JP2007027635A - Electromagnetic linear actuator and composite linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a composite linear actuator equipped with a magnetic circuit comprising a center yoke, excellent in dimensional accuracy without deteriorating magnetic characteristics. <P>SOLUTION: The composite linear actuator comprises the electromagnetic linear actuator (50) consisting of sub fixing units (172, 70), and a sub movable unit (60) moved linearly into the axial direction by an electromagnetic force with respect to the sub fixing units. The sub fixing units (172, 70) comprise a magnetic circuit (70) consisting of yoke members (71, 74, 75) and permanent magnets (72, 73) while the sub movable unit (60) comprises a coil. The yoke member is constituted of outer yokes (71, 75) and a center yoke (74). The center yoke (74) is constituted of laminated thin steel sheets. <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 more particularly, an electromagnetic type (composite type) that can be used as a head feeding mechanism of a magnetic head actuator assembly used therein. ) Related to linear actuators.

  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 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 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 portion 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.

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

  As described above, a recording / reproducing apparatus (tape drive) having a large storage capacity includes an electromagnetic linear actuator for fine adjustment using a VCM. In order to cope with the further increase in the storage capacity of the recording / reproducing apparatus, it is necessary to improve the characteristics of the VCM.

  As one method for improving the characteristics of the VCM, a method for increasing the flux linkage to the coil is known. One method for increasing the flux linkage to the coil is to increase the thickness of the center yoke and collect the magnetic flux on the center yoke side.

  It is assumed that the center yoke is composed of a single iron plate having a high magnetic permeability μ. In this case, when the thickness of the iron plate is increased, there is a problem that the iron plate cannot be removed by pressing. Further, even if the iron plate is pulled out by the press, there is a problem that the dimensional accuracy of the center yoke is deteriorated due to the sag of the press.

  On the other hand, it is assumed that the center yoke is manufactured by sintering, MIM (metal injection molding) or the like. In this case, the sintered yoke and the MIM yoke have a problem that the magnetic properties of the center yoke are deteriorated because the magnetic permeability μ is low. Further, the sintered yoke and the MIM yoke have a problem that the cost of the center yoke is increased.

  Further, it is necessary to assemble the magnetic circuit of the electromagnetic linear actuator so that the sub-fixing portion (particularly the magnetic circuit) of the electromagnetic linear actuator is not disassembled even when an impact or the like is applied to the recording / reproducing apparatus. When assembling the magnetic circuit, the outer yoke and the center yoke may be fixed with screws in order to allow reassembly. In this case, if the center yoke is formed of a single iron plate, there is a problem that it becomes difficult to perform tapping on the center yoke due to the sag of the press. Moreover, since the secondary processing such as tapping must be performed on the center yoke, there is a problem that the cost of the magnetic circuit increases.

  An object of the present invention is to provide an electromagnetic linear actuator (composite linear actuator) provided with a magnetic circuit including a center yoke with good dimensional accuracy without deteriorating magnetic characteristics.

  Another object of the present invention is to provide an electromagnetic linear actuator (composite linear actuator) having a magnetic circuit that can be reassembled without the need for screwing.

  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), wherein the fixed portion has a magnetic circuit (70) including a yoke member (71, 74, 75) and a permanent magnet (72, 73), the movable portion includes a coil, and the yoke The electromagnetic linear actuator, wherein the member is composed of an outer yoke (71, 75) and a center yoke (74), wherein the center yoke (74) is composed of a laminated steel plate. An actuator is obtained.

  In the electromagnetic linear actuator of the present invention, the axial direction may be the vertical direction (Z) of the electromagnetic linear actuator. In this case, the outer yoke may be composed of a yoke base (71) and an upper yoke (75) provided at the upper portion of the yoke base, and the center yoke (74) is formed at the central portion of the yoke base. The permanent magnet may be formed of a pair of plate magnets (72, 73) accommodated in the yoke base. The yoke base (71) includes a bottom yoke (711), a front wall yoke (712) extending upward from a front end of the bottom yoke, and a rear wall extending upward from a rear end of the bottom yoke. A yoke (713) may be used. The front wall yoke (712) and the rear wall yoke (713) are spaced apart from each other, and one of the pair of plate magnets (72) is attached to the inner wall of the front wall yoke. The other of the pair of plate magnets (73) is attached to the inner wall of the rear wall yoke, and the bottom yoke (711) is interposed between the front wall yoke (712) and the rear wall yoke (713). The center yoke (74) may be erected from the center of the center. The center yoke (74) may be composed of a central portion (741) and a pair of side portions (742) on both the left and right sides of the central portion. In this case, the pair of side portions (742) includes a pair of upper protrusions (742a) protruding upward from the upper end of the central portion and a pair of lower protrusions protruding downward from the lower end of the central portion. Part (742b), the bottom yoke (711) has a pair of notches (711a) into which the pair of lower protrusions are inserted, and the upper yoke (75) It is preferable to have a pair of notches (75a) into which the pair of upper protrusions are inserted.

