JP7027731B2 - coil - Google Patents

Description

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

The reliability required for surface-mounted electronic components that are directly mounted on circuit boards has been increasing in recent years, and is extremely high for coils that are surface-mounted on electronic circuit boards for in-vehicle use, for example. Vibration resistance (impact resistance) and the like are required. The following Patent Document 1 includes a cylindrical electronic component and a rectangular parallelepiped case having a cylindrical through hole, and the lead wires drawn from both ends of the case enter the groove at the lower part of the case and have the same plane. There is disclosed an invention in which an electrode portion is formed by bending so as to be.

Further, it is described that such a configuration does not require a filler and can be made lightweight because the resistor does not fall from the case. Further, it is described that the case size can be made smaller than the main body because the electronic component main body is inserted into the case. Further, it is described in Patent Document 1 that since the bending position of the lead wire can be defined by the case size, it is possible to suppress the variation in the bending position to a small extent and to improve the dimensional accuracy of the electrode portion. ..

Further, Patent Document 2 below discloses an invention of a chip inductor that is compact and easy to mount on a surface. According to this document, the groove of the core accommodates and holds the end of the ribbon-shaped conductor, and the side wall of the groove functions as a standoff for stably mounting the inductor, which is advantageous in terms of miniaturization and ease of surface mounting. It is stated that.

Further, the following Patent Document 3 is an invention for the purpose of providing a case-storing type magnetic core having high reliability as a magnetic component and generating less noise, and the case-storing type magnetic core is described. The magnetic core is a case-storage type magnetic core fixed to the case in which the magnetic core is stored by using an adhesive, and the mass of the magnetic core, the Young's ratio after curing of the adhesive, and the adhesion provided in the gap between the end face of the magnetic core and the case. A technical idea is disclosed so that the total thickness of the agent and the total adhesive area between the magnetic core end face and the case due to the adhesive are formed so as to satisfy a predetermined relationship.

Japanese Unexamined Patent Publication No. 08-088103 Jikkenhei 04-1235113 Gazette Japanese Unexamined Patent Publication No. 09-069443

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

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a surface-mounted 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 outer case for accommodating the entire core, and the core and the outer case are transparent from the direction in which the hollow portion is arranged in the left-right lateral direction. It is characterized in that it is adhesively fixed at least in one upper corner and one lower corner in the visual field.

It is possible to provide a coil that can be mounted on a circuit board with high reliability such as vibration resistance.

It is a figure explaining the outline of the surface mount coil of this embodiment, and the manufacturing method thereof. It is a figure explaining the test result of the impact resistance test (destruction test) when the application pattern of the fixing agent (adhesive) is changed by three types. It is a figure explaining the experiment for confirming the influence on the electrical property of the amorphous core with respect to the adhesive coating area. It is a figure explaining the result of having measured the change of the electric property by changing the coating area of a fixing agent. It is a figure explaining the structure which prevents the lead wire from bending in order to further improve the impact resistance characteristic. It is a perspective view explaining the appearance of the surface mount coil of this embodiment. It is a perspective view explaining the appearance of the bottom surface side of the surface mount coil of this embodiment. It is a figure explaining the internal structure which removed the outer 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 transparent field of view from the direction in which the hollow portion of the amorphous core is arranged in the left-right lateral direction. The structure is such that the two corners located vertically, more preferably the two diagonal upper and lower corners diagonally to the hollow portion, are adhered and fixed to each other. In other words, for a horizontally placed cylindrical amorphous core, at least two places, one at the top and one at the bottom, are included, and more preferably, around the above two places so that the adhesive area does not become too large. It shall be adhesively fixed to the outer case, including the above. 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.

Further, since the "corner" is adhesively fixed, it is assumed that the vicinity of the uppermost surface corner and the upper end of the vertical side wall following the uppermost surface corner is adhesively fixed, and similarly, the vicinity of the lowermost surface corner and the lower end of the vertical side wall following the lowermost surface corner is included. It shall be adhesively fixed with. By adopting such a configuration, it is possible to obtain a surface-mounted coil component having extremely high vibration resistance and impact resistance without adversely affecting the inductance characteristics. This makes it applicable to applications that require high reliability, such as those for automobiles.

