JPH073814Y2 - Stepping motor for floppy disk drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a structure of a stepping motor mounted on a carriage of a floppy disk device for moving a magnetic head for writing and reading information.

[Prior Art] A floppy disk device writes and reads information to and from a floppy disk by a magnetic head mounted on a carriage. At this time, the floppy disk is rotated and the magnetic head is linearly moved to write and read predetermined information. In order to linearly move the magnetic head, a rotary motion of a stepping motor that rotates at a predetermined step angle is used.

The mechanism for converting the rotary motion of the rotary shaft of the stepping motor into the linear motion of the magnetic head is described below. That is, a spiral groove is provided in the lead screw that is the rotation shaft of the stepping motor, and an engaging element that engages with the spiral groove is provided in the carriage. Then, the number of pulses corresponding to a predetermined movement amount is input to the stepping motor, the lead screw is rotated at a predetermined step angle, the carriage engaging with the spiral groove is linearly moved, and the magnetic head is moved by a predetermined amount. ing.

Recently, a floppy disk device which can be driven by a battery with a single voltage of 5V has been incorporated into a portable information device and has been commercialized. In such a portable information device, it is indispensable to reduce the power consumption of the floppy disk device because it is driven by a battery.

During the standby time when the magnetic head is not reading or writing information, the power is turned off with the minimum necessary control system left, and the standby time for reading and writing that occupies most of the operating time of the floppy disk device. It has been proposed to reduce power consumption.

[Problems to be solved by the invention] However, when the power of the stepping motor is turned off, the position of the magnetic head with respect to the floppy disk becomes uncertain, and when the power is next turned on to drive the stepping motor,
There is a problem that the position of the magnetic head is displaced with respect to the floppy disk by at least a dimension corresponding to one step angle. This is because in order to reduce the power consumption of the floppy disk drive, it is necessary to reduce the index torque of the stepping motor, and the spiral groove of the lead screw and the engaging element are in mechanical contact with each other, so that the load is large. Become. Therefore, when the power of the stepping motor is turned off, the stationary position of the lead screw, which is the rotating shaft, is not stable, and the magnetic head position varies.

Therefore, there is a floppy disk device having a structure in which the power of the stepping motor is turned off during standby between reading and writing and the rotating shaft is held by an external friction member such as a leaf spring in the radial direction or the thrust direction of the rotating shaft of the stepping motor. However, there arises a problem that hysteresis is caused due to the difference in the rotation direction of the stepping motor and the positioning accuracy of the magnetic head is deteriorated.

Therefore, conventionally, there is a problem that the power supply of the stepping motor cannot be cut off and the current consumption cannot be reduced.

[Object of the Invention] Therefore, an object of the present invention is to provide a stepping motor of a floppy disk device having a structure in which the position of the magnetic head is not indefinite even when the power of the stepping motor is turned off.

[Means for Solving the Problems] In order to achieve the above object, the stepping motor of the floppy disk device of the present invention adopts the following means.

A stepping motor of a floppy disk device according to the present invention comprises a stepping motor and a carriage. The stepping motor has a lead screw having a spiral groove provided on a rotating shaft for moving the carriage and a bush provided on an outer peripheral portion of the lead screw. And a yoke provided on the outer peripheral portion of the bush and made of a magnetic material, a magnet provided on the outer peripheral portion of the yoke, and a stator having a coil arranged on the outer peripheral portion of the magnet.The stepping motor is fixed to the housing, and the carriage is The read screw is equipped with a magnetic head for writing and reading information to and from the floppy disk, and an engagement element that engages with the spiral groove of the lead screw and converts the rotational movement of the rotating shaft into the linear movement of the magnetic head. Stepping between the groove forming area and the housing An index wheel having a number of index grooves obtained by dividing 360 degrees by one step angle of the rotor is provided, an engaging member that engages with the index groove of the index wheel is provided at the housing, and when the power of the stepping motor is cut off, The index groove of the index wheel is engaged with the engaging member to stop the magnetic head mounted on the carriage at a predetermined position.

[Operation] In the present invention, the lead screw is provided with an index wheel that forms an index groove, and an engaging member that engages with the index groove is provided in the housing to mechanically control the rest position of the lead screw. The structure is adopted.

Therefore, it is possible to suppress the phenomenon that the magnetic head position varies due to a small index torque and a large load, which occurs when the power of the stepping motor is turned off.

As a result, when waiting for information reading and writing,
It is possible to turn off the power of the stepping motor, and it is possible to reduce the power consumption of the floppy disk device.

[Embodiment] The structure of a stepping motor of a floppy disk device according to an embodiment of the present invention will be described below with reference to the drawings.

1 and 2 show a stepping motor of a floppy disk device according to a first embodiment of the present invention.
The drawing is a sectional view, and FIG. 2 is a side view. Below, the first
The description will be made by alternately referring to FIG. 2 and FIG.

Lead screw that is the rotating shaft of the stepping motor 10
28 is provided with a spiral groove. The spiral groove engages with an engaging element provided on a carriage (not shown), and has a role of linearly moving the magnetic head mounted on the carriage by the action of the rotating element of the lead screw 28.
Further, the bush 20 is press-fitted into the end region of the lead screw 28 where the spiral groove is not formed, and the yoke 12 made of a magnetic material and the magnet 14 are fixed to the outer peripheral portion of the bush 20. Further, the stator 18 having the coil 16 formed thereon is connected to the magnet 14
It is placed on the outer periphery of.

