Patent Publication Number: US-11043327-B2

Title: Inductor component

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims benefit of priority to Japanese Patent Application No. 2017-086204, filed Apr. 25, 2017, the entire content of which is incorporated herein by reference. 
     BACKGROUND 
     Technical Field 
     The present disclosure relates to an inductor component including a core and a wire wound around the core. 
     Background Art 
     Various types of inductor components are mounted in electronic devices. A wire-wound inductor component includes a core and a wire wound around the core. The end portions of the wire are connected to terminal electrodes formed on the core (see, for example, Japanese Unexamined Patent Application Publications Nos. 2002-280226 and 10-321438). Each terminal electrode is connected to a pad by, for example, solder, the pad being formed on a circuit board on which the inductor component is mounted. 
     SUMMARY 
     Electronic devices, such as cellular phones, have become smaller, and there has been a demand for smaller inductor components to be mounted in such an electronic device. When an inductor component is reduced in size, the thickness of the wire is reduced accordingly, and there is a risk that breakage of the wire, for example, will occur. 
     The present disclosure provides an inductor component including a wire that does not easily break. 
     According to one embodiment of the present disclosure, an inductor component includes a core including a substantially column-shaped shaft and a support formed on an end portion of the shaft; a terminal electrode formed on the support; and a wire wound around the shaft and including an end portion connected to the terminal electrode. The support includes a first ridge that is rounded at a boundary between an inner face of the support and a bottom face of the support, and a second ridge that is rounded at a boundary between the bottom face and an end face of the support. A radius of curvature of the first ridge is greater than a radius of curvature of the second ridge. With this structure, the wire is curved with a large radius of curvature at the first ridge, so that the occurrence of breakage of the wire can be reduced. 
     In the above-described inductor component, the radius of curvature of the second ridge is preferably greater than or equal to about 20 μm. With this structure, the occurrence of breakage of the wire can be more reliably reduced. 
     In the above-described inductor component, the radius of curvature of the first ridge is preferably greater than the radius of curvature of the second ridge by an amount greater than or equal to about 9% of the radius of curvature of the second ridge. With this structure, the occurrence of breakage of the wire included in the inductor component can be more reliably reduced. 
     In the above-described inductor component, the inner face of the support is preferably vertical between the first ridge and the shaft. This structure provides a larger space for winding the wire in the region near the inner face of the support. 
     In the above-described inductor component, preferably, the support includes a third ridge that is rounded at a boundary between a top face of the support and the inner face, and a fourth ridge that is rounded at a boundary between the top face and the end face, and a radius of curvature of the third ridge is greater than a radius of curvature of the fourth ridge. With this structure, the manufacturing process of the inductor component can be facilitated. 
     In the above-described inductor component, preferably, a length dimension of the inductor component including the core and the terminal electrode is less than or equal to about 1.0 mm, a width dimension of the inductor component including the core and the terminal electrode is less than or equal to about 0.6 mm, and a height dimension of the inductor component including the core and the terminal electrode is less than or equal to about 0.8 mm With this structure, the size of the inductor component is reduced. Accordingly, the effect of reducing the occurrence of breakage of the wire can be more effective. 
     A height dimension of the above-described inductor component including the core and the terminal electrode is preferably greater than a width dimension of the inductor component including the core and the terminal electrode. With this structure, the height of the terminal electrode can be increased relative to a certain mounting area, and the surface area of the terminal electrode can be increased accordingly. When the surface area is increased, the terminal electrode can be strongly connected to a circuit board. In other words, the fixing force between the inductor component and the circuit board can be increased. 
     In the above-described inductor component, preferably, the terminal electrode includes a bottom electrode section on the bottom face of the support, a side electrode section on a side face of the support, and an end electrode section on the end face of the support, and an end portion of the end electrode section adjacent to the side face is higher than an end portion of the side electrode section adjacent to the end face. With this structure, the surface area of the end electrode section can be increased. 
     In the above-described inductor component, a central portion of the end electrode section is preferably higher than the end portion of the end electrode section. In this structure, the surface area of the end electrode section is greater than that in the case where the central portion and the end portion have the same height. 
     In the above-described inductor component, preferably, a top edge of the end electrode section is substantially upwardly convex arc-shaped. With this structure, the surface area of the end electrode section can be further increased. 
     In the above-described inductor component, a height of the side electrode section preferably increases from the inner face of the support toward the end face of the support. With this structure, the terminal electrode is lower at the end adjacent to the inner face than at the end adjacent to the end face. Therefore, even when the height of the end electrode section is increased, the risk of interference between the wire and solder in the region near the inner face can be reduced in the mounting process. 
     In the above-described inductor component, the end portion of the side electrode section adjacent to the end face preferably is higher than a bottom face of the shaft. With this structure, the end electrode section connected to the side electrode section can be formed to have a larger surface area than that in a common terminal electrode. 
     In the above-described inductor component, preferably, the side electrode section includes two portions having different inclinations, and an inclination of one of the two portions that is adjacent to the end face is greater than an inclination of other of the two portions that is adjacent to the inner face of the support. With this structure, the design flexibility of the terminal electrode of the inductor component and the land pattern on the circuit board can be increased. 
     In the above-described inductor component, preferably, the side electrode section includes two portions having different inclinations, and an inclination one of the two portions that is adjacent to the inner face of the support is greater than an inclination of other of the two portions that is adjacent to the end face. With this structure, the design flexibility of the terminal electrode of the inductor component and the land pattern on the circuit board can be increased. 
     In the above-described inductor component, the terminal electrode preferably includes a ridge electrode section between the side electrode section and the end electrode section on a ridge at a boundary between the side face and the end face, the ridge electrode section having an inclination greater than an inclination of the side electrode section. With this structure, the surface area of the end electrode section can be further increased. 
     In the above-described inductor component, preferably, the terminal electrode includes an underlying layer on a surface of the support and a plated layer on a surface of the underlying layer, and a maximum thickness of the underlying layer on the end face of the support is greater than a maximum thickness of the underlying layer on the bottom face of the support. With this structure, the adhesion between the underlying layer on the end face and the end face can be increased, and the surface area of the end electrode section can be increased. 
     Preferably, the above-described inductor component further includes a cover member that covers a top face of the support, and a width dimension of the inductor component including the core and the terminal electrode is greater than a width dimension of the cover member. The inductor component having this structure can be easily mounted by using the cover member. In addition, the inductor component can be easily placed in a stable position in the mounting process. Furthermore, the gap between the inductor component mounted on the circuit board and a component mounted adjacent to the inductor component can be increased at the top side. Thus, the risk of interference between the components due to, for example, tilting of the components can be reduced. 
     A length dimension of the above-described inductor component including the core and the terminal electrode is preferably greater than a length dimension of the cover member. The inductor component having this structure can be more easily placed in a stable position in the mounting process. 
     Preferably, the above-described inductor component further includes a cover member that does not cover a top face of the support but covers an upper face of the shaft. The inductor component having this structure can be easily mounted by using the cover member. In addition, the gap between the inductor component mounted on the circuit board and a component mounted adjacent to the inductor component can be increased at the top side. Thus, the risk of interference between the components due to, for example, tilting of the components can be reduced. 
     In the above-described inductor component, preferably, the core includes another support that are formed on another end portion of the shaft, the inductor component further includes another terminal electrode formed on the another support, and the terminal electrode on the support and the another terminal electrode on the another support have different shapes. With this structure, the design flexibility of the terminal electrodes of the inductor component and the land pattern on the circuit board can be increased. 
