JP2006012228A - Magnetic head actuator assembly - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To stabilize characteristics by suppressing play in a rotating portion for converting rotational movement to linear movement. <P>SOLUTION: A carriage (22A) is supported vertically movably to a head lift body (52) by a single arm (73). Thus a gap between a carriage shaft and a bearing which has been required conventionally can be (eliminated) changed to the rotational movement of a magnetic head (21). Since the carriage (22A) is not supported by both arms but supported by the single arm, the number of parts can be reduced in comparison with a conventional magnetic head actuator assembly. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a magnetic tape drive such as a linear tape storage system represented by DLT (Digital Linear Tape) and LTO (Linear Tape Open), and more particularly to a magnetic head actuator assembly that moves a magnetic head in a vertical direction by a voice coil motor. .

  This type of magnetic tape drive has been developed as a “backup” system for hard disks in computer systems, and various linear storage systems have been proposed. For example, a digital linear tape drive that functions as a DLT is disclosed in, for example, Patent Document 1.

  A digital linear tape drive (hereinafter also simply referred to as “drive device”, “tape drive”, or “drive”) receives a tape cartridge (hereinafter also simply referred to as “cartridge”) having a single reel (supply reel). It has a built-in take-up reel. When the tape cartridge is mounted on the drive device, the magnetic tape is pulled out of the tape cartridge and taken up by a take-up reel via a head guide assembly (HGA). The head guide assembly is for guiding a magnetic tape (hereinafter also simply referred to as “tape”) drawn from the tape cartridge to the magnetic head. The magnetic head exchanges information between the magnetic tape and the magnetic head. The head guide assembly is generally composed of an aluminum plate having a boomerang shape and six large guide rollers each using a bearing.

  The head guide assembly is also called a tape guide assembly, which is disclosed in, for example, Patent Document 2. An example of the guide roller is disclosed in Patent Document 3.

  In general, a magnetic tape drive includes a substantially rectangular parallelepiped housing having a common base, as described in, for example, Japanese Patent Application Laid-Open No. H10-228707. The base has two spindle motors (reel motors). The first spindle motor has a spool (take-up reel) permanently attached to the base, and the spool is sized to receive a magnetic tape flowing at a relatively high speed. The second spindle motor (reel motor) is adapted to receive a removable tape cartridge. The removable tape cartridge is manually or automatically inserted into the drive through a slot formed in the drive housing. When the tape cartridge is inserted into the slot, the cartridge is engaged with a second spindle motor (reel motor). Before rotating the first and second spindle motors (reel motors), the tape cartridge is connected to a permanently mounted spool (take-up reel) by a mechanical buckling mechanism. Many rollers (guide rollers) positioned between the tape cartridge and the permanent spool guide the magnetic tape as it moves back and forth at a relatively high speed between the tape cartridge and the permanently mounted spool. To do.

  In the digital linear tape drive having such a configuration, an apparatus is required for the take-up reel to pull the tape from the supply reel. Such a pulling device is disclosed in Patent Document 5, for example. According to this publication, a take-up reel is connected to a take-up leader means (first tape leader), and a supply tape leader means (second tape leader) is fixed to a tape on the supply reel. The first tape leader has a mushroom-like tab at one end thereof. The second tape leader has a locking hole. The tab is engaged with the locking hole.

  Furthermore, a mechanism for joining the first tape leader to the second tape leader is also required. Such a joining mechanism is disclosed in Patent Document 6, for example.

  Further, in Patent Document 7, the end of the leader tape (second tape leader) is locked to the tape end hooking portion of the tape cartridge without requiring an ear piece protruding to the side of the leader tape. The structure of the locking portion of the leader tape that can be used is disclosed.

  Patent Document 8 discloses a lock system for preventing a take-up reel of a tape drive from rotating when a tape cartridge is not inserted into the drive.

  The magnetic tape drive further includes a magnetic head actuator assembly, which is positioned between the take-up spool and the tape cartridge on a tape path defined by a plurality of rollers. In operation, the magnetic tape flows back and forth between the take-up spool and the tape cartridge and closely approaches the magnetic head actuator assembly while flowing over a defined tape path. An example of such a magnetic head actuator assembly is disclosed in Patent Document 4 above.

  On the other hand, an example of a tape cartridge mounted on a digital linear tape drive is disclosed in Patent Document 9.

  Patent Document 10 discloses a “tape drive” in which a tape leader is pushed from a tape cartridge to a take-up reel without using a buckling mechanism or a winding leader.