  In the electromagnetic linear actuator of the present invention, the fixed portion may include a head lift body (172) to which the magnetic circuit (70) is fixed in front. In this case, it is preferable that the head lift body (172) has a pair of yoke pressers (1726) which are provided so as to protrude forward from the upper end of the head lift body and press the two corners at the rear of the upper yoke. The pair of yoke retainers (1726) preferably have a recess (1726a) having a shape corresponding to the shape of the two corners behind the upper yoke. The laminated steel plate (74) may be constituted by laminating first to Nth (N is an integer of 6 or more) steel plates (74-1 to 74-6) in this order. In this case, each of the first to (N-1) -th steel plates (74-1 to 74-5) includes four concave portions and convex portions (742c) at the ends in the vertical direction of the pair of side portions. The N-th steel plate (74-6) has four recesses (743d) at the ends in the vertical direction of the pair of side portions, and the protrusions are formed in the recesses. It is desirable to be configured to be inserted. The movable portion (60) may be supported by the upper leaf spring (81) and the lower leaf spring (82) so as to be linearly movable with respect to the fixed portion.

  According to the second aspect of the present invention, a lead screw (171) having a rotation center axis extending in the axial direction (Z), and a main movable portion (moving linearly in the axial direction by rotation of the lead screw) 172, 50), and the main movable part is a secondary fixed part (172, 70) and a secondary movable part that linearly moves in the axial direction with respect to the secondary fixed part by electromagnetic force. The secondary linear actuator (172, 70) includes a yoke member (71, 74, 75) and a permanent magnet (72, 70). 73), the sub movable portion (60) includes a coil, and the yoke member includes an outer yoke (71, 75) and a center yoke (74). In the composite linear actuator, characterized in that the center yoke (74) is composed of laminated steel sheets, composite linear actuator is obtained.

  In the composite linear actuator of the present invention, the axial direction may be the vertical direction (Z) of the composite linear actuator. In this case, the outer yoke may be composed of a yoke base (71) and an upper yoke (75) provided on the yoke base, and the center yoke (74) is a central portion of the yoke base. The permanent magnet may be composed of a pair of plate magnets (72, 73) accommodated in the yoke base. The yoke base (71) includes a bottom yoke (711), a front wall yoke (712) extending upward from a front end of the bottom yoke, and a rear wall extending upward from a rear end of the bottom yoke. A yoke (713) may be included, and the front wall yoke (712) and the rear wall yoke (713) may be spaced apart from each other. One of the pair of plate magnets (72) is attached to the inner wall of the front wall yoke (712), and the other of the pair of plate magnets (73) is attached to the inner wall of the rear wall yoke (713). It ’s good. The center yoke (74) may be erected from the center of the bottom yoke (711) between the front wall yoke (712) and the rear wall yoke (713). The center yoke (74) may be composed of a central portion (741) and a pair of side portions (742) on both the left and right sides of the central portion. In this case, the pair of side portions includes a pair of upper projecting portions (742a) projecting upward from the upper end of the central portion and a pair of lower projecting portions (742b) projecting downward from the lower end of the central portion. The bottom yoke (711) has a pair of notches (711a) into which the pair of lower protrusions are inserted, and the upper yoke (75) It is preferable to have a pair of notches (75a) into which the protrusions are inserted.

  In the composite linear actuator of the present invention, the sub-fixing portion may include a head lift body (172) in which the lead screw (171) passes and the magnetic circuit is fixed in front. In this case, it is desirable that the head lift body (172) has a pair of yoke pressers (1726) which are provided so as to protrude forward from the upper end of the head lift body and press the two corners at the rear of the upper yoke. The pair of yoke retainers (1726) preferably has a recess (1726a) having a shape corresponding to the shape of two corners at the rear of the upper yoke. In addition, the laminated steel plate (74) may be configured by laminating first to Nth (N is an integer of 6 or more) steel plates (74-1 to 74-6) in this order. In this case, each of the first to (N-1) -th steel plates (74-1 to 74-5) includes four concave portions and convex portions (742c) at the ends in the vertical direction of the pair of side portions. The N-th steel plate (74-6) is formed with four concave portions (742d) at the ends in the vertical direction of the pair of side portions, and the convex portions are formed in the concave portions. It is desirable to be configured to be inserted. The sub movable portion may be supported by the upper plate spring (81) and the lower plate spring (82) so as to be linearly movable with respect to the sub fixed portion.

