JP5360555B2 - Linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate fitting of a stator 2 and a moving member 3 so as to be coaxial. <P>SOLUTION: In order to position and attach a leaf spring 42 (41) to an outer core 30, a pair of engaging protrusions 303 and 304 is provided to the outer core 30, while a pair of engaged parts 421b and 421b (411b and 411b) into which the pair of engaging protrusions 303 and 304 enters is provided to the leaf spring 42 (41). The engaging protrusions 303 and 304 and engaged parts 421b and 421b (411b and 411b) are both arranged in such direction as the magnetic force of permanent magnets 21 and 22 acts relative to magnetic poles 301 and 302. The engaged parts 421b and 421b (411b and 411b) are cut in such direction as the magnetic force of the permanent magnets 21 and 22 acts relative to the magnetic poles 301 and 302. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a linear actuator that includes a leaf spring that supports a stator and a mover so as to have the same axis and elastically supports the mover so that the mover can reciprocate in a thrust direction. The present invention is applied to a reciprocating motor in which a permanent magnet is provided on the child side, and a magnetic pole portion facing the permanent magnet with a gap in the radial direction is provided on the mover side.

  Conventionally, a linear actuator shown in Patent Document 1 below has been proposed. In this linear actuator, a permanent magnet is disposed at the tip of the bulging portion of the inner surface of the outer core that is a component of the stator, and a coil is wound around the bulging portion. Moreover, the inner core which is a component part of a needle | mover has a magnetic pole part. The magnetic pole part and the permanent magnet are arranged to face each other with a predetermined gap in the radial direction.

  The linear actuator further includes a pair of leaf springs that support the shaft, which is a component of the mover, coaxially with the outer core and elastically support the shaft so that the shaft reciprocates in the thrust direction.

  The leaf spring is formed in a “8” shape when viewed from the axial direction of the shaft. And the insertion hole of a shaft is formed in the location which cross | intersects "8" character shape. Further, the upper and lower insertion openings (annular portions) in the shape of “8” have a size that allows the coil to pass inside. Furthermore, small round holes for attaching to the stator are formed on the center line in the vertical direction at one end and the other end of the leaf spring.

JP 2006-220196 A

  However, in the above-described conventional linear actuator, when the shaft is positioned inside the outer core with the shaft passing through the center of the inner core, the magnetic pole portion of the mover is magnetically attached to the permanent magnet provided on the stator. The predetermined gap described above, that is, the gap for arranging the magnetic pole portion and the permanent magnet to face each other is crushed.

  And in this state (state where the stator and the mover are not the same axis), there is a positional shift between each round hole of the leaf spring and the through hole of the outer core provided corresponding thereto. Therefore, it is difficult to insert a bolt for fastening the outer core and the leaf spring, so that it is difficult to attach the leaf spring to the outer core.

  The present invention has been made in view of the above problems, and when assembling work, when attaching a leaf spring, the magnetic pole portion is magnetically attached to the permanent magnet, and the stator and the mover are not in the same axis. Even if it is, it aims at providing the linear actuator which can correct the state and can make a stator and a needle | mover easy to make the same axial center.

  The present invention supports a stator and a mover arranged inside and outside in the radial direction, supports the stator and the mover so as to have the same axis, and allows the mover to reciprocate in the thrust direction with respect to the stator. And a magnetic pole portion facing the permanent magnet with a gap in the radial direction on the other side of the stator and the mover. In order to position and attach the leaf spring to the stator or the mover arranged radially outward, at least a pair of engaging convex portions is provided on the stator or the mover. The leaf spring is provided with at least a pair of engaging portions into which the engaging convex portions are engaged, and the engaging convex portions and the engaging portions are arranged in directions in which the magnetic force of the permanent magnet acts on the magnetic pole portion. With the, at least a portion of the engaging join the club, characterized in that the magnetic force of the permanent magnet becomes notched in the direction acting on the magnetic pole section.

