1Basic Knowledge of Seat System2Our goal: Explain the basic of seat design processExplain key issues that must be addressed during designGive you basic knowledge so you can:3ConceptsThree Dimensional Reference System is coordinate system to locate all components in a vehicleY coordinates represent the location of a point along the width of the vehicleX coordinates represent the location of a point along the vehicle lengthZ coordinates communicate height of a pointAxes define planes of reference that define grid lines4Three-Dimensional Reference System5Planes of Reference6Grid Lines and Work Lines WorkLinesGridLines7Functions of SeatSupport the occupantSupport is most basic functionPosition the occupantExtremely important to vehicle safetyProximity to controlsProvide comfort to the occupantFocus is on long-term comfortProtect the occupantPrevent the occupant from moving about inadvertently8Position and ComfortDriver position is defined by several measuresEyellipse represents field of visionEyellipse helps define seating reference point, or SgRPSgRP becomes basis for defining design H-PointDesign and actual H-Point are measured using two- and three-dimensional Oscar templates and manikins9Eyellipse and SgRP10H-Point11Measuring H-Point12Oscar Machine 13Worldwide Car ProductionIn this Lesson, we will discuss:Factors to consider when designing for a worldwide marketHow seat design is affected by the side of the vehicle on which the driver sitsOther influences on design:Size of vehiclesCustomer expectationsCultural differences Road, traffic and weather conditions14Designing for a Worldwide MarketDesign for local road conditions and the needs of the populationFocus of marketplace has broadened from North America and Europe to include:ChinaSouth AmericaSoutheast Asia15Left-hand Drive CountriesLeft-hand Drive CountriesLeft-hand Drive Countries2362.8 Total2362.8 Total16Right-hand Drive CountriesRight-hand Drive Right-hand Drive CountriesCountries2504.9.8 Total2504.9.8 Total17Left-hand and Right-hand DrivingLeft-Hand DriveRight-Hand Drive18Other Effects on DesignSome designs may have armrests only on one side for the driverDesign back frame to accept arm rest on either sideAllows the seat to become a driver or passenger seat depending on which side armrest is mountedDesign of bolsters, mainly on the cushion, must address ingress/egress considerationsIssues depend on which side the driver seat is mounted19Worldwide Automaker Market Share20Customer ExpectationsMost of the world prefers small vehiclesCostFuel pricesParking considerationsSmall car drivers expect same convenience and comfort as in larger vehiclesFront leg roomFoot and leg/knee clearancesPackaging for rear seat occupants21Cultural DifferencesIn many Asian countries, vehicle owner has a chauffeurB surface of the front seat back cant use a cheaper fabric to save costComfort considerations for rear seat become more importantTraffic jams may strand drivers in car seats for hoursIncorporating features to alleviate discomfort improves marketability22Seats in Small Vehicles Do Big ThingsAsian and Japanese designs incorporate many features into seats and interiorsSeats can be combined to make a bedSeat backs can be flipped from one side to the other to make a seat face the opposite waySeats can swivel to allow card playing or other gamesSecond row seats near the door may fold up or tuck away to improve ingress/egressStorage space may be above and below the seats23Road and Traffic ConditionsU.S. designs stay very close to federal guidelines20% safety factor European designs add extra strength to car and seatsHigher road speeds dictate safety factor of 200% to 300%May not be appropriate for Asian countries, where road speeds are lower24Weather Conditions VaryMost Asian countries have extreme weather conditionsFlooding, heavy rain and dirt/dust are commonOwners install extra covers to protect seatsCertain design features may not be desirableExpensive cover materialsHigh contour or styleHigh production tolerances25Seat System PhilosophyDesign For High Volume ProductionJIT ManufacturingSeat engineers and SDT members must keep two things in mind:26Design for High Volume ProductionPhilosophy for design differs from very low volume and very high volumesJCIs range of annual volume for any one seat design is from a minimum of 60,000 to no real maximumException: JCI produces seats for the ViperVolumes as high as 600,000 have been realized on the same design27JIT ManufacturingJIT influences on product design include:No inspection - fixtures used as gaugesDesign incorporates error-proofingNo more than 4 hours of inventoryDesign should allow assembly