JP5408955B2 - Head device - Google Patents

Description

  The present invention relates to a head device that moves a head along a recording medium, and more particularly to a head device that rotates a screw shaft by the power of a motor and moves the head by the rotational force of the screw shaft.

  2. Description of the Related Art A disk device that rotates and drives various disks such as CDs and DVDs and records and reproduces information with a head or pickup that faces the disk includes a feeding device that moves the head or pickup along the recording surface of the rotating disk. Is provided.

In a pickup feeding device described in Patent Document 1 below, a pickup is supported by a guide shaft so as to be movable, and a lead screw is provided along the moving direction of the pickup. The pickup is provided with a rack portion, and this rack portion is elastically pressed against the lead screw by a spring member such as a leaf spring, and a tooth portion formed on the rack portion is slidably fitted into a feed groove of the lead screw. Yes. When the lead screw is driven by the motor, the rotational force of the lead screw acts as a linear moving force on the rack portion, and the pickup is moved along the guide shaft.
JP 2003-208765 A

  In this type of disk device, when searching for data recorded on the disk, it is necessary to rotate the lead screw at a high speed to move the pickup at a high speed and move the pickup to a data reproduction start position or the like. is there. At this time, the control unit provided in the disk device performs speed control for accelerating or decelerating the pickup and further stopping it with reference to address data read from the disk.

  However, if the address data read from the disk is missing or if an error occurs in the control operation of the control unit, the pickup cannot stop at the proper position and stops after moving to the end of the moving range. However, there may be a malfunction that the motor continues to operate as it is and the lead screw continues to rotate.

  In this case, when the pick-up moves to the end, if the tooth portion of the rack part and the lead groove of the lead screw are engaged with each other and the lead screw cannot be rotated, the motor load suddenly increases and the motor burns. It may cause malfunction such as sticking.

  On the other hand, when the pick-up moves to the end and the tooth portion of the rack part is removed from the feed groove of the lead screw and the lead screw is idle, an increase in the load on the motor can be prevented. In this case, however, when the lead screw is reversed and the pickup is moved away from the end, the tooth part once removed cannot return to the feed groove, and the pickup cannot move. May occur.

  The present invention solves the above-described conventional problems, and allows the screw shaft to idle when the head position cannot be controlled and moves to the end of the moving range and the motor continues to rotate. An object of the present invention is to provide a head device that can reliably transmit a moving force in the return direction to the head when the head is reversed.

The present invention relates to a head that performs at least one of a recording operation and a reproducing operation on a recording medium, a guide member that guides the head along the recording medium, a screw shaft that is rotationally driven by a motor, and a rotation of the screw shaft A head device provided with a power transmission member that transmits force as a moving force of the head, and an elastic support member that is provided between the head and the power transmission member and elastically pressurizes the power transmission member to the screw shaft. In
A main fitting portion that is slidably fitted into a feed groove of the screw shaft on the same surface facing the screw shaft of the power transmission member , and the main fitting portion from the inside of the feed groove is a positive portion of the screw shaft. A regulation sliding portion that is in contact with the screw shaft when deviating in the opposite one rotation direction and that is adjacent to the main fitting portion in a direction opposite to the rotation direction is provided, and the regulation sliding portion Has a surface inclined in a direction away from the screw shaft, and the power transmission member is moved by the elastic support member so that the regulating sliding portion is moved to the screw shaft when the main fitting portion is detached in the rotation direction. Is supported to approach,
After the main fitting portion is disengaged from the feed groove, the regulation sliding portion continues to slide with the screw shaft, so that when the screw shaft is subsequently reversed, the main fitting portion is moved to the feed shaft. The posture of the power transmission member is regulated so as to return to the position where it fits into the groove.

  In the head device of the present invention, when the head moves to the end of its moving range and cannot move, the main fitting portion of the power transmission member is disengaged from the feed groove of the screw shaft, and the regulating sliding portion of the power transmission member is Continue to slide with the screw shaft. Therefore, the screw shaft is not forcibly stopped, and the load on the motor can be prevented from increasing extremely.

  Further, when the main fitting portion is disengaged from the feed groove of the screw shaft, the posture of the power transmission member is moved to a position where the main fitting portion cannot return to the feed groove by continuing to slide with the screw shaft. Can be prevented, and when the screw shaft is reversed, the main fitting portion can be returned to the position where it is fitted into the feed groove with high probability. Therefore, the head can be normally moved immediately by reversing the screw shaft.