  When assembling the linear actuator in the assembly work of the linear actuator, normally, the other of the stator and the mover is magnetically attached to one permanent magnet of the stator and the mover, and the stator and the mover have the same axis. There is no state. This means that a positional deviation has occurred between the engaging convex part of the stator or the movable element arranged on the outer side in the radial direction and the engaging part of the leaf spring. However, since at least a part of the engaging portion is notched, it is possible to temporarily attach the leaf spring by engaging the engaging convex portion with the corresponding engaging portion regardless of the positional deviation. Further, when the engaging convex portion is engaged with the engaging portion, the magnetic force between the stator and the mover is forcibly released by the elastic force of the leaf spring so that the stator and the mover have the same axis. It will be corrected.

  In the linear actuator of the present invention, the leaf spring is constituted by a frame portion attached to a stator or a mover arranged radially outside, and a flexible portion provided inside the frame portion, The at least one pair of engaging portions may be provided in the portion.

  According to such a configuration, the leaf spring is divided into two parts: a portion that is attached to the stator or the mover arranged radially outward, and a portion that allows the mover to reciprocate smoothly. Rigidity can be increased, and this makes correction easier.

  Furthermore, according to this invention, the structure which forms the said notch in a U shape can also be selected.

  According to such a configuration, since the notch is formed in a U shape, the above-described engagement convex portion can be easily inserted, and the work efficiency of the assembly work can be further improved.

  In the linear actuator of the present invention, the notch that is notched in the direction in which the magnetic force of the permanent magnet acts on the magnetic pole part is formed in the leaf spring. Therefore, when assembling the leaf spring, the stator and the mover are attached. The other of the stator and the mover is magnetically attached to one of the permanent magnets, and the stator and the mover are not in the same axial center, resulting in a displacement between the engaging convex part and the engaging part. However, the leaf spring can be easily attached, and at this time, the magnetic attachment is forcibly released by the radial rigidity or elastic force of the leaf spring, and the stator and the mover have the same axial center. Therefore, the work efficiency of the assembly work can be improved.

The disassembled perspective view of the linear actuator which shows one Embodiment of this invention. The front view of a leaf | plate spring. The perspective view which looked at the completed linear actuator from the front. The perspective view which looked at the completed linear actuator from back. FIG. 4 is a front view of FIG. 3. The front view which showed the modification of the leaf | plate spring.

  Hereinafter, a linear actuator according to an embodiment of the present invention will be described with reference to the drawings. First, an embodiment of the present invention will be described with reference to FIGS.

  1 is an exploded perspective view of the linear actuator, FIG. 2 is a front view of the leaf spring, FIG. 3 is a perspective view of the completed linear actuator as viewed from the front, and FIG. 4 is a perspective view of the completed linear actuator as viewed from the rear. 5 is a front view of FIG. For convenience, the left side of FIG. 1 is the front side, and the right side is the rear side.

  As shown in these drawings, the linear actuator 1 according to this embodiment includes a stator 2, a mover 3, and leaf springs 41 and 42. The stator 2 is disposed inside the mover 3. The mover 3 is supported so as to be able to reciprocate in the front-rear direction (thrust direction) with respect to the stator 2.

  The stator 2 includes a bobbin 20 in which an inner core (not shown) is inserted, permanent magnets 21 and 22, and a shaft 23. The bobbin 20 is combined with bobbin units 200 and 200 divided into left and right so as to cover the inner core. The bobbin 20 has a coil winding portion in which coils 201A and 201B are wound around one end and the other end. Furthermore, both end surfaces of the bobbin 20 are formed in an arc shape that is convex in the radially outward direction. The permanent magnets 21 and 22 are composed of a first permanent magnet 21 and a second permanent magnet 22 and are fixed to both end faces of the inner core. In addition, the outer surfaces and inner surfaces of the permanent magnets 21 and 22 are formed in an arc shape that is convex outward in the radial direction.

