CN111540587A - Coil device - Google Patents

Abstract

The invention provides a coil device which can realize miniaturization of the coil device and has excellent heat dissipation performance. A coil device (10) is provided with: a bobbin (40) having a first winding portion (45) around the outer periphery of which a first wire (22) is wound; and a bobbin case (50) that covers the periphery of the bobbin (40) around which the first wire (22) is wound. The bobbin case (50) has: a second winding part (55) on the outer periphery of which a second wire (32) different from the first wire (22) is wound, and a non-winding part (57) provided at a lower position of the second winding part (55) along the axial direction. The non-winding portion (57) has an opening (57b) or a notch (57c) that allows the inside and the outside of the bobbin case (50) to communicate with each other.

Description

Coil device

Technical Field

The present invention relates to a coil device that can also be preferably used as, for example, a transformer.

Background

For example, a coil device shown in patent document 1 is known as a coil device used for a transformer or the like. In this conventional coil device, the coil located inside is wound around the outer peripheral surface of the bobbin disposed inside, the periphery of the coil is surrounded by the bobbin case, and the coil located outside is wound around the outer peripheral surface of the bobbin.

In order to provide good coupling between the outer coil and the inner coil, the gap between the bobbin and the bobbin case is typically small. The bobbin case is generally disposed so as to cover the entire coil located inside.

In recent years, heat generation of coil devices has become a problem with miniaturization of coil devices. Therefore, a coil device is designed to be impregnated with potting resin to improve heat dissipation and the like. However, recently, further miniaturization of the coil device has been demanded, and the conventional coil device has a problem that heat generated by the inner coil cannot be efficiently dissipated.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2014-93404

Disclosure of Invention

Problems to be solved by the invention

The present invention has been made in view of such a situation, and an object thereof is to provide a coil device which can be downsized and has excellent heat dissipation.

Means for solving the problems

In order to achieve the above object, a coil device of the present invention includes:

a bobbin having a first winding portion around which a first wire is wound on an outer periphery thereof; and

a bobbin case covering a periphery of a bobbin around which the first wire is wound, wherein,

the bobbin case has: a second wound portion around which a second cord different from the first cord is wound on an outer periphery thereof, a non-wound portion provided at a position below the second wound portion in an axial direction thereof,

the non-winding portion has an opening or a notch portion that communicates the inside and the outside of the bobbin case.

In the coil device of the present invention, the bobbin case has a non-winding portion, and the non-winding portion has an opening or a notch. Therefore, the heat dissipating resin such as potting resin enters the inside of the bobbin case through the opening or the notch and enters between the bobbin case and the bobbin. As a result, the first wire wound around the first winding portion of the bobbin comes into contact with the heat dissipating resin, and heat generated from the first wire is transmitted to the heat dissipating resin to be dissipated. Therefore, in the coil device of the present invention, heat dissipation is excellent even if the coil device is downsized.

In the coil device of the present invention, since the bobbin case has the non-winding portion, the axial positions of the inner coil formed of the first wire and the outer coil formed of the second wire are easily shifted. Therefore, the magnetic flux leakage characteristic of the coil device is easily adjusted. Further, since a part of the inner coil formed of the first wire can be exposed to the outside of the bobbin case through the opening or the cutout formed in the non-winding portion, the heat radiation performance is improved in this point.

The size of the opening or the notch is preferably a size of a degree that the heat dissipating resin located outside the bobbin case can smoothly enter the inside of the bobbin case. With this configuration, the heat dissipating resin easily enters the inside of the bobbin case.

The bobbin may have a bobbin base plate and a bobbin upper flange portion, and the first winding portion may be formed between the two bobbin base plates and the bobbin upper flange portion. The bottom surface of the non-winding portion is preferably disposed on the bobbin base plate. With this configuration, the bobbin case can be easily attached to the bobbin.

The bobbin case may have a case lower flange portion and a case upper flange portion, and the non-winding portion may be provided below the case lower flange portion. Preferably, the cover upper flange portion is disposed axially below the bobbin upper flange portion, and an outlet gap through which air inside the bobbin cover can be discharged to the outside is formed between the bobbin upper flange portion and the cover upper flange portion.

With this configuration, when the heat dissipating resin enters the interior of the bobbin case from the opening or the notch of the non-winding portion, the air in the interior of the bobbin case is easily discharged from the outlet gap, and the heat dissipating resin is smoothly filled.

The first winding portion may include a partition rib at predetermined intervals in the axial direction. In addition, a positioning convex portion for positioning in contact with the inner peripheral surface of the bobbin case may be formed in a part in the circumferential direction on any of the winding partition wall ribs. Preferably, a flow gap through which the heat dissipating resin flows is formed between an outer peripheral surface of the winding partition rib and an inner peripheral surface of the bobbin case, in addition to the positioning projection. The heat dissipating resin can be filled in the bobbin case over the entire circumference of the bobbin by flowing through the flow gap.

The bobbin case is preferably formed of a pair of half-divided bodies having divided connecting portions. Further, it is preferable that the positioning protrusion is formed so as to contact with an inner side of the divided connecting portion. With this configuration, the strength of the divided connection portions can be increased, and uniform flow gaps can be easily formed in the circumferential direction.

