HK1069476B - Disk drive - Google Patents

Description

Disk device

Technical Field

The present invention relates to a signal conversion element swing arm for a disk device such as a magnetic disk device, an optical disk device, and a magneto-optical disk device, which includes a floating signal conversion element such as a magnetic head or an optical head, and more particularly to an actuator holding device provided with the signal conversion element swing arm when the signal conversion element swing arm is at a retracted position during unloading in a non-operating state, and a disk device using the same.

Background

When the disk device stops operating, a signal conversion element swing arm (hereinafter simply referred to as a swing arm) carrying a signal conversion element is unloaded from an area where data is recorded, moved to a predetermined area (パ - キングゾ - ン, stop area) on the recording medium and held, or moved to a predetermined position in the vicinity of the outer periphery of the recording medium where the signal conversion element does not contact the surface of the recording medium and held. That is, the swing arm is held at a predetermined retreat position when the disk device stops operating. Further, when an external impact is applied when the disk apparatus is stopped, the swing arm moves from the retracted position to the data recording area on the recording medium, and the surface of the data area on the recording medium is damaged by the collision between the signal conversion element and the surface of the recording medium, or when the swing arm moves to the data recording area, the swing arm holding mechanism or the clamping mechanism for holding or clamping the swing arm at a predetermined retracted position is employed so that the swing arm is brought into contact with the data recording area and the signal conversion element is slid to damage the surface of the data area on the recording medium, or the swing arm or the component is damaged by the collision between another component of the disk apparatus and the swing arm.

An example of a conventional disk device having a swing arm holding mechanism or a chucking mechanism will be described below.

First, for a disk storage device having a swing arm holding mechanism, the following structure is proposed: an iron piece is attached to an integrally provided projection on the other end side of an actuator arm having one end to which a transducer head (corresponding to the signal transducer) is attached and the other end to which a coil is attached, and is rotatable about a rotation shaft, thereby constituting a voice coil motor (hereinafter referred to as VCM) actuator (corresponding to the rocker arm); the actuator arm holding mechanism is constituted by an iron piece disposed on the actuator arm and a permanent magnet fixed to the housing.

In this configuration, when the disk storage apparatus is stopped, a current is supplied to the coil of the VCM to move the actuator arm to a predetermined retreat position, and when the disk storage apparatus approaches the predetermined retreat position, the iron piece is attracted by the permanent magnet to fix the actuator arm at the retreat position; in this state, even if an external force is applied, the actuator arm is fixed by the magnetic attraction force and does not move, and the data of the data recording area on the recording medium or the actuator is protected from the unexpected movement of the head or the actuator arm (see, for example, japanese patent registration nos. jp2803693, P3 and fig. 1).

Further, for a disk storage device having a swing arm clamp mechanism, the following structure is proposed: the actuator arm holding mechanism is provided with the same actuator arm holding mechanism as the above-mentioned example of the disk storage device having the rocker arm holding mechanism, and an actuator arm holding mechanism composed of a lock member and a solenoid is further provided, the actuator arm holding mechanism further has elasticity so as to be engaged with the VCM actuator in the up-down direction, and a plate spring having a stress in an upward direction moves up and down in accordance with the movement of the iron plunger caused by the supply of current to the solenoid, a magnet as a 1 st magnetic field supply member having a 1 st magnetic force is disposed under the plunger, a VCM yoke as a 2 nd magnetic field supply member having a 2 nd magnetic force is disposed on the upper side, and the solenoid generates a magnetic force for pushing up the plunger to move the plate spring to the upper side when a 1 st current is supplied thereto, when a 2 nd current different from the 1 st current is supplied, a magnetic force is generated to press the plunger, and the plate spring is moved to the lower side. Further, the 1 st magnetic force of the magnet having a downward magnetic force larger than the upward stress of the plate spring fixes the plate spring on the lower side, and the upward stress of the plate spring plus the 2 nd magnetic force of the VCM yoke attracts and fixes the plate spring on the upper side.

In this configuration, when the disk device is operated, the plunger is attracted by the 1 st magnetic force in the direction of the magnet, and the plunger further presses the leaf spring to the lower side to fix the leaf spring in the unlocked state, that is, to fix the leaf spring at a height that does not interfere with the movement of the actuator; when the disk device is stopped, the actuator is moved to a predetermined lock position (corresponding to the above-mentioned retreat position), and the 1 st current is supplied to the solenoid so as to generate an upward magnetic force larger than the difference between the magnitude of the 1 st magnetic force of the magnet and the magnitude of the stress of the leaf spring, and the leaf spring is moved in the upward direction so as to be fixed by moving the leaf spring, so that the locked state in which the leaf spring is fixed on the upper side is achieved. Here, the current is supplied to the solenoid only when the plate spring is shifted from the unlocked state to the locked state or from the locked state to the unlocked state, and the current is not supplied to the solenoid when the plate spring is in the unlocked state or the locked state fixed to the upper side or the lower side, respectively. When the disk device is stopped, the magnetic attraction force of the iron piece and the permanent magnet fixes the leaf spring to the upper side to be in the locked state and locks the actuator at the retreat position, thereby fixing the actuator not only in the horizontal direction but also in the vertical direction and preventing the actuator from moving by an impact (see, for example, japanese patent laid-open gazette nos. jp08-221915, P4, P5, fig. 1, 2, and 4).

Further, as another example of the disk storage device having the swing arm clamp mechanism, the following structure is proposed: the actuator is provided so as to be rotatable about a pivot shaft, and is composed of a head arm and a coil arm disposed on opposite sides of the pivot shaft. The disk device of this configuration has the following features.

(1) The head arm is composed of a transport arm and a suspension arm, the suspension arm has a projecting tongue forming a convex part for retreating into the ramp block, and a head slider carrying a signal conversion element is mounted near the projecting tongue.

(2) Further, the voice coil arm in which the voice coil is mounted is composed of an outer arm and an inner arm.

(3) The slope block and the inertia stopper mechanism provided at the retracted position of the actuator are accommodated in the sleeve.

(4) The slope block fixed in the sleeve by screws is provided with a plurality of slopes which are arranged from the side surface of the slope support in a protruding mode along the horizontal direction, and each slope is provided with a composite plane comprising a 1 st slope, a top plane, a 2 nd slope, a bottom plane and a 3 rd slope.

(5) The inertia stopper mechanism includes an inertia lever swingable about a swing axis, a stopper lever swingable about another swing axis, and a spring for holding the stopper lever at an arm release position, and the inertia moment of the inertia lever and the stopper lever around the respective swing axes is larger than the inertia moment of the stopper lever.

(6) The inertia lever has an inertia arm and a balance arm forming a 1 st engagement projection for engaging with the stopper lever at the 1 st engagement portion and a 2 nd engagement projection for engaging at the 2 nd engagement portion.

(7) The stopper lever has a stopper arm and an auxiliary arm forming 2 spring engaging protrusions engaged with an action-side end portion of the spring, a positioning protrusion for determining an actuator release position and an actuator stopping position of the stopper lever, and a stopper protrusion for engaging with a front end portion of an inner arm of the actuator to stop the actuator when the stopper lever is moved to the actuator stopping position.

(8) The ramp block and the inertial stop mechanism constitute an actuator locking mechanism.

In the configuration having these features, when the disk device is not operated, the actuator is unloaded to the retracted position, the projecting portion of the suspension arm is held on the bottom plane of the slope, and the projecting portion of the suspension arm rises up the 2 nd slope or the 3 rd slope of the slope to damp the swing energy of the head arm to suppress the movement of the head arm against a weak impact, and the head arm is prevented from moving from the retracted position to the disk side or the opposite side thereof, and functions as an actuator holding structure for holding the head arm at the retracted position. Further, in the operation of the inertia stopper mechanism in the case where an impact is applied to the disk device when the disk device is not in operation, when a torque for swinging the inertia stopper mechanism counterclockwise is applied to the actuator by an external impact, a torque for rotating the inertia lever and the stopper lever counterclockwise about the respective swing axes is applied to the inertia lever and the stopper lever, respectively, and if the torque applied to the inertia lever is larger than a resultant torque of a torque caused by the impact applied to the stopper lever and a torque of a spring for rotating the stopper lever clockwise about the swing axis, the inertia lever rotates counterclockwise regardless of the direction of the torque applied to the stopper lever, the stopper lever is pulled by the 1 st engaging projection at the 1 st engaging portion to swing the stopper lever counterclockwise, the stopper projection of the stopper arm engages with the front end portion of the inner arm moved from the retracted position, the actuator is stopped, and then the tab of the actuator is pressed back to the bottom plane of the slope by the action of the 2 nd slope of the slope, the engagement of the front end portion of the inner arm and the stopper projection is disengaged, and the stopper arm is returned to the actuator release position by the action of the spring. When an external impact applies a torque to the actuator to pivot the actuator clockwise, a torque to pivot the inertia lever and the stopper lever clockwise about the respective pivot shafts is applied to the inertia lever and the stopper lever, and a torque to pivot the stopper lever clockwise about the pivot shaft is always applied by a spring in addition to the torque due to the impact. On the 2 nd fitting part, if the torque acting on the inertia lever is larger than the resultant force of the torque caused by the impact acting on the stop lever and the torque caused by the spring, the 2 nd fitting projection presses the stop lever on the 2 nd fitting part to make the stop lever swing anticlockwise, the stop projection of the stop arm collides with the impact stopper formed by the elastic body for limiting the swing range of the actuator violently to be fitted with the front end part of the inner arm rebounded anticlockwise, and the actuator is stopped; in order to make the moment caused by the impact acting on the inertia lever larger than the moment acting on the stop lever, the inertia lever swings along the direction of the moment caused by the impact, and the moment of inertia of the inertia lever is set larger than that of the stop lever; in order to set the swing distance of the stopper protrusion from the release point to the stopper point, the position of the stopper point, the distance from the stopper protrusion to the swing shaft, and the like before the tip end portion of the inner arm moves from the retreat point to the stopper point, the actuator is stopped at the retreat position, and the actuator is locked to prevent the head arm and the head slider from entering the disk arrangement space (see, for example, japanese patent laid-open gazette No.10-302418, P4, P5, fig. 1 and 2; No.2002-206356, P5-6, fig. 1).

