JPH05258969A - High voltage transformer core - Google Patents

Abstract

PURPOSE:To set a core as small in size as possible and to obtain a transformer where a prescribed withstanding voltage is set between a pin and the core by a method wherein a yoke member provided with a slope which is tilted towards the end side wall of the yoke extending from a part of the yoke in contact with a terminal board is provided. CONSTITUTION:An E-type core 20 is provided with a center leg 21 flat in cross section at its center and side legs 22 and 23 arranged on the sides of the center leg 21. The roots of these three legs are joined together by a yoke 24. A slope 25, which is obliquely tilted towards the underside of the yoke 24 inn contact with terminal boards 9 and 10 extending from a midway point on the end side wall 26, is provided. By this setup, a core or a terminal board is not required to be larger than usual, and the same creeping distance with a conventional one can be kept between a core and a pin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core for a high voltage transformer, and more particularly to a core for a high voltage transformer with improved withstand voltage.

[0002]

2. Description of the Related Art Conventionally, a core formed by firing magnetic powder has been used for an interstage coupling transformer of an amplifier, a speaker transformer, etc., but with the recent development of electronic equipment,
The range of use of the core has expanded, and has expanded to the range of home appliances such as computers and their terminal devices. In addition, since the equipment in which the core is used tends to be downsized or flattened, the shape of the transformer using the core formed by firing the magnetic powder is also flattened.

8 to 10 are perspective views showing a conventional E-shaped ferrite core for a transformer, a bobbin, and a transformer assembled by using these. In FIG. 8, 1
Is an E-shaped core. The E-shaped core 1 has a flat cross section in the center, a central leg 2 around which a coil is wound, and side legs 3 and 4 are arranged on both sides of the central leg 2. The root of is connected to the central leg 2 by a yoke portion 5 connected in a T shape.

In FIG. 9, 6 is a bobbin body, and frame plates 7 and 8 are provided on both sides of the bobbin body. Terminal plates 9 and 10 are provided on the lower surfaces of the respective frame plates 7 and 8, and pins 11 and 12 for connecting the lead wires of the coil are attached to the terminal plates 9 and 10. A through hole 13 is provided at the center of the bobbin body 6. The assembly of this transformer will be described. First, the bobbin body 6
Make a predetermined winding on the
After being wound and connected to 2, two E-shaped cores 1 are prepared, and the respective central legs 2 are inserted from both ends of the through hole 13 of the bobbin main body 6 to assemble the transformer. FIG. 10 is a perspective view showing the transformer that has been assembled. In FIG. 10, reference numeral 14 denotes a coil wound around the bobbin main body 6.

[0005]

When the above transformer is used in, for example, a flash discharge emitter for photography, the secondary voltage of the transformer rises to the order of thousands of volts. Therefore, in order to improve the withstand voltage PV between the pins 11 and 12 and the core 1, the terminal boards 9 provided at both ends of the bobbin main body,
Increase the length of 10 in the longitudinal direction to obtain the desired withstand voltage PV
Was getting. Therefore, the length of the high-voltage transformer in the longitudinal direction becomes long, which causes an inconvenience that the movement is opposite to the purpose of downsizing the high-voltage transformer.

Therefore, it is an object of the present invention to provide a core for a high-voltage transformer which can miniaturize the core as much as possible and can obtain a predetermined withstand voltage between the pin and the core.

[0007]

In order to achieve the above object of the present invention, the present invention provides a central leg around which a coil is wound, and a yoke portion connected to the central leg in a T-shape. And a core for a high-voltage transformer having two side legs arranged at both ends of the yoke portion and parallel to the central leg from the end portions, which is one surface of the yoke portion and contacts the terminal plate. There is provided a core for a high voltage transformer, comprising a yoke member provided with an inclined portion that inclines toward the end side wall of the yoke portion.

[0008]

The function is to provide an inclined portion that is inclined from one portion of the yoke portion, which is in contact with the terminal plate, to the end side wall of the yoke portion,
Ensure sufficient creepage distance between core and pin. Also,
The inclined portion also serves as a reinforcing member for the core.

[0009]

An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of a core for a high voltage transformer according to the present invention. 1 and 2, reference numeral 20 denotes an E-shaped core. The E-shaped core 20 has a central leg 21 having a flat cross section in the center, and side legs 22 and 23 are arranged on both sides of the central leg 21. The roots of these three legs are the yoke portion 24. Connected by. As shown in FIG. 2, an inclined surface portion 25 that is obliquely inclined is formed from the middle of the end side wall 26 of the yoke portion 24 toward the lower surface in contact with the terminal plates 9 and 10. FIG. 3 is a perspective view showing a transformer constructed by using the E-shaped core constructed as described above. In FIG. 3, the same parts as those in the conventional transformer are designated by the same reference numerals.

