axis), It has the 2nd coil part 302 and the intermediate | middle coil part 303 located between these 1st coil parts 301 and the 2nd coil part 302. FIG. That is, in the present embodiment, the intermediate coil portion 303 is sandwiched between the first coil portion 301 and the second coil portion 302 along the winding axis (Z-axis direction) of the coil 300.

  The intermediate coil unit 303 is configured by an intermediate wire 37, and the first coil unit 301 and the second coil unit 302 are configured by a common wire 38 for forming the first coil unit 301 and the second coil unit 302. It is.

  In the present embodiment, the common wire 38 constitutes a primary coil, and the intermediate wire 37 constitutes a secondary coil. That is, as shown in FIG. 11, the first coil portion 301 and the second coil portion 302 configured by the common wire 38 are the primary side winding, and the intermediate coil portion 303 configured by the intermediate wire 37 is the secondary side winding. By forming a line, a transformer is formed between the two.

  In the present embodiment, a high voltage acts on the primary coil as compared with the secondary coil, and a relatively low voltage acts on the secondary coil. Here, La shown in FIG. 11 is a leakage inductance.

  Each of the wires 37 and 38 may be composed of a single wire, or may be composed of a stranded wire, or one may be a single wire and the other may be a stranded wire. Each wire 37, 38 may be made of the same material or different. Although the outer diameter of the wires 37 and 38 is not specifically limited, Preferably it is the range of 1.0-4.0 mm. In this embodiment, since the electric current which flows into a secondary coil becomes large, the outer diameter of the intermediate | middle wire 37 is larger than the outer diameter of the common wire 38, for example, 3.0-4.0 mm is preferable. Each wire 37, 38 is preferably provided with an insulating film.

  The first lead portions 37a and 37b shown in FIG. 1 are both end portions of the intermediate wire 37 shown in FIGS. 5 and 6A, and the second lead portions 38a and 38b shown in FIG. 1 are common to those shown in FIGS. It is the both ends of the wire 38. As shown in FIG. 1, a terminal 94 made of, for example, a metal terminal is connected to each end portion of the first lead portions 37a and 37b and the second lead portions 38a and 38b by soldering or the like. And both ends of 38 and 38 are electrically connected to the terminal 94.

  In the present embodiment, when the number of turns of the intermediate wire 37 constituting the intermediate coil part 303 is n2, the total number of turns n1 of the common wire 38 in the first coil part 301 and the second coil part 302 is preferably the number of turns n2. 2 times or more, 3 times or more, 5 times or more, 6 times or more. In the present embodiment, even when the ratio of the number of turns (n1 / n2) is large, the coupling coefficient can be made relatively large, which contributes to the stabilization of leakage characteristics.

  The total number of turns n1 of the common wire 38 in the first coil part 301 and the second coil part 302 is preferably divided approximately equally into the first coil part 301 and the second coil part 302, but may be slightly different. That is, the number of turns of the common wire 38 in the first coil part 301 is preferably (0.3 to 0.7) × n1, and the number of turns of the common wire 38 in the second coil part 302 is (0. 7 to 0.3) × n1 is preferable. This is to improve the coupling coefficient between the primary coil and the secondary coil.

  As shown in FIG. 9, the common wire 38 includes an inter-coil connection portion 380 that extends between the first coil portion 301 and the second coil portion 302 in the winding axis (Z-axis) direction. In the present embodiment, since the first coil portion 301 and the second coil portion 302 are continuously formed by the common wire 38, the common wire 38 has a space between the first coil portion 301 and the second coil portion 302. The inter-coil connection portion 380 extending in the winding axis direction is formed.

  As shown in FIGS. 6A and 9, the inter-coil connection portion 380 passes through the inside of the intermediate coil portion 303. Although details will be described later, in this embodiment, the common wire 38 is first wound around the bobbin 20 to form the first coil portion 301 and the second coil portion 302, and then the intermediate wire 37 is wound around the bobbin 20. Thus, the intermediate coil portion 303 is configured.

  When the coil 300 is mounted on the bobbin 20 in such a manner, the inter-coil connection portion 380 passes through the inside of the intermediate coil portion 303. In this case, as shown in FIG. 6A, a first insulating cover 81 is attached to the bobbin 20 in order to insulate the inter-coil connection portion 380 from the intermediate coil portion 303. The first insulating cover 81 will be described in detail later.

