Motor vehicles – Special wheel base – Having only two wheels
Reexamination Certificate
1999-04-30
2001-08-07
Oberleitner, Robert J. (Department: 3613)
Motor vehicles
Special wheel base
Having only two wheels
C180S205200
Reexamination Certificate
active
06269898
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an electric motor bicycle, and more particularly to a unitary self-contained direct drive power module (or “unitary power module”) for electric bicycles or other vehicles. The invention also includes a kit for converting a standard bicycle into an electric bicycle by use of the unitary power module.
By way of background information, and turning now to the drawings, FIG.
19
(
a
) illustrates a standard bicycle
100
(“or bicycle”), which is a two wheeled vehicle comprised typically of a front steering wheel
102
and a rear wheel
104
, which may be attached to the frame by quick-disconnect units
105
. The standard bicycle
100
includes a frame assembly
106
having a head tube
108
which journals a front fork
110
for steering via handle bars
109
by a rider of the bicycle
100
. As illustrated in FIG.
19
(
b
), the rear wheel
104
is journalled at the rear end of the frame
106
by a pair of rear stays (or “dropouts”)
112
. A seat tube
111
is carried by the frame
106
adjacent the rear wheel
104
and a seat post
113
upon which a saddle type seat
115
is positioned thereon to accommodate a rider.
In the standard bicycle
100
, a horizontally oriented journal (or crank journal)
117
is positioned beneath the seat tube
111
which supports a rider “propelled” drive mechanism
120
. The drive mechanism
120
generally comprises a crank
123
journalled in the crank journal
117
, which includes a chain sprocket
129
having a plurality of teeth, together with the crank
123
positioned therein with along with pedals
125
rotatably journalled at each end
127
of the crank
123
.
Each wheel typically consists of a tire
114
mounted on a rigid rim
116
, an axle
118
, a hub mechanism (or “hub”)
122
and spokes
124
connecting the rigid rim
116
to the hub
122
to form an axle/hub assembly
121
. The hub
122
surrounds the axle
118
and is free to rotate about the axle
118
through a bearing assembly
126
(not shown). The tire/rim assembly
128
is attached to the hub
122
through an assembly of the spokes
124
which are assembled in a woven pattern
130
to form a wheel/hub assembly
140
. This woven pattern
130
of spokes has relatively few variations with a large quantity of existing bicycle wheels being common in using the same or similar thirty-six or thirty-four spoke weave pattern
130
. A target “chain” sprocket
150
is mounted about the rear wheel
104
, and is connected to the crank sprocket
129
by a chain
152
whereby application of power by the rider on the pedals
125
propels the bicycle
100
. A derailleur
154
is often substituted for the single target sprocket
150
(or target sprocket), and may have a plurality of sprockets
156
,
158
,
160
,
162
,
164
and
166
(illustrated in
FIG. 9
) to provide variable gearing for rider comfort when either starting or climbing hills or for rider efficiency.
One of the features of a bicycle, is the ability of the wheel to be removed for servicing, such as repairing a flat. As described above, the typical bicycle wheel is constructed of a tire/rim assembly connected to the hub through a series of woven spokes. The hub rides on the axle of the wheel using a bearing assembly. The axle/hub assembly typically has rather loose manufacturing tolerances and as such provides a poor reference frame for the propulsion elements of prior systems. This occurs because bicycles are typically high rate, low-cost, manufactured consumer products, whereby the tolerances of components are not as high as a high quality mechanism. The majority of bicycles sold in the world and in use are in the lower or looser tolerance ranges. Also, when the wheel (or tire) is repaired and then replaced in the dropouts of the frame, the axle can become slightly cocked with respect to the frame. As such, tolerances for the mounting slots of the wheel axle allow for a wide latitude of assembly. The loose manufacturing tolerances of the axle and axle/hub bearings is typical of such low-cost mechanisms. These large tolerances of wheel and bicycle frame components present a significant problem in the design of reliable direct drive propulsion systems where various components of the system are mounted on different parts of the bicycle (e.g., on the frame, on the axle, etc.)
If the various components of the propulsion system are mounted on bicycle components, which have loose tolerances in reference to each other, then the propulsion system suffers (or will suffer) from these same poor alignment tolerances with rough usage. In order to avoid excessive wear, reduced efficiency, and reduced performance as a result of such loose tolerances, an effective propulsion system should ideally utilize a design which is independent of such loose tolerances in the axle/hub assembly of the bicycle as well as the changing tolerances relative to the frame. It is this design concept which forms this invention.
In the past, electric propulsion systems for bicycles have been implemented through a variety of methods which utilized electric motor power to either supplement or replace the above rider drive mechanism in propelling the bicycle. For example, these methods include friction roller drives, belt drives, gear drives, and chain drives. For example, friction drives typically involve the application of an electric motor or “the drive source” to a wheel or “the target mechanism” through a roller mechanism. The roller may be directly attached to the drive source or through a clutch mechanism. The roller transfers the drive source energy through the contact of the roller on the target wheel through friction between their respective surfaces. This type of drive system suffers from mechanical losses associated with slippage between the roller mechanism and the target wheel as a result of reduced friction and from the energy required to compress the rubber tire. Performance in moisture, rain, snow and mud is marginal at best.
By way of further example, electric bicycles having direct drive systems, such as belt, gear and chain drives typically provide higher energy coupling efficiencies than the roller friction drive systems. These systems however require a high degree of mechanical integrity in the geometry of drive components. For instance, there needs to be sufficient tension in the belt and chain of the belt and chain drive systems and the proper alignment or meshing of the gears in the gear drive system. Proper and exact mechanical alignment must be maintained rigidly with shock and many tire and wheel repairs in order to extend the life of the unit.
There have been a number of designs, which can provide direct coupling between an electric motor(s) mounted externally to the rear bicycle wheel and the axle of the wheel. For example, a motor can be mounted either on the diagonal or horizontal rear members (or “stays”) of the frame. A direct coupling in these cases can be effected through a
90
-degree bevel gear between a shaft from the motor and the axle-hub assembly. In this case, external shocks will cause gear wear. Further, it is difficult to remove the rear wheel for repair. The drive can be effected through a chain, which is better but still mechanically complex and subject to the same kind of problems. It is also difficult to achieve the right reduction ratios between the RPM of typical motors and that of the rear wheel, typically between 10:1 and 25:1. A motor can be mounted above the rear wheel and drive a very large “sprocket” of diameter almost as large as the wheel diameter. Such systems have been demonstrated but have not been accepted because they are clumsy, top-heavy and subject to relative dislocation of the elements.
Other direct drives have been reduced to practice with the motor mounted in the neighborhood of the pedal crank. These can be coupled to the rear wheel by a gear drive with suitable clutches within the crank housing and thence through the usual bicycle chain or through a separate long chain to a separate sprocket on the rear wheel. They can also be coupled to
Bank Devin S.
Currie Malcolm R.
Mayer Richard A.
Terr Seth A.
Widmann Bruce S.
Bartz C. T.
Currie Technologies Inc.
McDermott & Will & Emery
Oberleitner Robert J.
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