JPH0347310Y2 - - Google Patents

Description

[Detailed Description of the Invention] (a) Industrial Application Field The present invention relates to a flyback transformer, and particularly to a small flyback transformer used for an electronic viewfinder of a video camera.

(b) Prior Art In a conventional small flyback transformer 1 shown in FIG. 4, 2 denotes a low voltage coil 3 and a high voltage coil 4.
14 is a terminal board in which a plurality of external connection terminal pins 4, 4... are implanted, and 5, 6 are base portions 5a, 6a, respectively, and a coil bobbin extending perpendicularly to the base portions 5a, 6a. 1. First and second U-shaped ferrite cores consisting of second leg portions 5b, 5c, 6b, and 6c, 7 the resin, 8 an insulating case with one end open, and 10 and 11 adhesive.

Next, to explain the manufacturing process of such a flyback transformer, especially the process before and after installing the ferrite cores 5 and 6, first, after combining the terminal board 14 onto the coil bobbin 2 around which the low-voltage coil 3 and high-voltage coil 4 are wound, After completing the wiring, the first leg portion 5b of the first core 5 is inserted into the hollow portion of the coil bobbin 2, and the base portion 5a is fitted into a fitting portion (not shown) of the terminal board 14. At this time, an adhesive 10 is applied between the base 5a and the terminal board 3, whereby the first
Core 5 is adhesively fixed. After that, after applying a two-component adhesive [for example, Cemedine Y-352AB (Cemedine Co., Ltd.)] 11 to the end surfaces of the first and second leg portions 6b and 6c of the second core 6, [the first and second cores 5,6
The adhesive applied to the first legs 5b, 6c of the first core 5 is not shown], the first and second legs 5 of the first core 5.
After the adhesive 11 has hardened, it is placed in an insulating case 8, filled with an insulating resin 7 such as urethane resin or silicone rubber, and hardened to complete the process.

However, in the above manufacturing process, the first
It takes several minutes for the two-component adhesive applied to the abutting portions of the second cores 5 and 6 to harden, so during this time there is a A crimping jig, etc. is used.

On the other hand, in small flyback transformers used in electronic viewfinders of video cameras, etc., there is a particular need to reduce power consumption, so the length of the core gap formed at the butt part of the first and second cores is has become extremely small, about 50 μm. In the case of such a small core gap, variations in the tightening force when fixing the core will directly manifest as large variations in the inductance value of the primary coil, which may cause variations in the high-voltage output voltage value of the flyback transformer. There is. In order to prevent this, methods such as improving the precision of the core fixing jig or measuring the inductance value of the primary coil when combining the ferrite cores are being taken. This has the disadvantage of causing a decrease in productivity.

Another possible countermeasure is to use instant adhesive at the butt part of the core, but in that case, there is a risk that the insulating resin and instant adhesive will react and cause undesirable effects. , undesirable.

For example, Cemedine 3000 is used as the instant adhesive mentioned above.
When [trade name: Cemedine Co., Ltd.] was used, it was confirmed that the urethane resin and silicone rubber applied near the adhesive remained uncured.

In addition, in FIGS. 4 and 5, 9 is a pair of ribs provided to prevent the second core 6 from rotating, and such ribs are provided to only prevent the rotation of the core. A flyback transformer is described, for example, in Japanese Utility Model Application No. 142816/1983.

(c) Problems to be solved by the invention This invention attempts to improve the productivity and reduce the cost of flyback transformers.

(d) Means for solving the problem A holding piece was provided to press and hold the base of the second core against the coil bobbin.

(E) Function The second core is fixed to the coil bobbin by the holding piece.

(f) Embodiment An embodiment of the present invention will be explained with reference to FIGS. 1 to 3, and the same parts as in FIGS. 4 and 5 will be given the same reference numerals and their explanation will be omitted. .

That is, the flyback transformer 1' of the present invention
Now, terminal board 14 of coil bobbin 2
Elastic claw pieces 13, 13 are respectively provided on the pair of ribs 9, 9 provided on the side flange 12 on the side that is not combined with the ribs 12, and the base 6a of the second core 6 is held against the elastic force of the claw pieces 13, 13. It is inserted between the ribs 9 by pushing it in from the direction of arrow A (see FIG. 3). With this configuration, the base portion 6a of the second core 6 is pressed against the end face flange 12 of the coil bobbin 2 while being held between the ribs 9, 9 by the predetermined elastic force of the claw pieces 13, 13. 1st and 2nd leg portions 5 of 1 core 5
It is held with such pressure that it maintains a predetermined distance from the end faces of b and 5c. In addition, a synthetic resin gear spacer (not shown) is usually installed at the butt part of the first and second cores.
will be placed.

(G) Effects of the invention According to the invention, since the second core is held under pressure against the coil bobbin by the claw pieces, a jig for fixing the core is not required, and the productivity of the flyback transformer is improved. do. This also has the effect of reducing costs.

[Brief explanation of drawings]

Fig. 1 is a side sectional view of the flyback transformer of the present invention, Fig. 2 is a plan sectional view thereof, and Fig. 3 is its B-
It is a sectional view taken along the line B'. FIG. 4 is a side sectional view of a conventional flyback transformer, and FIG. 5 is a plan sectional view thereof. 2...Coil bobbin, 3...Low voltage coil, 4...
...High voltage coil, 5...First core, 6...Second core, 5a, 6a...Base, 5b, 6b...First leg, 5c, 6c...Second leg, 9...Rib, 13
...Claw piece, 14...Terminal board.

Claims (1)

[Claim for Utility Model Registration] A terminal board in which a plurality of terminal pins are implanted is provided on one end side of a coil bobbin around which a high-voltage coil and a low-voltage coil are wound.
The base of the first core among the cores is adhesively fixed to the terminal board, and the base of the first core is fixed to the terminal board.
The legs are joined to the first and second legs of the second core inside the coil bobbin, and the second leg is joined to the first and second legs of the second core outside the coil bobbin, respectively, and the high voltage coil, the low voltage coil, the coil bobbin and the first, In a flyback transformer in which a combination of second cores is housed in an insulating case and filled with an insulating resin and hardened, the second core 6 is provided with an end face flange 12 at the other end of the coil bobbin 2 to control the rotation of the second core 6. A pair of ribs 9, 9 sandwiching the end of the base 6a of the second core 6 to prevent the above-mentioned A pair of elastic claw pieces 13, 1 that hold the base 6a of the second core 6
A flyback transformer comprising 3 and.