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Basic Knowledge of Seat System,Our goal:,Explain the basic of seat design process Explain key issues that must be addressed during design,Give you basic knowledge so you can:,Concepts,Three Dimensional Reference System is coordinate system to locate all components in a vehicle Y coordinates represent the location of a point along the width of the vehicle X coordinates represent the location of a point along the vehicle length Z coordinates communicate height of a point Axes define planes of reference that define grid lines,Three-Dimensional Reference System,Planes of Reference,Grid Lines and Work Lines,Functions of Seat,Support the occupant Support is most basic function Position the occupant Extremely important to vehicle safety Proximity to controls Provide comfort to the occupant Focus is on long-term comfort Protect the occupant Prevent the occupant from moving about inadvertently,Position and Comfort,Driver position is defined by several measures Eyellipse represents field of vision Eyellipse helps define seating reference point, or SgRP SgRP becomes basis for defining design H-Point Design and actual H-Point are measured using two- and three-dimensional Oscar templates and manikins,Eyellipse and SgRP,H-Point,Measuring H-Point,Oscar Machine,Worldwide Car Production,In this Lesson, we will discuss: Factors to consider when designing for a worldwide market How seat design is affected by the side of the vehicle on which the driver sits Other influences on design: Size of vehicles Customer expectations Cultural differences Road, traffic and weather conditions,Designing for a Worldwide Market,Design for local road conditions and the needs of the population Focus of marketplace has broadened from North America and Europe to include: China South America Southeast Asia,Left-hand Drive Countries,Left-hand Drive Countries 2362.8 Total,Right-hand Drive Countries,Right-hand Drive Countries 2504.9.8 Total,Left-hand and Right-hand Driving,Other Effects on Design,Some designs may have armrests only on one side for the driver Design back frame to accept arm rest on either side Allows the seat to become a driver or passenger seat depending on which side armrest is mounted Design of bolsters, mainly on the cushion, must address ingress/egress considerations Issues depend on which side the driver seat is mounted,Worldwide Automaker Market Share,Customer Expectations,Most of the world prefers small vehicles Cost Fuel prices Parking considerations Small car drivers expect same convenience and comfort as in larger vehicles Front leg room Foot and leg/knee clearances Packaging for rear seat occupants,Cultural Differences,In many Asian countries, vehicle owner has a chauffeur B surface of the front seat back cant use a cheaper fabric to save cost Comfort considerations for rear seat become more important Traffic jams may strand drivers in car seats for hours Incorporating features to alleviate discomfort improves marketability,Seats in Small Vehicles Do Big Things,Asian and Japanese designs incorporate many features into seats and interiors Seats can be combined to make a bed Seat backs can be flipped from one side to the other to make a seat face the opposite way Seats can swivel to allow card playing or other games Second row seats near the door may fold up or tuck away to improve ingress/egress Storage space may be above and below the seats,Road and Traffic Conditions,U.S. designs stay very close to federal guidelines 20% safety factor European designs add extra strength to car and seats Higher road speeds dictate safety factor of 200% to 300% May not be appropriate for Asian countries, where road speeds are lower,Weather Conditions Vary,Most Asian countries have extreme weather conditions Flooding, heavy rain and dirt/dust are common Owners install extra covers to protect seats Certain design features may not be desirable Expensive cover materials High contour or style High production tolerances,Seat System Philosophy,Design For High Volume Production JIT Manufacturing,Seat engineers and SDT members must keep two things in mind:,Design for High Volume Production,Philosophy for design differs from very low volume and very high volumes JCIs range of annual volume for any one seat design is from a minimum of 60,000 to no real maximum Exception: JCI produces seats for the Viper Volumes as high as 600,000 have been realized on the same design,JIT Manufacturing,JIT influences on product design include: No inspection - fixtures used as gauges Design incorporates error-proofing No more than 4 hours of inventory Design should allow assembly in 15 - 30 second sequences All operations must be designed to flow in one direction Operation specifications should have high reliability and quality,Installing Seats into the Vehicle,Seat must be designed to accept handling required to install in the vehicle Seat is positioned at the right place in the vehicle at right time in assembly process May be positioned manually or by robot All power connections for the seat are available Seat system engineer must know how the seat the seat will be installed (manual or robot) Seat must accommodate unexpected handling situations,Designing for Safety,Consider the safety of everyone involved Occupant Manufacturing/Assembly personnel End-user Documentation can become evidence in court Safety is an attitude Design-in not inspect-out later in process No separate tests for designed-in safety Avoids “Band-Aid” production fixes,Typical Sources of Noise,Metal to metal contacts Bad weld joints, latches, pivot points, spring hooks, etc. Foam to metal contacts Foam to cover materials Loose/binding parts in recliners, adjusters, latches, etc. Cover to cover material Loose or rattling head restraint,More Typical Sources of Noise,Plastic parts to cover and/or metal Loose bolts Interference to other parts in the vehicle Cup-holder parts Armrest parts in up/down position Suspension and lumbar parts Power track motors Electro-mechanical noises Excessive chuck/play in mechanisms,Seat Trim Outline (STO) Drawing,1/4 Scale and 1/5 Scale Drawing,Complexity Chart,Determine Function and Usage,PLUS Phase 1 Program Definition captures customer requirements for features Complete Bill of Materials prepared for product being quoted Customer input allows seat engineer to determine how seat is expected to function Becomes the basis for seat design Seats must match vehicle and needs of targeted consumer group,Defining Requirements,Quantifies functions and usage decisions Seat back travel Adjuster operating forces Customer inputs in