JPH02128308A - Magnetic head - Google Patents

Abstract

PURPOSE:To eliminate the need of providing a ground, 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:A core 3 is inserted through a base part bobbin 11 and a drum part bobbin 21 and contained, end parts of its front part are allowed to abut on each other through a gap spacer 8, and also, end parts of the rear part are allowed to abut on each other, and thereafter, an assembly 31 of the core 3, the base part bobbin 11 and the drum part bobbin 21 is inserted into a case, and engaged and assembled. In such a way, it is unnecessary to provide the ground, its handling can be facilitated by decreasing the number of parts, and also, by simplifying the centering of each part, the magnetic head which is small in size and whose cost is low can be obtained.

Description

Detailed Description of the Invention (3-1) Industrial Application Field 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 the head.

(3-2) Conventional technology Magnetic heads used in audio equipment and audiovisual equipment convert audio and video into magnetic signals via electrical signals, and convert magnetic signals into audio and video via electrical signals. It has a regenerating function, and its structure is illustrated in FIG. 6 (perspective view exploded into main parts) and FIG. 7 (cross-sectional view of main parts). In other words, in both figures,
The magnetic head 1 consists of a holder 2, a core 3, a bobbin 7 around which a terminal 41 winding attached to a terminal plate 5 is wound to form a coil 6, a case (not shown), and the like. , the rear parts 3 a of the pair of cores are inserted through both open ends of the through hole 7 a of the bobbin.
a, and the end surfaces of the front surfaces 3b of both cores are brought into contact via a gap spacer (not shown), and then the terminal plate 58 and the terminal 4 are attached, and these are held in a pair of holders. It was assembled by fitting it into the case after installing it inside the 2.

In recent years, magnetic heads have become increasingly smaller.

For example, the core used in video cameras has a thickness of 150 to 500 u and a width of about 0.8 mm, and the parts mentioned above have also been miniaturized accordingly. The conventional structure has a large number of parts and is small, making it difficult to handle, and centering each part requires time and effort, resulting in an overall high cost.

(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.

(3-4) Means for Solving the Problems The present invention solves the above-mentioned problems by configuring the magnetic head as follows. That is, it consists of a front part, a middle part, and a rear part, and has a substantially U-shaped shape, and is integrally molded from a magnetic material plate, and is cylindrical and has a cylindrical inner part into which the rear part of the core is inserted. The outer side has a through hole through which the winding is wound to form a coil and a terminal pin is erected, and a base bobbin made of a non-magnetic material such as resin, ceramic, or copper alloy, and the base bobbin. The body is made of a non-magnetic material such as resin, ceramic, copper alloy, etc. and has a box-like shape. and a case formed from a metal material such as permalloy and having an engaging portion on the inner surface that engages with the sides of the base bobbin and the body bobbin, and the core is connected to the base bobbin and the body bobbin. The core, base bobbin, and body bobbin are inserted into the main bobbin, their front ends are brought into contact with each other via a gap spacer, and their rear ends are brought into contact with each other. The magnetic head is assembled by inserting and engaging the assembled product into the case.

The attachment and detachment of the base bobbin and body bobbin is easy and convenient if they have a very small tightening margin and consist of a prismatic convex portion and a concave portion that fit into each other.

The assembly of core, base bobbin, and body bobbin consists of one set (
In addition to single-channel magnetic heads consisting of 2 cores, one base bobbin, and one body bobbin, there are also multi-channel magnetic heads consisting of n sets of cores, n base bobbins, and one body bobbin. You can also make one. However, in this case, it is desirable that the body bobbin has n independent cavities.

Normally, one of the cores in each set needs to be grounded by an appropriate means, but a part that communicates with the outside is provided in the storage part of the middle part of the core in the cavity of the body bobbin, and that part is connected to the side edge of the core. protrudes outward, and when the core, base bobbin, and body bobbin assembly is inserted into the case, the side edge of one middle part of each set of cores should be in direct contact with the case, and the side edge of the other middle part should be in direct contact with the case. By bringing the cores into contact with the case through an insulating material, one of the cores in each set can be grounded.

