Vehicle Drive Layout With Offset Axes to Reduce Axial Length

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Solution Overview

Problem

The axial dimension of vehicle drive devices, which include an input member, a rotary electric machine, a distribution differential gear mechanism, a transmission mechanism, and a disconnection engagement device, tends to increase due to their coaxial arrangement.

Innovation Solution

The distribution differential gear mechanism, rotary electric machine drive gear, and transmission engagement device are disposed on different axes, with the rotary electric machine drive gear positioned on one side and the differential gear mechanism on the other, allowing for a reduced axial dimension.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the distribution differential gear mechanism, first distribution output gear, and disconnection engagement device are disposed coaxially on the first axis, then the power transmission path is simplified and structural alignment is improved, but the axial dimension of the vehicle drive device increases

Engineering Contradiction:
Improvestructural alignmentVSAvoidaxial dimension
Core Design Contradiction:
Device complexityVSLength of moving object

Solution Approach 1:

The patent applies dimensionality change by moving the rotary electric machine and its drive gear from the first axis (coaxial with distribution differential gear mechanism) to a second axis that is offset in the radial direction. This spatial reconfiguration reduces the axial dimension while maintaining functional connectivity through the offset gear engagement between the second distribution output gear and rotary electric machine drive gear

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

2Adaptability or versatility

If the transmission engagement device is disposed on the third axis separate from the first and second axes, then the transmission mechanism can independently switch power transmission states, but the overall device complexity and spatial arrangement difficulty increase

Engineering Contradiction:
Improvepower transmission switching capabilityVSAvoidspatial arrangement
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by separating the transmission engagement device onto a third axis that is distinct from both the first axis (distribution differential gear mechanism) and the second axis (rotary electric machine). This independent axial placement allows the transmission engagement device to independently control power transmission between the distribution differential gear mechanism and output member without interfering with the rotary electric machine's operation, thereby achieving versatile power transmission switching capability

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4215390B1Drive device for vehicle
Publication Date: 2025.09.10 AISIN CORP
  • EP4215390B1 patent drawingFigure 1
  • EP4215390B1 patent drawingFigure 2
  • EP4215390B1 patent drawingFigure 3

AI summary

A transmission mechanism (T) transmits rotation transmitted from a distribution differential gear mechanism (SP) to an output member (O1). The distribution differential gear mechanism (SP), a first distribution output gear (SG1), and a first engagement device (CL1) are disposed on a first axis (X1). A first rotary electric machine (MG1) and a first rotary electric machine drive gear (DG1) are disposed on a second axis (X2). A transmission engagement device (CLt) of the transmission mechanism (T) is disposed on a third axis (X3). An axial direction (L) of the first rotary electric machine (MG1) includes a first axial side (L1) where the first rotary electric machine (MG1) is disposed with respect to the first rotary electric machine drive gear (DG1), and a second axial side (L2) opposite to the first axial side (L1). The distribution differential gear mechanism (SP) is disposed on the second axial side (L2) of the first distribution output gear (SG1) and the first engagement device (CL1).