JPH0284703A - Rotary transformer - Google Patents

Abstract

PURPOSE:To obtain a rotary transformer having good characteristics which can reduce leakage inductance by providing a nonmagnetic material between a conductor piece which is drawn out from a coil conductor on magnetic core to the rear side of the core and the magnetic core. CONSTITUTION:This rotary transformer in which coil conductors facing the facing surfaces side of the first and second magnetic cores are formed is constituted in such a way that two conductor pieces 66 and 68 are provided in through holes communicating with the facing surface side and the opposite surface side of the above-mentioned magnetic core 50 formed at each coil conductor section of the magnetic core 50 by molding with a nonmagnetic material 70 and both ends 62 and 64 of the above- mentioned coil conductors are respectively connected with the end sections of the conductor pieces 66 and 68 on the facing surface side so that signal from each coil conductor can be led to the opposite surface side of the magnetic core 50 through the conductor pieces 66 and 68. For example, both ends 62 and 64 of a spiral thin-film coil 52 (or 54) are respectively connected with conductor lines 66 and 68 enclosed with glass and the conductor lines 66 and 68 are not brought into contact with the magnetic core, but indirectly brought into contact with the magnetic core 50 through a glass layer 70.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary transformer used, for example, when transmitting and receiving signals to and from a video head.

C. Prior Art] A rotary transformer has a structure in which one coil is formed on a magnetic core on the stator side, and the other coil is formed on a magnetic core on the rotor side. By connecting the coil on the rotor side to the video head, the coil is connected to the rotating video head. Signals can be sent and received without contact.

``For example, as a conventional rotary transformer,
Publication No. 1-201405, JP 62-48007
There is one that was disclosed in the Publication No. 1, and another that was commercialized by Mitsumi Electric Co., Ltd. as the "Excel Rotary Transformer."

Among these, the one disclosed in Japanese Unexamined Patent Publication No. 61-201405 will be representatively explained with reference to FIG. In the same figure, (A) is a perspective view showing the outline of the magnetic core, and (B) is a partial perspective view enlarging the part surrounded by the - dotted chain line in (^), and the ff-ff line in this figure A cross-section along the arrow is shown in (C).

In these figures, the magnetic core 10 is formed into a disk shape from a material such as ferrite. Coils 12 and 14 are provided concentrically on the side of the magnetic core lO that faces the other magnetic cores. And these coils 12.
14, a short ring 16 is similarly provided concentrically.

Among the coils 12 and 14, the thin film conductor 18 is formed in a spiral shape (see (B) in the same figure). The thin film conductor 1B is formed by known means such as vapor deposition and sputtering. Through holes 22 are provided in the magnetic core lO where both ends 20 of this S* conductor 18 are located, and the thin film conductor 18 is inserted through the magnetic core lO.
A connecting conductor 24 is drawn out to the back side of the O.

Note that an appropriate overcoat 26 is applied on the thin film conductor 18 to improve durability, and the thin film conductor 18 is housed in a wiring 1428.

In the conventional example as described above, the wiring groove 28 is formed by forming the conductor of the coil using thin film technology or thick film technology.
The dimensions of the device can be reduced, thereby improving transmission characteristics and crosstalk characteristics.

[Problems to be Solved by the Invention] Generally, when a conductor provided in a magnetic material is energized, inductance is inevitably generated. For example, in the conventional example described above, when a signal is transmitted and received at 1JjT between the thin film conductor 18 and the connecting conductor 24, the through hole 2 of the magnetic core lO
2, current flows through it and inductance is generated.

Here, assuming a ferrite bead model as shown in Fig. 5, calculate the inductance.0 Length intersection of cylindrical ferrite 30 = 4.5 mm, diameter D
= 3.5 mm, and if the conductor 32 is passed through the ferrite 30 in the longitudinal direction and energized, approximately 1.21LH
An inductance of .

In the conventional example described above, through holes are used at both ends of the thin film conductor 18, so inductance occurs at two locations in total.

