JPS59113568A - Rotation driving motor of recording disc - Google Patents

Abstract

PURPOSE:To make a recording disc device small in size, by notching a part of a stator as a radial feeding unit storage space to prevent a radial feeding unit from being projected from a recording disc. CONSTITUTION:A stator 7 constituting a rotation driving motor is partially notched into a fan shape, and one ends of radial feeding units 3a and 3c are inserted to this cut open part 80. If the stator 7 is expanded linearly, it has a comb-shaped block form as shown in Fig. When three-phase sinewave currents whose phases are shifted from one another by 60 deg. are applied to terminals T1, T2, and T3, a sine-shape shifting magnetic field is generated in the part of the stator 7. The shifting magnetic field is formed with lines of magnetic force passing through comb teeth of the stator 7, a rotor 8, an opposite magnetic plate 9, etc. An eddy current is generated in the direction accordant to the right-hand rule in the place where the line of magnetic force pass through the rotor 8, and an electromagnetic force is generated between this eddy current and the line of magnetic force, and the rotor 8 is rotated by this electromagnetic force. Its direction is accordant to the left-hand rule.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a motor for rotationally driving a recording disk, and more particularly to a motor for rotationally driving a recording disk that can be applied to an optical disk device or a magnetic disk device.

(Prior Art) As a recording disk device, conventionally, as shown in FIG. The motor 4' that rotates the motor 4'
Optical disk devices equipped with the following are known.

In this optical disk device, the motor 4' has a cylindrical shape and is placed directly below the turntable 5' on which the optical disk 2' is placed as shown in the figure. 3' yoke 3
a' and the permanent magnet 3b' must necessarily be placed outside the motor 4'.As a result, in order to secure the required stroke amount for recording and reproduction by the optical pickup 1', The permanent magnets 3b' and 3b' must also be configured to protrude to the outside of the optical disk 2'.

Therefore, the optical disk device has the drawback of being large in size as a whole.

(Objective) Therefore, an object of the present invention is to provide a disk rotation drive motor that allows the arrangement of nine radial feed units close to the rotational axis of the disk, thereby reducing the size of the recording disk device.

According to the above-mentioned object of the present invention, there is provided an induction motor in which a part of the stator has a notched recess as a radial feeding Schnitt housing space.

(Structure) The structure of the present invention will be described below based on one embodiment.

FIG. 2 shows a cross section of the main part of an optical disk device using a rotational drive motor according to the present invention.

As shown in the figure, a yoke 3a, a permanent magnet 3b, a coil 3
One end of the radial feeding unit 3 consisting of C, etc. is arranged closer to the rotation axis 6 of the optical disk 20 than in the prior art, and moreover, the entire radial feeding unit 3 is located within the space of the optical disk 2. It is contained in Even when the optical disk 2 is disposed in such a space, the required stroke of the optical pickup 1 can be sufficiently secured.

The reason why the radial feed Schnitt 3 can be brought close to the rotating shaft 6 in this way is that, as shown in FIG. This is because the arrangement is such that one end of the radial feed schnit 3 is inserted into the notched recess 80. The rotor 8, which is paired with the stator 7, is made of a conductive disk, such as a copper plate, that is integrally axially symmetrical with the rotating shaft 6. The ports 8 and 8 face the stator 7 with a gap therebetween. Further, above the rotor 8, an opposing magnetic plate 9 is disposed with a gap therebetween and is supported by a magnetic plate support member 10 curved in an arc shape.

This opposing magnetic plate 9 is made of a plate-shaped magnetic material, and the stator 7
The extension of the surface of the size opposite to is 9.

Next, when the stator 7 is expanded into a linear shape, it has a comb-like block shape as shown in FIG.

Note that the virtual line indicates the outline before development. Coils are wound around each comb tooth T with a phase shift. The surface 7a corresponding to the top of each comb tooth is arranged to face the rotor 8 with a gap in the assembled state of the motor.

As shown in Figure 5, the winding mode of the coil is a coil CI that winds the first to third comb teeth on the left.
+ Comb teeth 1, such as the coil C2 that winds the comb teeth from the second to the fourth on the left, and the coil C3 that winds the comb teeth from the third to the fifth on the left. Shift the phase by the main amount, and do the following in the same way as CI', C2ZC3, C+, C
2, Cs, C+, C2, and Ca coils are formed. Here, coils C, ,C, and coil C4'.

C8 has opposite winding directions, coil C2, C2 and coil C
2′.

c Asahi The winding directions are opposite to each other, coil C3+ C3'' and coil 03'.

