JP2007200451A - Electromagnetic type linear actuator, head mounting structure, and head mounting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cost in a head holding part for mounting head assemblies and to improve mounting accuracy of the head assemblies on a head mounting part. <P>SOLUTION: The movable part of this electromagnetic type linear actuator has the head holding part (63A) holding the head assemblies (17a and 17b). The head holding part has the head mounting part (631A) for mounting the head assemblies. The head mounting has three head mounting faces (631b) for mounting the head assemblies at three positions. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a recording / reproducing apparatus represented by DLT (Digital Linear Tape) and LTO (Linear Tape Open), and in particular, an electromagnetic linear actuator that can be used as a head feed mechanism of a magnetic head actuator assembly used therein, The present invention relates to a head mounting structure and method for mounting a head assembly to a head mounting portion.

  This type of recording / reproducing apparatus has been developed for computer system backup, and various recording / reproducing apparatuses have been proposed. For example, a recording / reproducing apparatus that functions as a DLT is disclosed in Patent Document 1, for example.

  A recording / reproducing apparatus (hereinafter 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 tape drive includes a substantially rectangular parallelepiped housing having a common base, as described in, for example, Patent Document 4. The base has first and second 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.

  The digital linear tape drive having such a configuration requires a device 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 Patent Document 5, 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 the take-up reel of the tape drive from rotating when the 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).

  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 permanent magnet and a yoke member 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 has been proposed. 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 includes a magnetic circuit including a yoke member and a permanent 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 a composite linear actuator is disclosed in, for example, Patent Document 12 and Patent Document 13.

  The present invention relates to a composite linear actuator, and more particularly to an electromagnetic linear actuator used in a composite linear actuator. In this electromagnetic linear actuator, as described above, the sub-fixed portion includes a magnetic circuit including a yoke member and a permanent magnet. The yoke member includes a yoke base, a center yoke provided at the center of the yoke base, and an upper yoke provided at the upper part of the yoke base. The permanent magnet is composed of a pair of plate magnets housed in a yoke base. The yoke base and the upper yoke are collectively called an outer yoke.

  The sub movable portion is supported by a sub fixing portion including a magnetic circuit through a support means so as to be movable. As such a support means, an upper leaf spring and a lower leaf spring are used which fix the sub movable portion to the sub fixed portion so as to be linearly movable.

  Note that a recording / reproducing apparatus serving as an LTO is disclosed in Patent Document 14. In LTO, a composite linear actuator having the same structure as that used in DLT is used. In 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 to thereby position the magnetic head on the magnetic tape. Control to the correct position.

  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.

  As described above, at present, this type of recording / reproducing apparatus (tape drive) is characterized by large capacity, high density, and high speed. For this reason, a magnetic head that reads from and writes to a magnetic tape must be moved at the same time while positioning with high accuracy according to the speed of the tape by a small actuator composed of an electromagnetic linear actuator.

  As such a small actuator, a cylindrical outer yoke using magnetic material, a magnet fixed to the inner peripheral surface of the outer yoke, and a cylindrical inner yoke using magnetic material, and thrust generation There is known a VCM type electromagnetic linear actuator composed of a movable part having a coil as a part (see, for example, Patent Document 15).

  On the other hand, in a recording / reproducing apparatus (tape drive), a magnetic head that reads / writes from / to the tape is fixed to an auxiliary movable part of a small actuator (electromagnetic linear actuator) with an adhesive.

  A method of attaching the magnetic head 17a to the sub movable portion will be described with reference to FIGS. FIG. 1 is a perspective view showing a state in which the magnetic head 17a is attached to the head holding portion 63 of the sub movable portion, and FIG. 2 is an exploded perspective view thereof.

  As shown in FIG. 1, 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-back direction, and the Z-axis direction is the up-down direction (axial direction).

  The magnetic head 17a extends in the vertical direction (vertical direction) Z. The magnetic head 17a is held by a head holding plate 17b. The magnetic head 17a and the head holding plate 17b constitute a head assembly. The head holding plate 17b is joined to the head holding part 63 of the sub movable part by an adhesive. Specifically, the head holding portion 63 has a head attachment portion 631 for attaching the head assembly to the front thereof. The head mounting portion 631 has one head mounting surface 631a on the entire front surface thereof. The magnetic head 17a is fixed to the head mounting surface 631a with an adhesive via the head holding plate 17b.

  The head mounting portion 631 has a pair of protrusions 633 that are spaced apart in the vertical direction Z and protrude forward. On the other hand, the head holding plate 17b has a pair of through holes (not shown) into which the pair of protrusions 633 are inserted. As a result, the head assembly (17a, 17b) is positioned in the Z-axis direction (vertical direction). That is, the combination of the pair of protrusions 633 and the pair of through holes serves as an up-down direction positioning unit that determines the position in the Z-axis direction (up-down direction) in the head assembly.

