Magnetic head and its production method

Abstract: There is disclosed an improvement of a magnetic head including a head core which comprises a first head core half body having a winding goove at one side surface thereof, and a second head core half body having at least one side surface, and in which the side surface of the first body is joined with the side surface of the second body, both bodies being fixed by mold glass about joined planes of the half bodies via a gap spacer having a melting point higher than the mold glass, and one end surface falling at right angle with the joined planes being shaped into an arc state to become a tape sliding surface having a magnetic gap at a joined portion of both bodies. In the configuration, the first half body comprises a back groove formed by cutting out a part nearby the other end surface opposite to the surface on which the sliding surface is formed, and a pair of first track width regulation grooves which are formed by cutting out of both corners of the joined plane thereof in a manner of having a slant of a predetermined angle from a portion nearby the opposite end to a direction of the sliding surface and being across the winding groove. The second half body comprises a pair of second track width regulation grooves cut out of both corners between the joined plane and the sliding surface on a slant of a predetermined angle from the middle the winding groove to the sliding surface. The mold glass is filled into the back groove and the first and second track width regulation grooves in order to fix the first and second half bodies by solidification after cooling.

Description: MAGNETIC HEAD AND ITS PRODUCTION METHOD BACKGROUND OF THE INVENTION The present invention relates to a magnetic head used in a magnetic recording/reproducing system, more particularly to a magnetic head having mold glass filled into a slot for regulating a track width thereof, and to a method for producing the above magnetic head. A conventional magnetic head is shown in FIGS. 1A to 1D. In the figure, a magnetic head 1 comprises magnetic core half bodies 2 and 3 made of ferromagnetic materials such as a single crystal ferrite of manganese and zinc, a gap spacer 4 attached to the half bodies 2 or 3, and a binder 5 for uniting the half bodies 2 or 3 with the other and made of solidified glass to which a mold glass is cooled and hardened. The half body 2 has a winding guide 2a which is cut off a part of the outer end from the body 2, a winding groove 2b cut out of a part of inner end wall thereof, and a pair of track width regulation grooves 2c which are cut out of top parts of both side corners of the body 2. The half body 3 has a winding guide 3a cut out of the outer end wall of the body 3, a back groove 3b cut out the bottom corner of the inner side of the body 3, and a pair of track width regulation grooves 3c which are cut out of top parts of top parts of both side corners of the body 3 corresponding to the grooves 2c. The head 1 has a tape sliding surface 1a formed at the upper surface thereof, and a magnetic gap 1b made by the gap spacer 4. The gap spacer 4 is formed in a thin layer and made of non-magnetic substances such as silicon oxide (SiO₂), aluminum oxide (Al₂O₃) or the like, which are harder than the glasses and have a high melting point. On the sliding surface 1a, a track width regulation portion is formed by the grooves 2c and 3c for regulating a track width of a magnetic tape (not shown). As the gap spacer 4 lies between the upper portions of the half bodies 2 and 3, the gap spacer 4 causes the bodies 2 and 3 to have an angle of theta degrees. Mold glass pieces 5 are caulked in the back groove 3b and the regulation grooves 2c and 3c, respectively. A gap 6 at an angle of theta degrees is formed between the inside surfaces of the bodies 2 and 3 by the gap spacer 4 as if the magnetic gap 1b is extended downward in the figures. The magnetic head 1 having the above configuration is manufactured by a method including the following steps. At first, two pole-shaped materials respectively corresponding to five or six half bodies 2 and 3 are provided and a spacer material corresponding to five or six gap spacers 4 is located between upper portions of core materials. At this time, two long grooves have been already formed at predetermined portions of the inside and outside surfaces of the material of the body 2 in the longitudinal direction respectively corresponding to the guide 2a and groove 2b. Two long grooves have been already formed at predetermined portions of the inside and outside surfaces of the material of the body 3 in the longitudinal direction respectively corresponding to the guide 3a and back groove 3b, also. Secondly, glass rods which melt at a predetermined temperature are respectively allotted to positions coresponding to the regulation grooves 2c and 3c. The same glass rod is allotted to a position corresponding to the back groove 3b. Then, the glass rods are melted by adding at a predetermined