JPH06309777A - Index generating mechanism for disk device and index signal generating circuit - Google Patents

Abstract

PURPOSE:To prevent the malfunction of a disk device and to increase the reliability of the disk device more by inhibiting the generation of an index signal for constant time after the generation of the index signal. CONSTITUTION:A timer T13 starts when the output d11 of a flip-flop F11 goes to Low and resets the flip-flop F11 compulsively when the output remains in the Low for a specified time. In such a case, the width of the output of the flip-flop is several m sec.s at most at the time of a normal operation, the time of the timer T 13 is adjusted so that the timer is not operated within this time. Thus, even when plural signals are generated from a timer T11 due to the malfunction of the circuit, the timer T11 is brought back to a normal operation since the timer T13 resets the flip-flop F11 during the time when timer T12 is covering the timer T11 so that plural signals are not outputted to the outside as an index signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to prevention of malfunction of an index signal of a disk device.

[0002]

2. Description of the Related Art Conventional index detection is based on actual fairness 1-
No. 32209, and FIGS. 3, 4, 5, and 6.
Shown in. 3 and 4 are plan views of the index detector, FIGS. 5 and 6 are conventional index timing charts, and FIG. 6 is a conventional index generation circuit. In FIG.
A single pole magnetized index magnet 2 is attached to a rotating body 1 that rotates integrally with a spindle, and a magnetic flux generated by the index magnet 2 penetrates through the coil 3 by a coil 3 that is fixed facing the index magnet 2. As a result, a back electromotive force is generated in the coil 3 and this is detected. At this time, the index magnet 2 rotates in the direction of arrow 5 in the figure.

However, a single-pole N-pole index magnet 2 is attached to a rotor 1 made of an iron plate, and a coil 3 is attached.
In the case of attempting to detect by the method, since the index magnet 2 is attached to the rotating body 1, the rotating body 1 becomes a magnetic circuit, and the S pole is generated before and after the rotating direction of the index magnet 2. Therefore, the N pole should originally approach and then move away, so that a positive voltage and a negative voltage should be generated in the coil 3, but in reality, a weak S pole approaches and then moves away. Next, the N pole approaches and moves away, and the weaker S pole approaches and moves away. This is a problem caused by passing through the air easily, unlike the fact that the magnetic field lines move only in a good conductor like electricity, and is an unavoidable phenomenon.

Further, as shown in FIG. 4, the magnetic lines of force of the index magnet 21 magnetized in two poles are detected by the magnetic detection element 4.
In the example detected by, a weak N pole is generated in front of the rotation direction 5 of the index magnet 21 provided in the rotating body 1, and then the S pole and N pole of the index magnet 21 come,
Further, the structure is such that a weak S pole is generated behind the index magnet 21.

As shown in FIG. 5a, the voltage generated from these detecting means is such that first a weak negative voltage is generated, then a positive voltage is generated by the magnetic poles of the index magnets 2 and 21, and then the same. A negative voltage is generated by the magnetic poles of the index magnets 2 and 21. Further, a weak voltage in the positive direction is generated by the magnetic poles behind the index magnets 2 and 21. (Note that FIG.
6A shows the output of the amplifier circuit AM1 in FIG. 6 which will be described later, but it is used for the sake of convenience because it shows the direction of the voltage although the magnitude of the voltage is different. ) At this time, if the last weak positive voltage exceeds the comparison voltage e1 of the comparator circuit shown in FIG. 6, the circuit malfunctions, so that the comparison voltage e1 changes from the first positive voltage of FIG. It was set to the middle position of the voltage to prevent malfunction of the circuit.