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 2002-233127 A JP 2004-86973 A JP 2004-87654 A JP-T-2002-530794 Japanese Examined Patent Publication No. 1-2668

  In the conventional head mounting structure as shown in FIGS. 1 and 2, the X-axis direction (left-right direction), Y-axis direction (front-rear direction), rotation direction about the X-axis, and rotation about the Y-axis of the magnetic head 17a It is difficult to accurately perform positioning in the rotation direction. In order to improve the positioning accuracy, it is necessary to improve the processing accuracy of the head mounting surface 631a of the head mounting portion 631 in the head holding portion 63, and the manufacturing cost of the head holding portion 63 increases.

  Further, even if the entire head mounting surface 631a of the head mounting portion 631 in the head holding portion 63 is processed and its accuracy is improved, depending on the amount of adhesive applied to mount the magnetic head 17a to the head mounting surface 631a, There is a possibility that the magnetic head 17a is inclined with respect to the head mounting surface 631a. Therefore, it is necessary to manage the application amount of the adhesive.

  An object of the present invention is to provide an electromagnetic linear actuator, a head mounting structure, and a head mounting method capable of manufacturing a head holding portion for mounting a head assembly at low cost.

  Another object of the present invention is to provide an electromagnetic linear actuator, a head mounting structure, and a head mounting method capable of improving the mounting accuracy of a head assembly to a head mounting portion.

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

  According to the first aspect of the present invention, an electromagnetic linear actuator comprising a fixed portion (172, 70) and a movable portion (60) that linearly moves in the axial direction (Z) with respect to the fixed portion by electromagnetic force. (50), the movable part has a head holding part (63A) for holding the head assembly (17a, 17b), and the head holding part has a head attaching part (631A) for attaching the head assembly. The head mounting portion has N head mounting surfaces (631b) for mounting the head assembly at N locations (N is an integer equal to or greater than 2), whereby an electromagnetic linear actuator can be obtained.

  In the electromagnetic linear actuator according to the first aspect of the present invention, the axial direction may be a vertical direction (Z) of the electromagnetic linear actuator. In this case, the head assembly may be composed of a magnetic head (17a) extending in the vertical direction and a head holding plate (17b) for holding the magnetic head, and the head holding plate is the N Each head mounting surface may be fixed by an adhesive. The N is preferably 3. In this case, one of the three head mounting surfaces (631b) may be provided at the upper end of the head mounting portion, and the other two may be provided at the lower end of the head mounting surface. The electromagnetic linear actuator preferably further includes vertical positioning means (633, 17b-1) for determining a position in the vertical direction (Z) in the head assembly (17a, 17b). The vertical positioning means is, for example, a pair of protrusions (633) protruding from the head mounting portion and spaced apart from each other in the vertical direction, and the head holding plate is inserted so that the pair of protrusions are inserted. And a pair of through holes (17b-1).

  According to the second aspect of the present invention, there is provided a head mounting structure for mounting the head assembly (17a, 17b) to the head mounting portion (631A), wherein the head mounting portion includes N head assemblies (N is 2). A head mounting structure having N head mounting surfaces (631b) for mounting with the above integers) is obtained.

  In the head mounting structure according to the second aspect of the present invention, the head assembly includes a magnetic head (17a) extending in the vertical direction (Z) and a head holding plate (17b) for holding the magnetic head. May be configured. In this case, the head holding plate is fixed by an adhesive on the N head mounting surfaces. The N is preferably 3. In this case, one of the three head mounting surfaces (631b) may be provided at the upper end of the head mounting portion, and the other two may be provided at the lower end of the head mounting surface. The head mounting structure preferably further includes vertical positioning means (633, 17b-1) for determining the vertical position of the head assembly. The vertical positioning means is, for example, a pair of protrusions (633) protruding from the head mounting portion and spaced apart from each other in the vertical direction, and the head holding plate is inserted so that the pair of protrusions are inserted. And a pair of through holes (17b-1).

  According to a third aspect of the present invention, there is provided a head mounting method for mounting the head assembly (17a, 17b) to the head mounting portion (631A), wherein the head assembly is mounted at N locations (N is 2 or more). The head mounting method includes a step of forming N head mounting surfaces (631b) for mounting at an integer and a step of fixing the head assembly to the N head mounting surfaces with an adhesive.

  In the head mounting method according to the second aspect of the present invention, the head assembly includes a magnetic head (17a) extending in the vertical direction (Z) and a head holding plate (17b) for holding the magnetic head. May be configured. In this case, the head holding plate is fixed by the adhesive on the N head mounting surfaces. The N is preferably 3. The step of forming the N head mounting surfaces may be performed by machining. The head mounting portion may be made of a resin material. In this case, the step of forming the N head mounting surfaces is preferably performed by injection molding using a mold having a cavity corresponding to the head mounting portion having the N head mounting surfaces.

