JPH03183353A - Variable gap type motor - Google Patents

Abstract

PURPOSE:To obtain a motor of large torque by engaging a cylindrical circular spline and a flexible flex spline with each other, and deforming said flexible flex spline by magnetic force. CONSTITUTION:The principle of a harmonic speed reduction mechanism is applied to a motor. This is equipped with a cylindrical circular spline 1 equivalent to an internal gear and a cylindrical flex spline 2 equivalent to a flex ring. Furthermore, a plastic magnet 3 and a stator 4 are provided. Ther circular spline 1 has a spline tooth of specified pitch inside. The flex spline 2 is made of flexible material, and has spline teeth, which engage with the teeth fo the circular spline 1, at the periphery. The plastic magnet 3 has a magnetic pole in accord with each salient pole of the stator 4. When the salient poles are excited in order, the flex spline 2 is transformed, and rotates.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to electric motors, and more particularly to motors that generate large torque at low speeds.

2. Description of the Related Art Conventional motors are fixed-gap type motors in which the gap between the stator and rotor is constant, and utilize the tangential force generated by changes in the permeance of the gap.

That is, the permeance of the void is P, and the cross-sectional area of the void is L-X.
(L: Length of the air gap in the motor axis direction, x: Length of the air gap in the rotor rotation direction), where the air gap length is g and the vacuum permeability is μ, the permeance P of the air gap is calculated using the following equation (]). It is expressed as

P-μ・L-x/g... (1) Ordinary fixed-gap motors use the tangential force generated by dP/dx (change in the cross-sectional area of the air gap), but it is difficult to generate efficient force. In order to do this, the ratio of the gap g to the displacement ΔX (change in the cross-sectional area of the gap) must be on the order of several dozen.

Problem to be Solved by the Invention Rather than generating force by changing the cross-sectional area of the gap, that is, by the displacement ΔX, it is better to change the gap g and the displacement ΔX.
If the ratio of X is on the order of tens of tens, it is possible to generate tens of forces.

Therefore, an object of the present invention is to change the gap g to
There is provided a variable gap type motor that generates a large torque using a variable gap force of P/d g.

Means for Solving the Problems A cylindrical circular spline having teeth at a predetermined pitch on its inner peripheral surface, and teeth of the circular spline installed inside the circular spline and having teeth on its outer peripheral surface at the same pitch as the predetermined pitch. a cylindrical flexible flex spline provided with a smaller number of teeth; a cylindrical flexible plastic magnet disposed inside the flex spline and fixed non-rotatably in the circumferential direction; , and a stator having a plurality of salient poles on the outer periphery disposed inside the plastic magnet and wound with windings, the flexible plastic magnet having different magnetic poles alternately corresponding to each of the salient poles. The windings of the two salient poles arranged in the diametrical direction of the stator are excited by passing a current through them, displacing the plastic magnet and the flex spline outward, and furthermore, the two salient poles are perpendicular to the two salient poles. is excited to displace the plastic magnet and flex spline inward, the teeth of the flex spline and circular spline are engaged, and the flex spline is rotated by rotating the salient poles in sequence to generate large torque. I did it like that.

Operation The two diametrical salient poles of the stator are excited to repel the plastic magnets and displace them outward. Further, two salient poles perpendicular to the two diametrical salient poles are excited to absorb the plastic magnet and displace it inward. As a result, the flex spline disposed on the outside of the plastic magnet changes with the displacement of the plastic magnet, and the teeth of the flex spline and the teeth of the circular spline mesh at the outwardly displaced portion of the plastic magnet. By sequentially rotating the excitation of the salient poles, the positions where the teeth of the flex spline and the teeth of the circular spline mesh are sequentially rotated. Since the number of teeth of the flexspline is smaller than the number of teeth of the circular spline, when the salient pole is excited for one rotation, the flexspline moves and rotates by the difference in the number of teeth. By using this flex spline as an output shaft and extracting its rotation, a motor with high torque can be obtained.

Embodiment The present invention is a motor to which the principle of a harmonic reduction mechanism is applied. Therefore, first, the operating principle of the harmonic reduction mechanism will be explained.

