JPS6019586B2 - Magnetic head feeding device using pulse motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a magnetic head feeding device using a pulse motor for moving and positioning a magnetic head to a predetermined track position on a magnetic medium.

In storage devices such as magnetic drums or magnetic disks, it is necessary to move a magnetic head to a predetermined track position on a magnetic medium to write or read information.

For example, in a floppy disk device, as shown in FIG. 1, a floppy disk having tracks arranged concentrically is used as a magnetic medium, and is inserted into a spindle 2 and rotated.

The magnetic head 3 is connected to a write circuit or a write circuit (not shown), is supported by a carriage 4, and is moved radially over the floppy disk by the rotational movement of a lead screw 5.

The lead screw 5 is rotated by a pulse motor 7 via a coupling part 6 consisting of a gear and a joint, and the pulse motor 7 receives an output signal ◇,, ma,
，? 2,? 2 is excited and step-driven via the drive circuit 9. For example, in the case of two-phase excitation, as shown in the timing chart shown in FIG. 2, when signal a is input to the clock generation circuit 8 as a step command, n pulses (n is a positive integer) are generated for each pulse. A signal with?
,,J,,? 2, J2 are switched and generated according to the order determined by signal b. Signal. On the other hand, signal J2 is delayed by 900 phase, and signal ◇,,? 2 What?
，，? 2 are polarity inverted signals, so signal ``G'' is delayed by 180 degrees in phase with respect to signal ``low'', and signal ``low'' 2 is signal ? , the phase is delayed by 270o. signal? ,,0. , 〇2, gu2 is ○,, 2 → ◇.・〇2→
41.J2 →J...J2 →.・When the signals are switched and repeatedly generated in the order of 02, the pulse motor 7 is driven by n steps for each I cycle of pulses of each signal, rotating the lead screw 5 via the coupling part 6 and rotating the carriage 4. The magnetic head 3 is moved in the radial direction on the floppy disk 1 by one track. A predetermined number of tracks can be sent depending on the number of pulses of signal a. Also, if the above case is to send the magnetic head inward, then
By changing the command direction of signal b, the order in which signals ◇, , CI, and 2 are generated from the clock generation circuit 8 can be changed by changing the command direction of signal b.・J2 →g.・gu2 →gu・●su2→◇・・J
2→◇． .g2, the rotation direction of the pulse motor 7 is reversed, and the magnetic head 3 can be moved toward the outer circumference of the floppy disk 1. In this way, when a pulse motor is used to position the magnetic head on a predetermined track on a magnetic medium, this is done by driving the pulse motor in multiple steps per track, moving from the previous track to the next track. was moving to.

However, magnetic media such as floppy disks made from flexible Mylar have a much larger temperature coefficient than the lead screw that sends the magnetic head, and even though the magnetic media expands and contracts with temperature, Since the amount of movement of the magnetic head hardly changes, there is a drawback that the static position of the magnetic head deviates from the static target position, that is, on a predetermined track. It has already been proposed to correct the lead screw by selecting a material with the same coefficient of thermal expansion as the magnetic medium, but this poses problems in setting the reference point, etc., and complicates the configuration. This invention was made to solve the above-mentioned problems, and detects the ambient temperature of a magnetic medium, and depending on the detected value, changes the number of drive steps per track of the pulse motor to the drive steps at a reference temperature. The present invention provides a magnetic head feeding device using a pulse motor that can correctly position the magnetic head at a target position by increasing or decreasing the number of magnetic media in accordance with the expansion and contraction of the magnetic medium due to changes in ambient temperature.

Hereinafter, an embodiment in which the present invention is applied to a magnetic head feeding device for a floppy disk will be described with reference to the accompanying drawings. FIG. and drive the pulse motor in n steps at a certain temperature to drive the magnetic head 3 to 1.
Assume that when the data is moved by a track, the amount of movement is D, and data is written at the position of point B.

Next, when the temperature increases, the floppy disk 1 expands and moves from point B to a distance D2 from point A, but the amount of movement of the magnetic head 3 is still D, so it is one track. A deviation of D2-D occurs, and a deviation of m(D2-D,) occurs between m tracks (m is a positive integer).