  The recording medium of the present invention can be applied not only to optical recording heads such as CDs and DVDs, but also to magnetic recording disks and magneto-optical recording disks, and recording media other than disks or recording media that can be recorded or played back. It is.

For example, in the present invention, a sliding groove different from the feed groove is formed on the screw shaft, and an auxiliary fitting portion that can be fitted to the sliding groove is provided on the regulating sliding portion. The depth, width and pitch of the sliding groove are sufficiently smaller than the depth, width and pitch of the feed groove, and the slide groove does not have the same inclination as the feed groove. ,
When the screw shaft continues to rotate after the head reaches the end of its moving range, the main fitting portion is disengaged from the feed groove in the rotational direction of the screw shaft, and the sliding groove and the The auxiliary fitting part continues to slide.

  For example, the sliding groove is provided in a region where the feed groove is not formed on the outer peripheral surface of the screw shaft.

  In the present invention, the sliding groove is a surface orthogonal to the axial center line of the screw shaft so that the auxiliary fitting portion slides again on the same locus of the sliding groove after the screw shaft makes one rotation. It can be a ring groove formed inside.

  If the sliding groove formed on the screw shaft is a ring groove, even if the screw shaft continues to rotate after the head reaches the end of movement and the main fitting part is disengaged from the screw shaft feed groove, the power transmission member Since the auxiliary fitting part of the head keeps sliding with the sliding groove, a large force is not applied to the head in the direction of the movement end, preventing the head and the stopper provided at the movement end from being damaged. It becomes easy.

Alternatively, the slide groove, said a feed groove and opposite direction to form a spiral groove, when the main fitting portion is disengaged from the feed grooves Previous Machinery rolling direction, said sliding groove said By fitting and sliding on the auxiliary fitting portion, it is possible to apply a moving force in the opposite direction to the end of the head.

  In the present invention described above, the screw shaft continues to rotate after the head reaches the end of movement, and after the main fitting portion is disengaged from the feed groove of the screw shaft, the head is formed by fitting the auxiliary fitting portion and the sliding groove. Is moved in a direction away from the moving end, and then the main fitting portion is fitted into the feed groove, the head moves toward the moving end, and this operation is repeated. When the screw shaft continues to rotate, the head repeats reciprocating motion in the vicinity of the moving end, thereby making it easier to prevent damage to the head and the stopper provided at the moving end.

  In the present invention, a sliding surface on which the outer peripheral surface of the screw shaft slides may be formed on the regulating sliding portion.

  Even if the screw shaft continues to rotate as it is after the head reaches the end of its moving range, the head device of the present invention has a main fitting portion of the power transmission member provided on the head and a feed groove of the screw shaft. The screw shaft can be idled. Therefore, it can prevent that the load of a motor increases extremely.

  In addition, the position of the power transmission member can be regulated by continuing the sliding of the regulating sliding part and the screw shaft while the screw shaft is idling. It becomes easy to return the power transmission member to a posture in which the portion fits into the feed groove. Therefore, the moving force can be applied to the head with the rotational force of the screw shaft thereafter.

  FIG. 1 is a plan view showing a head device according to a first embodiment of the present invention provided in a disk device, and FIG. 2 is an exploded perspective view showing a screw shaft, a power transmission member, and an elastic support member. 3 and 4 are partially enlarged views of the left end surface of FIG. 1 for explaining the feeding operation of the head device.

  As shown in FIG. 1, a spindle motor 2 is provided in a drive chassis of a disk device 1, a turntable (not shown) is fixed to a rotating shaft 3 of the spindle motor 2, and a center hole of a disk as a recording medium is turned. Installed on the table and clamped.

  A head device 5 is provided on the side of the spindle motor 2. A head (optical pickup) 10 provided in the head device 5 has a head base 11 formed of a light metal material such as an aluminum alloy. A reference bearing portion 11a is provided at one end of the head base 11, and the like. A support bearing portion 11b is formed at the end.

