Sensor Overmolding Cylindrical Volume Equalization
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Solution Overview
Problem
The existing methods for overmolding measurement sensors in motor vehicles are complex, time-consuming, and expensive, often resulting in material shrinkage and microcracks due to uneven thermoplastic material volumes, which compromises the sealing integrity of the sensors.
Innovation Solution
A method involving a cylindrical molding process with equalized volumes for thermoplastic material injection, using a first and second cylindrical portion with a circular cross section, and sealing means made from the second portion to prevent material shrinkage and ensure homogeneous overmolding thickness, allowing for the production of various sensor types with a single tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional overmolding methods are used with varying thermoplastic material volumes, then the sensor can be manufactured, but material shrinkage and microcracks occur compromising sealing integrity
Solution Approach 1:
The invention changes the geometric parameters of the molding cavity by introducing a compensation element that adjusts the volume of thermoplastic material required for different zones. This ensures uniform material distribution and eliminates shrinkage-induced microcracks in the sealing fins, thereby improving sealing integrity without compromising manufacturing precision.
Solution Approach 2:
The compensation element is pre-installed in the molding cavity before injection to preemptively compensate for volume differences. This preliminary action prevents material shrinkage and microcrack formation during the cooling phase, ensuring high-quality sealing fins from the outset.
2Manufacturing precision
If separate molds are created for each sensor type, then manufacturing precision can be maintained, but the process becomes complex, time-consuming and expensive
Solution Approach 1:
The invention creates a universal molding cavity design that can accommodate different sensor types through the use of adjustable or interchangeable compensation elements. This single mold design maintains manufacturing precision across various sensor configurations while eliminating the need for separate molds for each sensor type, thereby reducing complexity and production costs.
Solution Approach 2:
The molding cavity is segmented into standardized zones with interchangeable compensation elements that can be selected based on the specific sensor type. This segmentation allows the same base mold to be used for multiple sensor variants while maintaining precision, reducing the overall complexity of mold management.
3Reliability
If sealing fins are placed between high and low volume zones, then sealing coverage is improved, but material shrinkage generates microcracks reducing seal tightness
Solution Approach 1:
The invention modifies the material volume parameters in high-volume zones by introducing compensation elements that reduce the excess material. This ensures that sealing fins located in these zones receive uniform material distribution, preventing shrinkage-induced microcracks while maintaining comprehensive sealing coverage.
Solution Approach 2:
The compensation element is pre-positioned in high-volume zones before injection to preemptively balance material distribution. This preliminary action prevents microcrack formation in sealing fins during cooling, ensuring both integrity and seal tightness are maintained.
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 approach simplifies and cost-reduces the production of measurement sensors by preventing material shrinkage and microcracks, ensuring reliable sealing and reducing the need for complex mold designs, while maintaining reduced bulk and homogeneous overmolding thicknesses.
Implementation Method 1
after the injection of thermoplastic material and when the latter cools, the thermoplastic material situated in the high-volume zones shrinks to a greater extent
Data Source
AI summary
A method for manufacturing a measurement sensor for a motor vehicle is disclosed. The vehicle has a body and an electronic measurement module mounted in the body. The method includes molding the body of the sensor so as to define, in one and the same material, a base for fastening the sensor, an element for receiving the electronic measurement module, and a seal. The element delineates a space for receiving the electronic measurement module and includes a first cylindrical portion with a circular cross section and a second cylindrical portion with a circular cross section. The diameter of the second cylindrical portion is smaller than the diameter of the first cylindrical portion. The method further includes mounting the electronic measurement module in the reception space, and overmolding the element for receiving the electronic measurement module.