Bidirectional Actuator

Abstract

To provide a bidirectional actuator capable of regulating a stroke width of a movable element at the time of operation and holding the movable element at the time of non-operation.SOLUTION: A bidirectional actuator (actuator 100) has a coil 110 wound like a cylindrical shape, a fixed yoke 120 covering the coil 110, and a movable element 130 moving in both directions in an axial direction of the coil 110 inside of the fixed yoke 120. On an inner peripheral surface of the fixed yoke 120, a slit 122 in a circumferential direction is formed. In the movable element 130, two magnets (upper side magnet 132a, lower side magnet 132b) whose magnetic poles are opposite to each other are arranged in the axial direction. A movable yoke 134 projecting in a flange shape is placed between the two magnets. The movable yoke 134 is placed between the fixed yoke 120 and the slit 122.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a bidirectional actuator capable of actively moving a shaft in both directions. [Background technology]

[0002] An example of a typical actuator using a coil and a movable core is the linear actuator disclosed in Patent Document 1. The linear actuator in Patent Document 1 has a fixed body equipped with a coil wound in a ring shape, a first movable body side yoke whose circumferential surface faces the coil on the inside or outside of the coil, and a movable body equipped with a pair of magnets stacked on both sides of the first movable body side yoke in the axial direction with the same poles facing the first movable body side yoke.

[0003] In the linear actuator of Patent Document 1, the movable body is driven in the axial direction by energizing the coil. According to the configuration of Patent Document 1, since it is sufficient to magnetize the magnet in the axial direction, unlike magnetizing the magnet in the radial direction, magnetization is easy even when the actuator is miniaturized, and it is suitable for mass production. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-158135 A Summary of the Invention [Problem to be solved by the invention]

[0005] In a bidirectional actuator, it is necessary to control the stroke width of the movable body when it is in operation. In Patent Document 1, a bearing plate (bearing member) is fixed to the openings on both sides in the axial direction of the fixed body. As a result, the stroke width of the movable body when it is in operation is restricted by the bearing plate (bearing member). However, with the configuration of Patent Document 1, it is not possible to hold the movable body when it is not in operation. For this reason, it is not possible to restrict the position of the movable body when it is not in operation, and the behavior of the movable body when it is not in operation becomes unstable.

[0006] An object of the present invention is to provide a bidirectional actuator capable of regulating the stroke width of a mover when in operation and holding the mover when not in operation. [Means for solving the problem]

[0007] In order to solve the above problems, a representative configuration of a bidirectional actuator according to the present invention comprises a cylindrically wound coil, a fixed yoke covering the coil, and a movable element that moves in both directions inside the fixed yoke in the axial direction of the coil, the inner surface of the fixed yoke having a circumferential slit formed therein, the movable element having two magnets with opposing magnetic poles arranged in the axial direction, a movable yoke protruding like a flange arranged between the two magnets, and the movable yoke arranged between the slits of the fixed yoke.

[0008] According to the above configuration, the movable element is disposed between the two magnets, with the movable yoke protruding like a flange, between the slits of the fixed yoke. As a result, when the bidirectional actuator is in operation, the movable element moves within the range of the slits of the fixed yoke. This makes it possible to suitably regulate the stroke width of the movable element when in operation. And, when the actuator is not in operation, the movable element is attracted to and held at one of the two ends of the slits of the fixed yoke. This makes it possible to stabilize the behavior when the actuator is not in operation.

[0009] It is preferable to further provide a second movable yoke on the outer side of each of the two magnets with the flange-shaped protruding movable yoke as the center. With this configuration, the air gap in the magnetic path can be reduced, thereby enhancing the above-mentioned effects. Effect of the Invention

[0010] According to the present invention, it is possible to provide a bidirectional actuator capable of regulating the stroke width of the mover when in operation and holding the mover when not in operation. [Brief description of the drawings]

[0011] [Figure 1] 1 is an overall configuration diagram of a bidirectional actuator according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram illustrating an actuator in an excited state (during operation). [Diagram 3] 11A and 11B are diagrams illustrating another example of the bidirectional actuator of the present embodiment. [Figure 4] 11A and 11B are diagrams illustrating another example of the bidirectional actuator of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. The dimensions, materials, and other specific values ​​shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are given the same reference numerals to avoid repeated explanations, and elements not directly related to the present invention are not shown.

