ELECTRIC BICYCLE

An electric powered bicycle includes front and rear wheels (102, 104) that swivel relative to a midframe (106). The midframe (106) includes a pedal driven generator-motor (108), and each wheel (102, 104) includes a motor-generator. The wheels (102, 104) may swivel to opposite sides of the midframe (106) about 180° to move into a collapsed configuration. Swivel may be on single axis joints (162, 168) with tilted swivel axes. In the collapsed configuration, the bicycle is suitable to be carried and stored and may also be utilized in a unicycle/exercycle configuration. By swiveling the wheels (102, 104) to the same side of the midframe (106) about 90°, the bicycle can be placed into other configurations including a walker, a rolling seat, and a chariot to carry packages or a person.

BACKGROUND

Bicycles comprising front and rear wheels mounted to a frame with handlebars, seat and drive pedals are well known. Also known are bicycles driven by electric motors.

SUMMARY

An electric bicycle comprises a midframe and a pedal driven generator supported by the midframe with pedals extending to opposite sides of the midframe. Each of front and rear wheels comprises a rotating tire. Each wheel is mounted to the midframe with a swivel mount, the wheels being configured to swivel from in-line positions to collapsed positions on opposite sides of the midframe. A handlebar is mounted through a handlebar support to the front wheel and a seat is mounted through a seat support over the rear wheel. A first wheel motor in a first one of the front and rear wheels comprises a stator fixed to the midframe and a rotor that drives the tire of the first wheel. A current source is charged by the pedal driven generator, and electronics control charging of the current source from the pedal driven generator and delivery of power to the wheel motor from the current source.

One or each of the front and rear wheels supports a wheel motor. Each wheel motor may comprise a stator fixed to the midframe and a rotor that drives the tire of the wheel. Each wheel motor may also be configured to operate as a generator. The pedal driven generator may also be operable as a motor.

The bicycle may be collapsed to the extent that the wheels are positioned to roll in parallel directions. To that end with simple joints, each swivel mount may comprise a single axis joint that swivels about a tilted swivel axis.

Each stator may comprise opposed rings forming a wheel rim, and the rotor may be positioned between the stator rings and support the tire. The center region of the wheel within the stator may be open. The pedal driven generator may comprise a rotor ring to which the pedals are mounted and a stator ring fixed to the midframe. The pedals may pivot to close into an open center region of the generator.

The seat and handlebar may be configured to be repositioned to enable a rider to pedal the bicycle as a unicycle when the wheels are in the collapsed position. In that configuration, the bicycle may be used for exercise in a fixed location or limited area. It may even be configured to stand stationary as the pedals are driven.

As an alternative to the collapsed position, the bicycle may be configurable to swivel the front and rear wheels to the same side of the midframe, perpendicular to the midframe. In that configuration the bicycle may be configured as a walker with the handlebar and seat removed, the handlebar support and seat support serving as handles. Alternatively, a first portion of the midframe to which the front and rear wheels are mounted may be upright and another portion of the midframe pivoted from the first portion to serve as a seat. As another alternative, after the wheels are swiveled to the same side of the midframe, the wheels are rotated to position the midframe close to and along the ground to support a load. The wheels may be swiveled further to meet each other away from the ground.

The handlebar support and the seat support may each be mounted to swivel about a transverse axis, and the handlebar and seat may each rotate about the respective support.

The midframe may comprise a curved tube coupled at opposite ends to the stator of the front wheel, one end adjacent to the handlebar support. The swivel mount may include a swivel joint in the tube displaced from the handlebar support. The midframe may further comprise a curved tube coupled at opposite ends to the stator of the rear wheel, one end adjacent to the seat support. The swivel mount of the rear wheel may comprise a swivel joint in the tube displaced from the seat support.

DETAILED DESCRIPTION

A description of example embodiments follows.

