NEAR KINEMATIC CONSTRAINT 2001 MIT PSDAM AND PERG

NEAR KINEMATIC CONSTRAINT © 2001 MIT PSDAM AND PERG LABS

Quasi-Kinematic (QKC) alignment QKC characteristics: ¤ ¤ ¤ Spherical Protrusion Arc contact Submicron repeatability Stiff, sealing contact Less expensive than KCs Easier to make than KCs Groove Seat Feature Height, mils Side Reliefs QKC Function: ¤ ¤ ¤ Ball & groove comply Burnish surface irregularities Elastic recovery restores gap F or D Distance along Cone Face, [inches] dinitial © 2001 MIT PSDAM AND PERG LABS d =0 dfinal

Details of QKC element geometry PAIRS OF QKC ELEMENTS + + OR TYPE 2 GROOVE MFG. ASSEMBLED JOINT BOLT + CAST = FORM TOOL © 2001 MIT PSDAM AND PERG LABS BLOCK FINISHED BEDPLATE PEG

Which variation of QKC to use Design A Design B + OR + In Design A, Peg deforms on edge -> reduced repeatability © 2001 MIT PSDAM AND PERG LABS

QKC methods vs kinematic method Components and Definitions y x Relief Cone Seat Ball Groove Surface Peg Surface Force Diagrams © 2001 MIT PSDAM AND PERG LABS Contact Point

Modeling QKC stiffness Applied Loads [Fp & Mp] Geometry Material Resultant Forces [ni & Fi] Deflections d -> Dr Relative Error Material Contact Stiffness fn(dn) QKC Model Force/Torque Geometry Displacements Stiffness © 2001 MIT PSDAM AND PERG LABS

QKC contact mechanics ^l n^ MECHANICS: • Use Rotating Coordinate System ^ s • Assume Sinusoidal Normal Distance of Approach • Obtain Contact Stress Profile as Function of Above • Integrate Stress Profile in Rotating CS thru contact ^ k ^ n ^l Rc ^ i © 2001 MIT PSDAM AND PERG LABS Rotating CS

Example: Duratec. TM assembly Characteristics: • Ford 2. 5 & 3. 0 L V 6 10 mm • > 300, 000 Units / Year • Cycle Time: < 30 s Coupling + Others Process 5 mm 0 mm Rough Error Budget © 2001 MIT PSDAM AND PERG LABS

Example: Assembly of Duratec. TM block & bedplate COMPONENTS Block Bedplate ERROR ASSEMBLY de MAX = 5 microns Assembly Bolts de Bedplate C B Halves JL Block JR r a © 2001 MIT PSDAM AND PERG LABS Block Bore CL Bedplate Bore CL

Bearing assemblies in engines Block Crank Shaft Journal Block Main Bearing Half Piston Crank Shaft Bedplate Main Bearing Halves © 2001 MIT PSDAM AND PERG LABS Bedplate Main Bearing Half

Detail of Duratec. TM QKC element placement © 2001 MIT PSDAM AND PERG LABS

Results of Duratec. TM QKC Research MANUFACTURING: DESIGN: © 2001 MIT PSDAM AND PERG LABS

Engine assembly performance Axial JL Cap Probe 1 st Block Fixture Sensitive CMM Head Bedplate Fixture Bedplate JR Cap Probe Axial Cap Probe 2 nd Block Fixture (Range/2)|AVG = 0. 65 mm © 2001 MIT PSDAM AND PERG LABS (Range/2) = 1. 35 mm 9