Drawings

Fig. 1 is a perspective view of a coil device according to an embodiment of the present invention.

Fig. 2A is an exploded perspective view of the coil device shown in fig. 1.

Fig. 2B is a perspective view of the bobbin after disassembling the bobbin case shown in fig. 2A.

Fig. 2C is a perspective view of the bobbin after disassembling the bobbin case, viewed from a different angle from fig. 2B.

Fig. 3 is a perspective view for winding a first wire on the bobbin shown in fig. 2B.

Fig. 4 is a side view of the coil device shown in fig. 1 viewed from the right side along the X-axis.

Fig. 5 is a side view of the coil device shown in fig. 1 viewed from the left side along the X-axis.

Fig. 6A is a main part sectional view taken along the VIA-VIA line shown in fig. 1.

Fig. 6B is a main portion sectional view taken along the VIB-VIB line shown in fig. 1.

Detailed Description

The present invention will be described below based on embodiments shown in the drawings.

As shown in fig. 1, a coil device 10 according to an embodiment of the present invention includes: four magnetic cores 12, a bobbin 40, a bobbin case 50, and two core cases 60. In the present embodiment, in the drawing, the X axis, the Y axis, and the Z axis are perpendicular to each other, the direction perpendicular to the mounting surface of the coil device 10 is the Z axis, and the direction in which the pair of lead drawing portions 49 formed on the bobbin 40 are located on the opposite side to each other is the X axis.

As shown in fig. 2A, the four magnetic cores 12 are assembled to form a magnetic path through which magnetic flux generated by a coil described later passes. The four magnetic cores 12 have a symmetrical shape, and are connected to each other so as to sandwich the bobbin case 50 and the bobbin 40 from the vertical direction (in the figure, the Z-axis direction).

Each of the magnetic cores 12 has a substantially E-shaped longitudinal section (a section including the Y-axis and the Z-axis). Each of the magnetic cores 12 is made of a soft magnetic material such as ferrite or a metal magnetic material, and includes: a flat plate-shaped base portion 13 extending in the Y-axis direction, a pair of side legs 16, 16 projecting in the Z-axis direction from both ends in the Y-axis direction of each base portion 13, and a center leg 14 projecting in the Z-axis direction from a middle position in the Y-axis direction of each base portion 13.

In the present embodiment, the center leg 14 of each magnetic core 12 enters the inside of the first through hole 44a formed in the first hollow tube portion 44 of the bobbin 40. The magnetic cores 12, 12 adjacent in the X-axis direction form a gap therebetween by the separation convex portion 44b formed on the inner peripheral wall of the first hollow cylindrical portion 44. When a heat dissipating resin such as potting resin described later enters the gap, heat dissipation of heat generated inside the coil device 10 is improved.

The gap formed by the separation projection 44b corresponds to the thickness of the separation projection 44b in the X-axis direction. The separating protrusions 44b are formed inside the through hole 44a at the center in the X axis direction on both sides in the Y axis direction along the Z axis. The thickness of the separating projection 44b in the X-axis direction is not particularly limited, but is preferably 0.05 to 5mm, and more preferably 0.1 to 3 mm.

As shown in fig. 2B, the bobbin 40 has a bobbin base plate 42 of a substantially elliptical flat plate shape at a lower end portion in the Z-axis direction thereof. As shown in fig. 3, a first hollow tube 44 is integrally formed in a substantially central portion of the bobbin base plate 42 so as to extend to an upper portion in the Z-axis direction.

As shown in fig. 3, a bobbin upper flange portion 48 is integrally formed on the Z-axis direction upper portion of the first hollow tube portion 44 so as to radially project from the first hollow tube portion 44 on the Y-X axis plane. Lead drawing portions 49 are integrally formed on both ends of the bobbin flange portion 48 in the X axis direction, respectively. The lead drawing portion 49 may be formed separately from the bobbin 40 and then joined to the bobbin upper flange portion 48 of the bobbin 40 by fitting, bonding, or the like.

As shown in fig. 2B, one lead drawing portion 49 has a base 49c formed with a pair of vertical drawing grooves 49a, and the pair of vertical drawing grooves 49a draw out a pair of lead portions 22a, which are both end portions of the first wire 22 constituting the inner coil 20, upward in the Z axis, respectively. The base 49c is formed with a horizontal lead-out groove 49b led out to the opposite side of the Y-axis direction at the upper part of the vertical lead-out groove 49a in the Z-axis direction. The lead portions 22a and 22a are guided in the horizontal lead grooves 49 b. Terminals, not shown, are connected to the distal ends of the lead portions 22a, 22 a. The terminals may be embedded in the base 49c and integrated.

The other lead drawing portion 49 shown in fig. 2B has a base 49c formed with a pair of vertical drawing grooves 49a, and the pair of vertical drawing grooves 49a draw out a pair of lead portions 32a, which are both end portions of the second wire 32 constituting the outer coil 30, upward in the Z axis, respectively. The base 49c is formed with a horizontal lead-out groove 49b led out to the opposite side of the Y-axis direction at the upper part of the vertical lead-out groove 49a in the Z-axis direction. The lead portions 32a and 32a are guided in the horizontal lead grooves 49 b. Terminals, not shown, are connected to the distal ends of the lead portions 32a and 32 a. The terminals may be embedded in the base 49c and integrated.

