Coaxial Electric Drive Assembly Layout for Compact EV Torque Reduction

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Solution Overview

Problem

Existing vehicle electric drive assemblies face challenges with large motor volume and high manufacturing costs due to the need for high torque and speed, and existing reducers do not fully realize torque and speed reduction functions, leading to inefficiencies and increased costs.

Innovation Solution

A vehicle electric drive assembly with a motor and reducer design where the input and output shafts are coaxially connected through an intermediate shaft, integrated gears for transmission, and a compact housing structure, along with features like oil baffles and coolant grooves for improved efficiency and reduced power loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional separate布置 of motor controller and reducer is used, then assembly and maintenance are convenient, but precision loss occurs due to multiple transmission links

Engineering Contradiction:
Improvetransmission precisionVSAvoidtransmission link complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines the motor controller and reducer into a single integrated drive assembly, eliminating the need for separate transmission links between these components. This merging reduces precision loss while maintaining assembly convenience through modular design.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If motor controller and reducer are integrated, then transmission precision improves, but heat dissipation becomes more difficult due to concentrated heat sources

Engineering Contradiction:
Improvetransmission precisionVSAvoidheat dissipation
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The integrated drive assembly is divided into functionally independent modules (motor controller module, reducer module, heat dissipation module) that can be separately designed and maintained. This segmentation allows concentrated heat sources to be managed through dedicated heat dissipation pathways while maintaining integration benefits.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A heat dissipation module acts as an intermediary between the concentrated heat sources (motor controller and reducer) and the external environment. This intermediary component manages thermal energy transfer, allowing the integrated design to maintain transmission precision while solving heat dissipation challenges.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If multiple transmission links are used for convenience, then assembly is easier, but precision loss increases

Engineering Contradiction:
Improveassembly convenienceVSAvoidtransmission precision
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

By merging the motor controller and reducer into a single integrated unit, the patent eliminates intermediate transmission links that would compromise precision. The integrated design maintains assembly convenience through standardized interfaces and modular construction while ensuring direct power transmission.

Inventive Principle:
Principle #5Merging (Combining)

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 design achieves a compact, low-cost, high-performance drive assembly with reduced volume and weight, enhanced transmission efficiency, and improved NVH performance, while meeting high torque and speed requirements.

Implementation Method 1

after the motor controller and the reducer are integrated, not only is the space occupation reduced, but also the heat dissipation is more difficult, which affects the normal working temperature of the integrated drive assembly

Methodology Applied
Scientific EffectHeat generation: Joule Heating

Data Source

PatentEP4364992B1Electric drive assembly for vehicle and new energy vehicle
Publication Date: 2026.04.08 JING JIN ELECTRIC TECH CO LTD
  • EP4364992B1 patent drawingFigure 1

AI summary

A vehicle electric drive assembly and a new energy vehicle are disclosed. The electric drive assembly comprises a motor (1) and a reducer (2). The motor (1) comprises a motor shaft (3), and the reducer (2) comprises an input shaft (4), an intermediate shaft (5), and an output shaft (6). The input shaft (4) is fixedly connected to the motor shaft (3), the output shaft (6) and the input shaft (4) are coaxially provided, the intermediate shaft (5) is provided parallel to the input shaft (4) and the output shaft (6), and the input shaft (4) drives the output shaft (6) to rotate through the intermediate shaft (5). The electric drive assembly has the advantages of compact structure, simple manufacturing, low cost, high performance, and small space occupation.