Hollow-Translator Linear Electrical Machine With Fluid Bearing Alignment
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Solution Overview
Problem
Existing linear electrical machines used in actuator applications face limitations such as high inertia, complex construction, increased cost, and reduced peak frequencies due to the need for additional mechanical components like airbags or pneumatic cylinders, which compromise the accuracy and efficiency of simulating road loads for vehicle testing.
Innovation Solution
A linear electrical machine design featuring a stator with a central core and a hollow translator, utilizing fluid bearings for coaxial location and reduced translator mass, along with a preload chamber for balancing forces, eliminates the need for additional mechanical elements, reducing inertia and complexity while maintaining coaxial alignment and enabling higher frequency operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If additional mechanical components like airbags or pneumatic cylinders are added to linear electrical machines, then static load application capability is improved, but device complexity and inertia increase
Solution Approach 1:
The invention extracts and eliminates the need for separate mechanical components (airbags, pneumatic cylinders) by integrating the static load application function directly into the linear electrical machine's electromagnetic system. The electromagnetic actuator is controlled to provide both dynamic and static force components through a single integrated device, thereby reducing overall device complexity while maintaining force application capability.
Solution Approach 2:
The invention merges the function of separate mechanical components (airbags or pneumatic cylinders) with the linear electrical machine into a single integrated electromagnetic actuator system. The electromagnetic actuator simultaneously provides both dynamic motion control and static load application, combining multiple functions into one device and eliminating the need for additional mechanical elements.
2Force
If additional mechanical components like airbags or pneumatic cylinders are added to linear electrical machines, then static load application capability is improved, but translator mass and inertia increase
Solution Approach 1:
The invention extracts and removes the need for separate mechanical components (airbags, pneumatic cylinders) that would add mass to the translator. By eliminating these components and integrating their function into the electromagnetic actuator, the translator mass is reduced while maintaining the capability to apply static loads through electromagnetic force control.
3Ease of operation
If spring and pneumatic cylinder arrangements are used, then static force component adjustment is enabled, but mechanical friction and wear increase
Solution Approach 1:
The invention replaces the mechanical system (springs and pneumatic cylinders) with an electromagnetic system. The linear electrical machine uses electromagnetic fields to generate and adjust the static force component, eliminating mechanical contact and friction. The control system adjusts the electromagnetic current to vary the static force component as needed, providing the same adjustment capability without mechanical wear.
4Speed
If servo-hydraulic systems are used to simulate high frequency displacements, then road load simulation capability is improved, but system inertia limits practical frequency to approximately 150 Hz
Solution Approach 1:
The invention replaces the servo-hydraulic system with a linear electrical machine that uses electromagnetic fields to generate motion. This substitution eliminates the heavy hydraulic oil and power pack components that limit frequency response. The electromagnetic actuator has significantly lower moving mass and no fluid inertia, enabling operation at frequencies well above 150 Hz while maintaining the capability to simulate road load displacements.
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 design achieves higher frequency operation with lower mechanical friction and wear, reducing the overall size and cost of the actuator while maintaining precise force application and minimizing resonances, thus enhancing the simulation of road loads for vehicle testing.
Implementation Method 1
at least one fluid bearing between the central core and the translator providing coaxial location of the translator within the stator bore cavity
Implementation Method 2
a linear electrical machine design featuring a stator with a central core and a hollow translator
Data Source
AI summary
A linear electrical machine (LEM) comprising a stator mounted in a housing, the housing and stator defining a working cylinder, a central core within the working cylinder and defining a cylindrical stator bore cavity therebetween, a hollow translator axially movable within the working cylinder, extending into the stator bore cavity and forming an exterior magnetic circuit airgap between the translator and the stator, at least one fluid bearing between the central core and the translator providing a bearing gap, wherein the central core is axially fixed in relation to the stator, wherein the at least one fluid bearing provides coaxial location of the translator and central core.