JP7611053B2 - Coil device - Google Patents

Description

The present invention relates to a coil device that is suitable for use in, for example, a common mode filter (common mode choke coil).

As an example of a common mode filter, a coil device in which two wires are wound around a circular core, as shown in Patent Document 1, is known. EMC components such as this common mode filter are installed in electronic devices to reduce noise.

In EMC components, variation in noise reduction characteristics is undesirable. However, in conventional coil devices such as those shown in Patent Document 1, it was found that differences in the mounting direction caused differences in the operating characteristics of the coil. In addition, there is a demand for improved impedance in coil devices.

JP 2014-192169 A

The present invention was made in consideration of the above-mentioned circumstances, and its purpose is to provide a coil device that can improve the difference in the operating characteristics of the coil depending on the mounting direction and has high impedance.

In order to achieve the above object, the coil device of the present invention comprises:
A pair of winding cores arranged approximately parallel to each other along the first axis and spaced apart from each other at a predetermined interval along the second axis;
a wire wound along the first axis on each of the winding cores,
On one winding core, the wire is started to be wound from the inside along the first axis from one side and finished on the inside, and on the other winding core, another wire is started to be wound from the inside along the first axis from one side and finished on the inside.

For example, in the coil device of the present invention,
The positions of the first winding start and end points of each wire located on one side along the first axis are within an inner region of each winding core portion as viewed from the first axial direction,
The positions of the second winding start and end points of each wire located on the other side along the first axis belong to the inner region of each winding core portion when viewed from the first axial direction.

In this invention, the "start and end points" of the wire refer to the positions where the wire wound in a coil around the core first starts to come into contact with the core, or the positions where the wire wound in a coil around the core finishes and leaves contact with the core. After the wire has been wound around the core, it is difficult to tell whether it is the start point of the winding or the end point of the winding.

According to new findings by the inventors, it has been found that by making the start and end points of the wire wound around the pair of winding cores belong to either the outer region or the inner region, it is possible to improve the difference in operating characteristics due to the mounting direction. The reason for this is not necessarily clear, but can be explained as follows, for example.

In conventional coil devices, when winding the wire onto the core from the outside, it was common to end the winding on the inside, and conversely, when winding the wire onto the core from the inside, it was common to end the winding on the outside. This is thought to be to position the connection parts of the lead of the wire at the start of winding and the connection parts of the lead of the wire at the end of winding all on the same side, making connection easier.

However, it was discovered that if the start and end of the wire wound around the core are reversed, from the outside to the inside, the symmetry of the leakage flux cannot be maintained between the start and end of the winding. We hypothesized that this asymmetry of the leakage flux was adversely affecting the characteristics of the coil device, which led to the completion of this invention.

In other words, in the coil device according to the present invention, the start and end points of the wire wound around one winding core are each located in the inner region, and the start and end points of the wire wound around the other winding core are each located in the inner region. This configuration ensures symmetry of leakage magnetic flux between the start and end sides of the winding, and as a result, it is believed that differences in operating characteristics due to mounting direction can be improved.

It was also confirmed that the coil device according to the present invention improves impedance over a wide frequency range. The reason for this is thought to be, for example, as follows. That is, it was confirmed that the difference in operating characteristics due to the mounting direction can be improved even in the coil device according to the reference example, in which the start and end of the windings of a pair of winding cores are both located on the outside. However, this is thought to be because, compared to the coil device according to the reference example, the coil device according to the present invention has an increased coupling coefficient of the coil made of the wire wound around each of the pair of winding cores.

In addition, since the coil device according to the present invention has improved impedance, it is possible to reduce the number of winding turns for the same inductance, which is expected to lead to a smaller coil device.

In the present invention, the inner region of the winding core is the half of the winding core that is closer to the other winding core when viewed from the first axial direction. The outer region of the winding core is the half of the winding core that is opposite the side closer to the other winding core when viewed from the first axial direction.

When viewed from the first axial direction, the first winding start/end point and the second winding start/end point, which are located in the same inner region, may be misaligned from each other along the circumferential direction of the winding core. Arranging the first winding start/end point and the second winding start/end point, which are located in the same inner region, at different positions rather than at the same positions along the circumferential direction, makes the wire winding operation easier and simplifies the arrangement of the connection wire.

Preferably, the coil device of the present invention comprises:
a first connection portion to which lead portions extending from the first winding start and end points of each of the wires are connected;
a second connection portion to which the lead portions extending from the second winding start and end points of the wires are connected,
Along a third axis intersecting both the first axis and the second axis, the first connection portion and the second connection portion are positioned on opposite sides to each other when viewed from the first axial direction.

By positioning the first connection section and the second connection section on opposite sides along the third axis, it becomes easier to position the start and end points of the wire wound around the pair of winding core sections within the inner region.

Preferably, one end of each of the two winding core portions along the first axis is integrally connected to a first flange portion,
The other ends of the two winding core portions along the first axis are integrally connected by a second flange portion, and the first connecting wire portion provided in the first flange portion and the second connecting wire portion provided in the second flange portion are positioned on opposite sides of each other along the third axis when viewed from the first axial direction.

The first connecting wire part may be attached to the first flange by plating, or may be joined to the first flange by adhesive or the like as part of the metal terminal. Similarly, the second connecting wire part may be attached to the second flange by plating, or may be joined to the second flange by adhesive or the like as part of the metal terminal.