  As shown in FIG. 6A, a pair of first lead portions 38 a and 38 b are drawn out from the first coil portion 301 and the second coil portion 302. A pair of first lead portions 37 a and 37 b are drawn out from the intermediate coil portion 303.

  More specifically, as shown in FIG. 8A, the first lead portions 37a and 37b formed at both ends of the intermediate wire 37 are raised portions 371a and 371b extending in the winding axis (Z-axis) direction of the coil 300, respectively. It has direction change parts 372a and 372b which go in the direction where the space | interval of a pair of 1st lead parts 37a and 37b narrows, and extraction main-body parts 373a and 373b extended in the direction away from the coil 300 (X-axis).

  Note that the upright portions 371a and 371b are not necessarily parallel to the Z axis and may be inclined. Further, the drawer main body portions 373a and 373b are not necessarily parallel to the X axis, and may be inclined in the Y axis and / or Z axis direction. In addition, the direction changing portions 372a and 372b are portions that convert the direction toward the rising portions 371a and 371b into the direction toward the drawer main body portions 373a and 373b, and may be linear or curved.

  In this embodiment, it is comprised so that the space | interval of drawer main-body parts 373a and 373b may become narrower than the clearance gap between standing-up parts 371a and 371b. More specifically, the gap interval W1 between the drawer main body portions 373a and 373b is preferably 0 to 1 mm. The length L1 in the X-axis direction of the drawer main body portions 373a and 373b is preferably 20 to 100 mm. As the gap interval W1 is reduced, the leakage of the secondary coil can be reduced. Further, the length L1 in the X-axis direction of the drawer main body portions 373a and 373b is preferably the minimum necessary since the leakage tends to increase as the length increases.

  Further, as shown in FIG. 8A, the second lead portions 38a and 38b formed at both ends of the common wire 38 are paired with rising portions 381a and 381b extending in the winding axis (Z-axis) direction of the coil 300. Direction change portions 382a and 382b that extend in the direction in which the distance between the second lead portions 38a and 38b increases, and lead body portions 383a and 383b that extend in the direction away from the coil 300 (Y-axis).

  The upright portions 381a and 381b are not necessarily parallel to the Z-axis and may be inclined. Also, the drawer main body portions 383a and 383b are not necessarily parallel to the X axis, and may be inclined in the Y axis and / or Z axis direction. Moreover, the direction change parts 382a and 382b are the same as the direction change parts 372a and 372b, and may be linear or curved.

  In this embodiment, it is comprised so that the space | interval of drawer | drawing-out main-body parts 383a and 383b may become wider than the clearance gap between standing | upright parts 381a and 381b. More specifically, the gap interval W2 between the drawer main body portions 383a and 383b is wider than the gap interval W1 between the drawer main body portions 373a and 373b, and preferably 1 to 5 mm. The length L2 in the X-axis direction of the drawer main body portions 383a and 383b is substantially equal to the length L1 in the X-axis direction of the drawer main body portions 373a and 373b.

  In addition, in this embodiment, although the space | interval of drawer main-body parts 373a and 373b and the space | interval of drawer main-body parts 383a and 383b are constant in each part of the longitudinal direction, they may differ. That is, the drawer body portions 373a and 373b or the drawer body portions 383a and 383b do not necessarily extend in parallel. However, from the viewpoint of improving the leakage characteristics of the transformer 10, it is preferable that the gap interval W1 between the drawer main body portions 373a and 373b is reduced and the gap interval W1 is constant along the longitudinal direction.

  As shown in FIG. 7A, the bobbin 20 includes a bobbin main body 21 and terminal blocks 22 and 23 that are integrally formed on both upper ends of the bobbin main body 21 in the X-axis direction. The bobbin 20 is made of plastic such as PPS, PET, PBT, LCP, and nylon, but may be made of other insulating members. However, in this embodiment, the bobbin 20 is preferably made of a plastic having a high thermal conductivity of, for example, 1 W / m · K or more, and is made of, for example, PPS or nylon.

