Autonomous Mower Gearbox With Single-Motor Blade and Wheel Drive
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Solution Overview
Problem
Conventional autonomous lawn maintenance vehicles require multiple motors and controllers for each drive wheel and rotating blade, leading to inefficiencies and increased complexity, weight, and cost.
Innovation Solution
A single motor powers both the rotating blade assembly and drive wheels through a gearbox with a planetary gear set and a locking shaft that allows for variable speed and direction control without the need for additional motors or controllers, reducing the number of components and simplifying the system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If multiple dedicated motors and controllers are used for each drive wheel and rotating blade, then each component can be controlled independently, but the system complexity, weight, and cost increase
Solution Approach 1:
The single motor is designed to perform multiple functions by driving both the rotating blade assembly and the drive wheels through different transmission paths. The motor serves as a universal power source that replaces multiple dedicated motors, reducing system complexity while maintaining operational control through a unified power train architecture
Solution Approach 2:
The power transmission system is segmented into different pathways within the housing, allowing the single motor to independently control different components. The rotating blade assembly and drive wheels receive power through separate transmission routes from the same motor, enabling independent control of each function while using a single power source
2Reliability
If multiple motors are used to power each component, then each component receives dedicated power, but the overall weight of the vehicle increases
Solution Approach 1:
Multiple motor units are merged into a single motor that powers all rotating components. The single motor is positioned centrally in the housing and provides power to both the rotating blade assembly and drive wheels through integrated transmission pathways, eliminating the weight of multiple separate motors while maintaining reliable power delivery to each component
3Manufacturing precision
If multiple controllers are used for each motor and component, then precise control is achieved, but the manufacturing cost and assembly time increase
Solution Approach 1:
A single controller is designed to manage the single motor that performs multiple functions. The controller handles all control signals for the rotating blade assembly and drive wheels through the unified power train, reducing the number of controllers needed while maintaining precise control over all components through centralized management
Solution Approach 2:
The control system is segmented to handle different functions through a single controller, with separate control pathways for the rotating blade and drive wheels. This segmentation allows precise control of each component while using a single controller unit, simplifying manufacturing and assembly compared to multiple dedicated controllers
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 simplifies the design, reduces weight and assembly time, and lowers manufacturing costs while maintaining efficient operation and control of the autonomous lawn maintenance vehicle.
Implementation Method 1
a gear box comprising a planetary gear set operably connected to the drive wheel and the motor output shaft. The planetary gear set comprises a ring gear having an outside diameter, wherein said ring gear defines a plurality of cavities at said outside diameter
Implementation Method 2
a locking shaft, wherein said locking shaft is configured to enter a space within one of said plurality of cavities, by rotating between an engaged position and a disengaged position
Data Source
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AI summary
An autonomous mobile work system (20) includes a drive wheel (34) that is connected to a frame (24) and a rotating blade assembly (36). The rotating blade assembly (36) includes a blade assembly axis of rotation (38) and is connected to the frame (24) within a housing (26). The mobile work system (20) further includes a single motor (40) operably connected to the blade assembly (36). The motor (50) includes a motor output shaft (44) and the motor output shaft (44) includes an output shaft axis of rotation (46). The mobile work system (20) still further includes a gear box (50) operably connected to the drive wheel (34) and the motor output shaft (44). The single motor (50) urges rotation of both the rotating blade assembly (36) and the drive wheel (34). The gear box (50) can include a planetary gear set (104) including a ring gear (110) defining cavities (120) at its outside diameter (124). A locking shaft (126) can rotate between an engaged position and a disengaged position with one of the cavities (120).