JPH0426910A - Rotary head device - Google Patents

Abstract

PURPOSE:To adjust thrust force without changing the driving torque of a motor by fitting a rotor magnet constituting the motor and a yoke to a sleeve and fitting a thrust magnet to this sleeve member. CONSTITUTION:A sleeve member 9 is externally inserted through a fluid bearing to a support shaft 3, which base end side is fixedly supported through a supporting member 5 to a chassis 1, so as to be rotated, and this sleeve member 9 is rotationally operated by the motor composed of a rotor magnet 12 which provided in the sleeve member 9, yoke 13 and stator coil 14 fixedly arranged to the chassis 1. On the other hand, the sleeve member 9 is energized in the base end side direction of the support shaft 3 by magnetic force to be generated by a thrust magnet 18 fitted to this sleeve member 9, and the axial position of the support shaft 3 is positioned by the tip part of the support shaft 3. Thus, the thrust force can be adjusted without changing the driving torque of the motor.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a rotary head device used in so-called video tape recorders, digital audio recorders, and the like.

B1 Summary of the Invention The present invention provides a rotating head device comprising a fixedly supported support shaft and a sleeve member rotatably fitted onto the support shaft, in which a rotor magnet and a yoke constituting a motor are provided. and a thrust magnet that generates a magnetic force that urges the sleeve member in the axial direction of the spindle, thereby reducing magnetic force loss between the rotor magnet and the yoke. , the thrust force can be adjusted without changing the drive torque of the motor.

C1 Prior Art Conventionally, recording and/or recording devices configured to record and/or reproduce high-frequency information signals at high density on tape-shaped recording media, such as video tape recorders and digital audio tape recorders, have been used. Alternatively, in a reproducing apparatus, a rotary head device is used to cause a magnetic head to perform so-called helical scanning on the recording medium.

As shown in FIG. 2, such a rotary head device has a fixed drum 102 fixedly disposed on a chassis 101 of a recording and/or reproducing device configured using this rotary head device. It becomes.

The fixed drum 102 is made of a material such as aluminum and has a substantially cylindrical shape. This fixed drum 102
Along the axis of this fixed drum 102,
A support shaft 103 is fixedly planted.

A fluid bearing 10 is provided on the tip side of the support shaft 103.
4, a rotary drum support disk 105b is externally fitted around the support shaft 103 so as to be rotatable around the axis. A support hole 105c into which the support shaft 103 is inserted is bored along the axis of the rotary drum support disk 105b.

The fluid bearing 104 is made of a liquid having an appropriate viscosity that is filled between the outer peripheral surface of the support shaft 103 and the inner surface of the support hole 105c. When the rotary drum support disk 105b is rotated relative to the support shaft 103, the liquid forming the fluid bearing 104 is transferred to the support shaft 103.
The rotary drum support disk 105b is rotated between the outer circumferential surface of the support hole 105c and the inner surface of the support hole 105c.
Hold it in a position coaxial with 3.

A rotary drum 105a is attached to the rotary drum support disk 105b so as to be coaxial with the support shaft 103. The rotating drum 105a is formed of the same material 4 as the fixed drum 102 and has a cylindrical shape with an outer diameter between the fixed drum 102 and the groove.

A magnetic head 106 is attached to the side of the rotating drum 105a facing the fixed drum 102. The magnetic head 106 has a distal end side provided with a magnetic gap portion protruding outward from the circumferential surface of the rotating drum 105a by a predetermined amount of about 20 am to 30 μm.

The rotating drum 105a is
05a and the stator coil 108 attached to the fixed drum 102.
Rotation operation is performed by a motor 109 composed of.

The rotor magnet) 107 is formed in an annular shape, and is attached to the fixed drum 1 of the rotating drum support disk 105b.
It is attached to the side opposite to 02. This rotor magnet 107 is coaxial with the support shaft 103. This rotor magnet 7) 107 is magnetized so that a predetermined number of magnetic poles are polarized in the circumferential direction. The stator coil 108 is formed of a plurality of coils into an annular shape with a size equal to the distance between the rotor magnet 107 and the rotor magnet 107. This stator coil 10B is attached to the side of the stationary drum 102 opposite to the rotating drum 1.5a so as to be coaxial with the stationary drum 102, and has a predetermined minute position relative to the rotor magnet 107. They face each other with a gap. In this way, the rotor magnet 107 and the stator coil 108
This constitutes the motor 109, which is a so-called surface facing motor.

In a recording and/or reproducing apparatus using a rotary head device configured in this manner, a tape body serving as a recording medium is fed, and each of the drums 102, 105a
The rotating drum 105a is rotated by the motor 109. Then, the magnetic head 106 brings the magnetic gap portion into sliding contact with the tape body in a direction inclined to the side edge of the tape body, thereby performing a so-called helical scan.

