JP2006304469A - Actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an actuator that rotates reciprocatably, capable of reducing the number of parts and diameter for downsizing. <P>SOLUTION: This actuator includes a permanent magnet 2 polarized in a direction crossing an axial direction of a shaft 1, yokes 5 provided on both sides of a coil 4 in an axial direction, and a pole portion 7 protrudingly provided so as to face the permanent magnet 2 from an inner periphery surface of the yokes 5 on both the sides in the axial direction toward a moving device 3 side respectively. The permanent magnet 2 is formed in a plate shape extended in the axial direction of the shaft 1, and a magnet auxiliary member 12 which simultaneously faces the pole parts on both the sides of the surface is provided on a stator side of the permanent magnet in the axial direction. A positional relation between the pole portion 7 and the pole of an outer periphery surface of the permanent magnet 2 is set so that a magnetic relation between the repellency and attraction for the pole of the pole part 7 provided at one yoke 5a during application of current to the coil 4 and the mating pole on the outer surface side of the permanent magnet 2, and that between the repellency and attraction for the pole of the pole portion 7 provided at the other yoke 5b and the mating pole on the outer surface side of the permanent magnet 2 may become the same. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an actuator and, for example, to an actuator that is used for a hand-held product and is suitable for reciprocating rotational driving by forward and reverse rotation within a predetermined angle range.

  2. Description of the Related Art Conventionally, for example, an actuator disclosed in Patent Document 1 is known as an actuator that performs reciprocating rotational drive by rotating forward and backward within a predetermined angle range.

  The actuator according to the conventional example shown in Patent Document 1 includes a mover having a permanent magnet on a shaft, and a coil and a tube wound in a circumferential direction so as to be rotatably supported so as to surround the mover. And a stator having a yoke body made of a magnetic material. Then, by applying an alternating current to the coil, the mover is reciprocally rotated at a predetermined angle around the shaft. The yokes constituting the yoke body are provided on both sides in the axial direction of the coil, and the yokes on both sides are magnetically connected with a magnetic body.

  The mover is configured by providing a permanent magnet on the outer periphery of the shaft. And the shaft which provides a permanent magnet is comprised with the magnetic body for the purpose of reducing magnetic resistance, increasing the amount of magnetic flux, raising torque, and enabling the highly efficient and high torque rotational drive. The mover is held by rotatably supporting a shaft on bearings provided at both ends in the axial direction of a cylindrical shield case so as to freely rotate in the rotational direction. The mover is inserted into the stator with a predetermined gap in the shield case. Further, the mover connects both sides in the axial direction of the portion where the permanent magnet is provided by an elastic body such as a spring. The movable element and the elastic body constitute a vibration system of reciprocating rotational motion around the shaft.

In the actuator configured as disclosed in Patent Document 1, a permanent magnet and a magnetic body are provided on the outer peripheral portion of the shaft, and the outer surface portion of the magnetic body and the outer surface portion of the permanent magnet are provided in the direction around the axis, and The outer surface of the permanent magnet faces the stator.
JP 2004-343930 A

  In the actuator as disclosed in Patent Document 1, when the number of plate-like permanent magnets 21 is reduced to half as shown in FIG. 5, the distance between the magnetic pole part 71 of the stator 61 and the mover 31 is reduced. There is a problem that L becomes large, the magnetic resistance becomes high correspondingly, and the torque is greatly reduced.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide an actuator that can rotate without deteriorating performance even when the number of permanent magnets used is reduced.

  In order to achieve the above object, the actuator according to the first aspect of the present invention is a coil in which a mover having a permanent magnet provided on a shaft via a magnetic body is wound in a circumferential direction so as to surround the mover. And an actuator that is rotatably supported in a stator having a yoke made of a cylindrical magnetic body, and applies a current to the coil to reciprocate the movable element around a shaft at a predetermined angle. The yoke is provided on both sides in the axial direction of the coil, and magnetic pole portions are periodically protruded in the rotational direction at different positions from the inner peripheral surfaces of the yokes on both sides in the axial direction toward the mover side, The permanent magnet is formed in a plate shape extending in the axial direction magnetized in a direction orthogonal to the axial direction of the shaft, and is provided on the surface of the magnetic body. Characterized in that a magnetic auxiliary member that can simultaneously face on both sides of the magnetic pole portions.

