This relates to an electric assist rear hub whose planetary gearing allows the combination of electric motor power and pedaling speed in three power modes: direct drive, motor alone, and variable output speed for the hub wheel; Regenerative braking and complete freewheeling are two more features of this invention.
This field is represented in part in literature and by nearly 100 patents which mostly lack the features needed to provide a complete hybrid drive; many of them are so complex or are built with many highly costly custom parts that any production cost would be prohibitive; several have from three to five sets of gears side by side, making them have a width which could not fit in a normal bike frame.
The prior art in this field showed the following patents:
The always present goal of cycle and assist e-bike is to permit acceptable pedaling rotational speed under a wide variety of riding conditions; even now most rear hub wheel still use from 5 to 10 ratio at the hub requiring an expensive derailleur and a near 2″ wide cassette or freewheel with 5 to 10 sprockets.
Most e-bike rear hubs are Direct Drive from the motor with the drawback of non-negligible drag from the magnetic and electric interference with when riding without electric assist.
A second group is the geared rear hub motor wheel which is lacking any regenerative capability and still requires the full capability of shifting one or two derailleurs plus controlling the e-bike functions.
A new group is rear hub wheel with wireless control and batteries and controller located inside the wheel hub; here many manufacturers use a single chain or timing belt which limits the bike to mostly flat or urban applications, a few others still carry the multiple sprockets and derailleurs.
The present invention is an e-bike rear hub built with mass produced components following a precise configuration allowing several components to be located concentric to each other permitting the use of Direct Drive or Geared Motor combined with one extra planetary set and several one-way bearings, in order to produce a Multi Mode E-BIKE Hub Wheel giving four distinct modes of operation:
This is accomplished with the pedaling power driving a single sprocket or timing pulley at the rear hub; the non-rotating hub shaft is supporting a sleeve where the cyclist rotates the power drive sleeve while a first one-way bearing drives the hub casing providing Direct Drive; on this sleeve, a second one-way bearing drives a sun gear which meshes with the planets whose carrier is fastened to the hub casing in order to propel the rear wheel when the power is provided to the ring gear by the e-bike motor, for either motor drive alone or under Assist Drive and Variable Speed Overdrive; Regenerative Braking is provided by locking the planetary set as a single unit similarly to the Electric Direct Drive rear wheel hub.
It is a foremost object of this invention to provide a rear e-bike wheel hub which is highly efficient and performs similarly to a hybrid car powertrain; either using one of two power sources, human power or electric power, or using the two powers combined together for hill climbing or higher speed riding.
A second object is to permit the user to control the level of power (1-2-3) with one hand at the handle bar near one brake lever and the other hand near the other brake lever to activate the throttle without having to touch the usual console located at the center of the handlebar; the only other control is a push button which activates regenerative braking.
A third object and advantage of this invention is the combination of the current e-bike hub with an extra low cost bicycle planetary and basic small size industrial, or bicycle one-way clutch in a specific configuration to allow the manufacturing of a better highly advanced and competitive e-bike rear hub.
A fourth object and advantage is to allow the use of a cleaner timing belt instead of a chain with the single ratio crank to rear wheel for urban and other uses; a crankset with two gears and front derailleur will provide the necessary low ratio for a cyclist riding in a very hilly area.
This invention's objects, features and advantages will be better understood in consideration of the detailed description of several embodiments illustrated in the drawings and pictures, in which:
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According to the aforementioned structural combination, the novel electric hybrid rear hub allows the cyclist to choose a preferred rotating speed:
1st scenario: one direct drive gear which is comfortable to pedal, example: 60-80 rpm which translates to 15-20 miles per hour. This translates to around 120-200 watts, which an average cyclist can produce via the one-way clutch 32 which drives the hub casing 36 and bicycle wheel. Under pedaling alone the direct drive motor is allowed to rest still because the ring 26 fastened to the motor does not rotate and is compensated by the sun gear 38 which turns freely at 3 times the speed of the wheel for a sun-to-ring ratio of 1:2, at 15 miles per hour or 3 rotations per second, 180 rotations per minute, this is 540 rpm which is much more efficient than rotating the motor at 180 rpm and resulting magnetic interaction.
2nd scenario: when the motor helps the propulsion but the motor speed is equal to the sprocket speed and therefore can assist as low as no power or as high as twice the cyclist power, example: climbing a hill at 15-20 miles per hour with the total power ranging from 300 watts to 900 watts; the motor power load would be 200 to 600 watts, respectively and human pedaling power would be 100 and 300 watts respectively which is under the US Federal limit of 750 for motor power.
