Inductor, electrical device, and coil

Abstract

This inductor (1) comprises a conductor portion (10). The conductor portion (10) is a member that includes an end portion (20), and the member generates inductance. The end portion (20) of the conductor portion (10) has a flat plate shape with two main surfaces (22) facing each other. The end portion (20) also has a hole (24) penetrating in the thickness direction. On one main surface (22) of the end portion (20) of the conductor portion (10), an uneven region (30) with an uneven structure (30a) is formed around the hole (24).

Description

Inductor, Electrical Equipment, and Coil

[0001] The present invention relates to an inductor, electrical equipment, and a coil.

[0002] In an inductor having a conductor portion that generates an inductor such as a coil, there are cases where the surface of the end portion of the conductor portion such as a coil is connected to the surface of another conductive member (referred to as a connection target) by screwing to achieve electrical connection. For example, in Patent Document 1 below, a hole (20b) for screwing is provided in a connection terminal portion (17) which is an end portion of a winding coil (15). The connection terminal portion (17) is attached to a substrate or the like by a screw (26).

[0003] Japanese Patent Application Laid-Open No. 2009-218531

[0004] However, when the surface of the end portion of the conductor portion such as a coil and the surface of the connection target are brought into contact by screwing, there are cases where one of the surfaces is not a flat surface, such as when there is a twist on one of the surfaces. In this case, it may be difficult for the entire surface of one side to contact the other side compared to the case where both surfaces are flat surfaces. Therefore, there is room for improvement to ensure sufficient contact between the surface of the end portion of the conductor portion such as a coil and the surface of the connection target.

[0005] The present invention has been made in view of the above problems, and provides an inductor or a coil in which the surface of the end portion of a conductor portion such as a coil can be in good contact with the surface of a connection target.

[0006] The inductor of the present invention includes an end portion, has a conductor portion that generates inductance, the end portion is in a flat plate shape having two opposing main surfaces, the end portion has a hole penetrating in the thickness direction, and on one of the main surfaces of the end portion, a concavo-convex region having a concavo-convex structure is formed around the hole.

[0007] The coil of the present invention is a coil including an end portion, the end portion is in a flat plate shape having two opposing main surfaces, the end portion has a hole penetrating in the thickness direction, and on one of the main surfaces of the end portion, a concavo-convex region having a concavo-convex structure is formed around the hole.

[0008] Because the main surface of the end of the conductor has an uneven structure, when the end of the conductor is pressed against the surface to be connected by tightening the screw, the protrusions formed in the uneven region bite into the surface to be connected and make contact with the surface to be connected.

[0009] According to the inductor or coil of the present invention, since an uneven region is formed on the main surface of the end of the conductor portion including the coil, sufficient contact between the uneven region and the surface to be connected can be ensured. This allows the end surface of the conductor portion to make good contact with the surface to be connected.

[0010] The aforementioned objectives, as well as other objectives, features, and advantages, will become even clearer from the preferred embodiments described below and the accompanying drawings.

[0011] This is a schematic perspective view showing an example of an inductor according to the first embodiment of the present invention. Figure 2(a) is an enlarged view of the vicinity of the end of the conductor portion in Figure 1. Figure 2(b) is a longitudinal cross-sectional view of the vicinity of the end of the conductor portion in Figure 2(a). This is a schematic plan view of the end of the conductor portion according to the first embodiment, as seen from the connection surface side of the conductor portion. Figure 4(a) is a cross-sectional view of the cross section along the dashed line in Figure 3, as seen in the direction of arrow IV-IV. Figure 4(b) is an enlarged view of the area within the frame indicated by the dashed line in Figure 4(a). Figure 5(a) is a cross-sectional view of the cross section along the dashed line in Figure 3, as seen in the direction of arrow VV. Figure 5(b) is an example of an enlarged view of the area within the frame indicated by the dashed line in Figure 5(a). Figure 5(c) is a cross-sectional view of the end of the conductor portion according to the second embodiment, and is another example of an enlarged view of the area within the frame indicated by the dashed line in Figure 5(a). Figure 6(a) is a schematic plan view of the end of the conductor portion according to the second embodiment, as seen from the connection surface side of the conductor portion. Figure 6(b) is a cross-sectional view of the cross-section along the dashed line in Figure 6(a) as seen in the direction of arrow VIb-VIb. Figure 6(c) is a cross-sectional view of the cross-section along the dashed line in Figure 6(a) as seen in the direction of arrow VIc-VIc. This is another example of a schematic plan view of the end of a conductor according to the second embodiment, as seen from the connection surface side of the conductor. Figures 8(a) and 8(b) are cross-sectional views showing an example of the uneven structure of the end of a conductor according to the third embodiment. This is a schematic plan view of the end of a conductor according to the first modified example, as seen from the connection surface side of the conductor. This is a schematic plan view of the end of a conductor according to the second modified example, as seen from the connection surface side of the conductor.

[0012] The various components of the inductor and coil of the present invention do not need to be independent entities; it is permissible for multiple components to be formed as a single member, for one component to be formed from multiple members, for one component to be part of another component, for a part of one component to overlap with a part of another component, and so on.

[0013] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, corresponding components are denoted by the same reference numeral, and redundant explanations will be omitted as appropriate. In this embodiment, the directions of front, back, left, right, up, and down are defined and described as shown in the figures. However, this is defined for convenience in order to easily explain the relative relationships of the components and does not limit the direction during manufacturing or use of the product implementing the present invention. Furthermore, the term "plane" in this invention refers to a shape that is physically formed with a plane as the target, and naturally, it is not required to be a geometrically perfect plane.

[0014] <First Embodiment> (Inductor) Figure 1 is a schematic perspective view showing an example of an inductor 1 according to the first embodiment of the present invention.

[0015] First, an overview of the inductor 1 of this embodiment will be described. The inductor 1 has a conductor portion 10. The conductor portion 10 (coil 10a, which will be described later in this embodiment) is a member including an end portion 20 and is the part that generates inductance. The end portion 20 of the conductor portion 10 is a flat plate having two opposing main surfaces 22. The end portion 20 also has a hole 24 that penetrates in the thickness direction. On one of the main surfaces 22 (connecting surface 22a) of the end portion 20 of the conductor portion 10, an uneven region 30 having an uneven structure 30a is formed around the hole 24. As described above, an uneven region 30 having an uneven structure 30a is formed on the main surface 22 of the end portion 20 of the conductor portion 10. As a result, when the screw 40 is tightened and the surface of the end portion 20 of the conductor portion 10 (connecting surface 22a) is pressed against the surface of the object to be connected (conductive member 50, which will be described later), the protrusions (ridges 32) formed in the uneven region 30 bite into the surface of the object to be connected and make contact with the object to be connected. As a result, sufficient contact can be ensured between the uneven region 30 and the surface to be connected, and the surface of the end portion 20 of the conductor portion 10 can make good contact with the surface to be connected.

[0016] Next, the inductor 1 of this embodiment will be described in detail. The inductor 1 is a component (electronic component) that constitutes an electrical circuit. In particular, the inductor 1 is a component that generates voltage in response to changes in current within an electrical circuit. The inductor 1 is a component that generates inductance by including a conductive portion 10, which is the part that generates inductance, as will be described later. In this embodiment, the inductor 1 is electrically connected to other components by a member that is electrically connected to the conductive portion 10 (a conductive member 50, which will be described later, or another member connected to the conductive member 50), thereby constituting an electrical circuit.

[0017] The inductor 1 may be connected to a conductive member 50 (busbar 50a), described later, to constitute an electrical device 100 together with other components. Examples of electrical devices 100 that include the inductor 1 include a battery device, a generator, an electric motor, or a power control device. Alternatively, the inductor 1 may be provided as an inductor element without including the conductive member 50, described later. Or, the inductor 1 may be provided as an inductor element including a conductive member 50 connected to the end 20 of the conductor portion 10.

