JPH0217246A - Harmonic gearing device using permanent magnet - Google Patents

Abstract

PURPOSE:To aim at weight reduction of the title device by fitting the first group and the secondary group of permanent magnets both poles of which are continued alternatively at the exterior circumference of a rotor arranged inside a flexible gear and the interior circumference of the flexible gear and deforming the flexible gear ovally by adsorbing force and resiliency between both poles. CONSTITUTION:Permanent magnet pieces 3 are continuously arranged at equal intervals at the interior circumference of a flexible outer gear 2 to arrange N pole and S pole alternatively, N pole and S pole of permanent magnet pieces 4 are alternatively arranged to be faced to the permanent magnet pieces 3 at the exterior circumference of a rotor 5 arranged inside the flexible outer gear 2. Same poles are arranged to be faced each other in the radial direction of the rotor 5 and the permanent magnets 3, 4 are arranged to make N pole and s pole faced each other in a crossing direction to a. Accordingly, the flexible outer gear is deformed ovally, only the oval can be rotated with keeping oval. A wave generator becomes unnecessary in the harmonic gearing device by this construction so that weight reduction can be achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a harmonic gear device, and particularly to a harmonic gear device that utilizes the attractive force and repulsive force of permanent magnets.

[Prior Art] A typical harmonic gear device includes a rigid circular internal gear, which is provided inside the circular internal gear, is deformed into an elliptical shape so as to mesh with the circular internal gear at three points, and has a number of teeth equal to the number of teeth inside the circular gear. 2h more teeth than the number of gear teeth (h is a positive integer.

The same applies hereinafter) a small number of flexible external gears;
a wave generator that fits inside the visible external gear to deflect the flexible external gear in an elliptical shape; The outer ring of the ball bearing is fitted into a flexible external gear (the principle of operation of the 1mm face gear device is described in the applicant's patent application A. 62-316999).

In a harmonic gear device with such a configuration, when the input shaft provided on the cam plate of the wave generator is rotated, the elliptical shape of the flexible external gear is rotated, and the rotation of this elliptical shape causes both gears to move their teeth. When a circular internal gear or a flexible external gear is provided with an output shaft, the output shaft rotates at a large reduction ratio with respect to the input shaft. As described above, harmonic gear systems are often used in precision machinery and the like because they can provide a large reduction ratio with a small number of components.

This harmonic gear device consists of a flexible external gear formed into a cup shape and the entire device shaped like a cup, and two flat internal gears arranged side by side on the outside of the annular external gear. There is a generally flat type in which one internal gear has 2h more teeth than the external gear and the other internal gear has the same number of teeth as the external gear.

Note that, as a harmonic gear device, there is also one in which a rigid circular gear is used as an external gear and a flexible gear is used as an internal gear, and the operating principle is the same.

(IO to be Solved by the Invention) As mentioned above, the wave generator consists of an oval cam plate and a flexible ball bearing on the outer periphery of the cam plate. The flexible external gear is bent into an elliptical shape, and only the elliptical shape is rotated to relatively rotate the circular internal gear and the flexible external gear.

Wave generators with this structure require a special flexible ball bearing on the outer periphery of the cam plate, which increases the inertial mass of the entire device, resulting in poor response characteristics and also makes the entire device expensive. . Furthermore, in this harmonic gear system, flexible ball bearings determined the life of the system, and lubrication required careful consideration.

The presence of this wave generator is largely responsible for limiting the input rotational speed and reducing mechanical efficiency.

The purpose of the present invention is to solve the problems caused by using conventional wave generators by creating a harmonic structure that can hold flexible gears in an elliptical shape without contact using the magnetic force of permanent magnets. The purpose is to realize a gear device.

(Means for Solving the Problems) In order to achieve the above object, the harmonic gear device according to the present invention utilizes the attractive force generated between the same poles of permanent magnets and the repulsive force generated between different poles instead of the wave generator. hand,
The flexible gear is deformed into a desired shape.

For this purpose, in the present invention, as shown in FIG.
The rotor (
On the outer periphery of the disk-shaped (disk-shaped object) 5 arranged concentrically with the input shaft, permanent magnet pieces 4 are placed so as to face the permanent magnet pieces 3 so that the north and south poles alternate. Arrange continuously at approximately equal intervals. Permanent magnet north and north poles or south and south poles
The poles repel each other, and the N and S poles attract each other. Therefore, at both ends of the - diameter direction a of the rotor 5, the permanent magnet pieces are arranged so that the N poles and the N poles or the S poles and the S poles face each other. 3 and 4 are arranged, and the permanent magnet pieces 3 are arranged such that the N pole and the S pole face each other at both ends of the diameter direction perpendicular to the diameter direction a.
and 4, a repulsive force acts in the a direction,
An attractive force acts in the b direction. As a result, the shape of the flexible external gear 2 can be deformed into a substantially elliptical shape with the long axis in the a direction and the short axis in the b direction.

