Hub Motor Coupling Shaft Layout for Easier Power Cable Assembly

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Solution Overview

Problem

Existing hub motor assemblies face challenges in assembling power cables efficiently and preventing cable damage due to excessive bending angles, which increases the risk of wear and tear.

Innovation Solution

The hub motor assembly incorporates a coupling shaft with wire holes to separate and fix core wires to the circuit board, facilitating assembly and reducing the risk of cable damage by minimizing excessive bending angles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the motor-generator cable is routed through a longitudinal groove in the motor-generator shaft, then the cable routing path is simplified, but the cable must bend at nearly 90 degrees which increases wear risk and makes assembly difficult

Engineering Contradiction:
Improvecable routing complexityVSAvoidcable durability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The coupling shaft is divided into multiple functional sections: an outer shaft portion with wire holes for cable routing, an inner shaft portion that creates a protective cavity, and a wing portion for motor mounting. This segmentation allows the cable to pass through multiple small wire holes rather than making a single 90-degree bend, distributing the bending stress and reducing wear risk while maintaining routing simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The inner shaft portion is nested within the outer shaft portion, creating a protective cavity that houses the cable. The cable passes through the inner shaft portion's cavity and is secured by adhesive injected through the outer shaft portion's wire holes. This nested structure protects the cable from external damage and prevents excessive bending while maintaining a compact design

Inventive Principle:
Principle #7Nested doll (Nesting)

2Ease of manufacture

If the cable is routed through a simple longitudinal groove, then the assembly process is simpler, but the cable assembly becomes difficult and time-consuming

Engineering Contradiction:
Improvecable routing easeVSAvoidcable assembly efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The coupling shaft is pre-configured with wire holes positioned at optimal locations before cable installation. The inner shaft portion is already in place creating the protective cavity. This preliminary preparation allows the cable to be quickly inserted and secured without complex routing operations, significantly improving assembly efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Adhesive serves as an intermediary substance that is injected through the wire holes to secure the cable within the protective cavity. This intermediary mechanism simplifies the cable fixation process, making it quick and reliable without requiring complex mechanical fastening operations

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4513722A1Hub motor assembly
Publication Date: 2025.02.26 J D COMPONENTS CO LTD
  • EP4513722A1 patent drawingFigure 1
  • EP4513722A1 patent drawingFigure 2
  • EP4513722A1 patent drawingFigure 3

AI summary

A hub motor assembly (10) includes a hub motor (20), a coupling shaft (30), and a power cable (40). The hub motor (20) has a hub shell (21), a motor (24) disposed in the hub shell (21), and a circuit board (25) fixed to the motor (24). The coupling shaft (30) is inserted in a first shaft hole (212) of the hub shell (21) and fixed to the motor (24) and provide with a second shaft hole (32), a notch (35) radially connected to the second shaft hole (32), and an inner annular portion (33) radially protruding from the periphery wall of the second shaft hole (32) and having multiple wire holes (34). The power cable (40) has multiple core wires (43) inserted into the second shaft hole (32) through the notch (35) and inserted into the hub shell (21) through the wire holes (34) to be electrically connected to the circuit board (25). As such, the hub motor assembly (10) of the present invention can achieve an effect of convenient assembly of the power cable (40).