In the actuator holding mechanism for the disk storage device having the above-described conventional swing arm holding mechanism, however, when the disk storage device is stopped, the actuator arm is fixed at the retracted position of the actuator by the attraction force of the iron piece provided to the actuator arm and the permanent magnet fixed to the housing; in the actuator holding mechanism having such a configuration, although impact resistance against an impact in the same direction as the rotational direction of the actuator is relatively high, impact resistance against a large impact applied in a short time or an impact having a vertical component with respect to the rotational direction of the actuator is relatively low, and there is a problem that the holding function of the impact resistance cannot be sufficiently exhibited; further, in order to hold the actuator at the retracted position, an iron piece and a permanent magnet are required, and there is a problem that the number of components constituting the apparatus increases, which increases the cost.

Further, the above-described conventional actuator clamp device having the swing arm clamp mechanism clamps the actuator at the retracted position so that the actuator at the retracted position does not move to the data recording area of the recording medium when a relatively large impact is applied; in particular, in the case of an actuator clamp device including a lock member and a solenoid, an iron piece provided on an actuator arm, a permanent magnet provided on a housing, a plate spring for clamping the actuator, a magnet for fixing the plate spring on the lower side, a plunger for moving the plate spring up and down, and a solenoid for moving the plunger up and down constitute the actuator clamp device, and when the disk device is stopped, the actuator is moved to a retreat position, the plate spring is moved upward in accordance with the up and down movement of the plunger, the plate spring is set to a lock state, and the actuator is locked at the retreat position; however, when a very large impact is applied in the same direction as the moving direction of the plunger, the upward stress of the plate spring and the 2 nd magnetic force of the VCM yoke need to be set to values resistant to the impact in order to maintain the locked state of the plate spring, and therefore, in order to move the plunger downward against the large resultant force of the upward stress of the plate spring and the 2 nd magnetic force of the VCM yoke, the plate spring needs to be set to the unlocked state, and a large current needs to be applied to the solenoid to generate a large magnetic force, and there is a problem that: the solenoid is large-sized, and a space for arranging each component constituting the actuator holding device for locking the actuator at the retreat position is required, so that it is difficult to miniaturize the disk device; further, the following problems are solved: many parts are required to configure the actuator clamp mechanism, which causes an increase in the cost of the device.

In addition, in a disk device in which an actuator is provided so as to be rotatable about a pivot shaft and which is composed of a head arm and a coil arm disposed on opposite sides of the pivot shaft, an inertia lever, a stopper lever, and a spring constitute an inertia stopper mechanism, and when a relatively large impact is applied to the disk device during non-operation, the inertia lever is rotated to rotate the stopper lever counterclockwise regardless of the direction of a torque applied to the stopper lever, and a stopper projection of the stopper arm is engaged with a tip end portion of an inner arm of the coil arm of the actuator moved from a state in which the stopper arm is located at a retracted position to stop the actuator; the moment of inertia of the inertia lever is set larger than the moment of inertia of the stopper lever. In the actuator clamping device with the inertia stop mechanism, the dead zone of impact can be very small, and the reliability of the actuator clamping mechanism is improved, but the actuator clamping device has the following problems: in order to constitute the inertia stopper mechanism, many parts are required, and a space for disposing the parts is also required, which causes an increase in the cost of the apparatus and hinders miniaturization.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide an actuator clamp device having a very simple structure and very high impact resistance, and a disk device including the same.

In order to achieve the above object, an actuator clamp device of the present invention has the following structure: the method comprises the following steps: an actuator including a head slider having a tongue portion formed at one end of a head support arm and provided with a signal conversion element for recording and reproducing a signal on a recording medium, an actuator sub-assembly having a voice coil mounted at the other end, a pivot bearing for supporting the actuator sub-assembly, and an elastic member for applying a biasing force in a direction in which the head slider approaches the recording medium; a ramp block consisting of a ramp portion and a ramp mounting portion having a plurality of ramps and a plurality of planes in which a tab portion of the actuator slides spatially; and a voice coil motor composed of an upper yoke, a lower yoke and a magnet fixedly mounted on the upper yoke, wherein the upper yoke, the lower yoke and the magnet are arranged in opposition to both sides of the voice coil through the voice coil included in the actuator auxiliary assembly; an actuator for rotating the actuator auxiliary assembly around a rotating shaft along the radius direction of the recording medium, and rotating the actuator auxiliary assembly around a line orthogonal to the central line of the length direction of the actuator on a plane vertical to the axial center of the rotating shaft along the direction vertical to the surface of the recording medium; the slope part has a plane corresponding to the retreating position of the actuator when the recording medium stops rotating, and a 1 st step difference side surface forming a prescribed angle with the plane at one side of the plane; further, the elastic member is provided between the bearing and the actuator sub-assembly, and is a plate spring; and the bearing is a pivot bearing having a pair of pivots.

With these configurations, it is possible to realize an actuator holding device with a very simple configuration, which can independently set the actuator sub-assembly and the elastic member-plate spring, respectively, and thus can improve the rigidity of the actuator sub-assembly, and can arbitrarily set the biasing force of the elastic member against the head slider, and thus can form an actuator having very high impact resistance, an improved resonance frequency, high responsiveness, and high access speed; further, even if a large external impact is applied to the actuator at the retracted position, the tab portion of the slope portion does not come off the plane because of the perpendicular 1 st step difference side surface provided on the side of the plane that is pressed by the pressure of the elastic member for the tab portion of the actuator and comes into contact with the plane, and therefore, the head slider can be prevented from colliding with the surface of the recording medium and damaging the signal conversion element or the recording medium mounted on the head slider.

Further, the actuator holding device of the present invention has the following structure: the actuator is capable of rotating the actuator sub-assembly in a vertical direction of the recording medium around a line connecting a pair of pivot shafts contacting the pivot shaft bearings and respective contact points of the head support arms constituting the actuator sub-assembly; a 2 nd step side surface opposed to the 1 st step side surface and having a predetermined angle is formed on the other side of the plane corresponding to the retreat position of the actuator; further, a predetermined angle of the 2 nd step side surface of the slope portion with respect to a plane corresponding to the retreat position of the actuator when the rotation of the recording medium is stopped is set to be perpendicular. The shape of the magnet is such that the size of the magnet facing the voice coil in the radial direction of rotation of the head support arm when the actuator is at the retracted position when the recording medium stops rotating is larger than the size of the magnet facing the voice coil in the radial direction of rotation of the actuator when the recording and reproducing operation is performed on the surface of the recording medium; when the actuator is rotated from the retreat position of the actuator to the recording medium side when the rotation of the recording medium is stopped, a pair of the pressing and the retreat position of the actuator is providedThe pressure of the plane is F₁Let F be the vertical driving force of the voice coil motor acting on the projecting tongue portion₃When the coefficient of friction between the tongue projecting portion and the 1 st step difference side surface when the tongue projecting portion slides on the 1 st step difference side surface is μ, and the angle of the 1 st step difference side surface with respect to the plane perpendicular to the plane is α, F, which represents the vertical driving force generated by the voice coil motor acting on the tongue projecting portion₄The following relationships exist: f₄＞F₁+μ(F₁tanα+F₃)。

With these configurations, the rotation center for rotating the actuator in the direction perpendicular to the recording medium can be accurately determined with a simple configuration, so that the positioning of the signal conversion element can be controlled more accurately, and further, when the disk device starts operating, a rotational force is applied to rotate the actuator upward in the direction perpendicular to the surface of the recording medium so that the projecting portion of the actuator is separated from the plane of the receded position-slope portion having the step difference side surfaces on both sides, and the following effects can be obtained: the tab portion is easily separated from the plane, and the actuator is moved in the direction of the recording medium.

Further, the actuator holding device of the present invention has the following structure: a pair of pivots of the pivot bearing are provided at positions symmetrical with respect to a center line in a length direction of the actuator; further, a pair of pivots are provided on the pivot bearing so that each contact point, with which the pair of pivots of the pivot bearing and the actuator sub-assembly are in contact, contacts the actuator sub-assembly on a line that passes through the axial center of the rotating shaft and is perpendicular to the axial center.

With these configurations, the following effects can be obtained: the weight balance in the width direction and the length direction of the actuator is good, and the shock resistance of the actuator is improved.

Further, the actuator holding device of the present invention has the following structure: a weight having a set mass and a fixed mounting position is provided on the actuator sub-assembly such that the center of gravity of the actuator substantially coincides with the axial center of the rotating shaft; further, the position where the weight is fixedly attached to the actuator sub-assembly is a position further outside than the voice coil with respect to the rotational shaft, or the position where the weight is fixedly attached to the actuator sub-assembly is on the head slider side with respect to the rotational shaft.

With these configurations, the following effects can be obtained: unnecessary vibration of the actuator can be suppressed even when external impact or the like is applied.

Further, the actuator holding device of the present invention has the following structure: when the recording medium stops rotating, a tab portion of an actuator auxiliary assembly constituting the actuator has a pressing force for pressing a plane corresponding to the retreat position of the actuator.

