Electric actuator
11328849 · 2022-05-10
Assignee
Inventors
Cpc classification
H02K41/03
ELECTRICITY
International classification
Abstract
The present invention comprises: a rod used as a rod-shaped member; an electroconductive polymer actuator having an electroconductive polymer that expands and contracts in a prescribed direction due to electric current; and an electromagnetic actuator having a fixed magnetic pole part in which the magnetic pole arrangement is fixed, and a variable magnetic pole part in which the magnetic pole arrangement is changed by switching of electric current, the fixed magnetic pole part and the variable magnetic pole part moving relative to each other due to the magnetic pole arrangement of the variable magnetic pole part being changed. The fixed magnetic pole part or the variable magnetic pole part is connected to the electroconductive polymer so that the relative movement direction of the fixed magnetic pole part and the variable magnetic pole part matches the expansion-contraction direction of the electroconductive polymer, and the rod is connected to the electroconductive polymer.
Claims
1. An electric actuator comprising: a rod formed of a rod-shaped member; a conductive polymer actuator having a conductive polymer that expands and contracts in a predetermined direction by an electric current, or a laminated electrostatic actuator having an electrode laminated element that expands and contracts in a predetermined direction by an electric current; and an electromagnetic force actuator having a fixed magnetic pole portion in which a magnetic pole arrangement is fixed, and a variable magnetic pole portion in which the magnetic pole arrangement is changed by switching the electric current, and in which the magnetic pole arrangement of the variable magnetic pole portion is changed so that the fixed magnetic pole portion and the variable magnetic pole portion move relative to each other, wherein any one of the fixed magnetic pole portion and the variable magnetic pole portion is connected to the conductive polymer or the electrode laminated element so that a relative movement direction thereof coincides with an expanding-contracting direction of the conductive polymer or the electrode laminated element, and the rod is connected to the conductive polymer or the electrode laminated element, and the one of the fixed magnetic pole portion and the variable magnetic pole portion which are connected to the conductive polymer or the electrode laminated element.
2. The electric actuator according to claim 1, further comprising: a casing that accommodates the rod, wherein one end side of the conductive polymer or the electrode laminated element in the expanding-contracting direction is connected to the casing, the variable magnetic pole portion is fixed to the casing, the fixed magnetic pole portion is connected to the other end side of the conductive polymer or the electrode laminated element in the expanding-contracting direction, and the rod is connected to the fixed magnetic pole portion.
3. The electric actuator according to claim 1, further comprising: an electricity supply unit that supplies electricity to the conductive polymer actuator or the laminated electrostatic actuator, and the variable magnetic pole portion; and a control unit that controls the electricity output from the electricity supply unit, wherein when the rod is moved, the control unit controls the electricity supply unit to perform expansion and contraction of the conductive polymer actuator or the laminated electrostatic actuator simultaneously with relative movement between the variable magnetic pole portion and the fixed magnetic pole portion.
4. The electric actuator according to claim 3, wherein when the movement of the rod is completed, the control unit controls the electricity supply unit to stop the relative movement between the fixed magnetic pole portion and the variable magnetic pole portion.
Description
BRIEF DESCRIPTION OF DRAWINGS
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
(15)
(16)
(17)
(18)
(19)
(20)
(21)
DESCRIPTION OF EMBODIMENTS
(22) Hereinafter, an electric actuator according to an embodiment of the present disclosure will be described with reference to the drawings.
(23) An electric actuator 1A is suitably adopted for an expansion-contraction type actuator used in operating a control surface of an aircraft, for example.
(24) For example, the control surface of the aircraft includes an aileron, an elevator, and a rudder, but is not limited to the control surfaces.
(25) In addition, as a matter of course, the electric actuator 1A can also be adopted as the expansion-contraction type actuator used for operations other than operation of the control surface of the aircraft.
(26) As illustrated in
(27) In addition, the electric actuator 1A may include an electricity supply unit 70 that supplies electricity to the conductive polymer actuator 20 and the electromagnetic force actuator 40. The electricity supply unit 70 may be an external power supply as will be described later.
