JP2003036615A - Optical disk device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical disk device wherein there is no problem of disengagement even when a pickup is moved against gravity, and the pickup is stably moved. SOLUTION: This device is constructed in such a manner that the winding direction of the groove of a lead screw for moving a pickup upward against gravity is hardly disengaged between the projection of a guide arm and the groove of the lead screw.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical disk device, and more particularly to a pickup feed mechanism for the optical disk device.

[0002]

2. Description of the Related Art In an optical disk device, a disk-shaped recording medium (hereinafter referred to as a disk) is placed on a spindle motor attached to a unit mechanism, and the disk is rotated.
The pickup 4 is moved in the radial direction of the disc by the pickup feeding mechanism, and the laser light emitted from the objective lens provided in the pickup 4 reproduces the data on the disc or records the data on the disc. Japanese Patent Laid-Open No. 2000-
As disclosed in Japanese Patent No. 339883 and Japanese Patent Laid-Open No. 11-353823, a lead screw having a spiral groove on its surface is mainly used. Power is transmitted from the motor to the lead screw by a gear train.

FIG. 7 is an exploded perspective view showing a pickup feeding mechanism of a conventional optical disk device, and shows details of a lead screw and a guide arm which constitute the feeding mechanism. In recent years, as shown in FIG. 7, there is a lead screw 1 directly connected to the motor 5 to transmit power by using a stepping motor 5. The spiral groove 1a of the lead screw 1 is processed by cutting or rolling.
The winding direction of a is generally the right direction (clockwise direction) in the processing process. The feeding mechanism includes a member 2 (hereinafter referred to as a guide arm) including a lead screw 1 and a protrusion 2a that engages with the groove 1a of the lead screw 1.
And the projection 2a of the guide arm 2 and the elastic body 3
Is pressed and engaged in the groove 1a of the lead screw 1 in the radial direction. When the lead screw 1 rotates in the direction of the arrow (counterclockwise) in the drawing, the protrusion 2a of the guide arm 2 is moved along the groove 1a of the lead screw 1 and the pickup moves.

The optical disc device is a compact disc (CD) or a digital versatile disc (DV).
It is installed in the playback device (player) of D) or a personal computer, and is used in a horizontal posture or a lower left or lower right vertical posture. The horizontal posture is the posture in which the disc rotates in the plane parallel to the ground, and the vertical posture is the posture in which the disc rotates in the plane perpendicular to the ground and the disc is inserted horizontally. When the left side of the device is down, it is called lower left, and when the right side is down, it is called lower right vertical position. Generally, in any of the above postures, the moving direction of the pickup is substantially horizontal.

[0005]

However, in recent years, a personal computer in which a disc insertion / removal port is arranged above has appeared on the market. In order to deal with this, the attitude of the optical disk device must be such that the disk insertion / ejection port faces upward (hereinafter, this attitude is referred to as the toaster attitude). In this case, since the pickup reads the signal of the disc, it moves up and down (it may move diagonally), and its own weight is always applied downward.

FIG. 8 is a schematic view showing the action of the force applied from the lead screw to the projection of the guide arm in the conventional pickup feed mechanism shown in FIG. In the figure,
When the own weight of the pickup is applied downward, the own weight of the pickup becomes a load when the pickup moves upward against gravity. When the pickup moves upward, as shown in FIG. 8, the protrusion 2a of the guide arm 2 receives the circumferential force Ft from the lead screw 1 from the rotation shaft 2b side of the guide arm 2. This force Ft is divided into a force F ₁ acting along the protrusion 2a and a force F ₂ acting perpendicularly to the force F ₁ . The force F ₂ acts as a force for moving the pickup, and the force F ₁ acts in a direction in which the protrusion 2 a of the guide arm 2 is separated from the rotating shaft 2 b indicated by the arrow B. Therefore, when the pickup moves, a force that tilts away from the lead screw 1 is applied to the engaging portion of the guide arm 2,
The protrusion 2a of the guide arm 2 is the groove 1 of the lead screw 1.
In some cases, the signal may be deviated from “a”, which may cause a problem that the signal of the disc cannot be read stably.

