JPH1186246A - Rotary head apparatus, and manufacture of the rotary head apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain by one bearing an inexpensive apparatus convenient to assemble, by rotating an oil-containing metal bearing about a fixed shaft together with a rotary drum having a rotatable magnetic head pressed in an outer circumferential part of the rotatable oil-containing metal bearing inserted in the fixed shaft fixed to a fixed drum. SOLUTION: An oil-containing metal bearing 5 obtained by sintering a metal is constituted of a cylindrical part 5a, a flange part 5b at one end of the cylindrical part, supporting holes 5c at both ends and an escape hole 5d of a larger diameter than a diameter of the supporting holes 5c. The oil-containing metal bearing 5 is pressed and fitted in a central hole 6 of a rotary drum R having a magnetic head, and inserted to a fixed shaft 1 fixed to a fixed drum, thereby holding the fixed shaft 1 by the supporting holes 5c at both ends of a large distance. The oil-containing metal bearing 5 and the rotary drum R rotate centering the fixed shaft 1 without any rotation deflection. Accordingly, an apparatus compact in an axial direction can be obtained inexpensively with good productivity simply by pressing in one bearing once.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head device used for a video tape recorder or the like as a magnetic recording / reproducing device, and a method for manufacturing the rotary head device.

[0002]

2. Description of the Related Art As shown in FIG. 7, a rotary head device used in a conventional magnetic recording / reproducing apparatus includes a fixed drum K positioned below and a rotary drum R disposed above the fixed drum K. And a motor M arranged above the rotating drum R. The fixed drum K has a cylindrical fixed shaft 31 fixed at the center thereof and a concave portion 32 provided on a side facing the rotary drum R. The concave portion 32 accommodates a spring 33 and a brush 34. Have been. A magnetic head 35 is attached to a rotating drum R rotatable about the fixed shaft 31 by screws 36,
The height of the magnetic head 35 is adjusted by another screw 37 screwed into the rotating drum R.

The ball bearing 38 is provided on the inner race 3.
8a, outer ring 38b, inner ring 38a and outer ring 38b
And the two ball bearings 3 having such a configuration.
8 are provided with outer ring portions 38 on both sides of the center hole 39 of the rotating drum R.
b is attached to the rotating drum R by press-fitting. Further, by mounting ball bearings 38 on both sides of the center hole 39 of the rotating drum R, the distance between the bearings on the fixed shaft 31 is increased and the rotational vibration of the rotating drum R is reduced. The bearing 38 is assembled by holding the rotating drum R with a jig (not shown), press-fitting one ball bearing 38 from above one of the center holes 39, and then turning the rotating drum R upside down. Another ball bearing 38 from above the other
Is press-fitted and assembled. The ball bearing 38 thus assembled on the rotary drum R
Further, the inner ring portion 38a is press-fitted into the fixed shaft 31 and attached, so that the outer ring portion 38b and the rotary drum R rotate via the ball 38c.

When the ball bearing 38 is mounted on the fixed shaft 31 together with the rotary drum R, the brush 34 resiliently contacts the outer ring 38b of the ball bearing 38 so that static electricity and the like on the rotary drum R side are grounded. Has become. In addition, the rotary transformer 40 that supplies a video signal to the magnetic head 35 at the time of recording and takes out a reproduced signal at the time of reproduction includes a fixed transformer 40a and a rotary transformer 40b. The rotary transformer 40 is disposed between the fixed drum K and the rotary drum R while being located on the outer periphery of the ball bearing 38. The fixed transformer 40a is attached to the fixed drum K. Reference numeral 40b is attached to the rotary drum R, and the rotary transformer 40b rotates together with the rotary drum R.

The motor M comprises a stator 41 supported by a fixed shaft 31 and a rotor 42 mounted on a rotating drum R. And the stator 41
Fixed member 41a press-fitted and attached to fixed shaft 31
And a back yoke member 41c made of magnetic metal attached to the fixing member 41a by screws 41b, and a coil 41 attached to the back yoke member 41c.
and a core 41e made of a magnetic metal provided with d. The rotor 42 has a U-shaped cross section and a mounting plate 42 having a bottom plate 42a and a cylindrical portion 42b.
c and the bottom plate 42a of the mounting plate 42c
And a cylindrical magnet 42e attached to the cylindrical portion 42b by press fitting or the like. The core 41e is disposed in a cylindrical magnet 42e, and the core 41e and the magnet 42e face each other with the same clearance S over the entire circumference.

