Offset-Shaft Electromechanical Brake Layout for Compact Wheel Packaging

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Solution Overview

Problem

Existing electro-mechanical brake systems face challenges in miniaturization while maintaining reliable braking performance, particularly in adapting to limited wheel space in vehicles.

Innovation Solution

The electro-mechanical brake apparatus incorporates a planetary gear set reducer with an offset transmission shaft, integrating the brake motor and reducer to reduce axial size and overall volume, thereby achieving miniaturization without compromising braking reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the brake motor and reducer are integrated with an offset transmission shaft, then the axial size and overall volume are reduced, but the structural complexity increases

Engineering Contradiction:
Improveoverall volumeVSAvoidstructural complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The brake motor and reducer are merged into an integrated structure where the rotor of the brake motor serves as the transmission shaft of the reducer. The stator, rotor, and planetary gear set are combined in a single assembly, reducing the need for separate components and connections, thereby reducing overall volume while managing structural complexity through functional integration.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The planetary gear set is nested within the rotor structure, with the transmission shaft passing through the rotor and connecting to the planet gear. This nesting arrangement allows the reducer components to be housed within the motor assembly, significantly reducing the axial size and overall volume of the electro-mechanical brake system.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Length of moving object

If the planetary gear set and rotor are combined, then the axial size is reduced, but the manufacturing precision requirements increase

Engineering Contradiction:
Improveaxial sizeVSAvoidmanufacturing precision
Core Design Contradiction:
Length of moving objectVSManufacturing precision

Solution Approach 1:

The rotor and planetary gear set are merged into a single integrated assembly, eliminating the need for separate mounting interfaces and reducing the number of precision mating surfaces. The transmission shaft is directly formed as part of the rotor structure, reducing alignment requirements and manufacturing precision demands while achieving compact axial dimensions.

Inventive Principle:
Principle #5Merging (Combining)

3Volume of moving object

If the transmission shaft axis is offset from the rotor axis, then the miniaturization is achieved, but the reliability requirements increase

Engineering Contradiction:
Improvesystem volumeVSAvoidreliability
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The transmission shaft is deliberately offset from the rotor axis to create an asymmetric configuration that enables compact packaging. The planet gear is positioned at this offset location, and the asymmetric arrangement is designed to distribute loads appropriately, maintaining reliability while achieving miniaturization of the overall system volume.

Inventive Principle:
Principle #4Asymmetry

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 enables a compact electro-mechanical brake system that effectively adapts to limited wheel space, ensuring reliable braking performance while reducing the system's volume.

Implementation Method 1

a brake motor, where the brake motor includes a rotor and a stator; and a reducer, where the reducer includes a transmission shaft and a planetary gear set. An axis of the transmission shaft is offset to an axis of the rotor along a radial direction of the brake motor, the rotor is configured to drive the transmission shaft to rotate around the axis of the rotor

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 2

the transmission shaft is configured to drive, through a planet gear of the planetary gear set, a sun gear of the planetary gear set to rotate

Methodology Applied
Scientific EffectGear transmission: Gear

Implementation Method 3

the electro-mechanical brake apparatus is configured to be fastened to a brake caliper and drive a friction plate to brake a wheel

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4570605A1Electro-mechanical brake apparatus with offset transmission shaft of reducer, system, and vehicle
Publication Date: 2025.06.18 HUAWEI DIGITAL POWER TECH CO LTD
  • EP4570605A1 patent drawingFigure 1~2
  • EP4570605A1 patent drawingFigure 3
  • EP4570605A1 patent drawingFigure 4

AI summary

This application provides an electro-mechanical brake apparatus with an offset transmission shaft of a reducer, a system, and a vehicle. The electro-mechanical brake apparatus is configured to be fastened to a brake caliper and drive a friction plate to brake a wheel. The electro-mechanical brake apparatus includes a brake motor and the reducer. The brake motor includes a rotor and a stator. The reducer includes the transmission shaft and a planetary gear set. An axis of the transmission shaft is offset to an axis of the rotor along a radial direction of the brake motor, the rotor is configured to drive the transmission shaft to rotate around the axis of the rotor, the transmission shaft is configured to drive, through a planet gear of the planetary gear set, a sun gear of the planetary gear set to rotate, and the sun gear is configured to drive the friction plate through a feed mechanism. In this application, the electro-mechanical brake apparatus uses the rotor to form a structure similar to a planet carrier in the planetary gear set of the reducer, to implement integral integration of the brake motor and the reducer. This reduces an axial size of the electro-mechanical brake apparatus, and implements miniaturization of the electro-mechanical brake apparatus on a premise of ensuring reliable braking of the electro-mechanical brake apparatus.