Embedded Outer Rotor Motor Direct-Drive Lawnmower Wheel

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Solution Overview

Problem

Existing mower driving wheel structures have complex designs due to externally located drive motors, which compromise transmission precision and reliability, and often feature high rotation speed but low movement inertia.

Innovation Solution

An embedded-outer rotor motor direct driven mower driving wheel design places the outer rotor motor inside the driving wheel, directly driving the mower wheel, enhancing transmission precision and reliability while improving walking stability and utilizing space more efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the drive motor is located outside the wheel and mounted on the mower, then the motor can be easily installed and maintained, but the structure becomes relatively complex and occupies space that impacts the setting of other mechanisms

Engineering Contradiction:
Improvemotor installation and maintenanceVSAvoidoverall structure complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the drive motor with the driving wheel by embedding the outer rotor motor directly into the wheel structure. The wheel side cover I, wheel side cover II, and wheel body are assembled to form a housing that contains the motor, integrating two previously separate components (motor and wheel) into a single unified structure. This eliminates the need for separate motor mounting positions and reduces overall structural complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The outer rotor motor is nested within the driving wheel structure. The stator portion is fixed to the wheel side cover I, the outer rotor portion is fixed to the wheel side cover II, and the wheel body is positioned between them, creating a nested arrangement where the motor components are housed within the wheel assembly. This nesting approach optimizes space utilization and simplifies the overall mower structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of operation

If the drive motor is located outside the wheel, then the motor can be independently accessed, but it occupies certain space that impacts the setting of other mechanisms on the mower

Engineering Contradiction:
Improvemotor accessibilityVSAvoidspace occupied by motor
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The motor and wheel are merged into a single integrated component, eliminating the need for separate motor mounting space on the mower body. The motor occupies only the space within the wheel assembly itself, significantly reducing the overall space requirement and allowing better accommodation of other mechanisms on the mower.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor is repositioned from an external mounting location to an internal position within the wheel structure. This dimensional reorganization places the motor in the radial dimension of the wheel rather than requiring axial or lateral space on the mower body, optimizing the three-dimensional space utilization of the mower system.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Speed

If common inner rotor motors are used, then the motor structure is compact, but they have high rotation speed but relatively low movement inertia

Engineering Contradiction:
Improverotation speedVSAvoidmovement inertia
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The patent inverts the conventional motor configuration by using an outer rotor motor instead of an inner rotor motor. In this inverted arrangement, the rotor is on the outside and the stator is on the inside, which reverses the typical inertia characteristics. The outer rotor configuration with the wheel body positioned between the stator and rotor increases the moment of inertia, providing better movement stability while maintaining the ability to achieve high rotation speeds.

Inventive Principle:
Principle #13The other way round (Inversion)

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 design improves transmission precision and reliability, enhances walking stability, and optimizes mower internal space, resulting in a more robust and less prone to damage driving wheel structure.

Implementation Method 1

an outer rotor motor is mounted in the cavity, an outer rotor portion of the outer rotor motor is fixedly arranged relative to the driving wheel main body

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3152998B1Embedded outer rotor electric motor direct-drive lawnmower drive wheel, and lawnmower
Publication Date: 2019.09.11 ZHEJIANG YAT ELECTRICAL APPLIANCE CO LTD
  • EP3152998B1 patent drawingFigure 1
  • EP3152998B1 patent drawingFigure 2
  • EP3152998B1 patent drawingFigure 3

AI summary

The present invention provides an embedded-outer rotor motor direct driven mower driving wheel and a mower. The embedded-outer rotor motor direct driven mower driving wheel comprises a driving wheel main body formed by the assembling of a wheel side cover I, a wheel side cover II, and a wheel body sandwiched between the wheel side cover I and the wheel side cover II, the wheel side cover I, the wheel side cover II and the wheel body are enclosed to define a cavity, an outer rotor motor is mounted in the cavity, an outer rotor portion of the outer rotor motor is fixedly arranged relative to the driving wheel main body, an internal stator portion of the outer rotor motor is provided with a fixed shaft penetrating through the wheel side cover I and extending out of the driving wheel main body, and the wheel side cover I is provided with a shaft hole I allowing the fixed shaft to penetrate through. The present invention arranges the outer rotor motor inside the driving wheel and directly drives the mower driving wheel through the outer rotor motor, thus, transmission precision and reliability are good, and the inner space of the mower is more reasonable.