     In the inductor component according to the embodiments of the present disclosure, the occurrence of breakage of the wire can be reduced. 
     Other features, elements, characteristics and advantages of the present disclosure will become more apparent from the following detailed description with reference to the attached drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  is a front view of an inductor component according to a first embodiment, and  FIG. 1B  is an end view of the inductor component; 
         FIG. 2  is a perspective view of the inductor component according to the first embodiment; 
         FIG. 3  is a schematic perspective view illustrating cross sections of a core; 
         FIG. 4  is a side view of the core; 
         FIG. 5  is an enlarged sectional view of a terminal electrode; 
         FIGS. 6A to 6C  are schematic diagrams illustrating steps for forming the terminal electrode; 
         FIG. 7A  is a side view of the inductor component according to the first embodiment, and  FIG. 7B  is a side view of an inductor component of a comparative example; 
         FIG. 8A  is a front view of an inductor component according to a second embodiment, and  FIG. 8B  is an end view of the inductor component according to the second embodiment; 
         FIG. 9  is a perspective view of the inductor component according to the second embodiment; 
         FIG. 10  is a graph showing the frequency-impedance characteristics of the inductor component according to the second embodiment; 
         FIG. 11  is a side view of an inductor component according to a modification; 
         FIG. 12  is a side view of an inductor component according to another modification; 
         FIG. 13  is a side view of an inductor component according to another modification; 
         FIG. 14  is a side view of an inductor component according to another modification; 
         FIG. 15  is a side view of an inductor component according to another modification; 
         FIG. 16  is a schematic perspective view of a core according to another modification; and 
         FIG. 17  is a photograph of an end face of a core. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure will now be described. 
     In the accompanying drawings, the constituent elements may be enlarged to facilitate understanding. The dimensional ratios between the constituent elements may differ from the actual ratios or those in other figures. Although some constituent elements are hatched in sectional views to facilitate understanding, hatching may be omitted. 
     First Embodiment 
     A first embodiment will now be described. 
     An inductor component  10  illustrated in  FIGS. 1A, 1B , and  FIG. 2  is, for example, a surface-mount inductor component to be mounted on, for example, a circuit board. The inductor component  10  may be used in various devices, such as smart phones and wrist-worn mobile electronic devices (for example, smart watches). 
     The inductor component  10  according to the present embodiment includes a core  20 , a pair of terminal electrodes  50 , and a wire  70 . The core  20  includes a shaft  21  and a pair of supports  22 . The shaft  21  is substantially rectangular parallelepiped shaped (rectangular prism shaped). The supports  22  extend perpendicularly to the longitudinal direction of the shaft  21  from both ends of the shaft  21 . The shaft  21  is supported parallel to a circuit board by the supports  22 . The supports  22  are formed integrally with the shaft  21  at both ends of the shaft  21 . 
     The terminal electrodes  50  are formed on the respective supports  22 . The wire  70  is wound around the shaft  21  so as to form a single layer on the shaft  21 . Both end portions of the wire  70  are connected to the respective terminal electrodes  50 . The inductor component  10  is a wire-wound inductor component. 
     The inductor component  10  is substantially rectangular parallelepiped shaped. In this specification, the term “rectangular parallelepiped shape” covers the shapes of rectangular parallelepipeds having beveled or rounded corners or ridges. Also, the principal faces and side faces may be uneven either locally or over the entire area thereof. The term “rectangular parallelepiped shape” also covers the shapes in which opposing faces are not exactly parallel but are somewhat inclined relative to each other. 
     In this specification, the longitudinal direction of the shaft  21  is defined as a “length direction Ld”. Among the directions perpendicular to the “length direction Ld”, the vertical direction in  FIGS. 1A and 1B  is defined as a “height direction (thickness direction) Td”, and the direction perpendicular to the “length direction Ld” and the “height direction Td” (horizontal direction in  FIG. 1B ) is defined as a “width direction Wd”. In this specification, among the directions perpendicular to the length direction, the “width direction” is the direction parallel to the circuit board in the state in which the inductor component  10  is mounted on the circuit board. 
     The dimension of the inductor component  10  in the length direction Ld (length dimension L 1 ) is preferably greater than about 0 mm and less than or equal to about 1.0 mm (i.e., from greater than about 0 mm to about 1.0 mm). In the present embodiment, the length dimension L 1  of the inductor component  10  is, for example, about 0.7 mm. 
     The dimension of the inductor component  10  in the width direction Wd (width dimension W 1 ) is preferably greater than about 0 mm and less than or equal to about 0.6 mm (i.e., from greater than about 0 mm to about 0.6 mm). The width dimension W 1  is preferably less than or equal to about 0.36 mm, and more preferably less than or equal to about 0.33 mm. In the present embodiment, the width dimension W 1  of the inductor component  10  is, for example, about 0.3 mm. 
     The dimension of the inductor component  10  in the height direction Td (height dimension T 1 ) is preferably greater than about 0 mm and less than or equal to about 0.8 mm (i.e., from greater than about 0 mm to about 0.8 mm). In the present embodiment, the height dimension T 1  of the inductor component  10  is, for example, about 0.5 mm. 
     As illustrated in  FIG. 2 , the shaft  21  is substantially rectangular parallelepiped shaped and extends in the length direction Ld. The supports  22  are plate-shaped and are thin in the length direction Ld. The supports  22  are rectangular parallelepiped shaped and are longer in the height direction Td than in the width direction Wd. 
     The supports  22  protrude around the shaft  21  in the height direction Td and the width direction Wd. More specifically, when viewed in the length direction Ld, each support  22  is shaped so as to protrude from the shaft  21  in the height direction Td and the width direction Wd. 
     Each support  22  includes an inner face  31  and an end face  32  that oppose each other in the length direction Ld; a pair of side faces  33  and  34  that oppose each other in the width direction Wd; and a top face  35  and a bottom face  36  that oppose each other in the height direction Td. The inner face  31  of one support  22  opposes the inner face  31  of the other support  22 . As illustrated in the drawings, in this specification, the term “bottom face” means a face that opposes the circuit board when the inductor component is mounted on the circuit board. In particular, the bottom face of each support is the face on which a terminal electrode is formed. The term “top face” means a face that opposes the “bottom face”. The term “end face” means the face of each support that faces away from the shaft. The term “side face” means a face adjacent to a bottom face and an end face. 
     Examples of the material of the core  20  include magnetic materials (for example, nickel-zinc (Ni—Zn) ferrites and manganese-zinc (Mn—Zn) ferrites), alumina, and metal magnetic substances. The core  20  can be formed by compression molding and sintering by using powder of the above-mentioned materials. 
     As illustrated in  FIG. 4 , each support  22  includes a ridge  41  (first ridge) at the boundary between the inner face  31  and the bottom face  36 , and a ridge  42  (second ridge) at the boundary between the end face  32  and the bottom face  36 . The surfaces of the ridges  41  and  42  are curved convexly toward the outside of the core  20 , and are substantially cylindrical (convexly cylindrical). Similarly, each support  22  includes a ridge  43  (third ridge) at the boundary between the top face  35  and the inner face  31 , and a ridge  44  (fourth ridge) at the boundary between the top face  35  and the end face  32 . The surfaces of the ridges  43  and  44  are curved convexly toward the outside of the core  20 , and are substantially cylindrical (convex cylindrical). Although not illustrated in  FIG. 4 , each support  22  also includes rounded ridges at the boundaries between the inner face  31  and the side faces  33  and  34  and rounded ridges at the boundaries between the end face  32  and the side faces  33  and  34 . 
