CN108461923B

CN108461923B - Coil device for antenna and method for manufacturing the same

Info

Publication number: CN108461923B
Application number: CN201810167053.0A
Authority: CN
Inventors: 马原繁
Original assignee: Sumida Group Co ltd
Current assignee: Sumida Group Co ltd
Priority date: 2013-06-19
Filing date: 2014-06-04
Publication date: 2020-09-25
Anticipated expiration: 2034-06-04
Also published as: JP2015005810A; CN108281793A; JP6186924B2; CN108461923A; CN104241861B; CN104241861A; CN108281793B

Abstract

The invention provides a coil device for an antenna and a method for manufacturing the same. The coil device for an antenna includes: a core made of a magnetic material; a coil bobbin including a winding shaft portion and attached around the core; and a coil wire wound around the winding shaft, wherein the coil bobbin is a single member integrally formed of a resin material, and includes a plurality of base pieces, one ends of which are connected together, and the other portions of which are separated from each other, and the base pieces are closely attached to the core. The present invention can provide a coil device for an antenna using a coil bobbin with high productivity by injection molding.

Description

Coil device for antenna and method for manufacturing the same

The present application is a divisional application of an invention patent application having an application date of 2014, 6/4, No. 201410244691.X and entitled "coil bobbin and coil device for antenna using the same".

Technical Field

The present invention relates to a coil device for an antenna and a method of manufacturing the same.

Background

As a conventional antenna coil device, a transmitting antenna coil described in patent document 1 is known. In the transmitting antenna coil, a plurality of annular flange portions are formed around an elongated cylindrical coil bobbin in which a rod-shaped magnetic core is accommodated, and an electric wire is wound around the coil bobbin. On one side surface in the circumferential direction of the coil bobbin, a window-like opening is further formed between the flange portions. The coil bobbin is made of a resin material such as polyethylene terephthalate (PBT) and is manufactured by Injection Molding (Injection Molding) using a mold.

Documents of the prior art

Patent documents:

1. japanese laid-open patent publication No. 2005-175965

Disclosure of Invention

The technical problem to be solved is as follows:

the conventional cylindrical coil bobbin of patent document 1 is formed of resin using 3 division molds. In the coil bobbin, when the winding axis direction is defined as the Z direction and an arbitrary direction perpendicular thereto is defined as the X direction, a pair of vertical split dies (a fixed side and a movable side) which can move in contact with and apart from each other in the ± X direction and a male die which can advance and retreat in the ± Z direction are generally used as the split dies.

A male mold for molding the hollow of the inner cavity of the cylindrical coil bobbin is called a slider mold, and has a rod-like portion having the same shape as the magnetic core. The upper and lower split molds are arranged to face each other to form a closed space therein, and molten resin is injected into the closed space in a state where the male mold is accommodated in the closed space. After the molten resin is cured, the male mold is removed in the Z direction, thereby forming a hollow accommodating space for accommodating the rod-like magnetic core. Then, the coil bobbin molded into an elongated cylindrical shape is taken out by separating the upper and lower split molds from each other.

That is, the conventional coil bobbin requires a space in the ± X direction in which the vertical split type die can move, and further requires a movement space for inserting and extracting the male die in the Z direction perpendicular to the X direction. Therefore, it is difficult to miniaturize the injection molding machine for coil bobbin molding, in other words, to increase the number of parts to be molded simultaneously in the case of simultaneously forming a plurality of coil bobbins using the injection molding machine.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a coil bobbin with high injection molding productivity, and a coil device for an antenna using the coil bobbin.

The technical scheme is as follows:

the present invention provides a coil device for an antenna, including: a core made of a magnetic material; a coil bobbin including a winding shaft portion and attached around the core; and a coil wire wound around the winding shaft; the method is characterized in that: the coil bobbin is a member integrally molded from a resin material and includes a plurality of base pieces; one ends of the base plates are connected together, and the other parts are in a separated state, and the base plates are tightly attached to the iron core.

Further, according to the present invention, there is provided a method of manufacturing a coil device for an antenna, the coil device for an antenna including: a core made of a magnetic material; a coil bobbin including a winding shaft portion and attached around the core; and a coil wire wound around the winding shaft; the manufacturing method comprises the following steps: preparing a split mold; and a step of injecting resin into the mold to form an integrally molded component including the coil bobbin, wherein: the coil bobbin after molding comprises a plurality of base pole pieces; one ends of the base plates are connected together, and the other parts are in a separated state, and the base plates are tightly attached to the iron core.