[0006] The conventional rotary head device as described above,
The rotating drum R is rotated by the motor M,
The magnetic head 35 is also rotated by the rotation of the rotary drum R, and the magnetic tape T moves while being pressed against and contacted with the magnetic head 35 by a predetermined pressing force P.
Alternatively, reproduction is performed.

[0007]

In the conventional rotary head device, since the ball bearing 38 is used for the bearing of the rotary drum R, the cost of the device is increased, and two ball bearings 38 are used. Therefore, there is a problem that the cost of the apparatus is further increased. In addition, since the ball bearing 38 includes the inner and outer ring portions 38a and 38b and the ball 38c, the ball bearing 38 becomes large in the radial direction, and there is a problem that the device becomes large. In addition, there is a problem that the rotary transformer 40 disposed on the outer periphery of the ball bearing 38 also becomes large, and further, the device becomes large, and the cost increases with the large size of the rotary transformer 40.

The two ball bearings 38 are incorporated into the rotating drum R by one ball bearing 38.
After having been mounted on the rotary drum R, the rotary drum R must be turned upside down and another ball bearing 38 must be mounted, which is problematic in that assembly is troublesome, productivity is low, and the cost is high. In addition, the inner diameter of the inner ring 38a of the ball bearing 38 varies greatly. Therefore, in order to eliminate the rotational fluctuation of the rotary drum R, it is necessary to prepare several types of fixed shafts 31 having different outer shapes and use them after matching them to the actual one. However, there is a problem that the cost increases.

[0009]

As a first means for solving the above problems, a fixed drum, a fixed shaft fixed to the fixed drum, and a rotatable oil-impregnated metal inserted into the fixed shaft are provided. Bearing, having a magnetic head, comprising a rotatable rotary drum pressed into the outer circumference of the oil-impregnated bearing, the oil-impregnated metal bearing together with the rotary drum,
The fixed shaft is configured to rotate around the fixed shaft. As a second solution, the oil-impregnated metal bearing includes a cylindrical portion having a support hole in contact with the fixed shaft at both end portions and a relief hole having a diameter larger than the support hole at an intermediate portion, The rotary drum was press-fitted into the outer circumference of the cylindrical portion facing the escape hole. As a third solution, the oil-impregnated metal bearing includes the cylindrical portion and a flange formed at one end of the cylindrical portion, and one end of the rotary drum is brought into contact with the flange. The configuration was adopted.

As a fourth solution, the fixed drum is provided at one end of the rotary drum, and a rotary transformer is provided between the rotary drum and the fixed drum. On the other end side of the rotating drum, a motor comprising a stator and a rotor attached to the rotating drum is arranged and configured, and the cylindrical portion of the oil-impregnated metal bearing is positioned on the rotating transformer side, The configuration is such that the flange of the oil-impregnated metal bearing is located on the motor side. As a fifth solution, the brush provided on the stator side of the motor is configured to directly contact the flange of the oil-impregnated metal bearing or to contact a metal spacer on the flange. As a sixth solution, the brush is constituted by a spring member made of a spring metal.

As a seventh solution, there is provided a rotating drum having a fixed drum, a fixed shaft fixed to the fixed drum, and a magnetic head, rotatably mounted on the fixed shaft via an oil-impregnated metal bearing. A drum, and a motor provided on one end side of the rotating drum, wherein a driving magnet of a rotor and a core of a stator are arranged so as to form a gap in a radial direction, and the rotor is opposed to the core. And a magnet that generates an attractive force in the axial direction of the fixed shaft. Further, as an eighth solution, a rotating drum having a fixed drum, a fixed shaft fixed to the fixed drum, and a magnetic head, and rotatably attached to the fixed shaft via an oil-impregnated metal bearing, A motor provided on one end side of the rotating drum, wherein a driving magnet of the rotor and a core of the stator are arranged so as to form a gap in the radial direction, and the axis of the rotor is set to the axis of the fixed shaft. In the aligned state, the rotor is mounted on the rotating drum, and the core disposed in the drive magnet of the rotor is mounted off-center with respect to the fixed shaft, and the magnetic force between the core and the drive magnet is adjusted. The configuration is such that the gap is small on the one hand and large on the other.