[0018] As described above, the conductor portion 10 is the part of the inductor 1 that generates inductance (inductor generating portion). In other words, the conductor portion 10 is the part of the inductor 1 that generates a magnetic field around it when current flows through it. More specifically, the conductor portion 10 is the part that, when current flows through it, can generate a stronger magnetic field than other members connected to the conductor portion 10 (for example, conductive members such as the conductive member 50 described later). More specifically, the conductor portion 10 is a member that includes a long conductive material having a helical shape, as described later, or a long conductive material surrounded by a magnetic core. In this embodiment, the conductor portion 10 is a coil 10a formed by spirally shaping a long conductive material. Forming a long conductive material spirally means that the long conductive material is wound at least once around a hypothetical helical axis. In this embodiment, the coil 10a is made by winding a long conductive material multiple times around a helical axis (an axis extending in the vertical direction). In this embodiment, the long conductive material is a coil wire (flat wire) with a rectangular cross-section. That is, the cross-sectional shape of the coil wire in this embodiment is rectangular, and it is a flattened shape with a thickness dimension that is sufficiently smaller than the width dimension. The cross-sectional shape of the conductive material may be circular (including perfect circles and ellipses). For example, the conductive material may be a round wire. Also, the cross-sectional shape of the conductive material may be a flattened shape with a thickness dimension that is sufficiently smaller than the width dimension, or it may be a shape where the thickness dimension and width dimension are approximately the same. Furthermore, the inductor 1 in this embodiment may include a core made of a magnetic material. Specifically, the core may be located on the inner diameter side, the outer diameter side, or both sides of the coil 10a. Alternatively, the inductor 1 may not include a core.

[0019] The conductor portion 10 is not limited to a coil 10a as in this embodiment; the shape of the conductor portion 10 is not limited as long as it is a part that generates inductance. For example, as described above, the conductor portion 10 may be a long conductive material surrounded by a magnetic core. Preferably, the conductor portion 10 is a conductive material embedded in a magnetic core. For example, the conductor portion 10 may be a linear conductive material. Specifically, the conductor portion 10 may be a long plate-shaped member.

[0020] Furthermore, the conductor portion 10 includes an end portion 20. Specifically, the conductor portion 10 is formed from a long member, and the portion including one end in the longitudinal direction of the long member is the end portion 20 of the conductor portion 10. For example, in this embodiment, the coil 10a is formed from a long coil wire (flat wire), and the portion including one end of the coil wire is the end portion 20 (coil end portion 20a). The end portion 20 of the conductor portion 10 is an arbitrary length region including one end of the conductor portion 10. Only the portion near one end of the conductor portion 10 may be considered the end portion 20 of the conductor portion 10, or the entire coil wire (outline portion) drawn out from the winding portion around which the coil wire is wound in the conductor portion 10, which is the coil 10a, may be considered the end portion 20 of the conductor portion 10. In other words, the end portion 20 of the conductor portion 10 is not formed by joining a terminal component formed as a separate member from the coil 10a to the coil 10a, but is constructed as a continuous unit from the same member as the coil 10a. In the following description, the end portion 20 of the conductor portion 10 in this embodiment will be described as a coil end portion 20a.

[0021] In this embodiment, the coil 10a has a spirally wound portion housed within the case 60, and the coil end 20a is exposed from the case 60. More specifically, a portion of the coil wire (outer portion) in this embodiment is pulled out from the winding portion toward the front, and this outer portion is bent upward. The coil end 20a, which is a portion extending in the vertical direction, is fitted into an opening provided in the case 60 and is exposed from the case 60.

[0022] As shown in Figures 2(a) and 2(b), the shape of the coil end 20a is flat. In other words, the dimension of the end 20 in the thickness direction (front-to-back direction) is sufficiently smaller than the dimension of the end 20 in the extension direction (up-down direction and left-to-right direction). The surface of the flat coil end 20a includes two opposing main surfaces 22 (connecting surface 22a and back surface 22d). The connecting surface 22a is the surface of the two main surfaces 22 that contacts the conductive member 50, which will be described later, and is electrically connected to it. The back surface 22d is the main surface of the two main surfaces that faces the connecting surface 22a.

[0023] As shown in Figure 3, the shape of the end portion 20 (coil end portion 20a) of the conductor portion 10 in this embodiment, when viewed from the direction of penetration through the hole 24, is substantially rectangular. That is, the shape of the coil end portion 20a is recognizable as consisting of four corners and four substantially straight sides connecting two adjacent corners. Here, the sides connecting the corners may be perfectly straight or slightly curved. Alternatively, the shape of the end portion 20 of the conductor portion 10 when viewed from the direction of penetration through the hole 24 is not limited to a rectangle, but may be circular, polygonal, or other shapes.

[0024] As shown in Figure 3, the conductor portion 10 of the end 20 includes a first side surface 23 and a second side surface 25 as side surfaces. The side surfaces of the conductor portion 10 of the end 20 are surfaces that connect the peripheral edges of the two main surfaces 22, 22. The first side surface 23 is a part of the surface (side surface) of the end 20 that faces in a direction perpendicular to the direction described later (one of the perpendicular directions). In this embodiment, the first side surface 23 is the surface facing upward in the figure on the rectangular coil end 20a. The second side surface 25 is a part of the surface (side surface) of the end 20 that faces in the direction of end extension (one of the end extension directions), which will be described later. In this embodiment, the second side surface 25 is the surface facing left or right in the figure on the rectangular coil end 20a. When a part of a side surface faces a predetermined direction, it means that the direction of the normal of that part of surface is aligned with that predetermined direction. When a side surface is curved, the normal of that side surface refers to the normal of the approximately central part of that side surface. Here, the statement that the direction of the normal of the part of the surface is aligned with the predetermined direction does not mean that the direction of the normal is perfectly parallel to the predetermined direction. The direction of the normal may extend at a slight angle to the predetermined direction. The end extension direction is the direction connecting the base end and the tip (one end of the coil wire) of the coil end 20a. The end extension direction is the vertical direction in Figure 3. The orthogonal direction is the direction perpendicular to the end extension direction. More specifically, the orthogonal direction is the direction perpendicular to both the end extension direction and the thickness direction. The orthogonal direction is the left-right direction in Figure 3.

[0025] Alternatively, even if the shape of the coil end 20a as viewed from the through-direction (thickness direction) of the hole 24 is polygonal, circular, or irregular, the side surface of the coil end 20a may include the first side surface 23 and the second side surface 25.

[0026] In this embodiment, the conductor portion 10 includes a portion (adjacent portion 20b) on the base end side of the portion where the uneven structure 30a is formed, where the uneven structure 30a is not formed. In this embodiment, the dimensions of the portion (coil end portion 20a) where the uneven structure 30a is formed in the orthogonal direction, as described later, are larger than the dimensions of the adjacent portion 20b in the same orthogonal direction. This makes it possible to increase the area of ​​the uneven region 30 that contacts the busbar 50a.

[0027] As shown in Figure 2(b), a hole 24 is formed in the end portion 20 of the conductor portion 10, penetrating through the end portion 20 in the thickness direction (front-to-back direction). The hole 24 is open in each of the two main surfaces 22. As shown in Figure 3, in this embodiment, the shape of the hole 24 when viewed in the thickness direction is circular, but it may be polygonal or other shapes. In this embodiment, the hole 24 is an elongated hole. Specifically, the dimensions of the hole 24 in the end extension direction are larger than the dimensions of the hole 24 in the orthogonal direction. The hole 24 is defined by an inner wall surface that extends in a direction intersecting the main surface 22 of the coil end portion 20a. More specifically, the inner wall surface defining the hole 24 extends approximately orthogonally to the main surface 22 of the coil end portion 20a.

[0028] As shown in Figure 2(b), the inductor 1 or electrical device 100 (see Figure 1) has a conductive member 50 (busbar 50a in this embodiment) that is electrically connected to the coil end 20a. The conductive member 50 in this embodiment is a busbar 50a having a surface (flat surface) that contacts the coil end 20a. The conductive member 50 is not limited to a busbar 50a, but is a conductive member that can be electrically connected to the coil end 20a, and the shape of the conductive member 50 is not limited. The busbar 50a in this embodiment is arranged inside the case 60. The busbar 50a in this embodiment also has a hole into which a shaft member (screw 40), which will be described later, is inserted. The hole in this embodiment is a female threaded portion into which the screw 40, which will be described later, is screwed. Alternatively, the hole may be a through hole in which a screw groove for screwing the screw 40 is not formed on the inner wall surface, in which case the coil end 20a and the busbar 50a may be fastened with the screw 40 using a nut, as will be described later.