Phase 1 documents Some requirements established based on initial analysis of function of seat system Documenting requirements critical Select applicable and appropriate requirements Work to meet future requirements,H-Point and Comfort Control,One of four functions of seat system is to provide comfort to the occupant H-Point, comfort and appearance are most important to the customer Most engineering efforts concentrate on these items A good design is always a compromise between these demands Enter prototype builds with solid EXPECTATIONS of performance Analysis replaces “find-and-fix”,Significance of H-Point,H-Point is one of several parameters that define manikins position in seat H-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 of H-Point Comfort Appearance,Torso Angle and A Surface,TORSO ANGLE,Front Seat Cushion Design Factors,Seat Back Design Factors,Metal and Mechanisms,Choice dictated by the customer Various options and features captured in the programs complexity chart Lesson Three discussed how to package metal Recliners Adjusters Back and cushion frames This lesson discusses the function of these components,Frames,Frames give seat a sense of stability Skeleton on which the foam and trim rest Frames are key structural parts Backframe helps carry load into recliner Cushion frame is not in load path Construction and materials chosen to meet performance requirements Details are covered in Seat System Design Two,Frames,Packaging of frames can be iterative Package must accommodate frames with enough strength to meet requirements but also must meet comfort and clearances,Recliners,Critical to seat system performance Recliner must be designed to withstand loads applied during typical and atypical operations Transfer loads directly to adjusters and ultimately to vehicle floor Types include single-sided and dual-sided Manual and automatic variants Classifications include linear and geared Function was described in Introduction to Seats,Classes of Recliners,Linear Adapted 10 years ago from the aircraft industry Continuous engagement Discrete engagement Rotary Continuously engaged or rotary type can be “cranked” to position back angle to desired angle Predominantly European Pawl and sector releases and moves seat back to desired position Predominantly in North America,Dual Sided Recliner,Single-sided vs. Dual-sided,Decide to use either single-sided or dual-sided recliners during layout and packaging Dual-sided recliners attach to each side of backframe Single-sided recliners have a single switch and a slave hinge or pivot on the other side Load path is different depending on recliner chosen Load travels through the recliner Dual-sided recliners split load equally on both sides Single-sided recliners pass loads only through recliner side,Advantages,Reduction of part count, since many components can be symmetrical between driver and passenger seats Back frame is lighter since loads are shared. Strong torsional member is not required. Back frame is common between driver and passenger seats Foam pads and even trim covers and plastic panels can be common between driver and passenger seats More torsional rigidity is achieved It 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.,Disadvantages,Cost 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. Packaging a dual sided frame is often more difficult Synchronization of the two recliners is difficult in the assembly of the seat. (Many times dual recliners are welded to the backframe) Shipment and transportation of welded sub-assemblies can create other issues With two recliners, operating efforts generally are higher For dual rotary recliners there is a higher potential for seat judder or roughness upon operation,Adjuster Selection,Can be chosen after it is understood how backframe load gets carried to adjuster Used to only handle seat loads Must withstand much more load with traveling inboard buckles (TIB) JCI is not responsible for seat belt buckle, but JCI is responsible for interfaces between seat and belt buckle Studies must be done to determine proper location and attachment method to ensure proper function,Adjuster Construction,Adjuster Latching,Most are lever-actuated Lever is located under the front of the seat Lever releases locking mechanisms to allow forward or rearward movement Dual sided releases connected by “towel bar” handle Single-side release connects latches with tie wire or linkage Synchronizing latches is critical Latches should engage as close to simultaneously as possible,Gravity Balancing Springs,Adjuster angle specified by customer No reason to change without compelling reason If adjuster angle exceeds 6 degrees, then review design Gravity balancing springs help in moving seat forward if angle is too steep Assists forward movement Hinders backward movement Creates safety issue for assembly Ship the adjuster with the spring unloaded,FMVSS 201 Testing,Demonstrates ability of complete seat to provide head protection for rear seat occupants in frontal impacts Applies to all seats except: Rearmost Side facing Back-to-back Folding auxiliary jump Temporary,FMVSS 202 Testing,Reduce frequency and severity of neck injury (whiplash) in rear-end collisions Applies to all seats with head restraints Moment applied to seat back to establish displaced torso line Same moment applied to head restraint Ultimate load of 200 lbs. applied,FMVSS 207 Testing,Demonstrates that the seat vehicle attachment assemblies can sustain forward and rearward forces from vehicle impacts Applies to all occupant seats Load applied is 20 times weight of complete seat forward and rearward,FMVSS 210 Testing,Establishes requirements for seat belt anchorages and reduced likelihood of failure in frontal impact Applies to single and multi-occupant seats with seat belts attached Usually combined with FMVSS 207 forward anchorage test,FMVSS 225 Testing,Establishes requirements for child restraint anchorage systems to ensure proper location and strength Applies to all child restraint systems and child restraint anchorage systems LATCH (Lower Anchors and Tethers for Children),Worldwide Regulations,United 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),Homologation vs Self-Certification,Homologation is certification by third party chosen by government that items pass tests before government issues its approval Standard for products used in Europe Requires more extensive preparations Self-certification is certification by manufacturer that items pass tests before government issues its approval Standard in North America,
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