JPH07201611A - Rotary transformer - Google Patents

Abstract

PURPOSE:To provide a rotary transformer in which the distributed capacitance is reduced significantly between the turns of coil while increasing the self resonance frequency and enlarging the frequency bandwidth. CONSTITUTION:The rotor section 1 and the stator section 2 comprise, respectively, base bodies 10, 20 and coils 11-17, 21-27. The base bodies 10, 20 have at least one faces 100, 200 opposing each other through a gap G. The coils 11-17, 21-27 are embedded closely to the opposing faces 100, 200 of the base bodies 10, 20 so that the coils rotate around a rotational axis. At least one of the rotor section 1 or the stator section 2 belongs to identical channel and includes predetermined number of turns of coils (11, 13, 14, 16, 17) and (21, 23, 24, 26, 27) and air gap grooves 41, 51, 52 provided between the turns of coils (11, 13, 14, 16, 17) and (21, 23, 24, 26, 27).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a rotary transformer.

[0002]

2. Description of the Related Art A rotary transformer has been widely known as a device for transmitting signals between a rotating device and a stationary device in a non-contact state. The main applications are:
In the signal transmission means for transmitting the signal read by the rotary head of the video tape recorder to the stationary side circuit device, or for transmitting the signal written from the stationary side circuit device to the rotary head, or in various control devices or detection devices, A signal transmission means between the rotation sensor and the stationary circuit device can be mentioned.

The rotary transformer includes a rotor portion and a stator portion, and exchanges signals by electromagnetic coupling between the rotor portion and the stator portion. Various types have been proposed and put to practical use. Have been served. Among them, what is called a laminated rotary transformer is small in size, highly reliable, and rich in mass productivity. Such a laminated rotary transformer is formed by the laminated technique disclosed in, for example, Japanese Patent Laid-Open No. 3-159206.

In the laminated rotary transformer, the base body includes a magnetic portion and an annular non-magnetic insulating portion embedded in the magnetic portion, and the coil is embedded in the non-magnetic insulating portion. The coil of the same channel is wound multiple times inside the non-magnetic insulating part in order to obtain the required transformation ratio.

[0005]

However, because of the structure in which the coil is wound and embedded in the non-magnetic insulating portion a plurality of times, distributed capacitance is generated between the coil turns due to the dielectric constant of the substrate. This distributed capacitance causes a problem that the self-resonant frequency becomes low and the frequency band becomes narrow. When nonmagnetic ferrite is used as a typical material of the nonmagnetic insulating portion, the relative dielectric constant εs reaches 14 to 16.

An object of the present invention is to provide a rotary transformer which performs a signal transmission by coupling a transformer between a rotor portion and a stator portion in the shortest distance. Another object of the present invention is to provide a rotary transformer having a transformation ratio according to the number of coil turns.

Still another object of the present invention is to provide a rotary transformer in which the distributed capacitance between coil turns is remarkably reduced, the self-resonant frequency is increased, and the frequency bandwidth is expanded by the air gap groove.

Still another object of the present invention is to provide a rotary transformer having excellent electric insulation and high magnetic efficiency.

Still another object of the present invention is to provide a rotary transformer which prevents oxidation of the coil through the gap groove and improves reliability.

Still another object of the present invention is to provide a rotary transformer in which the magnetic portion is not cut by the air gap groove and the magnetic efficiency is not sacrificed.

[0011]

In order to solve the above-mentioned problems, a rotary transformer according to the present invention comprises a rotor section,
A stator part, and each of the rotor part and the stator part has a base body and a coil,
Each said substrate having at least one opposing surface,
The opposed surfaces are opposed to each other with a space, and each of the coils is embedded near the opposed surface of the base so as to rotate around the rotation axis, and at least one of the rotor portion and the stator portion. Includes a coil that belongs to the same channel and is wound a plurality of times, and a void groove, and the void groove is provided in the base between turns of the coil.

In general, the base body includes a magnetic portion and a non-magnetic insulating portion, the non-magnetic insulating portion is embedded in the magnetic portion and is provided in an annular shape around the rotation axis. The coil is embedded in the non-magnetic insulating portion, and the void groove is provided in the non-magnetic insulating portion. Under this structure, the void groove preferably has a depth that opens in the facing surface and ends inside the non-magnetic insulating portion.

[0013]

Each of the rotor portion and the stator portion has a base body and a coil, and each base body has at least one facing surface, and the facing surfaces face each other with a space therebetween. Since the coil is embedded near the facing surface of the base so as to rotate around the rotation axis, both coils can be transformer-coupled at the shortest distance, and signal transmission can be performed between the rotor part and the stator part.

