JPH08330161A - Rotary transformer - Google Patents

Abstract

PURPOSE: To provide a rotary transformer in which the deterioration of characteristics is prevented without causing any crosstalk while facilitating the connection of coil terminal. CONSTITUTION: In a rotary transformer where a plurality of coils 2 corresponding, in number, to the number of channels are arranged on the opposing surfaces of a pair of magnetic core 1, a through hole 5 is made through the outer wall face 1b from the opposing face 1a of at least one magnetic core 1 in order to lead out the ends 2a, 2b of the coil 2. A printed wiring board 8 for connecting the ends 2a, 2b of the coil 2 electrically is fixed to the vicinity of the through hole 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary transformer used in rotary magnetic head devices such as video tape recorders and digital audio tape recorders.

[0002]

2. Description of the Related Art A rotary transformer is a connecting means for transmitting a signal obtained by a rotary magnetic head provided on the rotary side of a rotary magnetic head device such as a video tape recorder or a digital audio tape recorder to a fixed side circuit. Widely used.

In this type of rotary transformer, a so-called flat rotary transformer in which a pair of disk-shaped magnetic cores are arranged to face each other and a pair of cylindrical magnetic cores are arranged to face each other inside and outside the motor shaft. There are so-called vertical rotary transformers, each of which has a pair of magnetic cores, and a coil is arranged in each winding groove provided according to the number of channels on the opposing surfaces of these magnetic cores. There is.

For example, in a vertical rotary transformer, a pair of cylindrical outer magnetic cores and inner magnetic cores having different outer diameters are arranged coaxially inside and outside to face each other. The inner magnetic core is, for example, a stationary side, that is, a stator, and the outer magnetic core is a rotating side, that is, a rotor. Of course, the reverse is also true. Further, a plurality of annular coils are arranged in the winding grooves respectively provided on the facing surfaces of these magnetic cores in accordance with the number of channels.

In such a rotary transformer, a magnetic head device connected to one magnetic core and a reproducing circuit connected to the other inner magnetic core are connected by electromagnetic coupling between a pair of magnetic core coils. Then, video signals, digital audio signals, etc. are transmitted.

By the way, the cylindrical outer magnetic core 10 is formed.
1 is an outer magnetic core 101, as shown in FIGS.
On the inner peripheral surface 101b which is the opposite surface of the coil 102, the winding groove 103 for arranging the coil 102, the short ring groove 104 for arranging the short ring, and the terminals 102a, 102 of the coil 102.
A lead-out groove 105 for leading out b is provided.

The winding groove 103 is provided for arranging, for example, a coil 102 having a circular ring shape in advance or a coil 102 simply made of a wire, and the inner peripheral surface 101 of the outer magnetic core 101.
The groove is formed in b as a groove having a substantially U-shaped cross section.
The winding grooves 103 are provided in the same number as the number of channels required at a predetermined interval along the motor axial direction of the outer magnetic core 101.

On the other hand, the short ring groove 104 is a short ring made of an insulating wire or the like (not shown) for preventing mutual interference between the coils 102 arranged in the winding groove 103, noise generation, and inductance change. No.) is provided and is provided between the winding grooves 103, respectively. This short ring groove 104 is also the winding groove 1
Like 03, it is formed in an annular shape as a groove having a substantially U-shaped cross section.

The lead-out groove 105 is formed by connecting the ends 102a, 1 of the coil 102 arranged in each winding groove 103.
02b is led out to the drum side, and these winding grooves 10
It is provided along a motor axial direction orthogonal to the winding groove 103 from a part of the magnetic core 101 to one end (mounting side to the drum) of the magnetic core 101. That is, the lead-out groove 105 is formed on the inner peripheral surface 101 b of the outer magnetic core 101 as a long vertical groove formed from one end portion on the upper side of the outer magnetic core 101 to one end portion on the lower side.