  The magnetic head actuator assembly includes a tape head assembly (hereinafter also simply referred to as “head assembly”) and a head feed mechanism. The head assembly includes a pair of flexible printed circuits (a head) that extends in the vertical direction, a head holder that holds the magnetic head, and a magnetic head that is electrically connected to an external circuit. FPC). The head holder is also called a carriage.

  On the other hand, the head feed mechanism is for moving the head assembly up and down while holding the head assembly. As disclosed in Patent Document 4, the conventional head feed mechanism includes a threaded lead screw (threaded shaft) and mechanically moves the head assembly up and down by rotating the lead screw. (Linear motion). In other words, a “mechanical linear actuator” is employed as a conventional head feed mechanism.

  In such a mechanical linear actuator, the position control of the head assembly is generally performed by open loop control. In the DLT, the storage capacity is increased. In “DLT1” which is the first generation DLT, the normal storage capacity is 40 GB, and the storage capacity when compressed is 80 GB. In addition, in “DLT2” that is the second generation DLT, the normal storage capacity is 80 Gbytes, and the compressed storage capacity is 160 Gbytes. In addition, in “DLT3” which is the third generation DLT, the normal storage capacity is about 150 Gbytes, and the compressed storage capacity is about 300 Gbytes. With a DLT having such a storage capacity, a mechanical linear actuator can sufficiently cope.

  However, “DLT4”, which is the next generation (fourth generation) DLT, has a normal storage capacity of 300 Gbytes, a compressed storage capacity of 600 Gbytes, and a large capacity (high storage density). For this reason, when the above-described mechanical linear actuator is used as a linear actuator for DLT having a large storage density, it is difficult to accurately control the head assembly to a desired position.

  On the other hand, in order to solve such problems in the mechanical linear actuator, an “electromagnetic linear actuator” that moves the head assembly up and down (linearly) electromagnetically is adopted as the head feed mechanism to control the position of the head assembly. Has been proposed for performing closed loop (feedback) control (see, for example, Patent Document 11). Since the electromagnetic linear actuator employs a feedback control method as a control method, the head assembly can always be accurately controlled to a desired position even if the magnetic tape fluctuates up and down during traveling. .

  Such an electromagnetic linear actuator generally includes a fixed portion, a movable portion that holds a head assembly (an object to be lifted) up and down along the vertical direction with respect to the fixed portion, and a movable portion of the movable portion. It has a guide for restraining (regulating) movement other than the (lifting / lowering) direction, and a base for attaching this guide.

  Here, the electromagnetic linear actuator can be divided into two types. The first type is a “movable magnet type” electromagnetic linear actuator, which includes a magnet in the movable part and a coil in the fixed part. The second type is a “movable coil type” electromagnetic linear actuator, which includes a magnet and a yoke in a fixed portion and a coil in a movable portion.

  As described above, the electromagnetic linear actuator is suitable as a DLT actuator having a large storage capacity. However, as described above, the control method (control system) is completely different between the mechanical linear actuator and the electromagnetic linear actuator. For this reason, when using this electromagnetic linear actuator as a DLT linear actuator of a lower model (namely, the first generation or the second generation), the control system for the mechanical linear actuator that has been incorporated up to that point is used at all. Therefore, a new control system suitable for the electromagnetic linear actuator must be incorporated. That is, it is necessary to change the design of the lower-level model DLT.

  In order to solve such problems, as a fourth generation (upper model) DLT linear actuator (head feed mechanism) compatible with lower model DLTs, not only mechanical linear actuators, but also electromagnetic A “composite linear actuator” that can also operate as a linear actuator is considered. That is, the composite linear actuator is a combination of a mechanical linear actuator and an electromagnetic linear actuator. In such a composite type linear actuator, a mechanical linear actuator is used for rough position control (open loop control) of the head assembly, and an electromagnetic linear actuator is used for precise position control (closed loop control). It can be carried out.

  More specifically, the composite linear actuator is a mechanical linear actuator including a lead screw having a rotation center shaft extending in the axial direction and a main movable portion that linearly moves in the axial direction by the rotation of the lead screw. Including. The main movable portion operates as an electromagnetic linear actuator including a sub-fixed portion and a sub-movable portion that linearly moves in the axial direction with respect to the sub-fixed portion by electromagnetic force. The electromagnetic linear actuator is constituted by a voice coil motor (VCM). Therefore, the sub-fixed part is called a VCM fixed part, and the sub-movable part is called a VCM movable part. The sub fixed portion has a yoke and a magnet, and the sub movable portion includes an air-core coil. The air-core coil is fixed to a head holder (attachment portion) that holds the magnetic head. Such composite linear actuators are disclosed in, for example, Patent Documents 12 to 15.