As is apparent from FIG. 2, the creepage distance (SL) from the pins 11 and 12 of the high voltage transformer to the core 20 (SL
1 + SL2) is the same as that of the conventional high voltage transformer shown in FIG. 10, but since the slope portion 25 is formed in the yoke portion 24, the area A on the right side of the dotted line SL is increased by more than the conventional core. To do. In other words, the area of the main body of the yoke portion 24 is reduced by A without reducing the creepage distance, and the yoke portion 24 can be formed in a small size. Also, the inclined portion 2
5 is provided, the length of the yoke portion 24 in the direction of arrow B in FIG. 2 can be made longer than that of the conventional one. For this reason, the portion having the area A becomes a kind of reinforcing portion, and even if stress is applied in the direction of the tuning fork movement in which the tips of the side legs 22 and 23 come close to or away from each other, the slope portion 25 causes breakage. There is nothing to wake up.

4 and 5 are partial sectional views of a yoke portion showing another embodiment. In the embodiment shown in FIG. 4, the slope 3
Reference numeral 5 constitutes an arcuate slope portion which is recessed inward. Further, in the embodiment shown in FIG. 5, the slope portion 45 is a linear slope portion, but the slope portion 46 is also provided on the upper surface side to have a trapezoidal sectional shape.

The high voltage transformer shown in FIG.
Since 12 is located above the lower surface of the terminal boards 9 and 10, when mounting this on the printed wiring board, a square hole for fitting the terminal board into the printed wiring board is formed, and the pins 11 and 12 must be level with the wiring copper foil on the printed wiring board. Therefore, in the present invention, as shown in FIG. 6, it is preferable that the pins 15 and 16 are bent in a stepped shape and the portion of the printed wiring board connected to the wiring copper foil is held flush with the bottom surface of the terminal board.

Further, when the number of pins provided on the terminal plate is small and these are provided at the central portion of the terminal plate, the inclined portion 61 is provided only at the central portion as shown in FIG. Reinforcing parts 62 and 63 are left on the end faces. By leaving the reinforcing portions 62 and 63 in this way, when stress is applied to the side leg, the probability of breakage is lower than in the above-described embodiment.

[0014]

As described in detail above, the present invention is
Since the inclined part that is one surface of the yoke part and inclines from the part that contacts the terminal plate toward the end side wall of the yoke part is provided, it is not necessary to make the core and the terminal plate larger than the conventional one, and the same creepage A distance can be secured between the core and the pin.

Further, since the length of the yoke portion in the width direction can be made longer than that of the conventional one, even if the tip ends of the side legs come close to or away from each other, even if stress is applied in the direction of the tuning fork movement, the slope portion causes However, it does not cause any breakage.

[Brief description of drawings]

FIG. 1 is a perspective view of a core according to the present invention.

FIG. 2 is a partial sectional view of the core.

FIG. 3 is a perspective view of a high voltage transformer using a core according to the present invention.

FIG. 4 is a perspective view showing another embodiment of the present invention.

FIG. 5 is a perspective view showing another embodiment of the present invention.

FIG. 6 is a partial cross-sectional view showing an improved specific example of the terminal board.

FIG. 7 is a perspective view showing another embodiment of the present invention.

FIG. 8 is a perspective view showing a conventional core.

FIG. 9 is a perspective view showing a bobbin for a high voltage transformer.

FIG. 10 is a perspective view showing a conventional high voltage transformer.

[Explanation of symbols]

 20 ... E-shaped core 21 ... Central leg 22 ... Side leg 23 ... Side leg 24 ... Yoke part 25 ... Inclined part 26 ... End side wall

Claims (2)

[Claims] 1. A central leg around which a coil is wound, a yoke portion connected to the central leg in a T-shape, and arranged at both ends of the yoke portion and arranged in parallel with the central leg from the end portion. A core for a high-voltage transformer having two side legs, further comprising a yoke member provided with an inclined portion inclined from one surface of the yoke portion, which is in contact with the terminal plate, to an end side wall of the yoke portion. A core for high voltage transformers. 2. The core for a high voltage transformer according to claim 1, wherein a cross-sectional shape of the inclined portion is an arc shape.