JPH05290302A - Rotary magnetic head device - Google Patents

Abstract

PURPOSE:To simplify the structure of a secondary side rotary transformer and to facilitate assembling by drawing the plural coils of the rotary transformer along plural radial grooves provided at a core in the rotary magnetic head device of a DAT or a VTR. etc. CONSTITUTION:This device is comprised in such a way that the coils 32a and 32b locabed at four concentric circular grooves 31 of the core of the rotary transformer passing a first radial groove 33a and the coils 32c and 32d passing a second radial groove 33b are drawn to an FPC 35 fixed on a back plane. Thereby, the device can be comprised with easy assembling, and also, it is possible to perform wiring work without impairing the accuracy of a cylinder in narrow space and to reduce cost when the miniaturization of the rotary magnetic head device and the making of the device into multiple channels are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary magnetic head device for a magnetic recording / reproducing device such as a DAT, a VTR and a data memory.

[0002]

2. Description of the Related Art Generally, DAT and VTR have a rotary cylinder having a magnetic head and a fixed cylinder coaxially arranged under the rotary cylinder, and a magnetic tape is helically wound around these cylinders. .. A magnetic head mounted on the rotary cylinder scans the tape obliquely. In such a case, in order to exchange the signal of the magnetic head between the rotating side and the fixed side, the signal is generally transmitted via a rotary transformer and then amplified. At this time, the coil arranged on the secondary side rotary transformer is soldered to a printed circuit board or the like and relayed to a head amplifier by a lead wire, an FPC or the like. An example of a conventional rotary magnetic head device will be described below with reference to the drawings.

FIG. 2 shows a commonly used rotary magnetic head device. The rotary magnetic head device rotates the rotary cylinder 2 with respect to the rotary cylinder 2 to which the magnetic head 1 is attached, a fixed cylinder 3 forming a pair with the rotary cylinder 2, a bearing portion 4 fitted to the fixed cylinder 3, and the fixed cylinder 3. The shaft 5 and the disk 6 fitted to the shaft 5, the primary side rotary transformer 7 fixed to the disk 6, the primary side rotary transformer 7 and the fixed cylinder 3 are arranged to face each other with a gap therebetween. And a secondary side rotary transformer 8. The primary side rotary transformer 7 and the secondary side rotary transformer 8 are
Signals are exchanged between the fixed magnetic recording / reproducing apparatus main body and the rotating magnetic head 1.

Next, the operation will be described. During recording, a signal from the amplifier is applied to the coil arranged in the groove of the secondary side rotary transformer 8, and a magnetic flux is generated between the primary side rotary transformer 7 via the gap. This magnetic flux is 1
An induction voltage is generated in the coil arranged in the groove of the secondary rotary transformer 7, a magnetic field is generated in the magnetic head 1, and a signal is recorded on the magnetic tape. During reproduction, the signal generated in the magnetic head 1 is applied to the primary-side rotary transformer 7 made of a magnetic material, and magnetic flux is generated between the secondary-side rotary transformer 8 via the gap. Due to this magnetic flux, an induced voltage is generated in the coil arranged in the groove of the secondary side rotary transformer 8 and the signal is transmitted to the amplifier. FIG. 3 shows a first example of the conventional secondary side rotary transformer. The configuration of the rotary transformer of FIG. 3 is such that the ends of the coils 10 arranged in the plurality of grooves 14 of the core 17 of the secondary side rotary transformer are passed through the through holes 11 provided in the core 17 to the side opposite to the core coil groove. FPC attached
Foil 13 provided on (flexible printed wiring board) 12
Is soldered to. The FPC 12 is relayed to the head amplifier.

FIG. 4 shows a state in which the rotary transformer of the first example is incorporated in the fixed cylinder 3. The bearing 4 and the shaft 5 are already incorporated in the fixed cylinder 3. The outer circumference of the fixed cylinder is notched with a width d, and the FPC 12 is pulled out from the notch. FPC1
2 uses a double-sided board, and by fixing it to the fixed cylinder 3 while pressing the foil surface 15 of the FPC connected to the ground of the head amplifier with the head of the screw 16 from the side opposite to the coil solder surface of the FPC 12, The fixed cylinder is grounded.

FIG. 5 shows a second example of the conventional secondary side rotary transformer. The state where the secondary side rotary transformer is incorporated in the fixed cylinder 3 is shown. A groove 20 dedicated to pulling out the coil is provided on the groove side of the secondary side rotary transformer to pull out the ends of the plurality of coils 21, and soldering work is performed on the printed circuit board 23 stuck to the side opposite to the coil groove 22 side of the core as it is. I do. The solder surface of the printed circuit board 23 is provided on the core coil groove 22 side. The printed circuit board 23 and the head amplifier circuit are relayed by, for example, a shield wire. In addition, the head of the screw 24 makes the printed circuit board 2
The head amplifier and the fixed cylinder 3 are grounded by fixing them to the fixed cylinder 3 while pressing the foil surface of 3.