Preferably, each of the first connection wire portions is provided on each of the first terminal electrodes, and each of the first terminal electrodes is provided with a first dummy connection wire portion on an opposite side to the first connection wire portion along the third axis,
Each of the second connection wire portions is provided on a corresponding second terminal electrode, and each of the second terminal electrodes is provided with a second dummy connection wire portion on the opposite side along the third axis from the second connection wire portion. More preferably, the first dummy connection wire portion and the second connection wire portion have mounting-side protruding pieces whose tips are located on approximately the same plane.

This configuration makes it easier to mount the coil device on a wiring board, etc., without tilting the coil device.

Preferably, the second dummy connection section and the first connection section have anti-mounting side protruding pieces whose tips are located on approximately the same plane. This configuration makes it easy to attach a cover member having a flat surface on the opposite side of the mounting surface and approximately parallel to the mounting surface onto the anti-mounting side protruding piece. As a result, it becomes easy to pick up and transport the coil device.

Preferably, the non-mounting side protruding piece has a pair of bent pieces that surround, from both sides along the second axis, each of the lead portions that are pulled out from the first winding start and end points of the wire and extend along the first axis. Also preferably, the mounting side protruding piece has a pair of bent pieces that surround, from both sides along the second axis, each of the lead portions that are pulled out from the second winding start and end points of the wire and extend along the first axis.

This configuration makes it easier to connect each lead and minimizes the bending of the wire near the lead, reducing the stress acting on the lead and improving the connection strength of the lead.

FIG. 1 is a perspective view of a coil device according to an embodiment of the present invention. FIG. 2 is an exploded perspective view of the coil device shown in FIG. FIG. 3 is a cross-sectional view of the coil device taken along line III-III shown in FIG. FIG. 4 is a front view of the coil device shown in FIG. FIG. 5 is a perspective view of a terminal electrode of the coil device shown in FIG. FIG. 6A is a schematic diagram showing a measured magnetic flux distribution during operation of a coil device according to an embodiment of the present invention. FIG. 6B is a schematic diagram showing the magnetic flux distribution measured when the coil device shown in FIG. 6A is operated after being mounted by rotating it 180 degrees in the opposite direction around a virtual axis of rotation perpendicular to the mounting substrate. FIG. 6C is a schematic diagram showing the magnetic flux distribution measured when the coil device shown in FIG. 6A is operated after being mounted by rotating it 180 degrees in the opposite direction around a virtual axis of rotation parallel to the mounting substrate. FIG. 7A is a schematic diagram showing the magnetic flux distribution measured during operation of a coil device according to a reference example of the present invention. FIG. 7B is a schematic diagram showing the magnetic flux distribution measured when the coil device shown in FIG. 7A is operated after being mounted by rotating it 180 degrees in the opposite direction around a virtual axis of rotation perpendicular to the mounting substrate. Figure 7C is a schematic diagram showing the magnetic flux distribution measured when the coil device shown in Figure 7A is operated after being mounted by rotating it 180 degrees in the opposite direction around a virtual axis of rotation parallel to the mounting substrate. FIG. 8A is a schematic diagram showing a measured magnetic flux distribution during operation of a coil device according to a comparative example of the present invention. FIG. 8B is a schematic diagram showing the magnetic flux distribution measured when the coil device shown in FIG. 8A is rotated 180 degrees in the opposite direction around a virtual axis of rotation and mounted, and is operated. FIG. 9 shows the measurement results of the impedance of a coil device according to an embodiment of the present invention and the impedance of a coil device of a comparative example.

The present invention will be described below based on the embodiment shown in the drawings. In the drawings, the X-axis (first axis), the Y-axis (second axis), and the Z-axis (third axis) are approximately perpendicular to each other.

1 is suitable for use as, for example, a common mode filter (common mode choke coil) and has a core 10, wires 100 and 110, and terminal electrodes 60 and 80. In this embodiment , the coil device 1 further has a cover 50.

As shown in FIG. 2, the core 10 has two winding cores 12, 14 arranged in parallel (side by side) along the X-axis direction at a predetermined distance in the Y-axis direction. One end of the two winding cores 12, 14 along the X-axis is connected to a first flange 16a of one of them, and the other end of the two winding cores 12, 14 along the X-axis is connected to a second flange 16b of the other of them. In this embodiment, the core 10 is an annular core, and may be molded as a single unit, or molded bodies may be combined and assembled into an annular core.

A wire 100, 110 is wound around each of the winding cores 12, 14 to form each coil. The wires 100, 110 are not particularly limited, and may be, for example, a conductive core wire made of copper or the like, such as a rectangular wire, round wire, twisted wire, Litz wire, or braided wire, or a wire with an insulating coating of such a conductive core wire. The diameter of the wires 100, 110 is not particularly limited, but in this embodiment, the wires have an outer diameter larger than the plate thickness of the terminal electrodes 60, 80, for example, an outer diameter of about 1.2 to 5 times the plate thickness of the terminal electrodes 60, 80.

In this embodiment, the wires 100, 110 are wound with the same number of turns around the respective winding cores 12, 14 in opposite directions when viewed from the X-axis direction. For example, the wire 100 is wound counterclockwise around one winding core 12, and the wire 110 is wound clockwise around the other winding core 14. Two terminal electrodes 60, 80 are attached to each of the flanges 16a, 16b.

