JP3413727B2 - Rotary magnetic head device and drum manufacturing method for rotary magnetic head device - Google Patents

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 used in a VTR, a DAT or the like, and a method for manufacturing a drum of the rotary magnetic head device.

[0002]

2. Description of the Related Art A conventional rotary magnetic head device of this type is
For example, the configuration is as shown in FIGS. 8 and 9. In FIG. 8, the rotary magnetic head device includes an upper drum 18 and
A lower drum 11 and a rotating drum 14 are provided. The upper drum 18 and the lower drum 11 are fixed drums, and the rotary drum 14, which is also called a middle drum, is rotatable about the center of rotation shown in FIG.

A magnetic head 13 is provided on the rotary drum 14. The magnetic tape 1 is guided by the S-side guide 6 and the T-side guide 7 and runs obliquely along the direction of the arrow with respect to the rotary drum 14. Then, the magnetic head 13 of the rotary drum 14 can record or read information by helicopting the magnetic tape 1.

[0004]

However, such a rotary magnetic head device has the following problems. Figure 8
As shown in FIG. 9, the rotary drum 14 is configured to rotate about the rotation center C. As shown in FIG.
When the rotating drum 14 is rotated at high speed, the rotating drum 14 entrains air, and the surroundings of the rotating drum 14 and the magnetic tape 1
The air film A indicated by diagonal lines is generated between and.

The area where the air film A is generated is distributed thickly on the S side guide 6 side of the tape supply side where the tape tension is low and the surface in contact with the rotary drum 14 is large, and the surface where the tape tension is high and the surface in contact with the rotary drum 14 is large. Is distributed thinly on the T-side guide 7 side of the tape feeding side having a small value. Therefore, as shown in FIG. 9, the running center P1 of the magnetic tape 1 is eccentric from the rotation center C of the rotating drum 14 by the difference in the amount of the generation area of the air film A.

The magnetic tape 1 is pressed along the leads 9 of the lower drum 11 by the S-side guide 6 and the T-side guide 7, but near the center of the leads 9 formed on the lower drum 11, Since there is no mechanism for pressing the magnetic tape 1 from above, the magnetic tape 1 easily floats from the lead 9.

Therefore, in order to average the generation area of the air film A and obtain the pressing force of the tape 1 to the lead 9, the cylindricity of the upper drum 18 and the lower drum 11 is
A portion corresponding to the S-side guide 6 of the upper drum 18, a central portion,
And in the part corresponding to the T side guide 7 of the drum,
It is necessary to assemble them so that they have different numbers. The cylindricity means the distribution of the diameter difference between the upper drum 18 and the lower drum 11 in the circumferential direction of the rotary drum 14.

[0008] For example, in one example, the central portion is maximum,
Next, it is necessary to reduce the diameter difference between the upper drum 18 and the lower drum 11 in the order of the T-side guide 7 side and the S-side guide 6 side.

In the conventional rotary magnetic head device, as shown in FIG. 10, a head assembly having a magnetic head 14 on a flange portion 12a of a head rotation drive shaft 12 which is coaxially provided through the lower drum 11 is also used. The rotating drum 13 is attached by screwing it into the screw hole 12b with bolts 14a and 14a.

Next, as shown in FIG. 11, the upper drum 18
Is attached to the drum support 15 with bolts 17, 17, and the drum support 15 is attached to the lower drum 11 with bolts 16, 17.
Attach by 16.

The bolt 16 has a hole 15a in the drum support 15.
Through the hole 11a of the lower drum 11 shown in FIG. In this state, the lower drum 11 and the drum support 15
The spacer 19 for adjusting the cylindricity is inserted between the lower drum 11 and the drum support 15 from the side of the contact surface.

At this time, the bolt 16 is set in a slightly loosely fitted state so that the cylindricity adjusting spacer 19 can be easily inserted. Then, the cylindricity of the upper drum 18 and the lower drum 11 is measured with the bolts 16 and 16 properly tightened, and if the value is within the standard, the assembly is completed.

Conventionally, when the upper drum 18 and the lower drum 11 which are processed into a substantially perfect circle are used, a spacer 19 is always provided between the lower drum 11 and the drum support 15 as shown in FIGS. It is necessary to sandwich it. When the spacer 19 is forcibly sandwiched in this way, as shown in FIG. 12, the rotation center C of the rotary drum 13 and the center P1 of the upper drum 18 are not coaxial but eccentric. As a result, the tape 1 is forcibly lifted by the upper drum 18 to improve the hitting property of the tape 1.