Has the advantages that:

according to the present invention, it is possible to provide a coil device for an antenna with high productivity using a coil bobbin with high productivity by injection molding.

Drawings

Fig. 1 is a perspective view showing an antenna coil device according to a first embodiment of the present invention.

Fig. 2 is a perspective view of the coil bobbin of the first embodiment.

Fig. 3 is a sectional view taken along line III-III in fig. 1.

Fig. 4(a) is a sectional view taken along line IV-IV in fig. 2. Fig. 4(b) is an explanatory view showing a molding state of the winding shaft portion.

Fig. 5 is a sectional view taken along line V-V in fig. 2.

Fig. 6(a) is a cross-sectional view showing a winding shaft portion of the second embodiment. Fig. 6(b) is an explanatory view showing a molding state of the winding shaft portion.

Fig. 7(a) is a cross-sectional view showing a winding shaft portion of the third embodiment. Fig. 7(b) is an explanatory view showing a molding state of the winding shaft portion.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In all the drawings, the same components are denoted by the same reference numerals, and overlapping description thereof will be omitted as appropriate.

Fig. 1 is a perspective view showing an antenna coil device (coil device 100) according to a first embodiment of the present invention. Fig. 2 is a perspective view of the coil bobbin 20 of the present embodiment. Fig. 3 is a sectional view taken along line III-III in fig. 1.

First, an outline of the present embodiment will be described. The coil apparatus 100 has a core 10, the core 10 being made of a magnetic material; a coil bobbin 20, the coil bobbin 20 having a winding shaft portion 22 and being attached around the core 10; and a coil wire 50, the coil wire 50 being wound around the winding shaft portion 22. The coil bobbin 20 is constructed as one member integrally molded from a resin material; meanwhile, a projection onto any one region of the coil bobbin 20 in at least one direction (X direction) intersecting the extending direction of the winding shaft portion 22 does not overlap with other regions of the coil bobbin 20.

Here, the projection onto the coil bobbin 20 in one direction means a shadow in the case where visible light is projected onto the coil bobbin 20 from a certain direction. The fact that the projection onto any one region of the coil bobbin 20 does not overlap with the other regions of the coil bobbin 20 means that the shadow region is not visible when the coil bobbin 20 is viewed.

Next, the coil device 100 of the present embodiment will be described in detail.

The coil device 100 is used for an antenna device. The coil device 100 for a field antenna in the present embodiment is a coil device 100 in which a coil wire 50 is wound around a core 10, and the coil wire 50 wound around the core 10 and a capacitor (not shown) connected in series with the coil wire constitute a tuning circuit. The core 10 is made of a magnetic material having a high magnetic permeability such as ferrite. The core 10 of the present embodiment has a rod shape and constitutes an open magnetic path structure. The shape of the core 10 is not limited to the rod shape. The coil wire 50 is a wire whose surface is covered with an insulating film. The coil device 100 of the present embodiment is a bar antenna. The antenna device has various applications, but as an example, it can be used as a transmitting antenna device on the vehicle side of a smart electronic key system for a vehicle. In the intelligent electronic key system, when a driver with an electronic key approaches a vehicle and enters the communication field of the system, an antenna coil device communicates with the electronic key, and a vehicle-side control loop connected to the antenna coil device permits the driving of a door to unlock and the starting of an engine. Conversely, when the driver with the electronic key gets out of the communication area of the system while away from the vehicle, the control circuit on the vehicle side is driven again to lock the door.

The coil bobbin 20 has an elongated, partially cylindrical shape capable of accommodating the core 10. In the present embodiment, the partially cylindrical shape means a hollow shape in which an outer peripheral surface is not present over the entire peripheral surface, but a part of the region in the outer peripheral direction is covered as in the example of the C-shaped cross section. In the coil bobbin 20 of the present embodiment, the winding shaft portion 22, the bobbin end portion 26b, and the stopper portion 27, which are the housing areas of the core 10, are all partially cylindrical.

The coil bobbin 20 is formed by Insert Molding (Insert Molding) a pair of antenna terminals 40 and a plurality of binding terminals 42 made of a metal material with a resin material. The antenna terminal 40 and the binding terminal 42 are individually connected together. Both ends of the coil wire 50 are wound around the pair of binding terminals 42.

