JPH0726828Y2 - Trance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to improvement of a transformer such as a flyback transformer.

(Prior Art) Conventionally, a transformer is configured by winding a primary coil and a secondary coil around a core forming a closed magnetic circuit. For example, like the conventional flyback transformer shown in the schematic cross-sectional view of the main part of FIG. 6, the core 61 has two U-shaped (not shown) ferrite cores, one end of which is closely attached to the other end of which is the other end. By forming the gap portion 62 with a slight gap therebetween, a substantially rectangular closed magnetic circuit (not shown) is formed. A low-voltage bobbin 63 is arranged around the gap 62 and the core in the vicinity thereof, and the primary coil is arranged on the low-pressure bobbin 63.
64 is wound, and a secondary coil (not shown) is further wound thereon. The gap portion 62 provided in the closed magnetic circuit formed by the core 61 is for increasing the magnetic resistance in the magnetic circuit to prevent magnetic saturation.
By inserting the gap member 65 made of polyester into the inside of the 62, a predetermined interval is formed and maintained.

When an alternating current flows through the primary coil 64, a magnetic flux is generated in the core 61, the magnetic flux links with a secondary coil (not shown), and a change in magnetic flux due to a change in current flowing through the primary coil 64 causes an electromotive force in the secondary coil. Induce.

(Problems to be solved by the invention) By the way, the magnetic flux generated in the core 61 leaks from the one end surface of the gap portion 62 to the outside of the core 61 as a leakage magnetic flux φ ′, and constitutes the primary coil 64 and a secondary coil (not shown). Through the copper wire to the other end of the gap 62. The change in the leakage flux φ'through the copper wire causes a back electromotive force in the copper wire, which creates an eddy current in the copper wire. The eddy current flowing in the copper wire was consumed as Joule heat, causing local heat generation in the vicinity of the gap 62. For this reason, the peripheral parts are defective due to the temperature rise. Further, in the case of a high-voltage transformer, it was necessary to use a type of insulation having a high allowable maximum temperature.

The problem to be solved by this invention lies in how to reduce the leakage flux φ ′ from the gap portion of the core to reduce the eddy current, and to control the leakage flux.

(Means for Solving the Problems) In order to solve the above problems, the transformer according to the present invention is
A cylinder having a high magnetic permeability, which has a gap in a part of a core forming a closed magnetic path, and is formed by winding a coil around the gap of the core. The gap is formed by joining two hollow semicircular ends. It is formed by a container having a member housed therein.

(Operation) In the transformer configured as described above, when an AC voltage is applied to the coil to cause a current to flow, a magnetic flux is generated inside the core,
A magnetic flux is generated from one end of the gap portion to the other end. A large portion of the magnetic flux is passed through the high-permeability member inserted in the gap portion, and the leakage magnetic flux leaking from the gap portion and passing through the copper wire is reduced to reduce the eddy current generated in the copper wire. The leakage magnetic flux from the gap portion can be controlled not only by the thickness of the container and the thickness of the two upper and lower surfaces, but also by the area of the high-permeability columnar member accommodated therein.

Embodiment An embodiment of the transformer according to the present invention will be described below with reference to the drawings. FIG. 1 is a schematic sectional view of a main part of a premise example of the present invention. In FIG. 1, a core 11 comprises two U-shaped ferrite cores, one end portion of which is closely adhered to each other, and a gap portion 12 having a slight gap is formed between the other end portions thereof. It forms a closed magnetic circuit. A low voltage bobbin 13 is arranged around the gap portion 12 and the core 11 in the vicinity thereof, a primary coil 14 is wound on the low pressure bobbin 13, and a secondary coil (not shown) is further wound thereon. Inside the gap portion 12 of the core 11, a gap member 15 made of plastic such as polyester and a member 16 having high magnetic permeability sandwiched therebetween are inserted. Two gap members 15 and a ferromagnetic member between them
The total thickness with 16 becomes equal to the interval of the gap part 12,
The gap portion 12 is formed and held at a predetermined interval. And
The thickness of each of the gap member 15 and the high magnetic permeability member 16 is determined so that the magnetic resistance of the member 16 has a predetermined value. As the high magnetic permeability member 16, for example, ferrite, which is a ferromagnetic material similar to the core 11, is used.

When an alternating current flows through the primary coil 14, a magnetic flux φ is generated in the core 11 as shown in FIG. 2, the magnetic flux interlinks with a secondary coil (not shown), and the magnetic flux changes due to the change in the current flowing through the primary coil 14. Induce an electromotive force in the secondary coil. Meanwhile, the core
The magnetic flux φ generated in 11 is divided into one that goes to the member 16 having a high magnetic permeability in the gap portion 12 and one that leaks to the outside. That is, most of the magnetic flux φ goes out from one end face of the gap portion 12, passes through the upper gap member 15, is drawn into the member 16 having high magnetic permeability, passes through this, passes through the lower gap member 15, and passes through the gap portion. It goes into the other end of 12 and goes into the core 11. The remaining magnetic flux φ ′ leaks from one end of the gap portion 12 to the outside, is drawn into the high magnetic permeability member 16 and passes therethrough, leaks to the outside again from the end portion thereof, and enters the other end of the gap portion 12.
Therefore, the amount of the leakage magnetic flux φ ′ can be controlled by the magnetic permeability or the thickness of the high magnetic permeability member 16. At this time, the leakage magnetic flux φ ′ penetrates the primary coil 14 and the copper wire forming the secondary coil (not shown), and the change of the leakage magnetic flux φ ′ penetrating the copper wire causes a counter electromotive force in the copper wire. An eddy current is generated inside. However, the magnetic flux φ of the gap 12
Most of the magnetic flux passes through the member 16 having a high magnetic permeability, and the magnetic flux φ ′ leaking to the outside is small. Therefore, the eddy current flowing in the copper wire is much smaller than that described as the conventional technique, and it is possible to prevent local heat generation in the vicinity of the gap 12.