By doing so, the lead screw 28 for fixing the magnet 14 is rotated by a step angle proportional to the number of pulses input from the outside, and the magnetic head engaging with the spiral groove is linearly moved by a predetermined amount. Can be written and read.

The stepping motor 10 is fixed to the housing 24, and the lead screw 28 is rotatably supported by bearings 30 provided at both ends thereof.

The lead screw 28 is formed in the spiral groove forming area and the housing.
Index groove 32 having a number obtained by dividing 360 degrees by one step angle of the stepping motor 10 between 24 and 24.
The index wheel 30 forming the is fixed. That is, one step angle of the stepping motor 10 is, for example,
If it is 20 degrees, 360 degrees ÷ 20 degrees = 18, and 18 index grooves 32 are provided on the outer periphery of the index wheel 30 at equal intervals. The index groove 32 is a circular arc groove.

Further, the housing 24 is provided with an engaging member 34 that is elastically engaged with the index groove 32 by the elastic member 22. The elastic member 22 is composed of a coil spring.

When the stepping motor 10 is rotated, the engaging member 34 having a spherical tip end slides smoothly on the outer peripheral portion of the index wheel 30.

When waiting for reading and writing of information, that is, when the power of the stepping motor 10 is turned off, the index groove 32
The tip of the engaging member 34 is engaged in the
28 is stopped at a predetermined position, and the magnetic head can be positioned by the mechanical engagement between the index groove 32 and the engaging member 34.

Therefore, the phenomenon that the position of the magnetic head becomes uncertain due to the small index torque and the large load, which occurs when the power of the stepping motor 10 is turned off, does not occur. That is, when the power is turned on and the stepping motor 10 is driven after the power is turned off, the position of the magnetic head does not shift relative to the floppy disk by a dimension corresponding to at least one step angle. Does not cause hysteresis.

As a result, even if the power of the stepping motor 10 is turned off, the magnetic head is stopped at the predetermined position, and the power of the stepping motor 10 can be turned off during the standby for writing and reading of information. Therefore, low power consumption of the floppy disk device can be achieved.

FIG. 3 is a sectional view showing a stepping motor according to a second embodiment of the present invention. In the embodiment shown in FIG. 3, when the magnetic head writes and reads information,
That is, the structure in which the engagement between the index groove and the joining member is released when the lead screw is rotated is adopted.

As shown in FIG. 3, a solenoid 36 having a power source that interlocks with the power source of the stepping motor 10 is provided on the engaging member 34 on the end surface opposite to the engaging portion between the index groove 32 and the engaging member 34. Since the configuration other than the provision of the solenoid 36 is the same as that of the first embodiment described with reference to FIGS. 1 and 2, detailed description thereof will be omitted.

When the magnetic head performs writing / reading operation, that is, when the stepping motor 10 rotates, the solenoid 36
The magnetic attraction to the engaging member 34 and the index groove 32
Disengage from.

On the contrary, when the magnetic head is in the standby state where writing and reading are not performed, that is, when the stepping motor 10 is stopped, the engaging member 34 is mechanically engaged with the index groove 32 of the index wheel 30 by the action of the elastic member 22. Therefore, the lead screw 28 can be reliably stopped. Therefore, the phenomenon that the magnetic head position varies does not occur.

The embodiment described with reference to FIG. 3 has the same effect as that of the first embodiment, and further has the effect that the load during rotation of the lead screw 28 can be reduced.

Although the lead screw type has been described above, the configuration of the present invention can also be applied to a steel belt type stepping motor.

[Effects of the Invention] As is clear from the above description, the index wheel that forms the index groove is fixed to the lead screw, and the housing is provided with the engaging member that engages with the index groove. The structure is such that it is mechanically controlled. Therefore, the phenomenon that the position of the magnetic head is displaced when the power of the stepping motor is turned off does not occur.

As a result, when waiting for information reading and writing,
It is possible to turn off the power of the stepping motor, and it is possible to reduce the current consumption of the floppy disk device. Therefore, it becomes possible to incorporate a high-performance floppy disk device into a small portable information device.

[Brief description of drawings]

1 and 2 show a stepping motor of a floppy disk device according to a first embodiment of the present invention, FIG. 1 is a sectional view, FIG. 2 is a side view, and FIG. 3 is the present invention. FIG. 6 is a cross-sectional view showing a stepping motor of a floppy disk device in the second example of FIG. 30 …… Index wheel, 32 …… Index groove, 34 ……
Engagement member.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-57-36452 (JP, A) JP-A-59-2509 (JP, A) JP-A-59-172947 (JP, A) JP-B-45- 22771 (JP, B1)

Claims (2)

[Scope of utility model registration request] 1. A stepping motor for a floppy disk device having a lead screw (28), an index wheel (30) and an engaging member (34), the lead screw (28) moving a carriage. It is a spiral groove provided on the rotary shaft for the purpose of engaging the engaging element and converting the rotary motion of the rotary shaft into the linear motion of the magnetic head mounted on the carriage. The index wheel (30) is the lead screw of the rotary shaft. (28) Fixed to the vicinity of the stepping motor (10) 1
It has index grooves (32) divided by 360 degrees by one step angle, and when the power of the stepping motor (10) is cut off, the index grooves (32) of the index wheel (30)
A stepping motor for a floppy disk device, which elastically engages with the engaging member (34) to stop the magnetic head at a predetermined position. 2. The engaging member (34) has an index groove (32).
And the engaging member (34), the solenoid (3
The stepping motor for a floppy disk device according to claim 1, which is disengaged from the index groove (32) according to 6).