GB2183199A - Magnetic head encapsulating processes - Google Patents
Magnetic head encapsulating processes Download PDFInfo
- Publication number
- GB2183199A GB2183199A GB08624945A GB8624945A GB2183199A GB 2183199 A GB2183199 A GB 2183199A GB 08624945 A GB08624945 A GB 08624945A GB 8624945 A GB8624945 A GB 8624945A GB 2183199 A GB2183199 A GB 2183199A
- Authority
- GB
- United Kingdom
- Prior art keywords
- terminal
- bobbin
- magnetic head
- land
- holding portion
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 17
- 239000011347 resin Substances 0.000 claims abstract description 20
- 229920005989 resin Polymers 0.000 claims abstract description 20
- 238000004804 winding Methods 0.000 claims description 4
- 238000000465 moulding Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 2
- 229930182556 Polyacetal Natural products 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- 229920006324 polyoxymethylene Polymers 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C45/00—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor
- B29C45/14—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles
- B29C45/14639—Injection moulding, i.e. forcing the required volume of moulding material through a nozzle into a closed mould; Apparatus therefor incorporating preformed parts or layers, e.g. injection moulding around inserts or for coating articles for obtaining an insulating effect, e.g. for electrical components
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
- G11B5/127—Structure or manufacture of heads, e.g. inductive
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/005—Impregnating or encapsulating
Landscapes
- Engineering & Computer Science (AREA)
- Manufacturing & Machinery (AREA)
- Power Engineering (AREA)
- Mechanical Engineering (AREA)
- Magnetic Heads (AREA)
- Electrolytic Production Of Metals (AREA)
Abstract
A magnetic head fabricating process includes the steps of: forming a bobbin (24) having a terminal holding portion (25) with the bobbin supporting a coil (27) and the portion (25) holding a terminal (28); mounting the bobbin (24) in a magnetic core; and encapsulating the bobbin (24) and the magnetic core (23) in an injected resin (33). Before the encapsulating step, the magnetic core (23) is inserted into a mould or form (31, 32) having a terminal hole provided with a land (30) extending around the terminal hole, and the terminal holding portion (25) is brought into abutment with the land (30) to close the terminal hole, and seal the terminal (28) against ingress of injected resin, which would otherwise encapsulate it and require removal causing damage to the terminal. The bobbin (24) is preferably made of relatively soft resin, to enhance the seal with the land (30). <IMAGE>
Description
SPECIFICATION
Processes for fabricating magnetic heads
The present invention relates to processes for fabricating magnetic heads. Magnetic heads and in particular magnetic erasing heads are used in recorders or VTRs.
It is an object of the present invention to provide an improved process for fabricating a magnetic head.
According to the present invention, there is provided a magnetic head fabricating process comprising the steps of: forming a bobbin with a terminal holding portion having a terminal and a coil winding portion; mounting said bobbin in a magnetic core; and moulding said bobbin and said magnetic core, wherein the improvement comprises the steps of: inserting said magnetic core into a mould having a terminal hole and a land around said terminal hole; bringing said terminal holding portion into abutment against said land to clog said terminal hole; and subsequently conducting said moulding step.
In the operation of the above-specified technical means, in case the magnetic head is to be moulded of a resin, the magnetic core is inserted into the mould having the land surrounding the terminal hole, and the terminal holding portion is brought into abutment against the land so that no resin will intrude into the terminal hole.
A magnetic head fabrication process embodying tye present invention will now be described, by way of example, with reference to the accompanying diagrammatic drawings, in which:
Figure 1 is a section through a magnetic head made by a process embodying the present invention;
Figures 2 and 3 are enlarged explanatory views showing a portion of the head of Fig. 1 and another head both made by a process embodying the present invention; and
Figure 4 is a section through a former and the process for fabricating the magnetic head according to the prior art example.
A previously proposed magnetic head is illustrated in Fig. 4. As shown the head includes a bobbin 6, a coil 4 wound around the bobbin and having a plated terminal 5 mounted on a magnetic core 3 formed by a front core 1 and a U-shaped back core 2, to provide a head body 7.