[0029] The coil end 20a and the busbar 50a are fixed by a shaft member. Specifically, the shaft member is inserted into the hole 24 in the coil end 20a and the hole in the busbar 50a to fix the coil end 20a and the busbar 50a in the desired positional relationship. Furthermore, the coil end 20a and the busbar 50a are maintained in contact with each other (pressure-contact or abutting) in the thickness direction of the coil end 20a. As a result, the coil end 20a is electrically connected to the busbar 50a. In this embodiment, the coil end 20a is connected to the busbar 50a by a screw 40. In other words, the state in which the coil end 20a is press-contact or abutting with the busbar 50a is maintained by tightening the screw 40. Alternatively, the state in which the coil end 20a and the busbar 50a are press-contact or abutting with each other may be maintained by a screw and a nut that screws into the screw.

[0030] As shown in Figure 3, a recessed area 30 is formed on the connection surface 22a around the hole 24. The recessed area 30 is at least a portion (partial or all) of the connection surface 22a and is a surface area on which the recessed structure 30a is formed. In other words, the recessed area 30 is a region with greater irregularities than other regions (for example, regions adjacent to the recessed area 30, or other surface regions such as the back surface 22d). The recessed area 30 is a planar region that extends along the extending direction of the connection surface 22a. When we say that the recessed area 30 is formed around the hole 24, we mean that the recessed area 30 is formed on a portion of the connection surface 22a that is close to the hole 24. More specifically, it is preferable that the shortest distance between the hole 24 and the recessed area 30 along the connection surface 22a (the distance between the inner wall surface defining the hole 24 and the inner edge of the recessed area 30 when viewed from the direction of penetration of the hole) is smaller than the overhang dimension of the screw head 40. Here, the head overhang dimension is the length (radial dimension) from the circumferential surface of the shaft portion of the screw 40 to the outer edge of the head. Alternatively, it is preferable that this distance is smaller than the radius of the hole 24. This distance may also be zero. By arranging the uneven region 30 around the hole 24 in this way, when the screw 40 is tightened, the uneven structure 30a, described later, can be pressed against the busbar 50a with sufficient force.

[0031] In this embodiment, the uneven region 30 is formed to completely surround the perimeter of the hole 24. In other words, the uneven region 30 is formed outward in all directions in the radial direction of the hole 24. Here, the radial direction of the hole 24 is the direction from the center of the hole 24 toward the outer edge of the hole 24 (the inner wall surface that defines the hole 24). In this embodiment, where the shape of the hole 24 when viewed in the thickness direction is circular, the radial direction of the hole 24 is the radial direction of the hole 24. Alternatively, the uneven region 30 may not be formed to completely surround the perimeter of the hole 24. In other words, the uneven region 30 may be formed only outward in a part of the radial direction of the hole 24, and not formed outward in other parts of that radial direction.

[0032] The uneven structure 30a is a structure having recesses or protrusions. As described above, the entire uneven region 30 has a rougher surface than the areas outside the uneven region 30 due to the presence of the uneven structure 30a. Here, a recess in the uneven structure 30a is a structure that is recessed in the thickness direction toward the inside of the coil end 20a compared to other parts of the uneven region 30. Here, a protrusion in the uneven structure 30a is a structure that protrudes outward in the thickness direction toward the outside of the coil end 20a compared to other parts of the uneven region 30. Here, the direction in which the protrusion protrudes is called the protrusion direction, and the direction in which the recess is recessed is called the recess direction. The protrusion direction is approximately opposite to the recess direction.

[0033] As shown in Figure 3, in this embodiment, the uneven structure 30a is formed by two or more convex ridges 32 and bottomed grooves 34 that are aligned with each other. Specifically, at least one convex ridge 32 and at least one groove 34 are formed in the uneven region 30, and the one convex ridge 32 and the one groove 34 extend along each other. The top of the convex ridge 32 extends in a predetermined direction and is a portion that protrudes in the protruding direction more than other parts (for example, the bottom of the groove 34). The bottom of the groove 34 extends in a predetermined direction and is a portion that is recessed in the recessing direction more than other parts (for example, the top of the convex ridge 32). In this embodiment, as shown in Figure 4(a), two or more convex ridges 32 and two or more grooves 34 are formed in the uneven region 30. The convex ridges 32 and grooves 34 are arranged alternately side by side. In other words, a groove 34 is formed at the boundary between two adjacent convex ridges 32. To put it another way, a ridge 32 is formed at the boundary between two adjacent grooves 34. More specifically, one groove 34 is sandwiched between two ridges 32, and is formed by recessing in the direction of the depression from the top of each of the two ridges 32 (the top surface 32d, which will be described later in this embodiment). The wall surface (slope) defining one groove 34 coincides with the respective slope surfaces of the two ridges 32. The protruding end 32a of the ridge 32, which will be described later, forms the opening of the groove 34. Similarly, one ridge 32 is sandwiched between two adjacent grooves 34, and is formed by protruding in the direction of the projection from the bottom of each of the two depressions. Since the ridge 32 protrudes from the surface (virtual surface) that includes the bottom of the groove 34, the bottom of the groove 34 can be said to be the base end of the ridge 32.

[0034] In this embodiment, a portion of a single protrusion 32 may be called the protruding end 32a, and another portion of the same protrusion 32 may be called the base end. The protruding end 32a is the portion of the protrusion 32 that contacts the conductive member 50 (bus bar 50a). In this embodiment, the protrusion 32 contacts the bus bar 50a at its protruding end (top). In other words, the protruding end 32a is a portion of the protrusion 32 that includes its protruding end (top). In this embodiment, the protruding end 32a is a portion of the protrusion 32 that includes the top surface 32d, which will be described later. The base end 32b is a portion of the protrusion 32 that is closer to the base end in the protruding direction of the protrusion 32 than the protruding end 32a. More specifically, the base end 32b is a portion of the protrusion 32 that includes the base end of the protrusion 32. In this embodiment, the base end of the protrusion 32 is a portion adjacent to the bottom of the groove 34.

[0035] The uneven structure 30a is not limited to being composed of two or more convex ridges 32 and grooves 34 that are aligned with each other. For example, instead of this embodiment, the uneven structure 30a may be formed by a plurality of convex ridges that intersect with each other. That is, convex ridges may be formed in a mesh-like pattern in the uneven region 30. Another example is that the uneven structure 30a may be formed by grooves that intersect with each other. Another example of an uneven structure 30a is a structure in which a plurality of protrusions (for example, protrusions having the shape of a cone or pyramid) are scattered in the uneven region 30.

[0036] In this embodiment, as shown in Figure 4(b), the top (protruding end) of the ridge 32 is a planar top surface 32d. The top of the ridge 32 is the part that protrudes the most within the width of the ridge 32. In other words, the top of the ridge 32 being planar means that the part that protrudes the most within the width of the ridge 32 has a region that extends in the width direction of the ridge 32. That is, the top surface 32d of the ridge 32 is a surface that has dimensions in the width direction of the ridge 32 and extends in the direction of extension of the ridge 32. In this embodiment, the top surface 32d is a flat surface from one end to the other of the ridge 32 (a surface that extends parallel to the connecting surface 22a), but is not limited to this. For example, part or all of the top surface 32d may be an inclined surface (a surface that extends at a slight inclination with respect to the connecting surface 22a). Furthermore, the top surface 32d in this embodiment is a smooth surface (a surface without steps) that extends continuously from one end to the other of the ridge 32, but is not limited to this. The top surface 32d may have steps (corners, or curved portions with a smaller radius of curvature than other parts of the top surface 32d) in the middle of the extension direction of the ridge 32. For example, in the second embodiment described later, the top surface 32d includes a portion between the flat top surface 32d1 and the inclined top surface 32d2 that has a smaller radius of curvature than the flat top surface.

[0037] As shown in Figure 4(b), in this embodiment, the dimension of the top surface 32d of the protrusion 32 in the width direction (width dimension L1) is greater than the dimension of the protrusion 32 in the projection direction (projection dimension L2). The width direction of the protrusion 32 is the direction perpendicular to the extension direction and projection direction (thickness direction of the coil end 20a) of the protrusion 32, respectively. In other words, the width direction of the protrusion 32 is the direction in which multiple protrusions 32 are arranged side by side. In this embodiment, the projection dimension of the protrusion 32 is the height from the bottom of the groove 34 to the top of the protrusion 32 in the projection direction. Also, in this embodiment, the projection dimension of the protrusion 32 coincides with the depth dimension of the groove 34. The depth dimension of the groove 34 is the depth from the top of the protrusion 32 (top surface 32d) to the bottom of the groove 34 in the recess direction. As the width dimension of the top surface 32d is large, it is possible to secure a large area of ​​contact with the surface of the busbar 50a in the uneven region 30. On the other hand, because the width dimension of the top surface 32d is large and the protrusion dimension of the ridge 32 is small, the surface of the busbar 50a is less likely to be accidentally damaged by the ridge 32.

