JPH01204211A - Revolving head device - Google Patents

Abstract

PURPOSE:To obtain a stable non-contact bearing force of high centripetalism by providing a bearing to generate magnetic repulsion as the bearing means of a revolving part. CONSTITUTION:An annular single magnetic pole magnet 16 is provided on the lower surface of a yoke 17 in the lower surface of a fixed piece 14 and a same magnet 15 is provided with facing to the magnet 16 in a yoke 18 of the upper surface of a revolving disk 3 as well. Then, the facing magnetic pole surfaces of the magnets are the same magnetism. A same magnet 20 is provided in a yoke 21 in the bottom part of a lower side cylinder 4 and a same magnet 19 of single magnetism is provided with facing to the magnet 20 in a yoke 22 between a thrust dynamic pressure bearing surface 26 and the fitting part of a rotator yoke 11 as well. Then, the facing magnetic pole surfaces of the magnets are same magnetism. Thus, since the rotating part is borne by the magnetic repulsion, a stable non-contact bearing of the high centripetalism can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rotary head device such as a video tape recorder (hereinafter referred to as a VTR), and particularly to a means for supporting a rotary part.

[Conventional technology]

Conventionally, in VTR rotating head devices, it has been common to use contact type bearings such as ball bearings as support means for the rotating parts including the head, but in order to reduce rotational unevenness and lateral vibration vibration, , one using a hydrodynamic bearing has been proposed.

As an example, the rotating head device described in Japanese Patent Publication No. 61-3006 has (1) an outer rotor structure in which the motor is provided with a rotor coaxially outside a stator to which a coil is attached, and (2) a bearing. (3) A planar rotating transformer is used for signal transmission between the rotating part and the fixed part, (4)
The structure is such that the lower cylinder is fixed and the upper cylinder is rotated, and (5) a housing is provided at the bottom of the lower cylinder and a motor is fixed to this.

[Problem to be solved by the invention]

However, in a rotary head device using such a hydrodynamic bearing, there are the following points to be improved.

(In order to support the 11 rotating parts, a large supporting force is required, and for this reason, the fluid bearing must be made large, and the rotating head device becomes large.

(2) The bearing force of a hydrodynamic bearing is influenced by the viscosity of the fluid, the width of the gap into which the fluid is injected, etc., and it is difficult to obtain the desired bearing force with high precision.

If the error in this bearing force is large, especially in the case of a bearing force in the journal direction, an error will occur in head height adjustment, making it impossible to obtain highly accurate centering.

(3) In the case of a hydrodynamic bearing, the rotating part floats relative to the fixed part in a rotating state, but is in contact with the fixed part in a stationary state. For this reason, when the rotating part starts rotating, the rotating side of the hydrodynamic bearing comes into contact with the stationary side and rotates, which wears out the hydrodynamic bearing and shortens its life.

(4) In order to obtain a large bearing force, the dynamic pressure of the fluid must be increased, but for this purpose, a fluid with high viscosity must be used. However, if the viscosity of the fluid is high, the motor This will increase the load on the motor, and the uneven rotation of the motor will increase accordingly.In order to prevent this, it is possible to lower the viscosity of the fluid, but if this is done, the supporting force obtained will be small. (Therefore, in order to obtain a sufficiently large bearing force, the hydrodynamic bearing must be made large.

(5) At startup, the rotating part contacts the fixed part and rotates, which generates large vibrations and noise. Also, while the rotating part is rotating, the rotating side of the hydrodynamic bearing rotates in contact with the fluid, and the fluid also rotates under the influence of the rotating side while contacting the stationary side, resulting in vibration and noise. .

(6) Properties such as fluid viscosity change depending on temperature.

This makes it difficult to obtain stable bearing force.

In particular, the higher the viscosity of the fluid, the greater its temperature dependence.

In particular, high-definition VTR and digital VTR, which have been attracting attention in recent years,
Cylinder motors such as TRs require higher speeds, and for this reason, improvements to the above-mentioned problems are increasingly desired.

An object of the present invention is to improve the above points and provide a rotary head device which is suitable for practical use and has high performance.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a bearing that generates magnetic repulsion as a means for supporting a rotating part.

[Effect]

The rotating part floats relative to the fixed part due to the magnetic repulsion force generated by the bearing. A magnet or a short-circuit coil can be used as this bearing, and a magnet or a magnet and a short-circuit coil are provided facing the rotating part and the fixed part, respectively, and a repulsive force is generated between these magnets or between the magnet and the short-circuit coil. . The rotating part is supported in a non-contact manner, and is also supported in a non-contact manner when stopped. The magnetic repulsion force can be sufficiently large, so that the bearing can be made compact and a sufficient bearing force can be obtained to support the rotating part.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing a first embodiment of a rotary head device according to the present invention, in which 1 is a central axis, 2 is an upper cylinder, 3 is a rotating disk, 4 is a lower cylinder, and 5 is a fixed disk. Base, 5' is a head fixing base, 6 is a magnetic head, 7 is a rotating sleeve body, 8 is a rotor magnet, 9 is a circumferential stator coil, 10.11 is a rotor yoke, 12 is a substrate,
13 is a shield ring, 14 is a fixed piece, 15.16 is a magnet, 17.18 is a yoke, 19.20 is a magnet, 21.22 is a yoke, 23 is a fixed core of a rotating transformer, 24 is a rotating core of a rotating transformer, 25 is a thrust bearing piece, 26 is a thrust dynamic pressure bearing surface, 27.28 is a journal dynamic pressure bearing surface, 29 is a lubricating fluid, 30 is a lid, 31 is a substrate holder, 32 is a substrate, 33 is a brush, and 34 is a groove. , 35
~39 are boards, 40~48 are electronic components, 49.50 are connectors, 51~54 are lead wires, 55~71 are screws, 7
2 is a connector.

In the figure, the central shaft 1 has its lower end connected to the lower cylinder 4.
The fixing piece 14 is fitted into the upper end of the fixing piece 14 and fixed with a screw 67. This fixed piece 1
The upper cylinder 2 is attached to 4, and the screws 57 and 58
Fixed by Therefore, in this embodiment, the upper cylinder 2 and the lower cylinder 4 are fixed. These have the same outer diameter, and a gap is provided between the lower surface of the upper cylinder 2 and the upper surface of the lower cylinder 4.

A rotating sleeve body 7 made of, for example, brass is provided on the central axis between the fixed piece 14 and the bottom of the lower cylinder 4 with a slight clearance. Between the thrust bearing piece 2
5 is fixedly provided on the central shaft 1. The rotating sleeve body 7 consists of two concentric cylindrical parts, the inner cylindrical part is attached to the central axis l as described above, and the disk fixing base 5 is attached to the outer cylindrical part.
A fixed core 23 and a rotating core 24 of a cylindrical rotary transformer are arranged concentrically with the central axis 1 between these cylindrical parts. The fixed core 23 is attached to the lower part of the fixed piece 14, and the rotating core 25 is attached to the inner surface of the outer cylindrical portion of the rotating sleeve body 7.

The rotating disk 3 is fixed to the upper surface of the disk fixing base 5 by screws 59, and the head fixing base 5' on which the magnetic head 6 is mounted is attached to the outer peripheral side of the lower surface of this rotating disk together with the board 39 by screws 64. . Also, the tip of this head fixing base 5' has a screw 70.
The magnetic head 6 can be displaced in the vertical direction, thereby making it possible to adjust the height of the magnetic head 6. The outer peripheries of the rotating disk 3 and the head fixing base 5' are positioned in the gap between the upper cylinder 2 and the lower cylinder 4, and the magnetic head 6 slightly protrudes from this gap.

A rotor yoke 10 is fixed to the lower surface of the disk fixing base 5 with screws 61 and 71, and a rotor yoke 11 is fixed to the lower surface of the outer peripheral side of the fixed sleeve body 7. A rotor magnet 8 is attached to the lower surface of the rotor yoke 10, and the rotor magnet 8 and the rotor yoke 1
1, a substrate 12 carrying stator coils 9 is arranged, which are attached to the lower cylinder 4 by screws 62, 63. These rotor yoke 10°1
1. The rotor magnet 8 and the rotor coil 9 constitute a motor, and the disk fixing base 5 and the rotating sleeve body 7 also serve as part of the magnetic path of this motor. Further, a shield ring 13 is also provided on the inner surface of the lower cylinder 4 in order to prevent leakage of the magnetic flux of the motor. A drive current is supplied to the stator coil 9 of the motor via the connector 72.