This index generation circuit is shown in FIG. The signal generated by the detection means is amplified by the amplifier circuit AM1. FIG. 5 shows the output voltage waveform a after the amplifier circuit AM1. After that, the output of the amplifier circuit AM1 is compared and detected by the comparator circuit, but the comparator CO1 is offset by the comparison voltage e1. The comparison voltage e2 of the comparator C2 is set to approximately 0V. And each comparator CO
Outputs of 1 and CO2 are flip-flops F1 for output control
Are connected to set (S) and reset (R). A timer T1 is connected to the output of the flip-flop F1. The operation of this circuit will be described below.

In the timing chart of FIG. 5, time elapses from left to right. As described above, in FIG. 6, the signal applied from the detecting means to the amplifier circuit AM1 is amplified by the amplifier circuit AM1 and shows the waveform of a. (The small letters ae in FIG. 6 correspond to ae in FIG. 5.) First, when the output of the amplifier circuit AM1 is almost 0, the output c of the comparator CO2 is indefinite. This is the output c
Is not constant in either High or Low and changes. The output of the amplifier circuit AM1 changes to negative due to the magnetic flux in the front direction of rotation of the index magnets 2 and 21. At this time, the output c of the comparator CO2 is Low
However, no change occurs in the output e of the index generating circuit. Furthermore, the output of the amplifier circuit AM1 changes,
When it becomes almost 0 and further changes to a positive value, the output c of the comparator CO2 becomes High at a point of almost 0 (point of the comparison voltage e2). Next, when the output a of the amplifier circuit AM1 exceeds the comparator voltage e1, the output b of the comparator CO1 changes to Low. The flip-flop F1 is set by this change point b1 and its output d becomes Low.
Changes to.

Further, when the output a of the amplifier circuit AM1 decreases and becomes lower than the comparator voltage e1, the output b of the comparator CO1 changes to High. But,
The flip-flop F1 remains set and its output d does not change. Further, when the output a decreases and becomes almost 0, the output c of the comparator CO2 changes to Low (c1 point), and the flip-flop F1 is reset.
The timer T1 operates from the point where the output of the flip-flop F1 changes to High, and the output becomes Low for a certain period of time. This becomes the output e of the index generation circuit and generates an index.

In this way, the index magnets 2, 21
By resetting near the zero cross c1 at the boundary between the positive signal and the negative signal due to, and using this point as an index signal, the index magnets 2 and 2 depending on the temperature
Even if the intensity of 1 changes, the index position of the zero-cross point does not change only by changing the signal amplitude, and a stable index signal can be obtained against temperature changes. It had a basic configuration.

[0010]

In the above-mentioned prior art,
It is possible to generate a stable index signal with respect to temperature changes, but it is necessary to bring the zero-cross accuracy as close to 0 as possible in order to perform detection as stable as possible with respect to temperature changes. As described above. Further, the comparison voltage e1 of the comparator CO1 is offset in order to separate the positive pole of the index magnet, especially the magnetic pole on the rear side in the rotation direction from the positive voltage of the original magnetic pole of the index magnet. However, when the voltage generated by the rear leakage magnetic pole becomes large, a portion a2 that exceeds the comparison voltage e1 is generated as shown in FIG. 7, the index circuit malfunctions, and the index pulse is generated. There is a problem that a plurality of ex and ey are generated. Of course, the magnetic flux from the index magnet should be as strong as possible and the rear magnetic pole should be weak as much as possible, but when the index magnet becomes stronger, the rear magnetic pole also becomes proportionally stronger, which may cause variations in parts and temperature changes. This separation did not work well and sometimes caused problems.

Further, after the magnetic pole behind the index magnet passes by the above-mentioned malfunction, the output c of the comparator CO2 becomes uncertain, but the variation of the comparison voltage e2 and the output a because the rotor 1 is magnetized. If the voltage does not become 0 and a slight positive voltage remains, the output of the comparator CO2 remains High, the flip-flop F1 cannot be reset, and the index detection circuit operates normally. It could not be guaranteed.

[0012]

In order to solve the above problems, the index generating mechanism of the disk device of the present invention is
In the index signal generation mechanism that detects the rotation of the spindle that drives the recording / playback disc housed in the jacket and generates one signal per rotation, the index signal is generated for a certain period of time after the index signal is generated. Characterized by prohibition.

