JP2009038874A - Rotary actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a novel rotary actuator which materializes further cost reduction by enhancing the function and assembability while achieving the reduction in parts count and the downsizing. <P>SOLUTION: A rotary actuator is composed of a single electromagnetic coil 3 which is arranged in a case, permanent magnets 7 which have a specified air gap, with their magnetic polarity directions directed to the electromagnetic coil, and are arranged in a different polarity pole juxtaposed state, a rocking arm 5 which holds the magnets and rocks on a plane orthogonal to the direction of their magnetizations, and an output shaft 4 which axially supports the rocking arm and also outputs its rocking as the torque of a reciprocating axis. The holding of the magnets to the rocking arm is in such form that the magnets are arranged on the electromagnetic coil side of the rocking arm, and that a back yoke 6 attracted by the magnets is arranged on the opposite side from the electromagnetic coil thereby catching the rocking arm. Moreover, the core 31 is arranged in the central position of the electromagnetic coil, and a stopper 8 which suppresses the shift of the rocking arm is arranged in the case. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention belongs to the technical field of an electromagnetic rotary actuator that converts electrical energy into rotational force, and particularly relates to a rotary actuator that swings a swing arm by electromagnetic action to output a reciprocating shaft rotational force.

  BACKGROUND ART A rotary actuator as a mechanism for converting input energy into a physical rotational force has been widely used as a power source for movable mechanisms in various industrial machines.

Among such rotary actuators, various configurations for the purpose of reciprocating the output shaft at a predetermined rotation angle by inputting electric energy are disclosed. For example, the configuration of the rotary actuator shown in Patent Document 1 previously filed by the applicant of the present invention is one example.
In this rotary actuator, two electromagnetic coils having a magnetic core disposed at the center are arranged opposite to each other, and a permanent magnet is arranged with an air gap between the electromagnetic coils. The permanent magnet is held by a swing arm supported in a cantilever manner on the output shaft, and swings by an attractive or repulsive action on the permanent magnet by switching the magnetic poles of the electromagnetic coil. This motion was output as a reciprocating shaft rotational force from the output shaft.

Other technologies related to the above rotary actuator include those disclosed as power sources for magnetic disk devices. In this configuration, a carriage main body for moving a magnetic head is disposed between a pair of coil bobbins arranged to face the carriage block with a rotatable support shaft. The carriage is provided with a pair of magnets, and rotates the carriage in conjunction with energization of the coil bobbin (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 10-174409 (2nd page, FIG. 1) JP 63-114558 A (2nd page, FIG. 1)

  In the above-described conventional configuration shown in Patent Document 1, two permanent magnets are arranged side by side on the V-shaped support member constituting the swing arm in different polar directions, so that the magnetic circuit is opened. The permeance coefficient was lowered and the permanent magnet was easily demagnetized. Therefore, depending on the required service life of the industrial machine equipment to be incorporated, it may be necessary to maintain the coercive force.

  Further, since the permanent magnets held by the support member are arranged close to each other with a predetermined air gap in the separation area between the pair of opposed electromagnetic coils, the alignment at the time of assembly and the pair of electromagnetic coils Assembling and wiring setup such as wiring processing has become complicated. Therefore, in addition to the cost of the components themselves, the manufacturing process cannot be simplified or improved in efficiency, and it is difficult to reduce costs.

  Further, the reduction in the number of parts is not limited to cost reduction, but also contributes to ensuring the reliability of the mechanism. Furthermore, in addition to cost reduction, reduction in size and weight of equipment parts or reduction in thickness is an unquestioned requirement, and there has been a demand for the appearance of further improved invention technology in the above-described conventional rotary actuator.

  Accordingly, the present invention proposes to meet the above-mentioned problems and demands, and is a new one that realizes further cost reduction by improving assembly while reducing the number of parts and reducing size and weight of the rotary actuator. A rotary actuator is provided.

In order to solve the above problems, the rotary actuator of the present invention is configured as follows.
That is, a single electromagnetic coil (3) arranged in the case, and a permanent magnet arranged with an air gap and the same magnetic pole direction with respect to the electromagnetic coil (3) and with different poles juxtaposed ( 7), a non-magnetic oscillating arm (5) that holds the permanent magnet (7) and oscillates on a plane perpendicular to the magnetic pole direction of the permanent magnet (7), and the oscillating arm (5) ) And an output shaft (4) for outputting the swing of the swing arm (5) as a reciprocating shaft rotational force.
The specific form of holding the permanent magnet (7) to the swing arm (5) is that the permanent magnet (7) is arranged on the electromagnetic coil side of the swing arm (5) and the permanent magnet is on the anti-electromagnetic coil side. The magnetic body (6) to be attracted is disposed in (7) so as to sandwich the swing arm (5).