In the coil device 100 shown in fig. 1, the coil wire 50 is wound around the winding shaft 22 of the coil bobbin 20, but the form of the coil device 100 is not limited to this. For example, a connector (not shown) for connection to a control circuit on the vehicle side may be attached to the antenna terminal 40.

Around the winding shaft portion 22, a projection portion 30 for preventing the coil wire 50 from being misaligned in winding is further formed. Specifically, the plurality of projections 30 are formed at a plurality of positions at intervals along the winding axis direction (Z direction) of the winding axis portion 22. The coil electric wire 50 is wound between the protruding portions 30 around the winding shaft portion 22 in a multi-layer winding form, and is finally wound around the binding terminal 42.

The coil wire 50 wound around the winding shaft 22 may have a coating resin (not shown) formed by OVER-MOLDING (OVER-MOLDING). The coating resin preferably covers the entire length of the core 10 and the binding terminals 42, that is, substantially all of the coil bobbin 20 except for the vicinity of the antenna terminal 40, in addition to the winding shaft 22.

The form of the coil bobbin 20 will be further described. The winding direction of the coil wire 50 with respect to the coil bobbin 20, i.e., the extending direction of the winding shaft 22 is defined as the Z direction. The core 10 of the present embodiment has a flat bar shape. In a cross section (cross section) of the core 10 cut perpendicular to the longitudinal direction, a short side (thin wall) direction is taken as an X direction, and a long side (wide width) direction is taken as a Y direction. In the coil bobbin 20 of the present embodiment, the injection molding process of the resin material can be performed by using only a die (divided die) that is close to or apart from one direction (X direction in the present embodiment) without using a male die that is inserted and removed in the Z direction. The shape of the entire cross section of the coil bobbin 20 is not such that a plurality of cross-sectional portions are arranged in parallel in the X direction in the approaching or separating (dividing) direction of the divided dies. That is, when the coil bobbin 20 is cut along any one cross section including the X direction in the same plane, there is no case where there are cross-sectional portions on both sides in the X direction with the hollow portion interposed therebetween. In other words, all arbitrary straight lines having the X direction as a direction vector intersect the coil bobbin 20 at most 1 time. That is, when the coil bobbin 20 is cut along any one cross section including the X direction in the same plane, when any part of the coil bobbin 20 is projected in the X direction in this cross section, the projection thereof does not overlap with other parts. The coil bobbin 20 is in a shape of being gathered in a bundle in the approaching or separating direction of the division mold. Therefore, the coil bobbin 20 has a shape in which a projection onto an arbitrary region of the coil bobbin 20 does not overlap with other regions in at least one direction (X direction) intersecting with the extending direction (Z direction) of the winding shaft portion 22. Thus, the coil bobbin 20 can be injection molded as one part by a pair of divided molds approaching or separating in the one direction (X direction).

The coil bobbin 20 is formed of a single member integrally molded with a resin material, and includes the winding shaft portion 22, and the winding shaft portion 22 is a member that can be manufactured by injection molding of the resin material using only the divided molds that are close to or apart from each other in one direction (for example, the X direction) as described above. As an alternative to this embodiment, another member may be additionally attached to the coil bobbin 20.

The above description is merely illustrative of the shape of the coil bobbin 20 at the time of injection molding, and does not mean the shape of the coil bobbin 20 in the state of the coil apparatus 100 in which the coil wire 50 is wound therearound.

As shown in fig. 3, the core 10 in the present embodiment has a bar shape with a rectangular cross section. The first or second base pieces 24a to 24c (the

second base pieces

24a and 24b in the present embodiment) have an L-shaped cross section that holds the corner 12 of the rectangular cross section of the fixed core 10. In addition, the cross-sectional shape of the winding shaft portion 22 of the coil bobbin 20 forms a part of a quadrangular shape surrounding the core 10. The cross-sectional shape is a part of a quadrangular shape, and does not mean a full-perimeter shape having four sides, but means a shape including a part or all of each of the four sides. In the present embodiment, as shown in fig. 3, the winding shaft 22 is constituted by a first base piece 24c having a simple linear cross-sectional shape and a pair of

second base pieces

24a, 24b having L-shaped cross-sections. In the cross section shown in fig. 3, the two opposite sides extending in the X direction are each formed by the entire side length. And opposite sides extending in the Y direction are each formed by a part of the side length.