Further, an insulating wall 49d rising upward in the Z axis from the boundary between the base 49c and the first hollow tube 44 is formed in each lead drawing portion 49. The insulating wall 49d can increase the insulating distance between the lead portion 22a or 32a and the magnetic cores 12, 12 shown in fig. 1.

As shown in fig. 3, a first winding portion 45 is formed on the outer peripheral portion of the first hollow tube portion 44 located between the bobbin upper flange portion 48 and the bobbin base plate 42. In the first winding portion 45, as shown in fig. 6B, a plurality of winding partition ribs 46 separate mutually adjacent wire winding portions of the first wire 22 along the winding axis (Z axis) from each other, and the plurality of winding partition ribs 46 are formed integrally with the first hollow cylindrical portion 44 at predetermined intervals along the winding axis and substantially in parallel with the bobbin base plate 42 (and the bobbin upper flange portion 48). The details of winding the partition wall rib 46 and the winding method of the first cord 22 will be described later.

The bobbin base plate 42, the first hollow cylindrical portion 44, the bobbin upper flange portion 48, the lead draw-out portion 49, and the winding partition rib 46 of the bobbin 40 are preferably integrally formed by injection molding or the like.

A first through hole 44a penetrating in the Z-axis direction is formed in the first hollow tube portion 44 of the bobbin base plate 42. The center leg 14 of the magnetic core 12 enters the first through hole 44a from above and below in the Z-axis direction, and the tip of the center leg 14 abuts against the substantially central portion of the through hole 44a in the Z-axis direction. As shown in fig. 6B, the tip ends of the center legs 14 inserted from the top and bottom of the Z axis may be spaced apart from each other at a predetermined interval in the substantially central portion of the through hole 44a in the Z axis direction.

As shown in fig. 2B, the bobbin case 50 is composed of a pair of half-divided bodies 50a, 50B dividable into two in the X-axis direction, and is combined by a divided connecting portion 53 parallel to the winding axis (Z-axis), and in the combined state, a second winding portion 55 is formed on the outer peripheral portion of the case 50. The bobbin case 50 is assembled by winding the first wire 22 around the first winding portion 45 of the bobbin 40 to form the inner coil 20, and then attached to the outer periphery of the bobbin 40 and divided by the connecting portions 53.

The bobbin case 50 has a second hollow tube 54 covering the inner coil 20 from the outside, and a case lower flange portion 52 and a case upper flange portion 58 are formed in the outer peripheral portion of the second hollow tube 54 in the circumferential direction at a predetermined interval in the Z-axis direction. The lower flange portion 52 and the upper flange portion 58 are provided parallel to the plane of the X-Y axis and extend parallel to the installation plane.

Between the two lower flange portions 52 and the upper flange portion 58, a second winding portion 55 is formed, and the second cord 32 constituting the outer coil 30 as the secondary coil, for example, is wound in parallel (or α -wound) in the second winding portion 55. The aligned winding means a normal winding method in which a wire is wound from one end of a winding shaft to the other end. Regarding the α winding, description will be made later.

As shown in fig. 2A, a pair of core covers 60 are attached to the outer periphery of the second winding portion 55 of the bobbin case 50 to which the outer coil 30 is attached, from both sides in the Y-axis direction. The core cover 60 is made of an insulating member such as synthetic resin, and has a cover main body 62 whose outer peripheral surface serves as a guide surface for guiding the side legs 16 of the core 12 and whose inner peripheral surface the outer coil 30 is positioned.

Mounting rims 64, 64 are integrally formed at both ends of the cover main body 62 in the Z-axis direction. The upper mounting flange 64 of the Z axis is joined to the upper surface of the upper flange 48 of the bobbin, the lower mounting flange 64 of the Z axis is joined to the lower surface of the bobbin base plate 42, and the core cover 60 is attached to the bobbin 40.

The cover main body 62 has an inner peripheral surface shape corresponding to the outer peripheral surface shape of the core cover 60, and insulating plate portions 66 are integrally formed at both ends in the X-axis direction thereof. The insulating plate 66 has engaging projections 66a formed on the upper and lower sides in the Z-axis direction and projecting inward in the Y-axis direction. The upper Z-axis engaging projection 66a is engaged with the inner surface of the insulating wall 49d of the lead drawing portion 49, and the lower Z-axis engaging projection 66a is engaged with the inner surface of the leg portion 42a integrally formed downward in the Z-axis direction from both X-axis ends of the bobbin base plate 42.

As a result, as shown in fig. 1, the insulating plate portion 66 of the core cover 60 is combined with the insulating wall 49d and the leg portion 42a, thereby improving the insulation between the core 12 and the outer coil 30. The inner surface of the insulating plate portion 66 (the center side of the coil device 10) may be in contact with the magnetic core 12, or may have a shape conforming to the outer shape of the magnetic core 12.