in 15 - 30 second sequencesAll operations must be designed to flow in one directionOperation specifications should have high reliability and quality28Installing Seats into the VehicleSeat must be designed to accept handling required to install in the vehicleSeat is positioned at the right place in the vehicle at right time in assembly processMay be positioned manually or by robotAll power connections for the seat are availableSeat system engineer must know how the seat the seat will be installed (manual or robot)Seat must accommodate unexpected handling situations 29Designing for SafetyConsider the safety of everyone involvedOccupantManufacturing/Assembly personnelEnd-userDocumentation can become evidence in courtSafety is an attitude Design-in not inspect-out later in processNo separate tests for designed-in safetyAvoids “Band-Aid” production fixes30Typical Sources of NoiseMetal to metal contactsBad weld joints, latches, pivot points, spring hooks, etc.Foam to metal contactsFoam to cover materialsLoose/binding parts in recliners, adjusters, latches, etc.Cover to cover materialLoose or rattling head restraint 31More Typical Sources of NoisePlastic parts to cover and/or metalLoose boltsInterference to other parts in the vehicleCup-holder partsArmrest parts in up/down positionSuspension and lumbar partsPower track motorsElectro-mechanical noisesExcessive chuck/play in mechanisms32Seat Trim Outline (STO) Drawing331/4 Scale and 1/5 Scale Drawing34Complexity Chart35Determine Function and UsagePLUS Phase 1 Program Definition captures customer requirements for featuresComplete Bill of Materials prepared for product being quotedCustomer input allows seat engineer to determine how seat is expected to functionBecomes the basis for seat designSeats must match vehicle and needs of targeted consumer group36Defining RequirementsQuantifies functions and usage decisionsSeat back travelAdjuster operating forcesCustomer inputs in Phase 1 documentsSome requirements established based on initial analysis of function of seat systemDocumenting requirements critical Select applicable and appropriate requirementsWork to meet future requirements37H-Point and Comfort ControlOne of four functions of seat system is to provide comfort to the occupantH-Point, comfort and appearance are most important to the customerMost engineering efforts concentrate on these itemsA good design is always a compromise between these demandsEnter prototype builds with solid EXPECTATIONS of performanceAnalysis replaces “find-and-fix”38Significance of H-PointH-Point is one of several parameters that define manikins position in seatH-Point is in part determined by “eyellipse”Failing to meet H-Point means other controls may not meet government requirements Always remember balance and interplay ofH-PointComfortAppearance39Torso Angle and A SurfaceTORSO ANGLE40Front Seat Cushion Design Factors41Seat Back Design Factors 42Metal and MechanismsChoice dictated by the customerVarious options and features captured in the programs complexity chartLesson Three discussed how to package metalReclinersAdjustersBack and cushion framesThis lesson discusses the function of these components43FramesFrames give seat a sense of stabilitySkeleton on which the foam and trim restFrames are key structural parts Backframe helps carry load into reclinerCushion frame is not in load pathConstruction and materials chosen to meet performance requirementsDetails are covered in Seat System Design Two44FramesPackaging of frames can be iterativePackage must accommodate frames with enough strength to meet requirements but also must meet comfort and clearances45ReclinersCritical to seat system performanceRecliner must be designed to withstand loads applied during typical and atypical operations Transfer loads directly to adjusters and ultimately to vehicle floorTypes include single-sided and dual-sidedManual and automatic variantsClassifications include linear and gearedFunction was described in Introduction to Seats46Classes of ReclinersLinearAdapted 10 years ago from the aircraft industryContinuous engagementDiscrete engagementRotaryContinuously engaged or rotary type can be “cranked” to position back angle to desired anglePredominantly EuropeanPawl and sector releases and moves seat back to desired positionPredominantly in North America47Dual Sided Recliner48Single-sided vs. Dual-sidedDecide to use either single-sided or dual-sided recliners during layout and packagingDual-sided recliners attach to each side of backframeSingle-sided recliners have a single switch and a slave hinge or pivot on the other sideLoad path is different depending on recliner chosenLoad travels