The shape of the engaging portion of the case can be a groove or a protrusion. In addition, the materials for the base bobbin and body bobbin include resin,
There are ceramics and fR gold alloys, but resin is easier to use because of its properties.

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

FIG. 1 is a perspective view showing a base bobbin, a body bobbin, and a core of a magnetic head according to the present invention. In the figure, the core 3 has a substantially U-shape, consisting of a front portion 3b, an intermediate portion 3C, and a rear portion 3a, and is integrally formed from a magnetic material plate.

The base bobbin 11 has a cylindrical shape and is molded from a non-magnetic material such as resin, ceramic, or copper alloy, and has a coil 13 wound around the outside thereof. Further, a terminal bin 14 is erected near the end thereof. The inner side of the center portion of the base bobbin is a through hole 11a, and grooves 1.1b communicating with the through hole are provided at both ends. Further, one surface of the center portion of the base bobbin is a prismatic recess 11c.

The body bobbin 21 has a substantially rectangular parallelepiped shape, and is molded from a non-magnetic material such as resin, ceramic, copper alloy, etc., like the base bobbin. A substantially treat-shaped cavity 22 is provided inside thereof. Openings 22a and S''2b communicating with the cavity 22 are provided on two opposing surfaces of the body bobbin 21.The base bobbin 11 is provided on the − side of the body bobbin 21.
A prismatic protrusion 21a is provided which fits into the recess 11c with an extremely small interference margin.

Move the two cores 3 in the direction of arrow X in the figure, insert their rear parts 3a into the through holes 11a of the base bobbin, and bring the ends of the front parts 3b of both cores into contact with each other through the gap spacer 8. After the ends of the rear parts 3a are brought into contact with each other, the front part 3b and middle part 3d of the two cores 3 are inserted into the opening 22b of the body bobbin 22 or the gap 22, and the front part 3b of the core is inserted from the opening 22a. protrudes outward, and the recess 1 of the base bobbin
1c and the convex portion 21a of the body bobbin, an assembly 31 of the core, base bobbin, and body bobbin is assembled. This assembly 31 is shown in FIG. 3(a).

FIG. 2 shows another example of the body bobbin 21.

That is, in this example in the figure, in addition to openings 22a and 22b, an opening 22c is provided on another opposing surface of the body bobbin 21.

In this example, the side edge 3d (first
(see figure) is assembled in such a state that it protrudes outward from this opening 22c. The assembly 31 of the core, base bobbin, and body bobbin in this example is as shown in FIG. 3(b).

4(a) and 4(b) are perspective views showing the case 32. FIG. In the figure, a case 32 has a box-like shape and is made of a metal material such as permalloy. An opening 32a 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 (a) is a protrusion 32b, and the engaging portion shown in (b) is a groove 32c. The assembly 31 of the core, base bobbin, and body bobbin described above is inserted into this case so that the front surface 3b of the core comes out from the opening 32a. The side ridges of the bobbins engage with the protrusion 32 (in the case of (a) figure), or the side parts of both bobbins engage with the grooves 32c (in the case of (b) figure). The bobbin and body bobbin assembly 31 can be centered. Also in this case, the third
In the case shown in FIG. If the core is not connected to the ground, the one core can be completely grounded. In this case, if the inner dimension of the case 32 is precisely machined, an appropriate pressing force can be applied to both ends of the core 3, which can be useful for improving the performance of the magnetic head.

In the case shown in FIG. 3(a), it is not possible to ground by the method shown in the above-mentioned (opening) diagram, so it is necessary to use another method (not shown).