The bottom of the outer magnetic core 101,
That is, as shown in FIG. 9, a printed wiring board 108 is often attached in a ring shape to the end of the lead-out groove 105. In addition, the terminal 102 of the coil 102
The a and 102b are guided and led out to the lead-out groove 105, and are connected to the land portion 109 of the printed wiring board 108.

[0011]

However, the performance of the rotary transformer depends on the facing area of the pair of magnetic cores. That is, in the examples shown in FIGS. 8 and 9, there is a problem that if the area of the inner peripheral side 101b of the outer magnetic core 101 is reduced, the required performance of the rotary transformer cannot be obtained.

However, in the conventional rotary transformer, since the elongated groove 105 extending from one end on the upper side to one end on the lower side is provided on the inner peripheral side 101b of the outer magnetic core 101, the channel is formed. The greater the number, the more the inner peripheral surface 10 of the outer magnetic core 101.
The area of 1a is reduced, and the required performance of the rotary transformer cannot be obtained.

Particularly in recent years, since there is a strong demand for downsizing and multi-channelization of a rotary transformer due to a demand for downsizing of a drum and the like, providing a large number of lead-out grooves 105 makes it impossible to obtain a required rotary transformer performance. There is a high risk.

For this reason, lead wires for two channels are usually provided in the same lead-out groove 105. There is a method of putting wirings of a plurality of channels into one lead groove 105, but the same lead groove 105 is used.
This is because the problem of crosstalk occurs between the lead wires wired in the.

However, for example, in the case of 8 channels, four lead-out grooves 105 are required, and the number of lead-out grooves 101 is increased, and the problem of crosstalk is completely eliminated. It doesn't mean that it can be solved.

On the other hand, in the assembly of a vertical type rotary transformer in which the magnetic core is integrated, the coil 102 is wound in an annular shape in advance, and the coil 102 is deformed to face the outer magnetic core 101 from the one end direction. (Inner surface) 101
In some cases, the method may be adopted in which the wire is inserted into the wire b, wired in the winding groove 103, and unfolded there.

However, in a rotary transformer having a large number of channels, it is not easy to work by wiring the annular coil 102 in the winding groove 103 on the other end side opposite to the insertion side and widening it. there were.

Incidentally, the recent demand for a compact and multi-channel rotary transformer has an influence on the work of assembling the rotary transformer.

Therefore, according to the present invention, in a rotary transformer in which a plurality of coils corresponding to the number of channels are arranged on the facing surfaces of a pair of magnetic cores, the characteristics thereof are not deteriorated and the problem of crosstalk occurs. It is an object of the present invention to provide a rotary transformer in which the terminals of the coils can be easily connected without any trouble.

[0020]

A rotary transformer according to the present invention is proposed in order to achieve the above-mentioned object, and a winding formed on the opposing surfaces of a pair of magnetic cores according to the number of channels. A rotary transformer having a coil arranged in a groove is characterized in that a through hole for penetrating an end of the coil from the facing surface of at least one magnetic core to the outer wall surface is provided.

Further, the pair of magnetic cores is characterized in that they are a cylindrical outer magnetic core and an inner magnetic core arranged coaxially inside and outside.

Further, the through hole is formed at a position corresponding to the winding groove.

Further, one or more through holes are formed in at least one magnetic core.

Further, it is characterized in that through holes are formed on the upper side and the lower side of the outer magnetic core, respectively.

Further, a printed wiring board for electrically connecting the ends of the coil is attached to the vicinity of the through hole of the magnetic core.

[0026]

In the rotary transformer according to the present invention, since the through hole for penetrating the end of the coil through the magnetic core is provided, a large number of long lead grooves corresponding to the number of channels are formed on the facing surface of the magnetic core. Unlike the conventional rotary transformer for forming the magnetic core, the area of the facing surface of the magnetic core is not reduced. Therefore, even if the number of channels increases, the area of the facing surface of the magnetic core can be increased.

Further, when the end of the coil arranged in the winding groove is led out, it can be led out directly from the through hole to the outer wall surface of the magnetic core. Therefore, as compared with the conventional rotary transformer in which the magnetic core is led out from one end, the coil end can be easily wired.

