JP3341743B2 - Head carriage latch mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head carriage latch mechanism suitable for use in a portable personal computer or the like.

[0002]

2. Description of the Related Art In general, a magnetic disk drive frequently used in a portable personal computer or the like is required to have an impact resistance because it is necessary to protect a head and a recording medium (disk) from an impact due to a drop or the like. You.

In particular, in recent magnetic disk devices, it is required that the head be as close to the recording medium as possible during operation in accordance with the increase in recording density. For this reason, for example, the smoothness of the recording medium is increased. .

In such a magnetic disk drive,
If the head is positioned on the disk (data area) when the rotation of the disk is stopped (non-operation), it will be sucked and the disk cannot be started immediately again. They need to be evacuated.

In such a head retracting method, a CSS (contac) for retracting the head to the innermost peripheral portion of the disk is used.
t start stop) method and a ramp load method of retracting to the outermost position of the disk.

[0006] Among them, the CSS method is a method in which a protrusion is provided at a retracted position on a disk or a concave groove is provided, and suction is avoided by using a zone texture medium that reduces the smoothness only in this portion. It is. On the other hand, the ramp load method is a method in which a load bar is provided at the tip of a suspension holding a head, and the load bar rides on a ramp, thereby avoiding adsorption of the head to a disk.

In each of these systems, when the head carriage is moved from the carriage retreat position by an impact or the like, the head is attracted to the disk, so that the head carriage does not move from the retreat position even when an impact or the like is applied. Is important for the magnetic disk drive.

As such a mechanism, a head carriage is attracted by a magnet and released by a driving force of an actuator, or the head carriage is attracted by a spring member or a magnet, and the attracted state is determined by a spindle motor. There is one that is released by the wind force by the drive of.

However, in the mechanism using the actuator drive release method, it is necessary to make the carriage suction force lower than the actuator drive force and larger than the external impact force, and it is difficult to obtain such a carriage suction force. there were. Also, in this type of mechanism, it is necessary to avoid damage due to the contact of the head with the disk.
The load speed of the head is important, but it has been difficult to make the driving force of the actuator larger than the carriage suction force and to control the load speed of the head.

On the other hand, in the mechanism using the spindle motor drive release system, sufficient wind power cannot be obtained when the rotation speed of the spindle motor is low or when the disk diameter (3.5 inches or less) is small.

A mechanism for preventing the head carriage from moving from the retracted position due to an impact or the like is shown in FIG.
There is an inertia latch mechanism as shown in FIGS. 7 (a) to 7 (c) or FIGS. 7 (a) and 7 (b). These latch mechanisms will be described with reference to the drawings. First, FIGS. 6 (a) to 6 (c)
When the latch mechanism shown in FIG. 2A is described, the latch member 61 and the head carriage 62 at the positions shown in FIG. 2A receive an impact force from the outside, and as shown in FIG. When a rotational acceleration is generated in the carriage 62 in a direction away from the stopper 63 (counterclockwise) and a rotational acceleration is also generated in the latch member 61 in the counterclockwise direction, the head carriage 62 is locked by the latch member 61.

In this case, when a clockwise rotational acceleration is generated by an impact on the latch member 61 and the head carriage 62 as shown in FIG.
2 collides with the stopper 63 and rotates counterclockwise and is not locked by the latch member 61, so that the reliability is reduced.

Next, the latch mechanism shown in FIGS. 7 (a) and 7 (b) will be described. This latch mechanism can be applied to the latch member 71 and the head carriage 72 even when rotational acceleration is generated in any direction due to an impact. Function as a latch mechanism, but the head carriage 7
Since the notch for locking the lock member 2 is formed, the turning radius of the latch member 71 cannot be set to a sufficient size by this notch, and the latch member 71 is operated at a higher speed than the head carriage 72. I couldn't do that.

Therefore, when a rotational acceleration is applied to the latch member and the head carriage in either the clockwise or counterclockwise direction, the latch member functions as a latch mechanism and the latch member operates at a higher speed than the head carriage.
A latch mechanism as shown in FIG. The main latch member 81 which rotates by receiving rotational acceleration due to an external impact and the pressing (locking) of the main latch member 81 (claw portions 81a, 81b) rotate to lock the head carriage 82. A sub-latch member 83 is provided.

