JP2864662B2 - Rotating head device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary head device used for a so-called video recorder or digital audio tape recorder.

B. Summary of the Invention The present invention relates to a rotary head device having a support shaft fixedly supported and a sleeve member rotatably fitted to the support shaft, wherein a rotor magnet forming a motor is provided. The yoke and the yoke are attached to the sleeve member, and a thrust magnet that generates a magnetic force for urging the sleeve member in the axial direction of the support shaft is attached to the sleeve member, thereby reducing magnetic force loss between the rotor magnet and the yoke. At the same time, the thrust force can be adjusted without changing the driving torque of the motor.

C. Conventional technology Conventionally, a tape-shaped recording medium such as a video tape recorder or a digital audio tape recorder is used.
In a recording and / or reproducing apparatus configured to record and / or reproduce a high frequency information signal at a high density,
In order to perform a so-called helical scan on the recording medium by using a magnetic head, a rotary head device is used.

Such a rotary head device, as shown in FIG.
It has a fixed drum 102 fixedly disposed on a chassis 101 of a recording and / or reproducing apparatus constituted by using this rotary head device. The fixed drum 102 is formed in a substantially cylindrical shape using a material such as aluminum. A support shaft 103 is fixedly erected on the fixed drum 102 along the axis of the fixed drum 102.

A rotating drum support disk 105b is provided on the distal end side of the support shaft 103 via a fluid bearing 104.
The outer fitting is rotatably fitted around the shaft. The rotating drum support disk 105b is provided with the support shaft 10 along the axis.
A support hole 105c into which 3 is inserted is formed. The fluid bearing 104 is made of a liquid having an appropriate viscosity filled between the outer peripheral surface of the support shaft 103 and the inner surface of the support hole 105c. The liquid forming the fluid bearing 104 circulates 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 with respect to the support shaft 103. , The rotating drum support disk 105b
Is held at a position coaxial with the support shaft 103.

The rotating drum support disk 105b has a rotating drum 10
5a is mounted coaxially with the support shaft 103. This rotating drum 105a is
The fixed drum 102 is formed into a columnar shape having substantially the same outer diameter by the same material as that of the fixed drum 102.

A magnetic head 106 is mounted on a side of the rotating drum 105a facing the fixed drum 102. This magnetic head 106 has a front end side provided with a magnetic gap portion,
On the outer side of the peripheral surface of the rotating drum 105a,
It is projected by a predetermined amount of about 30 μm.

The rotating drum 105a includes the rotating drum 10
The rotation operation is performed by a motor 109 constituted by a rotor magnet 107 attached to 5a and a stator coil 108 attached to the fixed drum 102.

The rotor magnet 107 is formed in an annular shape, and is mounted on a side of the rotating drum support disk 105b facing the fixed drum 102. This rotor magnet 10
7 is coaxial with the support shaft 103. The rotor magnet 107 is magnetized such that a predetermined number of magnetic poles are polarized in the circumferential direction. The stator coil 108 is formed by a plurality of coils to form the rotor magnet 1.
It is formed in an annular shape of approximately the same size as 07. The stator coil 108 is mounted on the side of the fixed drum 102 facing the rotary drum 105a so as to be coaxial with the fixed drum 102, and
It is opposed to 7 with a predetermined minute gap. Thus, the rotor magnet 107 and the stator coil 108 constitute the motor 109 which is a so-called surface-facing motor.

In a recording and / or reproducing apparatus using the rotary head device configured as described above, a tape body serving as a recording medium is fed and tilted and wound around each of the drums 102 and 105a. 105a is the above motor
Rotated by 109. Then, the magnetic head 106
Performs a so-called helical scan by sliding the magnetic gap portion against the tape body in a direction inclined to the side edge of the tape body.

D. Problems to be Solved by the Invention By the way, in the rotating head device as described above,
The fixed drum 102 has a function of a yoke for guiding a magnetic flux generated from the rotor magnet 107. That is,
The motor 109 has 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 a fixed drum 102 cause magnetic loss. In the motor 109, this magnetic force loss causes
It has become difficult to improve the efficiency of converting power consumption into driving torque.

In particular, in order to reduce the size of the rotary head device, the motor 109 and the drums 102 and 105 are used together.
Is reduced in size, and it becomes more difficult to obtain a sufficient driving torque.

