Electrostatic motor

Abstract

To provide an electrostatic motor 1 having a simple structure and capable of being reduced in weight.SOLUTION: In an electrostatic motor 1, all polarities of stator electrodes 50a to 50h, 51a to 51h, 52a to 52h and 53a to 53h are set to a negative polarity. Therefore, creeping discharge does not occur in a stator 10. All polarities of rotor electrode 60a to 60h, 61a to 61h and 62a to 62h are sequentially switched from one of the positive and negative polarities to the other. Therefore, creeping discharge does not occur also in a rotor 20. Thus, an electrical insulating member can be eliminated in the stator 10 and the rotor 20.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to electrostatic motors. [Background technology]

[0002] Conventionally, an electrostatic motor has been proposed that includes a stator having a plurality of first stator electrodes and a plurality of second stator electrodes, and a rotor that is disposed in the axial direction relative to the stator and has a plurality of rotor electrodes (see, for example, Patent Document 1). The plurality of first stator electrodes and the plurality of second stator electrodes are alternately arranged one by one in the circumferential direction around the axis.

[0003] The plurality of rotor electrodes are respectively arranged in a radial direction about the axis relative to the plurality of first stator electrodes and the plurality of second stator electrodes. A positive voltage is applied to the plurality of first stator electrodes, and a negative voltage is applied to the plurality of second stator electrodes. When the rotor electrode is positioned on the other side of the first stator electrodes in the direction of rotation, a negative voltage is applied to the rotor electrode. As a result, a torque is generated in the rotor electrode that rotates the rotor in one direction of rotation due to an attractive force caused by an electrostatic force with respect to the first stator electrode.

[0004] Then, when the rotor electrode is positioned on one side of the first stator electrode in the direction of rotation, a positive voltage is applied to the rotor electrode. This causes a torque to rotate the rotor in one direction of rotation due to the electrostatic reaction force with the first stator electrode and the electrostatic attraction force with the second stator electrode. In this way, by switching the voltage applied to the rotor electrode from one side to the other, a rotational torque is generated that rotates the rotor electrode and, ultimately, the rotor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-48557 Summary of the Invention [Problem to be solved by the invention]

[0006] In the electrostatic motor, the voltage applied to the rotor electrodes is switched from one of a positive voltage and a negative voltage to the other, thereby generating a rotational torque that rotates the rotor. However, a positive voltage is applied to the first stator electrodes, and a negative voltage is applied to the second stator electrodes. Therefore, in order to increase the output of the electrostatic motor, it is necessary to increase the voltage difference between the first stator electrodes and the second stator electrodes.

[0007] In this case, it becomes difficult to ensure electrical insulation between the first and second stator electrodes. Therefore, to prevent creeping discharges between the first and second stator electrodes, it becomes necessary to place an electrical insulating member between the first and second stator electrodes. This increases the weight of the electrostatic motor. In view of the above, an object of the present disclosure is to provide an electrostatic motor that is lightweight. [Means for solving the problem]

[0008] According to one aspect of the present disclosure, an electrostatic motor comprises: a stator (10) having a plurality of stator electrodes (50, 50a to 50h, 51a to 51h, 52a to 52h, 53a to 53h) arranged at equal intervals in a circumferential direction around an axis (S); a rotor (20) having a plurality of rotor electrodes (60, 60a to 60h, 61a to 61h, 62a to 62h) arranged at equal intervals in a circumferential direction around an axis, and configured to be rotatable relative to a stator in one direction of a rotation (Ka) around the axis; In the case where one of the plurality of stator electrodes and the plurality of rotor electrodes is defined as a plurality of one-side electrodes, and the other of the stator electrodes and the rotor electrodes other than the plurality of one-side electrodes is defined as a plurality of other-side electrodes, and a control unit (2) that sets the polarity of the plurality of one-side electrodes to either positive or negative, and sequentially switches the polarity of the plurality of other-side electrodes from either positive or negative to the other, thereby generating a rotational torque in the rotor that rotates the rotor in one direction of rotation by an attractive force due to electrostatic force generated between the plurality of rotor electrodes and the plurality of stator electrodes.

[0009] Therefore, the polarities of the plurality of first-side electrodes are all set to either positive or negative, and the polarities of the plurality of second-side electrodes are all sequentially switched from one of positive and negative to the other. This makes it possible to suppress creeping discharge in the plurality of stator electrodes. This makes it possible to suppress creeping discharge in the plurality of rotor electrodes. As a result, no electrical insulating member is provided in each of the plurality of stator electrodes and the plurality of rotor electrodes. Therefore, by eliminating the electrical insulating member in each of the plurality of stator electrodes and the plurality of rotor electrodes, it is possible to provide an electrostatic motor that is lightweight. The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing the overall configuration of an electrostatic motor according to a first embodiment of the present disclosure, and is a perspective view for assisting in the description of the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 2] FIG. 2 is a cross-sectional view of the electrostatic motor according to the first embodiment of FIG. 1, taken along an imaginary plane including an axis, and is a diagram for assisting in explaining the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 3] FIG. 2 is a top view of the electrostatic motor according to the first embodiment of FIG. 1, and is a diagram for assisting in the description of the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 4]FIG. 2 is an electric circuit diagram showing the electric circuit configuration of an inverter circuit for operating the rotor of the electrostatic motor in the first embodiment of FIG. [Figure 5] 2 is a diagram showing the relative positions of rotor electrodes and stator electrodes in the electrostatic motor according to the first embodiment of FIG. 1, the polarities of the rotor electrodes and stator electrodes, the voltages applied to the rotor electrodes, and the rotational torque generated in the rotor. FIG. [Figure 6] 1. FIG. 4 is a diagram showing the relationship between time and electrical angle, the relationship between time and voltage applied to rotor electrodes, and the relationship between time and rotational torque generated in the rotor electrodes in the electrostatic motor according to the first embodiment of FIG. [Figure 7] FIG. 10 is a perspective view showing the overall configuration of an electrostatic motor in a comparative example, and is a perspective view for assisting in explaining the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 8] 8A and 8B are diagrams showing the relationship between time and electrical angle, the relationship between voltage applied to rotor electrodes and time, and the relationship between rotational torque generated in the rotor electrodes and time in the electrostatic motor in the comparative example of FIG. 7. [Figure 9] 1. FIG. 4 is a diagram showing the relationship between the distance between the theta electrodes and rotor electrodes, the electrostatic force generated in the rotor, and the position in the direction of rotation, used to explain optimization of the electrode configuration of the electrostatic motor in the first embodiment of FIG. [Figure 10] 2 is a diagram showing the relationship between rotational torque and the number of poles in the electrostatic motor according to the first embodiment of FIG. 1. FIG. [Figure 11] FIG. 10 is an electric circuit diagram showing the electric circuit configuration of an inverter circuit for operating a rotor of an electrostatic motor according to a second embodiment of the present disclosure. [Figure 12] 12A to 12C are diagrams showing the relationship between time and electrical angle, the relationship between time and voltage applied to rotor electrodes, and the relationship between time and rotational torque generated in the rotor electrodes in the electrostatic motor according to the second embodiment of FIG. [Figure 13] FIG. 10 is an electric circuit diagram showing the electric circuit configuration of an inverter circuit for operating a rotor of an electrostatic motor according to a third embodiment of the present disclosure. [Figure 14]14A to 14C are diagrams showing the relationship between time and electrical angle, the relationship between time and voltage applied to the rotor electrodes, and the relationship between time and rotational torque generated in the rotor electrodes in the electrostatic motor according to the third embodiment of FIG. 13. [Figure 15] FIG. 10 is an electric circuit diagram showing the electric circuit configuration of an inverter circuit for operating a rotor of an electrostatic motor according to a fourth embodiment of the present disclosure. [Figure 16] 16A and 16B are diagrams showing the relationship between time and electrical angle, the relationship between voltage applied to rotor electrodes and time, and the relationship between rotational torque generated in the rotor electrodes and time in the electrostatic motor according to the fourth embodiment of FIG. 15. [Figure 17] FIG. 11 is a cross-sectional view taken along a virtual plane including an axis of an electrostatic motor according to a fifth embodiment of the present disclosure, and is a view for assisting in explaining the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 18] FIG. 18 is a diagram showing the arrangement relationship of a plurality of stator electrodes and a plurality of rotor electrodes in the electrostatic motor according to the fifth embodiment of FIG. 17, and is a cross-sectional view of the plurality of stator electrodes and the plurality of rotor electrodes cut along a virtual plane perpendicular to the axis. [Figure 19] FIG. 13 is a cross-sectional view taken along a virtual plane including an axis of an electrostatic motor according to a sixth embodiment of the present disclosure, and is a view for assisting in explaining the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 20] FIG. 13 is a perspective view showing the overall configuration of an electrostatic motor according to a seventh embodiment of the present disclosure, and is a perspective view for assisting in the description of the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 21] FIG. 21 is a perspective view for assisting in the description of the configuration of the stator of the electrostatic motor according to the seventh embodiment of FIG. 20. [Figure 22] 21 is a cross-sectional view for assisting in the description of the configuration of the stator of the electrostatic motor according to the seventh embodiment of FIG. 20. FIG. [Figure 23] FIG. 21 is a perspective view for assisting in the description of the configuration of the rotor of the electrostatic motor according to the seventh embodiment of FIG. 20. [Figure 24]FIG. 13 is a perspective view showing the overall configuration of an electrostatic motor according to an eighth embodiment of the present disclosure, and is a perspective view for assisting in the description of the positional relationship between a plurality of stator electrodes and a plurality of rotor electrodes. [Figure 25] 25 is a perspective view showing one motor main body constituting the electrostatic motor according to the eighth embodiment of FIG. 24. FIG. [Figure 26] 25 is a perspective view showing a stator body that constitutes a part of the motor body in the eighth embodiment of FIG. 24. FIG. [Figure 27] 25 is a perspective view showing a rotor body that constitutes the motor body in the eighth embodiment of FIG. 24. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts are denoted by the same reference numerals in the drawings to simplify the description.

[0012] (First embodiment) Next, a first embodiment of an electrostatic motor 1 according to the present disclosure will be described with reference to FIGS. 1, 2, and 3. FIG. 1 is a perspective view showing the overall configuration of the electrostatic motor 1 according to this embodiment. FIG. 2 is a cross-sectional view of the electrostatic motor 1 of FIG. 1 cut along an imaginary plane including the axis S. FIG. 3 is a top view of the electrostatic motor 1 of FIG. 1 as viewed from one side in the axial direction Sz. The axial direction Sz refers to the direction in which the axis S extends. The electrostatic motor 1 according to this embodiment is mounted on various types of mobile equipment, such as spacecraft, aircraft, and drones. The electrostatic motor 1 is configured to be operable, for example, by being placed in a vacuum container and exposed to a vacuum.

[0013] As shown in Figures 1, 2, and 3, the electrostatic motor 1 includes a stator 10 and a rotor 20. The stator 10 includes stator support portions 11 and 12 and stator pillar portions 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h. Hereinafter, the stator pillar portions 13a, 13b, 13c, 13d, 13e, 13f, 13g, and 13h will also be collectively referred to as stator pillar portions 13a to 13h. The stator support portion 11 is formed in an annular shape centered on the axis S. The stator support portion 11 is formed in a plate shape with the axial direction Sz as its thickness direction.

[0014] The stator support portion 12 is disposed on the other side of the stator support portion 11 in the axial direction Sz. The stator support portion 12 is formed in an annular shape centered on the axis S. The stator support portion 12 is formed in a plate shape with the axial direction Sz as its thickness direction. The stator pillar portions 13a to 13h are each formed in a rectangular pillar shape extending in the axial direction Sz. The stator pillar portions 13a to 13h are also arranged at equal intervals in the circumferential direction centered on the axis S. The stator pillar portions 13a to 13h are each disposed between the stator support portions 11 and 12. One end of each of the stator pillar portions 13a to 13h in the axial direction Sz is connected to the stator support portion 11. The other end of each of the stator pillar portions 13a to 13h in the axial direction Sz is connected to the stator support portion 12.

[0015] As shown in FIG. 2, stator electrodes 50a, 51a, 52a, and 53a are connected to the stator column 13a. The stator electrodes 50a, 51a, 52a, and 53a are each formed to protrude radially inward from the stator column 13a about the axis S. The stator electrodes 50a, 51a, 52a, and 53a are arranged at intervals in the axial direction Sz. The stator electrode 50a is disposed on one side of the stator electrode 51a in the axial direction Sz. The stator electrode 51a is disposed on one side of the stator electrode 52a in the axial direction Sz. The stator electrode 52a is disposed on one side of the stator electrode 53a in the axial direction Sz. Hereinafter, the stator electrodes 50a, 51a, 52a, and 53a will be collectively referred to as a set of stator electrodes 50a to 53a.

[0016] Stator electrodes 50b, 51b, 52b, and 53b are connected to the stator column 13b. The stator electrodes 50b, 51b, 52b, and 53b are each formed to protrude radially inward from the stator column 13b about the axis S. Furthermore, the stator electrodes 50b, 51b, 52b, and 53b are arranged at intervals in the axial direction Sz. The stator electrode 50b is disposed on one side of the stator electrode 51b in the axial direction Sz. The stator electrode 51b is disposed on one side of the stator electrode 52b in the axial direction Sz. The stator electrode 52b is disposed on one side of the stator electrode 53b in the axial direction Sz. Hereinafter, the stator electrodes 50b, 51b, 52b, and 53b will be collectively referred to as a set of stator electrodes 50b to 53b.

