Wheel Hub Motor Generator for Vehicle Power Assist

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Solution Overview

Problem

Existing vehicle power assist systems require complex control to stabilize regenerative power during braking and result in increased vehicle weight and reduced fuel economy due to complex structures and additional battery weight, while also increasing running resistance and parts count.

Innovation Solution

A vehicle power assist system with a motor generator mounted to a wheel support bearing assembly, capable of generating electrical power from driven wheel rotations and receiving electrical power, eliminating the need for a clutch and mechanical power distributing mechanisms, and using a medium voltage battery for regenerative power storage and supply, allowing for direct drive and simplified structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a motor generator is mechanically connected to driven wheels through a clutch and mechanical power distributing mechanism, then power assist and regenerative braking functions are achieved, but the device complexity and vehicle weight increase

Engineering Contradiction:
Improvepower assist functionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the clutch and mechanical power distributing mechanism from the system. The motor generator is directly mounted to the wheel support bearing assembly, removing unnecessary mechanical transmission components while retaining the core power assist and regenerative braking functions.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent merges the motor generator mounting directly to the wheel support bearing assembly, combining previously separate components (motor generator, bearing assembly) into an integrated unit. This eliminates the need for intermediate mechanical power transmission mechanisms.

Inventive Principle:
Principle #5Merging (Combining)

2Quantity of substance

If additional battery and power distribution components are added, then regenerative power storage capability is improved, but the vehicle weight increases

Engineering Contradiction:
Improveregenerative power storageVSAvoidvehicle weight
Core Design Contradiction:
Quantity of substanceVSWeight of moving object

Solution Approach 1:

The patent makes the existing battery serve multiple functions - it continues to power vehicle electronics and now also stores regenerative power from the motor generator. This eliminates the need for a separate auxiliary battery, reducing overall vehicle weight while maintaining full regenerative power storage capability.

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

3Adaptability or versatility

If a clutch is used to disconnect the motor generator from driven wheels, then mechanical unconnection is achieved, but the device complexity increases

Engineering Contradiction:
Improvemechanical disconnection capabilityVSAvoidparts count
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent removes the clutch from the system entirely. The motor generator is directly mounted to the wheel support bearing assembly, eliminating the need for mechanical disconnection devices while maintaining the ability to engage and disengage power transmission through electrical control of the motor generator itself.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution improves traveling and braking performance, reduces vehicle weight, and enhances fuel efficiency by minimizing the increase in vehicle weight and parts count, while providing a reliable and efficient power assist system.

Implementation Method 1

a motor generator 8 configured to be capable of generating an electrical power from rotations of the driven wheel 4

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a power storage unit configured to store a regenerative power generated by the motor generator 8

Methodology Applied
Scientific EffectElectrochemical energy storage: Battery (electricity)

Data Source

PatentEP3517343B1Vehicle power assist system
Publication Date: 2021.07.28 NTN CORP
  • EP3517343B1 patent drawingFigure 1
  • EP3517343B1 patent drawingFigure 2
  • EP3517343B1 patent drawingFigure 3

AI summary

A vehicle power assist system can be applied to a vehicle with a driven wheel (4) that is mechanically unconnected to a main drive source (5) such as an internal combustion engine. The driven wheel (4) is supported by a wheel support bearing assembly (31) to which a drive assist, motor generator (8) is mounted. A rotor of the motor generator (8) is directly fixed to a rotational ring of the wheel support bearing assembly (31) without interposition of a speed reducing mechanism or a speed increasing mechanism. The vehicle power assist system includes a power storage unit (19) configured to store a regenerative power generated by the motor generator (8) and to supply the stored power to the motor generator (8).