This will be described with reference to a simple model shown in FIG. FIG. 9 is a schematic view of the lead screw and the guide arm for explaining the force acting on the protrusion of the guide arm in the conventional pickup feeding mechanism shown in FIG. In the figure, since the lead screw 1 is rotated in the direction of arrow K (counterclockwise direction), the projection 2a of the guide arm 2 is pushed up to the projecting shape of the lead screw 1 and the guide arm 2 moves away from the lead screw 1. The force to lean is added.

In particular, it is considered that this problem is remarkable in a pickup compatible with recording such as a DVD-RAM, because the structure is complicated and the weight of the pickup is increased. Further, it may be transported or stored for a long time in a high temperature and high humidity environment by a ship or the like, but during that time, some kind of impact is applied and the projection 2a of the guide arm 2 comes off the groove 1a of the lead screw 1. It is conceivable that the lead screw is left on the outer periphery of the lead screw. Then, the guide arm 2 creeps in the direction away from the lead screw 1, and the above-mentioned problem easily occurs.

Further, when the load of the elastic member 3 pressing the projection 2a of the guide arm 2 against the groove 1a of the lead screw 1 in the radial direction is increased, the projection 2a of the guide arm 2 does not come off, but the lead is removed. The rotation resistance of the screw 1 increases and the motor 5 cannot rotate. If the torque of the motor 5 is increased in order to prevent this, the force that the guide arm 2 bends in the direction of escape from the groove 1a of the lead screw 1 is greatly exerted, and the guide arm 2 returns to its original state, leaving no room. .

It is an object of the present invention to provide an optical disk device which does not have a problem of disengagement even in a toaster posture and can perform stable movement of a pickup.

[0011]

In order to achieve the object of the present invention, in the first aspect of the present invention, an optical disk device uses a pickup for optically reading a signal from a disk-shaped recording medium on a track of the disk-shaped recording medium. On the other hand, in order to move the screw in a substantially orthogonal direction, a screw having a groove formed in a spiral shape, a protrusion that is attached to the pickup and that engages with the groove of the screw, and an elasticity that presses the protrusion into the groove of the screw. A guide member having a body, and when the screw is rotated to move the guide member along the screw, a winding direction of the groove of the screw is applied so that a force pressed by the groove acts on the protrusion. Determine.

In the second aspect of the invention, the optical disk device comprises a feed operation mechanism for moving a pickup that optically reads a signal from the disk-shaped recording medium in a direction substantially orthogonal to the track of the disk-shaped recording medium. In the optical disk device, the feed operation mechanism has a screw having a spiral groove on the surface thereof, a protrusion attached to the pickup and engaged with the groove of the screw, and the protrusion is pressed in the radial direction of the screw. A guide member having an elastic body is provided, and the winding direction of the groove of the screw when the pickup is moved upward is set so that the projection of the guide member and the groove of the lead screw are not easily disengaged. To do.

In the second aspect of the invention, the insertion and removal ports of the disk-shaped recording medium are oriented upward or downward. Further, the guide member attached to the pickup is provided with a shaft at a position that does not coincide with an engagement point of the protrusion and the groove of the screw and a position to which a biasing force of the elastic body is applied, and the engagement portion is It is rotatable based on the shaft.

According to a third aspect of the invention, an optical disk device comprises a pickup for optically reading a signal from a disc-shaped recording medium and a feed mechanism for moving the pickup in a substantially radial direction of the disc-shaped recording medium. An optical disk device in which a load applied to the feeding mechanism varies depending on a direction, the optical disc device includes a lead screw having a groove, and a protrusion holding member for holding a protrusion engaging with the groove of the lead screw, and a central axis of the lead screw. And a radial direction connecting the groove and the engagement point of the protrusion is an r-axis, a movement direction parallel to the central axis passing through the engagement point and having a large load applied to the feed mechanism is an s-axis, When considering a coordinate system that is orthogonal to the r-axis and the s-axis and has the t-axis that constitutes the right-handed system, the direction from the lead screw toward the protrusion at the engagement point is considered. When the normal line of the contact surface is an angle with the s axis when projected on the s-t plane and β is positive and the direction in which the s axis is rotated clockwise is positive, the protrusion holding member is parallel to the lead screw. Is connected to the frame of the pickup via a rotary shaft, and the rotary shaft has r-axis coordinate values and β
Is the position where the product of is positive.