FIG. 4 is a diagram showing the basic structure for explaining the principle of the harmonic reduction mechanism. A flex ring 101 is provided inside the internal gear 100 and has teeth having the same pitch as that of the internal gear 100. Inside the flex ring 101 is an elliptical ring drive shaft (wave generator ) 102 are provided. The number of teeth of the flex ring 101 is smaller than the number of teeth of the internal gear 100. For example, if the gear of the internal gear 100 is rioOJ, the number of teeth of the flex ring 101 is "98". The flex ring 101 is flexible and is an oval ring long sleeve part of the drive shaft 102 inscribed inside the flex ring 10.
The No. 1 tooth meshes with the internal gear 100. Therefore, when the elliptical ring drive shaft 102 is rotated, the meshing portion between the flex ring lO1 and the internal gear 100 moves and rotates.

The number of teeth of the flex ring 101 is smaller than the number of teeth of the internal gear 1-00, and the pitch of both teeth is the same, so when the elliptical ring of the drive shaft 102 rotates once, the flex ring 101 has a smaller number of teeth than the internal gear 1-00. It will move and rotate by the difference. In the previous example, it will rotate by 2 (=100-98) pitches. In this way, the drive shaft 1 which is the input shaft
Flex ring 1 of the output shaft by decelerating the rotation of 02,
It is designed to be taken out from 01.

The present invention constitutes a motor by replacing the drive shaft 102 with a permanent magnet and a stator in the harmonic reduction mechanism described above.

Fig. 3 is a sectional view of a variable gap type motor according to an embodiment of the present invention, and reference numeral 1 indicates an internal gear 100 of a harmonic reduction mechanism.
A corresponding cylindrical circular spline is provided with spline teeth at a predetermined pitch on the inside (the teeth are not shown in the figure).

Code 2 is the flex ring 10 of the harmonic reduction mechanism.
This is a cylindrical flex spline corresponding to No. 1, which has spline teeth (the teeth are omitted in the figure) on its outer periphery that mesh with the teeth of the circular spline, and is made of a flexible material. Further, the number of teeth of the flex spline is smaller than the number of teeth of the circular spline, and the pitch of the teeth is formed to be the same as the pitch of the teeth of the circular spline. Reference numeral 3 denotes a cylindrical plastic magnet inscribed in the flex spline 2, and a stator 4 is fixed inside the plastic magnet 3.

In this embodiment, the stator 4 has an eight-pole structure with two-phase drive, U phase and (The description of this winding is omitted.)

The above-mentioned plastic magnets 3 are arranged so that their magnetic poles are alternately different in accordance with each salient pole of the stator 4, and since they are plastic magnets, they have flexibility. Further, position sensors 5a and 5b for detecting the amount of deformation of the flex spline 2 are attached to the circular spline 1 with a phase difference of 90 degrees.

Circular spline 1. The stator 4 is fixed, and the plastic magnets are fixed so that they cannot rotate.

Therefore, current is passed through the U-phase winding and the U-phase salient pole U' U
When excited, depending on the direction of excitation, the
), as shown in (B), plastic magnet 3. The flexspline 2 produces two types of displacement.

That is, two U-phase salient poles U' arranged in the diametrical direction
When a current is passed through the winding so that Ll' is magnetized to the north pole and the salient poles U- and U- of the U phase in the direction orthogonal to these two salient poles are magnetized to the south pole, the result is shown in Fig. 2 (A). As shown in , the salient poles U', U
' repels the plastic magnet 3, displacing the plastic magnet 3 and the flex spline 2 circumscribing the plastic magnet outward, and the salient poles U-, U- absorb the plastic magnet 3, and the plastic magnet 3.' Displace the flexspline 2 inward. As a result, the plastic magnet 3 and the flex spline 2 have an elliptical shape, and the teeth of the flex spline 2 and the teeth of the circular spline 1 mesh with each other at the portion of the salient pole U"U" displaced outward.

Also, when the U phase is excited in the opposite direction, the plastic magnet 3 and the flex spline 2 change outward at the salient poles U-, U- of the U phase, as shown in FIG. 2(B), and the flex spline 2 The teeth of the circular spline 1 will mesh with each other.

On the other hand, when the ■ phase is excited, the two V-phase salient poles in the diametrical direction generate the plastic magnet 3. The flex spline 2 is displaced outwardly, and the flex spline 2 is
Plastic magnet with two V-phase salient poles3. When flexspline 2 is displaced inward, flexspline 2
is the portion displaced outward, and the teeth of the flex spline 2 and the teeth of the circular spline 1 mesh with each other.

In addition, Fig. 2 (A), (B), and Fig. 3 (A).

In (B), only the winding of the salient pole to be excited is shown, and
Arrow 6 indicates the direction of magnetic flux.