Further, in the rotary head device as described above, a thrust force for urging the rotary drum 105 in the axial direction of the support shaft 103 for positioning the rotary drum 105 in the axial direction of the support shaft 103, It is obtained by the magnetic force generated by the rotor magnet 107. Therefore, in this rotary head device, without changing the driving force of the motor 109,
The thrust force cannot be freely adjusted.

Therefore, the present invention has been proposed in view of the above-described circumstances, and a magnetic force loss in a motor is reduced, and a sufficient driving torque can be obtained even if the device configuration is downsized. It is an object of the present invention to provide a rotary head device capable of adjusting a thrust force for urging a sleeve member in an axial direction of a support shaft without changing a driving torque.

E. Means for Solving the Problems In order to solve the above problems and achieve the above objects, a rotary head device according to the present invention includes a support having a base end fixedly supported on a chassis via a support member. A shaft, a sleeve member rotatably fitted to the support shaft via a fluid bearing, a rotor magnet attached to the sleeve member, and a yoke attached to the sleeve member to face the rotor magnet. A stator coil disposed on the chassis and interposed between the rotor magnet and the yoke to constitute a motor together with the rotor magnet and the yoke; and a stator member mounted on the sleeve member and connecting the sleeve member to a base of the support shaft. A thrust magnet that generates a magnetic force biasing in the end side direction, wherein the sleeve member is provided by a tip end of the support shaft. Axial position of the support shaft is made is positioned.

F. Action In the rotary head device according to the present invention, a sleeve member rotatably fitted via a fluid bearing to a support shaft whose base end side is fixedly supported via a support member to a chassis is The motor is rotated by a motor including a rotor magnet and a yoke attached to the sleeve member and a stator coil fixed to the chassis. Further, the sleeve member is urged toward the base end side of the support shaft by a magnetic force generated by a thrust magnet attached to the sleeve member,
The axial position of the support shaft is determined by the tip of the support shaft.

G. Examples Hereinafter, specific examples of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a rotary head device according to the present invention has a recording and / or
Alternatively, a lower drum 2 and an upper drum 4 disposed at positions fixed to a chassis 1 of the reproducing apparatus, and a plurality of magnetic heads 29 and 30 rotatably supported between the lower drum 2 and the upper drum 4 are provided. It has a middle drum 28 to be attached.

In this rotary head device, a magnetic tape as a recording medium is wound around each of the drums 2, 4, and 28, the middle drum 28 is rotated, and the magnetic heads 29 and 30 are brought into sliding contact with the magnetic tape. Is a device for writing and / or reading information signals to and from the magnetic tape.

The lower drum 2 is formed in a substantially cylindrical shape using a material such as aluminum. The lower drum 2 is fixedly mounted on the chassis 1 by a plurality of lower drum mounting screws 6, 6 screwed in from the lower surface side of the chassis 1.

A stay mounting screw 7 is provided on the outer peripheral surface of the lower drum 2.
Thus, the lower end of the upper drum support stay 5 is attached. The upper drum support stay 5 is formed in a substantially rod shape,
It 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 an upper drum attaching screw 8. The upper drum 4 is made of a material such as aluminum.
The lower drum 2 is formed in a cylindrical shape having substantially the same diameter. The upper drum 4 has an outer peripheral surface portion formed by the upper drum support stay 5.
And is coaxial with the lower drum 2, and is supported by the lower drum 2 by forming a gap corresponding to the thickness of the middle drum 28. The support shaft 3 is attached to the upper drum 4 along the central axis. The support shaft 3 is supported so that the upper end side thereof is pressed into a support shaft insertion hole formed in the upper drum 4 along the center axis of the upper drum 4 and hangs down to the chassis 1 side. . The lower end of the support shaft 3 is formed through a center hole formed in the lower drum 2 along the axis of the lower drum 2 and a through hole formed in the chassis 1 corresponding to the center hole. It protrudes below the chassis 1.

The support shaft 3 has a sleeve member 9 formed in a cylindrical shape.
Are externally slidably and rotatably fitted. The sleeve member 9 is formed to be slightly longer than a portion of the support shaft 3 hanging down from the lower surface of the upper drum 4. A liquid having a predetermined viscosity is filled between the inner peripheral surface portion 9a of the sleeve member 9 and the outer peripheral surface portion of the support shaft 3, and a so-called fluid bearing is formed. That is, when the sleeve member 9 rotates with respect to the support shaft 3, the liquid forming the fluid bearing circulates between the inner peripheral surface portion 9a and the outer peripheral surface portion of the support shaft 3 to generate a dynamic pressure. The sleeve member 9 is supported so as to be coaxial with the support shaft 3.

