JPS6151675A - Magnetic disk device - Google Patents

Abstract

PURPOSE:To solve a mutually contradictory problem of increasing a memory capacity to a large capacity and setting information processing time to high speed by using a stepping motor which can rotate by plural different step angles and operating and controling so that a magnetic head can be shifted up to a cylinder, a goal, in the shortest time. CONSTITUTION:When a stepping motor 1 impresses one excitation pulse to the first stage winding 1 and a mutual excitation is changed over once, a rotary shaft 3 rotates by 0.9 deg., and the motor impresses one excitation pulse to the second stage winding 16, the rotary shaft 3 rotates by 3.6 deg.. When the rotary shaft rotates by 0.9 deg., a magnetic head shifts for one cylinder. A memory circuit 22 adds the excitation pulse inputted to the motor 1 under a control of an operating circuit 24 and stores a position of the magnetic head as a cylinder number. When an inner circumference side shifting signal and a step pulse number are inputted to a memory circuit 23 from an external device 29, the circuit 24 shifts by the smallest excitation pulse number from a present position to a cylinder, a goal. Therefore, the winding to be excited of the motor 1 is operated and the prescribed winding of the motor 1 is excited by an exciting circuit 25.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic disk device, and more particularly to a magnetic disk device that uses a stepping motor to enable high-speed access.

[Prior art]

Generally, a magnetic disk device includes a rotatably provided magnetic disk, a magnetic head for writing and reading information on the magnetic disk, and a carriage for mounting the magnetic head. A magnetic head moving mechanism that moves in the radial direction, and a cylinder or track (hereinafter referred to as "cylinder") that drives the magnetic head moving mechanism and uses the magnetic head as a magnetic disk.
For example, in small magnetic disk devices such as floppy magnetic disk devices, an inexpensive stepping motor is used as the motor.

Incidentally, the stepping motor used in the above-described magnetic disk device is configured such that the magnetic head moves one cylinder in the radial direction when one excitation pulse is applied from an external device such as a main controller. Therefore, as the number of cylinders per side of the magnetic disk increases, the amount of excitation pulses must be increased accordingly in order to move the magnetic head to the target cylinder, and the magnetic head moves to the target cylinder. There is a problem that it takes a lot of time to do this, which increases the access time.

Therefore, some devices have appeared in the prior art in which a plurality of magnetic heads are attached to each surface of a magnetic disk in order to shorten the processing time. That is, when the number of magnetic heads is two, the -10,000 magnetic head has a bridge on the outer circumference side of the total number of cylinders, and the other magnetic head has a structure on the inner circumference half, The aim is to shorten access time and speed up information processing time as a whole. However, as mentioned above, an increase in the number of magnetic heads means that the magnetic head movement mechanism becomes more complicated.
Not only does it lead to an increase in size, it also increases the load on the stepping motor, and it also has the drawbacks of complicating the structure of the control device that selects and controls the magnetic head, and the information writing and reading devices, which leads to increased costs. there were.

[Problem that the invention seeks to solve]

The present invention was made in view of the problems of the prior art described above, and uses a stepping motor capable of rotating a rotary shaft at a plurality of different step angles, and a control device that controls a magnetic head. By using a control device that calculates and controls the cylinder to move in the shortest time, that is, with the minimum number of excitation pulses, we solve the contradictory technical issues of increasing storage capacity and speeding up information processing time. To provide a smooth magnetic disk device [Means for solving the problem] In order to solve the above problem, a stepping sweater is fixed to a rotating shaft, and each step has a different number of teeth. It consists of a multi-stage rotor having a multi-stage rotor, a multi-stage stator corresponding to each rotor, and a plurality of windings independently wound around the stator of each stage, The control device that controls the rotation of the motor includes a first storage circuit that stores the cylinder number on the magnetic disk corresponding to the current position of the magnetic head, and a second storage circuit that stores the number of step pulses input from an external device. Based on the stored contents from the first and second storage circuits, which winding of the stepping motor should be selected in order to move the magnetic head from the current position to the target cylinder with the minimum number of excitation pulses. The motor is comprised of an arithmetic circuit that calculates whether the motor should be excited, and an excitation circuit that outputs pulses to each winding of each stage of the stepping motor according to the calculation result of the arithmetic circuit.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 to 7.

First, FIGS. 1 to 4 show a stepping motor 1 used in this embodiment.

That is, 2 and 2 are left and right casings, and each casing 2 rotatably supports a rotating shaft 3 that is connected to a magnetic head moving mechanism via a bearing. A permanent magnet 4 having N@ and S poles on the left and right sides is fixed to the rotating shaft 3, and on the left side of the permanent magnet 4, a first stage rotor 5 made of, for example, a laminated steel plate is attached to the permanent magnet 4. The rotor 5 has 25 teeth 6, 6 . on the outer peripheral surface thereof. ... is formed. Also, the right side of the permanent magnet 4 is also stratified.
A second stage rotor 7 made of a steel plate is provided at a predetermined distance from the first stage rotor 5, and the outer peripheral surface of the rotor 7 is provided with 50 teeth 8, 8 . ... is formed.