[0012] As a ninth solution, an oil-impregnated metal bearing having a cylindrical portion having a support hole in the center is formed by cutting an outer circumferential portion of the cylindrical portion with reference to the support hole. A method of manufacturing a rotary head device in which the outer circumference of the cylindrical portion is press-fitted into a rotary drum. As a tenth solution, an oil-impregnated metal bearing having a cylindrical portion having a support hole at the center is press-fitted into a rotary drum, and then the outer circumferential portion of the rotary drum is cut with reference to the support hole. And a method of manufacturing the rotating head device.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotary head device of the present invention and a method of manufacturing the rotary head device will be described with reference to FIGS. 1 to 6. FIG. 1 is a sectional view of the rotary head device of the present invention.
2 is an enlarged sectional view of a main part of the rotary head device of the present invention, FIG. 3 is an explanatory view for explaining a method of manufacturing the rotary head device of the present invention, and FIG. 4 is another embodiment of the rotary head device of the present invention. FIG. 5 is a perspective view of a spring member according to another embodiment of the rotary head device of the present invention, and FIG. 6 is an explanatory view showing another embodiment of the rotary head device of the present invention.

As shown in FIGS. 1 and 2, the rotary head device according to the present invention comprises a stationary drum K located below.
And a rotary drum R disposed above the fixed drum K.
And a motor M arranged above the rotary drum R. In the fixed drum K, a cylindrical fixed shaft 1 is fixed at the center thereof, and a magnetic head 2 is mounted on a rotating drum R rotatable about the fixed shaft 1 by screws 3, and the rotating drum R is rotated. The height of the magnetic head 2 is adjusted by another screw 4 screwed into the drum R.

The oil-impregnated metal bearing 5 formed by sintering a metal includes a cylindrical portion 5a, a flange portion 5b provided at one end of the cylindrical portion 5a, and a central portion of the cylindrical portion 5a.
The support hole 5c is provided at both ends of the support hole 5a and an escape hole 5d provided at an intermediate portion between the support holes 5c at both ends and having a diameter larger than that of the support hole 5c. The oil-impregnated metal bearing 5 is press-fitted into the center hole 6 of the rotary drum R, and is mounted.
Is inserted into the fixed shaft 1, and the fixed shaft 1 is
, And the oil-impregnated metal bearing 5 and the rotary drum R are rotatable on the fixed shaft 1 around the fixed shaft 1. Further, the connection between the oil-impregnated metal bearing 5 and the rotary drum R is performed by pressing the cylindrical portion 5a into the center hole 6 of the rotary drum R and pressing the flange portion 5b.
Is brought into contact with one end of the rotating drum R, and then,
The rotating drum R is in a state of being pressed into the outer circumferential portion of the cylindrical portion 5a facing the relief hole 5d. Further, by providing the support holes 5c at both ends of the oil-impregnated metal bearing 5, the interval between supports on the fixed shaft 1 is increased, and the rotational fluctuation of the rotary drum R is reduced.

As shown in FIG. 3, the method of manufacturing such a rotary head device includes an oil-impregnated metal bearing 5 having a cylindrical portion 5a, a flange portion 5b, a support hole 5c, and a relief hole 5d.
Is formed by sintering a metal. Thereafter, a pin Z as a jig is pressed into the support hole 5c to finish the surface of the support hole 5c, thereby forming the support hole 5c having a desired hole diameter. . Therefore, the hole diameter of the bearing can be easily formed to a predetermined amount, and the actual alignment with the fixed shaft 1 becomes unnecessary. Then, with the pin Z pressed into the support hole 5c, the cylindrical portion 5 is pressed.
The outer circumference of a is cut and finished. That is, the support hole 5
After the outer circumferential portion of the cylindrical portion 5a is cut with reference to c, the pin Z is removed, and then the oil-impregnated metal bearing 5 is removed.
Into the center hole 6 of the rotating drum R, the rotating drum R
The production of the oil-impregnated metal bearing 5 is completed. In general, the oil-impregnated metal bearing 5 has a large variation in the axis between the outer periphery and the hole. If two oil-impregnated metal bearings are used, the rotary drum R may be inclined with respect to the fixed shaft 1 or may be eccentric during rotation. There is a problem of doing. On the other hand, according to the manufacturing method of the present invention, the support hole 5 of the oil-impregnated metal bearing 5 is thus formed.
Since the outer circumferential portion is cut with reference to c, it is possible to make the outer circumference of the oil-impregnated metal bearing 5 coincide with the axis of the hole, so that the rotary drum R is mounted eccentrically with respect to the center of the fixed shaft 1. Can be prevented. As another manufacturing method, the oil-impregnated metal bearing 5 may be pressed into the rotary drum R, and thereafter, the outer periphery of the rotary drum R may be cut with reference to the support holes 5c.