temperature while the materials continue to have a predetermined angle theta. As the glass is cooled down and solidified after melting, the materials are fixed by the solidified glass material. Lastly, after an upper surface of the materials connected in a pole-shaped body is polished and shaped in an arc, the materials are cut in five or six pieces having a predetermined width. After that, the magnetic head 1 shown in FIGS. 1A to 1D is completed. The magnetic head 1, which has the aforementioned configuration and is manufactured by the above method, is formed in the manner of having the magnetic gap 1b, so that the gap 6 must be formed at a lower joint plane of the half bodies 2 and 3. The head 1 has a problem that the gap 6 causes the head 1 to form a crack 7, thereby generating a problem of a large deterioration in the mechanical strength. In order to prevent the crack occurring in the above example, there is proposed a magnetic head 10 according to another conventional example as shown in FIGS. 2A to 2D. The head 10 comprises half bodies 12 and 13 respectively corresponding to the bodies 2 and 3, and which are joined by a binder 15 corresponding to the binder 5 of the head 1 shown in FIGS. 1A to 1D. Accordingly, the half bodies 12 and 13 have winding guides 12a and 13a and winding grooves 12b and 13b, respectively. Furthermore, both sides along joined end surfaces of the bodies 12 and 13 are cut out to form uniting grooves 12c and 13c in which the binder 15 is plugged. An upper surface of the head 10 is formed into an arc shape to become a tape sliding surface 10a, and a track regulation groove is formed by the binder 15. A magnetic gap 10b is formed by a united plane of the bodies 12 and 13 on the sliding surface 10a in the same manner as the aforementioned example shown in FIGS. 1a to 1D. As the magnetic head 10 according to a prior art substantially corresponding with JP 4-39124 and JP 4-5046 and shown in FIGS. 2A to 2D is manufactured by substantially the same steps as those of the head 1 shown in FIGS. 1A to 1D, duplicate explanation is omitted. In the example, as shown in FIG. 2C which is a cross sectional view of FIG. 2A on a cutting line II-II, though the binder 15 after solidificatiuon of the mold glass is provided around the lower united plane of the bodies 12 and 13, the head 10 has a problem that a gap 16 is formed between the bodies 12 and 13. As a joined area of a back gap portion, that is, the lower united area between the bodies 12 and 13 becomes smaller, a magnetic reluctance becomes larger, so that the head 10 has the problem of the magnetic characteristics deteriorating. The magnetic head 10 is not only used as the complete head having a single magnetic gap 10b shown in FIG. 2D, but also as a so-called double azimuth head comprising two heads which are cut off at cutting lines 17 of the bodies 13, as represented by dotted line shown in FIG. 2D, respectively, and set on a base (not shown). In the case that the heads 10 are used in the double azimuth head, it is possible to cut off the back grooves 13b when the bodies 13 are cut, because the distance between the cutting line 17 and the back groove 13b is insufficient. Therefore, the head 10 involves the problem of checking the workability of the manufacture of the head. The former head 1 has a crack 7 or the like and has a smaller joined area of the half bodies, as mentioned before, so that the head 1 has the problem of a deteriorated magnetic resistance and other magnetic characteristics. From Patent Abstracts of Japan, Vol. 10, No. 152 (P-462) [2208], June 3, 1986; & JP-A-61-5406 (Hitachi Seisakusho K.K.) a magnetic head is disclosed, comprising the features of the precharacterizing portion of claim 1, namely a head core which comprises a first head core half body having a winding groove at one side surface thereof, and a second head core half body having at least one side surface, and in which the side surface of the first body is joined with the side surface of the second body, both bodies being fixed by mold glass about joined planes of the half bodies via a gap spacer having a melting point higher than the mold glass and one end surface falling at right angle with the joined planes is shaped into an arc to become a tape sliding surface having a magnetic gap at a joined portion of both bodies, said head comprising the first half body having a back groove formed by cutting out a part nearby the other end surface opposite to the surface on which the sliding surface is formed, or by cutting the corner between the joined plane of said first half body and said other end surface; and a pair of first track width regulation grooves which are formed by cutting out both corners of the joined plane thereof in a manner of having a slant of a first predetermined angle; the second half body having a pair of second track width regulation grooves cut out both corners between the joined plane and the sliding surface on a slant of a second predetermined angle from the