[0013] 1 is an overall configuration diagram of a bidirectional actuator according to this embodiment (hereinafter referred to as actuator 100), showing a state in which both coils 110 are not excited, i.e., the actuator 100 is not in operation. There is no distinction between up, down, left, and right in the actuator 100 according to this embodiment, and the terms "up, down, left, and right" used below simply refer to up, down, left, and right on the drawing.

[0014] 1 has a cylindrically wound coil 110. The coil 110 is covered by a fixed yoke 120. The fixed yoke 120 is made of a magnetic material and forms a magnetic circuit.

[0015] A mover 130 that moves in both directions in the axial direction of the coil 110 is disposed inside the fixed yoke 120. The mover 130 has two magnets (hereinafter referred to as upper magnet 132a and lower magnet 132b) with opposing magnetic poles disposed in the axial direction, and a movable yoke 134 that protrudes in a flange shape is disposed between the two magnets. In this embodiment, the opposing magnetic poles of the upper magnet 132a and the lower magnet 132b are exemplified as an N pole and an opposite magnetic pole as an S pole.

[0016] A circumferential slit 122 is formed in the inner peripheral surface of the fixed yoke 120 near the center position of the coil 110. A flange portion 136 of the movable yoke 134 is disposed so as to be inserted between the slits 122 of the fixed yoke. In addition, the flange portion 136 of the movable yoke 134 is sandwiched between the N poles of the upper magnet 132a and the lower magnet 132b, and therefore serves as an N pole.

[0017] 1 illustrates a non-excited state (non-operating state) in which the flange portion 136 of the movable yoke 134 is attracted to and held by the fixed yoke 120 above the slit 122. In the actuator 100 in the non-excited state illustrated in FIG. 1, the magnetic flux M1 of the upper magnet 132a flows from the N pole through the movable yoke 134 and a part of the fixed yoke 120 to the S pole of the upper magnet 132a. The magnetic flux M2 of the lower magnet 132b flows from the N pole to the S pole of the lower magnet 132b, making a large circle around the flange portion 136 and the fixed yoke 120.

[0018] Fig. 2 is a diagram illustrating the actuator 100 in an excited state (operating). Fig. 2(a) is a diagram illustrating the actuator 100 in a state where a current is flowing (excited state). Fig. 2(b) shows the actuator 100 in a state where a current is flowing in the opposite direction to that in Fig. 2(a) (excited state).

[0019] When a current is applied to the coil 110 shown in FIG. 2(a), the magnetic flux M1 of the upper magnet 132a and the magnetic flux M2 of the lower magnet 132b flow in the same direction as in FIG. 1. When a current flows, the coil 110 is excited, and a magnetic flux M0 flows through the fixed yoke 120. At this time, the upper end 124 of the slit 122 of the fixed yoke 120 becomes an S pole, and the lower end 126 of the slit becomes an N pole. Then, the flange portion 136 of the mover 130 repels the lower end 126 of the slit 122 and is attracted to the upper end 124 of the slit 122. When the current is stopped in the state shown in FIG. 2(a), the mover 130 is attracted to the fixed yoke 120 at the end 124 and held thereon.

[0020] 2(b), when a current is passed through the coil 110 in the opposite direction, the coil 110 is excited in the opposite direction, and the magnetic flux M0 flowing through the fixed yoke 120 is reversed. At this time, the upper end 124 of the slit 122 of the fixed yoke 120 becomes the N pole, and the lower end 126 of the slit 122 becomes the S pole. Then, the flange portion 136 of the mover 130 repels the upper end 124 of the slit 122, and an attractive force is generated between the flange portion 136 and the lower end 126 of the slit 122, so that the mover 130 moves downward.

