JPH0666202B2 - Current transformer - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current transformer for converting an alternating current into a voltage in a power supply circuit of various audio equipment, video equipment, industrial equipment and the like.

2. Description of the Related Art Conventionally, this type of current transformer has a structure as shown in FIGS. First, a horizontal type current transformer in which a magnetic material is horizontally inserted into a mounting surface will be described with reference to the perspective view of FIG. 4 and the side sectional view of FIG. The bobbin has an iron core insertion hole 16 into which the magnetic materials 5a and 5b are inserted, and a cylindrical portion 14 is provided on the outer periphery thereof. Upper end flanges 7 and 7a are provided at both ends of the upper portion, and lower end flanges 6 and 6a are provided at both ends of the lower portion. Further, both legs of a substantially U-shaped thick conductor 4b through which a large current flows are inserted into the upper end flange 7 and the lower end flange 6 on one side, respectively, from the tips into the holes 19 of the upper end flange 7, and further penetrate the upper end flange 7 and the lower end flange 6. Its tip is projected from the lower end collar 6. In this way, the primary coil 4 is formed. Further, the secondary coil 3 and the primary coil 4
Is a structure separated by an insulating plate 13 integrally molded of plastic.

The secondary coil 3 is wound a prescribed number of times around the tubular portion 14 of such a bobbin, and its lead lead wire 22 is wound around the base 15 of the metal pin terminal 9 that is planted in the lower end collar 6a, and is then soldered. The lead terminal 22 of the secondary coil 3 is connected to the pin terminal 9. Further, the insulating tape 17 is wound around the upper outer periphery of the secondary coil 3. Next, the E-type magnetic materials 5a and 5b
Are inserted into the bobbin insertion holes 16 from the left and right, respectively, and fixed to form a closed magnetic circuit. The shapes of the magnetic materials 5a and 5b may be EE type, EI type, or E type. Thus, the horizontal type current transformer is completed.

Next, a perspective view of FIG. 6 and a perspective view of a current transformer having a vertical structure in which a magnetic material is vertically inserted into a mounting surface are shown.
This will be described with reference to the sectional view of the drawing. The bobbin structure is the same as the horizontal type current transformer described above, and the winding process soldering method is also the same, so description thereof will be omitted. The method of inserting the magnetic materials 5a and 5b will be described. The I-shaped magnetic material 5a is inserted into the magnetic material insertion hole 16 of the bobbin.
Then, a substantially U-shaped magnetic material 5b is abutted against and fixed to the I-shaped magnetic material 5a from above the bobbin upper end flanges 7 and 7a to form a closed magnetic path. The shape of the magnetic materials 5a and 5b is changed to
Insert one leg of the U part into the magnetic material insertion hole 16 of the bobbin and
It does not matter if the part is attached to the side surface of the upper end collar 7 of the bobbin. Next, the insulating plate 13a is inserted between the magnetic material 5b and the primary coil 4 and the secondary coil 3 made of a substantially U-shaped conductor to complete a current transformer having a vertical structure.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In a horizontal type current transformer as shown in FIG. 4, the magnetic materials 5a and 5b are positioned horizontally with respect to the printed circuit board on which the transformer body is mounted, and the flux generated from the magnetic materials 5a and 5b is horizontal. Direction. As a result, the leakage flux 18 also occurs horizontally with respect to the printed circuit board. Therefore, L, C,
When components such as R and semiconductor are attached, the leakage flux 18 affects the circuit and is one of the causes of noise. As a countermeasure, a method of separating those parts from the transformer or arranging them at a position where the influence of leakage flux is small is adopted. Therefore, there are problems that the area of the printed circuit board is increased, the transformer is separated, and the circuit is restricted. Further, safety standards are established for such transformers according to the electronic devices used, for example, UL560 is applied to a washing machine and UL923 is applied to a microwave oven, and primary-different poles, primary-secondary, primary-magnetic. The insulation distance between materials and the like, the insulation thickness of each material, etc. are defined.
The insulating structure of this transformer will be described with reference to FIG. The insulation distance between the back 4a of the primary coil 4 and the secondary coil 3 made of a substantially U-shaped conductor is a spatial dimension of A + B, and the insulation distance between the back 4a of the primary coil 4 and the magnetic material 5b is C.
The space dimension is + D. In order to secure these dimensions above the specified values, the position of the back portion 4a of the primary coil 4 is increased in the outer side X direction of the upper end collar 7 and is increased in the upper Z direction of the upper end collar 7 to secure the insulation distance. It was a structure that does. Therefore, the height dimension E of the upper end collar 7a of the bobbin is large, and the dimension F of the upper end collar 7 in the lateral outside X direction needs to be large. As a result, the size of the transformer becomes large, which leads to an increase in cost of the bobbin and the magnetic material, and the mounting area on the printed circuit board becomes large. Further, the insulation distance is greatly varied due to variations in the height position of the back portion 4a of the primary coil 4, and in order to guarantee the quality, a severe visual appearance inspection is required in the inspection process, which is a major reason why the inspection cannot be automated. In addition, in terms of electrical performance, the smaller the distance between the primary coil 4 and the secondary coil 3, the denser the coupling, and the better the response performance to a minute current, but as described above. In order to clear the safety standard, the specified insulation distance must be secured, and as a result, the distance between the primary coil 4 and the secondary coil 3 becomes large and the coupling becomes loose coupling, and the electrical performance such as response performance deteriorates. There was a drawback.