  The super DLT which is a kind of magnetic tape drive employs the electromagnetic linear actuator or the composite linear actuator as a linear actuator. In super DLT, the position of the magnetic tape is detected using an optical pickup.

  More specifically, the optical pickup is disposed to face the magnetic head with a magnetic tape interposed therebetween. The magnetic tape has a magnetic recording surface on the front surface side and a reflective surface on the back surface side. While the magnetic tape is running, the magnetic recording surface of the magnetic tape is in sliding contact with the magnetic head. On the other hand, a dot pattern for position detection is formed on the reflecting surface of the magnetic tape along the tape running direction. Each dot is made of a non-reflective material. The optical pickup detects the position of the magnetic tape by detecting the dot pattern formed on the reflecting surface of the magnetic tape. The optical pickup detects the position of the magnetic tape using a three-beam method well known in the art.

  In the LTO, a servo track is recorded in advance on the magnetic recording surface side of the magnetic tape in parallel with the data track, and the magnetic head reads the servo track so that the position of the magnetic head is changed to the magnetic tape. Control to the correct position on.

  In the composite linear actuator described above, the mechanical linear actuator may be referred to as a head feed mechanism, and the electromagnetic linear actuator may be referred to as a voice coil motor. That is, the head feed mechanism is for performing coarse adjustment of the position of the magnetic head by moving the head assembly up and down, and the voice coil motor is for performing fine adjustment of the position of the magnetic head.

  A magnetic tape drive 10 that is a DLT to which the present invention is applied will be described with reference to FIG. FIG. 1 is a perspective view of a magnetic tape drive 10 that is a DLT, with the top cover removed. Therefore, unlike the super DLT, the magnetic tape drive 10 shown in FIG. 1 does not have an optical pickup attached to the magnetic head actuator assembly. However, the DLT will be described because it is useful for understanding the present invention. .

  The magnetic tape drive 10 is for receiving a tape cartridge (not shown), and incorporates a take-up reel 11 therein. The take-up reel 11 is also called a spool. The tape drive 10 includes a substantially rectangular parallelepiped housing (chassis) 12 having a common base. The base has two spindle motors (reel motors) 13 and 14. The first spindle motor 13 has a spool (winding reel) 11 permanently attached to the base of the housing 12, and the spool 11 receives a magnetic tape (not shown) that flows at a relatively high speed. The size is determined. The second spindle motor (reel motor) 14 is adapted to receive a removable tape cartridge. The removable tape cartridge is inserted into the tape drive 10 manually or automatically through the slot 16 formed in the housing 12 of the tape drive 10 along the insertion direction indicated by the arrow A.

  When the tape cartridge is inserted into the slot 16, the tape cartridge engages with the second spindle motor (reel motor) 14. Before the first and second spindle motors (reel motors) 13 and 14 are rotated, the tape cartridge is permanently attached to a spool (take-up reel) 11 by a mechanical buckling mechanism (not shown). Connected. Many rollers (guide rollers) 15 positioned between the tape cartridge and the permanent spool 11 are used when the magnetic tape moves back and forth between the tape cartridge and the permanently attached spool 11 at a relatively high speed. To guide it.

  The housing 12 is constituted by a sheet metal press chassis or an aluminum die cast chassis made of an iron-based magnetic material.

  The magnetic tape drive 10 further includes a magnetic head actuator assembly 20, which is disposed on a tape path (not shown) defined by the plurality of rollers 15 between the take-up reel 11 and the tape cartridge. Positioned between. During operation, the magnetic tape flows back and forth between the take-up spool 11 and the tape cartridge and is in close proximity to the magnetic head actuator assembly 20 while flowing on the defined tape path.

  FIG. 2 shows a magnetic head actuator assembly 20A for super DLT. The main difference from the DLT magnetic head actuator assembly 20 shown in FIG. 1 is that in the super DLT magnetic head actuator assembly 20A, the optical pickup 30 is attached to the DLT magnetic head actuator assembly 20 via the arm 40. It is being done.

  The magnetic head actuator assembly 20 includes a magnetic head 21 that extends in the vertical direction, and a head holder (carriage) 22 that holds the magnetic head 21 so as to be movable in the vertical direction. The head holder 22 is moved in the vertical direction by a head feed mechanism described later.

  The arm 40 is attached to the lower end side of the head holder (carriage) 22 using screws or the like. As shown in FIG. 2, the arm 40 is substantially L-shaped, and the optical pickup 30 is attached to the top thereof.

