JP2007037273A - Vibratory linear actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibratory linear actuator wherein enhancement of thrust by reduction of magnetic reluctance can be accomplished without incurring increase in size. <P>SOLUTION: The vibratory linear actuator is constructed of: a stator 1 having winding 12; and a moving member 2, provided with permanent magnets 22, that is opposed to the stator 1 with a gap in-between and is supported so that it can reciprocate. The winding 12 of the stator 1 is wound on a part of a core 11 having multiple magnetic pole teeth 12. In the moving member 2, the permanent magnets 22 are magnetized in the direction in which they are opposed to the stator 1 and have two or more magnetic poles so arranged that unlike poles are alternately lined in the direction of reciprocation. The magnetic poles of the permanent magnets 22 on the opposite side to the gap are magnetically connected through a yoke 21. The yoke 21 of the moving element 2 has protrusions 23 that are protruded toward the stator 1 at both ends of its reciprocation and/or between unlike poles of the permanent magnets 22 lined in the direction of reciprocation. Part of magnetic flux passes through the protrusions of the yoke, and the magnetic efficiency of the entire magnetic circuit is thereby enhanced. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration type linear actuator used as a driving member such as a reciprocating electric shaver.

  An example of a conventional vibration type linear actuator is shown in FIG. The stator 1 is composed of an E-shaped core 11 formed by laminating a sintered body of magnetic material or an iron plate of magnetic material, and a winding 12 wound around a magnetic pole tooth 13 at the center of the core 11. The movable element 2 facing the stator 1 through a gap arranges the permanent magnets 22 whose magnetization direction is the opposite direction to the stator 1 in the reciprocating direction and on the opposite side of the stator 1. It is composed of a flat yoke 21 that magnetically connects between the magnetic poles. When an alternating current is passed through the winding 12 of the stator 1, the mover 2 reciprocates.

  In this configuration, since only the permanent magnet 22 is opposed to the magnetic pole teeth 13 through the gap, the magnetic flux generated by the excitation of the winding 12 takes a path through both the gap and the permanent magnet 22. Therefore, since the magnetic resistance is large and the amount of generated magnetic flux is small, the thrust generated when the winding 12 is energized cannot be increased so much. To increase the thrust, the permanent magnet 22 or There is only a method for increasing the volume such as increasing the thickness of the core 11 or increasing the cross-sectional area of the winding 12, and it is difficult to reduce the size.

Patent Document 1 discloses that an eddy current loss is reduced by interposing an insulating thin plate 28 between permanent magnets 22, but it is not a measure for thrust.
JP 2000-253640 A

  The present invention has been invented in view of the above-described conventional problems, and an object of the present invention is to provide a vibration type linear actuator capable of improving thrust by reducing magnetic resistance without causing an increase in size. Is.

  In order to solve the above-described problems, the present invention includes a stator having a winding, and a mover that includes a permanent magnet and is opposed to the stator via a gap and is supported so as to be able to reciprocate. The stator has the winding wound around a part of a core having a plurality of magnetic pole teeth, and the mover is magnetized in a direction opposite to the stator and has the reciprocating motion. This is a vibration type linear actuator in which a stator of a permanent magnet having two or more magnetic poles with different poles alternately arranged in a direction and magnetic poles opposite to each other are magnetically connected by a yoke. It has a feature in that there are protrusions protruding toward the stator side between both ends in the reciprocating direction and / or different poles arranged in the reciprocating direction of the permanent magnet. The magnetic efficiency of the entire magnetic circuit is improved by allowing a part of the magnetic flux to pass through the protrusions of the yoke.

  At this time, the yoke of the mover has the same number of protrusions as the number of magnetic pole teeth of the stator, and if the stator magnetic pole teeth and the protrusions are opposed to each other at 1: 1, the coil is energized. Since all the magnetic fluxes generated through the magnetic pole teeth and passing through the magnetic pole teeth pass through the protrusions of the yoke of the mover, a magnetic path having a small magnetic resistance can be obtained for any magnetic pole teeth.

  In particular, the stator is formed by winding a coil around the central magnetic pole teeth of an E-shaped core having three magnetic pole teeth, and the yoke includes three protrusions arranged in the reciprocating direction. If permanent magnets are arranged between them, only one winding is required, and the number of parts is reduced.

  The yoke of the mover may have a smaller number of protrusions than the number of magnetic pole teeth that the stator has. In particular, the number of permanent magnets can be reduced when the protrusions located between the permanent magnets are eliminated.

  It is most preferable from the viewpoint of reducing the magnetic resistance that the tip surface of the protrusion of the yoke of the mover and the gap side surface of the permanent magnet are the same surface. Even if the gap side surface is not reached, a path having a smaller magnetic resistance than the conventional one can be obtained, so that the thrust can also be improved.

  It is also preferable that the projecting side surface of the mover yoke and the side surface where the permanent magnet is joined are inclined surfaces. The magnetic resistance can be reduced by reducing or eliminating the magnetic saturation, and the thrust can be further improved.