D0 Problems to be Solved by the Invention Incidentally, in the above-described rotary head device, the fixed drum 102 has the function of a yoke that guides the magnetic flux generated from the rotor magnet 107. That is, the motor 109 is configured to have a yoke fixed to the chassis 101. Therefore, when the motor 109 is driven to rotate, the rotor magnet 107 and the fixed drum 102 serving as a yoke are rotated with respect to each other, and magnetic force loss occurs between the rotor magnet 107 and the fixed drum 102. . In the motor 109, this magnetic force loss makes it difficult to improve the efficiency of converting power consumption into driving torque.

In particular, when attempting to downsize the device configuration of this rotary head device, the motor 109 is downsized together with the drums 102 and 105, making it even more difficult to obtain sufficient driving torque.

Furthermore, in the above-described rotary head device, a thrust force for urging the rotary drum 105 in the axial direction of the support shaft 103 for positioning the support shaft 103 of the rotary drum 105 in the axial direction is applied to The above rotor magnet 10
It is obtained by the magnetic force generated by 7. Therefore, in this rotary head device, the thrust force cannot be freely adjusted without changing the driving force of the motor 109.

Therefore, the present invention is proposed in view of the above-mentioned circumstances, and it is possible to reduce the magnetic force loss in the motor, obtain sufficient driving torque even if the device configuration is downsized, and make it possible to reduce the magnetic force loss in the motor. It is an object of the present invention to provide a rotary head device that can adjust the thrust force that urges a sleeve member in the axial direction of a support shaft without changing the drive torque.

E1 Means for Solving the Problems In order to solve the above-mentioned problems and achieve the above-mentioned objects, the rotating head device according to the present invention includes a support shaft that is fixedly supported on the base end side with respect to the chassis via a support member. a sleeve member rotatably fitted onto the support shaft via a fluid bearing; a rotor magnet attached to the sleeve member; a yoke attached to the sleeve member facing the rotor magnet; A stator coil is disposed on the chassis and is interposed between the rotor magnet and the yoke to constitute a motor together with the rotor magnet and the yoke; The sleeve member is provided with a thrust magnet that generates a magnetic force that urges the shaft in the lateral direction, and the sleeve member is positioned in the axial direction of the shaft by the tip of the shaft.

F1 action In the rotary gutter device according to the present invention, a sleeve member is rotatably fitted externally via a fluid bearing to a support shaft that is fixedly supported on the proximal end side with respect to the chassis via a support member. is rotated by a motor constituted by a rotor magnet and yoke attached to the sleeve member, and a stator coil fixedly disposed with respect to the chassis. Further, the sleeve member is biased toward the proximal end of the support shaft by a magnetic force generated by a thrust magnet attached to the sleeve member, and the tip of the support shaft is used to position the support shaft in the axial direction. is positioned.

G. Examples Specific examples of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the rotating head device according to the present invention has the following features:
A lower drum 2 and an upper drum 4 are arranged at fixed positions with respect to a chassis 1 of a recording and/or reproducing apparatus configured using this rotary head device, and between these lower drum 2 and upper drum 4, A plurality of rotatably supported magnetic heads 2
9.30 is attached to the middle drum 2B.

In this rotary head device, a magnetic tape serving as a recording medium is wound around each of the drums 2 and 4° 28, and the middle drum 2
8 is a device which is rotated to bring the magnetic heads 29 and 30 into sliding contact with the magnetic tape to write and/or read information signals to and from the magnetic tape.

The lower drum 2 is made of a material such as aluminum and has a substantially cylindrical shape. The lower drum 2 is fixedly attached to the chassis 1 by a plurality of lower drum mounting screws 6.6 which are screwed into the lower surface of the chassis 1.

The lower end side of the upper drum support stay 5 is attached to the outer circumferential surface of the lower drum 2 by screws 7 for attaching the stay. The upper drum support stay 5 is formed into a substantially rod shape and is supported by the lower drum 2 so as to be perpendicular to the chassis 1 .

The upper drum 4 is attached to the upper end side of the upper drum support stay 5 by screws 8 for attaching the upper drum.

The upper drum 4 is made of a material such as aluminum and is formed into a cylindrical shape having approximately the same diameter as the lower drum 2. The upper drum 4 has its outer peripheral surface attached to the upper drum support stay 5 and is coaxial with the lower drum 2, and forms a gap corresponding to the thickness of the middle drum 28 with respect to the upper drum 2. It is supported by A support shaft 3 is attached to the upper drum 4 along the central axis. The upper end of the support shaft 3 is press-fitted into a support shaft insertion hole formed in the upper drum 4 along the central axis of the upper drum 4, and is supported so as to hang down toward the chassis 1. .

