Variable-Pitch Motor Unit Layout for Compact Multicopters

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Solution Overview

Problem

Existing multicopter motor units tend to increase in size in the axial direction due to the placement of variable pitch mechanism components above the electric motor, leading to larger dimensions and potential vibration issues.

Innovation Solution

The motor unit incorporates a pitch angle changing mechanism with a displaceable displacement member located inside the stator, including a rotating member, support member, ball joint, and moving member, which rotates with the rotor and blade, allowing for cyclic and collective pitch control while minimizing axial size by positioning components within the stator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the variable pitch mechanism components (pitch plate, pitch plate boss, pitch lever, servomotor) are located above the electric motor, then the pitch angle control function is achieved, but the axial size of the motor unit increases

Engineering Contradiction:

Improvepitch angle controlVSAvoidaxial size

Core Design Contradiction:

Ease of operationVSLength of moving object

Solution Approach 1:

The pitch angle changing mechanism is nested inside the stator of the electric motor. The displacement member is positioned within the stator's internal space, and the pitch control mechanism is integrated into the motor structure, allowing the pitch control function to be achieved without increasing the axial size of the motor unit.

Inventive Principle:

Principle #7Nested doll (Nesting)

Solution Approach 2:

Instead of arranging the pitch control components in the axial direction (above the motor), the invention repositions them in the radial direction (inside the stator). This dimensional change allows the pitch control mechanism to occupy space that would otherwise be unused, thereby reducing the axial length of the motor unit.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Length of moving object

If the displacement member is positioned inside the stator, then the axial size is reduced, but the space for component arrangement becomes more constrained

Engineering Contradiction:

Improveaxial sizeVSAvoidcomponent arrangement

Core Design Contradiction:

Length of moving objectVSDevice complexity

Solution Approach 1:

The pitch angle changing mechanism is divided into functional components (displacement member, pitch control mechanism) that are independently arranged within the stator. This segmentation allows each component to be optimally positioned in the constrained space, facilitating assembly and maintenance while achieving compact dimensions.

Inventive Principle:

Principle #1Segmentation

3Length of moving object

If the pitch angle changing mechanism is integrated into the motor structure, then the axial size is reduced, but the potential for vibration increases

Engineering Contradiction:

Improveaxial sizeVSAvoidvibration

Core Design Contradiction:

Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The pitch angle changing mechanism is merged with the motor structure, where the displacement member is integrated into the stator assembly. This integration reduces the number of separate components and connection points, thereby minimizing potential sources of vibration and improving overall structural rigidity.

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11975829B2Motor unit and aircraft

Publication Date: 2024.05.07 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A motor unit includes a motor and a pitch angle changing mechanism. The motor generates power for rotating a blade. The pitch angle changing mechanism changes a pitch angle of the blade. The motor includes a stator and a rotor. The rotor is located outside of the stator and the blade is coupled to the rotor. The pitch angle changing mechanism includes one displaceable displacement member. A part of the displacement member is located inside of the stator.