As shown in fig. 3, in the present embodiment, an elliptical ring-shaped winding partition rib 46 is formed on a plane substantially parallel to the X-Y axis on the outer peripheral portion of a substantially elliptical cylinder-shaped first hollow cylinder portion 44 so as to form winding regions 47 at predetermined intervals along the Z-axis direction. In the present embodiment, a plurality of wound partition ribs 46 are formed substantially in parallel at predetermined intervals along the Z-axis direction, but the number thereof is not particularly limited. The area where these partition rib 46 is formed becomes the first wound portion 45.

The winding area width along the winding axis (Z axis) of each winding area 47 separated by the winding partition rib 46 is set to a width into which one thread 22 enters. That is, the winding region width w1 is preferably in the relationship of d1 < w1 < (2 × d1), more preferably d1 < w1 < (1.2 × d1), with respect to the wire diameter d1 of the wire 22. If the winding region width is too wide relative to the wire diameter d1, winding disturbances are likely to occur, and the requirement for compactness of the coil device is violated.

In each winding region 47, the winding region widths are preferably all the same, but may be slightly different. Further, the width of the winding area between the flange portion 48 on the bobbin and the winding partition rib 46 at the uppermost position may be larger than the width of the winding area between the winding partition ribs 46. Similarly, the width of the winding area between the bobbin base plate 42 and the winding partition rib 46 positioned at the lowermost position may be larger than the width of the winding area between the winding partition ribs 46. In the present embodiment, the predetermined total number of turns to be wound around each winding region 47 is not particularly limited.

As shown in fig. 2B, in the present embodiment, some of the winding partition ribs 46 are formed with positioning protrusions 46d for positioning in contact with the inner peripheral surface of the bobbin case 50 shown in fig. 2B in a part in the circumferential direction. As shown in fig. 6A, in the portion other than the positioning convex portion 46d, a flow gap 46e through which the heat-dissipating resin can flow is formed between the outer peripheral surface of the winding partition rib 46 and the inner peripheral surface of the bobbin case 50.

The positioning projection 46d preferably projects from the outer peripheral surface of the winding partition rib 46 at a position in contact with the inside of the divided connecting portion 53 of the bobbin case 50. The protruding height (radial height) of the positioning projection 46d defines the radial width of the flow gap 46e, and is preferably about 0.5 to 1 mm. This is to facilitate the flow of the heat dissipating resin and to improve the coupling between the coils 20 and 30.

As shown in fig. 2C, a positioning convex portion 48d similar to the positioning convex portion 46d of the winding partition rib 46 is preferably formed also on the lower surface of the upper flange portion 48 of the bobbin 40. The positioning protrusion 48d is also in contact with the inside of the divided connecting portion 53 of the bobbin case 50 to form the flow gap 46e, similarly to the positioning protrusion 46d shown in fig. 6A.

As shown in fig. 6A, the bobbin case 50 is configured such that the split coupling portions 53 of the bobbin case 50 are coupled to each other by inserting the outer coupling portions 53b of the other half-split body 50b radially outward of the inner coupling portions 53a of the one half-split body 50 a.

As shown in fig. 2B, the bobbin case 50 includes: a second wound portion 54 in which the second cord 32 different from the first cord 22 is wound around the outer periphery, and a non-wound portion 57 provided at a lower position in the axial direction of the second wound portion 54. The non-winding portion 57 has an opening portion 57b or a notch portion 57c that communicates the inside and the outside of the bobbin case 50.

The openings 57b are through holes in the areas of the cover lower flange portion 52, the posts 57d, and the lower beam 57e, are formed in the half-divided bodies 50a and 50b positioned on both sides in the X-axis direction, respectively, and are completely open to the outside of the coil device 10 as shown in fig. 1. The notch 57c shown in fig. 2B is an open space defined by the cover lower flange portion 52 and the column 57d, and serves as a hole communicating the outside and the inside of the bobbin cover 50 when the bottom surface 57a of the bobbin cover 50 is provided on the bobbin base plate 42 of the bobbin 40. As shown in fig. 1, a part of the notch 57c is not closed by the core cover 60, but is completely open to the outside of the coil device 10.

The size of the opening 57B or the notch 57c shown in fig. 2B is not particularly limited as long as the heat-dissipating resin such as potting resin located outside the bobbin case 50 can smoothly enter the inside of the bobbin case 50. The height of the opening 57b or the notch 57c in the axial direction is, for example, 1 to 5 mm. The circumferential length of the opening 57b or the notch 57c is, for example, about 15 to 20 mm.

A hook portion 53c is formed on the outer peripheral surface of the inner connecting portion 53a of the divided connecting portion 53 of the non-winding portion 57 of the one half-divided body 50 a. Further, a hook portion 53d is formed on the inner peripheral surface of the outer connecting portion 53b of the divided connecting portion 53 of the non-winding portion 57 of the other half-divided body 50b (see fig. 2C). These hook portions 53c and 53d are engaged when the engagement pieces 53a and 53b are connected to each other, and the connection of the connection portion 53 is not disengaged.

As shown in fig. 2B, a stepped upper flange portion 58a is formed above the other portion along the Z axis on the cover upper flange portion 58 of the one half segment 50a positioned at the connecting portion 53 a. Further, an upper flange portion 58b is formed on the cover upper flange portion 58 of the other half-divided body 50b positioned at the connection portion 53b, and the upper flange portion 58b is positioned below the upper flange portion 58a along the Z axis and is inserted and connected below the upper flange portion 58 a.