  As shown in FIG. 2, the magnetic head 21 and the optical pickup 30 are disposed to face each other with a space between them. That is, the optical pickup 30 is disposed to face the magnetic head 21 with the magnetic tape 42 interposed therebetween. The magnetic tape 42 has a magnetic recording surface 42a and a reflection surface (irradiation surface) 42b opposite to the magnetic recording surface 42a. While the magnetic tape 42 is running, the magnetic recording surface 42 a of the magnetic tape 42 is in sliding contact with the magnetic head 21. On the other hand, a dot pattern for position detection is formed on the reflecting surface 42b of the magnetic tape 42 along the tape running direction. Each dot is made of a non-reflective material. The optical pickup 30 detects the position of the magnetic tape 42 by detecting the dot pattern formed on the reflection surface 42 b of the magnetic tape 42. The optical pickup 30 detects the position of the magnetic tape using a three-beam method well known in this technical field.

  The optical pickup 30 includes a hologram unit 31, a diaphragm 33, a lens 35, and a lens holder 37. The lens holder 37 is hollow and holds the lens 35 therein. The hologram unit 31 is attached to one end of the lens holder 37. The diaphragm 33 is disposed between the hologram unit 31 and the lens 35.

  The hologram unit 31 includes a chip 311, a hologram 313, and a diffraction grating 315.

  Hereinafter, a conventional magnetic head actuator assembly 20 will be described with reference to FIGS. Since the illustrated magnetic head actuator assembly 20 is for DLT, the optical pickup 30 may be attached via the arm 40 as shown in FIG. The illustrated magnetic head actuator assembly 20 is a composite linear actuator. However, the illustrated composite linear actuator is different from those disclosed in Patent Documents 12 to 15, and the magnetic head 21 is linearly moved in the width direction of the magnetic tape 42 using a bearing (bearing) as described later. It is moved.

  FIG. 3 is an exploded perspective view of the magnetic head actuator assembly (composite linear actuator) 20. FIG. 4 is a perspective view showing the appearance of the magnetic head actuator assembly 20 as seen from the front side. FIG. 5 is a perspective view showing the appearance of the magnetic head actuator assembly 20 as seen from the back side. FIG. 6 is a plan view of the magnetic head actuator assembly 20. FIG. 7 is a front view of the magnetic head actuator assembly 20. 8 is a sectional view taken along line VIII-VIII in FIG. 9 is a cross-sectional view taken along line IX-IX in FIG. FIG. 10 is an enlarged detailed view showing a portion C in FIG. FIG. 11 is a right side view of the magnetic head actuator assembly 20. 3 to 11, the flexible printed circuit (FPC) is omitted. Further, as shown in FIG. 3, coordinate axes orthogonal to each other are represented by an X axis, a Y axis, and a Z axis. Here, the X-axis direction is the left-right direction, the Y-axis direction is the front-rear direction, and the Z-axis direction is the up-down direction.

  The magnetic head actuator assembly 20 includes a magnetic head 21 that extends in the vertical direction, and a head holder (carriage) 22 that holds the magnetic head 21 so as to be movable in the vertical direction. The magnetic head 21, the carriage 22, and the flexible printed circuit constitute a head assembly. The head holder 22 is moved in the vertical direction by a head feed mechanism described below.

  The carriage 22 includes a carriage body 221, a head mounting portion 222 provided on the front surface of the carriage body 221 for mounting the magnetic head 21, and a carriage shaft 223 extending from the carriage body 221 in the left-right direction. The carriage body 221 is formed with a through hole 221a through which the linear bearing shaft 224 penetrates in the vertical direction. Therefore, the head assembly and the head feed mechanism described below are assembled through the linear bearing shaft 224.

  The head feed mechanism includes a threaded lead screw 51 having a rotation center axis extending in the vertical direction as a rotation member, and a head lift body that moves up and down along the rotation center axis as the lead screw 51 rotates as a linear movement member. 52 and a backlash prevention mechanism 53 for preventing backlash of the magnetic head actuator assembly 20.

  The lead screw 51 has a lead screw gear 54 that rotates the lead screw 51 around the rotation center axis by other driving means (for example, a stepping motor) on the lower end side thereof.

  The head lift body 52 has a substantially rectangular parallelepiped shape, and a semi-cylindrical opening (not shown) is formed on the back side. The head lift body 52 moves the head assembly up and down while holding the head assembly up and down. That is, the head lift body 52 supports the magnetic head 21 so as to be movable up and down. A backlash prevention mechanism is disposed inside the semi-cylindrical opening of the head lift body 52.