[0017] Stator electrodes 50c, 51c, 52c, and 53c are connected to the stator column 13c. The stator electrodes 50c, 51c, 52c, and 53c are each formed to protrude radially inward from the stator column 13c about the axis S. Furthermore, the stator electrodes 50c, 51c, 52c, and 53c are arranged at intervals in the axial direction Sz. The stator electrode 50c is disposed on one side of the stator electrode 51c in the axial direction Sz. The stator electrode 51c is disposed on one side of the stator electrode 52c in the axial direction Sz. The stator electrode 52c is disposed on one side of the stator electrode 53c in the axial direction Sz. Hereinafter, the stator electrodes 50c, 51c, 52c, and 53c are collectively referred to as a set of stator electrodes 50c to 53c.

[0018] Stator electrodes 50d, 51d, 52d, and 53d are connected to the stator pole portion 13d. The stator electrodes 50d, 51d, 52d, and 53d are each formed to protrude radially inward from the stator pole portion 13d about the axis S. Furthermore, the stator electrodes 50d, 51d, 52d, and 53d are arranged at intervals in the axial direction Sz. The stator electrode 50d is disposed on one side of the stator electrode 51d in the axial direction Sz. The stator electrode 51d is disposed on one side of the stator electrode 52d in the axial direction Sz. The stator electrode 52d is disposed on one side of the stator electrode 53d in the axial direction Sz. Hereinafter, the stator electrodes 50d, 51d, 52d, and 53d are collectively referred to as a set of stator electrodes 50d to 53d.

[0019] Stator electrodes 50e, 51e, 52e, and 53e are connected to the stator column portion 13e. The stator electrodes 50e, 51e, 52e, and 53e are each formed to protrude radially inward from the stator column portion 13e about the axis S. Furthermore, the stator electrodes 50e, 51e, 52e, and 53e are arranged at intervals in the axial direction Sz. The stator electrode 50e is disposed on one side of the stator electrode 51e in the axial direction Sz. The stator electrode 51e is disposed on one side of the stator electrode 52e in the axial direction Sz. The stator electrode 52e is disposed on one side of the stator electrode 53e in the axial direction Sz. Hereinafter, the stator electrodes 50e, 51e, 52e, and 53e will be collectively referred to as a set of stator electrodes 50e to 53e.

[0020] Stator electrodes 50f, 51f, 52f, and 53f are connected to the stator pole portion 13f. The stator electrodes 50f, 51f, 52f, and 53f are each formed to protrude radially inward from the stator pole portion 13f about the axis S. Furthermore, the stator electrodes 50f, 51f, 52f, and 53f are arranged at intervals in the axial direction Sz. The stator electrode 50f is disposed on one side of the stator electrode 51f in the axial direction Sz. The stator electrode 51f is disposed on one side of the stator electrode 52f in the axial direction Sz. The stator electrode 52f is disposed on one side of the stator electrode 53f in the axial direction Sz. Hereinafter, the stator electrodes 50f, 51f, 52f, and 53f will be collectively referred to as a set of stator electrodes 50f to 53f.

[0021] Stator electrodes 50g, 51g, 52g, and 53g are connected to the stator pole portion 13g. The stator electrodes 50g, 51g, 52g, and 53g are each formed to protrude radially inward from the stator pole portion 13g about the axis S. Furthermore, the stator electrodes 50g, 51g, 52g, and 53g are arranged at intervals in the axial direction Sz. The stator electrode 50g is disposed on one side of the stator electrode 51g in the axial direction Sz. The stator electrode 51g is disposed on one side of the stator electrode 52g in the axial direction Sz. The stator electrode 52g is disposed on one side of the stator electrode 53g in the axial direction Sz. Hereinafter, the stator electrodes 50g, 51g, 52g, and 53g are collectively referred to as a set of stator electrodes 50g to 53g.

[0022] Stator electrodes 50h, 51h, 52h, and 53h are connected to the stator pole portion 13h. The stator electrodes 50h, 51h, 52h, and 53h are each formed to protrude radially inward from the stator pole portion 13h about the axis S. Furthermore, the stator electrodes 50h, 51h, 52h, and 53h are arranged at intervals in the axial direction Sz. The stator electrode 50h is disposed on one side of the stator electrode 51h in the axial direction Sz. The stator electrode 51h is disposed on one side of the stator electrode 52h in the axial direction Sz. The stator electrode 52h is disposed on one side of the stator electrode 53h in the axial direction Sz. Hereinafter, the stator electrodes 50h, 51h, 52h, and 53h are collectively referred to as a set of stator electrodes 50h to 53h.

[0023] In the stator 10 of the present embodiment configured as described above, the stator electrodes 50a, 50b, 50c, 50d, 50e, 50f, 50g, and 50h in FIG. 3 are arranged at equal intervals in the circumferential direction around the axis S. Similarly, the stator electrodes 51a, 51b, 51c, 51d, 51e, 51f, 51g, and 51h are arranged at equal intervals in the circumferential direction around the axis S. The stator electrodes 52a, 52b, 52c, 52d, 52e, 52f, 52g, and 52h are arranged at equal intervals in the circumferential direction around the axis S.

[0024] Stator electrodes 53a, 53b, 53c, 53d, 53e, 53f, 53g, and 53h are arranged at equal intervals in the circumferential direction around axis S. In addition, stator 10 of this embodiment forms an integrated component. That is, stator support portions 11 and 12, stator column portions 13a to 13h, and stator electrodes 50a to 53a, 50b to 53b, 50c to 53c, 50d to 53d, 50e to 53e, 50f to 53f, 50g to 53g, and 50h to 53h form an integrated component.

[0025] As shown in FIG. 2, the stator 10 is composed of a base material 10a and a plating layer 10b. The base material 10a is made of a resin material (e.g., ABS resin) with high mechanical strength. The base material of this embodiment is formed using a 3D printer or by injection molding. The plating layer 10b is formed as a thin film along the entire surface of the base material 10a. The plating layer 10b is made of a conductive metal material such as nickel or chromium. Nickel and chromium are materials with high spatial dielectric strength. The plating layer 10b is formed by plating the base material 10a.

[0026] As shown in FIGS. 1, 2, and 3, the rotor 20 includes rotor support portions 21 and 22, rotor pole portions 23a, 23b, 23c, 23d, 23e, 23f, 23g, and 23h, and a rotating shaft 24. Hereinafter, the rotor pole portions 23a, 23b, 23c, 23d, 23e, 23f, 23g, and 23h are collectively referred to as rotor pole portions 23a to 23h. The rotor support portions 21 and 22 are each formed in a disk shape with the axial direction Sz as its thickness direction and the axis S as its center. The rotor support portion 21 is disposed radially inward relative to the stator support portion 11, with the axis S as its center. The rotor support portion 22 is disposed radially inward relative to the stator support portion 12, with the axis S as its center. The rotor support portion 22 is disposed on the other side of the rotor support portion 21 in the axial direction Sz.

[0027] The rotor pillar portions 23a to 23h are arranged between the rotor support portions 21, 22. The rotor pillar portions 23a to 23h are each formed in a rectangular column shape extending in the axial direction Sz. The rotor pillar portions 23a to 23h are each arranged at equal intervals in the circumferential direction centered on the axis S. One end of each of the rotor pillar portions 23a to 23h in the axial direction Sz is connected to the rotor support portion 21. The other end of each of the rotor pillar portions 23a to 23h in the axial direction Sz is connected to the rotor support portion 22.

[0028] The rotating shaft 24 is formed in a cylindrical shape centered on the axis S. The rotating shaft 24 is formed to extend in the axial direction Sz. One side of the rotating shaft 24 in the axial direction Sz is connected to the rotor support portion 21. One end of the rotating shaft 24 in the axial direction Sz is formed to protrude from the rotor support portion 21 to one side in the axial direction Sz. The other side of the rotating shaft 24 in the axial direction Sz is connected to the rotor support portion 22. The other end of the rotating shaft 24 in the axial direction Sz is formed to protrude from the rotor support portion 22 to the other side in the axial direction Sz.

[0029] As shown in FIG. 2, rotor electrodes 60a, 61a, and 62a are connected to the rotor post portion 23a. The rotor electrodes 60a, 61a, and 62a are each formed to protrude radially outward from the rotor post portion 23a about the axis S. The rotor electrodes 60a, 61a, and 62a are arranged at intervals in the axial direction Sz. The rotor electrode 60a is disposed on one side of the rotor electrode 61a in the axial direction Sz. The rotor electrode 61a is disposed on one side of the rotor electrode 62a in the axial direction Sz. Hereinafter, the rotor electrodes 60a, 61a, and 62a will be collectively referred to as a set of rotor electrodes 60a to 62a.

[0030] Rotor electrodes 60b, 61b, and 62b are connected to the rotor base portion 23b. The rotor electrodes 60b, 61b, and 62b are each formed to protrude radially outward from the rotor base portion 23b about the axis S. The rotor electrodes 60b, 61b, and 62b are arranged at intervals in the axial direction Sz. The rotor electrode 60b is disposed on one side of the rotor electrode 61b in the axial direction Sz. The rotor electrode 61b is disposed on one side of the rotor electrode 62b in the axial direction Sz. Hereinafter, the rotor electrodes 60b, 61b, and 62b will be collectively referred to as a set of rotor electrodes 60b to 62b.

[0031] Rotor electrodes 60c, 61c, and 62c are connected to the rotor post portion 23c. The rotor electrodes 60c, 61c, and 62c are each formed to protrude radially outward from the rotor post portion 23c about the axis S. The rotor electrodes 60c, 61c, and 62c are arranged at intervals in the axial direction Sz. The rotor electrode 60c is disposed on one side of the rotor electrode 61c in the axial direction Sz. The rotor electrode 61c is disposed on one side of the rotor electrode 62c in the axial direction Sz. Hereinafter, the rotor electrodes 60c, 61c, and 62c will be collectively referred to as a set of rotor electrodes 60c to 62c.

[0032] Rotor electrodes 60d, 61d, and 62d are connected to the rotor base portion 23d. The rotor electrodes 60d, 61d, and 62d are each formed to protrude radially outward from the rotor base portion 23d about the axis S. The rotor electrodes 60d, 61d, and 62d are arranged at intervals in the axial direction Sz. The rotor electrode 60d is disposed on one side of the rotor electrode 61d in the axial direction Sz. The rotor electrode 61d is disposed on one side of the rotor electrode 62d in the axial direction Sz. Hereinafter, the rotor electrodes 60d, 61d, and 62d will be collectively referred to as a set of rotor electrodes 60d to 62d.

[0033] Rotor electrodes 60e, 61e, and 62e are connected to the rotor base portion 23e. The rotor electrodes 60e, 61e, and 62e are each formed to protrude radially outward from the rotor base portion 23e about the axis S. The rotor electrodes 60e, 61e, and 62e are arranged at intervals in the axial direction Sz. The rotor electrode 60e is disposed on one side of the rotor electrode 61e in the axial direction Sz. The rotor electrode 61e is disposed on one side of the rotor electrode 62e in the axial direction Sz. Hereinafter, the rotor electrodes 60e, 61e, and 62e will be collectively referred to as a set of rotor electrodes 60e to 62e.

[0034] Rotor electrodes 60f, 61f, and 62f are connected to the rotor base portion 23f. The rotor electrodes 60f, 61f, and 62f are each formed to protrude radially outward from the rotor base portion 23f about the axis S. The rotor electrodes 60f, 61f, and 62f are arranged at intervals in the axial direction Sz. The rotor electrode 60f is disposed on one side of the rotor electrode 61e in the axial direction Sz. The rotor electrode 61f is disposed on one side of the rotor electrode 62e in the axial direction Sz. Hereinafter, the rotor electrodes 60f, 61f, and 62f will be collectively referred to as a set of rotor electrodes 60f to 62f.

[0035] Rotor electrodes 60g, 61g, and 62g are connected to the rotor base portion 23g. The rotor electrodes 60g, 61g, and 62g are each formed to protrude radially outward from the rotor base portion 23g about the axis S. The rotor electrodes 60g, 61g, and 62g are arranged at intervals in the axial direction Sz. The rotor electrode 60g is disposed on one side of the rotor electrode 61g in the axial direction Sz. The rotor electrode 61g is disposed on one side of the rotor electrode 62g in the axial direction Sz. Hereinafter, the rotor electrodes 60g, 61g, and 62g will be collectively referred to as a set of rotor electrodes 60g to 62g.

[0036] Rotor electrodes 60h, 61h, and 62h are connected to the rotor base portion 23h. The rotor electrodes 60h, 61h, and 62h are each formed to protrude radially outward from the rotor base portion 23h about the axis S. The rotor electrodes 60h, 61h, and 62h are arranged at intervals in the axial direction Sz. The rotor electrode 60h is disposed on one side of the rotor electrode 61h in the axial direction Sz. The rotor electrode 61h is disposed on one side of the rotor electrode 62h in the axial direction Sz. Hereinafter, the rotor electrodes 60h, 61h, and 62h will be collectively referred to as a set of rotor electrodes 60h to 62h.

