Multiple Planetary Gear Assembly with Limited Slip Transmission
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Solution Overview
Problem
Current gear systems in zero turn riding mowers and similar mobile equipment face issues with turf damage and poor traction on side hills and wet grass, making control challenging.
Innovation Solution
A multiple planetary gear assembly with a limited slip transmission system that receives two inputs (propelling and steering) and provides two outputs, allowing for simultaneous or opposing wheel speeds, enhancing traction and control by preventing one wheel from slipping relative to the other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single wheel spins to enable turning, then the mower can change direction, but the turf is damaged
Solution Approach 1:
The patent employs a limited-slip differential mechanism that dynamically adjusts the speed difference between left and right wheels based on operating conditions. The differential allows wheels to rotate at different speeds during turning while the limited-slip mechanism prevents excessive speed differentiation that causes turf damage, creating a dynamic balance between maneuverability and turf protection
Solution Approach 2:
The patent changes the operational parameters of the wheel speeds by using a controlled speed differential mechanism. Instead of allowing one wheel to spin freely at high speed during turning, the system maintains both wheels rotating at controlled speeds with a limited differential, thereby reducing turf damage while preserving turning capability
2Ease of operation
If conventional steering mechanism is used, then the mower can turn, but control on side hills and wet grass is unfavorable
Solution Approach 1:
The limited-slip differential mechanism dynamically responds to traction conditions by automatically adjusting the distribution of driving force between wheels. On side hills or wet grass where one wheel may lose traction, the mechanism maintains controlled speed differential, preventing loss of control and improving reliability of steering operation
Solution Approach 2:
The differential mechanism provides inherent feedback control by sensing the traction conditions through the speed difference between wheels and automatically adjusting power distribution. When one wheel slips or loses traction on side hills or wet grass, the mechanism responds by reducing speed differential, thereby maintaining control stability without requiring external sensors or active control systems
3Speed
If one wheel turns more rapidly than the other, then the mower moves along a curved path, but ground traction is lost
Solution Approach 1:
The system dynamically controls the speed differential between wheels to achieve curved paths while maintaining traction. The limited-slip mechanism allows sufficient speed difference for turning but prevents excessive differential that would cause wheel spin and traction loss, optimizing both curving capability and traction maintenance
Solution Approach 2:
The patent optimizes the wheel speed parameters by implementing a controlled differential mechanism. Instead of allowing large speed differences that cause traction loss, the system maintains speed differential within optimal ranges that enable curving while preserving ground traction through the limited-slip constraint
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
The solution significantly reduces turf damage and improves ground traction, enabling better control on side hills and wet grass by allowing additive inputs that define output speeds, thus enhancing maneuverability and stability.
Implementation Method 1
Mechanical advantage is a measure of the force amplification achieved by using a tool, mechanical device or machine system. Gear systems have proven to be one of the most effective machines in achieving mechanical advantage.
Implementation Method 2
The present invention is a multiple planetary gear assembly with a limited slip transmission system
Implementation Method 3
the ground traction between the wheels of the vehicle and the turf is better maintained. As a result, a user can control the mobile equipment on wet grass or on side hills much more effectively
Data Source
AI summary
A gear assembly with two inputs and two outputs which can be used on zero turn riding mowers or similar vehicles. The first input is a propelling input and the second input is a steering input. The assembly contains a planet carrier, a first planetary gear assembly, and a second planetary gear assembly. The propelling input is engaged with the planet carrier. The first and second planetary gear assemblies contain a ring gear. The steering input is engaged with the ring gears. The steering input is either a helical bevel gear, straight bevel gear, or a gear train. In another version, the gear assembly can have two planet carriers connected externally to the planetary gear assemblies. In this instance, a central gear is used in between the first planetary gear assembly and the second planetary gear assembly to connect the sun gears.