CA1065163A - Epicyclic cog belt speed reducer - Google Patents
Epicyclic cog belt speed reducerInfo
- Publication number
- CA1065163A CA1065163A CA286,284A CA286284A CA1065163A CA 1065163 A CA1065163 A CA 1065163A CA 286284 A CA286284 A CA 286284A CA 1065163 A CA1065163 A CA 1065163A
- Authority
- CA
- Canada
- Prior art keywords
- planet
- sun
- shaft
- planetary
- input
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H7/00—Gearings for conveying rotary motion by endless flexible members
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transmission Devices (AREA)
- Retarders (AREA)
Abstract
ABSTRACT
In mechanical apparatus for reducing angular speed, commonly known as speed reducers, its is known as a planetary type reducer with a very high reduction ratio; in the order of 1000:1 and high-er, It has concentric input and output shafts, on each of which is fixed a sun cogwheel; there is a third sun cogwheel, also on the main axis, which is fixed to the frame. Each sun cogwheel is connected to a planet cogwheel with a cog belt to form a planetary set, The three planet cogwheels are fast on a common shaft which rotates about its own axis and also about the axis of the input and output shafts; as the planets spin, they are drawn about their respective suns and the teeth on the planet wheels describe an epicyclic path, The speed reduction ratio is dependent mainly on the difference in the relative sizes of the output sun wheel and the sun wheel fixed to the main frame; when there is zero differ-ence the reduction ratio is infinite, Chains and sprocket wheels can be used in place of cog belts and cogwheels in applications where maximum output torque is required.
In mechanical apparatus for reducing angular speed, commonly known as speed reducers, its is known as a planetary type reducer with a very high reduction ratio; in the order of 1000:1 and high-er, It has concentric input and output shafts, on each of which is fixed a sun cogwheel; there is a third sun cogwheel, also on the main axis, which is fixed to the frame. Each sun cogwheel is connected to a planet cogwheel with a cog belt to form a planetary set, The three planet cogwheels are fast on a common shaft which rotates about its own axis and also about the axis of the input and output shafts; as the planets spin, they are drawn about their respective suns and the teeth on the planet wheels describe an epicyclic path, The speed reduction ratio is dependent mainly on the difference in the relative sizes of the output sun wheel and the sun wheel fixed to the main frame; when there is zero differ-ence the reduction ratio is infinite, Chains and sprocket wheels can be used in place of cog belts and cogwheels in applications where maximum output torque is required.
Description
~o65~3 This invention relates to a mechanical apparatus for modify-ing angular speed or torque, commonly Xnown as ~peed reducerss and when combined with a motor, commonly known ~s gearmotorss and where a gearmotor is built into a drum for purposes of rotat-ing the dru~, commonly known as a drummotor in conveyor applicat-~onss and when combined with other equipment to affect a large change in velocity or torque, to operate ~alves or po~ition equip-ment such as doors, etc., commonlyknown as actuators.
It is common in applications where a speed reducer with a large velocity ratio is required, to use an apparatus consisting of a worm screw and a worm gear, commonly known as a worm gear re-du~er, rather than a n~mber of gears in series, as in a gear train, as is common with reducers for low ratio applications, because the worm gear reducer generally requires fewer parts, particularily with ratios higher than 30-40 to one, Furthermore, it i8 common to use several worm gear reducers in series combination for high reduction ratios, of several hundred and even several thousand to one~ however, the overall efficiency decreases as stages are add-20 ed, and con~iderable heating and 108s of efficiency results from sliding friction between the worm screw and the worm gear, partic-ularil~ at input speeds of 2000 revolutions per minute, and high-er. Generally, high ratio worm gear reducers are known to have transmission losses as high as 80-90 percsnt.
