JP2019041082A - coil - Google Patents

Abstract

To provide a surface mount coil which can be mounted on a circuit board with high reliability such as vibration resistance.SOLUTION: The coil includes: a hollow cylindrical core; and an outer case housing the entire core. The core and the outer case are bonded and fixed at least at each of an upper corner and a lower corner in a viewing field from a direction in which a hollow portion of the core is disposed laterally in the lateral direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coil that can be easily and reliably mounted on a circuit board.

  The reliability required for surface mount electronic components directly attached to circuit boards has been increasing in recent years. For example, it is extremely high for coils mounted on electronic circuit boards for automotive applications. Vibration resistance (impact resistance) and the like are required. The following Patent Document 1 includes a columnar electronic component and a rectangular parallelepiped case having a cylindrical through hole, and the lead wires led out from both ends of the case enter grooves in the lower part of the case, and are in the same plane. An invention in which the electrode part is formed by bending so as to become is disclosed.

  Further, it is described that the resistor does not fall from the case with such a configuration, so that it is possible to reduce the weight without using a filler. Further, it is described that since the electronic component main body is inserted into the case, the case dimension can be reduced to a length shorter than the main body. Further, since the bending position of the lead wire can be defined by the case dimensions, it is described in Patent Document 1 that it is possible to suppress the variation in the bending position and to improve the dimensional accuracy of the electrode part. .

  Patent Document 2 below discloses a small chip inductor that can be easily surface mounted. According to this document, the core groove accommodates and holds the end of the ribbon-like conductor, and the side wall of the groove functions as a standoff for stably mounting the inductor, which is advantageous in terms of downsizing and ease of surface mounting. It is described.

  Furthermore, the following Patent Document 3 is an invention aiming to provide a case storage type magnetic core that has high reliability as a magnetic component and generates less noise, and the case storage type magnetic core includes: The magnetic core is a case storage type magnetic core that is fixed to the case in which the magnetic core is stored using an adhesive. The magnetic core mass, the Young's modulus after curing of the adhesive, and the adhesive provided in the gap between the core end face and the case. A technical idea is disclosed in which the total thickness of the agent and the total adhesion area between the magnetic core end face and the case by the adhesive are formed so as to satisfy a predetermined relationship.

Japanese Patent Laid-Open No. 08-088103 Japanese Utility Model Publication No. 04-123513 JP 09-066943 A

  However, in recent years, surface mount coils, including electronic components mounted on circuit boards for in-vehicle applications, have been required to have higher reliability such as further vibration resistance and impact resistance.

  The present invention has been made in view of the above-mentioned problems, and an object thereof is to provide a surface mount coil that has high reliability such as vibration resistance and impact resistance and can be easily mounted on a circuit board. And

  The coil of the present invention is a coil including a hollow cylindrical core and an exterior case that houses the entire core, and the core and the exterior case are transparent from the direction in which the hollow portion is disposed in the lateral direction. In the field of view, at least one upper corner and one lower corner are bonded and fixed, respectively.

  A coil that can be mounted on a circuit board with high reliability such as vibration resistance can be provided.

It is a figure explaining the outline | summary of the surface mount coil of this embodiment, and its manufacturing method. It is a figure explaining the test result of an impact resistance test (destructive test) in the case of changing the application pattern of the adhesive (adhesive) by three types. It is a figure explaining the influence confirmation experiment to the electrical property of the amorphous core with respect to a sticking agent application area. It is a figure explaining the result of having measured the change of the electrical property by changing the application area of a fixing agent. It is a figure explaining the structure which prevents the bending of a lead wire for the further improvement of an impact-resistant characteristic. It is a perspective view explaining the external appearance of the surface mount coil of this embodiment. It is a perspective view explaining the external appearance of the bottom face side of the surface mount coil of this embodiment. It is a figure explaining the internal structure which removed the exterior case of the surface mount coil.

  The surface mount coil described in the present embodiment preferably has a hollow cylindrical amorphous core and its outer case, with respect to the hollow portion in a perspective view from the direction in which the hollow portion of the amorphous core is disposed in the lateral direction. Thus, two corners located vertically are more preferably bonded to each other at two oblique corners located diagonally to the hollow portion. In other words, with respect to the horizontal cylinder-shaped amorphous core, it is preferable to include at least two locations of the uppermost corner and the lowermost corner, and more preferably the periphery of the two locations so that the bonding area does not become too large. In addition, it shall be adhered and fixed to the exterior case. The amorphous core is shown as a typical example of the core, and is not limited to the amorphous core in the application of the present invention.