  A reference guide shaft 12 and a support guide shaft 13 are fixed to the drive chassis in parallel to each other as guide members. As shown in FIG. 3, a radial bearing 18 is held on the reference bearing portion 11 a of the head base 11, and the radial bearing 18 slides with the reference guide shaft 12 with a minimum gap. The support bearing portion 11b is formed with a slide groove that slides with the support guide shaft 13 sandwiched from above and below (a direction orthogonal to the paper surface of FIG. 1). The head base 11 moves with reference to the reference guide shaft 12, and the vertical movement is restricted by the support guide shaft 13.

  The head base 11 moves in the α1-α2 direction. The α1 direction is the outer circumferential direction of the disk, and the α2 direction is the inner circumferential direction of the disk. As shown in FIG. 1, the bracket that supports the end portion of the reference guide shaft 12 in the α1 direction functions as the outer peripheral stopper 14, and the head base 11 is positioned in the outer peripheral direction (α1 direction). The movement end position to In addition, a part of the bracket 17 that supports the end portion on the α2 side of the reference guide shaft 12 functions as the inner peripheral side stopper 15, and the head base 11 is positioned in the inner peripheral direction (α2 Direction) movement end position.

  Inside the head base 11, a light emitting element such as a semiconductor laser, an objective lens 16 that gives light emitted from the light emitting element to the recording surface of the disk, and light reception that receives reflected light reflected from the recording surface of the disk. Elements are built-in. In addition, a correction mechanism for correcting the facing posture of the objective lens 16 with respect to the disk is provided.

  A feed mechanism for moving the head 10 in the α1-α2 direction is provided on the side of the reference guide shaft 12. The feed mechanism is provided with a metal screw shaft 20. A bracket 21 is fixed to the α1 side of the drive chassis, and a bearing member 22 is held on the bracket 21. An end 20a on the α1 side of the screw shaft 20 is rotatably supported by the bearing member 22. A bearing member 23 is held on the bracket 17, and an end 20 b on the α2 side of the screw shaft 20 is rotatably supported by the bearing member 23. The screw shaft 20 is installed in parallel with the reference guide shaft 12 and is rotatably supported.

  A driven-side helical gear 25 is fixed to an end 20b of the screw shaft 20 on the α2 side. A drive shaft 26 is rotatably supported on the bracket 17, and the drive shaft 26 is rotationally driven in both forward and reverse directions by a feed motor (not shown). The drive shaft 26 is provided with a drive-side helical gear 27. The helical gear 27 meshes with the helical gear 25, and the screw shaft 20 is rotationally driven in both forward and reverse directions by the power of the feed motor. By driving the screw shaft 20 using the helical gears 25 and 27, rattling of the rotating screw shaft 20 in the thrust direction is prevented.

  The screw shaft 20 has a feed groove 30 formed in a metal shaft having a circular cross section. The feed groove 30 is formed in a clockwise spiral shape in the α1 direction. Moreover, the outer peripheral surface 20c of the screw shaft 20 in a portion where the feed groove 30 is not formed is a cylindrical surface.

  An elastic support member 40 is fixed to the reference bearing portion 11 a of the head base 11, and a power transmission member 50 is supported on the elastic support member 40.

  As shown in FIG. 2, the elastic support member 40 is formed of a leaf spring material such as stainless steel or beryllium steel. The elastic support member 40 includes a support piece 41 fixed to the head base 11 and a bent portion 42 that is bent upward integrally from the support piece 41. A pair of upward first elastic pieces 43, 43 extend to the bent portion 42, and a pair of second elastic pieces 45, downward from the upper end portions 44, 44 of the first elastic pieces 43, 43, 45 extends integrally. A mounting portion 46 is formed integrally with the lower ends of the second elastic pieces 45, 45.

  The power transmission member 50 is made of a synthetic resin material, and a fixed convex portion 51 protruding from the back surface thereof is bonded and fixed to the mounting portion 46. The elastic support member 40 is an elastically deformable portion having a wide support piece 41 and relatively large rigidity. Further, the first elastic pieces 43 and 43 and the second elastic pieces 45 and 45 are elastic deformation portions having a relatively small rigidity and a smaller width than the support piece 41. By providing the first elastic pieces 43, 43 and the second elastic pieces 45, 45, the free length of the elastic deformation portion supporting the power transmission member 50 in the bent portion 42 can be set long. .

