Coaxial gear mechanism with positive transmission ratio
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 ).
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 .