[0038] As shown in Figure 4(b), in this embodiment, the width dimension L1 of the top surface 32d of the protrusion 32 is larger than the width dimension (width dimension L5) of the bottom of the groove 34 in the width direction. By reducing the distance between the base ends of the protrusions 32 (width dimension of the bottom of the groove 34) while increasing the width dimension of the top surface 32d of the protrusion 32, it is possible to secure a sufficient area of ​​the portion that can contact the surface of the busbar 50a in the uneven region 30.

[0039] As shown in Figure 4(b), in this embodiment, the pitch L6 of the two adjacent grooves 34 is greater than the dimension of the protruding ridge 32 in the protruding direction (protrusion dimension L2). Here, in this embodiment, the pitch of the two adjacent grooves 34 coincides with the pitch of the two adjacent protruding ridges 32. The pitch of the two adjacent grooves 34 is the distance from the bottom of one groove 34 to the bottom of the other groove 34 located next to it. In this way, because the pitch of the two grooves 34 is large and the protruding dimension of the protruding ridge 32 is small, as described above, the surface of the busbar 50a is less likely to be unexpectedly damaged by the protruding ridge 32, and a sufficient contact area with the busbar 50a can be ensured.

[0040] Furthermore, as shown in Figure 4(b), in this embodiment, the cross-sectional shape of the protrusion 32 (the cross-section along the width direction of the protrusion 32) is trapezoidal. That is, the protrusion 32 is defined by a top surface 32d and a pair of inclined surfaces. These inclined surfaces are inclined with respect to the protruding direction of the protrusion 32 (the thickness direction of the coil end 20a) and the extending direction of the top surface 32d. In this embodiment, the smaller of the angles formed by the pair of inclined surfaces that define one protrusion 32 is 90 degrees or more. Also, in this embodiment, the cross-sectional shape of the recess 34 (the cross-section along the width direction of the recess 34) is trapezoidal. That is, the recess 34 is defined by a bottom and a pair of inclined surfaces. These inclined surfaces are inclined with respect to the recess direction of the recess 34 and the extending direction of the bottom. In this embodiment, the smaller of the angles formed by the pair of inclined surfaces that define one recess 34 is 90 degrees or more. Thus, by having the smaller of the angles formed by the pair of inclined surfaces defining one protrusion 32 be obtuse, or by having the smaller of the angles formed by the pair of inclined surfaces defining one recess 34 be obtuse, the surface of the busbar 50a is less likely to be unexpectedly damaged by the protrusion 32, and a sufficient contact area with the busbar 50a can be ensured.

[0041] As shown in Figure 3, in this embodiment, the convex ridges 32 and grooves 34 extend along the orthogonal direction (left-right direction in the figure). The extension of the convex ridges 32 and grooves 34 along the orthogonal direction includes not only the case where the extension direction of the convex ridges 32 and grooves 34 is orthogonal, but also the case where the extension direction of the convex ridges 32 and grooves 34 is slightly inclined with respect to the orthogonal direction. Specifically, the extension direction of the convex ridges 32 and grooves 34 is a direction that includes an orthogonal component that is larger than the end extension direction component. Preferably, the extension direction of the convex ridges 32 and grooves 34 is orthogonal. Since the coil wire is long in the end extension direction, when processing the coil wire (especially the coil end 20a), the coil end 20a may be unexpectedly deformed so that the end extension direction of the coil end 20a is curved. That is, the coil end 20a may be deformed so that the coil end 20a is curved in a cross section along the end extension direction (cross section in Figure 4(a)). In this case, because the convex ridge 32 and the concave groove 34 are aligned in orthogonal directions, it becomes easier to return the coil end 20a, which has deformed so that its end extension direction is curved, back to a flat state. In particular, when the convex ridge 32 and the concave groove 34 are aligned in orthogonal directions, when the screw 40 is tightened, stress is applied to the main surface 22 (especially the back surface 22d) of the coil end 20a with the head of the screw 40, and the deformed coil end 20a can be returned to a nearly flat state.

[0042] Alternatively, the convex ridge 32 and concave groove 34 may extend along the terminal extension direction, or they may extend in a direction oblique to both the terminal extension direction and the perpendicular direction (the oblique direction in Figure 3).

[0043] As shown in FIG. 3, in the present embodiment, when viewed from the penetration direction of the hole 24, the first side surface 23 is a curved surface that bulges outward from the inside to the outside of the coil end portion 20a in the orthogonal direction (the left - right direction in the figure). In other words, when viewed from the penetration direction of the hole 24, the outer edge of the first side surface 23 is a curved shape that curves so as to bulge outward from the inside to the outside of the coil end portion 20a in the orthogonal direction. For example, the outer shape of the first side surface 23 facing left in the figure (the outer shape on the left side of the coil end portion 20a) is a curve that curves so as to bulge leftward. Here, the direction from the inside to the outside of the coil end portion 20a in the orthogonal direction may be referred to as the orthogonal outward direction. In the present embodiment, as will be described later, since the first side surface 23 is a convex surface that bulges in the orthogonal outward direction, the outer edge of the first side surface 23 when viewed from the penetration direction of the hole 24 is a curve that curves so as to bulge in the orthogonal outward direction. As described above, since the first side surface 23 is a curved surface, the coil end portion 20a and the bus bar 50a can come into good contact. Specifically, since the first side surface 23 is a curved surface, when the screw 40 is tightened to apply stress to the coil end portion 20a, the coil end portion 20a expands and deforms easily so as to bulge in the orthogonal outward direction. Thus, when the screw 40 is tightened, the periphery of the hole 24 can be deformed appropriately in the orthogonal outward direction, and the coil end portion 20a can change into a shape that fits the shape sandwiched between the screw 40 and the bus bar 50a. As a result, the coil end portion 20a can come into good contact with the bus bar 50a.

[0044] As shown in FIG. 3, in the present embodiment, when viewed from the penetration direction of the hole 24, a part of the first side surface 23 that bulges most in the orthogonal outward direction overlaps the hole 24 in the orthogonal direction. Thus, since a part of the side of the hole 24 in the first side surface 23 bulges most in the orthogonal outward direction, when the screw 40 is tightened, the uneven structure 30a around the hole 24 is deformed efficiently, and the coil end portion 20a can come into good contact with the bus bar 50a.

[0045] As shown in Figure 3, in this embodiment, when viewed from the direction of penetration of the hole 24, the amount of bulge L3 of the first side surface 23, which is a curved surface, is greater than the amount of bulge L4 of the second side surface 25 in the direction from the inside to the outside of the coil end 20a in the end extension direction (upward in the figure). Hereinafter, the direction from the inside to the outside of the coil end 20a in the end extension direction may be referred to as the end extension outward direction. Here, the amount of bulge of the second side surface 25 also includes zero. That is, the second side surface 25 may not bulge in the end extension outward direction and may be a flat surface. In other words, the first side surface 23 bulges outward orthogonally while the second side surface 25 is a flat surface, or when viewed from the direction of penetration of the hole 24, the second side surface 25 bulges outward in the end extension direction, and the amount of bulge L3 of the first side surface 23, which is a curved surface, is greater than the amount of bulge L4 of the second side surface 25. As described above, while the first side surface 23 bulges outward perpendicularly, the shape of the coil end 20a on the second side surface 25 is controlled so that it does not bulge outward at the end. As a result, even when the screw 40 is tightened and stress is applied to the coil end 20a, the coil end 20a deforms outward perpendicularly, but it is less likely to deform outward at the end. By suppressing deformation that causes the coil end 20a to spread in the end-extending direction in this way, the uneven structure 30a is prevented from collapsing (the uneven region 30 becomes flattened).