In the thus constructed latch mechanism, the main latch member 81 at the position shown in FIG.
As shown in FIG. 3B, when a counterclockwise rotational acceleration is generated by an external impact on the head carriage 82, the claw 81a of the main latch member 81 locks the sub-latch member 83, and the sub-latch member 83 is disengaged. The head carriage 8 is rotated counterclockwise to rotate counterclockwise.
2 is locked by the claw portion 83a.

As shown in FIG. 3C, when a clockwise rotational acceleration is generated by an external impact on the main latch member 81 and the head carriage 82, the claw portion 81b of the main latch member 81 is moved to the sub-latch member 83. To rotate the sub-latch member 83 counterclockwise,
The claw portion 83a locks the head carriage 82 that rotates counterclockwise by colliding with the stopper 84.

[0017]

However, in the conventional latch mechanism, since the head carriage 82 is locked by the main latch member 81 or the sub-latch member 83, not only two latch members are required, A shaft for rotating and supporting each of the latch members and a component (spring, magnet) for returning each of the latch members to the neutral position are required. As a result, there is a problem that the number of parts increases and the cost increases.

In this type of latch mechanism, the main latch member 81 rotates when the mechanism operates, and the sub-latch member 82 rotates to lock the head carriage 83 with this rotation operation. In addition, a high positional accuracy is required at the time of assembling the mechanism, and there is a problem that the assembling work is complicated.

Japanese Unexamined Patent Publication No. Hei 7-220414 discloses a "disk file device" capable of achieving a reduction in size and obtaining a sufficient locking force. There is no mention.

The present invention has been made in view of such circumstances, and it is possible to reduce the number of parts, relax the positional accuracy at the time of assembling the mechanism, and thereby reduce the cost and the assembly work. It is an object of the present invention to provide a head carriage latch mechanism that can be simplified.

[0021]

According to a first aspect of the present invention, there is provided a head carriage latch mechanism which rotates between two positions including a carriage retreat position. A latch member having a claw capable of locking the head carriage and having a rotating arm for receiving a returning force to a rotating neutral position, wherein a notch through which the claw of the latch member is inserted in the carriage retracting state is provided. Provided on the carriage, this notch
An opening is formed to release the claw in the direction opposite to the direction in which the head carriage rotates in the rotation neutral position of the latch member, and the latch member rotates from the rotation neutral position and the head carriage moves from the carriage retract position. The cutout surface is formed as a receiving surface such that the claw portion comes into contact with the rotation of the notch.

Therefore, when the head carriage is rotated at the rotation neutral position of the latch member, the opening of the notch releases the claw in the direction opposite to the carriage rotation direction.
On the other hand, when the head carriage at the carriage retreat position and the latch member at the rotation neutral position rotate together, the latch member locks the head carriage by the contact of the claw portions with the cutout surfaces.

According to a second aspect of the present invention, in the head carriage latch mechanism according to the first aspect, the rotation center of the latch member and the center of gravity coincide with each other. Therefore, the latch member rotates in a balanced state by the coincidence between the center of rotation and the center of gravity.

The invention according to claim 3 is the invention according to claim 1 or 2
In the latch mechanism of the head carriage, wherein in the retracted position of the rotation neutral position and the head carriage of the latch member, the dimensions of the to the inner surface dimensions and opening up to the cutout surface from the claw portions respectively and G _I and G _C with, when the dimension from the claw portion to the rotational center of the dimensions and the head carriage to the center of rotation of the latch member, respectively, and R _I and R _C, each of these dimensions _{G I × R I> G C} × R C
Are set to dimensions satisfying the following inequality. Therefore, when the head carriage at the carriage retract position and the latch member at the pivot neutral position both rotate at the pivoting neutral position of the latch member and the retracted position of the head carriage, the claw inside the notch moves out of the notch. Abuts the notch without any contact.