Next, a vertical structure in which a metal pin terminal 9 and a primary coil 4 having the same shape as that of the horizontal structure shown in FIG. 4 are attached to the side surface of the bobbin collar, and a magnetic material is vertically inserted into the transformer mounting surface. The current transformer will be described with reference to FIG.

The insulating structure between the primary coil 4 and the secondary coil 3 or between the primary coil 4 and the magnetic materials 5a and 5b is exactly the same as that shown in FIG. The lead wire 22 of the secondary coil 3 is connected so that the leakage flux 18 generated from the magnetic materials 5a and 5b intersects with the printed circuit board so that the leakage flux 18 generated from the magnetic materials 5a and 5b crosses the printed circuit board. The metal pin terminal 9 is planted on the side surface of the upper flange 7 in the same direction as the insertion direction of the magnetic material 5b, and further, the lead lead-out groove 10 through which the lead lead-out wire 22 of the secondary coil 3 passes is attached to the back portion 4a of the coil 4. A pair is provided sandwiching them. The primary coil 4 has a substantially U-shaped conductor 4b having a thick wire diameter.
Inserted into the pair of holes 19 penetrating the lower end collar 6, and further penetrating it, the tip 4b 'of the primary coil 4 protruding from the lower end collar 6
To form. Next, the tip 4b 'is bent at a right angle to the outside of the lower flange 6 and in the inserting direction of the magnetic materials 5b, 5a to form the terminal of the primary coil 4 attached to the printed board. As described above, the current transformer has a vertical structure in which the magnetic material is positioned perpendicular to the printed circuit board. However, since a large current is passed through the primary coil 4, it is generally 1.2.
Wire diameters of ~ 1.5 have been used. When the projecting tip 4b 'is bent at a right angle by penetrating the holes 19 of the lower ends of the bobbins 7 and 6, the bending stress is large, so that the bending fulcrum portion of the bobbin and the primary coil 4b' receives stress, and the bobbin moves. Even if it is broken or bent at a right angle due to the elasticity of the primary coil 4b 'itself, it has a drawback that it is restored and the dimensional accuracy is not obtained. Further, the insulating structure of the secondary coil 3 and the primary coil 4 will be described with reference to FIG. 9 as seen from the pin terminal side of FIG. 8. The secondary coil 3 passed through the lead lead-out groove provided in the upper flange 7 is shown. Lead lead wire 22 and primary coil 4
The distance of the back portion 4a is the value of the creepage distance of a + b + c 'through the wall 10' of the drawing groove 10. Assuming that the size of the SS-19 iron core applied to the Electronic Machinery Industry Standard, the outer diameter dimension is 19.0 mm, B is 5.0 mm, and C is 4.5 mm. The proper wall thickness that can be molded is 0.7 mm, and bobbin and magnetic material 5
The clearance between the a and 5b is 0.2 mm, and the clearance is 0.2 mm. The wire diameter of the primary coil 4 is 1.2 mm.
In the case of, the dimension of the lead withdrawing groove 10 provided in the upper end flange 7 is ha (e + h + t + li + dimensional tolerance),
4.5- (1.2 + 0.7 + 0.2 + 0.2 + 0.5)
= 1.7 mm. Therefore, the size is n = e + d + b. In addition, since the thickness b of the insulation thickness between the primary coil 4a and the lead wire 22 of the secondary coil 3 is 0.8 mm in the case of UL923, the rest is 1.7-0.8 = 0.
The dimension of e + d must be secured at 9 mm. Therefore, with an outer diameter dimension of 19 mm of the magnetic material 5b, such a current transformer conforming to the standard becomes practically impossible, and in order to clear this standard, the dimension of the rank one rank higher is 24 mm.
It is necessary to use the above-mentioned SS-24 type magnetic material. As a result, the outer diameter of the iron core is increased by 5 mm, the current transformer is enlarged, magnetic materials, bobbins, etc. are increased, and not only the cost of parts is increased, but also the mounting area is increased and the height is also increased. Has the drawback of.