On the upper surface of the upper cylinder 2, a board 35 on which electronic parts 40, 41 are mounted, and a board 36 on which electronic parts 42 are mounted are provided.
0 and a lead wire 51. In addition, screws 55, 56, etc. are installed on the top surface of the rotating disk 3.
Boards 37 and 38 are installed at different levels, and board 3
7 has electronic components 43 to 45, and the board 38 has electronic components 4.
6 to 48 are installed respectively. Here, the electronic component 48
is a head signal regeneration amplifier circuit, electronic component 47 is a control circuit such as a head changeover switch, electronic component 44 is a switching control signal processing circuit, and electronic component 45 is a circuit input forming circuit for forming a desired level of voltage from input power. , electronic parts 4
0 is a switching control signal generation circuit, electronic components 43 and 46 are electronic circuits required for these circuits, electronic component 42 is a head signal reproducing amplifier, and electronic component 41 is a head signal recording amplifier. Substrate 3 provided on the lower surface of head fixing base 5'
9 is provided with wiring connected to the coil of the magnetic head 6, and this wiring and wiring on the substrate 38 are connected by lead wires 53.

Connection pins or the like are used to connect the wiring on the substrates 37 and 38. Wiring connections between the substrates 37 and 38 and the substrate 36 are made via a rotary transformer consisting of a rotating core 24 and a fixed core 23 and lead wires.

Further, as will be described later, a substrate holder 31 that holds a substrate (not shown) provided with an annular slip ring is attached to the lower end surface of the fixed piece 14, and opposite to this, a substrate holder 31 is attached.
A base plate 32 provided with a brush 33 is attached to the upper end of the inner cylindrical portion of the rotating sleeve body 7. Electric power is supplied from the outside to each of the electric components 43 to 48 mounted on the substrates 37 and 38 on the rotating disk 3 through the slip ring, the brush 33, and the lead wire 54.

The circuit input forming circuit 45 processes this supplied power,
A voltage of a predetermined level is generated to be supplied to each circuit. For example, when the magnetic head 6 is attached to a piece of piezoelectric material to perform tracking control or the like, electric power is also required to drive the displacement of this piece of piezoelectric material. This circuit input forming circuit 4
5. Note that the voltage to be supplied to each circuit, the driving voltage for the piezoelectric material piece, etc. can be formed externally and supplied to each circuit via the brush 33, and in this case, the circuit input forming circuit 45 is not necessary.

Now, in this configuration, the gap between the central shaft 1 and the inner surface of the inner cylindrical part of the rotating sleeve body 7 is filled with lubricating fluid, and the inner cylindrical part and the central shaft 1 are connected to the rotating part (rotating part). It constitutes a liquid bearing for supporting the journal load of the sleeve body 7, the disk fixed base 5, the rotating disk 3, the IF air head 6, etc.). Here, the inner surface of the inner cylindrical portion of the rotating sleeve body 7 (journal dynamic pressure bearing surface) 2
7.28 is provided with journal groups 27a and 28a for generating journal dynamic pressure, as shown in FIG. 2(a).

Further, a thrust dynamic pressure bearing surface 26 is formed on the inner peripheral side of the lower surface of the rotating sleeve body 7, facing the upper surface of the thrust bearing pieces 25 with a minute gap therebetween. A lubricating fluid is filled between the thrust dynamic pressure bearing surface 26 and the thrust dynamic pressure bearing surface 26 to constitute a thrust load bearing fluid bearing.

Here, the thrust dynamic pressure bearing surface 26 is provided with a thrust group 26a for generating thrust dynamic pressure, as shown in FIG. 2(b).

A recess is provided in the upper part of the fixing piece 14, in which lubricating fluid 29 is stored, and this recess is enclosed by a lid 30. A groove 34 is provided on the inner surface of the fixed piece 14 from a recessed portion along the central axis 1.
From the recess through the journal dynamic pressure bearing surface 27.28
Lubricating fluid is supplied between the thrust bearing piece 25 and the thrust dynamic pressure bearing surface 26.

A yoke 17 is provided on the lower surface of the fixed piece 14 , and a ring-shaped single-pole magnet 16 is attached to the lower surface of the yoke 17 .
is attached coaxially to the Further, a yoke 18 is also provided on the upper surface of the rotating disk 3, and this yoke 18 also includes:
An annular unipolar magnet 15 is provided to face the magnet 16. These magnets 15.1
The opposing magnetic pole surfaces of No. 6 have the same polarity, and a magnetic repulsive force is generated between them. The magnets 15 and 16 are configured so that this magnetic repulsive force consists of a thrust load bearing force and a journal load bearing force that push down the rotating part.

Additionally, a thrust support piece 25 is provided at the bottom of the lower cylinder 4.
A yoke 21 is provided on the outside of the yoke 21 , and an annular single-pole magnet 20 is provided coaxially with the central axis 1 . A yoke 22 is also provided between the thrust dynamic pressure bearing surface 26 on the lower surface of the rotating sleeve body 7 and the attachment part of the rotor yoke 11,
An annular unipolar magnet 19 is also attached to the lower surface of the magnet 20 so as to face the magnet 20 . The opposing magnetic pole faces of these magnets 19 and 20 have the same polarity, and a magnetic repulsion is generated between them. The magnets 19.2
0 is configured.

Next, the operation of this embodiment will be explained.

Even when the motor is stopped, the journal dynamic pressure bearing surfaces 27 and 28 of the rotating sleeve body 7 do not come into contact with the center shaft 1, and the thrust dynamic pressure bearing surface 26 of the rotating sleeve body 7 and the thrust bearing piece 25 do not come into contact with each other. The magnets 15.16.degree. and 19.20.degree. are magnetized so as to generate such strong thrust load order support force and journal load order support force.

When a drive current is supplied to the stator coil 9 of the motor via the connector 72, the motor is started and the rotating part rotates. The bearings at this time include the magnetic repulsion generating portions of the magnets 15, 16 and 19, 20, the fluid bearings of the central shaft 1, the journal dynamic pressure bearing surface 27, 28, the thrust bearing piece 25, and the thrust dynamic pressure bearing surface 26. It consists of

That is, the combined force of the own weight of the rotating part and the downward thrust load bearing force by the magnets 15.16, the upward thrust load bearing force by the magnets 19.20, and the upward force by the thrust piece 25 and the thrust dynamic pressure bearing surface 26. The rotating part is thrust supported by the balance with the thrust load bearing force. In addition, the journal load bearing force by the magnets 15 and 16 and the journal load bearing force by the magnets 19 and 20 give a centripetal force to the rotating part, and this, the centrifugal force of the rotating part, the center axis 1 and the journal dynamic pressure bearing surface 27°28 balance with the journal load bearing force.

In this state, the magnetic head 6 is properly centered and rotates concentrically with the central axis 1. A magnetic tape (not shown) runs in spiral contact with the outer peripheral surfaces of the upper cylinder 2 and lower cylinder 4 over a predetermined angular range, and the magnetic head 6 scans this magnetic tape obliquely.

In the recording mode, the head signal is transmitted to the recording amplifier 41.
After being amplified, the signal is supplied to the magnetic head 6 via the fixed core 23 of the rotating transformer, the rotating core 24, the wiring on the substrate 38, the lead wire 53, and the like. In the reproduction mode, the head signal reproduced by the magnetic head 6 is supplied to the reproduction amplifier 48 for each head on the substrate 38 via the lead wire 53, and after being amplified, the head signal is sent to the reproduction amplifier 48 for each head in the control circuit 47. A continuous head signal is created by switching. This head signal passes through the rotating core 24 and fixed core 23 of the rotating transformer,
The signal is amplified by a regenerative amplifier 42 on the substrate 35. Note that the tack pulse generated by means not shown in the drawings is applied to the substrate 3.
The switching control signal is supplied to the switching control signal generation circuit 40 on the top of the circuit 5 to generate a switching control signal. This switching control signal passes through the fixed core 23 and rotating core 24 of the rotary transformer, is processed by the switching signal processing circuit 44 on the board 37, and is then supplied to the control circuit 47 on the board 38 to control the head switching switch. .