~ ore recently a number of differential type reducers have been deYeloped for high reduction ratio applications, which have lower losses than the worm gear reducers~ of these the cam type reducer is better suited to the very high reduction ratio applic-ations, particularily for ratios of several thousand to one and 30 higher. This reducer is described generally as follows~ it has two gear-like cams, each slightly smaller than a disc or annulus gear to which ea~h cam is mated: one disc is fixed and serves as a reaction gear, while the other disc rotates and could be consid-10~5163 1 ered as the output gear; the cams are joined together and are driven about the inside of the annuluses by an eccentric mounted on the input shaft~ the output gear rotates due to the cams ha~-ing different number of lobes. The cam type gear reducer has had limited acceptance 80 far, because complex technology is required to produ~e the high precision cams necessary to minimize noise and wear due to sliding and rolling friction between parts either the use of molded plastic, cast metal, or powder metallurgy tech-niques - with concomitant high production costs. Furthermore, 10 this reducer is not well suited for very high input speeds.
The gear type differential planetary reducer i8 suitable for reduction ratios in the order of one thousand to one with a conc-entric input and output shaft arrangementt and i8 well suited to high output torque applicationss however, input æpeed must be lim-ited to 1800 revolutions or les~, to avoid heating and lubricating problems, Furthermore, these reducers are generally of heavy weig-ht.
It is an ob~e¢t of this invention to provide an improved device with a reduction ratio in the range of 1000-lO,OOOtl~ part-20 icularily, w~th much higher transmission efficiency in that rangethan the worm gear reducer~ with similar high efficency as the cam type differential æpeed reducer, but without the use of complex cams, or annular gears, or disc-gears, and thereby avoiding any requirement for exotic manufacturing téchniques; with quieter.oper-ation at input speeds of 3000 re~olution~ per minute and higher~
and for use with smaller, higher speed motors to provide a lighter gearmotor for a particular speed-torque requirement.
.. It is a further object to pro~ide concentrio input and output : shafts with a plurality o~ enclosuress a separate enclosure with 30 its own mounting feet; or integral with a motor in a gearmotor ; type enclosure~ or with its own mounting feet and a bracket on theinput endplate for a standard frame motor~ or with its own mount-ing feet and a flange on the input endplate for a flange type . -3-~065163 1 motor.
Another object of the invention is to provide large varia-tions in speed reduction ratios wîthin the same speed reducer ~rame size, simply by changing cogwheels and cog belts.
Anbther object i8 to pro~ide a dry, permanently lubricated ~peed reducer.
Other ob~ects and a fuller understanding of the invention may be had by referring to the following description and claims ta~en in conjunction with the accompanying drawings in which Figure 1 is an elevation of the output end of one embodiment, Figure 2 is a section of the line I-I of Figure 1, Figure 3 i~ another embodiment of the input endplate 12 shown in Figure,2, Figure 4 is another embodiment of the input endplate 12 ~hown jn Figure 2, Figure 5 is another embodiment Or the carrier assembly 11 ~hown in ~igure 2, The reaucer illustrated comprises an input shaft 1 which is free to rotate in one end of the output shaft 2; the two ~hafts 20 are concentric and foxm the main axis of the reducer. The sun cog-wheel 3 of the input planetary set, cogwheel~ 3&5, Ss ~ixed on the input shaft 1, and coupled with a cog belt 4a to the planet cog-wheel 5. Cogwheel 5 is fixed on the moving shaft 6, and rotates on its own axis and also about the ma;~ a~is o~ the reducer in an epicyclic motlon. Planet cogwheels 7&8 are fixed on either end of the rotating shaft 6; planet cogwheel 7 is part of the reaction planetary set, cogwheels 7&9; planet cogwheel 8 is part of the out-put p~anetary set, co~heels 8~10. These planet cogwheels are coupled with c~g bel~s ~b&4c to the respective ~un cogwheels of 30 the reaction and the output planetaries. A carrier assembl~ 11, ~o~nted freely on the input shaft 1, serves aD a moving arm t~