winding groove to the sliding surface; and the mold glass which is filled into the back groove and the first and second track width regulation grooves; in order to fix the first and second half bodies by a solidification after cooling. In order to provide a sufficient adhesion strength between the core half bodies glass is not only filled into the back groove for reinforcing the core back portion and into the first and second track width regulation grooves but is additionally used in form of a glass film for joining the contact portions of the head core half bodies between the winding groove and the back groove. This glass film has to be formed in an additional method step by spattering and disadvantageously increases the magnetic resistance of the head. SUMMARY OF THE INVENTION The present invention is created to solve the aforementioned problems, and an object of this invention is to provide a magnetic head having enough mechanical strength and excellent magnetic characteristics by holding enough united area of the back gap portion. Furthermore, another object of this invention is to provide a production method for a magnetic head capable of manufacturing such an excellent head rapidly and suitably. In order to achieve the above problems, the magnetic head according to the present invention is characterized in that said first track width regulation grooves are cut with a slant of said first predetermined angle starting from a portion nearby said end surface opposite to the sliding surface and being across the winding grooves such that said grooves contain parts between said back groove and said winding groove. Furthermore, the production method of the magnetic head according to the present invention comprises a step of cutting out a second deep-and-long groove corresponding to the back groove of a completed head and parallel to a first deep-and-long groove corresponding to the winding groove of a completed head on a joined plane of a first core half body material which is made of a ferromagnetic substance and corresponding to a plurality of first magnetic core half bodies; a step of cutting a plurality of first notches corresponding to the first track width regulation grooves with said slant of said first predetermined angle starting from portions nearby the second deep grooves to the surface of a side of the first deep grooves being across the first deep grooves such that said first notches contain parts between said back groove and said winding groove; a step of cutting a plurality of second notches corresponding to the first notches on a joined plane of a second core half body material which is made of a ferromagnetic substance and corresponding to a plurality of second magnetic core half bodies for forming said second track width regulation grooves; a step of connecting the first material with the second material at both joined surfaces by causing the first and second notches to correspond each other; a step of fixing the first and second materials by means of the mold glass after cooling and solidification of melted glass which is molded into the second deep grovve and the first and second notches; a step of regulating the whole shape of a joined body by adding a predetermined treatment to a predetermined outer surface; and a step of dividing the joined body into a plurality of magnetic heads having a predetermined shape by slicing at portions of the notches. As the magnetic head having the aforementioned configuration has the first and second bodies which are sufficient to maintain the back gap and are properly fixed between the joined planes of both bodies, it is 20 possible to prevent the occurrence of damage such as cracking of the joined surfaces of the half bodies and thus assure mechanical strength. Furthermore, as the magnetic head is manufactured by the aforementioned steps it is possible to properly 25 connect and fix the first and second half body materials to each other and thereby improve a manufacturing yield. Still furthermore, as the head having a complicate shape is manufactured by simple steps, it is possible to reduce the manufacturing cost of the magnetic head. Preferably, said slant starts from a point substantially at said opposite end surface or, alternatively, from a point at the upper corner of the back groove. Preferable values of the first and seond predetermined angles for certain first and second embodiments described later are characterized in subclaims 4 to 6. BRIEF DESCRIPTION OF THE DRAWINGS In the accompanying drawings: FIGS. 1A to 1D are a front view, plan view, a cross sectional view cut off from line I-I, and a perspective view, respectively, showing an example of a conventional magnetic head; FIGS. 2A to 2D are a front view, plan view, a cross sectional view cut off from line II-II, and a perspective view, ewspectively, showing another example of a conventional magnetic head; FIGS. 3A to 3D are a front view, plan view, cross sectional view cut off from line III-III, and a perspective