  The permanent magnet (7) is held in the swing arm (5) by being embedded in the swing arm (5) from the electromagnetic coil (3) side. In addition, when the magnetic body (6) attracted by the permanent magnet (7) is disposed on the anti-electromagnetic coil side and the swing arm is sandwiched, the electromagnetic arm side of the swing arm is moved from the anti-electromagnetic coil side. It is preferable to form a penetrating embedded portion and to form blocking means for blocking at least the permanent magnet (7) from moving to the anti-electromagnetic coil side. As the structure of the blocking means, for example, a predetermined thick portion (53) is formed inside the embedded portion (51), a claw portion (54) protruding into the inside, a lattice (55) -shaped blocking member, or the like. The formation of can be considered. From another point of view, this blocking means can be said to be a functional part as a clamping part of the swing arm (5) by the permanent magnet (7) and the magnetic body (6).

  In the rotary actuator (1) having such a configuration, the swing arm (5) swings due to the attraction or repulsive force acting on the permanent magnet (7) by switching the magnetic polarity of the electromagnetic coil (3). By this swinging, it is taken out from the output shaft (4) as a kinetic force rotating in a reciprocating axis.

Further, in the holding of the permanent magnet (7) of the swing arm (5), the permanent magnet (7) is disposed on the electromagnetic coil side of the swing arm (5) and the swing arm (5) at a position corresponding to this. It is preferable to dispose a magnetic body attracted by the permanent magnet (7), specifically, a yoke (6) that prevents leakage of magnetic flux on the anti-electromagnetic coil side of the permanent magnet (7) on the opposite side of . Due to the arrangement of the yoke (6), the swing arm (5) is sandwiched between the permanent magnet (7) and the yoke (6). The yoke (6) has two magnetic poles concentrated on the electromagnetic coil side by forming a closed magnetic path on the side of the permanent magnet (7) disposed on the swing arm (5) in a so-called different pole parallel state. When combined with the permanent magnet (7), it can function as a state of a U-shaped magnet.
In addition, the configuration in which the different poles of the permanent magnet (7) are juxtaposed is the case where the two permanent magnets (7) are used to form a so-called different pole parallel state, and a single ferromagnetic material is poled anisotropically. This includes the case where it is formed by being magnetized.

  Further, a columnar magnetic core (31) may be disposed at the center position of the electromagnetic coil (3). When the electromagnetic coil (3) is not energized, the core (31) is magnetically attracted by the closer permanent magnet (7), and the swing arm (5) is held at a swing position of a predetermined angle. The output shaft (4) supporting the shaft is also maintained in a state where the rotation is stopped.

  As described above, the stopped state after swinging can also be maintained by the core (31). In addition, a stopper (8) for restricting the movement of the swinging arm (5) is disposed inside the case. Also good. That is, the stopper (8) is provided so that the swing arm (5) does not interfere with the inner wall of the case (2) as necessary, and is not an essential component.

  Note that the reference numerals in parentheses described in the claims and the means for solving the above-described problems are added with reference numerals for easy understanding of the configuration of the invention. Of course, it is not limited to the above form.

The rotary actuator of the present invention has the following effects by adopting the above configuration.
That is, the present invention is characterized in that it is composed of only a single electromagnetic coil, excluding the conventional configuration in which two pairs of electromagnetic coils are arranged so as to sandwich the swing arm. The size and weight are reduced by reducing the number of parts without reducing reliability and functionality. This unification of the electromagnetic coils facilitates the positioning at the time of assembling and the assembling property such as wiring processing to the electromagnetic coils and the setup thereof, and as a result, contributes to the cost reduction effect.