[0046] In this embodiment, as shown in Figure 5(a), when viewed in the end-extending direction, the first side surface 23 is a curved surface that bulges outwards from the inside to the outside of the coil end 20a in the orthogonal direction (left-right direction in the figure). In other words, when viewed in the end-extending direction, the outer edge of the first side surface 23 is a curve that bulges outwards orthogonally. That is, in this embodiment, the first side surface 23 is a convex surface (approximately spherical) that bulges outwards from the inside to the outside of the coil end 20a in the orthogonal direction (left-right direction in the figure). That is, the first side surface 23 is a convex surface that bulges outwards most orthogonally at its center. Because the first side surface 23 is a convex surface in this way, as described above, when the screw 40 is tightened, the coil end 20a deforms well and the coil end 20a and the busbar 50a can make good contact. Also, because the first side surface 23 is a convex surface, the top surfaces 32d of both ends (ends in the orthogonal direction) of the protrusion 32 incline inwards in the thickness direction of the coil end 20a as it extends outwards orthogonally. This prevents the ends of the protrusions 32 from becoming sharp corners and protruding outwards from the coil end 20a. As a result, it prevents foreign matter from being generated from the inductor 1, such as when a part of the protrusions 32 is chipped off.

[0047] In this embodiment, as described above, the first side surface 23 bulges outward orthogonally when viewed in the direction of penetration of the hole 24 and in the direction of end extension, but it is not limited to this. Instead of this embodiment, the first side surface 23 may bulge outward orthogonally when viewed in the direction of penetration of the hole 24, but may not bulge outward orthogonally when viewed in the direction of end extension. That is, when viewed in the direction of end extension, the outer shape (outer edge) of the first side surface 23 may be a straight line. Specifically, the first side surface 23 may be a surface with a shape that can be approximated as a cylindrical surface formed by compressing a flat surface in one direction. Alternatively, instead of this embodiment, the first side surface 23 may not bulge outward orthogonally and may be a flat surface.

[0048] The concavo-convex structure 30a in this embodiment is formed using a mold having a shape obtained by inverting the concavo-convex structure 30a. Specifically, it is formed by pressing the main surface (connection surface 22a) of the coil end portion 20a with the mold. Alternatively, the concavo-convex structure 30a is formed by cutting the main surface (connection surface 22a) of the coil end portion 20a. Alternatively, the concavo-convex structure 30a is formed by depositing a conductive material on the main surface (connection surface 22a) of the coil end portion 20a. Also, a hole 24 is formed in the coil end portion 20a by punching or the like. The formation of the hole 24 may be performed before forming the concavo-convex structure 30a, after forming the concavo-convex structure 30a, or simultaneously with the formation of the concavo-convex structure 30a. For example, by using a mold capable of simultaneously forming the hole 24 and the concavo-convex structure 30a, the formation of the hole 24 may be performed simultaneously with the formation of the concavo-convex structure 30a.

[0049] Next, in the inductor 1 of this embodiment, it is explained that the surface of the end portion 20 of the conductor portion 10 is surely in good contact with the surface of the connection target. Specifically, it is explained that the direct current resistance (DCR, Direct Current Resistance) of the inductor 1 is reduced by forming the concavo-convex structure 30a in the coil end portion 20a as compared with the case where the concavo-convex structure 30a is not formed in the coil end portion 20a. Table 1 shows the results of comparing the direct current resistances in the case where the concavo-convex structure 30a is formed in the coil end portion 20a and the case where the concavo-convex structure 30a is not formed. In all six samples, the value of the direct current resistance obtained when the concavo-convex structure 30a was formed was smaller than the value of the direct current resistance obtained when the concavo-convex structure 30a was not formed. Also, based on the value of the direct current resistance when the concavo-convex structure 30a was not formed, the reduction rate of the direct current resistance when the concavo-convex structure 30a was formed was about 21.8% to 47.0%. From the above, it was confirmed that the value of the direct current resistance is reduced by forming the concavo-convex structure 30a in the coil end portion 20a. From this, it was suggested that by forming the concavo-convex structure 30a in the coil end portion 20a, the surface of the coil end portion 20a is in good contact with the surface of the bus bar 50a which is the connection target.

[0050] (Coil) The coil 10a, which is the conductor portion in this embodiment, may be provided as a single unit. As described above, the coil 10a includes an end portion 20 (coil end portion 20a). The end portion 20 is a flat plate having two opposing main surfaces 22 and has a hole 24 that penetrates in the thickness direction. On one of the main surfaces 22 (connecting surface 22a) of the end portion 20, an uneven region 30 having an uneven structure 30a is formed around the hole 24. The coil can be used in all types of components having a coil (coil components). For example, the coil can be used in coil components including inductors, transformers, or antenna components.

[0051] <Second Embodiment> First, an overview of the inductor of this embodiment will be described.

[0052] In the inductor 1 of this embodiment, as described above, an uneven region 30 having an uneven structure 30a is formed on the connection surface 22a around the hole 24.

[0053] Next, the inductor 1 of this embodiment will be described in detail. The inductor 1 of this embodiment differs from the first embodiment in that, as shown in Figure 5(c), the protruding height of one of the protrusions 32 decreases as it approaches the hole 24 in the orthogonal direction. By decreasing the protruding height of the protrusion 32 as it approaches the hole 24, deformation of the coil end 20a so as to spread inward into the hole 24 is suppressed during tightening of the screw 40. This is because the part of the protrusion 32 that is close to the hole 24 receives less stress from the busbar 50a than the part of the protrusion 32 that is not close to the hole 24. By suppressing deformation of the coil end 20a so as to spread inward into the hole 24, it is less likely that the hole 24 will become too small, and the screw 40 can be tightened all the way in.

[0054] As shown in Figure 5(c), in this embodiment, the top surface 32d of the protrusion 32 is gradually inclined toward the hole 24. More specifically, the top surface 32d of the protrusion 32 is inclined toward the back surface 22d in the direction of penetration of the hole 24 toward the hole 24. Alternatively, the top surface 32d of the protrusion 32 may be formed in a stepped shape. That is, the protrusion height of the protrusion 32 may decrease in stages toward the hole 24.

[0055] Furthermore, the height of one protrusion 32 may decrease as it approaches the hole 24 in the direction of extension of the end (width direction of the protrusion 32). In addition, of two adjacent protrusions 32, the protruding height of the protrusion 32 that is closer to the hole 24 may be smaller than the protruding height of the other protrusion 32. This makes it possible to suppress the occurrence of the hole 24 becoming too small when the screw 40 is tightened, over approximately the entire circumference of the hole 24.

[0056] Figures 6(a) to 6(c) are plan views or cross-sectional views showing an example of the coil end in the inductor 1 according to this embodiment. In this embodiment, as described in the first embodiment, the top of the protrusion 32 is a planar top surface 32d. In this embodiment, the uneven region 30 includes at least a part of the peripheral region 36 surrounding the hole 24. The peripheral region 36 is an inclined surface that slopes toward the other main surface 22 (back surface 22d) in the direction of penetration of the hole 24 as it approaches the hole 24, and includes the top surface 32d of the protrusion 32. With the above configuration, it is possible to suppress the occurrence of the hole 24 becoming too small when tightening the screw 40 as described above. Also, because the top surface 32d of the protrusion 32 slopes downward as it approaches the hole 24, the end of the protrusion 32 on the hole 24 side is less likely to become a sharp corner that protrudes toward the outside of the coil end 20a. Therefore, chipping of the protrusion 32 is suppressed, and foreign matter is less likely to be generated from the inductor 1.

[0057] As shown in Figure 6(a), the peripheral region 36 is the inclined region around the hole 24, and is located surrounding the hole 24. In Figure 6(a), the peripheral region 36 is the region within the frame of the dashed line A. More specifically, the peripheral region 36 is the region sandwiched between the dashed line A and the inner wall surface defining the hole 24 (region A in Figures 6(b) and 6(c)). The dashed line A is also the boundary line between the flat top surface 32d1 and the inclined top surface 32d2, which will be described later. More specifically, in this embodiment, the boundary shown by the dashed line A is a virtual boundary connecting the boundaries of the flat top surface 32d1 and the inclined top surface 32d2, and is the outer edge of the peripheral region 36. As shown in Figures 6(b) and 6(c), the peripheral region 36 is an inclined surface that slopes toward the back surface 22d side in the direction of penetration of the hole 24 as it approaches the hole 24. In other words, the peripheral region 36 has a shape that narrows downwards (funnel-shaped) and slopes toward the hole 24. The inclined surface in the peripheral region 36 is a surface that can be recognized as being inclined toward the hole. Specifically, in this embodiment, the peripheral region 36, which is the area within the dashed line A in Figure 6(a), includes the end of the groove 34 and has irregularities on its surface. However, the peripheral region 36 can be recognized as an inclined surface because the surface of the area within the dashed line B in Figure 6(a) and the inclined top surface 32d2 are inclined.