view, respectively showing a magnetic head according to a first embodiment of the present invention; FIGS. 4A to 4F are perspective views respectively showing manufacturing steps of the magnetic head according to the first embodiment of the present invention; FIGS. 5A to 5D are a front view, plan view, a cross sectional view cut off from V-V line, and a perspective view, respectively showing a magnetic head according to a second embodiment of the present invention; FIGS. 6A to 6F are perspective views respectively showing manufacturing steps of the magnetic head according to the second embodiment of the present invention; FIG. 7 is a front view showing a magnetic head according to a third embodiment of the present invention; and FIG. 8 is a front view showing a magnetic head according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS There are described in detail hereinafter preferred embodiments of a magnetic head and its production method according to the present invention with reference to accompanying drawings. In FIGS. 3A to 3D showing a first embodiment of this invention, a magnetic head 20 schematically comprises a first and a second core half bodies 22 and 23 made of ferromagnetic materials such as a ferrite of manganese and zinc or the like, and mold glass 25 for fixing the first and second bodies 22 and 23. One of the outer wall surfaces, which fall at right angles with a joined plane between the half bodies 22 and 23, is formed in an arc to become a tape sliding surface 20a on which a magnetic gap 20b is formed, as shown in FIG. 3B. The magnetic gap 20b, as shown in FIG.3C, is concretely made by a gap spacer 24 such as quartz member attached to any uniting surface of half body 22 or 23. The gap spacer 24 is made of a non-magnetic substance such as SiO₂ or Al₂O₃ having a high melting point. The first half body 22 having a substantially rectangular solid as a whole form, comprises a winding guide 22a which is shallowly cut out of a part of the oppsite wall with the uniting surface, a winding groove 22b which is deeply cut out of a part of the uniting surface corresponding to the guide 22a, a back groove 22c which is deeply cut out of a part of the uniting surface near a corner of the opposite side with the sliding surface and parallel to the groove 22b, and first track width regulation grooves 22d which are cut out of both corners of the uniting surface in the manner that the grooves 22d slant in a predetermined angle DEG₁ from a starting point 21 to the sliding surface across the back groove 22c and the guide groove 22b. A back gap portion 22e is formed by cutting the grooves 22d and existence of the gap spacer 24 and has a shape shown in FIG. 3C. The second half body 23 has also a substantially rectangular solid corresponding to the body 22. The body 23 comprises a winding guide 23a which is cut out of a part of the opposite wall surface with a uniting surface to the body 22, and second track width regulation grooves 23b which are slantly cut out of both corners of the sliding surface side of the uniting surface of the body 23 in a predetermined angle DEG₂. The mold glass 25 has three portions 25a, 25a and 25b in the first embodiment corresponding to the back groove 22c, the first and the second regulation grooves 22d and 23b, respectively, which are formed on the first and second half bodies 22 and 23. The portions 25a and 25a are shaped in an arrowhead to fit for portions of the sliding surface side of the first regulation grooves 22d and the second regulation grooves 23b, while the portion 25b has a rectangular part to fit for the back groove 22c and two projecting parts to fit for under portions of the first regulation grooves 22d. In the first embodiment, four degrees are proper for the angle DEG₁, and fifteen degrees are best suited for the angle DEG₂. Testing the head after completion proves that these degrees are best mode for the angles. Furthermore, actual articles have sizes where a distance D₁ is 0.14 mm plus or minus 0.02 mm and equal to a distance D₂, a distance D₃ is about 0.05 mm, and a distance D₄ is about 1.5 mm. Articles having this size are the best mode for the utilization. Next, there is described a production method of the magnetic head 20 according to the first embodiment and with reference to FIGS. 4A to 4F. At first, there are provided a first material 26 which is made of a ferromagnetic substance such as a ferrite of manganese and zinc, and which has a pole-shaped body corresponding to five or six articles of the first core half bodies 22, and a second material 27 which are also made of a ferromagnetic substance and has a pole-shaped body corresponding to five or six articles of the second core half bodies 23. The first material 26, as shown in FIG. 4A, has a shallow-and-long groove 26a formed on a outer wall 26A which is the opposite wall with a uniting surface 26B, and a deep-and-long groove 26b formed on the uniting surface 26B. The grooves 26a and 26b respectively correspond to the winding