According to a fourth aspect of the invention, the optical disk device comprises a pickup for optically reading a signal from the disc-shaped recording medium, and a feed mechanism for moving the pickup in a substantially radial direction of the disc-shaped recording medium. An optical disk device in which a load applied to the feeding mechanism varies depending on a direction, the optical disc device includes a lead screw having a groove, and a protrusion holding member for holding a protrusion engaging with the groove of the lead screw, and a central axis of the lead screw. And a radial direction connecting the groove and the engagement point of the protrusion is an r-axis, a movement direction parallel to the central axis passing through the engagement point and having a large load applied to the feed mechanism is an s-axis, Considering a coordinate system that is orthogonal to the r-axis and the s-axis and has a t-axis that constitutes the right-handed system, the protrusion holding member has a rotation axis that is orthogonal to the lead screw. Coupled to the pick-up frame and the pivot shaft is in the position a product of r-axis coordinate values and the s-axis coordinate value is positive.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings using some examples. In the present invention, the winding direction of the groove 1a of the lead screw 1 in which the pickup is moved upward against gravity is configured such that the protrusion 2a of the guide arm 2 and the groove 1a of the lead screw 1 are less likely to be disengaged. Accordingly, the present invention provides an optical disk device that enables stable movement of the pickup even in a toaster posture.

First, the conditions of the elements necessary to realize this pickup feed mechanism will be described. At first,
10 shows the case where the positional relationship between the lead screw, the protrusion of the guide arm, and the rotation axis of the guide arm is the same as that in FIG.
~ It demonstrates using FIG.

FIG. 10 is a model diagram in which the contact portion between the lead screw and the projection of the guide arm is expanded in the axial direction, and FIG. 11 is the circumferential development of the contact portion between the lead screw and the projection of the guide arm in FIG. FIG. 12 is a model diagram in the case of doing so, and FIG. 12 is a model diagram in the case where the contact portion between the lead screw and the protrusion of the guide arm in FIG. Ignore friction now. If the force perpendicular to the contact surface is F, the force and moment acting on the rotation shaft 2b of the guide arm 2 from the protrusion 2a will be obtained. Axial force Fs, radial force Fr, and circumferential force of the contact portion (see FIG. 10).
Then, the force Ft acting in the direction of the back surface in the direction perpendicular to the paper surface is expressed by the following expressions (1) to (3). Fs = F × cos α × cos β ………… (1) Fr = F × sin α × cos β ………… (2) Ft = F × cos α × sin β ………… (3) At this time, the guide arm The axial moment Ms acting on the two rotation shafts 2b is e in the r-axis direction from the engagement point to the two rotation shafts 2b of the guide arm, and h in the t-axis direction.
Then (see FIG. 12), it is represented by Expression (4). Ms = Fr × h−Ft × e = F × (h × sin α × cos β−e × cos α × sin β) (4) To prevent the protrusion 2a of the guide arm from coming off the groove 1a, the moment Ms is made as small as possible. Should be

Next, the conditions under which even a slight effect of making the protrusion 2a difficult to come off from the groove 1a will be examined. When the moving directions are opposite, the contact surface between the groove 1a and the protrusion 2a is the opposite surface of the groove 1a, and the signs of F and sin α are both reversed. In this case, the first term on the right side of equation (4) does not change, but the second term is F
Only the sign changes, so the sign is reversed. That is, the influence of the second term whose sign changes may be investigated. Similar to the above, force F
Considering the case where is positive, Equation (5) should be established in order to reduce Ms. e × sin β> 0 ………… (5) In addition to the above, the effect of friction is added when moving, but the above relationship may be considered as the basis.

Next, the case where the lead screw and the rotating shaft 2b of the guide arm have a relationship as shown in FIG. 13 will be described. FIG. 13 is a perspective view of a lead screw and a guide arm according to the present invention. As shown in the figure, the rotation axis 2b of the guide arm 2 extends from the protrusion 2a engaged with the groove 1a of the lead screw 1 along the axis of the lead screw 1, It extends at right angles. That is, the rotating shaft 2b extends parallel to the r-axis direction from a point extending from the position of the protrusion 2a in the s-axis direction. Now, it is assumed that the rotating shaft 2b is in the positive direction of the s axis from the engagement point. In this case, the moment Mt ′ acting on the rotating shaft 2b is expressed by the equation (6). Mt ′ = e × Fs = e × F × cos α × cos β (6) In this case, it is difficult to disengage when Mt ′> 0. Since α and β are 90 ° or less and the force F is positive, e may be positive. Also in this case, the desired condition can be easily determined by converting the coordinate direction according to the moving direction.