Since at least one of the rotor portion and the stator portion belongs to the same channel and includes a coil wound a plurality of times, a rotary transformer having a transformation ratio according to the number of coil windings can be obtained.

At least one of the rotor portion and the stator portion includes a void groove, and the void groove is provided in the base between the turns of the coil. Therefore, the relative permittivity is approximately between coil turns forming the same channel. A layer of one void groove is formed. Therefore, the distributed capacitance between the coil turns is significantly reduced, the self-resonance frequency is increased, and the frequency bandwidth is expanded.

The base includes a magnetic portion and a non-magnetic insulating portion, the non-magnetic insulating portion is embedded in the magnetic portion and is provided in an annular shape around the rotating shaft, and the coil is the non-magnetic portion. In the case of a structure in which the void groove is embedded in the insulating portion and provided in the non-magnetic insulating portion, the coils are electrically insulated by the electric insulating characteristic of the non-magnetic insulating portion, The magnetic flux generated by the coil current flows through the magnetic portion around the non-magnetic insulating portion. Therefore, a rotary transformer having excellent electric insulation and high magnetic efficiency can be obtained. In addition, since the coil is buried in the non-magnetic insulating portion in spite of the presence of the void groove, oxidation of the coil through the void groove can be prevented and reliability can be improved.

Further, under the above structure, when the void groove has a depth which opens in the facing surface and ends inside the non-magnetic insulating portion,
Since the magnetic portion is not cut by the void groove, the magnetic efficiency is not sacrificed.

The present invention can be applied to various types of rotary transformers. One application example is that the facing surface of the base body is in the axial direction of the rotating shaft to form a rotating plane,
It is a rotary transformer of the type in which the coil wound a plurality of times is distributed in the rotational diameter direction. In this type of rotary transformer, the coils wound a plurality of times may be further distributed in the axial direction of the rotary shaft.

In another application example, the facing surface of the base body constitutes a rotating peripheral surface, and the coils wound a plurality of times are distributed in the axial direction of the rotating shaft. It is a rotary transformer.

In any type of rotary transformer, the above-described operation is achieved.

[0021]

1 is a partially cutaway perspective view of a rotary transformer according to the present invention, and FIG. 2 is a partially enlarged sectional view of a coil coupling portion. The rotary transformer according to the present invention includes a rotor portion 1 and a stator portion 2. Reference numeral 3 is a rotation axis. The rotating shaft 3 is coupled to the rotor unit 1. The rotor unit 1 has a base body 10 and coils 11 to 17. The stator portion 2 also has a base body 20 and coils 21 to 27. Each of the bases 10 and 20 of the rotor part 1 and the stator part 2 has at least one opposing surface 100, 2.
00, the facing surfaces 100 and 200 face each other with a gap G therebetween. The coils 11 to 17 and 21 to 27 of the rotor portion 1 and the stator portion 2 are embedded near the facing surfaces of the bases 10 and 20 so as to rotate around the rotating shaft 3 and to form an electromagnetic conversion portion with each other. Facing each other.

Referring to FIG. 2, the rotor unit 1 includes coils 11 belonging to the same channel and wound a plurality of times.
It includes 13, 14, 16, 17 and the void groove 41. The void groove 41 is provided in the base 10 between the turns 111 and 112, for example, when the coil 11 is taken out as a typical example. The stator portion 2 also belongs to the same channel and is wound a plurality of times with the coils 21 and 2.
3, 24, 26, 27 and void grooves 51, 52 are included. The void grooves 51 and 52 are, for example, as shown in FIG.
The base 20 is provided between 212 and 213.

The number of turns of the coils 11 to 17 and 21 to 27 is determined by the transformation ratio, the inductance value or the DC resistance value to be obtained. Therefore, it is not limited to the number of turns shown. Depending on the case, the coils 11 to 17 of either the rotor portion 1 or the stator portion 2
Or the case where 21 to 27 are unified in one turn is also included.

