JPH02128307A - Magnetic head - Google Patents

Abstract

PURPOSE:To facilitate the handling by decreasing the number of parts and to reduce the cost by decreasing the number of processes by constituting the magnetic head by fitting and installing directly an assembly of a core formed by installing a core in a bobbin with a coil and the bobbin with a core into a case and assembling them. CONSTITUTION:Two pieces of cores are engaged into a through-hole 7e and a groove 7d of a bobbin 8 with a coil, end parts of the front part are allowed to abut on each other through a gap spacer 10, and also, end parts of the rear part are allowed to abut on each other and assembled, and thereafter, an assembly of the core 3 and the bobbin 8 with a coil is engaged into a case and assembled. In such a way, by decreasing the number of parts, its handling can be facilitated, and also, by simplifying the centering of each part, and magnetic head which is small in size and whose cost is low can be obtained.

Description

Detailed Description of the Invention (3-11 Industrial Field of Application) The present invention relates to a magnetic head used in audio equipment, audio-visual equipment, etc., and particularly relates to an extremely miniaturized magnetic head for use in 8mm video cameras. Regarding.

(3-21 Conventional technology Audio equipment and audio video (t1) The magnetic head used in equipment converts audio and video into magnetic signals via electrical signals,
It also has the function of reproducing magnetic signals into audio and video via electrical signals, and an example of its structure is shown in Figure 5 (
It is as shown in FIG. 6 (a perspective view exploded into main parts) and FIG. 6 (a sectional view of the main parts). In other words, in both figures, the magnetic head l consists of the holder 2, the core 3, the terminal 4 attached and attached to the terminal plate 5, and the coil 6 with the winding wound around it.
The rear part 3a of the pair of cores is inserted through both open ends of the through hole 7a of the bobbin. Only one of the cores is shown in FIG. ), the end surfaces of the rear parts 3a of both cores are brought into contact with each other, and the front parts 3b of both cores are brought into contact with each other.
The end faces of the terminals are brought into contact with each other through a gap spacer (not shown), and the terminal plate 5 and the terminal 4 are attached, and after these are installed in a pair of holders 2, they are fitted into the case and assembled. It was getting worse.

In recent years, magnetic heads have become smaller and smaller.6 For example, the core thickness of those used in video cameras is 150 mm.
~500μ, and its width is about 0.8mm, and the above-mentioned parts are also miniaturized accordingly, but the conventional structure described above has a large number of parts and is small. It is difficult to handle, requires time and effort to center each part, and has the drawback of high cost overall.

(3-3) Problems to be Solved by the Invention The present invention eliminates the above-mentioned drawbacks of conventional magnetic heads, reduces the number of parts, facilitates handling, and simplifies centering of each part. The present invention aims to provide a magnetic head that is small and inexpensive.

Means for Solving the f3-41 Problems The present invention solves one or more of the problems mentioned above by configuring a magnetic head as follows. That is, it consists of a front part, a middle part, and a rear part, and has an approximately U-shaped shape, and is composed of a core integrally molded from a magnetic material plate, a base part, and two legs, and has an approximately U-shaped shape. It has a character-like shape and is made of resin,
It is integrally molded from a non-magnetic material such as ceramic or copper alloy, and the leg portion has a groove that engages with the middle portion of the core, and the base portion has a groove that engages with the rear portion of the core. It has a hole, a coil is formed by winding a winding wire on the outside of the base, and a bobbin with a coil with terminal bins standing up near both ends of the base, and a box-shaped bobbin. and a case molded from a metal material such as permalloy, and having an engaging part on its inner surface that engages with the leg part of the coiled bobbin, and the two cores are connected to the coiled bobbin through the threads of the coiled bobbin. After assembling the bobbin with the core and coil by engaging the holes and grooves, bringing the ends of the front part into contact with each other through a gap or a pacer, and bringing the ends of the rear part into contact with each other, the bobbin with the core and coil is assembled. The magnetic head is assembled by engaging the assembly in the case.

Although it is possible to assemble one assembly of a core and a bobbin with coils by engaging them in this case, a multi-channel magnetic head can be obtained by engaging a plurality of them.