Next, a specific example of the magnetic repulsion generating section in FIG. 1 will be explained using a section consisting of magnets 19 and 20 as an example.

FIG. 3 is a cross-sectional view showing the first specific example.
Parts corresponding to the figures are given the same reference numerals.

In the figure, the annular magnet 19 has a -like wall thickness, and the magnetic pole surface facing the annular magnet 20 is parallel to the rotating surface. The outer diameter of the magnet 20 is larger than that of the magnet 19, and the outer circumference is thicker than the inner circumference. That is, the magnetic pole surface of the magnet 20 that faces the magnet 19 is inclined toward the inner peripheral side (in the direction of the central axis 1). Since the opposing magnetic pole faces of the magnets 19 and 20 have the same polarity, a magnetic repulsion force F0 is generated between them, but this magnetic repulsion force F0 is tilted in the direction of the central axis everywhere.

That is, this magnetic repulsion force F0 has a component (hereinafter referred to as a radial component) Fl that is parallel to the rotational surface and is directed toward the central axis 1.
and the component in the direction perpendicular to this (hereinafter referred to as the axial component)
Consists of F2. This radial component F1 becomes a journal load bearing force and applies a centripetal force to the rotating part. Further, the axial component F2 becomes the thrust load bearing force.

FIGS. 4(a) and 4(b) are cross-sectional views showing a second specific example of the magnetic repulsion generating section, in which 73 and 74 are polarization yokes, 75 are grooves, and correspond to FIG. 1. The parts are given the same symbols.

In the figure, the annular magnets 19 and 20 have a negative wall thickness, and an annular polarization yoke 73 having the same width as the annular magnet 19 is provided on the magnet 19. Further, the width of the magnet 20 is made wider than the width of the magnet 19, and the magnet 20 is provided with an annular polarization yoke 74 that is wider than this. An annular groove 75 is provided on the surface of the polarization yoke 74, and the polarization yoke 74 is provided in the groove 75.
3 are fitted with a slight gap.

The surfaces of the polarizing yokes 73 and 74 are connected to the magnets 19, respectively.
．． 20 so that they have the same polarity, and a magnetic repulsion force is generated between the polarization yokes 73 and 74 in the groove portion 75. This magnetic repulsive force is generated not only at the bottom of the groove 75 but also at the wall surface, and therefore a radial component F and an axial component F2 are generated. In this case, the radial component Fr consists of a component in the central axis direction and a component in the opposite direction.

As the polarization yokes 73 and 74, a magnetic material such as iron that is easy to process and can achieve high processing accuracy can be used. Therefore, in this specific example, the magnets 19 and 20
Even if the shape is simple and the dimensional accuracy is relatively low, by appropriately selecting the machining accuracy of the polarization yokes 73 and 74,
A predetermined bearing capacity can be easily secured.

FIGS. 5(a) and 5(b) show a third specific example of the magnetic repulsion generating section, in which 76 is a groove, and parts corresponding to those in FIG. 4 are given the same reference numerals. .

This specific example is as shown in FIGS. 5(a) and 5(b).
An annular groove 76 is further provided on the bottom surface of the groove portion 75. This groove 76 increases the amount of magnetic flux on both sides of the groove 76, increases the radial repulsive force, and further improves the stability of the journal load bearing compared to the specific example shown in FIG.

Furthermore, in the fourth specific example shown in FIG.
The bottom is tapered, and this also provides the same effect as the specific example shown in FIG.

FIG. 7 is a cross-sectional view showing a fifth specific example of the magnetic repulsion generating section, and parts corresponding to those in FIG. 4 are given the same reference numerals.

In this specific example, as shown in the figure, the annular polarizing yoke 73 provided on the magnet 19 is thicker on the inner circumferential side than the outer circumferential side, and the annular polarizing yoke 73 provided on the magnet 20 is thicker on the inner circumferential side than on the outer circumferential side. 74 is thicker on the outer circumferential side than on the inner circumferential side. In other words, the surface of the polarization yoke 74 is inclined in the central axis direction, and the surface of the polarization yoke 73 is
It is inclined parallel to the surface of 4.

With this configuration, a magnetic repulsion force F0 inclined in the direction of the central axis 1 is generated everywhere between the polarizing yokes 73 and 74, and as explained in the specific example of FIG. 3, the thrust load bearing force and the journal load bearing force are generated. occurs.

FIG. 8 is a sectional view showing a sixth specific example of the magnetic repulsion generating section, and parts corresponding to those in FIG. 7 are given the same reference numerals.

In this specific example, as shown in the figure, the polarization yoke 73 is thicker at the center than the outer and inner circumferences, and its surface is tapered. In comparison, the outer circumference and inner circumference are thicker. In other words, the surfaces of the polarization yoke 73 are concave, and these surfaces are arranged close to each other.

According to this configuration, between the polarization yokes 73 and 74,
A magnetic repulsion force inclined in one direction of the center axis is generated on the outer circumference side of the center, and a magnetic repulsion force inclined in the opposite direction is generated on the inner circumference side of the center, and these magnetic repulsion forces generate thrust load bearing force and journal. Load bearing capacity can be obtained.

FIG. 9 shows a seventh specific example of the magnetic repulsion generating section, in which (a) is a cross-sectional view and FIG. are given the same sign.

In the same figures (a) and (b), an annular magnet 19
On the other hand, the annular magnet 20 is wide and magnetized so that the opposing magnetic pole surfaces have the same polarity.

As is clear from FIG. 9(b), the magnetic pole surface of the magnet 20 has an annular non-magnetized area 77 in the center, and magnetized areas 77a, 77 on both sides of this non-magnetized area 77.
b.

Therefore, a magnetic repulsion force FOI tilted in the direction of the central axis 1 is generated between the magnetized %n SJ region 77b and the magnet 19, and a magnetic repulsion force F tilted in the opposite direction is generated between the magnetized region 77a and the magnet 19. . 2 occurs. These magnetic repulsive forces F O
1+ F ax provides a thrust load bearing force and a journal load bearing force such that the floating position of the magnet 19 is at the lowest potential position.

FIG. 10 is a sectional view showing an eighth specific example of the magnetic repulsion generating section.

In this example, as shown, yokes 73 and 74 are provided for each of the magnets 19 and 20 of the example shown in FIG. 9, respectively. As the yokes 73 and 74, a magnetic material such as iron or a non-magnetic material such as aluminum or brass, which is easy to process and can be processed with high precision, can be used.

The operation of this embodiment is similar to that of the embodiment shown in FIG. 9, but since the surfaces of the yokes 73, 74 can be machined with high precision, these surfaces can be brought sufficiently close together. Furthermore, when the yokes 73 and 74 are made of magnetic material, by appropriately selecting their surface shapes, the magnetic field distribution can be set according to the purpose.

FIG. 11 shows a ninth specific example of the magnetic repulsion generating section, in which (a) is a sectional view and ('b) is a plan view. Also, 19', 20', 20a'.

2Qb' and 20C' are magnets, 77' is a non-magnetized region, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the figure, the magnet 19' attached to the yoke 22 has an annular shape, and the annular region at the center of its surface is a non-magnetized region 77'. Further, on the annular yoke 21, a plurality of magnets 21' (here,
FIG. 11 (As shown in bl, three magnets 21a
', 21b', 21c') are magnets 19
These magnets 21' are provided at equal intervals along the non-magnetized regions 77' of the magnets 21'.

The opposing surfaces of 19' are magnetized to have the same magnetic pole.

With this configuration, a magnetic repulsive force is generated between the magnetized portion of the magnet 19' and each magnet 21', and the thrust load bearing force and journal Load bearing capacity can be obtained.

According to this example, magnet 21a'.

21b' and 21C' can be easily produced at low cost.

FIG. 12 is a sectional view showing a tenth specific example of the magnetic repulsion generating section, in which reference numeral 78 denotes a magnet, and parts corresponding to those in the previous drawings are given the same reference numerals.

In this specific example, as shown in the figure, a planar annular magnet 78 is further provided between the planar annular rotating side magnet 19 and the stationary side magnet 20. This magnet 78 is rotatably attached to the central shaft 1, and the opposing magnetic pole faces of the magnet 19.78, the magnet 78.
The 20 opposing magnetic pole surfaces are magnetized so that they each become the same magnetic pole. Further, the outer diameter of the magnet 78 is larger than the magnet 19.20, and the inner diameter of the magnet 78 is smaller than the magnet 19.20.