The first lead portion 101a, which is one end (left side in FIG. 2) of the wire 100 wound around one winding core portion 12 arranged on the front side along the Y axis in FIG. 2, is connected to the front terminal electrode 60 arranged on one first flange portion 16a. The second lead portion 101b, which is the other end (right side in FIG. 2) of the wire 100, is connected to the front terminal electrode 80 arranged on the other second flange portion 16b. Similarly, the first lead portion 111a, which is one end of the wire 110 wound around the other winding core portion 14 arranged on the rear side along the Y axis in FIG. 2, is connected to the rear terminal electrode 60 arranged on one first flange portion 16a.
The other end of lead 111b is connected to the rear terminal electrode 80 arranged on the other second flange 16b.

The flanges 16a, 16b, which are arranged on opposite sides of the core 10 along the X-axis, have a configuration that is point-symmetrical (or line-symmetrical) with respect to each other. Each flange 16a, 16b has an outer end face 24 located at the end along the X-axis of the core 10, an inner end face 25 located on the opposite side, a mounting-side lower face 22, an upper face 20 located on the opposite side, and first and second side faces 26, 28 located at both ends of the core 10 along the Y-axis.

The outer end faces 24 of each flange portion 16a, 16b have a central outer end face 24a located in the center in the Y-axis direction, and side outer end faces 30, 32 located on both sides of the central outer end face 24a in the Y-axis direction. The side outer end faces 30, 32 are slightly recessed in a stepped shape along the X-axis from the central outer end face 24a, but these outer end faces 24a, 30, 32 are approximately parallel to a plane including the Z-axis and Y-axis. The step height along the X-axis between the central outer end face 24a and the side outer end face 30 (or 32) may be 0, but is preferably equal to or less than the plate thickness of the terminal electrode 60 or 80.

One or the other X-axis end of each of the winding cores 12, 14 is integrally connected to the inner end faces 25, 25 of each of the flanges 16a, 16b. A groove 38 is formed in the center of the Y-axis direction of the inner end faces 25, 25 of each of the flanges 16a, 16b, extending along the Z-axis from the upper surface 20 of the flanges 16a, 16b toward the mounting-side lower surface 22. The groove 38 is located in the middle of the part where the winding cores 12, 14 are connected to the flanges 16a, 16b.

As shown in FIG. 3, a chamfered portion 25α is formed on the inner end surface 25 of each of the flanges 16a and 16b below the Z axis and extending to the mounting side lower surface 22, and a chamfered portion 24α is also formed on the outer end surface 24 below the Z axis and extending to the mounting side lower surface 22. The presence of these chamfered portions 24α and 25α makes it easier to mold (remove) the core 10.

As shown in FIG. 3, in this embodiment, the upper surface 20 of each of the flanges 16a, 16b is lower than the maximum height of the winding core 12 along the Z axis by a predetermined step height (preferably 0.5 to 5 times the plate thickness of the terminal electrode 60 or 80), but the step height need not be present. Also, the upper surface 20 of each of the flanges 16a, 16b may be configured to be higher than the maximum height of the winding core 12 along the Z axis.

As shown in FIG. 2, at both ends of each flange 16a, 16b in the Y-axis direction, the lower ends of the first side surface 26 and the second side surface 28 are cut out to form locking receiving portions 34 and 36, respectively. Locking claws 54, 55 formed at the lower ends of legs 52, 53 provided at the four corners of the cover 50 are adapted to detachably engage with each locking receiving portion 34, 36.

To form notched locking receiving portions 34, 35 below both ends in the Y-axis direction of each flange 16a, 16b, the width in the Y-axis direction of the mounting side lower surface 22 is made narrower than the width in the Y-axis direction of the upper surface 20. However, the width in the Y-axis direction of the mounting side lower surface 22 is greater than the width in the Y-axis direction of the central outer end surface 24a, and is determined so that the width of the side outer end surfaces 30, 32 on the mounting side lower surface 22 side can be secured with sufficient dimensions.

As shown in FIG. 2, the cover 50 has a flat lid portion 51 and legs 52, 53 that branch off from both ends of the lid portion 51 along the Y axis, along the X axis, and then protrude downward along the Z axis. The aforementioned locking claws 54, 55 are integrally formed on the lower ends of the legs 52, 53 along the Z axis.

The cover 50 also has a pair of convex block portions 58 that protrude on both sides along the X-axis from the lower part near the center along the Y-axis of the lid portion 51. Each convex block portion 58 is capable of abutting against the center along the Y-axis of the upper surface 20 of each flange portion 16a, 16b. A plate-shaped partition portion 56 that extends along the X-axis to connect the pair of convex block portions 58 is integrally formed on the lower surface of the lid portion 51 located at the center along the Y-axis.

The lower end of the plate-shaped partition 56 along the Z axis protrudes further downward along the Z axis than the lower end of the convex block 58 along the Z axis, and both side ends of the plate-shaped partition 56 along the X axis are attached to the grooves 38 formed in the inner end surfaces 25 of the flanges 16a and 16b so as to be able to slide up and down. The partition 56 effectively prevents the wires 100 and 110 wound in coils around the cores 12 and 14 from contacting each other, ensuring their insulation. The top surface of the lid 51 of the cover 50 is flat and can be attracted to a suction nozzle or the like, making it easy to transport the coil device 1.

The cover 50 is made of a non-magnetic material such as resin, but the resin may contain a magnetic material such as a metal magnetic material or ferrite. The cover 50 may also be made of a magnetic material such as a metal magnetic material or ferrite, like the core 10. When the cover 50 is made of a magnetic material or contains a magnetic material, the cover 50 may form a closed magnetic circuit together with the core 10.