Based on the above description, an embodiment of the transformer according to the present invention will be described.

FIG. 3 is a view for explaining an embodiment of the present invention, and is a partially cutaway assembly perspective view of a member having a high magnetic permeability and a container accommodating the member. In FIG. 3, the member 163 having a high magnetic permeability is formed in the shape of a thin disk as in the case of FIG. 1, and is made of, for example, ferrite. The high magnetic permeability member 163 is housed in two hollow semicircular plastic containers 17. The container 17 is formed into a disc shape by accommodating the member 163 having high magnetic permeability and then joining the end faces with an adhesive. High permeability member 163 and container 17
The disc-shaped upper and lower surfaces of the container 17 integrated with are inserted so as to face the surface of the gap portion. Such integration facilitates handling and facilitates assembly of the transformer. Further, since the high magnetic permeability member 162 is integrally housed in the container 17, the leakage magnetic flux can be controlled. That is, the thickness of the member 163 having a high magnetic permeability is L1, the upper and lower areas of the disk shape are S1, the magnetic permeability is μ1, and the thickness of the container 17 is L1.
2, the area of the surface facing the gap is S2, the magnetic permeability is μ
2, the magnetic resistance Rm1 of the high magnetic permeability member 163 is Rm1 = L1 / μ1 · S1, and the magnetic resistance Rm2 of the portion where the container 17 overlaps the high magnetic permeability member 163.
Is Rm2 = (L2-L1) / μ2 · S1, the magnetic resistance R of the part where the container 17 does not overlap with the high magnetic permeability member 163.
m3 is Rm3 = L2 / μ2 · (S2-S1), and the combined magnetic resistance Rm of the gap formed by the container 17 accommodating the high magnetic permeability member 163 is 1 / Rm = 1 / (Rm1 + Rm2) It is given by + 1 / Rm3. The combined magnetic resistance Rm can also be determined by the thicknesses L1 and L2 of these portions and the area S2 of the high magnetic permeability member 163, and thus the amount of leakage magnetic flux can be controlled.

FIG. 4 is a sectional view for explaining another first reference example derived from the premise example of FIG. 1, and a member 164 having a high magnetic permeability similar to that of FIG. 1 is coated with plastic 154. It is a thing.

FIG. 5 is an exploded view of another second reference example derived from the premise example of FIG. In FIG. 5, low pressure bobbin 135
A support portion 18 is provided at a substantially central position of the core, that is, at a position where a gap portion of the core is formed when assembled, a high magnetic permeability member 165 is accommodated and supported in the low pressure bobbin 135, and a plastic sheet gap member is provided thereon. Overlaps 155.
One end of the core (not shown) comes into contact with the upper surface of the gap member 155, and the other end of the core comes into contact with the lower surface of the support portion 18. The gap interval is the gap member 155, the high magnetic permeability member 165 and the support portion. Determined by a total of 18 thicknesses. By doing so, the low-pressure bobbin can be handled in a state where the high-permeability member is housed, and even if the high-permeability member is added, it can be handled without being aware of it.

(Effect of the Invention) As described above, since the transformer of the present invention is configured as described above, it is possible to reduce the leakage magnetic flux from the gap portion and extremely reduce the eddy current. Therefore, it has various advantages as follows. That is, it is possible to reduce local heat generation in the gap portion due to the eddy current, prevent an increase in temperature, and reduce defective parts due to heat generation. Since the leakage magnetic flux becomes small, the magnetic flux density can be made small, and the core diameter can be made small in the range in which the magnetic flux density is not saturated, which gives a margin to the transformer design. Further, since the eddy current is small and the heat generation is small, the insulation type can be changed from the A type insulation to the Y type insulation.
Furthermore, since it can prevent the temperature rise, it is suitable for high inches.
FBT (Used for high definition and high image quality by obtaining a bright screen by increasing the image quality and applying voltage.)
However, it is possible with the conventional standard type with a small core diameter.
Become. Further, since the gap is formed by the container in which the two semi-circular hollow end portions are joined and the disc-shaped member having high magnetic permeability is housed inside, the amount of leakage magnetic flux can be controlled and at the same time easy. It has the advantages that it can be set between the cores, it is easy to handle, and the transformer can be easily assembled.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a main part of a premise example of the present invention, FIG. 2 is a view for explaining a distribution of magnetic flux, FIG. 3 is a partially broken assembly perspective view of an embodiment of the present invention, and FIG. Is a cross-sectional view of the first reference example,
FIG. 5 is an exploded view of the second reference example, and FIG. 6 is a schematic sectional view of a main part of a conventional flyback transformer. 11 ... Core, 12 ... Gap part, 13, 132 ... Low pressure bobbin, 14 ...
Primary coil, 15,153 ... Gap member, 16,162, 163 ... High magnetic permeability member, 17 ... Container, 18 ... Support part

Claims (1)

[Scope of utility model registration request] 1. A transformer having a gap in a part of a core forming a closed magnetic path and winding a coil around the gap of the core, wherein the gap joins two hollow semicircular ends. Then, the transformer is formed by a container having a disk-shaped member of high magnetic permeability contained therein.