Eddy Current Brake Rotor Composite Layer Design
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Solution Overview
Problem
Existing clutch devices for hybrid vehicles require separate development and design efforts for electromechanical and electrohydraulic actuation systems, leading to inefficiencies and potential malfunctions due to air gaps in the magnetic circuit.
Innovation Solution
A clutch device with an eddy current brake featuring a brake rotor with both an electrically conductive and magnetic layer, reducing air gaps and enhancing magnetic flux density, thereby increasing braking torque and heat capacity while allowing the same electric motor to be used for both actuator variants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single electric motor is used for both electromechanical and electrohydraulic clutch actuation, then device complexity is reduced, but reliability deteriorates due to air gaps in the magnetic circuit
Solution Approach 1:
The brake rotor is constructed as a composite structure with a non-magnetic base material (e.g., aluminum) and a magnetic layer (e.g., iron or steel coating) applied to its surface. This composite design allows the rotor to be non-magnetic in the bulk (reducing eddy current losses) while having a magnetic surface layer that provides sufficient magnetic flux density for reliable clutch operation, thereby eliminating the air gap problem while maintaining a single actuator design.
2Power
If the air gap between brake rotor and stator is reduced, then magnetic flux density increases, but the risk of contact and malfunction increases
Solution Approach 1:
The brake rotor uses a composite structure with a non-magnetic base material and a magnetic surface layer. The magnetic layer has high permeability that concentrates magnetic flux at the air gap interface, enabling sufficient magnetic flux density for high braking torque even with a larger air gap. This eliminates the need for minimal air gaps while preventing rotor-stator contact.
Solution Approach 2:
The invention changes the magnetic properties of the brake rotor by applying a magnetic layer with high permeability to the surface. This parameter change in material properties allows the magnetic circuit to be more efficient, providing sufficient flux density across a larger air gap, thereby increasing the safe operating distance between rotor and stator.
3Power
If the brake rotor is made entirely of electrically conductive material, then eddy current braking is effective, but heat capacity is insufficient
Solution Approach 1:
The brake rotor is constructed as a composite with a non-magnetic base material (such as aluminum or aluminum alloy) that provides high heat capacity and thermal conductivity, and a magnetic layer (such as iron, steel, or ferrite coating) applied to the surface that provides the necessary magnetic properties for eddy current braking. This composite structure combines the thermal advantages of non-ferrous materials with the magnetic properties of ferrous materials, simultaneously achieving effective braking torque and sufficient heat dissipation capacity.
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 configuration enhances the reliability and efficiency of the clutch device by minimizing air gaps, increasing magnetic flux density, and reducing heat generation, allowing for rapid engine start and torque transmission without wear, while maintaining a compact design.
Implementation Method 1
the brake region has a first layer which is electrically conductive and which has a first lateral face and a second lateral face, the first lateral face facing toward the coil
Implementation Method 2
As the magnetic disk moves in the magnetic field voltages are produced in it by induction, resulting in eddy currents, which in turn produce magnetic currents of their own contrary to the external magnetic field
Implementation Method 3
the brake region has a second layer which is magnetic and which is connected to the second lateral face
Data Source
AI summary
The invention comprises a clutch device having an actuating device, wherein the actuating device has an electrical eddy current brake. The eddy current brake has a brake stator with at least one coil and a brake rotor with a brake region, wherein the brake region has a first layer which is electrically conductive and which has a first lateral face and a second lateral face, the first lateral face facing toward the coil and the second lateral face facing away from the coil. The brake region has a second layer which is magnetic and which is connected to the second lateral face. The invention further comprises a corresponding production method.