  The backlash prevention mechanism includes a preload bushing 531 having a thread groove that engages with the lead screw 51 and a preload spring 532 when the backlash prevention mechanism is disposed inside the semi-cylindrical opening of the head lift body 52.

  The lead screw 51 engages with a thread groove of a bearing 55 provided in the head lift body 52. The rotation of the lead screw 51 around the rotation center axis moves the head lift body 52 in the vertical direction, which is the direction in which the rotation center axis extends, in cooperation with the backlash prevention mechanism. A substantially U-shaped guide portion 57 is attached to the lower surface of the head lift body 52. The guide portion 57 is fitted into a guide bar (not shown) and attached so as to be slidable in the vertical direction, and prevents the head lift body 52 from rotating.

  The head lift body 52 has a center shaft 521 extending in the left-right direction from both side surfaces on the front side. The head lift body 52 has a pair of protrusions 522 extending forward from the upper surface and the lower surface, and the pair of protrusions 522 are through holes into which both ends of the linear bearing shaft 244 are inserted. 522a is formed.

  The head lift body 52 is attached with a magnetic circuit (magnet or yoke) that constitutes a sub-fixing portion of an electromagnetic linear actuator (voice coil motor).

  More specifically, the magnetic circuit includes a magnet 61 that is magnetized in the plate thickness direction and in opposite directions at the upper and lower portions, a center yoke 62 attached to the back surface of the head lift body 52, and a back yoke 63. The back yoke 63 has a main surface that is disposed in parallel and spaced apart from the center yoke 62, and an upper end portion 631 and a lower end portion 632 are bent substantially at right angles to the main surface by pressing. That is, the back yoke 63 has a U-shaped cross section. The upper end 631 and the lower end 632 of the back yoke 63 are in contact with the upper end and the lower end of the center yoke 62, respectively. The magnet 61 is attached in contact with the main surface (inner surface) of the back yoke 63.

  The center yoke 62 has an upper notch 62a and a lower notch 62b at the upper end and the lower end, respectively. Further, the upper end portion 631 of the back yoke 63 has an upper end convex portion 631 a that fits into the upper notch portion 62 a of the center yoke 62, and the lower end portion 632 of the back yoke 62 fits into the lower notch portion 62 b of the center yoke 62. It has a lower end convex part 632a.

  The head lift body 52 has a pair of upper projections 523 for hooking a leaf spring member 66 described later at both corners on the back side of the upper surface. Further, although not shown, the head lift body 52 has one lower protrusion for hooking the leaf spring member 66 in the vicinity of the root where the guide portion 57 on the back side of the lower surface extends.

  The leaf spring member 66 is for fixing the back yoke 63 of the magnetic circuit to the head lift body 52. More specifically, the leaf spring member 66 has a U-shaped cross section so as to cover the back yoke 63 from the back side. The plate spring member 66 includes an upper surface portion 661 that covers the upper end portion 631 of the back yoke 63, a lower surface portion 662 that covers the lower end portion 632 of the back yoke 63, and an upper surface portion 661 and a lower surface portion 662 that cover the back surface of the back yoke 63. And a pair of ears 664 extending from the connection part 663 in the left-right direction and used for stably assembling a flexible printed circuit (not shown). The illustrated leaf spring member 66 is made of metal.

  The upper surface portion 661 has an upper hole 661b into which the upper protrusion 523 of the head lift body 52 is inserted. On the other hand, the lower surface portion 662 has a lower hole 662b into which the lower protrusion of the head lift body 52 is inserted. The connecting portion 663 has a spring tongue piece 663 a that is bent forward at the center thereof and applies pressure to the back surface of the back yoke 63.

  When the back yoke 63 constituting the magnetic circuit is fixed to the head lift body 52, the back yoke 63 is attached to the head by hooking the upper hole 661b and the lower hole 662b to the upper protrusion 523 and the lower protrusion of the head lift body 52, respectively. It can be fixed to the lift body 52.

  Next, the sub movable part of the electromagnetic linear actuator (voice coil motor) will be described.

  The sub movable portion includes a coil 71 disposed between the magnet 61 of the magnetic circuit and the center yoke 62, a coil holder 72 for holding the coil 71, and a pair of arms provided on both side surfaces of the head lift body 52. 73.

  More specifically, the coil holder 72 has a substantially rectangular shape that is long in the left-right direction. Cutouts 72 a are formed at the left and right ends of the coil holder 72. In addition, two screw holes 72b are formed on the left and right ends of the coil holder 72 in the vertical direction with a notch 72a therebetween.