     The substantially cylindrical surfaces of the ridges  41  to  44  are arc-shaped in side view. The radii of curvature of the ridges  41  and  43  adjacent to the inner face  31  are greater than those of the ridges  42  and  44  adjacent to the end face  32 . For example, the radii of curvature of the ridges  41  and  43  are preferably greater than those of the ridges  42  and  44  by about 9% or more of the radii of curvature of the ridges  42  and  44 . Multiple inductor components having this structure caused no wire breakage. The radii of curvature of the ridges  42  and  44  are preferably greater than or equal to about 20 μm. For example, the radii of curvature of the ridges  42  and  44  are preferably in the range of about 20 μm to about 40 μm, and the radii of curvature of the ridges  41  and  43  are preferably in the range of about 25 μm to about 50 μm. 
     The radii of curvature of the ridges  41  to  44  are set so that the top face  35  and the bottom face  36  of the support  22  are substantially flat. A thickness dimension L 22  of the support  22  (thickness in the length direction Ld) is preferably in the range of about 50 μm to about 150 μm. For example, the thickness dimension of the support  22  is about 100 μm, the radius of curvature of the ridge  41  is about 40 μm, and the radius of curvature of the ridge  42  is about 35 μm. In the present embodiment, the radius of curvature of the ridge  43  adjacent to the inner face  31  is greater than the radius of curvature of the ridge  44  adjacent to the end face  32 . For example, the radius of curvature of the ridge  43  is about 40 μm, and the radius of curvature of the ridge  44  is about 35 μm. 
     When the radii of curvature of the ridges  41  and  43  adjacent to the inner face  31  are greater than those of the ridges  42  and  44  adjacent to the end face  32 , the manufacturing process of the inductor component  10  can be facilitated. The inductor component  10  includes the terminal electrodes  50  on the bottom faces  36  of the core  20 . For the reasons described below, each terminal electrode  50  is formed at the side at which the radius of curvature of the ridge adjacent to the inner face  31  is greater than that of the ridge adjacent to the end face  32 . If the above-described relationship between the radii of curvature is satisfied at only one of the top face  35  and the bottom face  36 , the side at which the terminal electrode  50  is to be formed needs to be determined, and the core  20  needs to be held in accordance with the result of the determination, which takes a long time. The core  20  according to the present embodiment enables the terminal electrode  50  to be formed thereon without the determination step, and thus the manufacturing process can be facilitated. In the present embodiment, among the two faces that oppose each other in the height direction Td, the face on which the terminal electrode  50  is formed is the bottom face  36 , and the face that opposes the bottom face  36  is the top face  35 . When it is not necessary to achieve the above-described effect, the radii of curvature of the ridges adjacent to the top face  35  do not need to satisfy the above-described relationship. 
     In the inductor component  10 , the terminal electrodes  50  are not formed on the top faces  35  of the supports  22 . In other words, the terminal electrodes  50  of the inductor component  10  are formed on the bottom faces  36 . The inductor component  10  having such a structure has a low center of gravity, and therefore can be easily placed in a stable position in the mounting process. When it is not necessary to achieve such an effect, the terminal electrodes  50  may be additionally formed on the top faces  35 . 
     In the inductor component  10 , the inner faces  31  of the supports  22  are perpendicular to the bottom faces  36 . In other words, the inner faces  31  of the supports  22  are vertical between the shaft  21  and the ridges  41 . This structure provides a larger region (space) for winding the wire  70  around the shaft  21  near the inner faces  31  of the supports  22 . 
     Referring to  FIG. 3 , the area of a cross section  21   a  of the shaft  21  taken perpendicular to the axial direction (length direction Ld) is preferably in the range of about 35% to about 75%, and more preferably about 40% to about 70%, of the area of a cross section  22   a  of each support  22  taken perpendicular to the axial direction. The area of the cross section  21   a  of the shaft  21  is more preferably in the range of about 45% to about 65%, and still more preferably in the range of about 50% to about 60%, of the area of the cross section  22   a  of each support  22 . In the present embodiment, the area of the cross section  21   a  of the shaft  21  is about 55% of the area of the cross section  22   a  of the support  22 . 
     When the ratio of the cross-sectional area of the shaft  21  to the cross-sectional area of each support  22  is set in a predetermined range as described above, the design flexibility of the inductor component  10  (core  20 ) can be increased by using the space between the shaft  21  and the end portions of the supports  22  in the directions perpendicular to the length direction Ld (width direction Wd and height direction Td). When, for example, the ratio of the cross-sectional area of the shaft  21  to the cross-sectional area of each support  22  is greater than a certain ratio, the strength of the core  20  can be increased. In addition, the amount of saturation of magnetic flux that passes through the core  20  can be increased, which leads to less degradation in characteristics. When the ratio of the cross-sectional area of the shaft  21  to the cross-sectional area of each support  22  is large, there is a risk that the wire  70  wound around the core  20  will protrude from the end portions of the supports  22 . 
     The design flexibility may be such that the position of the shaft  21  relative to each support  22  may be set. The characteristics of the inductor component  10  may be set in accordance with the position of the shaft  21 . For example, when the shaft  21  is at a high position, the amount of parasitic capacitance between the wire  70  and each of the wires and pads on the circuit board having the inductor component  10  mounted thereon can be reduced. Accordingly, the self-resonance frequency can be increased. When the shaft  21  is at a low position, the inner faces  31  of the supports  22  oppose each other over a large area above the shaft  21 . Therefore, magnetic flux is easily generated between the supports  22 . Accordingly, the inductance can be set to a desired value, and the impedance can be increased. 
     As illustrated in  FIGS. 1A and 1B , each terminal electrode  50  includes a bottom electrode section  51  formed on the bottom face  36  of the corresponding support  22 . The bottom electrode section  51  is formed over the entire area of the bottom face  36  of the support  22 . 
     Each terminal electrode  50  also includes an end electrode section  52  formed on the end face  32  of the corresponding support  22 . The end electrode section  52  is formed so as to cover a portion (lower portion) of the end face  32  of the support  22 . The end electrode section  52  is connected to the bottom electrode section  51  by a portion of the terminal electrode  50  on the ridge  42  between the end face  32  and the bottom face  36 . 
     As illustrated in  FIG. 1B , a central portion  52   a  of the end electrode section  52  is higher than an end portions  52   b  of the end electrode section  52  positioned in the width direction Wd. A top edge  52   c  of the end electrode section  52  is substantially upwardly convex arc-shaped. The end portion  52   b  of the end electrode section  52  adjacent to the side face  33  is higher than an end portion of a side electrode section  53  on the side face  33  adjacent to the end face  32 .  FIG. 17  is an enlarged photograph of the core and the end electrode section. 
     The ratio of a height Ta of the central portion  52   a  of the end electrode section  52  to a height Tb of the end portions  52   b  of the end electrode section  52  is preferably greater than or equal to about 1.1, and more preferably greater than or equal to about 1.2. In the present embodiment, the height ratio is greater than or equal to about 1.3. When viewed in a direction perpendicular to the end face  32 , the height of the end electrode section  52  is a length from the surface (bottom end) of the bottom electrode section  51  to the edge (top end) of the end electrode section  52  in the height direction Td. In particular, the height Tb of the end portions  52   b  is the height at the ends of the end face  32 , which is substantially flat, in the width direction Wd. 