When the through hole is formed at a position corresponding to the winding groove, the end of the coil is led out so as to be continuous with the winding groove.

Further, when the through holes are formed on the upper side and the lower side of the magnetic core, the ends of the plurality of coils according to the number of channels are not concentrated in one place. That is, the coil on the upper end side is
On the other hand, the coils on the lower end side are respectively wired from the through holes on the lower side.

Further, in the case where a printed wiring board for connecting the terminal of the coil to the wiring provided on the apparatus side is attached in the vicinity of the through hole, the terminal of the coil can be easily and easily connected to the wiring provided on the apparatus side. It will be surely connected.

[0031]

EXAMPLES Specific examples to which the present invention is applied will be described below.

The present embodiment is an example in which a so-called vertical rotary transformer, in which cylindrical magnetic cores having different outer diameters are coaxially arranged inside and outside, is applied to a rotary magnetic head device. The vertical rotary transformer is of a so-called laminated type (sometimes referred to as "doughnut type") in which one-channel magnetic cores are laminated to form multiple channels, but in the present embodiment, Description will be given based on a so-called integrated type which is widely used in terms of cost.

As shown in FIG. 1, the rotary magnetic head device comprises an upper rotary drum 21 and a motor 29 for rotating a lower fixed drum 22.

The motor 29 includes a stator 29b and a rotor 2
9a and the stator 29b has a motor shaft 23
Is provided.

The rotary drum 21 is attached to the motor shaft 23 and rotates together with the motor shaft 23. Further, the rotating drum 21 is provided with magnetic head devices 25, 25 for recording or reproducing on a magnetic tape. In addition, 26 is a bearing and 27 is a preload ring.

The rotary drum 21 and the fixed drum 22
Is connected to a magnetic head device connected to one of the magnetic cores and a reproducing circuit connected to the other magnetic core by electromagnetic coupling between a pair of magnetic core coils 2 to transmit a video signal or the like. A rotary transformer is installed.

In this rotary transformer, a cylindrical outer magnetic core 1 and inner cylindrical magnetic core 11 having different outer diameters are arranged coaxially inside and outside. That is, the outer magnetic core 1 is on the fixed side and the inner magnetic core 11 is on the rotating side.

These outer magnetic core 1 and inner magnetic core 11
Are formed by kneading a magnetic powder such as ferrite with a binder, hardening the mixture with a press, firing this, and polishing it.

The outer magnetic core 1 serves as a stator mounted on the fixed side, and as shown in FIGS. 2 and 3, the winding groove 3 for arranging the coil 2 on the cylindrical inner peripheral surface 1b. A short ring groove 4 for arranging the short ring and a through hole 5 for leading out the terminals 2a, 2b of the coil 2 are provided.

The winding groove 3 is provided, for example, in order to dispose the coil 2 which is previously formed into an annular shape or the coil 2 which is simply a wire rod, and the groove having a substantially U-shaped cross section on the inner peripheral surface 1b of the magnetic core 1. Are formed in an annular shape at equal intervals. This winding groove 3 is provided in the coil 2 according to the required number of channels.
The same number as the number of is provided along the direction of the motor shaft 23 at predetermined equal intervals. This embodiment is of a four-channel type, and the winding grooves 3 corresponding to these are formed.

On the other hand, the short ring groove 4 is a short ring (not shown) made of an insulating wire or the like for preventing mutual interference between the coils 2 arranged in the winding groove 3, noise generation, and inductance change. No.) is provided between the winding grooves 3. The short ring groove 4 is also formed in an annular shape as a groove having a substantially U-shaped cross section, like the winding groove 3 described above.