Further, a stopper projection 58i, which is brought into contact with the connection tip of the upper flange portion 58a, is formed on the cover upper flange portion 58 of the other half-divided body 50b, which is positioned at the connection portion 53 b. The stopper projection 58i projects upward in the Z-axis direction from most of the upper surface of the cover upper flange 58. The height of projection of the stopper projection 58i from most of the upper surface of the cover upper flange 58 is preferably substantially the same as the height of projection along the Z axis of the upper flange 58 a. The upper surfaces of the stopper convex portions 58i and the upper surface of the upper flange portion 58a contact the lower surface of the bobbin upper flange portion 48 of the bobbin 40, and an air outlet gap is formed between the upper surface of the cover upper flange portion 58 and the lower surface of the bobbin upper flange portion 48 in most portions other than the divided connecting portions 53.

The cover upper flange portion 58 located on the opposite side of the connection upper flange portion 58a along the X axis of the one half-divided body 50a is provided with a joining convex portion 58c protruding above the upper surface of the cover upper flange portion 58 along the Z axis. A joint surface 58e is formed on the upper surface of the joint convex portion 58c, and the projection height of the joint surface 58e along the Z axis with respect to the upper surface of the cover flange portion 58 is approximately the same as the step height of the connecting flange portion 58 a. The bonding surface 58e contacts the lower surface of the lead-out portion 49. The lower surface of the lead drawing portion 49 is substantially the same height as the lower surface of the flange portion 48 on the bobbin along the Z axis.

A positioning convex portion 59 protruding upward along the Z axis from the joint surface 58e is provided at the center of the joint surface 58e in the Y axis direction, and a positioning groove 59a is formed in the inner peripheral surface of the positioning convex portion 59. The engagement projection 49e of the lead drawing portion 49 provided at one end of the bobbin 40 in the X-axis direction is inserted into the positioning groove 59a, thereby positioning the bobbin case 50 in the circumferential direction with respect to the bobbin 40. The engagement projection 49e forms a part of a partition wall that partitions the pair of vertical lead-out grooves 49 a.

The cover upper flange portion 58 located on the opposite side of the upper flange portion 58b along the X axis of the other half-divided body 50b is provided with a joining convex portion 58d that protrudes above the upper surface of the cover upper flange portion 58 along the Z axis. A joint surface 58f is formed on the upper surface of the joint convex portion 58d, and the height of the joint surface 58f protruding from the upper surface of the cover upper flange portion 58 along the Z axis is approximately the same as the height of the stopper convex portion 58 i. The bonding surface 58f contacts the lower surface of the lead-out portion 49. The lower surface of the lead drawing portion 49 is substantially the same height as the lower surface of the flange portion 48 on the bobbin along the Z axis.

A positioning groove 59a is formed in the center of the joint surface 58f in the Y axis direction on the inner peripheral surface thereof. The engagement projection 49e (see fig. 3) of the lead drawing portion 49 provided at the other end of the bobbin 40 in the X-axis direction is inserted into the positioning groove 59a, thereby positioning the bobbin case 50 in the circumferential direction with respect to the bobbin 40. The engagement projection 49e forms a part of a partition wall that partitions the pair of vertical lead-out grooves 49 a.

The first wire 22 shown in fig. 2B may be composed of a single wire or may be composed of a stranded wire, preferably an insulated covered wire. The outer diameter d1 of the first wire 22 is not particularly limited, but is preferably, for example, 1.0 to 3.0mm when a large current is applied. The second line 32 may also be the same as the first line 22, but may also be different.

In this embodiment, the inner coil 20 formed of the first wire 22 shown in fig. 2B constitutes a primary coil of the transformer, and the outer coil 30 formed of the second wire 32 wound around the bobbin case 50 constitutes a secondary coil. Therefore, in the present embodiment, as shown in fig. 6B, the second wire 32 constituting the outer coil 30 has a larger wire diameter than the first wire 22, but the wire diameter is not particularly limited, and may be the same, or may be different. The materials of the first wire 22 and the second wire 32 may be the same or different.

As shown in fig. 3, in the bobbin 40 of the present embodiment, at least one communication groove 46a for communicating adjacent winding regions 47 is formed in each winding partition rib 46. In the present embodiment, the circumferential position of at least one of the pair of notch edges 46b, 46c formed in the winding partition rib 46 so as to define the circumferential width of the respective communication groove 46a is the same position as the position of the winding partition rib 46 adjacent in the Z-axis direction (reel), but may be different positions. The circumferential direction is a direction along the elliptical outer peripheral surface of the hollow cylindrical portion 44.

As shown in fig. 3, in the bobbin 40 of the present embodiment, the first wire 22 is wound from, for example, the center portion in the Z-axis direction of the first wound portion 45 by α winding. That is, the center portion 22c of the first cord 22 is disposed so as to pass through the communication groove 46a located at the center portion of the first wound portion 45 in the Z-axis direction, and the one lower wound portion 22d of the first cord 22 extending from the center portion to the end portion passes through the wound region 47 at the next stage from the center. In addition, the other upper wound portion 22e of the first cord 22, which extends from the central portion to the end portion, is passed through one wound region 47 located above the wound region 47 through which the lower wound portion 22d is passed.

