Abstract:
A compact, self contained hub motor to be mounted on a wheeled vehicle wheel in order for a wheeled vehicle to be driven electrically. The wheel has a hub within which is mounted a stationary center shaft. Mounted about the center shaft is a motor housing which is rotationally mounted on the center shaft. The motor housing has an internal chamber. Within the internal chamber is mounted a motor. Operation of the motor causes rotation of the motor housing which simultaneously drives the wheeled vehicle wheel on which the motor is mounted.

Description:
BACKGROUND OF THE INVENTION 
     1) Field of the Invention 
     The field of this invention relates to electric motors that are designed to be used in conjunction with a bicycle wheel of a bicycle, tricycle or any other similar wheeled vehicle, and more particularly to a compact, small in size, powerful electric motor which has an internal controller which is mounted at the hub of the wheel which is being driven. 
     2) Description of the Prior Art 
     Although the hub motor of the present invention has been found to have particular utility in conjunction with electrically operated bicycles, the motor is also deemed to have utility of other applications such as operating of a scooter, moped, tricycle, wheelchair and other types of manually operated wheeled vehicles as well as within other environments that are unknown to the inventor at this particular time. This invention will be discussed primarily in conjunction with bicycles for description purposes only. 
     Electric motors have been used in the past to operate bicycles electrically. The electric motors of the prior art have been rather large in size and are of relatively heavy weight. It is desirable to have the electric motor to be as small as possible and also to have the motor be as light in weight as possible to thereby keep the overall weight of the bicycle as low as possible. Also, electric bicycles of the prior art have exposed internal components. Bicycles are frequently ridden through adverse weather conditions which can result in water and foreign material, such as mud, contaminating the internal components of the electric motor. 
     Electric motors require the use of an electronic controller which controls the different speeds that the motor is being operated. In the past, it has been common to use a controller that is mounted separate from the motor. This requires an additional structure and requires separate mounting in conjunction with a bicycle being preferable to eliminate the use of this separate structure. 
     SUMMARY OF THE INVENTION 
     The hub motor of the present invention is designed to comprise a small in size, compact motor assembly which is to be mounted in conjunction with the hub of a bicycle wheel. The motor assembly comprises a self contained unit which includes a rotationally driven motor housing that is connected directly to the tire supporting rim of the bicycle wheel. Rotation of the motor housing will result in similar rotation of the tire supporting rim of the bicycle wheel. The motor housing has an internal chamber and within that internal chamber is located a stator and a rotor. The stator is fixedly mounted onto a center shaft which passes through the motor housing which is fixedly mounted to the bicycle frame. The rotor is to be rotated by the electrical energy being supplied to the stator with this rotation being transferred through a drive shaft to a driven gear. This driven gear is mounted within the internal chamber of the motor housing. A one-way clutch is to be mounted between the driven gear and the motor housing so that the normal driving torque of the driven gear will cause rotation of the motor housing but any torque in the opposite direction will not be transferred to the motor housing. 
     One of the primary objectives of the present invention is to construct a motor assembly which is mounted within a motor housing which is mounted at the hub of a bicycle wheel. 
     Another objective of the present invention is to construct a motor assembly for a bicycle wherein the hub motor, controller for the motor and clutch are all mounted within a rotational motor housing to which is to be fixed the tire supporting rim of the wheel of the bicycle. 
     Another objective of the present invention is to construct a motor assembly which can be manufactured at a reasonable cost and thereby sold to the ultimate consumer at a reasonable cost. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a better understanding of the present invention, reference is to be made to the accompanying drawings. There could be utilized alternate embodiments of the present invention which are not shown in the accompanying drawings but are believed to still fall within the scope of this invention. It is to be understood the invention is not limited to the precise arrangement shown in the drawings. 
     FIG. 1 is an external side elevational view of a bicycle within which is incorporated the hub motor assembly of the present invention; 
     FIG. 2 is a cross-sectional view taken through the hub motor assembly of this invention taken along line  2 — 2  of FIG. 1; and 
     FIG. 3 is a cross-sectional view through the hub motor assembly of this invention taken along line  3 — 3  of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring particularly to the drawings, there is shown in FIG. 1 a conventional bicycle  10  which has a tubular frame  12  upon which is mounted a foot operational pedal assembly  14 , a front wheel  16  and a rear wheel  18 . The frame  12  includes a handlebar assembly  20  on which is mounted an electrical switch  22 . The electrical switch  22  is connected by a conductor  24  to a battery  26 . The battery  26  is connected by a cable  28  to the hub motor assembly  30  of this invention. The hub motor assembly  30  is shown mounted in conjunction with the front wheel  16 . However, it is considered to be within the scope of this invention that the hub motor assembly  30  could be mounted in conjunction with the rear wheel  18 . 
     The front wheel  16  includes a rubber tire  32  which is mounted on a tire supporting rim  34 . The tire supporting rim  34  is connected to a series of wire spokes  36 . The inner end of the wire spokes are attached to annular flange  38  and annular flange  40  of a motor housing  42 . Fixedly mounted between the fork members  44  and  46  of the bicycle frame  12  is a center shaft  48 . The ends of the center shaft  48  are threaded with a nut  50  being used to fixedly mount the center shaft  48  to the fork member  44  and the nut  52  being used to fixedly secure the center shaft  48  to the fork member  46 . Mounted on the center shaft  48  are a pair of spaced apart bearing assemblies  54  and  56 . The motor housing  42  is rotationally mounted on bearing assembly  54 . The motor housing  42  includes a removable access plate  43  which is bolted to housing  42  by bolt fasteners  45 . The center shaft  48  has a longitudinal center axis  128 . 