  The actuator according to the second aspect of the present invention is the actuator according to the first aspect, wherein the magnetic auxiliary member is provided so as to cover the entire surface of the permanent magnet on the stator side, and the magnetic body and the The outer surface of the movable element, which is a magnetic auxiliary member, and the inner surface of the magnetic pole portion form a concentric circle centered on the shaft.

  According to the actuator of the first aspect of the present invention, the permanent magnet of the mover in which the permanent magnet is provided on the shaft via the magnetic material is magnetized in a direction perpendicular to the axial direction of the shaft. It is formed in a plate shape extending in the direction, and a magnetic auxiliary member capable of simultaneously facing the magnetic pole portions on both sides in the axial direction is provided on the surface of the permanent magnet on the stator side. In this case, since a plate-like permanent magnet is used, it is easy to produce and the cost can be reduced. Moreover, since the magnetic auxiliary member is used, the gap between the permanent magnet and the magnetic pole part can be reduced, and the permanent magnet N pole → magnetic auxiliary member → gap → magnetic pole part → gap → magnetic auxiliary member → permanent magnet S pole magnetism Torque can be improved by reducing the magnetic resistance of the circuit. As a result, the distance between the stator and the mover of the actuator that drives reciprocating rotation can be reduced, the number of plate-like permanent magnets used can be reduced without deteriorating the performance, the diameter can be reduced, and the size can be reduced. realizable.

  According to the actuator according to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the torque can be further improved, and the air resistance and wind noise can be reduced by suppressing the turbulence of the air generated during operation. The dynamic characteristics can be improved.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. 1 to 3 are views showing an embodiment of the present invention. FIG. 1 is a cross-sectional view of the entire structure of the actuator in a direction parallel to the axial direction. FIG. FIG. 3 is a cross-sectional view taken in a direction orthogonal to the partially omitted axial direction for explaining the operating principle.

  This actuator includes a mover 3 having a permanent magnet 2 provided on the outer periphery of a shaft 1 via a magnetic body 8 and a magnetic auxiliary member 12 provided on the outer surface thereof, yokes 5a disposed on both sides of the coil 4, It is comprised from the cylindrical stator 6 provided with 5b. The mover 3 is supported so as to be rotatable about an axis, and the stator 6 has a cylindrical shape so that the mover 3 is rotatably inserted around the axis. The cylindrical stator 6 is housed in a shield case 9 made of a cylindrical magnetic material so that the outer shape is substantially columnar.

  In the stator 6, the coil 4 is wound around the coil bobbin 10, and cylindrical yokes 5 (yoke 5 a and yoke 5 b) having an inner diameter smaller than that of the coil bobbin 10 are provided on both sides (upper and lower in FIG. 1) of the coil bobbin 10. The yokes 5a and 5b on both sides are magnetically connected by the magnetic body 11, and a plurality of magnetic pole portions 7 and 7a protrude toward the movable element 3 from the inner peripheral portions of the yokes 5a and 5b on both sides. It is composed.

  In the mover 3, the shaft 1 is made of a magnetic material, the magnetic resistance is reduced, the amount of magnetic flux is increased, the torque is increased, and high-efficiency, high-torque rotational driving is possible. A magnetic body 8 is provided on the shaft 1, and a permanent magnet 2 is embedded in the magnetic body 8 in parallel with the shaft 1. In this case, the magnetic body 8 is formed in a substantially cylindrical shape surrounding the shaft 1, and the plate-like permanent magnet 2 is disposed and embedded in an axially symmetric position around the shaft 1 on the outer periphery of the magnetic body 8. .

  Further, the permanent magnet 2 has a rectangular flat plate shape, and a plurality (two in this example) are provided around the axis of the shaft 1 in an axisymmetric manner. Each permanent magnet 2 is magnetized so that the outer surface and the inner surface in the direction intersecting the axial direction of the shaft 1 have different polarities as shown in FIG. 2 and FIG. The magnetic poles on the outer surface are the same. That is, it is magnetized so that only one pole of the N pole or S pole is on the outer peripheral surface side in the direction around the axis. As described above, the permanent magnet 2 is provided on the outer peripheral portion of the shaft 1 via the magnetic body 8, and the magnetic auxiliary member 12 is provided to constitute the mover 3.

