Rotation Angle Detection Device Thermal Stress Management
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Solution Overview
Problem
Existing rotation angle detection devices face issues with stress concentration and disconnection of lead terminals due to thermal expansion, leading to reduced reliability and detection accuracy.
Innovation Solution
The rotation angle detection device features a magnetic detection member with lead terminals bonded to lead terminal connecting portions on the wiring members, allowing the sensor body to slide relative to the holding member, thereby minimizing stress concentration and preventing disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the lead terminals are bent into an L-shape to connect the magnetic detection member to the wiring members, then the electrical connection is achieved, but stress concentration occurs at the bent portions leading to potential breakage
Solution Approach 1:
The lead terminal is divided into multiple linear sections rather than being bent into an L-shape. This segmentation eliminates the bent portion that causes stress concentration, while still achieving the electrical connection function through the linear arrangement of terminal portions.
Solution Approach 2:
Instead of bending the lead terminal to achieve connection (conventional approach), the invention inverts the approach by using a linear configuration with multiple terminal portions that extend in the same direction, eliminating the need for bent portions while maintaining connectivity.
2Temperature
If the holding member is elongated and contracted by heat, then thermal expansion is accommodated, but the lead terminals are stressed repeatedly leading to disconnection
Solution Approach 1:
The magnetic detection member is configured to be movable in the longitudinal direction relative to the holding member. This dynamic capability allows the member to adjust its position during thermal expansion and contraction, preventing repeated stress on the lead terminals while accommodating temperature changes.
Solution Approach 2:
The linearly arranged terminal portions act as an intermediary mechanism between the magnetic detection member and the wiring members. This configuration allows thermal expansion to be accommodated through positional adjustment rather than transmitting stress directly to the connection points.
3Stability of the object's composition
If the magnetic detection member is firmly fixed to the holding member, then positioning stability is achieved, but stress is transmitted to the lead terminals during thermal changes
Solution Approach 1:
The magnetic detection member transitions from a fixed state to a movable state in the longitudinal direction. This allows the member to maintain stable positioning in transverse directions while accommodating thermal expansion through longitudinal movement, preventing stress transmission to the lead terminals.
Solution Approach 2:
The positional parameters of the magnetic detection member are made changeable in the longitudinal direction. This parameter change capability allows the system to adapt to thermal expansion while maintaining stable electrical connections, as the member can shift position without stressing the lead terminals.
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 enhances the reliability and accuracy of rotation angle detection by preventing stress concentration and disconnection of lead terminals, even during thermal expansion and contraction.
Implementation Method 1
The distal end portions of the lead terminals A18 of the magnetic detection member A12 are laid on the lead terminal connecting portions A14a in the Y-axis direction and bonded to each other by a welding method.
Data Source
AI summary
A rotation angle detection device may include a magnetic detection member that is configured to detect a rotation angle of a rotation member, a holding member holding the magnetic detection member, and a plurality of wiring members for magnetic detection that are attached to the holding member and are connected to the magnetic detection member. The magnetic detection member has a flat plate-shaped body portion, and a plurality of lead terminals. The holding member holds the body portion of the magnetic detection member in a manner that the body portion can longitudinally slide relative to the holding member. The wiring members for magnetic detection respectively have lead terminal connecting portions. The lead terminals of the magnetic detection member are laid on the lead terminal connecting portions of the wiring members for magnetic detection and bonded thereto.