The coil wire 50 is wound around the core 10 in a non-contact manner. In the cross section of the coil apparatus 100, the base pieces 24a to 24c form a part of a quadrangular shape surrounding the core 10, so that the coil wire 50 does not contact any peripheral surface of the core 10. That is, the coil wire 50 is wound around the winding shaft 22 in a non-contact manner with respect to the core 10.

The winding shaft 22 of the coil bobbin 20 in this embodiment is compressed by the wound coil wire 50 and is pressed tightly around the core 10. That is, the form of the winding shaft portion 22 at the time of molding the coil bobbin 20 is different from the form of the winding shaft portion 22 at the time of winding the coil wire 50 in the coil device 100.

That is, the coil bobbin 20 of the present embodiment used in the coil apparatus for antenna (coil apparatus 100) is characterized in that the winding shaft portion 22 has a plurality of base pieces 24a to 24c which are configured in a compressible form. The base pieces 24a to 24c are elongated columnar portions extending in the winding axis direction on the coil bobbin 20. By winding and compressing the coil wire 50 inward, the plurality of base pieces 24a to 24c are elastically deformed to reduce the distance therebetween. Therefore, in a state where the core 10 is surrounded by the base pieces 24a to 24c, the coil wire 50 is wound around the base pieces 24a to 24c, so that the base pieces 24a to 24c are closely attached to the core 10 and the core 10 is held and fixed. The plurality of base pieces 24a to 24c are compressible, and means that the plurality of base pieces 24a to 24c can be reduced in size in a visual and reproducible manner by large deformation of the plurality of base pieces 24a to 24c themselves or large change in relative position between the plurality of base pieces 24a to 24 c.

As shown in fig. 3, the winding shaft 22 around which the coil wire 50 is wound includes a plurality of base pieces 24a to 24c arranged to be spaced apart from each other along the circumferential direction of the core 10. By the plurality of base pieces 24a to 24c, the coil wire 50 is wound around the base pieces 24a to 24c while the core 10 is held and fixed from the periphery.

When the coil wire 50 is not wound, the base pieces 24a to 24 are loose and free from the core 10. This makes it easier to insert the core 10 into the winding shaft 22 of the coil bobbin 20. In a state where the coil wire 50 is not wound, the spacing distance between the base pieces 24a to 24c becomes larger compared to the wound state of the coil apparatus 100.

Fig. 4(a) is a sectional view taken along line IV-IV in fig. 2. However, the core 10 is illustrated in fig. 4(a) for the sake of explanation. Fig. 4b is an explanatory diagram showing a molding state of the winding shaft portion 22 (see fig. 2) of the coil bobbin 20. The coil bobbin 20 (the base pieces 24a to 24c) is molded by arranging the first die 110 and the second die 120, which constitute the split mold, in opposition to each other, injecting a molten resin into the space 130 formed by the dies, and cooling and hardening the resin. The joining surface 140 is an interface extending in a direction intersecting the approaching or separating direction (X direction) of the first die 110 and the second die 120. The specific position of the engagement surface 140 is not limited to that shown in fig. 4 (b). The first die 110 has a convex portion 112. The second die 120 has a pair of

protrusions

122, 124 fitted to the protrusions 112. The protruding direction of the protruding

portions

112, 122, 124 coincides with the approaching or separating direction (X direction) of the first die 110 and the second die 120. The convex portion 112 of the first die 110 penetrates between the pair of

base pieces

24a and 24b, and serves as a portion that divides the molding space of the base piece 24 c. The

projections

122 and 124 penetrate between the

base pieces

24a and 24c and between the

base pieces

24b and 24c, and are portions that divide the corners of the L-shaped

base pieces

24a and 24b and a part of the molding space of the base piece 24 c.

As described above, the coil bobbin 20 has a shape in which a projection onto an arbitrary region of the coil bobbin 20 in at least one direction (X direction) intersecting the extending direction (Z direction) of the winding shaft 22 does not overlap with other regions of the coil bobbin 20. As shown in fig. 4(b), in the molded state of the coil bobbin 20, that is, in the state where no coil wire is wound, a gap V exists between the projection of the first base piece 24c in the one direction (X direction) and the projections of the

second base pieces

24a and 24 b. That is, the distance between the

second base pieces

24a and 24b is larger than the size of the first base piece 24c in the direction (Y direction) intersecting the approaching or separating direction of the first die 110 and the second die 120. Therefore, the convex portions 112 penetrating between the

second base pieces

24a, 24b, and the

convex portions

122, 124 penetrating between the

second base pieces

24a, 24b and the first base piece 24c may be formed in a tapered shape having a width gradually narrowing toward the projecting direction. Therefore, after the resin molding of the coil bobbin 20, the first die 110 and the second die 120 can be easily removed from the coil bobbin 20.

