JPS6214652Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transformer that is advantageously used in a public listening branch of a television receiver.

The transformers used in such branching switches are small and have a small number of turns, and electrical characteristics vary from product to product depending on variations in the spacing between the primary and secondary coils. Furthermore, if these coils are unnecessarily long, there is a problem in that the insertion loss of the splitter becomes large when the frequency to be transmitted becomes high.

An object of the present invention is to provide a transformer with improved quality and uniform electrical characteristics.

The present invention includes a cylindrical longitudinal core 13, 26 having insertion holes 43, 27, 28, and a wiring board 14, 29, which is tightly fitted into the insertion hole 43, 27, 28.
and first leg portions 15, 30, 31 whose free ends protrude from the cores 13, 26 in the longitudinal direction;
Legs 15, 30, 31 and cutouts 17, 44, 45
second leg portions 16, 32, 33 extending through the cores 13, 26, and formed on the surfaces of the first leg portions 15, 30, 31;
and protrudes from both ends of the cores 13 and 26 in the longitudinal direction,
Wiring substrates 14, 29 having one longitudinal coil 18, 34, 35 extending near the notches 17, 44, 45;
26, and the one coil 18, 34,
The other coil 21, 36, 3 magnetically coupled to 35
7, and pins 19, 20, 3 that are electrically connected to the portions of the one coil 18, 34, 35 that protrude from both ends of the cores 13, 26 in the longitudinal direction.
8 and 39.

FIG. 1 is an electrical circuit diagram of an embodiment of the present invention. A high frequency signal is inputted from an input terminal 2 of this splitter 1 from a signal source 3 such as an antenna. A part of the high frequency signal from the input terminal 2 is applied from the primary winding 5 of the transformer 4 to the output terminal 6 of the main line to a load 7 such as a receiver. The remainder of the high frequency signal from the input terminal 2 is applied to the receiver 9 via the resistor R1 and the output terminal 8 for branching. A secondary winding 10 of the transformer 4 is connected to the output terminal 8 . The high frequency signal from the input terminal 2 is sent to the primary winding 5.
When the current flows in the direction of arrow 11, a voltage is induced in the secondary winding 4 in the direction of arrow 12. The current induced in the secondary winding 10 and the current flowing through the resistor R1 are applied to the receiver 9 from the output terminal 8 for branching.

When a signal such as noise enters the splitter 1 from the receiver 9 connected to the output terminal 8 for branching, the signal such as noise flows from the resistor R1 through the primary coil 5 in the direction of the arrow 11. Further, signals such as noise flow into the secondary coil 10 in the opposite direction to the arrow 12. The current flowing through the secondary coil 10 induces a voltage in the primary coil 5 in the opposite direction to the arrow 11. In this way, signals such as noise are canceled out in the primary coil 5. Therefore, signals such as noise from the branching output terminal 8 are not led out from the output terminal 6, and there is no mutual interference between the receiver 9 and the load 7.

FIG. 2 is a perspective view of the transformer 4, and FIG. 3 is a sectional view of the transformer 4 at right angles to the axis. One leg 15 of a roughly U-shaped printed wiring board 14 is tightly fitted into the insertion hole 43 of the right cylindrical core 13 . This leg 15 passes through the axis of the core 13. Another leg 16 is external to the core 13. A notch 17 between the legs 15 and 16 holds the core 13. A linear primary coil 18 is printed and wired on one surface of the printed wiring board 14 . This primary coil 18
extends over the entire length of core 13, and
It protrudes slightly outward from both ends of 3. Pins 19 and 20 as lead wires electrically connected to both ends of the primary coil 18 are provided on the printed wiring board 14 so as to face downward in FIG.
In the core 13, along the printed wiring board 14,
multiple times (for example, 3 to 4 times) adjacent to the secondary coil 18.
A secondary coil 21 having a number of turns of approximately The strands of the secondary coil 21 are covered with an electrically insulating outer covering. Core 13 of primary coil 18
The side portion 18a close to the inner circumferential surface of the coil has a slight gap from the end of the notch 17, thereby ensuring that the primary coil 18 and the core 13 are electrically isolated. It is maintained.

FIG. 4 is a graph showing the experimental results of the inventor of the present invention. In the embodiment shown in FIGS. 1 and 2,
The insertion loss of the main line output terminal 6 when the frequency of the high frequency signal applied to the input terminal 2 of the branching device 1 is changed is shown by a line 11. here,
The resistance R1 is 240Ω, and the resistance R2 provided for impedance matching at the output terminal 8 for branching is 124Ω. According to the embodiment of the present invention, the insertion loss is relatively small even when the frequency increases as shown by line l1. For reference, the above-mentioned prior art is constructed by inserting a wire serving as a primary coil into a core and manually winding a secondary coil close to the primary coil.
As shown in line 12, the insertion loss significantly increased as the frequency increased. The reason for this is presumed to be that in the prior art, the wires of the primary coil tend to be undesirably long, which increases the inductance. The pins 19 and 20 are connected to the printed wiring 40 of the printed wiring board 22 of the turnout 1.
41 and is fixed.