Reference numeral 9 denotes a first-stage stator provided at a position facing the first-stage rotor 5, and the stator 9 has eight poles 10A, I
OB, . A tooth 11 consisting of a convex portion and two concave portions is formed, and a four-phase free winding 12 is wound around the six poles 10. Here, the teeth 6 and 11, which are 1800 pairs identical to each other across the rotating shaft 3, are shifted by half a pitch (as shown in the figure, the protrusions of the teeth 8 and 11 face each other at the pole 10A, but In contrast, 180°
In the opposing pole 10E, the concave portion of the tooth 6 and the convex portion of the tooth 11 are opposed to each other). Also, winding] 2 is ■.

Assuming that ■, ■, and ■ are the first phase, second phase, third phase, and fourth phase, phases ■ and ■ are wound around the pole 10A, and ■,
The ■phase is wound, and the ■ and ■phases are similarly wound around the pole 10H.These windings 12 are independently connected to the excitation circuit 25 later, and excitation pulses are applied to each phase of the winding 12. is configured to apply.

Reference numeral 13 denotes a second-stage stator provided at a position facing the second-stage rotor 7, and the stator 13 also has eight poles 14A.
, 14B, ..., 14H (referred to as pole 14 as a whole)
is provided to protrude toward the center, the inner circumferential surface of the multipole 14 spreads out in a fan shape, and teeth 15 each consisting of five convex portions and four concave portions are formed opposite to the teeth 8. with, 6
A winding 16 consisting of four phases is wound around the pole 14 . Here, the teeth 8 and the bellows 15, which are opposed to each other by 180° with the rotating shaft 3 in between, are shifted by one pitch (as shown in the figure, in the poles 14A and 14E that are opposed to each other, the protrusions of the bacteria 8 and the teeth 15 are opposed to each other). are doing). Still, the winding 16 is wound in the same order as the winding 12 described above, and the winding 16 is also wound in the excitation circuit 25 described below.
is configured to apply excitation pulses to each phase.

Furthermore, 17 is a circular magnetic shielding plate made of ferrite material inserted between the stators 9 and 13 of each stage, and when a pulse is input to the winding 12 or 16 of each stage through the magnetic shielding plate 17. , interference due to electromagnetic induction between the stators 9 and 13 is prevented. The stepping motor J used in this embodiment is configured as described above, but generally the step angle θ, the number of phases m, and the number of teeth of the rotor N in a stepping motor.
There is a relationship between r and The number of teeth of rotor 5 is 25
Since the number of teeth of the second stage rotor 7 is 50, the step angle θ of the first stage rotor 5 is 1.8°, and the second stage rotor 7 also has a step angle θ of 1.8°. This constitutes a stepping motor with a step angle θ of 3.6°.

Next, reference numeral 21 indicates a control device used in this embodiment, and the control device is roughly composed of a first memory circuit 22, a second memory circuit 23, an arithmetic circuit 24, an excitation circuit 25, and a power supply circuit 26. .

Here, the first storage circuit 22 constantly adds (increments) or subtracts (decrements) the excitation pulses input to the stepping motor 1 under the control of the arithmetic circuit 24 to store the current position of the magnetic head on the magnetic disk. This is stored as the cylinder number above.

The second storage circuit 23 is connected to an external device 29 via a direction signal line 27 and a step pulse signal line 28. Under the control of the arithmetic circuit 24, a direction signal related to the direction of movement of the magnetic field is inputted to the magnet via the step pulse signal line 28, and a predetermined number of pulses are inputted to the magnetic field via the step pulse signal line 28. It stores input information.

- The arithmetic circuit 24 operates the magnetic head based on the current position of the magnetic head stored in the first storage circuit 22 and the direction signal and step pulse signal stored in the second storage circuit 23. In order to move from the current position to the target cylinder with the minimum number of excitation pulses, it is calculated which stage and which winding of the stepping motor 1 should be excited. Specifically, it is based on a predetermined calculation formula or program. For example, it operates as shown in the time chart shown in FIG.

Further, the excitation circuit 25 is provided at the next stage of the arithmetic circuit 24, and based on the arithmetic result from the arithmetic circuit 24, the power supply circuit 25
6, the power supply voltage is distributed and output as excitation pulses to each winding 12 and 16 of each stage constituting the stepping motor 1, and the stepping motor includes a conventionally known distribution circuit, winding excitation circuit, etc. be done.