One of the two cores engaged with the coil bobbin described above is usually grounded by an appropriate means, but when the assembly of the core and coiled bobbin is engaged in the case, one of the cores is grounded in the case. If the two cores are in direct contact and the other core is in contact through an insulating material, earthing can be achieved.

The engaging part of the case is precisely machined to determine its internal dimensions, and the front ends of the two cores are brought into contact with each other via a gap spacer, and the rear ends are brought into contact with each other. If the width is extremely slightly smaller than the width when the core is in contact with the thickness of the insulating material, an appropriate pressing force can be applied to the end of the core, which is useful for improving the performance of the magnetic head.
If two cores are biased by a plate-shaped metal spring so that their ends are pressed against each other, the performance of the magnetic head can be improved in the same way as described above, but in this case, one core and the spring are directly connected to each other. If they are brought into contact with each other and an insulating material is sandwiched between the other core and the spring, one core can be grounded in the same manner as described above.

The shape of the engaging portion of the case can be a groove or a protrusion. The bobbin material of the coiled bobbin includes resin,
There are ceramics, copper alloys, etc., but resins are easier to use because they have the same properties.

(3-51 Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a perspective view showing an example of a coiled bobbin and a core of a magnetic head according to the present invention. In the figure, the bobbin 7 of the coiled bobbin 8 has a base 7b and two legs 7C.
It has a substantially U-shaped shape and is integrally molded from resin, ceramic, copper alloy, etc. A coil 6 is formed by winding a wire around the outside of the base 7b. Further, a terminal bin 9 is erected at the base, and the end of the winding wire is tied to the terminal bin. A groove 7d is provided in the leg 7c of the bobbin, and a groove 7d is provided in the base 7b of the bobbin.
A through hole 7e communicating with the groove 7d is provided in the groove 7d.

The core 3 includes a front portion 3b, an intermediate portion 3C, and a rear portion 3a, has a substantially U-shape, and is integrally formed from a magnetic material plate. The two cores and the bobbin are arranged so that the cores 3 face each other as shown in the figure, are moved in the direction of the arrow The ends of the front parts 3b of both furs are brought into contact with each other via a gap spacer 10, and the ends of the rear parts 3a of both furs are brought into contact with each other.

Figures 2 and 3 are perspective views illustrating the case6.
In both figures, the case 11 has a box-like shape and is made of a metal material such as permalloy. An opening 11a is provided on the - side, and this side serves as a tape running surface. Opposed 1 perpendicular to this tape running surface
An engaging portion is provided inside the pair of side surfaces. The engaging portion shown in FIG. 2 is a protrusion 11b, and the engaging portion shown in FIG. 3 is a groove 11c. The above-described bobbin assembly with fur and coil is inserted into this case so that the front part 3b of the core comes out from the opening 11a, but at this time, the legs 7 of the bobbin
The ridge of c engages with the protrusion 11b (in the case of FIG. 2),
Or, by engaging the legs of the bobbin with the caps 11c (in the case of FIG. 3), the assembly of the core and coiled bobbin can be centered with respect to the case. In this case, the outer edge 3d (see Figure 1) of the intermediate portion 3C of one core is brought into direct contact with the case, and an appropriate insulating material (not shown) is placed between the outer edge 3d of the other fur and the case. If the core is not connected to the ground, the one core can be completely grounded.

As described above, if the inner dimension of the case is precisely machined, an appropriate pressing force can be applied to the end of the core, which is useful for improving the performance of the magnetic head.

FIG. 4(a) is a front view showing an assembled product of a core and a bobbin with a coil in another embodiment of the present invention, FIG. 4(b) is a front view of the main parts with the spring removed, and FIG. ) is a perspective view showing a spring. In this example, a notch 7f is provided in the bobbin 7 of the coiled bobbin, and after inserting the core into the coiled bobbin as in the above example, the plate-shaped metal spring 12 is inserted into the coiled bobbin.
is attached to the notch portion, and the end of each core is pressed with an appropriate force. In this case, the outer edge 3d of one core (see figure (b)) is brought into direct contact with the spring, and an appropriate insulating material (not shown) is placed between the outer edge 3d of the other core and the spring. If it is interposed, the one core can be completely grounded, as in the embodiment described above.