  In addition, since the “corner” is adhesively fixed, the uppermost corner and the vicinity of the upper end of the vertical side wall that continues to the uppermost corner are fixed. It shall be fixed with adhesive. By adopting such a configuration, a surface mount coil component having extremely high vibration resistance and impact resistance can be obtained without adversely affecting the inductance characteristics. Thereby, it becomes applicable also to the use as which high reliability is calculated | required, for example, for vehicle-mounted.

  Further, the surface mount coil described in the present embodiment is more preferably the case where the lead wire on the bottom surface bent and extended from the side surface to the bottom surface of the outer case is soldered to the footprint of the circuit board. It is soldered integrally with a pair of auxiliary terminals arranged on the bottom surface of the exterior case adjacent to both sides of the end. Further, the auxiliary terminal may be provided by insert molding and is fixed to the exterior case.

  For this reason, compared with the case where only the lead wire is soldered, the area of soldering can be increased, so that it is possible to more strongly mount with increased shock resistance and vibration resistance. . Therefore, embodiments will be described in detail below based on the drawings.

  FIG. 1 is a diagram for explaining the outline of the surface mount coil according to the present embodiment and the manufacturing method thereof. As shown in FIG. 1, first, a lead wire 1200 made of a flat-plated copper wire is cut to a predetermined length (a), and the cut lead wire 1200 is manually inserted into the hollow portion of the cylindrical amorphous core 1800. (B). Then, in (c), the amorphous core 1800 is disposed in the exterior case 1100 in which the adhesives 1810 (1) and 1810 (2) are previously applied to the corners thereof, and the exterior case 1100 is attached to the adhesive 1810 ( 1) and 1810 (2) are engaged so as to be in a diagonal position (d). Finally, the lead wire 1200 is bent along the outer case 1100 (e). Such manufacturing / assembling work can be performed manually, or part of the manufacturing / assembling work can be performed manually and other work can be performed as an automatic process by a mechanical process.

  FIG. 2 is a diagram for explaining the test results of an impact resistance test (destructive test) when the coating pattern is changed in three types when the same kind of fixing agent (adhesive) is used. By changing the application position and application amount of the fixing agent, the fracture resistance due to the difference between the adhesion position and the adhesion area was measured by the tensile strength using a measuring instrument “RZ-100 / AIKOH (FS: 1 kN)”. The shape is maintained when a 1.6mm copper wire is passed through the hollow part of the core through a small hole (φ2mm) on the side of the outer case and the lower part of the outer case is fixed in a vise and the wire is pulled upward. It is a measurement of the limit strength to be performed.

  As can be understood from FIG. 2, when the application amount is the same in the side perspective view in which the hollow portion of the transparent amorphous core is observed in the left-right direction, FIG. 2 (b) and FIG. 2 (c) applied so as to include the upper and lower corners of the amorphous core have a higher breaking strength and higher impact resistance than the coating pattern shown in FIG. I understand that. Therefore, it is preferable to apply the adhesive to the outer case and the amorphous core so as to include the upper and lower corner angles, and it is more preferable to apply the adhesive so as to include the upper and lower corner angles. In other words, it is preferable to apply the fixing agent to an end line that is line-symmetric with respect to a virtual line that connects the openings of the hollow part of the hollow cylindrical amorphous core or point-symmetric with respect to the center point of the virtual line. .

FIG. 3 is a diagram for explaining an experiment for confirming the influence of the adhesive agent application area on the amorphous core 1800 on the electrical characteristics of the amorphous core 1800. As shown in FIG. 3 (a), the adhesive agent is applied to the four corners in various states in a state where the hollow portion of the amorphous core 1800 inserted into the outer case 1100 is observed in the horizontal direction in the perspective view. A lead wire 1200 was inserted into the hollow portion of the amorphous core 1800, and a current of 30 A was passed, and the change in inductance was measured. In addition, as shown in FIG. 3 (b), the adhesive area in the case of 7 mg per site with the smallest coating amount and 4 mg of the adhesive at a total of 28 mg is about 90 mm ² , and the maximum is 40 mg per site, 4 sites. In the case of a total of 160 mg of the adhesive, the adhesion area was about 270 mm ² , and the measurement was performed by changing the application area (application amount) for a total of five patterns including the adhesive area. For comparison, the electrical characteristics when no sticking agent was used were also measured.