Generally, the substrates 10, 20 include magnetic portions 101, 201 and non-magnetic insulating portions 102, 202, and the non-magnetic insulating portions 102, 202 are magnetic portions 10.
It is embedded in Nos. 1 and 201, and is provided in an annular shape around the rotary shaft 3. The coils 11 to 17 and 21 to 27 are embedded in the non-magnetic insulating portions 102 and 202, and the gap groove 4
1, 51 and 52 are provided on the non-magnetic insulating portions 102 and 202. Under this structure, the void grooves 41, 51, 5
2 preferably has depths d1 and d2 that open into the facing surfaces 100 and 200 and end inside the non-magnetic insulating portions 102 and 202. The bases 10 and 20 may be wholly made of a non-magnetic insulating material although the inductance value is sacrificed. The magnetic parts 101, 201 can be made of a magnetic ferrite material, and the non-magnetic insulating parts 102,
202 can be composed of a non-magnetic ferrite material.

As described above, each of the bases 10 and 20 of the rotor portion 1 and the stator portion 2 has at least one facing surface 100 and 200, and the facing surfaces 100 and 200 are separated by the gap G when the rotor portion 1 rotates. And the coils 11 to 17 and 21 to 27 are embedded near the facing surfaces 100 and 200 of the bases 10 and 20 so as to rotate around the rotation axis 3, so that both coils (11 ~ 17) and (21-27) are transformer-coupled at the shortest distance, and both coils (11 and 21), (12 and 22). ． ． (17 and 27)
Signals can be efficiently transmitted between them.

Moreover, at least one of the rotor portion 1 and the stator portion 2 belongs to the same channel and is wound a plurality of times (11, 13, 14, 16, 17) or (21, 23, 24, 26, 27), a rotary transformer having a transformation ratio, an inductance value, and a DC resistance value according to the number of coil turns can be obtained.

At least one of the rotor portion 1 and the stator portion 2 includes the gap groove 41 or 51, 52, and the gap groove 4
1 or 51, 52 between the turns of the coil, for example FIG.
As shown in FIG. 3, the turns of the coil 21 (211 and 2
12), (212 and 213) or between the turns (111 and 112) of the coil 11 are provided on the base body 10 or 20 so as to rotate around the rotation axis 3, and thus the coils forming the same channel. A layer of void grooves 41 or 51, 52 having a relative dielectric constant of about 1 is formed between turns. Therefore, the distributed capacitance between the coil turns is significantly reduced, the self-resonance frequency is increased, and the frequency bandwidth is expanded.

The bases 10 and 20 are magnetic parts 101 and 20.
1 and the non-magnetic insulating portions 102 and 202, the non-magnetic insulating portions 102 and 202 are embedded in the magnetic portions 101 and 201 and are provided in an annular shape around the rotating shaft 3, and the coils 11 to 17 and 21. 27 are non-magnetic insulating portions 102, 2
In the case of the structure in which the non-magnetic insulating portions 102 and 202 are provided with the void grooves 41 or 51 and 52 embedded in No. 02, the electrical insulation characteristics of the non-magnetic insulating portions 102 and 202 cause electrical insulation between coil turns. At the same time, the magnetic flux generated by the coil current due to the non-magnetic characteristic is generated around the non-magnetic insulating portions 102, 202 and the magnetic portions 101, 20.
It flows through 1 as shown by the broken line φ. Therefore, a rotary transformer having excellent electric insulation and high magnetic efficiency can be obtained. Moreover, despite the presence of the void groove, the coil 11
˜17, 21 to 27 are buried in the non-magnetic insulating portions 102 and 202, therefore, the oxidation of the coils 11 to 17 and 21 to 27 through the void grooves 41, 51 and 52 is prevented, and the reliability is improved. be able to.

Further, with the above structure, the void grooves 41, 5
If the first and the second holes have a depth that opens in the facing surfaces 100 and 200 and ends inside the non-magnetic insulating portions 102 and 202, the magnetic portions 101 and 201 are not cut by the air gap grooves 41, 51, and 52, so that the magnetic There is no sacrifice in efficiency.

The void grooves 41, 51 and 52 are formed by a printing lamination method,
By manufacturing the substrates 10 and 20 in which the coils 11 to 17 and 21 to 27 are embedded by a sheet laminating method, a thin film laminating method, or a combination thereof, laser processing or ultrasonic processing is applied to the facing surfaces 100 and 200. Can be formed. No void groove is provided in the region overlapping the coil conductor leading out the coil in order to avoid cutting of the conductor. Therefore, the void grooves 41, 51, 52 are generally partially discontinuous corresponding to the coil conductor leading structure. Reference numeral 181,
Reference numerals 182 and 281 to 288 are terminal electrodes. These terminal electrodes 181, 182, 281-288 are coils 11-
17, 21 to 27 are conductively connected.