     In  FIG. 1B , the ends of the substantially flat end face  32  are indicated by broken lines. The core  20  has a ridge that is rounded at the boundary between the side face  33  and the end face  32 . The ridge is formed by, for example, barrel finishing. The position of the bottom end varies at the ridge, and accordingly the height of the end electrode section  52  easily varies. Therefore, the end portions  52   b  of the end electrode section  52  are defined as the portions at the ends of the substantially flat end face  32  in the width direction Wd. In the case where the substantially flat end face  32  does not have clear ends, the end portions  52   b  may be defined as portions that are about 50 μm inward from the side faces  33  and  34  of the support  22  in  FIG. 1B . 
     The width dimension W 1  and the height dimension T 1  of the inductor component  10  are preferably such that the height dimension T 1  is greater than the width dimension W 1  (T 1 &gt;W 1 ). In such a case, the height of the end electrode section  52  can be increased relative to a certain mounting area, and the surface area of the end electrode section  52  can be increased accordingly. As a result, the fixing force can be increased. 
     As illustrated in  FIG. 1B , each terminal electrode  50  also includes side electrode sections  53  formed on the side faces  33  and  34  of the corresponding support  22 . As illustrated in  FIG. 1A , the side electrode sections  53  of the terminal electrodes  50  cover portions (lower portions) of the side faces  33  of the respective supports  22 . The side electrode sections  53  are connected to the bottom electrode sections  51  and the end electrode sections  52  by portions of the terminal electrodes  50  on the ridges. The side electrode sections  53  are formed so that the heights thereof gradually increase with increasing distances from the opposing inner faces  31  toward the end faces  32  of the supports  22 , that is, so that the top edges of the terminal electrodes  50  are inclined on the side faces  33  of the supports  22 . In the present embodiment, end portions of the side electrode sections  53  that are adjacent to the end faces  32  extend to a position higher than the bottom face of the shaft  21  with respect to the bottom face  36  of the corresponding support  22 . Although the side electrode sections  53  on the side faces  33  are illustrated in  FIG. 1A , the side electrode sections on the side faces  34  illustrated in  FIG. 1B  have a similar structure. As described above, the bottom electrode sections  51 , the end electrode sections  52 , and the side electrode sections  53  do not include portions of the terminal electrodes  50  on the ridges between the end faces  32 , the side faces  33  and  34 , and the bottom faces  36 . 
     As illustrated in  FIG. 5 , each terminal electrode  50  includes an underlying layer  61  on a surface of the core  20  and plated layers  62  and  63  that cover the underlying layer  61 . The maximum thickness of a portion of the underlying layer  61  on the end face  32  is greater than the maximum thickness of a portion of the underlying layer  61  on the bottom face  36 . 
     The underlying layer  61  is a metal layer containing, for example, silver (Ag) as a main component. The underlying layer  61  may additionally contain, for example, silica and resin. The plated layer  62  may be formed of, for example, a metal such as nickel (Ni) or copper (Cu), or an alloy such as Ni-chromium (Cr) or Ni—Cu. The plated layer  63  may be made of, for example, a metal such as tin (Sn). 
     The underlying layer  61  is formed by, for example, applying and baking a conductive paste. The plated layers  62  and  63  are formed by, for example, electroplating. 
       FIGS. 6A to 6C  illustrate exemplary steps for forming the underlying layer  61  of each terminal electrode  50 . 
     First, as illustrated in  FIG. 6A , the core  20  is attached to a holder  100 . The holder  100  includes a holding portion  102  that holds the core  20  with the axial direction of the core  20  inclined relative to a lower face  101  of the holder  100 . 
     The holder  100  is adhesive and elastic, and holds the core  20  in a removable manner. The holder  100  may be made of, for example, silicone rubber. 
     Conductive paste  120  is contained in a reservoir  110 . The conductive paste  120  is, for example, silver (Ag) paste. The bottom face  36  of one of the supports  22  of the core  20  is immersed in the conductive paste  120 . At this time, the core  20  is brought into contact with the reservoir  110  in such a manner that the holder  100  is not deformed. In this step, the conductive paste  120  adheres to the side faces  33  and  34  and the end face  32  of the support  22  so as to be connected to the conductive paste on the bottom face  36 . The conductive paste  120  adheres to the side faces  33  and  34  of the support  22  so that the height thereof from the bottom face  36  increases with increasing distance from the inner face  31  that opposes the inner face  31  of the other support  22  toward the end face  32 . 
     Next, as illustrated in  FIG. 6B , the holder  100  is pushed toward the reservoir  110 . The holder  100  is elastic, and therefore allows a change in position of the core  20  held by the holder  100 . The core  20  changes its position so as to change the inclination of the shaft  21  of the core  20 . In the present embodiment, the core  20  is caused to change its position so that the shaft  21  of the core  20  becomes more perpendicular to the surface of the conductive paste  120 . In this step, the conductive paste  120  adheres to the end face  32  of the support  22  so that the height thereof from the bottom face  36  of the support  22  is greater than that of the conductive paste  120  on the side faces  33  and  34 . The top edge of the conductive paste  120  on the end face  32  is substantially straight. 
     Next, as illustrated in  FIG. 6C , the core  20  is placed so that the bottom face  36  of the support  22  faces upward. The viscosity of the conductive paste  120  may be adjusted, for example, so that the conductive paste  120  on the end face  32  moves downward along the end face  32  from the position indicated by the two-dot chain line. The conductive paste  120  moves downward so that a central portion of a bottom edge  120   a  of the conductive paste  120  in the width direction Wd reaches a lowest position. The conductive paste  120  is dried in this state. The conductive paste  120  is also applied to the other support  22  in a similar manner, and is dried. Then, the conductive paste on the core  20  is baked to form the underlying layer  61  (electrode film) illustrated in  FIG. 5 . 
     Then, the plated layers  62  and  63  illustrated in  FIG. 5  are formed on the surface of the underlying layer  61  by, for example, electroplating. The terminal electrodes  50  are formed by the above-described steps. 
     As illustrated in  FIG. 5 , each terminal electrode  50  is formed so that the bottom electrode section  51  on the bottom face  36  of the support  22  and the end electrode section  52  on the end face  32  of the support  22  are connected to each other. The ridge  42  at the boundary between the bottom face  36  and the end face  32  of the support  22  is rounded. The radius of curvature of the ridge  42  is greater than or equal to about 20 μm (35 μm in the present embodiment). Such a ridge  42  facilitates formation of the terminal electrode  50  that continuously extends from the bottom face  36  of the support  22  to the end face  32  of the support  22 . 
     When the core has a ridge  42  whose radius of curvature is less than about 20 μm or when the core does not have a rounded ridge  42 , the thickness of the terminal electrode (underlying layer) on the ridge at the boundary between the bottom face and the end face is reduced, and the bottom electrode section and the end electrode section are easily disconnected. In contrast, when the radius of curvature of the ridge  42  is greater than or equal to about 20 μm, the terminal electrode  50  (underlying layer  61 ) has a sufficient thickness at the ridge  42 . Therefore, the bottom electrode section  51  and the end electrode section  52  are not easily disconnected. 
     The wire  70  is wound around the shaft  21 . The wire  70  includes, for example, a core having a substantially circular cross section and a cladding that covers the surface of the core. The core may be made of, for example, a material containing a conductive material, such as Cu and Ag, as a main component. The cladding may be made of, for example, an insulating material, such as polyurethane and polyester. Both end portions of the wire  70  are electrically connected to the respective terminal electrodes  50 . The wire  70  may be connected to the terminal electrodes  50  by, for example, soldering. More specifically, the plated layer  63  of each terminal electrode  50  may be formed of a Sn layer, and the wire  70  may be connected to the terminal electrode  50  by thermally bonding a portion of the wire  70  in which the cladding is removed and the core is exposed to the plated layer  63 . The connecting method is not limited to this, and various known methods may be used. 