  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 head mounting portion of the head holding portion has N head mounting surfaces for mounting the head assembly at N locations, the head holding portion can be manufactured at low cost, and the head mounting portion of the head assembly can be manufactured. Mounting accuracy can be improved.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a tape drive 10 as a recording / reproducing apparatus to which the present invention is applied will be described with reference to FIGS. FIG. 3 is a perspective view of the tape drive 10 with the upper lid removed as viewed from the upper surface side. FIG. 4 is a perspective view of the tape drive 10 shown in FIG. 3 as viewed from the lower surface side.

  The tape drive 10 is for receiving the cartridge 20 and has a take-up reel 11 built 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 first and second spindle motors (reel motors). The first spindle motor 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) flowing at a relatively high speed. The size is fixed. A second spindle motor (reel motor) 13 is adapted to receive a removable cartridge 20. The removable cartridge 20 is inserted into the tape drive 10 through the cartridge holder 14 formed in the housing 12 of the tape drive 10 along the insertion direction indicated by the arrow A.

  When the cartridge 20 is inserted into the cartridge holder 14, the cartridge 20 is automatically loaded after being engaged with the cartridge holding mechanism 15, and the cartridge 20 is engaged with the second spindle motor (supply reel motor) 13. Before rotating the first and second spindle motors (reel motors), the cartridge 20 is permanently attached to the cartridge 20 by a grabber (not shown) and a leader pin (not shown). 11 is connected. Many rollers (guide rollers) 16 positioned between the cartridge 20 and the permanent spool 11 are used when the magnetic tape moves back and forth between the cartridge 20 and the permanently attached spool 11 at a relatively high speed. Guide it.

  The tape drive 10 further includes a head actuator 17 having a magnetic head 17a. The head actuator 17 is positioned between the take-up reel 11 and the cartridge 20 on a tape transfer path (not shown) defined by the plurality of rollers 16. During operation, the magnetic tape flows back and forth between the take-up reel 11 and the cartridge 20 and is in close proximity to the head actuator 17 while flowing on the defined tape transport path.

  The tape drive 10 has a first switch SW <b> 1 provided on the main surface of the chassis 12 on the front right side. The first switch SW1 is for detecting a position at which automatic loading is started after the cartridge 20 is inserted into the cartridge holder 14. The first switch SW1 is composed of a photo interrupter. The cartridge holder 14 has a first shielding plate (not shown) for shielding the first switch SW1.

  The tape drive 10 includes a mode motor 30 on the main surface of the chassis 12. The mode motor 30 is connected to a mode gear 32 on the back side of the chassis 12 via seven reduction gears 31 (only three reduction gears are shown in FIG. 3). A sensor substrate 34 is provided on the back side of the chassis 12 so as to face the mode gear 32. Anyway, the mode gear 32 is driven by the mode motor 30.

  As shown in FIG. 3, the tape drive 10 includes a second switch SW <b> 2 for detecting that the cartridge 20 is correctly received (inserted) in the cartridge holder 14. The second switch SW2 is also a photo interrupter. The tape drive 10 includes a cartridge holder locking mechanism 36 for locking the cartridge holder 14. The cartridge holder locking mechanism 36 is for preventing the cartridge holder 14 from moving in the insertion direction A unless the cartridge 20 is correctly inserted into the cartridge holder 14. Therefore, when the cartridge 20 is correctly inserted into the cartridge holder 14, the cartridge holder 14 is unlocked by the cartridge holder locking mechanism 36, and the cartridge holder 14 can move in the insertion direction A. The cartridge holder locking mechanism 36 includes a second shielding plate 361 for shielding the second switch SW2.

  As shown in FIG. 4, the tape drive 10 includes a gear cam 38 that meshes with the mode gear 32. The gear cam 38 is also called a cam gear. The gear cam 38 has a cam groove which will be described later.

  As shown in FIG. 3, the tape drive 10 includes an arm housing 40 that is rotatably provided around a rotation shaft 401 on the main surface of the chassis 12. The arm housing 40 has a horizontal arm 402 extending in the horizontal direction and a vertical arm 403 extending in the vertical direction. An engaging pin 402 a is provided at the tip of the horizontal arm 402, and an engaging pin 403 a is provided at the lower end of the vertical arm 403. The engagement pin 403a engages with the cam groove of the gear cam 38.

  The tape drive 10 also includes a cam slider 42 that is formed integrally with the cartridge holder 14. The cam slider 42 has a slider opening 421 extending in a direction orthogonal to the insertion direction A. The engagement pin 402 a of the horizontal arm 402 of the arm housing 40 described above is inserted into the slider opening 421.