As described above, according to the conventional method, the spacer 19 is inserted in this way and the cylindricity of the upper drum 18 and the lower drum 11 is repeatedly measured to correspond to the S side guide 6 side shown in FIG. Part and the part corresponding to the central part,
Then, the accuracy of the portion corresponding to the T-side guide 7 had to be within the standard.

However, in such a method, when the tape lag angle is 180 ° or more, in principle, the cylindricity on the S side guide 6 side or the T side guide 7 side of the upper drum 18 shown in FIG. Was impossible.

The present invention has been made in order to solve the above problems, and a rotary magnetic head device and a rotary magnetic head capable of omitting an adjusting step for obtaining a predetermined cylindricity and greatly shortening the time. It is an object of the present invention to provide a drum manufacturing method for an apparatus.

[0017]

The above object is, in the invention of claim 1, that the upper drum and the lower drum are supported by the drum support.
A fixed drum that supported me, said on the soil medium drum
In a rotary magnetic head device that is a rotary drum that rotates between a ram and the lower drum , a tool is moved in a radial direction perpendicular to the main shaft and an axial direction of the main shaft in synchronization with rotation of the main shaft of the upper drum. By forming the tape running surface of the upper drum, when viewed from the axial direction of the main shaft of the upper drum, the tape in the upper drum and the lower drum
The section supported by the drum support has a substantially circular cross section.
Formed on the outer peripheral surface of the cylinder, and by the drum support
The part of the upper drum that is not supported is the drum support.
Compared to the lower drum part which is not supported by
Te, the central region of the tape running surface of the upper drum overhanging the largest, followed by the larger outlet area of the tape in the tape running surface, so that the inlet region of the tape in the tape running surface is smaller than the outlet area And a rotary magnetic head device characterized by being formed by the tool in response to the uneven distribution of the air film generated between the rotating peripheral surface of the middle drum and the running tape. .

[0018]

In the invention of claim 2 , preferably the front
The shape of the outer peripheral surface of serial on the drum is formed to fit the cylindrical degree of the lower drum and the upper drum.

In the invention of claim 3, the outer peripheral surface of the upper drum is preferably formed by changing the wall thickness. In the invention of claim 4, the shape of the outer peripheral surface of the upper drum is preferably formed by molding.

[0021]

[0022]

According to the above structure, the outer peripheral surface of the fixed drum has a substantially circular shape when viewed from the axial direction of the main shaft of the upper drum. Is the largest, then the tape outlet area on the tape running surface is large, and the tape is formed such that the vicinity of the tape entrance on the tape running surface is smaller than the exit area. Since the air film is molded according to the uneven distribution of the air film that occurs between the air films, the distribution of the air film becomes uniform. In addition, this rotary magnetic head device
Of the part supported by the drum support in the lower drum
Since the cross section is composed of the outer peripheral surface of a cylinder that is almost a perfect circle,
Assembled to support the drum and the lower drum with the drum support
In this case, the upper and lower drums can be accurately aligned.
Will be forced to.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that the examples described below are suitable specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 is a perspective view showing a rotary magnetic head device of the present invention. This rotary magnetic head drum device includes an upper drum 118, a lower drum 111, and a rotating drum 114.
Is equipped with. The upper drum 118 and the lower drum 111 are fixed drums. The rotary drum 114 is an intermediate drum, and the rotary drum 114 is provided with, for example, two magnetic heads 113. The two magnetic heads 113 are arranged at opposite positions in the diametrical direction.

The rotary drum 114 is rotatably provided on the fixed drum 111, and the upper drum 118 also called a fixed drum and the lower drum 111 also called a fixed drum are held by the drum support 100.

Referring to FIG. FIG. 2 shows the relationship between the upper drum 118 and the lower drum 111, particularly the cylindricity. The outer peripheral surface of the lower drum 111 has a substantially circular shape. On the other hand, the outer peripheral surface of the upper drum 118 is positively deformed and formed from a perfect circle. That is, regarding the cylindricity of the outer peripheral surface of the upper drum 118 and the outer peripheral surface of the lower drum 111, the central region PC of the outer peripheral surface of the upper drum 118 projects most, and then the T-side guide 107.
The region PT of the outer peripheral surface of the upper drum 118 corresponding to the side is large, and the upper drum 11 corresponding to the S side guide 106 side is large.
The area PS of the outer peripheral surface of 8 is smaller than the area PT of the outer peripheral surface.