  The power transmission member 50 is pressed against the screw shaft 20 by the elastic force of the elastic deformation portion of the support piece 41, and the first elastic pieces 43 and 43 and the second elastic pieces 45, which have a long free length and relatively low rigidity. 45 and pressed against the screw shaft 20. The load acting on the screw shaft 20 can be reduced by pressing the power transmission member 50 against the screw shaft 20 with an appropriate force by the elastic deformation portion having a long free length and relatively low rigidity. In addition, by using an elastically deforming portion having a long free length, the natural frequency of the vibration system by the power transmission member 50 and the elastic support member 40 can be lowered, and the recording operation and reproduction of the optical head can be performed during disk rotation. It is possible to prevent unnecessary resonance from occurring at a frequency that affects the operation.

  On the upper part of the power transmission member 50, a positioning convex portion 52 extending toward the elastic support member 40 is formed. The positioning convex portion 52 is inserted between the second elastic piece 45 and the second elastic piece 45 of the elastic support member 40, and the fixed convex portion 51 is fixed to the attachment portion 46.

  The power transmission member 50 is integrally formed with a pair of main fitting portions 53 and 53 protruding toward the screw shaft 20. The main fitting portions 53 and 53 have a projecting curved surface, and the top 53a has a projecting curved surface in a cross-sectional shape that extends in the vertical direction and cuts in the width direction. As shown in FIG. 2, when the vertical line extending vertically from the axial center line O of the screw shaft 20 at an angle of 90 degrees is V, the extending direction of the top portions 53 a and 53 a of the pair of main fitting portions 53 and 53 is Inclined by an angle θ0 in the clockwise direction with respect to the vertical line V. The angle θ0 substantially coincides with the inclination angle of the spiral of the feed groove 30 with respect to the plane perpendicular to the axis center line O.

  The power transmission member 50 is provided with a regulation sliding portion 54 below the main fitting portion 53. The regulating sliding portion 54 has a concave curved sliding surface 54a. The sliding surface 54 a has at least a part of a cylindrical surface whose axis is a line parallel to the axis center line O. The cylindrical surface is formed with a radius of curvature equal to or greater than the radius of curvature of the outer peripheral surface 20 c of the screw shaft 20.

Next, the feeding operation of the head device 5 according to the first embodiment will be described.
As shown in FIG. 3, in a normal feeding operation, the power transmission member 50 is pressed against the screw shaft 20 by the elastic force of the elastic support member 40, and the pair of main fitting portions 53 and 53 are pressed into the feeding groove 30. It has been. When the screw shaft 20 is rotationally driven by the feed motor, a linear moving force in the α1 direction or α2 direction is given to the power transmission member 50 by the spiral feed groove 30, and the head 10 moves along the reference guide shaft 12. It can be moved back and forth.

  The feeding operation of the head 10 when reproducing or recording data recorded on the disk is relatively slow. At this time, the limit position of the moving range in which the head base 11 moves in the α1 direction is until the optical axis of the objective lens 16 reaches the outer peripheral end of the data recording area of the disk. Is just before hitting the outer peripheral stopper 14.

  In the search operation for finding the reading start position of the data recorded on the disk, the screw shaft 20 is rotated at a relatively high speed while reading the address data recorded on the disk, and the head 10 is in the α1 direction or the α2 direction. Can be moved relatively quickly.

  At this time, if an address data acquisition error or a control abnormality of the control unit occurs, the head 10 cannot stop at the target position, but the head base 11 stops by hitting the outer peripheral stopper 14 or stops by hitting the inner peripheral stopper 15. Thereafter, the screw motor 20 may continue to rotate without stopping the feed motor.

  FIG. 4 shows a state in which the head base 11 stops by hitting the outer peripheral side stopper 14 and the screw shaft 20 continues to rotate in the β direction.

  When the screw shaft 20 continues to rotate in the β direction while the head 10 is stopped, a lifting force in the β direction acts on the main fitting portion 53 by the feed groove 30. As shown in FIG. 4, the support piece 41 and the first elastic pieces 43 and 43 of the elastic support member 40 are deformed in the γ1 direction by this force, and the second elastic piece 45 causes the upper end portions 44 and 44 to move. It is deformed in the γ2 direction as a fulcrum. As a result, the main fitting portion 53 is disengaged upward from the feed groove 30 of the screw shaft 20, and the regulation sliding portion 54 formed below the main fitting portion 53 contacts the outer peripheral surface 20 c of the screw shaft 20. Then, the power transmission member 50 is restricted so that it cannot move in the γ2 direction any more. Further, in this restricted state, the sliding surface 54a and the outer peripheral surface 20c of the screw shaft 20 continue to slide. Since the sliding surface 54a is a concave curved surface including at least a part of the cylindrical surface, and the radius of curvature of the cylindrical surface is equal to or larger than the radius of curvature of the outer peripheral surface 20c, the sliding surface 54a and the outer peripheral surface 20c slide. It is possible to prevent an excessive load from acting on both the power transmission member 50 and the screw shaft 20 when the power transmission member 50 is on.