  The shaft 23 is enlarged at the front part compared to the middle part in the axial direction, the enlarged part 231 is formed at the front part, and the male screw part 232 having a smaller diameter than the enlarged part 231 is formed at the rear part. The shaft 23 is inserted from a male screw portion 232 through a through hole (not shown) formed in the central portion of the bobbin 20. A front sleeve 233 having the same diameter as the enlarged portion 231 is inserted between the enlarged portion 231 and the front surface of the bobbin 20. On the other hand, rear sleeves 234 and 235 having the same diameter as the enlarged portion 231 are inserted between the male screw portion 232 and the rear surface of the bobbin 20. Then, a nut N is screwed to the male screw portion 232 of the shaft 23 via the rear sleeves 234 and 235 and the washer W.

  The mover 3 includes a rectangular tubular outer core 30 and flange members 31 and 32. The outer core 30 is a laminated body in which silicon steel plates, which are an example of a magnetic material, are laminated so as to be in close contact with each other in the front-rear direction (axial direction of the shaft 23). A first magnetic pole portion 301 that bulges toward the other end side is integrally provided on one end side of the inner surface of the outer core 30. In addition, a second magnetic pole portion 302 that bulges toward one end side is integrally provided on the other end side of the inner surface of the outer core 30.

  And the opposing surface of the 1st magnetic pole part 301 is opposingly arranged by the outer surface of the 1st permanent magnet 21 via the clearance gap C1 of predetermined width (delta) 1 in a radial direction (refer FIG. 5). The radial direction in this case is a radial direction starting from the center P1 of the bobbin 20. On the other hand, the opposing surface of the second magnetic pole portion 302 is disposed to oppose the outer surface of the second permanent magnet 22 via a gap C2 having a predetermined width δ2 in the radial direction (see FIG. 5). The radial direction in this case is a radial direction starting from the center P1 of the bobbin 20. The width δ1 in the radial direction of the gap C1 and the width δ2 in the radial direction of the gap C2 are set equal.

  The front and rear surfaces of one end portion of the outer core 30 and the front and rear surfaces of the other end portion are respectively provided with holding shaft bodies 303 and 304 as engaging protrusions according to the present invention in the center in the width direction. Is done. More specifically, at one end and the other end of the outer core 30, a through hole is formed in the center in the width direction along the front-rear direction, and the first holding shaft body 303 is formed in the through hole at the one end. The second holding shaft body 304 is inserted through the through hole at the other end while being inserted. And since the holding shaft bodies 303 and 304 are formed longer than the thickness dimension in the front-back direction of the outer core 30, they are the front surface and the rear surface of one end portion of the outer core 30, and the front surface and the rear surface of the other end portion. The end portions of the holding shaft bodies 303 and 304 protrude in the front-rear direction from the center in the width direction.

  Further, the front flange member 31 is overlaid on the outer core 30 via the leaf spring 41 from the front side. On the other hand, the rear flange member 32 is overlaid on the outer core 30 via the leaf spring 42 from the rear side. Then, stoppers 311 and 321 are formed on the flange members 31 and 32 so as to protrude from the left and right sides toward the center in the width direction. The stoppers 311 and 321 are for preventing the stator 2 (or inner core) from coming out of the outer core 30 when the outer core 30 reciprocates. The flange members 31 and 32 are each formed in a rectangular frame shape when viewed from the front, and projecting portions 312 and 322 are formed at one end and the other end. Note that recesses for receiving the end portions of the holding shaft bodies 303 and 304 are formed on the inner surfaces of the projecting portions 312 and 322.

  The front leaf spring 41 is interposed between the outer core 30 and the front flange member 31. On the other hand, the rear leaf spring 42 is interposed between the outer core 30 and the rear flange member 32. The leaf springs 41 and 42 are formed by punching a metal plate having a uniform thickness. As shown in FIG. 2, the leaf springs 41 and 42 are integrally formed from frame portions 411 and 421 that are stacked on the outer core 30 and flexible portions 412 and 422 inside the frame portions 411 and 421. .