  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 center yoke is composed of laminated steel plates, there is an effect that the dimensional accuracy of the center yoke is improved without deteriorating the magnetic characteristics.

  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. 1 is a perspective view of the tape drive 10 with the upper lid removed as viewed from the upper surface side. FIG. 2 is a perspective view of the tape drive 10 shown in FIG.

  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 through seven reduction gears 31 (only three reduction gears are shown in FIG. 1). 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. 1, 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. 2, 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. 1, 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. 1 and FIG. 2, the 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. 1, the first guide wall (right side guide wall) 46 has 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. 2, 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. 3 to 12 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. 3 is a perspective view showing the external appearance of the electromagnetic linear actuator 50 in the composite linear actuator, and FIG. 4 is an exploded perspective view of the electromagnetic linear actuator 50.

  5 to 8 are diagrams showing the magnetic circuit 70 of the electromagnetic linear actuator 50. FIG. 5 is a perspective view of the magnetic circuit 70 as viewed from the upper surface side, and FIG. 6 is an exploded perspective view of the magnetic circuit 70 shown in FIG. 7 is a perspective view of the magnetic circuit 70 as viewed from the bottom surface (lower surface) side, and FIG. 8 is an exploded perspective view of the magnetic circuit 70 shown in FIG.

  On the other hand, FIGS. 9 to 12 are diagrams showing the composite linear actuator 17 in which the sub movable portion 60 in the electromagnetic linear actuator 50 is omitted. FIG. 9 is a perspective view of the composite linear actuator 17, and FIG. 10 is an exploded perspective view of the composite linear actuator 17. FIG. 11 is a plan view of the composite linear actuator 17, and FIG. 12 is a front view of the composite linear actuator 17.

  As shown in FIGS. 1 and 9 to 12, the head actuator 17 includes a threaded lead screw (threaded shaft) 171 having a rotation center axis extending in the vertical direction (axial direction) as a rotating portion. The head lift body 172 that moves up and down along the rotation center axis as the lead screw 171 rotates as a linearly moving part. A lead screw gear 173 that rotates the lead screw 171 around the rotation center axis by other driving means (for example, a stepping motor) is attached to the lower end side of the lead screw 171. 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 detailed configuration of the main movable portion of the mechanical linear actuator (sub-fixing portion of the electromagnetic linear actuator) will be described later with reference to FIGS.

  The electromagnetic linear actuator 50 will be described with reference to FIGS. As shown in FIGS. 3 and 4, 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 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 holder 17b. The magnetic head 17a and the head holder 17b constitute a head assembly. The head holder 17b is attached to the sub movable part 60 described later by two screws 17c.

  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), An upper leaf spring 81 and a lower leaf spring 82 that support the sub movable portion 60 so as to be linearly movable with respect to the fixed portion 70 are provided.

  The sub-fixed portion includes a magnetic circuit 70 including a yoke base 71, a pair of plate magnets 72 and 73 accommodated in the yoke base 71, a center yoke 74, and an upper yoke 75. The yoke base 71 has a U-shaped cross section, and includes a bottom yoke 711, a front wall yoke 712 extending upward from the front end of the bottom yoke 711, and extending upward from the rear end of the bottom yoke 711. And a rear wall yoke 713. That is, the front wall yoke 712 and the rear wall yoke 713 are disposed to face each other while being separated from each other. One magnet 72 is attached to the inner wall of the front wall yoke 712, and the other magnet 73 is attached to the inner wall of the rear wall yoke 713. A center yoke 74 is erected from the center of the bottom yoke 711 between the front wall yoke 712 and the rear wall yoke 713.

  More specifically, the center yoke 74 includes a central portion 741 and a pair of side portions 742 on both the left and right sides of the central portion 741. The height of the pair of side portions 742 is longer than the length (height) of the central portion 741 in the vertical direction. In other words, the pair of side portions 742 includes a pair of upper protruding portions 742 a that protrude upward from the upper end of the central portion 741 and a pair of lower protruding portions 742 b that protrude downward from the lower end of the central portion 741. And have.

