JPH0536259Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a coaxial rotary transformer used for transmitting signals between a rotating side and a stationary side in a VTR etc. This invention relates to a coaxial rotary transformer that is equipped with a ring-shaped terminal that is attached to one end of the transformer and a flexible wiring board that is attached to the ring-shaped terminal, and that improves the workability of connecting coil terminals and the reliability of the connecting part.

[Prior Art] A coaxial rotary transformer that transmits and receives signals between a rotating system and a stationary system by electromagnetic coupling is conventionally known.
In this type of rotary transformer, two cylindrical cores are coaxially provided with a slight gap between them, and coils are attached to their opposing surfaces, respectively, so that the cores rotate relative to each other. Various designs have been devised regarding structures for drawing out the terminals of each coil to the outside.

As a typical conventional technique, a plurality of terminal pins are planted on the end face of a ring-shaped terminal, the ring-shaped terminal is attached and fixed to one end of a cylindrical core, and the terminal of each coil is tied around the terminal pin. There is a structure that connects by soldering (for example,
-189909).

[Problems to be solved by the invention] However, with this conventional technology, it is necessary to attach a large number of terminal pins to the ring-shaped terminal, and it is necessary to wrap the coil terminal around each terminal pin, which makes it difficult to use multiple channels. Indeed, there is a drawback that the number of terminal pins increases, which significantly impairs work efficiency.

Furthermore, there is a risk that wire breakage may occur due to mechanical stress due to variations in the work of binding the coil ends to the terminal pins.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, and to provide a coaxial rotary transformer that has good workability in connecting coil terminals, has a simplified structure, and does not cause disconnection. .

[Means for Solving the Problems] The present invention, which can achieve the above objects, includes a cylindrical core to which a coil is attached, a ring-shaped terminal attached to one end of the cylindrical core, and a ring-shaped terminal attached to the ring-shaped terminal. This is a coaxial rotary transformer equipped with a flexible wiring board that is attached.

The ring-shaped terminal has a structure in which a step is provided on the outer peripheral side and a protrusion for positioning is formed on the step surface. On the other hand, the flexible wiring board has a positioning engagement part such as a hole or notch that engages with the protrusion. The flexible wiring board is aligned and adhered to the step surface by the engaging portion and the protrusion, and the coil terminal is connected to a connection land provided on the board.

[Function] The flexible wiring board is positioned and connected to a stepped surface located closer to the cylindrical core than the end surface of the ring-shaped terminal, and the coil terminal is soldered onto the connecting land. Therefore, the coil winding is electrically connected to the external circuit by the flexible wiring board.

The flexible wiring board is located closer to the core than the end surface of the ring-shaped terminal, and the connection part should be protected by working so that the height of the coil terminal soldered to the connection land is not higher than the end surface. In addition, even if the entire end face is bonded, no short circuit will occur.

[Embodiment] FIG. 1 is a longitudinal sectional view showing an embodiment of a coaxial rotary transformer according to the present invention, and FIG. 2 is a plan view thereof.

This rotary transformer includes a cylindrical core 10, a ring-shaped terminal 12 attached to one end of the cylindrical core, and a flexible wiring board 14 attached to the ring-shaped terminal 12. This embodiment is an example applied to an outer cylindrical core 10 of a rotary transformer, and although not shown, an inner cylindrical core is located coaxially inside the cylindrical core 10. is constructed so that it remains stationary and the inner cylindrical core rotates. Although not shown, a plurality of winding grooves are formed on the inner peripheral surface of the cylindrical core 10, and coils are mounted in the grooves.

The ring-shaped terminal 12 has a step on the inner circumferential side, and has a structure in which one end of the cylindrical core 10 is inserted and fixed to the step, and a step is also provided on the outside. This step is set to be slightly larger than the thickness of the flexible wiring board 14 and the height required for soldering for connection. Further, a positioning protrusion 16 is integrally formed on the stepped surface 12a. Here, as shown in FIG. 2, two locations are provided approximately 90 degrees apart.

The flexible wiring board 14 has a structure including an annular portion 14a that fits exactly into the stepped surface and lead portions 14b protruding from both sides of the annular portion 14a, and has positioning holes corresponding to the formation positions of the positioning protrusions 16. 18 are provided. Also, the annular part 1
A connecting land 22 for connecting the coil terminal 20 is provided at an appropriate location on the lead portion 14a, and a lead pattern 26 is formed by printed wiring technology to continue with the connecting land 22 and reach the connector electrode 24 at the end of the lead portion 14a. be.

The flexible wiring board 14 is fixed to the step surface 12a of the ring-shaped terminal 12 by fitting the positioning hole 18 into the positioning protrusion 16 with an adhesive. The coil terminal is drawn out toward the ring-shaped terminal 12 using a terminal drawing groove (not shown) formed in the core 10.
It is pulled out using the groove 28 formed therein and soldered to a predetermined connection land 22. When soldering, be careful that the height of the soldered connection land is not higher than the end surface of the terminal. The end face of the terminal is glued and fixed to the cylinder, but as mentioned above, the top face of the solder is lower than the end face of the terminal, creating a gap.
There is no risk of short circuit even if no special insulation treatment is performed.

FIG. 3 is a plan view showing another embodiment of the present invention. As shown in the figure, the flexible wiring board 14 may have a rectangular shape so that the lead portion 14b can be drawn out in only one direction. Further, the positioning engagement portion may be a notch 38. The rest of the structure may be the same as that shown in FIG. 2, so corresponding parts will be designated by the same reference numerals and their description will be omitted.

[Effects of the invention] As the invention is a coaxial rotary transformer having a structure in which a flexible wiring board is positioned and attached to a ring-shaped terminal as described above, the work of attaching a large number of terminal pins to a ring-shaped terminal is not necessary. In addition, there is no need to tie the coil terminals together, and it is only necessary to directly solder the drawn-out coil terminals to the connection lands of the flexible wiring board, which has the effect of significantly improving assembly work efficiency.

In addition, since the flexible wiring board can be fixed firmly enough so that it does not rotate using the positioning member and adhesive, it is possible to prevent the wires from breaking due to movement, and to make sure that all the wires are stored in the groove or that there is no step. Because it fits into the area, it is protected and has the effect of improving reliability.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing essential parts of a coaxial rotary transformer according to the present invention, FIG. 2 is a plan view thereof, and FIG. 3 is a plan view showing another embodiment of the present invention. 10... Cylindrical core, 12... Ring-shaped terminal, 14... Flexible wiring board, 16...
Positioning protrusion, 18...Positioning hole, 20...
...Coil terminal, 22...Connection land.

Claims (1)

[Scope of utility model registration request] It comprises a cylindrical core to which a coil is attached, a ring-shaped terminal attached to one end of the core, and a flexible wiring board attached to the ring-shaped terminal, and the ring-shaped terminal has a step on the outer circumference side. A coaxial rotating type in which a positioning protrusion is provided on a stepped surface, a flexible wiring board having a positioning engagement portion is aligned and adhered to the stepped surface, and the coil terminal is connected to a connection land formed on the board. Trance.