JPH029523Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Purpose of the Invention] (Field of Industrial Application) The present invention relates to a coil device, and particularly to a coil device for the purpose of magnetic shielding.

(Conventional technology) For example, VTR (video tape recorder) and CTV
2. Description of the Related Art Conventionally, there is a coil device as shown in FIG. 1, which is used in places such as color televisions where electromagnetic interference is inconvenient or where installation space is narrow.

That is, in FIG. 1, reference numeral 1 indicates a ferromagnetic pot core in the shape of a cylinder with a circular inner bottom, and reference numeral 2 indicates a cylindrical body 3 with flanges 4A and 2 at both ends. 4B, and a collar portion 4A.
This is a ferromagnetic or paramagnetic drum core in which electrodes 5A and 5B are formed by providing a metal film in a recess formed in the outer end surface of each of the drum cores 5A and 4B. Further, a coil 6 formed by winding a conductive wire is formed on the outer periphery of the cylindrical body 3, and both ends of the conductive wire serve as coil lead wires 7A, 7B.
4B to the outer end surface of the electrodes 5A,
5B is electrically connected to one end of lead terminals 8A and 8B by solder 9 or the like. In this way, the drum core 2 with the lead terminals 8A and 8B having the coil 6 is arranged in the pot core 1,
The other ends of lead terminals 8A and 8B are connected to the pot core 1.
A magnetically shielded coil device 10 is constructed by filling a molding agent 41 made of synthetic resin into the space within the pot core 1 so as to protrude from the opening of the drum core 2 and to fix the arrangement of the drum core 2.

(Problem to be solved by the invention) However, in the coil device 10 having the above configuration, the coil lead wires 7A, 7B are drawn out from both ends of the conductive wire to the outer end surfaces of the flanges 4A, 4B.
are pulled out without any protection, so when the drum core 2 is placed inside the pot core 1, the coil lead wires 7A, 7B contact with the inner wall of the pot core 1, causing the coil lead wires 7A, 7B to come into contact with the inner wall of the pot core 1.
This caused the 7B wire to break. Also, coil 6
In order to directly fix the drum core 2 provided with the molding material 41 in the pot core 1 with the molding material 41, the molding material 41
There was a problem in that the coil lead wires 7A and 7B were caused to break due to thermal stress due to expansion and contraction caused by thermal changes. In particular, in light of the recent miniaturization of electrical components, the use of ultra-fine conductive (coil) wires with a diameter of around 0.03 mm has increased the risk of frequent disconnection accidents as described above. be.

Incidentally, in order to absorb thermal stress from the exterior material (exterior resin, casting resin, etc.) of the component element, a buffering agent is generally used between the exterior material and the component element. However, in this case, a softer material is used as the buffer material compared to the exterior material, so as mentioned above, this buffer material is Since the coefficient of linear expansion is large, there was a problem that the coil would break due to expansion and contraction due to the heat of the buffer.

The present invention has been developed based on the above-mentioned circumstances, and an object of the present invention is to provide a high-quality coil device that is less prone to disconnection accidents due to mechanical stress or thermal stress.

[Structure of the invention] (Means for solving the problem) In order to achieve the above object, the present invention has a collar having an electrical connection part and a body part around which a conductive wire is wound, and the connection part has the above-mentioned wire. In a coil device in which a conductive wire terminal is drawn out and a drum core to which one end of a lead terminal is connected is fixed with a casting agent in a bottomed cylindrical pot core such that the other end of the lead terminal is led out. , a first protective layer made of a non-flexible resin is formed on the entire surface of the drum core including the conductive wire and the lead terminal connection portion, and a second protective layer made of a flexible resin is formed on the first protective layer. It is characterized by:

(Function) Thermal stress caused by the casting agent can be absorbed by the second protective layer made of flexible resin, and the thermal stress generated in the second protective layer itself can be absorbed by the conductive wire due to the presence of the first protective layer. Since the damage does not extend to the wire itself, disconnection accidents can be prevented.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings. FIG. 2 is a sectional view showing an embodiment of the coil device according to the present invention.

In FIG. 2 showing the present invention, the difference from FIG. 1 showing the conventional example is that the collar parts 4A and 4B having electrodes 5A and 5B and the body part 3 around which a conductive wire (hereinafter also referred to as conductive wire) is wound. and a lead terminal 8A,
A protective layer 21 made of resin is formed on the entire circumferential surface of the drum core 2 which is electrically connected to both ends of the conductive wire at the electrodes 5A and 5B. This protective layer 21 includes a first protective layer 21A made of phenol epoxy resin or non-elastic silicone resin, and a second protective layer 2 made of elastic silicone resin formed on the upper surface of the first protective layer 21A.
1B. The above-mentioned drum core 2 before being placed in the pot core 1 in this way
A first protective layer 21A is applied to the entire circumferential surface of the mold, and a second protective layer 21B is further applied to the upper surface of the protective layer 21A. The drum core 2 to which 21 has been applied is placed, and then the casting agent 41 is solidified under certain heating conditions to obtain the coil device 20 shown in FIG. It should be noted that the members in FIG. 2 that are the same as those in the conventional structure shown in FIG. 1 have the same functions and are therefore given the same reference numerals.