With this configuration, magnetic repulsion is generated between the magnets 19.78 and 20.78, respectively, and a thrust load bearing force and a journal load bearing force are obtained.

In the eleventh anomaly of the magnetic repulsion generating section shown in FIG. 13,
Magnet 19°20.78 in the specific example shown in Figure 12
A yoke 79°80.81.8 is attached to each opposing magnetic pole surface.
2, and the operation of this specific example is similar to that of the specific example shown in FIG.

In this specific example, materials that are easy to process and have high surface accuracy can be used for the yokes 79 to 82, and therefore the surface shape can be selected appropriately, so that the desired magnetic field distribution can be obtained and the specified bearing In addition, lubricating fluid is filled between the yoke 79°81 and the yoke 82 and 80, and a group for generating fluid dynamic pressure is provided on either of these surfaces to support the thrust load. It can also be used as a hydrodynamic bearing.

In addition, in the specific example of FIGS. 12 and 13, FIGS. 9 and 1
As in the specific example shown in FIG. 0, a non-magnetized region may be provided in the annular central portion of the magnet 78.

In this way, in the specific examples shown in FIGS. 12 and 13,
Since multiple gaps are provided between the magnets and magnetic repulsion is generated in each gap, non-contact bearing can be reliably achieved even when these gaps are small, and therefore a large bearing force can be obtained and high performance can be achieved. Highly stable support for the stewardess is possible.

The magnetic repulsion generating section described above is arranged at the lower part of the lower cylinder 4 of the rotary head device shown in FIG. 1, but among these, the configurations shown in FIGS. The magnetic repulsive force generating section is the magnet 15 in FIG.
．． It can also be applied to the magnetic repulsion generating section shown by 16.

Next, a specific example of a magnetic repulsion generating section provided in the motor will be described.

Figure 14 shows an example of this one-shot body, with the angle of 83°84
．． 85 is magnet, 8a~8h and 8a/~8h
' is a magnetic pole, 8' is a rotor magnet, and 10' is a rotor yoke, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the same figure (a), the rotor yoke 10 of the motor includes:
An annular magnet 8 is located on the inner circumferential side of the rotor magnet 8.
3 is provided coaxially with the central axis 1, and the substrate 12 includes:
An annular magnet 85 is provided opposite the magnet 83. Further, the rotor yoke 1 with respect to the substrate 12
A rotor yoke 10' is provided on the opposite side from the rotor yoke 10', a rotor magnet 8' is provided on the outer circumferential side of the rotor yoke 10', and an annular magnet 84 is provided on the inner circumferential side thereof coaxially with the central axis 1. This magnet 84 faces the magnet 85.

The magnets 83 and 84 are wider than the magnet 85, and the outer diameter r1 of the magnets 83 and 84 is larger than the outer diameter r2 of the magnet 85. In addition, the opposing magnetic pole surfaces of the magnets 83 and 85, the magnet 85
．． The opposing magnetic pole surfaces of 84 are magnetized so that they have the same magnetic pole. The mutual relationship between magnets 83 and 84 and magnet 85 is similar to that of magnet 2 in FIGS. 9 and 10.
This is almost the same as the mutual relationship between 0 and magnet 19.

The rotor magnet 8, as shown in FIG. 14(b),
Magnetic poles 8a to 8h are arranged so that their polarities are alternately different, and a magnet 83 magnetized into a single pole is arranged on the inner circumference of the rotor magnet 8. Furthermore, as shown in FIG. 14(C), the rotor magnet 8' is also
Magnetic poles 8a' to 8h' are arranged so that their polarities are alternately different, and a single-pole magnet 84 is arranged on the inner circumference of the rotor magnet 8'. These rotor magnets 8, 8' are arranged with the stator coil 9 in between, so that the magnetic poles of different polarities face each other, as shown in FIG. 14(a).

With this configuration, the motor rotates due to the action of the stator coil 9 and each magnetic pole of the rotor magnets io and 10', and magnetic repulsion is generated between the magnets 85 and 83, 84, so that the motor rotates in the thrust direction. Supporting force in the journal direction can be obtained.

Therefore, according to this specific example, the motor also has the function of rotary contact support, and in FIG.
The magnetic repulsion generating section shown in 19.20 is not required, and the magnetic leakage of the magnetic repulsion generating section can be significantly reduced due to the shielding effect of the keyer.

The specific example shown in FIG. 15 differs from the specific example shown in FIG. .7
7' is provided.

In addition, 77a, 77b, 77a', 77b
' is the magnetized region.

According to this configuration, also in this specific example, FIGS.
As in the specific example shown in FIG. 11, the thrust load bearing force and the journal load bearing force can be obtained at the same time due to the magnetic repulsion caused by the magnets 85 and 83, 84, which is even more effective than the specific example shown in FIG. Stable support of rotating parts is possible.

In the specific examples shown in FIGS. 14 and 15, the magnet 85 is not limited to an annular magnet, but may include a plurality of magnets arranged annularly and at equal intervals, as in the specific example shown in FIG. It may be something that has been done.

FIG. 16 is a configuration diagram showing a specific example of the power supply transmission section in FIG. are given the same sign.

In the figure, a substrate holder 31 provided on the lower end surface of the fixed piece 14 is attached to the central shaft 1 with a screw 88,
The group +Ji 86 held by this substrate holder 31 has 2
two annular slip rings 87a;

87b is provided concentrically with respect to the central axis 1. These slip rings 87a, 87b are connected to wiring on the substrate 36 (FIG. 1) via lead wires 52.

On the other hand, two brushes 33a and 33b are provided on the base plate 32 attached to the upper end surface of the inner cylindrical portion of the rotating sleeve body 7, and the brush 33a contacts the slip ring 87a, and the brush 33b contacts the slip ring 87b, respectively. ing. These brushes 33a, 33b are connected to wiring on a substrate 38 (FIG. 1) via lead wires 54.

In recording, playback mode, etc., as the rotating sleeve body 7 rotates, the brush 33a slides on the slip ring 87a, and the brush 33b slides on the slip ring 87b, thereby transmitting power and various control signals from the fixed part to the rotating part. It will be done.

In this specific example, the brushes 87a and 87b are provided on the flat substrate 86, but as shown in FIG.
6 may have a cylindrical shape, and brushes 87a and 87b may be provided thereon.

The first embodiment of the present invention has been explained above, but in this embodiment, (1) the thrust load and journal load of the rotating part are supported using magnetic repulsion, so the bearing The wear and friction of the parts can be significantly reduced. In other words, since the fluid dynamic pressure value can be reduced by the amount of support by magnetic repulsion, the viscosity of the lubricating fluid can be reduced in the fluid dynamic pressure section, and even in a stationary state before startup, the rotating part can be levitated by magnetic repulsion. You can keep it in a non-contact state. For low viscosity fluids,
Furthermore, since the amount of change in viscosity with respect to temperature is small, the floating support characteristics can be stabilized. By reducing friction, the power consumption of the drive motor can also be reduced, and rotational unevenness can also be reduced. Further, the life of the device, especially the bearing portion, can be greatly extended and the reliability can be improved. Furthermore, since the load on the motor can be reduced, vibration and noise of the entire device can also be reduced.

(2) Since the structure is capable of generating a journal bearing force at the same time as a thrust bearing force as a magnetic repulsion force, a stable magnetic bearing force can be obtained with a simple configuration.

(3) Since fluid dynamic pressure bearings are used in both the thrust and journal bearings, the bearing rigidity and damping force in the non-contact type bearing can be increased, and stable bearing performance with excellent resistance to external disturbances can be obtained.

(4) Since a head signal processing circuit such as an amplifier is provided in the rotating section, recording and reproduction signals can be amplified at a position extremely close to the magnetic head 6. Therefore, the capacitance of the lead wire portion can be significantly reduced, and a wide band head signal can be transmitted with low loss and high S/N. Furthermore, since head signals can be switched within the rotating section, the number of channels within the rotating transformer can be reduced, making it more compact, and crosstalk between channel coils can also be reduced. therefore,
It is also possible to make the entire device smaller and more compact.

(5) Since two substrates are used in the rotating section, the wiring space for circuits such as signal processing circuits, electronic components, etc. can be increased, and a multi-head structure can be easily accommodated. As shown in Figure 1, multiple board mounting structures include the use of multiple single-sided wiring boards, one or more double-sided wiring boards, or the use of single-sided wiring and double-sided wiring boards. It is also possible to have a configuration in which these are combined as appropriate.