This deformation of the flexible external gear 2 into an elliptical shape must be maintained even when the rotor 5 rotates. For this reason, the rotor 5
The number of magnets is 2n (n is a positive integer of 2 or more. The same applies hereinafter)
By setting the number of magnets in the flexible external gear 2 to either 2n-4 or 2n+4, even when the rotor 5 rotates, there will be no difference between N-pole and N-pole or S-pole and S-pole in the negative diametric direction. If they are opposed to each other, the N pole and the S pole can be opposed in the diametrical direction perpendicular to the diametrical direction.

Under such an arrangement of magnetic poles, the rotor 5 rotates, and in the -diameter direction e, there are N poles and N poles, or S poles and S poles.
If the north and south poles are opposite in the diametrical direction f perpendicular to the diametrical direction e, the flexible external gear 2 is an ellipse with the long axis in the e direction and the short axis in the f direction. As a result, the flexible external gear 2 itself does not rotate, but only the oval shape rotates.

In this case, the rotation direction of the ellipse is the same direction as the rotor 5 when the number of magnets in the flexible external gear 2 is 2n-4,
When the number of magnets in the flexible external gear 2 is 2n+4, the direction is opposite to that of the rotor 5.

In this way, as the rotor rotates, the visible external gear can maintain its elliptical shape and rotate only the elliptical shape due to the repulsion and attraction forces of the permanent magnets.

In this case, the number of rotations T of the elliptical shape per rotation of the rotor
is n, and by choosing a large integer for n, it is possible to obtain a small reduction ratio that cannot be obtained with a wave generator.

The above is a case where the visible gear is an external gear, the circular gear is an internal gear, and the rotor is arranged inside the flexible gear. Example 1 and Example 2 described below take this case as an example, but the configuration of the present invention is not limited to this case, and the following three configurations of the present invention are also included in addition to this case. .

(1) When the visible gear is an external gear, the circular gear is an internal gear, and the rotor is placed outside the flexible gear.

(2) When the flexible gear is an internal gear, the circular gear is an external gear, and the rotor is arranged inside the flexible gear.

(3) When the flexible gear is an internal gear, the circular gear is an external gear, and the rotor is placed outside the flexible gear. Example 3, which will be described later, takes this case as an example.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

As described above, there are two types of harmonic gear devices: cup-shaped and flat-type. For convenience of explanation, the embodiment will be described with reference to the cup-shaped one. Needless to say, it can also be applied to flat types.

(Example 1) Example 1 shown in FIGS. 3(a) to (e) has four poles on the rotor,
This is a flexible external gear in which 8 pole permanent magnet pieces are arranged (n=2, corresponding to the case where the code is 10).

In Fig. 3(a), magnets with the same polarity in the a direction and different polarities in the b direction face each other, so the flexible external gear 2 has an elliptical shape with the long axis in the a direction and the short axis in the b direction. Shows a deformed state. As shown in FIG. 3(b), when the rotor rotates 45 degrees, the magnets with different polarities in the a direction and the same polarity in the b direction face each other, so the flexible external gear 2 has a short axis in the a direction, It is deformed into an ellipse with the long axis in the b direction. Below, when the rotor rotates 180 degrees, 270 degrees, and 360 degrees, Figure 3 (c), (d),
The elliptical shape is rotated as shown in (e).

In this embodiment, the number of rotations of the elliptical shape per rotation of the rotor is 2.

The direction of rotation of the elliptical shape is opposite to that of the rotor.

(Example 2) In Example 2 shown in FIGS. 4(a) and (b), the rotor has 8
Four pole permanent magnet pieces are arranged on a pole and a flexible external gear (corresponds to the case where n=4 and the sign is -).

This is an example in which the numbers of magnets in the rotor and flexible external gear are replaced with those in the first embodiment.

In this embodiment, the number of rotations of the elliptical shape per one rotation of the rotor is 4.

The rotation direction of the elliptical shape is the same direction as the rotor.

(Embodiment 3) In Embodiment 3 shown in FIGS. 5(a) and 5(b), the rotor has four
Eight pole permanent magnet pieces are arranged on a flexible external gear (n=2, corresponding to the case where the code is 10).