  In addition, since a yoke (hereinafter referred to as “back yoke”) is disposed on the anti-electromagnetic coil side of the swing arm, a closed magnetic circuit is formed for the permanent magnets disposed on the swing arm in a different pole parallel state. It will be. As a result, there is no leakage of magnetic flux on the anti-electromagnetic coil side of the permanent magnet, and almost all of the magnetic flux can be concentrated on the electromagnetic coil side, increasing the coercive force of the magnet and increasing the driving force when the swing arm moves. be able to. In addition, a closed magnetic path is formed through the back yoke, the permeance coefficient of the permanent magnet is improved, and the permanent magnet is difficult to demagnetize. In other words, due to the presence of the back yoke, it is possible to form a so-called high permeance state even if the permanent magnet is formed in a thin state where the NS poles are brought close to each other. This means that it is possible to maintain a state in which demagnetization is difficult. As a result, the thickness of the entire actuator can be reduced, which has the effect of contributing to a reduction in size and thickness. In addition to this, the function of the rotary actuator can be maintained and improved, and a permanent magnet having a low coercive force can be used at a low cost. In this respect, the cost can be reduced.

  Furthermore, there is an advantage that the attaching operation of the permanent magnet to the swing arm is facilitated by attaching the back yoke. In other words, in the past, the permanent magnet was often attached to the swing arm, which was often formed by resin molding, by adhesion or insert molding. However, in the present invention, the swing magnet is shaken by the magnetic attraction between the permanent magnet and the back yoke. Since the moving arm is sandwiched, the degree of freedom in forming the swing arm is increased and the operation can be simplified. In addition, the assembly performance of wiring processing etc. to the permanent mold of the permanent magnet and its setup make the magnetic attractive force act, so even if it is used for a long period of time, there is a problem such as dropping of the permanent magnet from the embedded part. The occurrence rate can be significantly reduced.

  In addition, since the core is arranged at the center of the electromagnetic coil, when the electromagnetic coil is energized, it increases the force that moves the swing arm as a magnetic path that directs the magnetic flux generated in the electromagnetic coil to the permanent magnet side. The output torque is improved. On the other hand, when no power is supplied, the residual magnetic flux of the core is magnetically attracted to the permanent magnet, and the stopped state of the swing arm can be maintained. As a result, the rotational position of the rotary actuator can be maintained in a non-energized state, and the reliability of the device can be improved while reducing power.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS The best embodiment of a rotary actuator (hereinafter abbreviated as “actuator”) according to the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a partially cutaway perspective view showing the structure of the actuator of this embodiment example, FIG. 2 is an assembled perspective view showing the actuator of this embodiment example, and FIG. 3 shows the swing of the actuator of this embodiment example. FIGS. 4A and 4B are assembled perspective views showing a modification of the arm, FIG. 4 is a partially cutaway plan view showing the actuator of the embodiment, and FIG. 5 is a cross-sectional view taken along line AA in FIG. is there.

  The actuator 1 according to this embodiment rotates the output shaft 4 projecting outside the case 2 with a predetermined driving force between a certain angle. The actuator 1 mainly includes the case 2 and an electromagnetic wave disposed inside the case 2. The coil 3, the output shaft 4, the swing arm 5, and a permanent magnet 7 (hereinafter abbreviated as “magnet”). Note that the actuator 1 according to the present embodiment has no vertical relationship in consideration of gravity, but will be described below using the vertical relationship according to the drawing of the drawings for convenience of description.

  The case 2 shown in the figure has a bottomed cylindrical shape, and its upper opening is closed with a cover plate 22 except for a through portion of the output shaft 4. The material of the case 2 and the cover plate 22 is generally formed of a magnetic material such as iron in order to prevent magnetic path formation or magnetic flux leakage of the electromagnetic coil 3 and the magnet 7 disposed therein. However, the present invention is not limited to this, and a resin material or a resin molded product in which magnetic powder is mixed may be used.

  An electromagnetic coil 3 wound in a direction parallel to the case bottom surface 21 is placed and fixed at a position slightly deviated from the center of the bottom surface 21 inside the case. At the center position of the winding of the electromagnetic coil 3, a core 31 made of a columnar magnetic body having substantially the same height as the electromagnetic coil 3 is arranged in an upright manner.

  The output shaft 4 is arranged upright on the bottom surface 21 inside the case at a position where it does not interfere with the electromagnetic coil 3. The output shaft 4 protrudes from the cover plate 22 at the upper end side, and is provided with bearings 41 at two locations on the bottom surface side of the case 2 and the case inner side of the cover plate 22, and is rotatable with respect to the case 2 and the cover plate 22. It is said. In the present embodiment, the output from the output shaft 4 is obtained from the cover plate 22 side, but it may be obtained from the bottom surface 21 side and is appropriately selected.