  Further, the mover 3 uses the rare earth permanent magnet 2 so as to increase the amount of magnetic flux to increase the torque and enable high-efficiency and high-torque rotational drive. The mover 3 is inserted into the stator 6 with a predetermined gap in a cylindrical shield case 9. Further, the movable element 3 is held by the shaft 1 being rotatably supported by bearings 14 provided at both ends in the axial direction of the cylindrical shield case 9 so that the movable element 3 can freely rotate in the rotational direction. Has been. Further, the movable element 3 has both sides in the axial direction of the portion where the permanent magnet 2 is provided connected by an elastic body 13 such as a spring, and the movable element 3 and the elastic body 13 are reciprocatingly rotated around the shaft 1. This constitutes the vibration system.

  The stator 6 has a cylindrical shape (cylindrical in this example), and is housed in a shield case 9 made of a cylindrical magnetic body. The stator 6 has a coil 4 wound around a coil bobbin 10 and a cylindrical (annular) yoke 5 (yoke 5a, yoke 5b) having an inner diameter smaller than that of the coil bobbin 10 on both sides of the coil bobbin 10. And a plurality of magnetic pole portions 7 and 7a projecting from the inner peripheral portions of the yokes 5a and 5b toward the mover 3 and the magnetic body 11 and the like.

  The plurality of magnetic pole portions 7 and 7a are provided so as to face the permanent magnets 2 provided on both sides in the axial direction of the coil 4 from positions spaced apart in the axial direction of the shaft 1 made of a magnetic material. Yes. The magnetic pole portions 7 and 7 a protrude from the inner peripheral portions of the yokes 5 a and 5 b on both sides toward the mover 3, and the yokes 5 a and 5 b on both sides are magnetically connected by the magnetic body 11. In the present embodiment, the magnetic pole portions 7 and 7a constituting the stator 6 are arranged and protruded by two from the inner circumferences of the yokes 5a and 5b at intervals of 180 ° in the direction around the axis. In the invention, the number of the magnetic pole portions 7 and 7a is not limited to this.

  Here, the relationship between the magnetic pole portions 7 and 7a provided in both yokes 5a and 5b and the magnetic poles on the outer surface of the permanent magnet 2 facing the magnetic pole portions 7 and 7a is set as follows. That is, when an electric current is passed through the coil 4, the magnetic relationship between repulsion and attraction between the magnetic pole of the magnetic pole portion 7 provided on one yoke 5a and the magnetic pole on the outer surface side of the permanent magnet 2 of the mover 3 opposed thereto. The repulsion between the magnetic pole of the magnetic pole portion 7a provided on the other yoke 5b and the magnetic pole on the outer surface side of the permanent magnet 2 of the mover 3 opposite to this, and the magnetic relationship of attraction are reversed and the rotation in the same direction The positional relationship between the positions of the magnetic pole portions 7 and 7a provided in the yokes 5a and 5b on both sides in the direction around the axis and the magnetic poles on the outer surface of the permanent magnet 2 is set so that torque is generated.

  That is, it is movable by the magnetic relationship of repulsion and attraction between the magnetic pole of the magnetic pole portion 7 provided on one yoke 5a and the magnetic pole on the outer surface side of the magnetic auxiliary member 12 provided on the permanent magnet 2 of the movable element 3 facing the yoke 5a. When generating torque for rotating the child 3 around the axis, the magnetic pole of the magnetic pole portion 7a provided on the other yoke 5b and the magnetic pole on the outer surface side of the magnetic auxiliary member 12 provided on the permanent magnet 2 of the mover 3 opposite to the magnetic pole 7a. The magnetic pole portions 7 and 7a provided on the yokes 5a and 5b on both sides and the permanent members respectively facing the magnetic pole portions 7 and 7b so as to generate a torque that rotates the mover 3 in the same direction as described above due to the magnetic relationship between repulsion and attraction. A magnetic relationship with the magnet 2 is set.

  The yokes 5a and 5b may be magnetically connected by a shield case 9 made of a magnetic material to form one yoke body by the yokes 5a and 5b on both sides and the shield case 9, or the yokes 5a on both sides. 5b and the magnetic body 11 may be integrated to form an integral yoke body.