In particular, a through hole 5 is provided in the outer magnetic core 1. The through hole 5 is for directly leading the ends 2a and 2b of the coil 2 arranged in each winding groove 3 to the drum side, and as shown in FIGS. 2 and 3, inside the outer magnetic core 1. It is formed so as to penetrate the outer wall surface 1a from the surface 1b facing the magnetic core 11. From a different point of view, the outer magnetic core 1 penetrates from the outer peripheral surface (outer wall surface) 1a to the inner peripheral surface (opposing surface) 1b so as to face each winding groove 3 so as to correspond to each winding groove 3. Has been formed.

Here, the through-holes 5 of this embodiment are formed in two slit-shaped ones with one end of the outer magnetic core 1 cut out. In addition, the above two through holes 5 and 5
Are formed on the upper side (front side in FIG. 2) and the lower side (rear side in FIG. 2) respectively, and the through hole 5 on the upper side and the through hole 5 on the lower side are located at about 180 degrees. It is formed by shifting. The length H of each of the slit-shaped through holes 5 is
2 is formed so as to be approximately 1/2 of the width H1 of the outer magnetic core 1.

In this way, the plurality of coils 2 provided along the motor shaft 23 are the coils 2 on the upper side.
This is because it is considered that there is a position suitable for each of the lower coil 2 and the coil 2 on the lower side, even if they are necessarily led to the device side. More specifically, the coil 2 on the upper end side of the outer magnetic core 1 in the direction along the motor shaft 23 is located closer to the coil 2 on the other end than the through hole 5 on the upper side.
The reason is that it is more workable to wire the through holes 5 on the lower side. Further, it is because the terminals 2a and 2b of the plurality of coils 2 are not concentrated in one place and crosstalk is not generated.

In this embodiment, the through holes 5 and 5 are about 1
It was formed by shifting the position by 80 degrees, but if the number of channels is increased, for example, about 120
They may be formed by shifting them one by one.

The through holes 5 are preferably as small as possible. In particular, the through hole 5 in the inner peripheral surface 1b of the outer magnetic core 1 is preferably as small as possible. This is because the performance of the rotary transformer depends on the facing area of the magnetic cores 1 and 11. That is, in the outer magnetic core 1, it depends on the area of the inner peripheral surface 1 b which is the surface facing the inner magnetic core 11.

Therefore, when the number of channels is large,
As shown in FIG. 2 and FIG. 3 described above, one end of the outer magnetic core 1 may be cut out to form a slit shape, but as shown in FIG. 4 and FIG. It can be said that it is preferable to form a rectangular shape without cutouts. When the rectangular shape shown in FIGS. 4 and 5 is formed, the mechanical strength is higher than that of the cutouts of the examples shown in FIGS. 2 and 3. In the example shown in FIGS. 4 and 5, the through hole 5 is continuous in correspondence with the two winding grooves 3 and 3 on the lower side of the outer magnetic core 1 as shown in an enlarged manner in FIG. Is formed in this way.

Further, as shown in FIGS. 6 and 7, the through hole 5 may be formed by completely cutting out from the one end of the upper side of the outer magnetic core 1 to the one end of the lower side thereof. good.
Then, in order to make the through hole 5 formed in the inner peripheral surface 1b of the outer magnetic core 1 as small as possible, that is, in order to increase the area of the inner peripheral surface 1b of the outer magnetic core 1, the through hole 5 is formed. May be formed such that the outer peripheral surface 1a is larger than the inner peripheral surface 1b of the outer magnetic core 1 (a> b in FIG. 7).

The outer peripheral surface 1a of the outer magnetic core 1 may be formed to be larger than the inner peripheral surface 1b (a> b) in the above-described examples shown in FIGS. 2 and 3. Four
Of course, it may be applied to the example shown in FIG. Further, as shown in FIG. 3, a printed wiring board 8 is formed on the outer peripheral surface 1 a of the outer magnetic core 1 in the vicinity of the through hole 5. The printed wiring board 8 is for connecting the terminals 2a and 2b of the coil 2 to the wiring provided on the device side, and is formed in the vicinity of the through holes 5 and 5, respectively.

The width H3 of the printed wiring board 8 is formed to be substantially the same as the length H2 of each slit-shaped through hole 5 (H2 = H3).