  If the power transmission member 50 is not formed with the regulating sliding portion 54, the second provided for the purpose of increasing the free length of the elastically deforming portion when the screw shaft 20 continues to rotate in the β direction. The elastic piece 45 is greatly deformed in the γ2 direction, the power transmission member 50 rides on the upper portion of the screw shaft 20, and a portion other than the main fitting portion 53 of the power transmission member 50 contacts the outer peripheral surface 20c of the screw shaft 20. It is easy to become. In this case, even if the screw shaft 20 is reversed thereafter, the main fitting portion 53 cannot return to the state where it is fitted in the feed groove 30.

  On the other hand, as shown in FIG. 4, when the power transmission member 50 is provided with the regulation sliding portion 54, the power transmission member 50 does not move in the γ2 direction beyond the posture of FIG. Lower end surfaces 53 b and 53 b of the fitting portions 53 and 53 are in contact with the outer peripheral surface 20 c of the screw shaft 20. Therefore, when the screw shaft 20 is stopped in the state shown in FIG. 4 and then the screw shaft 20 is reversed, the lower end surfaces 53b and 53b are aligned with the feed groove 30 by the elastic force of the elastic support member 40. The power transmission member 50 returns to the normal posture shown in FIG. 3, and the main fitting portion 53 can be fitted into the feed groove 30.

  5 and 6 show a head device 5A according to a second embodiment of the present invention. FIG. 5A is a front view of the power transmission member, and FIG. 5B is a front view of the screw shaft. FIG. 6 is a perspective view showing an elastic support member and a power transmission member.

  The screw shaft 20A shown in FIG. 5B is a region in which the feed groove 30 is formed on the metal shaft, and the feed groove 30 is not formed, like the screw shaft 20 of the first embodiment. The outer peripheral surface 20c is a smooth cylindrical surface. However, the screw shaft 20A has a plurality of sliding grooves 31 formed at the end on the α1 side.

  The sliding groove 31 is a ring groove that circulates 360 degrees around the shaft center line O in a plane perpendicular to the shaft center line O, and a plurality of the sliding grooves 31 that are ring grooves are formed on the outer peripheral surface 20c. Has been. That is, the individual sliding grooves 31 are independent from each other and are infinitely continuous around the axis center line O. The depth and width dimension of the sliding groove 31 are sufficiently smaller than the depth and width dimension of the feed groove 30, and the pitch of the adjacent sliding grooves 31 is larger than the spiral pitch of the feed groove 30. Short enough.

  In the power transmission member 50A shown in FIG. 5A and FIG. 6, a pair of main fitting portions 53, 53 are formed to project from a portion facing the screw shaft 20A. The main fitting portions 53 and 53 are the same as the main fitting portions 53 and 53 of the first embodiment. The power transmission member 50A is provided with a regulation sliding portion 54A below the main fitting portions 53, 53. A plurality of auxiliary fitting portions 56 are formed to protrude from the regulation sliding portion 54A. Each of the auxiliary fitting portions 56 is formed in parallel to a perpendicular line V that is orthogonal to the axial center line O of the screw shaft 20A. Each auxiliary fitting portion 56 is fitted into the sliding groove 31, and the width and height dimensions of the auxiliary fitting portion 56 are sufficiently larger than the width and height dimensions of the main fitting portion 53. Small. As shown in FIG. 6, the auxiliary fitting portion 56 has a projecting curved shape in cross section where the top portion extends in parallel with the vertical line V and is cut by a surface crossing the top portion.

  The elastic support member 40 that supports the power transmission member 50A is the same as that used in the first embodiment.