(6) Since the cylindrical rotary transformer is provided on the opposite side of the magnetic pole surface direction of the rotor magnet 8 of the motor, magnetic disturbance to the rotary transformer can be reduced, and the installation work of the rotary transformer, head terminal, and It is also easy to connect to electronic circuit terminals etc. mounted on the board. Furthermore, since the space occupied by the rotary transformer can be limited to the vicinity of the central fixed shaft, the space occupied by the mounted circuit board and the space occupied by the motor can be increased.

(7) Since the central shaft 1 is fixed, a fixed side such as the brush board 32 for power feeding or the slip ring board 86 is fixed to the central shaft 1.

Therefore, the device can be made compact in structure.

(8) Since most of the rotating part is covered between the upper and lower cylinders, the rotational noise of the rotating part is thereby masked and reduced. Furthermore, the vibrations exerted by the rotating part on the running magnetic tape are also extremely small. Therefore, low jitter and low wow/flutter can be easily achieved. Furthermore, since the upper and lower cylinders are both fixed, there is no lifting of the magnetic tape from the cylinder surface, and good contact characteristics between the head and tape can be obtained even under low tape tension, resulting in a high level and high S/N. head signal can be obtained. Additionally, friction and wear on the head tip can be significantly reduced, extending its life.

(9) Since the contact area between the rotating part and the magnetic tape can be made extremely small, there are advantages such as significantly reducing the load and torque of the motor and saving power.

In addition, in this first embodiment, the fixed side magnet 16.20 in the magnetic repulsion generating section was made to have a larger outer diameter than the rotating side magnet 15.19, but on the contrary, the magnet 15. The outer diameter size of the magnet 16.20 may be larger than that of the magnet 16.20, or the inner diameter size may be combined to be larger or smaller. Furthermore, even if the outer and inner diameter dimensions are the same, any structure that allows a radial component to be obtained in the magnetic repulsive force may be used. The dimensions in the thickness direction of each magnet may also be made thicker at the inner peripheral portion, or the rotating side magnets 15 and 19 may have a tapered shape. Number of brushes for power supply,
The number of slip rings may be further increased to three or more. Furthermore, in this embodiment, the supporting force of the rotating part is obtained from magnetic repulsion force and fluid dynamic pressure, but in addition, fluid dynamic pressure is not used together, and all the supporting force is obtained from magnetic repulsion force. Good too.

FIG. 18 is a longitudinal sectional view showing a second embodiment of the rotary head device according to the present invention, in which 6' is a magnetic head, 64' is a screw, 72a, 72b are connectors, 89 is a thrust support piece, and 89a is a Bearing surface, 90 is the center, 91 is the substrate, 92
1 is a holder, 93 is a screw, and parts corresponding to those in FIG. 1 are given the same reference numerals.

In the figure, the lower end of the central shaft 1 is press-fitted into the center of the bottom of the lower cylinder 4, as in the first embodiment.
It is fixed vertically.

A sleeve-shaped central portion 90 of the upper cylinder 2 is engaged with the central shaft 1 with a small gap. This gap is filled with lubricating fluid to form a fluid bearing.

The inner surface of this center portion 90 forms the journal dynamic pressure bearing surfaces 27 and 28 of the hydrodynamic bearing, and these journal dynamic pressure bearing surfaces 27 and 28 are lubricated during rotation, as shown in FIG. 2(a). Means, such as groups, have been implemented to generate fluid journal dynamic pressure.

At the center of the upper surface of the upper cylinder 2, there is a thrust support piece 89 that forms a fluid bearing in the thrust direction with the upper end surface of the central axis l.
is provided. Further, a head fixing base 5' on which a magnetic head 6.6' is mounted is attached to the outer peripheral side of the lower surface of the upper cylinder 2 by screws 64, 64'.

The magnetic head 6,6' projects slightly outward from the gap between the upper cylinder 2 and the lower cylinder 4. The height of the magnetic head 6.6' can be adjusted by screws 70.

The rotor yoke 10 of the motor and a holder 92 are integrally connected to the lower surface of the upper cylinder 2 by screws 93, and the inner surface of the holder 92 and the upper cylinder 2
A cylindrical rotating core 24 of the rotating transformer is attached coaxially with the central shaft 1.

Further, a cylindrical fixed core 23 of the rotary transformer is arranged inside the rotary core 23 and facing the lower cylinder 4.
is attached to. A board 91 is provided near the fixed core 24 at the bottom of the lower cylinder 4, and the wiring on this board 91 is connected to the coil of the fixed core 23 and the connector 72b.

Further, the coil of the rotating core 24 is connected to the wiring of the head fixing base 5' by a lead wire.

Similar to the first embodiment, a rotor magnet 8 is provided on the rotor yoke 10, and a stator coil 9 is provided on a substrate 12 fixed to the lower cylinder 4. A yoke 11 on the opposite side of the rotor magnet 8 is attached to and fixed to the lower cylinder 4. Note that the drive current is supplied to the stator coil 9 via the connector 72a. shield ring 13
prevents magnetic leakage from inside the motor to the outside. Support 9
An annular magnet 19 is provided on the lower surface of the cylinder 2 coaxially with the central axis 1, and an annular magnet 20 is provided at the bottom of the lower cylinder 4 opposite to this. These magnets 19 and 20 are magnetized so that their opposing magnetic pole faces have the same polarity, and constitute a magnetic repulsion generating section.

The magnetic repulsion generating means consisting of the magnets 19 and 20 can be configured as shown in FIGS. 3 to 11.

In such a configuration, in the rotating state, the thrust load bearing force of the magnetic repulsion by the magnets 19, 20 and the floating blade due to the thrust dynamic pressure on the bearing surface 89a of the thrust bearing piece 89 are added, and this and the own weight of the rotating part are Support in the thrust direction is achieved with a balance between the two. Further, the centrifugal force of the rotating part and the journal dynamic pressure on the journal dynamic pressure bearing surface are balanced with the journal load bearing force by the magnets 19 and 20. Thereby, the rotating part floats from the fixed part in a non-contact state.

Therefore, also in this embodiment, the magnet 19.
If the amount of magnetic flux 20 is increased to increase the magnetic repulsion force, the bearing force burden due to the dynamic pressure on the bearing surface 89a and the journal dynamic pressure bearing surfaces 27 and 28 can be reduced, and as described in the first embodiment, Stable bearing with low friction is possible. Further, in this embodiment, since thrust dynamic pressure is generated at the tip of the central shaft 1, fluid friction can be reduced. Furthermore, yoke 1
1 is fixed, the entire rotating part including the upper cylinder 2, motor rotor, and magnetic head 6.6' can be pulled upwards to separate the device, allowing for replacement and adjustment of the magnetic head 6.6', motor Inspection of the rotor and maintenance of the dynamic pressure and magnetic repulsion generation parts are extremely easy.

FIG. 19 is a longitudinal sectional view showing a third embodiment of the rotary head device according to the present invention, in which 4a is a cylindrical portion, 23' is a fixed core of a rotary transformer, 24' is a rotating core of this rotary transformer, and 91 91' is a board, 94 is a short circuit coil, 95 is a magnet for generating a speed control signal (FG double signal, 96 is a magnet (tack magnet) for generating a head position detection signal, 97 is a board, 98 is a tack sensor, 99 .10
0 is a connection pin, 101 to 103 are connectors, and the first
Parts corresponding to the figures are given the same reference numerals.

In this embodiment, a changing magnetic field is applied to a fixed short-circuited conductor (short-circuit coil) by the rotation of a rotating part to generate an induced current, and the rotating part floats due to the repulsive force caused by the interaction between this magnetic field and the applied magnetic field. It was designed to give a blade,
Its basic structure is the same as that of the first embodiment, with an upper cylinder 2 and a lower cylinder 4 fixed to both the upper and lower ends of the central shaft 1, and a rotating disk 3 with a magnetic head 6 fixed in the middle between these cylinders. is rotated by a direct-coupled motor with a built-in cylinder.