FIGS. 1 and 2provide a side view and perspective view of an electrically powered bicycle. The bicycle includes a front wheel102, a rear wheel104and a midframe106. The midframe106includes a generator-motor108. The generator-motor108includes a rigid stator110, that forms part of the midframe structure. A rotor112is mounted by ring bearings to the stator to rotate within the stator. The rotor112supports pedals114and116to enable a user to rotate the rotor.

The midframe106also includes a front tubular structure118that may be curved to follow the curve of the wheel102. Similarly, the curved tubular structure120follows the curve of the rear wheel104and completes the midframe. The tubular structures118and120carry batteries or capacitors to be charged by the generator motor108and the two drive wheels102and104as described below. The frame tubes118and120also carry electronics for controlling charging and discharging of the battery or capacitors and to control speed and inertial force applied to the wheels and generator as described below.

A handlebar122is mounted to the top end of the frame tube118through a telescoping support124. The support124is mounted to the tube118through a pivot joint154that allows the handlebar to be tilted forward or backward about a swivel axis202illustrated inFIG. 2.

A seat126is mounted to the upper end of the rear frame tube120through a telescoping support128. The support128is mounted to the tube120through a swivel joint156that swivels about an axis204illustrated inFIG. 2. The seat126is mounted to the support128at a pivot joint that allows the seat to be pivoted about an axis206illustrated inFIG. 2.

The front wheel comprises a circular motor130,138that drives the tire140. The motor includes a left and right stator structures130that are fixed to the frame tube118at the top end by U-shaped bracket132and at the bottom end by U-shaped bracket134. The stator elements are joined at the front of the bike by a U-shaped bracket136. A rotor138mounted by ring bearings within the stator elements is driven by electric current through the stator elements. The tire140is mounted to the rotor138to be driven with the rotor.

A similar wheel structure is provided at the rear of the bicycle. Stator elements142are joined by U-shaped brackets144,146and148and mounted to the ends of the rear frame tube120at the brackets144and146. A rotor150is mounted through ring bearings within the stator elements and drives the rear tire152. Thus, it can be seen that each of the wheels comprises a rigid stator structure that forms a rim of the wheel and that is rigidly coupled to the midframe106. A rotor and tire rotate relative to each set of stator elements to drive the bicycle in forward or reverse motion.

To steer, the front wheel102can be turned relative to the midframe106about a vertical axis158. To that end, a top segment160of the frame tube118is joined to the main body of the frame tube118through a swivel joint162. The stator elements130are mounted to the lower end of the frame tube118through another swivel joint164. By rotating the handlebar122, the front wheel is turned in a manner like that of a conventional bicycle. In addition, the swivel action enables reconfiguration of the bicycle as described in detail below.

Turning of the rear wheel is also enabled, not for turning during operation of the bicycle or for the configuration ofFIG. 1, but for reconfiguring the bicycle as described below. To that end, an upper end segment166of the frame tube120swivels about a vertical axis172at a swivel joint168. Also, the stator elements142are mounted to the lower end of the frame tube120at a swivel joint170.

The rotors138and150can be back driven to become a generator. There are many motor-generator candidate designs including Halbach array, gearless, brushless DC motor-generators and Lorentz force (homopolar or Faraday) motor-generator designs. The design of such motor-generators is well known.

The rotors138,150and stators137,142are connected via slender ring bearings (e.g., incorporating balls, rollers or needles). In another embodiment, these ring bearings could incorporate very low sliding friction materials such as graphene.

Each motor-generator can be independently computer controlled and, when acting as a motor, generates torque which propels the bike using energy stored in the energy storage units located in the tubular frame. When riding down hills, the motor-generators now act as generators and convert the kinetic energy of the bike and rider (and any goods adding to the payload) to stored electrical energy (in the energy storage elements inside the tubular frames).

The rate at which energy is extracted (i.e., power) from the motor-generators acting as generators determines the angular velocity dependent torque (i.e., viscosity) as seen by the internal computer control system hidden in the tubular frame. For example, during a down-hill ride, if the power extracted from the generators is high, then the bike will slow down (via viscous drag exerted by the motor-generators as they harvest energy). Indeed during aggressive braking a maximum power is extracted from the generators (i.e., from both wheels).

