This application claims benefit of priority to Japanese Patent Application No. 2020-188962, filed Nov. 12, 2020, the entire content of which is incorporated herein by reference.
The present disclosure relates to a coil component in which a wire is wound around a winding core of a core.
Japanese Patent Application Laid-Open No. 2018-148078 discloses an example of a coil component in which a wire is wound around a winding core of a core. In this coil component, a terminal electrode is provided on a flange of the core, and an end of the wire is electrically connected to the terminal electrode.
An example of a method of electrically connecting the end of the wire to the terminal electrode will be described. For example, the end of the wire is temporarily fixed to the terminal electrode by thermal pressure bonding. By melting a metal constituting the terminal electrode in this state, a molten ball is created. The end of the wire can be electrically connected to the terminal electrode by the molten ball that become solidified.
When the metal constituting the terminal electrode is melted to create the molten ball, heat of the terminal electrode is also transferred to the wire whose end is temporarily fixed to the terminal electrode. The larger an amount of heat transferred to the wire is, the more greatly the wire is damaged.
Accordingly, a coil component includes a core having a winding core and a flange connected to an end of the winding core in an axial direction of the winding core, a terminal electrode provided on the flange, and a wire having an end and a winding portion wound around the winding core. The end is electrically connected to the terminal electrode. A part of the end is spaced apart from the terminal electrode.
In the above configuration, a part of the end of the wire is spaced apart from the terminal electrode. Therefore, heat is less likely to transfer from the terminal electrode to the wire as compared with a case where the end of the wire as a whole is in contact with the terminal electrode.
The present disclosure makes heat less likely to transfer from the terminal electrode to the wire.
Hereinafter, an embodiment of a coil component will be described with reference to
As illustrated in
The core 20 contains, for example, an electrically insulating material. Specifically, the core 20 contains a non-magnetic material such as alumina or a resin, and a magnetic material such as ferrite or a magnetic powder-containing resin. The core 20 is preferably constituted by a sintered body such as alumina or ferrite.
The core 20 includes a winding core 21, a first flange 22 connected to a first end of the winding core 21 in an axial direction Z1, and a second flange 23 connected to a second end of the winding core 21 in the axial direction Z1. That is, the winding core 21 extending in the axial direction Z1 is disposed between a pair of the flanges 22 and 23 aligned in the axial direction Z1. The axial direction Z1 is an extending direction of a central axis F of the winding core 21.
Among side surfaces of the flanges 22 and 23, a side surface corresponding to a circuit board when the coil component 10 is mounted on the circuit board is referred to as a mounting surface 25a. In the embodiment, among directions orthogonal to the axial direction Z1, a direction along the mounting surface 25a is referred to as a first direction Z2, and a direction orthogonal to the mounting surface 25a is referred to as a second direction Z3.
Each of the flanges 22 and 23 protrudes outward in the first direction Z2 from the winding core 21 and protrudes outward in the second direction Z3 from the winding core 21. The mounting surface 25a is a side surface on a first side in the second direction Z3 of the flanges 22 and 23.
Recesses 26 are formed on both sides of each of the flanges 22 and 23 in the first direction Z2. By providing the recesses 26, each of the flanges 22 and 23 has, as side surfaces, a longitudinal side surface 25b connected to the mounting surface 25a and a lateral side surface 25c connected to the longitudinal side surface 25b.
In the embodiment, the longitudinal side surface 25b is formed such that an angle formed by the longitudinal side surface 25b and the mounting surface 25a is a right angle. The lateral side surface 25c is a plane parallel to the mounting surface 25a. However, it is sufficient that the angle formed by the longitudinal side surface 25b and the mounting surface 25a is substantially the right angle, and the angle need not be “90°”. It is sufficient that the lateral side surface 25c is substantially parallel to the mounting surface 25a, and the lateral side surface 25c need not be precisely parallel to the mounting surface 25a.
The coil component 10 includes a first terminal electrode 12a and a second terminal electrode 12b provided on the first flange 22, and a third terminal electrode 12c and a fourth terminal electrode 12d provided on the second flange 23. The first terminal electrode 12a and the third terminal electrode 12c are disposed on the first side with respect to the central axis F in the first direction Z2. The second terminal electrode 12b and the fourth terminal electrode 12d are disposed on the second side with respect to the central axis F in the first direction Z2. The second terminal electrode 12b is located at an equal position to the first terminal electrode 12a in the axial direction Z1. The fourth terminal electrode 12d is located at an equal position to the third terminal electrode 12c in the axial direction Z1.