The coil bobbin 20 is configured in such a shape that projections of the

base pieces

24a and 24b of the coil bobbin 20 in only one direction (X direction) do not overlap with the coil bobbin 20 itself (other fields), and projections of the

base pieces

24a and 24b overlap with each other in a direction (Y direction) perpendicularly intersecting with the one direction. This makes it possible to hold and fix the core 10 well while ensuring the X direction as the approaching or separating direction of the split molds, thereby reducing the risk of the core 10 not being well held and fixed in the Y direction.

As shown in fig. 2, the

second base pieces

24a and 24b are respectively provided with a protrusion 30. The projection 30 is integrally formed from the same material as the

second base pieces

24a, 24 b. The projecting portion 30 is formed to project outward from the

second base pieces

24a and 24b in both the X direction and the Y direction.

The coil bobbin 20 is composed of a winding shaft 22 and a bobbin end 26. The bobbin end 26 may be provided only at one end of the winding shaft 22, or may be provided at both ends of the winding shaft 22. In the coil bobbin 20 of the present embodiment, bobbin end portions 26(26a, 26b) are provided on both ends in the extending direction of the winding shaft portion 22.

The bobbin end 26a is a portion formed by insert-molding the antenna terminal 40 and the binding terminal 42, and is capable of arbitrarily attaching a wire connector (not shown). The bobbin end 26b is for inserting the core 10 into the open end of the winding shaft 22. The

bobbin end portions

26a, 26b are formed more firmly than the winding shaft portion 22, and are non-compression portions that are not substantially deformed. The bobbin end 26b can be used as a holding fixing point to be clamped (chuking) by a chuck of a winder (not shown) when the coil wire 50 is wound around the winding shaft 22 of the coil bobbin 20.

The coil bobbin 20 has a shape in which not only the winding shaft portion 22 but also the

bobbin end portions

26a, 26b are injection-molded only by the first die 110 which is moved toward or away from the second die 120 in any one direction (X direction), without using a male die which is inserted and removed in the winding shaft direction (Z direction). In other words, if any portion of the bobbin ends 26a, 26b is projected in the X direction, the projection thereof does not overlap with other portions than the bobbin ends 26a, 26 b.

That is, bobbin ends 26a, 26b, which are non-compression portions, are integrally formed of a resin material on at least one end side of the winding shaft portion 22 of the coil bobbin 20 of the present embodiment. The

bobbin end portions

26a, 26b are formed in such a shape that no projection onto any region of the

bobbin end portions

26a, 26b in the above-mentioned one direction (X direction) overlaps with the other region of the

bobbin end portions

26a, 26 b.

Fig. 5 is a sectional view taken along line V-V in fig. 2, and is also a cross-sectional view of the bobbin end 26 b. The bobbin end 26b is formed in a C-shaped cross-sectional shape that opens in the approaching or separating direction (X direction) of the split mold. Therefore, injection molding can be performed using only a pair of the first die 110 and the second die 120 (not shown in fig. 5) that are close to or apart from each other in the X direction. The bobbin end 26a provided with the antenna terminal 40 has a solid center block shape except for the antenna terminal 40 and the binding terminal 42, and can be injection molded by using only a pair of the first die 110 and the second die 120 which are close to and apart from each other in the X direction.

As shown in fig. 2, the bobbin end portion 26a has a stopper portion 27 at a boundary portion with the winding shaft portion 22. The stopper portion 27 has a larger dimension than the winding shaft portion 22 in both the X direction and the Y direction, and prevents the coil wire 50 from being wound and misaligned together with the projection portion 30. The core 10 having a C-shaped cross section is inserted into the stopper portion 27 with an opening formed below (in the-X direction) (see fig. 1). The core 10 inserted from the bobbin end 26b is inserted through the coil bobbin 20 to the deepest position of the stopper 27, and contacts the bobbin end 26a having a solid center, thereby limiting the insertion depth of the core 10.