C, "Iti winding directions are opposite to each other. Furthermore, the coil itself.

Cj+CI+CI are connected and their common terminal is indicated by the symbol T1; coils C2, C2, C2, C2 are connected and their common terminal is indicated by the symbol T2;
Coil c3. c3. C3 and C3 are connected and their common terminal is indicated by the symbol T3.

When three-phase sinusoidal currents whose phases are shifted by 60°3 are applied to each of the terminals 'l + r T2 + Ts, a sinusoidal moving magnetic field is generated in the stator 7 section. The moving magnetic field is formed by lines of magnetic force passing through the comb teeth of the stator 7, the rotor 8, the opposing magnetic plate 9, and the like. The rotor 8 is rotated by the moving magnetic field, which is based on the principle of a so-called polyphase induction motor.

That is, an eddy current is generated in a direction according to the right-hand rule at a portion where the lines of magnetic force penetrate the rotor 8, and an electromagnetic force is generated between the eddy current and the line of magnetic force, and the rotor 8 is rotated by this electromagnetic force. And the direction will be based on the left-hand rule.

Incidentally, let's consider the rotational speed of the rotor 8.

Now, the phase of each terminal Tl, T2 p T3 is 60°
Three-phase sinusoidal currents I,, I2. If I3 is applied and the progression of time is fixed at an arbitrary point in time, a magnetomotive force will be exerted on the coil connected to the terminal T1, as shown in FIG. 5, for example. However, the figure shows only the fundamental wave component.

The magnetomotive force due to the above electric current is FI, and the magnetomotive force due to the current ■2 is F2. If the magnetomotive force due to current ■3 is F3, each magnetomotive force is expressed by the following equations (1), (2), and (3).

F+ =-K I, sinθ ---(1
) pinch, χ is the distance from the 0 point. Here, each current 11-I2. The maximum value of I3 is ■. given that,
It is expressed as the following equations (4L (5), (6) (where ω is the current angular frequency and t is time).

J,=Jocosωt sea (4
)I2-I. cos (ω = m) ... (5
) Is = Io cos (ωt ---E)
--- (6) Therefore, the magnetomotive force F in region A where the magnetomotive force by each coil is superimposed is calculated from (1) to (
When calculated using equation 6), the following equation (7) is derived.

F = Fl +F2 + F3 Part 5 inches (+nt-17) Since the position where the large magnetomotive force is generated moves with t, its moving speed ν can be calculated by differentiating the above rangefinder χ with respect to time t, and then V:
=a= Sen and request 1: Y... so Tetsusa.

In other words, the magnetomotive force moves at a certain speed, and the rotor 8 is also rotated at the same speed.

In the above, although a moving magnetic field is generated in the B area and the 13' area which are outside the A area, the influence of this can be almost ignored in the overall situation, and the magnetic field moves at the above speed V. It can be considered that

Therefore, in order to control the speed of the rotary drive motor according to the present invention, the current angular frequency ω is determined by giving the required speed based on the relationship y - plate ω, and the three-phase current of this constant current angular frequency is controlled. One method is to supply it to the motor and control it using an open loop control method, or the other is to attach an encoder that generates rotation pulses to the rotating shaft and control it using a feedback control method that changes the current angular frequency ω or the current amplitude depending on the magnitude of this frequency. It is possible that

In the above example, since the rotor 8 is a non-magnetic conductor,
No magnetic attractive force is generated between the magnetic circuit and the bearing 60 of the rotating shaft 6, and no overload phenomenon occurs on the bearing 60 of the rotating shaft 6.
It has the advantage that it does not generate any force that would knock down the 5-rotation sting 16, even though it is a part with a notched part.

(Effects) Since the motor for rotationally driving the recording disk according to the present invention has a part of the stator cut out as a space for accommodating the radial feed unit, the radial feed Schnitt does not protrude beyond the recording disk. The device can be downsized.