Braking at a low speed may use another strategy in which the front and/or rear wheels act as motors to generate torques opposing forward motion (i.e., energy is consumed from the energy storage elements).

The energy storage elements hidden in the tubular frame might be batteries of some type (e.g., lithium ion batteries) having a suitably high power and high energy density, or in another embodiment might be capacitors (having a suitably high power and high energy density).

The smaller mid generator-motor110,112located between the front and rear wheels can be of a similar design to those used in the front and rear wheels.

Torques generated by the bike rider are transmitted via the pedals114,116to the rotor112of the middle generator-motor unit. The electrical energy generated is then stored in either or both types of energy storage units. The rate of energy (power) extracted from the torques generated by the bike rider is computer controlled. This enables the rider to control (via the computers, power electronics and all three motor-generators) the ratio between power exerted by the rider on the pedals and the power delivered to the road surface by the front and rear motor-generators acting as motors. In this way a very wide range of ratios between the human rider input power and the power exerted by the bike on the road may be selected. In this way the system acts like a traditional bicycle gear system but without the need for physical gears. Indeed, the system enables a continuous range of “gear ratios” to be generated.

The rider may control speed and pedal resistance through sensor grips208and210on the handlebar. For example, the user may exert a rotary torque on the right grip to speed up (rotation torque forward) and slow down (rotation torque backward) or exert a rotary torque on the left grip to change the drag force.

Note the absence or need for any chain connecting the pedals to the rear wheels and the absence or need for any physical gears.

It is to be understood that the three motor-generators (front, mid and rear) are controlled with power amplifiers which both deliver power from the energy storage units and conversely can harvest kinetic energy from the motor-generators (front, rear), as driven by the road surface, and deliver that energy to the energy storage units.

A solenoid hidden in the frame tube118at the swivel joint162, and possibly another at swivel joint164, can be activated to lock the front wheel into a variety of positions when the bike is reconfigured into non-traditional form as described below. A similar solenoid is associated with the rear wheel at joint168, and possibly at joint170. This solenoid locks the rear wheel into the forward pointing orientation (as shown) when the bike is in the traditional configuration or into other positions described below.

Multi-axis force sensors embedded in the handlebar support124and the rear seat support, respectively, are used in both traditional (as shown) and nontraditional (as shown in subsequent figures) bike configurations to control the bike by a rider or to allow a human to walk beside the bike and via gentle forces exerted on either the handlebar support of the seat support to guide the bike. The same sensors are used in the nontraditional bike configurations (show below) to issue commands to the bike (such as to set its speed or direction).

FIG. 3shows another embodiment substantially the same as that ofFIGS. 1 and 2except that it additionally includes an additional frame302as part of the midframe. Curved tubes304and306are positioned adjacent to frame tubes118and120, lower tube308is positioned adjacent to the generator-motor108, and an upper tube310bridges the tubes304and306. The additional frame segment302increases rigidity of the frame and provides additional space for power storage batteries and capacitors and for electronics. The frame302also provides additional function in other configurations of the bicycle described below.

FIG. 4illustrates another embodiment that is substantially the same as that ofFIGS. 1 and 2with an alternative mounting of the seat. Here, the telescoping seat support402is mounted at a lower end of an upper segment406of the rear frame tube120at a swivel joint404.FIG. 4also shows the handlebar122and the handlebar support124swiveled forward relative to what is shown inFIG. 1.

FIG. 5illustrates a bicycle identical to that ofFIG. 4with the addition of the additional frame segment302previously shown inFIG. 3.

FIG. 6is a front view of the bicycle ofFIGS. 1 and 2; andFIG. 7is a top view of the bicycle ofFIGS. 1 and 2.