With this configuration, the following effects can be obtained: when the actuator is at the retracted position, even if an external impact is applied, the tongue portion of the actuator is restored to the retracted position of the slope portion on the plane, and the actuator can be maintained at the retracted position.

Further, the actuator holding device of the present invention has the following structure: the actuator subassembly has a recess near a center portion of the contact slider.

With this configuration, the following effects can be obtained: unnecessary tilt variation in the roll or pitch direction of the head slider during recording and reproduction in the disk apparatus is absorbed by the gimbal mechanism, and the recording and reproduction operations can be performed stably.

Further, the actuator holding device of the present invention has the following structure: the slope portion is provided near the outer periphery of the recording medium, and the magnet is provided on the opposite side of the recording medium with respect to the actuator provided with the voice coil; alternatively, the slope portion is provided near the rotational center portion of the recording medium, and the magnet is provided on the recording medium side with respect to the actuator provided with the voice coil.

With these configurations, the following effects can be obtained: the VCM generates a rotational torque to the actuator and a repulsive driving torque in a direction opposite to the direction of the magnet, and moves the actuator from the retracted position substantially upward along the 1 st step difference side surface, and further moves the actuator toward the recording medium side.

Further, the actuator holding device of the present invention has the following structure: the voice coil motor rotates the actuator in a radial direction of the recording medium.

With this configuration, the following effects can be obtained: the turning operation of the actuator can be accelerated, and the actuator can have high response characteristics.

Further, the actuator holding device of the present invention has the following structure: the ramp block has a cover portion facing a surface on which the tab portion slides.

With this configuration, the following effects can be obtained: when the actuator is rotated in the vertical direction of the recording medium by a large force due to some external factor such as falling when the actuator is at the retracted position, the tab portion of the actuator does not come off the slope portion, and the actuator or other members are not damaged.

Further, the actuator holding device of the present invention has the following structure: when the coefficient of friction between the tongue projecting portion and the 1 st step difference side surface is [ mu ] when the tongue projecting portion slides on the 1 st step difference side surface, the predetermined angle [ theta ] of the 1 st step difference side surface of the slope portion with respect to the plane corresponding to the retreat position of the actuator when the rotation of the recording medium is stopped is set to 90 [ theta ] 90+ tan^-1Mu; the predetermined angle theta of the 1 st step difference side surface of the slope portion with respect to the plane corresponding to the retreat position of the actuator when the rotation of the recording medium is stopped is set to 90 DEG-theta-90 +100 deg.

With these configurations, the following effects can be obtained: the actuator holding device can be realized with a very simple structure, and even if a large external impact is applied to the actuator at the retreat position, the protrusion part of the slope part is not separated from the plane by the approximately vertical 1 st step difference side surface arranged at one side of the plane contacted by the protrusion part of the actuator pressed by the elastic component by pressure, therefore, the head slider can be prevented from colliding with the surface of the recording medium and damaging the signal conversion element or the recording medium mounted on the head slider.

Further, in order to achieve the above object, a disk device of the present invention has the following configuration: a holder which supports a recording medium and is rotatable about an axis of the medium; a head support arm including a read/write head mounted on one end of the head support arm, wherein the head support arm is coupled to the pivot bearing for rotation about an axis of the pivot bearing away from and parallel to an axis of the media; a joint between the pivot bearing and the head support arm; the contact portion between the joint portion and the head support arm defines a rotation axis of the head support arm on a plane perpendicular to a longitudinal axis of the head support arm and an axis of the pivot bearing, wherein the head support arm is connected to the pivot bearing by a plate spring portion so as to press the support arm. The head support arm is rotatable about a rotational axis of the head support arm; wherein the force in the radial direction of the head support arm and the direction perpendicular to the radial direction is applied to the head support arm, and the head support arm is moved from the retreat position to the read/write position on the recording medium. Further, the head support arm includes a tongue portion mounted on one end of the head support arm; a slope portion for holding the tongue projecting portion when the head support arm is at the retreat position; a first step surface for preventing the tongue from moving from the retreat position to the direction of the recording medium and a maintaining plane for maintaining the tongue at the retreat position are formed on the slope. Further, a predetermined angle of the 2 nd step side surface of the slope portion with respect to a maintenance plane corresponding to the retreat position of the head support arm when the rotation of the recording medium is stopped is set to be perpendicular.

With these configurations, the following effects can be obtained: the head support arm holding device can be realized with a very simple configuration, and even if a large external impact is applied to the retracted position of the head support arm, the projecting portion of the ramp portion is prevented from coming off the holding plane by the substantially vertical 2 nd step difference side surface provided on the other side of the holding plane in which the projecting portion of the head support arm is pressed by the pressing force of the elastic member, and the projecting portion is prevented from coming off the holding plane.

In addition, the disk device of the inventionThe plate spring part is arranged between the pivot bearing and the head support arm, and the structure is as follows: the elastic component is a plate spring; further, the bearing is a pivot bearing having a pair of pivots; when the recording medium stops rotating, the tab part of the head support arm has a pressing force for pressing the maintaining plane corresponding to the retreat position of the head support arm; the magnet is arranged on the opposite side of the recording medium relative to the head support arm provided with the voice coil; the ramp portion is provided near the rotational center of the recording medium, and the magnet is provided on the recording medium side with respect to the head support arm on which the voice coil is provided; the slope portion has a cover portion facing a surface on which the tab portion slides; when the coefficient of friction between the tongue portion and the 1 st step difference side surface is [ mu ] when the tongue portion slides on the 1 st step difference side surface, a predetermined angle [ theta ] of the 1 st step difference side surface of the slope portion with respect to a maintenance plane corresponding to a retreat position of the head support arm when the rotation of the recording medium is stopped is set to 90 [ theta ] 90+ tan^-1Mu; further, a prescribed angle theta of the 1 st step difference side surface of the slope portion with respect to a maintenance plane corresponding to the retreat position of the head support arm when the rotation of the recording medium is stopped is set to 90 DEG-theta-90 +100 DEG; a 2 nd step side surface opposed to the 1 st step side surface and having a predetermined angle is formed on the other side of the holding plane corresponding to the retreat position of the head support arm; further, a prescribed angle of the 2 nd step difference side surface of the slope portion with respect to a maintenance plane corresponding to the retreat position of the head support arm when the rotation of the recording medium is stopped is set to be perpendicular; when the head support arm is at the retreat position when the recording medium stops rotating, the size of the magnet opposite to the voice coil in the direction of the rotation radius of the head support arm is larger than the size of the magnet opposite to the voice coil in the direction of the rotation radius of the head support arm when the recording and reproducing operation is performed on the surface of the recording medium; when the head support arm is rotated from the retreat position of the head support arm to the recording medium side when the rotation of the head support arm is stopped, the pressing force for pressing the maintenance plane corresponding to the retreat position of the head support arm is set to F₁Setting the vertical drive of the voice coil motor to the tongue portionForce F₃When the coefficient of friction between the tongue projecting portion and the 1 st step difference side surface when the tongue projecting portion slides on the 1 st step difference side surface is μ, and the angle of the 1 st step difference side surface with respect to a plane perpendicular to the plane is α, F, which represents the vertical driving force generated by the voice coil motor acting on the tongue projecting portion₄The following relationships exist: f₄＞F₁+μ(F₁tanα+F₃)。

With these configurations, the following effects can be obtained: when the disk device is stopped, the head support arm can be clamped by a very simple structure, and the head support arm can not be separated from the retreating position by large external impact, so that the head slider can not collide with the surface of the recording medium to damage the signal conversion element or the recording medium mounted on the head slider, and the disk device with very high impact resistance, high response characteristic and high reliability of high-speed access can be realized.

Drawings

Fig. 1 is a plan view of the configuration of a main part of a disk device according to an embodiment of the present invention when an actuator is in a retracted position.

Fig. 2 is a schematic side view of the structure of an actuator of a disk device according to an embodiment of the present invention.

Fig. 3 is an exploded perspective view of the structure of an actuator of the disk device of the embodiment of the present invention.

Fig. 4 is a partially enlarged plan view of the vicinity of the ramp block when the actuator of the disk device according to the embodiment of the present invention is at the retracted position.

Fig. 5 is an enlarged partial cross-sectional view of the ramp portion, tab portion and recording medium cut along the cover portion of the ramp block in the disk device according to the embodiment of the present invention.

Fig. 6(a) to (c) are enlarged sectional views of the shape of the tab portion of the disk device according to the embodiment of the present invention.

Fig. 7 is an explanatory view of a force with which the tab portion presses the side surface of the step difference of the slope portion when an impact for rotating the actuator is received in the disk device according to the embodiment of the present invention.

Fig. 8 is a partially enlarged plan view of a voice coil and a magnet constituting a VCM in the disk apparatus according to the embodiment of the present invention.

Fig. 9(a) is a graph showing the relationship between the rotational angle position of the actuator and the rotational torque of the VCM in the disk apparatus according to the embodiment of the present invention.

Fig. 9(b) is a graph showing the relationship between the rotation angle position of the actuator of the disk apparatus according to the embodiment of the present invention and the repulsive driving torque of the VCM.

Fig. 10 is an explanatory view of the urging force of the tab portion pressing the step difference side surface of the slope portion at the start of the operation of the disk device according to the embodiment of the present invention.

Fig. 11 is a perspective view of a schematic structure of a main portion of another magnetic disk device according to the embodiment of the present invention.

Fig. 12 is a side view of another structure of an actuator included in the magnetic disk apparatus according to the embodiment of the present invention.

Fig. 13 is an exploded perspective view of the structure of a pivot bearing portion of the actuator shown in fig. 12.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(embodiment mode)

Fig. 1 to 8 are explanatory views of an actuator holding device in a disk device according to an embodiment of the present invention. Fig. 1 is a plan view of the configuration of the main part of the disk device when the actuator is at the retracted position, fig. 2 is a schematic side view of the configuration of the actuator, fig. 3 is an exploded perspective view of the configuration of the actuator, fig. 4 is an enlarged partial plan view of the vicinity of the ramp block when the actuator is at the retracted position, fig. 5 is an enlarged partial cross-sectional view of the ramp portion, the tab portion, and the recording medium cut along the cover portion of the ramp block, fig. 6 is an enlarged cross-sectional view of the shape of the tab portion, fig. 7 is an explanatory view of the force with which the tab portion presses the 1 st step difference side surface of the ramp portion when an impact is applied to rotate the actuator toward the recording medium side, and fig. 8 is an enlarged partial plan view of the voice coil and the magnet constituting the VCM viewed from the magnet.

Hereinafter, a disk device will be described by taking a disk device as an example.

In fig. 1, a recording medium 4 having a recording medium layer formed on the surface thereof is placed on a hub (rotor hub) portion 3 fixedly attached to a rotary shaft 2 of a spindle motor (not shown) rotating about a rotation center 1. On the other hand, in a signal conversion element rocker arm actuator 7 supported by a bearing 6 so as to be rotatable about a rotation axis 5, a projecting tongue portion 8 is formed at one end, a head slider 9 on which a signal conversion element, a magnetic head (not shown), is mounted is disposed on the rotation axis 5 side of the projecting tongue portion 8 via a gimbal mechanism (not shown), and a voice coil 10 is disposed at the other end, and is rotatable about the rotation axis 5 in a direction parallel to the surface of the recording medium 4. In order to contact the tongue portion 8 provided on the actuator 7 to guide the actuator 7 up and down, a slope block 15 having a slope portion 14 provided with a guide portion is mounted on a base or other housing. An upper yoke 12, on which a magnet 11 is fixedly mounted, is mounted on the chassis or other housing, so as to face the voice coil 10, above the voice coil 10, i.e., on the side opposite to the recording medium 4 with respect to the actuator 7 provided with the voice coil; further, the lower yoke 13 is attached to a chassis or other housing below the voice coil 10, facing the voice coil 10 with the voice coil 10 interposed therebetween. Further, the voice coil 10, the magnet 11 fixedly attached to the upper yoke facing the voice coil 10, and the lower yoke 13 constitute a VCM (voice coil motor). When a current is supplied to the voice coil 10 opposed to the magnet 11, the VCM operates to rotate the actuator 7 in the radial direction of the recording medium 4, and when the magnetic disk device operates, the actuator 7 rotates around the rotation axis 5 and moves on the data recording area of the rotating recording medium 4; when the magnetic disk apparatus is not in operation, the actuator 7 is rotated clockwise to rotate the actuator 7 to a predetermined position of the slope portion 14, which is the retreat position.

Next, the structure of the actuator 7 will be described with reference to fig. 2 and 3. In fig. 2 and 3, a head slider 9 on which a magnetic head (not shown) is mounted via a gimbal mechanism 22 is disposed on a head support arm 21 having a tongue portion 8 at one end and a hole portion 21a at the other end, thereby constituting a head support arm unit 23. When the magnetic head slider 9 is mounted via the gimbal mechanism 22 by providing the pit 21b in contact with the vicinity of the central portion of the magnetic head slider 9 and by bringing the pit 21b into contact with the gimbal mechanism 22 or the substantially central portion of the top surface (the surface opposite to the surface on which the magnetic head is mounted) of the magnetic head slider 9, it is possible to follow unnecessary vibrations in the roll or pitch direction of the magnetic head slider 9 with respect to the recording medium 4 during operation of the magnetic disk apparatus with good flexibility. Further, the voice coil 10 is attached to a voice coil frame 24 having a hole 24a, a weight 25 is fixedly attached to the side opposite to the hole 24a with the voice coil 10 interposed therebetween to form a voice coil portion 26, and the voice coil portion 26 is fixedly attached to the head arm unit 23 to form an actuator sub-assembly 27. Here, the head support arm unit 23 and the voice coil portion are described as different members, but are by no means limited thereto and may be 1 unit as an integrated body.

On the other hand, one end of a leaf spring part 28 which is an elastic member having a substantially annular shape in a top view and a substantially zigzag 2-step zigzag shape in a side view is fixedly attached to a pivot bearing 30 having a pair of pivot shafts 30a and 30b and a hole part 30c via a semi-annular leaf spring fixing member 29, further, the plate spring portion 28 is inserted into the hole portion 21a of the head support arm 21, the pair of pivot shafts 30a and 30b of the pivot bearing 30 are brought into contact with the top surface of the head support arm 21, the other end of the plate spring portion 28 is fixedly attached to the bottom surface of the head support arm 21, the actuator sub-assembly 27 having the head support arm 21 as a member and the pivot bearing portion 30 are elastically connected to each other via the plate spring portion 28 and the pair of pivot shafts 30a and 30b by the elastic member plate spring portion 28, the leaf spring portion 28 also functions as a contact point P between a pair of pivot shafts 30a and 30b of the pivot bearing 30 and the top surface of the head support arm 21.₁And P₂The actuator arm 31 is constituted by pressing the tongue portion 8 side of the head support arm 21 constituting the actuator auxiliary unit 27 downward as a fulcrum. Therefore, when the magnetic disk apparatus is operated, the balance ring mechanism 22 is mounted on the magnetic headThe load of the magnetic head slider 9 when the magnetic head slider 9 on the support arm unit 23 floats on the surface of the recording medium 4 is caused by the contact points P of the pair of pivots 30a and 30b of the pivot bearing 30₁And P₂The reaction force due to the deformation of the plate spring portion 28 applied to the head support arm unit 23, i.e., the compressive stress in the direction of the recording medium 4, is generated, and the magnetic head slider 9 is floated in accordance with the relationship between the pressing force in the direction of the recording medium 4 applied to the magnetic head slider and the buoyancy in the opposite direction, so that the plate spring portion 28 is deformed, and a predetermined gap is maintained between the magnetic head slider 9, i.e., the magnetic head, and the recording medium 4, thereby performing recording and reproducing in and from the magnetic disk apparatus.

Further, a hollow flanged cylindrical bearing portion 32 is constituted by a flange 32a having an outer diameter larger than the inner diameter of the hole portion 30c of the pivot bearing 30 on one end side, a screw portion 32b having an outer diameter smaller than the inner diameter of the hole portion 30c of the pivot bearing 30 on the other end side, and a cylindrical portion 32c having an outer diameter fitted into the hole portion 30c of the pivot bearing 30 between the flange 32a and the screw portion 32b, and the bearing portion 32 is made to penetrate the hole portion 30c of the pivot bearing 30, the inner side of the semi-annular shape of the leaf spring fixing member 29, the inner side of the annular shape of the leaf spring portion 28, and the hole portion 24a of the voice coil bobbin 24; on the other hand, the hollow collar 33 has an inner diameter fitted to the cylindrical portion 32c from the side opposite to the flange 32a and an outer diameter of the hole portion 24a penetrating the voice coil bobbin 24, and is provided with a semi-annular projecting portion 33a having substantially the same shape as a portion of the substantially zigzag plate spring portion 28 contacting the plate spring fixing member 29 when viewed from the side, and the collar 33 is inserted and fitted to the cylindrical portion 32c of the bearing portion 32 so that the projecting portion 33a reaches the flange 32a side of the bearing portion 32; the top surface 33b of the projection 33a is brought into contact with the substantially annular flat surface portion of the leaf spring portion 28 fixedly attached to the leaf spring fixing member 29, and the collar 33 is sandwiched and integrated by the flange 32a of the bearing portion 32 and the nut 34 together with the leaf spring fixing member 29 and the flat surface portion of the leaf spring portion 28 fixedly attached to the leaf spring fixing member 29, thereby constituting the actuator 7.

Next, the positions of the pair of pivot shafts 30a and 30b provided in the pivot bearing 30 constituting the actuator 7 will be described. The pivots 30a and 30b contact points P on the top surface of the head support arm 21, respectively₁And a contact point P₂The line (c) passes through the axial center of the rotating shaft 5 of the actuator 7 shown in fig. 1 and is perpendicular to the center line of the actuator 7 shown in fig. 1 in the longitudinal direction. Among them, it is preferable to contact the point P₁And a contact point P₂Are arranged at positions symmetrical to each other with respect to the axial center of the rotary shaft 5 of the actuator 7 so that the contact points P₁And a contact point P₂The midpoint of the connecting line (2) is substantially coincident with the axis of the rotating shaft 5. With this configuration, the actuator auxiliary unit 27 constituting the actuator 7 can be brought into contact with the contact points P around the pivot shafts 30a and 30b₁And a contact point P₂The connection line (2) is rotated in a direction perpendicular to the surface of the recording medium 4, and the magnetic head slider 9 mounted on the magnetic head support arm 21 constituting the actuator auxiliary unit 27 is urged toward the recording medium 4 by the elastic force of the plate spring portion 28.

Further, the mass (weight) of the weight 25 is set, and the weight 25 is fixedly attached to one end of the voice coil bobbin 24 constituting the voice coil portion 26 so that the position of the center of gravity of the actuator 7 and the pivot bearing 30 are brought into contact with the contact point P of the top face of the head support arm 21 constituting the actuator auxiliary assembly 27, respectively₁And P₂The midpoints of the connecting lines of (a) are substantially coincident. That is, when the actuator 7 is configured, the center of gravity of the actuator 7 is substantially aligned with the axial center of the rotating shaft 5 of the actuator 7. However, the center of gravity of the actuator support unit 27 may be approximately aligned with the axial center of the rotating shaft 5 as described above, and the degree of deviation from the center of gravity of the actuator 7 in this case is not practically problematic. Further, it is described that the weight 25 is fixedly mounted on one end of the voice coil bobbin 24, but sometimes it is necessary to be provided on the head slider 9 side of the head support arm unit 23 in accordance with the mass (weight) distribution of the respective members constituting the actuator 7.

By configuring the actuator 7 as described above, the head support arm 21 configuring the actuator 7 can be formed of a material having high rigidity, so that impact resistance against a large external impact or the like can be improved, the resonance frequency of the head support arm 21 can be increased, a vibration mode which has been problematic in the past is not generated, and stable operation is not necessary, so that the actuator 7 can be rotated and positioned at high speed, and the access speed of the magnetic disk device can be improved. Further, the elastic member, namely, the plate spring portion 28 is not formed integrally with the magnetic head support arm 21 as 1 member, but is provided as a separate member independent from the magnetic head support arm 21, so that the requirements of increasing the load on the magnetic head slider 9, improving the flexibility, and improving the rigidity of the structural body can be independently realized as the functions of different members, respectively, and the design of the actuator 7 is simplified and the degree of freedom in design can be dramatically expanded. Further, since the forming process of the plate spring portion, which is very precise as in the conventional magnetic head support arm, is not required, the magnetic head support arm can be formed more easily than in the conventional art, and the strength and the spring constant of the plate spring portion 28 can be set to predetermined desired values by setting the thickness, the material, and the like of the plate spring portion 28 alone.

As is well known, when a disk apparatus is stopped, a so-called load/unload method is employed: rotating the actuator 7 around the rotating shaft 5 to move the recording medium 4 to the outside; next, the slope portion 14 for guiding the actuator 7 and guiding the actuator to the retracted position in the unloading operation at this time will be described.

In fig. 4 and 5, the slope block 15 attached to the base or other housing has a slope portion 14 and a lid portion 42 protruding from the side surface of the slope attachment portion 41 in the horizontal direction, and is attached so that a part of the slope portion 14 overlaps with the top and bottom of the recording medium with a gap in the axial direction of the rotation center 1 of the recording medium 4. The ramp portion 14 has a top surface 43 including a 1 st inclined surface 14a, a 1 st flat surface 14b, a 2 nd inclined surface 14c, a 1 st step difference side surface 14d, a 2 nd flat surface 14e, and a 2 nd step difference side surface 14f, and the tongue portion 8 of the head support arm 21 constituting the actuator 7 guides the actuator 7 while contacting the top surface 43 of the ramp portion 14. Further, the interval between the bottom surface of the cover portion 42 and the 1 st plane 14b of the slope portion 14 is larger than the size of the tongue portion 8 of the head support arm 21 passing therethrough. However, the 2 nd slope 14c may not be provided.

The 1 st flat surface 14b and the 2 nd flat surface 14e of the slope portion 14 are on planes parallel to a plane perpendicular to the rotation axis 5, the 1 st step side surface 14d is on a plane forming an angle of (90+ α) ° with the 2 nd flat surface 14e, and the height in the axial direction of the rotation axis 5 is at least larger than the height in the axial direction of the rotation axis 5 of the tab portion 8 of the head support arm 21. The 2 nd step difference side surface 14f is located on a plane substantially perpendicular to the 2 nd plane 14e, and has a height at least higher than the 1 st plane 14 b. However, as is well known, the 2 nd step difference side surface does not need to be provided by providing a stopper that contacts the end surface of the voice coil bobbin 24 on a structural member such as a base or a case in order to prevent the actuator 7 from rotating to the side opposite to the recording area side of the recording medium 4 and separating from the slope portion 14.

When a stop command is input to the magnetic disk device, a current is supplied to the VCM while the recording medium 4 is rotated, and the actuator 7 is rotated clockwise and moved to the outside of the recording medium 4. In the vicinity of the outer peripheral portion of the recording medium 4, the tongue portion 8 of the head support arm 21 constituting the actuator 7 contacts the 1 st inclined surface 14a of the slope portion 14, and is guided to the 2 nd flat surface 14e by the 1 st inclined surface 14a, the 1 st flat surface 14b, the 2 nd inclined surface 14c, the 1 st step difference side surface 14d, and the 2 nd flat surface 14e of the slope portion 14 in this order by clockwise rotation of the actuator 7, whereby the actuator 7 stops rotating, and the 2 nd flat surface 14e becomes the retreat position of the actuator 7. The rotation of the recording medium 4 is stopped while the actuator 7 is guided on the top surface 43 of the slope portion 14 or after the actuator is guided to the retracted position.

When the tongue portion 8 of the head support arm 21 constituting the actuator 7 contacts the 2 nd plane 14e at the retreat position, the plate spring portion 28 constituting the actuator 7 generates a biasing force F for pressing the tongue portion 8 against the 2 nd plane 14e₁。

Further, the shape of the tab portion 8 of the head support arm 21 sliding on the top surface of the slope portion 14 thus configured will be described. In order to slide on the 1 st inclined surface 14a, the 1 st flat surface 14b, the 2 nd inclined surface 14c, and the 1 st step side surface 14d of the slope portion 14, the outer peripheral shape of the tongue protruding portion 8 must have no engaging portion such as a rim on the outer periphery of at least half of the circumference, and is preferably a semicircular moon shape or a cylindrical shape having a cylindrical shape of at least half of the circumference. The shape is not limited to the cylindrical shape, and may be an elliptical shape or a shape having another part having an elliptical shape, as long as it has a smoothly changing curved surface. The head support arm 21 having the tongue portion 8 is generally formed of a plate-like material, and has a substantially rectangular cross-sectional shape; however, as shown in fig. 6(a), the outer periphery of the tongue portion 8 may be machined into a semicircular moon shape by a known machining method such as press machining; as shown in fig. 6(b) and 6(c), the plate-like projecting portion 8 may be integrally molded with a material such as resin so as to have a semicircular moon shape or a cylindrical shape.

In the above description, the slope block 15 having the slope portion 14 for guiding the actuator 7 to the retracted position is provided near the outer periphery of the recording medium 4, but it is needless to say that the present invention is not limited to this, and it is also possible to provide the slope block near the rotation center 1 of the recording medium 4 by attaching the slope block to a fixed shaft in the case where a spindle motor for rotating the recording medium 4 is of a shaft-fixed type, or by attaching the slope block to a component such as a housing or a cover of the apparatus. In this case, the 1 st step difference side surface 14d of the slope portion 14 is provided on the recording area side of the recording medium 4 of the 2 nd plane 14 e.

Next, a case where the magnetic disk apparatus receives a very large external impact such as an impact due to dropping, vibration during carrying or a collision with another object when the magnetic disk apparatus is stopped will be described.

The actuator 7 rotating about the rotating shaft 5 is subjected to linear acceleration and angular acceleration due to a large external impact applied to the disk apparatus. An impact force caused by the linear acceleration acts on the center of gravity of the actuator 7, and the magnitude of the impact force depends on the weight of the actuator 7. Further, an impact force due to the angular acceleration acts as a couple on the center of the rotating shaft 5, and the magnitude of the couple generated by the impact force depends on the moment of inertia of the actuator 7. On the other hand, as described above, the position of the center of gravity of the actuator 7 is set to substantially coincide with the axial center of the rotating shaft 5 of the actuator 7, so that the impact force due to the linear acceleration acts on the axial center of the rotating shaft 5, and the actuator 7 is caused to revolve around the rotating shaft 5 and the contact points P of the pivot shafts 30a and 30b₁And a contact point P₂The force to rotate connected to it hardly acts and the actuator 7 hardly rotates. However, the wireThe axial component of the rotating shaft 5 in the impact force due to the acceleration causes the actuator sub-assembly 27, the fixing member 9, the plate spring portion 28, and the collar 33 to receive the axial force of the rotating shaft 5, and causes the actuator sub-assembly 27 to move in the axial direction of the rotating shaft 5 against the stress of the plate spring portion 28. Therefore, even if a force moving in the axial direction of the pivot shaft 5 acts, the actuator auxiliary unit 27 moves, and the tongue-protruding portion 8 of the head support arm 21 floats up from the 2 nd flat surface 14e of the ramp portion 14, and returns to the 2 nd flat surface 14e of the ramp portion 14, which is the original position before the movement, when the movement is completed and the return is made. Further, the couple of the impact force due to the angular acceleration rotates the actuator 7 about the rotation axis 5 against the force (the pressing force F) with which the tongue-protruding portion 8 of the head support arm 21 presses the 2 nd plane 14e of the slope portion 14₁) The resulting friction causes the actuator 7 to move. Therefore, when the magnetic disk apparatus is stopped, a force for moving the head slider 9 mounted on the actuator 7 in a direction from the retracted position of the actuator 7 toward the recording medium 4 or in a direction opposite thereto is generated by an impact force due to angular acceleration during the impact due to a large external impact.

