Centrally Driven Trailer Axle Unit with Single Motor

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Solution Overview

Problem

Trailer axles driven by wheel hub motors require significant installation space, leading to increased costs and reduced driving stability due to the need for longer tracks or reduced spring center, and are hindered by heavy, space-consuming hydraulic lines.

Innovation Solution

A center drive axle unit with a single motor and two drive shafts, where the motor is housed and converts energy into torque, transmitting it through input and output sections designed for compactness and efficient torque transfer, using a hydraulic or electric motor with decoupled output shafts to minimize space and maximize stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If wheel hub motors are used to drive each wheel, then driving capability is improved, but installation space requirement increases

Engineering Contradiction:
Improvedriving capabilityVSAvoidinstallation space
Core Design Contradiction:
PowerVSArea of stationary object

Solution Approach 1:

The patent merges two separate wheel hub motors into a single central motor that drives both wheels through a differential mechanism. This consolidation reduces the total installation space while maintaining the driving capability of individually powered wheels, directly resolving the contradiction between power and space requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The invention relocates the motor from the wheel hub position to the central axle position, changing the spatial dimension of motor placement. This dimensional shift allows the motor to be positioned where space is more abundant, reducing the overall footprint while still delivering power to both wheels effectively.

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

2Area of stationary object

If track width is increased to accommodate wheel hub motors, then installation space is improved, but driving stability deteriorates due to reduced spring center

Engineering Contradiction:
Improveinstallation spaceVSAvoiddriving stability
Core Design Contradiction:
Area of stationary objectVSStability of the object's composition

Solution Approach 1:

Instead of increasing track width to accommodate motors (which harms stability), the invention inverts the approach by placing the motor centrally and using a differential to drive the wheels. This maintains the original track width and spring center geometry, preserving driving stability while still providing powered drive to both wheels.

Inventive Principle:
Principle #13The other way round (Inversion)

3Power

If multiple wheel hub motors are installed with long hydraulic lines, then driving capability is improved, but device complexity and weight increase

Engineering Contradiction:
Improvedriving capabilityVSAvoidhydraulic line configuration
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent combines the functions of multiple motors and their associated hydraulic lines into a single motor with a centralized hydraulic connection. This eliminates the need for multiple long hydraulic lines running to each wheel, significantly reducing system complexity and weight while maintaining the capability to drive both wheels independently through the differential.

Inventive Principle:
Principle #5Merging (Combining)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution reduces installation space requirements, lowers costs, and enhances driving stability by allowing greater separation of axle support points, minimizing tire wear, and achieving high power density and efficiency while avoiding electromagnetic interference.

Implementation Method 1

The sole motor (2) of the axle unit is an energy converter arranged inside a housing, which converts potential energy, such as electrical energy or voltage, or fluid pressure, into kinetic energy, in particular torque.

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

In a preferred embodiment, the motor is a hydraulic motor. This achieves a high power density of the axle unit, so that weight can be saved.

Methodology Applied
Scientific EffectHydraulic force conversion: Hydraulic Press

Data Source

PatentEP3480047A1Centrally driven trailer axle
Publication Date: 2019.05.08 SAF HOLLAND GMBH
  • EP3480047A1 patent drawingFigure 1
  • EP3480047A1 patent drawingFigure 2
  • EP3480047A1 patent drawing

AI summary

The invention relates to an axle unit (1), in particular for trailer axles, comprising a motor (2) and two drive shafts (3,4), wherein the drive shafts (3,4) each have an inlet section (5) and each have an outlet section (6), and the one motor (2) is designed to exert a torque on the two drive shafts (3,4) via the inlet sections (5) and the outlet section (6) of the respective drive shaft (3,4) is designed to drive each wheel directly/indirectly.