  The terminal blocks 22 and 23 have side wall portions 221 and 231 and a pair of locking portions 222 and 232 formed at both ends in the X-axis direction, respectively. The side wall portions 221 and 231 are formed so as to surround the peripheral edges of the terminal blocks 22 and 23 except for the side from which the first lead portions 37a and 37b and the second lead portions 38a and 38b are drawn. Engaging protrusions 224 and 234 are formed on both outer end walls in the Y-axis direction of the side walls 221 and 231, respectively. The functions of the engaging protrusions 224 and 234 will be described later. In the terminal block 22, a separation protrusion 223 is formed at an intermediate position in the Y-axis direction between the pair of locking portions 222.

  As shown in FIG. 7B, the pair of locking portions 222 includes first lead portions 37a and 37b raised in the Z-axis direction by the upright portions 371a and 371b, and Y-axis at the portions of the direction change portions 372a and 372b. It is wound inward from the outside in the direction, and is guided to the outside in the X-axis direction in a state where the gap between the drawer main body portions 373a and 373b is reduced.

  The separation convex portion 223 has a substantially pentagonal shape when viewed from the Z axis, and has a tip portion that tapers in a direction away from the bobbin 20 in the X axis direction. The separation convex portion 223 is a member for separating the direction change portions 372a and 372b or the drawer main body portions 373a and 373b so as not to contact each other. Note that the shape of the separation convex portion 223 is not limited to the shape shown in the figure, and may be appropriately changed to an elliptical shape or other polygonal shapes.

  By engaging the direction change portions 372a and 372b of the first lead portions 37a and 37b with the pair of locking portions 222, the first lead portions 37a and 37b are configured by an intermediate wire 37 positioned in the middle of the first lead portions 37a and 37b shown in FIG. 8A. Unwinding of the intermediate coil portion 303 is prevented. In this state, the first lead portions 37a and 37b can be pulled out in a direction away from the coil 300. That is, in the present embodiment, as shown in FIG. 7B, the terminal block 22 has a passage partitioned (or sandwiched) by the side wall portion 221, the pair of locking portions 222, and the separation convex portion 223. The first lead portions 37a and 37b can be pulled out from the bobbin 20 through these passages.

  Further, as shown in FIG. 4, in the pair of locking portions 232, the second lead portions 38a and 38b raised in the Z-axis direction by the rising portions 381a and 381b are replaced with Y at the portions of the direction changing portions 382a and 382b. It is wound from the inner side to the outer side in the axial direction, and is guided to the outer side in the X-axis direction with the gap between the drawer main body portions 383a and 383b being increased. The terminal block 23 does not need to be provided with a member similar to the separation protrusion 223 provided on the terminal block 22.

  The direction change portions 382a and 382b of the second lead portions 38a and 38b are locked to the pair of locking portions 232, so that the second lead portions 38a and 38b are configured by a common wire 38 positioned between the second lead portions 38a and 38b shown in FIG. 8A. The second lead portions 38a and 38b can be pulled away from the coil 300 in a state where the unwinding of the first coil portion 301 and the second coil portion 302 is prevented. That is, in this embodiment, as shown in FIG. 7A, the terminal block 23 is formed with a passage partitioned (or sandwiched) by the side wall portion 231 and the pair of locking portions 232, Through these passages, the second lead portions 38 a and 38 b can be pulled out in a direction away from the bobbin 20.

  As shown in FIG. 2, a lead wire cover 60 is attached to cover the terminal blocks 22 and 23 in the Z-axis direction. More specifically, holes 61 are formed in the side surfaces at both ends in the Y-axis direction of the lead wire cover 60, and the holes 61 are engaged with the engaging protrusions 224 and 234 formed in the terminal blocks 22 and 23. By combining, the lead wire cover 60 can be attached to the terminal blocks 22 and 23. Accordingly, it is possible to prevent the first lead portions 37a and 37b and the second lead portions 38a and 38b from protruding unnecessarily above the terminal blocks 22 and 23.

  In the present embodiment, the magnetic cores 40a and 40b have the same shape, and have an E-shaped cross section in the ZY cross section, forming a so-called E-type core. The mode of the magnetic cores 40a and 40b is not limited to the mode shown in FIG. 2, and the magnetic cores 40a and 40b are parallel to the XZ plane along the alternate long and short dash line (substantially central position in the Y-axis direction) A split core formed by cutting may be used.

