Torque Sensor Assembly Laser Welding Seal
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Solution Overview
Problem
Existing torque sensor assemblies in vehicle steering systems face challenges in maintaining a fluid-tight and secure enclosure to prevent contamination and ensure reliable operation, as they often rely on screws or other methods that may not provide a complete seal against water, dirt, and foreign bodies.
Innovation Solution
A torque sensor assembly with a housing and a cover secured by laser welding, where the cover is either formed separately and attached permanently or integrated during an overmolding process, incorporating flux concentrators and hall effect ICs within a carrier or directly in the housing, to create a fluid-tight seal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screws or other conventional fastening methods are used to secure the cover to the housing, then the assembly process is simpler and more accessible, but the seal against water, dirt, and foreign bodies is incomplete and unreliable
Solution Approach 1:
The patent replaces the mechanical screw-fastening system with a laser welding system. The cover and housing are equipped with laser welding profiles that enable direct welding without mechanical fasteners. This substitution eliminates the inability to achieve complete sealing while maintaining manufacturing feasibility through automated laser welding processes.
Solution Approach 2:
The patent changes the joining parameter from mechanical (screw torque, thread engagement) to thermal (laser welding temperature, melt pool dynamics). The laser welding process parameters are optimized to achieve complete penetration and fusion between the cover and housing, ensuring hermetic sealing while maintaining process control and manufacturability.
2Reliability
If the cover is formed separately and attached by conventional methods, then the manufacturing process is simpler, but the fluid-tight seal cannot be achieved
Solution Approach 1:
The patent replaces mechanical fastening with laser welding to join the separately formed cover to the housing. The laser welding profiles integrated into both components enable direct thermal fusion, achieving fluid-tight sealing without compromising the benefit of separate component manufacturing and assembly.
3Object-affected harmful factors
If conventional fastening methods are used, then the manufacturing process is more accessible and less expensive, but contamination from water, dirt, and foreign bodies cannot be prevented
Solution Approach 1:
The patent replaces mechanical fastening with laser welding to achieve hermetic sealing that prevents contamination. The laser welding process creates a continuous fused joint between the cover and housing, eliminating gaps and pathways for water, dirt, and foreign bodies to enter, while maintaining manufacturing feasibility through automated processes.
Solution Approach 2:
The patent utilizes the phase transition of materials during laser welding (solid to liquid and back to solid) to create a hermetic seal. The laser energy melts the welding profiles of the cover and housing, and upon cooling, forms a continuous fused joint that prevents contamination, combining effective protection with manufacturing capability.
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 laser welding and overmolding processes ensure a reliable, water-tight seal, reducing the risk of contamination and enhancing the durability and reliability of the torque sensor assembly in vehicle steering systems.
Implementation Method 1
the cover is secured to the housing by laser welding
Implementation Method 2
the cover may be formed as part of the housing during an overmolding process
Implementation Method 3
at least one flux concentrator and at least one hall effect IC disposed in the cavity of the housing
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An improved structure for a torque sensor assembly adapted for use in a vehicle steering system and method for producing the same. According to one embodiment, the torque sensor assembly includes a housing formed from a suitable material having a cavity; at least one flux concentrator and at least one hall effect IC disposed in the cavity of the housing; and a cover secured to the housing to close the cavity in the housing in a permanent and fluid-tight manner.