In FIG. 19, a shorting coil 94 is provided on the board 12 within the motor, overlapping the stator coil 9. When a drive current is supplied from the connector 72 to the stator coil 9 to rotate the motor, the magnetic field of the rotor magnet 8 is applied to the shorting coil 94 as a changing magnetic field, and this shorting coil 9
4, an electromotive force corresponding to this changing magnetic field is induced, and an induced current flows. This induced current generates a magnetic field from the short circuit coil 94, but the direction of this magnetic field is the same as that of the rotor magnet 8.
Therefore, a magnetic repulsion force is generated between the short-circuit coil 94 and the rotor magnet 8, and the rotating part receives the floating blade in an upward direction parallel to the central axis 1.

This floating blade is determined by the magnitude of the induced current in the short circuit coil 94, the strength of the magnetic field applied to the short circuit coil 94, and the magnitude of the induced current in the short circuit coil 94.
It is proportional to the product of 4 effective lengths. Note that the shorting coil 94 may be formed as a patterned conductor on the substrate 12.

On the lower surface of the rotor yoke 11 of the motor attached to the rotating sleeve body 7, there are provided a circumferentially multi-pole magnet 95 for generating an FG signal and a predetermined number of tack magnets 96. An FC signal sensor and a tack sensor 98 (not shown) are provided on a substrate 97 attached to the inner step of the lower cylinder 4. While the motor is rotating, the obtained FG multiplied signal tack pulses pass through the wiring on the board 97 and are led out from the connector 103 to an external circuit.

In this embodiment, two rotary transformers are provided to support multi-head mounting and multi-channel transmission. transformer, others are fixed core 2
3', a rotating transformer consisting of a rotating core 24'. That is, the bottom of the lower cylinder 4 is provided with a cylindrical portion 4a into which the central shaft 1 is press-fitted, and the cylindrical fixed core 23' of the rotary transformer is attached to the outer peripheral surface of this cylindrical portion 4a. Also,
A rotating core 24' of this rotating transformer is attached to the rotating sleeve body 7 opposite to this fixed core 23'.

The coil terminal of the fixed core 23 is connected to the wiring terminal of the board 91 attached to the fixed piece 14, and the coil terminal of the fixed core 23' is connected to the wiring terminal of the board 91 attached to the bottom of the lower cylinder 4.
’ is connected to the wiring terminal. The wiring on the board 91' is connected to an external circuit by a connector 102.

Furthermore, the M2O covers not only the recess provided in the fixed piece 14 for storing the lubricating fluid 29, but also the substrates 35 and 36 provided on the upper surface of the upper cylinder 2 and the electronic components thereon. The connector 101 connects the wiring on the board 35 and an external circuit. Furthermore, the wirings on the substrates 36 and 91 are connected by connection pins 100, and the wirings on the substrates 37 and 38 are connected by connection pins 99, respectively.

The configuration and operation other than the above portions are the same as the embodiment shown in FIG.

FIG. 20 is a circumferential developed view schematically showing an example of the relationship among the rotor magnet 8, stator coil 9, and short-circuit coil 94 in FIG. 19, and 104 is a drive circuit, which corresponds to FIG. The same parts are given the same symbols.

A drive current is passed from the drive circuit 104 to the stator coil 9,
Rotate the motor in the direction of the arrow at angular velocity ω (rotational thrust F
& ) and the magnetic flux φ from the rotor magnet 8 sequentially interlinks with the short circuit coil 94 as shown by the broken line arrows, and generates an induced current in the short circuit coil 94 due to the electromotive force in the direction shown by the arrow. The magnetic field generated by the induced current in these short-circuited coils 94 faces the magnetic field from the rotor magnet 8 with the same polarity, and provides the rotor magnet 8 with a repulsive floating blade F2. Here, Fig. 21 (al, (b)
), the opening angle of the short-circuit coil 94 is selected to be approximately □ the magnetic pole opening angle of the rotor 7 magnet 8.

However, FIG. 21(a) is a plan view of the magnetic poles of the rotor magnet 8, and FIG. 21('b) is a schematic plan view of the stator. In addition,
In Figure 21, the number of magnetic poles of the magnet is 8, and the number of coil poles is 3.
It has 6 phase coils.

FIG. 22 shows the magnetic flux densities B, B2, interlinkage magnetic flux amount φhφ2, and starting force e in the short-circuited coils ■ and ■ in FIG.

l+e02, levitation blade F gl+ F z □ is a diagram showing temporal changes, in which (a) to (d) in the figure relate to the short-circuited coil ■, and (e) to (hl in the same figure relate to the short-circuited coil ■). As shown in FIG. 22(i), the resultant force of the floating blades F□ and F2□ in these short-circuited coils ■ and ■ becomes approximately constant.

FIG. 23 is a developed view showing another specific example of the magnetic repulsion force generating section using the short-circuited coil in FIG. 19, 94a, 94b
is a shorted coil.

In this specific example, short-circuiting coils 94a and 94b with a coil opening angle equal to the magnetic pole opening angle of the rotor magnet 8 are provided with a pitch shifted by one opening angle. 94b are arranged one on top of the other, and FIG. 9(b) shows the case where they are arranged slightly shifted from each other. In the configuration shown in FIG. 3A, when each short-circuiting coil is formed of a patterned conductor or the like, for example, short-circuiting coils 94a are provided on each of the front and back sides of the substrate 12.

This can be easily achieved by forming the portions 94b separately. In the case of the same figure (a), the short-circuited coil 9 is shorter than the case of the same figure (b).
The conductor lengths of 4a and 94b can be made longer.

FIG. 24 is a waveform chart showing the electromotive force e0, floating blade F2, etc. generated in these short-circuited coils 94a and 94b. 22nd
As in the case of the figure, B, φ+ eol F +1 respectively indicate the magnetic flux density, magnetic flux linkage, starting force, and floating blade, the suffix 1 indicates what occurs in the short-circuited coil 94a, and the suffix 2 indicates the short-circuited coil. 94b are shown respectively.

FIG. 25 is a developed view showing still another specific example of the magnetic repulsion generating section using the short-circuited coil in FIG. 19, and parts corresponding to those in FIG. 23 are given the same reference numerals.

In the figure, the magnetic pole opening angle of the rotor magnet 8 is combined with a short-circuited coil 94b whose phase is shifted by □ψ from this to form a two-phase structure.

FIG. 26 shows an example of the planar configuration of the motor stator in this specific example. Here, an FG pattern conductor 95' is also arranged simultaneously on the surface of the base Fi 12, in place of the magnet 95 for generating the FG signal in FIG. 19, along with the stator coil 9 and the short circuit coils 94a and 94b. The functions and effects of this specific example are similar to those of the specific example described in FIGS. 19 to 24 above.

FIG. 27 is a vertical sectional view of a main part showing a first modification of the embodiment shown in FIG. 19, in which 8' is a rotor magnet;
0' is a rotor yoke, and parts corresponding to those in FIG. 19 are given the same reference numerals.

In the figure, in the motor, a rotor magnet 8, a rotor yoke 9, a stator coil 9, a short-circuit coil 94, a substrate 1
2, the rotor magnet 8'
, a rotor yoke 10' is provided.

FIG. 28 shows a developed view in the circumferential direction of the motor having such a configuration.

In the figure, the magnetic pole faces facing the rotor magnets 8 and 8' have different polarities, and a magnetic repulsion force Fz parallel to the central axis 1 and directed upward is generated between the rotor magnets 8 and the short-circuited coils 94. occurs, causing rotor magnet 8' and short-circuit coil 9.
4, there is a magnetic repulsion force F in the opposite direction to the magnetic repulsion force F□
g! occurs.

Now, in Fig. 29, the horizontal axis indicates the position in the thrust direction,
If we take the magnetic repulsion force F between the rotor magnet 8.8' and the short-circuited coil 94, the weight W of the rotating part, and the thrust dynamic pressure Fzf generated on the thrust dynamic pressure bearing surface 26 on the vertical axis, then the rotor magnet 8', A force that pushes down the rotating part is made up of the sum of the magnetic repulsion force Fz□ by the short-circuiting coil 94 and the own weight W of the rotating part, the magnetic repulsion force F11 by the rotor magnet 8 and the short-circuiting coil 94, and the force generated on the thrust dynamic pressure bearing surface 26. The rotating part is stabilized at a height position Z0 relative to the point P where the force for pushing up the rotating part, which is the sum of the thrust dynamic pressure Fzf, is balanced.

