JP2656541B2 - Rotary transformer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary transformer which serves to transmit and receive signals between a rotating magnetic head and a stationary main circuit in a video tape recorder or the like. is there.

[Conventional technology]

Conventionally, various types of rotary transformers called a flat type and a coaxial type have been proposed. For example, there is one described in Japanese Utility Model Laid-Open No. 29603/1987. This rotary transformer has been required to be smaller and have higher performance. Higher performance in video tape recorders means miniaturization and multifunctionality and higher image quality.Replacing this higher performance with a rotary transformer results in multi-channel and lower transmission loss characteristics. It is necessary to form a rotary transformer having.

[Problems to be solved by the invention]

However, when trying to construct a multi-channel rotary transformer with the size of the rotating cylinder limited by the standards such as VHS and 8 mm video, it is necessary to secure the strength of the core and some degree of magnetic path, There was something that conflicted with the transformation. In addition, the ferrite core forming the rotary transformer is difficult to form with high dimensional accuracy, and is liable to crack, chip, or the like.

In view of the above, an object of the present invention is to provide a rotary transformer that achieves miniaturization and high performance.

[Means for solving the problem]

The present invention provides a cylindrical ferrite core having a circumferential groove formed on an inner peripheral surface and an outer peripheral surface (referred to as a center core).
And a cylindrical ferrite core (hereinafter referred to as an outer core) having a circumferential groove formed on an inner peripheral surface thereof and disposed with a predetermined gap outside the center core, and a circumferential groove formed on an outer peripheral surface. And a cylindrical ferrite core (referred to as an inner core) disposed inside the center core with a predetermined gap interposed therebetween. 1) Outer peripheral surface of the center core And a slit groove is formed in the inner peripheral surface in the axial direction, and the slit groove is formed such that the slit groove formed on the inside and the slit groove formed on the outside are linearly aligned in one radial direction sandwiching the thickness. No rotary transformer, 2) With respect to the slit grooves formed on the outer peripheral surface and the inner peripheral surface of the sensor core on the axial end surface of the center core, the same number or more radial directions as the slit grooves are formed. A rotary transformer having a notched groove extending therefrom; 3) a width of a slit groove formed on an outer peripheral surface of the center core and a notch groove formed on an axial end face of the center core corresponding to the slit groove. 4) In the rotary transformer having a different width, 4) In the rotary transformer according to 2), one notch groove of the center core is formed deeper than another notch groove, or is wider than the width of another notch groove. 5) The same number or more diameters as the number of slit grooves on the axial end surface of the outer core corresponding to the slit grooves formed on the inner peripheral surface of the outer core in the axial direction. 6) The rotary transformer according to 5), wherein one notch of the outer core is formed. The rotary transformer wherein the groove is formed deeper than the other notch groove or wider than the width of the other notch groove. 7) In the rotary transformers of 2) and 5), the center core and the outer 8) In the rotary transformer according to 5), the inner core and the outer core are adhered to the same base, and the outer core is provided with the outer core. 9) In the rotary transformer of 1) or 4), the slit grooves formed on the inner circumferential surface and the outer circumferential surface of the center core are respectively formed in the circumferential direction. In the rotary transformers 10) and 5), which are arranged at equal intervals, the slots formed on the inner peripheral surface of the outer core DOO grooves, a rotary transformer are respectively arranged at equal intervals in the circumferential direction.

[Action]

According to the present invention, a slit groove (a groove for leading out a lead wire of a winding) is formed on an outer peripheral surface and an inner peripheral surface of a center core, and the slit groove is formed on an outer peripheral surface. The slit groove and the slit groove formed on the inner peripheral surface are formed so as not to be aligned on a straight line in the radial direction with the thick portion interposed therebetween. This is because if the slit grooves formed on the outer peripheral surface and the slit grooves formed on the inner peripheral surface are aligned in a straight line in the radial direction with the thick part interposed therebetween, the center core may be damaged due to the problem of core strength. Becomes thicker. Therefore, the center core of the present invention is formed such that the slit groove formed on the outer peripheral surface and the slit groove formed on the inner peripheral surface are not aligned on a straight line in the radial direction across the thick part. In addition, miniaturization is achieved.

In addition, cutout grooves corresponding to the slit grooves formed on the outer peripheral surface and the inner peripheral surface are formed on the axial end surface of the center core of the present invention. The cutout groove is for drawing out a lead wire of a winding disposed in a circumferential groove on the outer peripheral surface and the inner peripheral surface of the core. Due to the presence of the notch groove, when the center core is bonded to the base, the lead wire of the winding can be pulled out from the bonding surface with the core base. In addition, not only the notched groove for leading out the lead but also an extra notched groove for positioning in bonding or leading out of the lead makes it easy to assemble.