  As shown in FIGS. 4 to 8, the center yoke 74 is composed of a laminated steel plate in which a plurality of iron plates are laminated. In the illustrated example, the center yoke 74 is made of a laminated steel plate in which six iron plates are laminated. The number of laminated steel plates is preferably 6 or more. The thickness of each laminated iron plate is the same, but is preferably in the range of 0.2 mm to 0.6 mm. The detailed configuration of the center yoke 74 will be described later with reference to the drawings.

  The bottom yoke 711 has a pair of notches 711a into which the pair of lower protrusions 742b of the center yoke 74 are inserted. Similarly, the upper yoke 75 has a pair of notches 75a into which the pair of upper protrusions 742a of the center yoke 74 are inserted. The upper yoke 75 covers the yoke base 71 and the center yoke 74 at the top.

  The upper yoke 75 has a spring mounting portion 75b in which a screw hole is cut for mounting the central portion of the upper leaf spring 81 at the central portion. The bottom yoke 711 also has a spring mounting portion 711b with a threaded hole for mounting the central portion of the lower leaf spring 82 at the central portion thereof.

  The rear wall yoke 713 has a pair of screw holes 713a for fixing the auxiliary fixing portion 70 to a head lift body 172 described later.

  On the other hand, the sub movable portion 60 includes a carriage 61 that moves in the vertical direction while holding the head assembly (magnetic head 17 a), and a coil (not shown) that is accommodated in the carriage 61. The coil is an air-core coil and is wound around the center yoke 74 at a distance.

  More specifically, the carriage 61 is disposed in front of the front wall yoke 712, and includes a front frame 611 to which the head holder 17b of the head assembly is attached, and a right frame 612 extending rearward from the right end of the front frame 611. A left frame 613 extending rearward from the left end of the front frame 611, a lower bridge (not shown) that bridges the right frame 612 and the left frame 613 at the lower end, a right frame 612 and a left frame 613 And an upper bridge portion 615 that bridges between the two at the upper end.

  A coil (not shown) is mounted on the lower bridge. In other words, the coil is accommodated in a space surrounded by the lower bridge portion, the upper bridge portion 615, the right frame 612, and the left frame 613.

  The right frame 612 has a spring mounting portion 612a with a screw hole for attaching the right end portion of the upper leaf spring 81 at the center of the upper end portion thereof, and the right end of the upper leaf spring 81 at both front and rear ends of the upper end portion. It has a pair of bosses 612b for positioning the part. Similarly, the left frame 613 has a spring mounting portion 613a with a screw hole for attaching the left end portion of the upper leaf spring 81 at the center of the upper end portion, and upper leaf springs at both front and rear ends of the upper end portion. A pair of bosses 613b for positioning the left end portion of 81 are provided.

  Similarly, the right frame 612 has a spring mounting portion (not shown) with a threaded hole for mounting the right end portion of the lower leaf spring 82 at the center of the lower end portion thereof, at both front and rear ends of the lower end portion. And a pair of bosses (not shown) for positioning the right end of the lower leaf spring 82. Similarly, the left frame 613 has a spring mounting portion (not shown) with a screw hole for attaching the left end portion of the lower leaf spring 82 at the center of the lower end portion thereof, and is provided at both front and rear ends of the lower end portion. And a pair of bosses (not shown) for positioning the left end portion of the lower leaf spring 82.

  The upper leaf spring 81 has a central through hole 811 for penetrating the first screw 91 at the center, and a right through hole 812 for penetrating the second screw 92 at the center of the right end. And a left through hole 813 for penetrating the third screw 93 at the center of the left end. Further, the upper leaf spring 81 has a pair of right positioning holes 814 into which a pair of bosses 612b provided at the upper end portion of the right frame 612 are fitted at both front and rear ends of the right end portion. At both ends, there is a pair of left positioning holes 815 into which a pair of bosses 613b provided at the upper end of the left frame 613 are fitted.

  The upper leaf spring 81 has a pair of bent portions 816 protruding upward between the central through hole 811 and the right through hole 812 and between the central through hole 811 and the left through hole 813. That is, the upper leaf spring 81 has a pair of bent portions 816 symmetrically about the central portion between the central portion and both end portions. The upper leaf spring 81 has a pair of openings 817 between the bent portion 816 and the right side through hole 812 and between the bent portion 816 and the left side through hole 813, and the central through hole 811 and the bent portions on both sides thereof. A pair of openings 818 is provided between the two terminals 816.

