JPH0749777Y2 - Inverter transformer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a high-frequency inverter transformer used in a fluorescent tube lighting device, a magnetron driving device, or the like.

2. Description of the Related Art This type of inverter transformer is operated at a high frequency of 25 kHz, for example, and a load such as a fluorescent tube or a magnetron is connected to the secondary side. Since the fluorescent tube and the magnetron are non-linear loads, an excessive current flows when a voltage is applied. In order to limit this current, a method of lowering the secondary output voltage of the inverter transformer when the current flows is adopted.
Therefore, in the inverter transformer, the magnetic coupling between the primary coil and the secondary coil is deteriorated.

Conventionally, such an inverter transformer has a structure as shown in FIG. That is, the U core 11 is combined and the gap spacers 14 and 14 'are inserted into the abutting surfaces to form a magnetic gap, and the primary coil 16 and the secondary coil 18 are provided on one magnetic leg. 15 and 17 are coil bobbins.
The primary coil 16 and the secondary coil 18 are separated by a predetermined distance in order to deteriorate the magnetic coupling.

Problems to be Solved by the Invention In such a conventional configuration, there is a problem in that the magnetic flux of the gap spacer 14 'causes a leakage magnetic flux, which causes the coil to generate heat. The larger the gap of the magnetic gap, the more the leakage magnetic flux and the larger the heat generation. If the heat generation is large, the insulating material of the transformer is required to have high heat resistance, which increases the cost of the transformer.

The present invention solves such a problem and provides an inexpensive and highly reliable inverter transformer which reduces heat generation of a coil.

Means for Solving the Problems In order to solve this problem, the present invention shortens one magnetic leg of the U core to increase one magnetic gap and decrease the other magnetic gap. The magnetic leg on the side of the smaller gap is provided with the primary coil and the secondary coil.

Action With this configuration, the magnetic gap on the side where the coil is provided is made small and the other magnetic gap is made large, whereby a magnetic resistance equivalent to that of the conventional gap can be obtained. Further, since the magnetic gap on the coil side is small, the leakage magnetic flux is small, and therefore the heat generation of the coil is reduced.

Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a front view of an inverter transformer according to an embodiment of the present invention. 1, 1'is a U core and 2, 3 are gap spacers. The magnetic leg 4 of the U cores 1,1 'is shorter than the other magnetic leg 4', and therefore, when the U cores 1,1 'are butted, the magnetic gap becomes large like the gap spacer 3. Reference numerals 5 and 7 are coil bobbins, 6 is a primary coil, and 8 is a secondary coil.

As described above, according to the present invention, since the magnetic gap on the side where the coil is located is small, the heat generation of the coil is small, and the heat resistance of the insulating material used is low, so the material cost is low, An inexpensive transformer can be provided as a whole.

[Brief description of drawings]

FIG. 1 is a front view of an inverter transformer according to an embodiment of the present invention, and FIG. 2 is a front view of a conventional inverter transformer. 1,1 ′ …… U core, 2,3 …… Gap spacer, 4,4 ′…
… Magnetic legs, 5, 7 …… Coil bobbin, 6 …… Primary coil, 8
...... Secondary coil.

Claims (1)

[Scope of utility model registration request] 1. A gap is provided between two U-shaped cores, and at least one of the two U-shaped cores is shortened on one side to shorten the gap between the core butting surfaces. An inverter transformer in which the primary coil and secondary coil are installed side by side in a magnetic leg with a small gap, with only one side enlarged.