JP2576877B2 - Step motor driving device and head moving device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a step motor driving device and a head moving device. More specifically, the present invention relates to a step motor driving device and a head moving device that perform a settling operation by slightly vibrating a step motor.

[Conventional technology]

In general, a stepping motor is often used in a head moving device of a magnetic recording device. Particularly, in a recording device having a small track density such as a floppy disk, almost only a stepping motor may be used. However, there is a position error with hysteresis in the step motor, and a track position error occurs at the time of stop due to a slight difference in load, a difference in forward / reverse movement direction and a difference in movement speed until the stop, and reliability is reduced. Let me do it. In order to reduce the hysteresis, it is possible to use a method of reducing the value by a special control mode when the stepping motor is stopped, instead of using an expensive stepping motor or excessively supplying a large driving current. As an example, in the conventional example of Japanese Utility Model Application Laid-Open No. 60-160096, a mode in which vibration is performed to the front and rear phases at the time of stoppage has been proposed.

[Problems to be solved by the invention]

However, the method of vibrating the excitation phase of the step motor back and forth at the time of stoppage as in the conventional example described above is very critical, and the effect is required unless the type of step motor is selected and the vibration is performed at the most effective time interval. I can't get it. In addition, in the case of an inappropriate time pattern, there is a danger that the hysteresis is increased due to an adverse effect. Therefore, the above-mentioned problem makes it difficult to make the excitation phase switching means of the step motor into an IC when it is integrated. As another problem, it is necessary to prepare a vibration pattern at the time of stop for each final combination of stop phases, and the storage unit (RO
M) becomes complicated.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems and to provide a stepping motor drive device and a head moving device that perform a settling operation by a method other than a gripper.

[Means for solving the problem]

A first stepping motor driving device according to the present invention is a stepping motor driving device having two driving windings, wherein an excitation phase switching for switching an excitation phase of the stepping motor by switching control of an excitation current supplied to the driving windings. Means, and excitation currents provided corresponding to each of the drive windings and supplied to the drive windings are two of a strong excitation current and a weak excitation current.
And an exciting current switching means for instructing a switching to a step.
A state where a strong excitation current is supplied to the drive winding and a weak excitation current is supplied to the second drive winding, and a state where a weak excitation current is supplied to the first drive winding and the second A state in which the strong exciting current is supplied to the drive winding is alternately repeated.

A second stepping motor drive device according to the present invention is a stepping motor drive device having two drive windings, wherein an excitation current to be supplied to the drive windings is controlled to switch the excitation phase of the stepper motor. Means, and excitation currents provided corresponding to each of the drive windings and supplied to the drive windings are two of a strong excitation current and a weak excitation current.
Excitation current switching means for instructing switching to a step, wherein when the excitation phase is fixed, a weak excitation current is supplied to the drive winding, and after the excitation phase is switched by the excitation phase switching means, A state in which a strong excitation current is supplied to one of the drive windings and a weak excitation current is supplied to the second drive winding; and a state in which the weak excitation current is supplied to the first drive winding and the second A state in which a strong excitation current is supplied to the drive windings is alternately repeated, and finally, a strong excitation current and then a weak excitation current are supplied to both the drive windings.

According to a first head moving device of the present invention, in a head moving device provided with a step motor having two drive windings, an excitation phase for switching an excitation phase of the step motor by switching and controlling an excitation current supplied to the drive winding. Switching means, and excitation current switching means provided corresponding to each of the drive windings and instructing the excitation current to be supplied to the drive windings to be switched into two stages, a strong excitation current and a weak excitation current. After the excitation phase has been switched by the excitation phase switching means, a strong excitation current is supplied to the first drive winding and a weak excitation current is supplied to the second drive winding; The state in which the weak excitation current is supplied to the drive winding and the strong excitation current is supplied to the second drive winding is alternately repeated.

According to a second head moving device of the present invention, in a head moving device provided with a step motor having two drive windings, an excitation phase for switching an excitation phase of the step motor by switching and controlling an excitation current supplied to the drive winding. Switching means, and excitation current switching means provided corresponding to each of the drive windings and instructing the excitation current to be supplied to the drive windings to be switched into two stages, a strong excitation current and a weak excitation current. When the excitation phase is fixed, a weak excitation current is supplied to the drive winding. After the excitation phase is switched by the excitation phase switching means, a strong excitation current is supplied to the first drive winding. And a state in which a weak excitation current is supplied to the second drive winding, and a state in which a weak excitation current is supplied to the first drive winding and a strong excitation current is supplied to the second drive winding And alternately Is, finally, strong exciting current to both of the drive winding and then a weak excitation current, characterized in that it is supplied.

