Vehicle Transmission Layout With Lateral Inverter Dry Compartment

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Solution Overview

Problem

Existing motor vehicle transmissions with integrated electrical machines and power electronics struggle to maintain a compact overall height without increasing external dimensions, which affects ground clearance and installation space efficiency.

Innovation Solution

The transmission design incorporates a power electronics module with a carrier element that integrates the inverter and AC/DC voltage connections, allowing for efficient use of installation space by positioning the power electronics module laterally within the gearbox housing, thus reducing the overall cross-section and height, and includes features like pressure compensation and ventilation to prevent moisture accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the power electronics module is integrated within the gearbox housing, then the overall height and ground clearance are reduced, but the installation space utilization becomes more constrained

Engineering Contradiction:
Improveoverall heightVSAvoidinstallation space utilization
Core Design Contradiction:
Length of stationary objectVSArea of stationary object

Solution Approach 1:

The power electronics module is nested within the gearbox housing by utilizing the hollow space formed by the rounded wheelset cross-section. The mounting element is positioned concentrically around the wheelset, creating a dry compartment that houses the inverter without increasing the external dimensions of the gearbox.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The power electronics module is arranged laterally on the transmission rather than above or below, utilizing the radial space around the wheelset. This dimensional repositioning allows efficient use of the rounded cross-section space while maintaining compact external height.

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

2Area of stationary object

If the power electronics module is positioned laterally on the transmission, then the cross-section increases only slightly, but the module requires access for assembly and maintenance

Engineering Contradiction:
Improvecross-sectionVSAvoidassembly and maintenance access
Core Design Contradiction:
Area of stationary objectVSEase of repair

Solution Approach 1:

The mounting element is designed with a detachable cover that can be removed to provide access to the inverter and AC voltage connection. This segmentation allows the power electronics module to be integrated laterally while maintaining ease of assembly and maintenance by enabling access without detaching the entire module from the gearbox.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the inverter is housed in a separate housing, then the installation space is increased, but the overall compactness and ground clearance are compromised

Engineering Contradiction:
Improveinstallation spaceVSAvoidground clearance
Core Design Contradiction:
Ease of operationVSLength of stationary object

Solution Approach 1:

The housing for the power electronics module is merged with the gearbox housing by positioning the mounting element within the gearbox's external dimensions. The dry compartment is formed by the interaction of the gearbox housing outer wall and the mounting element, eliminating the need for a separate external housing while providing adequate installation space for the inverter.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3658401B1Transmission for a motor vehicle
Publication Date: 2024.11.13 ZF FRIEDRICHSHAFEN AG
  • EP3658401B1 patent drawingFigure 1
  • EP3658401B1 patent drawingFigure 2
  • EP3658401B1 patent drawingFigure 3

AI summary

The invention relates to a transmission (G) for a motor vehicle, the transmission (G) comprising a housing (GG), a wheel set (RS) arranged inside the housing (GG) in order to form a plurality of gears between a drive shaft (GW1) and an output shaft (GW2) of the transmission (G), an electric motor (EM) operatively connected to the drive shaft (GW1), the output shaft (GW2) or an element (RSx) of the wheel set (RS) and a power electronics module (LE). The power electronics module (LE) comprises a carrier element (S) having an inner face (Sl) and an outer face (SA), a d.c. voltage connection (DC), an inverter (INV) and an a.c. voltage connection (AC). The housing (GG) comprises on an outer wall (GGA) a region (GGE) to accommodate the power electronics module (LE), which region can be closed by the support element (S) of the power electronics module (LE). The region (GGE) of the housing (GG) and the inner face (Sl) of the carrier element (S) form a dry space (TR) to accommodate the inverter (INV), being fastened to the carrier element (S), and the region (GGE) of the housing (GG) separates the wheel set (RS) at least in some sections from the dry space (TR). The invention further relates to a motor vehicle having such a transmission (G).