[0021] When the mover 130 moves downward, the magnetic flux M1 of the upper magnet 132a flows from the N pole to the S pole of the upper magnet 132a, around the flange portion 136 and the fixed yoke 120. The magnetic flux M2 of the lower magnet 132b flows from the N pole to the S pole of the lower magnet 132b, through the mover 134 and a part of the fixed yoke 120. Then, when the current is stopped in the state shown in FIG. 2(b), the mover 130 is attracted to and held by the fixed yoke 120 at the end portion 126.

[0022] As described above, in the actuator 100 of this embodiment, the flange portion 136 of the movable yoke 134 is disposed between the slits 122 of the fixed yoke 120, so that the mover 130 moves within the range of the slits 122 of the fixed yoke 120. Therefore, it is possible to suitably regulate the stroke width of the mover 130 during operation.

[0023] As described above, when the coil 110 is in a non-excited state, the mover 130 is attracted to and held by the fixed yoke 120 at the end of the fixed yoke 120 that was closer when the coil 110 was excited. Therefore, the position of the mover 130 can be maintained even when the coil 110 is not in operation.

[0024] 3 is a diagram illustrating another example of the bidirectional actuator of this embodiment. The bidirectional actuator shown in FIG. 3 (hereinafter referred to as actuator 200) has inclined surfaces 224 above and below slit 122 of fixed yoke 220. Meanwhile, mover 230 has inclined surfaces 238 above and below flange portion 136.

[0025] As shown in FIG. 1, when the end faces of slit 122 are flat and the upper and lower faces of flange portion 136 of movable member 130 are also flat, the adhesive force increases steeply inversely proportional to the square of the distance (spacing) between them.

[0026] However, by making the inclined surfaces 224 and 238 face each other as shown in Fig. 3, the gap (distance) between the mover 230 and the fixed yoke 220 can be made small from a position where the mover 230 is far from the top dead center or bottom dead center. In other words, the magnetic attraction force between the mover 230 and the fixed yoke 220 can be gradually strengthened. This makes it possible to generate a desired attraction force within the stroke range of the mover 230, and stabilize the behavior. In addition, since the magnetic force can be suppressed, it is possible to reduce the impact and noise when the flange portion 136 hits the fixed yoke 220.

[0027] Fig. 4 is a diagram illustrating another example of the bidirectional actuator of this embodiment. The bidirectional actuator (hereinafter referred to as actuator 300) shown in Fig. 3 has two second movable yokes 302a and 302b arranged adjacent to the surfaces of two magnets (upper magnet 132a and lower magnet 132b) opposite to the surfaces facing the movable yoke 134. This configuration makes it possible to reduce the air gap in the magnetic path and enhance the above-mentioned effects.

[0028] Although the preferred embodiment of the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such an example. It is clear that a person skilled in the art can think of various modified or altered examples within the scope of the claims, and it is understood that such examples also naturally belong to the technical scope of the present invention. [Industrial Applicability]

[0029] The present invention can be used as an actuator that can actively move a shaft in both directions. [Explanation of symbols]

[0030] M0...magnetic flux, M1...magnetic flux, M2...magnetic flux, 100...actuator, 110...coil, 120...fixed yoke, 122...slit, 124...end, 126...end, 130...movable element, 132a...upper magnet, 132b...lower magnet, 134...movable yoke, 136...flange portion, 200...actuator, 220...fixed yoke, 224...inclined surface, 230...movable element, 238...inclined surface, 300...actuator, 302a, 302b...second movable yoke

Claims

[Claim 1] A cylindrically wound coil; A fixed yoke that covers the coil; a mover that moves in both directions in the axial direction of the coil inside the fixed yoke, The fixed yoke has an inner peripheral surface formed with a circumferential slit, The mover is Two magnets with opposing poles are arranged in the axial direction. A movable yoke having a flange portion protruding in a flange shape is disposed between the two magnets, The flange portion of the movable yoke is disposed so as to be inserted between the slits of the fixed yoke, A bidirectional actuator, characterized in that, when the coil is in a non-excited state, a flange portion of the movable yoke is attracted to and held by the fixed yoke at an upper or lower portion of a slit.

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