The track pitch of a typical floppy disk is approximately 50.
At 0rm, there is a maximum track deviation of about 80 ym due to various factors, and the largest factor of this deviation is f. Approximately 50 m due to the expansion and contraction of the disc.
It is. FIG. 4 is a top view of the floppy disk 1, in which tracks 10 are arranged concentrically at equal pitches,
A typical floppy disk has 77 tracks.
As the track number N, the outermost track is named 0, and the innermost track is named 76. The floppy disk 1 expands and contracts in the radial direction depending on the temperature as shown by arrow R.
Each track shifts in radial direction in proportion to its distance from center C, but the position of center C does not change. Therefore, if the number of tracks distance from the center C is indicated as the track position M, track positioning based on temperature becomes easier. Now, if the distance k from the center C to the innermost track is an integer converted using the track pitch as a unit, then the track position M for the track number N is M=k+76-N
Also, if the number of driving steps D of the pulse motor 7 for one track is changed according to the temperature, if the pulse motor 7 is driven by the number of steps DM and the magnetic head 3 is moved from the center C position, , will be positioned exactly on the track position M. Table 1 shows the relationship between the number of drive steps M×D of the pulse motor 7 when the magnetic head 3 is moved from the center C to the track position M according to the track number N, the track position M, and the temperature.
Table 1 FIG. 5 is a block diagram showing an embodiment of the present invention, and the same parts as in FIG. 1 are given the same reference numerals.

Reference numeral 11 in FIG. 5 is a temperature sensor that detects the ambient temperature of the floppy disk. The number of drive steps is converted from the number of drive steps Do per track in the reference warm room o to a value D that includes a non-integer that is increased or decreased in response to expansion and contraction due to changes in the ambient temperature of the floppy disk 1, and is output. That is, when the temperature rises, the floppy disk 1 expands and stretches, so the number of drive steps D is increased, and when the temperature falls, the floppy disk 1 contracts, so the number of drive steps D is decreased. Reference numeral 13 denotes a track position memory which converts input of a track number N to which a magnetic head should be positioned for writing or reading, converts it to a track position M and outputs it, and is used for calculating P-ROM or k+76-N. It consists of arithmetic units, etc. that perform

14 is 1 of the floppy disk 1 at the reference temperature to
Non-volatile reference step memory for setting and storing the number of driving steps Do of the pulse motor 7 per track; 15;
is the output M of the track position memory 13, and the AD converter 12
This is a multiplier that multiplies the output D of the reference drive step memory 14 or the stored value Do of the reference drive step memory 14 and outputs the result. 12
The outputs of are applied to multipliers 15 via AND gates 17 in response to start signals ST of head positioning commands, that is, seek commands.

Reference numeral 18 indicates a track position register in which the output of the multiplier 15 is set by the initialization signal 1 or seek start signal ST input via the OR gate 19; and 20, the contents of the track position register 8 are set by the initialization signal 1 via the AND gate 21. This head position counter is equipped with an up/down counting function, and is inputted via an AND gate 22 gated by a seek signal SS.

The signal generated from the lock generation circuit 8 ◇・,gu・,◇2,
◇2, for example, every pulse of signal ◇, signal b'
The value is increased or decreased according to the polarity of the value. 23 indicates that the value of the track position register 18 is the head position counter 2.
The comparator outputs "11" when it is larger than the value of 0, "11" when it is smaller, and "0" when it matches, as a signal b', and the signal b' is sent to the head position counter 20.
is supplied to the clock generation circuit 8 via the OR gate 24,
The head position counter 20 performs an up-count operation when the signal injury is "11", and a down-count operation when the signal injury is "11", and the clock generation circuit 8 operates based on the signals. ，? 2
, and 2 are the generation order in which the magnetic head 3 is excited in the direction toward the inner circumference of the floppy disk 1 when the signal is "11", and the pulse motor 7 is excited in the direction toward the outer circumference when the signal is "11".

Further, the signal b' is applied directly to the AND gates 25 and 26 gated by the seek signal SS and to the AND gate 2 gated by the seek signal SS.
7, and when the signal b' is "11" or "11" during the presence of the seek signal SS, the gate of the clock generating circuit 8 is opened by the output thereof, and the signals ◇,, ◇, .
J2, J2 is generated, and when the signal is "0" or when there is no seek signal SS, the gate of the clock generation circuit 8 is closed, and the signal G...? ,,G2, stops the generation of J2. These track position memory 3, reference drive step memory 14, multiplier 15, track position register 1
8, head position counter 20, comparator 23, and various gates constitute drive step number determining means.

A specific example of the operation of this drive step number determining means will be described later, but in this regard, the output D of the AD converter 12 is connected to the non-extensible reference point (fourth point) of the floppy disk at the track position where the magnetic head is to be positioned. The number of driving steps of the pulse motor 7 at the time of positioning the magnetic head (at the time of seeking) is determined by the value obtained by converting the distance from the center C) of the figure into the number of tracks M, and converting the result MXD into an integer.

