Cross-Plane EV Gearbox Layout for Twin-Motor Torque Packaging

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Solution Overview

Problem

Existing drivetrain and gearbox designs for electric vehicles are cumbersome and occupy significant space within the vehicle, leading to increased weight and cost, particularly when handling torque from multiple electric motors in a side-by-side configuration.

Innovation Solution

A compact gearbox design that utilizes a central plane to separate the drivetrain into two half-spaces, allowing for a spatial shift of torque flow through cross-plane intermediate elements, thereby reducing the overall width and length of the gearbox while maintaining high torque handling capability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a side-by-side twin motor gearbox configuration is used to handle torque from multiple electric motors, then the torque handling capability is improved, but the overall width and volume of the gearbox increases significantly

Engineering Contradiction:
Improvetorque handling capabilityVSAvoidgearbox volume
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The patent applies dimensionality change by shifting the torque flow path from a lateral arrangement to a longitudinal arrangement through the gearbox. Instead of having separate driving lines positioned side-by-side that increase width, the invention uses cross-plane intermediate elements to transfer torque across the central plane, allowing both motors to feed into a more compact configuration that reduces overall gearbox volume while maintaining the capability to handle torque from multiple electric motors

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Power

If separate driving lines are provided for each motor in a side-by-side configuration, then the torque transfer from each motor is optimized, but the transverse dimension and weight of the gearbox increases

Engineering Contradiction:
Improvetorque transfer efficiencyVSAvoidgearbox weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent merges the two separate driving lines by introducing a central plane and cross-plane intermediate elements that allow torque from both motors to be combined and transmitted through shared components. This merging approach maintains optimized torque transfer from each motor while reducing the need for completely separate transmission paths, thereby reducing the transverse dimension and overall weight of the gearbox

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If long transversal shafts are used to support gears in separated half-spaces, then the gear support and torque transmission is ensured, but the manufacturing cost and overall dimensions increase

Engineering Contradiction:
Improvegear support reliabilityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent segments the gearbox into two half-spaces separated by a central plane, with each motor's driving line primarily serving its respective half-space. The segmentation is achieved through the central plane and cross-plane intermediate elements that allow compact gear arrangements in each half-space without requiring long transversal shafts to span the entire width, thereby reducing manufacturing complexity and cost while maintaining reliable gear support

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4336067B1A gearbox/drivetrain for a vehicle
Publication Date: 2025.05.21 RIMAC TECH D O O
  • EP4336067B1 patent drawingFigure 1
  • EP4336067B1 patent drawingFigure 2
  • EP4336067B1 patent drawingFigure 3

AI summary

A gearbox/drivetrain comprises a frame defining a central plane respectively opposite half-spaces, and two driving lines housed in such half-spaces; the driving lines comprise respective torque input elements and torque output elements, and they further comprise at least a cross-plane intermediate element adapted to transmit torque coming from the first or from the second torque input towards the first or to the second torque output and across said central plane.