As shown in FIG. 5, the terminal electrodes 60 and 80 have the same shape and size, but the terminal electrode 60 attached to the first flange 16a and the terminal electrode 80 attached to the second flange 16b shown in FIG. 2 have the reversed arrangement of the connection wire portion and the dummy connection wire portion in the upper and lower Z-axis directions. Each terminal electrode 60, 80 has a terminal main piece (terminal main portion) 62, 82, a connection wire portion 70, 90, and a dummy connection wire portion 78, 98, which are formed by bending a single metal piece with a substantially uniform plate thickness. The dummy connection wire portions 78, 98 are arranged on the opposite side of the terminal main pieces 62, 82 from the connection wire portions 70, 90 along the Z-axis, and have the same shape and size as the connection wire portions 70, 90.

In this embodiment, the connection wire parts 70, 90 and the dummy connection wire parts 78, 98 have base pieces 68, 88 and protruding pieces 76, 96. The connection wire part 70 of the terminal electrode 60 is located at the top in the Z-axis direction and is the part to which the first lead part 101a of the wire 100 or the first lead part 111a of the wire 110 shown in FIG. 4 is connected. The connection wire part 90 of the terminal electrode 80 shown in FIG. 5 is the part to which the second lead part 101b of the wire 100 is connected as shown in FIG. 3, and is also the part to which the second lead part 111b of the wire 110 shown in FIG. 4 is connected. The first lead parts 101a, 111a and the second lead parts 101b, 111b are not connected to the dummy connection wire parts 78, 98.

As shown in FIG. 3, the base pieces 68, 88 located above the terminal electrodes 60, 80 in the Z-axis direction are bent and formed approximately vertically from the upper ends of the main terminal pieces 62, 82 along the Z-axis toward the upper surfaces 20, 20 of the flanges 16a, 16b so that they are installed along the upper surfaces 20, 20 of the flanges 16a, 16b. The base pieces 68, 88 may be bonded to the upper surfaces 20, 20 of the flanges 16a, 16b, but may also be engaged with the upper surfaces 20, 20 without being bonded, or may be arranged to face the upper surfaces 20, 20 of the flanges 16a, 16b with a certain distance between them.

The other base piece 68, 88 located below the terminal electrodes 60, 80 in the Z-axis direction is bent substantially vertically from the lower end of the terminal main piece 62, 82 along the Z-axis toward the mounting side lower surface 22, 22 of the flange portion 16a, 16b so as to be disposed along the mounting side lower surface 22, 22 of the flange portion 16a, 16b.
, 16b, or may be engaged with the mounting side lower surfaces 22, 22 without being adhered, or may be arranged so as to face the mounting side lower surfaces 22, 22 of each flange portion 16a, 16b with a certain distance therebetween.

As shown in FIG. 5, on both sides of each base piece 68 of the terminal electrode 60 along the Y axis, protruding pieces 76 are integrally bent and molded so as to protrude at an angle toward the outside (upper or lower side) of the Z axis. Each protruding piece 76 is inclined at an acute angle with respect to the base piece 68 so that its tip approaches on the base piece 68. As shown in FIG. 4, it is possible to crimp the lead portion 101a or 111a between the pair of protruding pieces 76 on the top of the base piece 68 of the connection part 70 (upper surface in the Z axis direction). The first lead 101a (111a) of the wire 100 (110) is connected to each base piece 68 with solder 5 or the like while being sandwiched between the pair of protruding pieces 76.

As shown in FIG. 5, similar to the terminal electrode 60, on both sides of each base piece 88 of the terminal electrode 80 along the Y axis, protruding pieces 96 are integrally bent and molded so as to protrude at an angle toward the outside (upper or lower side) of the Z axis. Each protruding piece 96 is inclined at an acute angle with respect to the base piece 88 so that its tip approaches on the base piece 88. Also, it is possible to crimp the lead portion 101b or 111b between the pair of protruding pieces 96 on the top of the base piece 88 of the connection wire part 90 (the lower surface in the Z axis direction). The second lead 101b (111b) of the wire 100 (110) is connected to each base piece 88 with solder 5 or the like while being sandwiched between the pair of protruding pieces 96.

As shown in FIG. 3, each terminal main piece 62, 82 is arranged to face the outer end surface 24, 24 of each flange portion 16a, 16b, and is bonded with adhesive to the lateral outer end surfaces 30, 32 located on both sides in the Y-axis direction of the outer end surface 24 of each flange portion 16a, 16b shown in FIG. 2.

The terminal electrodes 60, 80 are made of metals such as tough pitch steel, phosphor bronze, brass, iron, nickel, nickel alloy, and stainless steel. The terminal electrodes 60, 80 can be integrally formed by punching and pressing a conductive metal plate, bending it, and forming it into a single piece. In addition, it is preferable that the connection parts 70, 90 and the dummy connection parts 78, 98 are formed with a plating film of tin or an alloy containing tin as a solder adhesion enhancing layer.

Next, the relationship between the wires 100, 110, the winding cores 12, 14, and the terminal electrodes 60, 80 will be described in detail. The relationship between the wires 110, the winding core 14, and the terminal electrodes 60, 80 is the same as the relationship between the wire 100, the winding core 12, and the terminal electrodes 60, 80, except that the wire 110 is wound around the winding core 14 in the opposite direction, and therefore some of the description will be omitted.

