The present invention relates to a coil component and, more particularly to a coil component in which a wire is wound around a winding core part thereof in multiple layers.
To increase the inductance of a coil component in which a wire is wound around a winding core part thereof, it is necessary to increase the number of turns of the wire. However, when the wire is wound around a winding core part in a single layer, the length necessary for the winding core part is increased in proportion to the number of turns. Thus, in order to increase the number of turns of the wire while suppressing an increase in the length of the winding core part, the wire needs to be wound around the winding core part in multiple layers as described in JP 2005-44858A and JP 2018-107248A.
Meanwhile, the coil component mainly used in a power supply circuit is required to provide low DC resistance and high rated current. In order to satisfy the requirements, a wire large in diameter should preferably be used.
However, a wire having a large wire diameter is hard to bend, so that the wire needs to be wound with a comparatively strong force at the time of winding work. Thus, when the wire is wound around the winding core part in multiple layers, the lower layer wire may be moved due to a force applied during winding of the upper layer wire to cause the wire to be wound in the upper layer to drop to the lower layer. For example, when the winding structure described in JP 2005-44858A (FIG. 3) is attempted to be obtained, the third turn may drop between the first turn and the second turn and, when the winding structure described in JP 2005-44858A (
It is therefore an object of the present invention to provide a coil component having a winding structure in which a wire to be wound in the upper layer is hard to drop to the lower layer even when the wire has a large wire diameter.
A coil component according to the present invention includes a winding core part and a wire configured such that wire turns thereof from i-th turn (i is an integer equal to or larger than 1) to j-th turn (j is an integer equal to or larger than (i+2)) are wound in this order around the winding core part in an aligned state, that (j-th+1) turn is wound around a valley line formed by i-th turn and (i-th+1) turn, and that (j-th+2) turn is wound adjacent to the j-th turn around the winding core part.
According to the present invention, (j-th+1) turn wound in an upper layer is supported by at least three wire turns positioned in a lower layer, so that even when a wire having a large wire diameter is used, dropout of the wire becomes less apt to occur.
In the present invention, the wire turns from (j-th+2) turn to (j-th+2k) turn (k is a variable starting from 2 and incremented by one) may be wound in this order around the winding core part in an aligned state. Thus, a winding structure in which even-number turns or odd-number turns are wound in the lower layer can be obtained.
In the present invention, (j-th+3) turn may be wound along a valley line formed by (j-th−1) turn and j-th turn. Thus, (j-th+3) turn wound in the upper layer can be supported by at least three wire turns positioned in the lower layer. In addition, a difference in turn number between adjacent turns is small, so that a parasitic capacitance component can be reduced.
In this case, (j-th+2k+1) turn may be wound along a valley line formed by (j-th+2k−4) turn and (j-th+2k−2) turn. Thus, (j-th+2k+1) turn wound in the upper layer can be supported by three wire turns positioned in the lower layer.
In the present invention, (j-th+3) turn may be wound along a valley line formed by (j-th−2) turn and (j-th−1) turn. Thus, (j-th+3) turn poisoned in the upper layer can be supported by at least four wire turns positioned in the lower layer, thus making it possible to prevent dropout of the wire more effectively.
In this case, (j-th+2k+3) turn may be wound along a valley line formed by the (j-th+2k−4) turn and (j-th+2k−2) turn. Thus, (j-th+2k+3) turn wound in the upper layer can be supported by at least four wire turns positioned in the lower layer.
Further, in this case, any of (j-th+2k+3) turns may not be wound along a valley line formed by (j-th+2p) turn (p is an integer equal to or larger than 2) and (j-th+2p+2) turn. Thus, a difference in turn number between adjacent turns is small, so that a parasitic capacitance component can be reduced.
The coil component according to the present invention may further include a flange part and a terminal electrode provided on the flange part and connected with one end of the wire. The i-th turn may be the 1st turn with the terminal electrode as a winding start point. Thus, when the j-th turn is the 3rd or 4th turn, the 4th turn or 5th turn wound in an upper layer can be prevented from dropping.
As described above, the coil component according to the present invention has a winding structure in which a wire to be wound in the upper layer is hard to drop to the lower layer, allowing a wire having a large wire diameter to be used, whereby a low DC resistance and a high rated current can be achieved.
The above features and advantages of the present invention will be more apparent from the following description of certain preferred embodiments taken in conjunction with the accompanying drawings, in which:
Preferred embodiments of the present invention will be explained below in detail with reference to the accompanying drawings.
As illustrated in
The core 10 is a drum-shaped block made of a high-permeability material such as ferrite and has a structure integrating the flange parts 11, 12 and the winding core part 13 provided therebetween. The core 20 is a plate-shaped block also made of a high-permeability material such as ferrite. The cores 10 and 20 are fixed to each other by an adhesive. One end of the wire W is connected to the terminal electrode E1, and the other end thereof is connected to the terminal electrode E2. The dummy terminal electrodes DE1 and DE2 are not connected with the wire W. The terminal electrodes E1, E2 and dummy terminal electrodes DE1, DE2 are each formed of, e.g., silver paste fired on the core 10. The dummy terminal electrodes DE1 and DE2 are connected to a land pattern (or a dummy land pattern) on a printed circuit board through a solder when the coil component 1 is mounted on the printed circuit board so as to increase the mounting strength of the coil component 1. However, in the present invention, such dummy terminal electrodes DE1 and DE2 are not essential.