First, initialize the magnetic head 3 when the power is turned on.
is positioned as a reference point.

It is only necessary to set the center C of the floppy disk 1 as a reference point, which is not affected by the temperature, and move the magnetic head 3 from there on a predetermined track according to Table 1, but in reality, the upward drive screw 5 moves almost on the track 10. Since the range is limited, the magnetic head 3 is moved and positioned at a constant distance from the center C to serve as the second reference point, regardless of the expansion and contraction of the floppy disk due to temperature, by the principle of parallel movement due to so-called coordinate transformation. , by providing a stopper on the lead screw 5, the magnetic head 3 is moved in one direction no matter where it is on the track 10, is stopped near the outermost circumference or the innermost circumference of the track 10, and the distance at that time is calculated. It may be converted into the number of drive steps of the pulse motor 7.

In this case, the expansion and contraction due to the temperature of the lead screw 5 is ignored and the reference temperature is set. The number of drive steps Do per track on the floppy disk is selected to be an integer. The resting position of the magnetic head 3 at this time does not necessarily match the predetermined track position because the floppy disk 1 expands and contracts when the temperature changes, but for convenience of explanation, it is assumed to be a reference temperature reading position here. It is assumed that a stopper is installed on the lead screw 5 so that the magnetic head 3 stops at the outermost track position, that is, the position of track number 0. When the power is turned on, N=0 is input to the track position memory 13, Mo=k+76 - N=k+76 is outputted and becomes one input of the multiplier 15, and the reference is supplied via the AND gate 16 by the initialization signal 1. The multiplication result Mo×Do with the memory value Do of the drive step memory 14 is set by the initialization signal 1 supplied to the track position register 8 via the OR gate 19, and this value is also set by the head position counter 201 via the AND gate 21. Set by initialize signal 1.

Therefore, the output signal b' of the comparator 23 becomes "0" and the clock generation circuit 8 does not generate any signal.
The clock generation circuit 8 is separately supplied with an initialization signal 1 and a signal b (“11” in this case) that is preset depending on whether the initialization position of the magnetic head 3 is on the outer or inner circumference, and the magnetic head 3 is set at the outermost circumference position. Signal until it reaches the stopper of the lead screw 5 nearby, ◇, ◇2,
2 continues to occur. However, during this time, the signal ◇, is not supplied to the head position counter 20 because of the AND gate 22, and the head position counter 20 remains set to Do×Mo. For example, if k is 20 and Do is set to 20 at standard temperature, then pigeon x Do = (20 + 7
6) x20=1920. Next, for example, if a seek command to track number 75 is received, the seek track number N = 75, which is transferred at the same time as the seek command, is converted to M = k x 21 by the track position memory 13, and the temperature at that time is The difference is detected by the temperature sensor 1, and based on the detected amount, the AD converter 12 determines the number of drive steps per track at that temperature, for example,
D=20.1 and supplied to the multiplier 15 via the AND gate 17 in response to the seek start signal ST, so the multiplication result M×D=20.1×21=422.1
Then, the integer value 422 after truncating the decimal point is set in the track position register 18 by the seek 0 start signal ST' supplied via the OR gate 19. Since the head position counter 20 has already been set to a value indicating the current position of the magnetic head 3, that is, 1920,
The output b' of the comparator 23 becomes "-1", and the seek signal S
The AND gate 26 is opened at S, and the clock generation circuit 8
Signal from? ,,gu,,Ma 2, Minor 2 occur. The order of generation is determined by the signal b'=“-1”, and the magnetic head 3 moves toward the inner circumference of the floppy disk 1. The seek signal SS is also supplied to the AND gate 22 and is added to the head position counter 20, and since the signal injury is "-1", each pulse, in other words, each time the pulse motor 7 is driven one step. is counted down to
Eventually, when the value matches the numerical value 422 of the track position register 18, the output of the shark device 23 becomes "0", the gate of the clock generation circuit 8 is closed, and the magnetic head 3 is stopped.
The position corresponds to the position of track number 75 at the temperature t of the floppy disk. 0 When the power is turned off, the values in the track position register 18 and the head position counter 20 will disappear, and the position of the magnetic head 3 may also change, so it is necessary to initialize when the power is turned on again. For example, since the stop position of the magnetic head 3 is determined by the value of the head position counter 20, this position can be used as the next reference point.