As shown in FIG. 1, the wire 100 is wound counterclockwise in multiple turns along the X-axis around the winding core 12. The tip of the first lead portion 101a, which is one end of the wire 100 in the X-axis direction, is connected to the upper base piece 68 of the terminal electrode 60 arranged on the front side along the Y-axis of the first flange 16a, and extends in the X-axis direction between a pair of protruding pieces 76. In this embodiment, the wire 100 is inclined downward and leftward from the tip of the first lead portion 101a toward the winding core 12, contacts the winding core 12 at the first winding start/end point 102a, and is wound around the winding core 12 in the same direction.

After the wire 100 is wound counterclockwise around the winding core 12 in multiple turns along the X-axis, the second lead portion 101b of the wire 100 leaves the winding core 12 at the second winding start/end point 102b of the wire and is pulled out obliquely toward and connected to the lower base piece 88 of the terminal electrode 80 shown in FIG. 3. On the lower surface of the base piece 88, the tip of the second lead portion 101b of the wire 100 is pulled out along the X-axis.

The first winding start/end point 102a is the part where the coil winding begins if winding of the wire 100 starts around the winding core 12 from the first lead portion 101a, and is the part where the coil winding ends if winding of the wire 100 starts around the winding core 12 from the second lead portion 101b shown in FIG. 3. The second winding start/end point 102b is the part where the coil winding ends if winding of the wire 100 starts around the winding core 12 from the first lead portion 101a, and is the part where the coil winding begins if winding of the wire 100 starts around the winding core 12 from the second lead portion 101b.

In this embodiment, the first winding start/end point 102a, which is the start or end of the wire 100 wound around the winding core 12, is located so as to belong to the inner region 12b from a straight line along the Z axis including the central axis O1 of the coil shown in FIG. 4. The second winding start/end point 102b, which is the start or end of the wire 100 wound around the winding core 12, is also located so as to belong to the inner region 12b. However, the first winding start/end point 102a and the second winding start/end point 102b are at different positions along the Z axis and are located in opposite directions to each other with respect to a line parallel to the Y axis including the central axis O1.

The central axis O1 of the coil is the center line along the X-axis of the winding core 12 shown in FIG. 1. The inner region 12b of the winding core 12 is the half of the winding core 12 that is closer to the other winding core 14 when viewed from the X-axis direction. The outer region 12a of the winding core 12 is the half of the winding core 12 that is opposite the side closer to the other winding core 14 when viewed from the X-axis direction.

Similarly, as shown in FIG. 1, the wire 110 is wound clockwise along the X-axis with multiple turns (the same number of turns as the wire 100) around the winding core 14. The tip of the first lead portion 111a, which is one end of the wire 110 in the X-axis direction, is connected to the upper base piece 68 of the terminal electrode 60 located at the rear side along the Y-axis of the second flange 16b, and extends in the X-axis direction between a pair of protruding pieces 76. In this embodiment, the wire 110 is inclined in the lower right direction from the tip of the first lead portion 111a toward the winding core 12, contacts the winding core 14 at the first winding start/end point 112a, and is wound around the winding core 14 in the same direction.

After the wire 110 is wound clockwise around the winding core 14 in multiple turns along the X-axis, as shown in FIG. 4, the second lead portion 111b of the wire 110 leaves the winding core 12 at the second winding start/end point 112b of the wire and is pulled out obliquely toward and connected to the base piece 88 below the terminal electrode 80. On the underside of the base piece 88, the tip of the second lead portion 111b of the wire 110 is pulled out along the X-axis.

The first winding start/end point 112a is the part where the coil winding begins if winding of the wire 100 starts around the winding core 14 from the first lead portion 111a, and is the part where the coil winding ends if winding of the wire 110 starts around the winding core 14 from the second lead portion 111b. The second winding start/end point 112b is the part where the coil winding ends if winding of the wire 110 starts around the winding core 14 from the first lead portion 111a, and is the part where the coil winding begins if winding of the wire 110 starts around the winding core 14 from the second lead portion 111b.

In this embodiment, the first winding start/end point 112a, which is the start or end of the wire 110 wound around the winding core 14, is located so as to belong to the inner region 14b from a straight line along the Z axis including the central axis O2 of the coil shown in FIG. 4. The second winding start/end point 112b, which is the start or end of the wire 110 wound around the winding core 14, is also located so as to belong to the inner region 14b. However, the first winding start/end point 102b and the second winding start/end point 112b are at different positions along the Z axis and are located in opposite directions to each other with respect to a line parallel to the Y axis including the central axis O2.

The central axis O2 of the coil is a center line along the X-axis of the winding core 14 shown in Fig. 1. The inner region 14b of the winding core 14 is a half region on the side closer to the other winding core 12 when viewed from the X-axis direction of the winding core 14. The outer region 14a of the winding core 14 is a half region on the opposite side to the side closer to the other winding core 12 when viewed from the X-axis direction of the winding core 14.

In the coil device 1 according to this embodiment, for example, in one of the pair of winding cores 12, 14, in one winding core 12, the wire 100 is started to be wound from the inside along one side along the X-axis and ends on the inside, and in the other winding core 14, another wire 110 is similarly started to be wound from the inside along the X-axis along one side and ends on the inside.