In place of the terminal electrodes E1 and E2, a terminal fitting may be used. For example, as in a coil component 2 according to a modification illustrated in
In the manufacturing of the coil component 2, first, the terminal fittings 30 and 40 are bonded to the core 10, and then one end of the wire W is connected to the terminal fitting 30. As illustrated in
In the coil component 2 in actual use, the land pattern on the printed circuit board and the mounting parts 31 and 41 of the terminal fittings 30 and 40 are connected through a solder. At this time, the solder reaches the fillet formation parts 35 and 45 by surface tension to forma solder fillet.
In the present embodiment, one wire W is wound around the winding core part 13 of the core 10 in a plurality of turns. Although not particularly limited, the coil component 1 or coil component 2 according to the present embodiment is a coil component for a power supply circuit and is thus required to have a low DC resistance and a high rated current, so that a wire W having a large wire diameter is used therein.
The following describes in detail the winding structure of the wire W.
The number assigned to the wire W in
In the first winding structure illustrated in
More generally, assuming that 1st and 3rd turns are i-th and j-th turns, respectively, i-th turn, (i-th+1) turn (=(j-th−1) turn) and j-th turn are wound in this order around the winding core part 13 in an aligned state, (j-th+1) turn is wound along a valley line formed by i-th turn and (i-th+1) turn, and (j-th+2) turn is wound, adjacent to j-th turn, around the winding core part 13. Then, the turns from (j-th+2) turn to (j-th+2k) turn (k is a variable starting from 2 and incremented by one) are wound in this order around the winding core part 13 in an aligned state, (j-th+3) turn is wound along a valley line formed by (j-th−1) turn and j-th turn, and (j-th+2k+1) turn is wound along a valley line formed by (j-th+2k−4) turn and (j-th+2k−2) turn.
However, the 1st turn is disposed in proximity to the flange part 11, so that the flange part 11 functions as a stopper. Thus, the force F12 poses essentially no problem. On the other hand, a member functioning as a stopper does not exist to the right of the 3rd turn, so that when the magnitude of the force F13 is large, the 4th turn may drop to the lower winding layer L1. However, in the first winding structure, two turns of the 2nd and 3rd turns have already existed to the right of the 4th turn, so that the static friction force of the two turns can prevent the movement of the 2nd and 3rd turns.
On the other hand, as illustrated in
The same applies to when other turns positioned in the upper winding layer L2 are each turned. That is, two turns always exist to the right of a target turn to be wound, making it possible to prevent dropout to the lower winding layer L1. In addition, in the first winding structure, a difference in turn number between the turns vertically contacting each other is suppressed to 5 at maximum, so that an increase of parasitic capacitance component due to proximity between two turns between which a difference in turn number is large can be prevented. That is, a parasitic capacitance component generated by two turns between which a difference in turn number is small is mainly connected in series and is thus reduced in value, while a parasitic capacitance component generated by two turns between which a difference in turn number is large is mainly connected in parallel and thus tends to be increased in value. In the first winding structure, a difference in turn number between the turns vertically contacting each other is suppressed to 5 at maximum, so that an increase in the parasitic capacitance component is suppressed, thus allowing an increase in resonance frequency.
In the second winding structure illustrated in
More generally, assuming that the 1st and 4th turns are i-th and j-th turns, respectively, i-th turn, (i-th+1) turn (=(j-th−2) turn), (i-th+2) turn (=(j-th−1) turn), and j-th turn are wound in this order around the winding core part 13 in an aligned state, (j-th+1) turn is wound along a valley line formed by i-th turn and (i-th+1) turn, (j-th+3) turn is wound along a valley line formed by (j-th−2) turn and (j-th−1) turn, and (j-th+5) turn is wound along a valley line formed by (j-th−1) turn and j-th turn. Then, the turns from (j-th+2) turn to (j-th+2k) turn (k is a variable starting from 2 and incremented by one) are wound in this order around the winding core part 13 in an aligned state, (j-th+2k+3) turn is wound along a valley line formed by the (j-th+2k−4) turn and (j-th+2k−2) turn.
However, like the above-described force F12, the force F22 poses essentially no problem. On the other hand, a member functioning as a stopper does not exist to the right of the 4th turn, so that when the magnitude of the force F23 is large, the 5th turn may drop to the lower winding layer L1. However, in the second winding structure, three turns of 2nd to 4th turns have already existed to the right of the 5th turn, so that the static friction force of the three turns can prevent the movement of 2nd to 4th turns.
The same applies to the case where other turns positioned in the upper winding layer L2 are each turned. That is, three turns always exist to the right of a target turn to be wound, making it possible to prevent dropout to the lower winding layer L1. In addition, in the second winding structure, dropout to the lower winding layer L1 is less likely to occur than in the first winding structure, allowing a wire W having a larger diameter can be used. This can further reduce a DC resistance and further increase a rated current.
The third winding structure illustrated in
The fourth winding structure illustrated in
It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scope and spirit of the invention.
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JP2019-012473 | Jan 2019 | JP | national |
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Number | Date | Country | |
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20200243257 A1 | Jul 2020 | US |