JPS58102377A - Sector signal generator for magnetic disk - Google Patents

Abstract

PURPOSE:To improve pitch precision between sectors and to allow mass-production at low cost by equipping one small piece of magnetic material and a permanent magnet for speed detection to the rotor of a motor for driving, and fitting power generating winding opposite to them. CONSTITUTION:When a motor for driving is rotated at a specific speed, the magnetic flux of a magnet linked with power generating winding 23 varies to induce a voltage at an power generating conductor 23-1, obtaining outputs at terminals A and B. The induced voltage is an AC voltage and its period is a half as great as the number of power generating conductors 23-1. Every time a small piece 24 equipped to the outer circumference of a rotor 2 faces a magnetic detector 25, the detector 25 generates an output signal. Outputs from said winding 23 and detector 25 are converted into pulse signals through amplifiers 30 and 31 and waveform shaping circuits 32 and 33 and while the rotor 21 makes one turn, the winding 23 generates pulses as many as sectors of a magnetic disk 1 and the detector 25 generates one pulse.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sector signal generator for a fixed magnetic disk fixed to a drive motor.

A sector signal generator for a magnetic desk according to the present invention includes a speed detection permanent magnet that is attached to the rotor of a magnetic desk drive motor and is magnetized with N and S magnets alternately at equal intervals in the circumferential direction, and The power generation winding consists of a power generation winding arranged opposite to each other with a gap in between, a small piece of magnetic material provided on the rotor, and a magnetic detector arranged opposite to the small piece with a gap in between. A plurality of power generation conductors interlinking with the magnetic flux of the permanent magnet are arranged at equal intervals, and one end and the other end of the adjacent power generation conductors are alternately connected to form a continuous winding. shall be.

The present invention will be explained in detail below with reference to the drawings.

Fig. 1 shows a conventional sector signal generating device, where 1 is a magnetic disk, 2 is a driving electric motor, 3 is a sector signal generating slit directly connected to the motor shaft 5, a disc with a groove, and 4 is a light source and photoelectric conversion. 6 is a substrate, 7 is an interlayer consisting of a
8 is a device for driving the magnetic head 7 in the radial direction.

[Magnetic desk] is usually formed by coating the surface of a non-magnetic disc with fine magnetic powder, and is used to attach the motor shaft 5 of the drive motor 2.
The electric motor 2 rotates at a constant speed. A magnetic head 7 is disposed on the magnetic material-coated surface of the magnetic disk 1 through an extremely narrow gap. Concentric tracks on which information is recorded are traced on the surface coated with magnetic material. Also, the tracks on which information is recorded are divided into sectors 1-2, which are equally divided in the circumferential direction, and the location of the information recorded on the magnetic disk is determined by the number from op to track number p and the number of sectors B. The address can be specified using both numbers 0 to B.

However, these tracks and sectors are not actually divided by lines on the magnetic coating, but the boundaries of the tracks are defined by a magnetic head positioning device, and the sectors are defined by a disc 3 with a slit for generating sector signals. By detecting the signal generated by the controller, a predetermined address is detected, and information is recorded and read. This disc 3 with slits for generating sector signals has a magnetic disk 1 as shown in FIG. 1(c).
The same number of slits 3-1i as the number of sectors 1-2 provided in
One slit 3-2 is provided at equal intervals on the circumference, and at a position slightly distant from the slit 3-1 in the radial direction, as shown in FIG. 1 (C'). 4-2i is provided on the stator side.

When the driving electric motor 2 is rotated at a constant speed, the magnetic desk 1
and the disk 3 with slits for sector signal generation rotate at the same time, and the interrupter 4 outputs a pulse signal as shown in FIG. 1(d). That is, the interrupter 4-1, which faces the slit 3-1, generates eight pulses, the same number of which are the same as the seftat, at equal pitches per rotation of the disk, and the interrupter 4-2 generates one index pulse per rotation. Occur. So this interrupter 4-
If the output of 1 is added to a counter and the counter is reset by the output of interrupter 4-2, the contents of the counter will be reset to zero by the index pulse and will be generated at the next arriving slit 3-1. When counting from the pulse to 8, the counter is reset by the index pulse, so that the contents of the counter indicate the sector number.