  Of the constituent parts of the leaf springs 41 and 42, the frame parts 411 and 421 are sandwiched between the flange members 31 and 32 and the outer core 30 in the front-rear direction. Bolt insertion holes 411a and 421a are formed at the four corners of the frame portions 411 and 421, respectively. In addition, notches 411b and 421b as engaging portions according to the present invention, which are inserted through the end portions of the holding shaft bodies 303 and 304, are formed in a U shape in the center in the width direction of the upper and lower portions of the frame portions 411 and 421. The

  The flexible portions 412 and 422 are formed in a “8” shape when viewed from the front. Then, through holes 4121a and 4221a through which the middle part of the shaft 23 is inserted are formed in the central parts 4121 and 4221 corresponding to the part where the central line of the character “8” intersects. In addition, insertion openings 4122 and 4222 having a size that allows the coil winding portion of the bobbin 20 to pass inside are formed at locations corresponding to the inside of the “8” -shaped annular portion. .

  A central portion 4121 of the front leaf spring 41 is sandwiched between the enlarged portion 231 and the front sleeve 233. On the other hand, the central portion 4221 of the rear leaf spring 42 is sandwiched between the pair of rear sleeves 234 and 235.

  Then, bolts B are inserted in the four corners (insertion holes formed) of the mover 3 in the front-rear direction, and nuts N are fastened to the tips of the bolts B, so that the outer core 30, leaf springs 41, 42, flanges The members 31 and 32 are integrated.

  Here, the flexible portions 412 and 422 will be described in detail with reference to FIG. The flexible portions 412 and 422 need to secure strength at the portions of the notches 411b and 421b, the bolt insertion holes 411a and 421a, and the insertion holes 4121a and 4221a while ensuring flexibility. That is, as described above, the leaf springs 41 and 42 have the shape of “8” and have insertion openings (annular portions) 4122 and 4222 on the upper and lower sides, respectively. The insertion openings (annular portions) 4122 and 4222 have a small distance in the vertical direction and a large distance in the left and right direction, for example, so that the entire plate springs 41 and 42 are easily bent. When viewed from the front, it has a shape equivalent to a rounded barrel shape.

  Further, the end portions of the flexible portions 412 and 422 are located in the vicinity of the notches 411b and 421b, and the portions near the notches 411b and 421b are widened so as to extend toward the notches 411b and 421b. It is formed. The reason for this is that the flexible portions 412 and 422 are bent in the front-rear direction with the vicinity of the notches 411b and 421b as fulcrums.

  Further, the portions of the insertion holes 4121a and 4221a of the plate springs 41 and 42 through which the shaft 23 is inserted are the portions where the displacement amount due to the reciprocating motion of the movable element 3 is the largest, so that the portions are directed toward the center on both the left and right sides. Arc-shaped constrictions 4121b and 4221b are formed. For example, by increasing the surface area of the peripheral portions of the insertion holes 4121a and 4221a as much as possible, the strength against reciprocation is also ensured.

  In the linear actuator 1 configured as described above, the shaft 23 is held at a predetermined position with respect to the mover 3 (outer core 30) by the magnetic force generated from the permanent magnets 21 and 22 when the coils 201A and 201B are not energized. The When the coils 201A and 201B are energized, the mover 3 reciprocates back and forth along the shaft 23 based on the magnetic field generated by the current flowing in the coils 201A and 201B and the direction of the magnetic field generated from the permanent magnets 21 and 22. Move.

  Next, an assembling operation of the linear actuator 1 having the above configuration will be described. First, the bobbin 20 is attached to the inner core to which the permanent magnets 21 and 22 are fixed, and a core completion assembly K in which the coil windings 201A and 201B are wound around the bobbin 20 is prepared.

  Then, a front sleeve 233 and a leaf spring 41 are arranged in front of the core completion assembly K. Then, the male screw portion 232 of the shaft 23 is inserted from the front to the rear through the through hole of the bobbin 20 via the leaf spring 41 and the front sleeve 233.

