JPH073815Y2 - Stepping motor for floppy disk device - 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, the 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 lead screw, which is a spiral groove, is provided on the rotating shaft of the stepping motor, and an engaging element that engages with the groove of the lead screw is provided on the carriage. Then, the number of pulses corresponding to a predetermined movement amount is input to the stepping motor, the rotating shaft is rotated at a predetermined step angle, the carriage engaging with the groove of the lead screw 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.

When the magnetic head is not reading or writing information during standby, turn off the power with the minimum required control system
It has been proposed to reduce the power consumption during the standby for reading and writing, which occupies most of the operating time of the floppy disk device.

[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,
Next, when the power is turned on and the stepping motor is driven, there arises a problem that the position of the magnetic head shifts with respect to the floppy disk by at least a dimension corresponding to one step angle. In order to reduce the power consumption of the floppy disk device, it is necessary to reduce the index torque of the stepping motor, and the load is increased because the groove of the lead screw and the engaging element are in mechanical contact with each other. Therefore, when the power of the stepping motor is turned off, the stationary position of the rotary shaft is not stable, and the magnetic head position varies.

Therefore, the power of the stepping motor is turned off during the waiting for reading and writing, and the external friction member in the radial direction or the thrust direction of the rotating shaft of the stepping motor,
For example, there is a floppy disk device having a structure in which a rotary shaft is held by a leaf spring. However, there is hysteresis caused by the difference in the direction of rotation of the stepping motor,
There is a problem that the positioning accuracy of the magnetic head deteriorates.

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.

The stepping motor of the floppy disk device of the present invention includes a stepping motor and a carriage. The stepping motor includes a rotating shaft forming a lead screw for moving the carriage, a bush provided on an outer peripheral portion of the rotating shaft, and a bush. It is provided with a yoke made of a magnetic material provided on the outer peripheral portion, 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, and the stepping motor is fixed to the housing, and the carriage is attached to the floppy disk. It has a magnetic head for writing and reading information, and an engaging element that engages with the lead screw and converts the rotational movement of the rotating shaft into the linear movement of the magnetic head, and the rotating shaft is between the lead screw forming region and the housing. And one step angle of the stepping motor A polygonal part having a number of angles less than 360 degrees is provided, the housing is provided with a spring member that engages with the polygonal part, and when the power of the stepping motor is turned off, the linear part of the outer periphery of the polygonal part and the linear part of the spring member are provided. And the adjacent two sides of the polygonal part and the dogleg of the spring member having a dogleg-shaped cross-sectional shape to stop the magnetic head mounted on the carriage at a predetermined position. Is characterized by.

[Operation] In the present invention, the rotary shaft is provided with a polygonal portion, and the housing is provided with a spring member that engages with the polygonal portion, so that the stationary position of the rotary shaft is mechanically controlled. ing.

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 source of the stepping motor is turned off.

As a result, when waiting for information reading and writing,
It becomes possible to turn off the power of the stepping motor,
The power consumption of the floppy disk device can be reduced.

[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 an embodiment of the present invention, FIG. 1 is a side view, and FIG. 2 is a sectional view showing a section taken along line II of FIG. is there. Hereinafter, description will be given by alternately referring to FIG. 1 and FIG.

The rotating shaft 28 of the stepping motor 10 is provided with a lead screw which is a spiral groove. The lead screw 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 rotational movement of the rotary shaft 28 by the function of the engaging element. Further, the bush 20 is press-fitted into the rotating shaft 28, and the yoke 12 made of a magnetic material is attached to the outer peripheral portion of the bush 20 and the magnet.
Fix 14 and. Further, the stator 18 in which the coil 16 is formed
Are arranged on the outer periphery of the magnet 14.

By doing so, the rotating shaft 28 for fixing the magnet 14
Can be rotated by a step angle proportional to the number of pulses input from the outside, and the magnetic head engaged with the lead screw can be linearly moved by a predetermined amount.

The stepping motor 10 is fixed to the housing 26, and the rotating shaft 28 is rotatably supported by a bearing 30 of the housing 26.

