Hybrid Gearbox Layout for Reduced Longitudinal Transmission Length

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Solution Overview

Problem

Existing hybrid transmissions face challenges in achieving the most compact design and high power density, particularly along the main transmission shaft, which affects their efficiency and integration within vehicle space constraints.

Innovation Solution

The hybrid transmission design incorporates a parallel arrangement of key components such as the electric machine, power electronics, and control units, optimizing their placement to minimize axial space usage, including an L-shaped power electronics layout and overlapping components to maximize integration and power density, while ensuring efficient packaging and crash safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If components are arranged in a conventional layout, then ease of manufacture is improved, but the transmission length in the longitudinal direction increases

Engineering Contradiction:
Improvetransmission length in longitudinal directionVSAvoidmanufacturing complexity
Core Design Contradiction:
Length of moving objectVSEase of manufacture

Solution Approach 1:

The patent transitions from a conventional longitudinal arrangement to a three-dimensional spatial configuration where the electric machine is positioned laterally adjacent to the countershaft and power electronics are arranged in multiple layers (stator above countershaft, rotor below). This dimensional reorganization reduces the longitudinal footprint while maintaining functional relationships through vertical and lateral positioning.

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

Solution Approach 2:

The patent implements nested positioning where the stator is arranged above the countershaft and the rotor is arranged below the countershaft, creating a vertically stacked configuration. The power electronics are similarly nested with the control unit positioned adjacent to and overlapping with the electric machine components, maximizing space utilization in the longitudinal direction.

Inventive Principle:
Principle #7Nested doll (Nesting)

2Power

If components are integrated closely, then power density is improved, but device complexity increases

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

Solution Approach 1:

The patent merges multiple functional components into a compact integrated assembly where the electric machine (stator and rotor), power electronics (inverter and control unit), and transmission elements (countershaft) are positioned in close proximity with overlapping arrangements. This consolidation achieves high power density by eliminating unnecessary spacing while maintaining functional independence of each subsystem.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4251450B1Hybrid gearbox for a vehicle
Publication Date: 2024.01.31 MERCEDES BENZ GROUP AG
  • EP4251450B1 patent drawingFigure 1~2
  • EP4251450B1 patent drawingFigure 3

AI summary

The invention relates to a hybrid gearbox (1) for a vehicle, said hybrid gearbox comprising: a gearbox input shaft (5) that extends in a transverse direction (y); at least one countershaft (6) positioned parallel to the gearbox input shaft (5); a clutch device (7) which is positioned coaxially with respect to the gearbox input shaft (5) and which has at least one clutch; a differential which has a differential input gear (4), wherein an axis of rotation (19) of the differential input gear is positioned parallel to the gearbox input shaft (5); an electric machine (3) which has a rotor and a stator, wherein a rotor rotational axis (9) is positioned parallel to the gearbox input shaft (5); a gearbox control device (11), wherein, as viewed in a longitudinal direction (x) which is perpendicular to the transverse direction (y), the differential input gear (4), the gearbox input shaft (5), and a gearbox controller comprising the gearbox control device (11) are arranged in succession in the sequence specified.