Further, the index signal generating circuit of the present invention first generates the signal voltage by the index signal detecting means, then generates the signal voltage in the reverse direction, and generates the output at the first rising of the signal voltage. Next, in the index signal generation circuit that decreases the signal and inverts the signal near zero crossing to become the index signal, forcibly outputs the index when the output signal does not invert after a certain time has elapsed after the signal was generated at the first rising edge. It is characterized by inverting the signal.

[0014]

With the index generating mechanism configured as described above, even if two or more indexes are generated due to a malfunction of the index, the generation of the index is prohibited except for the first signal, so that the malfunction of the disk device can be prevented. You can do it. In addition, the index signal generating circuit also configured as described above is reset after a certain period of time even if the flip-flop of the index generating circuit remains set due to the influence of an external magnetic field or magnetization. By using it in combination with the generation mechanism, a more reliable index signal can be obtained.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 shows an index generating circuit according to the present invention. Moreover, FIG.
Shows the timing chart of FIG. The lowercase alphabetic symbols shown in FIG. 1 correspond to those in FIG. The electromotive force generated by the index signal detecting means is amplified by the amplifier circuit AM11. After that, the output a11 of the amplifier circuit AM11 is set to the comparator circuit CO
Although the comparison detection is performed by 11, CO12, the comparison voltage e11 is offset in the comparator CO11. Further, the comparator CO12 has the comparison voltage e12 set to approximately 0V. The outputs b11 and c11 of the comparators CO11 and CO12 are connected to set (S) and reset (R) the flip-flop F11 for output control.

Two timers are connected to the output d11 of the flip-flop F11. The timer T11 changes the output f11 to Low from the moment when the output of the flip-flop F11 changes from Low to High, continues to output Low for a fixed time (t0), and then returns to High. This becomes the output of the index through the gate G11.

Next, the timer T13 is a flip-flop F.
The operation is started when 11 becomes Low, and if the flip-flop F11 remains Low after a fixed time (t2), the output h11 changes and the flip-flop F11 is forcibly reset.

The timer T12 outputs the output f of the timer T11.
It is connected to 11. Timer T11 goes from Low to Hi
When it changes to gh, the operation is started, the index output is kept High for a certain time, and even if the output of the timer T11 becomes Low within that time, the gate G11
Is closed and the index output has a function of maintaining High.

The operation of this circuit will be described below. The spindle that rotates the recording / reproducing disk housed in the jacket is the shaft of the main shaft motor that generates rotational force, and the index that is magnetized to a single pole on the outer periphery of the rotor 1 that is the rotor for generating the torque of the motor. The magnet 2 is attached. As in the conventional index generating mechanism, a detection coil 3 wound around a ferrite core facing the index magnet 2 in order to detect the position of the index magnet 2 is arranged on the substrate, as shown in FIG.
As shown in.

When the index magnet 2 approaches the coil 3, the magnetic flux passing through the coil 3 changes in the direction of increase. Then, an electromotive force is generated in the coil 3 in a direction that prevents the change of the magnetic flux. The electromotive force becomes 0 when the index magnet 2 comes closest to the coil 3. And
When the index magnet 2 moves away, the magnetic flux penetrating the coil 3 changes in a decreasing direction, so that the electromotive force generated in the coil 3 is also reversed. However, the magnetic flux generated from the index magnet 2 is generated not only in the magnetized magnetic poles of the magnet 2 but also in excess of the magnetic poles before and after the rotation direction of the index magnet 2 as described in the related art. FIG. 2 shows the temporal change of the signal of each part of the index generating circuit at this time.