(28) As illustrated in
(29) As illustrated in
(30) A connecting portion 12 is provided in a tip side (left side in
(31) An operating force is transmitted to the control surface of the aircraft from the electric actuator 1A via the connecting portion 12.
(32) A base portion side flange portion 14 is integrally formed on a base portion side (right side in
(33) The base portion side flange portion 14 has an outer diameter larger than an outer diameter of the rod 10. In addition, the base portion side flange portion 14 has an inner diameter smaller than an inner diameter of the hollow rod 10.
(34) In the rod 10, a tip side flange portion 16 is integrally formed between the connecting portion 12 and the base portion side flange portion 14 in the axial direction.
(35) The tip side flange portion 16 has the outer diameter larger than the outer diameter of the rod 10, as in the base portion side flange portion 14. In addition, the base portion side flange portion 14 has an inner diameter smaller than an inner diameter of the hollow rod 10.
(36) In this case, it is preferable that the inner diameter of the tip side flange portion 16 and the inner diameter of the base portion side flange portion 14 are the same as each other. The same applies to the outer diameter.
(37) The tip side flange portion 16 and the base portion side flange portion 14 may not necessarily be formed integrally with the rod 10. The tip side flange portion 16 and the base portion side flange portion 14 which are separated from each other may be connected and fixed to the rod 10.
(38) As illustrated in
(39) For example, the fixed magnetic pole portion 42 is a permanent magnet, and an arrangement of magnetic poles is fixed along the axial direction. Specifically, an S-pole and an N-pole are alternately arranged along the axial direction. In a case of
(40) The fixed magnetic pole portion 42 described above is one of components configuring the electromagnetic force actuator 40 illustrated in
(41) As illustrated in
(42) As illustrated in
(43) As illustrated in
(44) A plurality of electrodes 24 are provided inside the casing 80 and around the conductive polymer 22. In
(45) Each of the electrodes 24 is electrically connected to a first power supply 26 of the electricity supply unit 70 via an electric power line, and electricity is supplied from each first power supply 26.
(46) In this case, a space S2 formed between the inner peripheral surface of the casing 80 and the outer peripheral surface of the conductive polymer 22 is filled with an electrolyte 28, and an electric current supplied from the first power supply 26 to the electrode 24 can flow to the conductive polymer 22 via the electrolyte 28.
(47) As illustrated in
(48) For example, a material of the conductive polymer 22 is a semiconductor material such as polyacetylene, polyethylene, or polyester containing a conductive material such as carbon. For example, the electrolyte 28 is a potassium hydroxide solution or a lithium salt solution.
(49) As described above, one end of the conductive polymer 22 in the expanding-contracting direction is connected to the base portion 82 of the casing 80, and the other end is connected to the rod 10 (base portion side flange portion 14). In addition, the axial direction of the rod 10 and the expanding-contracting direction of the conductive polymer 22 coincide with each other.
(50) Therefore, as illustrated in
(51)
(52) As illustrated in
(53) As described above, the fixed magnetic pole portion 42 has an annular shape when viewed in the axial direction, and is fixed to the inner peripheral surface of the rod 10 located between the tip side flange portion 16 and the base portion side flange portion 14.
(54) As illustrated in
(55) As illustrated in
(56) The variable magnetic pole portion 44 is electrically connected to a second power supply 46 of the electricity supply unit 70 via an electric power line, and electricity is supplied from the second power supply 46.
(57) As illustrated in
(58) As described above, the variable magnetic pole portion 44 is inserted into the fixed magnetic pole portion 42. Accordingly, the fixed magnetic pole portion 42 and the variable magnetic pole portion 44 relatively move in a non-contact manner by changing the arrangement of the magnetic poles.
(59) In this case, as illustrated in
(60) Therefore, as illustrated in
(61) However, F2 is convenient description of the operating force, and may be a constant or a variable.
(62)
(63) As illustrated in
(64) The electricity supply unit 70 may be provided integrally with the electric actuator 1A, or may be a separate body (that is, an external power supply). In addition, the first power supply 26 and the second power supply 46 may be a single power supply. In this case, the electricity is supplied from the single power supply to the conductive polymer 22 and the variable magnetic pole portion 44 by a parallel circuit.