[0058] Here, it is preferable that the smaller of the angles that the inclined peripheral region 36 (especially the inclined top surface 32d2) makes with the direction of extension (orthogonal direction) of the convex ridge 32 or concave groove 34 is 45 degrees or less. In other words, it is preferable that the inclined peripheral region 36 is a surface that slopes gently with respect to the main surface 22.

[0059] As shown in Figure 6(a), the outer edge (dotted line A) of the inclined peripheral region 36 is located radially inward from the outer edge (outer edge of the uneven region 30) of the coil end 20a. In other words, a flat surface (flat top surface 32d1) is located outside the inclined peripheral region 36 in the radial direction.

[0060] In this embodiment, as shown in Figures 6(b) and 6(c), the peripheral region 36 is an inclined surface that bulges outwards in the direction of projection. This makes it easier for the inclined surface to come into contact with the busbar 50a. Alternatively, the peripheral region 36 may be an inclined surface with a straight cross-section.

[0061] In this embodiment, the uneven region 30 is the region radially outward from the dashed-dotted line B shown in Figure 6(a). The dashed-dotted line B indicates the portion at the same height as the bottom of the groove 34 in the thickness direction. The region radially inward from the dashed-dotted line B shown in Figure 6(a) (region B in Figures 6(b) and 6(c)) is the region where the uneven structure 30a is not formed. More specifically, the region radially inward from the dashed-dotted line B shown in Figure 6(a) is located on the back surface 22d side of the bottom of the groove 34 in the thickness direction. As shown in Figure 6(a), in this embodiment, the uneven region 30 includes a part of the peripheral region 36. Specifically, the uneven region 30 includes a part radially outward from the peripheral region 36. More specifically, the region between the dashed-dotted line A and the dashed-dotted line B in Figure 6(a) is a part of the uneven region 30 and a part of the peripheral region 36. Alternatively, the entire peripheral region 36 may be included in the uneven region 30.

[0062] As shown in Figure 6(a), the peripheral region 36, which is an inclined surface, includes a part of the top surface 32d of the protrusion 32. In other words, as shown in Figures 6(b) and 6(c), the top surface 32d of the protrusion 32 is inclined to approach the back surface 22d side in the direction of penetration of the hole 24 as it approaches the hole 24. In this embodiment, as shown in Figures 6(a) to 6(c), the top surface 32d of the protrusion 32 includes a flat top surface 32d1 and an inclined top surface 32d2, which is part of the peripheral region 36, which is an inclined surface. The flat top surface 32d1 is a part of the top surface 32d of the protrusion 32 that extends substantially parallel to the main surface 22. The inclined top surface 32d2 is a part of the top surface 32d of the protrusion 32 that extends inclined with respect to the main surface 22. The inclined top surface 32d2 is a region of the top surface 32d that is radially inward and adjacent to the flat top surface 32d1. The boundary between the flat top surface 32d1 and the inclined top surface 32d2 may be a step or it may be a smooth continuity. Also, as shown in Figures 6(b) and 6(c), at one end of the protrusion 32 on the hole 24 side in the orthogonal direction, the protrusion height of the protrusion 32 is zero. In other words, the protrusion 32 terminates at the inner edge of the uneven region 30 (the part on the dashed line B in Figure 6(a)).

[0063] In this embodiment, when the coil end 20a and the busbar 50a are connected, at least a portion of the inclined peripheral region 36 is spaced apart from a portion of the surface of the busbar 50a in the thickness direction of the coil end 20a. As a result, a portion of the area around the hole 24 in the coil end 20a is less susceptible to stress from the busbar 50a and the screw 40. Therefore, deformation such that a portion of the area around the hole 24 in the coil end 20a is crushed and spreads inward into the hole 24 is suppressed. Specifically, at least a portion of the peripheral region 36 close to the hole 24 is spaced apart from the surface of the busbar 50a. The entire peripheral region 36 may be spaced apart from the busbar 50a. Alternatively, the entire peripheral region 36 may be in contact (pressure-contact or abutment) with the surface of the busbar 50a.

[0064] As described above, the uneven region 30 may include the entire surrounding region 36. That is, as shown in Figure 7, the uneven structure 30a may be formed from the outer edge to the inner edge of the coil end 20a. In the coil end 20a shown in Figure 7, the inclined top surface 32d2 widens as it approaches the hole 24. Specifically, a portion of the radially outer side of the inclined top surface 32d2 is sandwiched between the flat top surface 32d1 in the width direction of the convex ridge 32. In other words, the boundary between the flat top surface 32d1 and the inclined top surface 32d2 is a curve that is convex in the direction away from the hole 24 in the orthogonal direction.

[0065] The inductor 1 of this embodiment may have the same features as described in the first embodiment. For example, it may have the following features: The uneven structure 30a may be formed by two or more protrusions 32 and bottomed grooves 34 that are aligned with each other. The dimension of the top surface 32d of the protrusion 32 in the width direction may be larger than the dimension of the protrusion 32 in the direction in which the protrusion 32 is projected. The protrusions 32 and grooves 34 may extend along an orthogonal direction (left-right direction in the figure). When viewed from the direction through the hole 24, the first side surface 23 may be a curved surface that bulges outwards in the orthogonal direction from the inside to the outside of the coil end 20a. When viewed from the direction through the hole 24, the amount of bulging of the first side surface 23, which is a curved surface, may be larger than the amount of bulging of the second side surface 25 in the direction from the inside to the outside of the coil end 20a in the end extension direction.

[0066] In the second embodiment, the protruding height of the ridge 32 decreases as it approaches the hole 24, but alternatively, the protruding height of the ridge 32 does not have to change as it approaches the hole 24. In Figure 5(b), the top surface 32d of the ridge 32 is a flat surface up to one end of the top surface 32d on the hole 24 side.

[0067] <Third Embodiment> Figures 8(a) and 8(b) are cross-sectional views (cross-sectional views along the end extension direction) showing an example of the uneven structure according to this embodiment. First, the outline of the inductor 1 of this embodiment will be described.

[0068] In the inductor 1 of this embodiment, as described above, an uneven region 30 having an uneven structure 30a is formed on the connection surface 22a around the hole 24 (see Figure 4(a)).

[0069] Next, the inductor 1 and electrical equipment 100 of this embodiment will be described in detail. The inductor 1 of this embodiment differs from that of the first embodiment in the shape of the protrusions 32 in the uneven structure 30a.

[0070] As described in the first embodiment, the electrical device 100 includes an inductor 1 and a conductive member 50. The conductive member 50 is a member electrically connected to the end 20 of the conductor portion 10. Also, as shown in Figure 8, the protrusion 32 includes a protruding end 32a, a base end 32b, and an intermediate portion 32c. The protruding end 32a is a part of the protrusion 32 that contacts the conductive member 50. The base end 32b is a part of the protrusion 32 that is closer to the base end in the protruding direction of the protrusion 32 than the protruding end 32a. The intermediate portion 32c is a part of the protrusion 32 located between the protruding end 32a and the base end 32b. In this embodiment, the intermediate portion 32c is a part adjacent to the protruding end 32a in the thickness direction (protruding direction) of the hole 24. In particular, the intermediate portion 32c is a part having a width dimension equal to or smaller than the width dimension of the protruding end 32a. Furthermore, the base end portion 32b is a part of the protrusion 32 that includes the base end of the protrusion 32. In this embodiment, the base end portion 32b is a part adjacent to the intermediate portion 32c in the direction of penetration of the hole 24. Alternatively, the base end portion 32b may be a part that includes only the base end of the protrusion 32 or only the vicinity of the base end, and may not be adjacent to the intermediate portion 32c in the direction of penetration. Also, as described in the first embodiment, the top of the protruding end portion 32a is a planar top surface 32d.