According to a fourth aspect of the present invention, in the head carriage latch mechanism of the first, second, or third aspect, the contact surface of the claw portion and the notch surface of the notch share a rotation center of the latch member. A curved surface having a common radius as a center and a dimension from the common center to a contact position in the latch member / carriage contact state is provided. Therefore, when the claw portion comes into contact with the notch surface, this contact force acts as a reaction force in a direction passing through the rotation center of the latch member.

According to a fifth aspect of the present invention, in the head carriage latch mechanism according to any one of the first to fourth aspects, a guide surface for guiding the claw portion into the notch is formed in the opening. is there. Therefore, when the claw portion of the latch member at the rotation neutral position is displaced into the notch from outside the notch of the head carriage, the claw portion is guided by the guide surface.

According to a sixth aspect of the present invention, in the head carriage latch mechanism according to any one of the first to fifth aspects, the inner surface of the opening has a radius of curvature centered on the center of rotation of the head carriage. It is configured to have a curved surface. Therefore, when the head carriage is rotated at the rotation neutral position of the latch member, the claw is displaced inside and outside the notch along the inner surface of the opening along with this rotation.

According to a seventh aspect of the present invention, in the head carriage latch mechanism according to any one of the first to sixth aspects, a stopper of the head carriage is arranged on a shaft that pivotally supports the latch member. is there. Therefore, the shaft of the latch member doubles as a stopper of the head carriage.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a plan view for explaining a case in which a latch mechanism of a head carriage according to a first embodiment of the present invention is used in a magnetic disk drive.
FIGS. 2A and 2B are a plan view and a side view showing an arrangement state of a latch member and a head carriage in the latch mechanism of the head carriage according to the first embodiment of the present invention, and FIG. FIG. 4 is an enlarged plan view illustrating a main part of a latch mechanism of the head carriage according to the embodiment. 1 to 3, the magnetic disk drive indicated by reference numeral 1 includes a base 2, a voice coil motor (VCM) 3, a latch mechanism 4, and a head carriage 5.

The base 2 forms a housing (not shown) for a magnetic disk drive together with a cover (not shown), and is formed of a box having a substantially square planar shape that opens upward. The recording medium D is provided in the base 2 at a predetermined rotation speed.
And a ramp-equipped ramp 7 serving as a load bar riding member in a carriage retracting state (read / write ending state).

In the base 2, stoppers 8, 9 located at two positions in the rotation direction of the head carriage 5 are provided. The stopper 8 is made of a cushioning member such as rubber, and is attached to a distal end portion of a shaft (described later) serving as a rotation center of the latch member 13. This functions when the magnetic head 5a moves to the innermost peripheral position of the recording medium D by the rotation of the head carriage 5, and the suspension (described later) contacts the clamp ring C and the spacer ring (not shown). Breakage is prevented. The stopper 9 is made of a magnet or the like, and functions when the magnetic head 5a is moved to the outermost peripheral position (carriage retreat position) by the rotation of the head carriage 5, so that the head carriage 5 comes off from the ramp 7 or the suspension base 2 is moved. The occurrence of damage due to contact with the storage components in the interior is prevented.

The VCM 3 includes a coil 10, a yoke 11, and a magnet 12, and is disposed in the base 2. The coil 10 is mounted on a coil holder 13 integrated with the head carriage 5. The yoke 11 includes two upper and lower yokes (only the lower yoke is shown), and is mounted in the base 2. The magnet 12 comprises two magnets, upper and lower (only the lower magnet is shown),
Each is fixed to the upper and lower yokes 11 so as to sandwich the coil 10.

The latch mechanism 4 has a latch member 13. The latch member 13 is composed of a rotating arm having a substantially U-shape in a plane, is disposed below the head carriage 5, and is rotatably supported in the base 2 via a shaft 14 at an intermediate portion thereof. At one end of the latch member 13, a claw portion 15 capable of locking the head carriage 5 is provided, and at the other end, a shaft 14 (latch member 13) is provided.
A counterweight 16 for matching the center of gravity of the rotation with the center of gravity is attached. In the vicinity of the center of rotation of the latch member 13, a convex piece 13a protruding in the radial direction is provided integrally. A magnetic body (not shown) such as SUS430 that receives an attractive force by the magnet 12 of the VCM 13 is attached to the convex piece 13a. As a result, a return force to the rotation neutral position is constantly applied to the latch member 13, and the latch member 13 is positioned at the rotation neutral position when no external impact force is received.