As described above, the current transformer having the vertical structure as shown in FIG. 8 is not practically used because it has many drawbacks although it can be considered on a desk.

Next, a vertical type current transformer as shown in FIG. 6 will be described. The magnetic materials 5a and 5b are positioned perpendicular to the printed circuit board, which is the mounting surface of the transformer, and
The leakage flux 18 generated from a and 5b is in a direction perpendicular to the printed circuit board. This structure is provided as a measure for reducing the influence on the leakage flux of the current transformer of the horizontal structure described above. 7th
The insulating structure will be described with reference to the sectional views of the drawings. As described above, the insulation distance is defined by the standard depending on the equipment used, the insulation distance between the back surface 4a of the primary coil 4 and the magnetic material 5b is A + D, and the insulation distance between the primary coil 4a and the secondary coil 3 is The dimensions are A + B + C. Further, the insulation distance between the primary coil 4 and the secondary coil 3 protruding from the lower surface of the lower end flange 6 of the bobbin is G + H.

The winding height I of the secondary coil 3 is necessary to satisfy only the electrical performance, but in order to clear the safety standard, the prescribed dimensions must be required for the parts described above. As a result, it is necessary to increase the X-direction dimension F and the Z-direction dimension E of the bobbin upper end flange 7.

Also, the height dimension Ea of the lower end collar 6 of the bobbin must be increased in order to clear the safety standard. As a result, the dimension of the current transformer in the lateral direction or the height direction becomes large, and the bobbin and the magnetic material become large. This leads to an increase in cost and increases the mounting area on the printed circuit board.

Further, the primary coil 4 is outserted to the bobbin molded product, and the height position of the back portion 4a easily varies in the Z direction due to the step of inserting it into the hole 19, and as a result, the insulation distance A
Since + D or A + B + C will vary, it is necessary to perform a severe visual inspection in the inspection process for guaranteeing quality. Therefore, it has many drawbacks such as difficulty in automation of inspection and high cost.

As mentioned above, not only the external shape of the current transformer itself becomes large and the cost increases, but also the mounting area on the user printed circuit board increases, and the height dimension also becomes large, and further automation of inspection is difficult, resulting in quality and productivity. ，
It had many drawbacks in terms of cost.

Means for Solving the Problems The technical means of the present invention for solving the above problems separates a bobbin into an upper bobbin for a secondary coil and a lower bobbin for a primary coil, and the lower bobbin penetrates a magnetic material in the center. It is a flat plastic molded product with a hole, and several metal pin terminals to which the lead wire of the secondary coil is connected are planted on one side of the lower flange that faces each other through the hole for inserting the magnetic material on the lower surface. On the opposite side, the upper surface is substantially U-shaped, and the tip of both ends is a concave portion into which a primary coil made of a conductor bent downward at a right angle fits and a substantially U-shaped tip bent downward. The structure is provided with two holes through which the primary coil of the substantially U-shaped conductor is inserted and fitted into the recess and the hole of the lower bobbin to complete the assembled bobbin of the primary coil. Plastic that penetrates and winds a secondary coil around the outer circumference Has a tubular portion made of a molded product, and an upper end flange and a lower end flange are provided at the upper and lower ends of the tubular portion, and the bottom surface of the lower end flange is fitted in the center of the concave portion of the lower bobbin and is approximately U. An upper bobbin that holds a letter-shaped conductor and is provided with a substantially E-shaped projection that sandwiches the recess of the lower bobbin from both sides is fitted and fixed to the lower bobbin.