In FIGS. 1 and 2, the voltage generated in the index detector of FIG. 3 is amplified by the amplifier circuit AM11. As long as the index magnet 2 does not approach the coil 3, no electromotive force is generated in the coil 3 and the state of approximately 0 V continues. At this time, when the comparison voltage e12 of the comparator C012 is approximately 0 V, the output is not constant and H
Outputs high and low. In this embodiment, the comparison voltage e1
Since the example in which 2 is slightly shifted to the negative side due to variation is shown, the output c11 of the comparator CO12 remains High. And the comparator CO1
In the case of 1, the comparison voltage is offset by e11, so the output b11 remains High. Next, when the index magnet 2 approaches the coil 3, the output a11 of the amplifier circuit AM11 changes to negative due to the influence of the leakage magnetic pole on the opposite side. In this state, the comparator CO
Only the output c11 of 12 changes to Low, and the flip-flop F11 does not change.

Next, when the index magnet 2 body approaches the coil 3, the output voltage a11 changes to plus. When this voltage crosses the comparison voltage e12, the output c11 of the comparator CO12 changes to High.

Further, when the index magnet 2 approaches the coil 3, the output a1 of the amplifier circuit AM11 is output.
When 1 exceeds the comparison voltage e11 of the comparator CO11, the output of the comparator CO11 changes to Low. Due to this change, the flip-flop F11 is set, and the output d11 of the flip-flop F11 becomes Low.

When the index magnet 2 further approaches the coil 3, the output a11 starts to decrease, and the output becomes 0 at the position where the index magnet 2 and the coil 3 are closest to each other. At this time, when the output a11 becomes equal to or lower than the comparison voltage e12, the output of the comparator CO12 changes to Low and resets the flip-flop F11, so that the timer T11 starts operating and an index signal is generated.

When the index magnet 2 further moves away from the coil 3, the output becomes 0 again. This allows
The output of the comparator CO12 becomes High again.
However, as described in the conventional example, the leakage magnetic flux of the index magnet 2 causes an opposite line of magnetic force to penetrate the coil 3, and the output again becomes the positive side. As long as this output does not exceed the comparison voltage e11, the output b11 of the comparator CO11 does not change, the flip-flop F11 is not set again, and the index signal is generated only once at a normal position. After the signal due to this leakage magnetic flux, the signal becomes near 0, but the comparator CO1
Since the comparison voltage e12 of 2 is slightly offset to the negative, the output of the comparator CO12 remains High.

Actually, as shown in FIG. 2, a case where the output due to the final leakage magnetic flux is large and the index generating circuit malfunctions will be described. Next, when the index magnet 2 approaches the coil 3, the output a11 of the amplifier circuit AM11 changes to negative due to the influence of the leakage magnetic pole on the opposite side. In this state, the output c1 of the comparator CO12
1 is fixed to Low, flip-flop F1
There is no change in 1.

Next, when the main body of the index magnet 2 approaches the coil 3, the output voltage a11 changes to plus. When this voltage crosses the comparison voltage e12, the output c11 of the comparator CO12 changes to High.

Further, when the index magnet 2 approaches the coil 3, the output a1 of the amplifier circuit AM11
When 1 exceeds the comparison voltage e11 of the comparator CO11, the output b11 of the comparator CO11 changes to Low. Due to this change, the flip-flop F11 is set, and the output d11 of the flip-flop F11 becomes L.
become ow.

On the contrary, when the index magnet 2 further approaches the coil 3, the output begins to decrease, and the output becomes 0 at the position where the index magnet 2 and the coil 3 are closest to each other. At this time, when the output a11 becomes equal to or lower than the comparison voltage e12 of the comparator CO12, the output of the converter CO12 changes to Low and resets the flip-flop F11, so that the timer T11 starts operating and an index signal is generated.

