JPH09158994A - Electromagnetic actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a structure and to obtain stable torque. SOLUTION: An electromagnetic actuator is constituted by providing a fixed internal gear 6 fixed to a fixed member 1, rotary internal gear 7 with a number of teeth slightly different from the fixed internal gear 6, external gear 2 meshed with both the fixed/rotary internal gears 6, 7, stator 3 provided in the fixed member 1 and a rotor provided in the external gear 2 to be opposed to the stator 3 through a cavity. Here, the external gear 2 is fixed to a rotary shaft 21 rotatably supported to the fixed member 1, further so as to mesh with both the fixed/rotary internal gears 6, 7 through a plurality of planet gears 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetic actuator that produces high torque at low speed.

[0002]

2. Description of the Related Art Conventionally, as an electromagnetic actuator for rotating a rotary shaft at a low speed, two internal gears having the same number of teeth are provided on two fixing members supporting both ends of a crank shaft of an eccentric differential planetary mechanism, A rotating member having an internal gear with a slightly different number of teeth from the internal gear provided on the fixing member is provided between the two fixing members, and the crank pin of the crankshaft meshes with the internal gear provided on the fixing member. In addition, a pinion that also meshes with the internal gear provided on the rotating member is supported, and a stator composed of a plurality of coils is provided on the surface of the fixed member facing the pinion, and the side surface of the pinion is made of electromagnetic soft iron facing the stator. A rotor composed of radial grooves is provided. With such a configuration, by exciting the stator, the pinion is rotated, and the rotating member is decelerated and rotated at a rotational speed according to the difference in the number of teeth of the fixed member meshing with the pinion and the internal gear of the rotating member. Have been disclosed (for example, Japanese Patent Laid-Open No. Sho 6).
No. 3-224649).

[0003]

However, in the above prior art, since the pinion is supported by the crank pin of the crankshaft, the rotor provided on the pinion swings with respect to the fixed member supporting the crankshaft. Since the relative position in the radial direction with respect to the stator constantly fluctuates, there are problems that torque fluctuations and vibrations occur in the main body, and that the structure is complicated and the manufacturing cost increases. An object of the present invention is to provide an electromagnetic actuator having a simple structure and capable of obtaining stable torque.

[0004]

In order to solve the above problems, the present invention provides a fixed internal gear fixed to a fixing member,
A rotary internal gear whose number of teeth is slightly different from the fixed internal gear, an external gear that meshes with both the fixed internal gear and the rotary internal gear, and a surface of the fixed member that faces the external gear. In an electromagnetic actuator comprising a stator provided on the external gear and a rotor provided on the external gear and facing the stator via an axial gap, the external gear is rotatable on the fixed member. It is fixed to a rotating shaft supported by and is meshed with both the fixed internal gear and the rotating internal gear via a plurality of planetary gears. The external gear is made of a non-magnetic material,
And a rotor provided with a permanent magnet having a plurality of magnetic poles facing the stator on the side surface of the external gear, or having a plurality of magnetic poles facing the stator,
The planetary gear is made of a non-magnetic material.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to embodiments shown in the drawings. 1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is a front sectional view taken along the line AA. In the figure, reference numeral 1 denotes two disk-shaped fixing members facing each other, which are fixed to a base 12 via two supporting members 11. Reference numeral 2 denotes an external gear fixed to the rotary shaft 21 and is made of a nonmagnetic metal such as stainless steel, a nonmagnetic metal such as titanium or aluminum alloy, or a tensile strength resin such as nylon having lubricity such as molybdenum sulfide. And is supported via a pivot bearing 13 provided at the center of the fixed member 1. Reference numeral 22 is a permanent magnet 22 having a magnetic pole on the axial end surface concentric with the rotating shaft 21, and is, for example, SmCo or N.
The external gear 2 and the permanent magnet 22 are made of a rare earth element such as dFeB, and the magnetic poles are exposed on both end surfaces of the external gear 2 so that a plurality of magnetic poles are arranged at equal intervals in the circumferential direction. The rotor 20 is formed by. Reference numeral 3 denotes a stator provided so as to face the permanent magnet 22 of the fixed member 1 with an air gap in the axial direction. The stator 3 is formed by winding a stator coil 32 around a magnetic pole portion 31, and the magnetic pole portion 31 is an external gear. The second permanent magnet 22 is opposed to the second permanent magnet 22 with a gap. Reference numeral 4 denotes a support disk supported on the outer circumferences of both fixing members 1 so as to be rotatable via bearings 41. Reference numeral 5 denotes three planetary gears meshing with the external gear 2. Are divided into three equal parts and are supported by pivot bearings 42, respectively. Two fixed internal gears 6 mesh with the planetary gears 5 and are fixed to the base 12. Reference numeral 7 is a rotating internal gear having a number of teeth slightly different from that of the fixed internal gear 6 but having the same module and arranged so as to mesh with the planetary gear 5. Gear 5
Has been bitten. A V-shaped groove 71 is formed on the outer circumference of the rotating internal gear 7 to transmit torque to the outside, and a V-belt is wound around the V-shaped groove 71.