FIGS. 8-11are top views showing the bicycle being folded to reconfigure it into a collapsed configuration. In order to reconfigure the bike in the front and rear, solenoids at swivel joints162and168are temporarily activated to unlock the bike such that the front and rear wheels are free to swivel about their respective swivel axes158and172. Once this is done, the bike rider may swivel the front and rear wheels around their respective swivel axes158,172by almost 180 degrees with the result that the front and rear wheels are adjacent to each other on either side of the midframe106as shown inFIG. 11.

InFIGS. 8-11, the seat126is seen to be relocated and clamped on the frame tube120at a position below the swivel joint168. Accordingly, it does not rotate with the rear wheel104. If the seat were retained at the upper end of segment166of the frame tube120as shown inFIG. 1, it would rotate with the wheel. InFIG. 11, the seat would be shown further to the left and pointing in the reverse direction.

InFIG. 8, the front and rear wheels102,104are swiveled about respective swivel axes158and172toward opposite sides of the midframe106. InFIG. 9, the wheels are swiveled further, and inFIG. 10, the wheels are swiveled almost to their full extent alongside the midframe106.FIG. 11shows the fully collapsed configuration in a top view. InFIG. 11, the pedals extend through the front and rear wheels102,104as enabled by the spokeless wheels that are open in the center region of the wheels.

The bicycle can be collapsed manually, or the motors in the front and rear wheels can aid in (or completely and autonomously execute) this transformation. The front and back wheels are first swiveled a bit off alignment. Then the front wheel is driven in reverse and the back wheel is driven forward in a back a forth motion to achieve the auto-folding.

From the collapsed configuration ofFIG. 11, the bicycle can be further compacted as illustrated in the side view ofFIG. 12. Here, the left pedal114is swiveled up and the right pedal116is swiveled down to position each fully within the open region within the generator-motor108.FIG. 12also shows that the upper frame tube segments160and166extend alongside the wheels102and104. This effect results from the mating surfaces1202,1206of the upper segments160,166to the mainframe tubes118and120being perpendicular to the swivel axes158,172but angled relative to the center axes of the tubes118and120. InFIG. 12, the handlebar has been removed from the handlebar support124, which is now swiveled about the swivel joint154to be close to the wheel102. Similarly, the seat has been removed from the seat support128, which is pivoted about swivel joint156to be close to the rear wheel104. The seat has been placed inside the wheels and may be magnetically coupled to or spring clamped to or otherwise coupled to the wheels to serve as a shoulder pad in carrying the collapsed bicycle on one shoulder. The handlebar122may be clamped to or magnetically or otherwise coupled to one or both wheels. InFIG. 12, it is shown positioned to the right of the wheels.

It can be understood that, if the bicycle were collapsed about vertical axes158,172, the wheels102,104would collide with the midframe106before the wheels and midframe reached a parallel orientation. To collapse the wheels into a parallel configuration, double axis joints162,168can be used. But to avoid the complexity of a double axis joint, the system shown relies on single axis joints162,168where the swivel axes158,172are slightly tilted from vertical, one to one side and the other to the other side. The result is best seen inFIG. 13, which shows an end view of the collapsed bicycle ofFIG. 12. In this view, the wheels102and104are no longer vertical as they were in the standard riding configurations ofFIGS. 1 through 7. With the tilted swivel axes, the wheels are positioned closer together at the upper end but are split apart at the lower end. To allow for the more compact folding, a notch174(FIG. 1) is provided in the frame tube118, and a notch176is provided in the frame tube120. In this folded configuration, the rear wheel104rests in the notch174, and the front wheel102rests in the notch176. The result is a collapsed configuration in which the wheels are no longer parallel but which allows the wheels to roll in parallel directions. The spread of the wheels at ground also leads to greater stability. The wheels close to each other at the top bring the handlebar and seat supports closer together in the axial direction toward a center plane for riding embodiments described below.

FIGS. 14 and 15show alternative positions of the handlebar122coupled to the collapsed bicycle. As before, the handlebar may be clamped or magnetically coupled to one or both folded wheels.