The head body 7 thus constructed is inserted into a bottom form or mould 9 which is formed into a rectangular shape and with a terminal slot 8 in its lower side. The terminal slot 8 is slightly larger than the terminal 5.
After a top form 10 has been placed on the bottom form 9 to partially encase the head body 7, a resin 10 is injected to partially encapsulate the head body 7 and so complete the formation of the magnetic head. In the magnetic head thus formed, the resin 10 will have intruded into the gap between the terminal 5 and the terminal slot 8, while the head is bein formed, so that it covers the terminal 5. The resin 10 covering the terminal 5 needs to be removed by means of a jig, and the magnetic head is completed by polishing its tape running face.
With this fabrication process therefore the resin 10 tends to enter the terminal slot 8 of the mould to bury the terminal 5, and the terminal 5 is also liable to be deformed, when it is deburred. As a result its plated layer is removed and so its solderability.
The magnetic head shown in Fig. 1 includes a magnetic head body 10 having a magnetic core 23 composed of a front core 21 and a back core 22, and bobbin 24. The front core 21 is formed with a groove (although not shown) which has the function of a gap. The bobbin 24 is composed of a rectangularshaped terminal holding portion 25 and a coil winding portion 26 formed with a hole (although not shown) into which the back core 22 is inserted, and is integrally moulded of a resin such as polyacetal resin.The coil winding portion 26 is encircled by a coil 27, and a terminal 28 is formed to rise from the terminal holding portion 25 by an integral moulding or press-fitting method. After the bobbin 24 has been attached to the E- or U-shaped back core 22, the front core 21 is attached to complete the head body 20.Next, the head body 20 is inserted into a bottom metal form or mould having a terminal hole 29 and tapered land 30 projecting inwardly. The terminal 28 is passed through the terminal hole 29 in the bottom form 31. The head body 20 is so inserted into the form 31 that the terminal holding portion 25 abuts the ridge of the taper land 30 at which point a top form or mould 32 is on the bottom form 31 to enclose the head body 20. After this, a resin 33 is injected to mould the head body 20, and so complete the magnetic head.
Figs. 2 and 3 are enlarged sections showing the taper land 30 before and after the resin moulding step, respectively. Before this step, the terminal holding portion 25 rides on the ridge of the taper land 30. If the resin is injected into the mould in this state, pressure is applied to the terminal holding portion 25 of the bobbin 24 by the resin injection so that the holding portion 25 is pressed into the taper land 30. If the bobbin 24 is moulded of a relatively soft resin, the ridge of the taper land 30 will bite slightly into the terminal holding portion 25. As a result, the resin 33 is prevented from flowing around the terminal 28 so that the terminal 28 moulded is freed from any resin coating.
As has been described hereinbefore, the magnetic head fabricating process, is one in which the magnetic core 23 is inserted into the mould having the terminal hole 29 and the taper lard 30 around the terminal hole 29 and by which the terminal holding portion 25 is brought into abutment against the taper land 30 to clog the terminal hole 29. As a result, the terminal itself of the head can be protected agaihst the attack of the mould and prevented from being buried by the resin thereby to improve the working efficiency and to fabricate a magnetic head of high quality and excellent workability.
Claims (4)
1. A magnetic head fabricating process comprising the steps of, forming a bobbin with a terminal holding portion having a terminal portion and a coil winding portion; mounting said bobbin in a magnetic core; inserting said magnetic core into a mould having a terminal hole provided with a land around said terminal hole; bringing said terminal holding portion into abutment with the land to close said terminal hole; and subsequently conducting a mould step to encapsulate at least partially the magnetic core.
2. A magnetic head fabricating process according to Claim 1, wherein said bobbin is made of a resin having such hardness that upon the application of pressure the taper land can bite into the contacting face of said terminal holding portion.