  Next, the operation principle of this embodiment will be described. When a current in one direction flows through the coil 4, different poles are generated in the magnetic pole portion 7 provided in one yoke 5a in the axial direction and the magnetic pole portion 7a provided in the other yoke 5b in the coaxial direction. For example, assuming that an N pole is generated in the magnetic pole portion 7 provided in one yoke 5a in the axial direction and an S pole is generated in the magnetic pole portion 7a provided in the yoke 5b located on the other side, both yokes 5a on both sides of the coil 4 are provided. Clockwise torque is generated between the magnetic pole portions 7 and 7a provided on 5b and the permanent magnet 2 of the mover 3, respectively, and the mover 3 rotates clockwise. Further, when a current in the other direction is passed through the coil 4, different poles are generated in the magnetic pole portion 7 provided in the one yoke 5a in the axial direction and the magnetic pole portion 7a provided in the other yoke 5b in the coaxial direction. 4, counterclockwise torque opposite to the above is generated between the magnetic pole portions 7, 7 a provided on both yokes 5 a, 5 b on the both sides of 4 and the permanent magnet 2 of the mover 3. Rotates counterclockwise.

  Therefore, by passing an alternating current through the coil 4, the mover 3 can be reciprocally rotated about the shaft 1 at a predetermined angle. At that time, a magnetic circuit of the permanent magnet 2 → the magnetic auxiliary member 12 → the gap → the magnetic pole portion 7 (7a) → the gap → the magnetic auxiliary member 12 → the permanent magnet 2 is formed. Here, the magnetic auxiliary member 12 is used. Therefore, the gap between the permanent magnet 2 and the magnetic pole part 7 (7a) can be reduced, the magnetic resistance of the magnetic circuit can be reduced, and the torque can be improved. In addition, the magnetic circuit is formed in a substantially elliptical shape that is long inside and outside along the axial direction of the shaft 1, and this magnetic circuit acts to shorten the path from the inclined state to the parallel state. The rotational torque is generated.

  In the above embodiment, the rectangular and flat magnetic auxiliary member 12 is bonded to the outer surface of the plate-like permanent magnet 2 in parallel with the axis. Even if the plate-like permanent magnet 2 is used, the outer surface portion of the magnetic auxiliary member 12 functions as a magnet with the same magnetic pole as the magnetic pole of the outer surface portion of the permanent magnet 2 and there is a different magnetic pole around the axis. The gap between the magnetic pole part 7 (7a) and the permanent magnet 2 is substantially reduced. Therefore, the size and quantity of the expensive permanent magnet 2 can be reduced as compared with the conventional one, and a low-cost actuator can be realized. Furthermore, the magnetic resistance seen from the magnetomotive force side can be reduced.

  Next, another embodiment of the present invention will be described with reference to FIG. Since the overall configuration is the same as that of the above-described embodiment, the same reference numerals are given to portions that perform the same function, and detailed description thereof is omitted.

  In the above-described embodiment, the permanent magnet 2 has a rectangular flat plate shape, and a magnetic auxiliary member 12 having a small rectangular plate shape is provided on the surface of the stator 6. The magnetic path passes through the mover 3 and the stator 6. The magnetic resistance is reduced. However, in the above embodiment, since there is a large gap between the magnetic auxiliary member 12 and the stator 6, it cannot be said that the magnetic resistance is sufficiently reduced, and there is room for reducing the size. .

  Therefore, in the present embodiment, the magnetic auxiliary member 12a having an arc shape in cross section is provided on the outer surface of the permanent magnet 2, and the outer surface is formed in an arc shape, thereby making the thickness of the gap layer substantially constant and smaller. ing. As a result, the magnetic resistance of the magnetic path can be further reduced, the torque can be further improved, and air characteristics and wind noise can be reduced by suppressing air turbulence that occurs during operation, thereby improving dynamic characteristics. .