  In the head device 5A of the second embodiment, when the screw shaft 20A continues to rotate in the β direction after the head base 11 hits the outer peripheral side stopper 14, the main fitting portion 53 is similar to FIG. It deviates from the feed groove 30 in the rotational direction of the screw shaft 20A. At this time, the auxiliary fitting portion 56 provided in the regulation sliding portion 54A is fitted in the sliding groove 31 of the screw shaft 20A, and the auxiliary fitting portion 56 slides while the screw shaft 20A is rotating. The groove 31 continues to slide.

  Since the individual sliding grooves 31 are endless tracks that circulate around the axis center line O of the screw shaft 20A, the power transmission member 50A and the head 10 are in the α1-α2 direction while the screw shaft 20A is rotating. Stops without moving to. Further, since the auxiliary fitting portion 56 and the sliding groove 31 continue to slide, the power transmission member 50A does not move more than necessary in the γ2 direction. Therefore, when the screw shaft 20A is reversed thereafter, the same normal fitting state as shown in FIG. 3 is obtained by the elastic force of the elastic support member 40 when each of the main fitting portions 53 coincides with the feed groove 30. Return.

  The sliding groove 31 of the screw shaft 20A has a very small depth and width compared to the feed groove 30, so that when each of the main fitting portions 53 coincides with the feed groove 30, an auxiliary Even if a part of the fitting portion 56 is fitted in the sliding groove 31, the fitting is released by the elastic force of the elastic support member 40, and the main fitting portion 53 is fitted normally with the feed groove 30. It can return to the meshing state.

  FIG. 7 shows a head device 5B according to the third embodiment. FIG. 7A is a front view of the power transmission member, and FIG. 7B is a front view of the screw shaft.

  The screw shaft 20B shown in FIG. 7B has a sliding groove 32 formed at the end on the α1 side. The sliding groove 32 is formed on the outer peripheral surface 20c of the screw shaft 20B. Similarly to the sliding groove 31 shown in FIG. Small enough than.

  The sliding groove 32 is a spiral groove that is reverse to the feed groove 30 and is a single spiral groove. That is, the feed groove 30 is a clockwise spiral groove toward the α1 direction, while the sliding groove 32 is a counterclockwise spiral groove toward the α1 direction.

  In the power transmission member 50B shown in FIG. 7A, a regulation sliding portion 54B is provided below the main fitting portion 53, and an auxiliary fitting portion 57 is formed integrally with the regulation sliding portion 54B. The dimensions and pitch of each auxiliary fitting portion 57 are the same as those of the auxiliary fitting portion 56 shown in FIG. However, the direction in which the top portion of the auxiliary fitting portion 56 extends is inclined in the direction opposite to the direction in which the top portion of the main fitting portion 53 extends. As shown in FIG. 7A, the main fitting portion 53 is formed to be inclined clockwise by an angle θ0 with respect to the perpendicular V, whereas the auxiliary fitting portion 57 is opposite to the perpendicular V. It is tilted clockwise by an angle θ1. This inclination angle θ1 substantially coincides with the inclination angle of the sliding groove 32 with respect to a plane perpendicular to the axis center line O.

  In the head device 5B according to the third embodiment, when the screw shaft 20B continues to rotate in the β direction in a state where the head base 11 is in contact with the outer peripheral stopper 14 and stopped, the main fitting portion is the same as in FIG. 53 deviates from the feed groove 30 in the β direction. Then, the auxiliary fitting portion 57 is fitted into the sliding groove 32 of the screw shaft 20B. Thereafter, when the screw shaft 20B rotates in the β direction, the power transmission member 50 and the head 10 are driven by the spiral locus of the sliding groove 32. Is returned in the α2 direction. When the power transmission member 50 is slightly returned in the α2 direction, the main fitting portion 53 is aligned with the feed groove 30, and the main fitting portion 53 is fitted into the feed groove 30 by the elastic force of the elastic support member 40. In the same manner as in FIG. Then, when the power transmission member 50B is sent in the α1 direction by the rotation of the screw shaft 20B in the β direction and the head base 11 hits the outer peripheral side stopper 14, the power transmission member 50B is again in the same posture as in FIG. 57 is fitted to the sliding groove 32.

  That is, while the screw shaft 20B continues to rotate in the β direction, the power transmission member 50B and the head 10 repeat reciprocating motion in the vicinity of the outer peripheral side stopper 14. Then, when the screw shaft 20B is stopped and further reversely rotated, the main fitting portion 53 is fitted into the feed groove 30 to return to a state where a normal feeding operation can be performed.