In this embodiment, as mentioned earlier, the flexible gear is an internal gear,
This example takes the case where the circular gear is an external gear and the rotor is disposed outside the flexible gear, and the principle of operation is the same as in the previous two examples.

In this embodiment, the number of rotations of the elliptical shape per rotation of the rotor is 2.

The direction of rotation of the elliptical shape is opposite to that of the rotor.

〔Effect of the invention〕

According to the present invention, the use of permanent magnets eliminates the need for visible ball bearings conventionally used in wave generators, eliminates the problem of decreased response characteristics due to increased inertial mass, and reduces the overall cost of the device. becomes possible.

In addition, since a wave generator is no longer required and the flexible gear can be bent into an oval shape without contact, there is no need to consider the wear and oil slippage of wave bearings, which have been problems in the past. Life efficiency is improved and problems such as limitations on input shaft rotational speed are also resolved.

Furthermore, as mentioned above, it is possible to obtain a small reduction ratio that cannot be obtained with a wave generator depending on the number of magnets in the rotor and flexible gears, so it is more applicable to the device than when gears are used. will improve. In addition, flexible gears and circular gears can be selected as either external or internal gears.
The fact that the rotor can be placed either inside or outside the flexible gear also contributes to improved applicability to devices.

[Brief explanation of the drawing]

FIG. 1 is a front view of the harmonic gear device according to the present invention, FIG. 2 is a longitudinal sectional view of the harmonic gear device of FIG. 1, and FIGS.
e) is a front view of the first embodiment, FIGS. 4(a) to 4(b) are front views of the second embodiment, and FIGS. 5(a) to (b) are front views of the third embodiment. [Explanation of symbols] 1... Circular gear 2... Flexible gear 3... Permanent magnet piece (first permanent magnet group) 4...
Permanent magnet piece (second permanent magnet group) 5... Rotor Fig. 1 1a Fig. 2 Fig. 4 (a) (b) Fig. 5 (a) (b)

Claims (4)

[Claims] (1) A rigid circular gear and a flexible ring-shaped gear capable of meshing with the circular gear are provided, and the flexible gear is deformed into a substantially elliptical shape to partially mesh with the circular gear. In the harmonic gear device, the harmonic gear device generates relative rotation between the circular gear and the flexible gear according to the difference in the number of teeth by moving the meshing position of both gears along the circumferential direction. A rotor is disposed inside the flexible gear, and around the inside of the flexible gear, a first group of permanent magnets are arranged continuously at approximately equal intervals so that N poles and S poles alternate. attached to the outer periphery of the rotor,
The second permanent magnet group is continuously attached at approximately equal intervals so that north poles and south poles alternate, and on one axis on the orthogonal axis passing through the rotation center of the rotor, Permanent magnets are arranged such that magnets of the same polarity in the first and second permanent magnet groups face each other, and magnets of different polarities in the first and second permanent magnet groups face each other on the other perpendicular axis. A harmonic gear device characterized by an arrangement of. (2) The number of permanent magnet pieces included in the first permanent magnet group is 2n±4 (n is a positive integer of 2 or more), and the number of permanent magnet pieces included in the second permanent magnet group The harmonic gear device according to claim 1, wherein is 2n. (3) A rigid circular gear and a flexible ring-shaped gear that can mesh with the circular gear, and the flexible gear is deformed into a substantially elliptical shape to partially mesh with the circular gear. In the harmonic gear device, the harmonic gear device generates relative rotation between the circular gear and the flexible gear according to the difference in the number of teeth by moving the meshing position of both gears along the circumferential direction. A rotor is arranged on the outside of the flexible gear, and around the outside of the flexible gear, a first group of permanent magnets are arranged continuously at approximately equal intervals so that N poles and S poles alternate. attached to the inner periphery of the rotor,
The second permanent magnet group is continuously attached at approximately equal intervals so that north poles and south poles alternate, and on one axis on the orthogonal axis passing through the rotation center of the rotor, Permanent magnets are arranged such that magnets of the same polarity in the first and second permanent magnet groups face each other, and magnets of different polarities in the first and second permanent magnet groups face each other on the other perpendicular axis. A harmonic gear device characterized by an arrangement of. (4) The number of permanent magnet pieces included in the first permanent magnet group is 2n±4 (n is a positive integer of 2 or more), and the number of permanent magnet pieces included in the second permanent magnet group The harmonic gear device according to claim 3, wherein is 2n.