Torque Detection Device Resin Housing Integration
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Solution Overview
Problem
Existing torque detection devices face challenges in ensuring the magnetic shield is properly assembled, making it difficult to verify its presence, and they are prone to water ingress due to gaps between the unit and housing.
Innovation Solution
A torque detection device design featuring a magnetic flux collecting unit with an annular holder and magnetic shield, where the sensor housing is integrated with the magnetic flux collecting unit using resin, and through-holes in the holder allow verification of the magnetic shield's presence by checking if resin fills these holes during housing formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sensor housing is formed by supplying resin onto the outer periphery of the magnetic flux collecting unit to improve waterproofing, then the waterproof property is improved, but it becomes difficult to check whether the magnetic shield is assembled inside the device
Solution Approach 1:
The through-holes are formed in the holder before the resin is supplied to form the sensor housing. This preliminary action allows the magnetic shield's presence to be verified before the housing is sealed, enabling quality control inspection while maintaining the waterproof benefits of the integrated housing design
Solution Approach 2:
The magnetic shield is made of a magnetic material that can be detected through the resin housing. The presence of the magnetic shield can be verified by detecting its magnetic properties through the non-magnetic resin material, allowing quality control without disassembly
2Reliability
If the sensor housing and magnetic flux collecting unit are formed as an integrated structure, then waterproofing is improved, but the complexity of the manufacturing process increases
Solution Approach 1:
The sensor housing and magnetic flux collecting unit are combined into a single integrated structure by forming the housing directly onto the unit. This merging eliminates the need for separate assembly steps and sealing operations, reducing manufacturing complexity while improving waterproofing
Solution Approach 2:
The magnetic flux collecting unit is nested within the sensor housing, with the housing formed directly onto the unit's outer periphery. This nested configuration creates a seamless integrated structure that is both waterproof and manufacturable in a single process
3Ease of operation
If through-holes are formed in the holder to enable verification of magnetic shield assembly, then ease of quality control is improved, but water may enter through the holes if the shield is not properly assembled
Solution Approach 1:
The through-holes are formed in the holder before the resin housing is supplied. This allows quality control verification to be performed on the magnetic shield assembly before the housing is formed, ensuring proper assembly while maintaining waterproofing through the subsequent resin sealing
Solution Approach 2:
The resin housing acts as an intermediary that seals the through-holes after verification. The resin material fills and seals the holes, preventing water ingress while allowing the magnetic shield's presence to be verified through the non-magnetic resin
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 allows easy verification of the magnetic shield's assembly and enhances waterproofing by preventing resin from entering through-holes when the shield is correctly fitted, ensuring the device's integrity and functionality.
Implementation Method 1
a permanent magnet that is fixed to the first shaft member, and that forms a magnetic field around the first shaft member
Implementation Method 2
a magnetic yoke that is fixed to the second shaft member, that is arranged within the magnetic field formed by the permanent magnet, and that forms a magnetic circuit of which a magnetic flux density changes in response to a change in a position of the magnetic yoke relative to the permanent magnet due to torsion of the torsion bar
Implementation Method 3
a magnetic flux collecting ring that is fitted to an inner periphery of the holder so as not to cover the through-hole and that collects magnetic fluxes from the magnetic yoke
Implementation Method 4
a magnetic shield that is fitted to an outer periphery of the holder so as to cover the through-hole and that reduces influence of an external magnetic field on the magnetic circuit
Data Source
Figure 1
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Figure 3
AI summary
A torque detection device includes: a magnetic flux collecting unit (40) that includes an annular holder (50) formed by resin molding and having a through-hole (53A) that passes through the holder (50) in a radial direction, a first magnetic flux collecting ring (41) and a second magnetic flux collecting ring (42) that are fitted to an inner periphery of the holder (50) so as not to cover the through-hole (53A), and a magnetic shield that is fitted to an outer periphery of the holder (50) so as to cover the through-hole (53A); and a sensor housing (60) that is made of resin supplied onto an outer periphery of the magnetic flux collecting unit (40), and that is formed so as to be integrated with the magnetic flux collecting unit (40).