guide 22a and the winding groove 22b when the heads are completed as articles. The material 27 also has a shallow-and-long groove 27a which is formed on an outer wall 27A as the oppsite surface with a uniting surface 27B corresponding to the winding guide 23a of the completed head 20. Though the step of cutting out the long grooves 26a, 26b and 27a is the first step of making the head 20, because a conventional production method includes the same or equivalent step as the first step, the groove cutting step is only a preliminary and featureless step in this invention. In the next step of this method, a deep-and-long groove 26c is formed on the uniting surface 26B nearby outer wall 26D, as shown in FIG. 4B, which is parallel with the long groove 26b and becomes the back groove 22c when the head 20 is completed. Next, a plurality of notches 26d are formed on a surface between the groove 26b and the surface 26C by cutting out several portions of the uniting surface 26B in the right cross direction to the groove 26b. In the example shown in the figures, five complete notches and two half notches are cut in order to produce six articles. A plurality of notches 26e are formed on a surface between grooves 26b and 26c as if the notches 26d are extended to the corner of the surface 26D by the same manner as the notches 26d. The nearer the notches 26d and 26e get to a corner of the surface 26C, the broader and deeper they are. On the other hand, a plurality of notches 27b are formed at a corner between a uniting surface 27B and a surface 27C corresponding to the notches 26d. In this example, five complete and two half notches 27b are formed in the same manner as the notches 26d and 26e. Then, the gap spacers 24 are attached with a predetermined thickness to partial surfaces of the uniting surface 26B surrounded by the notches 26d and the groove 26b by spattering quartz or the like. Both materials 26 and 27 are interconnected at the uniting surfaces 26B and 27B according to an arrow of a dot-and-dash line shown in FIGS. 4A and 4B and temporarily fixed to become a united body 28. After that, glass rods 29a and 29b are inserted into the grooves 26b and 26c,respectively, as shown in FIG. 4C. The glass rods 29a and 29b are set to the predetermined positions. The united body 28 is then inverted and the glass is melted to plug the back groove 26c and the notches 26d, 26e and 27b. Full plugged glass is cooled to a predetermined temperature to solidify and become solid-state glass pieces 29A and 29B shown in FIG. 4D as a binder, so that the united body 28 is properly fixed in one body. A curved surface 28a is formed by cutting or polishing to become the tape sliding surface after articles complete at an upper surface in the figures corresponding to the surfaces 26C and 27C of the materials 26 and 27. The united body 28 is sliced into a plurality of magnetic heads 20A to 20F having a predetermined size and so as to obtain the desired articles. FIG. 4E is a perspective view showing a complete magnetic head as an article, and corresponds to the exploded perspective view shown in FIG. 3D if the head 20 is exploded for the sake of convenience. Although the magnetic head 20 is completed in the first place through the aforementioned steps shown in FIGS. 4A to 4E, a reprocessed head 20 shown in FIG. 4F is produced by cutting the half body 23 at a dotted line 23c in FIG. 4E in continued steps according to request. When two reprocessed heads 20 are assembled on a base (not shown) in the manner of facing the cut surfaces 23d each other, it is possible to obtain the so-called double azimuth head (as mentioned in the explanation of the prior art) having two magnetic gaps. Although the back groove 22c is described as a deep groove which is formed by leaving the corner between the uniting surface corresponding to 26B and the opposite surface with sliding surface 20a, the present invention is not limited to such a configulation and may have a configuration of a magnetic head 30 according to a second embodiment as shown in FIGS. 5A to 5D. In the figures, the numerals 32, 33 and 35 are equivalent to the half bodies 22 and 23 and the fixing glass 25 in FIGS. 3A to 3D. The head 30 also has a tape sliding surface 30a and a magnetic gap 30b. The body 32 has a winding guide 32a, a winding groove 32b, a back groove 32c, and a first regulation groove 32d, as shown in FIG. 5D. A gap spacer 34 is attached on a joined plane batween the half bodies 32 and 33, so that a back gap 32e remains between the grooves 32b and 32c. The spacer 34 is made of quartz or the like and has a suitable thickness such as 0.3 micron. The half body 33 has a winding guide 33a and a second regulation groove 33b. The second embodiment is different from the first embodiment in the several points as follows. The back groove 32c is formed by cutting the corner between the uniting surface of the body 32 and the opposite surface with the sliding surface 30a. Two portions 35a and 35a of the mold glass 35 are