  The upper leaf spring 81 having such a configuration is attached to the upper yoke 75 by the first screw 91 through the central through hole 811 and the right end of the upper leaf spring 81 through the right through hole 812. 92 is attached to the upper end portion of the right frame 612, and the left end portion is attached to the upper end portion of the left frame 613 by the third screw 93 through the left through hole 813.

  At any rate, the upper leaf spring 81 is attached to the magnetic circuit 70 at the central portion and is attached to the auxiliary movable portion 60 at both ends, and has a symmetrical shape with the central portion as the center.

  Similarly, the lower leaf spring 82 has a central through hole 821 for penetrating the fourth screw 94 at the center thereof, and a right side penetrating for penetrating the fifth screw 95 at the center of the right end portion thereof. It has a hole 822 and a left-side through hole 823 for penetrating the sixth screw 96 at the center of its left end. The upper leaf spring 82 has a pair of right positioning holes 824 fitted to a pair of bosses provided at the lower end of the right frame 612 at both front and rear ends of the right end, and both front and rear ends of the left end. And a pair of left positioning holes 825 into which a pair of bosses provided at the lower end of the left frame 613 are fitted.

  The lower leaf spring 82 has a pair of bent portions 826 that protrude downward between the central through hole 821 and the right through hole 822 and between the central through hole 821 and the left through hole 823. That is, the lower leaf spring 82 has a pair of bent portions 826 symmetrically about the center portion between the center portion and both end portions. Further, the lower leaf spring 82 has a pair of openings 827 between the bent portion 826 and the right side through hole 822 and between the bent portion 826 and the left side through hole 823, and the central through hole 821 and the bent portions on both sides thereof. A pair of openings 828 is provided between the two openings 826.

  The lower leaf spring 82 having such a configuration is attached to the bottom yoke 711 by the fourth screw 94 through the central through hole 821 at the center, and the fifth screw through the right through hole 822 at the right end. 95 is attached to the lower end portion of the right frame 612, and the left end portion is attached to the lower end portion of the left frame 613 by the sixth screw 96 through the left through hole 823.

  In any case, the lower leaf spring 82 has a symmetrical shape around the central portion, which is attached to the sub-fixing portion 70 at the center and attached to the sub-movable portion 60 at both ends.

  As described above, since the pair of bent portions 816 and 826 are added to each of the upper leaf spring 81 and the lower leaf spring 82, when the auxiliary movable portion 60 of the electromagnetic linear actuator 50 is moved, It becomes easy to move. The reason is that the pair of bent portions 816 and 826 increases the degree of freedom in the left-right direction (X-axis direction), so that the spring pressure of each of the upper leaf spring 81 and the lower leaf spring 82 decreases.

  At any rate, by supporting the sub movable portion 60 with respect to the magnetic circuit 70 by the upper leaf spring 81 and the lower leaf spring 82 so as to be movable up and down, it is easy to move the sub movable portion 60 of the electromagnetic linear actuator 50 linearly. Can be done.

  Next, the main movable part of the mechanical linear actuator will be described with reference to FIGS.

  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. 9 to 12, only the sub-fixed portion in the electromagnetic linear actuator 50 is shown.

  The head lift body 172 has a pair of through holes 172 a that penetrate the pair of screws 97 at positions corresponding to the pair of screw holes 713 a of the rear wall yoke 713 of the magnetic circuit 70. The magnetic circuit 70 is fixed to the head lift body 172 by screwing the pair of screws 97 into the pair of screw holes 713a of the rear wall yoke 713 through the pair of through holes 172a.

  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.

  The head lift body 172 includes a bottom surface portion 1721, a ceiling portion 1722, and a central support portion 1723 that supports the bottom surface portion 1721 and the ceiling portion 1722. The center support portion 1723 is formed with the above-described pair of through holes 172a. Therefore, the magnetic circuit 70 of the electromagnetic linear actuator 50 is disposed in front of the center support portion 1723 of the head lift body 172. The bottom surface portion 1721 and the ceiling portion 1722 have through holes 1721a and 1722a for penetrating the lead screw 171 respectively. In the head lift body 172, the preload bush 174 is disposed between the bottom surface portion 1721 and the ceiling portion 1722. Between the preload bush 174 and the bottom surface portion 1721, the preload spring 175 is placed in a compressed state. 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 passes through the head lift body 172 from the bottom side in the order of the through hole 1721a of the bottom surface portion 1721, the preload spring 174, the preload bush 173, and the through hole 1722a of the ceiling portion 1722.