Therefore, when a large external impact is applied to pivot the actuator 7 toward the recording medium 4, in order to prevent the tongue portion 8 of the head support arm 21 from moving in the direction of the recording medium 4 on the 1 st step side surface 14d formed at an angle of (90+ α) ° with respect to the 2 nd plane 14b of the slope portion 14, that is, a plane substantially perpendicular to the rotational axis 5, as shown in fig. 7, as a force acting on the 1 st step difference side surface 14d at the contact point S where the tab portion 8 contacts the 1 st step difference side surface 14d of the slope portion 14, the component force Fsin α in the direction of the 1 st step difference side surface 14d in the impact force F of the angular acceleration due to the impact applied to the tab portion 8 must be smaller than the component force Fcos α in the direction perpendicular to the 1 st step difference side surface 14d in the impact force F of the angular acceleration due to the impact applied to the tab portion 8 and the pressing force F of the tab portion 8 against the 2 nd plane 14 e.₁Of the first step difference side surface 14d, and a component force F in a direction perpendicular to the 1 st step difference side surface 14d₁sin alpha caused friction force mu (Fcos alpha + F)₁sin α) (where μ is a friction coefficient between the 1 st step difference side surface 14d and the projecting portion 8), and a pressing force F of the projecting portion 8 to the 2 nd plane 14e₁The 1 st step difference side surface 14d direction component force F₁Sum of cos α. That is, the formula (1) may be satisfied.

Fsinα≤μ(Fcosα+F₁sinα)+F₁cos alpha- (formula 1)

On the other hand, since μ > 0, F₁If > 0, sin α is not less than 0, and cos α is not less than 0, the expression is (formula 2).

μF₁sinα+F₁cos alpha > 0- (formula 2)

Thus, (formula 3) was obtained.

μFcosα＜μ(Fcosα+F₁sinα)+F₁cos alpha- (formula 3)

Therefore, if (expression 4) is satisfied, the tongue portion 8 does not move in the direction of the recording medium 4.

Fsin alpha is less than or equal to mu Fcos alpha (formula 4)

Therefore, the 1 st step difference side surface 14d is made to satisfy (equation 5) with respect to the plane perpendicular to the 2 nd plane 14 b.

α≤tan^-1Mu- (formula 5)

Therefore, the (equation 6) is satisfied with respect to the 2 nd plane 14 b.

90≤θ＝(90+α)≤90+tan^-1Mu- (formula 6)

For example, if μ ≧ 0.2, α ≦ 11 ° is set by making the 1 st step-difference side surface 14d of the slope portion 14 and the 2 nd plane 14e to form

The 1 st step side surface 14d of the slope 14 prevents the tongue portion 8 of the head support arm 21 from moving in the direction of the recording medium 4.

Further, when an impact is applied in a direction to separate the actuator 7 from the recording medium 4, since the 2 nd step difference side surface 14f of the slope portion 14 is a plane substantially perpendicular to the 2 nd plane 14e, that is, substantially perpendicular to a plane perpendicular to the axial center of the rotation shaft 5 of the actuator 7, and the lid portion 42 is formed on the slope block 15, even if a force to rotate the actuator 7 away from the recording medium 4 is applied by a large external impact, the 2 nd step difference side surface 14f and the lid portion 42 can be prevented from rotating and do not come off the retreat position — the 2 nd plane 14 e.

Next, the movement of the actuator from the retracted position, i.e., the 2 nd plane 14c, toward the recording medium 4 in the loading operation when the operation command is issued to the magnetic disk device and the operation is started will be described.

First, the magnet 11 fixedly attached to the upper yoke 12 facing the voice coil 10 constituting the VCM fixedly attached to the voice coil bobbin 24 constituting the actuator 7 will be described. As shown in fig. 8, the magnet 11 is magnetized so that the boundary between the N pole and the S pole of the magnet 11 is positioned at the position of the actuator 7 when the magnetic head (not shown) is positioned at the center of the recording area of the recording medium 4, and is opposed to the center line 71 in the rotational circumferential direction of the voice coil 10; the shape of the magnet 11 is set so that the width of the magnet 11 in the radial direction of the rotary shaft 5 when the actuator 7 is at the retracted position is larger than the width of the magnet 11 in the radial direction of the rotary shaft 5 of the magnet 11, that is, the length direction of the actuator 7 corresponding to the operation range of the voice coil 10 when the actuator 7 operates in the recording region of the recording medium 4, and the magnet 11 is fixed to the upper yoke 12.

When a current is supplied to the voice coil 10, the VCM rotates the actuator, and a magnetic force according to fleming's right-hand law acts between the voice coil 10 and the magnet 11, and the direction in which the current flows to the voice coil 10 and the magnetic force of the magnet 11 facing the voice coil 10 determine the direction of repulsion (attraction) to the rotational direction of the actuator 7 and the direction of the magnet 11. Fig. 9(a) and 9(b) show examples of the rotational torque applied to the actuator by the VCM when a constant current is applied to the voice coil 10, and the repulsive driving torque in the direction opposite to the direction of the magnet 11. Fig. 9(b) shows the repulsive driving torque when the load operation command is issued to the VCM. In fig. 9 a and 9 b, the position of the VCM in the actuator 7 when the magnetic head (not shown) is located at the center position of the recording area of the recording medium 4 is taken as the origin of the horizontal axis direction, and the direction from the position to the retracted position of the actuator 7 is taken as the rotation angle of the VCM on the positive (+) side.

When an operation command is issued to the magnetic disk device, a current is supplied to the voice coil 10, and as shown in fig. 9(a), the actuator 7 is rotated in the direction of the recording medium 4 by the rotation torque of the VCM, and as shown in fig. 9(b), the repulsive driving torque of the VCM is applied to the actuator 7, and the tongue-protruding portion 8 of the head support arm 21 is moved upward from the 2 nd plane 14e of the slope portion 14. At this time, the rotation torque of the VCM generates a force to move the actuator 7 toward the recording medium 4, and a horizontal driving force F is applied to the tongue portion 8 of the head support arm 21 constituting the actuator 7₃Pressing the 1 st step difference side surface 14d of the slope portion 14. Further, the repulsive driving torque of the VCM causes the actuator 7 to pivot about the contact points P of the pivot 30a and the pivot 30b in the direction perpendicular to the surface of the recording medium 4₁And a contact point P₂Rotates along the connecting line of the cam, and applies a vertical driving force F to the tongue portion 8 to lift the tongue portion 8 upward₄。

As shown in fig. 10 by the urging force of the tongue portion 8 pressing the 1 st step difference side surface 14d against the contact point T contacting the 1 st step difference side surface 14d of the slope portion 14, the urging force F acting on the tongue portion 8₁And horizontal driving force F of VCM₃Is a force pressing the 1 st step difference side surface 14d, and the vertical driving force F of the VCM₄Is a deviating force that deviates the tab portion 8 from the 1 st step difference side 14 d. Therefore, the pressing component f in the direction perpendicular to the 1 st stepped-difference side surface 14d out of the force pressing the 1 st stepped-difference side surface 14d can be used₁And a component f of the separating force of the tongue projecting portion 8 in the direction perpendicular to the 1 st step difference side surface 14d₂In this relation, the vertical driving force F is set so that the actuator 7 can be rotated from the retracted position to the recording medium 4 side beyond the 1 st step side surface 14d of the slope portion 14₄。

Pressing component force f in the direction perpendicular to the 1 st step difference side surface 14d₁And a deviation component force f₂Are respectively (formula)7) And (formula 8).

f₁＝F₁sinα+F₃cos alpha- (formula 7)

f₂＝F₄sin alpha (formula 8)

Therefore, in the pressing force component f₁And a deviation component f₂When the relationship (2) satisfies (equation 9),

f₁≤f₂the tongue protruding portion 8 of (formula 9) does not apply a force for pressing the 1 st step difference side surface 14 d. Therefore, the vertical driving force F of the VCM for rotating the actuator 7 from the retracted position to the recording medium 4 side beyond the 1 st step side surface 14d of the slope portion 14 is set to be larger than the vertical driving force F of the VCM₄It is sufficient to set so as to satisfy (expression 10).

F₄≥F₁- (formula 10)

In addition, in the pressing force component f₁And a deviation component f₂In the case where the relationship of (1) satisfies (equation 11),

f₁＞f₂equation (11) in order to make the actuator 7 across the 1 st step side 14d and to rotate to the recording medium 4 side, the VCM vertical driving force F₄The 1 st step difference side surface 14d direction component force f₆Greater than pressing component force f₁And a deviation component f₂Resulting frictional force f with the 1 st step difference side surface 14d₃And the pressing force F of the tab portion 8₁The 1 st step difference side surface 14d direction component force f₄Applied resistive force f₅And (4) finishing. I.e. the friction force f₃And component force f₄Represented by (formula 12) and (formula 13), respectively.

f₃＝μ(f₁-f₂)＝μ(F₁sinα+F₃cosα-F₄sin alpha) — (formula 12)

f₄＝F₁cos alpha- (formula 13)

Thus, the resistance force f₅Is (equation 14).

f₅＝f₃+f₄＝F₁cosα+μ(F₁sinα+F₃cosα-F₄sin alpha) — (formula 14)

On the other hand, vertical driving force F₄The 1 st step difference side surface 14d direction component force f₆Represented by (equation 15).

f₆＝F₄cos alpha- (formula 15)

Therefore, in order to rotate the actuator 7 from the retracted position to the recording medium 4 side beyond the 1 st step side surface 14d of the slope portion 14, the vertical driving force F of the VCM is simply set₄The 1 st step difference side surface 14d direction component force f₆And resistance force f₅The formula (16) is satisfied.

F₄cosα＞F₁cosα+μ(F₁sinα+F₃cosα-F₄sin alpha) — (formula 16)

Thus, (formula 17) was obtained.

F₄＞F₁+μ(F₁tanα+F₃-F₄tan α) — (formula 17)

Here, F₄＞0

tan. alpha. is not less than 0, and thus (formula 18) is obtained.

F₁+μ(F₁tanα+F₃)＞F₁+μ(F₁tanα+F₃-F₄tan α) — (formula 18)

Thus, the vertical driving force F of VCM₄Is (formula 19).

