Magnetic Coupling for Blade Rotation Systems

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Solution Overview

Problem

Blade rotation systems in rotary blade turf mowers face issues with shaft seal leakage and failure due to wear and high impact loads, which lead to increased maintenance costs and space constraints from the need for case drain hoses and hardware.

Innovation Solution

A magnetic coupling system replaces the traditional shaft seal, using permanent magnets to transfer rotational motion between the hydraulic gear motor and spindle shaft, eliminating the need for a shaft seal and case drain, and incorporating an automatic torque limiter to prevent damage from high impact loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional shaft seal and case drain system is used, then hydraulic fluid leakage can be managed, but the system complexity increases and maintenance is required

Engineering Contradiction:

Improveshaft seal leakage preventionVSAvoidcase drain hose and hardware

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes the shaft seal and case drain system from the hydraulic gear motor assembly. By extracting these components, the invention eliminates the sources of leakage and the associated complexity of hoses and hardware, while maintaining hydraulic fluid containment through a sealed motor housing design

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical shaft seal system with a magnetic coupling system that transfers rotational motion without mechanical contact across the housing boundary. This substitution eliminates the need for dynamic seals and their associated case drain requirements

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a shaft seal is used to prevent hydraulic fluid leakage, then fluid containment is improved, but the shaft seal wears and fails over time

Engineering Contradiction:

Improvehydraulic fluid containmentVSAvoidshaft seal service life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent extracts the shaft seal from the system by using a magnetic coupling that transfers power without mechanical contact. This removal eliminates the wear mechanism that limits shaft seal service life, as there is no friction or contact between moving parts

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The mechanical contact-based shaft seal is replaced with a magnetic field-based coupling system. This substitution eliminates wear and failure over time, as magnetic fields do not degrade through friction or mechanical stress

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Strength

If high impact loads are transmitted through the spindle shaft, then blade cutting performance is maintained, but shaft and motor damage can occur

Engineering Contradiction:

Improveblade cutting capabilityVSAvoidshaft and motor durability

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent incorporates a magnetic coupling system that inherently limits torque transmission. When impact loads exceed the magnetic coupling's torque capacity, the coupling slips or disengages, cushioning the blow before it reaches the motor and protecting the system from damage

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The rigid mechanical power transmission system is replaced with a magnetic coupling system that provides inherent torque limiting. This substitution allows the system to maintain cutting performance under normal loads while automatically protecting against damage from high impact loads

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 magnetic coupling system provides a leak-free environment, reduces maintenance costs, and prevents shaft and motor damage from high impact loads, while optimizing space and eliminating the need for case drain lines, enhancing the reliability and efficiency of blade rotation systems.

Implementation Method 1

one or more first permanent magnets are configured to magnetically engage the one or more second permanent magnets so that rotation of the drive shaft by the hydraulic gear motor translates into rotation of the spindle shaft

Methodology Applied

Scientific EffectMagnetic coupling: Magnetism

Implementation Method 2

provides a torque limiter function corresponding to magnetic attraction of the permanent magnets that make up the magnetic coupling

Methodology Applied

Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentUS11399460B1Blade rotation system

Publication Date: 2022.08.02 PARKER INTANGIBLES LLC

AI summary

A blade rotation system including an hydraulic gear motor and a spindle shaft. The hydraulic gear motor has a drive shaft, and the drive shaft is configured with one or more first permanent magnets coupled thereto. The spindle shaft is adapted for connection to a blade, and the spindle shaft is configured with one or more second permanent magnets coupled thereto. The one or more first permanent magnets are configured to magnetically engage the one or more second permanent magnets so that rotation of the drive shaft by the hydraulic gear motor translates into rotation of the spindle shaft to impart motion to the blade.