Therefore, when a new seek command comes next, the track number N and the temperature t2 at that time are detected, and the value of the track position register 8 is updated and set by multiplying the detected amount by the step number D. The rest operates in the same manner as described above, and the magnetic head 3 is moved in either direction depending on the suitability of the output signal b of the comparator 23, and at the same time, the value of the head position counter 20 is increased or decreased to track the track. When the value becomes equal to the updated value of the position register 18, the operation is stopped. Of course, at this time, the magnetic head 3 is located at the temperature of the newly specified track number, and at the same time, this position also becomes the next reference point after coordinate transformation of the center C.
Similarly, the pulse motor 7 is
The number of driving steps D per track is changed, and the magnetic head 3 is moved to the designated track number position. In addition,
The embodiment shown in FIG. 5 is an example of a circuit in which a temperature sensor 11 is provided so that the number of drive steps per track of the pulse motor 7 can be changed depending on the ambient temperature.
It is not particularly limited to this circuit. For example, the number of reference steps Do per track is stored in the reference drive step memory 14.
Instead of setting the number of drive steps xD from the center C, which corresponds to the stop position of the magnetic head 3 during initialization,
o may be set and directly set in the track position register 18 or head position counter 20 at the time of initialization without passing through the multiplier 15. In addition, in place of the comparator 23, a subtracter is provided to obtain (Do x pigeon) - (MXD), and the pulse motor 7 is driven by the number of steps of the value of this result. It is something that can be implemented. Furthermore, although the case of a floppy disk as a magnetic medium has been described, the present invention can also be applied to a writing/initiating device using magnetic media of other shapes, such as a magnetic drum, magnetic tape, magnetic belt, etc., or a device that performs only one of them. can be applied.

As described above, the magnetic head feeding device according to the present invention detects the ambient temperature of the magnetic medium and controls the pulse mode.
The number of drive steps per track is increased or decreased from the number of drive steps (an integer) at a reference temperature according to the slight expansion and contraction amount due to changes in the ambient temperature of the magnetic medium, and converted to a value including non-integers, and the expansion and contraction of the magnetic medium is Since the number of drive steps of the pulse motor when positioning the magnetic head is determined by the integer value obtained by calculating the number of tracks from the non-shrinking reference point to the track position where the magnetic head should be positioned, the magnetic medium The amount of track position deviation of the magnetic head due to the expansion and contraction of the magnetic head is approximately 1/lower than that of the conventional magnetic head, even considering errors such as expansion and contraction of the lead screw, deviation of the center position of the magnetic disk, etc., and rounding down to the decimal point after multiplication. , not only the positioning accuracy is greatly improved, but also the track density can be approximately doubled, which is a great effect.

[Brief explanation of drawings]

Fig. 1 is a block configuration diagram showing an example of a conventional pulse motor external magnetic head feeding device, Fig. 2 is a two-phase clock signal waveform diagram generated to step drive the pulse motor, and Fig. 3 is a block diagram showing an example of a magnetic head feeding device using a conventional pulse motor. An explanatory diagram of the track deviation of
FIG. 4 is a top view of a floppy disk, and FIG. 5 is a block diagram showing an embodiment of the present invention. 0 1...Floppy disk, 3...Magnetic head, 5"" lead screw, 7.../Gurusu motor, 8...Clock generation circuit, 9...Drive circuit, 10...Track, 11...Temperature sensor, 12...AD converter, 1 3...Track position memory, 14...Reference drive step memory, 15... ... Multiplier, 18 ... Track position register, 20 ... Head position counter, 23 ... Comparator. Fig. 1 Fig. 2 Fig. 3 Fig. 4 Figure 5

Claims (1)

[Claims] 1. In a magnetic head feeding device in which a magnetic head is fed by driving a pulse motor in multiple steps per track, and the magnetic head is moved over a magnetic medium and positioned at a predetermined track position, the ambient temperature of the magnetic medium is detected. A temperature sensor, and the number of driving steps per track of the pulse motor is changed from the number of driving steps (D_0) at the reference temperature to the expansion and contraction of the magnetic medium due to changes in the ambient temperature according to the detected value of the temperature sensor. a converting means for converting the value (D) into a value (D) including non-integers increased or decreased; The result of multiplying the converted value (M) by the number (
1. A magnetic head feeding device using a pulse motor, comprising drive step number determining means for determining the number of drive steps of the pulse motor when positioning the magnetic head based on a value obtained by converting MxD) into an integer.