(65) In addition, for example, the control unit is configured to include a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and a computer-readable storage medium. Then, as an example, a series of processes for realizing various functions are stored in a storage medium in a form of a program. The CPU reads the program in the RAM, and executes information processing and arithmetic processing. In this manner, various functions are realized. The program may adopt a form in which the program is installed in advance in the ROM or another storage medium, a form in which the program is provided in a stored state in a computer-readable storage medium, or a form in which the program is delivered via wired or wireless communication means. The computer-readable storage medium is a magnetic disc, a magneto-optical disc, a CD-ROM, a DVD-ROM, or a semiconductor memory.
(66) As illustrated in
(67) In addition, the rod 10 is connected to the conductive polymer 22 and the fixed magnetic pole portion 42.
(68) Therefore, the fixed magnetic pole portion 42 is moved together with the rod 10 in the axial direction by the conductive polymer 22. When the rod 10 is moved, an operating force F1 is applied to the rod 10 from the conductive polymer 22.
(69) In addition, an operating force F2 is applied to the fixed magnetic pole portion 42 from the variable magnetic pole portion 44 connected to the casing 80. As a result, the operating force F2 is applied from the variable magnetic pole portion 44 to the rod 10 connected to the fixed magnetic pole portion 42.
(70) Therefore, the operating force F2 is applied from the variable magnetic pole portion 44 to the rod 10 to which the operating force F1 is applied from the conductive polymer 22. That is, two operating forces (operating force F1 and operating force F2) can be applied in parallel to the rod 10 from the conductive polymer 22 and the fixed magnetic pole portion 42. In other words, the operating forces can be simultaneously applied to the rod 10 by the conductive polymer actuator 20 and the electromagnetic force actuator 40.
(71)
(72) As illustrated in
(73) Next, controlling performed when expanding and contracting the electric actuator 1A, based on characteristics of the conductive polymer actuator 20 and the electromagnetic force actuator 40 will be described.
(74) The conductive polymer actuator 20 has the following characteristics.
(75) That is, the conductive polymer actuator 20 can generate the operating force greater than that of the electromagnetic force actuator 40. On the other hand, positioning accuracy or responsiveness of the conductive polymer actuator 20 is not higher than that of the electromagnetic force actuator 40.
(76) For example, as illustrated in
(77) When the length of the electric actuator 1A reaches L1, even in a case where the extension of the conductive polymer 22 is stopped at a stop position by the control unit, due to the inertial force caused by its own mass, the elastic conductive polymer 22 is gradually settled while repeating a minute expansion and contraction movement along the axial direction around the stop position. For example, as illustrated in
(78) In the above description of the conductive polymer 22, it is assumed that no operating force is applied from the electromagnetic force actuator 40. In addition, it is assumed that only the conductive polymer 22 can bear the operating force required for the movement of the rod 10.
(79) On the other hand, the electromagnetic force actuator 40 has the following characteristics.
(80) That is, the electromagnetic force actuator 40 does not generate the operating force substantially the same as that of the conductive polymer actuator 20. On the other hand, positioning accuracy or responsiveness of the electromagnetic force actuator 40 is higher than that of the electromagnetic force actuator 40.
(81) Due to the characteristics of the electromagnetic force actuator 40, the electric actuator 1A can be extended as follows.
(82) That is, when the length of the electric actuator 1A reaches L1 and the movement of the rod 10 is completed, the electromagnetic force actuator 40 stops the rod 10 at a predetermined position (position where the length of the electric actuator 1A reaches L1). In this manner, elastic deformation of the conductive polymer 22 can be suppressed.
(83) For example, as illustrated in
(84) A force generated by elastic deformation when completing the extension of the conductive polymer 22 is sufficiently smaller than the operating force F2 which can be applied by the electromagnetic force actuator 40. Therefore, the elastic deformation of the conductive polymer 22 can be easily suppressed by the electromagnetic force actuator 40.
(85) In the above description, a case where the length of the electric actuator 1A is extended has been described as an example. However, the same applies to a case where the rod 10 is moved to shorten the length of the electric actuator 1A.