  On the other hand, the pair of arms 73 has a rectangular parallelepiped shape that is substantially long in the front-rear direction. On the back surface of the pair of arms 73, a protrusion 73 a that fits into the notch 72 a of the coil holder 72 is formed. In addition, both ends of the coil holder 72 are fixed to the back surfaces of the pair of arms 72 with four screws 74 through four screw holes 72b.

  Further, a through hole 73 b through which the center shaft 521 of the head lift body 52 passes is formed in front of the center of the pair of arms 73. In other words, the pair of arms 73 is attached to the center shaft 521 of the head lift body 52 via the pair of bearings 75, the spring 76, and the retaining member 77 so as to be rotatable around the center shaft 521.

  Further, a through hole 73 c through which the carriage shaft 223 of the carriage 22 passes is formed at the front end portions of the pair of arms 73. That is, the pair of arms 73 supports the carriage 22 so as to be rotatable around the carriage shaft 223 via the pair of bearings 78.

  As described above, the movement of the carriage 22 is restricted by the linear bearing shaft 224 so as to be movable only in the vertical direction. Accordingly, when the pair of arms 73 rotate around the center shaft 521 of the head lift body 52, the carriage (head holder) 22 moves up and down along the linear bearing shaft 224.

  The magnetic circuit (61, 62, 63), the coil 71, and the coil holder 72 constitute a voice coil motor. In other words, the voice coil motor is provided on the back side of the head lift body 52 and rotates the pair of arms 73 around the center shaft 521. Anyway, the voice coil motor is for moving the magnetic head 21 up and down. In the conventional magnetic head actuator assembly 20, the carriage (head holder) 22 is supported with respect to the head lift body 52 by both arms so as to be movable up and down.

JP-A-9-198639 Japanese National Patent Publication No. 9-500753 JP 2000-100025 A JP 2000-501547 A Japanese Patent Publication No. 3-7595 Japanese Patent Publication No. 6-39027 JP 2000-100116 A Japanese Patent Laid-Open No. 11-86381 JP 2000-149491 A Japanese Patent Laid-Open No. 11-316991 JP 2002-198219 A JP 2004-87654 A JP 2004-87050 A JP 2004-86967 A JP 2004-86973 A

  In the magnetic head actuator assembly (composite type linear actuator) 20 having such a structure, it is necessary to escape at the rotating portion (the carriage shaft 223 and the bearing 78) that converts the rotational motion of the pair of arms 73 into the linear motion of the carriage 22. .

  However, when the clearance of the rotating portion is a gap, as shown in FIG. 10, rattling occurs between the carriage shaft 223 and the bearing 78. This rattling causes problems such as vibrations and the problem that the rotational force of the arm 73 is not completely transmitted. That is, it becomes difficult to stabilize the characteristics of the magnetic head actuator assembly.

  Conversely, if there is no gap between the carriage shaft 223 and the bearing 78, there is a problem that a load is applied.

  Accordingly, it is an object of the present invention to provide a magnetic head actuator assembly that can suppress backlash at a rotating portion that converts rotational motion into linear motion.

  Another object of the present invention is to provide a magnetic head actuator assembly capable of stabilizing characteristics.

  Other objects of the invention will become apparent as the description proceeds.

  According to the present invention, the magnetic head (21), a carriage for holding the magnetic head, the carriage (22A) having a carriage shaft (223) extending in one left-right direction, and the carriage A head lift body that moves the magnetic head up and down while holding it vertically movable, the head lift body (52) having a center shaft (521) extending in the left-right direction, and the carriage of the head lift body One arm provided on one side surface provided with a shaft and rotatably supported around the center shaft, and supports the carriage rotatably around the carriage shaft at a tip portion. Both ends are supported on the front side of the head lift body through the arm (73) and the carriage in the vertical direction. A linear bearing shaft (224); and a voice coil motor (61, 62, 63, 71, 72A) provided on the back side of the head lift body for rotating the arm around the center shaft. A magnetic head actuator assembly is obtained.

  In the magnetic head actuator assembly, the voice coil motor holds a magnetic circuit (61, 62, 63) fixed to the head lift body, a coil (71) disposed in the magnetic circuit, and the coil. A coil holder part extending in the left-right direction, the coil holder part (721) coupled to the arm at one end of the one side surface, and the other of the head lift body from the other end of the coil holder part It may have an arm portion (722) that extends along the side surface and is rotatably supported around the center shaft. In this case, it is preferable that the coil holder part (721) and the arm part (722) are integrally formed. Further, the arm portion has a through hole (73c) through which the center shaft penetrates at a tip portion thereof, and the arm portion receives the center shaft (via a bearing (75) provided in the through hole. 521) is preferably pivotably mounted.