support the planets and the moving shaft 6. Sun co~wheel 9 is fix-ed to the input endplate 12 by screws 13. Sun cogwheel 10 is fix-~)65~3 1 ed on the output shaft 2 The output endplate 14, and the input endplate 12, and the mounting frame 15 are held together with thr-ough-bolts 16. Bearings 17 are mounted at points of rotation in t]he carrier assembly 11, in the endplates 12&13, and in one end of the output shaft 2. A spacer tube 18 fixed on the input shaft 1 maintains the carrier assembly 11 in position as it rotates on the-main axis. When shaft 1 is rotated, shaft 6 rotates and moves ar-ound the main axis of the reducer, being dra-~n ~round the fixed sun wheel 9 as the planet wheel 7 operates on the inside of the 10 cog belt 4b. The output planetary set, cog~heels 8~10, operates similar to the reaction set, cogPfheels 7&9; ~hen the cog~fheels in the reaction set haYe a gear ratio equal to that of the cogwheels in the out~ut set, the ~ut~ut shaft 2 speed is zero, independent of ~ny s~eed or change ln speed of input shaft 1 and the reduction ratl~ is infinite. A slight difference in the ratios betweer. the react;on set 7~9 and ~he out~ut set 8&10 permits a hi~h overall reduction ratio, between ~he in~ut and the output snafts, some-tning less than in~inity; the closer the matching ~f these ratios, tne higher the overall reduction ratio. The reduc~i3n ratio var-20 ies over a wide ran~e fo~ s~all changes in the numcer ol cogs oneither of the l~rEe cogwheels 9~10. ~hen ratio of th~ output set 8~10 is higher than the ratio of the reaction set 7~9, the output sh~ft 2 rotates in the o~site direction to the input shaft 1;
when it is lower, it turrs in the samé direction.
Alternative end~lates are sho~rn in Figures 3 and 4 for the input endplate 12; end~l2ve 19 is suitable for receiving a stand-ard frame ~otor; endplate 20 is suitable for a flan~e frame motor.
Another embodimen~ of the carrier assembly 11, Ln~ as a du~lex carrier assembly, is sho~n in Figure 5; a seco;~d shaft 6 30 ~-~ associated co~lheels has beer added to balance the arm and to ~ro-~ide 2 stronger tie ~e~ween t:ne reaction co~wheel 9 and ~he ou~ut cogwheel 10; a ~i~er cog~heel 21 is used on the input shaft 1 and lon~er cog ~elts 22 are used on the reaction set and on the 10651~;3 1 outpu~ set. ~he reaction set cog belt 22 is shown in section in r'i~ure 5, as is t~e reaction co~wheel 9; the driver cogwh~els 8 of the output set ~10 are connected with a co~ belt 22 (not shown) to the output co~wheel 10 (not shown). Similarily, a tri-plex assembly, could be used in place of the simplex and duplex assemblies described above.
Chains could be used in place of cog belts in applications where temperature or stress could reduce the life of cog belts.
It can be shown that the invention has the following reduct-ion ratio:
1 ~ N N
N9~7 118NlO
It is common in applications where a speed reducer with a large velocity ratio is required, to use an apparatus consisting of a worm screw and a worm gear, commonly known as a worm gear re-du~er, rather than a n~mber of gears in series, as in a gear train, as is common with reducers for low ratio applications, because the worm gear reducer generally requires fewer parts, particularily with ratios higher than 30-40 to one, Furthermore, it i8 common to use several worm gear reducers in series combination for high reduction ratios, of several hundred and even several thousand to one~ however, the overall efficiency decreases as stages are add-20 ed, and con~iderable heating and 108s of efficiency results from sliding friction between the worm screw and the worm gear, partic-ularil~ at input speeds of 2000 revolutions per minute, and high-er. Generally, high ratio worm gear reducers are known to have transmission losses as high as 80-90 percsnt.
~ ore recently a number of differential type reducers have been deYeloped for high reduction ratio applications, which have lower losses than the worm gear reducers~ of these the cam type reducer is better suited to the very high reduction ratio applic-ations, particularily for ratios of several thousand to one and 30 higher. This reducer is described generally as follows~ it has two gear-like cams, each slightly smaller than a disc or annulus gear to which ea~h cam is mated: one disc is fixed and serves as a reaction gear, while the other disc rotates and could be consid-10~5163 1 ered as the output gear; the cams are joined together and are driven about the inside of the annuluses by an eccentric mounted on the input shaft~ the output gear rotates due to the cams ha~-ing different number of lobes. The cam type gear reducer has had limited acceptance 80 far, because complex technology is required to produ~e the high precision cams necessary to minimize noise and wear due to sliding and rolling friction between parts either the use of molded plastic, cast metal, or powder metallurgy tech-niques - with concomitant high production costs. Furthermore, 10 this reducer is not well suited for very high input speeds.