     The diameter of the wire  70  is preferably in the range of, for example, about 14 μm to about 30 μm, and more preferably in the range of about 15 μm to about 28 μm. In the present embodiment, the diameter of the wire  70  is about 25 μm. When the diameter of the wire  70  is greater than a certain value, an increase in the resistance component can be suppressed. When the diameter of the wire  70  is less than a certain value, the wire  70  can be prevented from protruding from the core  20 . 
     As illustrated in  FIG. 1A , the wire  70  includes a wound portion  71  wound around the shaft  21 , connected portions  72  connected to the terminal electrodes  50 , and extending portions  73  that extend between the wound portion  71  and the connected portions  72 . The connected portions  72  are connected to the bottom electrode sections  51  of the terminal electrodes  50 , the bottom electrode sections  51  being formed on the bottom faces  36  of the supports  22 . 
     The wire  70  is wound around the shaft  21  with spaces provided between the wire  70  and the supports  22 . In other words, end portions  71   a  and  71   b  of the wound portion  71  are spaced from the supports  22  of the core  20 . The distance Lb from the end portions  71   a  and  71   b  of the wound portion  71  to the supports  22  is preferably less than or equal to about 5 times the diameter of the wire  70 , and more preferably less than or equal to about 4 times the diameter of the wire  70 . In the present embodiment, the distance Lb between the wire  70  and the supports  22  is less than or equal to about 3 times the diameter of the wire  70 . 
     The distance from the end portions  71   a  and  71   b  of the wound portion  71  to the supports  22  affects the length of the extending portions  73 . The extending portions  73  connect the wound portion  71  to the connected portions  72 , which are connected to the bottom electrode sections  51  of the terminal electrodes  50  formed on the supports  22 . Therefore, when the end portions  71   a  and  71   b  of the wound portion  71  are spaced from the supports  22  by a large distance, the extending portions  73  are long and are spaced from the supports  22  and the shaft  21  by a large distance. In such a case, there is a risk that the extending portions  73  will be damaged or the wire  70  will break. There is also a risk that the wire  70  will be loosened due to the extending portions  73 , protrude from the end portions of the supports  22 , and be damaged. These risks can be reduced by appropriately setting the distance from the end portions  71   a  and  71   b  of the wound portion  71  to the supports  22 . 
     As illustrated in  FIG. 2 , the inductor component  10  further includes a cover member  80 . In  FIGS. 1A and 1B , the cover member  80  is indicated by two-dot chain lines to provide better visibility of the core  20  and the wire  70 . 
     The cover member  80  is disposed at least between the supports  22  so as to cover the wire  70  at the side near the top faces  35 . More specifically, the cover member  80  extends from the top face  35  of one support  22  to the top face  35  of the other support  22  along the upper portion of the shaft  21 . The cover member  80  has a substantially flat top face  81 . The cover member  80  may be made of, for example, an epoxy resin. 
     In the present embodiment, the dimension of the cover member  80  in the length direction Ld in  FIG. 1A  (length dimension L 2 ) is smaller than the length dimension L 1  of the inductor component  10  including the terminal electrodes  50 . The dimension of the cover member  80  in the width direction Wd in  FIG. 1B  (width dimension W 2 ) is smaller than the width dimension W 1  of the inductor component  10  including the terminal electrodes  50 . In other words, in the present embodiment, the dimensions of a portion of the inductor component  10  around the top faces  35  of the core  20  (that is, the length dimension L 2  and width dimension W 2  of the cover member  80 ) are smaller than the dimensions of a portion of the inductor component  10  around the bottom faces  36  of the core  20  (the length dimension L 1  and width dimension W 1 ). 
     The cover member  80  enables reliable suction by a suction nozzle when, for example, the inductor component  10  is mounted on the circuit board. The cover member  80  also prevents the wire  70  from being damaged during suction by the suction nozzle. When the cover member  80  is made of a magnetic material, the inductance (L) of the inductor component  10  can be increased. When the cover member  80  is made of a non-magnetic material, magnetic loss can be reduced and the Q factor of the inductor component  10  can be increased. 
     Effects 
     The effects of the inductor component  10  due to the above-described structure thereof will now be described. 
     Each terminal electrode  50  of the inductor component  10  according to the present embodiment includes the bottom electrode section  51  on the bottom face  36  of the corresponding support  22 , the side electrode sections  53  on the side faces  33  and  34  of the support  22 , and the end electrode section  52  on the end face  32  of the support  22 . The end portions  52   b  of the end electrode section  52  adjacent to the side faces  33  and  34  are higher than the end portions of the side electrode sections  53  adjacent to the end face  32 . With this structure, the surface area of the terminal electrode  50  is increased. When the surface area is increased, the terminal electrode  50  can be strongly connected to the circuit board after the mounting process. In other words, the fixing force between the inductor component  10  and the circuit board can be increased. 
     The end electrode section  52  is higher at the central portion  52   a  than at the end portions  52   b  in the width direction Wd. Accordingly, the surface area of the end electrode section  52  is greater than that in the case where the central portion  52   a  and the end portions  52   b  have the same height. Thus, the terminal electrode  50  can be strongly connected to the circuit board. In other words, the fixing force between the inductor component  10  and the circuit board can be increased. Furthermore, the top edge  52   c  of the end electrode section  52  is substantially upwardly convex arc-shaped. When the top edge  52   c  is arc-shaped, the surface area of the terminal electrode  50  can be further increased. 
     When the inductor component  10  is soldered to pads formed on the circuit board, solder fillet extends along the central portion  52   a  of the end electrode section  52 . Since the end electrode section  52  of the inductor component  10  is higher at the central portion  52   a  than at the end portions  52   b , the height to which the solder extends can be increased. Thus, the inductor component  10  that is reduced in size can be sufficiently strongly fixed to the circuit board on which the inductor component  10  is to be mounted. The fixing force between the inductor component  10  and the circuit board may be, for example, greater than or equal to about 5.22 N. 
     In the present embodiment, the height dimension T 1  of the inductor component  10  is greater than the width dimension W 1  of the inductor component  10  (T 1 &gt;W 1 ). Therefore, the height of the end electrode section  52  can be increased relative to a certain mounting area, and the surface area of the end electrode section  52  can be further increased. 
     The terminal electrodes  50  according to the present embodiment are effective in achieving the inductance required of the inductor component  10 . More specifically, the magnetic flux generated in the shaft  21  of the core  20  by the wire  70  extends from the shaft  21  so as to pass through one support  22 , the air, and the other support  22 , and returns to the shaft  21 . In the inductor component  10  according to the present embodiment, the heights of the end portions  52   b  and the side electrode sections  53  connected to the end portions  52   b  are smaller than the height of the central portion  52   a . Therefore, each terminal electrode  50  does not block the magnetic flux at most parts of the side faces  33  and  34  of the corresponding support  22  and the ridges between the end face  32  and the side faces  33  and  34 , and causes less reduction in the total amount of magnetic flux. A reduction in the total amount of magnetic flux causes a reduction in the inductance, and therefore the desired inductance (inductance corresponding to the design of the core) cannot be obtained. According to the present embodiment, since the inductor component  10  causes less reduction in the total amount of magnetic flux, the inductance acquisition efficiency can be increased. For example, the inductance of the inductor component  10  may be greater than or equal to about 560 nH for an input signal having a frequency of about 10 MHz. In addition, since each terminal electrode  50  does not block the magnetic flux at most parts of the ridges as described above, the occurrence of eddy current loss in the terminal electrode  50  can be reduced. This leads to less reduction in the Q factor. 