Therefore, in this embodiment, even if the attitude of the device changes, the supporting position and performance can be maintained constant.

FIG. 30 is a longitudinal sectional view of a main part showing a second modification of the embodiment shown in FIG. 19.

FIG. 30 (al is a stator consisting of a substrate 12 including a short-circuit coil 94 and a yoke 11 is tilted with respect to a plane perpendicular to the central axis 1 so that the central axis 1 side is lower, and the magnetic poles of the rotor magnet 8 are The surface is also inclined so as to be parallel to the surface of the stator.

According to this configuration, the magnetic repulsion force generated by the rotor magnet 8 and the short-circuited coil 94 generates an upward thrust load bearing force, and also generates a journal load bearing force in the direction of the central axis 1, giving a centripetal force to the rotating part.

In FIG. 30(b), the magnetic pole faces of the stator and rotating magnet 8 are tilted in the opposite direction to FIG. 30(a),
The generated journal load bearing force applies centrifugal force to the rotating part.

Fig. 30 TC) rotates the yoke 11,
Only the stator is tilted. This is also shown in Figure 30 (al,
The same effect as (b) can be obtained.

In this manner, in these modified examples, since the journal load bearing force is applied to the rotating portion in addition to the thrust load bearing force, the bearing stability can be further improved.

In FIG. 30fc), by making the magnetic pole face of the rotor magnet 8 parallel to the stator, the -layer support stability is further improved.

In addition, in these modified examples, as shown in FIG. 27, two rotor magnets may be provided sandwiching the stator, and the same effect can be obtained by fixing the short-circuit coil 94 at an angle. .

FIG. 31 is a sectional view of main parts showing a third modification of the embodiment shown in FIG. 19, in which 105 and 106 are magnets;
107 is a rotating yoke, 108 is a magnet, and the first
Parts corresponding to those in FIG. 9 are given the same reference numerals.

In this modification, a magnetic repulsion generation section using a short-circuited coil and a magnetic repulsion generation section using a unipolar magnet are provided in the motor.

In the modification shown in FIG. 31 (al), a short-circuit coil 94 and a stator coil 9 are stacked and provided on a stator substrate 12, and these are arranged to face the rotor magnet 8, and the inside of the stator coil 9 is stacked. An annular magnet 106 is provided on the circumferential side, and an annular magnet 105 is provided on the inner circumferential side of the rotor magnet 8 so as to face each other.The induced current of the short circuit coil 94 and the magnetic field from the rotor magnet 8 cause As described above, a magnetic repulsion force is generated that causes the rotating part to levitate.

Further, the magnets 105 and 106 are magnetized so that the opposing magnetic pole surfaces have the same polarity, thereby generating a magnetic repulsion force that levitates the rotating part.

The magnets 105 and 106 can also be constructed as shown in FIGS. 3 to 11, and can provide not only an upward thrust load bearing force but also a journal load bearing force. Further, the shorting coil 94 may be formed of a patterned conductor on the substrate 12.

In the modification shown in FIG. 31 [b], the rotary yoke 11 is brought close to the stator, and a magnetic attraction force is generated between the magnet 106 and the rotary yoke 11, which also serves as a thrust load bearing force. , other configurations and functions are described in Part 3.
This is the same as the modification shown in FIG. 1 [a].

The modified example shown in FIG. 31(C) is one in which a magnet 108 is provided on the rotating yoke 11 opposite to the magnet 106, and the other configuration and operation are the same as the modified example shown in FIG. 31(bl). The magnets 106 and 108 are magnetized so that the magnetic pole faces facing the magnet 106 have the same polarity, and along with the upward magnetic repulsive force of the magnets 106 and 105, the magnets 106 and 108
This creates a downward magnetic repulsion force.

In the modification shown in FIG. 31(d), a ζ magnet 8' is further provided in the rotating yoke 11 of the modification shown in FIG. 31(e) so as to sandwich the magnet 8 and the stator. be. This is similar to the motor shown in FIGS. 14 and 15 in which a short-circuit coil 94 is provided in a stacked manner with the stator coil 9.

Here, in the modified example shown in FIGS. 31(C) and (d), the relationship between the magnets 105, 108, and 106 is the same as that of the magnet 83°84 in the specific example shown in FIGS. 14 and 15.
．． 85, and the same magnetic repulsion force as in these specific examples can be generated.

According to these modifications shown in FIG. 31, the short-circuit coil 9
Even in a stationary state where no induced current is generated in the rotor 4, the floating blade by the magnet 106 is in effect, making it possible to support the rotating part in a non-contact state or in a low-friction contact state. Further, in the rotating state, since the magnetic repulsion force from both the short-circuit coil 94 and the magnet 106 can be added together for support, high stiffness support can be achieved even under low friction conditions.

Next, other specific examples of the magnetic repulsion generating section for obtaining the journal load bearing force in each of the above-described embodiments will be described.

FIG. 32 is a sectional view showing such a magnetic repulsion generating section, and ? a, 7b are depressions, 109 a.

109b is a magnet, 110a and 110b are yokes made of magnetic material, and parts corresponding to those in the previous drawings are given the same reference numerals.

In the figure, cylindrical recesses 7a and 7b are provided on the upper and lower end surfaces of the rotating sleeve body 7, respectively, and a cylindrical magnet 109a and a yoke 110a are provided in the recess 7a.
are provided coaxially with the central axis 1, and a cylindrical magnet 109b and a yoke 110b are provided coaxially with the central axis 1 in the recessed portion 7b.

As shown as the magnet 109 in FIG. 3, the magnets 109a and 109b are composed of magnetic poles of different polarity arranged alternately in the circumferential direction. A magnetic repulsion force F in the journal direction is generated between the center axis 1 and the center axis 1.

FIG. 34 is a diagram expanded from FIG. 33 in the circumferential direction to show the principle of generation of this magnetic repulsion force. In the figure, when the magnet 109 rotates at an angular velocity ω, the magnetic flux φ generated by the magnet 109 induces eddy currents i in various parts of the surface of the central shaft 1, and the interaction between the eddy current i and the magnetic flux φ causes the journal A magnetic repulsion force F in the direction is generated. As a result, the magnet 109 floats above the surface of the central shaft 1.

FIG. 35 shows still another specific example of the magnetic repulsion force generating section for obtaining journal load bearing force, and shows 11
1a is a conductor, and parts corresponding to those in FIG. 32 are given the same reference numerals.

In the figure, a conductor 111a is provided on the surface of the central axis 1, facing the magnet 109a.

When the magnet 109a rotates, an eddy current is generated in the conductor 111a, thereby providing a magnetic repulsion force in the journal direction. If a high conductivity material such as copper is used as the conductor 111a, a large eddy current can be obtained in the conductor 111a even when the magnet 1098 or the like is a small component, and as a result, a large journal load bearing force can be obtained. The concave portion 7b in FIG. 32 also has a similar configuration.

As shown in FIG. 36, magnets 109a and 109b may be provided on the outer peripheral surface of the rotating sleeve body 7. In this case, the inner circumferential surface of the rotating sleeve body 7 can be used as a journal dynamic pressure bearing surface 27, 28, and can also be used as a fluid bearing in the journal direction together with the central shaft 1.

Note that also in the specific examples shown in FIGS. 32 and 35,
Recessed portion 7a in rotating sleeve body 7.

The inner surface between 7b may be used as a journal dynamic pressure bearing surface to form a fluid bearing with the center shaft 1.

The specific example shown in FIG. 37 is the conductor 111 in FIG.
Instead, a shorting coil 112 is provided on the surface of the central axis 1, and a magnetic repulsion force in the journal direction is generated by the current induced in the shorting coil 112 and the magnetic field of the magnet 109.

A pattern conductor formed on an insulating sheet 113 may be used as the short circuit coil 112, and this insulating sheet 113 is connected to the central axis 3.
Wrap it around the surface of 7.

In the specific examples shown in FIGS. 32 to 37, high-performance bearing characteristics such as low friction and high reliability are obtained, similar to the above-mentioned magnetic repulsion generation section, and it is possible to combine with these magnetic repulsion generation sections. As a result, a stable and high-performance rotary head device can be easily realized.

