Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
1999-12-09
2001-05-22
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S254100, C310S162000
Reexamination Certificate
active
06236135
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a structure of a toroidal core type actuator and more particularly the stator structure of the toroidal core type actuator which facilitates winding and mounting and enables reduction in costs.
2. Description of the Prior Art
A toroidal core type actuator is designed so that rotating shaft operates in repetitive rotary motions. While the repetitive rotary motions are within range of 180° (±90°), it is desired to produce constant torques in the range of the operational angle. In other words, the actuator is required for characteristics that the torques produced have no angle dependence at identical currents. With this view, so-called toroidal core type actuator constitution is typically employed in which wires are wound in coils about the circumference of a hollow cylindrical core to prepare a stator and a rotor comprising a permanent magnet is rotatably arranged in the hollow cylindrical core via a minute air gap.
However, since the hollow cylindrical core is used as the winding core when winding the coils about the circumference thereof, a special winding machine is naturally required for the toroidal core type actuator. This not only causes complication of the winding process, but also produces a drawback that collapse of the convolutions of the coils, and terminal handling after winding, positioning of the stator and the rotor after winding, fixing thereof and the like become problems to hamper stable constitution of the stator unit with excellent working properties.
Moreover, since the hollow cylindrical core requires a constant permeance (reciprocal of reluctance) along the circumferential direction, high dimensional accuracies are needed of the core. On this account, the stator is constituted by machining a block material, or by punching flat rolled soft magnetic steel strips having insulated surfaces into a disc shaped one under a press and then laminating the same in an axial direction. The machining, while securing high dimensional accuracies, produces a problem in increasing work costs. The lamination method requires expensive molds, and has problems in caulking accuracies and the like. Thus, there has been needed a stator structure which can be constituted at lower costs.
SUMMARY OF THE INVENTION
In view of the foregoing, an object of the present invention is to provide a toroidal core type actuator having a stator unit which is increased in winding density, is improved in terminal handling after winding, positioning of the stator after winding, and fixing of the same, and is excellent in working properties.
To achieve the foregoing object, the present invention provides a toroidal core type actuator comprising a stator and a rotor, the stator having winding in coils applied to a hollow cylindrical core composed of soft magnetic material, the rotor comprising a permanent magnet having N poles and S poles alternately arranged in total of m in the circumferential direction thereof, the rotor being rotatably arranged in the core of the stator via a minute air gap, wherein: m of phase separators composed of non-magnetic material are arranged on the peripheral surface of the hollow cylindrical core so as to be separated from each other by 360°/m; and the winding is applied to winding regions separated from each other by the phase separators.
The phase separators are preferably composed of insulating resin.
It is preferable that the m of phase separators arranged on the hollow cylindrical core are identical to each other in dimension at the radial innermost portions thereof, and the dimension is set to be smaller than the radial innermost dimension of the coils wound on the core.
It is also preferable that the m of phase separators arranged on the hollow cylindrical core are identical to each other in dimension at the outermost radial portions thereof, and that the dimension is set to be greater than the outermost radial dimension of the coils wound on the core.
Besides, it is preferable that the phase separators are integrally provided with an insulating portion for electrical insulation between the core and the winding.
Moreover, it is also preferable that at least one of the phase separators is provided with one or more coil binding terminal(s).
The core is preferably constituted by rolling a soft magnetic thin strip of uniform width into a roll shape.
The soft magnetic thin strip of roll shape preferably has a tapered portion sequentially and successively increasing its width from the innermost peripheral end thereof at the start of the roll.
The tapered portion is preferably extended for approximately one turn along the innermost periphery of the core.
Furthermore, it is preferable that the hollow cylindrical core is constituted by preparing pipe-shaped soft magnetic material as a rolling core, and winding thereon the soft magnetic thin strip of uniform width into a roll shape.
The nature, principle and utility of the invention will become more apparent from the following detailed description when read in conjunction with the accompanying drawings
REFERENCES:
patent: 4363988 (1982-12-01), Kliman
patent: 4563606 (1986-01-01), Fukasawa et al.
patent: 5304883 (1994-04-01), Denk
Fujitani Sakae
Harada Naoyuki
Ishii Takashi
Suzuki Yuzuru
Fay Sharpe Fagan Minnich & McKee LLP
Minebea Co. Ltd.
Perez Guillermo
Ramirez Nestor
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