Power-Split Axle Drive With Switchable Braking Modes

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Solution Overview

Problem

Existing performance-based axle drives for agricultural vehicles have complex structures and inadequate efficiency for operation and braking, limiting their performance and driving capabilities.

Innovation Solution

A performance-based axle drive system with a simplified structure, incorporating switching elements like clutches and brakes that allow for adjustable torque transfer and operating modes such as 'fully electrical,' 'parking brake,' and 'vehicle axle brake,' enabling efficient operation and improved braking performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a power-split axle drive is implemented for agricultural vehicles, then the forward travel of vehicle axles can be controlled, but the structure becomes complex and efficiency is inadequate

Engineering Contradiction:
Improveforward travel controlVSAvoidstructure
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The drive system is segmented into independent modules: a power-split transmission unit with planetary gears for each axle, allowing separate control of front and rear axle speeds. Each module can operate independently, providing versatile forward travel control while keeping individual component complexity manageable through standardized modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The power-split transmission unit serves multiple functions simultaneously: it provides speed differentiation between axles, enables controlled forward travel, and can operate in various modes (differential drive, locked differential, neutral). This multi-functionality reduces the need for additional separate control mechanisms, thereby managing overall structural complexity

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

2Adaptability or versatility

If a power-split axle drive is implemented, then axle speed control is possible, but operational efficiency is insufficient

Engineering Contradiction:
Improveaxle speed controlVSAvoidoperational efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The system employs dynamically adjustable speed ratios between axles through the planetary transmission mechanism. The speed control is not fixed but can be continuously adjusted based on operational conditions, allowing optimal performance across varying terrain and load conditions, thereby improving operational efficiency while maintaining axle speed control capability

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If a power-split axle drive is implemented, then drive control is possible, but braking efficiency is insufficient

Engineering Contradiction:
Improvedrive controlVSAvoidbraking efficiency
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A braking mechanism is introduced as an intermediary component within the power-split transmission unit. This brake can independently control the rotation of the planetary carrier or sun gear, providing reliable stopping capability without interfering with the normal differential operation. The braking function is integrated into the existing structure, maintaining drive control while ensuring adequate braking efficiency

Inventive Principle:
Principle #24Intermediary (Mediator)

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 system achieves a more efficient and versatile power transmission, allowing for improved operational modes that enhance the vehicle's performance and reduce manufacturing costs by simplifying the structure and distributing braking performance effectively.

Implementation Method 1

The power-split transmission unit (52) has a planetary gear set (108) with a sun gear (102), planet gears (108), and a ring gear (104)

Methodology Applied
Scientific EffectPlanetary gear mechanism: Gear

Implementation Method 2

The switching elements, in particular clutches, are preferably frictionally engaged elements. In this case, a force can be introduced into the connection point between the two components via an actuator, creating a frictional force through which a rotational movement and/or a force and/or a torque can be transmitted

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4215393B1Power-split axle drive and agricultural vehicle
Publication Date: 2025.01.29 DEERE & CO
  • EP4215393B1 patent drawingFigure 1
  • EP4215393B1 patent drawingFigure 2
  • EP4215393B1 patent drawingFigure 3

AI summary

A power-split axle drive (20) for an agricultural vehicle (10), comprising a first auxiliary drive element (50), a first vehicle axle (26), a second vehicle axle (28), and a main drive element (22) for providing torque that can be transmitted to a main gearbox (24) via a first shaft (W1). The main gearbox (24) is connected to the second vehicle axle (28), and at least the second vehicle axle (28) can be driven via the main gearbox (24) by the torque of the main drive element (22). The power-split axle drive includes a power-split gearbox (52). The power-split gearbox (52) is connected to the second vehicle axle (28) and the main gearbox (24) and is connected to the first vehicle axle (26) via a second shaft. The first auxiliary drive element (50) can be connected to the power-split gearbox (52).A first switching element (74) and/or a first brake (76) is arranged on the second shaft (W2). The invention further relates to an agricultural vehicle (10).