The lower end side of the support shaft 3 is connected to the lower drum 2 through a center hole formed in the lower drum 2 along the axis of the lower drum 20 and a through hole formed in the chassis 1 corresponding to the center hole. It protrudes further downward than the chassis 1.

A sleeve member 9 formed in a cylindrical shape is fitted onto the support shaft 3 so as to be slidable and rotatable. This sleeve member 9 is formed to be slightly longer than the portion of the support shaft 3 that hangs down from the lower surface of the upper drum 4. A liquid having a predetermined viscosity is filled between the inner circumferential surface portion 9a of the sleeve member 9 and the outer circumferential surface portion of the support shaft 3, forming a so-called fluid bearing. That is, the support shaft 3
In contrast, when the sleeve member 9 rotates, the liquid forming the fluid bearing circulates between the inner circumferential surface portion 9a and the outer circumferential surface portion of the support shaft 3, generating dynamic pressure, causing the sleeve member 9 to rotate. It is supported so as to be coaxial with the support shaft 3.

And, on the outer peripheral side of the sleeve member 9, it is interposed between the upper drum 4 and the lower drum 2,
The middle drum 28 is mounted externally. The middle drum 28 is made of a material such as aluminum and is formed into a disc shape having approximately the same diameter as the lower drum 2 and the upper drum 4.

Further, the middle drum 28 is provided with a center hole along the central axis of the middle drum 28, into which the sleeve member 9 is fitted. A plurality of magnetic heads 29, 30 are attached to this middle drum 28. These magnetic heads 29 and 30 have a distal end side provided with a magnetic gap section,
20 Bm on the outer side of the outer peripheral surface of the middle drum 28.
It is supported so as to protrude by a predetermined minute amount of about 30 μm.

Note that between the lower drum 2 and the middle drum 28 and between the upper drum 4 and the middle drum 28, there are first and A second rotary transformer 24.27 is provided. The first rotary transformer 24 includes a primary coil 23 installed in the lower drum 2 so as to face the middle drum 28, and a primary coil 23 installed in the middle drum 28 so as to face the lower drum 2. The secondary coil 22 is composed of a secondary coil 22. Further, the second rotary transformer 27 includes a primary coil 25 installed in the upper drum 4 so as to face the middle drum 28, and a primary coil 25 installed in the middle drum 28 so as to face the middle drum 4. A secondary coil 26 is attached to the secondary coil 26.

The middle drum 28 is located on the lower end side of the sleeve member 9, that is, on the lower side of the chassis 1.
A rotor magnet 12 and a yoke 13, which constitute a motor for rotating the rotor, are attached. That is,
A yoke support member 10 formed in a substantially cylindrical shape is screwed and attached to the outer peripheral side of the lower end of the sleeve member 9.

A magnet support plate 11 and a yoke 13 each having a disk shape are attached to the outer peripheral side of the yoke support member 10. The magnet support plate 11 is made of a so-called high magnetic permeability material, and is attached near the lower end of the yoke support member 10 so as to form a flange. The yoke 13 is formed of the same material as the magnet support plate 11, and is attached to the chassis 1 side with respect to the magnet support plate 11 with a predetermined gap therebetween.

The rotor magnet 12 is formed in an annular shape with an outer diameter approximately equal to the outer diameter of the magnet support plate 11,
The magnetic screw support plate 1 is attached to the side opposite the yoke 13 so as to be coaxial with the sleeve member 9. This rotor magnet 12 is magnetized so that a predetermined number of magnetic poles are arranged in the circumferential direction. A so-called magnetic gap is formed between the rotor magnet 12 and the yoke 13.

A stator base 115 for supporting the stator coil 14 constituting the motor is attached to the lower surface side of the chassis l. This stator board 15 is
The board is attached to the chassis 1 with screws 17, with a predetermined gap formed through a boss 16.

The stator coil 14 is attached to the stator substrate 15 so that it is positioned and supported within the magnetic gap between the rotor magnet 12 and the yoke 13.

In this way, the rotor magnet 12, the yoke 13, and the stator coil 14 constitute the motor. That is, by supplying a predetermined drive current to the stator coil 14, the rotor magnet 12 and the yoke 13 are rotationally driven.

Incidentally, a thrust magnet 18 formed in an annular shape is attached to the side of the yoke 13 facing the lower drum 2. The thrust magnet 18 is inserted into the lower drum 2 through a through hole provided in the chassis 1.
It should be viewed from the bottom of the screen. A disk-shaped thrust yoke 19 is attached to the lower surface of the lower drum 2 so as to face the thrust magnet 18 . This thrust yoke 19 has a through hole in the center and is configured not to come into contact with the sleeve member 9. This thrust yoke 19 is made of a magnetic material. Therefore, the thrust magnet 18
By attracting the thrust yoke 19, the sleeve member 9 is urged toward the upper drum 4 side.

