Nested Clutch in Integrated Starter Generator for Axial Space Reduction

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Solution Overview

Problem

Conventional hybrid power systems with integrated starter generators (ISGs) face challenges of large axial space occupation, high mass, and manufacturing costs due to the series arrangement of components, which complicates the structure and increases complexity.

Innovation Solution

The proposed hybrid power system incorporates a hollow ring-shaped ISG with a clutch at its center, integrating the rotor and clutch flywheel, and features a stator mounted on the driving motor casing, utilizing circumferentially distributed magnetic poles and tooth-slot iron cores for efficient coil and conductor mounting, along with a cooling system that optimizes the stator's structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the ISG, clutch and driving motor are arranged in series in the direction of the transmission shaft, then the structure is simple, but the axial space occupied is large

Engineering Contradiction:
Improvestructure simplicityVSAvoidaxial space
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The clutch is nested inside the hollow ring-shaped ISG, with the clutch flywheel integrated with the ISG rotor. The clutch housing is positioned within the ISG stator, creating a compact nested arrangement that significantly reduces axial space while maintaining structural simplicity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The clutch flywheel and ISG rotor are merged into a single integrated component, and the clutch housing is combined with the ISG stator structure. This merging of components eliminates the need for separate mounting spaces and reduces overall axial length

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If the ISG, clutch and driving motor are arranged in series, then the structure is simple, but the mass is relatively big

Engineering Contradiction:
Improvestructure simplicityVSAvoidmass
Core Design Contradiction:
Device complexityVSWeight of moving object

Solution Approach 1:

The clutch flywheel and ISG rotor are merged into a single integrated component, eliminating redundant materials and reducing overall mass. The clutch housing is combined with the ISG stator structure, further reducing the total mass of the hybrid power system

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By nesting the clutch inside the ISG, the patent eliminates the need for separate mounting structures and support components, thereby reducing the total mass of the system while maintaining structural integrity

Inventive Principle:
Principle #7Nested doll (Nesting)

3Device complexity

If the ISG, clutch and driving motor are arranged in series, then the structure is simple, but the manufacturing cost is relatively high

Engineering Contradiction:
Improvestructure simplicityVSAvoidmanufacturing cost
Core Design Contradiction:
Device complexityVSEase of manufacture

Solution Approach 1:

The integrated design of the clutch flywheel with the ISG rotor and the clutch housing with the ISG stator reduces the total number of parts that need to be manufactured and assembled, thereby lowering manufacturing costs despite the innovative structural arrangement

Inventive Principle:
Principle #5Merging (Combining)

4Temperature

If the stator is mounted on the driving motor casing with cooling system integration, then cooling efficiency is enhanced, but the structural complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidstructural complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The driving motor casing serves multiple functions: it provides structural support for the stator mounting and simultaneously acts as a cooling system component. This multi-functionality enhances cooling efficiency without significantly increasing structural complexity, as the casing already exists and is repurposed for thermal management

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 reduces axial length, saves space and weight, lowers manufacturing costs, and enhances cooling efficiency, while maintaining functions like engine starting, electricity generation, and power assistance.

Implementation Method 1

the iron core of the stator is provided with a coil winding on the side that faces the rotor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

the iron core of the rotor is provided with a plurality of permanent magnets on the side that faces the stator

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

the iron core of the rotor is provided with a squirrel-cage conductor on the side that faces the stator

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 4

a cooling system that optimizes the stator's structure

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Data Source

PatentEP3493372B1Integrated starter generator and hybrid power system
Publication Date: 2021.10.27 JING JIN ELECTRIC TECH CO LTD
  • EP3493372B1 patent drawingFigure 1~2
  • EP3493372B1 patent drawingFigure 3~4
  • EP3493372B1 patent drawingFigure 5

AI summary

Disclosed is an integrated starter generator (ISG), comprising a stator (4) and a rotor (3). The stator and the rotor are oppositely arranged and are both provided with an annular iron core, a coil winding (121, 131) is arranged on the side, facing the rotor, of the iron core (120, 130) of the stator, a squirrel-cage conductor (123) or a plurality of permanent magnets (133) are arranged on the side, facing the stator, of the iron core (122, 132) of the rotor, and the rotor and the stator are spaced by a certain distance to form an air gap plane. In a hybrid power system installed with the integrated starter generator, a clutch (111) is arranged in an inner ring of the integrated starter generator in a nested manner. By arranging the clutch in the ISG, the axial length of the clutch is completely or partially covered by the axial length of the ISG, and thus the system space is reduced.