JP7495835B2 - Coil device - Google Patents

Description

The present invention relates to a coil device that is used, for example, as an inductor.

For example, the coil device described in Patent Document 1 is known as a coil device used as an inductor, etc. The coil device described in Patent Document 1 has a coil, a terminal to which the end of the coil is connected, and a core that covers the coil and the connection part of the terminal. In the coil device described in Patent Document 1, the connection part is disposed inside the core, so that it is possible to protect the connection part from external factors such as external forces.

In the coil device described in Patent Document 1, if a coil made of flatwise wound rectangular wire is to be used, the ends of the coil must be twisted in order to connect them to terminals. However, in this case, there is a risk that the inductance characteristics will vary from product to product, reducing product reliability.

JP 2007-165779 A

The present invention was made in consideration of these circumstances, and its purpose is to provide a highly reliable coil device.

In order to achieve the above object, a coil device according to the present invention comprises:
A coil made by winding a rectangular wire flatwise;
a terminal having a connection portion with a holding surface for holding an end of the coil;
a core that covers the coil and the connection portion,
The holding surface extends parallel to the winding axis of the coil.

In the coil device according to the present invention, the holding surface of the terminal extends parallel to the winding axis of the coil. In a coil made by flatwise winding rectangular wire, the long side surface of the end also extends parallel to the winding axis. Therefore, when the end is pulled out from the winding portion of the coil, it is possible to align the orientation of the long side surface and the holding surface of the connection wire portion without twisting the end. Therefore, it is possible to hold the end of the coil on the holding surface without twisting it, which prevents variation in the inductance characteristics of the coil device and realizes a highly reliable coil device.

Preferably, the holding surface faces the side surface of the core. With this configuration, when performing laser welding on the connection portion (holding surface), for example, it becomes easier to irradiate the laser from the side of the coil device, making manufacturing easier.

Preferably, the end of the coil is bent into a substantially L-shape. This configuration makes it possible to easily position the long side of the end of the coil facing the side of the core. Therefore, when the end of the coil is held by the holding surface of the connection section, the holding surface faces the side of the core, making it easier to irradiate the laser from the side of the coil device.

Preferably, the connection wire portion is arranged outside an imaginary line that is parallel to the side of the core and tangent to the outer circumference of the coil. With this configuration, it is possible to arrange the connection wire portion at a position sufficiently separated from the coil. Therefore, when laser welding is performed on the connection wire portion, it is possible to prevent a part of the laser from being irradiated onto the winding portion of the coil, and to reduce damage to the winding portion of the coil. It is also possible to prevent a part of the laser from being irradiated onto the core, and to reduce damage to the core.

Preferably, when viewed from a direction perpendicular to the side surface of the core, the connection wire portion and the remaining portion of the terminal excluding the connection wire portion are arranged in a misaligned position. With this configuration, it is possible to arrange the connection wire portion in a direction parallel to the side surface of the core and at a position sufficiently separated from the coil, and the above-mentioned effect can be obtained when laser welding is performed on the connection wire portion.

Preferably, the terminal has a fixing portion disposed inside the core, and an opening is formed in the fixing portion. With this configuration, the material forming the core can enter inside the opening, and the terminal can be fixed to the core with sufficient fixing strength.

Preferably, the core contains magnetic particles and a resin binder. With this configuration, a coil device with good inductance characteristics can be realized.

Preferably, the terminals are a pair, and the holding surface of one terminal and the holding surface of the other terminal face in the same direction. With this configuration, when performing laser welding on each connection part (each holding surface) of each terminal, for example, it becomes easier to irradiate the laser onto each connection part (each holding surface), making manufacturing easier.

Preferably, the terminals are a pair, and the connection wire portion of one terminal and the connection wire portion of the other terminal are arranged diagonally across the coil. With this configuration, it is possible to hold either end of the coil by a terminal arranged facing the side of the core in a state where it is pulled out straight without bending it into a roughly L-shape. This makes it easier to irradiate the terminal with a laser from the side of the coil device.

