JPS6117229B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flyback transformer that supplies high voltage to a cathode ray tube anode of a television receiver or the like.

Flyback transformers used in television receivers, especially color television receivers, are required to generate a high voltage with a good voltage fluctuation rate.

In order to meet this requirement, the number of turns of the high-voltage coil of the flyback transformer is increased and higher harmonics are optimally superimposed on the retrace pulse, but increasing the number of turns inevitably increases the distributed capacitance. It becomes difficult to obtain high-order harmonic tuning. Therefore, the first
As shown in the figure, a high voltage coil 3 magnetically coupled to a low voltage coil (horizontal output coil) 2 of a flyback transformer 1 is divided into a plurality of segmented coils 6, 7, 8 via a plurality of diodes 4, 5. Therefore, the distributed capacitance of the high voltage coil 3 is reduced.

Furthermore, when a bipotential cathode ray tube is used as a receiver, a DC voltage of several kilovolts is required for the focus electrode. An intermediate voltage is taken from the cathode of the diode 4 that rectifies the voltage of the dividing coil 6, and divided by the variable resistor 9 to a predetermined focus voltage Vf.
I am getting . However, if the intermediate voltage is too high, an excessively high voltage will be applied to the resistor 9, so a resistor 9 with a high withstand voltage and voltage division ratio will be required, making it expensive and requiring special consideration for its mounting position. It was necessary.

By the way, the high voltage coil 3 is usually a second coil from the viewpoint of ease of winding and reduction of distributed capacitance.
As shown in the figure, the wire is wound on a split bobbin 10 having a large number of winding grooves. In the winding groove 11 of the split bobbin 10, the above-mentioned segmented coils 6, 7, and 8 and diodes 4 and 5 connected in series between the segmented coils are alternately accommodated.

Further, in order to improve the magnetic coupling between the low voltage coil 2 and the high voltage coil 3, flyback transformers often have a structure in which the high voltage coil 3 is placed over the low voltage coil 2 mounted on the core 12. However, if the high-voltage coil 3 is wound around a divided bobbin 10, it is possible to reduce the leakage inductance and distributed capacitance, but as shown in FIG. Since there are winding grooves 11 where the sectional coils are wound, and conductors are wound closely in the winding grooves 11 where the segmented coils are wound, the degree of coupling between the low-voltage coil 2 and the high-voltage coil 3 is not the best. However, if the best high-order harmonic tuning cannot be obtained, it is difficult to obtain a good voltage fluctuation rate.

In order to solve this drawback, a structure in which the high-voltage coil is wound in a single layer with equal winding width and laminated is used. However, in such a high-voltage coil, each winding layer is wound at the same pitch and with the same number of turns, and a variable resistor 9 as shown in Fig. 1 is required to extract the focus voltage Vf. Ta.

The present invention has been made in order to improve the above-mentioned drawbacks, and provides a flyback transformer in which a high voltage coil is wound in a flat winding manner and has a good voltage fluctuation rate.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In FIG. 3, the flyback transformer 13 includes a core 14, a low voltage coil 15 attached to the core 14, and a high voltage coil 16 disposed on the coil 15.
is divided into a plurality of segmented coils 17, 18, 19, and diodes 20, 21 are connected in series between the segmented coils. The other end of the first stage segment coil 17 is grounded, and the other end of the last stage segment coil 19 provides a rectified high voltage to the cathode ray tube anode via a diode 22. Further, when a focus voltage is required, an intermediate terminal 23 is provided between the diode 20 and the next-stage section coil 18 to directly draw out the focus voltage Vf.

FIG. 4 shows a schematic structure of the flyback transformer of the present invention. The low-voltage coil 15 is a cylindrical low-pressure bobbin 2 partitioned into a plurality of pieces by a flange-like projecting wall 24.
5. The wire is wound flatly and widely. A plurality of terminal portions 26 extending in the radial direction are provided at one end of the bobbin 25, and a terminal pin 27 is provided in the terminal portion 26 in the axial direction.
is planted, and the ground side lead wire of the high voltage coil 16,
The lead wire of the low voltage coil and the lead wire of a tertiary coil (not shown) (coil for AGC, heater, etc.) are connected respectively.

The high-voltage coil 16 is made of an interlayer insulating material such as an interlayer bobbin formed into a hollow cylindrical shape with different radii using a polycarbonate resin, a glass-filled polyester resin, or a resin having a relatively small coefficient of linear expansion, or a resin film 28, 29 as an interlayer paper. 30 is used to flat wind the wire. That is, each section coil 17, 18, 19 of the high-voltage coil 16 has the same winding width W for one interlayer insulating member 28, 29, 30, even if the number of turns is different, as shown in FIG. The coils are wound in layers at equal pitches and in the same winding direction for each segmented coil, and are successively stacked on top of the first stage segmented coil 17 by the number of segmented coils. In this case, the winding start S and winding end e of each segmented coil are arranged on planes P ₁ and P ₂ perpendicular to the axis of the coil, respectively.