[0071] As shown in Figure 8(a) or Figure 8(b), in this embodiment, the dimension of the intermediate portion 32c in the width direction of the protrusion 32 (width dimension L13) is smaller than the dimension of the base portion 32b in the width direction (width dimension L11). Also, the dimension of the intermediate portion 32c in the width direction (width dimension L13) is the same as or smaller than the dimension of the top surface 32d in the width direction (width dimension L12). Here, the width dimension of a predetermined part of the protrusion 32 is the maximum width dimension of that predetermined part. Specifically, in Figure 8(a), the width dimension L12 of the top surface 32d is equal to the width dimension L13 of the intermediate portion 32c, and the width dimension L11 of the base portion 32b is larger than both the width dimension L12 of the top surface 32d and the width dimension L13 of the intermediate portion 32c. Also, in Figure 8(b), the width dimension L13 of the intermediate portion 32c is smaller than both the width dimension L12 of the top surface 32d and the width dimension L11 of the base portion 32b. Furthermore, in Figure 8(b), the width dimension L12 of the top surface 32d is smaller than the width dimension L11 of the base end portion 32b. In this embodiment, the width dimension L12 of the top surface 32d is also the width dimension of the protruding end portion 32a. Figure 8(b) illustrates a configuration in which the top surface 32d protrudes beyond the intermediate portion 32c on both sides in the width direction of the protrusion 32, but it is not limited to this configuration. The top surface 32d may protrude beyond the intermediate portion 32c on only one side in the width direction of the protrusion 32, and the width dimension L12 may be larger than the width dimension L13.

[0072] As described above, because the width dimension L13 of the intermediate portion 32c is less than or equal to the width dimension L12 of the top surface 32d, the protruding end 32a (top surface 32d) can be pressed firmly against the busbar 50a even when the torque applied when tightening the screw 40 exceeds a predetermined value, compared to the case where the width dimension L13 of the intermediate portion 32c is larger than the width dimension L12 of the top surface 32d. Specifically, because the width dimension L12 of the top surface 32d is greater than or equal to the width dimension L13 of the intermediate portion 32c, even if the back surface 22d of the coil end 20a receives a large frictional force from the head of the rotating screw 40, the protrusion 32 is prevented from shifting laterally relative to the busbar 50a, and when the screw 40 is tightened, the protruding end 32a can deform into a shape that follows the busbar 50a while remaining directly facing the busbar 50a. This increases the contact area between the busbar 50a and the top surface 32d, and improves the connection between the busbar 50a and the top surface 32d. In particular, as shown in Figure 8(b), the above-mentioned effect is more pronounced when the width dimension L13 of the intermediate portion 32c is smaller than the width dimension L12 of the top surface 32d. Furthermore, because the width dimension L13 of the intermediate portion 32c is smaller than the width dimension L11 of the base end portion 32b, deformation such as the protrusion 32 unexpectedly bending or breaking at the base end portion 32b when the screw 40 is tightened is suppressed. As a result, the protrusion 32 can be pressed straight against the busbar 50a in the protruding direction.

[0073] In this embodiment, the top surface 32d is in contact with the surface of the busbar 50a (see Figure 2(b)). The base end 32b and the intermediate portion 32c are spaced apart from the surface of the busbar 50a.

[0074] <First Modification> In the above-described embodiment, the width dimension of the protrusion 32 or groove 34 was approximately constant from one end to the other, but is not limited to this. The protrusion 32 or groove 34 may have regions with different width dimensions from each other. For example, as shown in Figure 9, the protrusion 32 (particularly the top surface 32d of the protrusion 32) includes a wide portion 32g with a larger width dimension and a narrow portion 32h with a smaller width dimension. Here, the wide portion 32g is a portion of the top surface 32d of the protrusion 32 that is wider than other portions (e.g., the narrow portion 32h). Also, the narrow portion 32h is a portion of the top surface 32d of the protrusion 32 that is narrower than other portions (e.g., the wide portion 32g). In Figure 9, the wide portion 32g and the narrow portion 32h are arranged alternately in the direction of extension of the protrusion 32 (orthogonal direction in Figure 9). As described above, the top surface 32d of the protrusion 32 has a complex shape including a wide portion and a narrow portion, so that even if the surface of the busbar 50a is complexly deformed and has irregularities, the protrusion 32 can easily come into contact with the surface of the busbar 50a. As shown in Figure 9, in particular, in the protrusion 32f that does not straddle the hole 24, the wide portion 32g and the narrow portion 32h are arranged alternately in the direction of extension of the protrusion 32f.

[0075] In this modified example, as shown in Figure 9, the outer edge of the convex 32 (the outer edge defining the width of the top surface 32d of the convex 32) is wave-shaped. Here, the outer edge of the convex 32 (the outer edge defining the width of the top surface 32d of the convex 32) coincides with the opening of the groove 34. Therefore, in the wide portion 32g, the central part in the direction of extension (orthogonal direction) of the convex 32 is the widest, and in the narrow portion 32h, the central part in the direction of extension of the convex 32 is the most concave in the width. Furthermore, the outer edge of the wide portion 32g and the outer edge of the narrow portion 32h are smoothly connected at their boundary.

[0076] Furthermore, as shown in Figure 9, the groove 34 (especially the opening of the groove 34) includes a wide portion 34a with a larger width dimension and a narrow portion 34b with a smaller width dimension. Here, the wide portion 34a is a portion of the opening of the groove 34 that is wider than other portions (e.g., the narrow portion 34b). The narrow portion 34b is a portion of the opening of the groove 34 that is narrower than other portions (e.g., the wide portion 34a). In Figure 9, the wide portion 34a and the narrow portion 34b are arranged alternately in the extending direction of the groove 34 (orthogonal direction in Figure 9). As shown in Figure 9, in particular, in the groove 34f that does not straddle the hole 24, the wide portion 34a and the narrow portion 34b are arranged alternately in the extending direction of the groove 34f.

[0077] As shown in Figure 9, in the direction perpendicular to the extending direction of the convex ridge 32 and the concave groove 34 (end extension direction), the narrow portion 32h of the convex ridge 32 is adjacent to the wide portion 34a of the concave groove 34, and the wide portion 32g of the convex ridge 32 is adjacent to the narrow portion 34b of the concave groove 34.

[0078] As shown in Figure 9, the width dimension (width L21) of the groove 34e terminating at the inner edge of the coil end 20a (the inner wall surface defining the hole 24) decreases as it approaches the hole 24 in the direction of extension of the groove 34e. In particular, the width dimension (width L21) of the groove 34e terminating at the inner edge of the coil end 20a decreases as it approaches the hole 24, from the center of the groove 34e to one end of the groove 34e on the hole 24 side in the direction of extension of the groove 34e. Also, the width dimension (width L22) of the ridge 32e terminating at the inner edge of the coil end 20a increases as it approaches the hole 24 in the direction of extension of the ridge 32e. In particular, the widthwise dimension of the protrusion 32e that terminates at the inner edge of the coil end 20a increases as it approaches the hole 24, from the central part of the protrusion 32e in the direction of extension of the protrusion 32e to the end of the protrusion 32e on the hole 24 side.

[0079] <Second Modification> In the first to third embodiments described above, the inner wall surface defining the hole 24 was a smooth curved surface, but it is not limited to this. As shown in Figure 10, a part of the inner wall surface defining the hole 24 may protrude toward the interior of the hole 24. In other words, a part of the inner wall surface defining the hole 24 may protrude inward in the radial direction of the hole 24. To put it another way, a part of the inner wall surface defining the hole 24 is recessed toward the outward radial direction of the hole 24 (towards the interior of the coil end 20a).

[0080] As shown in Figure 10, more specifically, the inner wall surface defining the hole 24 is upright at an angle of approximately 90 degrees perpendicular to the main surface 22 on the back surface 22d side of the coil end 20a, and on the side of the connecting surface 22a, it is inclined outward in the radial direction at a somewhat steep angle of more than 45 degrees. On the side of this connecting surface 22a, the portion of the inner wall surface where the groove 34 ends protrudes inward in the radial direction more than other portions adjacent to that portion in the circumferential direction of the inner wall surface (for example, the portion where the protrusion 32 ends). Also, the portion of the inner wall surface defining the hole 24 where the protrusion 32 ends is recessed outward in the radial direction more than other portions adjacent to that portion in the circumferential direction of the inner wall surface (for example, the portion where the groove 34 ends). In this way, because a portion of the inner wall surface where the protrusion 32 terminates is located radially outside the hole 24, even when the screw 40 is tightened and the protrusion 32 is crushed, causing the coil end 20a to expand inward into the hole 24, the hole 24 is prevented from becoming smaller.

[0081] It should be noted that the present invention is not limited to the embodiments or modifications described above, but also includes various modifications, improvements, and other forms as long as the objectives of the present invention are achieved.

