JPH0158589B2 - - Google Patents

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 windings are arranged opposite to each other with a gap in between, and the one provided on the rotor.
a small piece of magnetic material, a magnetic detector disposed opposite to the small piece through a gap, a mechanism for shaping the outputs of the power generation winding and the magnetic detector into pulse-shaped outputs, and It is characterized by comprising a sector signal generating mechanism that counts and extracts the pulses obtained from the winding at each generation interval of the pulses obtained from the magnetic detector.

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

Figure 1 shows a conventional sector signal generator.
1 is a magnetic desk, 2 is a driving electric motor, 3 is a disc with a slit for generating sector signals directly connected to the motor shaft 5, 4 is an interrupter composed of a light source and a photoelectric converter, 6 is a substrate, and 7 is a magnetic disk. Head 8 is a device for driving the magnetic head 7 in the radial direction.

The magnetic desk 1 is usually formed by coating the surface of a non-magnetic disc with fine magnetic powder, and is directly connected to the motor shaft 5 of the drive motor 2 so that it is rotated by the motor 2 at a constant speed. It's getting old. A magnetic head 7 is disposed on the magnetic material-coated surface of the magnetic disk 1 through an extremely narrow gap. The track recording the information of the concentric circles formed on the magnetic material coated surface of No. 1 is traced. Also, the track on which information is recorded is divided into sectors 1 equally divided in the circumferential direction.
−2, and the location of the information recorded on the magnetic disk is o to p for the number of tracks p.
It is now possible to specify an address using both the numbers up to 1 and the numbers os to s for the number of sectors.

However, these tracks and sectors are not actually delineated by lines on the magnetic coating;
The track boundaries are magnetic head positioners,
Further, the sector is designed to detect a signal generated by a sector signal generating slit disk 3, detect a predetermined address, and record and read information. As shown in FIG.
are provided at equal intervals on the circumference, and one slit 3-2 is provided at a position slightly apart from the slit 3-1 in the radial direction as shown in FIG.
Interrupters 4-1 and 4-2, each consisting of a light source and a photoelectric converter, are provided on the stator side.

When the driving electric motor 2 is rotated at a constant speed, the magnetic disk 1 and the disc 3 with a slit for generating sector signals are generated.
rotate at the same time, and the interrupter 4 outputs a pulse signal as shown in FIG. 1d. That is, the interrupter 4-1 facing the slit 3-1 generates S pulses, the same number as sectors, at equal pitches for one rotation of the disk, and the interrupter 4-2 generates one index pulse for each rotation. Occur. Therefore, if the output of the interrupter 4-1 is added to a counter and the counter is reset by the output of the interrupter 4-2, the contents of the counter will be reset to zero by the index pulse and the next pulse will arrive. When the count reaches s from the pulse generated in the slit 3-1, it 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 pth track by the radial drive device 8 according to the track number p.If the output of the counter becomes n, then the position of the magnetic head 7 is moved to the pth track according to the track number p. When the nth sector of the track is reached, it is cut in half and a write or read signal is sent to the magnetic head by ANDing the command signal and the detection signal, so that information can be written or read at a predetermined location on the magnetic disk. .

However, the slits 3-1 and 3-2 provided on the slit-equipped disk for sector signal generation must have extremely high processing quality, and the concentricity with respect to the motor shaft 5 must also be set with high precision, otherwise the pitch between the sectors will increase. There was a problem that the information exchange with the magnetic disk was inaccurate due to the imbalance, and there was a defect that increased the cost of the sector signal generator.

For example, slit 3-1 when the number of sectors is 45
The pitch accuracy is as high as 8°±0.05°, and both the processing of the slit disc and its installation require the skills of highly skilled workers, which hinders mass production.

The present invention has been made to eliminate such drawbacks, and in the present invention, as shown in FIG. A power generation winding 23 for speed detection is attached to the board 6 facing the rotor 21, and a small magnetic piece 24 is attached to the rotor 21.
A magnetic detector 25 is provided on the substrate 6 opposite to the magnetic detector 4 .

As shown in FIG. 2b, the power generation winding 23 for speed detection is arranged so that the power generation conductor 23-1 is placed on an insulating plate 23-4 at equal pitches in a radial direction, twice the number of sectors of the magnetic desk 1, in the circumferential direction. The radially inner ends and outer ends of adjacent conductor pieces are connected alternately with separate conductor pieces 23-3 and 23-2 to form a continuous winding terminal. Connect to A and B to form. On the surface of the power generation permanent magnet 22 facing the power generation winding 23, as shown in FIG. .