  The head lift body 172 further includes a right support portion 1724 fixed to the right side of the center support portion 1723. The right support portion 1724 has a pair of annular projecting portions 1724a and 1724a projecting forward from the upper and lower ends thereof. A pair of metal bearings 176 and 176 are disposed in the holes of the pair of annular protrusions 1724a and 1724a. A guide shaft (not shown) 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.

  The head lift body 172 further includes an extending portion 1725 extending forward from the left side of the central support portion 1723. A substantially U-shaped guide portion 1725 a is provided at the front end of the extending portion 1725. A guide bar (not shown) is inserted through the guide portion 1725a. 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.

  As described above, the upper yoke 75 in the magnetic circuit 70 has the yoke base 71 and the center yoke 74 in a state in which the upper protrusions 742a of the pair of side portions 742 of the center yoke 74 are inserted into the pair of cutout portions 75a. And is covered at the top. In other words, the upper yoke 75 is only mounted on the upper surfaces of the yoke base 71 and the center yoke 74, and the upper yoke 75 is connected to the yoke base 71 and the center by the magnetic attractive force of the pair of plate magnets 72 and 73. It is sucked by the upper surface of the yoke 74. Therefore, the upper yoke 75 may be detached from the yoke base 71 and the center yoke 74 when some impact or the like is applied to the tape drive 10.

  Therefore, in the present invention, in order to prevent the upper yoke 75 from being detached from the center yoke 74, the head lift body 172 has a pair of yoke pressers 1726 provided to project forward from the upper end thereof. That is, the pair of yoke pressers 1726 serves to press the corners at the two rear portions of the upper yoke 75 toward the rear wall yoke 713 of the base yoke 71. The pair of yoke retainers 1726 have recesses 1726 a having shapes corresponding to the shapes of the two corners behind the upper yoke 75.

  As described above, in the present embodiment, the fixing between the outer yoke (the yoke base 71 and the upper yoke 75) and the center yoke 74 is performed by inserting the lower side with the head lift body 172 which is a separate part. It is done by pressing. As a result, the magnetic circuit 70 can be reassembled without fixing the outer yoke (the yoke base 71 and the upper yoke 75) and the center yoke 74 with screws. Further, since the screwing of the center yoke 74 to the outer yoke can be eliminated, the number of processing steps and the number of parts of the composite linear actuator can be reduced. As a result, the cost of the composite linear actuator can be reduced.

  Next, the center yoke 74 used in the magnetic circuit 70 of the electromagnetic linear actuator 50 will be described with reference to FIGS. 13 is a perspective view showing the center yoke 74, FIG. 14 is a front view of the center yoke 74, and FIG. 15 is a sectional view taken along line XV-XV in FIG.

  The illustrated center yoke 74 is made of a laminated steel plate formed by laminating first to sixth steel plates 74-1 to 74-6 in this order along the front-rear direction Y. By making the center yoke 74 a laminated steel plate, each of the first to sixth steel plates 74-1 to 74-6 can be thinned. As a result, even when each of the steel plates 74-1 to 74-6 is extracted with a press, the problem of sagging can be reduced. Further, by making the center yoke 74 a laminated steel plate, eddy current loss can be reduced as compared with a case where the center yoke 74 is constituted by a single iron plate. As a result, the starting characteristics of the electromagnetic linear actuator 50 can be improved. Further, since a special material such as a sintered yoke or MIM yoke is not used, the center yoke 74 can be manufactured at low cost.

  Anyway, since the center yoke 74 is composed of laminated steel plates, there is no need to change the material. As a result, the accuracy of the components can be increased without changing the magnetic characteristics of the magnetic circuit 70 (electromagnetic linear actuator 50).

  As shown in FIGS. 13 to 15, each of the first to fifth steel plates 74-1 to 74-5 has four concave portions and convex portions at the ends in the vertical direction Z of the pair of side portions 742. 742c is formed. The sixth steel plate 74-6 has four recesses 742d at the ends in the vertical direction Z of the pair of side portions 742. The first to sixth steel plates 74-1 to 74-1 are laminated by stacking the first to sixth steel plates 74-1 to 74-6 with the four recesses and projections 742c and the four recesses 742d being aligned with each other. The alignment of 74-6 can be facilitated and laminated. Further, since the concave and convex portions 742c and 742d are formed in the vicinity of the four corners of the center yoke 74, it is possible to prevent adverse effects on the magnetic flux generated by the pair of plate magnets 72 and 73. . In other words, the magnetic flux interlinking with the coil constituting the sub movable part of the electromagnetic linear actuator 50 is not adversely affected.