FIG. 5 is a perspective view of another embodiment of the present invention, and FIG. 6 is a cross-sectional view thereof. This embodiment is also a transformer 25 that can be used in the branch 1 or the like. What should be noted in this embodiment is that the core 26 has two right cylindrical insertion holes 27 and 28 formed therein. The legs 30 and 31 of the printed wiring board 29 are tightly fitted into the insertion holes 27 and 28.
Legs 32 and 33 on both sides of printed wiring board 29
is outside the core 26. Notches 44 and 45 are formed between the legs 30 and 31 and the legs 32 and 33. The legs 30 and 31 lie within one plane that includes the axes of the insertion holes 27 and 28. Linear primary coils 34, 35 are printed on the legs 30, 31 at positions farthest from each other. Secondary coils 36, 37 are magnetically coupled to these primary coils 34, 35 and are wound along their legs 30-33. Primary coil 35
Pins 38 and 39 as lead wires are connected to these pins 38 and 39, and these pins 38 and 39 are fixed and electrically connected to the printed wiring of the printed wiring board 40 of the turnout. Another primary coil 34
The same applies to According to such a configuration, one core 26 includes (a) a transformer including a primary coil 34 and a secondary coil 36, and (b) another transformer including a primary coil 35 and a secondary coil 37. A transformer is formed, which has the advantage of requiring a small installation space.

The present invention can be widely implemented not only in transformers used in branching switches, but also in relation to other transformers.

As described above, according to the present invention, the wiring board 14,
The first leg portions 15, 30, 31 formed in 29
are the insertion holes 43, 27, 28 of the longitudinal cores 13, 26.
This first leg 15, 30, 3 is tightly fitted into the
One of the coils 18 , 34 , 35 is formed on the surface of the core 1 near the notches 17 , 44 , 45 , and the cores 13 , 26 have the notches 17 , 44 , 45 formed thereon.
Since the other coils 21, 36, 37 are wound near the coil 45, the one coil 18, 3
4, 35 and the other coil 21, 36, 37
There is no deviation in the gap between the two and it is possible to eliminate variations in electrical characteristics.

The one coil 18, 34, 35 is formed on the surface of the first leg portion 15, 30, 31, and is located at both longitudinal ends of the core 13, 26 (FIGS. 2 and 5).
It protrudes and extends to both ends in the left and right direction in the figure. Pins 19 and 20 are electrically connected to and erected at the portions of the one-side coils 18, 34, and 35 that protrude from the cores 13 and 26, respectively. Therefore, this pin 19,2
0, 38, and 39 can be connected to the wiring boards 22, 40, etc., and can also be attached to support the cores 13, 26. Therefore, the configuration is simplified.

The first legs 15, 30, 31 are tightly fitted into the insertion holes 43, 27, 28 of the cores 13, 26, and the cores 13, 26 are fixed to the wiring boards 14, 29. 26, the other coil 2
1, 36, 37 can be carried out while supporting the wiring boards 14, 29,
Good workability.

[Brief explanation of the drawing]

Fig. 1 is an electrical circuit diagram of one embodiment of the present invention;
The figure is a perspective view of the transformer 4 used in the turnout 1 shown in the first figure, FIG. 3 is a cross-sectional view at right angles to the axis of the transformer 4, FIG. FIG. 6 is a perspective view of a transformer 25 according to another embodiment of the invention, and FIG. 6 is a sectional view taken at right angles to the axis of the transformer 25 shown in FIG. 4, 25...Trance, 24, 27, 28...
Insertion hole, 13, 26...core, 14, 22, 2
9,40...Printed wiring board, 18,34,3
5,...Primary coil, 21,36,37...Secondary coil.

Claims (1)

[Claims for Utility Model Registration] Cylindrical longitudinal cores 13, 26 having insertion holes 43, 27, 28; wiring boards 14, 29, which are tightly fitted into the insertion holes 43, 27, 28;
and first leg portions 15, 30, 31 whose free ends protrude from the cores 13, 26 in the longitudinal direction;
Legs 15, 30, 31 and cutouts 17, 44, 45
second leg portions 16, 32, 33 extending through the cores 13, 26, and formed on the surfaces of the first leg portions 15, 30, 31;
and protrudes from both ends of the cores 13 and 26 in the longitudinal direction,
Wiring boards 14 and 29 each have one longitudinal coil 18, 34, 35 extending near the notches 17, 44, 45;
26, and the one coil 18, 34,
The other coil 21, 36, 3 magnetically coupled to 35
7, and pins 19, 20, 3 that are electrically connected to the portions of the one coil 18, 34, 35 that protrude from both ends of the cores 13, 26 in the longitudinal direction.
A transformer comprising: 8, 39.