An embodiment of an optical disk device according to the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of an optical disc device according to the present invention.
FIG. 2 is a plan view of FIG. In FIGS. 1 and 2, 1 is a lead screw, 1 a is a groove spirally arranged on the surface of the lead screw 1, 2 is a guide arm, 2 a is a protrusion integrally formed with the guide arm 2, and 2 b is The rotation axis of the guide arm 2, 3 is a spring body, 4 is a pickup,
Reference numeral 5 is a motor directly connected to the lead screw 1, 6 is a main guide for guiding the movement of the pickup 4, 7 is a sub guide, and 8 is a chassis.

The guide arm 2 is fixed to the pickup 4 with a screw, and the projection 2a of the guide arm 2 is pressed in the groove 1a of the lead screw 1 in the radial direction by the spring 3 incorporated therein. As the lead screw 1 rotates, the projection 2a of the guide arm 2 moves along the groove 1a of the lead screw 1, and the pickup 4 is guided by the main guide 6 and the sub guide 7 arranged on the chassis 8 and the arrow L1, Move in the L2 direction (see FIG. 2).

Next, the lead screw 1 and the guide arm 2 will be described with reference to FIG. FIG. 3 is an exploded perspective view showing an embodiment of the lead screw and the guide arm of the feeding mechanism according to the present invention. In the figure, the groove 1a of the lead screw 1 is spirally wound leftward (counterclockwise) on the surface, and the advance angle (angle β shown in FIG. 11) of the groove 1a is about 20 °. Further, the groove 1a has an opening angle of 30 to 60, similar to a screw. In order to move the pickup 4 upward, the lead screw 1 rotates clockwise as viewed from the motor 5, that is, in the clockwise direction (direction of arrow M in the figure). The protrusion 2a formed integrally with the guide arm 2 is formed obliquely according to the advance angle β of the groove 1a so as to engage with the groove 1a of the lead screw 1. In FIG. 3, when the protrusion 2a of the guide arm is properly engaged with the groove 1a of the lead screw 1, the groove 1a and the protrusion 2
The relationship between a and the rotating shaft 2b is as shown in FIG. That is, the rotating shaft 2b is arranged below the position where the urging force of the elastic body 3 is applied, that is, below the shaft of the lead screw 1, and at a position away from the engaging portion between the groove 1a and the protrusion 2a. It is arranged in parallel to the direction orthogonal to the screw 1 and is connected to the main body of the guide arm 2 via a hinge serving as a rotating shaft 2b. The hinge portion has a small thickness in order to keep the urging force of the elastic body 3 constant, and is not affected by the elastic force of the hinge portion as much as possible. Further, the guide arm 2 has a shape in which the rib body 3 can be removed even after being assembled in the optical disk device, and the rib body 3 can be incorporated from above in order to make the guide arm 2 simple and inexpensive. . The protrusion 2a is pressed into the groove 1a by the elastic body 3. Thus, when the groove 1a is provided in the counterclockwise direction on the surface of the lead screw 1, the protrusion 2a and the rotating shaft 2b are
Are arranged in this relationship, the protrusion 2a is formed into the groove 1a.
Can be prevented from coming off.

Next, the action of the force received by the lead screw 1 on the projection 2a of the guide arm 2 of this embodiment will be described with reference to FIG. FIG. 4 is a schematic diagram showing the action of the force applied from the lead screw to the protrusion of the guide arm in the pickup feed mechanism shown in FIG. In this embodiment, as shown in FIG. 4, the protrusion 2a of the guide arm 2 receives the force Ft from the lead screw 1 and the rotation shaft 2 of the guide arm 2.
Receive in the direction toward the b side. The force F ₁ acts on the protrusion 2 a of the guide arm 2 in the direction toward the rotation shaft 2 b indicated by the arrow A. Therefore, when the pickup moves, a force that tilts toward the lead screw 1 is applied to the engaging portion of the guide arm 2.

