JPS5919456B2 - Rotating transformer device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary transformer device for contactless transmission of electrical signals from a rotating side to a stationary side, or conversely from a stationary side to a rotating side. It is effective for transmitting and receiving electrical signals from a magnetic head or to a rotating magnetic head.

Conventional rotary transformer devices used for transmitting signals to the rotating magnetic head of video tape recorders, for example, use a ferrite-based magnetic material as the opposing magnetic cores, and due to the characteristics of that material, Since then, the rotating and stationary magnetic cores have usually been attached to the rotor and stator using adhesives, respectively.

However, mounting with adhesive has various problems such as the work is complicated, replacement is almost impossible, and the accuracy of surface runout between opposing surfaces on the rotating side and the stationary side tends to vary.

The present invention cleverly employs a fixing structure using screws to solve the above-mentioned problems of the conventional example.

Hereinafter, the present invention will be explained with reference to the drawings, using an example in which the present invention is used for transmitting signals to a rotating magnetic head of a video tape recorder. FIG. 1 is a side sectional view of a two-turn magnetic head cylinder incorporating the present invention.

In the figure, 1 and 2 are a rotating cylinder and a fixed cylinder arranged above and below to constitute a rotating magnetic head cylinder 1, and the rotating cylinder 1 is rotatable by a ball bearing 3 at the center inside the fixed cylinder 2. It is attached to a rotating shaft 4 supported by a screw 6 via a rotating body 5 having a flange 5a and a boss 5b. 7a and 7b are first and second rotating magnetic heads 810 fixed to the lower surface of the rotary cylinder 1 via bases 8a and 8b, respectively, with screws 9a and 9b.
and 11 are a rotating side ferrite core and a stationary side ferrite core that constitute the rotating transformer device according to the present invention.

The rotating side ferrite core 10 is assembled by a screw 12, an elastic member 13 and a flat washer 14 (see FIG. 5).
It is attached to the lower surface of the flange portion 5a of the rotating body 5, which is a rotor. As shown in FIGS. 2 to 4, this rotating side ferrite core 10 has the rotating body 5 at its center.
a center hole 15 into which the boss portion 5b fits;
A concave notch for screw insertion (or a circular or circular through hole is also possible) formed at opposing locations on the inner wall of the
6a and 16b, first and second ring-shaped grooves 17a, 17b concentrically formed on one side, and the same surface as the first and second ring-shaped grooves 17a, 17b are formed. First and second grooves 1 formed in the diametrical direction
8a, 18b and their first and second grooves 18a
, 18b and the circular hole 15, and the first
And inside the second ring-shaped grooves 17a, 17b there is a first groove.
And second coils 20a, 20b are installed in a buried state. Here, four thin conductive wires are placed in each ring-shaped groove.
It is formed by winding one turn at a time. Both ends 21a, 21b of the first coil 20a and the second coil 20b
Both ends 22a and 22b of the first and second
The synthetic resin tube 23 is led out from the notches 19a, 19b through the grooves 18a, 18b to the opposite surface.
a, 23b.

It goes without saying that both ends 21a, 21b and 22a, 22b of the first and second coils 20a, 20b are electrically connected to the first and second rotating magnetic heads 7A, 7b, respectively. do not have.

Further, the first and second grooves 18a and 18b are
As illustrated in the figure, the notches 1.6a and 16b are provided apart from each other so as not to overlap with each other. As is clear from FIGS. 1 and 5, since the fixing screws 12 are inserted through the notches 16a and 16b, the screws 12 are used to connect the first and second coils 20a and 20b. This is to prevent the conductor from being cut or damaged. On the other hand, the fixed side ferrite core 11 has a screw 24 and an elastic member 2.
5 and a flat washer 26 (see FIG. 9), this fixed side ferrite core 11 is attached to the bottom of the fixed cylinder 2, which is the stator, as shown in FIGS. 6 and 7. , a central hole 27, concave notches (or circular or circular through holes are also acceptable) 28a, 28b, and 28c formed on the outer periphery for screw insertion, and a circular hole formed on one side in a circular manner. third and fourth ring-shaped grooves 29a, 29b, and third and fourth grooves formed in the radial direction on the same surface as the third and fourth ring-shaped grooves 29a, 29b. 30a, 30b, and a disc-shaped one having a notch 40 formed by cutting a part of the peripheral edge located between the third and fourth grooves 30a, 30b into a substantially fan shape. And the third
There is a third groove inside the fourth ring-shaped grooves 29a and 29b.
And fourth coils 31a, 31b are installed in a buried state.