     The center shaft  48  includes a cutout  58 . The cable  28  is to be passed through the cutout  58  to be located within the internal chamber  60  of the motor housing  42 . The cable  28  comprises a plurality of electrical conducting wires like  62 ,  64  and  66  which are connected to electronic components such as component  68 , mounted on a printed circuit board  70 . Note that all the wires are not shown and the number of the wires will vary based on control functions required. Printed circuit board  70  is then fixedly mounted on a mounting plate  72 . The mounting plate  72  is made of heat conductive material like aluminum and is basically disc shaped and is fixedly attached by means of a set screw  74  and a key  76  to the center shaft  48 . One side of the mounting plate  72  abuts against a retaining ring  78  which is fixedly mounted to the center shaft  48 . 
     Integrally formed to the mounting plate  72  is a sleeve  80 . The sleeve  80  has a through opening  82 . Fitted within the sleeve  80  are a pair of bearing assemblies  84  and  86 . Fitted into the bearing assemblies  84  and  86  is a drive shaft  88 . Drive shaft  88  includes a pair of spaced apart annular grooves  90  and  92 . Glue is to be applied within the grooves  90  and  92  with groove  90  to connect with the inner race of bearing assembly  84  and groove  92  connecting with the inner race of bearing assembly  86 . It is the function of the glue to provide a means of further securement of the inner races of the bearing assemblies  90  and  92  so as to affix such to the drive shaft  88 . In order to minimize the creation of noise and provide for smooth rotation of the drive shaft  88  there is mounted a circular leaf spring  94  between annular ridge  96  of the sleeve  80  and the outer race of bearing assembly  86 . This will exert a constant axial torque applying an actual force against retaining ring  98  which is mounted on the drive shaft  88 . The inner race of the bearing assembly  84  abuts against the retaining ring  98 . 
     The drive shaft  88  is capable of being rotated about rotational axis  100 . It is to be noted that the rotational axis  100  is located parallel to the longitudinal center axis  128 . The locating of the axes  100  and  128  parallel provides for smoother operation of the motor. The aft end of the drive shaft  88  includes a spline connection  102  with the forward end of the drive shaft  88  including a spline connection  104 . The spline connection  102  connects with rotor bushing  106 . Rotor bushing  106  is securely mounted onto a cup shaped member which is defined as rotor  108 . Mounted interiorly of the rotor  108  are a series of magnets  110 . These magnets  110  are to be located directly adjacent but slightly spaced from a series of radially located coils  112 . There are multiple numbers of the coils  112  each of which comprises electrically conductive wires that are wound about a series of radially disposed spokes called stator laminations, which are not shown. The coils  112  are connected by leads  114  to the printed circuit board  70 . 
     Spline connection  104  connects with the circular shaped driven gear  116 . The driven gear  116  has a center opening  118 . Press fitted within the center opening  118  is a clutch assembly  120 . The clutch assembly  120  is mounted on sleeve  122  which is an integral part of the motor housing  42 . Clutch assembly  120  is what is termed as a one-way clutch. Driven gear  116  is mounted within a chamber  124  which is defined by a circular shaped stub wall  126 . The stub wall  126  is integrally connected to the motor housing  42  and is located within the internal chamber  60 . 
     The operation of the hub motor assembly  30  of this invention is as follows: When the bicycle rider wishes to drive the bicycle  10  by means of electrical power, the user is to manually move switch  22  from the off position to the on position. This will result in electrical power from the battery  26  being supplied through the cable  28  to the printed circuit board  70  and then through lead wires  114  to the coils  112 . This will cause the rotor  108  to be rotated due to the forming of a magnetic field between the coils  112  and the magnets  110 . This rotation of the rotor  108  will cause the rotor bushing  106  to rotate which rotates the drive shaft  88 . The rotation of the drive shaft  88  will cause the driven gear  116  to be rotated. In comparing the size between the spline connection  102  and the driven gear  116 , it can be seen that there will be a substantial number of revolutions of the drive shaft  88  for each revolution of the driven gear  116 . This gear reduction is required so that the motor housing  42  will be rotated at a substantial number of less revolutions per minute than the drive shaft  88 . Let it be assumed that the driven gear  116  is rotated clockwise in order to achieve the desirable similar rotation of the motor housing  42  which in turn will produce, in essence, the same rotation of the front tire  16  propelling the bicycle  10  on the supporting surface  130 . It is to be noted that the driven gear  116  is mounted by  132  and  120  one-way clutch assembly  132 , the construction of which is deemed to be conventional, relative to the sleeve  122 . When the switch  22  is moved to the off position and power is not being transmitted to the coils  112 , the rotor  108  begins to slow down in rotation and will actually come to a stop in a short period of time. The front wheel  16  of the bicycle  10  will continue to rotate which is permitted by means of the one-way clutch  120 . 
     In an alternate embodiment of this invention, which is not shown in the drawings, the one-way clutch  120  could be mounted between the drive shaft  88  and the sleeve  80 . In some installations, this mounting would be preferred as it further compacts the overall structure of the present invention so that the hub motor assembly  30  can actually be smaller in size.