# US 11,906,026 B2 · Frictional wave reducer

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- Number: US 11,906,026 B2
- Document ID: US11906026B2
- Status: Granted
- Kind: B2
- Application number: 17/417,716
- Filed: 2021-03-05
- Published: 2023-08-17
- Granted: 2024-02-20
- Earliest claimed: 2020-03-06
- Assignees: C&M Robotics Co., Ltd.
- Applicants: C and M Robotics Co., Ltd.
- Inventors: Sang Wan Joo
- Web page: https://patentgrep.com/patent/US11906026B2

## CPC

- F16C 19/10: for axial load mainly
- F16H 49/001: {Wave gearings, e.g. harmonic drive transmissions}
- B25J 9/1025: {Harmonic drives (in general: F16H49/001)}
- B25J 17/00: Joints
- F16C 17/04: for axial load only
- F16C 2322/59: Manipulators, e.g. robot arms
- F16C 2361/61: Toothed gear systems, e.g. support of pinion shafts
- F16H 2049/003: {Features of the flexsplines therefor}
- F16C: SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
- F16H: GEARING
- B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50})

## Abstract

The present disclosure relates to a frictional wave reducer mainly used for industrial robot joints and having an operating principle modified from that of a conventional strain wave gearing, which includes a wave generator having a conic pressurizing face on the outermost side, a toothless flex spline having a conic friction tube in which the wave generator is accommodated with the conic pressurizing face inscribed in the conic friction tube, and a toothless circular spline accommodating the toothless flex spline and having an internal conic friction face in which the conic friction tube is inscribed at a plurality of axially symmetrical points to form an internal friction wheel with the toothless flex spline. Accordingly, disadvantages of the conventional strain wave gearing are overcome to provide a reducer having high productivity and high rotation accuracy without generation of vibration and noise.

## Claims

### Claim 1

A frictional wave reducer comprising:
a wave generator having a conic pressurizing face on the outermost side;
a toothless flex spline having a conic friction tube in which the wave generator is accommodated with the conic pressurizing face inscribed in the conic friction tube;
a toothless circular spline accommodating the toothless flex spline and having an internal conic friction face in which the conic friction tube is inscribed at a plurality of axially symmetrical points to form an internal friction wheel with the toothless flex spline;
a pressurizing means for generating frictional force between the conic friction tube and the internal conic friction face by pressurizing the wave generator in an axial direction,
wherein the pressurizing means includes a plug which pressurizes the wave generator by means of a thrust bearing; and
an intermediate plate for motor mounting which is combined with one end of the circular spline in the axial direction and accommodates the plug,
wherein an outer circumferential face of the plug and an inner circumferential face of the intermediate plate are combined with each other through screw joining such that pressurizing force applied by the plug to the wave generator is controllable.

### Claim 2 (depends on 1)

The frictional wave reducer of claim 1, wherein the plug includes a rim having an outer circumferential face combined with the inner circumferential face of the intermediate plate through screw joining, an elastic flange inwardly extending from an inner circumferential face of the rim, and a hub formed at an inner edge of the elastic flange and pressurizing the thrust bearing through one edge in the axial direction, and the elastic flange is elastically deformed in an opposite axial direction in proportion to the pressurizing force through the hub.

### Claim 3 (depends on 1)

The frictional wave reducer of claim 1, wherein the plug pressurizes the thrust bearing by means of a spring, and the spring is elastically compressively deformed in the axial direction in proportion to the pressurizing force.

### Claim 4

A frictional wave reducer comprising:
a wave generator having a conic pressurizing face on the outermost side;
a toothless flex spline having a conic friction tube in which the wave generator is accommodated with the conic pressurizing face inscribed in the conic friction tube;
a toothless circular spline accommodating the toothless flex spline and having an internal conic friction face in which the conic friction tube is inscribed at a plurality of axially symmetrical points to form an internal friction wheel with the toothless flex spline;
a pulling means for pulling the wave generator in the axial direction to generate frictional force between the conic friction tube and the internal conic friction face,
wherein the pulling means includes an extension shaft extending from the wave generator in the axial direction and passing through the center of the flex spline, a bearing rotatably supporting the extension shaft with respect to the flex spline, and a plug combined with the extension shaft to come into contact with the bearing to be supported in the axial direction;
wherein an inner circumferential face of the plug and an outer circumferential face of the extension shaft are combined with each other through screw joining such that tension applied by the plug to the wave generator is controllable; and
wherein the plug includes a hub having an inner circumferential face combined with the outer circumferential face of the extension shaft through screw joining, an elastic flange outwardly extending from an outer circumferential face of the hub, and a rim formed at an outer edge of the elastic flange and supported by the bearing through one edge in the axial direction, and the elastic flange is elastically deformed in an opposite axial direction in proportion to the tension through the hub.

### Claim 5

A frictional wave reducer comprising:
a wave generator having a conic pressurizing face on the outermost side;
a toothless flex spline having a conic friction tube in which the wave generator is accommodated with the conic pressurizing face inscribed in the conic friction tube;
a toothless circular spline accommodating the toothless flex spline and having an internal conic friction face in which the conic friction tube is inscribed at a plurality of axially symmetrical points to form an internal friction wheel with the toothless flex spline;
a pulling means for pulling the wave generator in the axial direction to generate frictional force between the conic friction tube and the internal conic friction face,
wherein the pulling means includes an extension shaft extending from the wave generator in the axial direction and passing through the center of the flex spline, a bearing rotatably supporting the extension shaft with respect to the flex spline, and a plug combined with the extension shaft to come into contact with the bearing to be supported in the axial direction;
wherein an inner circumferential face of the plug and an outer circumferential face of the extension shaft are combined with each other through screw joining such that tension applied by the plug to the wave generator is controllable; and
wherein the plug is supported by the bearing by means of a spring, and the spring is elastically compressively deformed in proportion to the tension.