That is, the first winding start/end point 102a and the second winding start/end point 102b of the wire 100 wound around the winding core 12 belong to the inner region 12b, and the first winding start/end point 112a and the second winding start/end point 112b of the wire 110 wound around the winding core 14 belong to the inner region 14b. This configuration ensures symmetry of leakage magnetic flux between the winding start side and the winding end side, and as a result, the difference in operating characteristics due to the mounting direction can be improved.

In addition, in this embodiment, the first winding start/end point 102a (112a) and the second winding start/end point 102b (112b), which are located in the inner region 12b (14b) on the same side as viewed from the X-axis direction, are misaligned from each other along the circumferential direction of the winding core portion 12 (14). Arranging the first winding start/end point 102a (112a) and the second winding start/end point 102b (112b), which are located in the inner region 12b (14b) on the same side, at different positions rather than at the same positions along the circumferential direction makes it easier to wind the wire 100 (110) and simplifies the arrangement of the connection portion 70 (90).

Furthermore, in this embodiment, as shown in FIG. 4, the first connection parts 70, 70 to which the lead parts 101a, 111a extending from the first winding start/end points 102a, 112a, respectively, are connected, and the second connection parts 90, 90 to which the lead parts 101b, 111b extending from the second winding start/end points 102b, 112b, respectively, are connected, are located on opposite sides of each other along the Z axis.

By positioning the first connection section 70, 70 and the second connection section 90, 90 on opposite sides along the Z axis, it becomes easier to position the winding start and end points 102a, 102b, 112a, 112b of the wires 100, 110 wound around the pair of winding cores 12, 14, respectively, within the respective inner regions 12b, 14b.

Furthermore, in this embodiment, each of the first connection parts 70, 70 is provided on each of the first terminal electrodes 60, 60, and each of the first terminal electrodes 60, 60 is provided with a first dummy connection part 78, 78 on the opposite side of the first connection part 70, 70 along the Z axis. Also, each of the second connection parts 90, 90 is provided on each of the second terminal electrodes 80, 80, and each of the second terminal electrodes 80, 80 is provided with a second dummy connection part 98 on the opposite side of the second connection part 90, 90 along the Z axis. The first dummy connection parts 78, 78 and the second connection parts 90, 90 have protruding pieces 76, 96 on the mounting side where the tips are located on approximately the same plane. By configuring in this way, it becomes easy to mount the coil device 1 on a wiring board or the like without tilting the coil device 1.

The second dummy connection wire parts 98, 98 and the first connection wire parts 70, 70 have protruding pieces 76, 96 on the non-mounting side whose tips are located on approximately the same plane. This configuration makes it easy to attach the cover member 50, which has a flat surface on the opposite side to the mounting surface and approximately parallel to the mounting surface, onto the protruding pieces 76, 96 on the non-mounting side. As a result, the coil device 1 can be easily picked up and transported. In addition, in this embodiment, if the cover 50 is not provided, the coil device 1 can be used without any problem even if either the upper or lower surface in the Z-axis direction is mounted on a circuit board, etc.

Furthermore, in this embodiment, the protruding pieces 76, 96 have a pair of bent pieces that surround the tip of each lead portion 101a, 111a, 101b, 111b that extends along the X axis of each of the wires 100, 110 from both sides along the Y axis. This configuration makes it easier to connect the leads 101a, 111a, 101b, 111b, and minimizes the bending of the wires 100, 110 near the leads 101a, 111a, 101b, 111b, reducing the stress acting on the leads 101a, 111a, 101b, 111b and improving the connection strength of the leads 101a, 111a, 101b, 111b to the terminal electrodes 60, 80.

In this embodiment, each of the wires 100 and 110 is wound around each of the winding cores 12 and 14 in a line-symmetrical manner, allowing them to function favorably as a common mode filter.

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

For example, in the above-described embodiment, the terminal electrodes 60, 80 are formed of conductive plate pieces, and the connecting wire portions 70, 90 and the terminal main portions 62, 82 connected to the connecting wire portions 70, 90 are integrally formed on the conductive plate pieces, but this is not limited thereto. For example, the terminal electrodes including at least the connecting wire portions 70, 90 may be formed as a plating film formed on the surfaces of the flange portions 16a, 16b.

In the above-described embodiment, as shown in FIG. 4, the first lead 101a, 111a and the second lead 101b, 111b of the wire 100, 110 are connected to the terminal electrode 60 or 80 by solder 5, but they may be connected by other methods such as laser welding, thermocompression bonding, arc welding, and resistance welding.

Furthermore, the coil device 1 can be used not only as a common mode filter (common mode choke coil) but also as a balun transformer, pulse transformer, choke coil, signal transformer, winding product, etc. In the above-described embodiment, the wires 100, 110 are wound around the respective winding cores 12, 14 with the same number of turns in opposite directions as viewed from the X-axis direction, but may be wound with different numbers of turns.

The present invention will be described below in more detail with reference to examples, but the present invention is not limited to these examples.

Example 1
For the coil device 1 shown in FIG. 1 (without the cover 50 attached), a computer simulation was performed on the leakage magnetic flux when the direction of the current flow was changed.

Figure 6A shows the results of a leakage flux simulation performed on the coil device 1 according to the first embodiment, where a current is passed from the terminal 60 indicated by the symbol a1 to the terminal 80 indicated by the symbol b1, the terminal 80 indicated by the symbol c1, and the terminal 60 indicated by the symbol d1, in that order. Also, Figure 6B shows the results of a leakage flux simulation performed on the assumption that the arrangement of the terminals of the coil device 1 shown in Figure 6A is rotated around the Z axis so that the mounting direction is reversed. That is, Figure 6B shows the results of a leakage flux simulation performed on the coil device 1 according to the first embodiment, where a current is passed from the terminal 80 indicated by the symbol c1 to the terminal 60 indicated by the symbol d1, the terminal 60 indicated by the symbol a1, and the terminal 80 indicated by the symbol b1, in that order.