Here, seven thin conductive wires are placed in each ring-shaped groove 29a, 29b.
It is formed by winding one turn at a time. Both ends 32a, 32b of the third coil 31a and the fourth coil 31b
Both ends 33a and 33b of the third and fourth
A substantially fan-shaped terminal plate 34 is guided through the concave grooves 30a and 30b to near their outer peripheral ends and is bonded to the notch 40 with an adhesive as shown by the chain line in FIG.
(See Fig. 8) A semicircular cutout 35a,
35b, and are connected by soldering to lands 36a, 36b, 37a, and 37b formed on the terminal board 34 by printed wiring technology, respectively. Note that the holes 38a, 38b, 39 formed in the terminal plate 34 shown in FIG.
Although not shown, a and 39b are designed to be inserted into and soldered to the pins of the external circuit connection terminal provided on the fixed cylinder 2, respectively.
That is, the holes 38a and 38b of the pin of the terminal
, 39a, 39b.
0 is formed. The elastic members 13 and 25 used to fix the rotating ferrite core 10 and the stationary ferrite core 11 may be made of resin, rubber, or metal spring members.

In short, by tightening the screws 12 and 24, the ferrite core 1
Any material may be used as long as it does not cause cracks or cracks in 0 and 11 and does not cause loosening of the fastening. In this example, the tightening torque is approximately 3 kg・? is managed. As illustrated in FIG. 5, the elastic member 13 has a partially cutout shape, and as illustrated in FIG. 9, the elastic member 25 has a ring shape without a cutout. The shape can be chosen arbitrarily.

In order not to reduce the transmission efficiency of the rotating magnetic head signal, the screws 12 and 24, the elastic members 13 and 25, and the flat washer 14, which are used to attach the rotating ferrite core 10 and the fixed ferrite core 11, are 26 is preferably made of a non-magnetic material.

Furthermore, the first ring-shaped groove 17a formed in the rotating side ferrite core 10 and the third ring-shaped groove 29a formed in the stationary side ferrite core 11 are made to have the same or almost the same radius, and similarly rotate. The second ring-shaped groove 17b formed in the side ferrite core 10 and the fourth ring-shaped groove 29b formed in the stationary side ferrite core 11 have the same or approximately the same radius.