FIG. 1 is a perspective view of a coil device according to a first embodiment of the present invention. FIG. 2 is a perspective view of the first core shown in FIG. FIG. 3 is a perspective view of the coil shown in FIG. FIG. 4 is a perspective view of the terminal shown in FIG. FIG. 5 is a perspective view of the coil device shown in FIG. 1 as seen from a different angle. FIG. 6A is a diagram showing a method for manufacturing the coil device shown in FIG. FIG. 6B is a diagram showing a process subsequent to that of FIG. 6A. FIG. 6C is a diagram showing a process subsequent to that of FIG. 6B. FIG. 6D is a diagram showing a process subsequent to that of FIG. 6C. FIG. 6E is a diagram showing a process subsequent to that of FIG. 6D. FIG. 7 is a perspective view of a coil device according to a second embodiment of the present invention.

The present invention will now be described with reference to the embodiments shown in the drawings.

First embodiment As shown in FIG. 1, the inductor 1 according to the first embodiment of the present invention has a substantially rectangular parallelepiped shape and includes a coil 2, terminals 4a, 4b, a first core 5, and a second core 6. The inductor 1 has a shape in which the first core 5 and the second core 6 are combined in the Z-axis direction. The top surface of the inductor 1 is formed on the first core 5 side, and the bottom surface (mounting surface) of the inductor 1 is formed on the second core 6 side. That is, the first core 5 has an outer surface opposite to the mounting surface. The second core 6 is shown by a virtual line to facilitate understanding of the internal configuration of the inductor 1. In addition, in FIG. 2 to FIG. 6D, each of the above configurations is illustrated upside down to facilitate understanding.

The dimensions of the inductor 1 are not particularly limited, but its width in the X-axis direction is preferably 2 to 20 mm, its width in the Y-axis direction is preferably 2 to 20 mm, and its width in the Z-axis direction is preferably 1 to 10 mm.

As shown in FIG. 2, the first core 5 has a base portion 50 and a columnar portion 51 formed on the surface (upper surface) of the base portion 50. When the inductor 1 is placed so that the mounting surface faces downward, as shown in FIG. 1, the upper surface of the base portion 50 faces downward from the inductor 1.

The first core 5 is made of synthetic resin in which ferrite particles or metal magnetic particles are dispersed. However, the material constituting the first core 5 is not limited to this, and it may be made of synthetic resin that does not contain these particles. Examples of ferrite particles include Ni-Zn ferrite and Mn-Zn ferrite. Examples of metal magnetic particles include, but are not limited to, Fe-Ni alloy powder, Fe-Si alloy powder, Fe-Si-Cr alloy powder, Fe-Co alloy powder, Fe-Si-Al alloy powder, and amorphous iron.

The synthetic resin contained in the first core 5 is not particularly limited, but preferred examples include epoxy resin, phenolic resin, polyester resin, polyurethane resin, polyimide resin, and silicone resin.

The base portion 50 has a substantially rectangular parallelepiped shape (substantially flattened shape) and its surface (top surface) is flat. The top surface of the base portion 50 is covered by the second core 6 shown in FIG. 1. A recess 155 is formed on each side surface (each end) of the base portion 50 in the X-axis direction. The depth of the recess 155 in the X-axis direction is not particularly limited, but is, for example, approximately the same as or greater than the plate thickness of the terminals 4a and 4b. The width of the recess 155 in the Y-axis direction is approximately 1/2 to 2/3 of the width of the base portion 50 in the Y-axis direction, and is approximately equal to the width of the terminals 4a and 4b in the Y-axis direction shown in FIG. 1.

The columnar portion 51 is integrally formed at approximately the center of the base portion 50 and extends in the Z-axis direction. The coil (air-core coil) 2 shown in FIG. 1 is disposed (inserted or wound) in the columnar portion 51. Therefore, the diameter of the columnar portion 51 is smaller than the inner diameter of the coil 2. The columnar portion 51 has a cylindrical shape and its height is greater than the height of the coil 2. By providing the first core 5 with the columnar portion 51, it is possible to sufficiently ensure the effective permeability of the first core 5 in the region inside the coil 2, and the inductance characteristics of the inductor 1 can be improved.

As shown in FIG. 3, the coil 2 is an air-core coil, and is formed by flatwise winding the wire 3 made of rectangular wire. In this embodiment, the coil 2 is α-wound. The long side surface (width direction surface) of the wire 3 forms the inner or outer circumferential surface of the coil 2, and the width direction of the wire 3 is approximately parallel to the winding axis direction of the coil 2. The short side surface (edge side surface) of the wire 3 faces the Z-axis direction. The coil 2 is placed on the upper surface of the base part 50 shown in FIG. 5.