  Therefore, the cartridge holder 14 that holds the cartridge 20 is connected to the mode gear 32 via the cam slider 42, the arm housing 40, and the gear cam 38. The combination of the mode motor 30, the mode gear 32, and the cartridge holder 14 serves as an ejection mechanism that abuts the cartridge 20 accommodated in the tape drive 10 against the cartridge 20 and ejects it out of the tape drive 10.

  When the cartridge 20 is inserted into the cartridge holder 14, the cartridge 20 is held by the cartridge holder 14 via the cartridge holding mechanism 15. When the cartridge 20 is completely inserted into the cartridge holder 14, the cartridge 20 is engaged by the cartridge holding mechanism 15.

  The cartridge holder 14 is movable only along the insertion direction A by guide means described later. The cartridge holding mechanism 15 is movable along the L-shaped path by the guide means.

  According to such a configuration, when the cartridge holder 14 is moved in the insertion direction A by manually inserting the cartridge 20 into the cartridge holder 14, the arm housing 40 rotates clockwise around the rotation shaft 401. Rotate. As a result, since the gear cam 38 rotates around its central axis, the mode gear 32 engaged with the gear cam 38 also rotates around its central axis. This is a manual loading operation.

  On the other hand, as described above, the mode gear 32 and the mode motor 30 are connected via the seven reduction gears 31. Therefore, when the mode motor 30 is rotated in a predetermined direction, the mode gear 32 rotates in a predetermined direction. As a result, the gear cam 38 meshed with the mode gear 32 also rotates in a predetermined direction. As a result, the arm housing 40 having the engagement pin 403a engaged with the cam groove of the gear cam 38 rotates around the rotation shaft 401 in the clockwise direction. Accordingly, when the cartridge holder 14 moves in the insertion direction A, the cartridge 20 engaged with the cartridge holding mechanism 15 also moves in the insertion direction A. This is an automatic loading operation.

  Switching between the manual loading operation and the automatic loading operation is performed by turning on / off the first switch SW1.

  Next, with reference to FIG. 3 and FIG. 4, guide means for guiding the cartridge holder 14 and the cartridge holding mechanism 15 will be described.

  The tape drive 10 includes a first guide wall 46 and a second guide wall 47 extending in the insertion direction A as guide means. Since the first guide wall 46 is arranged on the right side in the insertion direction A, it is called a right guide wall. Since the second guide wall 47 is arranged on the left side in the insertion direction A, it is called a left guide wall.

  As shown in FIG. 3, the first guide wall (right side guide wall) 46 includes a first guide groove hole 461 for guiding the cartridge holder 14 and a second guide wall for guiding the cartridge holding mechanism 15. And a guide groove 462. The first guide groove 461 extends along the insertion direction A. On the other hand, the second guide groove hole 462 has an L-shape that extends along the insertion direction A and extends in a direction perpendicular to the insertion direction A and toward the chassis 12. A first guide pin 141 protruding from the right side wall of the cartridge holder 14 to the side is engaged with the first guide groove hole 461. A second guide pin 152 protruding from the right side wall of the cartridge holding mechanism 15 to the side is engaged with the second guide groove hole 462.

  As shown in FIG. 4, the second guide wall (left guide wall) 47 includes a pair of third guide grooves 473 for guiding the cartridge holder 14 and a pair for guiding the cartridge holding mechanism 15. 4th guide groove hole 474. The pair of third guide groove holes 473 extend along the insertion direction A. On the other hand, the pair of fourth guide groove holes 474 has an L shape extending in the insertion direction A and extending in a direction perpendicular to the insertion direction A toward the chassis 12. A pair of third guide pins 143 projecting sideways from the left side wall of the cartridge holder 14 are engaged with the pair of third guide grooves 473, respectively. A pair of fourth guide pins 154 projecting sideways from the left side wall of the cartridge holding mechanism 15 are engaged with the pair of fourth guide groove holes 474, respectively.

  Next, a head actuator 17 according to an embodiment of the present invention will be described with reference to FIGS. 5 to 10 in addition to FIG. The illustrated head actuator 17 is a composite linear actuator. As described above, the composite linear actuator 17 is obtained by combining the electromagnetic linear actuator 50 with the mechanical linear actuator.

  FIG. 5 is a perspective view showing the appearance of the electromagnetic linear actuator 50 in the composite linear actuator. FIG. 6 is a perspective view of the composite linear actuator 17, and FIG. 7 is an exploded perspective view of the composite linear actuator 17. FIG. 8 is a perspective view showing a head mounting structure according to an embodiment of the present invention, and FIG. 9 is an exploded perspective view thereof. FIG. 10 is a cross-sectional view of the head holding portion.