3rd scenario: when the motor rotates faster than the pedaling sprocket. Extreme condition is no pedaling and the hub wheel rotates at ⅔ the speed of the motor (this means more torque than a similar motor directly driving the hub wheel combination). Also, this means the electric motor can provide up to 100% of the power or as little as none. The speed relationship of the wheel is a combination of the sun gear and ring gear speed. As example, if on electric alone, 20 miles per hour is the maximum cruising speed, adding pedaling will bring that speed to 30 miles per hour. Again this follows the Federal limit of 20 miles per hour for no pedaling. In summary the motor assist can be from 0% to 100% and the direct speed of 15 miles per hour can be maintained in any situation; then variation from 15 to 30 miles per hour can be achieved by simple motor speed variation.
Under load sharing, with the ring gear turning faster than the human power sprocket, the cyclist power is carried by the sun gear 40 while the motor power is applied to the ring gear 26 and the speed of the output planetary drives the wheel hub at a higher speed than the human sprocket 28 and slower than the motor ring gears; during that time the one-way clutch 34 is running freely.
The hub casing 36 is fastened together by a series of bolts 48, similarly, the ring 21 is fastened to the flange 22 by a set of bolts 64; the axle 12 is completed by a sleeve 50 and on the other end a locking ring 52.
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Different than the embodiment is the high speed motor output which is the sun-gear 158 driven directly by a flange disc 121; receiving that power is a planetary holder flange 164 where a one-way clutch 166 is fastened and holds solidly a set of planet axles 168, a set of planets 170 which transmit their rotational torque and speed to a ring gear 171 which is fastened to a large spacer flange 174 which is free rotating on a thin large bearing 176.
The speed and power of the ring gear 172 via the spacer flange 174 to a second ring gear 126 which plays the same role as the ring gear 26 of
It is to be noted that the ring gears 172 and 126 are fastened to the spacer flange 174 by numerous bolts 178, also the large diameter bearing 176 is fastened at its inside diameter by a circle ring 180 and at its outer diameter by a second circle ring 182.
It should be noted that the gear motor hub sun gear rotation is always reversed in relation to the bicycle wheel since the planetary and the planets reverse the rotation to the ring gear.
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A one-way bearing 239 allows the power and rotation of an external source via the sprocket 221 to be transferred to the sleeve hub 223 and in a single forward motion to the ring gear 226.
This one-way bearing 239 becomes the key component permitting: either a first scenario propulsion of the hub wheel by only the sprocket 228; or in a second scenario by only the sprocket 221; or in a third scenario by both the sprocket 228 & 221; or in a fourth scenario it permits the hub wheel to freewheel without any motion of any of the two sprockets, in such case the sun gear would not rotate, the planetary holder rotates at the same speed as the wheel and the ring gear would rotate at 1.5 times the speed of the wheel for a ratio of 1:2 between the sun gear/ring gear diameter.
On the power hub 230 is a second one-way clutch 270 which prevents backward rotation of the sprocket 228 when the only power source is the ring gear 226 powered by the large sprockets 221 and permit electric mode without negative torque to the bike user.
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A set of solenoids 70 are fastened to the flange 22 permitting energization when needed via a group of insulated buttons 76 and a spring loaded ring 74 and a set of brushes 72.
The buttons 76 are fastened to the disc 16 and hub 14 which permit electrical connection with the controller via wire tube 60.
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In the new sensor shown in
With the new invention when running with the output ring gear rotating faster than the sun gear, the variation of speed of pedaling is competing with the torque of the electric motor, therefore it is necessary to lower the power of the motor during the weak dead center portion of the pedaling. This problem is solved by the new magnet sensor with variation of position of the magnets which instruct the controller to vary its power in relation to the pedaling position.
Even more, if adjusted properly the new speed sensor disc could allow the PAS to permit what is called the dead center pedaling portion to be done faster than the push down section which provides the large portion of the pedaling energy and this gives a more dynamic pedaling motion.
Advanced controller as seen on
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It is to be understood that many mechanical fastenings of the component are done following general mechanical and machinist procedure and therefore it is to be understood that many fastenings which were not shown in the description are either press fit or threaded, and sometimes with lock tight. Sometimes two of the components could be welded together when permitted.
From the previous description it is readily apparent that a low cost and compact planetary transmission mechanism can be incorporated into a rear e-bike hub wheel which could be built and appreciated by those skilled in the art. It is to be understood that various changes and modifications may be made without departing from the spirit and scope of the invention.
This application claims the benefit of the U.S. Provisional Application Ser. No. 62/070,299, filed on Aug. 20, 2014, which is herein incorporated by reference in its entirety.