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, inducing voltage in the power generation conductor 23-1 and all the power generation conductors 23-1. Since the induced voltages always have the same polarity, they are all applied in series and outputs are produced at terminals A and B. 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 converted into pulse signals via amplifiers 30, 31 and waveform shaping circuits 32, 33, respectively, as shown in FIG. 2e. That is, as shown in FIG. 3a, the output of the power generation winding 23 becomes an alternating current whose period is one pole pitch of the permanent magnet 22, and this is saturated and amplified by the amplifier 31 to form a rectangular wave as shown in FIG. 3b. At a position where the polarity of this rectangular wave changes from (-) to (+), a pulse signal is generated as shown in FIG. 3c. As a result, during one rotation of the rotor 21, half the number of pulses as the number of power generation conductors 23-1, that is, the same number of pulses as the number of sectors 1-2 of the magnetic disk 1 are generated.

On the other hand, since the magnetic detector 25 generates one pulse as shown in FIG. 2d every time the rotor 21 makes one rotation, this pulse is used as an 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 when the index pulse arrives, and when counting starts from the next pulse, the magnetic desk 1
The contents of the counter can be used as a sector signal for the magnetic disk 1 because the counter is counted up to the same number as sectors 1-2 and then reset.

As a specific example of the configuration of the power generation winding 23, an insulating board is used as a printed wiring board, and the power generation conductor 23-1 of the power generation winding 23 is constructed on this using a 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. Furthermore, the pitch accuracy of the sector signal is maintained by the accuracy of the equal pitch of the power generation conductor 23-1 of the power generation winding 23, the magnetization accuracy of the power generation permanent magnet 22, and the degree of eccentricity between the two.
Since all of the power generation conductors 23-1 of the power generation winding 23 are connected in series, the period of one cycle of the generated alternating current is the average value of all the windings, and may vary depending on the pitch between the individual conductors or the magnetization pitch of the magnet. Even if there is an error, this is averaged out and does not appear as an error, so
There is an advantage that sufficient accuracy can be obtained even if the power generation winding is constructed using printed wiring techniques.

In addition, with conventional equipment, when the number of sectors is 45, the pitch accuracy between sectors must be 8° ± 0.05°.
In embodiments of the present invention, an accuracy of 8°±0.01° can be easily achieved.

[Brief explanation of drawings]

Figure 1a is an explanatory diagram of the fixed magnetic desk device, Figure 1b is a detailed diagram of the magnetic desk attached to this equipment, Figure 1c is a detailed diagram of the sector signal generator, and Figure 1e is the sector signal. An explanatory diagram of the slit of the disc with a generating slit, FIG. 1d is an explanatory diagram of the pulse signal,
FIG. 2a is a block diagram of a magnetic disk drive device equipped with a sector signal generator according to the present invention, FIG. 2b is a detailed diagram of a power generation winding for speed detection, and FIG. 2c is a detailed diagram of a permanent magnet for speed detection. FIG. 2d is a waveform diagram of a detection signal, FIG. 2e is a pulse signal generation circuit diagram, and FIGS. 3a to 3c are illustrations of output waveforms of the power generation windings, respectively. 1...Magnetic desk, 2...Drive motor, 3...
...Disk, 4...Interrupter, 5...Motor shaft, 6...Substrate, 7...Magnetic head, 8...Radial drive device, 21...Rotor, 22...Permanent magnet, 23... Power generation winding, 23-1...Conductor for power generation, 23-2, 23-3...Conductor piece, 23-4...
...Insulating plate, 24...Small piece, 25...Magnetic detector,
30, 31...Amplifier, 32, 33...Waveform shaping circuit.

Claims (1)

[Claims] 1 A permanent magnet for speed detection that is magnetized alternately with N and S magnets at equal intervals in the circumferential direction, which is attached to the rotor of a magnetic desk drive electric motor, and a power generation winding that is arranged opposite to the permanent magnet with an air gap interposed therebetween. and 1 provided on the rotor.
a small piece of magnetic material, a magnetic detector disposed opposite to the small piece through a gap, a mechanism that shapes the waveforms of the outputs of the power generation winding and the magnetic detector to produce pulse-like outputs, and A sector signal generating device for a magnetic disk, comprising a sector signal generating mechanism that counts and extracts the pulses obtained from the winding at every generation interval of the pulses obtained from the magnetic detector.