  The magnetic core 40a disposed on the upper side in the Z-axis direction includes a base portion 44a extending in the Y-axis direction, a pair of side leg portions 48a projecting in the Z-axis direction from both ends in the Y-axis direction of the base portion 44a, and these Middle leg portion 46a protruding in the Z-axis direction from the center in the Y-axis direction. The magnetic core 40b disposed on the lower side in the Z-axis direction includes a base portion 44b extending in the Y-axis direction, a pair of side legs 48b protruding in the Z-axis direction from both ends in the Y-axis direction of the base portion 44b, Between these side leg parts 48b, it has the middle leg part 46b which protrudes in the Z-axis direction from the center of the Y-axis direction.

  The middle leg portion 46a is inserted into the core leg through hole 21a of the bobbin 20 from above in the Z-axis direction. Similarly, the middle leg portion 46b is inserted into the core leg through hole 21a of the bobbin 20 from below in the Z-axis direction, and in the core leg through hole 21a, the tip thereof has a predetermined gap G ( (See FIG. 5 and FIG. 6A).

  In this way, by forming the gap G, the leakage characteristics can be adjusted according to the width of the gap G. In addition, you may comprise so that the front-end | tip of the middle leg part 46b may contact the front-end | tip of the middle leg part 46a in the inside of the core leg through-hole 21a, without forming the gap G.

  The middle leg portion 46a and the middle leg portion 46b have a substantially elliptical column shape so as to coincide with the inner peripheral surface shape of the core leg through hole 21a. You may change according to the shape of the through-hole 21a for use. Moreover, the side leg parts 48a and 48b have an inner concave curved surface shape matched with the outer peripheral surface shape of the bobbin main body 21, and the outer surface has a plane parallel to the XZ plane. In the present embodiment, the materials of the cores 40a and 40b include soft magnetic materials such as metal and ferrite, but are not particularly limited.

  Covers 50 are arranged between the inner peripheral surfaces of the side legs 48a and 48b and the outer peripheral surface of the bobbin main body 21, respectively. The cover main body 52 of the cover 50 has a shape that covers the outer periphery of the bobbin main body 21 located between the terminal blocks 22 and 23 in the bobbin 20. At both ends in the Z-axis direction of the cover main body 52, locking pieces 54 bent in a substantially vertical direction from the cover main body 52 toward the bobbin main body 21 are integrally formed. A pair of locking pieces 54 formed on both sides in the Z-axis direction of the cover body 52 are attached so as to sandwich the upper and lower surfaces of the bobbin body 21 in the Z-axis direction, as shown in FIG.

  Further, side leg guide pieces 56 extending in the Z-axis direction are integrally formed on the outer surfaces of both ends in the X-axis direction of the cover body 52. The outer surface of the cover main body 52 located between the pair of side leg guide pieces 56 is in contact with the inner surfaces of the side legs 48a and 48b, and the movement of the side legs 48a and 48b in the X-axis direction causes the pair of side legs 48a and 48b to move. The guide piece 56 is limited. These covers 50 are made of an insulating member such as plastic or metal similar to the bobbin 20.

  As shown in FIG. 5, at the both ends in the Z-axis direction of the wound tube portion 28 constituting the bobbin body 21 of the bobbin 20, the end partition walls 24 and 25 extend radially outward so as to extend in the XY plane. Are integrally molded substantially in parallel with each other. Predetermined in the Z-axis direction so that the winding partition walls 26 and 27 protrude radially outward on the outer peripheral surface of the winding tube portion 28 located between the end partition walls 24 and 25 in the Z-axis direction. It is formed at intervals. Due to the winding partition walls 26 and 27 formed between these end partition walls 24 and 25, sections S1 to S3 are formed between these partition walls in order from the bottom in the Z-axis direction. The numbers of the winding partition walls 26 and 27 and the sections S1 to S3 are not particularly limited.

  In the present embodiment, the common wire 38 is continuously wound around the sections S1 and S3 by six turns to form the first coil section 301 and the second coil section 302, and the intermediate wire 37 is formed in the section S2. The third coil unit 303 is configured by winding in one turn. In the present embodiment, the wound partition wall 26 serves to partition the first coil part 301 and the intermediate coil part 303 in the Z-axis direction, and the wound partition wall 27 serves as the second coil part 302 and the intermediate coil part 303. And plays a role of partitioning in the Z-axis direction.

  As shown in FIG. 5, the section width T1 along the Z-axis in the sections S1 and S3 around which the common wire 38 constituting the first coil portion 301 is wound is such that one common wire 38 is in the Z-axis direction. It is set to a width that can be entered. However, the partition width T1 may be set to a width that allows two or more common wires 38 to enter in the Z-axis direction. In the present embodiment, the partition widths T1 are preferably all the same, but may be slightly different.

