PPA Thermoplastic Housing for High Torque Screw Connections
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Solution Overview
Problem
Existing housing components for pressure medium-carrying devices face challenges in maintaining secure screw connections under extreme temperatures and vibration loads while being cost-effective, as materials like aluminum die-cast components are expensive to manufacture and have limitations in torque resistance.
Innovation Solution
The use of polyphthalamide (PPA) thermoplastic, particularly in the area of connection bores, provides enhanced material properties for high tightening and loosening torque, eliminating the need for metal threaded bushings and ensuring dimensional stability under stress and temperature variations, with properties such as high modulus of elasticity and resistance to creep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If aluminum die-cast components are used for housing components, then relatively high tightening and loosening torques can be achieved, but the manufacturing cost is relatively expensive
Solution Approach 1:
The patent changes the material parameter from aluminum die-cast to PPA thermoplastic, which provides comparable mechanical properties for screw connections while significantly reducing manufacturing cost through injection molding processes
Solution Approach 2:
The patent employs composite material construction by integrating metal threaded bushings into the PPA housing component, combining the advantages of both materials: PPA for cost-effective manufacturing and corrosion resistance, and metal bushings for high torque screw connections
2Reliability
If high tightening torque is applied to screw connections in housing components, then secure connections under extreme temperatures and vibration loads are achieved, but the material properties must be specifically optimized
Solution Approach 1:
The patent introduces metal threaded bushings as intermediary elements between the screw connection and the PPA housing component. These bushings bear the high tightening and loosening torques, protecting the PPA material from excessive stress while maintaining reliable screw connections under extreme conditions
Solution Approach 2:
The patent modifies the material parameters of the PPA thermoplastic through specific formulation and processing to achieve sufficient dimensional stability and mechanical properties, reducing but not eliminating the need for metal bushings in certain applications
Data Source
Figure 1
AI summary
The invention relates to a housing component (2) of a housing (10) of a vehicle device (1) conducting pressure medium, with at least one connecting bore (12, 14), which is provided with an internal thread, for the screwing-in of a connecting element provided with an external thread, for feeding the pressure medium to, and/or for removing same from, the device (1). The invention provides that the material of the housing component (2) is composed, at least in the region of the connecting bore (12, 14), of a thermoplastic in the form of PPA (polyphthalamide). This results in a release moment of the threaded connection after temperature ageing, said release moment being greater than 25% of the failure moment.