Operation The operation of this technical means is such that the primary coil made of a conductor having a substantially U-shape and the center of both of the distal ends of the legs bent downward at a right angle is inserted and fitted into the lower bobbin having the hole for penetrating the recess, and further the lower bobbin. The upper bobbin, which has a projection for pressing the primary coil made of the above-mentioned U-shaped conductor, is fitted into a recess provided on the upper surface of the lower end of the collar, and is fixed to the transformer mounting surface. The magnetic material is positioned vertically with respect to a certain printed circuit board, and the leakage flux also intersects with the printed circuit board. In addition, the substantially U-shaped primary coil is sandwiched between the lower bobbin and the upper bobbin in a sandwich shape, and the projection of the upper bobbin fits in the recess of the lower bobbin, so that the insulation distance between the primary coil and the secondary coil is plastic-insulated. It is a structure that clears the standard by ensuring the creepage distance.

Example One example of the present invention will be described below.

First, the structure of the bobbin will be described with reference to FIG. A plate-shaped lower bobbin 1 made of a plastic molded product is provided with a hole 16 for penetrating a magnetic material in the center, and a primary coil 4 made of a conductor having a substantially U shape and bent downward at right angles at the centers of both tip legs. A recess 8 to be fitted is provided, and the primary coil 4 is also provided.
A hole 19 is provided through which the front and rear legs are inserted and penetrated. Further, a step 20 is provided in the iron core insertion hole 16, a pair of lower end flanges 6a and 6b are provided on the lower surface of the lower bobbin 1 through the iron core insertion hole 16, and one of the lower end flanges 6a has several metal pin terminals. 9 have been planted. Further, an engaging step 21 to which the upper bobbin 2 is fixed is provided on the side surfaces of the lower end flanges 6a and 6b. In the hole 19 of such lower bobbin 1, the primary coil 4
Insert the tips of both legs and store them in the recesses 8 while gradually pushing in. When pushed all the way in, the tip of the primary coil 4 projects from the lower surface of the lower end flange 6b by a specified dimension. Thus, the assembly process of the primary coil 4 is completed. Next, the upper bobbin 2 will be described. A hole 16a for inserting a magnetic material is provided at the center, a cylindrical portion 14 made of a plastic molded product is provided on the outer periphery, and an upper end flange 7 and a lower end flange 6 are provided at the upper and lower ends thereof, respectively. In addition, a pair of lead-out grooves 10 and 10a are provided on the side surface of the lower end flange 6 via a magnetic material, and the projecting portions 1 that come into contact with the engaging step 21 of the lower bobbin 1 are formed on both end side surfaces thereof.
2 is provided. Further, on the lower surface of the lower end collar 6, a protrusion 11a that enters the step 20 provided in the magnetic material insertion hole 16 of the lower bobbin 1,
The step 20a provided on the lower end collar 6a is provided with a protrusion 11c having a structure to be fitted therein, and further provided with a protrusion 11b having a structure for pressing the primary coil 4 housed in the recess 8 of the lower bobbin 1. The upper bobbin 2 having the above-described structure is fitted onto the lower bobbin 1 on which the primary coil 4 has been assembled, from above, and the convex portion 12 of the upper bobbin 2 is pushed into the engaging step 21 of the lower bobbin 1 to fix the upper bobbin. 2 and the lower bobbin 1 are integrated.

Next, the step of winding the secondary coil will be described with reference to FIG. 2A, which is a side sectional view of the transformer of the present invention. Upper bobbin 2
A predetermined number of turns are wound around the cylindrical portion 14 with a predetermined wire diameter, and the lead 15 is wound and connected to the base 15 of a predetermined metal pin terminal 9 provided on the lower end flange 6a of the lower bobbin 1.