  According to the present invention, the magnetic resistance is reduced due to the presence of the protrusion provided on the yoke of the mover, and the magnetic saturation is reduced and the magnetic flux is transmitted obliquely with respect to the vibration direction from the end of the permanent magnet toward the stator. The increase in thrust can be obtained without causing an increase in size.

  Hereinafter, the present invention will be described based on an embodiment shown in the accompanying drawings. In FIG. 1, a stator 1 includes a core 11 and a winding 12 made of a magnetic material. The winding 12 is wound around the central magnetic pole teeth 13. A drive circuit D that applies an alternating current according to the position and speed of the mover 2 is connected to the winding 12.

  The mover 2 that is opposed to the stator 1 through a gap and is reciprocally supported in a direction in which the magnetic pole teeth 13 of the stator 1 are arranged by means of a leaf spring (not shown) is provided with two permanent magnets. The two permanent magnets 22, 22, which are composed of 22, 22 and the yoke 21 and are arranged at intervals in the reciprocating direction, are both magnetized in the direction facing the stator 1, The permanent magnets 22 and 22 have different magnetic poles on the stator 1 side. And the yoke 21 which carries out the magnetic connection of the surface on the opposite side to the stator 1 of the two permanent magnets 22 and 22 protrudes toward the stator 1 side at both ends and the center in the reciprocating direction, and the tip end surface is The permanent magnet 22 is provided with a projection 23 that is flush with the surface of the stator 1 on the permanent magnet 22, and the permanent magnet 22 is positioned between the projections 23 and 23 in the reciprocating direction.

  In this case, when an alternating current corresponding to the position, speed, etc. of the mover 2 is applied from the drive circuit D to the winding 12, the mover 2 reciprocates in the direction indicated by the arrow.

  In the above embodiment, the yoke 21 is provided with three protrusions 23 corresponding to the three magnetic pole teeth 13 on the stator 1 side in a 1: 1 ratio, but as shown in FIG. 23, 23 and two permanent magnets 22 and 22 are arranged on both protrusions 23 and 23, or the protrusion 23 is provided only at the center of the yoke 21 and the permanent magnets 22 on both sides of the central protrusion 23. , 22 may be located. Further, as shown in FIG. 3, the tip of the protrusion 23 may not reach the surface of the permanent magnet 22 on the stator 1 side. Further, the protrusion 23 does not have to have a constant width. In this case, the width on the base end side is made wider than that on the tip end side, and the joint surface between the side face of the protrusion 23 and the permanent magnet 22 is shown in FIG. As described above, it is preferable to have an inclined surface.

  Here, of the three protrusions 23 in the embodiment shown in FIG. 1, the width of the central protrusion 23 located between the permanent magnets 22 and 22 is opposed to the stator 1 as shown in FIG. 6 (a). On the surface, the width a of the magnetic pole teeth 13 at the center portion of the stator 1 is set to 1/3, and the outer end portions of the two permanent magnets 22 and 22 are substantially aligned with the center portions of the magnetic pole teeth 13 and 13 on both sides. In addition, FIG. 6B shows a magnetic flux diagram at the time of energization of the yoke 21 in which the length in the reciprocating direction coincides with the length of the core 11 of the stator 1. FIG. 7 (a) shows a conventional magnetic flux diagram (when the stator 1 is the same as that shown in FIG. 6 (a) and the permanent magnet 22 is lengthened by the width of the projection 23 when energized. 7 (b), the magnetic flux generated by energizing the winding 12 passes through the projections 23 of the yoke 21 of the mover 2 from each magnetic pole tooth 13 of the stator 1, and the yoke 21 on the back side of the permanent magnet 22. Therefore, it is expected that the magnetic efficiency is improved by reducing the magnetic resistance.

  Further, the magnetic flux outside the permanent magnet 22 draws a path that passes through the protrusion 23 provided on the yoke 21 of the mover 2. For this reason, there are many cases where the magnetic flux takes a short-circuit path that crosses the gap in the traveling direction and does not pass through the stator 1. Further, since the distance between the permanent magnets 22 is increased at the central protrusion 23, the magnetic flux that is transmitted obliquely with respect to the vibration direction from the end of the permanent magnets 22 having a large influence on the generated thrust toward the stator 1 is increased. .

  Further, the saturation of the central portion of the movable element 2 is canceled by the path outside the movable element 2 of the magnetic flux, the direction of the transmitted magnetic flux by the central projection 23 is changed, and the short circuit path of the outer magnetic flux and the generated magnetic flux by the winding 12 are changed. Both increase with decreasing magnetic resistance. These interactions increase the thrust.

  Further, the displacement of the mover 2 changes the facing area of the yoke 21 of the mover 2 and the core 11 of the stator 1 to change the inductance of the magnetic path, and accordingly, the magnetic energy stored in the gap changes. Reluctance power can be obtained. As a result, the total thrust can be improved by the increase in magnetic flux and the reluctance force due to the decrease in magnetic resistance and the elimination of saturation.

