JPH02289980A - Runaway protection device for magnetic disk device - Google Patents

Abstract

PURPOSE:To make magnetic heads collide against a mechanical stopper at a slower speed than in a runaway state and to suppress shocks to the magnetic heads small by supplying a deceleration current to motors for magnetic head movement according to the detection signal of a non-data-area detecting circuit. CONSTITUTION:This device is provided with the non-data-area detecting circuit 12 which detects a servo head reading position information indicating non-data areas on a magnetic disk 1 and a summing amplifier 15 which supplies the deceleration currents to the motors 5 and 6 for moving the magnetic heads 2 and 3. In this case, when the servo head 3 enters a non-data area and reads position information indicating the area, the non-data area is detected and the motors 5 and 6 for magnetic head movement are fed with the deceleration current for a certain limited time according to the detection signal. Consequently, the magnetic heads 2 and 3 collide against the mechanical stopper 7 after being reduced in speed and thus prevented from running away, thereby suppressing the shocks to the magnetic heads small.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a runaway protection device that protects a magnetic head from running away when a magnetic disk device operates abnormally.

[Prior Art] FIG. 6 is a block diagram showing a conventional runaway protection device for a magnetic disk drive disclosed in, for example, Japanese Patent Laid-Open No. 58-139371. In the figure, (1) is a magnetic disk,
(2) is a data head that reads and writes data from the data surface of the magnetic disk (1); (3) is a servo head that reads head position information from the servo surface of the magnetic head (1);
) is a positioner that mechanically holds the data head (2), servo head (3), etc.; (5) . (6) is the coil and magnetic circuit that constitute the moving motor, (7) is the stopper, (8) is the motor rotation circuit, and (9) is the head position detected from the position information read by the servo head (3). The position detection circuit (10) is a control circuit that controls the drive circuit (8) to flow a drive current to move the head to a desired position at a desired speed in response to the output of the position detection circuit (9). , (11) is a relay that turns on and off the driving current to the control circuit (8), (12) is a non-data area detection circuit, (
13) is a relay drive circuit.

Next, the runaway protection operation will be explained with reference to FIG. During normal operation of the magnetic disk device, the servo head (3) is located on the data area (1a) of the servo surface of the magnetic disk (1), position information is read from that area, and the position detection circuit (9) The head position is detected by the control circuit (8), and a motor current corresponding to the head position is created by the control circuit (8), and is supplied to the motive circuit (8) via the relay (11), and the coil ( 5) and the magnetic circuit (6), the positioner (4) and head (2)
, (3) are called to the desired position at the desired speed. now,
Due to some trouble, the servo head (3) went out of control.
When it leaves the data area (1a) and reaches position A, which is the boundary with the non-data area (1b), the position detection circuit (9) and the non-data area detection circuit (12) use the read position information. Data area detection is performed and the relay (11) is disconnected by the relay swing circuit (13). When the relay (11) is disconnected, the motor current to the shame circuit (8) becomes O, and the positioner (4) continues to move in the direction of the arrow at the speed at position A where the relay was disconnected due to inertia, and stops at the stopper (7) at position B. ) and stops by colliding with

[Problem to be Solved by the Invention] Conventional runaway protection devices for magnetic disk drives are configured as described above, so that when runaway occurs, the positioner collides with the mechanical stopper at a very high speed, resulting in damage to the magnetic disk drive. There is a problem in that a large impact is applied to the head, which may damage the magnetic head or magnetic disk depending on the situation.

This invention was made in order to solve the above-mentioned problems, and is to provide a runaway protection mechanism that prevents the machine from colliding with the mechanical stopper only at a slower speed even if runaway occurs. With the goal.

[Means for Solving the Problems] A runaway protection device for a magnetic disk drive according to the present invention uses a detection signal from a non-data area detection circuit that detects reading of positional information indicating a non-data area of a magnetic disk of a servo head. A summing amplifier is provided to apply a deceleration current to the motor for moving the magnetic head accordingly.

A runaway protection device for a magnetic disk drive according to another aspect of the present invention is a non-data area detection device that divides a non-data area into a plurality of parts and detects reading of positional information indicating each of the divided non-data areas by a servo head. A waveform generating circuit is provided which applies a signal to the summing amplifier to cause the magnetic head moving motor to energize the magnetic head moving motor with a different deceleration current in accordance with the detection signal of the circuit.