Therefore, as shown in FIG. 1, both ferrite cores 10,
11 are arranged facing each other with a small gap in the vertical direction,
The first ring-shaped groove 17a and the third ring-shaped groove 29a
1, the second ring-shaped groove 17b, and the fourth ring-shaped groove 29b are opposed to each other. Therefore, the first coil 20a and the third coil 31a1 and the second coil 20b and the fourth coil 31b also face each other. Furthermore, when the rotating side ferrite core 10 and the stationary side ferrite core 11 are attached to the rotating body 5 and the stationary cylinder 2 as described above, the head of the screw 12 used for attaching the rotating side ferrite core 10 or the elastic The member 13 or the flat washer 14 is connected to the center hole 2 of the fixed side ferrite core 11.
The head of the screw 24 used to attach the fixed ferrite core 11, the elastic member 25, or the flat surface thereof is located inside the fixed ferrite core 11 in a non-contact state. The sizes and shapes of the rotating and stationary ferrite cores 10 and 11 are set so that the washer 26 is located outside the rotating ferrite core 10 without contacting it. In this embodiment, as is clear from FIG. 1, the diameter of the center hole 15 of the rotating ferrite core 10 is D1, the outer diameter of the rotating ferrite core 10 is D2, and the fixed ferrite core 11 is
When the diameter of the center hole 27 is D3 and the outer diameter of the fixed side ferrite core 11 is D4, D1<D3<<D4
The relationship is set as follows. Of course, the terminal plate 34 is also located outside the rotating ferrite core 10 so as not to be in contact with it. Note that the characteristics as a rotary transformer are almost determined by the facing area between the outer circumference of the rotating side ferrite core 10 and the inner circumference of the stationary side ferrite core 11. Since the inner and outer diameters of the side ferrite cores are different, the ring-shaped grooves 17a, 17b, 2 are formed in consideration of a slight peripheral effect.
It is necessary to determine the positions of 9a and 29b. In addition, screw the ferrite cores 10 and 11 on the rotating side and the stationary side with the screws 12.
, 24, in order to prevent the heads of the screws 12, 24 from coming into contact with the ferrite cores 11, 10 and interfering with the rotation of the rotating cylinder 1, the screws of each ferrite core 10, 11 are It is also possible to provide a counterbore with a thickness higher than the height of the screw head in the fastening part, but this is because the ferrite core is distorted when the thickness is uneven during compression molding and firing. It is undesirable because it tends to cause cracks and cracks when tightening with screws. In addition, it is preferable to have a polished surface for tightening the screws in order to prevent cracks from forming. Therefore, as in this embodiment, the surface to which the screws are tightened and the coil insertion surface are flush with each other. It is very effective to do so. Of course, in the present invention, 10 can be used as a stationary side and 11 can be used as a rotating side, and it goes without saying that the ring-shaped groove and the number of coils applied therein can be arbitrarily set. do not have. As is clear from the above description, in the rotating transformer device of the present invention, the rotating side ferrite core and the stationary side ferrite core are attached to the rotor part and the stator part with screws, respectively.
Compared to the case of using adhesive as in the conventional example mentioned above, assembly work is easier and replacement is easier, and it also improves the surface runout accuracy of the facing surfaces of the ferrite core on the rotating side and the fixed side. 〇Furthermore, since screws are tightened through an elastic member, screws are tightened from the coil insertion side, and the thickness of the ferrite core can be made uniform, there is no possibility of cracking when tightening screws to the ferrite core. , it is possible to realize a rotating transformer device that is less prone to cracks and is highly reliable. Furthermore, by attaching a terminal plate for coil wire processing to the fixed ferrite core, it has many features such as easy connection to an external circuit.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a two-rotation magnetic head cylinder for a video tape recorder to which the present invention is applied; FIG. 2 is a bottom view of the rotating ferrite core portion in an embodiment of the present invention;
FIG. 3 is a right side view thereof, FIG. 4 is a sectional view taken along the line A-A in FIG. 7 is a sectional view taken along line B-B in FIG. 6, FIG. 8 is a top view of the terminal plate used in the same example, and FIG. 9 is a top view of the terminal plate used in the same example. FIG. 3 is an exploded perspective view of essential parts for explaining the mounting structure of the fixed side ferrite core. 1...Rotating cylinder, 2...Fixed cylinder, 4...Rotating shaft, 5...Rotating body, 10...Rotating side ferrite Core, 11...
...Fixed side ferrite core, 12, 24...
・Screw, 13, 25...Elastic member, 15, 27
・・・・・・Center hole, 16a, 16b, 28a, 28b
, 28c... Notch, 17a, 17b, 29a
, 29b...Ring-shaped groove, 18a, 18b, 3
0a, 30b... Concave groove, 20a, 20b, 31
a, 31b... Coil, 34... Terminal plate, 36a, 36b, 37a, 37b... Land, 40... Notch.

Claims (1)

[Scope of Claims] 1. A first ferrite core and a second ferrite core each having a flat plate shape, each having a required number of ring-shaped grooves formed in one main plane, and a coil provided in the ring-shaped grooves. The first and second ferrite cores are arranged so that the respective ring-shaped grooves or the respective coils face each other with a required gap, and one ferrite core is provided in the rotor portion and the other ferrite core is provided in the rotor portion. A rotary transformer device configured to attach a core to a stator part,
The first and second ferrite cores are each provided with a notch or hole for inserting a fixing screw, and the fixing screw is inserted into the notch or hole to attach the first and second ferrite core to the rotor part. and the first stator.
and a second ferrite core, the diameter of the center hole of the first ferrite core is D_1, the outer diameter of the first ferrite core is D_2, the diameter of the center hole of the second ferrite core is D_3, and the diameter of the center hole of the first ferrite core is D_3. The outer diameter of the ferrite core of No. 2 is D
_4, the relationship D_1<D_3<D_2<D_4 is set, and the head of the fixing screw involved in attaching the first ferrite core is placed in the center hole of the second ferrite core. is located in a non-contact state, and the head of a fixing screw involved in attaching the second ferrite core is located outside the first ferrite core in a non-contact state. A rotating transformer device characterized by: 2. The rotary transformer device according to claim 1, wherein the fixing screw has an elastic member between its head and the tightening surface of the ferrite core.