Materials constituting the wire 3 include, for example, good conductors such as copper and copper alloys, silver, and nickel, but are not particularly limited as long as they are conductive materials. An insulating coating is applied to the surface of the wire 3. The resin constituting the insulating coating is not particularly limited, but for example, epoxy-modified acrylic resin is used.

One end of the wire 3 (wire end 3a) constitutes one end of the coil 2, and the other end of the wire 3 (wire end 3b) constitutes the other end of the coil 2. The wire end 3a of the wire 3 is bent into a roughly L-shape and is drawn out linearly from the upper end of the coil 2 (the wound portion of the coil 2) along the Y-axis direction to the outside. The wire end 3b of the wire 3 is bent into a roughly L-shape and is drawn out linearly from the lower end of the coil 2 (the wound portion of the coil 2) along the Y-axis direction to the outside.

Both wire ends 3a and 3b are pulled out in the same direction (Y-axis direction) without being twisted. The tip of wire end 3a and the tip of wire end 3b extend in opposite directions along the X-axis direction.

As shown in FIG. 4, the terminals 4a and 4b are formed in mirror symmetry with respect to the YZ plane, and as shown in FIG. 5, they are arranged (placed) on the upper surface of the base portion 50 at a predetermined interval in the X-axis direction. The terminal 4a is arranged on one side of the base portion 50 in the X-axis direction, and the terminal 4b is arranged on the other side of the base portion 50 in the X-axis direction. The terminals 4a and 4b are formed, for example, by machining a metal plate, but the method of forming the terminals 4a and 4b is not limited to this.

As shown in FIG. 4, the terminals 4a and 4b have a first mounting portion 41, a second mounting portion 42, a connection portion 43, an implementation portion 44, a connection portion 45, a notch portion 46, and a fixing hole 47.

The mounting portion 44 is fixed to the bottom surface of the second core 6 shown in FIG. 1. The mounting portion 44 has a predetermined width in the Y-axis direction, and is fixed to a region extending from one end of the bottom surface of the second core 6 in the Y-axis direction to the other end. The mounting portion 44 also has a predetermined width in the X-axis direction, and is fixed to an end of the bottom surface of the second core 6 in the X-axis direction. The mounting portion 44 is connected to a circuit board (not shown) by solder, conductive adhesive, or the like.

The connection portion 45 is integrally connected to the mounting portion 44 and extends in a direction substantially perpendicular to the mounting portion 44. The connection portion 45 is a portion that connects the mounting portion 44 to the placement portions 41 and 42, and is fixed to the outer surface of the second core 6 shown in FIG. 1. The connection portion 45 extends along the outer surface of the second core 6 toward the opposite side (Z-axis negative direction) to the first core 5. The connection portion 45 of the terminal 4a and the connection portion 45 of the terminal 4b are disposed opposite to each other in the X-axis direction. When the mounting portion 44 is connected to a circuit board (not shown) by solder, a solder fillet is formed in part of the connection portion 45. That is, the connection portion 45 also functions as a solder fillet forming portion.

The first mounting portion 41 and the second mounting portion 42 are integrally connected to the end of the connection portion 45 in the Z-axis direction, and extend in a direction approximately perpendicular to the connection portion 45 (the same direction as the extension direction of the mounting portion 44: the X-axis direction). The mounting portions 41 and 42 have a surface approximately parallel to the upper surface of the first core 5 (base portion 50), and face the mounting portion 44 in the Z-axis direction. The mounting portions 41 and 42 are placed on the upper surface of the base portion 50 (see FIG. 5), and are sandwiched between the first core 5 and the second core 6.

The mounting parts 41, 42 arranged on the base part 50 are covered by the first core 5 (base part 50) and the second core 6, so that the terminals 4a, 4b can be fixed to the cores 5, 6 via the mounting parts 41, 42. In other words, the mounting parts 41, 42 function as fixing parts for fixing the terminals 4a, 4b to the cores 5, 6.