On the outer peripheral side of the sleeve member 9, the middle drum 28 is externally fitted and attached so as to be interposed between the upper drum 4 and the lower drum 2.
The middle drum 28 is formed of a material such as aluminum into a disk shape having substantially the same diameter as the lower drum 2 and the upper drum 4. Also, in this middle drum 28, this middle drum
Along the central axis of 28, a central hole into which the sleeve member 9 is fitted is provided. A plurality of magnetic heads 29, 30 are mounted on the drum 28. These magnetic heads 29 and 30 are arranged such that the front end side where the magnetic gap portion is provided is located outside the outer peripheral surface of the middle drum 28 by 20 μm to 30 μm.
It is supported so as to protrude by a predetermined minute amount of about μm.

In addition, 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 second signals for transmitting and receiving information signals to and from the respective magnetic heads 29 and 30. Second rotary transformers 24 and 27 are provided.
The first rotary transformer 24 includes a primary coil 23 mounted in the lower drum 2 so as to face the middle drum 28, and a primary coil 23 mounted on the middle drum 28 so as to face the lower drum 2. And the secondary coil 22 provided. The second rotary transformer 27
A primary coil 25 mounted in the upper drum 4 so as to face the middle drum 28;
And a secondary coil 26 attached so as to face the upper drum 4.

The middle drum 28 is located at the lower end of the sleeve member 9, that is, at a position below the chassis 1.
A rotor magnet 12 and a yoke 13 constituting a motor for rotating the motor are mounted. That is, a substantially cylindrical yoke support member 10 is screwed and attached to the outer peripheral side of the lower end side of the sleeve member 9. On the outer peripheral side of the yoke support member 10, a magnet support plate 11 and
13 are installed. The magnet support plate 11 is formed of a so-called highly magnetically permeable material, and is attached near the lower end of the yoke support member 10 so as to form a flange. The yoke 13 is connected to the magnet support plate 11
The magnet support plate 11 is formed of the same material as
Is attached to the chassis 1 side from the magnet support plate 11 via a predetermined gap. The rotor magnet 12 is formed in an annular shape whose outer diameter is substantially equal to the outer diameter of the magnet support plate 11, and is coaxial with the sleeve member 9 on the side of the magnet support plate 11 facing the yoke 13. It is attached so that it becomes. The rotor magnet 12 is magnetized such that a predetermined number of magnetic poles are arranged in the circumferential direction. A so-called magnetic gap is provided between the rotor magnet 12 and the yoke 13.

A stator substrate 15 for supporting a stator coil 14 constituting the motor is mounted on the lower surface side of the chassis 1. The stator substrate 15 is attached to the chassis 1 with a predetermined gap formed by interposing a boss 16 with the substrate 1 and a substrate attaching screw 17. The stator coil 14 is mounted on the stator substrate 15 so as to be positioned and supported in a magnetic gap between the rotor magnet 12 and the yoke 13.

Thus, the motor is constituted by the rotor magnet 12, the yoke 13, and the stator coil 14. That is, when a predetermined drive current is supplied to the stator coil 14, the rotor magnet 12
The yoke 13 is driven to rotate.

An annular thrust magnet 18 is attached to the yoke 13 on the side facing the lower drum 2. The thrust magnet 18 is required to face the lower surface of the lower drum 2 through a through hole provided in the chassis 1. A thrust yoke 19 formed in a disk shape is attached to the lower surface of the lower drum 2 so as to face the thrust magnet 18.
The thrust yoke 19 has a through hole at the center so that it does not contact the sleeve member 9. The thrust yoke 19 is formed of a magnetic material.
Therefore, the thrust magnet 18 attracts the thrust yoke 19, thereby causing the sleeve member 9 to move.
To the upper drum 4 side. The attraction force of the thrust magnet 18 is a 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 performed by the yoke support member 1
The adjustment is performed using an adjustment bolt 21 which is screwed into the inner peripheral side of 0 from the lower end side. The adjusting bolt 21 has an upper end facing the lower end of the support shaft 3. A spherical member 20 is interposed between the adjusting bolt 21 and the support shaft 3. Therefore, the lower end of the support shaft 3 and the upper end of the adjusting bolt 21 hold the spherical member 20 by the thrust force. That is, the yoke support member
The axial position of the support shaft 3 with respect to the support shaft 3 of the sleeve portion 9 is determined by the screwing amount of the adjustment bolt 21 into the support shaft 3. Due to the adjustment bolt 21, the sleeve member 9 prevents the middle drum 28 from contacting either the upper drum 4 or the lower drum 2, and the gap between the coils in the rotary transformers 24, 27 is fixed. And the thrust magnet 18 and the thrust yoke 19 are positioned at a predetermined distance.