In the center core of the present invention, the width of the slit groove formed on the outer peripheral surface is different from the width of the notch groove formed on the core end surface corresponding to the slit groove. This is because the core of the present invention is designed such that the outer peripheral surface of the core is polished to obtain a predetermined roundness in order to increase the dimensional accuracy, and then the other parts are processed with reference to the outer peripheral surface. Is going. Therefore,
When machining the outer peripheral surface, if the outer peripheral surface has a slit groove, it is difficult to obtain predetermined accuracy. Therefore, the slit groove on the outer peripheral surface is formed by processing later. Further, the notch groove on the end face of the core and the slit groove on the inner peripheral face are formed at the time of compression molding using a mold. Therefore, the slit groove on the inner peripheral surface and the notch groove corresponding to the slit groove are formed at the same size and at a predetermined position by a molding die. As the corn is formed by processing the outer slit groove,
Although the slit groove width can be formed to the same size as the slit groove formed on the inner periphery, the occurrence of formation position shift cannot be prevented. When this displacement occurs, it becomes difficult to lead the leads, and there is a problem that the leads are cut when the coil is assembled. In order to absorb this displacement, the notch grooves corresponding to the slit grooves on the outer periphery are set in advance to be wider than the width of the slit grooves.

Further, in the present invention, one of the notch grooves formed in the sesser core is formed deeper or wider than the other notch grooves. This is because the center core is used for positioning when machining a slit groove on the outer periphery.
That is, when slitting the outer periphery, the deep or wide notch groove is detected by a sensor, and the slit groove of the outer periphery is processed based on the notch groove. Further, the deep or wide cutout groove can be used as a reference when bonding the center core to the base or when routing the lead wire of the winding.

Further, in the present invention, in the axial end face of the outer core, notches extending in the radial direction by the same number or more than the number of the slit grooves corresponding to the slit grooves formed in the axial direction on the inner peripheral surface of the outer core. A groove was formed. In this method, the lead wire of the winding disposed in the circumferential groove of the outer core is drawn out of the slit groove by the notch groove. Due to the presence of the cutout grooves, when the outer core is bonded to the base, the lead wire of the winding can be drawn out from the bonding surface between the outer core and the base. Further, when the outer core and the inner core are bonded to the same base, a lead wire of a winding disposed on the inner core can be drawn out through the cutout groove of the outer core.

Further, in the outer core of the present invention, the fact that one of the notch grooves is made deeper or wider than the other is that the notched groove that is made deeper or wider is used as positioning. That's why. That is, the deep or wide cutout groove can be used as a reference when bonding the outer core to the base or when routing the lead wire of the winding.

By arranging the slit grooves at equal intervals, the stress distribution becomes uniform, the precision during compression molding by the mold is improved, and the processing allowance during processing is reduced. Is shortened. In addition, since the slit grooves are symmetrically arranged, the core shape has no directionality, and in order to simplify the identification of the coil to be arranged in the coil groove, the groove width and groove depth of the notch groove provided on the end face are also reduced. By making only one different from the others, the phase matching of the coil becomes easy.

〔Example〕

FIG. 1 is an assembled sectional view of an embodiment according to the present invention, and FIGS. 2 (a) and 2 (b) are plan and sectional views of a center core according to an embodiment of the present invention. FIG. 3 (a) is a cross-sectional view and a lower plan view of the outer core of one embodiment according to FIG.
FIGS. 4 (a) and 4 (b) show a cross-sectional view and a lower plan view of the inner core of one embodiment according to the present invention. This embodiment will be described.

First, a method of manufacturing the center core 2 will be described. The center core 2 is formed by compression molding a ferrite raw material to form a cylindrical core. At this time, the notch 201
Then, the slit groove 202 on the inner peripheral surface is formed by a mold. Of the notch grooves, the notch groove 202b continuous with the slit groove on the inner peripheral surface is formed to have the same width as the slit groove, and the notch groove 201a corresponding to the slit groove formed on the outer peripheral surface is , Are formed wider than the notch groove 201b, and one notch groove 201c is formed wider and deeper than the other notch grooves. After firing the cylindrical core, the outer peripheral surface of the cylindrical core is polished so as to have a predetermined roundness. Based on the outer peripheral surface, the both end surfaces and the inner peripheral surface of the cylindrical core are then polished. Grind. Next, the outer peripheral surface and the inner peripheral surface are obtained by grinding the circumferential groove 204 and the outer peripheral surface by grinding the slit groove 203.