The gear type differential planetary reducer i8 suitable for reduction ratios in the order of one thousand to one with a conc-entric input and output shaft arrangementt and i8 well suited to high output torque applicationss however, input æpeed must be lim-ited to 1800 revolutions or les~, to avoid heating and lubricating problems, Furthermore, these reducers are generally of heavy weig-ht.
It is an ob~e¢t of this invention to provide an improved device with a reduction ratio in the range of 1000-lO,OOOtl~ part-20 icularily, w~th much higher transmission efficiency in that rangethan the worm gear reducer~ with similar high efficency as the cam type differential æpeed reducer, but without the use of complex cams, or annular gears, or disc-gears, and thereby avoiding any requirement for exotic manufacturing téchniques; with quieter.oper-ation at input speeds of 3000 re~olution~ per minute and higher~
and for use with smaller, higher speed motors to provide a lighter gearmotor for a particular speed-torque requirement.
.. It is a further object to pro~ide concentrio input and output : shafts with a plurality o~ enclosuress a separate enclosure with 30 its own mounting feet; or integral with a motor in a gearmotor ; type enclosure~ or with its own mounting feet and a bracket on theinput endplate for a standard frame motor~ or with its own mount-ing feet and a flange on the input endplate for a flange type . -3-~065163 1 motor.
Another object of the invention is to provide large varia-tions in speed reduction ratios wîthin the same speed reducer ~rame size, simply by changing cogwheels and cog belts.
Anbther object i8 to pro~ide a dry, permanently lubricated ~peed reducer.
Other ob~ects and a fuller understanding of the invention may be had by referring to the following description and claims ta~en in conjunction with the accompanying drawings in which Figure 1 is an elevation of the output end of one embodiment, Figure 2 is a section of the line I-I of Figure 1, Figure 3 i~ another embodiment of the input endplate 12 shown in Figure,2, Figure 4 is another embodiment of the input endplate 12 ~hown jn Figure 2, Figure 5 is another embodiment Or the carrier assembly 11 ~hown in ~igure 2, The reaucer illustrated comprises an input shaft 1 which is free to rotate in one end of the output shaft 2; the two ~hafts 20 are concentric and foxm the main axis of the reducer. The sun cog-wheel 3 of the input planetary set, cogwheel~ 3&5, Ss ~ixed on the input shaft 1, and coupled with a cog belt 4a to the planet cog-wheel 5. Cogwheel 5 is fixed on the moving shaft 6, and rotates on its own axis and also about the ma;~ a~is o~ the reducer in an epicyclic motlon. Planet cogwheels 7&8 are fixed on either end of the rotating shaft 6; planet cogwheel 7 is part of the reaction planetary set, cogwheels 7&9; planet cogwheel 8 is part of the out-put p~anetary set, co~heels 8~10. These planet cogwheels are coupled with c~g bel~s ~b&4c to the respective ~un cogwheels of 30 the reaction and the output planetaries. A carrier assembl~ 11, ~o~nted freely on the input shaft 1, serves aD a moving arm t~
support the planets and the moving shaft 6. Sun co~wheel 9 is fix-ed to the input endplate 12 by screws 13. Sun cogwheel 10 is fix-~)65~3 1 ed on the output shaft 2 The output endplate 14, and the input endplate 12, and the mounting frame 15 are held together with thr-ough-bolts 16. Bearings 17 are mounted at points of rotation in t]he carrier assembly 11, in the endplates 12&13, and in one end of the output shaft 2. A spacer tube 18 fixed on the input shaft 1 maintains the carrier assembly 11 in position as it rotates on the-main axis. When shaft 1 is rotated, shaft 6 rotates and moves ar-ound the main axis of the reducer, being dra-~n ~round the fixed sun wheel 9 as the planet wheel 7 operates on the inside of the 10 cog belt 4b. The output planetary set, cog~heels 8~10, operates similar to the reaction set, cogPfheels 7&9; ~hen the cog~fheels in the reaction set haYe a gear ratio equal to that of the cogwheels in the out~ut set, the ~ut~ut shaft 2 speed is zero, independent of ~ny s~eed or change ln speed of input shaft 1 and the reduction ratl~ is infinite. A slight difference in the ratios betweer. the react;on set 7~9 and ~he out~ut set 8&10 permits a hi~h overall reduction ratio, between ~he in~ut and the output snafts, some-tning less than in~inity; the closer the matching ~f these ratios, tne higher the overall reduction ratio. The reduc~i3n ratio var-20 ies over a wide ran~e fo~ s~all changes in the numcer ol cogs oneither of the l~rEe cogwheels 9~10. ~hen ratio of th~ output set 8~10 is higher than the ratio of the reaction set 7~9, the output sh~ft 2 rotates in the o~site direction to the input shaft 1;
when it is lower, it turrs in the samé direction.