The head carriage 5 is rotatably supported in the base 2 via a pivot bearing 17, and is entirely formed of a synthetic resin having a substantially fan-shaped rotating arm in a plane. As a result, the head carriage 5 rotates between the stoppers 8 and 9 by the VCM 3. A magnetic head 5 is provided at one end of the head carriage 5.
A suspension 18 that holds a is mounted, and a load bar 19 that rides on the ramp 7 (slope) in a retracted state of the carriage is attached to the tip of the suspension 18. At the other end of the head carriage 5, stopper stoppers 20 corresponding to the stoppers 8 and 9 are integrally provided so as to protrude in the carriage surface direction. The receiving surface 20b of the two receiving surfaces 20a and 20b of the stopper receiver 20 has a SUS4
A magnetic body (not shown) made of 30 is attached.

In the vicinity of the stopper receiving portion of the head carriage 5, a notch 21 through which the claw portion 15 of the latch member 13 is inserted in the retracted state of the carriage is provided. The notch 21 has an opening 21 a for allowing the claw portion 15 to escape in a direction opposite to the rotation direction of the head carriage 5 at the rotation neutral position of the latch member 13. Further, the notch 21 has a notch surface 21b on which the claw portion 15 comes into contact by the rotation of the latch member 13 from the rotation neutral position and the rotation of the head carriage 5 from the carriage retreat position.
Is formed.

[0036] Then, keep turning neutral position of the retreat position and the latch member 13 of the head carriage 5 as shown in FIG. 3, to the inner surface 21a ₁ of the dimensions and the opening 21a to the notch surface 21b from the claw portion 15 with a G _I and G _C dimensions, respectively, the dimensions of the claw portion 15 to the rotation center a of the latch member 13 the center of rotation of the dimensions and the head carriage 5 to (the shaft 14) B (pivot bearing 17), respectively When R _I and _{R C,} each of these dimensions are set to a dimension which satisfies the inequality _{G I × R I> G C} × R C.

Here, it is proved that the inequality G _I × R _I > G _C × _RC holds. To satisfy this inequality,
When the claw portion 15 of the latch member 13 at the pivot neutral position by an external impact is assumed to abut the to the inner surface 21a ₁ of the opening 21a, cut a claw portion 13 away surface 21
It is sufficient that a gap is formed between the gap and b.

That is, assuming that the angular velocity of the latch member 13 and the head carriage 5 is θ radians / sec, the opening 2 is formed from the claw 15 of the latch member 13 at the rotation neutral position.
The rotation amount _{R I} × dimensioned GC to the inner surface 21a ₁ of 1a
dimensional difference between θ _G C -R _I × θ is _{G C -R I × θ = 0} ...
And the latch member 1 also in the rotation neutral position.
Size difference to the notch surface 21b from third claw portion 15 of the dimension _{G I} and the rotation amount _{R C × θ G I -R C} × θ is _G I -R
Since _C × θ> 0 ... and may if they, by erasing the theta from _{equation, G I × R I> G} C × R C is obtained.

In this case, it is assumed that the head carriage 5 and the latch member 13 rotate at the same angular velocity, assuming that the rotational acceleration due to an externally applied impact is sufficiently large and no external force such as friction acts.

Thus, when the head carriage 5 at the carriage retract position and the latch member 13 at the pivot neutral position rotate together at the pivoting neutral position of the latch member 13 and the retracted position of the head carriage 5, the notch 21
The inner claw portion 15 abuts on the notch surface 21b without moving out of the notch 21, and the head carriage 5 and the latch member 13 are mutually restricted from rotating.

When the latch member 13 and the head carriage 5 are in the rotation neutral position and the retracted position of the head carriage 5, respectively, the magnetic force of the magnet 12 and the frictional force on the shaft 14 act on the latch member 13 to cause the head carriage 5 to move. The magnetic force of the stopper 9, the frictional force between the ramp 7 and the load bar 19, and the frictional force of the pivot bearing 17 act on the head carriage 5. The external force acting on the head carriage 5 acts on the latch member 13 as the external force increases. ,
Since the angular velocity of the latch member 13 becomes higher than the angular velocity of the head carriage 5, the strength of the magnetic force is set so that these angular velocities become the same angular velocity.