Referring to FIG. FIG. 3 is a model view of the air film when the upper drum 118 is positively deformed as shown in FIG. FIG. 3 shows the relationship between the upper drum 118 and the rotary drum 114. Moreover, the air film A formed by the running of the tape 1 is shown.

In FIG. 3, the outer peripheral surface of the upper drum 118 (also referred to as the tape running surface) is the upper drum 1 shown in FIG.
18 is emphasized and shown compared with the outer peripheral surface.

The center of rotation R1 in FIG.
14 is the center of rotation. The rotary drum 114 is rotated in the RD direction. The magnetic tape 1 is run in the tape running direction. As a result, an air gap A is formed between the tape 1 and the rotary drum 114.

However, since the outer peripheral surface of the upper drum 118 is formed so as to project as shown by the regions PS, PC and PT as shown in FIG. 2, it is actually rotated with the tape 1 as shown in FIG. The distribution of the air film A formed between the rotating peripheral surface of the drum 114 and the vicinity of the magnetic head becomes uniform.

In this way, the shape of the tape running surface which is the outer peripheral surface of the upper drum 118 which is a fixed drum is previously
The optimum shape is selected and formed in accordance with the distribution gap of the air film A generated between the rotating peripheral surface of the rotating drum 114 and the running tape 1, so that the cylindricity can be adjusted conventionally. The step of inserting a spacer and adjusting the cylindricity of the upper drum and the lower drum can be omitted.

On the outer peripheral surface of the upper drum 118,
The part PU corresponding to the drum support 100 is a part of a perfect circle. As a result, the upper drum 118 and the lower drum 11
As shown in FIG. 1, when fixing the relative position of the drum 1 by the drum support 100, it can be easily fixed as in the conventional case.

Next, a drum manufacturing apparatus and a manufacturing method therefor for molding the shape of the outer peripheral surface of the upper drum 118 or the tape running surface as shown in FIGS. 2 and 3 will be described.

FIG. 4 shows a drum manufacturing apparatus. In FIG. 4, a byte 119 is set on the X slide 121 via the byte folder 120.

This X slide 121 is a Z axis slide 1.
23 is set to be movable in the Z direction. The X slide 121 can be moved in the X direction by the X axis servo motor 122. Further Z-axis slide 123
Can be moved in the Z direction via the Z-axis servo motor 124. The X axis and the Z axis are orthogonal to each other.

A rotary encoder 116 is set on the main shaft 115. The chuck 117 of the main shaft 115 is provided with the claw 11.
The upper drum 118 can be detachably fixed via the connector 8.

Next, a molding method, which is also called a method for manufacturing the upper drum 118 in such a drum manufacturing apparatus, will be described. The upper drum 118 is fixed to the main shaft 115 via a chuck 117 and a claw 118.

The rotation angle of the upper drum 118 at this time is obtained by the rotary encoder 116. The tape running surface of the upper drum 118 moves the X-axis slide 121 to stop the bite 119 at the set position.

Next, the rotary encoder 116 reads the rotation angle of the main shaft 115, the X-axis slide 121 is moved in the X-axis direction in synchronization with this rotation angle, and the Z-axis slide 12 is moved.
By moving 3 in the Z direction, the tape running surface of the upper drum 118 as shown in FIGS. 2 and 3 can be formed. With such a drum manufacturing apparatus, each region P constituting the outer peripheral surface of the upper drum 118 as shown in FIG.
Form S, PC, PT, PU.

Next, please refer to FIG. 5 to FIG. 5 to 7 show an embodiment of another method for manufacturing a drum of the present invention. In this embodiment, a region P as a convex portion of the shape of the tape running surface of the upper drum 118 as shown in FIG.
The thickness of the upper drum 118 is made thin according to S, PC, and PT.

FIG. 5 schematically shows the roughed upper drum 118. The outer diameter center C1 and the inner diameter center C2 of the upper drum 118 are displaced. Thereby, for example, the thin region TP
Etc. can be formed. Due to such a rough machining procedure, the regions PS, PC, PT shown in FIGS.
The upper drum 118 is thin-walled so as to correspond to PU and PU.

Next, FIG. 6 shows a finishing process of the upper drum 118. The machining center is the outer diameter center C1, and finishing is performed by the cutting tool 119. Due to the cutting resistance at that time, the thin portion TP is processed into a perfect circle while being pressed inward at the time of machining, but thereafter, the elastic deformation of the thin portion TP causes the thin portion TP to recover to the outside as shown in FIG. Has a convex shape.