Further, the metal pin terminal 9 and the lead lead wire 22 are joined by soldering by solder dipping or the like. After that, as shown in FIG. 1, the magnetic material 5 is inserted into the magnetic material insertion hole 16a to form a closed magnetic path to complete the current transformer. The magnetic material 5 is applied to the E type, EI type, and EE type, and the insertion method may be either alternating insertion or butt insertion.

Next, the insulating structure will be described with reference to FIGS. 2A and 2B, which are sectional views of the current transformer of the present invention. FIG. 2A shows a sectional view as seen from the side. The insulation between the primary coil 4 and the secondary coil 3 is completely separated by the lower end collar 6 which is a plastic molding of the upper bobbin 2. Also, the insulation distance between the lead lead wire 22 of the secondary coil 3 and the primary coil 4 is the value of the creepage distance J because it is shielded by the wall thickness 10 'of the bottom of the lead lead-out groove made of the plastic molding of the upper bobbin 2. .

Further, the insulating structure of the primary coil 4 and the magnetic material 5 has a structure in which the projection 11a of the upper bobbin 2 fits into the step 16 provided on the lower bobbin 1, and the insulating distance is K + M + L. Further, the insulation distance between the primary coil 4a protruding through the hole 19 of the lower bobbin 1 and the magnetic material 5 is a creeping distance dimension of O + N.

Next, the insulating structure viewed from the front of the current transformer will be described with reference to FIG. 2B. The primary coil 4 and the secondary coil 3 are completely separated and shielded by a lower end collar 6 made of a plastic molded product of the upper bobbin 2, and the thickness of the lower end collar 6 has a specified insulation thickness. Can be cleared. Further, the insulating structure of the primary coil 4 and the magnetic material 5 is such that the primary coil 4 fits in the middle portion of the recess 8 provided in the lower bobbin 1 and is located in the middle portion.
Is pressed by the projection 11b provided on the lower end collar 6 of the upper bobbin 2, and both ends are sandwiched by the projection 11c and the projection 11a. The insulation distance between the middle leg 5a of the magnetic material 5 and the primary coil 4 is O + P + R. The insulation distance between the back portion 5b of the magnetic material 5 and the primary coil 4 is Q + T + S.

As described above, according to the present invention, the primary coil 4 is sandwiched between the lower bobbin 1 and the upper bobbin 2, and the recess 8 of the lower bobbin 1 and the protrusion 11 of the upper bobbin 1 are fitted and fitted to each other to form the primary coil 4 and the secondary coil 4. This is a structure in which the insulation distance between the secondary coil 3 and the primary coil 4 and the magnetic material 5 is secured by the creepage distance.
Further, the current transformer body of the present invention has a vertical structure as shown in FIG. 1, the magnetic material 5 is positioned in the direction perpendicular to the printed circuit board surface, and the leakage flux 18 is also generated in the direction perpendicular to the printed circuit board. Become. Therefore, in the conventional horizontal type current transformer shown in FIG. 4, the leakage flux generated from the current transformer has a problem that the electronic components mounted near the current transformer are affected and noise is generated. The present invention can reduce the influence of leakage flux by adopting the vertical structure. There is a conventional type current transformer having a vertical structure shown in FIG. 6 in which the influence on the leakage flux is reduced by the same structure, but a comparison will be made between the present invention and the insulating structure. FIG. 2 is a sectional view of the current transformer of the present invention, and FIG.
Explaining with a sectional view of the drawing, the insulation distance between the magnetic material 5 and the primary coil 4 is A + D in the conventional current transformer.
And Q + S + T in the current transformer of the present invention. In order to comply with the safety standard, the insulation distance between the primary coil and the secondary coil and between the primary coil and the magnetic material should be 3.2.
When the insulation thickness is 0.7 mm and the insulation thickness is 0.7 mm, in the conventional example shown in FIG. 7, 3.2 = A + D = A + 0.7, and the value of A is 2.5 mm. In FIG. 2B of the present invention, when T = 0.7 and Q = 1.0, 3.2 = Q + S + T = 1.0 + S + 0.7 and S = 1.5 mm. That is, the dimension of the height E of the upper end collar 7 of the conventional example is 2.5 mm because the space distance A is required.
Must be high. As a result, the height E of the upper flange 7 increases, and the height of the bobbin and the height of the magnetic material also increase by the dimension of the spatial distance A. However, in the current transformer of the present invention, as shown in FIG. 2B, the primary coil 4 made of a substantially U-shaped conductor is formed in the recess 8 and the step 20 of the lower bobbin 1.
The upper bobbin 2 with the protrusions 11a, 1 sandwiched between them.
With the structure in which 1b and 11c are fitted together, the dimension is secured by the creepage distance of the plastic molded product, and as a result, the lower end flange 6 of the upper bobbin 2 to which the primary coil 4 is attached
The height dimension U can be made smaller than that of the conventional example. That is, comparing the conventional example and the transformer of the present invention in the case where the winding space V of the secondary coil 3 of the iron core cross-sectional area and the iron core window size are set to the same size and the electric capacities are made the same, the current transformer of the present invention is compared. The height for forming the primary and secondary coil portions 4 and 3 is U + V. By reducing U, it is possible to reduce the height U + V of the coil portion, which in turn reduces the window dimension of the magnetic material. It is also possible to reduce the height of the current transformer. On the other hand, in the conventional current transformer shown in FIG. 7, the portion corresponding to U in FIG. 2B of the present invention is located at the bottom and has substantially the same size. However, the primary coil 4
Since the magnetic material 5b is close to the upper part of a, the insulation distance is A + D, and in order to secure the specified dimension, the dimension of A must be set large as described above. Therefore, the height E of the bobbin and the height of the magnetic material 5b are increased, and the height of the current transformer itself is also increased.