[0037] In the rotor 20 configured as above, a group of rotor electrodes 60a, 60b, 60c, 60d, 60e, 60f, 60g, and 60h shown in Fig. 3 are arranged at equal intervals in the circumferential direction around the axis S. Similarly, a group of rotor electrodes 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h are arranged at equal intervals in the circumferential direction around the axis S. A group of rotor electrodes 62a, 62b, 62c, 62d, 62e, 62f, 62g, and 62h are each arranged at equal intervals in the circumferential direction around the axis S.

[0038] In this embodiment, stator electrodes 50a, 50b, 50c, 50d, 50e, 50f, 50g, and 50h are collectively referred to as a group of stator electrodes 50a-50h. Stator electrodes 51a, 51b, 51c, 51d, 51e, 51f, 51g, and 51h are collectively referred to as a group of stator electrodes 51a-51h. Stator electrodes 52a, 52b, 52c, 52d, 52e, 52f, 52g, and 52h are collectively referred to as a group of stator electrodes 52a-52h. Stator electrodes 53a, 53b, 53c, 53d, 53e, 53f, 53g, and 53h are collectively referred to as a group of stator electrodes 53a-53h.

[0039] Furthermore, rotor electrodes 60a, 60b, 60c, 60d, 60e, 60f, 60g, and 60h are collectively referred to as a group of rotor electrodes 60a to 60h. Rotor electrodes 61a, 61b, 61c, 61d, 61e, 61f, 61g, and 61h are collectively referred to as a group of rotor electrodes 61a to 61h. Rotor electrodes 62a, 62b, 62c, 62d, 62e, 62f, 62g, and 62h are collectively referred to as a group of rotor electrodes 62a to 62h.

[0040] In this embodiment, the group of rotor electrodes 60a-60h is arranged between the group of stator electrodes 50a-50h and the group of stator electrodes 51a-51h. The group of rotor electrodes 61a-61h is arranged between the group of stator electrodes 51a-51h and the group of stator electrodes 52a-52h. The group of rotor electrodes 62a-62h is arranged between the group of stator electrodes 52a-52h and the group of stator electrodes 53a-53h.

[0041] A gap is formed between the group of rotor electrodes 60a-60h and the group of stator electrodes 50a-50h. A gap is formed between the group of rotor electrodes 60a-60h and the group of stator electrodes 51a-51h. A gap is formed between the group of rotor electrodes 61a-61h and the group of stator electrodes 51a-51h. A gap is formed between the group of rotor electrodes 61a-61h and the group of stator electrodes 52a-52h.

[0042] A gap is formed between the group of rotor electrodes 62a-62h and the group of stator electrodes 52a-52h. A gap is formed between the group of rotor electrodes 62a-62h and the group of stator electrodes 53a-53h. In this embodiment, the stator electrodes 50a-50h, 51a-51h, 52a-52h, 53a-53h and the rotor electrodes 60a-60h, 61a-61h, 62a-62h are aligned in the circumferential direction at equal intervals. The stator electrodes 50a-50h, 51a-51h, 52a-52h, 53a-53h and the rotor electrodes 60a-60h, 61a-61h, 62a-62h are aligned with a shift in the axial direction Sz.

[0043] The rotor 20 of this embodiment, configured as described above, is an integrated component. That is, the rotor support portions 21 and 22, the rotor column portions 23a-23h, and the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h form an integrated component. Specifically, the rotor 20 is composed of a base material 20a and a plating layer 20b. The base material 20a is formed from a resin material (e.g., ABS resin) with high mechanical strength.

[0044] In this embodiment, the base material 20a is formed by, for example, a 3D printer or injection molding. The plating layer 20b is formed as a thin film along the surface of the base material. The plating layer 20b is made of a conductive metal material such as nickel or chromium. The plating layer 20b is formed by plating the base material 20a. In the electrostatic motor 1 configured in this manner, the rotor 20 is configured to be rotatable in a rotation direction Ka around the axis S relative to the stator 10. Note that in FIGS. 1, 2, and 3, stator electrodes 51a, 52a, 53a, 52b, 53b, 51e, 52e, 53e, 51f, 52f, and 53f are not shown. Rotor electrodes 61a, 62a, 61d, 62d, 61f, and 62f are not shown.

[0045] Next, the electrical configuration of the electrostatic motor 1 of this embodiment will be described with reference to FIG. 4. FIG. 4 is a circuit diagram showing the configuration of an inverter circuit 2 for driving the rotor 20 of the electrostatic motor 1 of FIG. 1. As shown in FIG. 4, the inverter circuit 2 is a control unit including transistors 30 and 31, a capacitor 32, a drive circuit 33, and a rotation angle sensor 34. The transistors 30 and 31 are connected in series between the positive electrode and the negative electrode of a DC power supply 40. The drain terminal of the transistor 30 is connected to the positive electrode of the DC power supply 40. The source terminal of the transistor 30 is connected to the drain terminal of the transistor 30. The source terminal of the transistor 30 is connected to the negative electrode of the DC power supply 40.

[0046] The transistors 30 and 31 may be, for example, n-channel MOSFETs, i.e., metal-oxide-semiconductor field-effect transistors. The common connection terminal 41 is a terminal where the source terminal of the transistor 30 and the drain terminal of the transistor 31 are commonly connected. The common connection terminal 41 is electrically connected to the plating layer 20b of the rotor 20 of the electrostatic motor 1 using a brush or the like that slides on the plating layer 20b of the rotor 20. The negative electrode of the DC power supply 40 is electrically connected to the plating layer 10b of the stator 10. The capacitor 32 stabilizes the voltage between the positive and negative electrodes of the DC power supply 40. The drive circuit 33 is composed of a microcomputer, memory, etc. The drive circuit 33 executes control processing to control the rotor 20 via the transistors 30 and 31 based on the angle detected by the rotation angle sensor 34. The rotation angle sensor 34 detects the rotation angle of the rotor 20. The rotation angle sensor 34 may be an optical rotation angle sensor, a magnetic rotation angle sensor, or the like.

[0047] Next, the control process of the rotor 20 by the drive circuit 33 of this embodiment will be described with reference to Figure 4 and Figures 5(a), 5(b), 5(c), and 5(d). Figure 5(a) shows a state in which the inner peripheral portion 11b of the stator support portion 11 extends linearly in the horizontal direction in the figure, and a state in which the inner peripheral portion 21a of the rotor support portion 21 extends linearly in the horizontal direction in the figure, when the rotation direction Ka is the horizontal direction in the figure. In Figure 5(a), the rotor electrodes 60a, 60b are arranged horizontally, and the stator electrodes 50a, 50b, 50a are also arranged horizontally.

[0048] FIG. 5(b) shows the positional relationship between stator electrodes 50a, 50b, 51a, and 51b and rotor electrode 60a, and their respective polarities. FIG. 5(c) shows the relationship between the voltage applied between stator electrodes 50a, 50b, 51a, and 51b and rotor electrode 60a and the electrical angle. FIG. 6(a) is a timing chart showing the relationship between the electrical angle and time. FIG. 6(b) is a timing chart of the voltage applied to rotor electrode 60a. FIG. 5(d) shows the relationship between the rotational torque generated in rotor electrode 60a and the electrical angle. FIG. 6(c) is a timing chart of the rotational torque generated in rotor electrode 60a.

[0049] Hereinafter, the middle position between two pairs of adjacent stator electrodes in the rotation direction Ka among stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h will be referred to as the rotational middle position Zx. Figure 5(b) shows the rotational middle position Zx between stator electrodes 50a, 51a and stator electrodes 50b, 51b. Of the two pairs of adjacent stator electrodes, one pair of stator electrodes located on one side in the rotation direction Ka will be referred to as one pair of one-side stator electrodes.

[0050] Of the two adjacent stator electrodes, a set of stator electrodes located on the other side in the rotational direction Ka is referred to as a set of other-side stator electrodes. Stator electrodes 50a and 51a in FIG. 5(b) correspond to the set of other-side stator electrodes, and stator electrodes 50b and 51b correspond to the set of one-side stator electrodes. Here, the angular range centered on the axis S between the set of other-side stator electrodes and the rotational intermediate position Zx is referred to as an angular range (i.e., a second angular range) fa. The angular range centered on the axis S between the rotational intermediate position Zx and the set of one-side stator electrodes is referred to as an angular range (i.e., a first angular range) fb.

[0051] First, the inverter circuit 2 connects the plating layer 10b of the stator 10 to the negative electrode of the DC power supply 40. Therefore, eight pairs of stator electrodes 50a to 53a, 50b to 53b, 50c to 53c, 50d to 53d, 50e to 53e, 50f to 53f, 50g to 53g, and 50h to 53h are each one-side electrodes with negative polarity.

[0052] Based on the angle detected by the rotation angle sensor 34, the drive circuit 33 determines that the set of rotor electrodes 60a-62a is located between the rotational intermediate position Zx and the set of stator electrodes 50b-53b, as shown in FIGS. 5(a) and 5(b). This rotational intermediate position Zx is the intermediate position in the rotational direction Ka between the set of stator electrodes 50a-53a and the set of stator electrodes 50b-53b. The drive circuit 33 then turns on the transistor 30 and turns off the transistor 31. As a result, a positive voltage is applied from the DC power supply 40 to the plating layer 20b of the rotor 20 via the transistor 30.

[0053] As a result, current flows from the positive electrode of the DC power supply 40 through the transistor 30 to the plating layer 20b of the rotor 20. As a result, the polarity of the set of rotor electrodes 60a-62a (i.e., the electrodes on the other side) becomes positive. At this time, an attractive force due to electrostatic force is generated between the set of rotor electrodes 60a-62a and the set of stator electrodes 50b-53b. As a result, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the set of rotor electrodes 60a-62a.

[0054] At this time, the set of rotor electrodes 60b-62b is located between the rotational intermediate position Zx and the set of stator electrodes 50c-53c. This rotational intermediate position Zx is the intermediate position in the rotational direction Ka between the set of stator electrodes 50b-53b and the set of stator electrodes 50c-53c. The polarity of the set of rotor electrodes 60b-62b becomes positive. At this time, an attractive force due to electrostatic force is generated between the rotor electrodes 60b-62b and the set of stator electrodes 50c-53c. As a result, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the set of rotor electrodes 60b-62b.

[0055] At this time, the set of rotor electrodes 60c-62c is located between the rotational intermediate position Zx and the set of stator electrodes 50d-53d. This rotational intermediate position Zx is the intermediate position in the rotational direction Ka between the set of stator electrodes 50c-53c and the set of stator electrodes 50d-53d. The polarity of the set of rotor electrodes 60c-62c becomes positive. At this time, an attractive force due to electrostatic force is generated between the rotor electrodes 60c-62c and the set of stator electrodes 50d-53d. As a result, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the set of rotor electrodes 60c-62c.

[0056] Similarly, a rotational torque that rotates the rotor 20 toward one side of the rotation direction Ka is generated in the rotor electrodes 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. As a result, the rotor 20 rotates toward one side of the rotation direction Ka due to electrostatic attraction with respect to the stator 10. Thereafter, the drive circuit 33 determines, based on the angle detected by the rotation angle sensor 34, that the set of rotor electrodes 60a-62a has reached the same angle as the set of stator electrodes 50b-53b. The drive circuit 33 then turns off the transistor 30 and turns on the transistor 31. As a result, current flows from the plating layer 20b of the rotor 20 through the transistor 31 to the negative electrode of the DC power supply 40.

[0057] Therefore, the polarity of one set of rotor electrodes 60a-62a is negative. Similarly, the polarity of rotor electrodes 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h is negative. Therefore, no rotational torque due to electrostatic force is generated in rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. Therefore, rotor 20 rotates in one direction of rotation Ka due to inertia.

[0058] Next, based on the angle detected by the rotation angle sensor 34, the drive circuit 33 determines that the set of rotor electrodes 60a-62a has reached a rotational intermediate position Zx between the set of stator electrodes 50b-53b and the set of stator electrodes 50c-53c. The drive circuit 33 then turns on the transistor 30 and turns off the transistor 31. This causes a positive voltage to be applied from the DC power supply 40 through the transistor 30 to the plating layer 20b of the rotor 20. This causes a current to flow from the positive electrode of the DC power supply 40 through the transistor 30 to the plating layer 20b of the rotor 20. This causes the polarity of the set of rotor electrodes 60a-62a to become positive.

[0059] At this time, an attractive force due to electrostatic force is generated between one set of rotor electrodes 60a-62a and one set of stator electrodes 50c-53c. As a result, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in one set of rotor electrodes 60a-62a. Similarly, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in rotor electrodes 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. As a result, the rotor 20 rotates in one direction in the rotational direction Ka relative to the stator 10 due to the attractive force due to electrostatic force.

