Rotor Shaft Support Structure With Single-Bearing Vibration Cushioning

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Solution Overview

Problem

Existing rotating electric machines face complications due to the use of ball bearings at both ends of the rotor shaft, leading to increased friction loss and reduced durability, particularly when the rotor shaft is connected to a transmission.

Innovation Solution

The rotor shaft is supported at one end by a double row angular contact ball bearing and connected to the transmission via a spigot joint structure, with elastic members and grease to cushion vibrations and prevent wear, while the other end is supported by the transmission's ball bearing, eliminating the need for additional bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ball bearings are disposed at both ends of the rotor shaft, then the rotor shaft is stably supported, but the overall configuration becomes complicated and friction loss increases

Engineering Contradiction:
Improvesupport stabilityVSAvoidconfiguration complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent removes one ball bearing from the system, keeping only a single ball bearing at one end of the rotor shaft. The other end is connected to the transmission housing directly without a bearing, thereby simplifying the configuration while maintaining adequate support functionality through the transmission housing connection.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If ball bearings are disposed at both ends of the rotor shaft, then the rotor shaft is stably supported, but friction loss increases due to both bearings

Engineering Contradiction:
Improvesupport stabilityVSAvoidfriction loss
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent eliminates one ball bearing from the system, retaining only a single ball bearing at one end of the rotor shaft. This reduction in bearing quantity directly decreases the friction loss while the transmission housing connection at the other end provides sufficient support stability.

Inventive Principle:
Principle #2Taking out (Extraction)

3Loss of energy

If only one end of the rotor shaft is supported by a ball bearing and the other end is connected by spline or spigot, then friction loss is reduced, but vibration transmitted to the bearing reduces durability

Engineering Contradiction:
Improvefriction lossVSAvoidbearing durability
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent introduces a damping element (such as a rubber isolator or vibration absorber) between the rotor shaft and the transmission housing connection. This cushioning element absorbs vibrations before they can be transmitted to the bearing, thereby protecting the bearing from vibration-induced damage and extending its durability while maintaining the single-bearing configuration that reduces friction loss.

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

4Device complexity

If only one end of the rotor shaft is supported by a ball bearing, then the configuration is simplified and friction loss is reduced, but the structure becomes less stable

Engineering Contradiction:
Improveconfiguration simplicityVSAvoidsupport stability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent merges the support function of the second bearing with the transmission housing structure. The transmission housing itself serves as the support structure for the rotor shaft at the second end, eliminating the need for a separate bearing while maintaining support stability. This integration achieves configuration simplification without sacrificing structural stability.

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

This configuration simplifies the machine's design, reduces friction, enhances durability, and prevents wear, thereby improving the overall performance and reducing manufacturing costs.

Implementation Method 1

a vibration cushioning member for cushioning vibration generated between the rotor shaft and the rotation shaft of the power transmission device

Methodology Applied
Scientific EffectVibration cushioning: Damping

Implementation Method 2

a vibration cushioning member for cushioning vibration generated between the rotor shaft and the rotation shaft of the power transmission device

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 3

a lubricating agent for preventing adhesion between the rotor shaft and the rotation shaft of the power transmission device

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP4068587B1Rotary electric machine
Publication Date: 2025.11.12 NISSAN MOTOR CO LTD
  • EP4068587B1 patent drawingFigure 1
  • EP4068587B1 patent drawingFigure 2
  • EP4068587B1 patent drawingFigure 3

AI summary

A rotating electric machine including a rotor and a stator in a housing, the rotor having a rotor shaft connected to a power transmission shaft of a power transmission device, is providing, a bearing is provided in the housing, one end portion of the rotor shaft is supported by the bearing, the other end portion of the rotor shaft is supported by the power transmission shaft with a spigot joint structure fitted to the power transmission shaft, and an elastic member is provided between the bearing and the rotor shaft.