Each of the terminal electrodes 12a to 12d is formed by processing a metal plate. That is, each of the terminal electrodes 12a to 12d has a base 131 located inside each of the recesses 26 in the first direction Z2. Each of the terminal electrodes 12a to 12d has a side wall 132 disposed along the longitudinal side surface 25b. The side wall 132 is connected to the base 131. Each of the terminal electrodes 12a to 12d has a connection 133 disposed on the lateral side surface 25c. The connection 133 is coupled to the side wall 132. That is, it can be said that the side wall 132 extends in the second direction Z3 from a connected part with the connection 133. Each connection 133 extends substantially in the axial direction Z1.
The first wire 31 and the second wire 41 are wound around the winding core 21 of the core 20. In the embodiment, the first wire 31 and the second wire 41 are wound around the winding core 21 by lap winding. That is, the first wire 31 is directly wound around the winding core 21, and the second wire 41 is wound around the winding core 21 over the first wire 31. The number of windings of the first wire 31 around the winding core 21 is substantially the same as the number of windings of the second wire 41 around the winding core 21.
A method of winding the first wire 31 and the second wire 41 around the winding core 21 need not be lap winding. For example, the first wire 31 and the second wire 41 may be wound around the winding core 21 by bifilar winding, or a region where the first wire 31 and the second wire 41 are wound around the winding core 21 by lap winding and a region where the first wire 31 and the second wire 41 are wound around the winding core 21 by bifilar winding may be both formed.
Each of the wires 31 and 41 has a winding portion 50, a first end 51, a second end 52, a first extended portion 53, and a second extended portion 54. The winding portion 50 is a part of the wires 31 and 41 wound around the winding core 21.
The first end 51 of the first wire 31 is electrically connected to the connection 133 of the first terminal electrode 12a. That is, the first end 51 of the first wire 31 is electrically connected to the connection 133 by a molten ball 60 formed by dissolving a metal constituting the first terminal electrode 12a. That is, the molten ball 60, which becomes solidified as is simply referred to herein as the “molten ball 60”, and electrically connects the first terminal electrode 12a and the first wire 31, contains the metal constituting the first terminal electrode 12a.
The first end 51 of the second wire 41 is electrically connected to the connection 133 of the second terminal electrode 12b. That is, the first end 51 of the second wire 41 is electrically connected to the connection 133 by the molten ball 60 formed by dissolving a metal constituting the second terminal electrode 12b. That is, the molten ball 60 electrically connecting the second terminal electrode 12b and the second wire 41 contains the metal constituting the second terminal electrode 12b.
The second end 52 of the first wire 31 is electrically connected to the connection 133 of the third terminal electrode 12c. That is, the second end 52 of the first wire 31 is electrically connected to the connection 133 by the molten ball 60 formed by dissolving a metal constituting the third terminal electrode 12c. That is, the molten ball 60 electrically connecting the third terminal electrode 12c and the first wire 31 contains the metal constituting the third terminal electrode 12c.
The second end 52 of the second wire 41 is electrically connected to the connection 133 of the fourth terminal electrode 12d. That is, the second end 52 of the second wire 41 is electrically connected to the connection 133 by the molten ball 60 formed by dissolving a metal constituting the fourth terminal electrode 12d. That is, the molten ball 60 electrically connecting the fourth terminal electrode 12d and the second wire 41 contains the metal constituting the fourth terminal electrode 12d.
Next, electrical connections between the terminal electrodes 12a to 12d and the ends of the wires 31 and 41 will be described in detail with reference to
As illustrated in
A surface of the connection 133 is defined as a reference surface 133a. In this case, a gap between the reference surface 133a and the first wire 31 is preferably larger than or equal to a diameter D of the first wire 31. In the embodiment, the gap is larger than the diameter D of the first wire 31.
As illustrated in
Of both ends of the connection 133 in the axial direction Z1, an end closer to the winding core 21 is referred to as an inner end 133b of the connection 133. In this case, the first wire 31 is not in contact with the inner end 133b.
As illustrated in
0<X2≤X1·⅘ (Formula 1)
Accordingly, in the second direction Z3, the bent portion 56 of the first wire 31 is disposed between the tip 61 of the molten ball 60 and the reference surface 133a. Furthermore, in the second direction Z3, the first extended portion 53 of the first wire 31 is disposed on an opposite side of the tip 61 across the bent portion 56.