[0060] Thereafter, the drive circuit 33 determines that the set of rotor electrodes 60a-62a has reached the same angle as the set of stator electrodes 50c-53c, based on the angle detected by the rotation angle sensor 34. Then, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31. As a result, current flows from the plating layer 20b of the rotor 20 through the transistor 31 to the negative electrode of the DC power supply 40. As a result, the polarity of the set of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h becomes negative. Therefore, no rotational torque due to electrostatic force is generated in the rotor electrodes 60a to 62a, 60b to 62b, 60c to 62c, 60d to 62d, 60e to 62e, 60f to 62f, 60g to 62g, and 60h to 62h, and the rotor 20 rotates in one direction of rotation Ka due to inertia.

[0061] In this embodiment, which operates as described above, when the drive circuit 33 determines, based on the angle detected by the rotation angle sensor 34, that a set of rotor electrodes is located in the angle range fb, the drive circuit 33 turns on the transistor 30 and turns off the transistor 31. As a result, a current flows from the positive electrode of the DC power supply 40 through the transistor 30 to the plating layer 20b of the rotor 20. As a result, the polarities of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h become positive. At this time, a rotational torque that rotates the rotor 20 in one direction of the rotational direction Ka is generated in the rotor electrodes 60a to 62a, 60b to 62b, 60c to 62c, 60d to 62d, 60e to 62e, 60f to 62f, 60g to 62g, and 60h to 62h.

[0062] Next, when the drive circuit 33 determines, based on the angle detected by the rotation angle sensor 34, that one set of rotor electrodes is located within the angle range fa, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31. As a result, the plating layer 20b of the rotor 20 is connected to the negative electrode of the DC power supply 40 through the transistor 31. As a result, the polarity of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h becomes negative. As a result, no rotational torque due to electrostatic force is generated in the rotor 20, and the rotor 20 rotates in one direction of the rotation direction Ka due to inertia.

[0063] Next, the electrical angle used in the control process of the rotor 20 in this embodiment will be described with reference to Figures 5(c)(d) and 6(a), (b), and (c). The electrical angle in Figure 6(a) is expressed as an angle where one cycle of the control process of the rotor 20 is 360°. The electrical angle is a phase that represents the position in the rotational direction of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h.

[0064] The angular range centered on the axis S between one set of stator electrodes on one side and one set of stator electrodes on the other side corresponds to one cycle of the control process for the rotor 20. When one set of rotor electrodes among the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h is positioned at the same angle as one set of stator electrodes on the other side, the electrical angle is 0°. When one set of rotor electrodes among the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h is positioned at the same angle as one set of stator electrodes on one side, the electrical angle is 360°. Therefore, in this embodiment, an electrical angle of 360° corresponds to a mechanical angle of 45° about the axis S.

[0065] The drive circuit 33 turns on the transistor 30 and turns off the transistor 31 every time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°. Therefore, as shown in FIGS. 5(c) and 6(b), a positive voltage is applied between the stator 10 and the rotor 20 by the drive circuit 33. Therefore, as shown in FIGS. 5(d) and 6(c), a rotational torque is generated in the rotor 20 to rotate it in the rotation direction Ka every time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°.

[0066] Meanwhile, drive circuit 33 turns off transistor 30 and turns on transistor 31 to stop applying voltage between stator 10 and rotor 20 each time the electrical angle of rotor 20 reaches an angle range of 0° or more and less than 180°. As a result, the generation of rotational torque in rotor 20 stops each time the electrical angle of rotor 20 reaches an angle range of 180° or more and less than 360°. In this way, rotational torque is intermittently generated in rotor 20 each time the electrical angle of rotor 20 reaches an angle range of 180° or more and less than 360°.

[0067] Next, an electrostatic motor 1A, which is a comparative example of this embodiment, will be described with reference to Fig. 7 and Figs. 8(a), (b), (c), and (d). Fig. 7 is a perspective view showing the entire electrostatic motor 1A. Fig. 8(a) shows a state in which the inner peripheral portion 11b of the stator support portion 11 extends linearly in the horizontal direction in the figure, when the rotation direction Ka is the horizontal direction in the figure, and a state in which the inner peripheral portion 21a of the rotor support portion 21 extends linearly in the horizontal direction in the figure.

[0068] In Fig. 8(a), rotor electrodes 60a and 60b are arranged horizontally, and stator electrodes 50a, 50b, and 50a are arranged horizontally. Fig. 8(b) shows the positional relationship between stator electrodes 50a, 50b, 51a, and 51b and rotor electrode 60a. Fig. 8(c) shows the relationship between the voltage applied between stator electrodes 50a, 50b, 51a, and 51b and rotor electrode 60a and the electrical angle. Fig. 8(d) shows the relationship between the rotational torque generated in rotor electrode 60a and the electrical angle.

[0069] The polarities of the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h of the electrostatic motor 1A are different from those of the electrostatic motor 1. Specifically, the polarities of the stator electrodes 50a-53a, 50c-53c, 50e-53e, and 50g-53g of the electrostatic motor 1A are set to positive polarity. The polarities of the stator electrodes 50b-53b, 50d-53d, 50f-53f, and 50h-53h of the electrostatic motor 1A are set to negative polarity.

[0070] Furthermore, the polarities of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h differ between the electrostatic motor 1A and the electrostatic motor 1. As shown in FIGS. 8(a), 8(b), and 8(c), in the electrostatic motor 1A, when a set of rotor electrodes 60a-62a is positioned between the stator electrodes 50a-53a and the stator electrodes 50b-53b, the inverter circuit applies a positive voltage to the set of rotor electrodes 60a-62a. Therefore, the polarity of the set of rotor electrodes 60a-62a is set to positive. Therefore, a repulsive force due to electrostatic force is generated between the set of rotor electrodes 60a-62a and the set of stator electrodes 50a-53a. An attractive force due to electrostatic force is generated between one set of rotor electrodes 60a to 62a and one set of stator electrodes 50b to 53b.

[0071] At this time, the set of rotor electrodes 60b-62b is positioned between the set of stator electrodes 50b-53b and the set of stator electrodes 50c-53c. In this case, a negative voltage is applied to the set of rotor electrodes 60a-62a by the inverter circuit. As a result, the polarity of the set of rotor electrodes 60b-62b is set to negative. As a result, a repulsive force due to electrostatic force is generated between the set of rotor electrodes 60b-62b and the set of stator electrodes 50b-53b. An attractive force due to electrostatic force is generated between the set of rotor electrodes 60b-62b and the set of stator electrodes 50c-53c. As a result, as shown in FIG. 8(d), a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the rotor electrodes 60a-62a and 60b-62b, causing the rotor 20 to rotate in one direction in the rotational direction Ka.

[0072] When a set of rotor electrodes 60a-62a is positioned between a set of stator electrodes 50b-53b and a set of stator electrodes 50c-53c, a negative voltage is applied to the set of rotor electrodes 60a-62a by the inverter circuit. This sets the polarity of the set of rotor electrodes 60a-62a to negative. This generates a repulsive force due to electrostatic force between the set of rotor electrodes 60a-62a and the set of stator electrodes 50b-53b. This generates an attractive force due to electrostatic force between the set of rotor electrodes 60a-62a and the set of stator electrodes 50c-53c.

[0073] At this time, the set of rotor electrodes 60b-62b is positioned between the set of stator electrodes 50c-53c and the set of stator electrodes 50d-53d. In this case, a positive voltage is applied to the set of rotor electrodes 60b-62b by the inverter circuit. As a result, the polarity of the set of rotor electrodes 60b-62b is set to positive. Therefore, a repulsive force due to electrostatic force is generated between the set of rotor electrodes 60b-62b and the set of stator electrodes 50c-53c. An attractive force due to electrostatic force is generated between the set of rotor electrodes 60b-62b and the set of stator electrodes 50d-53d. As a result, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the rotor electrodes 60a-62a and 60b-62b, causing the rotor 20 to rotate in one direction in the rotational direction Ka.

[0074] Here, the polarity of each of the rotor electrodes 60c-62c, 60e-62e, and 60g-62g is set by an inverter circuit to be the same as the polarity of a set of rotor electrodes 60a-62a. The polarity of each of the rotor electrodes 60d-62d, 60f-62f, and 60h-62h is set by an inverter circuit to be the same as the polarity of a set of rotor electrodes 60b-62b. Therefore, the polarity of each of the rotor electrodes 60a-62a, 60c-62c, 60e-62e, and 60g-62g is switched by the inverter circuit depending on the rotational position of the rotor 20. The polarity of each of the rotor electrodes 60b-62b, 60d-62d, 60f-62f, and 60h-62h is switched by the inverter circuit depending on the rotational position of the rotor 20. As a result, a rotational torque is generated that rotates the rotor 20 in one direction of rotation Ka.

[0075] In this electrostatic motor 1A, the polarities of the stator electrodes 50a to 53a, 50c to 53c, 50e to 53e, and 50g to 53g are different from the polarities of the stator electrodes 50b to 53b, 50d to 53d, 50f to 53f, and 50h to 53h. Therefore, there is a risk of creeping discharge occurring between the stator electrodes 50a to 53a, 50c to 53c, 50e to 53e, and 50g to 53g and the stator electrodes 50b to 53b, 50d to 53d, 50f to 53f, and 50h to 53h. Therefore, electrical insulators 63a and 63b are provided between stator electrodes 50a to 53a, 50c to 53c, 50e to 53e, and 50g to 53g and stator electrodes 50b to 53b, 50d to 53d, 50f to 53f, and 50h to 53h.

[0076] Furthermore, the polarities of stator electrodes 50a to 53a, 50c to 53c, 50e to 53e, and 50g to 53g are different from the polarities of stator electrodes 50b to 53b, 50d to 53d, 50f to 53f, and 50h to 53h, respectively. Therefore, there is a risk of creeping discharge occurring between stator electrodes 50a to 53a, 50c to 53c, 50e to 53e, and 50g to 53g and stator electrodes 50b to 53b, 50d to 53d, 50f to 53f, and 50h to 53h.

[0077] Therefore, electrical insulators 64a and 64b are provided between stator electrodes 50a to 53a, 50c to 53c, 50e to 53e, and 50g to 53g and stator electrodes 50b to 53b, 50d to 53d, 50f to 53f, and 50h to 53h. In this way, in electrostatic motor 1A, electrical insulators 63a and 63b and electrical insulators 64a and 64b are provided, which leads to a complex structure and an increase in weight.

[0078] According to the present embodiment described above, the polarities of the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h are set to negative by the inverter circuit 2. When the drive circuit 33 determines that a set of rotor electrodes is located within the angle range fb based on the angle detected by the rotation angle sensor 34, it turns on the transistor 30 and turns off the transistor 31. Thus, a positive voltage is applied from the positive electrode of the DC power supply 40 to the plating layer 20b of the rotor 20 through the transistor 30. The one set of rotor electrodes is any one of the eight sets of rotor electrodes 60a to 62a, 60b to 62b, 60c to 62c, 60d to 62d, 60e to 62e, 60f to 62f, 60g to 62g, and 60h to 62h.

[0079] As a result, current flows from the positive electrode of the DC power supply 40 to the plating layer 20b of the rotor 20 through the transistor 30. As a result, the polarity of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h becomes positive. At this time, an attractive force due to electrostatic force is generated between one set of rotor electrodes and one set of stator electrodes. Therefore, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the one set of rotor electrodes.

[0080] Next, when the drive circuit 33 determines, based on the angle detected by the rotation angle sensor 34, that one set of rotor electrodes is located within the angle range fa, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31. This causes current to flow from the plating layer 20b of the rotor 20 through the transistor 31 to the negative electrode of the DC power supply 40. This causes the polarity of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h to become negative. This prevents the rotor 20 from generating rotational torque due to electrostatic force, and the rotor 20 rotates in one direction of the rotation direction Ka due to inertia.

[0081] On the other hand, in the electrostatic motor 1A in the comparative example, as described above, the electrical insulators 63a, 63b and the electrical insulators 64a, 64b are provided to suppress the occurrence of creeping discharge in the stator 10 and the rotor 20, resulting in a complex structure and increased weight. In contrast, in this embodiment, the polarities of all of the stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h are set to negative polarity. The polarities of all of the rotor electrodes 60a-60h, 61a-61h, and 62a-62h are set to positive polarity or negative polarity.

[0082] Therefore, creeping discharge does not occur on the stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h. Creeping discharge does not occur on the rotor electrodes 60a-60h, 61a-61h, and 62a-62h. Therefore, no electrical insulating material is provided on the stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h. No electrical insulating material is provided on the rotor electrodes 60a-60h, 61a-61h, and 62a-62h. In other words, electrical insulating material can be eliminated from the stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h and the rotor electrodes 60a-60h, 61a-61h, and 62a-62h. Therefore, it is possible to provide an electrostatic motor 1 that has a simple structure and is lightweight.

[0083] In this embodiment configured as above, the following operational effects (a) and (b) are obtained. (a) In this embodiment, the electrostatic motor generates rotational torque in the rotor 20 only when the electrical angle is equal to or greater than 180° and less than 360°. However, as described above, no creeping discharge occurs on the stator 10 or the rotor 20. Therefore, as shown by the dotted line in FIG. 5(c), the voltage applied from the drive circuit 33 to the rotor electrodes 60a-60h, 61a-61h, and 62a-62h can be increased. Therefore, as shown by the dotted line in FIG. 5(d), the rotational torque generated in the rotor 20 can be sufficiently increased.

