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© 2001 MIT PSDAM AND PERG LABS NEAR KINEMATIC CONSTRAINT
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© 2001 MIT PSDAM AND PERG LABS Quasi-Kinematic (QKC) alignment QKC characteristics: Arc contact Submicron repeatability Stiff, sealing contact Less expensive than KCs Easier to make than KCs QKC Function: Ball & groove comply Burnish surface irregularities Elastic recovery restores gap Groove Seat Side Reliefs Spherical Protrusion F or initial = 0 final Distance along Cone Face, [inches] Feature Height, mils
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© 2001 MIT PSDAM AND PERG LABS PAIRS OF QKC ELEMENTS ASSEMBLED JOINTTYPE 2 GROOVE MFG. CASTFORM TOOLFINISHED += + + OR Details of QKC element geometry
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© 2001 MIT PSDAM AND PERG LABS Which variation of QKC to use Design ADesign B In Design A, Peg deforms on edge -> reduced repeatability + + OR
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© 2001 MIT PSDAM AND PERG LABS x y Contact Point Ball Groove Surface Peg Surface Relief Cone Seat QKC methods vs kinematic method Relief Components and Definitions Force Diagrams
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© 2001 MIT PSDAM AND PERG LABS Resultant Forces [n i & Fi] Applied Loads [Fp & Mp] Deflections -> r Relative Error Geometry Material Modeling QKC stiffness QKC Model Geometry Material Displacements Contact Stiffness f n ( n ) Force/Torque Stiffness
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© 2001 MIT PSDAM AND PERG LABS MECHANICS: Use Rotating Coordinate System Assume Sinusoidal Normal Distance of Approach Obtain Contact Stress Profile as Function of Above Integrate Stress Profile in Rotating CS thru contact Rotating CS n l s ^ ^ ^ QKC contact mechanics k n l i ^ RcRc ^ ^ ^
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© 2001 MIT PSDAM AND PERG LABS 10 m 5 m 0 m Coupling + Others Process Rough Error Budget Characteristics: Ford 2.5 & 3.0 L V6 > 300,000 Units / Year Cycle Time: < 30 s Example: Duratec TM assembly
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© 2001 MIT PSDAM AND PERG LABS C B Halves Block Bedplate Assembly Bolts BlockBedplate r a JRJR ee JLJL Block Bore Bedplate Bore C L C L e MAX = 5 microns ERROR ASSEMBLY COMPONENTS Example: Assembly of Duratec TM block & bedplate
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© 2001 MIT PSDAM AND PERG LABS Bedplate Main Bearing Half Block Main Bearing Half Crank Shaft Journal Block Main Bearing Halves Bedplate Crank Shaft Piston Bearing assemblies in engines
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© 2001 MIT PSDAM AND PERG LABS Detail of Duratec TM QKC element placement
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© 2001 MIT PSDAM AND PERG LABS MANUFACTURING: DESIGN: Results of Duratec TM QKC Research
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© 2001 MIT PSDAM AND PERG LABS Bedplate 2 nd Block Fixture J L Cap Probe J R Cap Probe 1 st Block Fixture Bedplate Fixture CMM Head Axial Cap Probe Axial Sensitive 9 ( Range / 2 )| AVG = 0.65 m ( Range / 2 ) = 1.35 m Engine assembly performance
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