Coaxial gear mechanism with positive transmission ratio

Patent metadata

Field	Value
Publication number	US-10830328-B2
Application number	US-201815880814-A
Country	US
Kind code	B2
Filing date	Jan 26, 2018
Priority date	Jan 26, 2017
Publication date	Nov 10, 2020
Grant date	Nov 10, 2020

Abstract

Gear mechanism ( 1 ), in particular coaxial gear mechanism, having an internal gear ( 3 ) with an inwardly directed toothing ( 5 ), a tooth carrier ( 11 ) which is arranged coaxially with respect to the internal gear and in which a multiplicity of teeth ( 7 ) for engaging with the toothing ( 5 ) are accommodated, wherein the teeth ( 7 ) are mounted radially displaceably in the tooth carrier ( 11 ), a drive element with a profiling ( 22 ) for radially driving the radially displaceably mounted teeth ( 7 ), wherein the profiling ( 22 ) has, over its circumference, at least two elevations, wherein the gear mechanism is constructed such that there is a positive transmission ratio between a drive via the drive element and an output via the tooth carrier ( 11 ).

First claim

The invention claimed is:

1. Coaxial gear mechanism ( 1 , 201 ), comprising
an internal gear ( 3 ) with an inwardly directed toothing ( 5 ),
a tooth carrier ( 11 ) which is arranged coaxially with respect to the internal gear and in which a multiplicity of teeth ( 7 ) for engaging with the toothing ( 5 ) are accommodated, wherein the teeth ( 7 ) are mounted radially displaceably in the tooth carrier ( 11 ),
a drive element ( 20 ) with a profiling ( 22 ) for radially driving the radially displaceably mounted teeth ( 7 ), wherein the profiling ( 22 ) has, over its circumference, at least two elevations,
wherein the gear mechanism is constructed such that there is a positive transmission ratio between a drive via the drive element ( 20 ) and an output via the tooth carrier ( 11 ),
rolling bodies ( 23 ) which are arranged on the profiling ( 22 ), and
a multiplicity of pivot segments ( 24 ) for the mounting of the teeth ( 7 ), wherein the pivot segments ( 24 ) are arranged on the rolling bodies ( 23 ),
wherein the tooth carrier tooth pitch angle of the teeth ( 7 ) is smaller than the internal gear tooth pitch angle of the internal teeth of the toothing ( 5 ) of the internal gear ( 3 ), and

wherein the number of teeth ( 7 ) is calculated in accordance with the following formula:

Z
z

=

Z
I

+
E

PF

,

wherein Zz is the number of teeth ( 7 ) in the tooth carrier ( 11 ), wherein ZI is the number of internal teeth of the internal gear ( 3 ), and wherein E is a number of elevations of the profiling ( 22 ) of the drive element, and wherein PF is a position factor which is an integer, and wherein E is at least two.

2. Gear mechanism ( 1 ) according to claim 1 , wherein, in the tooth carrier ( 11 ), only every at least second position predefined by the tooth carrier tooth pitch angle is occupied by a tooth ( 7 ).

3. Gear mechanism ( 1 ) according to claim 1 , wherein the number of teeth ( 7 ) is greater, by at least or exactly one, than half of the number of internal teeth of the toothing ( 5 ) of the internal gear ( 3 ).

4. Gear mechanism ( 1 ) according to claim 1 , wherein the rolling bodies ( 23 ) are arranged in at least two rolling body rows, which are parallel in the direction of rotation of the cam disk, on the profiling ( 22 ).

5. Gear mechanism ( 1 ) according to claim 1 , wherein the profiling ( 22 ) has at least two parallel running surfaces which are divided by an at least partially encircling central rib ( 34 ).

6. Gear mechanism ( 1 ) according to claim 1 , wherein each of the teeth ( 7 ) is formed as a single piece.

7. Gear mechanism ( 1 ) according to claim 1 , wherein the forces for the guidance of the teeth ( 7 ) in the tooth carrier ( 11 ) are reduced by at least 10% as compared to a gearing having a negative transmission ratio.

8. Gear mechanism ( 1 ) according to claim 1 , wherein the internal teeth of the toothing ( 5 ) and the teeth ( 7 ) each have tooth tips which, in cross section, correspond to a truncated pyramid or a pyramid in each case with curved flanks.

9. Gear mechanism ( 1 ) according to claim 1 , wherein the internal teeth of the toothing ( 5 ) and the teeth ( 7 ) each have a radius on the tip of the tooth.

10. Method for producing a gear mechanism ( 1 ) according to claim 1 .

Assignees

• Wittenstein Se

Inventors

• Schreiber Heiko

Classifications

• F16H55/16

  relating to teeth only · CPC title

• F16H49/00 Primary

  Other gearings · CPC title

• F16H25/06 Primary

  with intermediate members guided along tracks on both rotary members · CPC title

• F16H55/08

  Profiling · CPC title

• F16H49/001 Primary

  Wave gearings, e.g. harmonic drive transmissions · CPC title