Magnetostrictive Torque Sensor With Flexible Coil Protection
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Solution Overview
Problem
Existing torque sensors face issues of damage during assembly due to direct collision with surrounding objects and have a high number of parts, increasing manufacturing costs.
Innovation Solution
A torque measuring device with a casing made of magnetic metal, a rotating shaft with a magnetostrictive effect section, and a torque sensor supported by a holder made of rubber or synthetic resin, which covers the coil unit and is fitted into the casing, eliminating the need for a separate back yoke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the coil unit is directly adhered to the inner peripheral surface of the back yoke, then the torque sensor structure is simplified, but the coil unit may collide with surrounding objects and be damaged during assembly work
Solution Approach 1:
The patent introduces a support member as an intermediary component between the coil unit and the back yoke. This support member has a holding portion that holds the coil unit and a fitting portion that fits into the back yoke, thereby preventing direct contact and potential damage to the coil unit during assembly while maintaining structural integration.
2Measurement precision
If a separate back yoke is used as a magnetic path component, then measurement accuracy is improved, but the number of parts increases and manufacturing cost increases
Solution Approach 1:
The patent combines the back yoke and the support member into a single integrated component. The support member is configured with a fitting portion that fits into the back yoke, allowing these two components to be merged into one piece, thereby reducing the number of parts and manufacturing cost while maintaining the magnetic path function and measurement accuracy.
3Length of moving object
If the coil unit is formed using a flexible substrate, then the thickness of the torque sensor is reduced, but the coil unit becomes more vulnerable to damage during assembly
Solution Approach 1:
The patent provides beforehand cushioning by introducing the support member that fits into the back yoke before the coil unit is installed. This support member acts as a protective cushion that prevents the flexible substrate coil unit from colliding with surrounding objects during assembly, thereby protecting the delicate coil unit while maintaining the reduced thickness design.
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 solution prevents damage to the coil unit during assembly and reduces the number of parts, enhancing measurement accuracy and reducing manufacturing costs.
Implementation Method 1
a magnetostrictive effect section whose magnetic permeability changes according to torque to be transmitted
Implementation Method 2
a detection coil that changes voltage in response to changes in the magnetic permeability of the magnetostrictive effect section
Implementation Method 3
a holder made of rubber or synthetic resin that covers an outer peripheral surface of the coil unit
Data Source
AI summary
The torque measuring device includes: a casing made of a magnetic metal; a rotating shaft rotatably arranged inside the casing and having a magnetostrictive effect section whose magnetic permeability changes according to torque to be transmitted; and a torque sensor arranged around the magnetostrictive effect section and supported by the casing, the torque sensor including a coil unit formed in a cylindrical shape using a flexible substrate having a detection coil that changes voltage in response to changes in the magnetic permeability of the magnetostrictive effect section, and a holder made of rubber or synthetic resin, covering an outer peripheral surface of the coil unit, and having a portion that protrudes from the coil unit on both sides in an axial direction; and the torque sensor supported by the casing with an outer peripheral surface of the holder fitted into an inner peripheral surface of the casing.