[0084] (b) In the electrostatic motor of this embodiment, the stator 10 is disposed on the outer periphery of the electrostatic motor 1. Furthermore, the stator 10 is set to the same potential as the ground by the inverter circuit 2. This makes it possible to prevent problems such as electric leakage and electric shock caused by the stator 10. This improves the safety of the electrostatic motor 1.

[0085] Next, optimization of the electrode configuration of the electrostatic motor 1 of this embodiment will be described with reference to Figures 9(a) and 9(b). Figure 9(a) is a diagram showing the relative positions of the stator electrodes 50a, 50b, 51a, and 51b and the rotor electrodes 60a and 60b. Figure 9(b) is a diagram showing the relationship between the positions of the rotor electrodes 60a and 60b and the electrostatic force in the rotational direction Ka generated at the rotor electrodes 60a and 60b.

[0086] The distance Sz in the axial direction between the stator electrode and the rotor electrode is defined as distance d. If the electric charge generated on the rotor electrode is replaced by a single electric charge, the electrostatic force in the rotational direction Ka generated on the rotor electrode relative to the stator electrode is maximized when the distance in the rotational direction Ka between the stator electrode and the rotor electrode is distance d / √2. Therefore, in the electrostatic motor 1, the electrostatic force in the rotational direction Ka generated on the rotor 20 can be maximized by setting the number of poles such that the pitch P between the stator electrode and the rotor electrode satisfies the following formula 1.

[0087] P=d·4 / √2····Equation 1 However, in reality, the optimum value for the number of poles varies depending on the shape of the stator electrodes and rotor electrodes (for example, radial dimension, circumferential arrangement). For this reason, the optimum value for the number of poles can be calculated by an electric field analysis that takes into account the electric field and charge distribution due to the shape of the stator electrodes and rotor electrodes. Figure 10 shows the relationship between the rotational torque generated in the rotor 20, the number of poles, the electrode pitch, and the electrode diameter. As can be seen from Figure 10, there is an optimum value for the number of poles and the pitch P at which the rotational torque can be maximized.

[0088] The stator electrode pitch P is the distance in the rotation direction Ka between two adjacent stator electrodes among stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h. The rotor electrode pitch P is the distance in the rotation direction Ka between two adjacent rotor electrodes among rotor electrodes 60a-60h, 61a-61h, and 62a-62h.

[0089] In this embodiment, the number of stator electrode poles is the total number of stator electrodes in one group among four groups of stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h that are arranged in the circumferential direction centered on axis S. The number of rotor electrode poles is also the total number of rotor electrodes in one group among three groups of rotor electrodes 60a-60h, 61a-61h, and 62a-62h that are arranged in the circumferential direction centered on axis S.

[0090] (Second embodiment) In the first embodiment, an example was described in which the polarities of eight pairs of stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h were set to negative. Instead, in the second embodiment, the polarities of eight pairs of stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h are set to positive.

[0091] The electrostatic motor 1 of this embodiment differs from the electrostatic motor 1 of the first embodiment in the electrical circuit configuration of the inverter circuit 2. Therefore, the electrical circuit configuration of the inverter circuit 2 will be mainly described with reference to FIG. 11. FIG. 11 is a circuit diagram showing the overall electrical configuration of the inverter circuit 2 of this embodiment. In FIG. 11, the same reference numerals as in FIG. 4 indicate the same components, and their description will be omitted.

[0092] In the inverter circuit 2, the positive electrode of the DC power supply 40 is connected to the plating layer 10b of the stator 10. Therefore, the inverter circuit 2 sets the polarity of eight pairs of stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h (i.e., electrodes on one side) to positive polarity. Furthermore, a common connection terminal 41 between the transistors 30 and 31 is connected to the plating layer 20b of the rotor 20. Therefore, the polarity of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h (i.e., electrodes on the other side) changes depending on whether the transistors 30 and 31 are turned on or off.

[0093] Next, the operation of the inverter circuit 2 of this embodiment will be described with reference to Figures 12(a), 12(b), and 12(c). Figure 12(a) is a timing chart showing the relationship between electrical angle and time. Figure 12(b) is a timing chart showing voltages applied to eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. Figure 12(c) is a timing chart showing the rotational torque generated in the rotor 20. Any one pair of rotor electrodes among the eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h will be simply referred to as one pair of rotor electrodes.

[0094] First, when the drive circuit 33 determines that a set of rotor electrodes is located within the angle range fb based on the angle detected by the rotation angle sensor 34, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31. Therefore, the plating layer 20b of the rotor 20 is connected to the negative electrode of the DC power supply 40 through the transistor 31. Therefore, the polarity of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h becomes negative. At this time, an attractive force due to electrostatic force is generated between the set of rotor electrodes and one set of stator electrodes. Therefore, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the set of rotor electrodes.

[0095] Next, when drive circuit 33 determines, based on the angle detected by rotation angle sensor 34, that one set of rotor electrodes is located within angle range fa, drive circuit 33 turns on transistor 30 and turns off transistor 31. As a result, a positive voltage is applied from the positive electrode of DC power supply 40 to plating layer 20b of rotor 20 through transistor 30. As a result, current flows from the positive electrode of DC power supply 40 through transistor 31 to plating layer 20b of rotor 20. Therefore, the polarities of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h become positive.

[0096] At this time, a repulsive force due to electrostatic force is generated between one set of rotor electrodes and one set of stator electrodes on one side. This repulsive force is much smaller than the attractive force described above. Furthermore, a repulsive force due to electrostatic force is generated between one set of rotor electrodes and one set of stator electrodes on the other side. This repulsive force is much smaller than the attractive force described above. As a result, no rotational torque due to electrostatic force is generated in the rotor 20. Therefore, the rotor 20 rotates to one side in the rotation direction Ka due to inertia.

[0097] That is, in this embodiment, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31 each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°. Therefore, a positive voltage is applied between the stator 10 and the rotor 20 by the drive circuit 33, as shown in Figures 12(a) and 12(b). Therefore, each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°, a rotational torque is generated in the rotor 20, causing it to rotate in one direction of rotation Ka, as shown in Figure 12(c).

[0098] Meanwhile, the drive circuit 33 turns on the transistor 30 and turns off the transistor 31, stopping the application of voltage between the stator 10 and the rotor 20, each time the electrical angle of the rotor 20 reaches an angle range of 0° or more and less than 180°. As a result, no rotational torque for rotating the rotor 20 is generated. Therefore, each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°, the generation of rotational torque in the rotor 20 is stopped. In this way, rotational torque is intermittently generated in the rotor 20 each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°.

[0099] In the present embodiment described above, the polarities of all of the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h are set to positive polarity. The polarities of all of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h are set to positive polarity or negative polarity. Therefore, no creeping discharge occurs on the stator 10 or the rotor 20.

[0100] Therefore, no electrical insulating material is provided on the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h. No electrical insulating material is provided on the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. Therefore, an electrostatic motor 1 having a simple structure and reduced weight can be provided.

[0101] (Third embodiment) In the first embodiment, the polarity of eight pairs of stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h is set to negative. Instead, the polarity of eight pairs of stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h is switched. In the third embodiment, the polarity of eight pairs of stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h is switched.

[0102] The inverter circuit 2 of this embodiment differs from that of the first embodiment. Therefore, the inverter circuit 2 will be mainly described with reference to FIG. 13. FIG. 13 is a circuit diagram showing the overall configuration of the inverter circuit 2 of this embodiment. In FIG. 13, the same reference numerals as those in FIG. 4 indicate the same components, and their description will be omitted. In the inverter circuit 2, the negative electrode of the DC power supply 40 is connected to the plating layer 20b of the rotor 20. Therefore, the inverter circuit 2 sets the polarity of eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h to negative. A common connection terminal 41 between the transistors 30 and 31 is connected to the plating layer 10b of the stator 10.

[0103] Next, the operation of the inverter circuit 2 of this embodiment will be described with reference to Figures 14(a), (b), and (c). Figure 14(a) is a timing chart showing the relationship between electrical angle and time. Figure 14(b) is a timing chart of voltages applied to eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. Figure 14(c) is a timing chart of the rotational torque generated in the rotor 20.

[0104] First, when the drive circuit 33 determines, based on the angle detected by the rotation angle sensor 34, that a set of rotor electrodes is located within the angle range fb, the drive circuit 33 turns on the transistor 30 and turns off the transistor 31. This applies a positive voltage from the positive electrode of the DC power supply 40 to the plating layer 10b of the stator 10 through the transistor 30. Therefore, current flows from the positive electrode of the DC power supply 40 to the plating layer 10b of the stator 10 through the transistor 30. Therefore, the polarity of the eight sets of stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h becomes positive. At this time, an attractive force due to electrostatic force is generated between the set of rotor electrodes and one set of stator electrodes on one side. Therefore, a rotational torque that rotates the rotor 20 in one direction of the rotational direction Ka is generated in one pair of rotor electrodes.

[0105] Next, when the drive circuit 33 determines that the set of rotor electrodes is located within the angle range fa based on the angle detected by the rotation angle sensor 34, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31. Therefore, the plating layer 10b of the stator 10 is connected to the negative electrode of the DC power supply 40 through the transistor 31. Therefore, the polarity of the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h becomes negative. At this time, no electrostatic force is generated between the set of rotor electrodes and the set of stator electrodes on one side. Therefore, no rotational torque due to electrostatic force is generated in the rotor 20. As a result, the rotor 20 rotates to one side in the rotation direction Ka due to inertia.

[0106] 14(a) and 14(b), the drive circuit 33 turns on the transistor 30 and turns off the transistor 31 each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°. Therefore, a positive voltage is applied between the stator 10 and the rotor 20 by the drive circuit 33. Therefore, each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°, a rotational torque is generated due to the attractive force of the electrostatic force, which rotates the rotor 20 in one direction of the rotational direction Ka, as shown in FIG.

[0107] Meanwhile, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31 to stop applying voltage between the stator 10 and the rotor 20 each time the electrical angle of the rotor 20 reaches an angle range of 0° or more and less than 180°. As a result, no electrostatic force is generated to rotate the rotor 20. Therefore, the generation of rotational torque in the rotor 20 stops each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°. In this way, rotational torque is intermittently generated in the rotor 20 each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°.

[0108] In the present embodiment described above, the polarities of all of the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h are set to positive or negative polarities. The polarities of all of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h are set to positive polarities. Therefore, no creeping discharge occurs on the stator 10 or the rotor 20.

[0109] Therefore, no electrical insulating material is provided on the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h. No electrical insulating material is provided on the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. Therefore, an electrostatic motor 1 having a simple structure and reduced weight can be provided.

[0110] (Fourth embodiment) In the third embodiment, the polarities of the eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h are set to negative. In place of this, a fourth embodiment will be described in which the polarities of the eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h are set to positive.

[0111] The inverter circuit 2 is different between this embodiment and the third embodiment. Therefore, the inverter circuit 2 will be mainly described with reference to FIG. 15. FIG. 15 is a circuit diagram showing the overall configuration of the inverter circuit 2 of this embodiment. In FIG. 15, the same reference numerals as in FIG. 13 indicate the same components, and their description will be omitted. The inverter circuit 2 is different between this embodiment and the third embodiment. Therefore, the inverter circuit 2 will be mainly described with reference to FIG. 15.

[0112] In the inverter circuit 2, the positive electrode of the DC power supply 40 is connected to the plating layer 20b of the rotor 20. Therefore, the polarity of eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h is set to positive by the inverter circuit 2. A common connection terminal 41 between the transistors 30 and 31 is connected to the plating layer 10b of the stator 10.

[0113] Next, the operation of the inverter circuit 2 of this embodiment will be described with reference to Figures 15(a), (b), and (c). Figure 15(a) is a timing chart showing the relationship between electrical angle and time. Figure 15(b) is a timing chart of voltages applied to eight pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. Figure 15(c) is a timing chart of the rotational torque generated in the rotor 20.

[0114] First, when the drive circuit 33 determines that a set of rotor electrodes is located within the angle range fb based on the angle detected by the rotation angle sensor 34, the drive circuit 33 turns off the transistor 30 and turns on the transistor 31. Therefore, the plating layer 20b of the rotor 20 is connected to the negative electrode of the DC power supply 40 through the transistor 31. Therefore, the polarity of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h becomes negative. At this time, an attractive force due to electrostatic force is generated between the set of rotor electrodes and one set of stator electrodes. Therefore, a rotational torque that rotates the rotor 20 in one direction in the rotational direction Ka is generated in the set of rotor electrodes.

[0115] Next, when drive circuit 33 determines, based on the angle detected by rotation angle sensor 34, that one set of rotor electrodes is located within angle range fa, drive circuit 33 turns on transistor 30 and turns off transistor 31. As a result, a positive voltage is applied from the positive electrode of DC power supply 40 to plating layer 20b of rotor 20 through transistor 31. As a result, current flows from the positive electrode of DC power supply 40 to plating layer 20b of rotor 20 through transistor 31. Therefore, the polarities of eight sets of rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h become positive.