In the recording and / or reproducing apparatus configured by using the rotary head device according to the present invention configured as described above, when the recording and / or reproducing mode is set, the drums 2, 4, and 28 The magnetic tape is wound obliquely, the middle drum 28 is rotated at a predetermined speed by the motor, and the magnetic tape is fed. Then, the magnetic heads 29 and 30 are brought into sliding contact with the magnetic tape and perform a so-called helical scan. In order to guide the magnetic tape and feed the magnetic tape on a predetermined traveling path, a stepped lead 2a is provided on the outer peripheral surface of the lower drum 2. .

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

Further, in this rotary head device, the thrust force in the fluid bearing does not change the driving torque of the motor, but the distance between the thrust magnet 18 and the thrust yoke 19, or the magnetic force of the thrust magnet 18, By changing, it can be adjusted appropriately.

Further, in this rotary head device, since the motor is provided outside each of the drums 2, 4, and 28,
The fluid bearing span can be made longer than the outer diameter of each of the drums 2, 4, and 28, and the sleeve member 9 and the middle drum 28 can be tilted with respect to the support shaft 3 without causing inclination. It can be supported with high precision.

H. Effects of the Invention As described above, in the rotary head device according to the present invention, the rotary head is rotatably supported via the fluid bearing with respect to the support shaft whose base end is fixedly supported on the chassis via the support member. The fitted sleeve member is rotated by a motor constituted by a rotor magnet and a yoke attached to the sleeve member and a stator coil provided on the chassis.

Therefore, in the motor of this rotary head device, the rotor magnet and the yoke are integrally rotated, and the magnetic force loss between the rotor magnet and the yoke can be reduced, and the power consumption can be reduced satisfactorily. Can be converted to

In addition, the above-mentioned sleeve member, by the magnetic force generated by the thrust magnet attached to this sleeve member,
The support shaft is urged in the proximal direction, and the position of the support shaft in the axial direction is determined by the distal end of the support shaft.

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

That is, according to the present invention, the magnetic force loss in the motor is reduced, sufficient drive torque can be obtained even if the device configuration is reduced in size, and the sleeve member can be connected to the support shaft without changing the drive torque of the motor. An object of the present invention is to provide a rotary head device capable of adjusting a thrust force applied in an axial direction and capable of favorably positioning the sleeve member.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing the configuration of the rotary head device according to the present invention. FIG. 2 is a longitudinal sectional view showing a configuration of a conventional rotary head device. DESCRIPTION OF SYMBOLS 1 ... Chassis 2 ... Lower drum 3 ... Support shaft 4 ... Upper drum 5 ... Upper drum support member 9 ... Sleeve member 12 ... Rotor magnet 13 ... Yoke 14 ... Stator coil 18 ... Thrust magnet 19 ...... Thrust yoke 28 ...... Medium drum

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoichiro Senshu 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (56) References JP-A-63-145821 (JP, A) JP-A Sho JP-A-62-12147 (JP, A) JP-A-61-94215 (JP, A) JP-A-59-71103 (JP, A) JP-A-59-63024 (JP, A) A) JP-A-58-182127 (JP, A) JP-A-59-95428 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G11B 5/52

Claims (1)

(57) [Claims] 1. A support shaft fixedly supported on a base end side of a chassis via a support member, and a sleeve member rotatably fitted to the support shaft via a fluid bearing. A rotor magnet attached to the sleeve member; a yoke attached to the sleeve member so as to face the rotor magnet; and a yoke arranged 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 base end of the support shaft. A rotary head device in which the position of the support shaft in the axial direction is determined by the tip of the support shaft.