Cylindrical Current Sense Resistor with Hollow Termination
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Solution Overview
Problem
Traditional flat resistors used in automotive applications for current sensing are not space-efficient and limit the placement of support electronics, posing risks to vital vehicle functions due to potential electrical system issues.
Innovation Solution
A cylindrical resistor with a hollow termination and magnetic pulse welding method is developed, allowing for a more compact design that can be integrated into a cable assembly at any position, with adjustable resistance and sense leads for efficient current sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional flat resistor is used for current sensing, then the resistor can be manufactured with simple welding or brazing, but the resistor occupies excessive space and limits the placement of support electronics
Solution Approach 1:
The patent applies spheroidality by transitioning from a traditional flat resistor geometry to a cylindrical resistor geometry. The cylindrical shape is formed by rolling a flat resistive element into a tube and joining the ends, creating a curved three-dimensional structure that reduces the overall volume occupied by the resistor while maintaining its electrical functionality. This curved geometry allows for more efficient space utilization in the cable assembly.
Solution Approach 2:
The patent employs dimensionality change by transforming the two-dimensional flat resistor into a three-dimensional cylindrical structure. By rolling the flat resistive element into a tube and adding depth through the cylindrical form, the resistor utilizes the third dimension to reduce its footprint in the planar direction, thereby freeing up space for support electronics while preserving the electrical path.
2Adaptability or versatility
If a flat resistor is used, then the structure is simple, but the placement flexibility in cable assemblies is limited
Solution Approach 1:
The cylindrical curved structure provides rotational symmetry and uniform cross-section along its length, enabling the resistor to be oriented in any direction and integrated at various positions within the cable assembly. This geometric form factor offers superior adaptability compared to flat resistors, allowing installation in confined spaces and integration with support electronics without rigid orientation constraints.
Solution Approach 2:
The cylindrical resistor design serves multiple functions: it acts as the current-sensing resistive element, provides structural support within the cable assembly, and creates a compact form that facilitates integration with support electronics. The hollow cylindrical structure can also accommodate additional components or wiring within its interior space, enhancing the overall versatility of the assembly.
3Adaptability or versatility
If traditional welding or brazing is used to attach terminations, then the process is straightforward, but the resistor cannot be easily integrated at any position along the cable
Solution Approach 1:
The resistor is segmented into distinct functional zones: the hollow cylindrical resistive body and separate termination components. This segmentation allows the resistive element to be manufactured independently with precise resistance characteristics, while terminations can be separately prepared and attached at various positions along the cable length, providing integration flexibility without compromising the resistive element's integrity.
Solution Approach 2:
The cylindrical geometry with uniform cross-section enables the resistor to be positioned at any location along the cable without requiring specific orientation or additional structural support. The symmetrical form factor allows for versatile integration points and simplifies the attachment process compared to asymmetric flat resistors that require precise positioning and alignment.
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 cylindrical resistor design enhances space efficiency, flexibility in placement, and effective current sensing, ensuring the reliability of vital vehicle systems by providing a robust and adaptable solution for automotive applications.
Implementation Method 1
magnetic pulse welding a resistive element between the first tube and the second tube to thereby provide a substantially cylindrical resistor
Data Source
Figure 1~2
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Figure 5~7
AI summary
A resistor (12) includes a substantially cylindrical resistive element having a resistance of less than about 1 m?, a substantially cylindrical first, termination (14) electrically connected to the resistive element and a second termination (16) electrically connected to the resistive element. The substantially cylindrical first termination is hollow to allow for accepting a connection such as from a battery cable (32). In addition there may be sense leads (22, 24) present on the resistor. A method of forming a substantially cylindrical resistor includes forming a hollow cylindrical resistor body by rolling a flat sheet comprising a resistive element and a first termination and a second termination joined on opposite ends of the resistive element.