[Action]

In the configuration of the present invention described above, after the step motor sends the head to the target track, the balance of the exciting force of the two coils is changed from strong to weak while being fixed to the exciting phase that finally stops. be changed. As a result, the step motor reciprocates around the target stop position within a range not too large, and finally ends the settling operation by balancing the excitation of the two coils, and stops after removing the hysteresis.

〔Example〕

 Hereinafter, the present invention will be described in detail based on examples.

FIG. 1 is a circuit diagram of a head moving device according to an embodiment of the present invention. Reference numerals 1 and 2 denote two windings of the stepping motor, each having two phase coils, and an intermediate point serving as a power supply terminal. Reference numeral 3 denotes a movement command from the host device. This is an excitation control circuit that receives the STEP and the DIR as a movement direction command at that time, and generates an excitation phase signal of the step motor and a signal of the intensity of the excitation. 4 ~
Reference numeral 7 denotes a driver which receives the excitation phase signal outputs φ _{A to} φ _D of 3 and switches the phase of the step motor coil, and 8 and 9 receive the output signals P _A and P _B of 3 and output step motor drive transistors 10 and 11 respectively. This is a driver for driving. When the excitation is strong, the transistors 10 and 11 turn on, and when the excitation is weak, the limiting resistors 13 and 16
Excited through 1215 is a base resistor, and 14 and 17 are noise absorbing capacitors at the time of transistor switching.

When the signal DIR and STEP is input transistors 10 and 11 are both turned ON, the step motor phi _A to [phi] _D is changed sequentially switching is rotated. STEP signal is fixed to one of a total of two phases signals of either the phi _B and phi _D of it comes to phi _A and phi _C not input. Then, P _A and P _B are alternately switched, and the step motor coils 1 and 2 make small vibrations.
Both P _A and P _B are strongly excited and the settling is completed, after which P _A and P _B
Both are turned OFF, weakly excited, and enter the holding mode. As compared with the conventional general step motor driving means, the transistors 10 and 11 are provided in a separate system, and the step motor coils 1 and 2 are configured so that the excitation can be separately switched between strong and weak.

FIG. 2 is a phase switching illustration showing the made the switching of the step motor phase φ _A ~φ _D. Double circle indicates that is strongly excited by P _A or P _B, a single circle indicates a weak excitation. The movement of one track is performed by one step of the step motor, and the left side of the dotted line is the track from the track 00.
The movement to 01 and the right side show the movement from track 02 to track 01. T ₁ is a timing of the last movement, T ₂ through T ₆ represents the timing of each intensity switching of settling time. Second
After moving Figure At a to the track 01, phi repeated strong excitation of the two _C strong excitation → phi _B, At a T ₆ is phi _C and phi _B moves to both strong excitation has been then hold mode .

FIG. 3 is a rotation change diagram showing a state in which the rotation of the step motor is changed by the operation shown by the phase switching explanatory diagram of FIG. Eventually, no matter which of track 00 or track 02 is moved to track 01, it is settled accurately without hysteresis.

Also, if the configuration of FIG. 1 is used, the hysteresis of the step motor can be reduced with a relatively simple circuit configuration,
A head moving device with good position accuracy can be realized.

FIG. 4 is a circuit showing the excitation control circuit 3 of FIG. 1 in detail. D-type flip-flops (hereinafter referred to as FF) 21 and 22 and exclusive OR gates 23 and 24 are connected to the excitation phase signal φ _A
To form a ~φ _D. On the other hand, starting with the STEP signal,
Sequentially forming a timing T ₁ through T ₆ by the clock signal CK timer 20 and energized by the gate 25 to 35 intensity signals P _A and P _B
Is formed. There is no need to use a ROM, and it can be configured with only a few gates.

FIG. 5 is a timing chart showing the output T ₁ through T ₆ of timer 20 of FIG. 4. Timer 20 is T ₁ if STEP signal at regular intervals continuously input since it is initialized is retained every time the STEP signal is input, therefore it continues at even strong excitation P _A and P _B Become.

