JP2673004B2 - Wave gear device - Google Patents

Description

The present invention relates to a wave gear device, and more particularly to a wave gear device including a wave generator using a magnetic fluid.

[Conventional technology]

As a wave generator of a conventional wave gear device, a wave generator including an elliptical plate and a flexible bearing fitted around the outside of the plate is often used.

[Problems to be solved by the invention]

However, in this wave generator, there are many sliding parts such as an elliptical plate and a flexible bearing, and a flexible bearing and a flexspline, and fretting corrosion (fine movement wear).
Was associated with the problem. Various lubrication methods have been proposed to solve this problem, but even if these methods are used, a mechanism for lubrication must be newly provided, which complicates the structure of the wave gear device. .

The present invention has been made in view of this point, and an object thereof is to provide a wave gear device that eliminates the problem of wear by eliminating the sliding portion of the wave generator and that does not require lubrication as a measure against wear. To do.

[Means for solving the problem]

In order to achieve this object, the wave generator of the wave gear device according to the present invention is characterized by comprising a means for generating a rotating magnetic field and a magnetic fluid sealed so as to be movable around the rotating magnetic field. .

(Operation)

According to the above configuration of the present invention, when a magnetic field is generated, the magnetic fluid is attracted to the periphery of the magnetic field, and the flexspline is transformed into a non-circular shape (often an elliptical shape). Then, when the magnetic field is rotated, the magnetic fluid also moves with the rotation of the magnetic field, so that the flexspline can be partially meshed with the circular spline without generating a sliding portion.

〔Example〕

1 and 2 show an embodiment of a wave gear device according to the present invention. FIG. 1 is a sectional view taken along a plane passing through the axis of the flexspline, and FIG. 2 is XX of FIG.
It is sectional drawing in a line.

The wave gear device 1 includes a circular spline 2, a flexspline 3, and a wave generator 4 that bends the flexspline 3 into an elliptical shape and meshes with the circular spline 2 at two positions. The flexspline 3 is connected to the output shaft 5 at its closed end. The wave generator 4 includes a rotating magnetic field generating means 6 and a magnetic fluid 7 that can move around the rotating magnetic field generating means 6. The rotating magnetic field generating means 6 has twelve electromagnets 9 arranged radially inside the disk-shaped member 8 at substantially equal intervals around the axis of the flexspline 3. The magnetic fluid 7 is hermetically sealed by the disk-shaped member 8 and the sealing material 10, and can move around the disk-shaped member 8 along the circumference of the disk-shaped member 8.

 The wave gear device 1 operates as follows.

First, among the electromagnets 9 incorporated in the disk-shaped member 8, only one set of electromagnets facing each other in the diameter direction of the disk-shaped member 8, for example, the electromagnets 9a and 9b shown in FIG. 2 are magnetized. As a result, the magnetic fluid 7 is attracted only around the electromagnets 9a and 9b, and the flexspline 3 is deformed into an elliptical shape whose major axis is the diameter connecting the electromagnets 9a and 9b.

Next, a pair of electromagnets 9 facing each other in the diametrical direction of the disk-shaped member 8 are continuously magnetized, for example, clockwise to form a rotating magnetic field. As the magnetic field moves clockwise, the magnetic fluid also moves along with the magnetic field along the circumference of the disk-shaped member 8. For this reason, the ellipse formed by the flexspline 3 is rotated clockwise, the meshing position between the circular spline 2 and the flexspline 3 moves, and the circular spline 3 and the flexspline 2 are moved to each other. Causes relative rotation. This movement can be taken out as an output from the output shaft 5.

The scope of the present invention is not limited to the above examples, and various modifications are possible within the scope of the invention described in the claims, and those are also included in the scope of the present invention. Is.

For example, in the above-described embodiment, the wave gear device in which the circular spline 2 is the internal gear and the flexspline 3 is the external gear has been given as an example. It is also applicable to a wave gear device in the form of an internal gear.

Further, the rotating magnetic field is formed by arranging electromagnets in a circular shape and sequentially magnetizing as in the embodiment,
For example, it can be formed by rotating a permanent magnet.

When the rotating magnetic field is formed by using electromagnets, the number of electromagnets is arbitrary, but it is most preferably a multiple of 4.

〔The invention's effect〕

According to the present invention, the sliding portion in the wave generator of the wave gear device can be eliminated. Along with this, the problem of wear disappears, and it becomes unnecessary to perform lubrication as a measure against wear.

[Brief description of the drawings]

FIG. 1 is a sectional view of a wave gear device according to the present invention, and FIG. 2 is a sectional view taken along line XX of FIG. [Description of Reference Signs] 1 ... Wave gear device, 2 ... Circular spline 3 ... Flexspline, 4 ... Wave generator 5 ... Output shaft, 6 ... Rotating magnetic field generating means 7 ... Magnetic fluid, 8 ... … Disc-shaped member 9 …… Electromagnet, 10 …… Sealing material.

Claims (1)

(57) [Claims] 1. A wave gear device comprising a circular spline, a flexspline, and a wave generator which flexes the flexspline in a non-circular shape and partially meshes with the circular spline, wherein the wave generator is a rotating magnetic field generating means. And a magnetic fluid device which is composed of a magnetic fluid sealed so as to be movable around the rotating magnetic field generating means.