Next, a method for manufacturing the outer core 3 will be described. The outer core 3 is also obtained by substantially the same manufacturing process as that of the center core 2. First, the ferrite material is compression molded,
Form a cylindrical core. At this time, the cutout groove 30 on the end face
1 and the slit groove 302 on the inner peripheral surface are formed in a mold.
Among these notches, one notch 301a is formed wider than the other notches. After firing this cylindrical core, the outer peripheral surface of the cylindrical core is polished so as to have a predetermined roundness, then both end surfaces of the cylindrical core are polished, and then the inner peripheral surface is polished. And then a circumferential groove on the inner surface
Obtained by grinding 303.

Next, a method for manufacturing the inner core 4 will be described. The inner core 4 is also obtained in substantially the same manufacturing process as the center core 2. First, the ferrite material is compression molded,
Form a cylindrical core. At this time, one notch groove 401 is formed on the end face by a mold. After firing this cylindrical core, the outer peripheral surface of the cylindrical core is polished so as to have a predetermined roundness, then both end surfaces of the cylindrical core are polished, and then the inner peripheral surface is polished. Then, a circumferential groove 402 is formed on the outer peripheral surface.
And then grinding the slit groove 403 on the outer peripheral surface.

In the center core 2, the outer core 3 and the inner core 4 of this embodiment, the outer peripheral surface is first polished to form a core having a predetermined roundness, and the other portions are used as the outer peripheral surface as a reference surface and a support surface. It is obtained by polishing or grinding. Therefore, the dimensional accuracy of each part of the core depends on the accuracy of the outer peripheral surface, and in the present invention, the outer peripheral surface is first formed to a predetermined accuracy,
Thereafter, the other parts are processed, so that a very high-precision core can be obtained. Further, when machining the slit groove 203 on the outer peripheral surface of the center core 2, a notch groove 201c formed wider and deeper than the other was used as a reference for judging the machining position. When machining the slit groove 403 on the outer peripheral surface of the inner core 4, only one cutout groove 401 was used as a reference for judging the machining position.

Then, the center core 2 and the outer core 3 of this embodiment
A winding or a short ring is arranged in the circumferential grooves 204, 303, 402 of the inner core 4, and the lead wire of the winding is drawn out through the slit groove. The outer core 3 and the inner core 4 are bonded to the same base 5. Then, the lead wire 8 of the winding between the outer core 3 and the inner core 4 is led out through a cutout groove 301 formed on the end face of the outer core. Further, the center core is also attached to the other base 6, and the lead wire of the winding is led out through the cutout groove 201. The center transformer 2 bonded to the base was inserted between the outer core 3 and the inner core 4 to form the rotary transformer 1.

The center core 2 and the inner core 4 are respectively adhered to the base at the end faces where the notched grooves are formed, and lead wires of the winding are led out of the notched grooves. This is easier and less expensive than forming a groove or the like in the base and leading out the lead wire. When the center core 2, the outer core 3, and the inner core 4 are respectively bonded to the base,
Notch groove formed on each end face, notch groove formed wider and deeper than others in center core, notch groove formed wider than others in outer core, only one notch formed in inner core The notched groove was used as a reference for positioning.

FIG. 5 is a half sectional view of a rotary head device using one embodiment of the present invention.

〔The invention's effect〕

According to the present invention, a small, high-precision, high-performance rotary transformer can be configured, and a multi-channel rotary transformer can be configured within a limited cylinder diameter, which is extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is an assembled sectional view of one embodiment according to the present invention, FIG.
FIGS. 3A and 3B are a plan view and a sectional view, respectively, of a center core according to an embodiment of the present invention, and FIGS.
FIG. 4 is a cross-sectional view and a lower plan view of an outer core according to an embodiment of the present invention. FIGS. 4A and 4B are cross-sectional views and a lower plan view of an inner core according to an embodiment of the present invention. FIG. 5 is a half sectional view of a rotary head device using one embodiment according to the present invention. 1 ... Rotary transformer 2 ... Center core 3 ... Outer core 4 ... Inner core 5,6 ... Base 7,8 ... Lead wire 9 ... Screw 10 ... Magnetic head 11 ... Rotating drum 12 ... Rotating cylinder 13 Rotating shaft 201, 301, 401 Notch groove 202, 203, 302, 403 Slit groove 204, 303, 402 Circular groove

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Juichi Morikawa 1410 Inada, Katsuta-shi, Ibaraki Pref. Inside the Tokai Plant of Hitachi, Ltd. (72) Inventor Yuji Kanda 1-25-1, Hyakunincho, Shinjuku-ku, Tokyo Nihon Ferrite Co., Ltd. Tokyo Sales Office (72) Inventor Hideo Takaoka Twelve places in Hiratanakamiya, Iwaki-shi, Fukushima Prefecture 50 Kawara, Fukushima Tokai Electronic Industry Co., Ltd. Iwaki Factory (56) References JP-A-1-162313 (JP, A) JP-A-1-283910 (JP, A) Jikai 61-37103 (JP, U)