FIG. 4 is a diagram for explaining the result of measuring the inductance by applying a fixing agent by changing the application area of the fixing agent, passing a current of 30 A before and after curing. The degree of decrease in inductance measured after curing of the adhesive is shown based on the inductance measured before curing of the adhesive in each application area of the adhesive. In FIG. 4, (1) to (5) and “none” correspond to the conditions (1) to (6) shown in the table of FIG. 3 (b), respectively. From FIG. 4, when no sticking agent is used, the application area is 90 mm ² (application amount 7 mg / location), 110 mm ² (application amount 10 mg / location), 130 mm ² (application amount 13 mg / location), 180 mm ² (application amount). In the case of 25 mg / location), the rate of change in inductance before and after curing of the fixing agent can be suppressed to within 5%, but when the application area is 270 mm ² (application amount 40 mg / location), before and after curing of the fixing agent. It can be understood that the rate of change in inductance exceeds 10%. That is, it can be understood that the application area is preferably 180 mm ² (application amount 25 mg / location) or less in order to suppress the rate of decrease in inductance before and after the fixing agent is cured.

If the amount of the sticking agent applied increases, the surface area of the sticking agent adhering to the core increases, thereby increasing the stress applied to the amorphous core and presuming that the electrical characteristics such as inductance are affected. In addition, since the amorphous core shown in FIGS. 3 and 4 uses a core having a surface area of 300 cm ² (excluding the hollow portion), the ratio of the adhesive application area to the total surface area of the core is suppressed to 60% or less. As a result, it is possible to keep the variation in inductance within a range that does not substantially adversely affect the electrical characteristics. As described above, considering the impact resistance, it is preferable that the coating amount is large. On the other hand, considering the electrical characteristics, it is preferable to limit the coating amount. It is preferable to adjust the coating amount so that the ratio of the application area of the fixing agent to the total surface area of the core is 60% or less. As a result, it is possible to realize a surface mount coil having both good impact resistance and good inductance characteristics.

  FIG. 5 is a diagram illustrating a structure for preventing the lead wire 1200 from bending in order to further improve the impact resistance characteristics of the surface mount coil of the present embodiment. FIG. 5A shows a state in which the hollow portion of the amorphous core 1800 is arranged in the horizontal direction in the perspective view, and the reinforcing portion 1250 of the lead wire 1200 is only inside the outer case 1100, typically the core hollow portion. It is explained that the reinforcing portion 1250 described in FIGS. 5B and 5C is formed between the outer wall of the core hollow portion and the inner wall of the outer case 1100 having a clearance of about 0.5 mm. . In addition, 1810 (1) and 1810 (2) shown to Fig.5 (a) typically show the typical application | coating location of fixing agent.

  The reinforcing portion 1250 in FIG. 5B is an example of a reinforcing means for preventing bending formed in the lead wire 1200, and is formed in a concave shape in a cross-sectional view in the short width direction. In the present embodiment, the reinforcing portion 1250 is configured by forming a concave portion (a convex portion when viewed from the back side) extending in the length direction at the center of a flat-plated copper wire (lead wire 1200). With such a configuration, it is difficult to bend the portion where the reinforcing portion 1250 is formed, and when the lead wire 1200 is bent along the outer case 1100, the lead wire 1200 positioned in the outer case 1100 is inside the outer case 1100. Then, it becomes impossible to bend substantially.

  When the lead wire 1200 is bent on the bottom surface of the outer case 1100 along the outer surface of the outer case 1100 so as to be connected to the circuit board, in the case of a flat-plated copper wire without the reinforcing portion 1250, the lead wire 1200 is amorphous. The portion disposed in the hollow portion of the core is slightly bent so as to swell and easily bend. Even if it is curved, there is no influence on the electrical characteristics, but it has a shape that is slightly swollen outward not only inside the exterior case 1100 but also on the case side. As a result, unexpected stress such as floating is also applied to the lead wire 1200 arranged on the bottom surface side which is the mounting surface of the surface mount coil on the substrate, and there is a concern that it may adversely affect the reliability of the coil mounting. .