The notch surface 21a of the notch 21 and the abutment surface 15a of the claw portion 15 have the rotation center (shaft 14) of the latch member 13 as a common center. It is formed by a curved surface having a common radius as a dimension up to the contact position in the state. Thus, when the claw portion 15 comes into contact with the notch surface 21b, the reaction force of this contact force acts in a direction passing through the center of rotation of the latch member 13, and the rotation of the latch member 13 due to the rotation of the head carriage 5 Operation is blocked.

The opening 21a of the notch 21 has a claw 1
A guide surface 21a ₂ (tapered surface) is formed to guide 5 from the outside of the notch 21 to the inside of the notch 21. As a result, the claw portion 15 of the latch member 13 at the rotation neutral position causes the notch 21
Guide surface 21a when displacing into notch 21 from outside
₂ , the head carriage 5 is smoothly rotated.

The inner surface 21a of the opening portion 21a ₁ is formed by a curved surface having a radius of curvature of the center of rotation of the head carriage and the center of curvature. Thereby, when the head carriage 5 rotates in the rotation neutral position of the latch member 13,
The claw portion 15 with the rotation operation is displaced along the inside and outside of the notch 21 on the inner surface 21a ₁ of the opening 21a.

Next, the head carriage according to the present embodiment will be described.
The operation of the latch mechanism will be described with reference to FIGS.
explain. 4 and 5 relate to the first embodiment of the present invention.
Operating states of the latch mechanism of the moving head carriage
It is a top view showing a state. First, the base 2 (housing)
When a rotational acceleration due to a clockwise impact force acts from
This will be described with reference to FIG. That is, when
When the impulse force acts in the measuring direction, arrows a and b show in FIG.
Member 13 and carriage in the rotation neutral position
The head carriage 5 at the retracted position rotates counterclockwise,
With this rotation, the claw portion 15 is moved to the notch surface 21b. ₁To
The latch member 13 and the head carriage 5
The rotation is restricted.

Next, in the case where a rotational acceleration due to a counterclockwise impact force acts on the base 2 (housing) from the outside,
This will be described with reference to FIG. That is, when an impact force in the counterclockwise direction acts from the outside, the latch member 13 at the rotation neutral position rotates clockwise as shown by an arrow c in FIG. After the head carriage 5 at the retracted position is rotated clockwise, a reaction force is generated by the contact of the stopper receiver 20 (receiving surface 20b) with the stopper 9 (shown in FIG. 1) as shown by an arrow e in FIG. rotated clockwise, the pawl portion 15 is notched surface 21b ₂ in contact with the latch member 13 and the head carriage 5 is rotated restricted to one another. Thus, the latch member (claw)
Locks the head carriage (notched surface) to prevent the head carriage from dropping from the carriage retreat position (ramp 7) due to the impact force.

In this case, when the impact force stops acting, the latch member 13 and the head carriage 5 are attracted by the magnet 12 and the stopper 9, respectively, and return to the rotation neutral position and the retracted position to the carriage. The latch member 13
When the head carriage 5 rotates between the stoppers 8 and 9 at the rotation neutral position of
a releases the claw portion 15 in the direction opposite to the rotation direction of the head carriage 5.

Therefore, in this embodiment, since the head carriage 5 is locked by the latch member 13, the latch mechanism can be constituted by a single latch member, and the number of parts can be reduced. . Also,
In the present embodiment, the latch member 13 rotates to lock the head carriage 5, and the latch member 13 and the head carriage 5 are both disposed on the base 2 as a common attachment reference member. Positional accuracy can be reduced during assembly of the mechanism.

In this embodiment, the case where the present invention is applied to a magnetic disk device has been described. However, the present invention is not limited to this, and can be applied to a magneto-optical disk device or an optical disk device in the same manner as the embodiment. is there.

