Motor vehicles – Special wheel base – Having only two wheels
Reexamination Certificate
1997-12-11
2001-03-13
Hurley, Kevin (Department: 3619)
Motor vehicles
Special wheel base
Having only two wheels
C180S065510, C180S068100
Reexamination Certificate
active
06199652
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a drive wheel assembly for a scooter. More particularly, the invention relates to a scooter wheel driven by a motor housed in a swing arm and directly engaged to a transmission mounted within a sealed but vented gearbox housing that rotates with the wheel, with a heat dissipating member of the swing arm in thermally conductive association with the motor, and in which a second swing arm may be pivoted away from a wheel axle about an axis transverse to the scooter to ease removal of a wheel rim.
BACKGROUND OF THE INVENTION
As exacerbation of air pollution by large numbers of internal combustion vehicles has become a significant concern in large cities, efforts are being made worldwide to provide efficient electric powered vehicles which do not discharge pollutant emissions. Large cities in developing countries which include high concentrations of scooters powered by two stroke engines are particularly affected by vehicle pollution. These two stroke scooters produce large quantities of pollutants and significant noise. Electric powered scooters, on the other hand, offer a means of transportation that emits substantially no pollutants and produces very little noise.
Electric-powered two-wheeled vehicles have been developed. For instance, U.S. Pat. No. 5,272,938 teaches a bicycle with an electric motor mounted inside a front wheel. The motor is disposed within a housing. The motor spins a sun wheel, which spins three planet wheels meshed therewith. The planet wheels are meshed with and rotate against a ring gear that is rotationally fixed to an axle, which is fixed to the bicycle fork. Shafts of the planet wheels are fixed to a swivel block. The rotation of the planet wheels against the fixed ring gear causes the swivel block to rotate about the axle. Through a clutch wheel, the rotating swivel block rotates the housing. The housing is formed from two halves of equal diameter. Wheel spokes are attached to the housing through both housing halves. Thus, rotation of the housing causes the bicycle spokes and wheel to turn, propelling the bicycle.
In the arrangement taught in the '938 patent, however, the motor is unusually thin to fit unobtrusively within the wheel. This arrangement precludes an ideally shaped motor, which is significantly wider and more powerful.
Other electric powered vehicles are also taught, for example in U.S. Pat. No. 5,322,141. This reference shows an electric motor housed within a closed casing that is connected to a passenger carrying vehicle through suspension members which are pivoted laterally from the vehicle and from the casing. A shock absorber absorbs mechanical shocks between the casing and the vehicle.
The arrangement taught fails to take advantage of the suspension members to dissipate heat from the motor. Additionally, this teaching is unsuitable for a scooter or other small vehicles in which swing arms face aft and pivot parallel to the wheel about an axis transverse to the vehicle.
U.S. Pat. No. 4,132,281 discloses a motorcycle drive wheel that is connected on one side to a vehicle frame and on the other side to an arm. A motor is disposed within the wheel and attached to the arm through a pivot. The pivot is fixed to a concave side of the arm. Thus, to change a tire, the arm must be moved laterally away from the wheel, parallel to the axis of rotation of the wheel, to permit removal of the tire.
U.S. Pat. Nos. 5,613,569 and 5,647,450 teach electrically powered scooters, each with an electric motor placed in a pivotable swing power unit attached to a main frame and to a wheel. The motor is located at the end of the swing unit attached to the body. As explained in the '569 patent, this placement requires a transmission to provide power to the wheel disposed within the swing unit, such as a belt. The remote placement of the motor from the wheel and the long transmission reduces the potential efficiency of the drive system.
U.S. Pat. No. 3,387,502 teaches a gear reduction drive unit for heavy off-road work vehicles with electric motors. The reference shows a planetary drive system with an outer oil reservoir and a sump chamber with passages formed therebetween. Turbulence generated as the wheel turns lubricates the moving parts and particles reaching the sump chamber remain separated from the gears. However, teachings are not present that provide adequate equalization of pressures between the atmosphere and within the gearbox so that the gearbox may be sealed with lubricant for life.
An efficient drive wheel assembly is needed for a scooter that takes advantage of increased surface areas for dissipating motor heat, and in which wheel removal is easily accomplished, and with adequate venting within a gearbox to provide atmospheric pressures therein.
SUMMARY OF THE INVENTION
The invention provides a vehicle drive assembly for a drivable wheel of an electrically powered scooter. First and second swing arms are connectable to a portion of the scooter, such as a scooter body, to support the body on a wheel. The swing arms are pivotable about an axis transverse to the scooter body and are configured with shock absorbers to absorb mechanical shocks between the wheel and the body.
The first swing arm includes a heat dissipating member. A motor, which is preferably housed within the first swing arm, is in thermally conductive association with the heat dissipating member and is configured and positioned to drive the wheel. The heat dissipating member is configured to dissipate heat generated by the motor.
In the preferred embodiment of the invention, this heat dissipating member includes a plurality of cooling fins extending from the swing arm and exposed to ambient air. To improve cooling efficiency, the cooling fins are generally aligned with predominant local airflow around the fins when the motor is driving the vehicle.
Preferably, the swing arm has an elongated portion that extends substantially between the wheel and the body, with the heat dissipating member located at least in this elongated portion. In addition, the heat dissipating member is preferably disposed at top and bottom sides of the swing arm, and may also be located on the sides.
First and second gearbox halves form a gearbox housing in the wheel, with both halves configured and dimensioned for structurally supporting the transmission. The first gearbox half preferably has a diameter larger than the second gearbox half. A transmission is housed within the gearbox housing and is associatable with a driven shaft, preferably a motor shaft, to transmit torque between the shaft and the gearbox housing. A wheel rim is releasably fixable to the first gearbox half, and preferably only to this half, and transmits torque between the gearbox housing and a road surface through a road engaging member.
This road engaging member is preferably a tire that attaches to the wheel rim, and the wheel rim defines a central opening that is larger than the second gearbox half. Thus, the wheel rim is detachable from the first gearbox half with the second gearbox half received through the rim opening, while the transmission remains assembled.
The gearbox and transmission are internally lubricated. The gearbox housing is configured for containing lubricant and thus has a lubricant-sealed interior. A lubricant seal is formed between the gearbox housing and a vehicle supporting member, such as the first swing arm. An axial opening in the housing communicates the housing interior with the swing arm. The motor shaft extends into both the swing arm and the housing opening. Additionally, the swing arm includes a vent that communicates the housing opening with the atmosphere, equalizing pressures inside and outside the housing. The vent preferably extends through a wall of the swing arm adjacent the gearbox housing and has a vent opening communicating with the atmosphere at a top portion of the wall, and thus remains generally upright with respect to the scooter.
An annular seal is located between the gearbox halves to seal lubricant radially inside the seal.
Flanary Ronald G.
Greiss Bernd
Mastroianni Cesare
Piedl Martin C.
Hurley Kevin
Pennie & Edmonds LLP
Vectrix Corporation
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