Since this inductance does not contribute to signal transmission, it acts as a leakage inductance.

Due to the existence of such leakage inductance, conventionally there is a problem in that it is difficult to reduce the leakage inductance when looking at the coil as a whole.

The present invention was developed in view of the above problems, and an object of the present invention is to provide a rotary transformer with good characteristics that can reduce leakage inductance.

[Means for Solving the Problems] The present invention provides a rotary transformer in which a coil conductor is formed on the facing side of a jujube magnetic core and a second magnetic core: Formed on each coil conductor member of the magnetic core. Two conductor pieces are molded with non-magnetic material into the through holes that communicate with the opposing surfaces of the magnetic core, and both ends of the coil conductor are attached to the ends of the opposing surfaces of both conductor pieces. It is characterized in that it is configured such that the signals from each coil conductor are connected to the opposite side of the magnetic core through the conductor piece.

[Function] According to the present invention, a non-magnetic material is interposed between the magnetic core and the conductor piece that draws out the coil conductor of the magnetic core to the four sides of the magnetic core. The magnetic effect on the magnetic core due to energization of the conductor piece is reduced by the non-magnetic material.

[Examples] - Examples of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an embodiment of the invention. This example is for a two-channel case, and (A) in the figure shows a part of the rotor or stator, and CB) shows the end of the coil seen from the arrow in the figure (^). It is an enlarged view of.

In these figures, the magnetic core 50 is formed into a disk shape of, for example, NiZn polycrystalline ferrite. First, alumina (Ant Ox
The insulating rfj 51 is formed of an insulating material such as ).

Two spiral thin film coils 52 and 54 are formed concentrically from copper or the like at this point. Further, short rings 56, 58, 60 are formed of copper or the like between the coils 52, 54 and the ends of the magnetic core 50, respectively, as required.

Next, as shown in FIG. 5B, both ends 62.degree. 64 of the spiral pJ membrane cocoil 52 or 54) are connected to conductor wires 66 and 68 coated with glass M, respectively. That is, the conductor wires 66 and 68 do not come into direct contact with the magnetic core 50, but indirectly come into contact with the magnetic core 50 via the glass layer 70.

Next, with reference to FIG. 2, a method of manufacturing both end portions of the thin film coils 52 and 54 shown in FIG. 1(B) will be described.

First, as shown in FIG. 5A, a round through hole 72 is formed at a corresponding position of the magnetic core 50. Next, with an appropriate jig, a round through hole 72 is formed at an appropriate position of the through hole 72. A conductor line 66,68 is positioned along. Then, a bar glass (not shown) is stuffed into the gap between these conductor wires 66, 68 and the magnetic core 50, and the glass 8 is heated and melted.
70 is formed. As a result, the conductor wires 66 and 68 are glass-sealed within the through hole 72 of the magnetic core 50, as shown in FIG.

Next, after the conductor wires 66 and 68 are glass-sealed and attached as described below, the surface of the magnetic core 50 facing the gap is polished to a mirror finish, and then the insulating layer 51 is polished as described above by a method such as sputtering. It is formed as shown in C). This insulating layer 51 is formed of, for example, alumina (AJltOx) or the like to a thickness of about 171 m. In addition, the magnetic core 5
If 0 is made of a material with high electrical resistance such as NiZn ferrite, such an insulating layer 51 is not necessarily required.

Next, as shown in M Ig (D), conductor wire 66°6
The alumina (Al2O) attached to the surface 8 is removed, and a thin copper layer s74 is formed by sputtering, plating, vapor deposition, etc., as shown in FIG. Then, necessary patterning is performed using a well-known photolithography technique, unnecessary portions are removed, and spiral thin film coils 52 and 54 are formed. Furthermore, an insulating insulation layer is formed on the tf1M coil 52, 54, if necessary. Note that at this time, short rings 56, 58, and 60 are also formed as necessary.