  On the other hand, by providing the reinforcing portion 1250 described with reference to FIG. 5, there is no bending inside the outer case 1100, and further, bending on the side surface and bottom surface of the outer case 1100 can be prevented. The shape of the reinforcing portion 1250 is not limited to that illustrated in FIG. 5, and is a known shape such as a concave portion or a convex portion having a function of preventing the lead wire from being bent, and fits inside the core hollow portion. Any shape and configuration can be adopted and applied. Further, the reinforcing portion 1250 can be provided in a part or all of the portion of the lead wire 1200 that is housed in the exterior case 1100. Next, an overall configuration outline of the surface mount coil of the present embodiment will be described.

  FIG. 6 is a perspective view for explaining the external appearance of the surface mount coil 1000 of the present embodiment. The surface mount coil 1000 includes an outer case 1100 formed of epoxy resin or the like. The outer case 1100 includes an upper outer case 1110 and a lower outer case 1120. A recess (not shown) that matches the shape of the stored amorphous core is formed inside the outer case 1100.

  As a result, the stored amorphous core fits into the inner wall of the recess in the outer case 1100, and the stored amorphous core is prevented from swinging inside. A support member (support member or guide member) that fixes and supports the amorphous core so as not to swing inside the case may be provided together with the recess or instead of the shape matching recess.

  Further, in FIG. 6, the lead wire 1200 (1) exposed to the outside from the side surface of the outer case 1100 is bent along the side surface of the outer case 1100 and extended downward, and is again brought to the bottom surface at the bottom surface of the outer case 1100. The bottom surface portion is soldered to a circuit board footprint (pad) or the like. As shown in FIG. 6, a pair of auxiliary terminals 1300 and 1400 arranged to sandwich the lead wire 1200 (1) are provided on the bottom surface of the lower exterior case 1120 by insert molding or the like. In the example of FIG. 6, the auxiliary terminals 1300 and 1400 are not electrically connected to the lead wire 1200 (1) and are fixed to the lower exterior case 1120.

  FIG. 7 is a perspective view for explaining the external appearance of the bottom surface side of the surface mount coil 1000 of the present embodiment. As can be understood from FIG. 7, the lead wire 1200 (1) is exposed from one side surface facing the one side surface of the outer case 1100, and extends to the bottom surface along the side surface of the outer case 1100.

  Further, the length of the lead wire 1200 (1) on the bottom surface is equal to the length of the auxiliary terminals 1300 and 1400. Further, when soldered and mounted on a circuit board, the lead wire 1200 (1) and the auxiliary terminals 1300 and 1400 can be integrally soldered to one footprint. For this reason, it is preferable that the lead wire 1200 (1) and the auxiliary terminals 1300 and 1400 have the same protruding height on the bottom surface, and more preferably the entire bottom surface is flush.

  Furthermore, as shown in FIG. 7, the lead wire 1200 (2) on the opposite end side of the lead wire 1200 (1) can be similarly soldered to one footprint integrally with the auxiliary terminals 1500 and 1600. . As a result, the soldered area and the amount of solder to be used are increased compared to the case of only the lead wire 1200 (hereinafter, the lead wire 1200 (1) and the lead wire 1200 (2) are collectively referred to as the lead wire 1200 as appropriate). In addition, the soldering strength is increased, and the reliability such as impact resistance can be increased. In addition, as compared with the case where only the lead wire 1200 is connected to the circuit board of the surface mount coil 1000, the auxiliary terminals 1500 and 1600 are provided, so that the fixing strength of the surface mount coil 1000 is secured by the auxiliary terminals 1500 and 1600. Therefore, when the circuit board vibrates, the load and influence on the lead wire 1200 responsible for electrical connection can be reduced, and the electrical connection can be further stabilized.

  6 and 7, the auxiliary terminals 1300, 1400, 1500, and 1600 may be electrically independent of each other and are not connected to each other. It can be assumed that 1200 is not electrically connected.

  When the circuit board is soldered, the lead wire 1200 (1) and the auxiliary terminals 1300 and 1400 observed on the front side of FIG. 7 are electrically connected to each other through the solder. The lead wire 1200 (2) and the auxiliary terminals 1500 and 1600 on the opposite end side observed on the back side in FIG. 7 are electrically connected to each other through solder.