As shown in FIG. 4, the first mounting portion 41 is formed at one end of the terminals 4a and 4b in the Y-axis direction, and the second mounting portion 42 is formed at the other end of the terminals 4a and 4b in the Y-axis direction. The first mounting portion 41 and the second mounting portion 42 are arranged at a predetermined interval in the Y-axis direction, and a notch portion 46 is formed between each of the mounting portions 41 and 42 to separate them. As shown in FIG. 1, the notch portion 46 is formed at a position where at least the terminals 4a and 4b are exposed to the outside of the first core 5 and the second core 6, and in the example shown in FIG. 4, it extends from the tip of the mounting portion 41 and 42 to the lower end of the connection portion 45. By providing the notch portion 46 to the terminals 4a and 4b, it becomes easier to bend the terminals 4a and 4b at the intersection between the mounting portions 41 and 42 and the connection portion 45.

The connection wire portion 43 is integrally formed at one end of the first mounting portion 41 in the Y-axis direction. The width of the connection wire portion 43 in the X-axis direction is narrower than the width of the first mounting portion 41 in the X-axis direction, which allows the connection wire portion 43 to be made smaller. The end of the coil 2 shown in FIG. 3 is connected to the connection wire portion 43. The connection wire portion 43 of the terminal 4a and the connection wire portion 43 of the terminal 4b are arranged facing the same direction (Y-axis direction). Therefore, when performing laser welding on each connection wire portion 43, 43, for example, it becomes easier to irradiate the laser from the positive Y-axis direction side to each connection wire portion 43, 43, which facilitates manufacturing.

As shown in FIG. 5, the connection part 43 of the terminal 4b is arranged on the outside (X-axis positive side) of the imaginary line L that is parallel to the side of the second core 6 (FIG. 1) (the side that intersects perpendicularly to the X-axis and to which the terminal 4b is fixed) and that is tangent to the outer circumference of the coil 2. In the illustrated example, the imaginary line L is parallel to the direction in which the wire end 3b of the wire 3 is drawn out and passes over the wire end 3b. Although detailed illustration is omitted, the same is true for the connection part 43 of the terminal 4a, which is arranged on the outside (X-axis negative side) of the imaginary line that is parallel to the side of the second core 6 (the side that intersects perpendicularly to the X-axis and to which the terminal 4a is fixed) and that is tangent to the outer circumference of the coil 2.

When viewed from a direction perpendicular to the side surface of the second core 6 (FIG. 1) (the side surface to which the terminal 4a is fixed), the connection portion 43 of the terminal 4a and the remaining portions of the terminal 4a excluding the connection portion 43 (the mounting portions 41, 42, the mounting portion 44, the connection portion 45, etc.) are positioned with a misalignment in the Y-axis direction. Similarly, when viewed from a direction perpendicular to the side surface of the second core 6 (the side surface to which the terminal 4b is fixed), the connection portion 43 of the terminal 4b and the remaining portions of the terminal 4b excluding the connection portion 43 (the mounting portions 41, 42, the mounting portion 44, the connection portion 45, etc.) are positioned with a misalignment in the Y-axis direction.

As shown in FIG. 4, the connection section 43 has a fixed piece 43a and a bent piece 43b. The fixed piece 43a faces the bent piece 43b in the Y-axis direction and is integrally formed with one end of the first mounting section 41 in the Y-axis direction. The fixed piece 43a is bent upward with the one end of the first mounting section 41 in the Y-axis direction as a bending point (fulcrum).

The length in the Z-axis direction of the fixed piece 43a of terminal 4a is longer than the length in the Z-axis direction of the fixed piece 43a of terminal 4b, and is also longer than the length in the Z-axis direction of the bent piece 43b of terminal 4a. The length in the Z-axis direction of the fixed piece 43a of terminal 4b is approximately equal to the length in the Z-axis direction of the bent piece 43b of terminal 4b.

The bent piece 43b is integrally formed at one end of the fixed piece 43a in the Z-axis direction, and is bent downward with this end as a bending point (fulcrum). Both the fixed piece 43a and the bent piece 43b are formed to extend in the Z-axis direction, and are arranged perpendicular to the upper surface of the base part 50. When the inductor 1 is manufactured, a laser is irradiated onto the outer surface of the bent piece 43b in the Y-axis direction, and this surface functions as the laser irradiation surface.