The bobbin end 26b is also larger than the dimensions of the winding shaft 22 in the X and Y directions, and has a function of preventing winding displacement disorder of the coil wire 50. The coil wire 50 may be wound over the entire length of the winding shaft 22, or may be wound over a partial length region of the winding shaft 22 as shown in fig. 1.

The winding shaft 22 of the coil bobbin 20 has the bobbin end 26b and the stopper 27, which are all partially cylindrical as described above. The winding shaft 22, the bobbin end 26b, and the stopper 27 are opened at least at 1 position in the circumferential direction around the winding shaft direction (Z direction). The opening directions of the winding shaft 22, the bobbin end 26b, and the stopper 27 may be the same direction or different directions. In the coil bobbin 20 of the present embodiment, the opening direction of the bobbin end portion 26b is the + X direction, the opening direction of the winding shaft portion 22 is the + X direction and the-X direction, and the opening direction of the stopper portion 27 is the-X direction. That is, the opening directions of the winding shaft 22, the bobbin end 26b, and the stopper 27 do not coincide with each other. This can maintain a predetermined strength of the coil bobbin 20 against an external force that pushes the opening to be large. Further, by making at least a part of the center of the length region (the coil end portion 26a) other than the housing portion of the core 10 firm, the strength and rigidity of the entire coil device 100 can be maintained.

In the coil bobbin 20, the compressible columnar base pieces 24a to 24c may be provided over the entire length of the winding shaft portion 22, or may be provided in a partial length region of the winding shaft portion 22. In other words, the base pieces 24a to 24c may be terminated at the middle position of the winding shaft 22, or may be formed over the entire length from the bobbin end 26b to the stopper 27. In the present embodiment, as shown in fig. 2, the base pieces 24a to 24c are provided in a part of the length of the winding shaft 22 without reaching the stopper portion 27, but the present invention is not limited thereto. The base pieces 24a to 24c are formed at positions not overlapping the stopper portion 27 in the winding axis direction (Z direction) of the winding axis portion 22. Thus, the coil bobbin 20 having the bobbin end 26b, the base pieces 24a to 24c, the stopper 27 and the bobbin end 26a can be molded with resin by 1 injection molding step using the first die 110 and the second die 120, which are divided molds.

In the coil apparatus 100 in the present embodiment, the coil bobbin 20 is elastic and compressible, and the coil bobbin 20 is pressed against the core 10 by the winding force of the coil wire 50. That is, the coil device 100 of the present embodiment includes the following technical ideas.

(i) A coil device for an antenna, comprising a core made of a magnetic material; a coil bobbin having a winding shaft portion and mounted around the core; and a coil wire wound around the winding shaft; the coil bobbin is integrally molded with a resin material, and the winding shaft is crimped around the core by the coil wire fastened to the winding shaft.

(ii) In the above-described coil device for an antenna, the winding shaft portion has a plurality of columnar portions and is configured in a compressible form.

(iii) In the above-described coil device for an antenna, a bobbin end portion as a non-compression portion is integrally formed with the resin material on at least one end side of the winding shaft portion.

As shown in the present embodiment, by making the coil bobbin 20 elastic and compressible, the coil wire 50 can be wound around the coil bobbin 20, and the core 10 inserted into the coil bobbin 20 can be stably held and fixed. Accordingly, in various processes performed after the step of winding the coil wire 50, for example, the step of winding both ends of the coil wire 50 around the binding terminals 42 or the overmolding step of covering the coil wire 50 with a coating resin (not shown), the core 10 is not displaced in the winding axis direction of the coil bobbin 20. This prevents an unexpected variation in antenna characteristics of the coil device 100 with respect to design specifications, and improves the yield of the coil device 100.

In addition, various modifications are also allowable with respect to the present embodiment.

For example, fig. 1 and 2 illustrate a form in which the protruding direction of the antenna terminal 40 is perpendicular to the winding axis direction (Z direction), but the present invention is not limited to this. The antenna terminal 40 may protrude in the winding axis direction. In the present embodiment, the

bobbin end portions

26a and 26b, the stopper portion 27, and the projecting portion 30 are all integrally formed with the base pieces 24a to 24c using the same material, but the present invention is not limited thereto. Any of the bobbin ends 26a, 26b, the stopper 27 or the projection 30 may be a separate component and may be mounted to the coil bobbin 20 having the base pieces 24a to 24 c.