  The section width T2 along the Z axis in the section S2 around which the intermediate wire 37 constituting the intermediate coil section 303 is wound is set to a width that allows one intermediate wire 37 to enter in the Z axis direction. However, the partition width T2 may be set to a width that allows two or more intermediate wires 37 to enter in the Z-axis direction. In the present embodiment, the section width T2 along the Z axis in the section S2 is preferably different from the section width T1 according to the wire diameter of the common wire 38, but may be the same.

  Moreover, the height (length in the radial direction with respect to the winding axis) H1 of the partition walls 24 to 27 is set to a height at which one or more (one or more layers) wires 37 or 38 can enter. In the form, it is preferably set to a height at which 3 to 8 layers of wire can be wound. The heights H1 of the partition walls 24 to 27 are preferably all the same, but may be different.

  In the present embodiment, the winding method of the common wire 38 wound around the sections S1 and S3 is α winding, and the common wire 38 is connected to the sections S1 and S3 shown in FIG. 38 is passed through and started to be wound, and pulled out to the respective lead portions 38a and 38b shown in FIG. 8A. The winding method of the intermediate wire 37 wound around the section S2 shown in FIG. 5 is not particularly limited, and normal winding or α winding may be used.

  Here, the α winding will be described. For example, in order to α-wind the common wire 38 around the bobbin 20 shown in FIGS. 6A and 6B, first, the coil of the common wire 38 is formed in a portion where the circumferential portions of the winding partition walls 26 and 27 are notched. The section S1 and the section S3 shown in FIG. Then, a part of the common wire 38 on the side close to the lead portion 38a is wound in a plurality of layers (in this embodiment, six layers) around the outer periphery of the winding tube portion 28, for example, clockwise within the section S3. . At the same time, the other part of the common wire 38 on the side close to the lead portion 38b is disposed inside the section S1 in the direction opposite to the winding method in the section S1 (or in the same direction). Wind around the outer periphery in multiple layers. These operations may be performed using an automatic winding machine.

  As shown in FIG. 6A, the intermediate wire 37 wound around the section S2 shown in FIG. 5 is provided between the coils of the common wire 38 at the part where the circumferential portions of the winding partition walls 26 and 27 are cut away. After disposing the connecting portion 380, the first insulating cover 81 is attached, and thereafter, the winding is wound more than once between the winding partition walls 26 and 27 as shown in FIG.

  As shown in FIGS. 6A and 7A, bobbin leg portions 29 are integrally formed at both ends in the X-axis direction of the end partition ribs 25 located at the lowest part in the Z-axis direction. Each bobbin leg portion 29 is formed so as to protrude downward in the Z-axis direction from both ends of the end partition wall 25 in the X-axis direction. Each bobbin leg portion 29 accommodates each pedestal 70 shown in FIG. The height of each pedestal 70 in the Z-axis direction is adjusted so that the bottom surface of each pedestal 70 is substantially flush with the bottom surface of the core member 40b when each pedestal 70 is accommodated in each bobbin leg portion 29. . That is, the pedestal 70 also has a function as a height adjustment mechanism.

  As shown in FIG. 7A, notches 264 and 274 are formed on the terminal block 23 side of the winding partition walls 26 and 27 with a width narrower than the width in the Y-axis direction of the first insulating cover 81 shown in FIG. 7C. It is. Further, a counterbore surface 261 that does not penetrate in the Z-axis direction is formed on the lower surface of the winding partition wall 26 in the Z-axis direction at a circumferential position where the notch 264 is formed. Further, a counterbore surface 271 that does not penetrate in the Z-axis direction is formed on the upper surface in the Z-axis direction of the winding partition wall 27 at a circumferential position where the notch 274 is formed.

  A first insulating cover 81 shown in FIG. 7C is attached between the wound partition walls 26 and 27 along the counterbore surfaces 261 and 271 so as to close the notches 264 and 274. As shown in FIG. 7C, the first insulating cover 81 is for insulating the inter-coil connection portion 380 from the intermediate coil portion 303. As shown in FIG. 7A, a lead locking groove 272 is formed in the counterbore surface 271. The lead locking groove 272 is locked at the base end of the raised portion 381b of the second lead portion 38b, so that the raised portion 381b can be easily formed.