5 and 6 are schematic views of the lead screw and the guide arm for explaining the force acting on the protrusion of the guide arm in the feed mechanism of the pickup shown in FIG.

In FIG. 5, the lead screw 1 is shown by forming a protruding shape in a circle, and the groove 1 is provided between the protruding shapes.
a. The guide arm 2 is represented by an L-shaped beam and has a protrusion 2a.
Is shown by projecting an L-shaped beam. In this embodiment, when the pickup 4 is moved upward, the lead screw 1 rotates in the direction of arrow N, and the state shown in FIG.
It becomes the state of. As is clear from FIG. 6, when the lead screw 1 is rotated in the direction of the arrow N (clockwise direction), the projecting shape of the lead screw 1 pushes down the projection 2a of the guide arm 2, so that the guide arm 2 is A force is added to lean toward. When the rotational force of the lead screw 1 transmitted from the motor 5 or the load when the pickup 4 is moving is large, this state becomes prominent. Therefore, even when the pickup moves upward against gravity, there is no problem of disengagement, and stable movement of the pickup can be performed. In the present embodiment, the guide arm 2 is shaped such that the rotary shaft 2b is located below the position where the urging force of the elastic body 3 is applied and away from the engaging portion. It is also possible that the winding direction of 1a is reversed and the shape of the guide arm 2 is such that the rotating shaft 2b is arranged above the position where the biasing force of the spring 3 is applied. In addition, when the protrusion 2a of the guide arm 2 is engaged with the groove 1a of the lead screw 1 and the rotary shaft 2b is arranged perpendicular to the lead screw 1 from the point of extension along the lead screw 1, 2a from the force and moment acting on the rotating shaft 2b of the guide arm 2
Mt '> 0, which is a condition in which a does not easily come off, is obtained (provided that α and β are 90 ° or less and e is positive). Thus, even in this case, the engagement is unlikely to be disengaged.

As described above, in the present invention, it is possible to derive the conditions based on the conditions in which the protrusion 2a is less likely to come off the groove 1a with reference to the above-described embodiment. Therefore, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the present invention.

As described above, according to the present invention, the problem of disengagement can be solved by changing the winding direction of the groove of the lead screw and the position of the guide arm without changing the component structure and increasing the number of components. It is possible to move the pickup stably. Therefore, the pickup feeding mechanism can be manufactured at low cost and high reliability can be achieved.

[0029]

As described above, according to the present invention, a highly reliable pickup feed mechanism which solves the problem of disengagement and enables stable movement of the pickup is provided at a low cost. be able to.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of an optical disk device according to the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is an exploded perspective view showing an embodiment of the lead screw and the guide arm of the feeding mechanism according to the present invention.

FIG. 4 is a schematic diagram showing an action of a force received from a lead screw to a protrusion of a guide arm in the pickup feeding mechanism shown in FIG.

5 is a schematic diagram of a lead screw and a guide arm for explaining a force that acts on a protrusion of the guide arm in the feed mechanism of the pickup shown in FIG.

6 is a schematic view of a lead screw and a guide arm for explaining a force acting on a protrusion of the guide arm in the feed mechanism of the pickup shown in FIG.

FIG. 7 is an exploded perspective view showing a pickup feeding mechanism of a conventional optical disc device.

FIG. 8 is a schematic diagram showing an action of force received from a lead screw to a protrusion of a guide arm in the conventional pickup feed mechanism shown in FIG.

9 is a schematic view of a lead screw and a guide arm for explaining a force acting on a protrusion of the guide arm in the conventional pickup feed mechanism shown in FIG.

FIG. 10 is a model diagram when the contact portion between the lead screw and the protrusion of the guide arm is expanded in the axial direction.

11 is a model diagram of a case where the contact portion between the lead screw and the protrusion of the guide arm in FIG. 10 is expanded in the circumferential direction.

FIG. 12 is a model diagram when the contact portion between the lead screw and the protrusion of the guide arm in FIG. 10 is expanded in the radial direction.

