Electrical generator or motor structure – Dynamoelectric – Rotary
Patent
1997-08-08
1998-08-25
Laballe, Clayton E.
Electrical generator or motor structure
Dynamoelectric
Rotary
310261, H02K 2114, H02K 2112, H02K 127
Patent
active
057985901
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an electric motor having a spherical rotor which is able to rotate in a multi-degree-of-freedom.
2. Description of the Prior Art
As a prior art, there is one, for example, disclosed by the Japanese laid-open patent application No. Hei 5(1993)-64417, construction of which is shown in FIGS. 5 and 6. In FIG. 5, in an outer surface of a spherical rotor 1, which is hollow, a plurality of permanent magnets 2 are buried in a lattice state so that adjacent polarities are different from each other as shown in FIG. 6, and various detectors and the like 40 are provided within the spherical rotor 1.
On an outer side of the spherical rotor 1, there is provided a stator 3 with a certain space therefrom, and in a concave surface of the stator 3 which opposes the surface of the spherical rotor 1, a plurality of electromagnets are buried in a lattice state.
Numeral 5 designates a bearing which supports the spherical rotor 1 in a non-contact state. The bearing 5 causes the spherical rotor 1 to float by jetted gas supplied from a gas cylinder 6 via a pressure pipe 9.
Numeral 8 designates a controller, which functions to compute a respective size of components in a direction, .beta. direction and .gamma. direction in 3 axes orthogonal coordinates based on an actuation command (vector) for the spherical rotor 1, to compute a relative position of the permanent magnets 2 and the electromagnets based on an input of a current position in the .alpha. direction, .beta. direction and .gamma. direction from a sensor (not shown) and to excite the electromagnets of the stator 3 in a predetermined pattern to actuate the spherical rotor 1 to rotate in the .alpha. direction, .beta. direction and .gamma. direction with a time allotment proportional to the respective size of the components.
Also, the Japanese laid-open patent application No. Sho 59(1984)-17860 discloses projecting teeth consisting of a magnetic material which are provided in place of the above-mentioned permanent magnets. In this prior art, torque is obtained by an attractive force between electromagnets and magnetic substances and there is no need of changing an exciting direction of the electromagnets as in the above-mentioned prior art, thus the spherical rotor can be rotated only with "on-off" action of the electromagnets in accordance with a predetermined exciting pattern.
Further, as another prior art, the Japanese laid-open patent application No. Hei 6(1994)-253582 discloses an electric motor having a spherical rotor wherein projections of a magnetic substance are provided in a lattice state wherein each projection is provided at each apex of a plurality of objects having triangular planes inscribing a spherical enveloping surface of the spherical rotor.
Also, in U.S. Pat. No. 5,413,010, an electric motor in which permanent magnets are arranged in a lattice state on a surface of a spherical rotor is disclosed, and an art in which an electric motor having the same kind of spherical rotor is applied to a control moment gyro is disclosed in U.S. Pat. No. 5,476,018 and a similar example applied to an agitator is disclosed in U.S. Pat. No. 5,542,762, respectively.
In the above-mentioned prior art, there is a problem in that, as the permanent magnets 2 and the like are arranged on the outer surface of the spherical rotor 1 and the pitch between the permanent magnets becomes inevitably narrow in the vicinity of the pole and further as the pitch between the permanent magnets in the direction of 2 orthogonal axes and that in the oblique direction are largely different from each other, a large variation and irregularity in the torque generated by the excitation of the electromagnets occurs.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a multi-degree-of-freedom electric motor which is able to obtain a uniform torque and which is able to perform a fine and smooth rotational control.
In order to attain the afore-mentioned object, the present inventio
REFERENCES:
patent: 4661737 (1987-04-01), Barri
patent: 4739241 (1988-04-01), Vachtsevanos et al.
patent: 5204573 (1993-04-01), Bederson et al.
patent: 5413010 (1995-05-01), Nakanishi et al.
LaBalle Clayton E.
Mitsubishi Jukogyo Kabushiki Kaisha
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