     The terminal electrodes  50  include the side electrode sections  53  on the side faces  33  and  34  of the supports  22 . The heights of the side electrode sections  53  gradually increase with increasing distances from the inner faces  31  toward the end faces  32  of the supports  22 . In other words, the side electrode sections  53  are lower at the ends adjacent to the inner faces  31  than at the ends adjacent to the end faces  32 . Therefore, even when the heights of the end electrode sections  52  are increased, the risk of interference between the wire  70  and solder in the regions near the inner faces  31  can be reduced in the mounting process. 
     Since the height of each side electrode section  53  is large at the end adjacent to the end face  32 , the surface area of the side electrode section  53  is larger than that in the case where the side electrode section  53  has a constant height. Therefore, the fixing force between the inductor component  10  and the circuit board can be further increased. When the surface area of each side electrode section  53  is large, the thickness of the side electrode section  53  can be easily increased. Therefore, the width dimension W 1  of the inductor component  10  including the core  20  and the terminal electrodes  50  is greater than the width dimension of the core  20  and the width dimension W 2  of the cover member  80 . The inductor component  10  having such a structure is not easily inclined with respect to the width direction Wd in the mounting process. Thus, the inductor component  10  can be easily placed in a stable position in the mounting process. 
     The width dimension of the upper portion of the inductor component  10 , that is, the width dimension W 2  of the cover member  80 , is smaller than that of a mounting portion of the inductor component  10  (width dimension W 1 ). Therefore, the gap between the upper portion of the inductor component  10  and a component mounted adjacent to the inductor component  10  can be increased at the top side. Thus, even when the inductor component  10  is inclined with respect to the width direction Wd when the inductor component  10  is soldered, the risk of interference between the inductor component  10  and the component adjacent thereto can be reduced. 
     Similarly, in the inductor component  10 , since the height of each side electrode section  53  is large at the end adjacent to the end face  32 , the area of the end electrode section  52  on the end face  32  is also larger than that in the case where the side electrode section  53  has a constant height. Therefore, the thickness of the end electrode section  52  can also be easily increased. Thus, the length dimension L 1  of the inductor component  10  including the core  20  and the terminal electrodes  50  is greater than the length dimension of the core  20  and the length dimension L 2  of the cover member  80 . This also enables the inductor component  10  to be easily placed in a stable position in the mounting process. 
     When the thicknesses of the end electrode section  52  and the side electrode sections  53  are increased, the center of gravity of the inductor component  10  is lowered. This also enables the inductor component  10  to be easily placed in a stable position in the mounting process. 
       FIG. 7B  illustrates an inductor component including a core  90  according to a comparative example. In the comparative example, constituent members that are the same as those in the present embodiment are denoted by the same reference numerals to facilitate understanding of comparison between the comparative example and the present embodiment. In the core  90  of the comparative example, the ridges  41  adjacent to the inner faces  31  and the ridges  42  adjacent to the end faces  32  have the same radius of curvature (for example, 20 μm). In this case, the wire  70  is curved with a small radius of curvature at the ridges  41 , and force is concentrated at the curved portions. Therefore, when the diameter of the wire  70  is less than or equal to a certain value (for example, about 25 μm), there is a risk that the wire  70  will break. 
     In contrast, in the core  20  included in the inductor component  10  according to the present embodiment illustrated in  FIG. 7A , the radius of curvature of the ridges  41  adjacent to the inner faces  31  is greater than that of the ridges  42  adjacent to the end faces  32 , and is, for example, about 40 μm. Therefore, the wire  70  is curved with a large radius of curvature at the ridges  41 , and the concentration of force is reduced. Thus, breakage of the wire  70 , for example, does not easily occur. 
     In addition, the extending portions  73  that extend between the shaft  21  and the terminal electrodes  50  (portions that are in midair and not in contact with the core  20 ) are shorter than those in the comparative example illustrated in  FIG. 7B . When the extending portions  73  are long, there is a risk that the extending portions  73  will be damaged or the wire  70  will break. There is also a risk that the wire  70  will be loosened due to the extending portions  73 , protrude from the end portions of the supports  22 , and be damaged. In the present embodiment, these risks can be reduced because the extending portions  73  are shorter than those in the comparative example. 
     As described above, when the radius of curvature of the ridges  41  is greater than a certain value, the risk of breakage of the wire  70 , for example, can be reduced. However, when the radius of curvature of the ridges  41  is smaller than a certain value, the area of the bottom faces  36  of the supports  22  can be increased, so that the inductor component  10  can be stably mounted. 
     As described above, the present embodiment has the following effects. 
     (1-1) The inductor component  10  includes the core  20 , the pair of terminal electrodes  50 , and the wire  70 . The core  20  includes the shaft  21  and the pair of supports  22 . The shaft  21  is substantially rectangular parallelepiped shaped. The supports  22  are provided at both ends of the shaft  21 . The wire  70  is wound around the shaft  21 , and both end portions thereof are connected to the terminal electrodes  50  on the respective supports  22 . 
     Each terminal electrode  50  includes the bottom electrode section  51  on the bottom face  36  of the corresponding support  22 , the side electrode sections  53  on the side faces  33  and  34  of the support  22 , and the end electrode section  52  on the end face  32  of the support  22 . The end portions  52   b  of the end electrode section  52  adjacent to the side faces  33  and  34  are higher than the end portions of the side electrode sections  53  adjacent to the end face  32 . With this structure, the surface area of the terminal electrode  50  is increased. When the surface area is increased, the terminal electrode  50  can be strongly connected to the circuit board after the mounting process. In other words, the fixing force between the inductor component  10  and the circuit board can be increased. Accordingly, even when, for example, the inductor component  10  is reduced in size, the inductor component  10  can be sufficiently strongly fixed to the circuit board on which the inductor component  10  is to be mounted. 
     (1-2) The end electrode section  52  is higher at the central portion  52   a  than at the end portions  52   b  in the width direction Wd. Accordingly, the surface area of the end electrode section  52  is greater than that in the case where the central portion  52   a  and the end portions  52   b  have the same height. Thus, the terminal electrode  50  can be strongly connected to the circuit board. In other words, the fixing force between the inductor component  10  and the circuit board can be increased. Furthermore, the top edge  52   c  of the end electrode section  52  is substantially upwardly convex arc-shaped. Thus, the surface area of the end electrode section  52  can be further increased. In other words, the surface area of the terminal electrode  50  can be further increased. 
     (1-3) The height dimension T 1  of the inductor component  10  is greater than the width dimension W 1  of the inductor component  10  (T 1 &gt;W 1 ). Therefore, the height of the end electrode section  52  can be increased relative to a certain mounting area, and the surface area of the end electrode section  52  can be further increased. 