〔The invention's effect〕

As described above, in the first stepping motor drive device and the head moving device of the present invention, after the excitation phase is switched by the excitation phase switching means, the strong excitation current is supplied to the first drive winding and the second The state where the weak excitation current is supplied to the drive winding and the state where the weak excitation current is supplied to the first drive winding and the strong excitation current is supplied to the second drive winding are alternately repeated. Thus, the settling operation can be performed without being largely influenced by the characteristics of the step motor.

Further, in the second step motor driving device and the head moving device of the present invention, the weak excitation current is supplied to the drive winding when the excitation phase is fixed, and after the excitation phase is switched by the excitation phase switching means, A state in which a strong excitation current is supplied to the first drive winding and a weak excitation current is supplied to the second drive winding, and a state in which the weak excitation current is supplied to the first drive winding and the second drive winding The state in which the line is supplied with the strong excitation current is alternately repeated, and finally, both the drive windings are supplied with the strong excitation current and then the weak excitation current, so that the hysteresis can be more reliably eliminated. At the same time, when the excitation phase is fixed, the power of the step motor is also weakened, and the amplitude of the free vibration, which is a source of noise, is also reduced. Solution I can decide.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a head moving device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of phase switching for explaining the operation of FIG. FIG. 3 is a change diagram of the rotation of the step motor showing the effect of the present invention. FIG. 4 is a detailed circuit diagram of the excitation control circuit 3 of FIG.
The figure is a timing chart of the timer 20 in FIG. 1, 2, step motor coil, 4 to 9, driver 10, 11 ... excitation drive transistor

Claims (4)

(57) [Claims] 1. An apparatus for driving a step motor having two drive windings, comprising: an excitation phase switching means for switching an excitation current supplied to the drive winding to switch an excitation phase of the step motor; And exciting current switching means for instructing to switch the exciting current supplied to the drive winding into two stages of a strong exciting current and a weak exciting current. A state in which a strong excitation current is supplied to the first drive winding and a weak excitation current is supplied to the second drive winding after the phase is switched; and a weak excitation current is supplied to the first drive winding. And a state where a strong excitation current is supplied to the second drive winding is alternately repeated. 2. An apparatus for driving a step motor having two drive windings, comprising: an exciting phase switching means for switching and controlling an exciting current supplied to the drive winding to switch an exciting phase of the step motor; And excitation current switching means for instructing the excitation winding to be supplied to the drive winding to be switched into two stages, a strong excitation current and a weak excitation current, wherein the excitation winding is fixed when the excitation phase is fixed. A weak excitation current is supplied to the line, and after the excitation phase is switched by the excitation phase switching means,
A state in which a strong excitation current is supplied to the first drive winding and a weak excitation current is supplied to the second drive winding, and a state in which a weak excitation current is supplied to the first drive winding and the second A step in which a strong excitation current is supplied to the drive windings is alternately repeated, and finally, a strong excitation current and then a weak excitation current are supplied to both the drive windings. apparatus. 3. A head moving device provided with a step motor having two drive windings, wherein an exciting phase switching means for switching an exciting current of the step motor by switching and controlling an exciting current supplied to the drive winding; Exciting current switching means provided corresponding to each of the drive windings and instructing the excitation current to be supplied to the drive winding to be switched into two stages of a strong excitation current and a weak excitation current; After the excitation phase is switched by the means, a state in which a strong excitation current is supplied to the first drive winding and a weak excitation current is supplied to the second drive winding; And a state in which a weak exciting current is supplied and a strong exciting current is supplied to the second drive winding. 4. A head moving device provided with a step motor having two drive windings, wherein an exciting phase switching means for controlling an exciting current supplied to the drive winding to switch an exciting phase of the step motor, Exciting current switching means provided corresponding to each of the drive windings and instructing the excitation current to be supplied to the drive windings to be switched into two stages of a strong excitation current and a weak excitation current. A weak excitation current is supplied to the drive winding, and after the excitation phase is switched by the excitation phase switching means,
A state in which a strong excitation current is supplied to the first drive winding and a weak excitation current is supplied to the second drive winding, and a state in which a weak excitation current is supplied to the first drive winding and the second A state in which a strong excitation current is supplied to the drive windings is alternately repeated, and finally, a strong excitation current and then a weak excitation current are supplied to both the drive windings. .