Integrated Gearbox Switching Unit With External Rotor Actuation

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Solution Overview

Problem

Existing motor vehicle transmissions with electric motors and gearboxes have high dimensions, weight, and cost, and lack flexibility in application due to separate units, leading to inefficiencies and reduced power transfer efficiency due to electromagnetic coupling issues.

Innovation Solution

A motor vehicle transmission design featuring an outer rotor motor with induction units, a gear device that converts torque, and a high degree of integration with a U-shaped cut surface configuration, including a planetary gear system and electronic units for efficient energy transfer and reduced imbalance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If electric motors with high torque and low speed are used, then power output is maintained, but the motors become larger, heavier, and more expensive

Engineering Contradiction:
Improvepower outputVSAvoidmotor weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent merges the electric motor and gearbox into a single integrated unit where the motor rotor is directly coupled to the planetary gear system. This integration eliminates separate mounting structures and reduces overall weight while maintaining the power output by optimizing the shared mechanical components between motor and transmission system

Inventive Principle:
Principle #5Merging (Combining)

2Power

If electric motors with high torque and low speed are used, then power output is maintained, but the motors become larger and more expensive

Engineering Contradiction:
Improvepower outputVSAvoidsystem complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent combines the electric motor and gearbox into one integrated unit with shared components. The motor rotor serves as part of the planetary gear system, eliminating the need for separate mounting flanges, bearings, and coupling mechanisms. This reduces device complexity and cost while maintaining power output capability

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated design allows components to serve multiple functions. The motor rotor structure simultaneously acts as a gear element in the planetary system, and the housing serves both as motor enclosure and gearbox casing, reducing the number of parts needed and simplifying manufacturing

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

3Ease of manufacture

If separate electric motor and gearbox units are arranged in a row, then modular assembly is achieved, but the actuator becomes large and heavy with limited flexibility

Engineering Contradiction:
Improvemodular assemblyVSAvoidactuator volume
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent integrates the electric motor and gearbox into a single compact unit where the motor rotor is directly coupled to the planetary gear system. This eliminates the need for separate mounting flanges and coupling mechanisms, significantly reducing the overall actuator volume while maintaining ease of assembly through standardized interfaces

Inventive Principle:
Principle #5Merging (Combining)

4Length of stationary object

If the air gap between stator and cam disc is increased, then electromagnetic coupling decreases, but efficiency and power output are reduced

Engineering Contradiction:
Improveair gap widthVSAvoidelectromagnetic coupling efficiency
Core Design Contradiction:
Length of stationary objectVSLoss of energy

Solution Approach 1:

The patent replaces the cam disc mechanism with a planetary gear system that uses magnetic coupling throughout. This eliminates the need for mechanical contact and allows for optimized magnetic field coupling with minimal air gap, improving electromagnetic efficiency while maintaining the required mechanical output

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 design achieves high efficiency, energy efficiency, and installation space efficiency by integrating the gearbox and actuating motor, reducing weight and cost while maintaining high power transfer efficiency and flexibility.

Implementation Method 1

at least one induction unit which is provided for supplying energy to the actuating motor and which has at least one primary coil and at least one secondary coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

The drive comprises a rotor and a stator with coils arranged in a ring around the rotor, which are designed to generate a controllably variable magnetic field when a suitable current is applied

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Data Source

PatentEP3682146B1Motor vehicle gearbox with switching unit activated by electric motor
Publication Date: 2021.08.04 MERCEDES BENZ GROUP AG
  • EP3682146B1 patent drawingFigure 1
  • EP3682146B1 patent drawingFigure 2

AI summary

The invention relates to a motor vehicle gearbox (10) having at least one housing (12), having at least one switching unit (14) which has a first coupling element (16) and a second coupling element (18) which can be connected in a rotationally fixed fashion to the first coupling element (16), having at least one activation motor (20) which is embodied as an external rotor motor and which is provided for activating the switching unit (14), and which activation motor (20) has a rotor (22) and a stator (24), having at least one induction unit (26) which is provided for supplying energy to the activation motor (20) and has at least one primary coil (28) and at least one secondary coil (30), having at least one gearbox device (32) which is provided for converting a torque, acting in a circumferential direction, of the actuation motor (20) into an axially acting activation force, and which has a gearbox unit (34) with a first ring gear, wherein the first coupling element (16) and the stator (24) are connected in a permanently rotationally fixed fashion by means of a first plate unit (48), wherein the stator (24) is connected in a permanently rotationally fixed fashion to at least one gearbox element of the gearbox unit (34) by means of a second plate unit (50), and the stator (24) is arranged axially between the first plate unit (48) and the second plate unit (50).