3. A magnetic head fabricating process substantially as hereinbefore described, with reference to Figs. 1 to 3 of the accompanying drawings.
4. A magnetic head when made by the process according to any preceding claim.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP60236988A JPH071523B2 (en) | 1985-10-23 | 1985-10-23 | Magnetic head manufacturing method |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8624945D0 GB8624945D0 (en) | 1986-11-19 |
| GB2183199A true GB2183199A (en) | 1987-06-03 |
| GB2183199B GB2183199B (en) | 1989-11-15 |
Family
ID=17008724
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8624945A Expired GB2183199B (en) | 1985-10-23 | 1986-10-17 | Processes for fabricating magnetic heads |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPH071523B2 (en) |
| KR (1) | KR900002969B1 (en) |
| GB (1) | GB2183199B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB493009A (en) * | 1937-08-13 | 1938-09-30 | Moulded Products Ltd | Improved method and means of glazing instrument cases and other structures having a transparent panel |
| GB564975A (en) * | 1942-12-21 | 1944-10-20 | Micro Switch Corp | Improvements relating to snap-action electric switches |
| GB619260A (en) * | 1946-11-28 | 1949-03-07 | John Cartner | Improvements in or relating to methods of and apparatus for moulding tyres on to toywheels |
| GB952209A (en) * | 1961-01-09 | 1964-03-11 | Henry And Thomas Ltd | Improvements relating to the production of moulded articles |
| GB959867A (en) * | 1962-08-03 | 1964-06-03 | Standard Telephones Cables Ltd | Insert elements for incorporation in synthetic resin mouldings |
| GB1421855A (en) * | 1973-01-23 | 1976-01-21 | Toko Inc | Method and apparatus for packaging electronic components with thermosetting material |
| GB1578313A (en) * | 1977-02-02 | 1980-11-05 | Fisker & Nielsen As | Method of manufacturing an electrical socket |
| EP0029491A1 (en) * | 1979-11-26 | 1981-06-03 | WOCO Franz-Josef Wolf & Co. | Moulding tool |
-
1985
- 1985-10-23 JP JP60236988A patent/JPH071523B2/en not_active Expired - Lifetime
-
1986
- 1986-05-06 KR KR8603511A patent/KR900002969B1/en not_active IP Right Cessation
- 1986-10-17 GB GB8624945A patent/GB2183199B/en not_active Expired
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB493009A (en) * | 1937-08-13 | 1938-09-30 | Moulded Products Ltd | Improved method and means of glazing instrument cases and other structures having a transparent panel |
| GB564975A (en) * | 1942-12-21 | 1944-10-20 | Micro Switch Corp | Improvements relating to snap-action electric switches |
| GB619260A (en) * | 1946-11-28 | 1949-03-07 | John Cartner | Improvements in or relating to methods of and apparatus for moulding tyres on to toywheels |
| GB952209A (en) * | 1961-01-09 | 1964-03-11 | Henry And Thomas Ltd | Improvements relating to the production of moulded articles |
| GB959867A (en) * | 1962-08-03 | 1964-06-03 | Standard Telephones Cables Ltd | Insert elements for incorporation in synthetic resin mouldings |
| GB1421855A (en) * | 1973-01-23 | 1976-01-21 | Toko Inc | Method and apparatus for packaging electronic components with thermosetting material |
| GB1578313A (en) * | 1977-02-02 | 1980-11-05 | Fisker & Nielsen As | Method of manufacturing an electrical socket |
| EP0029491A1 (en) * | 1979-11-26 | 1981-06-03 | WOCO Franz-Josef Wolf & Co. | Moulding tool |
Also Published As
| Publication number | Publication date |
|---|---|
| KR900002969B1 (en) | 1990-05-03 |
| KR870004399A (en) | 1987-05-09 |
| GB8624945D0 (en) | 1986-11-19 |
| JPS6297113A (en) | 1987-05-06 |
| JPH071523B2 (en) | 1995-01-11 |
| GB2183199B (en) | 1989-11-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |