Electric Machine Coupling With Axial Length Compensation
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Solution Overview
Problem
Electric motor designs for vehicles face challenges in achieving a compact, lightweight, and robust structure while maintaining precise alignment of magnetic components, as external loads and inertial forces can cause unwanted displacements and deformations, affecting magnetic flux and efficiency.
Innovation Solution
Incorporating an axially elastic length-compensation element between the rotor and output element of the electric machine, which allows for targeted axial length compensation without transmitting displacements to the rotor, thereby preventing unwanted axial displacements and deformations, and using a torque-transmitting connection to reduce external forces on the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the structure of the electric motor is made particularly stiff and robust to ensure precise alignment of magnetic components, then the alignment precision and reliability are improved, but the weight, volume, and cost increase
Solution Approach 1:
The patent introduces a bearing as an intermediary component between the rotor and stator to maintain precise alignment without requiring the entire structure to be stiff. The bearing specifically supports the rotor shaft, allowing precise radial alignment while keeping the overall structure lighter and more compact.
Solution Approach 2:
Instead of making the entire motor structure uniformly stiff, the patent applies precision requirements locally at critical positions (rotor-stator interface) using bearings, while other parts of the structure can be optimized for weight and compactness. This localized precision approach resolves the contradiction between overall structural stiffness and weight reduction.
2Manufacturing precision
If the structure of the electric motor is made particularly stiff and robust to ensure precise alignment of magnetic components, then the alignment precision and reliability are improved, but the device complexity and cost increase
Solution Approach 1:
The bearing serves as a specialized intermediary component that handles the alignment function, allowing the rest of the motor structure to be simpler. This division of labor reduces overall device complexity while maintaining precise alignment through the bearing's inherent design.
Solution Approach 2:
The patent changes the functional parameters of specific components (using bearings with specific clearance and precision ratings) to achieve alignment precision without requiring complex structural designs. This parameter-based approach simplifies the overall device complexity.
3Reliability
If the structure of the electric motor is made particularly stiff and robust to ensure precise alignment of magnetic components, then the reliability under external loads is improved, but the compactness and power density decrease
Solution Approach 1:
The bearing acts as a compact intermediary that provides reliable support under external loads without requiring large structural dimensions. This allows the motor to maintain compactness while achieving the necessary reliability for alignment under various operating conditions.
Solution Approach 2:
The patent may employ composite materials or optimized material selections for the bearing and surrounding structures to achieve high strength-to-volume ratios, ensuring reliability under external loads while minimizing the volume required for the load-bearing structure.
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
This solution enables a more delicate, space-saving, and cost-effective electric machine design that maintains required positioning accuracy, reducing the need for stiff load-bearing components and minimizing the impact of external forces on the motor's alignment and efficiency.
Implementation Method 1
an axially elastic length-compensation element for transmitting torque is arranged between the rotor of the electric machine and the output element
Data Source
AI summary
An electric machine arrangement including an electric machine for driving an electrically drivable motor vehicle, having a stator and having a rotor, and also including an output element that is in rotationally fixed contact with the rotor. An axially elastic length-compensation element for transmitting a torque is arranged between the electric machine and the output element.