[0116] At this time, a repulsive force due to electrostatic force is generated between one set of rotor electrodes and one set of stator electrodes on one side. This repulsive force is much smaller than the attractive force described above. Furthermore, a repulsive force due to electrostatic force is generated between one set of rotor electrodes and one set of stator electrodes on the other side. This repulsive force is much smaller than the attractive force described above. As a result, no rotational torque due to electrostatic force is generated in the rotor 20. Therefore, the rotor 20 rotates to one side in the rotation direction Ka due to inertia.

[0117] 16(a) and 16(b), the drive circuit 33 turns off the transistor 30 and turns on the transistor 31 each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°. Therefore, a positive voltage is applied between the stator 10 and the rotor 20 by the drive circuit 33. Therefore, each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°, a rotational torque is generated in the rotor 20 to rotate it in one direction of rotation Ka, as shown in FIG.

[0118] Meanwhile, the drive circuit 33 turns on the transistor 30 and turns off the transistor 31, stopping the application of voltage between the stator 10 and the rotor 20, each time the electrical angle of the rotor 20 reaches an angle range of 0° or more and less than 180°. As a result, no electrostatic force is generated to rotate the rotor 20. Therefore, each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°, the generation of rotational torque in the rotor 20 stops. In this way, rotational torque is intermittently generated in the rotor 20 each time the electrical angle of the rotor 20 reaches an angle range of 180° or more and less than 360°.

[0119] In the present embodiment described above, the polarities of all of the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h are set to positive polarity. The polarities of all of the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h are set to positive polarity or negative polarity. Therefore, no creeping discharge occurs on the stator 10 or the rotor 20.

[0120] Therefore, no electrical insulating material is provided on the stator electrodes 50a-53a, 50b-53b, 50c-53c, 50d-53d, 50e-53e, 50f-53f, 50g-53g, and 50h-53h. No electrical insulating material is provided on the rotor electrodes 60a-62a, 60b-62b, 60c-62c, 60d-62d, 60e-62e, 60f-62f, 60g-62g, and 60h-62h. Therefore, an electrostatic motor 1 having a simple structure and reduced weight can be provided.

[0121] (Fifth embodiment) In the first embodiment described above, an example was described in which a set of stator electrodes 50a-53a were arranged in the axial direction Sz. However, instead of this, a fifth embodiment in which a set of stator electrodes 50a-53a are arranged in a radial direction centered on the axis S will be described with reference to FIG. 17. FIG. 17 is a cross-sectional view of the electrostatic motor 1 of this embodiment, cut along an imaginary plane including the axis S. As shown in FIGS. 17 and 18, the electrostatic motor 1 of this embodiment includes a stator 10, a rotor 20, a housing 70, and bearings 80a and 80b.

[0122] The stator 10 includes a stator support portion 11 and four sets of stator electrodes 50a-53a, 50b-53b, 50c-53c, and 50d-53d. The stator support portion 11 is formed in a disk shape with the axial direction Sz as its thickness direction and the axis S as its center. As shown in FIG. 17, the four sets of stator electrodes 50a-53a, 50b-53b, 50c-53c, and 50d-53d are arranged on one side of the axial direction Sz with respect to the stator support portion 11. FIG. 18 is a diagram showing the relative positions of the stator electrodes 50a-53a, 50b-53b, 50c-53c, and 50d-53d, the rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d, and the rotating shaft 24. 18 is a cross-sectional view of stator electrodes 50a to 53a, 50b to 53b, 50c to 53c, and 50d to 53d, rotor electrodes 60a to 62a, 60b to 62b, 60c to 62c, and 60d to 62d, and rotating shaft 24 in FIG. 17, cut by an imaginary plane perpendicular to the axis.

[0123] Each of the four sets of stator electrodes 50a-53a, 50b-53b, 50c-53c, and 50d-53d is formed to extend from the stator support portion 11 to one side in the axial direction Sz. Each of the four sets of stator electrodes 50a-53a, 50b-53b, 50c-53c, and 50d-53d has an end on the other side in the axial direction Sz connected to the stator support portion 11. Each of the sets of stator electrodes 50a-53a is arranged in the radial direction Cy about the axis S. Each of the sets of stator electrodes 50b-53b is arranged in the radial direction Cy about the axis S. Each of the sets of stator electrodes 50c-53c is arranged in the radial direction Cy about the axis S. Each set of stator electrodes 50d to 53d is arranged in a radial direction Cy about the axis S.

[0124] The group of stator electrodes 50a, 50b, 50c, and 50d are each arranged at equal intervals in the circumferential direction around the axis S. The group of stator electrodes 51a, 51b, 51c, and 51d are each arranged at equal intervals in the circumferential direction around the axis S. The group of stator electrodes 52a, 52b, 52c, and 52d are each arranged at equal intervals in the circumferential direction around the axis S. The group of stator electrodes 53a, 53b, 53c, and 53d are each arranged at equal intervals in the circumferential direction around the axis S.

[0125] The first group of stator electrodes 50a, 50b, 50c, and 50d are arranged radially inwardly of the first group of stator electrodes 51a, 51b, 51c, and 51d in the radial direction Cy about the axis S. The first group of stator electrodes 51a, 51b, 51c, and 51d are arranged radially inwardly of the first group of stator electrodes 52a, 52b, 52c, and 52d in the radial direction Cy about the axis S. The first group of stator electrodes 52a, 52b, 52c, and 52d are arranged radially inwardly of the first group of stator electrodes 53a, 53b, 53c, and 53d in the radial direction Cy about the axis S. Furthermore, the stator support 11 and the stator electrodes 50a to 53a, 50b to 53b, 50c to 53c, and 50d to 53d of this embodiment are made of a base material and a plating layer, similar to the first embodiment.

[0126] As shown in FIGS. 17 and 18, the rotor 20 includes a rotor support portion 21, four sets of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d, and a rotating shaft 24. The rotor support portion 21 is formed in a disk shape with the axial direction Sz as its thickness direction and its center on the axis S. The rotor support portion 21 is disposed on one side of the stator support portion 11 in the axial direction Sz. The four sets of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d are each formed to extend from the rotor support portion 21 to the other side in the axial direction Sz. One end of each of the four sets of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d in the axial direction Sz is connected to the rotor support portion 21.

[0127] Each set of rotor electrodes 60a-62a is arranged in the radial direction around the axis S. Each set of rotor electrodes 60b-62b is arranged in the radial direction Cy around the axis S. Each set of rotor electrodes 60c-62c is arranged in the radial direction Cy around the axis S. Each set of rotor electrodes 60d-62d is arranged in the radial direction Cy around the axis S. A group of rotor electrodes 60a, 60b, 60c, 60d are arranged at equal intervals in the circumferential direction around the axis S. A group of rotor electrodes 61a, 61b, 61c, 61d are arranged at equal intervals in the circumferential direction around the axis S. A group of rotor electrodes 62a, 62b, 62c, 62d are arranged at equal intervals in the circumferential direction around the axis S.

[0128] The first group of rotor electrodes 60a, 60b, 60c, and 60d is arranged between the first group of stator electrodes 50a, 50b, 50c, and 50d and the first group of stator electrodes 51a, 51b, 51c, and 51d. The first group of rotor electrodes 61a, 61b, 61c, and 61d is arranged between the first group of stator electrodes 51a, 51b, 51c, and 51d and the first group of stator electrodes 52a, 52b, 52c, and 52d. The first group of rotor electrodes 62a, 62b, 62c, and 62d is arranged between the first group of stator electrodes 52a, 52b, 52c, and 52d and the first group of stator electrodes 53a, 53b, 53c, and 53d. That is, the stator electrodes 50a to 50d, 51a to 51d, 52a to 52d, and 53a to 53d are arranged so as to be shifted (ie, offset) from the rotor electrodes 60a to 60d, 61a to 61d, and 62a to 62d in the radial direction Cy.

[0129] Hereinafter, one group of stator electrodes 50a, 50b, 50c, and 50d will be referred to as one group of stator electrodes 50a-50d. One group of stator electrodes 51a, 51b, 51c, and 51d will be referred to as one group of stator electrodes 51a-51d. One group of stator electrodes 52a, 52b, 52c, and 52d will be referred to as one group of stator electrodes 52a-52d. One group of stator electrodes 53a, 53b, 53c, and 53d will be referred to as one group of stator electrodes 53a-53d. One group of rotor electrodes 60a, 60b, 60c, and 60d will be referred to as one group of rotor electrodes 60a-60d. One group of rotor electrodes 61a, 61b, 61c, and 61d will be referred to as one group of rotor electrodes 61a-61d. A group of rotor electrodes 62a, 62b, 62c, and 62d is referred to as a group of rotor electrodes 62a to 62d.

[0130] In this embodiment, the stator electrodes 50a-50d, 51a-51d, 52a-52d, and 53a-53d and the rotor electrodes 60a-60d, 61a-61d, and 62a-62d are arranged at equal intervals in the circumferential direction about the axis S. The rotating shaft 24 is formed in a cylindrical shape that extends in the axial direction Sz about the axis S. The other side of the rotating shaft 24 in the axial direction Sz passes through the through-hole 11a of the stator support portion 11. One side of the rotating shaft 24 in the axial direction Sz is connected to the rotor support portion 21 while passing through the rotor support portion 21.

[0131] The housing 70 has a hollow portion 70a that houses the stator 10 and the rotor 20 and is formed in a cylindrical shape centered on the axis S. Specifically, the housing 70 includes an outer peripheral portion 71, a bottom portion 72, and a lid portion 73. The outer peripheral portion 71 is formed so as to cover the stator 10 and the rotor 20 from the radial outside about the axis S. The bottom portion 72 is formed in a disk shape centered on the axis S and with the axial direction Sz as its thickness direction. The bottom portion 72 is formed so as to cover the opening of the outer peripheral portion 71 on the other side in the axial direction Sz. An opening 72a that opens in the axial direction Sz is provided in a central portion of the bottom portion 72 centered on the axis S.

[0132] The lid portion 73 is formed in a disk shape centered on the axis S and with the axial direction Sz as its thickness direction. The lid portion 73 is formed to cover the opening of the outer circumferential portion 71 on the other side in the axial direction Sz. An opening 73a that opens in the axial direction Sz is provided in a central portion of the lid portion 73 that is centered on the axis S. The bearing 80a is disposed in the opening 72a of the bottom portion 72. The bearing 80a rotatably supports the rotating shaft 24 while being supported by the bottom portion 72. The bearing 80b is disposed in the opening 73a of the lid portion 73. The bearing 80b rotatably supports the rotating shaft 24 while being supported by the lid portion 73.

[0133] In this embodiment, the hollow portion 70a of the housing 70 is sealed in a vacuum state and maintained at a vacuum. Therefore, the stator 10 and the rotor 20 operate by being exposed to the vacuum within the hollow portion 70a of the housing 70. Similarly to the first embodiment, the rotor support portion 21, the four sets of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d, and the rotating shaft 24 are made of a base material and a plating layer.

[0134] In this embodiment, similarly to the first embodiment, the inverter circuit applies a positive voltage to the four pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d. The stator 10 and rotor 20 of this embodiment then operate in the same manner as the stator 10 and rotor 20 of the first embodiment. This causes intermittent rotational torque to be generated in the rotor 20 due to electrostatic attraction between the four pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d. This causes the rotor 20 to rotate toward one side of the rotational direction Ka.

[0135] According to the present embodiment described above, the polarities of all of the stator electrodes 50a-50d, 51a-51d, 52a-52d, and 53a-53d are set to negative polarity. Furthermore, the polarities of all of the rotor electrodes 60a-60d, 61a-61d, and 62a-62d are set to positive polarity or negative polarity. Therefore, creeping discharge does not occur on the stator 10 and the rotor 20. Therefore, no electrical insulating material is provided on the stator electrodes 50a-50d, 51a-51d, 52a-52d, and 53a-53d. No electrical insulating material is provided on the rotor electrodes 60a-60d, 61a-61d, and 62a-62d. Therefore, it is possible to provide an electrostatic motor 1 that has a simple structure and is lightweight.

[0136] (Sixth embodiment) In the fifth embodiment, an example was described in which a set of stator electrodes 50a-53a and a set of rotor electrodes 60a-62a are each formed to extend in the axial direction Sz. However, instead of this, a sixth embodiment will be described with reference to FIG. 19 in which a set of stator electrodes 50a-53a and a set of rotor electrodes 60a-62a are each formed to extend in a radial direction centered on the axis S. FIG. 19 is a cross-sectional view of the electrostatic motor 1 of this embodiment, taken along an imaginary plane including the axis S. In FIG. 19, the same reference numerals as in FIG. 17 are the same or substantially the same, and their description will be simplified.

[0137] In this embodiment, a set of stator electrodes 50b-53b and a set of rotor electrodes 60b-62b are each formed to extend in a radial direction centered on the axis S. A set of stator electrodes 50c-53c and a set of rotor electrodes 60c-62c are each formed to extend in a radial direction centered on the axis S. A set of stator electrodes 50d-53d and a set of rotor electrodes 60d-62d are each formed to extend in a radial direction centered on the axis S.