  As shown in FIG. 7C, the first insulating cover 81 includes an intermediate partial cylinder 813 that constitutes a part of a cylinder, partial flanges 811 that are formed in parallel on the XY axis plane at both ends in the Z-axis direction, and 812. In the intermediate partial cylinder 813, a part in the circumferential direction of the intermediate wire 37 constituting the intermediate coil portion 303 is wound. As shown in FIG. 6A, the inner peripheral surface of the intermediate partial cylinder 813 faces the outer peripheral surface of the wound cylinder portion 28 of the bobbin 20 with the inter-coil connection portion 380 interposed therebetween.

  The first insulating cover 81 has one partial flange 811 in contact with the counterbore surface 261 of the winding partition wall portion 26 and the other partial flange 812 in contact with the counterbore surface 271 of the winding partition wall portion 27 so that sliding insertion is possible. The bobbin 20 is fixed. As shown in FIG. 9, in this embodiment, the inter-coil connection portion 380 passes through the inside of the intermediate coil portion 303, but as shown in FIG. 7C, the inter-coil connection portion 380 and the intermediate coil portion 303 are intermediate. It is insulated via the partial cylinder 813.

  As shown in FIG. 6A, notches 244 and 264 are formed on the terminal block 22 side of the end partition wall 24 and the winding partition wall 26 so that the second insulating cover 82 shown in FIG. 7D can be attached. is there. As shown in FIG. 8B, the second insulating cover 82 is for insulating the upright portions 371a and 371b of the first lead portions 37a and 37b and the direction changing portions 372a and 372b from the first coil portion 301. .

  As shown in FIG. 7D, the second insulating cover 82 is composed of parts ridges 821 and 822 formed in parallel on the XY axis plane at both ends in the Z-axis direction, a wall part 823, and a pair of side parts 824. And have. Convex portions 825 are formed on the outer surfaces of the side portions 824 in the Y-axis direction. As shown in FIG. 6A, in the second insulating cover 82, one partial flange 821 is fitted into the groove formed in the end partition wall 24, and the other partial flange 822 is brought into contact with the counterbore surface of the wound partition wall 26. It is fixed to the bobbin 20 by sliding it in contact.

  At this time, as shown in FIG. 7B, the convex portion 825 formed on the second insulating cover 82 has the Y-axis direction end portion of the winding partition wall 26 and the Y-axis direction end portion ( The second insulating cover 82 is stably fixed to the bobbin 20. As shown in FIGS. 8B and 8C, the rising portions 371 a and 371 b of the first lead portions 37 a and 37 b and the first coil portion 301 are well insulated via the second insulating cover 82. As shown in FIG. 7B, the winding partition wall 27 has a protruding portion that protrudes outward in the X-axis direction (in the direction away from the winding axis of the bobbin 20). The insulation between the wire 37 and the first lead portions 37a and 37b thereof and the second coil portion 302 is also kept good.

  These insulating covers 81 and 82 are made of an insulating member such as plastic similar to or different from the bobbin 20. The insulating covers 81 and 82 are formed separately from the bobbin 20 and attached to a part of the bobbin 20 in the circumferential direction.

  The transformer 10 according to the present embodiment is manufactured by assembling the members shown in FIG. 2 and winding the intermediate wire 37 and the common wire 38 around the bobbin 20. Hereinafter, an example of a method for manufacturing the transformer 10 will be described with reference to FIG. In manufacturing the transformer 10, first, the bobbin 20 is prepared. The material of the bobbin 20 is not particularly limited, but the bobbin 20 is formed of an insulating material such as resin.

  Next, the common wire 38 is wound around the outer periphery of the winding tube portion 28 of the bobbin 20 by α winding to form the first coil portion 301 and the second coil portion 302. Although it does not specifically limit as the common wire 38 used for formation of the 1st coil part 301 and the 2nd coil part 302, A litz wire etc. are used suitably. Also, the second lead portions 38a and 38b, which are the end portions of the common wire 38 when forming the first coil portion 301 and the second coil portion 302, are connected to the terminal 94 by soldering, for example.

  Next, the first insulating cover 81 and the second insulating cover 82 are attached to the bobbin 20 around which the common wire 38 is wound. The second insulating cover 82 may be attached to the bobbin 20 later, and at least the first insulating cover 81 may be attached to the bobbin 20.