The rotary transformer 7 which supplies a video signal to the magnetic head 2 at the time of recording and takes out a reproduced signal at the time of reproduction includes a fixed transformer 7a and a rotary transformer 7b. The rotary transformer 7 is disposed between the fixed drum K and the rotary drum R while being positioned on the outer periphery of the cylindrical portion 5a of the oil-impregnated metal bearing 5, and the fixed transformer 7a is attached to the fixed drum K. The rotary transformer 7b is attached to the rotary drum R, and the rotary transformer 7b rotates with the rotary drum R.

The motor M includes a stator 8 supported by the fixed shaft 1 and a rotor 9 mounted on the rotating drum R.
And the motor M includes a fixed drum K
Is disposed on the other end side of the rotary drum R on which the is disposed. The stator 8 of the motor M has a fixing member 8b attached to the fixed shaft 1 by screws 8a, a back yoke member 8c made of magnetic metal attached to the fixing member 8b, and an attachment to the back yoke member 8c. And a core 8e made of a magnetic metal provided with a coil 8d. Further, the rotor 9 of the motor M has a cup shape having a U-shaped cross section, a mounting plate 9c having a bottom plate portion 9a and a cylindrical portion 9b, and a screw for mounting the bottom plate portion 9a of the mounting plate 9c to the rotating drum R. 9d, and a magnet 9g having a cylindrical portion 9e and a plate-like bottom plate 9f extending inward from one end of the cylindrical portion 9e. And 9g of magnet
The cylindrical portion 9e is attached to the tubular portion 9b of the mounting plate 9c by bonding so that the bottom plate 9f is placed on the bottom plate portion 9a of the mounting plate 9c. The core 8 is attached to the cylindrical portion 9e.
The bottom plate 9f is magnetized so as to generate a magnetic attraction force in the axial direction of the fixed shaft 1 between the bottom plate 9f and the core 8e. ing. The core 8e is provided in a magnet 9g, and the core 8e is opposed to the cylindrical upper portion 9e and the bottom plate 9f of the magnet 9g with a predetermined clearance. When the rotating drum R is mounted on the fixed shaft 1, the bottom plate 9f of the magnet 9g is constantly drawn toward the core 8e,
The thrust load due to the weight of the rotating drum R applied to the rotating contact portion between the fixed drum K and the oil-impregnated metal bearing 5 is reduced.

A spring 10 and a columnar brush 11 are accommodated in the recess 8f of the fixing member 8b. A fixed shaft 1 is provided between the flange 5b of the oil-impregnated metal bearing 5 and the fixing member 8b. A spacer 12 made of an inserted metal is provided, and the brush 11 elastically contacts the spacer 12, so that static electricity or the like on the rotating drum R side is grounded. In the rotary head device of the present invention as described above, the rotary drum R is rotated by the motor M, and the rotation of the rotary drum R causes the magnetic head 2 to rotate. The magnetic tape T moves in a state where the magnetic tape T is pressed and contacted by the pressing force P to perform recording or reproduction.

In the above embodiment, the oil-impregnated metal bearing 5 is described as having the flange 5b. However, the oil-impregnated metal bearing 5 may not have the flange 5b, and the brush 11 may be elastically contacted with the spacer 12. As described above, the brush 11 may be directly in elastic contact with the flange 5b of the oil-impregnated metal bearing 5 without the spacer 12.

FIGS. 4 and 5 show another embodiment of the present invention, in which a brush is formed by a spring member 13 made of a springy metal instead of the spring 10 and the brush 11 in the above embodiment. It is. In the embodiment shown in FIG. 4, the spring member 13 is interposed between the flange portion 5b of the oil-impregnated metal bearing 5 and the fixing member 8b. Is also good. By the spring member 13, static electricity and the like on the rotating drum R side are grounded as in the above embodiment. Other configurations are the same as those of the above-described embodiment. Here, the same components are denoted by the same reference numerals, and description thereof is omitted.

FIG. 6 shows another embodiment of the present invention, in which the rotor 9 is mounted on the rotating drum R in a state where the axis of the rotor 9 is aligned with the axis G of the fixed shaft 1, and the driving magnet of the rotor 9 is driven. Core 8 disposed in a cylindrical portion 9e
e is displaced from the center of the axis G of the fixed shaft 1, and the magnetic gaps S1 and S2 between the core 8e and the drive magnet formed of the cylindrical portion 9e are small on one side (S1) and large on the other side (S2). ). The small magnetic gap S1 is formed by the magnetic gaps S1 and S2.
On the side, the core 8 always exerts a force for strongly pulling the cylindrical portion 9e in the direction of the axis G, and the rotating drum R rotates while maintaining this state. Thus, even if the gap between the support hole 5c of the oil-impregnated metal bearing 5 and the fixed shaft 1 is slightly large, the rotating drum R rotates without generating rotational bias due to the urging force in the direction of the axis G. The position where the small magnetic gap S1 is provided may be appropriately selected and provided for the magnetic tape T as a matter of course. The other configuration is the same as that of the above-described first or second embodiment. The same components are denoted by the same reference numerals, and description thereof is omitted here.