F₄＞F₁+μ(F₁tanα+F₃) - (formula 19)

Therefore, it is only necessary to set the vertical driving force F of VCM₄So as to satisfy (equation 19), the actuator 7 can be rotated from the retracted position toward the recording medium 4 side beyond the 1 st step side surface 14d of the slope portion 14.

As shown in fig. 9(b), the repulsive driving torque when the actuator 7 is located near the retracted position is large, and the repulsive driving torque when the actuator moves over the recording area of the recording medium 4 is very small, and does not have any adverse effect on the recording/reproducing operation of the magnetic disk apparatus.

By configuring the magnetic disk apparatus with the actuator 7, the VCM, and the ramp block 15, even if a large external impact is applied when the magnetic disk apparatus is stopped (not operated), the tongue portion 8 of the head support arm 21 provided with the head slider 9 configuring the actuator 7 does not come off the retreat position thereof — the 2 nd plane 14e of the ramp portion 14; when the magnetic disk apparatus is operated, the magnet 11 is provided on the opposite side of the actuator 7 of the voice coil 10 provided with the VCM and opposed to the voice coil 10, whereby the actuator 7 can be rotated so that the tongue portion 8 is easily separated from the 2 nd plane 14e of the slope portion 14 and the head slider 9 is opposed to the surface of the recording medium 4; a disk apparatus can be made to perform recording and reproducing operations without requiring a separate member for an actuator chucking device when the disk apparatus is stopped, without requiring the cost and space of a chucking mechanism, and can be made inexpensive and compact.

In the above description, the retracted position of the actuator 7 is described as being outside the recording medium 4, and the position of the magnet 11 at this time is set on the opposite side of the actuator 7 provided with the voice coil 10 from the recording medium 4 side, and is opposed to the voice coil 10; however, as shown in fig. 11, another VCM may be configured by providing a retreat position 103 of the actuator 7 corresponding to the slope block 15 inside the recording area of the recording medium 4, that is, near the rotation center 1 of the recording medium 4, providing another magnet 105 on the recording medium 4 side with respect to the actuator 7 of the voice map provided with the voice coil portion 62, and providing another voice coil 104 opposite to the other magnet 105.

In fig. 11, the same components as those in fig. 1 and 2 are denoted by the same reference numerals, and the actuator auxiliary unit 27 included in the actuator 7 is rotatably supported by a bearing about the rotary shaft 5 having the bearing, and can be positioned at a predetermined track position on the recording medium 4 by driving the rotary driving means, the VCM. The actuator sub-assembly 27, the bearing portion having the rotating shaft 5, and the voice coil portion 26 constitute the actuator 7. The voice coil 26 shown in fig. 11 may be used as the pivot driving means, but the pivot driving means is responsible for pivoting the head support arm 8 in the direction parallel to the surface of the recording medium 4.

The configuration of the retreat position 103 of the actuator 7 corresponding to the slope block 15 in the vicinity of the rotation center 1 of the recording medium 4 may be substantially the same as that shown in the cross-sectional view of fig. 5, and the description thereof will be omitted to avoid redundancy.

In the actuator structure of the magnetic disk device according to the embodiment of the present invention described above, as shown in fig. 3, the pair of pivot shafts 30a and 30b, which are the joint portions of the pivot bearing 30, are respectively located at the contact points P₁、P₂The top surface of the head support arm 21 is brought into contact with the upper surface, but as shown in FIG. 12, a pair of pivots 30a, 30b, which are joint portions, may be formed on one side of the head support arm 21, and contact points P may be formed on the bottom surfaces of the pivot bearings 30 and the pivot support arm₁、P₂And the upper part is contacted. Fig. 12 is a partial side view of another structure of an actuator included in a magnetic disk device according to an embodiment of the present invention, which is an example of a structure in which a pivot is formed on one side of a head support arm. In fig. 12, the same members as those in fig. 3 are assigned the same reference numerals.

In fig. 12, only the following structure is different from that of the actuator shown in fig. 3: the bearing part and the voice coil part are omitted; further, a joint constituting a pivot bearing is formed on the other end side of the head support arm 21 having the tongue portion 8 on one end portionA pair of pivot shafts 30a, 30b, and the bottom surface of the pivot bearing 30 and the pair of joint pivot shafts 30a, 30b at contact point P₁、P₂And the upper part is contacted. Other structures, operation methods, and the like are the same as those of the actuator described with reference to fig. 1, 2, and 3, and their description will be omitted to avoid redundancy.

In the above description, the shape of the pivot is not mentioned, and any shape may be used as long as it is a shape such as a cone, a polygonal pyramid, a hemisphere, or a semi-ellipsoid which makes contact with the 1 st base arm (base arm)201 or the head support arm 8 at the contact point. In addition, instead of the so-called half cone (かまぼこ) shape-a half cylinder or a half elliptic cylinder, the edge lines of a polyhedron may be used to make contact on a line. Fig. 13 shows an example of a pivot using a half cylinder.

However, it goes without saying that in the magnetic disk device according to the embodiment of the present invention, even if the actuator has a structure in which a pair of pivot shafts 30a, 30b constituting pivot bearings are formed on the other end side of the head support arm 21 having the tongue portion 8 at one end portion, and the bottom surface of the pivot bearing 30 and the pair of pivot shafts 30a, 30b constituting the pivot bearings are formed at the contact point P, the ramp portion for guiding the actuator to the retracted position during the unloading operation is not shown in the structures shown in fig. 12₁、P₂The slope portion shown in fig. 1, 4, and 5 can be applied as it is to the upper contact.

In the description of the pivot bearing 30 constituting the actuator 7 of the magnetic disk device according to the embodiment of the present invention, the pivot shafts 30a and 30b having a semi-elliptical spherical shape are shown in fig. 2 and 3, but the present embodiment is not limited thereto. The contact point P may be a hemispherical shape, a pyramid shape, a cone shape or the like₁And P₂The shape of (1) is such that the line connecting the vertices of the pivot is in the direction perpendicular to the center line in the longitudinal direction of the head support arm 21, and the contact points P can be formed at the vertices of the pivot and the top surface of the head support arm 21₁And P₂The head slider 9 is rotated in a direction perpendicular to the recording surface of the recording medium 4 as a fulcrum. In addition, the pivot bearing can be replaced by a bearing withoutThe bearing structure is a bearing structure which can rotate the magnetic head slider 9 in a direction perpendicular to the recording surface of the recording medium 4 by using a fulcrum, but by using a branch line. Specifically, the bearings are not formed by a pair of pivot shafts, but may be formed in a wedge shape on a line similar to a line connecting vertices of the pivot shafts in a direction perpendicular to a center line in the longitudinal direction of the support arm 21. The bearing may be formed in a shape capable of forming a branch line with the top surface of the support arm 21, such as a semi-cylinder or a semi-elliptic cylinder.

In the above description of the present embodiment, the description has been given taking the magnetic disk device as an example, but the present invention is by no means limited thereto, and it is needless to say that the present invention can be applied to a non-contact type disk recording and reproducing device such as a magneto-optical disk device or an optical disk device.

As described above, according to the present embodiment, it is possible to significantly expand the degree of freedom in the design of the actuator, form the head support arm constituting the actuator from a material having high rigidity, improve the impact resistance against a large external impact or the like, increase the load on the head slider included in the actuator, have high impact resistance against external vibration or impact during the operation of the magnetic disk device, improve the resonance frequency of the head support arm, rotate and position the actuator at high speed, and realize an excellent magnetic disk device having an increased access speed.

Further, when the magnetic disk apparatus is stopped (not operated), that is, when the actuator is held at the retracted position, the actuator is moved by a large external impact by receiving a component force in the axial direction of the rotation shaft of the linear acceleration and a couple of forces due to the angular acceleration at the position of the center of gravity of the actuator, but the 1 st step difference side surface or the 2 nd step difference side surface of the slope portion can prevent the movement of the tab portion of the head support arm constituting the actuator, and the tab portion can be clamped on the 2 nd plane of the retracted position of the actuator and the slope portion. Therefore, the actuator is constituted by rotating a head support arm having a head slider and a tab portion about a line passing through the axis of the rotation shaft of the actuator and perpendicular to the center line in the longitudinal direction of the actuator; a slope guide tongue portion having a 1 st step difference side surface and a 2 nd step difference side surface, which have side surfaces substantially perpendicular to a 2 nd plane, on both sides of the 2 nd plane of the slope portion, which is a retreat position of the actuator, respectively; a Voice Coil Motor (VCM) is configured by combining an actuator provided with a voice coil and a ramp, arranging a magnet fixedly mounted on an upper yoke on the side opposite to a recording medium and arranging a lower yoke on the recording medium side, thereby realizing a signal conversion element rocker arm clamping mechanism which is an actuator having very high impact resistance. When the magnetic disk apparatus starts operating, a repulsive driving torque is generated between the voice coil and the magnet constituting the VCM, a torque that causes the actuator auxiliary unit to rotate around a line passing through the axis of the rotation shaft of the actuator and perpendicular to the center line of the longitudinal direction of the actuator acts, a force that causes the tab portion at the tip end portion of the actuator auxiliary unit to move upward is generated, and a force that causes the actuator to rotate around the rotation shaft is also generated, and the actuator is moved away from the retracted position and in the direction on the surface of the recording medium.

In this actuator clamp mechanism, a single part for clamping the signal conversion element rocker arm-actuator is not required, and the cost and space of the clamp mechanism are not required, so that a disk device which is inexpensive, compact, and has very high impact resistance can be realized.