     (1-4) The magnetic flux generated in the shaft  21  of the core  20  by the wire  70  extends from the shaft  21  so as to pass through one support  22 , the air, and the other support  22 , and returns to the shaft  21 . In the inductor component  10  according to the present embodiment, the heights of the end portions  52   b  and the side electrode sections  53  connected to the end portions  52   b  are smaller than the height of the central portion  52   a . Therefore, each terminal electrode  50  does not block the magnetic flux at most parts of the side faces  33  and  34  of the corresponding support  22  and the ridges between the end face  32  and the side faces  33  and  34 , and causes less reduction in the total amount of magnetic flux. A reduction in the total amount of magnetic flux causes a reduction in the inductance, and therefore the desired inductance (inductance corresponding to the design of the core) cannot be obtained. According to the present embodiment, since the inductor component  10  causes less reduction in the total amount of magnetic flux, the inductance acquisition efficiency can be increased. In addition, since each terminal electrode  50  does not block the magnetic flux at most parts of the ridges of the support  22 , the occurrence of eddy current loss in the terminal electrode  50  can be reduced. This leads to less reduction in the Q factor. 
     (1-5) The heights of the side electrode sections  53  increase with increasing distances from the opposing inner faces  31  toward the end faces  32  of the supports  22 . Thus, the terminal electrodes  50  are lower at the inner faces  31  than at the end faces  32 . Therefore, even when the heights of the end electrode sections  52  are increased, the risk of interference between the wire  70  and solder in the regions near the inner faces  31  can be reduced in the mounting process. In addition, since the side electrode sections  53  are high at the ends adjacent to the end faces  32  and have a large surface area, the terminal electrodes  50  can be strongly connected to the circuit board. In other words, the fixing force between the inductor component  10  and the circuit board can be increased. 
     (1-6) Each support  22  includes the rounded ridge  41  at the boundary between the inner face  31  and the bottom face  36 , and the rounded ridge  42  at the boundary between the end face  32  and the bottom face  36 . The radius of curvature of the ridge  42  is greater than or equal to about 20 μm, and the radius of curvature of the ridge  41  is greater than the radius of curvature of the ridge  42 . The wire  70  is wound around the shaft  21 , and the connected portions  72  thereof are connected to the bottom electrode sections  51  of the terminal electrodes  50 . Thus, the wire  70  extends from the bottom face  36  of each support  22  to the shaft  21 . Since the ridge  41  of the support  22  at the boundary between the bottom face  36  and the inner face  31  has a large radius of curvature, the wire  70  is curved with a large radius of curvature at the ridge  41 . Thus, the occurrence of breakage of the wire  70  can be reduced. 
     (1-7) Each terminal electrode  50  includes the underlying layer  61  on the surface of the corresponding support  22  and the plated layers  62  and  63  on the surface of the underlying layer  61 . The maximum thickness of the underlying layer  61  on the end face  32  is greater than the maximum thickness of the underlying layer  61  on the bottom face  36 . With this structure, the adhesion between the underlying layer  61  on the end face  32  and the end face  32  can be increased, and the surface area of the end electrode section  52  can be further increased. Therefore, separation of the terminal electrode  50 , for example, can be reduced, and the fixing force between the inductor component  10  and the circuit board can be increased. The underlying layer  61  on the bottom face  36  receives load when the wire  70  is connected thereto, and the adhesion thereof is increased accordingly. Therefore, the underlying layer  61  is not easily separated even when the thickness thereof is relatively small. 
     Second Embodiment 
     A second embodiment will now be described. 
     In this embodiment, constituent members that are the same as those in the above-described embodiment are denoted by the same reference numerals, and description thereof may be partially or entirely omitted. 
     An inductor component  10   a  illustrated in  FIGS. 8A, 8B, and 9  includes the core  20 , the pair of terminal electrodes  50 , and a wire  70   a . The wire  70   a  is wound around the shaft  21  so as to form a single layer on the shaft  21 . Both end portions of the wire  70   a  are connected to the respective terminal electrodes  50 . The inductor component  10   a  is a wire-wound inductor component. 
     As illustrated in  FIG. 8A , the wire  70   a  includes a wound portion  71  wound around the shaft  21 , connected portions  72  connected to the terminal electrodes  50 , and extending portions  73  that extend between the wound portion  71  and the connected portions  72 . The connected portions  72  are connected to the bottom electrode sections  51  of the terminal electrodes  50 , the bottom electrode sections  51  being formed on the bottom faces  36  of the supports  22 . 
     The wound portion  71  includes at least one section in which the distance between adjacent turns in the length direction Ld (single turn is a part of the wound portion  71  that extends around the shaft  21  once) is greater than or equal to a predetermined value. The predetermined value is, for example, preferably greater than or equal to about 0.5 times the diameter of the wire  70   a , and more preferably greater than or equal to about 1 times the diameter of the wire  70   a . In the present embodiment, the distance La between the turns indicated by an arrow in  FIG. 8A  is greater than or equal to about 2 times the diameter of the wire  70   a . Thus, the wound portion  71  of the present embodiment includes at least one section in which the distance between the adjacent turns of the wire  70   a  is greater than or equal to about 2 times the diameter of the wire  70   a.    
     A parasitic capacitance is generated between the adjacent turns of the wound portion  71  in the axial direction of the shaft  21 . The value of the parasitic capacitance is determined by the distance between the adjacent turns. As the distance between the adjacent turns increases, the value of the parasitic capacitance decreases. In other words, the influence of the parasitic capacitance can be reduced, which leads to a less reduction in the self-resonance frequency (SRF). Thus, the inductor component  10   a  according to the present embodiment may have an SRF of greater than or equal to about 3.6 GHz. 
     For example, the inductor component  10   a  has electrical characteristics such that the impedance thereof is greater than or equal to about 500Ω for an input signal having a frequency of about 3.6 GHz. The impedance of the inductor component  10   a , which is determined based on the frequency of the input signal, is preferably greater than or equal to about 300Ω at a frequency of about 1.0 GHz and greater than or equal to about 400Ω at a frequency of about 1.5 GHz, more preferably greater than or equal to about 450 S at a frequency of about 2.0 GHz, and still more preferably greater than or equal to about 500Ω at a frequency of about 4.0 GHz. When the impedance is greater than or equal to a certain value at a specific frequency, noise reduction (choke), resonance (bandpass), and impedance matching can be realized at that frequency. 
     The inductance of the inductor component  10   a  is preferably about 40 nH to about 70 nH. When the inductance is greater than or equal to about 40 nH, an impedance of greater than or equal to a certain value can be obtained. When the inductance is less than or equal to about 70 nH, a high SRF can be obtained. In the present embodiment, the inductance of the inductor component  10   a  is, for example, about 60 nH. The above-mentioned inductances are based on an input signal having a frequency of about 10 MHz. 
     The SRF of the inductor component  10   a  is preferably greater than or equal to about 3.0 GHz, more preferably greater than or equal to about 3.2 GHz, and still more preferably greater than or equal to about 3.4 GHz. Thus, the function of the inductor component can be obtained in a high-frequency band. 
     The operation of the above-described inductor component  10   a  will now be described. 
       FIG. 10  is a graph showing the frequency-impedance characteristics. In  FIG. 10 , the solid line represents the characteristics of the inductor component  10   a  according to the present embodiment, and the one-dot chain line represents the characteristics of an inductor component according to a comparative example. 
     The inductor component according to the comparative example includes a core having the same size and shape as the core  20  of the inductor component  10   a  according to the present embodiment, and a wire having the same thickness as the wire  70   a  of the present embodiment, the wire being densely wound around the core. In other words, the wire of the inductor component according to the comparative example includes a wound portion that is wound around the shaft of the core so that adjacent turns are close to each other in the length direction Ld. The inductor component according to the comparative example has an inductance of, for example, about 560 nH, and an SRF of less than or equal to about 1.5 GHz. 