Therefore, in order to trace a specified address, the position of the magnetic head 7 is moved to the p-th track by the radial drive device 8 according to the track number p, and when the output of the counter becomes n, the position of the magnetic head 7 is moved to the p-th track of the specified p-th track. If it is determined that this has been reached and a write or read signal is sent to the magnetic head by ANDing the command signal and the detection signal, information can be written or read from a predetermined location on the magnetic disk.

However, the machining precision of the slits 3-1 and 3-2 provided in this disk with slits for generating sector signals must be extremely high, and the concentricity with respect to the motor shaft 5 must also be set with high precision. There is a problem that the pinch is unequal and the exchange of information with the magnetic desk becomes inaccurate.
There was a defect that increased the cost of the sector signal generator.

For example, when the number of sectors is 45, the pitch i degree of slit 3-1 is highly accurate at 8° ± 0.05°, and both the processing of the slit disk and its installation require the skills of highly skilled people, and mass production is required. is hindering.

Does the present invention have such drawbacks? In the present invention, as shown in FIG. A power generation winding 23 for speed detection is attached to the rotor 21, a small magnetic piece 24 is attached to the rotor 21, and a magnetic detector 25 is mounted on the board 6 opposite to this small piece 24.
Provided for.

As shown in FIG. 2(b), the power generation winding 23 for speed detection has a power generation conductor 23-1 on an insulating plate 23-4.
The number of sectors is twice as many as the number of sectors. 23-3 and 23-2 are alternately connected to form a continuous winding and connected to terminals A and H. As shown in FIG. 2(c), the surface V of the power generation permanent magnet 22 facing the power generation winding 23 has the same number of magnets as the power generation conductor 23-1 alternately with KN@ and S lines at an equal pitch. Magnetize.

In FIG. 2, when the drive motor 2 is rotated at a constant speed, the magnetic flux of the magnet interlinking with the power generation winding 23 changes, and a total voltage is induced in the power generation conductor 23-1. Since the induced voltages always have the same polarity, they are all applied in series to produce a BVC output at the terminal. The direction of the interlinking magnetic flux changes every time the polarity of the magnet changes, and the induced voltage is an alternating voltage, and the period of this alternating current corresponds to 1/2 of the number of power generation conductors 23-1. Further, each time the rotor 21 rotates and the small piece 24 attached to the outer periphery of the rotor 21 faces the magnetic detector 25, an output signal appears from the magnetic detector 25.

The outputs of the power generation winding 23 and the magnetic detector 25 are outputted to amplifiers 30, 31 and waveform shaping circuits 32, 31, 32, 31, 32, 31, 31, 31, 31, 31, 31, 31, 31, 31, 32, 32, 32, 31, 32, 31, 32, 32, 32, 31, 32, 31, 32, 31, 31, 31, 31, 31,3,3, 4, and 3, respectively, as shown in FIG. 2(,).
33 into a pulse signal. In other words, Figure 3 (,
), the output of the power generation winding 23 is 1 of the permanent magnet 22.
An alternating current with a period of pole pitch is saturated and amplified by the amplifier 31 to form a rectangular wave as shown in Fig. 3(b), and at the position where the polarity of this rectangular wave changes from ←) to (g). Figure 3 (
A pulse signal is generated as shown in C). As a result, during one rotation of the rotor 21, the number of pulses is 1/2 of the number of power generation conductors 23-1, that is, sector 1- of magnetic test 1.
The same number of pulses as 2 are generated.

On the other hand, since one pulse is generated from the magnetic detector 25 as shown in FIG. 2(d) every time the rotor 21 rotates once, this pulse is used as the total index pulse. If the output pulse of the power generation winding 23 is input to a counter and the counter is reset by the index pulse, the counter is reset by the arrival of the index pulse,
Counting starts from the next pulse and is reset after counting to the same number as the magnetic disk 10 sectors 1-2, so the contents of the counter can be used as signals for the magnetic disk 10 sectors.