The embodiment of the present invention is constructed as described above, and its operation will now be described with reference to FIGS. 6 and 7.

In the following explanation, for easy understanding, the stepping motor 1 has two stages, the number of windings in each stage is 12.160, the number of phases m is 4, and the teeth of the rotors 5 and 7 in each stage are 6 and 8. Assuming that the numbers Nr are respectively 25 and 100, the step angle θ is 360'/θ=mNr, and the step angle θ of the first stage rotor 5 is 0.9°, similarly as described above. The step angle θ of the second stage rotor 7 is 3.6°. That is,
When one excitation pulse is applied to the first stage winding 12 and the phase excitation is switched once, the rotating shaft 3 rotates by 0.9°, and one excitation pulse is applied to the second stage winding 16. Then, the rotating shaft 3 will be rotated by 3.6 degrees. Also, the first stage volume m1
It is assumed that the magnetic head moving mechanism is set so that when one excitation pulse is applied to the magnetic head 2 and the rotary shaft 3 rotates by 0.9 degrees, the magnetic head moves by one cylinder.

On the other hand, regarding the magnetic disk, the number of cylinders per surface is 320 (hereinafter, each cylinder is referred to as # ``0~319# cylinder J'').The position corresponding to # 0 cylinder is set to the outermost circumferential side, that is, zero. Track position 3] 9 The position to be performed is the innermost side, and each stage I, It (hereinafter, each stage 1.If will be referred to as "1st stage", "1st stage", "
Each phase of the i-line 12.16 in K (referred to as "nth stage")
It is assumed that each phase is set to be an O## cylinder.

Thus, when the above relationship is illustrated in a diagram, it is expressed as in the explanatory diagram shown in FIG. Here, FIG. 6 shows that when one pulse is input to the n-th stage, the magnetic head is moved one cylinder at a time, and when one pulse is input to the first stage, the magnetic head is moved four cylinders at a time. It is assumed that when the magnetic head is positioned in the cylinder □, one of the phases ■ to ■ of the second stage winding 16 is excited.

Next, under the above conditions, the operation of the control device 21 is controlled in the seventh mode.
This will be explained with reference to the figures.

It is now assumed that the magnetic head is positioned at the 6## cylinder, the n-th stage ■phase is excited, and the current position of the magnetic head is written in the first storage circuit 22.

In this state, an inward movement signal for moving the magnetic head inward is input from the external device 29 to the second storage circuit 23 via the direction signal line 27.
Assume that the number of step pulses "7308" is inputted via the step pulse signal line 28 and stored. In this case,
The target cylinder is #314.

Then, the arithmetic circuit 24 calculates the phase of the first stage that is connected to the 4 X n## cylinder (n is a positive integer) that is closest to the inner circumferential side from the 6# cylinder, and calculates the ■ phase corresponding to the 8# cylinder. decide. At the same time, the number of pulses necessary to excite the winding 16 of the second stage and rotate it to the 8## cylinder, that is, the number of pulses 2 (=8-6) is stored in the second storage circuit 23. is subtracted from the step pulse number r308J,
The number of stored pulses is assumed to be "306J."On the other hand, for the first storage circuit 22, "2" is added to the stored numerical value "6" to make the stored numerical value "8".

Next, when the above calculation is completed, the arithmetic circuit 241-i' excitation circuit 25 is energized in order to demagnetize the ■ phase of the n-th stage and to perform excitation switching such that the ■ phase of the first stage is energized. Outputs switching command. Based on this command, the excitation circuit 25 connects the power supply circuit 26 and the first stage (2) phase of the stepping motor 1. As a result, the ■phase of the first stage is excited,
Rotating shaft 3 is rotated 1.8 degrees to the position of 8# cylinder. Note that this excitation switching is from the ■ phase of the nth stage to the ■ phase of the first stage.
The rotating shaft 3 rotates by only 1.8 degrees due to excitation switching to the phase, and the number of pulses required for this is one pulse.

Next, the arithmetic circuit 24 determines whether the number of step pulses stored in the second memory circuit 23 is r4J or more - r:, and if it is more than "4", the first stage ■ phase is fully excited. output the signal to the excitation circuit 25, and rotate the rotation N]3 by 3.6°.
Rotate. At the same time, the arithmetic circuit 24 subtracts "4" from the number of stored pulses 1'-306J in the second memory circuit 23, and adds "4" to the first memory circuit 22 to make "12". ” and (-1 remember that the current position of the mother air head is the 12# cylinder.

In this way, the arithmetic circuit 24 repeats the operation of determining whether the number of step pulses in the second memory circuit 23 is "4" or more until the number of step pulses in the memory circuit 23 becomes "3" or less. This continues, and each time the winding 16 of the first stage is sequentially energized.