  As shown in FIGS. 3, 6, and 7, the head actuator 17 includes a threaded lead screw (threaded shaft) 171 having a rotation center axis extending in the vertical direction (axial direction) Z as a rotating portion. And a head lift body 172 that moves up and down along the rotation center axis as the lead screw 171 rotates as a linearly moving portion. The lead screw 171 has a lead screw gear (not shown) that rotates the lead screw 171 around the rotation center axis by another driving means (for example, a stepping motor) on the lower end side thereof. An electromagnetic linear actuator 50 described later is attached to the head lift body 172. The head lift body 172 and the magnetic circuit 70 constitute a sub-fixing portion of the electromagnetic linear actuator 50.

  The composite linear actuator 17 includes a mechanical linear actuator. The mechanical linear actuator includes a main movable part. The main movable portion includes the head lift body 172 and the electromagnetic linear actuator 50. Anyway, the combination of the lead screw 171 and the main movable part constitutes a mechanical linear actuator.

  The main movable part of the mechanical linear actuator (sub-fixing part of the electromagnetic linear actuator) will be described with reference to FIGS. As shown in FIGS. 6 and 7, 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-back direction, and the Z-axis direction is the up-down direction (axial direction).

  As described above, the main movable portion of the mechanical linear actuator has the sub-fixing portion of the electromagnetic linear actuator including the head lift body 172 and the electromagnetic linear actuator 50. The illustrated electromagnetic linear actuator 50 is a “moving coil type” electromagnetic linear actuator.

  The head lift body 172 has a substantially quadrangular prism shape, and a magnetic circuit 70 to be described later is fixed to the inner peripheral wall thereof.

  The main movable part of the mechanical linear actuator (sub-fixing part of the electromagnetic linear actuator) includes a preload bush 174 for preventing backlash of the head actuator 17 and a preload spring 175 for applying preload to the preload bush 174. It has further. The preload spring 175 is a compression coil spring. In the illustrated example, the pressurizing bush 174 is attached to the right outer wall of the head lift body 172.

  The head lift body 172 includes a front wall 1721, a rear wall 1722, a left side wall 1723, and a right side wall 1724. The pressurizing bush 174 is fixedly attached to the outer surface of the right side wall 1724. Therefore, the magnetic circuit 70 of the electromagnetic linear actuator 50 is disposed inside the four walls 1721 to 1724 of the head lift body 172.

  The preload bush 174 has a screw hole 174a in which a female screw into which the thread of the lead screw 171 is screwed is cut. The preload spring 175 is placed in a compressed state between the preload bush 174 and the base 181. Anyway, the combination of the preload bush 174 and the preload spring 175 serves as a backlash prevention mechanism for preventing the head actuator 17 from backlash.

  The lead screw 171 extends upward from its upper surface on the right side of the base 181. The lead screw 171 passes through the base 181 in the order of the preload spring 175 and the preload bush 174. An upper frame 182 is disposed at the upper end of the lead screw 171 in parallel with the base 181.

  The left side wall 1723 of the head lift body 172 has a pair of annular protrusions 1723a and 1723a protruding leftward. A pair of metal bearings 176 and 176 are disposed in the holes of the pair of annular protrusions 1723a and 1723a. The guide shaft 183 is supported by a pair of metal bearings 176 and 176. Accordingly, the head lift body 172 is slidable in the vertical direction (axial direction) Z with respect to the guide shaft 183. The guide shaft 183 extends upward from the upper surface on the left side of the base 181.

  The rear wall 1722 of the head lift body 172 has a substantially U-shaped guide portion (not shown) extending rearward. A guide bar 184 passes through the guide portion. Accordingly, the head lift body 172 can slide in the vertical direction (axial direction) Z, and the head lift body 172 can be prevented from rotating. The guide bar 184 extends upward from the upper surface on the rear side of the base 181.

  Three support columns 185 extend upward from the upper surface of the base 181. On the upper surface of these three support pillars 185, the upper frame 182 is fixed with three screws 186.

  The upper frame 182 has a first insertion hole 182a through which the upper end 183a of the guide shaft 183 is inserted, and a second insertion hole 182b through which the upper end 184a of the guide bar 184 is inserted.

  The electromagnetic linear actuator 50 will be described with reference to FIG. 5 in addition to FIGS. 6 and 7.

  The illustrated electromagnetic linear actuator 50 is for moving the magnetic head 17a as the object to be lifted up and down along the vertical direction Z. The magnetic head 17a extends in the vertical direction (vertical direction) Z. The magnetic head 17a is held by a head holding plate 17b. The magnetic head 17a and the head holder 17b constitute a head assembly. As will be described later, the head holding plate 17b is attached to the head holding portion 63A by an adhesive.