  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, a laminated steel plate in which a plurality of steel plates are laminated in the front-rear direction Y is used as the center yoke 74, but a plurality of steel plates are laminated in the width direction (left-right direction) X as the center yoke. Of course, the laminated steel sheet may be used. In the above-described embodiment, only the example in which the composite linear actuator is employed 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.

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. It is the perspective view which looked at the tape drive shown in FIG. 1 from the lower surface side. It is a perspective view which shows the external appearance of the electromagnetic type linear actuator in the composite type linear actuator based on one embodiment of this invention used for the tape drive of FIG. FIG. 4 is an exploded perspective view of the electromagnetic linear actuator shown in FIG. 3. It is the perspective view which looked at the magnetic circuit of the electromagnetic linear actuator shown in FIG. 3 from the upper surface side. FIG. 6 is an exploded perspective view of the magnetic circuit shown in FIG. 5. It is the perspective view which looked at the magnetic circuit of the electromagnetic linear actuator shown in FIG. 3 from the bottom face (lower surface) side. FIG. 8 is an exploded perspective view of the magnetic circuit shown in FIG. 7. It is a perspective view of a compound type linear actuator which omitted a sub movable part in an electromagnetic linear actuator. FIG. 10 is an exploded perspective view of the composite linear actuator shown in FIG. 9. FIG. 10 is a plan view of the composite linear actuator shown in FIG. 9. FIG. 10 is a front view of the composite linear actuator 17 shown in FIG. 9. It is a perspective view which shows the center yoke used for the magnetic circuit of the electromagnetic type linear actuator shown in FIG. It is a front view of the center yoke shown in FIG. FIG. 15 is a cross-sectional view taken along line XV-XV in FIG. 14.

Explanation of symbols

10 Recording / playback device (tape drive)
17 head actuator 17a magnetic head 17b head holder 17c screw 171 lead screw 172 head lift body 172a through hole 1721 bottom surface portion 1722 ceiling portion 1723 central support portion 1724 right support portion 1724a annular projecting portion 1725 extension portion 1725a guide portion 1726 yoke presser 1726 Concave portion 173 Lead screw gear 174 Preload bush 175 Preload spring 176 Metal bearing 50 Electromagnetic linear actuator 60 Sub movable portion 61 Carriage 70 Magnetic circuit 71 York base 711 Bottom yoke 711a Notch portion 712 Front wall yoke 713 Rear wall yoke 72, 73 Plate Magnet 74 Center yoke (laminated steel sheet)
74-1 to 74-6 Steel plate 741 Central portion 742 Side portion 742a Upper protrusion portion 742b Lower protrusion portion 742c Recessed portion and convex portion 742d Recessed portion 75 Upper yoke 75a Notch portion 81 Upper leaf spring 82 Lower leaf spring

Claims (16)