Further, in the surface mount coil described in the present embodiment, more preferably, when the lead wire of 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, the lead wire of the lead wire is used. Soldered integrally with a pair of auxiliary terminals arranged on the bottom surface of the outer case adjacent to both sides of the end. Further, the auxiliary terminal may be provided by insert molding and is fixed to the outer case.

Therefore, the area of soldering can be increased as compared with the case where only the lead wire is soldered, so that it is possible to mount the product more firmly with increased impact resistance and vibration resistance. .. Therefore, the embodiments will be described in detail below with reference to the drawings.

FIG. 1 is a diagram illustrating an outline of the surface mount coil of the present embodiment and a method of manufacturing the same. As shown in FIG. 1, first, a lead wire 1200 made of 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 arranged in the outer case 1100 to which the fixing agents 1810 (1) and 1810 (2) are previously applied to the corners thereof, and the outer case 1100 is attached to the fixing agent 1810 ( 1), 1810 (2) are engaged so as to be in diagonal positions (d). Finally, the lead wire 1200 is bent along the outer case 1100 (e). Such manufacturing / assembling work may be performed manually, or a part thereof may be performed manually and other work may be performed as an automatic process by a mechanical process.

FIG. 2 is a diagram illustrating test results of an impact resistance test (destruction test) when the coating pattern is changed between three types when the same type of fixing agent (adhesive) is used. The fracture resistance due to the difference in the adhesive position and the adhesive area was measured by the tensile strength using the measuring instrument "RZ-100 / AIKOH (FS: 1kN)" by changing the application position and the application amount of the adhesive. The shape is maintained when a φ1.6 mm copper wire is passed through the hollow part of the core through a small hole (φ2 mm) made on the side of the outer case, the lower part of the outer case is fixed with a vise, and then the wire is pulled upward. It is a measurement of the critical strength to be made.

As can be understood from FIG. 2, in the lateral perspective in which the hollow portion of the amorphous core that has been seen through is observed in the left-right direction, when the coating amount is the same, the amorphous core is applied to two places above and below the center of FIG. 2 (a). 2 (b) and 2 (c), which are coated so as to include the upper and lower corners of the amorphous core, have higher fracture strength and have greater impact resistance than the coating pattern shown in 1. You can see 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 corners, respectively, and more preferably to apply the adhesive so as to include the diagonal upper and lower corners. In other words, it is preferable to apply the fixing agent to the end portion that is line-symmetrical with respect to the virtual line connecting the openings of the hollow portion of the hollow cylindrical amorphous core or point-symmetrical with respect to the center point of the virtual line. ..

Further, FIG. 3 is a diagram illustrating an experiment for confirming the influence of the adhesive application area on the amorphous core 1800 on the electrical characteristics of the amorphous core 1800. As shown in FIG. 3A, various amounts of the fixing agent were applied to the four corners in a state where the hollow portion of the amorphous core 1800 inserted in the outer case 1100 was observed in the left-right lateral direction in the transparent view. A lead wire 1200 was passed through the hollow portion of the amorphous core 1800, a current of 30 A was passed, and the change in the inductance thereof was measured. Further, as shown in FIG. 3B, the adhesive area in the case of the adhesive having the smallest coating amount of 7 mg per site and 28 mg in total at 4 sites is about 90 mm ² , and the maximum is 40 mg per site at 4 sites. In the case of a total of 160 mg of the fixing agent, the adhesive area was about 270 mm ² , and the coating area (coating amount) was changed for a total of 5 patterns including that period. For comparison, the electrical characteristics when no fixing agent was used were also measured.

FIG. 4 is a diagram illustrating the results of measuring the inductance by applying a fixing agent by changing the coating area of the fixing agent, passing a current of 30 A before and after curing, respectively. The degree of decrease in the inductance measured after the fixing agent is cured is shown based on the inductance measured before the fixing agent is cured in each coating area of the fixing agent. In the figure of 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 fixing agent is used, the coating area is 90 mm ² (coating amount 7 mg / place), 110 mm ² (coating amount 10 mg / place), 130 mm ² (coating amount 13 mg / place), 180 mm ² (coating 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 if the coating 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 of the inductance of is over 10%. That is, it can be understood that it is preferable that the coating area is 180 mm ² (coating amount 25 mg / location) or less in order to suppress the reduction rate of the inductance before and after the curing of the fixing agent.

