Stator Ring Protrusions for EPS Sensor Coupling Stability
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Solution Overview
Problem
The existing sensing devices for Electronic Power Steering Systems face a challenge in maintaining a stable coupling force between the stator holder and stator ring due to rotational forces, which can lead to a gap formation, especially under varying temperature conditions required for R-type EPS systems.
Innovation Solution
A sensing device is designed with a stator ring featuring protrusions on its outer surface, which are caulkingly fixed to the stator holder, increasing the coupling force and preventing movement of the stator ring during rotation, utilizing a synthetic resin for the stator ring-fixing part and metal for the shaft-fixing part, with a specific ratio of protrusion distance to width and inclined surfaces for enhanced contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the coupling force between stator holder and stator ring is increased to prevent gap formation, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The stator ring is divided into multiple segments with individual protrusions, allowing distributed coupling points that enhance reliability without requiring a completely redesigned complex structure. Each protrusion acts as an independent coupling element.
Solution Approach 2:
The coupling mechanism transitions from a single-plane interface to a multi-dimensional solution by adding protrusions that extend radially outward and engage with corresponding features in the stator holder, creating coupling in multiple spatial dimensions.
2Strength
If protrusions are added to the stator ring to increase caulking force, then the coupling strength is improved, but the manufacturing complexity increases
Solution Approach 1:
The protrusions are pre-formed as integral features of the stator ring during the molding process, rather than being added as separate components. This preliminary formation of coupling features simplifies assembly while achieving the required caulking force.
Solution Approach 2:
The stator ring is formed using composite materials that allow for the integration of protrusion features during molding, combining structural integrity with enhanced coupling capabilities without requiring complex post-processing manufacturing steps.
3Measurement precision
If the stator ring is firmly coupled to prevent movement, then the measurement precision is improved, but the ease of operation decreases
Solution Approach 1:
The coupling is segmented into multiple discrete protrusion points distributed around the stator ring, allowing for progressive engagement during assembly rather than requiring complete alignment of a single large interface, thus improving ease of operation.
Solution Approach 2:
The protrusions act as intermediary coupling elements between the stator ring and stator holder, providing localized engagement points that facilitate gradual assembly while ensuring precise final positioning for accurate torque measurement.
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 increased caulking force effectively minimizes the movement of the stator ring due to rotation, ensuring a stable coupling and improved reliability under diverse temperature conditions.
Implementation Method 1
The protrusions are fixed to an outer surface of the stator ring-fixing part in a caulking manner
Implementation Method 2
a sensing unit configured to measure a magnetic field generated between a rotor and a stator
Data Source
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AI summary
An embodiment relates to a sensing device comprising: a rotor; and a stator arranged on the outer side of the rotor, wherein the stator comprises a stator holder and a stator ring arranged on the stator holder; the stator ring comprises a body, a plurality of teeth formed to protrude from the inner peripheral surface of the body, and a protrusion part formed to protrude from the outer peripheral surface of the body; and, when seen in the radial direction, the protrusion part is arranged between the teeth and comprises at least two protrusions arranged to be spaced from each other. Accordingly, the coupling force between the stator holder and the stator ring can be improved.