As illustrated in
An electrical connection state between the second end 52 of the first wire 31 and the third terminal electrode 12c, an electrical connection state between the first end 51 of the second wire 41 and the second terminal electrode 12b, and an electrical connection state between the second end 52 of the second wire 41 and the fourth terminal electrode 12d are equivalent to an electrical connection state between the first end 51 of the first wire 31 and the first terminal electrode 12a. Therefore, a detailed description thereof will be omitted.
Next, an example of a method of electrically connecting the first end 51 of the first wire 31 to the first terminal electrode 12a will be described with reference to
When the temporary fixing is completed in this manner, the metal constituting the first terminal electrode 12a is irradiated with a laser beam, and the metal is melted. At this time, a part of the first end 51 in contact with the first terminal electrode 12a and a periphery of the part are also melted. Thus, the molten ball 60 is created. Then, as illustrated in
When the first terminal electrode 12a is irradiated with the laser beam, heat due to the irradiation of the laser beam is generated in the first terminal electrode 12a. At this time, in a case where the first end 51 of the first wire 31 is as a whole in contact with the first terminal electrode 12a, an amount of heat transferred from the first terminal electrode 12a to the first wire 31 increases, and the first wire 31 is greatly damaged.
On the other hand, in the embodiment, a part of the first end 51 of the first wire 31 is not in contact with the first terminal electrode 12a. Thus, when the molten ball 60 is formed, the amount of heat transferred from the first terminal electrode 12a to the first wire 31 can be reduced. Accordingly, damage to the first wire 31 can be reduced.
In the embodiment, the following effects can be further obtained.
(1) A gap is interposed between each of the terminal electrodes 12a to 12d and the separate portion 51b of the wires 31 and 41. Therefore, when the coil component 10 is solder-mounted on the circuit board, the solder enters between each of the terminal electrodes 12a to 12d and the separate portion 51b of the wires 31 and 41. This can increase a connection strength when the coil component 10 is mounted on the circuit board.
(2) In the embodiment, as illustrated in
(3) In the embodiment, a gap between the reference surface 133a of the connection 133 of each of the terminal electrodes 12a to 12d and the separate portion 51b of the wires 31 and 41 is larger than the diameter D of the wires 31 and 41. Therefore, as compared with a case where the separate portion Mb is close to the reference surface 133a of the connection 133, heat is less likely to transfer from the connection 133 of each of the terminal electrodes 12a to 12d to the wires 31 and 41.
(4) In the embodiment, the separate portion Mb of the wires 31 and 41 are disposed between the tip 61 of the molten ball 60 and the reference surface 133a in the second direction Z3. Accordingly, when the molten ball 60 is formed to electrically connect the wires 31 and 41 to the terminal electrodes 12a to 12d, the occurrence of connection failure can be reduced.
(5) In the embodiment, as illustrated in
(6) In the embodiment, as illustrated in
(7) In the embodiment, the above relational expression (Formula 1) is satisfied. Accordingly, when the molten ball 60 is formed to electrically connect the wires 31 and 41 to the terminal electrodes 12a to 12d, the occurrence of connection failure can be reduced.
The above embodiment can be modified as follows. The embodiment and the following modifications can be implemented in combination with each other so as not to technically contradict.
One of the first end 51 or the second end 52 of the first wire 31 may be in contact with the side walls 132 of the terminal electrode 12a or 12c.
One of the first end 51 or the second end 52 of the second wire 41 may be in contact with the side wall 132 of the terminal electrode 12b or 12d. The separate portion 51b of the first end 51 of the first wire 31 need not be parallel to the reference surface 133a of the connection 133 of the first terminal electrode 12a.
The separate portion 51b of the second end 52 of the first wire 31 need not be parallel to the reference surface 133a of the connection 133 of the third terminal electrode 12c. The separate portion 51b of the first end 51 of the second wire 41 need not be parallel to the reference surface 133a of the connection 133 of the second terminal electrode 12b.
The separate portion 51b of the second end 52 of the second wire 41 need not be parallel to the reference surface 133a of the connection 133 of the fourth terminal electrode 12d. A positional relationship between the separate portion 51b of the first end 51 of the first wire 31 and the reference surface 133a of the connection 133 of the first terminal electrode 12a need not satisfy the relational expression (Formula 1).
A positional relationship between the separate portion 51b of the second end 52 of the first wire 31 and the reference surface 133a of the connection 133 of the third terminal electrode 12c need not satisfy the relational expression (Formula 1).