Therefore, if the U phase is excited to bring it into the state shown in Figure 2 (A), and then the V phase is excited to bring it into the state shown in Figure 3 (A), the teeth of flex spline 2 and the teeth of circular spline ■ will be connected. The meshing position is from the position shown in Figure 2 (A) to Figure 3 (A).
The position changes to the position shown in .

Furthermore, when changing the meshing position of the teeth of the flex spline 2 and the teeth of the circular spline 1 from the state shown in Fig. 2 (A) to the state shown in Fig. 3 (A), the values of the excitation currents of the U phase and ■ phase If the U-phase and ■-phase are simultaneously excited by changing the angle, the meshing position of the teeth of the flex spline 2 and the teeth of the circular spline 1- will continuously move from FIG. 2(A) to FIG. 3(A).

Thereafter, the U phase is similarly excited from the state shown in Fig. 3 (A) to the state shown in Fig. 2 (B), and then the state shown in Fig. 3 (B) is changed to
The phase is energized, and then the U phase is energized to the state shown in FIG. 2(A). Below, phase ■ and U phase are excited while changing the forward excitation direction,
Figure 2 (A).

If the excitation state is changed from Fig. 3 (A), Fig. 2 (B), and Fig. 2 (A), the meshing position of the teeth of flex spline 2 and circular spline will sequentially move clockwise. becomes. When the meshing position has rotated once, the flexspline 2 rotates by the difference between the number of teeth of the circular spline 1 and the number of teeth of the flexspline 2. For example, if the number of teeth of the circular spline 1 is rl 00J and the number of teeth of the flexspline 2 is "98", the flexspline 2 will rotate with only 2 (100-98) pitches.

In addition, to rotate in the opposite direction, from the state shown in Fig. 2 (A) to Fig. 3 (B), Fig. 2 (B), Fig. 3 (A), Fig. 2 (
A) The excitation state may be changed sequentially.

If the rotation is extracted using the flex spline 2 as an output shaft, a large torque motor can be obtained.

Therefore, a position sensor installed in the circular spline 1 detects the amount of deformation of the flex spline 2, detects the state of the flex spline 2, and a processor that controls the motor issues commands such as the generated torque in the rotation direction 9. If we calculate the following deformation state of the flexspline according to the following and apply current to the windings of each phase and perform excitation control,
The rotation of the flex spline 2 can be controlled in any direction.

Effects of the invention The present invention provides a stator and a rotor (flex spline).
Since the gap between the motors is made variable and the change in permeance caused by the change in the gap is extracted as force, it is possible to generate torque several tens of times as much as a conventional motor.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention, FIG. 2(A),
(B) is a diagram showing the U-phase excitation state in the same embodiment, Figures 3 (A) and (B) are diagrams showing the V-phase excitation state in the same embodiment, and Figure 4 explains the principle of the harmonic reduction mechanism. FIG. 2 is a diagram showing the basic structure for DESCRIPTION OF SYMBOLS 1... Circular spline, 2... Flex spline, 3... Plastic magnet, 4... Stator, 5a, 5b... Position sensor. 4th Curse Figure 0 (81 3rd 吃(A) Graph (B)

Claims (2)

[Claims] (1) A cylindrical circular spline with teeth at a predetermined pitch on the inner peripheral surface, and a circular spline arranged inside the circular spline and having teeth on the outer peripheral surface with the same pitch as the predetermined pitch but less than the number of teeth of the circular spline. a cylindrical flexible flex spline provided with several teeth; a cylindrical flexible plastic magnet disposed inside the flex spline and fixed non-rotatably in the circumferential direction;
and a stator having a plurality of salient poles disposed inside the plastic magnet and wound with windings on the outer periphery, and the flexible plastic magnet has different magnetic poles alternately arranged corresponding to each of the salient poles. , current is applied to the windings of at least two diametrical salient poles of the stator to excite them, displacing the plastic magnet and the flex spline outward so that the teeth of the flex spline and the circular spline are engaged, and the windings of the two salient poles of the stator are excited. A variable gap type motor that rotates a flex spline by sequentially rotating and moving excitation. (2) Excite the two diametrical salient poles to displace the plastic magnet and flex spline outward, and excite the two salient poles orthogonal to the above two salient poles to move the plastic magnet and flex spline inward. The variable gap type motor according to claim 1, wherein the variable gap type motor causes displacement.