[0023]

Since the rotary head device of the present invention uses the oil-impregnated metal bearing 5, it is inexpensive, requires only one bearing, has good assemblability, and is inexpensive as compared with the conventional one. Device can be provided. Further, since the oil-impregnated metal bearing 5 is used, the size is reduced in the radial direction as compared with the related art, and a compact device can be provided. Further, the oil-impregnated metal bearing 5 is provided with a support hole 5c and a relief hole 5d, and presses the rotary drum R into the outer circumferential portion of the cylindrical portion 5a facing the relief hole 5d. It is possible to provide a device that can reduce the influence on the support hole 5c and can smoothly rotate the oil-impregnated metal bearing 5 with respect to the fixed shaft 1. Further, since the oil-impregnated metal bearing 5 is formed by providing the flange 5b at one end of the cylindrical section 5c, by pressing the oil-impregnated metal bearing 5 into the rotary drum R, the flange 5b is brought into contact with one end of the rotary drum R. The rotary drum R can be positioned with respect to the escape hole 5d, and an inexpensive device with good assemblability can be provided. Further, since the cylindrical portion 5a of the oil-impregnated metal bearing 5 is located on the rotary transformer 7 side and the flange portion 5b is located on the motor M side, the rotary transformer 7 can be arranged on the outer periphery of the cylindrical portion 5a in the radial direction. The rotary transformer 7 can be reduced in size, and the rotary transformer 7 can be reduced in cost, so that a small and inexpensive device can be provided. Further, since the brush 11 is provided on the stator 8 side of the motor M, the brush 11 is
Can be arranged, and a small device can be provided in the axial direction. Also,
By configuring the brush 11 with the spring member 13, it is possible to provide an inexpensive device with good assemblability.

Further, a bottom plate 9f, which is a magnet, is provided on a magnet 9g constituting the rotor 9, and the rotating drum R is always attracted to the core 8 by this magnet.
The thrust load applied to the oil-impregnated metal bearing 5 due to the weight of the rotating drum R can be reduced, and therefore, the thrust wear between the fixed drum K and the oil-impregnated metal bearing 5 can be reduced, thus providing a highly reliable device. it can. Also,
The rotor 9 is mounted on the rotating drum R in a state where the axis of the rotor 9 is aligned with the axis G of the fixed shaft 1, and a core 8 e arranged in a driving magnet (cylindrical portion 9 e) of the rotor 9 is attached to the axis of the fixed shaft 1. The magnetic gap S between the core 8e and the drive magnet composed of the cylindrical portion 9e is disposed at a position shifted from the center G.
1, S2 is small (S1) on the one hand and large (S2) on the other hand, so that the small magnetic gap S1
The core 8e always exerts a force for strongly pulling the cylindrical portion 9e in the direction of the axis G in the direction of the axis G, and the rotating drum R rotates while maintaining this state. It is possible to provide a device that can rotate without causing the rotation.

Further, the oil-impregnated metal bearing 5 is connected to the support hole 5c.
After cutting the outer circumference of the cylindrical portion 5a based on
Since the rotary drum R is press-fitted into the cylindrical portion 5a, the coaxiality of the axis of the cylindrical portion 5a of the contained metal bearing 5 and the axis of the support hole 5c can be matched, so that the press-fitted rotary drum R is fixed. A device that can be mounted without being eccentric with respect to the shaft 1 and that is free from rotational shake can be provided. Further, as compared with the conventional one using two ball bearings 38, the oil-impregnated metal bearing 5 can be incorporated into the rotating drum R by a single press-fitting, so that it is possible to provide a device with good productivity and low cost. . After the oil-impregnated metal bearing 5 is press-fitted into the rotary drum R, the outer circumferential portion of the rotary drum R is cut with reference to the support hole 5c. And the axis of the fixed shaft 1 can be aligned with each other, so that a device with less rotation blur can be provided.

[Brief description of the drawings]

FIG. 1 is a sectional view of a rotary head device according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of the rotary head device of the present invention.