[0050]

As described above, according to the present invention, when the head carriage is rotated in the rotation neutral position of the latch member, the notch opening allows the claw portion to escape in the direction opposite to the carriage rotation direction. . On the other hand, when the head carriage at the carriage retreat position and the latch member at the rotation neutral position rotate together, the latch member locks the head carriage by the contact of the claw portions with the cutout surfaces. Therefore,
Since the latch mechanism can be constituted by a single latch member, the number of parts can be reduced, and the positional accuracy can be reduced at the time of assembling the mechanism, thereby reducing costs and simplifying assembly work. be able to.

[Brief description of the drawings]

FIG. 1 is a plan view for explaining a case where a latch mechanism of a head carriage according to a first embodiment of the present invention is used in a magnetic disk drive.

FIGS. 2A and 2B are a plan view and a side view showing an arrangement state of a latch member and a head carriage in a head carriage latch mechanism according to the first embodiment of the present invention.

FIG. 3 is an enlarged plan view showing a main part of a latch mechanism of the head carriage according to the first embodiment of the present invention.

FIG. 4 is a plan view showing an operation state when an impact force is applied clockwise in the latch mechanism of the head carriage according to the first embodiment of the present invention.

FIG. 5 is a plan view showing an operation state when an impact force is applied in a counterclockwise direction in the head carriage latch mechanism according to the first embodiment of the present invention.

6 (a) to 6 (c) are plan views showing a conventional head carriage latch mechanism (1).

FIGS. 7A and 7B are plan views showing a conventional head carriage latch mechanism (2).

8A to 8C are plan views showing a conventional head carriage latch mechanism (3).

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Magnetic disk drive 2 Base 3 Voice coil motor (VCM) 4 Latch mechanism 5 Head carriage 6 Spindle motor 7 Lamp 8,9 Stopper 10 Coil 11 Yoke 12 Magnet 13 Latch member 14 Shaft 15 Claw part 15a Contact surface 16 Counter weight 17 pivot bearing 18 suspension 19 load bar 20 stopper receiving 21 cutout 21a opening 21b, 21b _1, 21b ₂ notched face 21a ₁ inner surface

Claims (7)

(57) [Claims] A latch mechanism for a head carriage that pivots between two positions including a carriage retreat position, wherein the latch mechanism has a claw that can lock the head carriage and receives a return force to a rotation neutral position. The head carriage is provided with a notch through which a claw portion of the latch member is inserted in a retracted state of the carriage. The notch is provided with a notch for turning the head carriage at a rotation neutral position of the latch member. An opening is formed in the direction opposite to the moving direction to release the claw portion, and the claw portion is abutted by the rotation of the latch member from the rotation neutral position and the rotation of the head carriage from the carriage retreat position. A latch mechanism for a head carriage, wherein a notch surface is formed so as to be in contact with the head carriage. 2. The head carriage latch mechanism according to claim 1, wherein the center of rotation of the latch member coincides with the center of gravity. 3. The size from the claw portion to the cutout surface and the size from the inner surface of the opening to G _I and G _{C at} the rotation neutral position of the latch member and the retracted position of the head carriage, respectively. Assuming that the dimension from the claw to the center of rotation of the latch member and the dimension from the center of rotation of the head carriage are R _I and R _C , these dimensions are G _I × R _I > G _C × 3. The head carriage latch mechanism according to claim 1, wherein the dimensions are set to satisfy _RC inequality. 4. A contact surface of the claw portion and a notch surface of the notch have a common center around a rotation center of the latch member, and extend from the common center to a contact position in a latch member / carriage contact state. 4. A latch mechanism for a head carriage according to claim 1, wherein the dimension is a curved surface having a common radius. 5. The head carriage latch mechanism according to claim 1, wherein a guide surface for guiding the claw portion into the notch is formed in the opening. 6. The head according to claim 1, wherein the inner surface of the opening is formed as a curved surface having a radius of curvature whose center is the center of rotation of the head carriage. Carriage latch mechanism. 7. A head carriage latch mechanism according to claim 1, wherein a stopper of said head carriage is arranged on a shaft which rotatably supports said latch member.