[Function] In the runaway protection of the magnetic disk device according to the present invention, when the servo head enters the non-data area and position information indicating this is read out, the non-data area is detected, and in response to the detection signal, A deceleration current is applied to the magnetic head moving motor for a limited period of time, so that the speed of the magnetic head decreases and then collides with a mechanical stopper to prevent runaway.

In a runaway protection device for a magnetic disk drive according to another aspect of the present invention, a servo head enters a non-data area divided into a plurality of areas, and a different deceleration current is applied to the magnetic disk head in accordance with position information read from each non-data area. By energizing the moving motor, the magnetic head stops more smoothly.

[Example 1] An example of the present invention will be described below with reference to the drawings. 1st
The figure is a block diagram showing one embodiment of the present invention, and FIG. 2 is an explanatory diagram of its operation. In the figure, (1) is a magnetic disk, (2) is a data head, (3) is a servo head, and (4) is a data head.
) is the positioner, (5) and (6) are the coils and magnetic circuits that constitute the moving motor, (7) is the stopper, (
8) is the motor perturbation circuit, (9) is the position detection circuit, and (10) is the motor perturbation circuit.
) is a control circuit, (11) is a relay, (12) is a non-data area detection circuit, (13) is a relay drive circuit, which is the same as the conventional example, and (14) is a non-data area detection circuit. (12) A waveform generation circuit consisting of a one-shot multivibrator, for example, which outputs a square wave signal that rises simultaneously with detection and falls after a predetermined time; (15) is a waveform generation circuit that adds signals from the control circuit (10); (14)
The addition amplifier (16) is a delay circuit that delays the detection signal from the non-data area detection circuit (12) by a predetermined time and applies it to the relay drive circuit (13).

Next, the runaway protection operation will be explained with reference to FIG. The operation of the magnetic disk device during normal operation is the same as that of the conventional example, so a description thereof will be omitted. Now, if the servo head (3) goes out of control due to some trouble, the non-data area detection circuit (l2) detects the non-data area as in the conventional example, but this detection signal generates a square wave with a predetermined length of time. A summing amplifier (15
) is added 71? Ru. As a result, a deceleration current flows through the coil (5) for a certain period of time, and the speed of the positioner (4) is decelerated.

After that, the delay circuit (14) activates the relay drive circuit (10) which has been in a waiting state, disconnects the relay (11), and the servo head (3) moves to the position B at the positioner (
4) collides with the stopper (7) and stops.

In the above embodiment, the coil (5) is decelerated and energized with a square wave, but a triangular wave or the like may also be used. Also, although there is only one non-data area, there are multiple areas in which different position signals are recorded depending on the position, and more fine-grained control can be performed, such as by generating different deceleration signals depending on the area. You can also do that.

FIG. 3 is a block diagram showing the embodiment in this case, FIG. 4 is a block diagram showing the schematic configuration of the waveform generation circuit,
FIG. 5 is an explanatory diagram of the operation. That is, in this embodiment, as shown in FIG. 5, the non-data area (1b) on the servo surface of the magnetic disk (1) is divided into two areas: non-data area I (lb■) and non-data area II (lb2). It is divided. In FIG. 3, (12a) is this non-data area I.
(12b) is a non-data area I detection circuit that detects position information read from (lb1), and (12b) is a non-data area II detection circuit.
The non-data area ■ detection circuit (14a) detects the position information read from the non-data area ■ detection circuit (12a). a first waveform generation circuit that outputs;
(14b) is a first waveform generating circuit (
14a) is a second waveform generating circuit that outputs a slope signal that rises with a larger slope than the slope signal; (17) is an adder circuit that adds the output slope signals of both circuits (14a) and (14b); It is similar to FIG. In Figure 4, (
18) is a track pulse counter that counts the number of tracks read by the servo head (3) from the non-data areas (lb1) and (lb2); A digital-to-analog converter (hereinafter referred to as a D/A converter) (20) is an integrator that integrates the output voltage of this D/A converter (19).

-91 Note that the output voltage value for each count of the D/A converter (19) is larger in the second waveform generation circuit (14b) than in the first waveform generation circuit (14a).