Figure 6C shows the results of a leakage flux simulation performed assuming that the terminal arrangement of the coil device 1 shown in Figure 6A is rotated around the Y-axis so that the mounting surface is reversed. That is, in Figure 6C, a current is passed from the terminal 80 shown by the symbol b1 to the terminal 60 shown by the symbol a1, the terminal 60 shown by the symbol d1, and the terminal 80 shown by the symbol c1 in this order, and the results are shown for a leakage flux simulation.

In Figures 6A to 6C, B1, B2, B3, and B4 respectively represent the magnetic flux density of the leakage magnetic flux, with B1 having the highest magnetic flux density and gradually decreasing to B2, B3, and B4.

In addition, the impedance of the coil device 1 according to Example 1 was measured by changing the frequency. The results are shown by the solid line in FIG. 9. An impedance analyzer was used to measure the impedance. The coupling coefficient of the coil device was measured and found to be 0.945.

Reference Example 1
For the coil device 2 shown in FIG. 7A, a computer simulation was performed on the leakage magnetic flux when the direction of the current flow was changed.

Figure 7A shows the results of a leakage flux simulation performed on the coil device 2 according to Reference Example 1, where current is passed from the terminal 60 indicated by the symbol a2 to the terminal 80 indicated by the symbol b2, the terminal 80 indicated by the symbol c2, and the terminal 60 indicated by the symbol d2, in that order. Also, Figure 7B shows the results of a leakage flux simulation performed on the assumption that the arrangement of the terminals of the coil device 2 shown in Figure 7A is rotated around the Z axis so that the mounting direction is reversed. That is, Figure 7B shows the results of a leakage flux simulation performed on the coil device 2, where current is passed from the terminal 80 indicated by the symbol c2 to the terminal 60 indicated by the symbol d2, the terminal 60 indicated by the symbol a2, and the terminal 80 indicated by the symbol b2, in that order.

Figure 7C shows the results of a leakage flux simulation performed assuming that the terminal arrangement of the coil device 2 shown in Figure 7A is rotated around the Y-axis so that the mounting surface is reversed. That is, in Figure 7C, a current is passed from the terminal 80 shown at b2 to the terminal 60 shown at a2, the terminal 60 shown at d2, and the terminal 80 shown at c2 in this order, and the results are shown of a leakage flux simulation.

In Figures 7A to 7C, B1a, B2a, B3a, and B4a respectively represent the magnetic flux density of the leakage magnetic flux, with B1a having the highest magnetic flux density and gradually decreasing to B2a, B3a, and B4a.

In the coil device according to Reference Example 1, in one of the pair of winding cores 12, the wire 100 starts to be wound from the outside along the X-axis from one side and ends on the outside, and in the other winding core 14, another wire 110 similarly starts to be wound from the outside along the X-axis from one side and ends on the outside. The other configurations of Reference Example 1 are the same as those of Example 1.

Furthermore, in the same manner as in Example 1, impedance measurements were performed at different frequencies for the coil device 2 according to Reference Example 1. The results are shown by the dotted line in Figure 9. Similarly, the coupling coefficient was measured for the same coil device and found to be 0.924.

Comparative Example 1
A computer simulation was performed on the leakage magnetic flux when the direction of current flow was changed for the conventional coil device 3 in which all the lead parts are connected to the connecting wire parts arranged on the upper surface of the flange part. That is, in the conventional coil device 3, the coil was wound in such a way that the wire wound around each winding core part started from the outside and ended on the inside, or started from the inside and ended on the outside.

Fig. 8A shows the result of simulating leakage flux in the coil device 3 by passing a current from the terminal 60a shown by the symbol a3 to the terminal 80a shown by the symbol b3, the terminal 80a shown by the symbol c3, and the terminal 60a shown by the symbol d3 in this order. Fig. 8B shows the result of simulating leakage flux in the coil device 3 by assuming that the arrangement of the terminals of the coil device 3 shown in Fig. 8A is rotated around the Z-axis so that the arrangement is reversed and the mounting direction is reversed. That is, Fig. 8B shows the result of simulating leakage flux by passing a current from the terminal 80a shown by the symbol C3 to the terminal 60a shown by the symbol d3, the terminal 60a shown by the symbol a3, and the terminal 80a shown by the symbol b3 in this order.

In Figures 8A and 8B, B1b, B2b, B3b, and B4b respectively represent the magnetic flux density of the leakage magnetic flux, with B1b having the highest magnetic flux density and gradually decreasing to B2b, B3b, and B4b.

It was confirmed that, compared to the change in leakage flux shown in Comparative Example 1 shown in Figures 8A and 8B, the change in leakage flux is small in Example 1 shown in Figures 6A and 6B and Reference Example 1 shown in Figures 7A and 7B even when the mounting direction is reversed. That is, it was predicted that the change in operating characteristics due to the difference in mounting direction is small in Example 1 and Reference Example 1 compared to Comparative Example 1. It was also confirmed that the region where leakage flux becomes large can be minimized in Example 1 compared to Reference Example 1.