Next, the insulation structure of the primary coil 4 and the secondary coil 3 will be described with reference to FIG. 2B which is a cross-sectional view of the transformer of the present invention and FIG. 7 which is a cross-sectional view of the conventional transformer.

In the transformer shown in FIG. 2B of the present invention, the primary coil 4 and the secondary coil 3 are completely separated by the lower end flange 6 made of a plastic molded product of the upper bobbin 2. What is needed is the thickness of the plastic of the lower end collar 6, so that the distance between the primary coil 4 and the secondary coil 3 is Q + material thickness.

On the other hand, in the conventional current transformer, the insulating structure of the primary coil 4a and the secondary coil 3 is arranged in parallel via the insulating plate 13. Due to the structure in which the upper part is opened, the insulation distance is A + B + C. Secondary coil 3
Considering the deviation due to the variation of the winding state, the dimension of C cannot be included in the calculation due to the problem of quality assurance.
Therefore, the guaranteed insulation distance is the creepage distance of A + B. The distance between the primary coil 4 protruding from the lower end flange 6 of the bobbin and the secondary coil 3 is G + H. As described above, considering deviation due to variations in the winding state of the secondary coil 3,
The height Ea of the lower end collar 6 of the bobbin must be large
Must be increased. As mentioned above, the upper flange 7
Since the height E of the current transformer is also increased, the height of the current transformer is further increased, and there is a problem that the set itself is increased in mounting the set. Also, for those that are too high for practical use and cannot be used, it is necessary to lower the height Ea of the lower end collar 6,
As the method, the dimension of the creepage distance G between the primary coil 4 and the secondary coil 3 is set to be large. As a result, the size of the insulating plate 13 provided on the upper flange 7 increases, and the distance between the primary coil 4 and the secondary coil 3 increases. As described above, the distance between the primary coil 4 and the secondary coil 3 of the present invention is smaller than that of the present invention, and the coupling becomes a tight coupling.
The response performance to a minute current can also be improved significantly.