The present invention can be applied to various types of rotary transformers. 1 to 3, the opposing surfaces 100 and 200 of the bases 10 and 20 are in the axial direction of the rotary shaft 3 to form a plane of rotation, and the coils (11, 13, 1) are wound a plurality of times.
4, 16, 17), (21, 23, 24, 26, 27)
Constitutes a rotary transformer of a type in which is distributed in the rotational diameter direction.

FIGS. 4 and 5 show the facing surfaces 1 of the bases 10 and 20.
00 and 200 are in the axial direction of the rotary shaft 3 and constitute a plane of rotation, and the coils (11, 13, 14, 1) are wound a plurality of times.
6, 17), (21, 23, 24, 26, 27) are distributed in the rotational diameter direction, and also in the axial direction of the rotating shaft 3,
An example in which a plurality of turns are distributed is shown. Void groove 4
1, 51 are coils (11, 13, 14, 16, 17),
It is provided in the winding axis direction of (21, 23, 24, 26, 27).

6 and 7 show another application example. In this embodiment, the facing surfaces 10 of the substrates 10, 20 are
0 and 200 constitute a rotating peripheral surface, and the coils 21 to 24 and 11 to 14 wound a plurality of times are distributed in the axial direction of the rotating shaft 3.

In any type of rotary transformer, the above-described operational effects can be obtained.

[0035]

As described above, according to the present invention, the following effects can be obtained. (A) It is possible to provide a rotary transformer that performs signal transmission by performing transformer coupling between the rotor portion and the stator portion at the shortest distance. (B) It is possible to provide a rotary transformer having a transformation ratio according to the number of coil windings. (C) It is possible to provide a rotary transformer in which the distributed capacitance between coil turns is significantly reduced by the air gap groove, the self-resonant frequency is increased, and the frequency bandwidth is expanded. (D) A rotary transformer having excellent electric insulation and high magnetic efficiency can be provided. (E) It is possible to provide a rotary transformer with improved reliability by preventing oxidation of the coil through the void groove. (F) It is possible to provide a rotary transformer in which the magnetic portion is not cut by the air gap groove and the magnetic efficiency is not sacrificed.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of a rotary transformer according to the present invention.

2 is a partially enlarged cross-sectional view showing an enlarged coil coupling portion of the rotary transformer according to the present invention shown in FIG.

FIG. 3 is a partial plan view showing a configuration of a coil portion of the rotary transformer according to the present invention shown in FIG.

FIG. 4 is a partially cutaway perspective view showing another embodiment of the rotary transformer according to the present invention.

5 is a partially enlarged sectional view of a coil coupling portion of the rotary transformer according to the present invention shown in FIG.

FIG. 6 is a partially cutaway perspective view showing still another embodiment of the rotary transformer according to the present invention.

7 is a partially enlarged sectional view of a coil coupling portion of the rotary transformer according to the present invention shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotor part 2 stator part 10 base | substrate 20 base | substrate 11-17 coil 21-27 coil 41 void | gutter groove 51,52 void | gutter groove

Claims (6)

[Claims] 1. A rotary transformer including a rotor portion and a stator portion, wherein each of the rotor portion and the stator portion has a base and a coil, and each of the bases has at least one. And facing each other with an interval, and each of the coils is embedded near the facing surface of the base so as to rotate around the rotation axis. At least one of the stator parts is
A rotary transformer, which includes a coil that belongs to the same channel and is wound a plurality of times, and a gap groove, wherein the gap groove is provided in the base between turns of the coil. 2. The base includes a magnetic portion and a non-magnetic insulating portion, the non-magnetic insulating portion is embedded in the magnetic portion and provided in an annular shape around the rotation axis, and the coil is The rotary transformer according to claim 1, wherein the rotary groove is embedded in the non-magnetic insulating portion, and the void groove is provided in the non-magnetic insulating portion. 3. The rotary transformer according to claim 2, wherein the gap groove has a depth that opens in the facing surface and ends inside the non-magnetic insulating portion. 4. The substrate has a facing plane in which the facing surface is in the axial direction of the rotating shaft to form a rotating plane, and the coils wound a plurality of times are distributed in the rotating diameter direction. The rotary transformer according to 1, 2 or 3. 5. The rotary transformer according to claim 4, wherein the coils wound a plurality of times are distributed in the axial direction of the rotary shaft. 6. The substrate according to claim 1, wherein the facing surface constitutes a rotating peripheral surface, and the coils wound a plurality of times are distributed in an axial direction of the rotating shaft. The rotary transformer described in 3.