In the present embodiment, the base pieces 24a to 24c are each in the form of a columnar elongated portion, but the present invention is not limited to this. The base sheet may also be net-shaped, planar, etc. The number (number) of the base pieces 24a to 24c is not limited to 3 in the present embodiment. As described in the embodiments described later, the number of the base pieces may be 2 or 4 or more.

The coil bobbin 20 in the present embodiment is configured such that a projection of the coil bobbin 20 does not overlap with the coil bobbin 20 itself (other region) in one direction (X direction) intersecting with the extending direction (Z direction) of the winding shaft portion 22. As an alternative to this embodiment, the coil bobbin 20 may be configured such that the projection of the coil bobbin 20 does not overlap the coil bobbin 20 itself in two or more directions (for example, the X direction and the Y direction).

Fig. 6(a) is a cross-sectional view showing the winding shaft portion 22 of the coil apparatus 100 of the second embodiment. Fig. 6(b) is an explanatory diagram showing a molding state of the winding shaft portion 22.

The coil bobbin 20 of the present embodiment is different from the first embodiment in that the winding shaft portion 22 is configured as a pair of 2L-shaped

base pieces

24a, 24 b. As shown in fig. 6(a), the core 10 is held between a pair of L-shaped

base pieces

24a and 24b arranged in point symmetry, and the cross-sectional shape of the winding shaft 22 is a part of a square shape surrounding the core 10. Therefore, the coil wire 50 is wound around the coil bobbin 20 of the present embodiment in a non-contact manner. Further, by winding the coil wire 50, the

base pieces

24a and 24b are closely attached to the periphery of the core 10, and the core 10 can be held and fixed well.

As described in the present embodiment, the winding shaft 22 is formed in 2 portions (

base pieces

24a and 24b) arranged point-symmetrically, whereby the first die 110 and the second die 120 can be formed in a symmetrical shape. Specifically, the convex portion 112 of the first die 110 and the convex portion 122 of the second die 120 may have the same tapered shape. Therefore, the productivity of the first die 110 and the second die 120 can be improved, and the coil bobbin 20 can be stably resin-molded.

Fig. 7(a) is a cross-sectional view showing the winding shaft portion 22 of the coil apparatus 100 of the third embodiment. Fig. 7(b) is an explanatory diagram showing a molding state of the winding shaft portion 22.

The coil bobbin 20 of the present embodiment is different from the first embodiment (see fig. 3) in that the first base piece 24c disposed along the side center of the core 10 is divided into a plurality of columnar shapes. That is, the base sheet 24a to 24d of the present embodiment is constituted by 4.

As shown in this embodiment, the flexibility of the winding shaft portion 22 of the coil bobbin 20 can be improved by supporting one side of the core 10 with the plurality of

base pieces

24c, 24d in the cross section of the winding shaft portion 22. And may allow relative displacement of the

base pieces

24c, 24 d. Since the compressibility of the winding shaft 22 can be improved, the coil wire 50 can be wound with a small winding pressure, and the base pieces 24a to 24d can be brought into good contact with the core 10.

The mold (divided mold) for injection molding of the coil bobbin 20 of the present embodiment is different from the second die 120 (see fig. 4(b)) of the first embodiment in that the molding space of the base piece 24c is divided into a plurality of pieces as shown in fig. 7 (b). The first die 110 is common. That is, by exchanging the second die 120, the formed coil bobbin 20 can be changed from one to another between the first embodiment and the present embodiment.

The various components of the coil device 100 of the present invention do not have to be independent of each other, and a plurality of components may be formed into one part, or one component may be formed into a plurality of parts, and a certain component may be a part of another component, or a part of a certain component may overlap with a part of another component.

The above embodiment includes the following technical ideas.

(1) A coil device for an antenna, comprising a core made of a magnetic material; a coil bobbin having a winding shaft portion and attached around the core; and a coil wire wound around the winding shaft; wherein the coil bobbin is a member integrally formed of a resin material; at the same time, in at least one direction intersecting with the extending direction of the winding shaft part, the projection to any one area of the coil bobbin is not overlapped with other areas of the coil bobbin.

(2) The coil device for an antenna according to the item (1), wherein the winding shaft portion includes a plurality of base pieces arranged at intervals along a circumferential direction of the core.