Thereafter, the lower wound portion 22d is wound in the same winding region 47 in the left-hand direction more than once when viewed from above the Z axis, and the upper wound portion 22e is wound in the same winding region 47 of the previous stage in the right-hand direction more than once when viewed from above the Z axis. Thereafter, the lower wound portion 22d is moved from the wound winding area 47 to the winding area 47 at the next stage in the Z-axis direction through the communication groove 46a, and is similarly wound in the same direction in this winding area 47. Further, the upper wound portion 22e is moved from the wound winding area 47 to the winding area 47 at the previous stage in the Z-axis direction through the communication groove 46a, and is wound in the same direction in this winding area 47.

By repeating this operation, the first wire is wound around the first winding portion 45 by α. As shown in fig. 2B, the lead portion 22a of the first wire 22 wound with α rises upward in the Z-axis direction from the lower winding portion, and is led out into the vertical lead groove 49a of the lead-out portion 49. The lead portion 22a of the first wire 22 wound with α from the upper winding portion is directly led out into the vertical lead groove 49a of the lead portion 49, passes through the horizontal lead groove 49b, and is led out in a direction different from the other lead portions 22 a.

On the other hand, as shown in fig. 2A and 2B, in the bobbin case 50, the second wire 32 constituting the outer coil 30 as the secondary coil is wound in a row in the second winding portion 55. The aligned winding is a winding method in which the wire 32 is wound around the outer peripheral surface of the winding portion 55 in order from one end to the other end in the Z-axis direction, and in the present embodiment, the aligned winding is performed only in one layer. In the case of the aligned winding in two layers, after the first layer is completely wound, the second layer is wound thereon.

The coil device 10 of the present embodiment is manufactured by assembling the respective members shown in fig. 2A and winding a wire around the bobbin 40 and the bobbin case 50. The coil device 10 may be housed in a case. Further, the inside of the case may be filled with a heat dissipating resin. The heat dissipating resin is not particularly limited, and is preferably a resin having a thermal conductivity of 0.5 to 5, preferably 1 to 3W/m.K, and excellent heat dissipating properties.

Examples of the resin having excellent heat dissipation properties include silicone resins, urethane resins, and epoxy resins, and among them, silicone resins and urethane resins are preferable. In addition, in order to improve heat dissipation, a filler having high thermal conductivity may be filled in the resin.

The heat dissipating resin of the present embodiment preferably has a shore a hardness of 100 or less, and preferably 60 or less. This is because even if the magnetic core 12 is deformed by heat, the deformation is absorbed and excessive stress is not generated in the magnetic core 12. As such a resin, a potting resin can be exemplified.

A cooling device such as a cooling tube or a cooling fin may be attached to the lower side of the case via a metal plate or the like.

Next, an example of a method for manufacturing the coil device 10 will be described with reference to fig. 2A and 2B. In manufacturing the coil device 10, first, the bobbin 40 is prepared. The material of the bobbin 40 is not particularly limited, and the bobbin 40 is formed of an insulating material such as resin.

Next, the first wire 22 is wound around the outer periphery of the first hollow tube portion 44 of the bobbin 40, and the inner coil 20 is formed. The first wire 22 used for forming the inner coil 20 is not particularly limited, but litz wire or the like is preferably used.

Next, the bobbin case 50 is attached to the bobbin 40 on which the inner coil 20 is formed. The second wire 32 constituting the outer coil 30 is wound around the outer periphery of the second hollow cylindrical portion 54 of the bobbin case 50.

Thereafter, the core cover 60 is attached to both sides of the bobbin cover 50 in the Y-axis direction, and thereafter, the core 12 is attached from the up-down direction in the Z-axis direction. That is, the front ends of the center legs 14, 14 and the front ends of the side legs 16, 16 of the core 12 are butted against each other. Further, the front ends of the center legs 14, 14 may have a gap therebetween.

The material of each magnetic core 12 is not particularly limited, and examples thereof include soft magnetic materials such as metal and ferrite. The magnetic core 12 is fixed to the bobbin case 50 and the bobbin 40 by being bonded using an adhesive or being wound around the outer circumference with a band-shaped member.

In the present embodiment, the coil device 10 may be subjected to varnish impregnation treatment after a series of assembly steps. Through the steps described above, the coil device 10 of the present embodiment can be manufactured.

Thereafter, the coil device 10 may be housed inside a case filled with a heat dissipating resin. The resin may be filled before or after the coil device 10 is housed in the case.

Further, since the coil device 10 of the present embodiment can be used as a vertical coil device in which the winding shaft of the coil is disposed perpendicular to the surface of the mounting substrate, the core 12 inserted into the hollow portion of the bobbin 40 is easily cooled.

Further, in the present embodiment, as shown in fig. 2B, since the bobbin case 50 can be divided by the dividing connecting portion 53 parallel to the winding axis, the bobbin case 50 can be easily arranged on the outer periphery of the bobbin 40.

