JP3351603B2 - Latch actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head latch mechanism for a small magnetic disk drive.

[0002]

2. Description of the Related Art Conventionally, as a latch mechanism of this type, a double-latch type solenoid is used in a large magnetic disk drive, and a latch magnet and an iron plate disposed at an end of a driving coil are used in a small magnetic disk drive. It was latched by magnetic attraction. However, in a microminiature magnetic disk drive, one of its uses is that when the magnetic disk drive is mounted on a portable personal computer, the impact force applied to the magnetic disk drive in the rotating direction and the like becomes large, and the conventional magnetic disk drive has been about 300G. , 500 G, and in order to overcome this impact force and latch, it is required that the latch force be larger than that of the conventional system. Therefore, it is necessary to increase the attraction force. However, if the attraction force is increased, the shape of the voice coil motor is reduced, so that it is difficult to release the latch with the torque generated by itself. In addition, by increasing the latch force, there is a problem of dust generation due to collision at the time of adsorption between the iron plate for adsorption and the magnet for latch.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to increase the latching force so that the magnetic head can reliably latch against the impact force of the microminiature magnetic disk device in the rotating direction and the like. Another object of the present invention is to provide a latch actuator which can release the latch by the torque of the voice coil itself and solve the problem of dust generation at the time of latch.

[0004]

According to the present invention, there is provided a solenoid having a drive unit connected to a magnetic circuit opposed to a suction iron plate provided at an end of a drive coil of a voice coil motor via a predetermined space. The magnetic circuit comprises a permanent magnet for latching, and a holder which encloses the permanent magnet and has a stopper formed by extending a bottom portion, and the driving portion has a bent portion at one end and a bent portion at the other end. A solenoid yoke in which a storage portion is formed, a fixed core disposed in the storage portion, and a movable core in which a front end portion protrudes from the storage portion and is connected to the magnetic circuit, and a rear end portion is combined with the fixed core. An exciting coil disposed on the outer periphery of the fixed iron core and the movable iron core in the storage part, and a spring wound between the holder and the storage part at a tip end of the movable iron core, the elasticity of the spring And the said By the stopper function of the magnetic circuit in the direction of the iron plate by the topper portion and the bent portion, the iron plate and the magnetic circuit are kept in a latched state with a fixed interval, the movable iron core is retracted, and the permanent magnet is moved. A latch actuator which is configured to be in an unlatched state by increasing a distance between the latch actuator and the iron plate. That is, a drive unit for driving a latch magnetic circuit is provided, a magnetic circuit for latch is connected to a tip of a movable iron core constituting the drive unit, a spring is arranged on the movable iron core, and a solenoid yoke surrounding the movable iron core is provided. The tip of the extension that extends the bottom of the spring toward the magnetic circuit side in the axial direction of the movable core is bent, and this bent portion functions as a stopper that engages with the holder of the magnetic circuit for latching, and the extension force of the spring wound around the movable core Then, the latching magnetic circuit is pressed through the holder to the preceding stopper to bring it close to the iron plate attached to the end of the drive coil of the voice coil, thereby maintaining a constant distance. In this proximity state, the iron plate attached to the end of the drive coil and the magnetic circuit for latching are latched by the attractive force. Thus, the iron plate and the latch magnetic circuit are brought into the latch state without contact. In latch release,
A voltage is applied to the excitation coil provided in the solenoid, and the movable core moves in the opposite direction to the magnetic circuit side (retreat)
Then, as the distance between the latched magnetic circuit and the iron plate arranged on the drive coil increases, the attraction force is attenuated. Thereby, the latch can be released by the torque force of the voice coil motor itself.

[0005]

A latch magnetic circuit is arranged so as to be opposed to an iron plate attached to the voice coil motor side, and the latch magnetic circuit is latched close to the iron plate and released away from the iron plate to release the latch. Are connected and arranged with a drive unit having a movable iron core for moving forward and backward. The latching magnetic circuit keeps the distance from the iron plate attached to the voice coil motor side at a constant distance even when the latch is performed, while the latching magnetic circuit connects the iron plate on the voice coil motor side to the latching magnetic circuit when the latch is released. The gap is widened by the retreat of the movable core, so that the latch attraction force is weakened so that the drive coil can release the force by itself. Further, with such a mechanism, the iron plate for latch attraction and the magnetic circuit for latch do not come into contact with each other, so that dust generation due to contact does not occur.

[0006]

1 and 2 show the appearance of a latch actuator according to the present invention, together with a driving coil end of a voice coil motor on which an iron plate is arranged.