In Example 1 shown in Figures 6A and 6C, and Reference Example 1 shown in Figures 7A and 7C, it was confirmed that the change in leakage magnetic flux was small even when the mounting surface was reversed. In other words, in Example 1 and Reference Example 1, unlike Comparative Example 1, it was possible to predict that they could be used without problems even if the mounting surface was reversed.

Furthermore, as shown in FIG. 9, it was confirmed that the impedance characteristics were improved in Example 1 compared to Reference Example 1.

1, 2, 3... Coil device 5... Solder 10... Core 12, 14... Winding core portion 12a, 14a... Outer region 12b, 14b... Inner region 16a... First flange portion 16b... Second flange portion 20... Upper surface 22... Mounting side lower surface 24... Outer end surface 24a... Central outer end surface 25... Inner end surface 26... First side surface 28... Second side surface 30, 32... Lateral outer end surfaces 34, 36... Locking receiving portion 38... Groove portion 50... Cover 51... Lid portion 52, 53... Leg portion 54, 55... Locking claw 56... Partition portion 58... Convex block portion 60, 80... Terminal electrode 60a, 80a... Outer surface 60b, 80b... Inner surface 62, 82... Terminal main piece (terminal main portion)
68, 88... base pieces 70, 90... connection parts 76, 96... protruding pieces 78, 98... dummy connection parts 100, 110... wires 101a, 111a... first lead parts 101b, 111b... second lead parts 102a, 112a... first winding start/end points 102b, 112b... second winding start/end points

Claims (7)

A coil device including a pair of winding cores arranged substantially parallel to a first axis and spaced apart from each other by a predetermined distance along a second axis, and a wire wound around each of the winding cores along the first axis,
On one winding core, the wire is wound from one side along the first axis from the inside and ends on the inside, and on the other winding core, another wire is wound from one side along the first axis from the inside and ends on the inside ,
The positions of the first winding start and end points of each wire located on one side along the first axis are within an inner region of each winding core portion as viewed from the first axial direction,
The positions of the second winding start and end points of each wire located on the other side along the first axis are within an inner region of each winding core portion as viewed from the first axial direction,
a first connection portion to which lead portions extending from the first winding start and end points of each of the wires are connected;
a second connection portion to which the lead portions extending from the second winding start and end points of the wires are connected,
the first connection portion and the second connection portion are located on opposite sides to each other as viewed from the first axial direction along a third axis intersecting both the first axis and the second axis,
Each of the first connection wire portions is provided on a corresponding one of the first terminal electrodes, and each of the first terminal electrodes is provided with a first dummy connection wire portion on an opposite side to the first connection wire portion along the third axis,
Each of the second connection wire portions is provided on a corresponding second terminal electrode, and each of the second terminal electrodes is provided with a second dummy connection wire portion on an opposite side to the second connection wire portion along the third axis,
The first dummy connection portion and the second connection portion have mounting-side protruding pieces whose tips are positioned on approximately the same plane. The coil device according to claim 1, wherein the first winding start/end points and the second winding start/end points , which are located within the same inner region when viewed from the first axial direction, are offset from each other along the circumferential direction of the winding core portion. One end of each of the two winding core portions along the first axis is integrally connected to a first flange portion,
3. The coil device according to claim 1 or 2, wherein the other ends of the two winding core portions along the first axis are integrally connected by a second flange portion, and the first connection portion provided on the first flange portion and the second connection portion provided on the second flange portion are positioned on opposite sides of each other along the third axis when viewed from the first axial direction. The coil device according to any one of claims 1 to 3 , wherein the second dummy connection portion and the first connection portion have anti-mounting side protruding pieces whose tips are positioned on approximately the same plane. The coil device as described in claim 4, wherein the anti-mounting side protruding piece has a pair of bent pieces that surround each lead portion, which is pulled out from each of the first winding start and end points of the wire and extends along the first axis, from both sides along the second axis. A coil device as described in any one of claims 1 to 5, wherein the mounting side protruding piece has a pair of bent pieces that surround each lead portion, which is pulled out from each second winding start and end point of the wire and extends along the first axis, from both sides along the second axis. A coil device including a pair of winding cores arranged substantially parallel to a first axis and spaced apart from each other by a predetermined distance along a second axis, and a wire wound around each of the winding cores along the first axis,
On one winding core, the wire is wound from one side along the first axis from the inside and ends on the inside, and on the other winding core, another wire is wound from one side along the first axis from the inside and ends on the inside,
The positions of the first winding start and end points of each wire located on one side along the first axis are within an inner region of each winding core portion as viewed from the first axial direction,
The positions of the second winding start and end points of each wire located on the other side along the first axis are within an inner region of each winding core portion as viewed from the first axial direction,
a first connection portion to which lead portions extending from the first winding start and end points of each of the wires are connected;
a second connection portion to which the lead portions extending from the second winding start and end points of the wires are connected,
Each of the first connection wire portions is provided on a corresponding one of the first terminal electrodes, and each of the first terminal electrodes is provided with a first dummy connection wire portion on an opposite side to the first connection wire portion along a third axis intersecting both the first axis and the second axis,
Each of the second connection wire portions is provided on a corresponding second terminal electrode, and each of the second terminal electrodes is provided with a second dummy connection wire portion on an opposite side to the second connection wire portion along the third axis,
The first dummy connection portion and the second connection portion have mounting-side protruding pieces whose tips are positioned on approximately the same plane.

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