Further, the winding width of the low voltage coil 15 is also wound to have the same width as the winding width w of the segmented coil, and the winding start and winding end thereof are configured to be located on planes P ₁ and P ₂ similarly to the segmented coil. .

Further, as shown in FIG. 5, in the high voltage coil 16, the winding start s and winding end e of each segmented coil 17, 18, 19 are aligned on the same side in accordance with the low voltage coil 15, so that the potential gradient is lower than that of the low voltage coil 15. is set to be in the same direction as By arranging in this way, the distributed capacitance of each winding of each section coil 17, 18, 19 with respect to each winding of low voltage coil 15 is made equal, and the output characteristics of high voltage coil 16 are improved.

In a flyback transformer that requires a focus voltage, the number of turns of the first-stage section coil 17 is set to a predetermined number of turns relative to the number of turns of the other section coils 18 and 19 in order to directly derive the required focus voltage Vf. Selected many times. That is, depending on the focus voltage Vf to be taken out, the segment coil 17 is wound more or less than the segment coils 18 and 19. For example, if the segmented coils 18 and 19 are wound around the interlayer insulating members 29 and 30 using ultrafine wire with a diameter of 30 to 50μ, with 840 turns of equal width w,
The segmented coil 17 is wound with 780 turns of the same width w using conducting wires of the same wire diameter and widening the winding pitch.

In the above configuration, when changing the focus voltage Vf, it is done by changing the number of turns of the first stage segmental coil 17. Even in this case, the winding width is determined to be the same as the winding width w of the other segmented coils 18 and 19, and the direction of potential gradient is also matched to that of the low voltage coil 15.

In addition, if the voltage obtained from the intermediate terminal 23 is higher than the actual focus voltage, a variable resistor is connected as in the conventional method, but since the difference between the required focus voltage and the intermediate voltage is small, an inexpensive alternative can be used. can be done with a simple resistor.

Note that the bobbin around which the low-voltage coil 15 is wound may have a simple hollow cylindrical shape.

As mentioned above, the flyback transformer of the present invention has a low-voltage coil and a high-voltage coil placed one on top of the other, the high-voltage coil is divided into a plurality of segmented coils, and the segments are connected in series with diodes, and each segmented coil is Since the wires are wound in a flat single layer and the wires are wound with the same width even if the number of turns is different, the following effects can be obtained.

(1) The low-voltage coil and high-voltage coil are tightly coupled with low leakage inductance, so even if high-order harmonic tuning cannot be obtained, the high-voltage output of the high-voltage coil can always be maintained at a favorable voltage fluctuation rate in response to load fluctuations. A high-performance flyback transformer can be obtained.

(2) Since the high-voltage coil is divided by diodes, the interlayer withstand voltage is low, and the high-voltage coil can be divided into a wide range of plain-wound coils and the number of turns per layer can be increased to obtain a desired high-voltage output, so flyback is possible. The transformer can be made smaller.

(3) When obtaining an intermediate voltage, even if the number of turns of the section coil placed immediately above the low voltage coil is smaller than that of other section coils, the coils are wound with the same width as the other section coils, so the low voltage The magnetic coupling between the coil and the high-voltage coil can be optimized, and an intermediate voltage can be obtained without adversely affecting the voltage fluctuation rate.

(4) Since the intermediate voltage can be directly brought to a voltage close to the focus voltage by simply changing the number of turns of the first segmental coil, there is no need for the conventional expensive variable resistor, and the flyback transformer can be made cheaper. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a wiring diagram of a conventional flyback transformer, Fig. 2 is a schematic sectional view of a conventional flyback transformer, Fig. 3 is a wiring diagram of a flyback transformer according to the present invention, and Fig. 4 is a wiring diagram of a flyback transformer according to the present invention. FIG. 5 is a schematic sectional view of the back transformer, and is an explanatory diagram showing the winding mode of the high voltage coil according to the present invention. In the figure, 15 is a low voltage coil, 16 is a high voltage coil,
17, 18, 19 are segmented coils, 20, 21, 2
2 is a diode, 23 is a focus terminal, 25 is a low voltage bobbin, and 28, 29, and 30 are interlayer insulation members.

Claims (1)

[Claims] 1 In a flyback transformer in which a rectifier diode is connected in series between a plurality of segmented coils obtained by dividing a high-voltage coil, each segmented coil is flat-wound and stacked, and placed on top of a low-voltage coil. The direction of the potential gradient of the segment coil is made to match the direction of the potential gradient of the low voltage coil, and even though the number of turns of the segment coil wound on the low voltage coil is different from the number of turns of the other segment coils, the above A flyback transformer characterized in that the winding width of each section coil is equal, and both ends of the low-voltage coil and each section coil are located substantially on two planes perpendicular to the coil axis.