FIGS. 16-19show the bicycle in the collapsed configuration but with the handlebar122and seat126and their respective supports retained at the joints154,156as shown in the standard configuration ofFIG. 1. When first collapsed, both the handlebar and seat would face in reverse directions as the handlebar122is shown inFIG. 11. After collapse, the end segments160and166of the frame tubes118and120are directed toward each other. The seat support128and handlebar support124are offset from each other slightly in the axial direction of the wheels due to the offset of the wheels. To obtain the position shown inFIG. 16, the handle bar122is rotated 180° on its support124, and the support124is swiveled forward, away from the seat, on swivel joint154. Similarly, seat126is rotated 180° on its support128, and the support128is swiveled away from the handlebar on its swivel joint156.

In this configuration, the bicycle may be utilized as a unicycle that has particular application as an exercise bicycle (exercycle) for exercise in a room or other close space. In this exercise configuration, the bicycle can be used to exercise the body by providing a velocity dependent torque to the pedals. The electrical energy generated by the mid motor-generator112,114is stored in the energy storage modules. With gyro and accelerometer sensing, the electronics may retain the unicycle in a stable, stationary position by dithering forward and reverse rotation of the wheels. If needed, the bike in this configuration can be programmed to drive in a circle, figure eight or some other arbitrary path during exercise. Indeed, the path travelled (it might be in a living room, for example) might be coupled to a display, perhaps mounted to the handlebar, of some interesting path (e.g., mountain path) or circuit (e.g., bike race circuit).

FIGS. 17-19provide the top, front and rear views of the unicycle configuration ofFIG. 16.

FIGS. 20-26illustrate walker configurations of the bicycle ofFIG. 3. To obtain this configuration, both wheels102and104are swiveled about swivel joints162,168to the same side of the midframe by 90° and then locked in place. The end segments160and166of the frame tubes118and120also extend to the side at 90°. The pedals114,116are swiveled into the collapsed position within the generator108, and the handlebar and seat are removed. The handlebar support124and seat support128, with their associated torque sensors, extend alongside the wheels as walker handles. The walker is powered and can steer under computer control by differential torques generated by the two wheels. Three axis accelerometers and three axis gyros in the bike control system are used to servo control the bike in this walker configuration to remain in the orientation as shown. A person using the bike in this walker configuration holds the bike via the handlebar support bar124(in one hand) and the seat support bar128(in the other hand). The multi-axis force/torque sensors in supports124and128are used to detect direction and speed commands from the human.

The bicycle in this walker configuration can also function as an autonomous robot (i.e. can function without a human “driver”).

FIG. 21shows an end view of the walker ofFIG. 20;FIG. 22shows a side view of the walker; andFIG. 23shows a top view.

The user of the walker may also simply hold the top bar310of the additional frame segment302of the midframe. In the configuration ofFIG. 24, the midframe addition302is tilted toward the user on pins2401extending through the front frame tube118and rear frame tube120. This moves the top bar310closer to the user for more convenient grasping.

FIG. 25is an end view of the walker ofFIG. 24with the frame addition302tilted toward the user, and additionally shows the handlebar mounted between the front and rear wheels. The handlebar may be mounted by magnetic coupling or spring clamp or other temporary attachment mechanism. The handlebar adds to the rigidity of the system. In a configuration where the midframe addition302is not included, the handle122would then provide an additional feature to be grasped by a user with possible control through the end hand grips208and210.FIG. 26shows a perspective view of the configuration ofFIG. 25.

FIGS. 27-31illustrate yet another configuration of the bicycle, a chariot configuration. Here, the bicycle is configured as inFIG. 20but the wheel stators of the front and rear wheels102and104are rotated 90° about their center axis. This brings the midframe302low, alongside and parallel to the ground. This configuration can be used to transport packages supported on the midframe as illustrated inFIG. 31or a user may stand on the midframe. In the latter case, the handlebar122might be connected between the stators of the wheels102and104to serve as a handlebar with handle grip controls to be gripped by the user. The handlebar support124and the seat support128might still be used by the user, but to avoid having to squat, extensions, not shown, would be added to the supports. In either case, the multi-axis force/torque sensors in the supports124and128are used to detect direction speed commands from the user. The bicycle in this chariot configuration can also function as an autonomous robot (i.e. it can function without a human driver) and might be used for package delivery among other tasks.