[0138] The set of stator electrodes 50a-53a are each arranged in the axial direction Sz. The set of stator electrodes 50b-53b are each arranged in the axial direction Sz. The set of stator electrodes 50c-53c are each arranged in the axial direction Sz. The set of stator electrodes 50d-53d are each arranged in the axial direction Sz. Furthermore, the group of stator electrodes 50a, 50b, 50c, and 50d are arranged at equal intervals in the circumferential direction around the axis S. The group of stator electrodes 51a, 51b, 51c, and 51d are arranged at equal intervals in the circumferential direction around the axis S. The group of stator electrodes 52a, 52b, 52c, and 52d are arranged at equal intervals in the circumferential direction around the axis S. The group of stator electrodes 53a, 53b, 53c, and 53d are arranged at equal intervals in the circumferential direction around the axis S.

[0139] The first group of stator electrodes 50a, 50b, 50c, and 50d are arranged on one side of the first group of stator electrodes 51a, 51b, 51c, and 51d in the axial direction Sz. The first group of stator electrodes 51a, 51b, 51c, and 51d are arranged on one side of the first group of stator electrodes 52a, 52b, 52c, and 52d in the axial direction Sz. The first group of stator electrodes 52a, 52b, 52c, and 52d are arranged on one side of the first group of stator electrodes 53a, 53b, 53c, and 53d in the axial direction Sz. The four sets of stator electrodes 50a to 53a, 50b to 53b, 50c to 53c, and 50d to 53d have their radially outer ends, centered on the axis S, connected to the stator support part 11. The stator support portion 11 is formed in a cylindrical shape centered on the axis S. The stator support portion 11 is connected to an outer periphery 71 of the housing .

[0140] Each set of rotor electrodes 60a-62a is aligned in the axial direction Sz. Each set of rotor electrodes 60b-62b is aligned in the axial direction Sz. Each set of rotor electrodes 60c-62c is aligned in the axial direction Sz. Each set of rotor electrodes 60d-62d is aligned in the axial direction Sz. In this embodiment, as in the sixth embodiment, the stator electrodes 50a-50d, 51a-51d, 52a-52d, and 53a-53d and the rotor electrodes 60a-60d, 61a-61d, and 62a-62d are aligned at equal intervals in the circumferential direction around the axis S.

[0141] A group of rotor electrodes 60a, 60b, 60c, and 60d is arranged between a group of stator electrodes 50a, 50b, 50c, and 50d and a group of stator electrodes 51a, 51b, 51c, and 51d. A group of rotor electrodes 61a, 61b, 61c, and 61d is arranged between a group of stator electrodes 51a, 51b, 51c, and 51d and a group of stator electrodes 52a, 52b, 52c, and 52d. A group of rotor electrodes 62a, 62b, 62c, and 62d is arranged between a group of stator electrodes 52a, 52b, 52c, and 52d and a group of stator electrodes 53a, 53b, 53c, and 53d. That is, the stator electrodes 50a-50d, 51a-51d, 52a-52d, and 53a-53d are arranged with a deviation (i.e., offset) in the axial direction Sz relative to the rotor electrodes 60a-60d, 61a-61d, and 62a-62d. The four sets of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d each have a radially inner end centered on the axis S connected to the rotor support portion 21. The rotor support portion 21 is formed in a cylindrical shape centered on the axis S. The rotating shaft 24 is connected to the rotor support portion 21 while passing through a hollow portion of the rotor support portion 21.

[0142] In this embodiment configured as described above, similar to the first embodiment, the inverter circuit intermittently applies a positive voltage to the four pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d. As a result, a rotational torque that rotates the rotor 20 is intermittently generated in the four pairs of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d due to an attractive force caused by electrostatic force. This causes the rotor 20 to rotate in one direction of rotation Ka.

[0143] According to the present embodiment described above, the polarities of all of the stator electrodes 50a-50d, 51a-51d, 52a-52d, and 53a-53d are set to negative polarity. The polarities of all of the rotor electrodes 60a-60d, 61a-61d, and 62a-62d are set to positive polarity or negative polarity. Therefore, creeping discharge does not occur on the stator 10 and the rotor 20. Therefore, no electrical insulating material is provided on the stator electrodes 50a-50d, 51a-51d, 52a-52d, and 53a-53d. No electrical insulating material is provided on the rotor electrodes 60a-60d, 61a-61d, and 62a-62d. Therefore, it is possible to provide an electrostatic motor 1 that has a simple structure and is lightweight.

[0144] Seventh embodiment In the sixth embodiment, an example was described in which the stator support portion 11 of the stator 10 is formed so as to be surrounded by the housing 70. However, a seventh embodiment in which the stator support portion 11 of the stator 10 is formed so as to be exposed to the outside will be described with reference to FIGS. 20, 21, 22, and 23. FIG. 20 is a perspective view showing the overall configuration of the electrostatic motor 1 of this embodiment. FIG. 21 is a perspective view showing the stator 10 of the electrostatic motor 1 of FIG. 20. FIG. 22 is a cross-sectional view showing the inside of the stator 10 of the electrostatic motor 1 of FIG. 20. FIG. 23 is a perspective view showing the rotor 20 of the electrostatic motor 1 of FIG. 20.

[0145] As shown in FIGS. 20, 21, and 22, the stator 10 includes a stator support portion 11 and a plurality of stator electrodes 50. The stator support portion 11 is formed in a cylindrical shape centered on the axis S. The plurality of stator electrodes 50 are provided in place of the four sets of stator electrodes 50a to 53a, 50b to 53b, 50c to 53c, and 50d to 53d in the sixth embodiment. The plurality of stator electrodes 50 are dispersedly disposed in the circumferential direction about the axis S and in the axial direction Sz. The plurality of stator electrodes 50 are arranged at equal intervals in the circumferential direction about the axis S. The radially outer ends of each of the plurality of stator electrodes 50, centered on the axis S, are connected to the inner circumferential surface of the stator support portion 11. As in the sixth embodiment, the stator 10 is composed of a base material and a plating layer.

[0146] As shown in FIGS. 20 and 23, the rotor 20 includes a rotor support portion 21 and a plurality of rotor electrodes 60. The rotor support portion 21 is formed in a cylindrical shape centered on the axis S. The rotor support portion 21 is arranged radially inward of the plurality of stator electrodes 50, centered on the axis S. The plurality of rotor electrodes 60 are provided in place of the four sets of rotor electrodes 60a-62a, 60b-62b, 60c-62c, and 60d-62d in the sixth embodiment. The plurality of rotor electrodes 60 are arranged dispersedly in the circumferential direction about the axis S and in the axial direction Sz. The plurality of rotor electrodes 60 are arranged at equal intervals in the circumferential direction about the axis S.

[0147] In this embodiment, the multiple stator electrodes 50 and the multiple rotor electrodes 60 are arranged at equal intervals in the circumferential direction centered on the axis S. The multiple rotor electrodes 60 are each arranged offset in the axial direction Sz relative to the multiple stator electrodes 50. Specifically, the multiple rotor electrodes 60 and the multiple stator electrodes 50 are arranged so that they are alternately arranged one by one in the axial direction Sz. Each of the multiple rotor electrodes 60 has its radially inner end centered on the axis S connected to the outer circumferential surface of the rotor support portion 21. As in the sixth embodiment, the rotor 20 is made of a base material and a plating layer.

[0148] In this embodiment configured as described above, similar to the first embodiment, the inverter circuit intermittently applies a positive voltage to the rotor 20. Therefore, the stator electrodes 50 operate similarly to the stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h of the first embodiment. The rotor electrodes 60 operate similarly to the rotor electrodes 60a-60h, 61a-61h, and 62a-62h of the first embodiment. The stator 10 and rotor 20 of this embodiment operate similarly to the stator 10 and rotor 20 of the first embodiment. Therefore, due to the electrostatic attraction between the stator electrodes 50 and the rotor electrodes 60, a rotational torque that rotates the rotor 20 is intermittently generated in the rotor electrodes. This causes the rotor 20 to rotate in one direction of the rotational direction Ka.

[0149] According to the present embodiment described above, the polarity of all of the stator electrodes 50 is set to negative. The polarity of all of the rotor electrodes 60 is set to positive or negative. Therefore, creeping discharge does not occur on the stator 10 and rotor 20. Therefore, the stator electrodes are not provided with electrical insulation. Therefore, the rotor electrodes 60 are not provided with electrical insulation. Therefore, it is possible to provide an electrostatic motor 1 that has a simple structure and is lightweight.

[0150] In this embodiment, the stator 10 is an integrated component that is molded, for example, by a 3D printer. This has the advantages of reducing the number of parts, eliminating the need for assembly in the manufacturing process, and making it easier to manage the gap between the stator electrodes. Similarly, the rotor 20 is an integrated component that is molded, for example, by a 3D printer. This has the advantages of reducing the number of parts, eliminating the need for assembly in the manufacturing process, and making it easier to manage the gap between the rotor electrodes.

[0151] (Eighth embodiment) In the first embodiment, the electrostatic motor 1 is described as having one stator support portion 11 and one rotor support portion 21. However, instead, in the eighth embodiment, an electrostatic motor 1 is described as having a plurality of stator support portions 11 and a plurality of rotor support portions 21 with reference to FIGS. 24, 25, 26, and 27. FIG. 24 is a perspective view showing the overall configuration of the electrostatic motor 1 of this embodiment. FIG. 25 is a perspective view showing a motor main body portion 1X that constitutes the electrostatic motor 1 of FIG. 24. FIG. 26 is a perspective view showing one stator support portion 11 that constitutes the motor main body portion 1X in FIG. 25. FIG. 27 is a perspective view showing one rotor support portion 21 that constitutes the motor main body portion 1X in FIG. 25.

[0152] As shown in FIG. 24, the electrostatic motor 1 includes a plurality of motor main bodies 1X. The plurality of motor main bodies 1X are aligned in the axial direction Sz. The plurality of motor main bodies 1X include a plurality of stator main bodies 10A and a plurality of rotor main bodies 20A. The plurality of stator main bodies 10A each include a stator support portion 11 and a plurality of stator electrodes 50. The stator support portion 11 is formed in a cylindrical shape centered on the axis S. As a result, the electrostatic motor 1 has a plurality of stator support portions 11 aligned in the axial direction Sz.

[0153] The multiple stator support portions 11 are connected to each other and integrated. The multiple stator electrodes 50 are arranged in a line in the circumferential direction centered on the axis S, as shown in FIG. 24 . The radially outer ends of the multiple stator electrodes 50, centered on the axis S, are connected to the inner peripheral surfaces of the stator support portions 11. As a result, the multiple stator electrodes 50 are distributed in the axial direction Sz and the circumferential direction centered on the axis S in the multiple motor main bodies 1X. The multiple stator electrodes 50 are arranged at equal intervals in the circumferential direction centered on the axis S. Therefore, the multiple stator electrodes 50 operate in the same manner as the stator electrodes 50a to 53a, 50b to 53b, 50c to 53c, 50d to 53d, 50e to 53e, 50f to 53f, 50g to 53g, and 50h to 53h of the first embodiment.

[0154] The multiple rotor main bodies 20A are aligned in the axial direction Sz. Each of the multiple rotor main bodies 20A includes a rotor support 21 and multiple rotor electrodes 60. The rotor support 21 is formed in a cylindrical shape centered on the axis S. As a result, the electrostatic motor 1 has multiple rotor support parts 21 aligned in the axial direction Sz. The multiple rotor support parts 21 are connected to each other and integrated. As shown in FIG. 25 , the multiple rotor electrodes 60 are aligned in a row in the circumferential direction centered on the axis S.

[0155] The rotor electrodes 60 each have a radially inner end portion centered on the axis S connected to the outer circumferential surface of the rotor support portion 21. As a result, the rotor electrodes 60 are arranged in the motor main bodies 1X in a dispersed manner in the axial direction Sz and the circumferential direction centered on the axis S. The rotor electrodes 60 are arranged at equal intervals in the circumferential direction centered on the axis S. In this embodiment, the stator electrodes 50 and the rotor electrodes 60 are arranged at equal intervals in the circumferential direction centered on the axis S. Specifically, the rotor electrodes 60 and the stator electrodes 50 are arranged so that they are alternately arranged one by one in the axial direction Sz. Therefore, the rotor electrodes 60 operate in the same manner as the rotor electrodes 60a to 62a, 60b to 62b, 60c to 62c, 60d to 62d, 60e to 62e, 60f to 62f, 60g to 62g, and 60h to 62h in the first embodiment.

[0156] In this embodiment configured as described above, similar to the first embodiment, the inverter circuit intermittently applies a positive voltage to the plurality of rotor electrodes 60. As a result, due to the electrostatic attraction between the plurality of stator electrodes 50 and the plurality of rotor electrodes 60, a rotational torque that rotates the rotor 20 is intermittently generated in the four sets of the plurality of rotor electrodes. As a result, the rotor 20 rotates to one side of the rotational direction Ka.

[0157] According to the present embodiment described above, the polarity of all of the stator electrodes 50 is set to negative. The polarity of all of the rotor electrodes 60 is set to positive or negative. Therefore, creeping discharge does not occur on the stator 10 and rotor 20. Therefore, electrical insulation material is not provided on the stator electrodes. No insulation material is provided on the rotor electrodes 60. Therefore, it is possible to provide an electrostatic motor 1 that has a simple structure and is lightweight. In addition, in this embodiment, the output of the electrostatic motor 1 can be adjusted by adjusting the number of motor main bodies 1X (i.e., the number of stages).