When the index magnet 2 is further moved away from the coil 3, the output becomes 0 again. This allows
The output of the comparator CO12 becomes High again.
However, as described in the conventional example, the leakage magnetic flux of the index magnet 2 causes an opposite line of magnetic force to penetrate the coil 3, and the output again becomes the positive side. Up to this point, the operation is the same as the normal operation described above. However, when the output a11 exceeds the comparison voltage e11, the output b of the comparator CO11
11 becomes Low again, and the output d11 of the flip-flop F11 also becomes Low. This allows the timer T11
But the timer T11 has already been activated at this time.
The timer T12 has started to operate from the time when the output f11 of the F1 changes from Low to High for the first time, and the flip-flop F11 operates while the timer T12 is operating.
Output f1 of timer T11 due to change in output d11 of
Even if 1 goes low again, the gate G11 is closed so that the index signal does not go low.

Further, even if the index magnet 2 moves away from the coil 3 and the leakage flux after the index magnet 2 also decreases and the output voltage approaches 0, the variation of the comparison voltage e12 of the comparator CO12 causes the variation of the comparator CO12. The output does not reverse to Low.

In the case of this embodiment, the comparative voltage e12 is slightly negatively offset due to variations, but in the case of magnetic flux detection by a magnetic detecting element described later, the rotating body 1 is slightly magnetized. However, the output voltage does not become 0 and the comparator CO12 does not become Low.

Then, the flip-flop F11 becomes Low.
Is output, and the index output is Lo as well.
It will remain as w. To prevent this, the timer T13 causes the output d11 of the flip-flop F11 to be Lo.
When it reaches w, it starts and when it remains Low for a certain period of time, the flip-flop F11 is forcibly reset. Of course, the timer T13 is started even when the flip-flop F11 is operating normally, but in the normal state, the width of the output of the flip-flop F11 is at most several msec, and the timer T13 does not operate within this time. I have made adjustments.

In this way, even if a plurality of signals are generated from the timer T11 due to a malfunction of the circuit, the timer T12 is
The timer T13 resets the flip-flop F11 while it is covered so that it will not be output to the outside as an index signal, and the normal operation is restored.

Next, the case where the detection of the index magnet is performed by the magnetic detection semiconductor will be described. The magnetic detection element in this case is a Hall element, but a magnetic resistance change element (MR element) can be similarly used.

As shown in FIG. 4, the spindle for rotatably driving the recording / reproducing disc housed in the jacket is the shaft of the main shaft motor for generating the rotational force, and the outer peripheral portion of the rotor 1 which is the rotor for generating the torque of the motor. An index magnet 21 magnetized to have two poles is attached to the. In order to detect the position of the index magnet 21, the Hall element 4 is arranged on the substrate so as to face the index magnet 21.

When the index magnet 21 approaches the hall element 4, the magnetic flux penetrating the hall element 4 increases and the output also increases. Since the index magnet 21 has two poles, when the opposite pole approaches the Hall element 4, the output goes in the opposite direction. Unlike the coil, the Hall element 4 does not output the change in the magnetic flux of the index magnet 21, but outputs an output proportional to the magnetic flux of the index magnet 21. However, the magnetic flux generated from the index magnet 21 is generated by the index magnet 2.
As described in the related art, not only one magnetized magnetic pole, but extra magnetic poles are generated before and after the rotation direction of the index magnet 21. The temporal change of the signal of each part of the index generation circuit at this time is as shown in FIG. 2 similarly to the index generation by the coil.