FIG. 13 is a perspective view of a lead screw and a guide arm according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Lead screw, 1a ... Spiral groove, 2 ... Guide arm, 2a ... Protrusion of guide arm 2, 2b ... Rotation axis of guide arm 2, 3 ... Elongation body, 4 ... Pickup, 5 ...
Motor, 6 ... Main guide, 7 ... Sub guide, 8 ... Chassis.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Tomoki Hirata             Stock Market, Toranomon 1-26-5, Minato-ku, Tokyo             Hitachi Hitachi LG Data Storage (72) Inventor Yoshihide Tabuchi             292 Yoshida-cho, Totsuka-ku, Yokohama-shi, Kanagawa             Ceremony company Hitachi Image Information System F term (reference) 5D068 AA02 BB01 CC03 EE17 GG15                 5D117 AA02 BB06 JJ10

Claims (6)

[Claims] 1. A screw having a spiral groove for moving a pickup that optically reads a signal from a disk-shaped recording medium in a direction substantially perpendicular to a track of the disk-shaped recording medium, and Attached to the pickup, comprising a protrusion that engages with the groove of the screw and a guide member having an elastic body that presses the protrusion into the groove of the screw, the screw is rotated to move the guide member along the screw. The optical disk device, wherein a winding direction of the groove of the screw is determined so that a force pressed by the groove acts on the protrusion when the screw is moved. 2. An optical disk apparatus comprising a feed operation mechanism for moving a pickup for optically reading a signal from a disk-shaped recording medium in a direction substantially orthogonal to a track of the disk-shaped recording medium, wherein The operating mechanism includes a screw having spiral grooves on the surface, and a guide member that is attached to the pickup and that has a protrusion that engages with the groove of the screw and an elastic body that presses the protrusion in the radial direction of the screw. An optical disk device, comprising: a winding direction of a groove of the screw when the pickup is moved upward so that a protrusion of the guide member and a groove of the lead screw are not easily disengaged from each other. . 3. The optical disk device according to claim 2,
An optical disc apparatus, wherein the disc-shaped recording medium is inserted or ejected in a posture facing upward or downward. 4. The optical disk device according to claim 2,
The guide member attached to the pickup is provided with a shaft at a position that does not coincide with an engaging point of the protrusion and the groove of the screw and a position where a biasing force of the elastic body is applied, and the engaging portion is the shaft. An optical disk device, which is rotatable based on the following. 5. A load comprising a pickup for optically reading a signal from a disk-shaped recording medium and a feed mechanism for moving the pickup in a substantially radial direction of the disk-shaped recording medium, and a load applied to the feed mechanism depending on a moving direction. Which are different optical disk devices, having a lead screw having a groove,
A protrusion holding member that holds a protrusion that engages with the groove of the lead screw, and a radial direction that connects the central axis of the lead screw and the engagement point of the groove and the protrusion is an r-axis, and the engagement point is A coordinate system having a movement direction parallel to the central axis and having a large load applied to the feed mechanism as an s axis, orthogonal to the r axis and the s axis, and having an axis forming a right-handed system as a t axis, When considered, the normal line of the contact surface from the lead screw toward the protrusion at the engagement point,
When the angle formed with the s-axis when projected on the s-t plane is β and the direction in which the s-axis is rotated clockwise is positive, the protrusion holding member is provided with a rotating shaft parallel to the lead screw. An optical disk device, wherein the optical disc device is connected to a frame of the pickup, and the rotation axis is at a position where the product of the r-axis coordinate value and β is positive. 6. A load comprising a pickup for optically reading a signal from a disc-shaped recording medium and a feed mechanism for moving the pickup in a substantially radial direction of the disc-shaped recording medium, and a load applied to the feed mechanism depending on a moving direction. Which are different optical disk devices, having a lead screw having a groove,
A protrusion holding member that holds a protrusion that engages with the groove of the lead screw, and a radial direction that connects the central axis of the lead screw and the engagement point of the groove and the protrusion is an r-axis, and the engagement point is A coordinate system having a movement direction parallel to the central axis and having a large load applied to the feed mechanism as an s axis, orthogonal to the r axis and the s axis, and having an axis forming a right-handed system as a t axis, In consideration of the above, the protrusion holding member is connected to the frame of the pickup via a rotation shaft that is orthogonal to the lead screw, and the rotation shaft has a positive product of the r-axis coordinate value and the s-axis coordinate value. An optical disk device characterized in that