[0007]

However, in the structure of the rotary transformer as shown in FIG. 3, when the rotary transformer is assembled, a plurality of coils are wound before the coil wound with a predetermined number of turns is inserted into the groove of the core and adhered. Since the terminal had to be passed through a plurality of holes provided in the core of the rotary transformer, the work was difficult and automation was difficult. Also, when a plurality of coil terminals are pulled out from the same core hole and soldered to the FPC, they are turned over, making it difficult to distinguish the channels. Further, when the rotary magnetic head device is downsized, the thickness of the core becomes thin, and when a hole is provided in the core, the strength becomes weak, which not only causes cracking but also increases the processing cost due to the hole processing.

Further, as shown in FIG. 5, a coil drawing groove is provided on the coil groove side of the rotary transformer to draw out the coil, and the solder surface of the substrate is provided on the coil groove side of the rotary transformer to solder the coil. However, when the number of channels increases, a plurality of coils are pulled out, so that a space for soldering the plurality of coils is required. Further, in order to connect the fixed cylinder to the ground of the head amplifier circuit, the head of the screw fixes the printed circuit board foil surface while fixing it, so that a space is required so that the screw does not contact the coil. In order to secure the space, the notch on the outer periphery of the fixed cylinder must be made large, which may deteriorate the accuracy of the fixed cylinder. Providing a notch on the outer periphery of the fixed cylinder facilitates assembly of the secondary side rotary transformer, but at the time of cutting the tape guide lead provided on the outer periphery of the fixed cylinder, the boundary of the notch is Since the cutting resistance increases when the cutting tool passes and the cutting accuracy of the lead deteriorates due to the cutting tool vibrating, it is desirable to make the width of the groove as small as possible.

In view of the above-mentioned conventional problems, the present invention can cope with the multi-channel of the head and realize the cost reduction by making the coil arrangement of the secondary side rotary transformer simple. The present invention has been made for the purpose of providing the rotating magnetic head device.

[0010]

In order to solve the above-mentioned problems, a rotary magnetic head device of the present invention comprises a fixed cylinder and a rotary cylinder which is rotatable with respect to the fixed cylinder and which is equipped with a magnetic head. A plurality of coils incorporated in a secondary-side rotary transformer provided in a fixed cylinder are routed along a plurality of radial grooves provided on the core surface to a printed circuit board located on the back side of the core.

[0011]

In the rotary transformer according to the above means, when the coil is assembled in the core of the rotary transformer,
Since it is not necessary to pass the coil through the hole provided in the core as in the conventional case, the work is simplified and automation can be supported.
Further, since the radial grooves of the core can be easily formed by using a mold, there is no need to make holes in the post-processing as in the conventional case, so that the cost of the core can be reduced. By arranging a plurality of coil terminals on the back surface of the core along a plurality of grooves provided for each channel, the channels can be easily distinguished.
Moreover, even if the number of channels increases, there is no risk that the screws for grounding the fixed cylinder and the head amplifier circuit will come into contact with the coil even if the number of channels increases, and it is necessary to enlarge the cutout on the outer circumference of the fixed cylinder. Therefore, the accuracy of the fixed cylinder can be secured.

[0012]

Embodiments of the rotary magnetic head device of the present invention will be described in detail below with reference to FIG. This first embodiment is applied to a plane-opposing rotary transformer.

FIG. 1 is a schematic view of a rotary transformer of a rotary magnetic head device according to an embodiment of the present invention. In the structure of the rotary transformer, a plurality of grooves 31 are concentrically formed with a predetermined depth in a core 30 made of a magnetic material such as ferrite. A plurality of coils 32 are installed in the groove 31 with a predetermined number of turns. FIG. 1 shows a rotary transformer in the case of four heads. Basically, the number of grooves 31 and the number of coils 32 each may be four, but in consideration of the influence of crosstalk, the short ring 33 has inner and outer coils. The total number of grooves is five because it is provided between the two. The coils 32a and 32b are bonded to the back surface of the core 30 through a groove 33a which is slightly deeper than the groove 31 and which is radially provided to the core 30, and the coils 32c and 32d are through a groove 33b which is located at a predetermined angle with respect to the groove 33a. It is drawn around to the foil 36 of the FPC 35 and soldered. When incorporated in a fixed cylinder, the FPC 35 of the double-sided board is provided with a grounding foil 37, as described in the conventional example of FIG. 4, and by pressing the foil 37 with the head of the screw, the foil is inserted through the screw. It is possible to connect the fixed cylinder to the ground of the head amplifier circuit.