  Further, the auxiliary terminal 1300 and the like may be formed of a plated copper wire material, and the lead wire 1200 may be formed of a flat-plated copper wire. In the surface mount coil 1000, the lead wire 1200 is firmly fixed to the circuit board by soldering, and the auxiliary terminals 1300, 1400, 1500, 1600 are firmly fixed to the circuit board by soldering. As a result, the outer case 1100 is firmly fixed to the circuit board via the auxiliary terminal 1300 and the like, so that the fixing strength is sufficiently high.

  FIG. 8 is a view for explaining the internal configuration of the surface mount coil 1000 with the outer case 1100 removed. 8A illustrates an internal state in which the upper outer case 1110 and the lower outer case 1120 are both removed, and FIG. 8B illustrates an internal state in which the upper outer case 1110 is removed. FIG. Illustrates the internal state with the lower outer case 1120 removed.

  In FIG. 8A, an amorphous core 1800 has a hollow cylindrical shape, and a lead wire 1200 is inserted through the hollow portion. That is, the lead wire 1200 (1) and the lead wire 1200 (2) described above correspond to the exposed end portions of one lead wire 1200 formed by bending with a flat-plated copper wire or the like. The amorphous core 1800 is a magnetic core formed by winding a ribbon ribbon of an amorphous magnetic alloy, which is a high magnetic material, and sintering. Further, in FIG. 8B, a recess that fits the shape of the amorphous core 1800 is formed inside the lower exterior case 1120 to prevent the amorphous core 1800 from swinging in the lower exterior case 1120. Yes.

  Similarly, in FIG. 8C, a recess that fits the shape of the amorphous core 1800 is formed inside the upper exterior case 1110 to prevent the amorphous core 1800 from swinging in the upper exterior case 1110. ing. The upper outer case 1110 and the lower outer case 1120 can be firmly fitted and fixed to each other using, for example, an adhesive.

  8B and 8C, a fixing member 1810 such as an adhesive can be applied to a predetermined portion of the amorphous core 1800, and the upper outer case 1110, the lower outer case 1120, and the amorphous core can be applied. 1800 can be more firmly fixed to each other by the fixing member 1810.

  The coil and the surface mount coil of the present invention are not limited to the configuration, the method of use, and the manufacturing method described in the above-described embodiments, and are appropriately within the scope obvious to those skilled in the art and within the technical idea of the present invention. Its configuration, usage and manufacturing method can be changed.

  The present invention is suitable for various on-vehicle electronic components, surface mount coils, and electronic components mounted on a circuit board that requires vibration resistance and impact resistance.

  1000 .... Surface mount coil, 1100 ... Exterior case, 11.10 ... Upper exterior case, 1120 ... Lower exterior case, 1200 ... Lead wire, 1300 ... Auxiliary terminal, 1400 ... Auxiliary terminal, 1500 ... Auxiliary terminal. 1600..Auxiliary terminal, 1800..Amorphous core, 1810..Fixing member.

Claims (5)

A hollow cylindrical core,
An outer case that houses the entire core, and a coil comprising:
The core and the outer case are
A coil, wherein the core is bonded and fixed at least at each of an upper corner angle and a lower corner angle in a perspective view from a direction in which the hollow portion of the core is arranged in the horizontal direction. The coil according to claim 1, wherein
The outer case is composed of a lower outer case that includes a bottom surface and stores a substantially lower half of the core, and an upper outer case that is fitted to the lower outer case and stores a substantially upper half of the core.
The core and the lower outer case are bonded and fixed at a first location including the lower left corner or the lower right corner of the core in a perspective view from the direction in which the hollow portion is disposed in the lateral direction.
The core and the upper exterior case include a second upper-right corner or an upper-left corner of the core that obliquely opposes the first location in a perspective view from the direction in which the hollow portion is disposed in the lateral direction. Coil that is bonded and fixed in place. The coil according to claim 1 or 2,
The coil bonded and fixed area is 60% or less of the total surface area excluding the inside of the hollow portion of the core. In the coil according to any one of claims 1 to 3,
In the hollow portion of the core, provided with a lead wire penetrated,
The lead wire led out from the side surface of the outer case is exposed by being bent along the outer surface of the outer case from the side surface to the bottom surface of the outer case,
Reinforcing means for preventing bending is formed in at least a part of a portion of the lead wire that is penetrated by the hollow portion. In the coil according to any one of claims 1 to 4,
The coil is a core formed by winding a belt-shaped magnetic alloy ribbon and sintering.