In the coil device 10 of the present embodiment, since the wire 22 is wound in each winding region 47 so that only a single wire winding portion exists along the winding axis direction, it is easy to prevent variation in the number of turns of the wire 22 for each layer, and this contributes to stabilization of the leakage magnetic characteristics. That is, it is easy to strictly control the coupling coefficient between the outer coil 30 constituting the secondary coil and the inner coil 20 constituting the primary coil, and the coil device 10 of the present embodiment can be preferably used as a leakage transformer.

In the present embodiment, since the non-winding portion 57 is provided below the second winding portion 55 of the bobbin case 50 as shown in fig. 2B, the first coil 20 is easily arranged in a position shifted in the Z-axis direction with respect to the second coil 30 as shown in fig. 6B. From this point of view, the leakage magnetic characteristics of the coil device 10 can be easily and accurately adjusted.

Further, in the present embodiment, as shown in fig. 6A and 6B, since the passage recess 56 for drawing the lead portion 22a of the first wire 22 to the upper portion in the reel direction is formed in the inner peripheral portion of the bobbin case 50, the coil device 10 can be downsized.

In the present embodiment, in the portion other than the positions of the passage recess 56 and the communication groove 46a, a relatively small flow gap 46e is uniformly formed between the outer peripheral edge of the winding partition rib 46 and the inner peripheral surface of the bobbin case 50. With this configuration, the distance between the coils 20 and 30 of the wire wound around the inner and outer sides of the bobbin case 50 is easily kept constant, and the variation in the coil characteristic values is reduced.

In particular, in the coil device 10 of the present embodiment, as shown in fig. 2B and 2C, the bobbin case 50 has the non-winding portion 57, and the non-winding portion 57 has the opening portion 57B or the notch portion 57C. Therefore, through the opening 57b or the notch 57c, the heat dissipating resin such as potting resin enters the interior of the bobbin case 50 and enters between the bobbin case 50 and the bobbin 40. As a result, the first wire 22 wound around the first winding portion 45 of the bobbin 40 is in contact with the heat dissipating resin, and heat generated from the first wire 22 is transmitted to the heat dissipating resin to be dissipated satisfactorily. Therefore, in the coil device 10 of the present embodiment, heat dissipation is excellent even if the coil device 10 is downsized.

In the present embodiment, since the bobbin case 50 has the non-winding portion 57, the axial positions of the inner coil 20 made of the first wire 22 and the outer coil 30 made of the second wire 32 are easily shifted. Therefore, the magnetic flux leakage characteristic of the coil device 10 is easily adjusted. Further, as shown in fig. 4 or 5, since a part of the inner coil 20 formed of the first wire 22 can be exposed to the outside of the bobbin case 50 and the coil device 10 through the opening 57b or the notch 57c formed in the non-winding portion 57, the heat radiation performance is improved in this point.

In the present embodiment, the bobbin 40 includes the bobbin base plate 42 and the bobbin upper flange portion 48, and the first winding portion 45 is formed between the two bobbin base plates 42 and the bobbin upper flange portion 48. The bottom surface 57a of the non-winding portion 57 of the bobbin case 50 is disposed on the bobbin base plate 42. With this configuration, the bobbin case 50 can be easily attached to the bobbin 40.

The bobbin case 50 has a case lower flange portion 52 and a case upper flange portion 58. Further, a non-winding portion 57 is provided below the cover lower flange portion 52. Further, the cover flange portion 58 is disposed axially below the bobbin upper flange portion 48, and an outlet gap through which air inside the bobbin cover 50 can be discharged to the outside is formed between the bobbin upper flange portion 48 and the cover flange portion 58.

With this configuration, when the heat dissipating resin enters the interior of the bobbin case 50 from the opening 57b or the notch 57c of the non-winding portion 57, the air located in the interior of the bobbin case 50 is easily discharged from the outlet gap, and the flow of the heat dissipating resin is smoother.

Further, in the present embodiment, the first winding portion 45 is provided with a winding partition rib 46 at a predetermined interval in the axial direction. In some of the winding partition ribs 46, a positioning protrusion 46d for positioning in contact with the inner peripheral surface of the bobbin case 50 is formed in a part in the circumferential direction. As shown in fig. 6A, in the portion other than the positioning convex portion 46d, a flow gap 46e through which the heat dissipating resin can flow is formed uniformly along the circumferential direction between the outer circumferential surface of the winding partition rib 46 and the inner circumferential surface of the bobbin case 50. The heat dissipating resin can be filled in the bobbin case 50 over the entire circumference of the bobbin 40 by flowing in the Z-axis direction through the flow gap 46 e.

The bobbin case 50 is formed of a pair of half-divided bodies 50a and 50b having a divided connecting portion 53. A positioning protrusion 46d is formed in a part of the outer periphery of the winding partition rib 46 of the bobbin 40 so as to contact the inside of the divided connecting portion 53. With this configuration, the strength of the divided connecting portion 53 can be increased, and the uniform flow gaps 46e can be easily formed in the circumferential direction.

In the present embodiment, the first wire 22 disposed on the inner peripheral side is a primary coil of a transformer, and conversely, may be a secondary coil (inner coil 20) that functions at a higher voltage. In that case, the secondary coil (inner coil 20) that operates at a high voltage is disposed inside the primary coil (outer coil 30) that operates at a low voltage, so that insulation is facilitated.