It is presumed that as the amount of the fixing agent applied increases, the surface area of the fixing agent attached to the core increases, which increases the stress applied to the amorphous core and affects the electrical characteristics such as inductance. Since the amorphous core shown in FIGS. 3 and 4 uses a core having a surface area (excluding the hollow portion) of 300 cm ² , the ratio of the fixing agent application area to the total surface area of the core is suppressed to 60% or less. This makes it possible to keep the fluctuation of the inductance within a range that does not substantially adversely affect the electrical characteristics. In this way, it is preferable to have a large coating amount in consideration of impact resistance, but on the other hand, it is preferable to limit the coating amount in consideration of electrical characteristics, and more specifically, the balance between the two. It is preferable to adjust the coating amount so that the ratio of the coating area of the fixing agent to the total surface area of the core is 60% or less. This makes it possible to realize a surface mount coil having both good impact resistance and good inductance characteristics.

Further, FIG. 5 is a diagram illustrating a structure for preventing bending of the lead wire 1200 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 left-right lateral direction in the perspective, and the reinforcing portion 1250 of the lead wire 1200 is provided only inside the outer case 1100, typically the hollow portion of the core. It is described that the reinforcing portion 1250 described in FIGS. 5 (b) and 5 (c) is formed between the outer wall of the hollow core portion and the inner wall of the exterior case 1100 having a clearance of about 0.5 mm on each side. .. Note that 1810 (1) and 1810 (2) shown in FIG. 5A schematically show typical application locations of the fixing agent.

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

When the lead wire 1200 is bent along the outer surface of the outer case 1100 to connect to the circuit board on the bottom surface of the outer case 1100, in the case of a flat-plated copper wire without a reinforcing portion 1250, the lead wire 1200 is amorphous. The portion arranged in the hollow portion of the core is liable to bend due to some bending so as to bulge. Even if it is curved, it has no effect on the electrical characteristics, but it exhibits a shape that slightly bulges outward not only inside the exterior case 1100 but also on the side surface of the case. As a result, unexpected stress such as lifting is applied to the lead wire 1200 arranged on the bottom surface side of the mounting surface of the surface mounting coil on the substrate, which 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, the bending inside the outer case 1100 can be eliminated, and the bending on the side surface and the 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, but is a known shape such as a concave portion or a convex portion having a function of preventing bending of the lead wire, and fits inside the hollow portion of the core. Any shape / configuration can be adopted and applied as long as it is. Further, the reinforcing portion 1250 may be provided on a part or all of the portion housed inside the outer case 1100 of the lead wire 1200. Next, an outline of the overall configuration of the surface mount coil of the present embodiment will be described.

FIG. 6 is a perspective view illustrating the appearance of the surface mount coil 1000 of the present embodiment. The surface mount coil 1000 includes an outer case 1100 molded of an epoxy resin or the like. The outer case 1100 is composed of an upper outer case 1110 and a lower outer case 1120. Inside the outer case 1100, a recess (not shown) that matches the shape of the amorphous core to be housed is formed.

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. In addition, a support member (support member or guide member) for fixing and supporting 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 stretched downward, and is again on the bottom surface at the bottom surface of the outer case 1100. It is bent along and the bottom surface portion is soldered to a footprint (pad) or the like of a circuit board. Further, as shown in FIG. 6, a pair of auxiliary terminals 1300 and 1400 arranged so as 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, it is assumed that the auxiliary terminals 1300 and 1400 are not electrically connected to the lead wire 1200 (1) and are fixed to the lower outer case 1120.

Further, FIG. 7 is a perspective view illustrating the 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 of the outer case 1100 and the opposite side surface, and extends to the bottom surface along the side surface of the outer case 1100, respectively.

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. Therefore, it is preferable that the lead wire 1200 (1) and the auxiliary terminals 1300 and 1400 have the same protrusion height on the bottom surface, and it is more preferable that the bottom surface as a whole is flush with each other.

Further, as shown in FIG. 7, the lead wire 1200 (2) on the opposite end side of the lead wire 1200 (1) can also be soldered to one footprint integrally with the auxiliary terminals 1500 and 1600. .. As a result, the soldered area and the amount of solder used are larger than those in the case of only the lead wire 1200 (hereinafter, the lead wire 1200 (1) and the lead wire 1200 (2) are appropriately collectively referred to as the lead wire 1200). , The soldering strength is increased, and the reliability such as impact resistance can be improved. Further, as compared with the case where the surface mount coil 1000 is connected to the circuit board only with the lead wire 1200, by providing the auxiliary terminals 1500 and 1600, the fixed 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 that bears the electrical connection can be reduced, and the electrical connection can be further stabilized.