  A swing arm 5 made of a resin material is attached and fixed to the output shaft 4 inside the case so as to be mounted. The swing arm 5 has a substantially fan-like shape when viewed from above, and has a height (a height that can secure an air gap, which will be described later) by extending the main part of the fan-shaped downward to avoid interference with the electromagnetic coil 3. ), And is integrally attached to the output shaft 4. The swing arm 5 is formed so that most of the fan-shaped fan surface overlaps the central position of the electromagnetic coil 3 and at least the core 31. The swing arm 5 having such a configuration is arranged so that the lower surface side faces the electromagnetic coil 3 with a so-called air gap having a predetermined gap, and can freely rotate and reciprocate (hereinafter referred to as “swing”) inside the case. The shaft is supported by the output shaft 4.

  Two recesses 51 are formed on the lower surface side of the portion of the swing arm 5 that overlaps the electromagnetic coil 3, that is, the side facing the electromagnetic coil 3 and the core 31, and the magnet 7 is embedded from below. Or by press-fitting. The magnet 7 has a rectangular block shape, and the lower surface thereof is substantially flush with the lower surface of the swing arm 5. Further, the magnet 7 is magnetized with a magnetic pole direction along a direction perpendicular to a surface along the direction in which the swing arm 5 swings (hereinafter referred to as “swing surface”). Further, the two magnets 7 and 7 arranged in parallel are attached to the swing arm 5 so that the directions of the magnetic poles are opposite to each other ("different pole parallel state"). The magnet 7 employed in the present embodiment is preferably a neodymium magnet having a strong coercive force.

  A concave portion 52 having a size covering the upper surfaces of the two magnets 7 and 7 is formed in the fan surface portion on the upper surface side of the swing arm 5, and a back yoke 6 having an appropriate shape is embedded in the concave portion 52. Is arranged. The back yoke 6 is set to a size that overlaps the upper surface of the two magnets 7 described above. In addition, the swing arm 5 leaves a thin wall portion 53 having a predetermined thickness between the magnet recess 51 and the yoke recess 52. The thin portion 53 functions as a sandwiching portion between the magnet 7 and the back yoke 6. Note that the form of the portion to be held is not limited to the thin portion 53, and as shown in FIG. 3, claw portions 54 and lattices 55 that cannot move the magnet 7 to the back yoke side are provided. It is good also as a form to form.

  As described above, the magnet 7 and the back yoke 6 are fixed to the swing arm 5 by holding the thin portion 53 of the swing arm 5 with their magnetic attraction force. For this reason, when compared with a conventional fixing method, for example, a bonding method using an adhesive, or a fixing method using an insert mold in which a magnet 7 is previously placed in a resin mold and integrated with the magnet 7 during resin molding, the fixing work This has a remarkable effect of facilitating the process and reducing the cost.

  A closed magnetic circuit (closed magnetic circuit) is formed by the back yoke 6 arranged on the anti-electromagnetic coil side in the two magnets 7 and 7 arranged in the different pole parallel state on the swing arm 5. Thereby, the leakage of magnetic flux on the side of the anti-electromagnetic coil is almost eliminated, and the magnetic flux of the two magnets 7 is concentrated on the electromagnetic coil side, so that the two magnets 7 can be used like a U-shaped magnet, and the coercive force is reduced. Will be prevented.

In addition to the above configuration, two stoppers 8 are arranged on both sides of the swing surface of the swing arm 5. This stopper 8 is formed by standing a cylindrical body from the bottom surface 21 of the case, and suppresses the movement of the swing arm 5 (or sets the swing angle) and prevents interference with the inner wall of the case 2. Here, the moving range (swinging range) of the swing arm 5 by the stopper 8 is a range in which the two magnets 7 and 7 cover the core 31 of the electromagnetic coil 3 in a top view as shown in FIG. Yes. The stopper 8 disposed as a separate body can be designed, for example, by changing the design of the size of the swing arm 5 and the like so that the inner wall of the case 2 can function as the stopper 8 or can be integrally formed. It can be omitted.
[Operation of this embodiment]

The actuator 1 according to this embodiment having the above-described configuration operates as follows.
First, as shown in FIGS. 4 and 5, even if the swing arm 5 is in a non-energized state, the magnetic attraction action between the magnet 7a on one side and the core 31 and the contact restriction of the stopper 8a are compatible. Crawling and stopping. This state is the initial state.