larger than the portions 25a and 25a of the first embodiment on the basis that the second regulation grooves 33b and 33b are deeply cut out. The portions 35a and 35a are connected with an under portion 35b through a curved portion 35c. An opening portion 35d is provided between both pole-shaped portions of the under portion 35b. The back gap portion 34b is located at the opening portion 35d. There will now be described a production method of the magnetic head 30 according to the second embodiment with reference to FIGS. 6A to 6F. As shown in FIG.6A, a first shallow-and-long groove 36a and a first deep-and-long groove 36b are formed on a first material 36 for the half body 32, which become the guide 32a and the groove 32b for winding, respectively. At the same time, a second shallow-and-long groove 37a is formed on a second material 37 to become the second winding guide 33a. Numerals 36B and 37B are the uniting surfaces of both materials 36 and 37. Both materials 36 and 37 are made of ferromagnetic substance such as a ferrite of manganese and zinc. Next, as shown in FIG. 6B, a corner of the surface 36B and a surface 36D is cut along the groove 36b to hollow a second deep-and-long groove 36c corresponding to the back groove 32c. Then, a plurality of notches 36d are formed on a surface between the groove 36b and the surface 36C by cutting out several portions of the uniting surface 36B in the right cross direction to the groove 36b. A plurality of notches 36e are formed on a surface between grooves 36b and 36c as if the notches 36d are extended to the corner of the surface 36D by the same manner as the notches 36d. The notches 36d and 36e correspond to the notches 26d and 26e, respectively, in the first embodiment shown in FIG. 4B. Then, the gap spacers 34 are attached with a predetermined thickness such as 0.3 micron to partial surfaces of the uniting surface 36B surrounded by the notches 36d and the groove 36b by spattering quartz or the like. On the other hand, a plurality of notches 37b are formed at a corner between a uniting surface 37B and a surface 37C corresponding to the notches 36d. The notches 37b become the second track regulation groove 33b. Next, a united body 38 is formed by interconnection of the uniting surfaces 36B and 37B with the coincidence of the notches 36d and 37b, as shown in FIG. 6C. In the united body fixed temporarily, glass rods 39a and 39b are inserted into the deep grooves 36b and 36c. The unitedbody 38 is then inverted and the glass is melted to plug the back groove 36c and the notches 36d, 36e and 37b. Then, the united body 38 is cooled to a predetermined temperature, so that both materials 36 and 37 are completely fixed by a solid-state glass body 39A which hardens by cooling. After that, as shown in FIG. 6D, a curved surface 38a of the body 38 is shaped, which becomes the tape sliding surface 30a after completion. The body 38 is sliced into a plurality of magnetic heads 30A to 30F according to the article's size in the same manner as shown in FIG. 4D, so that six heads are obtained. Also, in the second embodiment, if the head 30 is cut out by the dotted line 33c, a head half body for the double azimuth head shown in FIG. 6F is obtained. When two half bodies each having a cutting surface 33d are assembled on the base with facing the surfaces 33d, the double azimuth head is completed. In the magnetic head 30 of the second embodiment, an angle DEG₁ is four or five degrees and an angle DEG₂ is fifteen degrees. Though the track regulation groove 22d is set to have the angle DEG₁ of 4 degree from the starting point 21 in the head 20 of the first embodiment, the present invention is not limited in this configuration. For example, in a third embodiment shown in FIG. 7, a magnetic head 40 is cut to a slant of 5 degrees from an upper corner of a back groove 42c as a starting point 41. Other elements of the head 40 according to the third embodiment are the same as the head 20 of the first embodiment. An angle DEG₂ for setting the second regulation groove 43b is fifteen degrees in the same angle as head 20 of the first embodiment. Furthermore, the magnetic head 50 of a fourth embodiment shown in FIG.8, has a first track regulation groove 52d which is cut out from the starting point 51 to an angle DEG₁ of 3.5 degrees. As described in detail, since the magnetic head according the present invention is sufficient to maintain the back gap and proper condition of fixing the half bodies it is possible to prevent an occurrence of damage such as cracking of the joined surfaces of the half bodies and to assure mechanical strength. Furthermore, by the production method of the magnetic head according to the present invention it is possible to properly connect and fix the first and second half body materials to each other and thereby improve the manufacturing yield. Still furthermore, as a head having a complicated shape is manufactured by simple steps, it is possible to reduce the manufacturing cost of the magnetic head.