A method of assembling the rotary transformer will be described. The coil 32, which has been wound in a predetermined number of turns in advance, is inserted along the groove 31. At this time, the ends of the coil are pulled out along the radial grooves 33. This can be distinguished by changing the length of the winding start and the winding end of the end of the coil. The coils are sequentially inserted from the inner circumference, the coils 32a and 32b are drawn out from the groove 33a, and the coils 32c and 32d are drawn out from the groove 33b. After inserting all the coils, pressure bonding is performed. After the adhesive is cured, the core is turned over and the ends of each coil are bent along the core of the FPC and soldered to the foil provided on the FPC. Even when turned upside down, the positions where the coils are pulled out are separate, so there is no mistake when soldering.

A magnetic tape is helically wound around a fixed cylinder and a rotary cylinder having a rotary transformer having the above-described structure, and a magnetic head attached to the rotary cylinder scans the tape obliquely. Then, in order to exchange the signals of the magnetic head between the rotating side and the fixed side, the signals are transmitted via a rotary transformer, and predetermined recording / reproducing is performed. With this configuration, not only was the assembly of the rotary transformer easier, but the problem was how to handle the terminal treatment of the coil of the conventional rotary transformer within a limited range, but the number of channels increased. However, since it is not necessary to increase the notch on the outer circumference of the fixed cylinder, it is possible to perform line processing in a narrow space without deteriorating the accuracy of the fixed cylinder. Further, even if the head has multiple channels, the shortest earth can be established between the fixed cylinder and the head amplifier board, so that noise does not form a loop and the S / N of the RF transmission system is not deteriorated.

Although the present invention has been described above with reference to an embodiment shown in the drawings, the present invention is not limited to the above embodiment, and various modifications can be made based on the technical idea of the present invention. For example, the FPC may be a phenol or glass epoxy board, and the relay from the board to the head amplifier board is a shielded wire or FPC.
May be Further, the number of coils and the number of grooves may be the same or different.

[0017]

As described above, according to the present invention, as described above, in the fixed cylinder and the rotary cylinder that is rotatable with respect to the fixed cylinder and is provided with the magnetic head, the secondary cylinder provided in the fixed cylinder. A plurality of coils incorporated in the rotary transformer on the side are routed along a plurality of radial grooves provided on the core surface to a printed circuit board located on the back side of the core. Therefore, the structure of the rotary transformer is simplified, and at the same time, the assembly is facilitated, and the line processing in a narrow space due to the miniaturization of the rotary magnetic head device and the increase in the number of channels becomes possible without impairing the accuracy of the fixed cylinder. Further, since the shortest earth can be established between the fixed cylinder and the head amplifier board, the S / N of the RF transmission system is not deteriorated.

[Brief description of drawings]

1A is a top view showing an embodiment of a rotary transformer of a rotary magnetic head apparatus according to the present invention, and FIG. 1B is a side sectional view showing an embodiment of a rotary transformer of a rotary magnetic head apparatus according to the present invention. FIG. 3C is a bottom view showing an embodiment of the rotary transformer of the rotary magnetic head device of the present invention.

FIG. 2 is a vertical sectional view showing an example of a conventional rotary magnetic head device.

3A is a top view showing an example of a conventional rotary transformer, FIG. 3B is a side sectional view showing an example of a conventional rotary transformer, and FIG. 3C is a bottom view showing an example of a conventional rotary transformer.

FIG. 4A is a top view showing an example in which a conventional rotary transformer is incorporated in a lower cylinder, and FIG. 4B is a side sectional view showing an example in which a conventional rotary transformer is incorporated in a lower cylinder.

5A is a top view showing a second example of a conventional rotary transformer, and FIG. 5B is a side sectional view showing a second example of a conventional rotary transformer.

[Explanation of symbols]

 3 Fixed Cylinder 7 Primary Side Rotary Transformer 8 Secondary Side Rotary Transformer 30 Core 31 Groove 32 Coil 33a, 33b Groove 35 FPC

Claims (1)

[Claims] 1. A fixed cylinder and a rotary cylinder that is rotatable with respect to the fixed cylinder and includes a magnetic head, wherein a plurality of coils incorporated in a secondary-side rotary transformer provided in the fixed cylinder are provided. A rotary magnetic head device comprising: a plurality of radial grooves provided on a surface of a core, and a printed board located on the back side of the core.