Electric Driveline Torque Split Using Planetary Gear Control
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Solution Overview
Problem
Existing driveline arrangements in working machines, such as articulated haulers, face challenges in achieving optimal torque distribution for varying load conditions, leading to poor maneuverability and excessive wear due to fixed torque distributions that do not adapt to different operating scenarios.
Innovation Solution
A driveline arrangement featuring a first electric machine and a continuously variable torque distribution system with a primary planetary gear set and a second electric machine, allowing controllable torque distribution between the front and rear wheel axles, utilizing a single energy storage system for both machines, and incorporating additional planetary gear sets and gear shifting arrangements for enhanced versatility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed torque distribution is used in the driveline arrangement, then the structure is simple and cost-effective, but the torque distribution cannot adapt to different operating conditions leading to poor maneuverability and excessive wear
Solution Approach 1:
The patent applies the dynamics principle by replacing the fixed torque distribution mechanism with a dynamic control system using two electric machines. The first electric machine provides torque to the rear axle while the second electric machine controls torque distribution to the front axle, enabling real-time adaptation to different operating conditions such as loaded/unloaded states, forward/reverse motion, and various ground conditions.
Solution Approach 2:
The invention substitutes traditional mechanical torque distribution mechanisms (such as fixed differentials and mechanical linkages) with an electric machine-based control system. This replacement allows for more precise and flexible torque control without the mechanical complexity and wear associated with traditional systems, while maintaining cost-effectiveness through the use of electric motors.
2Ease of operation
If torque is distributed to front wheels for unloaded 6x4 condition, then front wheel propulsion is improved, but rear wheels receive insufficient torque causing locking and excessive wear
Solution Approach 1:
The control system continuously monitors operating conditions and adjusts torque distribution accordingly. Based on feedback about vehicle load, speed, and steering input, the controller optimizes the torque split between front and rear axles, preventing differential locking by ensuring adequate torque to all wheels under varying conditions.
Solution Approach 2:
The system dynamically changes torque distribution parameters based on operating conditions. The controller adjusts the torque output parameters of both electric machines in real-time, transitioning from front-wheel-biased distribution during unloaded 6x4 operation to more balanced or rear-biased distribution when loaded or during 6x6 operation.
3Power
If torque is distributed to rear wheels for loaded 6x6 condition, then rear wheel propulsion is improved, but front wheels receive insufficient torque for engine braking and reversing
Solution Approach 1:
The dual electric machine system provides universal torque distribution capability that serves multiple functions: it can deliver high rear axle torque for loaded 6x6 propulsion, switch to front-biased distribution for engine braking during downhill descent, provide balanced torque for reversing operations, and adapt to various intermediate operating conditions, making the driveline versatile across all work scenarios.
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 driveline arrangement provides a cost-effective, environmentally friendly, and versatile solution that adapts to a wide range of operating conditions, optimizing torque distribution and reducing wear, while enabling efficient electric propulsion and maneuverability.
Implementation Method 1
a first electric machine (102) arranged to propel the working machine (10)
Implementation Method 2
a second electric machine (118) connected to the primary sun gear (110)
Implementation Method 3
a primary planetary gear set (108) comprising a primary sun gear (110), a primary ring gear (112) and a primary planet carrier (114) carrying a set of planet gear units (116), wherein the planet gear units are in meshing engagement with the primary sun gear and the primary ring gear
Data Source
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AI summary
The present invention relates to a driveline arrangement, comprising a first electric machine, and a continuously variable torque distribution arrangement configured to controllably direct a torque from the first electric machine to a front wheel axle and at least one rear wheel axle, the continuously variable torque distribution arrangement comprising a main shaft connectable to the first electric machine and to the at least one rear wheel axle, a primary planetary gear set comprising a primary sun gear, a primary ring gear and a primary planet carrier carrying a set of planet gear units, wherein the planet gear units are in meshing engagement with the primary sun gear and the primary ring gear, a second electric machine connected to the primary sun gear, and a gear stage comprising a first gear wheel operatively connected to the primary ring gear, and a second gear wheel connectable to the front wheel axle, the first gear wheel being in meshing engagement with the second gear wheel, wherein the primary planet carrier is operatively connected to the main shaft.