  Next, when the electromagnetic coil 3 is energized, the electromagnetic coil 3 is excited and a repulsive force exceeding this is applied to the magnet 7a attracted by the core 31, so that the swing arm 5 moves in the opposite direction (arrow m). Will move. This movement is output from the output shaft 4 as a rotational axial force. And even if it is made into a non-energized state in this movement position (two-dot chain line display), while the other magnet 7b which has moved is attracted | sucked to the core 31, a stop state will be maintained by the control by the stopper 8b. .

  As described above, the direction of the excitation current to the electromagnetic coil 3 is appropriately changed to swing the swing arm 5 to obtain the reciprocating shaft rotational force (output torque) from the output shaft 4.

The actuator 1 according to the present embodiment also has a feature that it can maintain a state in which the output shaft 4 is braked by magnetic attraction when the residual magnetic flux of the magnet 7 and the core 31 is acted on.
[Possibility of other embodiments]

  The actuator 1 according to the present embodiment has a back yoke 6 disposed on the swing arm 5 to form a closed magnetic path for the magnet 7 disposed in a different-polarity parallel state, and the holding force of the magnet 7 on the swing arm 5. However, an actuator 9 having the following configuration may be used.

  That is, as shown in FIG. 6, the actively arranged back yoke 6 is omitted, but the cover plate 22 of the case 2 is made of a magnetic material, and the cover plate 22 covers the two magnets 7 and 7. Is made to function as a back yoke. However, the swing arm 5 needs to have a gap that does not interfere with the cover plate 22. Further, the separation distance between the swing arm 5 and the cover plate 22 needs to adjust the magnetomotive force of the electromagnetic coil 3 so that the magnet 7 does not fall out of the swing arm 5 toward the electromagnetic coil side when energized.

  The actuator 9 having such a configuration is difficult to generate a driving force for adjusting the magnetomotive force of the electromagnetic coil 3 described above. However, since the actuator 9 has a simple structure, it can be expected to be used in a low output application.

It is a partially cutaway perspective view showing the structure of the actuator of this embodiment. It is an assembly perspective view showing the actuator of this embodiment. It is an assembly perspective view (A) and (B) which show the modification of the swing arm of the actuator of this embodiment. It is a partially notched top view which shows the actuator of the example of this embodiment. It is AA sectional view taken on the line of FIG. It is sectional drawing which shows the actuator of the other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 2 Case 21 Bottom 22 Cover plate 3 Electromagnetic coil 31 Core 4 Output shaft 41 Bearing 5 Swing arm 51 Recessed part (for magnet)
52 recess (for yoke)
53 Thin-walled portion 54 Claw portion 55 Grid 6 Back yoke 7 Magnet 8 Stopper 9 Actuator (other forms)

Claims (5)

A single electromagnetic coil (3) placed in the case;
A permanent magnet (7) disposed with an air gap and a magnetic pole direction aligned with the electromagnetic coil (3), with the different poles juxtaposed;
A non-magnetic oscillating arm (5) holding the permanent magnet (7) and oscillating on a surface orthogonal to the magnetic pole direction of the permanent magnet (7);
An output shaft (4) for supporting the swing arm (5) and outputting the swing of the swing arm (5) as a reciprocating shaft rotational force;
A rotary actuator characterized by comprising: In holding the permanent magnet (7) on the swing arm (5),
The permanent magnet (7) is disposed on the electromagnetic coil side of the swing arm (5), and the magnetic body (6) attracted by the permanent magnet (7) is disposed on the anti-electromagnetic coil side, so that the swing arm (5 The rotary actuator according to claim 1, wherein: In the arrangement of the magnetic body (6) attracted by the permanent magnet (7),
3. The rotary actuator according to claim 1, wherein the rotary actuator is arranged so as to prevent leakage of magnetic flux to the anti-electromagnetic coil side of the permanent magnet (7).   The rotary according to claim 1, 2 or 3, wherein a core (31) made of a magnetic material is arranged at the center position of the electromagnetic coil (3) so as to face the permanent magnet (7) with an air gap. Actuator.   The rotary actuator according to claim 1, 2, 3 or 4, further comprising a stopper (8) for restricting movement of the swing arm (5) in the case.

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