The rotary shaft 28 has a lead screw forming area and a housing 26.
In the meantime, a polygonal portion 22 having an angle number obtained by dividing 360 degrees by one step angle of the stepping motor 10 is provided. That is, if one step angle of the stepping motor 10 is, for example, 20 degrees, then 360 degrees / 20 degrees = 18, and an octagonal polygonal portion 22 is provided.

Further, the spring member 26 made of a leaf spring is fixed to the housing 26. Then, as shown in FIG. 2, the linear portion of the spring member 24 and the linear portion of the polygonal portion 22 are configured to engage with each other.

By engaging the polygonal portion 22 of the rotating shaft 28 and the spring member 24 in this way, when the power of the stepping motor is turned off, the rotating shaft 28 is stopped at a predetermined position, The magnetic head can be positioned by mechanical engagement between the polygonal portion 22 and the spring member 24.

Therefore, the phenomenon that the position of the magnetic head becomes uncertain due to a small index torque and a 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 with respect to the floppy disk does not shift by a dimension corresponding to at least one step angle. Hysteresis due to the difference does not occur.

As a result, even if the power of the stepping motor 10 is turned off,
Since the magnetic head is stopped at a predetermined position, it is possible to turn off the power of the stepping motor 10 while waiting for reading and writing. Therefore, low power consumption of the floppy disk device can be achieved.

The strength of the spring of the spring member 24 that engages with the polygonal portion 22 of the rotary shaft 28 is set to about 10% of the rotation torque of the stepping motor 10. This does not adversely affect the rotation of the stepping motor 10. Further, a solenoid having a power source that works in tandem with the power source of the stepping motor 10 is provided in the housing 26, and at the time of reading and writing, that is, when the rotary shaft 28 rotates, the polygonal portion 22 and the spring member 24 are utilized by utilizing the magnetic attraction of the solenoid. May be configured to be disengaged.

Further, the engagement between the rotary shaft 28 and the polygonal portion 22 has been described in the embodiment in which the linear portion of the polygonal portion 22 and the linear portion of the spring member 24 are engaged. It may be formed in a V shape so that two adjacent sides of the polygonal portion 22 and the dogleg portion of the spring member 24 are engaged with each other.

Furthermore, if the polygonal part 22 has an even number of angles,
The spring member 24 may be configured to engage not only on one side of the polygonal portion 22 but also on both sides of the polygonal portion 22.

Further, although the polygonal portion 22 has been described in the embodiment formed on the rotary shaft 28, a polygonal portion is formed on the outer peripheral portion of a member different from the rotary shaft 28, and the polygonal portion is formed on the rotary shaft 28. The member may be fixed.

The lead screw type has been described above, but 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, a polygonal portion is provided on the rotating shaft of the stepping motor, and the polygonal portion is configured to engage with the spring member. For this reason, the magnetic head is not displaced when the power of the stepping motor is turned off.

As a result, when waiting for information reading and writing,
It becomes possible to turn off the power of the stepping motor,
The current consumption of the floppy disk device can be reduced. 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 according to an embodiment of the present invention, FIG. 1 is a side view, and FIG. 2 is a sectional view showing a section taken along line II in FIG. 22 …… Polygonal part, 24 …… Spring member, 28 …… Rotation axis.

Claims (1)

[Scope of utility model registration request] 1. A stepping motor for a floppy disk device having a rotating shaft (28) and a spring member (24), wherein the rotating shaft (28) has a spiral groove for moving a carriage, and a stepping motor. It has a polygonal part (22) with an angle number obtained by dividing 360 degrees by one step angle of the motor (10), and the spiral groove and the engaging element engage with each other to rotate the rotary shaft (28). Converted to linear motion of the magnetic head mounted on the carriage, the spring member (24) is fixed near the spiral groove of the rotating shaft (28), and when the power of the stepping motor (10) is cut off, the polygonal part (22) A stepping motor for a floppy disk device in which the outer peripheral part of () elastically engages with the spring member (24) to stop the magnetic head at a predetermined position.