[0158] (Other embodiments) (1) In the fifth embodiment, the stator 10 and the rotor 20 are exposed to a vacuum in the hollow portion 70a of the housing 70 while operating. However, the present invention is not limited to this. The stator 10 and the rotor 20 may be exposed to an electrically insulating gas in the hollow portion 70a of the housing 70. The electrically insulating gas is a gas with high electrical insulation properties, such as sulfur hexafluoride (SF6). In this case, the hollow portion 70a of the housing 70 is filled with the electrically insulating gas. Therefore, the stator 10 and the rotor 20 are exposed to the electrically insulating gas in the hollow portion 70a of the housing 70 while operating. Alternatively, in the fifth embodiment, the stator 10 and the rotor 20 may be exposed to an electrically insulating liquid in the hollow portion 70a of the housing 70. For example, Fluorinert (registered trademark) is used as the electrically insulating liquid. In this case, the hollow portion 70a of the housing 70 is filled with the electrically insulating liquid. Therefore, the stator 10 and the rotor 20 operate while being exposed to the electrically insulating liquid in the hollow portion 70a of the housing 70. Similarly, in the first to fourth and sixth embodiments, the stator 10 and the rotor 20 may be exposed to an electrically insulating gas or an electrically insulating liquid.

[0159] (2) In the first embodiment, the electrostatic motor 1 is provided with 32 stator electrodes, i.e., stator electrodes 50a-50h, 51a-51h, 52a-52h, and 53a-53h. However, the number of stator electrodes used in the electrostatic motor 1 may be other than 32. Furthermore, in the second to eighth embodiments, the number of stator electrodes used in the electrostatic motor 1 may be one or more and is not limited to a predetermined number. Similarly, in the first to eighth embodiments, the number of poles is not limited to a predetermined number.

[0160] (3) In the first embodiment, the electrostatic motor 1 is provided with 24 stator electrodes, i.e., rotor electrodes 60a-60h, 61a-61h, and 62a-62h. However, the number of stator electrodes used in the electrostatic motor 1 may be other than 24. In the second to eighth embodiments, the number of rotor electrodes used in the electrostatic motor 1 may be one or more, and is not limited to a predetermined number.

[0161] (4) In the first embodiment, an example has been described in which the rotor 20 is disposed radially inward relative to the stator 10 and centered on the axis S. Alternatively, the rotor 20 may be disposed radially outward relative to the stator 10 and centered on the axis S in the electrostatic motor 1. Similarly, in the second to fourth embodiments, the rotor 20 is not limited to being disposed radially inward relative to the stator 10 and centered on the axis S in the electrostatic motor 1, and the rotor 20 may be disposed radially outward relative to the stator 10 and centered on the axis S.

[0162] (5) In the first embodiment, an example has been described in which n-channel MOSFETs are used as the transistors 30 and 31 in the inverter circuit 2 of the electrostatic motor 1. However, instead of this, various semiconductor elements other than n-channel MOSFETs, or various switches such as electromagnetic relays, may be used as the transistors 30 and 31. Similarly, in the second to eighth embodiments, various semiconductor elements other than n-channel MOSFETs, or various switches such as electromagnetic relays may be used as the transistors 30 and 31.

[0163] (6) In the above first to eighth embodiments, the stator 10 is described as being made of the base material 10a and the plating layer 10b. However, instead of this, the stator 10 may be made of a light metal material such as aluminum or a conductive material such as stainless steel. In this case, the stator 10 can be made lightweight by making the interior of the stator 10 hollow. Similarly, the rotor 20 is not limited to being made of the base material 20a and the plating layer 20b. The rotor 20 may be made of a light metal material such as aluminum or a conductive material such as stainless steel. In this case, the rotor 20 can be made lightweight by making the interior of the rotor 20 hollow.

[0164] (7) The present disclosure is not limited to the above-described embodiments and can be modified as appropriate within the scope of the claims. The above-described embodiments are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that the elements constituting the embodiments are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle. In the above-described embodiments, when numerical values ​​such as the number, values, amounts, and ranges of components of the embodiments are mentioned, they are not limited to the specific numbers unless they are specifically stated as essential or are clearly limited to a specific number in principle. In the above-described embodiments, when the shape, positional relationship, etc. of components are mentioned, they are not limited to the shape, positional relationship, etc. unless they are specifically stated or are clearly limited to a specific shape, positional relationship, etc. in principle. [Explanation of symbols]

[0165] 1. Electrostatic motor 2. Inverter circuit 10 Stator 20 rotors 30 transistors 31 Transistor 32 capacitor 33 Drive circuit 34 Rotation angle sensor 50a Stator electrode 60a rotor electrode

Claims

1. a stator (10) having a plurality of stator electrodes (50, 50a to 50h, 51a to 51h, 52a to 52h, 53a to 53h) arranged at equal intervals in a circumferential direction around an axis (S); a rotor (20) having a plurality of rotor electrodes (60a to 60h, 61a to 61h, 62a to 62h, 60) arranged at equal intervals in a circumferential direction around the axis, and configured to be rotatable relative to the stator in one direction of a rotation (Ka) around the axis; When one of the plurality of stator electrodes and the plurality of rotor electrodes is a plurality of one-side electrodes, and the other of the stator electrodes and the rotor electrodes other than the plurality of one-side electrodes is a plurality of other-side electrodes, a control unit (2) that sets the polarity of the plurality of one-side electrodes to either positive or negative polarity and sequentially switches the polarity of the plurality of other-side electrodes from one of the positive and negative polarities to the other polarity, thereby generating in the rotor a rotational torque that rotates the rotor in one direction of the rotation by an attractive force due to an electrostatic force generated between the plurality of rotor electrodes and the plurality of stator electrodes; An electrostatic motor comprising:

2. When a stator electrode located on one side in the rotational direction among two stator electrodes adjacent to each other in the rotational direction is defined as a one-side stator electrode, and a stator electrode located on the other side in the rotational direction among the two adjacent stator electrodes is defined as an other-side stator electrode, and a middle position between the one-side stator electrode and the other-side stator electrode in the rotational direction is defined as a rotational middle position (Zx), an angle sensor (34) for detecting angles of the plurality of rotor electrodes about the axis; the plurality of stator electrodes and the plurality of rotor electrodes are arranged at equal intervals in the circumferential direction, the plurality of stator electrodes are the plurality of one-side electrodes, and the plurality of rotor electrodes are the plurality of other-side electrodes; the polarity of each of the plurality of stator electrodes is set to negative by the control unit, when it is determined based on the angle detected by the angle sensor that the plurality of rotor electrodes are located within a first angle range (fb) centered on the axis between the rotational direction intermediate position and the one-side stator electrode, the control unit generates the rotational torque in the rotor by setting the polarity of the plurality of rotor electrodes to positive polarity; 2. The electrostatic motor according to claim 1, wherein, when it is determined, based on the angle detected by the angle sensor, that the plurality of rotor electrodes are located within a second angle range (fa) centered on the axis between the other-side stator electrode and the intermediate position in the direction of rotation, the control unit sets the polarity of the plurality of rotor electrodes to negative, thereby causing the rotor to rotate by inertia toward one side in the direction of rotation.

3. When a stator electrode located on one side in the rotational direction among two stator electrodes adjacent to each other in the rotational direction is defined as a one-side stator electrode, and a stator electrode located on the other side in the rotational direction among the two adjacent stator electrodes is defined as an other-side stator electrode, and a middle position between the one-side stator electrode and the other-side stator electrode in the rotational direction is defined as a rotational middle position (Zx), an angle sensor (34) for detecting angles of the plurality of rotor electrodes about the axis; the plurality of stator electrodes and the plurality of rotor electrodes are arranged at equal intervals in the circumferential direction, the plurality of stator electrodes are the plurality of one-side electrodes, and the plurality of rotor electrodes are the plurality of other-side electrodes; the polarity of each of the plurality of stator electrodes is set to positive by the control unit, Furthermore, when the control unit determines, based on the angle detected by the angle sensor, that the plurality of rotor electrodes are located within a first angle range (fb) centered on the axis between the rotational direction intermediate position and the one-side stator electrode, the control unit generates the rotational torque in the rotor by setting the polarity of the plurality of rotor electrodes to negative polarity; 2. The electrostatic motor according to claim 1, wherein, when it is determined, based on the angle detected by the angle sensor, that the plurality of rotor electrodes are located within a second angle range (fa) centered on the axis between the other-side stator electrode and the intermediate position in the direction of rotation, the control unit sets the polarity of the plurality of rotor electrodes to positive polarity, thereby causing the rotor to rotate by inertia toward one side in the direction of rotation.

4. When one of the plurality of stator electrodes, which is adjacent to one another in the rotational direction, is defined as a one-side stator electrode, and the other of the adjacent stator electrodes, which is adjacent to one another in the rotational direction, is defined as a other-side stator electrode, and when a middle position between the one-side stator electrode and the other-side stator electrode in the rotational direction is defined as a rotational middle position (Zx), an angle sensor (34) for detecting angles of the plurality of rotor electrodes about the axis; the plurality of stator electrodes and the plurality of rotor electrodes are arranged at equal intervals in the circumferential direction, the plurality of rotor electrodes are the plurality of one-side electrodes, and the plurality of stator electrodes are the plurality of other-side electrodes; the polarity of each of the plurality of rotor electrodes is set to negative by the control unit, when it is determined, based on the angle detected by the angle sensor, that the plurality of rotor electrodes are located within a first angle range (fb) centered on the axis between the rotational direction intermediate position and the one-side stator electrode, the control unit generates the rotational torque in the rotor by setting the polarity of the plurality of stator electrodes to positive; 2. The electrostatic motor according to claim 1, wherein, when it is determined, based on the angle detected by the angle sensor, that the plurality of rotor electrodes are located within a second angle range (fa) centered on the axis between the other-side stator electrode and the intermediate position in the direction of rotation, the control unit sets the polarity of the plurality of stator electrodes to negative, thereby causing the rotor to rotate by inertia toward one side in the direction of rotation.

5. When one of the plurality of stator electrodes, which is adjacent to one another in the rotational direction, is defined as a one-side stator electrode, and the other of the adjacent stator electrodes, which is adjacent to one another in the rotational direction, is defined as a other-side stator electrode, and when a middle position between the one-side stator electrode and the other-side stator electrode in the rotational direction is defined as a rotational middle position (Zx), an angle sensor (34) for detecting angles of the plurality of rotor electrodes about the axis; the plurality of stator electrodes and the plurality of rotor electrodes are arranged at equal intervals in the circumferential direction, the plurality of rotor electrodes are the plurality of one-side electrodes, and the plurality of stator electrodes are the plurality of other-side electrodes; the polarity of each of the plurality of rotor electrodes is set to positive by the control unit, when it is determined based on the angle detected by the angle sensor that the plurality of rotor electrodes are located within a first angle range (fb) centered on the axis between the rotational direction intermediate position and the one-side stator electrode, the control unit generates the rotational torque in the rotor by setting the polarity of the plurality of stator electrodes to negative; 2. The electrostatic motor according to claim 1, wherein, when it is determined, based on the angle detected by the angle sensor, that the plurality of rotor electrodes are located within a second angle range (fa) centered on the axis between the other-side stator electrode and the intermediate position in the direction of rotation, the control unit sets the polarity of the plurality of stator electrodes to positive polarity, thereby causing the rotor to rotate by inertia toward one side in the direction of rotation.

6. 2. The electrostatic motor according to claim 1, wherein, when the direction in which the axis extends is defined as the axial direction, the plurality of stator electrodes are respectively arranged so as to be shifted in the axial direction (Sz) relative to the plurality of rotor electrodes.

7. 2. The electrostatic motor according to claim 1, wherein the plurality of stator electrodes are respectively arranged so as to be shifted from the plurality of rotor electrodes in a radial direction (Cy) about the axis.

8. 2. The electrostatic motor of claim 1, wherein the plurality of stator electrodes each form an integral, unitary structure.

9. 2. The electrostatic motor according to claim 1, wherein each of said plurality of rotor electrodes is integrally formed into a single unitary structure.

10. The stator includes a plurality of stator support portions (11) to which one or more of the plurality of stator electrodes are connected, The rotor includes a plurality of rotor support portions (21) to which one or more of the plurality of rotor electrodes are connected, When a direction in which the axis extends is defined as an axial direction, the plurality of stator support portions are arranged in the axial direction and connected to each other, 2. The electrostatic motor according to claim 1, wherein the plurality of rotor support portions are aligned in the axial direction and connected to each other.

11. 2. The electrostatic motor of claim 1, wherein the plurality of stator electrodes and the plurality of rotor electrodes are each exposed to a vacuum.

12. 2. The electrostatic motor according to claim 1, wherein the plurality of stator electrodes and the plurality of rotor electrodes are exposed to an electrically insulating gas having electrical insulating properties.

13. 2. The electrostatic motor according to claim 1, wherein the plurality of stator electrodes and the plurality of rotor electrodes are exposed to an electrically insulating liquid having electrical insulating properties.

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