(3) The coil device for an antenna according to the above (1) or (2), wherein the core has a bar shape having a rectangular cross section, and the cross-sectional shape of the winding shaft portion of the coil bobbin is a part of a quadrangular shape surrounding the core.

(4) The coil device for an antenna according to any one of the above (1) to (3), wherein the winding shaft portion of the coil bobbin is wound and pressed around the core by the coil wire.

(5) The coil device for an antenna according to any one of the above (1) to (4), wherein a projection portion for limiting winding displacement of the wound coil wire is further formed around the winding shaft portion.

(6) The coil device for an antenna according to any one of the above (1) to (5), wherein a coating resin is further molded on the coil wire wound around the winding shaft portion.

(7) A coil bobbin used in the coil device for antenna described in any one of (1) to (6), wherein the winding shaft portion of the coil bobbin has a plurality of base pieces and is configured in a compressible form.

(8) The coil bobbin as set forth in the above (7), wherein a bobbin end portion of the non-compression portion is further integrally formed with the resin material on at least one end side of the winding shaft portion, and a projection of an arbitrary region of the bobbin end portion in the one direction does not overlap with any other region of the bobbin end portion.

(9) The coil bobbin as set forth in the above (7) or (8), wherein a gap exists between a projection of one of the base pieces and a projection of the other of the base pieces in the one direction.

(10) The coil bobbin according to the above (9), wherein the core has a bar shape having a rectangular cross section, and the base sheet has an L-shaped cross section for holding and fixing a corner portion of the rectangular cross section of the core.

Description of the symbols:

10, the ratio of the iron core to the iron core,

12, the angle part is arranged at the position,

20: a coil bobbin, wherein the coil bobbin is,

22: a winding shaft portion of the winding shaft,

24 a-24 d, a base pole piece,

26, 26a, 26b, the end of the winding tube,

27: a limiting part, wherein the limiting part,

30, the convex part is arranged on the upper surface of the base plate,

40, the antenna terminal is connected with the antenna,

42, binding the terminals, namely binding the terminals,

50: the wire of the coil,

100: a coil device, wherein the coil device,

110: the first die, the second die,

112, the convex part is arranged on the upper surface of the shell,

120: a second die, the second die,

122, 124: the convex part,

130: the space of the first layer is 130,

140, the joint surface is welded on the outer surface of the steel pipe,

v: gap

Claims

1. A method for manufacturing a coil device for an antenna, the coil device for an antenna comprising: a core made of a magnetic material; a coil bobbin including a winding shaft portion and attached around the core; and a coil wire wound around the winding shaft,

the manufacturing method comprises the following steps: preparing a split mold; and a step of injecting resin into the mold to form an integrally molded component including the coil bobbin,

the method is characterized in that: the coil bobbin after molding comprises a plurality of base pole pieces;

one ends of the base plates are connected together, while the other parts are in a separated state, and the base plates are tightly attached to the iron core,

the core is in the shape of a bar having a rectangular cross section, and the base sheet is discontinuous so that the coil wire does not contact any peripheral surface of the core by surrounding the cross section of the base sheet around each side of the rectangular cross section of the core,

the plurality of base pieces of the coil bobbin are wound with the coil wire and are pressed tightly around the core.

2. A method of manufacturing a coil device for an antenna according to claim 1, wherein: the divided mold has a first die having a convex portion and a second die having a pair of convex portions fitted with the convex portion of the first die.

3. A method of manufacturing a coil device for an antenna according to claim 2, wherein: the protruding portion of the first die and the pair of protruding portions of the second die are formed into shapes whose tips are gradually narrowed.

4. A method of manufacturing a coil device for an antenna according to claim 2, wherein: the convex part of the first die and the pair of convex parts of the second die form a first base sheet and a pair of second base sheets which are separated from each other, and the spacing distance between the pair of second base sheets is larger than the width of the first base sheet.

5. A method of manufacturing a coil device for an antenna according to claim 2, wherein: in the step of forming the integrally formed member, a bobbin end portion is further formed,

further, the method includes a step of fixing the end of the bobbin to a chuck of a winding machine and winding the bobbin after the step of forming the integrally molded member.

6. A method of manufacturing a coil device for an antenna according to claim 2, wherein: further comprising a step of winding a wire after the step of forming the integrally formed member,

in the winding step, the winding coil is compressed and deformed inward, so that the base plate is elastically deformed and closely attached to the core, thereby holding and fixing the core.