  The reference numerals in the parentheses are given for ease of understanding, and are merely examples, and of course are not limited thereto.

  In the present invention, since the carriage is supported by the head lift body with one arm so as to be movable up and down, the gap between the carriage shaft and the bearing, which has been conventionally required, is eliminated (changed) to the rotational movement of the magnetic head. be able to. Further, by supporting the carriage with one arm instead of both arms, the number of parts can be reduced as compared with the conventional magnetic head actuator assembly.

  A magnetic head actuator assembly 20B according to the first embodiment of the present invention will be described with reference to FIGS. Since the illustrated magnetic head actuator assembly 20B is for DLT, the optical pickup 30 can be attached via the arm 40 as shown in FIG. The illustrated magnetic head actuator assembly 20B is a composite linear actuator, and the magnetic head 21 is linearly moved in the width direction of the magnetic tape 42 using a bearing.

  FIG. 12 is an exploded perspective view of the magnetic head actuator assembly (composite linear actuator) 20B. FIG. 13 is a perspective view showing the appearance of the magnetic head actuator assembly 20B as seen from the front side. FIG. 14 is a perspective view showing the appearance of the magnetic head actuator assembly 20B as seen from the back side. FIG. 15 is a plan view of the magnetic head actuator assembly 20B. FIG. 16 is a front view of the magnetic head actuator assembly 20B. 17 is a sectional view taken along line XVII-XVII in FIG. FIG. 18 is a left side view of the magnetic head actuator assembly 20B.

  12 to 18, the flexible printed circuit (FPC) is omitted. In addition, as shown in FIG. 12, coordinate axes orthogonal to each other are represented by an X axis, a Y axis, and a Z axis. Here, the X-axis direction is the left-right direction, the Y-axis direction is the front-rear direction, and the Z-axis direction is the up-down direction.

  The illustrated magnetic head actuator assembly 20B has only one arm 73 on the right side, except that the coil holder 72 is changed to the coil holder arm 72A and the carriage (head holder) is changed as described later. Thus, the magnetic head actuator assembly 20 shown in FIGS. 3 to 11 has the same configuration and functions similarly. Accordingly, the reference numeral 22A is given to the carriage (head holder). Components having the same functions as those of the components of the conventional magnetic head actuator assembly 20 are denoted by the same reference numerals, and the description thereof is omitted for the sake of simplicity.

  Unlike the conventional carriage 22, the carriage 22 </ b> A has only one carriage shaft 223 (in the illustrated example, only the left-side carriage shaft 223). In other words, the carriage 22A has no carriage shaft in the right direction. One arm 73 is also provided only on one side of the head lift body 52 (in the illustrated example, only on the left side of the head lift body 52). As the carriage shaft 223 and the bearing 78, those having substantially no gap between them are used.

  On the other hand, the coil holder arm 72A has a substantially L-shaped shape, and includes a coil holder portion 721 extending in the left-right direction and an arm portion 722 extending forward from the left end portion of the coil holder portion 721. Consists of A notch 72 a is formed at the left end of the coil holder portion 721. Then, two screw holes 72b are formed on the left end portion of the coil holder portion 721 with the notch portion 72a interposed therebetween. A through hole 73 b through which the center shaft 521 of the head lift body 52 passes is formed at the tip of the arm portion 722. That is, the arm portion 722 is attached to the center shaft 521 of the head lift body 52 via the bearing 75 so as to be rotatable around the center shaft 521.

  Anyway, in the magnetic head actuator assembly 20B according to the present embodiment, the carriage (head holder) 22A is supported by the head lift body 52 so as to be movable up and down with one arm.

  As is clear from the above description, in the present embodiment, the magnetic circuit (61, 62, 63), the coil 71, and the coil holder arm 72A constitute a voice coil motor.

  In the magnetic head actuator assembly 20B having such a structure, when one arm 73 rotates around the center shaft 521 of the head lift body 52 as shown by an arrow B in FIG. 18, the carriage (head holder) 22A. Moves up and down along the linear bearing shaft 224 as indicated by arrow C in FIG. At this time, as indicated by an arrow D in FIG. 15, the carriage 22 </ b> A (magnetic head 21) rotates around the linear bearing shaft 224 by a slight angle. Since the angle range of the rotating magnetic head 21 is very small (for example, about 0.2 °), reading / writing on the magnetic tape 42 of the magnetic head 21 is not adversely affected.

  As described above, in the present invention, the support at the rotating portion that converts the rotational motion into the linear motion is made to be one arm 73, thereby eliminating (eliminating) the gap between the carriage shaft 223 and the bearing 78, which has been conventionally required. The rotational movement of the magnetic head 21 can be changed. By supporting the carriage 22A with one arm instead of both arms, the number of parts can be reduced as compared with the conventional magnetic head actuator assembly 20.