The operation of the electromagnetic actuator having the above structure will be described below. When the stator 3 is excited by the stator coil 32, the external gear 2 provided with the permanent magnet 22 moves to the rotary shaft 21.
Rotate around the axis. When the external gear 2 rotates, the planetary gear 5 meshes with the fixed internal gear 6 and revolves inside the fixed internal gear 6 while rotating. At this time, the rotary internal gear 7 also meshes with the planetary gear 5, but since the number of teeth is slightly different from the fixed internal gear 6, the number of teeth of the fixed internal gear 6 and the number of teeth of the rotary internal gear 7 are different. The rotating internal gear 7 is decelerated and rotates at a rotation speed according to the difference between In this case, since the external gear 2 is provided with the permanent magnet 22 having magnetic poles on the axial end surface concentric with the rotating shaft 21, the external gear 2 is excited by exciting the stator 3 facing the permanent magnet 22. Rotates without eccentricity. Therefore, fluctuations in torque and vibrations in the main body do not occur. In the above embodiment, the example in which the permanent magnet is embedded in the external gear is described, but the material of the external gear is a permanent magnet having a high magnetic flux density such as rare earth, and a plurality of magnetic poles in the circumferential direction. The planetary gears may be magnetized so as to have different polarities, and the planetary gear may be made of a nonmagnetic metal such as stainless steel, titanium, or an aluminum alloy, or a nonmagnetic material such as a resin having lubricity. As a result, it is possible to configure a microminiature electromagnetic actuator that does not require lubricating oil and has a long life.

[0007]

As described above, according to the present invention, the external gear is provided with the permanent magnet having the magnetic pole on the axial end surface concentric with the rotating shaft, and the stator provided on the fixing member is excited. Since the external gear is rotated without eccentricity, it is possible to provide an electromagnetic actuator that does not have a difficult element such as a crankshaft and that has a simple structure and can obtain a stable torque.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an embodiment of the present invention.

FIG. 2 is a front sectional view taken along the line AA showing the embodiment of the present invention.

[Explanation of symbols]

1: fixed member, 11: support member, 12: base, 13,
42: Pivot bearing, 2: External gear, 20: Rotor, 2
1: rotating shaft, 22: permanent magnet, 3: stator, 31: magnetic pole part, 32: stator coil, 4: supporting disc, 41: bearing,
5: planetary gear, 6: fixed internal gear, 7: rotating internal gear,
71: V groove

Claims (3)

[Claims] 1. A fixed internal gear, which is fixed to a fixing member,
A rotary internal gear whose number of teeth is slightly different from the fixed internal gear, an external gear that meshes with both the fixed internal gear and the rotary internal gear, and a surface of the fixed member that faces the external gear. In an electromagnetic actuator comprising a stator provided on the external gear and a rotor provided on the external gear and facing the stator via an axial gap, the external gear rotates on the fixed member. An electromagnetic actuator, which is fixed to a freely supported rotating shaft and meshes with both the fixed internal gear and the rotating internal gear via a plurality of planetary gears. 2. The external gear is made of a non-magnetic material,
The electromagnetic actuator according to claim 1, further comprising a rotor formed of a permanent magnet having a plurality of magnetic poles facing the stator, on a side surface of the external gear. 3. The external gear has a plurality of magnetic poles facing the stator and is made of an integral permanent magnet that constitutes a rotor, and the planetary gear is made of a non-magnetic material. Electromagnetic actuator.