As shown in FIG. 5, the connection part 43 of the terminal 4a sandwiches and holds the wire end 3a of the wire 3 between its fixed piece 43a and bent piece 43b. Since the wire end 3a of the wire 3 is pulled out from the upper end of the coil 2, the connection part 43 of the terminal 4a holds the wire end 3a above the upper surface of the base part 50. The connection part 43 of the terminal 4a is embedded inside the second core 6. Note that before sandwiching the wire end 3a, the bent piece 43b of the terminal 4a is bent perpendicular to the fixed piece 45a and extends along the Y-axis direction.

The connection part 43 of the terminal 4b sandwiches and holds the wire end 3b of the wire 3 between its fixed piece 43a and bent piece 43b. Since the wire end 3b of the wire 3 is pulled out from the lower end of the coil 2, the connection part 43 of the terminal 4b holds the wire end 3b while placed on the upper surface of the base part 50. The connection part 43 of the terminal 4b is sandwiched between the first core 5 and the second core 6. Note that before sandwiching the wire end 3b, the bent piece 43b of the terminal 4b is bent perpendicularly to the fixed piece 45a and extends along the Y-axis direction.

As shown in Figures 4 and 5, the connection part 43 is provided with a holding surface 430 that holds the end of the coil 2. The holding surface 430 corresponds to the contact surface between the fixed piece 43a and the long side surface of the wire ends 3a and 3b, or the contact surface between the bent piece 43b and the long side surface of the wire ends 3a and 3b. The holding surface 430 of the connection part 43 of terminal 4a and the holding surface 430 of the connection part 43 of terminal 4b face in the same direction (Y-axis direction).

When the long side surfaces of the wire ends 3a and 3b of the wire 3 are held by the connection section 43, the holding surface 430 is disposed approximately parallel to the side surface of the second core 6 shown in FIG. 1 (the side surface that intersects perpendicularly with the Y-axis and to which the terminals 4a and 4b are not fixed) and is disposed approximately perpendicular to the upper surface of the base section 50. However, the holding surface 430 may be disposed at a slight incline with respect to the above-mentioned side surface of the second core 6.

The holding surface 430 is arranged so as to be approximately parallel to the winding axis of the coil 2. The clamping direction when the wire ends 3a, 3b of the wire 3 are clamped between the fixed piece 43a and the bent piece 43b is approximately perpendicular to the winding axis of the coil 2 and approximately perpendicular to the holding surface 430 (the normal direction of the holding surface 430).

The holding surface 430 (contact surface) of the wire ends 3a, 3b in the fixed piece 43a, the holding surface 430 (contact surface) of the wire ends 3a, 3b in the bent piece 43b, and the long side surfaces of the wire ends 3a, 3b are arranged approximately parallel to each other, and all face the side surface of the second core 6 (the side surface perpendicular to the Y-axis).

As shown in FIG. 4, the fixing holes (openings) 47 are formed in each of the first mounting portion 41 and the second mounting portion 42. When the second core 6 is formed, the material forming the second core 6 (a mixture containing magnetic powder and binder resin) enters the fixing holes 47 inside the mold, making it possible to firmly fix the terminals 4a and 4b to the second core 6.

As shown in FIG. 5, the connection part 43 and the coil 2 are arranged on approximately the same plane of the base part 50. In this embodiment, the connection part 43 of the terminals 4a, 4b is arranged above the first core 5 (base part 50) around the connection part 43, and the second core 6 shown in FIG. 1 is arranged above the connection part 43. Therefore, it is possible to arrange the connection part 43 between the first core 5 and the second core 6, which effectively protects the connection part 43 from external factors such as external forces and prevents the occurrence of open failures. In addition, by arranging the connection part 43 on the first core 5, it is possible to prevent the connection part 43 from shifting in position when the second core 6 is arranged on the connection part 43.

As shown in Figures 1 and 5, the second core 6 is formed so as to cover the upper surface of the base portion 50 together with the coil 2. The second core 6 is formed, for example, by inserting a temporary assembly in which the coil 2, with the terminals 4a, 4b connected to each end thereof, and the first core 5 are combined into a mold, and then performing injection molding. However, a preformed core (temporary molded core) may also be used as the second core 6. The second core 6 may be made of the same material as the first core 5, or may be made of a different material. The second core 6 may also be made of resin only.