Further, the end portion 8a of the printed wiring board 8 is
Are formed so as to be located in the vicinity of the through hole 5. Further, terminals 8a and 8b for connecting the terminals 2a and 2b of the coil 2 to the wirings provided on the device side are provided at the ends of the printed wiring board 8.

The terminals 8a of each printed wiring board 8 are
8b is a terminal 2a of the coil 2 corresponding to the number of channels,
It is formed to have the same height corresponding to each height of 2b. In this embodiment, the coil 2 on the upper end side is wired from the through hole 5 on the upper side, and the coil 2 on the lower end side is wired from the through hole 5 on the lower side. This is because it is possible to provide wiring that is continuous with each winding groove 3 depending on the height, and to facilitate the derivation of the terminals 2a and 2b of the coil 2.

Since this embodiment has the above-mentioned structure, the area of the inner peripheral surface 1b of the outer magnetic core 1 can be made larger than that of the conventional rotary transformer having a large number of long vertical grooves. . That is, even if the number of channels is large, it is not necessary to form a large number of grooves on the inner peripheral surface 1b of the outer magnetic core 1, and the reduction of the area of the inner peripheral surface 1b of the outer magnetic core 1 can be minimized. it can.

Therefore, even if the number of channels is large, the reduction in the area of the facing surface of the magnetic core 1 can be minimized, so that the characteristics as a rotary transformer can be improved.

This is especially true in recent years because the size of rotary transformers is small and there is a strong demand for multi-channels. Therefore, the above configuration is extremely effective in the future technical development of small-sized multi-channel rotary transformers.

On the other hand, the recent demand for a compact and multi-channel rotary transformer has an influence on the work of assembling the rotary transformer. However, the rotary transformer of this embodiment can reduce the assembling work even in the case of such a small size and a large number of channels.

That is, the coil 2 arranged in the winding groove 3
When the terminals 2a and 2b of 1 are led out, they can be led out directly from the through hole 5 to the outer peripheral surface 1a of the outer magnetic core 1. Since the through holes 5 are formed on the upper side and the lower side of the outer magnetic core 1 respectively, and the upper through holes 5 and the lower through holes 5 are formed at different positions, the number of channels is increased. The terminals 2a and 2b of the plurality of coils 2 according to the above are not concentrated in one place.

A printed wiring board 8 for connecting the terminals 2a and 2b of the coil 2 to the wiring provided on the apparatus side is attached in the vicinity of the through holes 5, and the width H3 of each of the slit-shaped through holes 5 is provided. It is formed to have substantially the same width as the length H2 (H2 = H3). Therefore, although the present embodiment has four channels, the two channels on the upper end side are continuous with the winding groove 3 from the upper through hole 5, and the two channels on the lower end side are continuous with the winding groove 3 from the lower through hole 5. Is guided,
Each can be easily wired.

Moreover, the length H2 of each through hole 5 is formed to be approximately 1/2 of the width H1 of the outer magnetic core 1. Further, the terminals 8a and 8b of each printed wiring board 8 are
Are terminals 2a, 2b of the coil 2 according to the number of channels
Are formed at the same height corresponding to each height. Therefore, the terminals 2a and 2b of each coil 2 are led out from the inside to the outside with the height of each of the four channels unchanged, that is, without changing the height position. Then, the terminals 8a and 8b of the printed wiring board 8 are easily and surely connected. Therefore, there is no problem of occurrence of crosstalk.

By the way, in the assembly of a vertical type rotary transformer having an integrated magnetic core, the coil 2 is preliminarily wound in an annular shape, and the coil 2 is deformed to face the outer magnetic core 1 from the one end direction. A method may be adopted in which the wire is inserted into the (inner peripheral surface) 1b, wired in the winding groove 3, and unfolded there.

Therefore, the terminals 2 of each of the plurality of coils 2 are
Even if the above-mentioned connection method is adopted, the present embodiment is performed because the terminals a and b are led out from the inside without changing the height positions of a and 2b and connected to the terminals 8a and 8b of the printed wiring board 8. According to the example, the connection is easy and reliable.