A positional relationship between the separate portion 51b of the first end 51 of the second wire 41 and the reference surface 133a of the connection 133 of the second terminal electrode 12b need not satisfy the relational expression (Formula 1).
A positional relationship between the separate portion 51b of the second end 52 of the second wire 41 and the reference surface 133a of the connection 133 of the fourth terminal electrode 12d need not satisfy the relational expression (Formula 1).
The first extended portion 53 of the first wire 31 may have a part located on an opposite side of the reference surface 133a across the bent portion 56 in the second direction Z3. The second extended portion 54 of the first wire 31 may have a part located on the opposite side of the reference surface 133a across the bent portion 56 in the second direction Z3.
The first extended portion 53 of the second wire 41 may have a part located on the opposite side of the reference surface 133a across the bent portion 56 in the second direction Z3. The second extended portion 54 of the second wire 41 may have a part located on the opposite side of the reference surface 133a across the bent portion 56 in the second direction Z3.
The bent portion 56 provided at a boundary between the first end 51 and the first extended portion 53 of the first wire 31 may be located on an opposite side of the tip 61 of the molten ball 60 across the reference surface 133a in the second direction Z3.
The bent portion 56 provided at a boundary between the second end 52 and the second extended portion 54 of the first wire 31 may be located on the opposite side of the tip 61 of the molten ball 60 across the reference surface 133a in the second direction Z3.
The bent portion 56 provided at a boundary between the first end 51 and the first extended portion 53 of the second wire 41 may be located on the opposite side of the tip 61 of the molten ball 60 across the reference surface 133a in the second direction Z3.
The bent portion 56 provided at a boundary between the second end 52 and the second extended portion 54 of the second wire 41 may be located on the opposite side of the tip 61 of the molten ball 60 across the reference surface 133a in the second direction Z3.
A gap between at least a part of the separate portion 51b of the first end 51 of the first wire 31 and the reference surface 133a may be smaller than the diameter D of the first wire 31. A gap between at least a part of the separate portion 51b of the second end 52 of the first wire 31 and the reference surface 133a may be smaller than the diameter D of the first wire 31.
A gap between at least a part of the separate portion 51b of the first end 51 of the second wire 41 and the reference surface 133a may be smaller than the diameter D of the first wire 31. A gap between at least a part of the separate portion 51b of the second end 52 of the second wire 41 and the reference surface 133a may be smaller than the diameter D of the first wire 31.
The first wire 31 may be in contact with the inner end 133b of the connection 133 of the first terminal electrode 12a. The first wire 31 may be in contact with the inner end 133b of the connection 133 of the third terminal electrode 12c.
The second wire 41 may be in contact with the inner end 133b of the connection 133 of the second terminal electrode 12b. The second wire 41 may be in contact with the inner end 133b of the connection 133 of the fourth terminal electrode 12d.
If the separate portion 51b can be formed at the first end 51 of the first wire 31, the first end 51 may be electrically connected to the first terminal electrode 12a by a method different from the method of electrically connecting the first end 51 to the first terminal electrode 12a using the molten ball 60. For example, the first end 51 may be electrically connected to the first terminal electrode 12a using solder.
If the separate portion 51b can be formed at the second end 52 of the first wire 31, the second end 52 may be electrically connected to the third terminal electrode 12c by a method different from the method of electrically connecting the second end 52 to the third terminal electrode 12c using the molten ball 60. For example, the first end 51 may be electrically connected to the first terminal electrode 12a using solder.
If the separate portion 51b can be formed at the first end 51 of the second wire 41, the second end 52 may be electrically connected to the second terminal electrode 12b by a method different from the method of electrically connecting the first end 51 to the second terminal electrode 12b using the molten ball 60. For example, the first end 51 may be electrically connected to the first terminal electrode 12a using solder.
If the separate portion 51b can be formed at the second end 52 of the second wire 41, the second end 52 may be electrically connected to the fourth terminal electrode 12d by a method different from the method of electrically connecting the second end 52 to the fourth terminal electrode 12d using the molten ball 60. For example, the first end 51 may be electrically connected to the first terminal electrode 12a using solder.
If a part of the ends of the wires 31 and 41 is spaced apart from the connection 133 of the terminal electrode, the remaining part of the ends of the wires 31 and 41 may be in contact with the connection 133. In the coil component, only one wire may be wound around the core.
The coil component need not be a common mode choke coil.
Number | Date | Country | Kind |
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2020-188962 | Nov 2020 | JP | national |