The attraction force generated by the thrust magnet 18 becomes the so-called thrust force in the fluid bearing.

In this rotary head device, the positioning of the sleeve member 9, that is, the positioning of the middle drum 28 with respect to the upper and lower drums 2.4, is an adjustment that is screwed into the inner peripheral side of the yoke support member lO from the lower end side. bolt 21
The upper end of the adjustment bolt 21 is opposed to the lower end of the support shaft 3. A spherical member 20 is interposed between the adjustment bolt 21 and the support shaft 3. Therefore, the lower ends of the support shafts 3 and the upper ends of the adjustment bolts 21 sandwich the spherical member 20 by the thrust force. That is, the axial position of the support shaft 3 of the sleeve member 9 relative to the support shaft 3 is determined by the amount of screwing of the adjustment bolt 21 into the yoke support member 10. The sleeve member 9 is configured such that the middle drum 28 does not come into contact with either the upper drum 4 or the lower drum 2 by the adjustment bolt 21, and the gap between each coil in each rotary transformer 2427 is maintained at a predetermined distance. Further, the thrust magnet 18 and the thrust yoke 19 are positioned at a predetermined distance from each other.

In the recording and/or reproducing device configured using the rotary hesode device according to the present invention configured as described above,
When the recording and/or reproducing mode is set, the magnetic tape is wound around each of the drums 2, 4.28 at an angle,
The middle drum 28 is rotated by the motor at a predetermined speed, and the magnetic tape is fed. Then, each of the magnetic heads 29 and 30 comes into sliding contact with the magnetic tape and performs a so-called helical scan. A step-shaped lid 2a is provided on the outer peripheral surface of the lower drum 2 in order to guide the magnetic tape so that the magnetic tape is fed along a predetermined running path. .

In this rotary head device, since the rotor magnet 12 and the yoke 13 are rotated at the same speed, there is little magnetic loss between the rotor magnet 12 and the yoke 13, and the drive current supplied to the stator coil 14 is small. can be converted into rotational driving torque with high efficiency.

Furthermore, in this rotary head device, the thrust force in the fluid bearing is controlled by the distance between the thrust magnet J8 and the thrust yoke 19, or the magnetic force of the thrust magnet 18, without changing the driving torque of the motor. By changing it, it can be adjusted as appropriate.

Furthermore, in this rotary head device, since the motor is provided on the outer side of each of the drums 2, 4.28, the fluid bearing The span can be increased, and the sleeve member 9 and the middle drum 28 can be supported with high precision without being tilted with respect to the support shaft 3.

H1 Effects of the Invention As described above, in the rotary hemostatic device according to the present invention, the support shaft is fixedly supported on the proximal end side with respect to the chassis via the support member, and is rotatable via the fluid bearing. The externally fitted sleeve member is rotated by a motor comprising a rotor magnet and a yoke attached to the sleeve member, and a stator coil disposed on the chassis.

Therefore, in the motor of this rotating head device,
The rotor magnet and the yoke are rotated integrally, so that magnetic loss between the rotor magnet and the yoke can be reduced, and power consumption can be favorably converted into driving torque.

Further, the sleeve member is biased toward the proximal end of the support shaft by a magnetic force generated by a thrust magnet attached to the sleeve member, and the tip of the support shaft is used to position the support shaft in the axial direction. is positioned.

Therefore, in this rotary head device, the thrust force can be freely adjusted without changing the drive torque of the motor.

That is, according to the present invention, magnetic loss in the motor is reduced, sufficient driving torque can be obtained even when the device configuration is downsized, and the sleeve member can be moved around the support shaft without changing the driving torque of the motor. It is possible to provide a rotational positioning device that can adjust the thrust force applied in the axial direction and can satisfactorily position the sleeve member.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the configuration of a rotary head device according to the present invention. FIG. 2 is a longitudinal sectional view showing the configuration of a conventional rotary head device.

Claims (1)

[Scope of Claims] A support shaft whose proximal end side is fixedly supported with respect to the chassis via a support member, and a sleeve member rotatably fitted onto the support shaft via a fluid bearing. a rotor magnet attached to the sleeve member; a yoke attached to the sleeve member facing the rotor magnet; a yoke disposed on the chassis and interposed between the rotor magnet and the yoke; A stator coil that constitutes a motor together with the rotor magnet and the yoke, and a thrust magnet that is attached to the sleeve member and generates a magnetic force that urges the sleeve member toward the proximal end of the support shaft, the sleeve member A rotary head device in which the axial position of the support shaft is determined by the tip of the support shaft.