As described above, the conductor wires 66, 68 are held by the glass layer 70 at positions separated from the magnetic core 50, which is a magnetic material.

Next, an example of the characteristics of the transformer according to the above embodiment will be explained with reference to Table 1.

The rotary transformer of the example in this table is.

It is a 2-channel type with 3 turns on the rotor side and 6 turns on the stator side. The rotary transformer of the comparative example is similar to the conventional example described above, in which both ends of a spiral thin film coil are drawn out to the back side of the magnetic core through two through holes. Furthermore, the gap width between the rotor and the stator was 75 m.

Table 1 As is clear from Table 1, this example has (1) extremely small leakage inductance and (2) extremely small leakage inductance compared to the comparative example.
) has the advantages of large coupling coefficient, (3) large transmission efficiency, (high 0 resonance frequency, and (5) small crosstalk.

Next, another embodiment of the present invention will be described with reference to FIG. Note that the same reference numerals are used for the same components as in the embodiment described above.

This embodiment differs from the above-described embodiments in that the coil conductor is provided in the groove as in the conventional example shown in FIG. In FIG. 3, on the surface of the magnetic core 50 facing the gimlet,
First, ring-shaped grooves 80 are formed concentrically. This one
III80 is formed to a depth of, for example, about 20 to 30 pm. The conductor wires 66 and 88 are held at corresponding positions within the groove 80 by the glass layer 0, respectively.

The thin film coil 82 is formed in a spiral shape within the groove 80 by a film forming technique, and its ends are connected to the conductor wires 66, 68 within the groove 80. Furthermore, on the am coil 82.

Insulation is maintained by filling the groove 80! 1s84 is formed.

In this example, the above-mentioned quantity + 1t161-20140
It can be considered that the present invention is applied to the rotary transformer disclosed in Publication No. 5, and in addition to the effects of the embodiments described above, it is also possible to reduce insertion loss and crosstalk between channels.

Note that the present invention is not limited to the above embodiments, and various materials, manufacturing methods, shapes and dimensions may be applied.For example, in the above embodiments, the conductor wire is connected to the magnetic core 50. It may be sealed with glass, or may be sealed with various other non-magnetic materials such as ceramic, resin, adhesive, etc. In addition to the above-mentioned NiZn ferrite, the magnetic core may be
It may be formed of a metal soft magnetic material such as MnZn ferrite, sendust, or permalloy, an amorphous magnetic material, or a laminate thereof.

[Effects of the Invention] As explained above, according to the present invention, since a non-magnetic material is interposed between the conductor piece that connects the coil conductor to the back side of the magnetic core and the magnetic core, leakage of the transformer is reduced. This has the effect that inductance can be reduced and a rotary transformer with good characteristics can be provided.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway perspective view showing the main parts of one embodiment of the present invention, PJSz is an explanatory diagram showing an example of the assembly process of the embodiment shown in Fig. 3, and Fig. 3 is a perspective view of another embodiment. FIG. 4 is an explanatory diagram showing a conventional example, and FIG. 5 is an explanatory diagram of leakage inductance in the conventional example. SO-...Magnetic core, 51...Insulating layer, 52.54-@
Membrane coil, 56, 58.60--Short ring, 6
6.68... Conductor wire, 70-... Glass layer, 72-...
・Through hole. Patent applicant Kunio Kakiki, representative of Victor Japan Co., Ltd. Figure (B) Figure (F) Figure 4II (Al +8> Q

Claims (1)

[Claims] In a rotary transformer in which a coil conductor is formed opposite to each other on the facing side of a first magnetic core and a second magnetic core, a magnetic core formed in each coil conductor member of the magnetic core. Two conductor pieces are molded with non-magnetic material into the through-holes that communicate with the opposite side of the coil, and both ends of the coil conductor are connected to the ends of the two conductor pieces on the opposite side. A rotary transformer characterized in that a signal from each coil conductor is led out to the opposite side of a magnetic core through the conductor piece.