Claims (10)

(57) [Claims] A first cylindrical ferrite core having a circumferential groove formed on an inner circumferential surface and an outer circumferential surface; and a first cylindrical ferrite core having a circumferential groove formed on an inner circumferential surface. A second cylindrical ferrite core is disposed outside the ferrite core with a predetermined gap therebetween, and a circumferential groove is formed on the outer peripheral surface, and a predetermined gap is formed inside the first cylindrical ferrite core. A third cylindrical ferrite core interposed therebetween, wherein a slit groove is formed in an outer peripheral surface and an inner peripheral surface of the first cylindrical ferrite core in an axial direction, and the slit groove is formed inside. A rotary groove, wherein the slit groove formed on the outer side and the slit groove formed on the outer side are formed so as not to be in a straight line in a radial direction sandwiching the thickness. A first cylindrical ferrite core having a circumferential groove formed on an inner peripheral surface and an outer peripheral surface; and a first cylindrical ferrite core having a circumferential groove formed on an inner peripheral surface. A second cylindrical ferrite core is disposed outside the ferrite core with a predetermined gap therebetween, and a circumferential groove is formed on the outer peripheral surface, and a predetermined gap is formed inside the first cylindrical ferrite core. A third cylindrical ferrite core interposed therebetween, wherein a slit groove is formed in an outer peripheral surface and an inner peripheral surface of the first cylindrical ferrite core in an axial direction, and an axis of the first cylindrical ferrite core is formed. A rotary transformer, wherein a notch groove extending in the radial direction is formed at a position overlapping the slit groove on the end face in the direction. 3. A first cylindrical ferrite core having a circumferential groove formed on an inner peripheral surface and an outer peripheral surface; and a first cylindrical ferrite core having a circumferential groove formed on an inner peripheral surface. A second cylindrical ferrite core is disposed outside the ferrite core with a predetermined gap therebetween, and a circumferential groove is formed on the outer peripheral surface, and a predetermined gap is formed inside the first cylindrical ferrite core. A third cylindrical ferrite core interposed therebetween, wherein a slit groove is formed in an outer circumferential surface of the first cylindrical ferrite core in an axial direction, and the slit groove is formed on an axial end surface of the first cylindrical ferrite core. A notch groove extending in a radial direction at a position overlapping with the notch groove, wherein a width of the slit groove is different from a width of the notch groove. 4. The rotary transformer according to claim 2, wherein one notch groove of said first cylindrical ferrite core is formed deeper than another notch groove or has a width smaller than that of another notch groove. A rotary transformer characterized in that it is also widely formed. 5. A first cylindrical ferrite core having a circumferential groove formed on an inner peripheral surface and an outer peripheral surface; and a first cylindrical ferrite core having a circumferential groove formed on an inner peripheral surface. A second cylindrical ferrite core disposed outside the ferrite core with a predetermined gap therebetween, and a circumferential groove formed on the outer peripheral surface, and a predetermined gap inside the first cylindrical ferrite core. A slit groove is formed in the inner peripheral surface of the second cylindrical ferrite core in the axial direction, and the third cylindrical ferrite core has an axial end face formed on the inner peripheral surface of the second cylindrical ferrite core. A rotary transformer, wherein a cutout groove extending in the radial direction is formed at a position overlapping the slit groove. 6. The rotary transformer according to claim 5, wherein one notch groove of said second cylindrical ferrite core is formed deeper than another notch groove, or has a width smaller than that of another notch groove. A rotary transformer characterized in that it is also widely formed. 7. The rotary transformer according to claim 5, wherein a slit groove is formed in an outer circumferential surface and an inner circumferential surface of the first cylindrical ferrite core in an axial direction, and the first cylindrical ferrite core has an axial direction. A cutout groove extending in the radial direction is formed at a position overlapping the slit groove on the end face,
A rotary transformer, characterized in that the end faces of the first cylindrical ferrite core and the second cylindrical ferrite core where the cutout grooves are formed are different from each other. 8. The rotary transformer according to claim 5, wherein said third cylindrical ferrite core and said second cylindrical ferrite core are adhered to a same base, and said second cylindrical ferrite core is provided with said notch. A rotary transformer, wherein the rotary transformer is adhered to the base on a surface where the groove is formed. 9. The rotary transformer according to claim 1, wherein slit grooves formed on an inner peripheral surface and an outer peripheral surface of the first cylindrical ferrite core are respectively spaced at equal intervals in a circumferential direction. A rotary transformer, which is arranged. 10. The rotary transformer according to claim 5, wherein slit grooves formed on an inner peripheral surface of said second cylindrical ferrite core are arranged at equal intervals in a circumferential direction. Trance.