In addition, in the embodiment described above, a flat motor of a plane-opposing type is used as a drive motor.
Other types of motors, such as an outer rotor type motor with the same circumferential surface, may also be used. Further, although the central shaft 1 is fixed to the bottom surface of the lower cylinder 4, the structure is not limited to this, and the central shaft 1 may be configured to rotate, and the motor may be provided outside the cylinder. Furthermore, in the configuration in which fluid dynamic pressure is used together, the dynamic pressure generation group is provided on the journal dynamic pressure bearing surfaces 27 and 28 of the rotating sleeve body 7 and the thrust dynamic pressure bearing surface 26 of the rotating sleeve body 7. The structure is not limited to this, and may be provided on the outer circumferential surface of the central axis l facing these surfaces, or may be provided on a parallel portion provided on the surface of the thrust support piece 25. Furthermore, the shape of the dynamic pressure generating group is not limited to the shape shown in FIGS. 2 and 3. Furthermore, as the lubricating fluid, not only green, oil, etc. but also air may be used, and when air pressure is used, a static pressure system may be used instead of a dynamic pressure system.

〔Effect of the invention〕

As explained above, according to the present invention, (1) a magnetic repulsion force component in the journal direction can be generated in addition to the thrust direction in the support of the rotating part, so it is possible to realize a stable non-contact support with high centripetality; .

(2) Since the rotating part is supported by magnetic repulsion, wear due to rotation can be extremely reduced, the life of the supporting part can be extended and the reliability can be increased, and at the same time, the power consumption of the drive motor can be reduced.

Additionally, disturbances caused by the bearing portion can be eliminated, resulting in low torque ripple. Furthermore, the effects of ambient temperature and humidity on the bearing characteristics can be eliminated, and the characteristics can be stabilized.

(3) The magnetically levitated blade can be easily controlled by appropriately selecting the strength and distribution of the magnet's magnetic field, the material, shape, dimensions, fixing position, etc. of the induced current generating conductor.

(4) In a configuration in which magnetic repulsion is obtained by generating an induced current in a fixed conductor, a stable bearing force with high stiffness can be obtained. By reducing the conductor resistance, the induced current can be increased to increase the floating blade.

(5) In a configuration in which the rotor magnet of the motor is also used to generate an induced current in the stator and obtain a magnetically levitated blade,
The number of parts can be reduced and a simple structure can be achieved at low cost. Furthermore, magnetic leakage to the outside of the device can also be prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of a rotary head device according to the present invention, FIGS. 2(a) and 2(b) are views showing a hydrodynamic bearing surface of a fluid bearing, and FIGS. 3 to 17 are FIGS. 18 and 19 are longitudinal cross-sectional views showing other embodiments of the rotary head device according to the present invention, and FIG. 20 is a diagram showing a specific example of the magnetic repulsion generating section in FIG. Fig. 21 is an explanatory diagram of the operation of the magnetic repulsion force generation unit by electromagnetic induction provided in the motor in Fig. A schematic plan view, FIG. 22 is a diagram showing the magnetic flux density, interlinkage flux amount, electromotive force, and levitation blade over time in the short-circuited coil in FIG. 20, and FIG.
Figure 9 is a developed view showing another specific example of the magnetic repulsion generating part in the motor, and Figure 24 is a diagram showing the temporal changes in the magnetic flux density, flux linkage, starting force, and floating blade in the short-circuited coil in this specific example. , FIG. 25 is a developed view showing still another specific example of the magnetic repulsion generating section in the motor in FIG. 19, FIG. 26 is a schematic plan view of the stator of this specific example, and FIG. FIG. 19 is a vertical cross-sectional view of a main part showing a modification of the embodiment shown in FIG. 19, FIG. 28 is a developed view of a magnetic repulsion generating section due to electromagnetic induction in this modification, and FIG. 29 is a developed view of this magnetic repulsion generating section. FIGS. 30 and 31 are longitudinal sectional views of main parts showing other modifications of the embodiment shown in FIG. Fig. 33 is a longitudinal cross-sectional view showing a specific example of .
FIG. 4 is an explanatory diagram of its operation, and FIGS. 35 to 37 are longitudinal cross-sectional views showing other specific examples of the magnetic repulsion generating section for generating journal load bearing force, respectively. 1... Central shaft, 2... Upper cylinder,
3...Rotating disk, 4...Lower cylinder, 5...Disc [base, 5'...
...Head fixing base, 6゜6'...Magnetic head, 7...Rotating sleeve body, 8゜8'...
...Rotor magnet, 9...Stator coil,
10.11...Rotor yoke, 12...
- Substrate, 14... Fixed piece, 15, 16. 1
9.19'. 20.20'... Magnet of magnetic repulsion force generating part, 25... Thrust bearing piece, 26...
・Thrust dynamic pressure bearing surface, 27.28...Journal dynamic pressure bearing surface, 29...Lubricating fluid, 78.8
3-85... Magnet of magnetic repulsion force generating part,
94.94a, 94b... Short circuit coil, 105
, 106, 108... Magnet of magnetic repulsion generating part, 109.109a. 109b... Magnet of the magnetic repulsion force generating part in the journal direction, 111a... Conductor, 112.
...Short circuit coil. Figure 2 (a) (b) Figure 3 Figure 4 ((7) Cb) Figure 5
Figure I Figure 6 (a) (b) Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure IQ' Figure 12 Figure 13 Figure 14 (b) (c) Figure 15 Ca) 8' - (b) (c) Fig. 16 (b) Fig. 17 Fig. Q Fig. 21 (a) Fig. 22 R7 3923 Fig. (a) (b) Fig. 24 Fig. 25 Fig. 26 Fig. 2 γ! Fig. 28 Fig. 29 Fig. 30 Fig. M31 Fig. 32 Fig. 33 Fig. 35 (a), Ib) Fig. 36! Figure 37 7 112 7/3

Claims (1)

[Claims] 1. A rotating part to which a magnetic head is attached is supported by a fixed part, and the rotating part is rotated by a motor,
In a rotary head device in which the head scans a strip-shaped recording medium running along the outer peripheral surfaces of the rotating portion and the fixed portion, a magnetic repulsion generating portion is provided as a means for supporting the rotating portion. Features a rotating head device. 2. In claim 1, the magnetic repulsion generating section is a unipolar magnet that is attached to the rotating section and the fixed section so as to face each other, and is magnetized so that the opposing magnetic pole surfaces have the same polarity. A rotating head device comprising: 3. In claim 2, the magnet has an annular shape,
A rotating head device characterized by being arranged coaxially with respect to a central axis. 4. In claim 3, at least one magnetic pole surface of the magnet relates to a surface parallel to the rotation surface of the rotating part,
A rotating head device characterized by being tilted. 5. The rotary head device according to claim 3, wherein one of the magnets is provided with an annular groove along the circumferential direction. 6. The rotary head device according to claim 3, wherein an annular non-magnetized region along the circumferential direction is provided on one opposing surface of the magnet. 7. The rotating head device according to claim 2, wherein one of the magnets is a plurality of magnets arranged at equal intervals. 8. The rotary head device according to claim 2, 3, 4, 5, 6 or 7, wherein one of the magnets is provided on the rotor of the motor, and the other magnet is provided on the stator of the motor. 9. In claim 1, the magnetic repulsion generating section is configured such that a first annular magnet faces the rotating part and a second annular magnet faces the fixed part, coaxially with a central axis. and an annular third magnet is attached between the first and second magnets so as to be rotatable about the central axis, and the opposing magnetic pole surfaces of the first and third magnets and the second, A rotary head device characterized in that opposing magnetic pole surfaces of the third magnet have the same polarity. 10. In claim 1, a plurality of short-circuited coils are provided on the stator of the motor along the magnetic pole surface of the rotor magnet of the motor, and the magnetic repulsion generating section is arranged between the short-circuited coils and the rotor magnet of the motor. A rotating head device comprising: 11. In claim 10, magnets are provided facing each of the stator and the rotor and coaxial with the central axis, and the opposing magnetic pole faces of the magnets are made to have the same polarity. A rotary head device that generates magnetic repulsion for supporting parts. 12. The rotary head device according to claim 1, wherein the magnetic repulsion generating section includes a central axis and a cylindrical magnet provided at a portion of the rotating section that engages with the central axis. 13. The rotary head device according to claim 12, wherein a conductor is provided on an outer circumferential surface of the central axis facing the magnet. 14. The rotary head device according to claim 12, wherein a plurality of short-circuit coils are provided on an outer peripheral surface of the central shaft facing the magnet.