The coil 2 and the terminals 2a, 2b are connected to each other by soldering or the like. Also, each coil 2
The terminals 2a and 2b are formed without changing the height position, but in order to smoothly and reasonably perform such connection, the through hole 5 is formed to have such a horizontal U-shape,
The end side corner of the through hole 5 may be cut or polished into a circular arc cross section.

In this respect, the conventional rotary torque is formed as a continuous drawing groove 105 from one end portion on the upper side to one end portion on the lower side of the outer magnetic core 101, as shown in FIGS. 8 and 9. And is connected to the printed wiring board 108 provided at one end. However, even if the coil 102 on the upper side needs the long lead-out groove 101, the coil 2 on the lower side does not need such a long lead-out groove 101. Further, when the area of the inner peripheral side 101b of the outer magnetic core 101 is reduced, there is a problem that required performance of the rotary transformer cannot be obtained.

On the other hand, in the present embodiment, the through holes 5 on the upper side and the through holes 5 on the lower side are formed so as to be shifted by about 180 degrees, and are necessary for wiring the terminals 2a, 2b of each coil 2. Through holes 5 and 5 are formed only in these portions. Further, even when the terminals 2a and 2b of the coils 2 are led out from the inside of the outer magnetic core 1 to the outside, on the other hand, a plurality of coils 2 are preliminarily wound in an annular shape and the coils 2 are deformed. On the other hand, the method of inserting from the end portion direction into the facing surface (inner peripheral surface) 1b of the outer magnetic core 1 and wiring to each winding groove 3 and expanding the winding groove 3 also provides easy and reliable connection.

Next, a method of forming the through hole 5 according to this embodiment and the assembling of the rotary transformer will be briefly described.

Generally, magnetic powder such as ferrite has been conventionally pressed using a die to form a cylindrical magnetic core,
Next, this is baked at a high temperature, and then the winding groove 3 and the like are ground to form it.

Therefore, the outer magnetic core 1 provided with the through hole 5 of this embodiment is also used for the above-mentioned mold (not shown).
Can be easily manufactured into a shape defined by.

However, the core may be distorted or deformed due to a difference in heat conduction during firing. In addition, the winding groove 3, the through hole 5, and the like have a large amount of deformation due to firing, and in some cases, a considerable grinding allowance is required.

Therefore, in such a case, the winding groove 3 and the through hole 5 may of course be ground after firing. It is to be noted that the former example is suitable for a rectangular example in which one end portion of the example shown in FIGS. 4 and 5 is not cut out. Also, the latter example is suitable for FIGS.
As shown in FIG. 6, one end portion of the outer magnetic core 1 is cut out to form a slit shape, and the examples shown in FIGS. 6 and 7.

Next, as shown in FIG. 1, the outer magnetic core 1 manufactured as described above is mounted after the inner magnetic core 11 is mounted, for example, on the rotating upper drum 21 with its position being restricted. The fixed side lower drum 22 is attached with its position regulated.

As a result, the pair of outer and inner magnetic cores 1 and 11 are arranged on the rotating side and the fixed side to face each other with a small gap, and the outer magnetic core 1 attached to the fixed side and the inner magnetic core attached to the rotating side. Video signals, digital audio signals, etc. are transmitted by electromagnetic coupling between the coils 2 of 11.

As described above, in the present embodiment, the pair of magnetic cores are the cylindrical outer magnetic core and the inner magnetic core arranged inside and outside the motor shaft with the center as the center. The present invention is applied to a so-called vertical rotary transformer arranged along an axis, but the present invention is also applied to a so-called flat rotary transformer in which a pair of disk-shaped magnetic cores are arranged to face each other. Is something that can be done. Further, in the present embodiment, the description has been given based on the integrated type which is widely used in terms of cost,
It can also be applied to a laminated type in which one-channel magnetic cores are laminated. Furthermore, although the outer magnetic core is provided with the through hole in the present embodiment, the inner magnetic core may be provided with the through hole.