Next, the operation will be explained with reference to FIG. If the servo head (3) goes out of control due to some kind of trouble, the non-data area I (lb1) is first detected by the non-data area I detection circuit (12a), and the track pulse is counted by the first waveform generation circuit (14a). By performing D/A conversion and integration, a ramp voltage with a predetermined slope is obtained, which is added to the current motor sleep signal (VCM [motion signal]) in the summing amplifier (15), and the coil (5) is A deceleration current that increases with a predetermined slope flows, and the speed of the positioner (4) is decelerated. Then, the servo head (3) enters non-data area n (lb2) at position B.
The detection circuit (12b) detects this, and the second waveform generation circuit (14b) obtains a slope voltage with a steeper slope than the first waveform generation circuit (14a), and a correspondingly larger slope by an angle θ. The increasing deceleration current flows through the coil (5
), and the positioner (4) is rapidly decelerated. After that, the delay circuit (I4) activates the relay drive circuit (10) that has been in a waiting state, disconnects the relay (11), and the servo head (3) is in the C position and the positioner (4)
collides with the stopper (7) at low speed and stops.

In this embodiment, two non-data areas, two non-data area detection circuits, and two waveform generation circuits are provided, but the number may be three or more. On the other hand, even if there is only one non-data area, one non-data area detection circuit, and one waveform generation circuit, by making the number of track pulses per track in each non-data area different, the deceleration current will be different for each non-data area. can be energized to the motor for moving the magnetic head.

[Effects of the Invention] As described above, according to the present invention, since the deceleration current of the magnetic head is caused to flow by the detection signal of the non-data area, the magnetic head collides with the mechanical stopper at a slower speed in the event of runaway. The applied impact can be suppressed to a small level, and a more reliable device can be obtained. In addition, the non-data area is divided into multiple areas, and by reading position information from these areas, different deceleration currents are applied to the magnetic eight I~
Since the moving motor is energized, the positioner can be stopped smoothly, and the impact exerted on the magnetic head can be further suppressed.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention, and FIG.
3 is a block diagram showing another embodiment of the present invention, FIG. 4 is a block diagram showing a schematic configuration of the waveform generation circuit in this embodiment, and FIG. 5 is a diagram illustrating its operation. FIG. 6 is a block diagram showing a conventional runaway protection device, and FIG. 7 is an explanatory diagram of its operation. In the figure, (1) is a magnetic disk, (1a) is a data area, (1b) is a non-data area, (ib,) is a non-data area, (1b,) is a non-data area, and (2) is a non-data area. Data head, (3) is servo head, (4) is positioner,
(5) is a motor for moving the magnetic head (coil), (6) is a motor for moving the magnetic head (magnetic circuit), (7) is a stopper, (8) is a motor rotation circuit, (9) is a position detection circuit,
(1.0) is a control circuit, (11) is a relay, (12) is a non-data area detection circuit, (12a) is a non-data area I detection circuit, (1.2b) is a non-data area II detection circuit, ( 13) is a relay drive circuit, (14) is a waveform generation circuit, (14a) is a first waveform generation circuit, (14b) is a second waveform generation circuit, (]5 is a summing amplifier, and (16) is a delay circuit. It is. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) A magnetic disk having a data area where positional information indicating the data area is recorded and a non-data area where positional information indicating the non-data area is recorded, and a servo head that reads the positional information of this magnetic disk. , a magnetic disk drive comprising a magnetic head moving motor for moving a magnetic head including the servo head, and a drive circuit for driving and controlling the magnetic head moving motor, the non-data area of the magnetic disk of the servo head; runaway of a magnetic disk device, characterized in that it is provided with a non-data area detection circuit for detecting readout of positional information indicating the position information, and a summing amplifier for energizing a deceleration current to the magnetic head moving motor in response to a detection signal from the circuit; Protective device. (2) The non-data area is divided into multiple parts, and different deceleration currents are applied to each magnetic area in response to the detection signal of the non-data area detection circuit that detects the reading of position information by the servo head indicating each of the divided non-data areas. 2. A runaway protection device for a magnetic disk drive according to claim 1, further comprising a waveform generating circuit for applying a signal for energizing a head moving motor to a summing amplifier.