When the first core 5 is combined with the second core 6, the coil 2 and parts of the terminals 4a and 4b (the mounting parts 41 and 42 and the connection parts 43) are covered by the second core 6. The first core 5 and the second core 6 are joined on approximately the same plane.

Next, a method for manufacturing the inductor 1 will be described with reference to Figures 6A to 6E. In the method of this embodiment, first, a conductive plate such as a metal plate (for example, a Sn-plated metal plate) is punched into the shape shown in Figure 6A. As shown in the figure, the conductive plate after punching has terminals 4a and 4b formed thereon, which are connected to the frame 7 via a connection portion 45.

Next, terminals 4a and 4b are connected to each end of the coil 2 (wire ends 3a and 3b of the wire 3) shown in FIG. 3. More specifically, the coil 2 is placed between terminals 4a and 4b, the wire ends 3a and 3b are sandwiched (held) between the fixed portion 43a and the bent piece 43b, and the wire ends 3a and 3b are connected to the connecting portion 43.

Next, as shown in FIG. 6B, the coil 2 having the terminals 4a, 4b fixed to each end is combined with the first core 5 shown in FIG. 2 to form a temporary assembly. More specifically, the columnar portion 51 of the first core 5 is inserted inside the coil 2, and the coil 2 is placed on the upper surface of the base portion 50. The mounting portions 41, 42 of the terminals 4a, 4b are placed on the upper surface of the base portion 50. A preformed core (temporary molded core) is used as the first core 5. A fluid material is used as the material for the first core 5, and a composite magnetic material using a thermoplastic resin or a thermosetting resin as a binder is used.

Before or after constructing the temporary assembly (i.e., in the state shown in FIG. 6A or FIG. 6B), laser welding is performed on the connection portion 43. Laser welding is performed, for example, by irradiating a laser from the side of the connection portion 43 (in a direction perpendicular to the bent piece 43b) toward the bent piece 43b. A laser ball (not shown) is formed in the portion irradiated with the laser.

Next, the temporary assembly shown in FIG. 6B is inserted into a mold, and the second core 6 is formed in the mold by injection molding. At this time, the connection parts 45 of the terminals 4a, 4b are left exposed from the mold. During injection molding, a mixture containing magnetic powder and binder resin is fluidized by heating or the like, injected into the mold, and solidified by cooling or the like to obtain the second core 6 shown in FIG. 6C. At this time, the mixture enters the fixing holes 47 of the terminals 4a, 4b, so that the terminals 4a, 4b can be fixed to the second core 6 with sufficient fixing strength.

In the example shown in FIG. 6C, a step 60 is formed on the surface of the second core 6, spanning its side and bottom surfaces. A portion of the step 60 formed on the bottom surface of the second core 6 can accommodate the mounting portion 44 (FIG. 4) of the terminals 4a and 4b, and a portion of the step 60 formed on the side surface of the second core 6 can accommodate the connection portion 45 of the terminals 4a and 4b.

Next, as shown in Fig. 6D, the frame 7 shown in Fig. 6C is cut and removed with a cutting tool, and as shown in Fig. 6E, the remaining portion (connection portion 45) is fixed to the step portion 60. More specifically, as shown in Fig. 6E, the connection portion 45 of the terminals 4a, 4b is bent substantially vertically from the state shown in Fig. 6D, and the connection portion 45 is fixed to a part of the step portion 60 formed on the side surface of the second core 6. In this state, the tip portion of the connection portion 45 is bent substantially vertically and fixed to a part of the step portion 60 formed on the bottom surface of the second core 6. In this manner, the inductor 1 of this embodiment can be obtained.

In the inductor 1 according to this embodiment, the holding surface 430 of the connection wire portion 43 extends parallel to the winding axis of the coil 2. In the coil 2 formed by flatwise winding a rectangular wire, the long side surface of the end (wire ends 3a, 3b of the wire 3) also extends parallel to the winding axis. Therefore, when the wire ends 3a, 3b are pulled out from the winding portion of the coil 2, it is possible to align the long side surface and the holding surface 430 of the connection wire portion 43 without twisting the wire ends 3a, 3b. Therefore, it is possible to hold the wire ends 3a, 3b on the holding surface 430 without twisting them, and it is possible to prevent variation in the inductance characteristics of the inductor 1 and realize a highly reliable inductor 1.

