Offset Planetary Gear Reducer for Utility Vehicle Powertrain
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Solution Overview
Problem
Traditional Skid-Steer Loader machines rely heavily on hydraulic systems, which are inefficient in terms of space, weight, and cost, as they require large engines and transmissions to provide torque, whereas electric motors, especially high-speed AC motors, can offer more compact and efficient solutions.
Innovation Solution
The use of offset planetary gear reducers allows for the placement of high-speed electric motors side by side, enabling efficient torque production at the wheels with reduced space and weight, utilizing high-speed AC, DC, hydraulic, or pneumatic motors, and optimizing the use of space for batteries and controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional hydraulic systems are used to power Skid-Steer Loader machines, then sufficient torque can be produced at the wheels, but the system requires large engines and transmissions, increasing space, weight, and cost
Solution Approach 1:
The patent replaces the traditional hydraulic powertrain system with an electric motor system. Electric motors directly produce torque at the wheels without requiring large hydraulic pumps, engines, or transmissions, thereby reducing the weight of powertrain components while maintaining sufficient torque production capability
Solution Approach 2:
The patent changes the fundamental operating parameters by using electric motors that operate at different speeds than traditional hydraulic systems. High-speed electric motors can be paired with gear reducers to achieve the necessary torque at the wheels, allowing for a more compact and lighter powertrain design
2Weight of stationary object
If high-speed electric motors are used, then space and weight are reduced, but the motors produce high speed with lower torque that must be converted to high torque at the wheels
Solution Approach 1:
The patent introduces gear reducers as intermediary components between the high-speed electric motors and the wheels. The gear reducers convert the high speed, low torque output of the electric motors into the low speed, high torque required at the wheels, serving as a mechanical mediator that resolves the torque-speed mismatch
Solution Approach 2:
The patent adds a rotational speed reduction dimension through the use of gear reducers. By introducing this additional stage of speed reduction, the system can use lightweight high-speed motors while still achieving the necessary torque at the wheels through the dimensional transformation of speed to torque
3Area of stationary object
If two high-speed electric motors are placed side by side, then space is optimized for batteries and controls, but the motors must be offset to drive the wheel shafts effectively
Solution Approach 1:
The patent employs asymmetric positioning of the two electric motors, placing them offset from the centerline of the vehicle. This asymmetric arrangement allows the motors to be positioned side by side for space optimization while their offset locations enable direct coupling to the wheel shafts through appropriately positioned gear reducers and drive chains
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 enables the use of smaller, lighter motors to achieve high torque at the wheels, reducing the overall size and weight of the powertrain while maintaining efficient torque production, thus addressing the inefficiencies of hydraulic systems.
Implementation Method 1
a planetary gear set including a sun gear, planet gears, and a ring gear. The carrier of the planetary gear set includes a spline which intermeshes with a splined output shaft
Implementation Method 2
an offset reduction gear system including a housing, an input shaft, a helical gear set, and a planetary sun pinion inputs to the planetary stage
Data Source
AI summary
A wheel driven utility vehicle includes a frame and two small volume high speed alternating current electric motors arranged side by side for driving the vehicle. Alternatively high speed direct current, hydraulic or pneumatic direct current motors may be used with suitable controls. Each motor has an output shaft which drives an offset planetary gear reducer. Each offset planetary gear reducer is affixed to the electric motor and includes an output carrier interconnected with an output shaft. Each output shaft includes first and second chain drive sprockets which drive chains interconnected with shafts driving the front and rear wheels respectively. Each offset planetary gear reducer enables use of space saving high speed relatively low-torque alternating current electric motors with attendant large speed reductions. Gear reduction enables the production of sufficient torque at the wheels of the vehicle. Applications in addition to utility vehicles are also specifically contemplated.