Three-Axis Gimbal Cable Routing Through Hollow Motor Shafts

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Solution Overview

Problem

Conventional gimbals face issues with wire winding and scraping due to flexible printed circuit boards, leading to reduced service life and limited connection buses and rotation angles, especially in multi-axis systems, which restrict high-speed signal transmission and increase thickness.

Innovation Solution

The three-axis gimbal design incorporates conductive wires that pass through hollow motor shafts and are arranged within the support arms, using coaxial wires and board-to-board connectors to prevent wire winding and scraping, enabling compact and reliable high-speed data transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If flexible printed circuit board is wound on motor shaft surface, then connection between motor and control part is achieved, but winding space increases and motor thickness increases

Engineering Contradiction:
Improveconnection reliabilityVSAvoidmotor thickness
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The flexible printed circuit board is extracted from the motor shaft surface and routed through the hollow interior of the motor shaft. This removes the winding space requirement from the motor exterior, reducing motor thickness while maintaining reliable electrical connection between the rotating body and control part.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The flexible printed circuit board is nested within the hollow motor shaft, utilizing the internal space of the motor structure. This nesting approach eliminates the need for external winding space, thereby reducing motor thickness while preserving connection functionality.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Reliability

If flexible printed circuit board is used for signal transmission, then connection is established, but transmission rate is limited due to board process

Engineering Contradiction:
Improveconnection reliabilityVSAvoidsignal transmission rate
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The patent changes the physical form parameter of the connection medium from a planar flexible printed circuit board to a three-dimensional cable assembly that can be routed through the motor shaft. This parameter change enables higher signal transmission rates while maintaining reliable electrical connections throughout the gimbal system.

Inventive Principle:
Principle #35Parameter changes

3Volume of moving object

If connection bus is arranged directly from outer part to control part without passing through motor, then motor thickness is reduced, but number of connection buses and rotation angles are limited causing winding or scraping

Engineering Contradiction:
Improvemotor thicknessVSAvoidservice life
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The hollow motor shaft serves as an intermediary structure that accommodates and protects the flexible printed circuit board during rotation. This intermediary approach allows the connection bus to pass through the motor shaft interior rather than being exposed externally, preventing winding and scraping while maintaining adequate rotation angles and extending service life.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If flexible printed circuit board is exposed outside support arm and coupled to camera, then connection is simplified, but wire winding and scraping occur reducing service life

Engineering Contradiction:
Improveconnection easeVSAvoidservice life
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The flexible printed circuit board is extracted from the external support arm environment and routed through the protected interior of the hollow motor shaft. This extraction removes the board from the harmful external rotation environment, preventing winding and scraping while maintaining connection functionality to the camera and control systems.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP3492391B1Three-axis pan-tilt base, and three-axis pan-tilt camera device
Publication Date: 2021.04.28 SZ DJI OSMO TECH CO LTD
  • EP3492391B1 patent drawingFigure 1~2
  • EP3492391B1 patent drawingFigure 3~4

AI summary

A three-axis gimbal and three-axis gimbal photographing apparatus are provided. A the first electromechanical coupling apparatus (12) of the three-axis gimbal includes a first hollow motor shaft (121). The first hollow motor shaft (121) has a first accommodation cavity (120). A second electromechanical coupling apparatus (22) includes a second hollow motor shaft (221). The second hollow motor shaft (221) has a second accommodation cavity 220). A pitch axis arm (21) includes a pitch axis accommodation cavity (210), A roll axis component (1) includes a first conductive wire (13) configured in the first accommodation cavity (120) and the roll axis arm accommodation cavity (110). A pitch axis component (2) includes a second conductive wire (23) configured in the second accommodation cavity (220) and the pitch axis arm accommodation cavity (210). The first conductive wire (13) is connected to the second conductive wire (23).