Claims: A magnetic head including a head core (20) (30) (40) (50) which comprises a first head core half body (22) (32) (42) (52) having a winding groove (22b) (32b) (42b) (52b) at one side surface there-of, and a second head core half body (23) (33) (43) (53) having at least one side surface, and in which the side surface of the first body is joined with the side surface of the second body, both bodies being fixed by mold glass (25) (35) about joined planes of the half bodies via a gap spacer (24) (34) having a melting point higher than the mold glass and one end surface falling at right angle with the joined planes is shaped into an arc to become a tape sliding surface (20a) (30a) (40a) (50a) having a magnetic gap (20b) (30b) (40b) (50b) at a joined portion of both bodies, said head comprising the first half body (22) (32) (42) (52) having a back groove (22c) (32c) (42c) (52c) formed by cutting out a part nearby the other end surface opposite to the surface on which the sliding surface is formed, or by cutting the corner between the joined plane of said first half body (22) (32) (42) (52) and said other end surface; and a pair of first track width regulation grooves (22d) (32d) (42d) (52d) which are formed by cutting out both corners of the joined plane thereof in a manner of having a slant of a first predetermined angle (DEG₁) ; the second half body (23) (33) (43) (53) having a pair of second track width regulation grooves (23b) (33b) (43b) (53b) cut out both corners between the joined plane and the sliding surface on a slant of a second predetermined angle (DEG₂) from the winding groove (22b) (32b) (42b) (52b) to the sliding surface; and the mold glass (25) (35) (45) (55) which is filled into the back groove (22c) (32c) (42c) (52c) and the first and second track width regulation grooves (22d,23b) (32d,33b) (42d,43b) (52d,53b) ; in order to fix the first and second half bodies (22,23) (32,33) (42,43) (52,53) by a solidification after cooling characterized in that said first track width regulation grooves (22d) (32d) (42d) (52d) are cut with a slant of said first predetermined angle (DEG₁) starting from a portion (21) (41) (51) nearby said end surface opposite to the sliding surface and being across the winding groove (22b) (32b) (42b) (52b) such that said grooves contain parts (26e) (36e) between said back groove (22c, 32c, 42c, 52c) and said winding groove (22b, 32b, 42b, 52b). A magnetic head according to claim 1, wherein said slant starts from a point (21, 51) substantially at said opposite end surface. A magnetic head according to claim 1, wherein said slant starts from a point (41) at the upper corner of the back groove (42c). A magnetic head as set forth in claim 1, wherein said first track width regulation groove(22d) (32d) (42d) (52d) formed on the first half body (22) (32) (42) (52) is cut out across said winding groove (22b) (32b) (42b) (52b) to said sliding surface (20a) (30a) (40a) (50a) with said slant which has the angle (DEG₁) of 4 degrees and starts from a cross portion of an opposite surface with said sliding surface and a joined plane of both half bodies, and said second track width regulation groove (23b) (33b) (43b) (53) formed on the second half body(23) (33) (43) (53) is cut out at said slant from a middle of said winding groove (22b) (32b) (42b) (52b) to said sliding surface with the angle (DEG₂) of 15 degrees. A magnetic head as set forth in claim 1, wherein said first track width regulation groove (22d) (32d) (42d) (52d) formed on the first half body (22) (32) (42) (52) is cut out across said winding groove (22b) (32b) (42b) (52b) to said sliding surface (20a) (30a) (40a) (50a) with said slant which has the angle (DEG₁) of 5 degrees and starts from a cross portion of an opposite surface with said sliding surface and a joined plane of both half bodies, and said second track width regulation groove (23b) (33b) (43b) (53b)formed on the second half body(23) (33) (43) (53) is cut out at said slant from a middle of said winding groove(22b) (32b) (42b) (52b) to said sliding surface with the angle (DEG₂) of 15 degrees. A magnetic head as set forth in claim 1, wherein said first track width regulation groove (22d) (32d) (42d) (52d) formed