Hub Motor Arrangement with Offset Planetary Gear Drive
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Solution Overview
Problem
Existing hub motor arrangements for children's vehicles and small, lightweight vehicles are too expensive and heavy, making them unsuitable for providing a desirable operating experience at a reasonable cost.
Innovation Solution
The use of a standard, commercially-available 'off-the-shelf' electric motor with a planetary gear arrangement that includes a sun gear, planet gears, and a ring gear, where the motor is positioned along the central axis and offset laterally to optimize space and reduce weight, allowing for a cost-effective and efficient drive system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a custom or large electric motor arrangement is used in hub motors, then the vehicle propulsion performance is improved, but the hub motor arrangement becomes heavy and expensive
Solution Approach 1:
The patent combines the motor, planetary gear arrangement, and hub into a single integrated hub motor arrangement. The motor is positioned within the hub structure with the planetary gears arranged around the motor shaft, merging multiple components into one compact unit that provides both propulsion and weight reduction
Solution Approach 2:
The planetary gear arrangement is nested around the motor shaft, with planet gears rotating on connecting shafts that extend radially from the motor output. The sun gear is positioned at the center of the planet gears, creating a nested configuration where smaller components are arranged within and around larger ones to maximize space utilization and reduce overall size
2Power
If a custom or large electric motor arrangement is used in hub motors, then the vehicle propulsion performance is improved, but the manufacturing cost increases
Solution Approach 1:
The hub motor arrangement is segmented into distinct functional modules: the motor unit, the planetary gear unit, and the hub structure. This segmentation allows each component to be manufactured separately using standard processes and then assembled, reducing overall manufacturing complexity and cost
Solution Approach 2:
The connecting shafts serve multiple functions: they support the planet gears for rotation, provide structural connection between the sun gear and planet gears, and act as mounting elements for the planet gears. This multi-functionality reduces the total number of components needed and simplifies manufacturing
3Volume of moving object
If the motor is positioned along the central axis and offset laterally, then the space utilization is optimized and weight is reduced, but the gear arrangement complexity increases
Solution Approach 1:
The motor is positioned asymmetrically within the hub, offset laterally from the central axis rather than being centered. This asymmetric positioning optimizes the distribution of components within the hub volume and allows for more efficient packaging of the planetary gear arrangement, reducing overall hub size
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration provides a low-cost, efficient drive system for small vehicles by utilizing a standard motor with higher rotational speed to compensate for reduced torque, resulting in equivalent power and longer battery life, while maintaining a compact design.
Implementation Method 1
A sun gear is driven by a motor and drives the plurality of planet gears
Implementation Method 2
A ring gear is driven by the plurality of planet gears
Data Source
AI summary
A ride-on vehicle, such as for a child, includes a vehicle body and one or more wheels that support the vehicle body relative to a surface. At least one of the wheels includes a hub motor arrangement that provides a drive torque for propelling the vehicle. The hub motor arrangement includes a housing defining an interior space. An axle or other mounting element(s) define an axis of rotation of the housing. Preferably, the axle or other mounting element(s) do not pass completely through the housing. A motor drives the housing through a transmission. Preferably, the motor is a standard, compact motor that is positioned on the axis of rotation and can be laterally offset from a central plane of the housing. In some embodiments, a traction element is carried directly by the housing.