In FIG. 2, the voltage generated from the Hall element is amplified by the amplifier circuit AM11. If the index magnet 21 does not approach the Hall element 4, the Hall element 4
The output voltage of is kept at about 0V. When the index magnet 21 approaches the hall element 4,
First, the output a11 of the amplifier circuit AM11 changes to negative due to the influence of the leakage magnetic flux in front of the index magnet 21. Next, when the tip magnetic pole of the index magnet 21 approaches the Hall element 4, the output voltage changes to plus. Further, the index magnet 21 is the hall element 4
When approaching to, the output of the Hall element 4 decreases due to the influence of the magnetic pole behind the index magnet 21, and the output of the Hall element 4 becomes negative due to the magnetic pole behind. When the magnetic pole after the index magnet 21 passes through the Hall element 4, the output becomes 0 again. However, as described in the conventional example, the leakage magnetic flux of the index magnet causes an opposite leakage magnetic field line to penetrate the Hall element 4 after the index magnet has passed, and the output again becomes the positive side. As described above, the index generating circuit operates normally because the output of the comparator CO11 does not change unless the output a11 of the amplifier circuit AM11 exceeds the comparison voltage e11. Even when the index generating circuit malfunctions, the operation is the same as that of the coil described above. Since the operation of the circuit is the same as the operation of the index generating circuit by the coil in FIG. 3 described above, the description thereof will be omitted. It is a product that can be prevented from occurring.

In FIG. 1, a timer circuit using a resistor (R) and a capacitor (C) is shown as the timer circuit, but the clock signal is counted due to the recent improvement in circuit integration. It goes without saying that this circuit can be configured without problems even with a timer configuration.

[0040]

As described above, the index generating mechanism and the index signal generating circuit of the disk device according to the present invention, when the magnet is used for detecting the index circuit as described above, electrically causes the malfunction of the circuit due to the leakage flux of the magnet. In addition, it is a product that can obtain a normal index signal even if there is magnetic leakage of the magnet, and can further improve the reliability of the disk device that requires reliability.

[Brief description of drawings]

FIG. 1 is an index generation circuit diagram according to the present invention.

FIG. 2 is an index timing chart according to the present invention.

FIG. 3 is a plan view of an index detector.

FIG. 4 is a plan view of an index detector.

FIG. 5 is an index timing chart during normal operation.

FIG. 6 is a conventional index generation circuit diagram.

FIG. 7 is a conventional index timing chart at the time of malfunction.

[Explanation of symbols]

 AM11 amplifier circuit CO11 comparator CO12 comparator F11 flip-flop T11 timer T12 timer T13 timer G11 gate e11 comparison voltage e12 comparison voltage

Claims (9)

[Claims] 1. An index signal generating mechanism for detecting the rotation of a spindle that rotationally drives a recording / reproducing disc housed in a jacket and generating a signal for each rotation, for a predetermined time after the index signal is generated. An index generation mechanism for a disk device, which is characterized by prohibiting generation of index signals. 2. The index generating mechanism of a disk device according to claim 1, wherein the index generating mechanism is composed of a rotating magnet and a fixed magnetic detecting element. 3. The index generating mechanism of a disk device according to claim 1, wherein the index generating mechanism is composed of a rotating magnet and a fixed coil. 4. The index generating mechanism of a disk device according to claim 2, wherein the magnet is provided on an outer peripheral portion of a rotor of a motor configured as a spindle for rotating and driving the disk. 5. The index generating mechanism of a disk device according to claim 1, wherein the time for inhibiting the generation of the index signal is shorter than the cycle of one rotation of the spindle. 6. The index generating mechanism of a disk device according to claim 1, wherein the timer circuit for inhibiting the generation of the index signal is a delay circuit of a resistor and a capacitor. 7. The index generating mechanism of a disk device according to claim 1, wherein the timer circuit for inhibiting the generation of the index signal is a timer circuit for counting a clock. 8. A signal voltage is generated by the index signal detection means, then a signal voltage in the opposite direction is generated next, an output is generated at the first rising of the signal voltage, and then the signal decreases and near zero crossing. In the index signal generation circuit that inverts the signal and uses it as the index signal, the index output signal is forcibly inverted if the output signal is not inverted after a certain time after the signal is generated at the first rising edge. Index signal generation circuit. 9. A circuit for forcibly inverting the index output signal when the output of the index signal does not return to a normal state after a certain period of time is followed by a circuit for inhibiting the generation of the index signal for a certain period of time after the generation of the index signal. 9. The index signal generation circuit according to claim 1, wherein an unnecessary signal is not output as an index signal.