  Next, the intermediate wire 37 is wound around the outer periphery of the winding tube portion 28 of the bobbin 20 to form the intermediate coil portion 303. The intermediate wire 38 used for forming the intermediate coil portion 303 may be the same as or different from the common wire 38. In addition, the first lead portions 37a and 37b, which are the end portions of the intermediate wire 37 when forming the intermediate coil portion 303, are connected to the terminal 94 by soldering, for example.

  Next, the first lead portions 37 a and 37 b are pulled out from the intermediate coil portion 303 above the winding axis, and are pulled out in a direction away from the coil 300 while being locked by the locking portion 222. At that time, a second insulating cover 82 is attached to the bobbin 20 in advance.

  Further, the second lead portions 38 a and 38 b are pulled out from the first coil portion 301 and the second coil portion 302 to the upper side of the winding axis, and pulled out in a direction away from the coil 300 while being locked to the locking portions 222 and 232. Then, the lead wire cover 60 is mounted above the terminal blocks 22 and 23.

  Next, the cover 50 is attached to both sides of the bobbin 20 in the Y-axis direction, and then the magnetic cores 40a and 40b are attached from the vertical direction in the Z-axis direction. That is, the tips of the side legs 48a and 48b are joined to each other while the gap G is provided between the tips of the middle legs 46a and 46b of the magnetic cores 40a and 40b. Examples of the material of the magnetic cores 40a and 40b include soft magnetic materials such as metal and ferrite, but are not particularly limited. The gap G may be zero.

  Next, the base 70 is accommodated in the bobbin leg portion 29. A pedestal 70 may be attached to the bobbin leg 29 in advance. Thereafter, the bottom plate 92 is bonded to the bottom opening of the case 90, and the assembly is housed in the case 90 having an open top, and the case 90 is filled with a heat radiation resin. Through the steps as described above, the transformer 10 according to the present embodiment can be manufactured.

  The transformer 10 according to the present embodiment has a structure (sandwich structure) in which the intermediate coil portion 303 is sandwiched between the first coil portion 301 and the second coil portion 302. Therefore, the coupling between these coil portions can be increased, and it becomes easy to stabilize the leakage characteristics. In addition, a highly coupled transformer 10 capable of obtaining stable leakage characteristics even in a high frequency band can be realized.

  Further, the first coil portion 301 and the second coil portion 302 are continuously formed by the common wire 38. By adopting such a configuration, it is possible to prevent current from flowing in one of the first coil portion 301 and the second coil portion 302 in an uneven manner. Since the current is prevented from flowing unevenly, it is possible to prevent any one of the coil portions 301 or 302 from abnormally generating heat. Moreover, compared with the case where the 1st coil part 301 and the 2nd coil part 302 are comprised with a separate wire, the wire length of the common wire 38 which comprises the 1st coil part 301 and the 2nd coil part 302 is shortened. Thus, the copper loss can be reduced. If the copper loss can be reduced, efficiency can be improved and heat generation can be reduced.

  Further, in this embodiment, since the coupling coefficient between the primary coil and the secondary coil is high, the leakage characteristics are stabilized even when the number of turns of the primary coil and the number of turns of the secondary coil are greatly different. Is easy. That is, according to the present embodiment, the effect is great even when the turn ratio between the number of turns of the common wire 38 in the first coil part 301 and the second coil part 302 and the number of turns of the intermediate wire 37 in the intermediate coil part 303 is large. Specifically, even when the turn ratio n1 / n2 between the total number of turns n1 of the common wire 38 and the number of turns n2 of the intermediate wire 37 is 2 or more, 3 or more, 5 or more, a more remarkable effect can be obtained.

  In the present embodiment, the common wire 38 is α-wound around the bobbin 20. By setting it as such a structure, the 1st coil part 301 and the 2nd coil part 302 which are spaced apart in the winding axis direction can be easily formed using the single common wire 38. Moreover, it is easy to make the number of turns of the coil the same in the first coil part 301 and the second coil part 302, and it is also easy to change the number of turns.

  Furthermore, as shown in FIG. 5, in each of the first coil portion 301 and the second coil portion 302, the flange portions 24 to 27 of the bobbin 20 have only a single wire 38 along the winding axis direction. By adjusting the intervals T1 and T2, it becomes easy to prevent variations in the number of turns of the wires 37 and 38 per layer, and contribute to stabilization of the leakage characteristics. That is, it becomes easy to strictly control the coupling coefficient between the primary coil and the secondary coil.