  FIG. 5 shows a simulation result of the generated thrust. In the figure, B is the example shown in FIG. 1, B is the example shown in FIG. 2, C is the example shown in FIG. 3, D is the example shown in FIG. 4, and E is the conventional example shown in FIG. An example case is shown. In each configuration, the overall width and the ratio in the height direction of each element are the same, and the dimension of the permanent magnet 22 in the reciprocating direction is the shortest in the case of FIG. In the simulation, the displacement at the position where the centers of the stator 1 and the mover 2 coincide with each other is set to 0, and the displacement of the mover 2 and the change in thrust are obtained. According to this simulation result, it was found that the thrust provided on the yoke 21 of the mover 2 increased by about 20% compared to the one using the flat yoke 21.

  Incidentally, in the case shown in FIG. 2 (b in FIG. 5), since there is no central projection 23, the effect of reducing the magnetic resistance of the magnetic circuit passing through the central magnetic pole teeth 13 cannot be obtained. In order to achieve the effect of improving the thrust by reducing the magnetic resistance of the magnetic path, the thrust increase rate is small compared to the conventional configuration, but it is effective for improving the thrust. Further, in this case, as compared with the example shown in FIG. 1, it is not necessary to separate the permanent magnets 22, 22, so that one permanent magnet 22 can be used in manufacturing the mover 2. .

  In the case shown in FIG. 3 (c in FIG. 5), since the projection 23 provided in the center does not reach the gap surface, the magnetic resistance of the magnetic circuit passing through the magnetic pole teeth 13 in the center is shown in FIG. Although it is larger than the above, there is an effect of reducing the magnetoresistance.

  Further, in the case shown in FIG. 4 (d in FIG. 5), the height of the mover 2 is not changed compared with that shown in FIG. 1, but both side surfaces of the projection 23 at the center of the yoke 21 are inclined surfaces. And the thickness of the yoke 21 increases toward the center (the thickness of the permanent magnet 22 decreases toward the center). Since the transmitted magnetic flux is further increased due to a decrease in magnetic resistance due to elimination of magnetic saturation, a higher thrust can be obtained.

  In the above examples, the widths of the three magnetic pole teeth 13 are all the same, but the width may be changed for each magnetic pole tooth 13 in accordance with the usage pattern. Moreover, although what wound the coil | winding 12 to the center magnetic pole tooth | gear 13 was shown, what wound the coil | winding 12 also to the other magnetic pole tooth | gear 13 may be used.

It is a schematic sectional drawing of an example of embodiment of this invention. It is a schematic sectional drawing of another example. Furthermore, it is a schematic sectional drawing of another example. It is a schematic sectional drawing of another example. It is a characteristic view which shows the thrust simulation result in each example. (a) is explanatory drawing of an example, (b) is explanatory drawing of a magnetic flux line same as the above. (b) is explanatory drawing of a prior art example, (b) is explanatory drawing of a magnetic flux line same as the above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stator 2 Movable element 11 Core 12 Winding 13 Magnetic pole tooth 21 Yoke 22 Permanent magnet 23 Protrusion

Claims (6)

  A stator having windings, and a mover that has a permanent magnet and is opposed to the stator through a gap and is supported so as to be reciprocally movable. The stator has a plurality of magnetic pole teeth. The winding is wound around a part of the core having, and the mover is magnetized in a direction facing the stator and has two or more poles in which different polarities are alternately arranged in the reciprocating direction. A vibration type linear actuator in which magnetic poles opposite to a stator of a permanent magnet having magnetic poles are magnetically connected by a yoke, wherein the yoke of the mover has both ends in its reciprocating direction and / or a permanent magnet. A vibration type linear actuator characterized by having a protrusion protruding toward the stator side between different poles arranged in the reciprocating direction.   2. The vibration according to claim 1, wherein the yoke of the mover includes a number of protrusions equal to the number of magnetic pole teeth of the stator, and the magnetic pole teeth and protrusions of the stator face each other at a ratio of 1: 1. Type linear actuator.   The stator is obtained by winding a coil around the central magnetic pole teeth of an E-shaped core having three magnetic pole teeth, and the mover includes three protrusions arranged in the reciprocating direction in the yoke and between the protrusions. The vibration type linear actuator according to claim 2, wherein permanent magnets are respectively arranged on the vibration type linear actuator.   2. The vibration type linear actuator according to claim 1, wherein the yoke of the mover includes a number of protrusions smaller than the number of magnetic pole teeth of the stator.   5. The vibration type linear device according to claim 1, wherein a tip end surface of the protrusion of the yoke of the mover and a surface on the gap side of the permanent magnet are the same surface. Actuator.   The vibration type linear actuator according to any one of claims 1 to 5, wherein a joint side surface between the projecting side surface of the mover yoke and the permanent magnet is an inclined surface.

Images