JPS61267974A - Carriage driving device - Google Patents

Abstract

PURPOSE:To eliminate the error of read and the write of a magnetic head which is caused by an external vibration, etc., by detecting the spiral groove of a driving shaft for making a carriage execute a reciprocating motion by a sensor, using its output as a feedback signal and correcting the stop position of a pulse motor. CONSTITUTION:A carriage 5 is brought to the reciprocating motion by driving a driving shaft 2 having a spiral groove 3 by a pulse motor 1 and using a guide shaft 4 as a guide. In a sensor 6, the slit 7 of a narrow width is provided on the lower side of the shaft 2 and the emitted light of a light emitting element provided on the upper part of the shaft is received by a photodetecting element provided on the lower side of the slit 7, but the groove 3 moves so as to cross the slit by the rotation of the shaft 2, therefore, the light-receiving quantity is varied. Accordingly, the stop position of the motor 1 is corrected by using the output voltage of a terminal 8 as a feedback signal, a magnetic head which is loaded on the carriage 5 is positioned exactly, and the error of read and write of a head can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a carriage drive device for reciprocating a carriage by rotating a drive shaft having a spiral groove on its outer peripheral surface using a pulse motor.

[Conventional technology]

Recent word processors, personal computers, etc. are increasingly using floppy disks and read disks as external storage devices. A carriage drive device is provided.

Various types of conventional carriage drive devices have been proposed, but most of them use pulse motors in order to reduce costs and satisfy the 95 conditions.

[Problem that the invention seeks to solve]

However, the stopping position of this pulse motor changes due to friction and external vibrations, so conventional carriage drive devices that use such pulse motors to move a carriage carrying a magnetic head tend to be used inadvertently at an angle. In some cases, changes in the stop position of the pulse motor may affect the position of the magnetic head, resulting in problems such as erroneous writing and reading errors.

Furthermore, a similar situation may occur if a shock or the like is accidentally applied while the device is in use, making it practically difficult to apply it to a portable external storage device in particular.

The present invention has been made in order to solve such problems, and provides a carriage drive that can prevent the occurrence of erroneous writing and erroneous reading of magnetic heads caused by tilting of the device, external impact, etc. The purpose is to realize a device.

[Means for solving problems]

In order to achieve the above-mentioned object, the present invention provides a carriage that linearly reciprocates a carriage threadedly engaged with the drive shaft by rotating the drive shaft with a spiral groove on the outer peripheral surface using a pulse motor. In the drive device, a sensor for detecting the groove and a correction means for correcting the stop position of the pulse motor are provided. [Function] According to the above-mentioned means, the stop position of the pulse motor is not subject to external force, etc. , the pulse motor can be returned to its original stop position by the correction means using the output of the sensor as a feedback signal.

Therefore, even if the device is tilted or subjected to external impact, the pulse motor can always be stopped at the original stop position, thereby preventing erroneous writing or erroneous reading of the magnetic head mounted on the carriage. It can be prevented.

〔Example〕

Examples will be described below with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of a carriage driving device according to the present invention, and FIG. 2 is a plan view of the main part of FIG.

First, the first factor is a pulse motor 1, a drive shaft 2 which is rotationally driven by the pulse motor 1, and a spiral groove 3 is provided on the outer peripheral surface of the drive shaft 2. There is.

4 is a guide shaft arranged parallel to the drive shaft 2; 5 is a carriage on which a magnetic head (not shown) is mounted; one end of the carriage 5 is threadedly engaged with the drive shaft 2; The guide shafts 2 and 4 are engaged with each other, and are reciprocated on the drive shaft 2 and the guide shaft 4 by 20 rotations of the drive shaft.

A sensor 6 detects the groove 3 of the drive shaft 2, and a side light is disposed near the pulse motor 1. As shown in FIG. 2, this sensor 6 includes a narrow slit 7 located below (or above) the groove 3, a light emitting element (not shown) located above the groove 3, and a slit 7 located above the groove 3. It is equipped with a light-receiving element (also not shown) located at the bottom.
When light from the light emitting element is received by the light receiving element through the slit 7, its output appears at the output terminal 8.

FIG. 3 is a circuit diagram of a correction means for correcting the stop position of the pulse motor 1 using the output of the output terminal 8 as a feedback signal. In the figure, 9 is a transistor connected to the pulse motor 1, and 10 is a transistor connected to the sensor 6. In the voltage conversion circuit, v and v2 are voltage sources.

Note that the voltage conversion circuit 10 is a known one.

Next, the effect will be explained.