FIG. 5 shows an example in which the present invention is applied to a multi-channel magnetic head, and an assembly 31 of the core, base bobbin, and body bobbin is shown. In this example, the body bobbin 21 is provided with a plurality of (two in the figure) independent gaps 22, and the plurality of base bobbins 1
1 is attached by fitting the convex portion 21a and the concave portion 11c. Further, as shown in the figure, a plurality of cores 3 protrude from the opening of the body bobbin. This assembly 31
is inserted into the case 32 as described above to assemble a multi-channel magnetic head. Assembly 31 and case 3
The method of engagement with 2 is also the same as in the embodiments described above. This example has the advantage of allowing extremely accurate centering between the channels of a multi-channel magnetic head.

(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 required.

■ It is possible to eliminate the need to provide a special ground.

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

■ Centering is accurate. In particular, centering between each channel of a multi-channel magnetic head can be performed extremely accurately.

■ Cost can be reduced due to fewer steps 6

[Brief explanation of drawings]

FIG. 1 is a perspective view showing a base bobbin, a body bobbin, and a core of a magnetic head according to the present invention, FIG. 2 is a diagram showing another example of a body bobbin 21, and FIG. 3 (A) , (B) is a diagram showing the assembly of the core, base bobbin, and body bobbin, FIG. 4 (A) and (B) are perspective views showing the case, and FIG. A perspective view showing an example of application to a magnetic head, FIG. 6 (perspective view exploded into main parts), and FIG. 7 (sectional view of main parts) are diagrams illustrating conventional magnetic heads. ■...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 8...Gap spacer 11...Base bobbin lla...Through hole 11b...Groove
lie... recess 12... volume II l
3... Coil 14... Terminal bin 21... Body bobbin 21a... Convex portion 22... Gaps 22a, 22b, 22c... Opening 31... Core, base bobbin, body bobbin Assembled product 32...Case 32a...Opening 32b--Protrusion 32cm/Groo Patent applicant TDC Co., Ltd. agent
Patent Attorney Tsukamoto Daisan Department 2'2b 21a Figure 5

Claims (6)

[Claims] (1) A core consisting of a front part, a middle part, and a rear part, having a roughly J-shaped shape, and integrally molded from a magnetic material plate, and a cylindrical core with an inner side that covers the rear part of the core. It is a through hole for insertion, and the outer side has a coil wound around it, and terminal pins are provided upright. It is attached to the base bobbin, has a cavity inside which accommodates the middle part and part of the front part of the core, and has a body bobbin made of non-magnetic material such as resin, ceramic, copper alloy, etc., and a box-shaped body bobbin. The case is formed from a metal material such as permalloy, and has an engaging portion on its inner surface that engages with the sides of the base bobbin and the body bobbin, and the core is connected to the base bobbin. The core, the base bobbin, and the body bobbin are inserted into and stored in the body bobbin, and their front ends are brought into contact with each other via a gap spacer, and their rear ends are brought into contact with each other. A magnetic head characterized in that it is assembled by inserting and engaging the assembly into the case. (2) The magnetic head according to claim 1, wherein the mounting portion between the base bobbin and the body bobbin is comprised of a prismatic convex portion and a concave portion that fit into each other. (3) The assembly of the core, base bobbin, and body bobbin consists of one set (two cores) and one base bobbin and one body bobbin, respectively. The magnetic head according to item 1. (4) The assembly of the core, base bobbin, and body bobbin includes n sets (multiple sets) of cores, one body bobbin having n independent voids, and n base bobbins. A magnetic head according to claim 1 or 2, characterized in that the magnetic head comprises: (5) The storage part of the middle part of the core in the gap of the body bobbin communicates with the outside, and when the assembly of the core, base bobbin, and body bobbin is inserted, one of the cores in each set is inserted. Claims 1 to 4, characterized in that a side edge of the intermediate portion of the intermediate portion is in direct contact with the case, and a side edge of the other intermediate portion is in contact with the case via an insulating material. A magnetic head according to any one of the above. (6) The engaging portion of the case is a protrusion or groove that engages with the side portions of the base bobbin and body bobbin. The magnetic head described in .