Further, in the coil component state before soldering shown in FIGS. 6 and 7, the auxiliary terminals 1300, 1400, 1500, and 1600 can be electrically independent and not connected to each other, and lead wires can be obtained. It can be assumed that the 1200 is not electrically connected.

Further, when soldered to the circuit board, the lead wire 1200 (1) and the auxiliary terminals 1300 and 1400 observed on the front side in FIG. 7 are electrically connected to each other via the solder, and further. The lead wires 1200 (2) on the opposite end side and the auxiliary terminals 1500 and 1600 observed on the inner side of FIG. 7 are electrically connected to each other via 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-square 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 or the like, so that the fixing strength is sufficiently high.

FIG. 8 is a diagram illustrating an internal configuration in which the exterior case 1100 of the surface mount coil 1000 is removed. FIG. 8 (a) describes an internal state in which both the upper exterior case 1110 and the lower exterior case 1120 are removed, and FIG. 8 (b) describes an internal state in which the upper exterior case 1110 is removed, FIG. 8 (c). Describes the internal state in which the lower exterior case 1120 is removed.

In FIG. 8A, the amorphous core 1800 has a hollow cylindrical shape, and a lead wire 1200 is inserted through the hollow portion. That is, the above-mentioned lead wire 1200 (1) and lead wire 1200 (2) correspond to 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 strip-shaped ribbon of an amorphous magnetic alloy, which is a high magnetic material, and sintering the ribbon. 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. There is.

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. Further, the upper exterior case 1110 and the lower exterior case 1120 can be firmly fitted and fixed to each other by using, for example, an adhesive.

Further, in FIGS. 8 (b) and 8 (c), a fixing member 1810 such as an adhesive can be applied to a predetermined portion of the amorphous core 1800, and the upper exterior case 1110 and the lower exterior case 1120 and the amorphous core can be applied. It can be assumed that the 1800 and the 1800 are more firmly fixed by the fixing member 1810, respectively.

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 embodiment, and are appropriately within the scope of those skilled in the art and within the scope of the technical idea of the present invention. The configuration, usage method, and manufacturing method can be changed.

The present invention is suitable for various in-vehicle electronic components, surface-mounted coils, and electronic components mounted on circuit boards that are required to have vibration resistance and impact resistance.

1000 ... Surface mount coil, 1100 ... Exterior case, 1110 ... 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 ... Fixed member.

Claims (5)

With a hollow cylindrical core,
A coil comprising an exterior case for accommodating the entire core.
The core and the outer case are
In the perspective from the direction in which the hollow portion of the core is arranged in the left-right lateral direction, it is adhesively fixed at least at one of the upper and lower corners.
The core is a coil characterized by being a core formed by winding a strip-shaped magnetic alloy ribbon and sintering it. In the coil according to claim 1,
The exterior case is composed of a lower exterior case including the bottom surface and accommodating a substantially lower half of the core, and an upper exterior case fitted to the lower exterior case and accommodating a substantially upper half of the core.
The core and the lower exterior case are adhesively fixed at a first position including the lower left corner or the lower right corner of the core in a transparent field of view from the direction in which the hollow portion is arranged in the left-right lateral direction.
The core and the upper exterior case include a second upper right corner or upper left corner of the core that diagonally faces the first portion in a perspective view from the direction in which the hollow portion is arranged in the left-right lateral direction. A coil characterized by being adhesively fixed at a location. In the coil according to claim 1 or 2.
A coil characterized in that the area to be adhesively fixed to the core 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.
A lead wire penetrated in the hollow portion of the core is provided.
The lead wire led out from the side surface of the outer case to the outside is bent and exposed along the outer surface of the outer case from the side surface to the bottom surface of the outer case.
A coil characterized in that a reinforcing means for preventing bending is formed in at least a part of a portion of the lead wire penetrated through the hollow portion. In the coil according to claim 2 ,
The core and the upper exterior case are adhesively fixed to the uppermost corner of the core and the vicinity of the upper end of the vertical side wall following the uppermost corner, and the core and the lower outer case are the lowermost corners of the core. A coil characterized in that the vicinity of the lower end of the vertical side wall following the lowermost corner is adhesively fixed.

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