Sphere-To-Cone Mating – New Solution to Improve Brake Tube Connector Sealing Robustness

Recently invented solutions (Canadian Patent 2593305 and United States Patent Applications 20090015008 and 20070194567) incorporate sphere-to-cone type of the interaction between sealing surfaces in a brake tube connector. An interaction of sphere-to-cone type has numerous advantages over one with a cone-to-cone type which is currently utilized in conventional automotive brake tube connectors. Incorporation of a sphere-to-cone interaction between the sealing surfaces dramatically improves connector's sealing robustness. Sphere-to-cone based connectors are resilient to the tube and seat axes misalignment. Correspondingly, sphere-to-cone based connectors have less variation of the securing torque and virtually no propensity to locked misalignment occurrence. The article analyzes another fundamental advantage of a sphere-to-cone mating over the conventional cone-to-cone one. The analysis reveals that sphere-to-cone type of interaction demonstrates approximately one order of magnitude (10 times) less sensitivity to common dimensional variation. A Robust Design approach has been utilized for sealing capability analysis and comparison. The transfer functions with respect to the sealing capability of both current cone-to-cone based connectors and new sphere-to-cone based connectors have been obtained and compared. The comparison suggests that for the same degree of sealing capability the dimensional and quality controls would be significantly simplified in case of sphere-to-cone based connectors manufacturing.