[0073]

As is clear from the above description, in the rotary transformer according to the present invention, since the through hole for penetrating the end of the coil through the magnetic core is provided, the facing surface of the magnetic core is opposed. Unlike the conventional rotary transformer in which a large number of long lead-out grooves are formed, the area of the facing surface of the magnetic core is not reduced. Therefore, even if the number of channels is increased, the area of the facing surface of the magnetic core can be made large, so that the performance of the rotary transformer is not deteriorated.

Since the recent rotary transformer is small and there is a strong demand for multi-channels, such an effect is extremely effective in the future technical development of a compact and multi-channel rotary transformer.

When the end of the coil disposed in the winding groove is led out, it can be led out directly from the through hole to the outer wall surface of the magnetic core. Therefore, as compared with the conventional rotary transformer which is led out from one end of the magnetic core, the wiring of the end of the coil can be performed more easily. Therefore, in the method of assembling the rotary transformer, insertion of the coil or winding of the coil is facilitated, and the work of assembling the rotary transformer is reduced.

When the through hole is formed at a position corresponding to the winding groove, the end of the coil is led out so as to be continuous with the winding groove.

When the through holes are formed on the upper side and the lower side of the outer magnetic core, respectively, and the through holes on the upper side and the through holes on the lower side are formed at different positions,
Terminals of a plurality of coils according to the number of channels are not concentrated in one place. Therefore, there is no problem of occurrence of crosstalk.

Further, in the case where a printed wiring board for connecting the terminal of the coil to the wiring provided on the apparatus side is attached in the vicinity of the through hole, the terminal of the coil can be easily and easily connected to the wiring provided on the apparatus side. It will be surely connected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing a rotary transformer according to an embodiment of the present invention.

FIG. 2 is a perspective view showing an outer magnetic core that constitutes the rotary transformer according to the embodiment.

FIG. 3 is a perspective view showing an example in which a printed wiring board is provided in the vicinity of the through hole.

FIG. 4 is an enlarged perspective view showing another example of a through hole in the above embodiment.

5 is an enlarged perspective view of the through hole of FIG.

FIG. 6 is a perspective view showing still another example of the through hole in the above embodiment.

7 is an enlarged perspective view of the through hole of FIG.

FIG. 8 is a perspective view showing an outer magnetic core of a conventional rotary transformer.

FIG. 9 is a perspective view showing a state where a coil is wired to the outer magnetic core.

[Explanation of symbols]

 1 outer magnetic core 1a outer wall surface (outer peripheral surface) of the outer magnetic core 1b facing surface (inner peripheral surface) of the outer magnetic core 2 coils 2a, 2b coil end 3 winding groove 4 short ring groove 5 through hole 8 printed wiring board 8a, 8b Terminals of printed wiring board 11 Inner magnetic core 21 Upper drum 22 Lower drum 23 Motor shaft

Claims (6)

[Claims] 1. A rotary transformer in which a coil is arranged in a winding groove formed according to the number of channels on the facing surfaces of a pair of magnetic cores, wherein at least one of the magnetic cores penetrates the outer wall surface from the facing surface. A rotary transformer having a through hole through which a terminal of a coil is led out. 2. The rotary transformer according to claim 1, wherein the pair of magnetic cores are a cylindrical outer magnetic core and an inner magnetic core arranged coaxially inside and outside. 3. The rotary transformer according to claim 2, wherein the through hole is formed at a position corresponding to the winding groove. 4. The rotary transformer according to claim 3, wherein one or more through holes are formed in at least one of the magnetic cores. 5. The rotary transformer according to claim 4, wherein the through holes are formed on the upper side and the lower side in the axial direction of the magnetic core. 6. The rotary transformer according to claim 5, wherein a printed wiring board for electrically connecting the ends of the coil is attached in the vicinity of the through hole of the magnetic core.