By such a processing procedure, it is possible to form the protruding convex portion TPR as compared with the outer peripheral surface shape of the upper drum 118 shown in FIG. By applying this processing procedure, it is possible to form the protruding regions PS, PC and PT on the outer peripheral surface of the upper drum 118 as shown in FIG.

As described above, in the above-described embodiment, the outer peripheral surface (tape running surface) of the upper drum is manufactured to have a shape suitable for the required cylindricity of the upper drum and the lower drum, and the drum support and the lower drum are supported. The required high-precision cylindricity can be obtained simply by fastening it to the drum.

The present invention is not limited to the above embodiment. For example, instead of molding the upper drum into a deformed shape by cutting, the upper drum is molded with a molding material, and at that time, the shape of the mold is set to the required deformed shape of the upper drum. As a result, the required upper drum 118 as shown in FIGS. 2 and 3 can be obtained.

In this case, the shape of the outer peripheral surface of the upper drum 118 formed by the die is optimal in accordance with the distribution of the air film generated between the rotating peripheral surface of the rotary drum and the running tape. Shaped into a shape.

[0047]

As described above, according to the present invention, it is possible to obtain a required cylindricity by simply assembling the fixed drum and the rotating drum, and it is necessary to obtain a predetermined cylindricity in the conventional case. The adjustment process can be omitted, and the time can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a perspective view showing a preferred embodiment of a rotary magnetic head device of the present invention.

FIG. 2 is a diagram showing the shapes of an upper drum and a lower drum (cylindricity of the upper drum and the lower drum) in the rotary head drum device of FIG.

FIG. 3 is a plan view showing the deformed shape of the upper drum of FIG. 2 in an emphasized manner, showing the rotating drum together, and further showing a model of an air film.

FIG. 4 is a view showing a drum manufacturing apparatus for manufacturing the upper drum as shown in FIG.

FIG. 5 is a diagram showing an upper drum formed by rough processing.

FIG. 6 is a diagram showing a finishing process step following FIG. 5;

FIG. 7 is a view showing a state in which the outer peripheral surface of the upper drum is inflated and completed, following FIG. 6;

FIG. 8 is a perspective view showing a conventional rotary magnetic head device.

9 is a model view of an air film in the conventional rotary magnetic head device of FIG.

FIG. 10 is an exploded perspective view showing a rotary drum and a lower drum in a conventional rotary magnetic head device.

FIG. 11 is a perspective view showing a state in which the conventional rotary drum, the lower drum and the upper drum of FIG. 10 are assembled and the cylindricity adjusting spacer is inserted.

FIG. 12 is a model view of the air film in a state in which the upper drum is eccentrically attached to the rotating drum by inserting the spacer in FIG.

[Explanation of symbols]

100 drum support 106 S-side guide 107 T-side guide 111 lower drum (fixed drum) 114 rotating drum (medium drum) 118 upper drum (fixed drum) PS area on the outer peripheral surface of the upper drum corresponding to the S-side guide of the PC upper drum Area PT in the center of the outer peripheral surface PT Area corresponding to the T side guide on the outer peripheral surface of the upper drum PU Area of a perfect circle on the outer peripheral surface of the upper drum

Claims (4)

(57) [Claims] 1. The upper drum and the lower drum are supported by a drum support.
It is a fixed drum supported by the upper drum.
In a rotary magnetic head device that is a rotary drum that rotates between a drum and the lower drum , the tool is moved in a radial direction perpendicular to the main shaft and an axial direction of the main shaft in synchronization with rotation of the main shaft of the upper drum. Te, by forming the tape running surface of the upper drum, when viewed from the axial direction of the main shaft of the upper drum, the upper de
By the drum support on the ram and the lower drum
Form the supported part on the outer peripheral surface of a cylinder with a nearly circular cross section
And is not supported by the drum support
Note that the part of the drum is supported by the drum support.
As compared to the lower drum portion which is not present, the central region of the tape running surface of the upper drum overhangs most, then the tape outlet area of the tape running surface is large, and the tape inlet area of the tape running surface is large. Is smaller than the outlet region, corresponding to the uneven distribution of the air film generated between the rotating peripheral surface of the middle drum and the running tape, the tool is formed by the tool, Rotating magnetic head device. 2. The rotary magnetic head device according to claim 1, wherein the shape of the outer peripheral surface of the upper drum is formed so as to match the cylindricity of the upper drum and the lower drum. 3. The rotary magnetic head device according to claim 1, wherein the outer peripheral surface of the upper drum is formed by changing the wall thickness. 4. The rotary magnetic head device according to claim 2, wherein the outer peripheral surface of the upper drum is formed by molding.