Furthermore, the case in which the core and coiled bobbin assembly is installed in this example is exactly the same as that shown in FIGS. 2 and 3, and the method of engagement is also the same as in the previous embodiment. .

(3-61 Effects of the Invention The present invention has the structure of a magnetic head such that the core is attached to a bobbin with a coil and the assembly of the bobbin with a coil is directly fitted into a case and assembled. It shows excellent effects as shown below.

■ No holder is required; a cored bobbin with a terminal is sufficient.

■ There is no need to provide any particular grounding.

■ Therefore, fewer parts are required and handling is easy.

■ Centering is accurate.

■ There are fewer steps and costs can be reduced.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a perspective view showing an example of a coiled bobbin and core of a magnetic head according to the present invention, FIGS. 2 and 3 are perspective views showing an example of a case, and FIG. 4 is a perspective view showing an example of a core. (A) is a front view showing an assembly of a core and a bobbin with a coil in another embodiment of the present invention, (B) is a front view of the main parts with the spring removed, and (C) is Perspective view showing the spring, Figure 5 (perspective view exploded into main parts) and Figure 6
The figure (a sectional view of a main part) is a diagram illustrating a conventional magnetic head. l... Magnetic head 2... Holder 3... Core 3a... Rear part 3b... Front part 3C... Middle part 3d... Outer edge 4... Terminal 5... Terminal board 6... Coil 7...Bobbin 7a...Through hole 7b...
- Base 7c... Leg 7d... Groove 7e... Through hole 7f... Notch 8... Bobbin with coil 9... Terminal pin 10... Gap spacer 11... Case lla... Opening 11b・Protrusion 11c ・Groove 12 ・Spring patent applicant TDC Co., Ltd. agent
Patent attorney Daisanbu Tsukamoto (Hashi)

Claims (7)

[Claims] (1) It consists of a front part, a middle part, and a rear part, and has a roughly J-shaped shape, and is made up of a core integrally molded from a magnetic material plate, a base part, and two legs, and has a roughly J-shaped shape. It has a U-shaped shape and is integrally molded from a non-magnetic material such as resin, ceramic, copper alloy, etc., and the leg portion has a groove that engages with the intermediate portion of the core. has a through hole that engages with the rear part of the core, a coil is formed by winding a winding wire on the outside of the base, and terminal pins are erected near both ends of the base. It consists of a bobbin, and a box-shaped case made of a metal material such as permalloy and having an engaging part on its inner surface that engages with the leg part of the coiled bobbin, Two cores were engaged with the through holes and grooves of the coiled bobbin, and the front ends were brought into contact with each other via a gap spacer, and the rear ends were brought into contact with each other to assemble. A magnetic head characterized in that the core and the bobbin with coil are assembled by engaging the core and the bobbin in the case. (2) The magnetic head according to claim 1, wherein the case is assembled by engaging one assembly of the core and the bobbin with a coil. (3) The magnetic head according to claim 1, wherein the case is assembled by engaging a plurality of assemblies of the core and the bobbin with coils. (4) One of the two cores is in direct contact with the case, and the other is in contact with the case via an insulating material. The magnetic head according to any one of items 3 to 3. (5) The two cores engaged with the coil bobbin have their front ends pressed against each other via a gap spacer and their rear ends pressed against each other by a plate-shaped metal spring. The magnetic head according to any one of claims 1 to 3, characterized in that the magnetic head is biased so as to come into pressure contact with each other. (6) One of the two cores is in direct contact with the metal spring, the other is in contact with the metal spring via an insulating material, and the metal spring is directly in contact with the metal spring. 6. The magnetic head according to claim 5, wherein the magnetic head is in contact with a case. (7) The magnetic head according to any one of claims 1 to 6, wherein the engaging part of the case is a groove or a protrusion that engages with the leg part of the coil bobbin. .