through the reclinerDual-sided recliners split load equally on both sidesSingle-sided recliners pass loads only through recliner side49AdvantagesqReduction of part count, since many components can be symmetrical between driver and passenger seatsqBack frame is lighter since loads are shared. Strong torsional member is not required.qBack frame is common between driver and passenger seatsqFoam pads and even trim covers and plastic panels can be common between driver and passenger seatsqMore torsional rigidity is achievedqIt is easier to defend the OEMs position in a court of law from a due care point of view. Many OEMs, especially the Japanese, have taken this position.50DisadvantagesqCost and weight of an extra recliner, although partially or wholly offset by the reduction in the back frame cost and weight. Also offset by reduction in number of parts.qPackaging a dual sided frame is often more difficultqSynchronization of the two recliners is difficult in the assembly of the seat. (Many times dual recliners are welded to the backframe)qShipment and transportation of welded sub-assemblies can create other issuesqWith two recliners, operating efforts generally are higher qFor dual rotary recliners there is a higher potential for seat judder or roughness upon operation51Adjuster SelectionCan be chosen after it is understood how backframe load gets carried to adjusterUsed to only handle seat loadsMust withstand much more load with traveling inboard buckles (TIB)JCI is not responsible for seat belt buckle, butJCI is responsible for interfaces between seat and belt buckleStudies must be done to determine proper location and attachment method to ensure proper function52Adjuster Construction53Adjuster LatchingMost are lever-actuatedLever is located under the front of the seatLever releases locking mechanisms to allow forward or rearward movementDual sided releases connected by “towel bar” handleSingle-side release connects latches with tie wire or linkageSynchronizing latches is criticalLatches should engage as close to simultaneously as possible54Gravity Balancing SpringsAdjuster angle specified by customerNo reason to change without compelling reasonIf adjuster angle exceeds 6 degrees, then review designGravity balancing springs help in moving seat forward if angle is too steepAssists forward movementHinders backward movementCreates safety issue for assemblyShip the adjuster with the spring unloaded55FMVSS 201 TestingDemonstrates ability of complete seat to provide head protection for rear seat occupants in frontal impactsApplies to all seats except:RearmostSide facingBack-to-backFolding auxiliary jumpTemporaryqRear seatH-point(along line)Figure 1: FMVSS 201 Impact Angle Diagram56FMVSS 202 TestingReduce frequency and severity of neck injury (whiplash) in rear-end collisionsApplies to all seats with head restraintsMoment applied to seat back to establish displaced torso lineSame moment applied to head restraintUltimate load of 200 lbs. appliedDisplaced torso lineHead Form Initial PositionHead Form Final PositionTotal H/R Displacement3300 in-lbs.57FMVSS 207 TestingDemonstrates that the seat vehicle attachment assemblies can sustain forward and rearward forces from vehicle impactsApplies to all occupant seatsLoad applied is 20 times weight of complete seat forward and rearwardApplied LoadDistribution BarsC.G. BarDistribution BarsC.G. BarApplied Load58FMVSS 210 TestingEstablishes requirements for seat belt anchorages and reduced likelihood of failure in frontal impactApplies to single and multi-occupant seats with seat belts attachedUsually combined with FMVSS 207 forward anchorage test(5-15)Shoulder Belt Load(5-15)Lap Belt LoadC.G. of Seat LoadC.G. BarFoam PadLap BlockBodyBlockFigure 9: FMVSS 210 Set-up for Seat Belt Anchorage Test59FMVSS 225 TestingEstablishes requirements for child restraint anchorage systems to ensure proper location and strengthApplies to all child restraint systems and child restraint anchorage systems LATCH (Lower Anchors and Tethers for Children)60Worldwide RegulationsUnited Nations-Economic Community of Europe (ECE)European Community (EEC)Canadian Motor Vehicle Safety Standards (Canada) (CMVSS)Australian Design Rules (Australia) (ADR)Safety Regulations for Road Vehicles (Japan) (TRIAS)Guo Biao (China) 61Homologation vs Self-CertificationHomologation is certification by third party chosen by government that items pass tests before government issues its approvalStandard for products used in EuropeRequires more extensive preparationsSelf-certification is certification by manufacturer that items pass tests before government issues its approvalStandard in North America