FIG. 1 shows a latch state, in which a latch attraction iron plate 1 attracts a latch magnetic circuit composed of a yoke 2, a latch permanent magnet 3, a yoke 2 and a holder 4 holding the permanent magnet 3. Latched. The distance between the iron plate 1 disposed at the end of the drive coil 19 and the magnetic circuit is 0,0.
A non-contact type in which the iron plate and the magnetic circuit do not directly contact each other is set to 2 to 0.5 mm. In order to maintain this distance, the bottom of the solenoid yoke 5 surrounding the movable iron core 7, the exciting coil 8 and the fixed iron core 9 by the storage part 5a is bent at the end extending toward the magnetic circuit side to form a solenoid yoke tip bent part 51, The magnetic circuit is bent through the stopper portion 41 through the stopper portion 41 so as to engage with the stopper portion 41 (which also functions as a damper) formed on the polyurethane holder 4 so that the spring 6 wound around the movable iron core 7 tends to expand. The closest distance between the fixed iron core 9 and the yoke 2 is determined by pressing the core 51 against the portion 51.

FIG. 2 shows an unlatched state of the latch actuator according to the present invention. A voltage is applied to the exciting coil 8, the movable core 7 is attracted to the fixed core 9, and the spring 6
The magnetic circuit composed of the yoke 2, the permanent magnet 3 and the holder 4 is separated from the closest distance to the iron plate 1, the attraction force to the iron plate is weakened, and the voice coil motor itself arranged as shown in FIG. The latch state of the drive coil 19 is released by the torque by itself. After the release, the exciting voltage of the exciting coil 8 is cut off, and the resilient force of the spring 6 arranged on the movable iron core 7 promptly holds the latch magnetic circuit again at the position determined by the bent portion 51 at the tip end of the solenoid yoke. .

According to the present invention, the latch can be released by the own torque of the voice coil motor while increasing the latch force of the drive coil.

A latch actuator comprising a magnetic circuit and a drive unit according to the present invention can be applied to a latch of an optical pickup of a magneto-optical disk.

[0011]

As described above, according to the present invention, by increasing the holding force of the latch of the magnetic head drive coil of the ultra-small magnetic disk, even if the magnetic disk is subjected to an impact force in the rotational direction or the like, it is possible to reduce the impact force. It has become possible to provide a latch actuator which can be reliably latched against an impact force and released on the other hand by the voice coil motor by itself.
Further, even in the latch state, the attracting iron plate on the voice coil motor side does not contact the magnet on the latch actuator side, so that the problem of dust generation can be solved.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing a state when a latch actuator according to the present invention is latched.

FIG. 2 is an external perspective view showing a state of the latch actuator according to the present invention when the latch is released.

FIG. 3 is a diagram showing a part of a conventional magnetic disk and a voice coil motor of a head positioner. FIG. 3A is a partially crushed view of the voice coil motor. FIG. 3B is a cross-sectional view from the direction of arrow A in FIG.

[Explanation of symbols]

 Reference Signs List 1 Iron plate (for latch attraction) 2 Yoke (for magnetic circuit for latch) 3 Permanent magnet (for latch) 4 Holder (for magnetic circuit) 41 Stopper part (for holder) 5 (Solenoid) yoke 5a Storage part 51 Bend of solenoid yoke tip Part 6 Spring (wrapped around movable core) 7 Movable core 8 Exciting coil 9 Fixed core 11 Iron plate (for latch attraction) 12 Carriage (with drive coil) 13 Cover yoke (of voice coil motor) 14 Bearing assay 15 Magnetic head 16 Magnetic disk 17 Base yoke (of voice coil motor) 18 Permanent magnet (of voice coil motor) 19 Drive coil 20 (Polyurethane) damper 21 Permanent magnet for latch attraction

Claims (1)

(57) [Claims] 1. A solenoid having a drive unit connected to a magnetic circuit opposed to a suction iron plate provided at an end portion of a drive coil of a voice coil motor via a predetermined space portion, wherein the magnetic circuit comprises a latch circuit. A solenoid yoke having a permanent magnet and a holder having a stopper portion formed by extending the bottom portion and enclosing the permanent magnet, wherein the driving portion has a bent portion at one end and a storage portion at the other end; And a fixed core disposed in the storage portion, a movable core having a front end protruding from the storage portion and connected to the magnetic circuit, and a rear end combined with the fixed core; and the fixed portion in the storage portion. An exciting coil disposed on the outer periphery of the iron core and the movable iron core; and a spring wound between the holder and the housing at the tip end of the movable iron core. The elasticity of the spring, the stopper part, and the bending Department By the stopper function of the magnetic circuit in the direction of the iron plate, the iron plate and the magnetic circuit are in a latch state while maintaining a constant distance, the movable iron core is retracted, and the distance between the permanent magnet and the iron plate is reduced. Wherein the latch actuator is configured to open to be in an unlatched state.