As a specific example of the configuration of the power generation winding 23, the insulating board is a printed wiring board, and the power generation winding 230 is connected to the power generation conductor 23-1.
1 (constructed using printed wiring technique. In this way, the accuracy of the equal pitch of the power generation conductor 23-1 is high, and there is an advantage that mass production can be performed at low cost. Also, the pinch accuracy of the sector signal is Power generation conductor 23-1 of power generation winding 23
This is maintained by the accuracy of the equal-distribution pinch, the magnetization accuracy of the power generation permanent magnet 22, and the degree of eccentricity between the two, but all of the power generation conductors 23-1 of the power generation winding 23 are connected in series. The period of one cycle of alternating current generated by the current is the average value of all the windings, and even if there is some error in the pitch between individual conductors or the magnetization pinch of the magnet, this is averaged out and does not appear as an error, so the power generation Even if the windings are constructed using printed wiring techniques, there is the advantage that sufficient accuracy can be obtained.

In the conventional device, when the number of sectors is 45, the pitch accuracy between sectors must be 8°±0.05°, but in the embodiment of the present invention, an accuracy of 8°±0.010 can be easily achieved.

[Brief explanation of the drawing]

Figure 1 (,) is an explanatory diagram of a fixed magnetic desk device, and Figure 1 (b) is a magnetic desk attached to this device. Detailed view, 1st
Figures (,) are detailed diagrams of the sector signal generation section, and Figure 1 (C'
) is an explanatory diagram of the slits in the disk with slits for sector signal generation, Fig. 1 (d) is an explanatory diagram of the pulse signal, and Fig. 2 (,)
2 is a block diagram of a magnetic desk drive device equipped with a sector signal generator according to the present invention, FIG. 2(b) is a detailed diagram of a power generation winding for speed detection, and FIG. 2(c) is a detailed diagram of a permanent magnet for speed detection. Figure 2(d) is a waveform diagram of the detection signal, Figure 2(,) is a pulse signal generation circuit diagram, and Figures 3(a) to 3(e) are explanations of the output waveforms of the power generation windings. It is a diagram. 1...Magnetic desk, 2...Drive motor, 3...
Disc, 4... Interrack, 5... Motor shaft, 6
... Substrate, 7... Magnetism-\rad, 8... Radial drive device, 21... [1st trochanter, 22... Permanent magnet,
23... Power generation winding, 23-1... Power generation conductor, 23
-2.23-3...Conductor piece, 23-4...Insulating plate,
24...Small piece, 25...Magnetic detector, 30.31.
...Amplifier, 32゜33...Waveform shaping circuit. Agent Patent attorney Makoto Sawaki - Procedural amendment (method) April 27, 1980 Commissioner of the Japan Patent Office Shima 1) Haruki Tono1, Indication of case Patent application No. 1982-200109 No.2, Title of invention Magnetic desk Sector signal generator 3, relationship with the amended person case Patent applicant name Nippon Servo Co., Ltd. 4 Agent name (6298) Yuriju Makoto Sawaki
-5. Amendment Order [1] March 30, 1980 6. Subject of amendment (1) Column for detailed explanation of the invention in the specification (2) Column for brief explanation of the same drawing (3) Drawings (Figure 1) 7. Contents of amendment <2> Change r(c')J on page 4, line 6 of the specification to "(
e)”. (2) r(e')J on page 10, line 11 of the specification is r(
e) Correct it as J. (3) As per attached sheet

Claims (1)

[Claims] (1) Permanent magnets for speed detection, which are alternately magnetized with N and S magnets at equal intervals in the circumferential direction, are attached to the rotor of the electric motor for driving the magnetic desk, and are arranged opposite to the permanent magnets with an air gap in between. It consists of a power generation winding, a small piece of magnetic material provided on the rotor, and a magnetic detector placed opposite the small piece with a gap in between, and the power generation winding interlinks with the magnetic flux of the permanent magnet. A sector signal of a magnetic desk characterized in that a plurality of power generation conductors are arranged at equal intervals, and one end and the other end of the power generation conductors that are adjacent to each other are connected alternately to form a continuous winding. Generator.