JPH0722059B2 - Flyback transformer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a flyback transformer used in a television receiver or the like.

2. Description of the Related Art Conventionally, flyback transformers have been used as sources of high voltages and various voltages required for television receivers, and inexpensive and highly reliable ones are desired.

An example of a conventional flyback transformer will be described below with reference to the drawings.

FIGS. 4a and 4b show the structure of a conventional flyback transformer. In FIG. 4, 1 is a gap paper, 2 is a core, 3 is a winding lead terminal, 4 is a high voltage winding bobbin, and 5 is 1.
The secondary winding bobbin, 6 is a secondary winding bobbin, 7 is a high voltage winding, 8 is a primary winding, and 9 and 10 are secondary windings. FIG. 3 shows a circuit diagram of these windings. In FIG. 3, 12 is a flyback transformer. However, the high voltage winding is not shown. Further, 11 is an auxiliary winding relating to the present invention.

In FIG. 3, a DC voltage is applied to the primary winding 8 from the terminal 13 via the overcurrent protection device 14. The pulse generated by the secondary windings 9 and 10 driven by the switching circuit 15 is rectified by a rectifying circuit composed of the diode 16, the capacitor 17, the diode 18 and the capacitor 19, and supplied to the loads 20 and 21, respectively. However, 20 is a heavy load and 21 is a light load.

Problems to be Solved by the Invention However, in the above configuration, the overcurrent protection device 14
There is a problem with the operation settings of. When the heavy load 20 is short-circuited, the change in the load is large and the change in the primary winding 8 is large as compared with the normal operation. Therefore, it is easy to set the operation of the overcurrent protection device 14 in the normal operation range without malfunction. However, when the light load 21 is short-circuited, the change in the load is small and the change in the primary winding 8 is small compared to the normal operation. Therefore, if the overcurrent protection device 14 is set to operate in such an abnormal condition, there is a problem that it malfunctions in the normal operating range.

Further, although other means such as inserting a protection resistor in series with the diode 18 have been conventionally performed, they are incomplete. The reason is that the primary winding 8 and the secondary winding 10 are loosely coupled, and even if the load is short-circuited, the change in the load is smaller than in the normal state.

As described above, conventionally, it is difficult to protect against an abnormality such as a short circuit of the light load 21, and when the abnormality occurs, the secondary winding 10 generates heat, which further accelerates heat generation with a rare short of one turn.
There was a problem that the filler was heated and smoked.

SUMMARY OF THE INVENTION In view of the above problems, the present invention provides a flyback transformer that prevents smoke generation when an abnormality occurs and can be easily implemented at low cost.

Means for Solving the Problems In order to solve the above problems, the flyback transformer of the present invention uses a plurality of secondary windings using wires insulated by a coating melted by heat and a bare wire or heat. An auxiliary winding using a wire insulated by a coating is provided, and one end of this auxiliary winding is electrically connected to one end of any secondary winding, and the other end of this auxiliary winding The secondary winding to be mechanically connected to the secondary winding is mechanically contacted.

Action The present invention has the above-described configuration so that when the load connected to the secondary winding is short-circuited (at the time of abnormality), the coating of the winding melts due to heat generation of this winding and makes mechanical contact. By being electrically connected to the auxiliary winding, the heavy load winding is short-circuited via the auxiliary winding.

As described above, by converting a small change in the light load into a large change in the normal operation, the overcurrent protection device 14 is operated, and the smoking of the filler is immediately prevented.

Embodiment A flyback transformer according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural diagram of a flyback transformer according to an embodiment of the present invention. FIG. 2 is an enlarged view of FIG. In FIG. 1, reference numeral 11 denotes an auxiliary winding, and the other components having the same numbers as those shown in FIG. The secondary winding 9 is composed of a wire which is insulated by a coating which is melted by heat, and the auxiliary winding 11 is composed of a bare wire or a wire which is insulated by a coating which is melted by heat.

First, the auxiliary winding 11 shown in FIG. 2 is configured to contact the secondary winding 10 for light load orthogonally and mechanically every turn. Further, one end of the auxiliary winding 11 is connected to a terminal of the secondary winding 9 for heavy load on the side opposite to the reference potential, as shown in FIG.

In FIG. 3, when an abnormality occurs in the load 21 and the load is short-circuited, the light-load secondary winding 10 generates heat, and this heat causes the coating to melt somewhere in the winding, causing a short-circuit. If it is between a and b in FIG. 2, there is a possibility that the winding in the meantime will further generate heat and heat the packing material filled in the surroundings to cause smoke or sometimes an explosion. However,
Due to the heat generation of this winding, the auxiliary winding 11 is also electrically connected and the heavy load secondary winding 9 becomes a closed circuit. As a result, a large current flows through the primary winding 8 to operate the overcurrent protection device 14,
It is possible to prevent the smoke and explosion as described above.

As described above, according to this embodiment, one end of the auxiliary winding 11 is connected to the terminal on the opposite side of the reference potential of the heavy load secondary winding,
Moreover, by making the auxiliary winding 11 mechanically contact the secondary winding 10 for light load, it is possible to prevent smoke or explosion of the flyback transformer that occurs when the load is short-circuited with light load.

Further, in order to secure the effect of the present invention, a material having a melting temperature of the auxiliary winding or the coating of the secondary winding mechanically contacting with the auxiliary winding is as low as possible within a range that does not hinder normal operation. Is preferred.

As described above, according to the present invention, one end of the auxiliary winding is electrically connected to one end of an arbitrary secondary winding, and the auxiliary winding is electrically connected to the secondary end. By making mechanical contact with a secondary winding that is different from the winding, smoke and explosion of the flyback transformer due to heat generation of the secondary winding can be prevented, and it is cheap and easy to implement. It can be done.

[Brief description of drawings]

FIG. 1 is a sectional view showing the structure of a flyback transformer according to an embodiment of the present invention, FIG. 2 is an enlarged view thereof, FIG. 3 is a circuit diagram of the flyback transformer and its periphery, and FIG. 4 is a conventional example. It is sectional drawing which shows the structure of a flyback transformer. 1 ... Gap paper, 2 ... Core, 3 ... Winding terminal,
4 ... High voltage winding bobbin, 5 ... Primary winding bobbin, 6
…… Secondary winding bobbin, 7 …… High voltage winding, 8 …… Primary winding, 9,10 …… Secondary winding, 11 …… Auxiliary winding.

Claims (1)

[Claims] 1. A plurality of secondary windings made of a wire insulated by a heat-melting coating, and an auxiliary winding made of a bare wire or a wire insulated by a heat-melting coating. The end is electrically connected to one end of the secondary winding, and the auxiliary winding is mechanically contacted with a secondary winding different from the electrically connected secondary winding. Flyback transformer.