In the case of the example, the above operation is repeated 76 times, and 8#
The magnetic head is moved inward from the cylinder to the 312# cylinder.

Thus, when the above operation is repeated 76 times, the number of step pulses in the second memory circuit 23 becomes "2", and the numerical value stored in the first memory circuit 22 is l'-312J, which is 1.
In this state, the first stage phase is in the excited state.

Therefore, the arithmetic circuit 24 outputs a command to the excitation circuit 25 to excite the ■phase of the n-th stage, and demagnetizes the ■phase of the first stage. At the same time, the arithmetic circuit 2°4 subtracts "1" from the number of step pulses in the second memory circuit 23, and
1 is added to the numerical value stored in the storage circuit 22. As a result, the rotating shaft 3 becomes 0 due to the excitation of the ■ phase of the nth stage.
．． After rotating by 9 degrees, the magnetic head has reached the 313# cylinder.

Then, the arithmetic circuit 24 operates on path 2 in the second storage circuit 23.
The stored numerical value in i2i is r314J, second storage circuit 2
When the value in 3 becomes "0", the stepping part 1 stops rotating while the n-th stage (2) phase is excited, and the magnetic head remains positioned on the 314# cylinder.

Calculating the number of pulses required for the above series of operations, it is 79 pulses in the example, and the number of pulses in the conventional technology [
Compared to 308J, it is about 1/4, and the access time can be shortened to 1/4.

The embodiments of the present invention are as described above.

The configuration of the ping motor 1 is not limited to that shown in the drawings; for example, the number of phases may be two or three phases, and a variable reluctance motor using a rotor made of toothed soft iron instead of the permanent magnet 4 may be used. It can also be used as a type stepping motor.
Furthermore, the number of teeth can also be selected appropriately.

On the other hand, the operation of the arithmetic circuit 24 constituting the control device 21 is not limited to the above-mentioned operation, and various programs can be selected.For example, in the above-mentioned embodiment, the movement from 61 cylinder to 8# cylinder At this time, the winter memory circuit 22.
23, and from the ■ phase of the nth stage to the ■ phase of the first stage.
Although it has been described that the rotating shaft 3 is rotated by 1.8 degrees by switching the excitation to the
The phase may be sequentially excited, and in this state, the excitation may be switched to the 0th stage ■phase. In this case, the number of pulses is 80.

〔Effect of the invention〕

As described in detail above, the magnetic disk device of the present invention shortens the access time to the target cylinder, speeds up the information processing time even for large-capacity magnetic discs, and has the structure of the device. can be simplified.

[Brief explanation of the drawing]

Figures 1 to 4 show the stepping motor used in this embodiment, and Figure 1 is a vertical sectional view of the stepping motor.
Fig. 2 is a partially cutaway perspective view showing the rotor in Fig. 1, and Fig. 3 is a partially cutaway perspective view showing the rotor and stator in the first stage.
4 is a cross-sectional view in the direction of the IV-IV arrow in FIG. 1 showing the rotor and stator of the second stage; FIG. 5 is a block circuit diagram showing the control device; Figure 6 shows the cylinder number of the magnetic disk and the CJ'i of each stage of the ping motor.
FIG. 7 is an explanatory diagram showing the relationship with l, and FIG. 7 is an explanatory diagram showing the operation of the arithmetic circuit. 1°°° stepping motor, 3... rotating shaft, 5...
・First stage rotor, 6, 8, 11, 15...teeth, 7
... Second stage rotor, 9... First stage stator,
12... @ wire of the first stage, 13... Stator of the second stage, 16... Winding of the second stage, 21... Control device,
22... First memory circuit, 23... Second memory circuit, 24... Arithmetic circuit, 25... Excitation circuit, 27...
- Direction signal line, 28... Step pulse signal line, 29... External device.

Claims (1)

[Claims] In a magnetic disk device, a stepping motor is used as a driving means for positioning a magnetic head with respect to a cylinder of a magnetic disk, and the stepping motor is controlled by a control device. It consists of a multi-stage rotor having the same number of teeth, a multi-stage stator corresponding to each rotor, and a plurality of windings independently wound around the stator of each stage, and one The control device includes a first storage circuit that stores a cylinder number on the magnetic disk corresponding to the current position of the magnetic head, and a second storage circuit that stores the number of step pulses input from an external device. Based on the stored contents from the first and second storage circuits, which winding of which stage of the stepping motor should be excited in order to move the magnetic head from the current position to the target cylinder with the minimum number of excitation pulses. What is claimed is: 1. A magnetic disk drive comprising: an arithmetic circuit that calculates whether or not the arithmetic operation is to be performed; and an excitation circuit that outputs pulses to each winding of each stage of the stepping motor according to the calculation result of the arithmetic circuit.