FIG. 29shows an end view of the chariot configuration with the handlebar122mounted, andFIG. 30is a side view of the chariot configuration without the handlebar.

FIGS. 32-37illustrate yet another configuration, a compact robotic configuration. This configuration is like the chariot configuration ofFIGS. 27-31, but the wheels102,104have been swiveled further to the same side of the midframe106to meet where they can be clamped together at3202. As with the chariot configuration, this configuration can carry a package as illustrated inFIG. 37and can be operated autonomously.

FIGS. 38-41illustrate a modification of the configuration ofFIGS. 32-37to enable it to be ridden by a human user while also carrying a package on the midframe. To that end, a top bar3802is coupled at the intersection of the wheels at3202by means of a coupling3804. The handlebar122is positioned at one end of the bar3802and the seat126is positioned at the other end of the bar. The unit can be controlled by the handgrips208and2010on the handlebar122.FIG. 38shows a perspective view of this configuration;FIG. 39shows the side view;FIG. 40shows an end view; andFIG. 41shows a top view. As noted, this configuration allows a package to be carried as inFIG. 36. Torque sensors in the handlebar support124may also be used to receive direction and speed commands from the human. As in all other configurations, three axis accelerometers and three axis gyros enable the bicycle control system to keep the bike upright as shown. Also, as in all other configurations the unit may be operated as an autonomous robot without a human driver.

FIGS. 42-46illustrate yet another configuration, a seated configuration. Here, the bicycle is configured as in the walker configuration ofFIGS. 21-24except that the midframe addition302is pivoted on pins2401all the way to a horizontal position. A user may sit on the bar310and control the seated bicycle using the handlebar and seat supports124,128as control handles. As illustrated inFIG. 43, a web4302may be coupled to the frame tubes118and120and to the midframe addition302to increase the comfort of the user with a seat4306and a back4308and also to provide additional support to the midframe edition302through the sides4304of the web.

FIG. 44shows an end view of this configuration without the web;FIG. 45shows a side view of this configuration without the web; and theFIG. 46shows a top view of this configuration without the web.

As with all other configurations, the multi-axis force/torque sensors may be used to detect direction and speed commands from the human user. Accelerometers and gyros may be used to maintain the unit in the stable upright position as illustrated, and the unit may be operated as an autonomous robot without a human driver.

FIG. 47illustrates the electronic and the power components of the bicycle. The front motor-generator4702corresponds to the stator130, rotor138forming the front motor-generator. Rear motor-generator4704corresponds to the rear stator142and rotor150. Pedal generator-motor4706corresponds to the generator-motor108. These motor-generators charge the power storage4708and are powered from the power storage4708through power electronics4710. As previously noted, the power storage may be in batteries, capacitors or a combination of the two. Charge-discharge of the storage and powering of the motor-generators is controlled by a processor4712through the power electronics4710. The processor responds to internal software programming and to external inputs. Inputs include speed control4714which may be obtained from the right grip210of the handlebar122. Stiffness control4716may, for example, be fed from the left grip208. Multidirectional torque input may be obtained from torque sensors4718that may, for example, be mounted in the handlebar support124and seat support128. Accelerometers4720and gyros4722mounted anywhere within the midframe provide inputs to the processor to enable the bicycle to stand in a stable upright position in each of the many configurations. The front and rear solenoids used to lock the swivel joints162,168are controlled by the processor. Other inputs and outputs to and from the processor may also be provided from and to a controller such as an application in a smart phone. The components4708,4710,4712,4720and4722may all be mounted within the base midframe106ofFIGS. 1 and 2and, optionally, in the midframe addition302.