As described above, according to the present invention, the current transformer has the vertical structure in which the magnetic material is attached and is inserted vertically to the printed circuit board, and the primary coil and the secondary coil are formed separately. , A structure in which they are integrated by fitting them to each other, that is, a recessed portion, a stepped hole portion, etc. are provided on the upper surface of a plate-shaped lower bobbin forming the primary coil, and a substantially U-shaped tip portion is bent downward. The primary coil consisting of a bent conductor is housed in the recess of the lower bobbin while penetrating the hole, and then the upper bobbin having a protrusion on the lower end collar that fits into the recess of the lower bobbin It has a structure in which the lower bobbin formed with a coil is inserted, fitted and fixed to be integrated. Since the so-called substantially U-shaped primary coil is sandwiched between the upper bobbin and the lower bobbin made of a plastic molded product in a sandwich form to be fixed, the primary coil and the secondary coil,
The height of the bobbin and the height of the magnetic material are reduced by the method of structurally fitting the insulation of the primary coil and the magnetic material to the concave portion of the lower bobbin and the protrusion of the upper bobbin to the step to secure the creepage distance of the plastic. Not only the cost of parts can be reduced, but also the height of the current transformer itself can be reduced. In addition, since the primary coil is sandwiched between the upper bobbin and the lower bobbin and fixed, the insulation distance can be structurally guaranteed, and the primary coil floats and the secondary coil is secured to ensure the insulation distance as in the conventional example. It is not necessary to visually inspect the winding wire deviation, etc., and the inspection can be automated easily. Furthermore, the structure in which the primary coil and the secondary coil are insulated by the plastic molding bobbin enables the distance between the coils to be reduced, the coupling becomes dense, and the response performance to a minute current is significantly improved. .

Further, the current transformer of the present invention has a vertical structure in which a magnetic material is attached and is positioned perpendicular to the printed circuit board, and the influence of leakage flux is small with respect to other electronic components mounted near the current transformer, resulting in less noise. Occurrence can be reduced. As a result, it is not necessary to keep the distance between the current transformer and other electronic components, and high density and high packaging can be realized. As described above, the present invention can be miniaturized in shape and can be greatly improved in terms of quality, cost, and productivity.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a current transformer of the present invention (hereinafter referred to as a transformer), FIG. 2A is a sectional view of the transformer of the present invention seen from a side surface, and FIG. 2B is a front view of the transformer of the present invention. FIG. 3 is a perspective view of a component of a transformer of the present invention, FIG. 4 is a perspective view of an embodiment of a conventional horizontal type current transformer, and FIG. 5 is a perspective view of a conventional horizontal type current transformer. FIG. 6 is a perspective view of an embodiment of a conventional vertical type current transformer, FIG. 7 is a side view of a conventional vertical type current transformer, and FIG. 8 is a conventional side view. Horizontal structure current transformer No. 4
FIG. 9 is a perspective view of a transformer having a vertical structure in which the pin position is changed, and FIG. 9 is an enlarged view of the current transformer of FIG. 8 viewed from below. 1 ... Lower bobbin, 2 ... Upper bobbin, 3 ... Secondary coil,
4 ... Primary coil, 5 ... Magnetic material, 6 ... Lower flange, 7 ...
… Top flange, 8 …… recess, 9 …… metal pin terminal, 10 ……
Lead lead-out groove, 11 ... Protrusion, 12 ... Protrusion, 13 ...
... Insulation plate, 14 ... Cylindrical part, 15 ... Root, 16 ... Magnetic material insertion hole, 17 ... Insulation tape, 18 ... Leakage flux, 19 ... Hole, 20 ... Step, 21 ... Combined step, 22 ... Lead lead wire.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazushige Ishikawa 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Hisanori Tanigaki, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Matsuo Imai 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (1)

[Claims] 1. A flat plastic molded product having a hole through which a magnetic material penetrates in the center, and several metal pin terminals are planted on one lower end flange facing the hole penetrating the magnetic material on the lower surface thereof. On the upper surface of the opposite side, a concave portion into which a primary coil made of a thick conductor having a substantially U-shaped tip center of both legs is bent downward at a right angle is fitted, and a substantially U-shaped portion is bent downward. A cylindrical portion made of a plastic molded product, in which the above-mentioned U-shaped conductor is fitted to a lower bobbin provided with a hole through which the tip penetrates, a magnetic material is further penetrated in the center, and a secondary coil is wound around the outer circumference, An upper end flange and a lower end flange are provided at the upper and lower ends of the tubular portion, and a substantially U-shaped conductor fitted in the center of the recess of the lower bobbin is pressed on the lower surface of the lower end flange and the recess of the lower bobbin is formed. The upper bobbin, which has a roughly E-shaped protrusion that is sandwiched from both sides, Fixedly fitted the current transformer to the lower bobbin.