(86) As described above, when the electric actuator 1A expands and contracts, it is preferable that the rod 10 is simultaneously moved by the operating forces of the conductive polymer actuator 20 and the electromagnetic force actuator 40. The reason is that a greater operating force can be ensured by the two actuators. For example, the operating force required for the movement of the rod 10 is the operating force required for operating the control surface connected to the rod 10.
(87) In addition, when the expansion and contraction of the electric actuator 1A are completed, it is preferable that the relative movement between the fixed magnetic pole portion 42 and the variable magnetic pole portion 44 of the electromagnetic force actuator 40 is stopped at a predetermined position to suppress the elastic deformation of the conductive polymer 22.
(88) According to the electric actuator 1A in the present embodiment, the following advantageous effects are achieved.
(89) The resultant force of the operating force F1 of the conductive polymer actuator 20 and the operating force F2 of the electromagnetic force actuator 40 is applied to the rod 10.
(90) Therefore, the two actuators can sufficiently bear the operating forces required for the movement of the rod 10. Accordingly, electric power required for each actuator can be suppressed, and the actuator can be miniaturized.
(91) In this case, the conductive polymer actuator 20 has a greater expanding-contracting force (that is, the operating force F1 for moving the rod 10) than that of the electromagnetic force actuator 40. However, positioning accuracy or responsiveness is not high. In contrast, the electromagnetic force actuator 40 has a smaller force applied between the variable magnetic pole portion 44 and the fixed magnetic pole portion 42 (that is, the operating force F2 for moving the rod 10) than that of the conductive polymer actuator 20. However, the positioning accuracy or the responsiveness is satisfactory.
(92) Therefore, in the operating force required for the movement of the rod 10 (that is, expansion and contraction of the electric actuator 1A), the conductive polymer actuator 20 is configured to bear most of the operating force, and the electromagnetic force actuator 40 is configured to bear the remaining operating force. In this manner, when the rod 10 is moved, the required operating force can be ensured by the two actuators. In addition, when the movement of the rod 10 is completed, the electromagnetic force actuator 40 can have high responsiveness, and can perform highly accurate positioning.
(93) In addition, in a case where the variable magnetic pole portion 44 is fixed to the casing 80, it is possible to avoid the movement (movement due to the expansion and contraction of the conductive polymer 22) of the variable magnetic pole portion 44 having a more complicated structure than that of the fixed magnetic pole portion 42. Therefore, a simplified structure can be realized.
(94) The fixed magnetic pole portion 42 and the variable magnetic pole portion 44 may be replaced with each other. For example, the variable magnetic pole portion 44 may be fixed to the rod 10, and the fixed magnetic pole portion 42 may be fixed to the casing 80.
Modification Example
(95) As illustrated in
(96) The laminated electrostatic actuator 30 is configured to arrange a plurality of rows formed by aligning a plurality of electrode laminated elements 32 in the axial direction.
(97) One electrode laminated element 32 is an element in which a plurality of electrodes are laminated in a predetermined direction, and expands and contracts in the predetermined direction (laminating direction) by applying a voltage from the first power supply 26.
(98) For example, as illustrated in
(99) In this case, as the laminated electrostatic actuator 30, an appropriate number of the electrode laminated elements 32 are aligned in the axial direction, and each of the electrode laminated elements 32 is extended by dL in a predetermined direction. In this manner, as illustrated in
(100) In this manner, the laminated electrostatic actuator 30 can be adopted instead of the conductive polymer actuator 20.
REFERENCE SIGNS LIST
(101) 1A, 1B: electric actuator 10: rod 12: connecting portion 14: base portion side flange portion 16: tip side flange portion 20: conductive polymer actuator 22: conductive polymer 24: electrode 26: first power supply 28: electrolyte 30: laminated electrostatic actuator 32: electrode laminated element 40: electromagnetic force actuator 42: fixed magnetic pole portion 44: variable magnetic pole portion 46: second power supply 70: electricity supply unit 80: casing 82: base portion S1: space S2: space X: axis