  Although the present invention has been described with reference to preferred embodiments, it is obvious that various modifications can be made by those skilled in the art without departing from the spirit of the present invention. For example, in the above-described embodiment, the coil holder portion 721 and the arm portion 722 are integrally formed as the coil holder arm 72A, but the coil holder portion and the arm portion may be configured separately. In the above-described embodiment, the arm is provided on the left side surface of the head lift body, but may be provided on the right side surface. In this case, the carriage shaft extends only in the right direction of the carriage, and the configuration of the coil holder arm may be changed so that the arm portion is provided on the left side surface of the head lift body. Furthermore, in the above-described embodiment, only the example in which the composite linear actuator is adopted as the magnetic head actuator assembly has been described. However, it is obvious that the present invention can be applied to the electromagnetic linear actuator as well.

1 is a perspective view showing a magnetic tape drive including a magnetic head actuator assembly for DLT to which the present invention is applied, with a top cover removed. FIG. It is a partial cross section front view which shows the structure of the magnetic head actuator assembly for super DLT. It is a disassembled perspective view of the conventional magnetic head actuator assembly (composite type linear actuator). FIG. 4 is a perspective view showing the appearance of the magnetic head actuator assembly shown in FIG. 3 as viewed from the front side. FIG. 4 is a perspective view showing an appearance of the magnetic head actuator assembly shown in FIG. 3 as viewed from the back side. FIG. 4 is a plan view of the magnetic head actuator assembly shown in FIG. 3. FIG. 4 is a front view of the magnetic head actuator assembly shown in FIG. 3. It is VIII-VIII sectional drawing in FIG. It is IX-IX sectional drawing in FIG. FIG. 10 is an enlarged detailed view of a portion A in FIG. 9. FIG. 4 is a right side view of the magnetic head actuator assembly shown in FIG. 3. 1 is an exploded perspective view of a magnetic head actuator assembly (composite linear actuator) according to an embodiment of the present invention. FIG. 13 is a perspective view showing an appearance of the magnetic head actuator assembly shown in FIG. 12 as viewed from the front side. FIG. 13 is a perspective view showing an appearance of the magnetic head actuator assembly shown in FIG. 12 as viewed from the back side. FIG. 13 is a plan view of the magnetic head actuator assembly shown in FIG. 12. FIG. 13 is a front view of the magnetic head actuator assembly shown in FIG. 12. It is XVII-XVII sectional drawing in FIG. FIG. 13 is a right side view of the magnetic head actuator assembly shown in FIG. 12.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Magnetic tape drive 20B Magnetic head actuator assembly 21 Magnetic head 22A Head holder (carriage)
223 Carriage shaft 224 Linear bearing shaft 52 Head lift body 521 Center shaft 61 Magnet 62 Center yoke 63 Back yoke 71 Coil 72A Coil holder arm 721 Coil holder portion 722 Arm portion 73c Through hole 75 Bearing

Claims (4)

  A magnetic head, a carriage for holding the magnetic head, the carriage having a carriage shaft extending in one direction in the left-right direction, and a head for moving the magnetic head up and down while holding the carriage up and down The lift body is provided on one side of the head lift body having a center shaft extending in the left-right direction and the carriage shaft of the head lift body, and is rotatable around the center shaft. One arm to be supported, the arm supporting the carriage so as to be rotatable around the carriage shaft at a tip, and both ends on the front side of the head lift body penetrating the carriage vertically. A linear bearing shaft on which the portion is supported, and provided on the back side of the head lift body, And having a voice coil motor for rotating the arm around said center shaft, a magnetic head actuator assembly.   The voice coil motor includes a magnetic circuit fixed to the head lift body, a coil disposed in the magnetic circuit, and a coil holder portion extending in a left-right direction for holding the coil, The coil holder part coupled to the arm at one end of the coil side, and extends along the other side of the head lift body from the other end of the coil holder part, and is rotatably supported around the center shaft The magnetic head actuator assembly according to claim 1, wherein the magnetic head actuator assembly has an arm portion.   The magnetic head actuator assembly according to claim 2, wherein the coil holder part and the arm part are integrally formed. The arm portion has a through-hole through which the center shaft passes at a tip portion thereof, and the arm portion is rotatably attached around the center shaft through a bearing provided in the through-hole. The magnetic head actuator assembly according to claim 2, wherein the magnetic head actuator assembly is a magnetic head actuator assembly.

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