  The magnetic head 17a is electrically connected to an external circuit (not shown) through a flexible printed circuit (FPC) (not shown). An MR (magnetro-resistive) head is used as the magnetic head 17a. The MR head is a device that is very sensitive to static electricity and weak in static electricity resistance. Therefore, care must be taken when handling the MR head.

  The electromagnetic linear actuator 50 includes a sub-fixed portion (172, 70), a sub-movable portion 60 that holds the head assembly up and down along the vertical direction Z with respect to the sub-fixed portion (172, 70), It has a shaft support mechanism 80 that supports the sub movable part 60 with respect to the fixed part 70 so as to be linearly movable along the vertical direction Z. The sub-fixing part (172, 70) is composed of the head lift body 172 and the magnetic circuit 70 as described above.

  The magnetic circuit 70 includes a bottomed rectangular cylindrical outer yoke 71, a magnet 72 fixed to the inner peripheral surface of the outer yoke 71, and a cylindrical inner yoke (center yoke) 74.

  The illustrated outer yoke 71 has a bottomed rectangular tube shape formed by pressing. More specifically, the outer yoke 71 has a square plate-shaped bottom yoke (not shown) and four rectangular plate-shaped side wall yokes 712 extending upward from the edges of the four sides of the bottom yoke. On the other hand, the magnet 72 includes four flat magnet pieces 721 attached to the inner walls of the four side wall yokes 712 respectively. The inner surface of each magnet piece 721 has the same polarity. That is, for example, if the outer surface of each magnet piece 721 is an N pole, the inner surface is an S pole. Concentric with the outer yoke 71, a cylindrical inner yoke (center yoke) 74 is erected from the center of the bottom yoke 711.

  In the illustrated outer yoke 71, the bottom yoke is made of a stamped steel plate, and each of the four side wall yokes 712 is also made of a stamped steel plate. The bottom yoke and the four side wall yokes 712 are bonded together in a box shape using an adhesive such as a UV adhesive to form an outer yoke 71. The four magnet pieces 721 are fixed to the inner walls of the corresponding four side wall yokes 712 by bonding.

  On the other hand, the sub movable portion 60 includes a coil 61 wound around the axial direction Z, and a coil support portion 62 (FIG. 1) that supports the coil 61 at its upper end. The coil 61 is disposed in the gap between the magnet 72 and the cylindrical inner yoke 74. Thrust force acts on the coil 61 in the longitudinal direction (axial direction) Z according to Fleming's left-hand rule by passing an electric current therethrough.

  The bottom yoke of the outer yoke 71 has a yoke through hole (not shown) through which the shaft 81 of the shaft support mechanism 80 passes. The inner yoke 74 has an insertion hole 74 a for inserting the shaft 81 of the shaft support mechanism 80.

  The shaft support mechanism 80 is for supporting the sub movable portion 60 along the vertical direction Z so as to be linearly movable with respect to the sub fixed portion. The shaft support mechanism 80 extends in the axial direction Z, and passes through the insertion hole 74a of the cylindrical inner yoke 74 and the yoke through hole of the bottom yoke. And a bearing (not shown) fixed by caulking to the bottom yoke.

  On the other hand, the sub movable portion 60 includes a coil 61, a coil support portion 62 that supports the coil 61 at its upper end, and a head holding portion 63A that holds the head 17a via the head holding plate 17b. As will be described later, the head holding plate 17b is joined to the head holding portion 63A by an adhesive. The head holding portion 63 </ b> A is provided in front of the front wall 1721 of the head lift body 172.

  The coil support part 62 includes an annular coil holding part 621 that holds the coil 61, a bridge part 622 that extends in the front-rear direction Y inside the coil holding part 621, and a front part extending from the coil holding part 621. And a first arm portion 623 coupled to the upper end of the head holding portion 63A. The bridge portion 622 has a first through hole 622a for allowing the upper end portion of the shaft 81 to pass through at the center thereof. The head holding portion 63A has a second arm portion 632 extending rearward from the lower end thereof. A second through hole for penetrating the lower end portion of the shaft 81 is formed in the center portion of the second arm portion 632.

  Male screws (not shown) are cut at the upper and lower ends of the shaft 81. The upper end portion of the shaft 81 passes through the first through hole 622a of the bridge portion 622 of the coil support portion 62, and a first nut 83 is screwed as will be described later, whereby the upper end portion of the shaft 81 is It is fixed to the coil support part 62. On the other hand, the lower end portion of the shaft 81 passes through the second through hole of the second arm portion 632 of the head holding portion 63 </ b> A and a second nut (not shown) is screwed into the lower end portion of the shaft 81. The part is attached to the head holding part 73A.

  A leaf spring 85 is interposed between the first nut 83 and the shaft 81. Both ends of the leaf spring 85 are attached to the left side wall 1723 and the right side wall 1724 of the head lift body 172.