The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the present invention.

For example, the first wire 22 need not be wound α, but may be wound in a row. The operation and effect of the present invention can be expected even in the case of the aligned winding. Further, the specific shape of the bobbins 40 and 40a and the specific shape of the core 12 are not limited to the above-described embodiments, and various modifications may be made. The coil device of the present invention can be used for applications other than a transformer such as a reactor.

Description of the symbols

10 … coil device

12 … magnetic core

13 … base

14 … middle leg

16 … side leg

20 … inner coil

22 … first line

22a … lead part

30 … outside coil

32 … second line

32a … lead part

40 … winding rack

42 … bobbin base plate

42a … leg

44 … first hollow cylinder part

44a … first through hole

44b … separation projection

45 … first winding part

46 … wrapping bulkhead fin (wrapping bulkhead )

46a … communication slot

46b, 46c … notched edge

46d … locating boss

46e … flow-through gap

47 … winding area

48 … flange part on reel

48d … locating boss

49 … lead wire leading part

49a … vertical lead-out groove

49b … horizontal drawing groove

49c … base

49d … insulating wall

49e … engagement projection

50 … bobbin bracket cover

50a, 50b … semi-divided body

52 … cover lower flange part

53 … Split Joint

53a … inboard connector

53b … outside connecting part

53c, 53d … hook

54 … second hollow cylinder part

55 … second winding part

56 … recess for passage

57 … non-winding part

57a … bottom surface

57b … opening part

57c … notch part

57d … column

57e … underbeam

58 … cover upper flange part

58a … is connected to the upper flange portion

58b … to lower flange portion

58c, 58d … engagement tab

58e, 58f … engagement surface

58g, 58h … step surface

58i … stop tab

59 … locating boss

59a … positioning groove

60 … magnetic core cover

62 … cover body

64 … mounting flange

66 … insulating plate portion.

Claims (10)

1. A coil device having:

a bobbin having a first winding portion for winding a first wire around an outer periphery; and

a bobbin case covering a periphery of a bobbin around which the first wire is wound,

wherein the bobbin case has: a second wound portion for winding a second wire different from the first wire around an outer periphery thereof, and a non-wound portion provided at a lower position of the second wound portion in an axial direction thereof,

the non-winding portion has an opening or a notch portion that communicates the inside and the outside of the bobbin case.

2. The coil apparatus according to claim 1,

the size of the opening or the notch is such that the heat dissipating resin located outside the bobbin case can smoothly enter the inside of the bobbin case.

3. The coil device according to claim 1 or 2,

the bobbin has a bobbin base plate and a bobbin upper flange part, the first winding part is formed between the bobbin base plate and the bobbin upper flange part,

the bottom surface of the non-winding portion is disposed on the bobbin base plate.

4. The coil apparatus according to claim 3,

the bobbin case has a case lower flange portion and a case upper flange portion,

the non-winding portion is located below the hood lower flange portion,

the cover upper flange portion is disposed axially below the upper flange portion of the bobbin,

an outlet gap capable of discharging air inside the bobbin case to the outside is formed between the bobbin upper flange portion and the case upper flange portion.

5. The coil apparatus according to claim 2,

the first winding part has a rib for winding a partition wall at a predetermined interval in an axial direction,

a positioning convex part for contacting with the inner peripheral surface of the bobbin case for positioning is formed on a part of any winding partition wall rib in the circumferential direction,

in a portion other than the positioning projection, a flow gap through which the heat dissipating resin flows is formed between an outer peripheral surface of the winding partition rib and an inner peripheral surface of the bobbin case.

6. The coil apparatus according to claim 3,

the first winding part has a rib for winding a partition wall at a predetermined interval in an axial direction,

a positioning convex part for contacting with the inner peripheral surface of the bobbin case for positioning is formed on a part of any winding partition wall rib in the circumferential direction,

in a portion other than the positioning projection, a flow gap through which the heat dissipating resin flows is formed between an outer peripheral surface of the winding partition rib and an inner peripheral surface of the bobbin case.

7. The coil apparatus according to claim 4,

the first winding part has a rib for winding a partition wall at a predetermined interval in an axial direction,

a positioning convex part for contacting with the inner peripheral surface of the bobbin case for positioning is formed on a part of any winding partition wall rib in the circumferential direction,

in a portion other than the positioning projection, a flow gap through which the heat dissipating resin flows is formed between an outer peripheral surface of the winding partition rib and an inner peripheral surface of the bobbin case.

8. The coil apparatus according to claim 5,

the bobbin case is composed of a pair of half-divided bodies having divided connecting portions,

the positioning protrusion is formed to contact the inner side of the divided connecting portion.

9. The coil apparatus according to claim 6,

the bobbin case is composed of a pair of half-divided bodies having divided connecting portions,

the positioning protrusion is formed to contact the inner side of the divided connecting portion.

10. The coil apparatus according to claim 7,

the bobbin case is composed of a pair of half-divided bodies having divided connecting portions,

the positioning protrusion is formed to contact the inner side of the divided connecting portion.

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