The coil device 20 configured as described above includes a drum core 2 in which a conductive wire is wound and conductive wire lead wires (also referred to as coil lead wires) 7A and 7B are drawn out.
Since the drum core 2 is coated with a protective layer 21 consisting of a first protective layer 21A and a second protective layer 21B, the coil lead wires 7A and 7B do not come into contact with the inner wall of the pot core 1 when the drum core 2 is placed inside the pot core 1. Since the protective layer 21 (particularly the first protective layer 21A) protects the coil lead wires 7A, 7B even when the coil lead wires 7A, 7B are disconnected, it is possible to prevent the coil lead wires 7A, 7B from breaking.
Further, since the protective layer 21 (particularly the flexible resin as the second protective layer 21B) absorbs the thermal stress of the casting agent 41, disconnection of the coil lead wires 7A and 7B due to the thermal stress can be prevented. Furthermore, even if thermal stress occurs in the second protective layer made of a flexible resin, the first protective layer made of a hard resin is not affected, so the coil will not be disconnected. Therefore, it is possible to obtain a product that does not cause a coil disconnection accident even with the thermal stress of the casting resin that occurs when this thermal change is repeated many times under conditions of -20°C to 80°C, for example.

Here, the coefficient of linear expansion of each member is shown as a reference for proving the above effect.

(1) First protective layer made of non-flexible resin Epoxy melamine resin 2×10 ^-5 /℃ (2) Second protective layer made of flexible resin Silicone resin 22×10 ^-5 /℃ (3) Ferrite core 0.7 ×10 ^-5 /℃ (4) Casting resin Acrylate resin 13×10 ^-5 /℃ (5) Coil 4.7×10 ^-5 /℃ In other words, the linear expansion coefficient of the ferrite core, coil, and first protective layer is The coefficients of linear expansion are small and similar to each other, and both the casting resin and the second protective layer have large coefficients of linear expansion. Because of this relationship, the above effects can be obtained.

One embodiment of the present invention has been described above, but
The present invention is not limited to the above embodiments,
It goes without saying that the invention can be modified and implemented as appropriate without changing the gist of the invention. For example, as shown in FIG. 3, the ends of the coil lead wires 17A, 17B of the coil 16 are tied around one end of two lead terminals 18A, 18B driven into the outer end surface of one of the flanges 14A of the drum core 12. A protective layer 2 consisting of a first protective layer 21A and a second protective layer 21B is attached to the drum core 12 which is electrically connected to solder or the like.
1 is coated with the lead terminals 18A, 18.
B is placed in a cylindrical pot core 11 with a bottom such that the other end thereof protrudes from the opening of the pot core 11;
A casting agent 41 may be filled in between. Also,
As shown in FIG. 4, instead of the lead terminals 8A and 8B in the embodiment shown in FIG. The lead terminals 28A and 28B may each be bent outward. Other symbols used in FIG. 4 are the same members as in FIG. 2, so they are given the same symbols. Furthermore, the pot core 1 or 11 used in the embodiment of the present invention may be a rectangular core with an opening and a quadrilateral bottom, as shown in FIG.
As shown in FIG. 6, the core may have a semicircular bottom surface with an opening.

[Effects of the invention] As explained above, the present invention is constructed by forming two different kinds of protective layers on a drum core around which a coil is wound and electrically connecting both ends of the coil and a lead terminal. By doing so, it is possible to provide a high-quality coil device that is less prone to disconnection accidents due to mechanical stress or thermal stress.

[Brief explanation of the drawing]

Figure 1 is a sectional view showing a conventional coil device, Figure 2 is a sectional view showing a conventional coil device.
The figure is a sectional view showing one embodiment of the coil device according to the present invention, FIGS. 3 and 4 are sectional views showing other embodiments, and FIGS. 5 and 6 are sectional views showing other usage examples of the pot core. It is a schematic perspective view. 1, 11... Pot core, 2, 12... Drum core, 3... Body, 4A, 4B, 14A... Tsuba,
8A, 8B, 18A, 18B, 28A, 28B...
... Lead terminal, 41 ... Casting agent, 21 ... Protective layer, 21A ... First protective layer, 21B ... Second protective layer.

Claims (1)

[Scope of utility model registration request] A drum core having a flange having an electrical connection part and a body part around which a conductive wire is wound, the end of the conductive wire being pulled out to the connection part and one end of a lead terminal connected to the drum core is placed inside a cylindrical pot core with a bottom. In the coil device in which the other end of the lead terminal is fixed with a casting agent so that the other end is guided outside, a first protection made of a non-flexible resin is provided on the entire surface of the drum core including the conductive wire and the lead terminal connection part. A second protective layer made of flexible resin is formed on the first protective layer.
A coil device characterized by forming a protective layer.