WO2002069475A1 - Electric motor - Google Patents

Abstract

The invention relates to an electric motor comprising a rotor in the form of a smooth ferromagnetic cylinder (1). Said motor also comprises a stator consisting of one or more poles (2) which can move slightly at periodic intervals according to a determined cycle. When a periodic current is supplied to said poles, they exert a periodic electromagnetic force of attraction on the rotor and move it a fraction of a turn. When the current is stopped, a recall system (3) is provided to return each pole to a previous position. In this way, low rotation speeds, a fraction of a turn and a high torque can be performed with a simple, robust and economical design. The rotor can be placed inside or even around the stator and it can be disposed axially or radially opposite the stator.

Description

 Electric motor

The present invention relates to an electric motor whose use is particularly recommended in the case of rotation at very low speed, safe and precise positioning, a motor used to exert a torque.

The rotation of conventional motors required the presence of an electrical circuit or permanent magnet in the rotor, and sometimes the use of reducer. This leads to additional costs and complications in manufacturing and maintenance.

This electric motor makes it possible to achieve low rotational speeds, high torque, and precise steps and of very low amplitude with a simple, robust, economical and maintenance-free design, applicable to wide ranges of powers.

The operation of this motor is based on the principle of magnetic attraction between the two moving, not parallel, rotor surfaces and those of the poles which constitute, during operation, a variable air gap. According to a first characteristic, it in fact comprises a rotor in the shape of a cylinder or smooth ferromagnetic cone and one or more poles fixed in a flexible manner to the stator, where each pole is capable of carrying out a cycle of periodic movement which can be a translation along an axis perpendicular or inclined to the axis of rotation or a rotation of a small angle about an axis parallel or inclined to the axis of rotation or a combination of these movements.

Each pole must be equipped with a reminder system, and powered by a periodic current. There is very little periodic movement of the poles, causing the rotor to rotate by direct or indirect friction. The arrangement of the poles relative to the radial axis of the rotor determines the direction of rotation of the motor. This principle applies to designs where the rotor is placed inside or around the stator or else disposed axially or radially opposite the stator. According to the particular embodiments: The rotor can be a cylinder or a smooth or toothed ferromagnetic cone.

The poles are fixed flexibly to the stator and, provided with a return system to an earlier position.

These poles can be in the form of I, U or E, depending on the arrangement of the coils.

The accompanying drawings illustrate the invention:

Figure 1 shows in section an embodiment of the invention with a smooth rotor. Figure 2 shows in section a second embodiment of the invention with a toothed rotor.

With reference to these drawings, the electric motor comprises a cylindrical rotor (1) and several poles (2) fixed to the stator (6), by a distortion axis (3), which acts as a spring. The supply of the coils by a periodic current causes an electromagnetic attraction force which drives the poles in the direction (7) in periodic movement and the rotor in a rotation of a fraction of a turn.

In the embodiment according to FIG. (2), the rotor (1) has teeth (5), in fact the periodic movement of each pole drives the teeth of the rotor, without friction, by a corresponding angle in the direction ( 7).

The periodic current can be impulsive alternating single-phase, two-phase, three-phase ...

Claims

1 - An electric motor characterized in that the rotor is in the form of a cylinder (1) or a smooth or toothed ferromagnetic cone (5) and must not contain any electrical circuit or permanent magnet. 2- An electric motor characterized in that each pole (2) can perform a movement of very small amplitude, according to the embodiments, this movement is a translation along an axis perpendicular or inclined to the axis of rotation or a rotation d '' a small angle around an axis parallel or inclined with respect to the axis of rotation or a combination of these movements. 3- An electric motor according to claim (2) characterized in that each pole (2) is provided with a return system (3) which ensures its return to a previous position. 4- An electric motor according to claims 1, 2, 3 above characterized in that the surfaces of the poles (2) and the rotor (1) are not parallel during rest 5- An electric motor according to claims 1, 2 above characterized in that each pole (2) exerts a periodic pushing force, by friction, on the rotor to drive it in rotation. 6- An electric motor characterized in that each pole drives the teeth of the toothed rotor without friction. 7- An electric motor characterized in that the relative position of the poles with respect to the axis of rotation determines the direction of rotation. 8- An electric motor according to claim 4 characterized in that the surfaces of each pole with that of the rotor form a small angle which decreases slightly during the attraction between these surfaces, which forms a variable air gap. 9- An electric motor according to claim 7 characterized in that the direction of rotation can be changed by feeding the poles located in the opposite position.