Vehicle Drive Unit Coupler Layout for Rolling and Pitching Stability

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Solution Overview

Problem

Electric trucks face challenges with increased driving torque and larger moment during rolling or pitching, requiring higher reliability and larger, heavier support devices, which compromise stability and increase weight.

Innovation Solution

A vehicle drive apparatus with a drive unit housing supported by two couplers on the motor-side and two couplers on the differential-side, arranged to form a trapezoid configuration, reducing the moment on couplers and allowing for lower rigidity and weight, thereby improving stability without increasing size or weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the drive unit is supported by conventional support devices, then the reliability is improved, but the size and weight of the support devices increase

Engineering Contradiction:
ImprovereliabilityVSAvoidweight of support device
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent applies asymmetry by positioning the two couplers of the motor-side support at different distances from the centerline of the drive unit in the vehicle width direction. Specifically, one coupler is positioned farther from the centerline than the other, creating an asymmetric arrangement that optimizes the moment distribution during rolling while maintaining reliability

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent utilizes the vehicle width direction as an additional dimension for coupler arrangement. By positioning couplers at different lateral distances from the centerline rather than only at different longitudinal positions, the design creates a more efficient spatial distribution that reduces the moment of inertia and supports the drive unit with reduced size and weight

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

2Reliability

If the drive unit is supported by conventional support devices, then the reliability is improved, but the size of the support devices increases

Engineering Contradiction:
ImprovereliabilityVSAvoidsize of support device
Core Design Contradiction:
ReliabilityVSShape

Solution Approach 1:

The asymmetric positioning of couplers in the vehicle width direction allows for a more compact support device design. By optimizing the lateral distribution of couplers, the support structure achieves the required reliability with reduced dimensions, particularly in the width direction

Inventive Principle:
Principle #4Asymmetry

3Weight of stationary object

If the couplers are arranged closer to the center of rolling, then the size and weight of couplers can be reduced, but the stability of the drive unit during rolling deteriorates

Engineering Contradiction:
Improveweight of couplerVSAvoidstability during rolling
Core Design Contradiction:
Weight of stationary objectVSStability of the object's composition

Solution Approach 1:

The patent shifts the optimization from longitudinal positioning to lateral positioning in the vehicle width direction. By arranging couplers at different distances from the centerline in the width direction, the design maintains stability during rolling while allowing for reduced coupler size and weight through optimized moment distribution

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

4Stability of the object's composition

If the rigidity requirement of couplers is increased, then the stability during rolling is improved, but the size and weight of couplers increase

Engineering Contradiction:
Improvestability during rollingVSAvoidweight of coupler
Core Design Contradiction:
Stability of the object's compositionVSWeight of stationary object

Solution Approach 1:

The asymmetric coupler arrangement optimizes the moment distribution during rolling, allowing one coupler to bear more load while the other bears less. This asymmetric load distribution enables the use of couplers with lower individual rigidity requirements while maintaining overall system stability, thereby reducing the weight and size of the couplers

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4079552B1Vehicle drive apparatus
Publication Date: 2024.08.21 DAIMLER TRUCK AG
  • EP4079552B1 patent drawingFigure 1
  • EP4079552B1 patent drawingFigure 2
  • EP4079552B1 patent drawingFigure 3

AI summary

There is provided a vehicle drive apparatus capable of improving the stability of a drive unit during vehicle rolling or the like while reducing the increase in size and weight of a support device. A vehicle drive apparatus includes a motor 10 that generates a driving force in a vehicle with a ladder frame, a transmission 20 that changes the driving force transmitted from the motor 10, and a differential 14 that transmits the driving force transmitted from the transmission 20, and further includes: a drive unit housing 25; a motor-side support 28 coupling the drive unit housing 25 to the ladder frame 2 by two couplers 28a and 28b arranged in a motor-side end region of the drive unit housing 25; and a differential-side support 29 coupling the drive unit housing 25 to the ladder frame 2 in the differential-side end region of the drive unit housing 25, the two couplers 28a and 28b of the motor-side support 28 being arranged on outer side in a vehicle width direction than the differential-side support 29.