[0082] The above embodiments encompass the following technical concepts: (1) An inductor having a conductor portion that generates inductance, including an end portion, wherein the end portion is a flat plate having two opposing main surfaces, the end portion has a hole penetrating in the thickness direction, and on one of the main surfaces of the end portion, an uneven region having an uneven structure is formed around the hole. (2) The inductor according to (1), wherein the uneven structure is formed by two or more convex ridges and a bottomed groove. (3) The inductor according to (2), wherein the top of the convex ridge is a planar top surface, the dimension of the top surface in the width direction of the convex ridge is greater than the dimension of the convex ridge in the projection direction of the convex ridge. (3-1) The inductor according to (2), wherein the width dimension of the top surface of the convex ridge is greater than the width dimension of the bottom of the groove in the width direction. (3-2) The inductor according to (2) or (3), wherein the pitch of two grooves side by side is greater than the dimension of the convex ridge in the projection direction. (3-3) The inductor according to (2) or (3), wherein the protrusions are defined by a top surface and a pair of inclined surfaces, the inclined surfaces extending at an angle with respect to the thickness direction of the end and the extension direction of the top surface, and the smaller of the angles formed by the pair of inclined surfaces defining one protrusion is 90 degrees or more. (3-4) The inductor according to (2) or (3), wherein the grooves are defined by a bottom surface and a pair of inclined surfaces, the inclined surfaces extending at an angle with respect to the thickness direction of the end and the extension direction of the bottom surface, and the smaller of the angles formed by the pair of inclined surfaces defining one groove is 90 degrees or more. (4) The inductor according to (2), wherein the protrusions and grooves extend along an orthogonal direction perpendicular to the end extension direction, which is the direction connecting the base end and the tip end of the end. (5) The inductor according to (4), wherein the surface of the end includes a first side surface facing the orthogonal direction, and when viewed from the direction through the hole, the first side surface is a curved surface that bulges outwards from the inside to the outside of the end in the orthogonal direction. (5-1) The inductor according to (5), wherein when viewed from the direction through the hole, the part of the first side surface that bulges outwards mostwards from the inside to the outside of the end in the orthogonal direction overlaps with the hole in the orthogonal direction.(6) The inductor according to (5), wherein the surface of the end includes a second surface facing the direction of the end extension, and when viewed from the through direction, the amount of bulging of the first surface, which is a curved surface, is greater than the amount of bulging of the second surface in the direction from the inside to the outside of the end in the direction of the end extension. (6-1) The inductor according to (5), wherein the first surface 23 bulges in the direction from the inside to the outside of the end in a perpendicular direction, while the second surface is a flat surface, or bulges in the direction from the inside to the outside of the coil end in the direction of the end extension, and when viewed from the direction of the hole extension, the amount of bulging of the first surface, which is a curved surface, is greater than the amount of bulging of the second surface. (6-2) The inductor according to (5), wherein when viewed from the direction of the hole extension, the amount of bulging of the first surface, which is a curved surface, is greater than the amount of bulging in the radial direction of the hole on the inner wall surface defining the hole. (6-3) The inductor according to (5) or (6), wherein, when viewed in the direction of the end extension, the first side surface is a curved surface that bulges outward in the direction perpendicular to the coil end. (7) The inductor according to any one of (4) to (6), wherein in a single protrusion, the protruding height of the protrusion decreases toward the hole in the direction perpendicular to the hole. (7-1) The inductor according to (7), wherein in the single protrusion, the top surface of the protrusion is inclined toward the back surface in the direction of penetration of the hole toward the hole. (8) The inductor according to (7), wherein the top of the protrusion is a planar top surface, the uneven region includes at least a portion of the peripheral region surrounding the hole, the peripheral region is an inclined surface that is inclined toward the other main surface in the direction of penetration of the hole toward the hole and includes the top surface of the protrusion. (8-1) The inductor according to (8), wherein at least a portion of the peripheral region that is an inclined surface is spaced apart in the thickness direction from a portion of the surface of the conductive material.(9) An electrical device comprising an inductor as described in any of (2) to (8), and a conductive member electrically connected to the end, wherein the protrusion includes a protruding end that contacts the conductive member, a base end which is a part of the protruding direction of the protrusion that is closer to the base end than the protruding end, and an intermediate portion located between the protruding end and the base end, the top of the protruding end is a planar top surface, the dimensions of the intermediate portion in the width direction of the protrusion are smaller than the dimensions of the base end in the width direction, and the dimensions of the intermediate portion in the width direction are the same as or smaller than the dimensions of the top surface in the width direction. (10) A coil including an end, wherein the end is a flat plate having two opposing main surfaces, the end has a hole that penetrates in the thickness direction, and on one of the main surfaces of the end, an uneven region having an uneven structure around the hole is formed. (11) The inductor according to (1), wherein the top surface of the protrusion includes a wide portion and a narrow portion having a width smaller than the wide portion, and the wide portion and the narrow portion are arranged alternately in the direction of extension of the protrusion. (12) The inductor according to (1), wherein the widthwise dimension of the groove terminating at the inner edge of the end of the conductor portion decreases as it approaches the hole in the direction of extension of the groove. (13) The inductor according to (1), wherein the portion of the inner wall surface defining the hole to which the protrusion terminates is recessed radially outward in the circumferential direction of the inner wall surface than other portions adjacent to that portion.

[0083] 1 Inductor 10 Conductor part 10a Coil 20 End part 20a Coil end part 20b Adjacent part 22 Main surface 22a Connection surface 22d Back surface 23 First side surface 24 Hole 25 Second side surface 30 Uneven area 30a Uneven structure 32 (32e, 32f) Rib 32a Protruding end part 32b Base end part 32c Intermediate part 32d Top surface 32d1 Flat top surface 32d2 Inclined top surface 32g Wide part 32h Narrow part 34 (34e, 34f) Groove 34a Wide part 34b Narrow part 36 Peripheral area 40 Screw 50 Conductive member 50a Busbar 60 Case 100 Electrical equipment

Claims

1. An inductor having a conductor portion that generates inductance, including an end portion, wherein the end portion is a flat plate shape having two opposing main surfaces, the end portion has a hole that penetrates in the thickness direction, and on one of the main surfaces of the end portion, an uneven region having an uneven structure is formed around the hole.

2. The inductor according to claim 1, wherein the uneven structure is formed by two or more convex ridges and bottomed grooves that are aligned with each other.

3. The inductor according to claim 2, wherein the top of the protrusion is a planar top surface, and the dimension of the top surface in the width direction of the protrusion is greater than the dimension of the protrusion in the direction of projection of the protrusion.

4. The inductor according to claim 2, wherein the protrusions and grooves extend along an orthogonal direction perpendicular to the end extension direction, which is the direction connecting the base end and the tip end of the end.

5. The inductor according to claim 4, wherein the surface of the end portion includes a first side surface facing the orthogonal direction, and when viewed from the direction of penetration of the hole, the first side surface is a curved surface that bulges outward from the inside to the outside of the end portion in the orthogonal direction.

6. The inductor according to claim 5, wherein the surface of the end includes a second side facing the direction of the end extension, and when viewed from the through direction, the amount of bulging of the first side which is a curved surface is greater than the amount of bulging of the second side in the direction from the inside to the outside of the end in the direction of the end extension.

7. The inductor according to any one of claims 4 to 6, wherein in one of the protrusions, the height of the protrusion of the protrusion decreases toward the hole in the orthogonal direction.

8. The inductor according to claim 7, wherein the top of the protrusion is a planar top surface, the uneven region includes at least a portion of the peripheral region surrounding the hole, and the peripheral region is an inclined surface that slopes toward the other main surface side in the direction of penetration of the hole as it approaches the hole, and includes the top surface of the protrusion.

9. An electrical device comprising an inductor according to any one of claims 2 to 8 and a conductive member electrically connected to the end, wherein the protrusion includes a protruding end that contacts the conductive member, a base end that is a part of the protruding direction of the protrusion that is closer to the base end than the protruding end, and an intermediate portion located between the protruding end and the base end, the top of the protruding end is a planar top surface, the dimensions of the intermediate portion in the width direction of the protrusion are smaller than the dimensions of the base end in the width direction, and the dimensions of the intermediate portion in the width direction are the same as or smaller than the dimensions of the top surface in the width direction.

10. A coil including an end, wherein the end is a flat plate having two opposing main surfaces, the end has a hole penetrating in the thickness direction, and on one of the main surfaces of the end, an uneven region having an uneven structure is formed around the hole.

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