Actuator Magnet Attachment Using Plastic Casing
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Solution Overview
Problem
Existing actuators with rotation angle sensors face challenges in securely attaching magnets to rotors, particularly due to complex manufacturing processes and potential play between the magnet and rotor, which can lead to signal distortion with temperature changes.
Innovation Solution
A magnet embedded in a plastic casing is attached to the sensor part using methods like ultrasonic welding or gluing, allowing for easy and reliable attachment without play, and can be mass-produced independently for various actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the magnet is attached to the rotor by means of screws, then the magnet can be securely fixed to the rotor, but the manufacturing process becomes highly complex
Solution Approach 1:
The magnet is integrated directly into the rotor as a single piece, eliminating the need for separate attachment mechanisms like screws. The magnet forms one unified component with the rotor, simplifying the overall structure and manufacturing process while maintaining secure fixation.
Solution Approach 2:
The rotor is designed to serve multiple functions: it provides the rotational mechanical function and simultaneously houses the magnet as an integrated component. This multi-functionality eliminates the need for separate magnet attachment structures.
2Reliability
If the magnet is cast into the plastic material of the rotor, then the magnet can be securely fixed to the rotor, but the manufacturing process becomes complex and requires specific adaptation to different customer wishes
Solution Approach 1:
The magnet and rotor are combined into a single integrated component, eliminating the need for complex casting processes. This integration is achieved through simple assembly methods rather than complex injection molding or casting operations.
Solution Approach 2:
The magnet and rotor are manufactured as separate components and then assembled together, rather than being cast as a single piece. This segmentation allows for simpler, more flexible manufacturing of each component independently, reducing overall manufacturing complexity.
3Ease of manufacture
If a deformable edge is used to secure the magnet to the rotor by deforming the edge to encompass the magnet, then the magnet can be attached to the rotor, but the plastic material springs back after deformation causing play between the rotor and magnet
Solution Approach 1:
The magnet is integrated with the rotor to form a unified structure, eliminating the need for deformable edges and the associated spring-back problems. The integrated design ensures precise positioning without material deformation.
Solution Approach 2:
An intermediary element or structure is introduced between the magnet and rotor to maintain precise positioning. This intermediary prevents the spring-back effect and ensures the magnet remains firmly positioned without play.
4Ease of manufacture
If the deformation is used to secure the magnet to the rotor, then the magnet can be attached to the rotor, but the deformation changes the properties of the plastic material so that with temperature changes the plastic material relaxes and the firm fit of the magnet is no longer assured
Solution Approach 1:
The magnet and rotor are integrated as a single component, eliminating the need for deformable plastic edges. This integration ensures that temperature changes affect the entire assembly uniformly, maintaining the firm fit of the magnet without material relaxation.
Solution Approach 2:
The design avoids relying on changes in plastic material properties due to deformation. Instead, the magnet attachment is achieved through a design that maintains stable dimensional characteristics across temperature variations, ensuring consistent fit and position.
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 provides a simple, reliable, and temperature-stable attachment method for the magnet, ensuring accurate rotation angle sensing without play or signal distortion, and allows for flexible manufacturing without altering the rotation angle sensor.
Implementation Method 1
The plastic casing accommodating the magnet can be very easily attached to the first sensor part, for example by means of ultrasonic welding
Implementation Method 2
Depending on the position of the magnet of the rotor, the magnetic field acting on the magnetically sensitive element changes so that the magnetically sensitive element emits a corresponding electrical signal
Data Source
AI summary
In the case of an actuator having a rotation angle sensor with a magnet, no satisfying solution has yet been found for the attachment of the magnet. The invention relates to an actuator having a rotation angle sensor, the magnet of the rotation angle sensor being provided with a plastic cover. The plastic cover and magnet may be easily connected to a first sensor part of the rotation angle sensor of the actuator. The actuator with the rotation angle sensor can particularly be used in motor vehicles.