Alternative end~lates are sho~rn in Figures 3 and 4 for the input endplate 12; end~l2ve 19 is suitable for receiving a stand-ard frame ~otor; endplate 20 is suitable for a flan~e frame motor.
Another embodimen~ of the carrier assembly 11, Ln~ as a du~lex carrier assembly, is sho~n in Figure 5; a seco;~d shaft 6 30 ~-~ associated co~lheels has beer added to balance the arm and to ~ro-~ide 2 stronger tie ~e~ween t:ne reaction co~wheel 9 and ~he ou~ut cogwheel 10; a ~i~er cog~heel 21 is used on the input shaft 1 and lon~er cog ~elts 22 are used on the reaction set and on the 10651~;3 1 outpu~ set. ~he reaction set cog belt 22 is shown in section in r'i~ure 5, as is t~e reaction co~wheel 9; the driver cogwh~els 8 of the output set ~10 are connected with a co~ belt 22 (not shown) to the output co~wheel 10 (not shown). Similarily, a tri-plex assembly, could be used in place of the simplex and duplex assemblies described above.
Chains could be used in place of cog belts in applications where temperature or stress could reduce the life of cog belts.
It can be shown that the invention has the following reduct-ion ratio:
1 ~ N N
N9~7 118NlO
Claims (6)
1. A device for reducing angular speed and for increasing angular torque comprising, in combinations a) three planetaries: an input planetary, an output plan-etary, and a reaction planetary: each planetary comp-rising a related sun and planet wheel, and a flexible force transmitting device operably connecting each of said planet wheels synchronously to said related sun wheel;
b) a planet shaft fast to said planet wheels and operably connecting all of said planetaries;
c) an output shaft fast to said sun wheel of said output planetary;
d) an input means fast to said sun wheel of said input planetary;
e) a frame which supports said output shaft and said input means and allows said output shaft to rotate freely in the frame, and which also supports said sun wheel of said reaction planetary and holds it fast to the frame such that reaction torque is transferred to the frame;
f) a planet shaft carrier means for rotatably supporting said planet shaft while allowing said planet shaft to revolve about an axis concentric to said output shaft.
b) a planet shaft fast to said planet wheels and operably connecting all of said planetaries;
c) an output shaft fast to said sun wheel of said output planetary;
d) an input means fast to said sun wheel of said input planetary;
e) a frame which supports said output shaft and said input means and allows said output shaft to rotate freely in the frame, and which also supports said sun wheel of said reaction planetary and holds it fast to the frame such that reaction torque is transferred to the frame;
f) a planet shaft carrier means for rotatably supporting said planet shaft while allowing said planet shaft to revolve about an axis concentric to said output shaft.
2 A device as defined in Claim 1, wherein said flexible force transmitting devices are in the form of cog belts, and said sun wheels and said planet wheels are in the form of cogwheels,
3. A device as defined in Claim 1, wherein said flexible force transmitting devices of said output planetary and of said reaction planetary are in the form of chains and said related sun wheels and planet wheels are in the form of sprocket wheels and said flexible force transmitting device of said input planetary is in the form of a cog belt, and said input sun wheel and related planet wheel are in the form of cogwheels.