In addition, in this embodiment, the holding surface 430 faces the side surface of the second core 6 (the side surface perpendicular to the Y-axis). Therefore, when performing laser welding on the connection portion 43 (holding surface 430), for example, it becomes easier to irradiate the laser from the side of the inductor 1 along the Y-axis direction, which makes manufacturing easier.

In addition, in this embodiment, the wire ends 3a and 3b are bent into a roughly L-shape. This makes it easy to make the long side surfaces of the wire ends 3a and 3b face the side surfaces of the second core 6 (the side surfaces perpendicular to the Y-axis). Therefore, when the wire ends 3a and 3b are held by the holding surface 430 of the connection section 43, the holding surface 430 is positioned facing the side surfaces of the second core 6 (the side surfaces perpendicular to the Y-axis), making it easier to irradiate the laser from the side of the inductor 1 along the Y-axis direction.

In addition, in this embodiment, the connection part 43 is arranged outside the imaginary line L that is parallel to the side of the second core 6 (the side that intersects perpendicularly to the X-axis) and touches the outer periphery of the coil 2. This makes it possible to arrange the connection part 43 at a position sufficiently separated from the coil 2. Therefore, when laser welding is performed on the connection part 43, it is possible to prevent part of the laser from being irradiated onto the winding part of the coil 2, thereby reducing damage to the winding part of the coil 2. In addition, it is possible to prevent part of the laser from being irradiated onto the first core 5, thereby reducing damage to the first core 5.

In addition, in this embodiment, when viewed from a direction perpendicular to the side surface of the second core 6 (the side surface perpendicular to the X-axis to which the terminals 4a and 4b are fixed), the connection portion 43 and the remaining portions of the terminals 4a and 4b excluding the connection portion 43 (the mounting portions 41 and 42, the mounting portion 44, and the connection portion 45) are misaligned. This makes it possible to position the connection portion 43 in a direction parallel to the side surface of the second core 6 and at a sufficient distance from the coil 2, and the above-mentioned effect can be obtained when laser welding the connection portion 43.

In addition, in this embodiment, the cores 5 and 6 contain magnetic particles and a resin binder. This allows for the realization of an inductor 1 with good inductance characteristics.

In addition, in this embodiment, the holding surface 430 of terminal 4a and the holding surface 430 of terminal 4b face in the same direction (the positive Y-axis direction). Therefore, when performing laser welding on the connection portion 43 (holding surface 430) of terminals 4a and 4b, for example, it becomes easier to irradiate the laser onto the connection portion 43 (holding surface 430), which facilitates manufacturing.

Second Embodiment The inductor 101 according to a second embodiment of the present invention is similar to the first embodiment described above, except for the following differences. In the following, parts common to the first embodiment are given the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 7, inductor 101 differs from inductor 1 in the first embodiment in that inductor 101 has coil 102 instead of coil 2 and has terminal 104b instead of terminal 4b. Terminal 104b differs from terminal 4b in the first embodiment (FIG. 4) in that connecting wire portion 43 is connected to the end of the other end of second mounting portion 42 in the Y-axis direction. Bent piece 45b of connecting wire portion 43 faces the other side of second core 6 in the Y-axis direction.

In the coil 102, one end (wire end 3a) is drawn out toward the side of the second core 6 (the side perpendicular to the Y axis) in the positive direction of the Y axis. The tip of wire end 3a is bent in a roughly L-shape and extends along the X axis. The other end (wire end 3b) is drawn out toward the negative direction of the X axis, toward the side of the second core 6 (the side perpendicular to the X axis). The tip of wire end 3b is not bent and extends straight along the X axis.

In this embodiment, the same effect as in the first embodiment can be obtained. In addition, in this embodiment, the connection wire portion 43 of the terminal 4a and the connection wire portion 43 of the terminal 104b are arranged diagonally across the coil 102. Therefore, the wire end 3b can be held by the connection wire portion 43 of the terminal 104b arranged facing the side surface of the second core (the side surface perpendicular to the Y axis) in a state where it is pulled out straight without being bent into an approximately L shape. Therefore, it becomes easier to irradiate the laser to the connection wire portion 43 of the terminal 104b from the side of the inductor 101 along the Y axis direction.

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.

In each of the above embodiments, examples of application of the present invention to inductors have been shown, but the present invention may also be applied to coil devices other than inductors.