An electromagnetic linear actuator comprising a fixed part and a movable part that moves linearly in the axial direction with respect to the fixed part by electromagnetic force, the fixed part having a magnetic circuit comprising a yoke member and a permanent magnet, In the electromagnetic linear actuator, the movable part includes a coil, and the yoke member is composed of an outer yoke and a center yoke.
The electromagnetic linear actuator, wherein the center yoke is made of a laminated steel plate. The axial direction is the vertical direction of the electromagnetic linear actuator,
The outer yoke is composed of a yoke base and an upper yoke provided at an upper portion of the yoke base, the center yoke is provided at a central portion of the yoke base, and the permanent magnet is accommodated in the yoke base. The electromagnetic linear actuator according to claim 1, comprising a pair of plate magnets.   The yoke base includes a bottom yoke, a front wall yoke extending upward from a front end of the bottom yoke, and a rear wall yoke extending upward from a rear end of the bottom yoke, and the front wall The yoke and the rear wall yoke are spaced apart from each other, and one of the pair of plate magnets is attached to the inner wall of the front wall yoke, and the pair of paired magnets are attached to the inner wall of the rear wall yoke. The electromagnetic linear actuator according to claim 2, wherein the other of the plate magnets is attached, and the center yoke is erected from the center of the bottom yoke between the front wall yoke and the rear wall yoke. . The center yoke includes a central portion and a pair of side portions on both left and right sides of the central portion, and the pair of side portions includes a pair of upper protruding portions that protrude upward from the upper end of the central portion. A pair of lower projecting portions projecting downward from the lower end of the central portion,
The bottom yoke has a pair of notches into which the pair of lower protrusions are inserted,
The upper yoke has a pair of notches into which the pair of upper protrusions are inserted.
The electromagnetic linear actuator according to claim 3. The fixed portion has a head lift body with the magnetic circuit fixed to the front,
The head lift body is provided so as to protrude forward from the upper end thereof, and has a pair of yoke pressers that presses corners at two locations on the rear side of the upper yoke.
The electromagnetic linear actuator according to claim 4.   6. The electromagnetic linear actuator according to claim 5, wherein the pair of yoke retainers have recesses having shapes corresponding to the shapes of the two corners behind the upper yoke. The laminated steel sheet is configured by laminating first to Nth steel sheets (N is an integer of 6 or more) in this order,
In each of the first to (N-1) steel plates, four portions, a concave portion and a convex portion are formed at end portions in the vertical direction of the pair of side portions,
The Nth steel plate has four recesses at the ends in the vertical direction of the pair of side portions,
The electromagnetic linear actuator according to claim 4, wherein the convex is inserted into the concave portion.   The electromagnetic linear actuator according to any one of claims 1 to 7, wherein the movable portion is supported by the upper leaf spring and the lower leaf spring so as to be linearly movable with respect to the fixed portion. A mechanical linear actuator comprising a lead screw having a rotation center axis extending in the axial direction and a main movable portion that linearly moves in the axial direction by rotation of the lead screw, wherein the main movable portion is A composite linear actuator that operates as an electromagnetic linear actuator comprising a fixed portion and a sub movable portion that linearly moves in the axial direction with respect to the sub fixed portion by an electromagnetic force, wherein the sub fixed portion is a yoke member In a composite linear actuator comprising a magnetic circuit comprising a permanent magnet, the sub-movable part comprising a coil, and the yoke member comprising an outer yoke and a center yoke.
A composite linear actuator, wherein the center yoke is made of a laminated steel plate. The axial direction is the vertical direction of the composite linear actuator;
The outer yoke includes a yoke base and an upper yoke provided at an upper portion of the yoke base, the center yoke is provided at a central portion of the yoke base, and the permanent magnet is accommodated in the yoke base. The composite linear actuator according to claim 9, comprising a pair of plate magnets.   The yoke base includes a bottom yoke, a front wall yoke extending upward from a front end of the bottom yoke, and a rear wall yoke extending upward from a rear end of the bottom yoke, and the front wall The yoke and the rear wall yoke are spaced apart from each other, and one of the pair of plate magnets is attached to the inner wall of the front wall yoke, and the pair of paired magnets are attached to the inner wall of the rear wall yoke. 11. The composite linear actuator according to claim 10, wherein the other of the plate magnets is attached, and the center yoke is erected from the center of the bottom yoke between the front wall yoke and the rear wall yoke. . The center yoke includes a central portion and a pair of side portions on both left and right sides of the central portion, and the pair of side portions includes a pair of upper protruding portions that protrude upward from the upper end of the central portion. A pair of lower projecting portions projecting downward from the lower end of the central portion,
The bottom yoke has a pair of notches into which the pair of lower protrusions are inserted,
The upper yoke has a pair of notches into which the pair of upper protrusions are inserted.
The composite linear actuator according to claim 11. The sub-fixed portion has a head lift body through which the lead screw passes and the magnetic circuit is fixed in front.
The head lift body is provided so as to protrude forward from the upper end thereof, and has a pair of yoke pressers that presses corners at two locations on the rear side of the upper yoke.
The composite linear actuator according to claim 12.   14. The composite linear actuator according to claim 13, wherein the pair of yoke retainers have recesses having shapes corresponding to the shapes of the two corners behind the upper yoke. The laminated steel sheet is configured by laminating first to Nth steel sheets (N is an integer of 6 or more) in this order,
In each of the first to (N-1) steel plates, four portions, a concave portion and a convex portion are formed at end portions in the vertical direction of the pair of side portions,
The Nth steel plate has four recesses at the ends in the vertical direction of the pair of side portions,
The composite linear actuator according to claim 12, wherein the convex portion is inserted into the concave portion. The composite linear actuator according to claim 9, wherein the sub movable portion is supported by the upper plate spring and the lower plate spring so as to be linearly movable with respect to the sub fixed portion.

Images