  In this state, when the bobbin 20 is positioned inside the outer core, one of the first and second magnetic pole portions 301 and 302 of the outer core 30 is placed on one of the first and second permanent magnets 21 and 22 of the bobbin 20. Will be magnetized. Therefore, after the notches 411b and 411b of the leaf spring 41 are engaged with the holding shaft bodies 303 and 304 of the outer core 30, the holding shaft bodies 303 and 304 are inserted into a pair of recesses formed at both ends of the inner surface of the flange 31. Meanwhile, the flange 31 is aligned with the front end surface of the outer core 30.

  Subsequently, the rear sleeve 234, the leaf spring 42, and the rear sleeve 235 are disposed on the shaft 23 inserted through the through hole of the bobbin 20. After the notches 421b and 421b of the leaf spring 42 are engaged with the holding shaft bodies 303 and 304 of the outer core 30, the holding shaft bodies 303 and 304 are inserted into a pair of recesses formed at both ends of the inner surface of the flange 32. While the flange 32 is aligned with the rear end face of the outer core 30, the bolt B is inserted into the front and rear flange members 31, 32 and the bolt insertion holes 411a, 421a of the leaf springs 41, 42. Finally, the bolt B and the nut N are tightened, and the nut N is screwed to the male screw portion 232 of the shaft 23.

  At this time, the shaft 23 is horizontally supported by the front and rear leaf springs 41, 42, and a predetermined distance C 1 between the magnetic pole portions 301, 302 of the outer core 30 and the permanent magnets 21, 22 of the bobbin 20. C2 is reliably maintained.

  In addition, the linear actuator which concerns on this invention is not limited to the said embodiment, A various change is possible in the range which does not deviate from the summary of this invention.

  For example, in the above embodiment, a leaf spring having the frame portions 411 and 421 and the flexible portions 412 and 422 is used. However, as shown in FIG. 6, the frame portions 411 and 421 are not provided, and the flexible portions 412 and 422 are provided. Only the leaf springs 41 ′ and 42 ′ may be used.

  In the above embodiment, the holding shafts 303 and 304 are formed so as to be positioned on the center line in the vertical direction. However, the present invention is not limited to this. For example, the holding shaft bodies 303 and 304 are formed at positions shifted from the center line. Alternatively, it may be formed on a diagonal line. Further, the notches into which the holding shaft bodies 303 and 304 are engaged do not have to be a pair, and one of them may be circular (an engaging portion without a notch), and the remaining may be a notch. May be V-shaped or elliptical.

  In the above embodiment, the outer movable linear actuator has been described. However, the linear actuator according to the present invention may be an inner movable type. In that case, the configurations of the stator and the mover are interchanged.

  DESCRIPTION OF SYMBOLS 1 ... Linear actuator, 2 ... Stator, 3 ... Movable element, 21, 22 ... Permanent magnet, 301, 302 ... Magnetic pole part, 303, 304 ... Holding shaft body (engagement convex part), 41, 42 ... Leaf spring, 411, 421 ... frame part, 412, 422 ... flexible part, 411b, 421b ... notch (engagement part)

Claims (3)

A stator and a mover arranged inside and outside in the radial direction, and a plate that supports the stator and the mover so as to have the same axis and elastically supports the mover so that the mover can reciprocate in the thrust direction. A linear magnet having a spring and a permanent magnet provided on one of the stator and the mover, and a magnetic pole portion facing the permanent magnet with a gap in the radial direction on the other of the stator and the mover. In the actuator
In order to position and attach the leaf spring to the stator or the mover arranged radially outward, the stator or the mover is provided with at least a pair of engaging projections and is engaged with the leaf spring, respectively. At least a pair of engaging portions into which the convex portions are engaged are provided, and each of the engaging convex portions and the engaging portions is arranged in a direction in which the magnetic force of the permanent magnet acts on the magnetic pole portion. At least a part of the linear actuator is cut away in a direction in which the magnetic force of the permanent magnet acts on the magnetic pole part.   The leaf spring includes a frame portion attached to a stator or a movable element arranged on the outer side in the radial direction, and a flexible portion provided inside the frame portion, and the at least one pair of engaging portions is provided in the frame portion. The linear actuator according to claim 1, wherein   The linear actuator according to claim 1, wherein the notch is formed in a U shape.

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