4. A device as defined in Claim 1, wherein said input means is a shaft and said sun wheels and said output shaft are concentric with the input shaft.
5. A device as defined in Claim 1, wherein said input means include a motor with motor shaft, and said sun wheels, said output shaft, and said motor shaft are concentric.
6, A device as defined in Claim 1, wherein said frame is rotatable.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA286,284A CA1065163A (en) | 1977-09-08 | 1977-09-08 | Epicyclic cog belt speed reducer |
| GB7835806A GB2004346B (en) | 1977-09-08 | 1978-09-06 | Device for modifying angular speed or torque |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA286,284A CA1065163A (en) | 1977-09-08 | 1977-09-08 | Epicyclic cog belt speed reducer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1065163A true CA1065163A (en) | 1979-10-30 |
Family
ID=4109479
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA286,284A Expired CA1065163A (en) | 1977-09-08 | 1977-09-08 | Epicyclic cog belt speed reducer |
Country Status (2)
| Country | Link |
|---|---|
| CA (1) | CA1065163A (en) |
| GB (1) | GB2004346B (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2562191B1 (en) * | 1984-03-29 | 1988-08-05 | Delery Creations | MECHANICAL DEVICE FOR DISTRIBUTING THE POWER AND TORQUES OF A MOTOR SHAFT BETWEEN TWO OUTPUT SHAFTS DIRECTLY OR INDIRECTLY DRIVING THE DRIVE WHEELS OF A VEHICLE |
| EP0270430B1 (en) * | 1986-11-24 | 1992-01-02 | Christian Salesse | Speed-transforming mechanism, particularly a speed reducer |
| FR2607214B1 (en) * | 1986-11-24 | 1991-11-08 | Salesse Christian | DEVICE FOR TRANSFORMING MOVEMENTS, IN PARTICULAR SPEED REDUCER |
| DE3719006A1 (en) * | 1987-06-06 | 1988-12-22 | Ver Foerderung Inst Kunststoff | Lightweight transmission with a large reduction |
| GB0906736D0 (en) | 2009-04-21 | 2009-06-03 | Rolls Royce Plc | A drive mechanism |
| CN107664182A (en) * | 2017-11-08 | 2018-02-06 | 杨爱东 | A kind of few poor tooth planet band chain reductor |
-
1977
- 1977-09-08 CA CA286,284A patent/CA1065163A/en not_active Expired
-
1978
- 1978-09-06 GB GB7835806A patent/GB2004346B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB2004346B (en) | 1982-04-21 |
| GB2004346A (en) | 1979-03-28 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5692989A (en) | Self aligning planetary gear transmission & speed reducer | |
| EP0207206B1 (en) | Gearless differential speed reducer | |
| US4628766A (en) | Continuously-variable ratio transmission | |
| US3602070A (en) | Mechanical transmission | |
| EP0090214A1 (en) | Epicyclic transmission having free rolling roller driving elements | |
| US1970251A (en) | Mechanical movement | |
| US4429595A (en) | Motion transmitting device | |
| US3935750A (en) | Counterbalanced mechanical speed-change mechanism | |
| CN1041454C (en) | mechanical transmission | |
| CA1065163A (en) | Epicyclic cog belt speed reducer | |
| US3889554A (en) | Roller transmission | |
| US4542664A (en) | Gear transmission | |
| JPH0242232A (en) | Composite pinion number difference planet-gear reduction gear and variable speed gear box | |
| EP0058631A1 (en) | Power transmission unit with infinite speeds | |
| US4235129A (en) | Speed reduction mechanism | |
| US3851545A (en) | Continuously variable transmission | |
| CA1181260A (en) | Variable speed rotary power transmission | |
| EP3143305B1 (en) | Orbitless gearbox | |
| JPS62288749A (en) | Gear drive having gear ratio variable in stepless manner | |
| US1910777A (en) | Epicyclic gearing | |
| SU1753101A1 (en) | Planetary precision gear | |
| RU2805893C1 (en) | Disc-type variable drive | |
| US3741041A (en) | Speed reduction gear assembly | |
| EP4040015B1 (en) | Compact epicyclic gearing | |
| US4408502A (en) | Traction roller transmission |