Hybrid Power Distribution Shaft Layout for Compact EV Transmissions

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Solution Overview

Problem

The contradiction between transmission efficiency and spatial arrangement in hybrid electric vehicles is unresolved due to the integration of engines and motors, leading to increased axial size, complex control strategies, and reduced power performance.

Innovation Solution

A hybrid power-driven system with a power distribution shaft independently disposed from the transmission mechanism and motor, allowing direct transmission paths between the motor and the input shaft or main reducer, minimizing overlap and optimizing spatial arrangement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the motor is integrated with the transmission mechanism in hybrid electric vehicles, then the power performance is improved, but the axial size increases and spatial arrangement becomes complex

Engineering Contradiction:
Improvepower performanceVSAvoidaxial size
Core Design Contradiction:
PowerVSLength of moving object

Solution Approach 1:

The patent transitions from traditional axial integration to radial spatial arrangement. The power distribution shaft is positioned radially adjacent to the transmission mechanism, with gears meshing in the radial direction rather than extending axially. This dimensional change allows the motor and transmission to share space radially, reducing overall axial length while maintaining power integration benefits

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

Solution Approach 2:

The patent implements nested spatial arrangement where the power distribution shaft and its associated gears are positioned within the radial envelope of the transmission mechanism. The first gear on the power distribution shaft meshes with the input gear of the transmission, creating a compact nested configuration that integrates multiple power paths without increasing axial footprint

Inventive Principle:
Principle #7Nested doll (Nesting)

2Power

If the motor and transmission are integrated, then power performance improves, but the control strategy becomes complex

Engineering Contradiction:
Improvepower performanceVSAvoidcontrol strategy
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent segments the power transmission paths into distinct, clearly defined routes. The power distribution shaft with its first and second gears creates separate meshing paths: one path from the input gear through the first gear to the output shaft, and another path from the input gear through the second gear to the main reducer. This segmentation makes control strategies more manageable by providing clear, discrete power flow options

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The power distribution shaft serves multiple functions simultaneously: it transmits power from the motor to the transmission input shaft via the first gear, provides an alternative power path to the main reducer via the second gear, and enables flexible mode switching between different power sources. This multi-functionality reduces control complexity by using a single component to manage multiple power distribution scenarios

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

3Power

If the motor and transmission are integrated, then power performance improves, but the system size and weight increase

Engineering Contradiction:
Improvepower performanceVSAvoidsystem weight
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The patent merges the motor power transmission function with the existing transmission mechanism by introducing a power distribution shaft that radially integrates with the transmission gears. The first gear on the power distribution shaft meshes with the input gear, while the second gear meshes with the main reducer, creating a combined system that shares common components and reduces overall weight compared to separate motor and transmission systems

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

By transitioning to radial spatial arrangement instead of axial extension, the patent reduces the overall system envelope. The power distribution shaft and its gears are positioned radially within the transmission mechanism's footprint, allowing better space utilization and reducing the total volume and weight of the integrated power system

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

Data Source

PatentEP4635768A1Hybrid power-driven system and vehicle
Publication Date: 2025.10.22 BYD CO LTD
  • EP4635768A1 patent drawingFigure 1
  • EP4635768A1 patent drawingFigure 2
  • EP4635768A1 patent drawingFigure 3

AI summary

A hybrid power-driven system and a vehicle are provided. The hybrid power-driven system includes an engine, a transmission, and a motor power apparatus. The transmission includes a transmission mechanism and a main reducer. The motor power apparatus includes a motor and a power distribution mechanism. The power distribution mechanism includes a power distribution shaft, a mode selection apparatus, a first transmission apparatus, and a second transmission apparatus. The power distribution shaft is disposed independently from the transmission mechanism, and the power distribution shaft is disposed independently from the motor. A motor driven gear configured to receive power of the motor is disposed on the power distribution shaft.