  Further, the α winding contributes to a reduction in the height and size of the coil device 10 because the number of layers in the winding axis direction can be reduced even if the number of turns is increased. Furthermore, since the wire is not drawn out from the center of the winding by using α winding, the wires do not overlap each other, which contributes to a reduction in the height of the coil device 10.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, as another aspect in which the coil 300 is mounted on the outer periphery of the bobbin 20, the intermediate wire 37 is first wound around the bobbin 20 to form the intermediate coil portion 303, and then the common wire 38 is wound around the bobbin 20. An aspect in which the first coil unit 301 and the second coil unit 302 are configured is also conceivable. When the coil 300 is mounted on the bobbin 20 in such a manner, the inter-coil connection portion 380 passes outside the intermediate coil portion 303.

  Further, the relationship between the primary coil and the secondary coil described above may be reversed. That is, the common wire 38 may constitute a secondary coil, and the intermediate wire 37 may constitute a primary coil. In that case, the magnitude relationship of the outer diameter of each wire may be opposite to the above-described example. Alternatively, the outer diameters of these wires may be the same.

DESCRIPTION OF SYMBOLS 10 ... Transformer 20 ... Bobbin 21 ... Bobbin main body 21a ... Core leg through-hole 22, 23 ... Terminal block 221, 231 ... Side wall part 222, 222 ... Locking part 223 ... Separation convex part 224, 234 ... Engaging protrusion part 24 , 25 ... End partition wall 244 ... Notch portion 26, 27 ... Winding partition wall rod 261, 271 ... Counterbore surface 272 ... Lead locking groove 264, 274 ... Notch portion 28 ... Winding tube portion 29 ... Bobbin leg portion 300 ... Coil part 301 ... 1st coil part 302 ... 2nd coil part 303 ... Intermediate coil part 37 ... Intermediate wire 37a, 37b ... 1st lead part 371a, 371b ... Upright part 372a, 372b ... Direction change part 373a, 373b ... Drawer main body Part 38 ... Common wire 38a, 38b ... Second lead part 381a, 381b ... Rising part 382a, 382b ... Direction changing part 383a, 383b Drawer main body 380... Inter-coil connection portion 40 a, 40 b... Magnetic core 44 a, 44 b... Base portion 46 a, 46 b ... Middle leg portion 48 a, 48 b ... Side leg portion 50 ... Cover 52 ... Cover main body portion 54. Side leg guide piece 60 ... Drawer wire cover 70 ... Base 81 ... First insulating cover 811, 812 ... Partial flange 813 ... Intermediate partial cylinder 82 ... Second insulating cover 821, 822 ... Partial flange 823 ... Wall portion 824 ... Side portion 825 ... convex part 90 ... case 91 ... boss part 92 ... bottom plate 94 ... terminal

Claims (8)

A first coil part;
A second coil part, which is made of the same common wire as the wire constituting the first coil part, and is arranged away from the first coil part along a winding axis;
A coil device having an intermediate coil portion that is located between the first coil portion and the second coil portion along the winding axis and is configured by an intermediate wire different from the common wire.   The coil device according to claim 1, wherein the common wire is α-wound around a bobbin.   The coil device according to claim 1 or 2, wherein the number of turns of the common wire in the first coil part and the second coil part is different from the number of turns of the intermediate wire in the intermediate coil part.   The coil according to any one of claims 1 to 3, wherein the common wire has an inter-coil connection portion extending in the winding axis direction between the first coil portion and the second coil portion. apparatus.   The coil device according to claim 4, wherein the inter-coil connection portion passes inside the intermediate coil portion.   The coil device according to claim 4 or 5, further comprising a first insulating cover for insulating the inter-coil connecting portion from the intermediate coil portion. The lead portion of the intermediate wire has a raised portion extending in the winding axis direction;
The coil device according to any one of claims 1 to 6, further comprising a second insulating cover for insulating the upright portion from the first coil portion.   The said common wire comprises any one of a primary coil or a secondary coil, and the said intermediate wire comprises any one of a primary coil or a secondary coil, The 1st characterized by the above-mentioned. The coil device according to any one of 7.

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