In each of the above embodiments, the winding shape of the wire 3 is a circular spiral, but it may be, for example, an elliptical spiral or a square spiral.

In the first embodiment, a portion of the top surface or side surface of the first core 5 may be covered by the second core 6. The same applies to the second embodiment.

In the first embodiment, the connection portions 45 of the terminals 4a and 4b may be bent toward the first core 5. The same applies to the second embodiment.

In each of the above embodiments, the core portion of the inductor 1 is composed of two cores, the first core 5 and the second core 6, but the core portion of the inductor 1 may be composed of only one core. In this case, the core may be formed by powder molding, injection molding, or the like.

In the above embodiments, the holding surface 430 of each connection portion 43 (fixed piece 43a and bent piece 43b) of terminals 4a and 4b faces the Y-axis direction, but it may face the X-axis direction. That is, the holding surface 430 of the connection portion 43 (fixed piece 43a and bent piece 43b) may be arranged so as to be approximately parallel to the side surface of the second core 6 (the side surface that intersects perpendicularly to the X-axis and to which terminals 4a and 4b are fixed).

In each of the above embodiments, the connecting wire portion 43 is not limited to the configuration shown in FIG. 4, and the shape may be changed as appropriate. For example, the bent piece 43b may be omitted from the connecting wire portion 43.

1,101...inductor (coil device)
2, 102... Coil 3... Wire 3a, 3b... Wire end 4a, 4b, 104b... Terminal 41... First mounting portion 42... Second mounting portion 43... Wire connection portion 43a... Fixing piece 43b... Bent piece 430... Holding surface 44... Mounting portion 45... Connection portion 46... Notch portion 47... Fixing hole 5... First core 50... Base portion 51... Columnar portion 52... Recess 6... Second core 60... Step portion 7... Frame

Claims (10)

A coil made by winding a rectangular wire flatwise;
a terminal having a connection portion with a holding surface for holding an end of the coil;
a core having a mounting surface capable of facing a mounting board and a first side surface perpendicular to the mounting surface, the core covering the coil and the connection portion,
The holding surface extends substantially parallel to a winding axis of the coil ,
the terminal has a mounting portion disposed along the mounting surface, a connection portion connected to the mounting portion and disposed along the first side surface, a placement portion connected to the connection portion and disposed inside the core, and the connecting wire portion has the holding surface rising from the placement portion toward the mounting surface,
A coil device in which, when viewed from a direction perpendicular to the holding surface, the holding surface rises at a position between the outer periphery of the coil and the first side surface . The coil device according to claim 1 , wherein the holding surface faces a second side surface of the core that is perpendicular to the first side surface. The coil device according to claim 1 or 2, wherein the end of the coil is bent into a substantially L-shape. 4. The coil device according to claim 1, wherein the connection portion is disposed outside an imaginary line that is parallel to the first side surface and tangent to an outer periphery of the coil. The coil device according to any one of claims 1 to 4, wherein, when viewed from a direction perpendicular to the first side, the connection portion and the remaining portion of the terminal excluding the connection portion are positioned out of position. The terminal has a fixing portion disposed inside the core,
The coil device according to any one of claims 1 to 5, wherein an opening is formed in the fixing portion. The coil device according to any one of claims 1 to 6, wherein the core contains magnetic particles and a resin binder. A pair of the terminals is provided.
8. The coil device according to claim 1, wherein the holding surface of one of the terminals and the holding surface of the other of the terminals face in the same direction. A pair of the terminals is provided.
8. The coil device according to claim 1, wherein the connection portion of one of the terminals and the connection portion of the other of the terminals are arranged diagonally across the coil. the ends of the coil include a first end and a second end,
the terminal includes a first terminal and a second terminal,
the core has a third side surface opposite the first side surface,
the first terminal has a first holding surface that holds the first end,
the second terminal has a second holding surface that holds the second end,
the first end and the second end are drawn out in a first direction perpendicular to the winding axis and are bent so as to move away from each other in a second direction perpendicular to the winding axis and the first direction,
When viewed from the first direction, the first end is connected to the first holding surface between an outer periphery of the coil and the first side surface,
A coil device as described in any one of claims 1 to 9, wherein, when viewed from the first direction, the second end is connected to the second retaining surface between the outer periphery of the coil and the third side surface.