  In this way, the sub movable part 60 is pivotally supported by the bearing through the shaft 81 fixed to the sub movable part 60.

  Anyway, by supporting the sub movable portion 60 with respect to the magnetic circuit 70 by the shaft support mechanism 80 so as to be movable up and down, the sub movable portion 60 of the electromagnetic linear actuator 50 can be easily moved linearly.

  Next, a head mounting structure (a method of mounting the magnetic head 17a to the sub movable portion 60) according to an embodiment of the present invention will be described with reference to FIGS. FIG. 8 is a perspective view showing a state in which the magnetic head 17a is attached to the head holding portion 63A of the sub movable portion 60, and FIG. 9 is an exploded perspective view thereof. FIG. 10 is a cross-sectional view of the head holding portion 63A.

  As shown in FIGS. 8 and 9, 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-back direction, and the Z-axis direction is the up-down direction (axial direction).

  The magnetic head 17a extends in the vertical direction (vertical direction) Z. The magnetic head 17a is held by a head holding plate 17b. The magnetic head 17a and the head holding plate 17b constitute a head assembly. As will be described later, the head holding plate 17b is joined to the head holding portion 63A of the sub movable portion 60 by an adhesive.

  More specifically, the head holding portion 63A has a head attachment portion 631A for attaching the head assembly (17a, 17b) to the front thereof. The head attachment portion 631A has three head attachment surfaces 631b that protrude forward at a total of three locations, one at the upper end and two at the lower end. With these three head mounting surfaces 631b, the magnetic head 17a is fixed by an adhesive via the head holding plate 17b.

  In the present embodiment, of the three head mounting surfaces 631b, one is provided at the upper end of the head mounting portion 631 and the remaining two are provided at the lower end of the head mounting portion 631, but the reverse is also possible. That is, one of the three head mounting surfaces may be provided at the lower end portion of the head mounting portion 631 and the remaining two may be provided at the upper end portion of the head mounting portion 631.

  The head attachment portion 631A has a pair of protrusions 633 that are spaced apart from each other in the vertical direction Z and protrude forward. On the other hand, the head holding plate 17b has a pair of through holes 17b-1 (FIG. 7) into which the pair of protrusions 633 are inserted. As a result, the head assembly (17a, 17b) is positioned in the Z-axis direction (vertical direction). That is, the combination of the pair of protrusions 633 and the pair of through holes 17b-1 serves as a vertical positioning means for determining the position in the Z-axis direction (vertical direction) in the head assembly (17a, 17b).

  In the conventional head mounting portion 631, as shown in FIG. 2, it is necessary to increase the processing accuracy of the entire head mounting surface 631a provided on the entire front surface thereof. On the other hand, in the head mounting portion 631A according to the present embodiment, as shown in FIG. 9, it is only necessary to increase the processing accuracy of only the three head mounting surfaces 631b. A structure is employed in which the head 17a is fixed using an adhesive via a head holding plate 17b.

  By adopting such a head mounting structure, the processing portion (processing area) on the head mounting surface can be reduced, so that the head holding portion 63A can be manufactured at low cost. Further, since the magnetic head 17a is held at three locations, it is possible to provide a small electromagnetic linear actuator 50 with improved mounting accuracy of the head assembly (17a, 17b).

  Furthermore, the accuracy of the head mounting portion 631A can be ensured by performing the above processing. For example, in the case of the conventional head holding portion 63, the processing accuracy with a vertical degree of 0.1 mm is the limit in processing the parts. On the other hand, in the case of the head holding portion 63A according to the present embodiment, since there are few parts to be machined, machining with a perpendicularity of 0.05 mm is possible and can be manufactured at low cost.

  The head holding portion 63A may be manufactured by cutting as described above after casting or forging, or a molded product by injection molding using a mold using a resin material such as liquid crystal polymer (LCP). You may manufacture as. When the head holding portion 63A is manufactured by injection molding, the dimensional accuracy can be improved by adjusting only the three head mounting surfaces 631b with the mold. In other words, a mold having a cavity corresponding to the head holding portion 63A including the head mounting portion 631A having the three head mounting surfaces 631b may be used. Anyway, the head holding portion 63A may be made of a non-magnetic material.

  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 head mounting surfaces 631b are provided at three locations of the head mounting portion 631A, but the number of head mounting surfaces 631b may be two or four or more. In the embodiment described above, the head mounting structure for fixing the head assembly to the head mounting portion using an adhesive has been described as an example. However, the head assembly is screwed to the head mounting portion using a plurality of screws. It can also be applied to a head mounting structure for fastening. Further, 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 similarly applied to an electromagnetic linear actuator. In the above-described embodiment, only the example of the “movable coil type” electromagnetic linear actuator has been described. However, the present invention can be similarly applied to the “movable magnet type” electromagnetic linear actuator. it is obvious.

