Planetary gear mechanism for a bicycle
View Patent ↗A planetary gear mechanism for a bicycle, and more particularly to a planetary gear mechanism comprising a first planetary mechanism connected coaxially in series to a second planetary mechanism, which second planetary mechanism is connected coaxially in series to a third planetary mechanism, the second planetary mechanism output is a step up in speed from the first planetary mechanism output, the third planetary mechanism output is a step up in speed from the second planetary mechanism output.
1. A planetary gear mechanism comprising:
an input member ( 22 );
a first carrier ( 100 ) having a first carrier first pinion gear (P 1 ) and a first carrier second pinion gear (P 2 ), each journalled to the first carrier, the first carrier rotationally fixed to the input member ( 22 ), the first carrier second pinion gear (P 2 ) engaged with a first brake (Brake 1 ) through a sun gear (S 1 );
a second carrier ( 200 ) having second carrier first pinion gear (P 4 ) and a second carrier second pinion gear (P 5 ), each pinion gear (P 4 ), (P 5 ) is journalled to the second carrier, the second carrier engaged with a second brake (Brake 2 );
a first ring gear (R 1 ) in meshing engagement with the first carrier first pinion gear (P 1 ), a second ring gear (R 2 ) in meshing engagement with the second carrier first pinion gear (P 4 ), the first ring gear and second ring gear comprise a ring gear member ( 400 );
a third carrier ( 300 ) having a third carrier first pinion gear (P 6 ) and a third carrier second pinion gear (P 7 ), each pinion gear (P 6 ), (P 7 ) is journalled to the third carrier;
a third ring gear (R 3 ) in meshing engagement with the second carrier second pinion gear (P 5 ), the third ring gear fixedly connected to the third carrier ( 300 );
a fourth ring gear (R 4 ) engaged with a third brake (Brake 3 ) and in meshing engagement with the third carrier first pinion gear (P 6 );
a first one-way clutch (CL 1 ) engaged between the first carrier ( 100 ) and the ring gear member ( 400 );
a second one-way clutch (CL 2 ) engaged between the second carrier ( 200 ) and the ring gear member ( 400 );
a third one-way clutch (CL 3 ) engaged between the third carrier ( 300 ) and the fourth ring gear (R 4 ); and
an output member ( 44 ) in meshing engagement with the third carrier second pinion gear (P 7 ).
2. The planetary gear mechanism as in claim 1 further comprising:
a first carrier third pinion gear (P 3 ); and
a sun gear (S 2 ) in meshing engagement with a first carrier third pinion gear (P 3 ); and
a fourth brake (Brake 4 ) engaged with the sun gear (S 2 ).
3. The planetary gear mechanism as in claim 1 , wherein the planetary gear mechanism is integrated into a bicycle frame.
4. The planetary gear mechanism as in claim 1 , wherein the first carrier is connected coaxially in series to the second carrier, which second carrier is connected coaxially in series to the third carrier.
5. The planetary gear mechanism as in claim 1 , wherein the first brake comprises a pivoting shift member for releasably engaging a tooth on the sun gear (S 1 ).
6. The planetary gear mechanism as in claim 1 , wherein the second brake comprises a pivoting shift member for releasably engaging a tooth on the second carrier.
7. The planetary gear mechanism as in claim 1 , wherein the third brake comprises a pivoting shift member for releasably engaging a tooth on the ring gear (R 4 ).
8. The planetary gear mechanism as in claim 2 , wherein the fourth brake comprises a pivoting shift member for releasably engaging a tooth on the sun gear (S 2 ).
9. A transmission comprising:
an input member;
a first planetary mechanism;
a second planetary mechanism;
a third planetary mechanism;
the first planetary mechanism which is serially coupled to the second planetary mechanism which is serially coupled to the third planetary mechanism;
a shift mechanism comprising a first rotatable circumferential surface, a first shift dog having a shift position determined by engagement with the rotatable circumferential surface, the first shift dog releasably engaging a first planetary mechanism sun gear;
the first shift dog cooperatively engaged with a second shift dog, the second shift dog having a shift position determined by engagement with a second rotatable circumferential surface, the second shift dog releasably engaged with a second planetary mechanism sun gear;
the first shift dog and the second shift dog not being simultaneously engagable with the first planetary mechanism sun gear and the second planetary mechanism sun gear;
a first one-way clutch engaged between a first carrier and a ring gear member;
a second one-way clutch engaged between a second carrier and the ring gear member;
a third one-way clutch engaged between a third carrier and a fourth ring gear; and
an output member in meshing engagement with a third carrier second pinion gear, the output member comprising a sprocket, the sprocket having a plurality of holes, each hole being engagable by a belt tooth.
10. The transmission as in claim 9 , wherein the first rotatable circumferential surface is disposed radially outward of the first planetary mechanism.
11. The transmission as in claim 9 , wherein the first rotatable circumferential surface and the second rotatable circumferential surface are each disposed radially inward on a shift cam ring.
12. The transmission as in claim 9 , wherein a resilient member is operably disposed between the first shift dog and the first rotatable circumferential surface.
13. The transmission as in claim 9 , wherein:
the input member is connected to the first planetary mechanism;
the second planetary mechanism rotary output is a step up in speed from the first planetary mechanism rotary output, the third planetary mechanism rotary output is a step up in speed from the second planetary mechanism rotary output; and
the third planetary mechanism is connected to the output member.