FIG. 3 is an explanatory diagram for explaining a method of manufacturing a rotary head device according to the present invention.

FIG. 4 is a sectional view showing another embodiment of the rotary head device of the present invention.

FIG. 5 is a perspective view of a spring member according to another embodiment of the rotary head device of the present invention.

FIG. 6 is an explanatory view showing another embodiment of the rotary head device of the present invention.

FIG. 7 is a sectional view of a conventional rotary head device.

[Explanation of symbols]

 K Fixed drum R Rotary drum M Motor Z Pin P Pressing force T Magnetic tape S1, S2 Magnetic gap G Shaft 1 Fixed shaft 2 Magnetic head 3, 4 Screw 5 Oil-bearing metal bearing 5a Cylindrical part 5b Flange part 5c Support hole 5d Escape hole Reference Signs List 6 center hole 7 rotating transformer 7a fixed transformer 7b rotating transformer 8 stator 8a screw 8b fixing member 8c back yoke member 8d coil 8e core 8f recess 9 rotor 9a bottom plate 9b cylindrical portion 9c mounting plate 9d screw 9e cylindrical portion Bottom plate 9g Magnet 10 Spring 11 Brush 12 Spacer 13 Spring member

Claims (10)

[Claims] An oil-impregnated metal bearing having a fixed drum, a fixed shaft fixed to the fixed drum, a rotatable oil-impregnated metal bearing inserted into the fixed shaft, and a magnetic head. A rotatable rotary drum press-fitted therein, wherein the oil-impregnated metal bearing rotates together with the rotary drum on the fixed shaft around the fixed shaft. 2. The oil-impregnated metal bearing has a support hole in contact with the fixed shaft at both ends and a cylindrical portion having a relief hole having a larger diameter than the support hole at an intermediate portion, and is opposed to the relief hole. 2. The rotary drum is press-fitted into an outer peripheral portion of the cylindrical portion.
The rotating head device according to claim 1. 3. The oil-impregnated metal bearing includes the cylindrical portion and a flange formed at one end of the cylindrical portion, and one end of the rotary drum is brought into contact with the flange. The rotary head device according to claim 2, wherein 4. A fixed drum is provided at one end of the rotary drum, and a rotary transformer is provided between the rotary drum and the fixed drum. Side, a motor composed of a stator and a rotor attached to the rotary drum is arranged and configured, the cylindrical portion of the oil-impregnated metal bearing is positioned on the rotary transformer side, and the oil-impregnated metal is positioned on the motor side. The rotary head device according to claim 3, wherein the flange portion of the bearing is located. 5. The motor according to claim 4, wherein a brush provided on a stator side of the motor is brought into direct contact with the flange of the oil-impregnated metal bearing or with a metal spacer on the flange. Rotary head device. 6. The rotary head device according to claim 5, wherein the brush is formed of a spring member made of a springy metal. 7. A rotary drum having a fixed drum, a fixed shaft fixed to the fixed drum, and a magnetic head, rotatably mounted on the fixed shaft via an oil-impregnated metal bearing, and a rotating drum. A motor provided on one end side, wherein a driving magnet of a rotor and a core of a stator are arranged so as to form a gap in a radial direction, and the rotor is disposed so as to face the core, and the fixed A rotary head device provided with a magnet that generates an attractive force in an axial direction of a shaft. 8. A rotating drum having a fixed drum, a fixed shaft fixed to the fixed drum, and a magnetic head, rotatably mounted on the fixed shaft via an oil-impregnated metal bearing, A motor provided on one end side, wherein a driving magnet of the rotor and a core of the stator are arranged so as to form a gap in the radial direction, wherein the axis of the rotor is aligned with the axis of the fixed shaft. Mounting the rotor on the rotating drum, mounting the core disposed in the drive magnet of the rotor off-center with respect to the fixed shaft, wherein the magnetic gap between the core and the drive magnet is one A rotary head device characterized in that it is small and large on the other hand. 9. An oil-impregnated metal bearing having a cylindrical portion having a support hole in the center thereof is formed by cutting an outer circumferential portion of the cylindrical portion with reference to the support hole, and then cutting the outer circumferential portion of the cylindrical portion. A method for manufacturing a rotary head device, wherein a part is press-fitted into a rotary drum. 10. An oil-impregnated metal bearing having a cylindrical portion having a support hole in the center is press-fitted into a rotary drum, and then the outer circumferential portion of the rotary drum is cut with reference to the support hole. Manufacturing method of a rotary head device.