     In general, an inductor component functions mainly as a capacitive element at a frequency higher than the SRF. Therefore, as illustrated in  FIG. 10 , the impedance of the inductor component according to the comparative example decreases in a range in which the frequency is greater than or equal to about 1.5 GHz. 
     In contrast, the impedance of the inductor component  10   a  according to the present embodiment is greater than or equal to about 400Ω for an input signal having a frequency of greater than or equal to about 1.5 GHz. The impedance is greater than or equal to about 500Ω when the frequency is greater than or equal to about 2.0 GHz. This is because the SRF of the inductor component  10   a  according to the present embodiment is greater than or equal to about 3.6 GHz. 
     As described above, the present embodiment has the following effects in addition to the effects of the above-described first embodiment. 
     (2-1) The inductor component  10   a  includes the core  20 , the pair of terminal electrodes  50 , and the wire  70   a.    
     The wire  70   a  is wound around the shaft  21  so as to form a single layer on the shaft  21 . Both end portions of the wire  70   a  are connected to the respective terminal electrodes  50 . The wire  70   a  includes the wound portion  71  wound around the shaft  21 , the connected portions  72  connected to the terminal electrodes  50 , and the extending portions  73  that extend between the wound portion  71  and the connected portions  72 . The connected portions  72  are connected to the bottom electrode sections  51  of the terminal electrodes  50 , the bottom electrode sections  51  being formed on the bottom faces  36  of the supports  22 . The wound portion  71  includes at least one section in which the distance between adjacent turns in the length direction Ld (single turn is a part of the wound portion  71  that extends around the shaft  21  once) is greater than or equal to a predetermined value. The inductor component  10   a  has electrical characteristics such that the impedance thereof is greater than or equal to about 500Ω for an input signal having a frequency of about 3.6 GHz. Thus, the inductor component  10   a  having a desired function in a high-frequency range can be provided. 
     Modifications 
     Each of the above-described embodiments may be implemented in the following manner. 
     In each of the above-described embodiments, the shape of the terminal electrodes may be changed as appropriate. 
     Although the top edge of each side electrode section  53  is substantially straight in each of the above-described embodiments, the top edge may have another shape. 
     Side electrode sections  53   a  illustrated in  FIG. 11  each include two portions having different inclinations. Among the two portions, the portion adjacent to the end face  32  has an inclination greater than that of the portion adjacent to the inner face  31 . 
     Side electrode sections  53   b  illustrated in  FIG. 12  each include two portions having different inclinations. Among the two portions, the portion adjacent to the inner face  31  has an inclination greater than that of the portion adjacent to the end face  32 . The side electrode sections  53   a  and  53   b  increase the design flexibility of the terminal electrodes of the inductor component and the land pattern on the circuit board. 
     Side electrode sections  53   c  illustrated in  FIG. 13  each include two portions having different inclinations similar to those of each side electrode section  53   b . In addition, each terminal electrode  50  includes a ridge electrode section  54  disposed between the side electrode section  53   c  and the end electrode section  52  on the ridge at the boundary between the side face  33  and the end face  32 . The ridge electrode section  54  has an inclination greater than that of the side electrode section  53   c . In this structure, the end electrode section  52  can be formed so that the surface area thereof is larger than that in the structure without the ridge electrode section  54 . 
     In the above-described embodiments, the terminal electrodes  50  on the supports  22  (first support and second support) provided at the respective end portions of the shaft  21  have the same shape. However, the terminal electrode  50  on the first support and the terminal electrode  50  on the second support may have different shapes. In addition, although the side electrode sections  53  are shaped so that the heights thereof gradually increase with increasing distances from the inner faces  31  of the supports  22  toward the end faces  32  of the supports  22 , the shapes of the side electrode sections are not limited to this, and may instead be such that the heights thereof are partially reduced. Furthermore, the number of portions of each side electrode section having different inclinations is not limited to two, and may instead be three or more. Also, each side electrode section may further include a curved portion in a region outside the inclined portions. The side electrode sections on both sides of each support may include top edges having different shapes. In addition, the side electrode sections on one of the supports and the side electrode sections on the other support may have different inclination angles. 
     Referring to  FIG. 14 , the terminal electrode  50  on the first support (support  22  on the right side in  FIG. 14 ) among the pair of supports  22  is formed such that, as in the above-described embodiment, the end portion  52   b  (see  FIG. 1B ) of the end electrode section  52  adjacent to the side face  33  is higher than the end portion of the side electrode section  53  adjacent to the end face  32 . In this case, for example, a terminal electrode  50   a  on the second support (support  22  on the left side in  FIG. 14 ) among the pair of supports  22  may be formed such that the height of an end portion of an end electrode section  55  adjacent to the side face  33  is substantially equal to that of the end portion of the side electrode section  53  adjacent to the end face  32 . 
     In the first embodiment, the shape of the cover member  80  may be changed as appropriate. 
     An inductor component  10   b  illustrated in  FIG. 15  includes a cover member  80   b  that does not cover the top faces  35  of the supports  22  but covers an upper face of the shaft  21 . More specifically, the cover member  80   b  is formed so as to cover the wire  70  (wound portion  71 ) wound around the shaft  21 . The cover member  80   b  has a substantially flat top face  81 . The top faces  35  of the supports  22  are exposed. In this structure, the length and width dimensions of the inductor component  10   b  at the top side are substantially equal to the length and width dimensions of the core  20 . 
     The cover member may instead be formed so as to cover only portions of the wire  70  that are between the supports  22  and around an upper portion of the shaft  21 . Alternatively, the cover member may be formed so as to cover only portions of the wire  70  on the upper face and both side faces of the shaft  21 . Alternatively, the cover member may be formed so as to cover the entirety of the wound portion  71  of the wire  70 . The cover member  80  may be omitted. This also applies to the second embodiment. 
     In each of the above-described embodiments, the shape of the core  20  may be changed as appropriate. 
       FIG. 16  illustrates a core  200  including a substantially rectangular-parallelepiped-shaped shaft  201  and supports  202  provided at respective end portions of the shaft  201 . Each support  202  has the same width as the shaft  201 , and extends upward and downward from the shaft  201 . Thus, the core  200  has H-shaped side faces. The core  200  illustrated in  FIG. 16  is an example, and the shapes of the shaft  201  and the supports  202  may be changed as appropriate. 
     In the above-described second embodiment, the inductor component having an impedance of greater than or equal to about 500Ω for an input signal having a frequency of about 3.6 GHz is not limited to that having the structures of the above-described inductor component  10   a  according to the embodiment. The above-described characteristics may also be obtained by changing, selecting, or combining the structures as appropriate. 
     In the above-described embodiments, the elastic holder  100  is used to form the underlying layer  61  of each terminal electrode  50  on the core  20  by changing the angle of the core  20 . However, the underlying layer may instead be formed on the core in multiple steps. For example, the underlying layer  61  of each terminal electrode  50  may be formed on the core by dipping the core in the conductive paste  120  by using two holders having different inclinations. 
     In each of the above-described embodiments, the height dimension T 1  of the inductor component  10  is greater than the width dimension W 1  of the inductor component  10 . However, the width dimension W 1  and the height dimension T 1  of the inductor component may instead be equal. 
     The structures of the above-described embodiments and modifications may be changed, selected, or combined as appropriate. The structure of a part of the embodiments or modifications may be combined with the structure of another part. 
     While some embodiments of the disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the disclosure.