First, when the pulse motor 1 is driven, the drive shaft 2 rotates in response to the rotation and stop of the pulse motor 1.

At this time, the light output from the light emitting element passes through the slit 71c.
However, as is clear from FIG. 2, the rotation of the drive shaft 2 causes the groove 3 provided on the outer peripheral surface of the drive shaft 2 to move across the slit 7, so that the slit Tf :The amount of light that passes through changes and the amount of light that is blocked between the slit grooves 3 changes, so the amount of light that passes through the slit T also changes accordingly. As a result, the output voltage of the sensor 6 changes.

The output waveform of the sensor 6 at this time is shown in FIG.

On the other hand, when the drive shaft 2 rotates as described above, the carriage 5 linearly moves to the right or left in FIG. 1 in response to this rotation.

Therefore, an output voltage corresponding to the position of the carriage 5 is obtained from the output terminal 8 of the sensor 6.

In this embodiment, the stop position of the repulse motor 1 is corrected by the correction means shown in FIG. 3 using the output voltage of the output terminal 8 as a feedback signal.

In FIG. 3, while the pulse motor 1 is rotating, the transistor 9 is turned on, and a current less than the voltage source v1 is supplied to the pulse motor 1. Further, the voltage generated at the output terminal 8 of the sensor 6 is positively converted by a known voltage conversion circuit 10 n5.
It becomes a voltage source v2 that supplies current while the pulse motor 1 is stopped. FIG. 5 schematically shows the waveform of this voltage source v2.

Therefore, when the stop position of the pulse motor 1 changes due to an external impact applied to the drive device of this embodiment, the position of the groove 3 of the drive shaft 2 with respect to the slit 7 of the sensor 6 changes accordingly. Therefore, the output voltage appearing at the output terminal 8 changes. In response to this changed output voltage, the voltage of the voltage source v2 increases, the torque generated in the pulse motor 1 increases, and the pulse motor 1 rotates toward its original stop position to perform position correction. With this position correction operation, the output voltage of the sensor 6 also changes and the voltage source v2 decreases, and when the position correction is completed, the current flowing through the pulse motor 1 is kept at a minimum.

Incidentally, Vmin and vmax shown in FIG. 5 can be arbitrarily determined depending on the size of the load system and the characteristics of the pulse motor 1.

〔Effect of the invention〕

As explained above, the present invention provides a sensor that detects the groove of a drive shaft rotated by a pulse motor, and a correction means that corrects the stop position of the pulse motor, so that the device is tilted when subjected to an external force. When the stop position of the pulse motor changes due to use in the motor, the output of the sensor is used as a feedback signal to use the correction means to return the stop position of the pulse motor to the original stop position.
The effect of eliminating the influence on the carriage moving by the drive shaft and preventing erroneous reading and writing of the magnetic head mounted on the carriage is achieved.
This also allows application to a portable external storage device.

In addition, the present invention has the effect that it can be realized at low cost without using special sensors, etc. Furthermore, it can be applied not only to a drive device for a carriage on which a magnetic head is mounted, but also for a drive device for a carriage on which a print head of a printer is mounted, etc. , it can be used in any device that uses a drive shaft with a spiral groove, and similar effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a carriage drive device according to the present invention, FIG. 2 is a plan view of the main parts thereof, FIG. 3 is a circuit diagram showing correcting means for the stop position of the pulse motor, and FIG. 1
FIG. 5 is a diagram showing the output waveform of the sensor in FIG. 3, and FIG. 5 is a diagram showing the waveform of the voltage source in FIG. 1: Pulse motor 2: Drive shaft 3: Groove 4: Guide shaft 5: Carriage 6: Sensor 1 slit
8: Output terminal 9: Transistor 10: Voltage conversion circuit Patent applicant: Oki Electric Industry Co., Ltd. Agent Patent attorney: Takashi Kanakura 2. Perspective view showing an embodiment of the present invention - 1 [m Plan view of the main part of Fig. 1 @ 2 Circle Diagram showing the correcting means for the stop position of the pulse motor 31 Diagram showing the output waveform of the position sensor Diagram showing the waveform of the stop position voltage source v2 5 l

Claims (1)

[Scope of Claims] 1. A pulse motor, a drive shaft having a spiral groove on its outer peripheral surface and rotationally driven by the pulse motor, and a drive shaft that is screwed onto the drive shaft and is driven by the rotation of the drive shaft. A carriage drive device equipped with a carriage that reciprocates linearly, comprising: a sensor for detecting a groove on a drive shaft; and means for correcting the stop position of the pulse motor using the output of the sensor as a feedback signal. Carriage drive device.