It is a perspective view which shows the conventional head mounting structure. It is a disassembled perspective view of the head mounting structure shown in FIG. It is a perspective view which shows the tape drive which is a recording / reproducing apparatus with which this invention is applied in the state which removed the upper cover. FIG. 4 is a perspective view of the tape drive shown in FIG. 3 viewed from the lower surface side. It is a perspective view which shows the external appearance of the electromagnetic linear actuator which concerns on one embodiment of this invention used for the tape drive of FIG. FIG. 6 is a perspective view of a composite linear actuator including the electromagnetic linear actuator shown in FIG. 5 used in the tape drive of FIG. 1. FIG. 7 is an exploded perspective view of the composite linear actuator shown in FIG. 6. It is a perspective view which shows the head attachment structure which concerns on one embodiment of this invention. FIG. 9 is an exploded perspective view of the head mounting structure shown in FIG. 8. It is sectional drawing of the head holding | maintenance part used for the head attachment structure shown in FIG.

Explanation of symbols

10 Recording / playback device (tape drive)
DESCRIPTION OF SYMBOLS 17 Head actuator 17a Magnetic head 17b Head holding plate 17b-1 Through hole 171 Lead screw 172 Head lift body 50 Electromagnetic linear actuator 60 Sub movable part 61 Coil 62 Coil support part 63A Head holding part 631A Head mounting part 631b Head mounting surface 633 Projection 70 Magnetic circuit 80 Shaft support mechanism

Claims (17)

In an electromagnetic linear actuator comprising a fixed portion and a movable portion that moves linearly in the axial direction by electromagnetic force with respect to the fixed portion,
The movable part has a head holding part for holding a head assembly, the head holding part has a head attaching part for attaching the head assembly, and the head attaching part has N positions (N is 2). An electromagnetic linear actuator characterized by having N head mounting surfaces for mounting in the above integer). The axial direction is the vertical direction of the electromagnetic linear actuator,
The head assembly has a magnetic head extending in the vertical direction, and a head holding plate for holding the magnetic head,
The electromagnetic linear actuator according to claim 1, wherein the head holding plate is fixed to the N head mounting surfaces with an adhesive.   The electromagnetic linear actuator according to claim 2, wherein N is three.   4. The electromagnetic type according to claim 3, wherein one of the three head mounting surfaces is provided at an upper end portion of the head mounting portion, and the other two are provided at a lower end portion of the head mounting surface. Linear actuator.   5. The electromagnetic linear actuator according to claim 2, further comprising a vertical positioning unit that determines the vertical position of the head assembly. The vertical positioning means is
A pair of projections spaced apart from each other in the vertical direction and projecting from the head mounting portion;
The electromagnetic linear actuator according to claim 5, wherein the electromagnetic linear actuator includes a pair of through holes that are formed in the head holding plate and into which the pair of protrusions are inserted.   A head mounting structure for mounting a head assembly to a head mounting portion, wherein the head mounting portion has N head mounting surfaces for mounting the head assembly at N locations (N is an integer of 2 or more). Head mounting structure. The head assembly has a magnetic head extending in the vertical direction, and a head holding plate for holding the magnetic head,
The head mounting structure according to claim 7, wherein the head holding plate is fixed by an adhesive on the N head mounting surfaces.   The head mounting structure according to claim 8, wherein N is three.   The head mounting according to claim 9, wherein one of the three head mounting surfaces is provided at an upper end portion of the head mounting portion, and the other two are provided at a lower end portion of the head mounting surface. Construction.   11. The head mounting structure according to claim 8, further comprising vertical positioning means for determining the vertical position of the head assembly. The vertical positioning means is
A pair of projections spaced apart from each other in the vertical direction and projecting from the head mounting portion;
The head mounting structure according to claim 11, comprising a pair of through holes that are formed in the head holding plate and into which the pair of protrusions are inserted. A head mounting method for mounting a head assembly to a head mounting portion,
Forming N head attachment surfaces for attaching the head assembly to the head attachment portion at N locations (N is an integer of 2 or more);
Fixing the head assembly on the N head mounting surfaces with an adhesive. The head assembly has a magnetic head extending in the vertical direction, and a head holding plate for holding the magnetic head,
The head mounting method according to claim 13, wherein the head holding plate is fixed by the adhesive on the N head mounting surfaces.   The head mounting method according to claim 13 or 14, wherein the N is three.   The head mounting method according to claim 13, wherein the step of forming the N head mounting surfaces is performed by machining. The head mounting portion is made of a resin material,
The step of forming the N head mounting surfaces is performed by injection molding using a mold having a cavity corresponding to the head mounting portion having the N head mounting surfaces. The head mounting method according to claim 1.

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