As described above, the present invention has the following actuator structure: a pivot bearing having 2 pivots and an actuator sub-assembly having a projecting tongue portion formed at one end thereof, a head slider mounted via a gimbal mechanism and a voice coil and a balance weight fixedly mounted at the other end thereof are elastically connected to each other by a leaf spring portion which is an elastic member folded in 2 stages, so that the 2 pivots of the pivot bearing contact the actuator sub-assembly, and a stress which presses the projecting tongue portion side of the actuator sub-assembly downward (the surface side of a recording medium) with a connecting line of the 2 pivots of the pivot bearing and a contact point of the top surface of the actuator sub-assembly as a fulcrum acts to constitute an actuator arm; the actuator arm is held by a flange of a hollow flanged cylindrical bearing portion and a nut. Further, the following actuator structure is provided: forming 2 pivots of the pivot bearing such that lines of the 2 pivots of the pivot bearing and contact points of the top surface of the actuator sub-assembly respectively pass through an axial center of a rotation shaft of the actuator, the contact points being located at positions symmetrical to each other with respect to the axial center of the rotation shaft of the actuator; and the weight fixedly mounted on the actuator sub-assembly is set so that the center of gravity of the actuator is located at the midpoint of the line connecting the contact points of the respective 2 pivots of the pivot bearing.

By adopting such an actuator structure, the actuator sub-assembly constituting the actuator arm and the plate spring portion serving as a biasing force of the actuator sub-assembly for applying a load to the head slider mounted thereon in the surface direction of the recording medium are formed of different members, so that the head supporting arm constituting the actuator sub-assembly can be formed of a material having high rigidity, and it is possible to improve the impact resistance against a large external impact, to improve the resonance frequency of the actuator sub-assembly, to increase the load applied to the head slider included in the actuator, and to realize a very excellent magnetic disk device having high impact resistance against an external vibration or an impact during the operation of the magnetic disk device and having a very high access speed.

Further, an actuator clamp apparatus is constituted by: a slope part, which is formed on the guide surface of the top surface of the slope part for guiding the rocker arm-actuator of the signal conversion element to the retreat position when the stop instruction is sent to the magnetic disk device, and on the two sides of the retreat position-2 nd plane of the actuator, a 1 st step difference side surface and a 2 nd step difference side surface which are provided with surfaces approximately vertical to the 2 nd plane are respectively formed; an actuator, the center of gravity of which is located at the midpoint of the connecting line of the contact points of the 2 pivots of the pivot bearing, and the midpoint is consistent with the axis of the rotating shaft of the actuator; and a Voice Coil Motor (VCM) having a magnet fixedly attached to the upper yoke disposed on the side opposite to the recording medium and a lower yoke disposed on the recording medium side, with the Voice Coil Motor (VCM) interposed between the actuators.

By adopting the structure of the actuator clamping mechanism, even if a large external impact is applied when the magnetic disk device stops, the 1 st step difference side surface and the 2 nd step difference side surface which are respectively formed on the two sides of the 2 nd plane of the retreating position-slope part of the actuator can prevent the actuator from rotating around the rotating shaft and moving the projecting part of the actuator auxiliary assembly of the actuator, the projecting part of the actuator auxiliary assembly can not be separated from the 2 nd plane, the projecting part of the actuator auxiliary assembly can be clamped on the 2 nd plane of the slope part, and the actuator composed of the actuator auxiliary assembly can be prevented from moving to the side of the recording medium, colliding with the recording medium, damaging the surface of the recording medium, or damaging the components composing the actuator. On the other hand, when the magnetic disk device starts to operate, the repulsive driving torque generated between the voice coil and the magnet in the VCM rotates the actuator auxiliary unit with a connecting line of 2 pivots of the pivot bearing and a contact point of the top surface of the actuator auxiliary unit as a fulcrum, a force pushing up the tab portion is exerted, and a force rotating the actuator around the rotating shaft is exerted to move the actuator out of the retreat position — the 2 nd plane toward the surface of the recording medium, and the loading operation is performed as described above to start the recording and reproducing operation of the magnetic disk device. Therefore, it is possible to realize a very stable actuator clamp device having high impact resistance even when the magnetic disk device is subjected to a very large external impact while the magnetic disk device is stopped. Further, a special single member for sandwiching the signal conversion element rocker arm-actuator is not required, and the cost and space for a special individual member constituting the sandwiching mechanism are not required, so that the signal conversion element rocker arm (actuator) sandwiching mechanism which is inexpensive, small-sized, and has very high impact resistance can be realized.

Further, by incorporating the actuator clamp device having such a structure in the magnetic disk device, it is possible to realize a magnetic disk device which is inexpensive, small in size, has extremely high impact resistance, and is excellent in reliability.

Claims (17)

1. A disk device has the following structure:

a holder which supports a recording medium and is rotatable about an axis of the medium;

a head support arm (21) including a read/write head (9) mounted on one end of the head support arm, wherein the head support arm is connected to a pivot bearing (30) for rotation about an axis of the pivot bearing away from and parallel to the axis of the media;

joint parts (30a, 30b) located between the pivot bearing (30) and the head support arm (21);

contact portions (P1, P2) between the engagement portions (30a, 30b) and the head support arm (21) define a head support arm rotation axis on a plane perpendicular to the longitudinal axis of the head support arm (21) and the pivot bearing axis, wherein the head support arm (21) is connected to the pivot bearing (30) by a plate spring portion (28) so as to press the support arm, and the head support arm (21) is rotatable around the head support arm rotation axis;

the head support arm is moved from a retracted position to a read/write position on the recording medium by applying a force in a radial direction of the head support arm and a force in a direction perpendicular to the radial direction to the head support arm.

2. The disk apparatus of claim 1,

the head support arm includes a tongue portion (8) attached to one end of the head support arm;

a slope portion for holding the tongue projecting portion when the head support arm is at the retreat position;

the slope portion is provided with a first step surface for preventing the tongue portion from moving from a retracted position to the direction of the recording medium, and a holding plane for holding the tongue portion at the retracted position.

3. A disk drive apparatus according to claim 1, wherein the rigidity of the structure of said head support arm (21) is higher than the rigidity of the structure of said plate spring portion (28).

4. A disk apparatus according to claim 1, wherein said engagement portion has a pair of projections arranged symmetrically with respect to a center line of said head support arm (21).

5. A disk apparatus according to claim 1, wherein the pivot axis of said head support arm intersects said pivot bearing (30).

6. A disk apparatus according to claim 2, wherein said ramp portion has a cover portion opposed to a surface on which said tab portion slides.

7. The disk apparatus of claim 2,

setting a predetermined angle theta of the 1 st step difference side surface of the slope portion with respect to the maintenance plane corresponding to the retreat position of the head support arm when the recording medium stops rotating to be set so that the predetermined angle theta is set to be smaller than the predetermined angle theta when the coefficient of friction between the projecting portion and the 1 st step difference side surface is [ mu ] when the projecting portion slides on the 1 st step difference side surface

90≤θ≤90+tan^-1μ。

8. The disk apparatus of claim 7,

the 1 st step difference side surface of the slope portion is set to the predetermined angle θ with respect to the maintenance plane corresponding to the retreat position of the head support arm when the recording medium stops rotating

90°≤θ≤90+100°。

9. The disk drive according to claim 2, wherein a 2 nd step side surface having a predetermined angle is formed on the other side of said holding plane corresponding to the retracted position of said head support arm, facing said 1 st step side surface.

10. The disc device according to claim 9, wherein said 2 nd step side surface of said slope portion is set perpendicular to said predetermined angle of said holding plane corresponding to a retracted position of said head support arm when rotation of said recording medium is stopped.

11. The disc device according to claim 1, wherein the voice coil motor comprises a voice coil and a magnet, and a size of the magnet facing the voice coil when the head support arm is at the retracted position when the recording medium stops rotating in a radial direction of rotation of the head support arm is larger than a size of the magnet facing the voice coil when the recording medium is subjected to a recording/reproducing operation on the surface of the recording medium in the radial direction of rotation of the head support arm.

12. The disk apparatus of claim 11,

when the head support arm is rotated from the retreat position of the head support arm to the recording medium side when the rotation of the recording medium is stopped, the pressing force for pressing the maintenance plane corresponding to the retreat position of the head support arm is set to F₁The vertical driving force of the voice coil motor acting on the projecting part is set to F₃Wherein when the projecting portion slides on the 1 st step difference side surface, the coefficient of friction between the projecting portion and the 1 st step difference side surface is μ, and the angle of the 1 st step difference side surface with respect to a plane perpendicular to the holding plane is α,

f representing the vertical driving force generated by the voice coil motor acting on the tongue portion₄The following relationships exist:

F₄＞F₁+μ(F₁tanα+F₃)。

13. the disc device according to claim 2, wherein said 1 st step side surface of said slope portion is set to be perpendicular to a predetermined angle of said holding plane corresponding to a retracted position of said head support arm when rotation of said recording medium is stopped.

14. The disc device according to claim 1, wherein said plate spring portion is provided between said pivot bearing and said head support arm.

15. The disc device according to claim 1, wherein the tongue portion of the head support arm has a pressing force that presses the holding plane corresponding to the retracted position of the head support arm when the recording medium stops rotating.

16. The disc device according to claim 2, wherein said ramp portion is provided in the vicinity of an outer peripheral portion of said recording medium, and the magnet is provided on a side opposite to said recording medium with respect to said head support arm on which the voice coil is provided.

17. The disc device according to claim 2, wherein said slope portion is provided near a rotational center portion of said recording medium, and a magnet is provided on a side of said recording medium with respect to said head support arm provided with a voice coil.