on the first half body (22) (32) (42) (52) is cut out across said winding groove (22b) (32b) (42b) (52b) to said sliding surface with said slant which has the angle (DEG₁) of 3.5 degrees and starts from a point distant from an opposite surface with said sliding surface (20a) (30a) (40a) (50a) and extended from a joined plane of both half bodies, and said second track width regulation groove (23b) (33b) (43b) (53b) formed on the second half body (23) (33) (43) (53) is cut out at a slant from a middle of said winding groove (22b) (32b) (42b) (52b) to said sliding surface (20a) (30a) (40a) (50a) with the angle (DEG₂) of 15 degrees. A head as set forth in anyone of claims 2 to 4, said back groove (22c) (32c) (42c) (52c) of said first core half body (22) (32) (42) (52) is formed in condition that said opposite surface of the sliding surface (20a) (30a) (40a) (50a) remaines. A production method of the magnetic head according to claim 1 comprising a step of cutting out a second deep-and-long groove (26c) (36c) corresponding to the back groove (22c) (32c) of a completed head (20) (30) and parallel to a first deep-and-long groove (26b) (36b) corresponding to the winding groove (22b) (32b) of a completed head on a joined plane of a first core half body material (26) (36) which is made of a ferromagnetic substance and corresponding to a plurality of first magnetic core half bodies (22); a step of cutting a plurality of first notches (26d, 26e) (36d, 36e) corresponding to the first track width regulation grooves with said slant of said first predetermined angle (DEG₁) starting from portions nearby the second deep grooves (26c) (36c) to the surface of a side of the first deep grooves (26b,26e) (36b,36e) being across the first deep grooves (26b,26e) (36b,36e) such that said first notches contain parts (26e,36e) between said back groove (22c) (32c) and said winding groove (22b) (32b), a step of cutting a plurality of second notches (27b) (37b) corresponding to the first notches (26d) (36d) on a joined plane of a second core half body material (27) (37) which is made of a ferromagnetic substance and corresponding to a plurality of second magnetic core half bodies (23) (33) for forming said second track width regulation grooves; a step of connecting the first material (26) (36) with the second material (27) (37) at both joined surfaces (26B, 27B) (36B,37B) by causing the first and second notches (26d,26e,27b) (36d,36e,37b) to correspond each other; a step of fixing the first and second materials (26, 27) (36,37) by means of the mold glass after cooling and solidification of melted glass (29a,29b) (39a,39b) which is molded into the second deep groove (26c) (36c) and the first and second notches (26d, 26e,27b) (36d,36e,37b); a step of regulating the whole shape (28a) (38a) of a joined body (28) (38) by adding a predetermined treatment to a predetermined outer surface; and a step of dividing the joined body (28) (38) into a plurality of magnetic heads (20A to 20F) (30A to 30F) having a predetermined shape by slicing at portions of the notches (26d,26e,27b) (36d,36e,37b). A production method as set forth in claim 8, further comprising a step of making a gap spacer (24) (34) which is attached by spattering a non-magnetic substance having a melting point higher than the mold glass on the united surface (26B) (36B) of the first material (26) (36) surrounded by said deep groove (26b) (36b) and said first notches (26d) after said step of forming the first notches (26d). A production method as set forth in claim 8, further comprising a step of making a magnetic head (20) (30) for a double azimuth head by cutting out the portion (23c) (33c) of the winding guide (23a) (33a) side of said second core half body (23) (33) after the step of slicing said joined body (28) (38) into a plurality of heads (20A to 20F) (30A to 30F).

Inventors: KOHARA SOHEI, KOSEKI MAKOTO - VICTOR SHATAKU, NEMOTO KOJI, TSUTSUI TAKASHI - VICTOR SHATA, KOHARA, SOHEI,, KOSEKI, MAKOTO, 2-221, VICTOR SHATAKU, NEMOTO, KOJI,, TSUTSUI, TAKASHI, 2-241, VICTOR SHATAKU
Applicants: VICTOR COMPANY OF JAPAN, VICTOR COMPANY OF JAPAN, LIMITED
Application year: 1990
Main classification: G11B5
IPC codes: G11B5