  When the screw shaft 20B continues to rotate in the β direction, the head 10 repeats the reciprocating motion in small increments, so that an excessive load can be prevented from acting on the screw shaft 20B and the feed motor. It is easy to prevent damage to the mechanism.

1 is a plan view of a disk device including a head device according to a first embodiment of the invention; An exploded perspective view showing a screw shaft, a power transmission member and an elastic support member; The left end view of FIG. 1 showing a normal feeding operation in which the screw shaft and the main fitting portion are engaged with each other, 1 is a left end view of FIG. 1 showing the idling operation when the screw shaft is rotating even when the head reaches the moving end; The head apparatus of the 2nd Embodiment of this invention is shown, (A) is a front view of a power transmission member, (B) is a front view of a screw shaft, The perspective view which shows the power transmission member and elastic support member of 2nd Embodiment, The head apparatus of the 3rd Embodiment of this invention is shown, (A) is a front view of a power transmission member, (B) is a front view of a screw shaft,

Explanation of symbols

1 Disc device 5, 5A, 5B Head device 10 Head 11 Head base 12 Reference guide shaft (guide member)
13 Support guide shaft (guide member)
14 Outer peripheral side stopper 20, 20A, 20B Screw shaft 20c Outer peripheral surface 30 Feed groove 31, 32 Sliding groove 40 Elastic support member 50 Power transmission member 53 Main fitting portion 54, 54A, 54B Regulating sliding portion 54a Sliding surface 56 57 Auxiliary fitting part

Claims (6)

A head that performs at least one of a recording operation and a reproducing operation on a recording medium, a guide member that guides the head along the recording medium, a screw shaft that is rotationally driven by a motor, and a rotational force of the screw shaft. In a head device provided with a power transmission member that transmits as a moving force of the motor, and an elastic support member that is provided between the head and the power transmission member and elastically presses the power transmission member against the screw shaft.
A main fitting portion that is slidably fitted into a feed groove of the screw shaft on the same surface facing the screw shaft of the power transmission member , and the main fitting portion from the inside of the feed groove is a positive portion of the screw shaft. A regulation sliding portion that is in contact with the screw shaft when deviating in the opposite one rotation direction and that is adjacent to the main fitting portion in a direction opposite to the rotation direction is provided, and the regulation sliding portion Has a surface inclined in a direction away from the screw shaft, and the power transmission member is moved by the elastic support member so that the regulating sliding portion is moved to the screw shaft when the main fitting portion is detached in the rotation direction. Is supported to approach,
After the main fitting portion is disengaged from the feed groove, the regulation sliding portion continues to slide with the screw shaft, so that when the screw shaft is subsequently reversed, the main fitting portion is moved to the feed shaft. The head device is characterized in that the posture of the power transmission member is regulated so as to be able to return to a position where it fits into the groove. A sliding groove different from the feed groove is formed on the screw shaft, and an auxiliary fitting portion that can be fitted to the sliding groove is provided on the regulating sliding portion. The depth, width dimension, and pitch are sufficiently smaller than the depth, width dimension, and pitch of the feed groove, and the sliding groove does not have the same inclination as the feed groove,
When the screw shaft continues to rotate after the head reaches the end of its moving range, the main fitting portion is disengaged from the feed groove in the rotational direction of the screw shaft, and the sliding groove and the The head device according to claim 1, wherein the auxiliary fitting portion continues to slide.   The head device according to claim 2, wherein the sliding groove is provided in a region where the feed groove is not formed on an outer peripheral surface of the screw shaft.   The sliding groove is formed in a plane orthogonal to the axial center line of the screw shaft so that the auxiliary fitting portion slides again on the same locus of the sliding groove after one rotation of the screw shaft. 4. The head device according to claim 2, wherein the head device is a ring groove. The sliding groove, said a feed groove and opposite direction to form a spiral groove, when the main fitting portion is disengaged from the feed grooves Previous Machinery rolling direction, wherein the slide groove is fitted auxiliary 4. The head device according to claim 2, wherein a moving force in a direction opposite to the direction toward the end is applied to the head by being fitted and slid into the joint.   The head device according to claim 1, wherein a sliding surface on which an outer peripheral surface of the screw shaft slides is formed on the regulating sliding portion.

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