[Brief explanation of the drawing]

FIG. 1 is a front view of the main parts of an optical disk device according to the prior art;
Fig. 2 is a cross-sectional view of a main part of an optical disc device to which the present invention is applied, Fig. 3 is a cross-sectional view taken along line H-H in the same figure, Fig. 14 is a perspective view showing a state in which the stator is unfolded in a straight line; FIG. 5 is a diagram illustrating the relationship between a linearly developed stator and an arbitrary coil within the stator and the magnetomotive force of the stator. 6... Rotating shaft, 7... Stator, 8... Rotor,
80...Concavity, self + CI + CI + C2+
C2+ C2r C2+ C3+ c3pC3, C3・
coil. Procedure Headquarters j:c-:,t; <Voluntary) 1974
1 υ, 1.1,111 Kazuo Wakasugi, Commissioner of the Japan Patent Office l Display of the case 1982 Patent Application No. 223306 2 Name of the invention (4: Motor for rotational drive of recording disk 3 Relationship with the case of the person making the amendment Patent Applicant name (G74) Ricoh Co., Ltd. 4th generation
Address: 4-5-4 Kyodo, Ichitani-ku, Seguchi-ku, Tokyo "Detailed description of the invention" and "Brief description of the drawings" in the specification
! It f-n and drawings (1) Add the following sentence to the bottom line of the second page of the specification. [Also, since conventional cylindrical motors are constructed as one independent unit, the outer diameter of the motor must be increased in the radial direction in order to obtain the 1 to 1 torque required to change the rotational speed to high speeds. If this is not the case, it is necessary to increase the height dimension, so it is not possible to make the recording tape device thin. (2) In the first line of page 1 of the same page, replace ``pickup j'' with ``a recording ILT generation element such as a pickup or magnetic head for transmitting and receiving information.'' To (), add "or +20°J" next to "60°" in the 7th line from below. (4) Add [XJ to the end of the 8μ, 2nd line. (5) Add In the 9th line of the 8th page, add ``slip'' next to ``ko, 11, and'' (6) Change the ``movement'' in the 11th line of the 8th page to ``like the above.'' Replaced with ``Transfer! II Not a magnetic field''. (7) Add the following sentence at the end of the 9th line.
I will explain.The symbol 8 used once in the same figure is Traditional 1!11
To avoid confusion, the same thing as above is used as long as there is no confusion. The difference between the second example and the above example is θ) in the structure of the stator, yoke, and rotor. First, regarding the stator, it is indicated by the reference numeral 7000 in FIGS. 13, 7b to 8. This stator 7000 has a shape in which a comb-shaped block 7 shown in FIG. 4 is curved into an R++ shape shown by imaginary lines in FIG. 8. A coil C is wound around the comb teeth r in accordance with the configuration explained in FIG. 1 above. Next, the rotor is indicated by the reference numeral 5000, and is made of a conductive plate material, and rotates around its center with the cup shape turned upside down. The stator 7000 is configured to surround the rotor 5υ00 on the outside of the rotor 5000. That is, the stator 7000 has a C-shaped outer shape that looks like a part of an annular ring is cut out. The rotor, yoke, rotating shaft, etc. are surrounded by a concave part of the ring, and a large number of comb teeth (1) are provided in the direction of the center of the ring. This yoke 9000 is fixed to an immovable member inside the rotor 5000, and supports a rotating shaft 6000 inserted into the central hollow part of the yoke 9000 with an axis 'j:I:lO(l). Thus, the stator 7U00 faces the yoke rJoo with the rotor 5000 in between, and the moving magnetic force is generated toward the rotating shaft 6000. In this first row, the radial feeder 1.3000 is It is set at a position facing the stator 7000 with the rotor 5U00 in between, and can be placed close to the rotor 5000. By increasing the space outward in the radial direction, the number of turns of the coil can be increased and the magnetomotive force can be increased.Also, even if there is a restriction on the height of the motor, the space in the radial direction can be increased. As the number of turns of the coil increases, the size of the stator increases, the depth of the groove increases, and J increases, so the motor produces an output of 11-111-lux (47). (No. 2) No. 9α lower or I:, at the end of the 5th line, “Also, j*
Since the magnetic circuit can be enlarged in the radial direction, a thin device can be achieved. 1 (1;) Next to the ``Explanatory diagram'' in the 3rd line of page 10, [Fig. Figure 7 is a +1-II lv1 side view of the main part of the C-screw device, Figure 23 is the first diagram σ) Actual I)
6+1 explaining the shape of the stator using cloth examples? J
,',Add Figure 1, (10) Add Figures 7 and 8 to 5f'l i
lt serial number) Add.

Claims (1)

[Claims] A recording disk device including a radial feeding unit that moves a big amplifier in the radial direction of the disk, and a motor that rotationally drives the disk, which is integral with and axially symmetrical to the rotational axis of the disk. an electrically conductive rotor arranged opposite to the rotor with a gap therebetween;
ζ stator, a part of the stator has a notch-shaped recess as the radial feeding Schnitt storage space, and coils for generating a moving magnetic field that provide rotational force to the rotor are arranged out of phase. A motor for rotationally driving a recording disk, characterized in that: