Powertrain Shaft Coupling With Wave Spring for Axial Impact Damping

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Solution Overview

Problem

The assembly complexity and cost of powertrains are high due to the fastening of motor output shafts, leading to increased wear and noise when the shafts collide during axial impacts.

Innovation Solution

A powertrain design with an elastic component between the output and input shafts, allowing axial movement and using limiting platforms and coupling surfaces for transmission, with a waveform spring providing axial preload and adapting to different operational states.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor output shaft is completely fastened to eliminate axial movement, then the transmission connection is stable, but the assembly complexity and manufacturing requirements increase

Engineering Contradiction:
Improvetransmission connection stabilityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by allowing the motor output shaft to have controlled axial movement capability through the elastic component (waveform spring) rather than completely fastening it. The waveform spring enables the output shaft to dynamically adapt to axial impacts while maintaining transmission connection, eliminating the need for complex fastening structures and reducing assembly complexity.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the motor output shaft is completely fastened, then the transmission connection is stable, but the manufacturing requirements and design complexity of housing increase

Engineering Contradiction:
Improvetransmission connection stabilityVSAvoidassembly requirement
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The waveform spring provides dynamic compliance that absorbs axial movements, eliminating the need for high-precision manufacturing of housing and fastening structures. The elastic component compensates for manufacturing tolerances and reduces the stringency of assembly requirements.

Inventive Principle:
Principle #15Dynamics

3Stability of the object's composition

If the motor output shaft is rigidly fastened, then structural stability is maintained, but wear and noise increase during axial impacts

Engineering Contradiction:
Improvestructural stabilityVSAvoidwear and noise
Core Design Contradiction:
Stability of the object's compositionVSObject-generated harmful factors

Solution Approach 1:

The waveform spring acts as a pre-installed cushioning element between the motor output shaft and the load. During axial impacts, the elastic component absorbs the impact energy through deformation, preventing direct collision between rigid components. This beforehand cushioning reduces wear and noise while maintaining structural stability.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The elastic component serves as an intermediary element between the motor output shaft and the driven load. This mediator absorbs axial movements and impacts, preventing direct contact and friction between rigid surfaces, thereby reducing wear and noise generation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Reduces assembly requirements, minimizes wear and noise, and enhances stability by allowing the elastic component to adapt to axial impacts, thus improving the powertrain's operational efficiency and durability.

Implementation Method 1

an elastic component is disposed between the output shaft and the input shaft, allowing the motor to have an axial movement during running

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

with a waveform spring providing axial preload and adapting to different operational states

Methodology Applied
Scientific EffectWaveform spring: Spring

Data Source

PatentEP4403789B1Power assembly and automobile
Publication Date: 2025.09.03 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4403789B1 patent drawingFigure 1~2
  • EP4403789B1 patent drawingFigure 3~4
  • EP4403789B1 patent drawingFigure 5a~5b

AI summary

A powertrain includes a motor, a reducer, and an elastic component. The reducer includes an input shaft, the motor includes an output shaft, the input shaft is coaxially coupled to the output shaft, a coupling end of the input shaft includes a first limiting platform and a first coupling surface, and a coupling end of the output shaft includes a second limiting platform and a second coupling surface. The first coupling surface and the second coupling surface are disposed opposite to each other along a radial direction of the input shaft, and the first coupling surface is in contact with the second coupling surface, so that the output shaft is in transmission connection with the input shaft. The first limiting platform and the second limiting platform are disposed opposite to each other along an axial direction of the input shaft. The elastic component is fastened between the first limiting platform and the second limiting platform. The first limiting platform and the second limiting platform are disposed opposite to each other along the axial direction of the input shaft, and the elastic component is disposed between the first limiting platform and the second limiting platform. The elastic component allows the motor to move axially in an operation process. Compared with a manner in which inner and outer rings of a bearing of a fixed motor are completely fastened, this reduces an assembly requirement of the motor and a design requirement of a housing