  That is, as shown in FIG. 4, this actuator is also composed of a mover 3 and a cylindrical stator 6. In the mover 3, a magnetic member 8 is provided on the outer periphery of a shaft (not shown). The two permanent magnets 2 are embedded in the magnetic member 8 so as to be symmetrical with respect to the axis parallel to the axis and bonded, and a magnetic auxiliary member 12 a is provided on the outer surface of the permanent magnet 2. The stator 6 is configured in a cylindrical shape having yokes arranged on both sides of a coil (not shown). The mover 3 is supported so as to be rotatable around an axis, and the mover 3 is inserted into the stator 6 so as to be rotatable around the axis.

  The magnetic auxiliary member 12 a is formed in an arc shape in cross section, and is bonded to the outer surface of the permanent magnet 2 to constitute the mover 3, and is arranged concentrically with the inner peripheral surface of the stator 6. In this case, since the gap between the magnetic pole portion 7 (7a) of the stator 6 and the mover 3 can be made smaller, the magnetic resistance can be reduced and the size can be further reduced. Moreover, an expensive permanent magnet can be made small and a plate-shaped thing can be used. In addition, since the thickness of the gap can be made constant, the air resistance and wind noise can be reduced, and the dynamic characteristics can be further improved.

  Since the operation principle of this embodiment is the same as that of the above embodiment, the description thereof is omitted here. In the above-described two embodiments, the magnetic pole portion protrudes from a position spaced in the axial direction of the shaft, but in the present invention, of course, the invention is not limited thereto. It is good also as a structure where a magnetic pole part is not interposed between a coil and a needle | mover. With this configuration, the diameter of the actuator can be reduced as compared with the conventional example in which the magnetic pole tooth portion serving as the magnetic pole portion is disposed between the coil already described and the permanent magnet of the mover. Therefore, the diameter and size of the actuator can be reduced. It can be planned.

  In addition, if the magnetic pole part protrudes from the shaft so as to face the permanent magnets provided on both sides of the coil in the axial direction from a position spaced apart in the axial direction of the shaft, the force is applied at a location far from the shaft. It is possible to generate a large torque by taking a wide facing area. When the actuator of the present invention is applied to various electric devices such as an electric toothbrush, in particular, a hand-held product, the diameter of the grip portion can be reduced, and the actuator is suitable for ease of use.

It is sectional drawing in the direction parallel to the axial direction which shows the whole structure of the actuator of this invention. It is the perspective view which fractured | ruptured the principal part of the actuator same as the above in the direction parallel to an axial direction. FIG. 3 is a cross-sectional view in a direction orthogonal to a partially omitted axial direction showing a relationship between a magnetic pole portion provided on one yoke and a permanent magnet of a mover for explaining the operating principle of the above. It is sectional drawing in the direction orthogonal to the axial direction which a part of which showed the relationship between the magnetic pole part provided in one yoke of the actuator which is other embodiment, and the permanent magnet of a needle | mover. It is sectional drawing in the direction orthogonal to the axial direction which shows the relationship between the magnetic pole part provided in one yoke of the actuator which is a prior art example, and the permanent magnet of a needle | mover.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Shaft 2 Permanent magnet 3 Movable element 4 Coil 5, 5a Yoke 6 Stator 7 Magnetic pole part 8 Magnetic body 12, 12a Magnetic auxiliary member

Claims (2)

  A mover having a permanent magnet provided on a shaft via a magnetic body is wound around a stator having a coil wound in a circumferential direction so as to surround the mover and a yoke made of a cylindrical magnetic body. An actuator that is movably supported and applies a current to the coil to cause the mover to reciprocate and rotate at a predetermined angle about the shaft. The yoke is provided on both sides of the coil in the axial direction and is axially Magnetic pole portions are periodically projected in the rotational direction at different positions from the inner peripheral surfaces of the yokes on both sides toward the mover, and the permanent magnet is a shaft magnetized in a direction perpendicular to the axial direction of the shaft In the actuator which is formed in a plate shape extending in the direction and provided on the surface of the magnetic body, a magnetic auxiliary member capable of simultaneously facing the magnetic pole portions on both sides in the axial direction is provided on the stator side surface of the permanent magnet. Toss Actuator.   The magnetic auxiliary member is provided so as to cover the entire surface of the permanent magnet on the stator side, and the outer surface of the mover composed of the magnetic body and the magnetic auxiliary member and the inner surface of the magnetic pole portion are centered on the shaft. 2. The actuator according to claim 1, wherein concentric circles are formed.

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