Vehicle Level Sensor Rotor Positioning via Injection Molding
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Solution Overview
Problem
Existing level sensors for motor vehicles face challenges in precise positioning of the rotor relative to the housing due to play between parts, leading to complex constructions and high production costs.
Innovation Solution
A level sensor design featuring a plastic housing with a cylindrical section and a plastic rotor, where the rotor is guided and locked within the cylinder using injection molding, eliminating the need for additional fasteners and minimizing play through annular latching grooves, PTFE lubricant, and surface coatings to reduce friction and ensure precise positioning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If traditional mechanical fastening methods are used to secure the rotor to the housing, then the rotor positioning stability is improved, but the device complexity and production cost increase due to additional fasteners and complex assembly
Solution Approach 1:
The rotor is integrated directly into the housing structure through injection molding, merging two previously separate components (rotor and housing) into a single molded part. This eliminates the need for separate fasteners and complex mechanical fastening mechanisms, reducing assembly complexity while maintaining positioning stability through the molded-in-place connection
Solution Approach 2:
Traditional mechanical fastening systems (screws, clips, or interference fits) are replaced with an injection molding process that creates a permanent mechanical bond between the rotor and housing. The molding process itself provides the securing function that previously required separate mechanical fasteners, simplifying the overall device structure
2Reliability
If traditional sealing methods with covers and openings are used, then the housing sealing is achieved, but the manufacturing cost and assembly complexity increase due to additional sealing components and procedures
Solution Approach 1:
The sealing function is merged into the housing structure itself through integrated sealing elements molded directly into the housing. This eliminates the need for separate sealing components such as gaskets, O-rings, or cover assemblies, reducing both manufacturing cost and assembly complexity while maintaining reliable sealing
Solution Approach 2:
The patent utilizes flexible sealing elements that are molded into the housing structure, allowing these thin film-like sealing features to conform to mating surfaces and provide effective sealing without requiring rigid, complex sealing mechanisms. The flexibility of the molded sealing elements enables reliable sealing while keeping the design simple
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 allows for easy and cost-effective production of level sensors with precise rotor positioning, reducing manufacturing complexity and play between parts, thereby enhancing the accuracy and reliability of the sensor's operation.
Implementation Method 1
The rotor is made of a plastic with a proportion of embedded lubricant; this lubricant is a plastic with a particularly low coefficient of friction such as PTFE.
Implementation Method 2
an annular latching groove is embedded on the outside of the cylinder. In conjunction with a corresponding locking lug on the rotor, this is guided securely for rotary movements and at the same time fixed and braced in a predetermined position in the cylinder.
Data Source
Figure 1
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Figure 3
AI summary
The invention relates to a level sensor for a motor vehicle, comprising a housing (1), a rotor (2) rotatably mounted on the housing (1), a printed circuit board (3) which is enclosed by the housing (1) and comprises at least one stator, and a connector (4). The level sensor is intended to be improved in such a manner that the rotor (2) can be easily mounted on the housing (1) and there is virtually no play in this case, with the result that a position of the stator relative to a rotor structure (9) is exactly complied with to the greatest possible extent. Overall, the sensor is intended to be inexpensive to produce. This is achieved by virtue of the fact that the housing (1) has a cylinder (6) which is formed on the outside and has a circular cross section, the rotor (2), with the exception of a rotor structure (9), is produced from plastic, and the rotor (2) is guided in the cylinder (6) and is latched to the latter.