Automotive Seat Research Articles

승객의 안락감에 미치는 럼버 서포트의 변형에 관한 연구

럼버 서포트는 허리에 가해지는 압력을 지지하여 장시간 운전시 피로감을 해소하는 자동차 시트의 부품이다. 본 연구에서는 자동차 시트의 럼버 서포트를 모델링 하였으며, 해석은 럼버 서포트의 베드부분에 여러 가지의 비드를 보강하여 사람이 자동차 시트에 앉아 있을 때 작용하는 하중에 따른 변형에 대해 구조해석을 하여 안락성면에서 적합한 모델을 찾는 것이 주된 목적이다. 5줄 보강타입과 풀타입이 5mm안쪽의 변형과 500 N의 접촉력이 나타나 승객의 안락감에 있어 가장 적합하고 내구성도 양호한 것으로 사료된다. Lumber support as the part of automotive seat supports the pressure applied on waist by clearing the tiredness of passenger at long driving. In this study, lumbar support of automotive seat is modelled. Various bids are built up at its bed. The main purpose is to look for adequate model on comfortableness by calculating displacement according to applied force when some passenger sit at automotive seat. Full build -up type of 5 rows can be seen most suitable for passenger's comfortableness and its durability as the inner displacement of 5mm and contact force of 500 N.

자동차 시트 틸팅 각도에 따른 기어박스 마찰소음 영향도

The squeak propensity in the gear box of an automotive seat system is investigated analytically. The mating parts in the gear box are the lead screw and the nut, where the friction stresses are exerted on the thread of the screw. The lead screw is modeled as a circular beam allowing the bending and torsional vibrations. In the system, the lead screw converts rotating to translating motion so that it moves the automotive seat slightly tilted on the floor. The tilting angle is considered one major parameter in this study. Therefore, the equations of motion associated with the non-conservative friction force are derived with the inclusion of the tilting angle. It is found that the squeak noise corresponds to the several bending modes of the lead screw and its propensity is increased by the tilting angle of the seat.

Thermal Comfort Modeling of Cooled Automotive Seats

Thermal Comfort Modeling of Cooled Automotive Seats

Influence of Hardness of Seat Pad on Sitting Comfort of Automotive Seat

In this study, a sitting comfort of five automotive seats, whose hardness of these cushion pads was changed, and shape and structure of seats were the same, was evaluated by only tactile sensation while sitting on these seats. The adjectives used for the sensory evaluation of seat comfort by the human tactile sensation were examined by the factor analysis. As the analysis result, the sitting comfort of driver's seats was evaluated by two adjectives sporty-high-class and voluminous-casual. From the correlations between physical properties of cushion pad and sensory evaluations for seats, it is found that the image adjectives have correlations with the cushion properties of pad.

Biomechanical shoulder loads and postures in light automotive assembly workers: Comparison between shoulder pain/no pain groups

The number of workplace shoulder compensation claims resulting from musculoskeletal disorders (MSDs) has decreased slightly in recent years, however the median number of days off work remains unchanged, which suggests an increase in injury severity. Little information is available regarding cumulative shoulder exposures, and there is no information on their impact on shoulder pain. Seventy-nine automotive seat frame assembly workers completed a questionnaire about the prevalence and severity of shoulder pain and were videotaped performing assembly tasks. 3DMatch, a posture-matching software program, was used to calculate the peak and cumulative shoulder moments and forces by matching postures seen in the video with predetermined ranges of posture to be used in the biomechanical model. Of the 45.6% who reported shoulder pain, there was a mild correlation of pain severity with posterior shear of the shoulder. There were no significant differences in peak loads between Pain and No Pain groups; however, the No Pain group experienced significantly more cumulative caudal shear. Although there was no difference in percent time spent in different flexed postures between pain groups, those working some jobs may be at an increased risk of developing MSDs based on the amount of time spent in flexed postures, as well as the peak flexion moment acting on the shoulder.

Coating of Al mould surfaces with polytetrafluoroethylene (PTFE), fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA) and ethylene-tetrafluoroethylene (ETFE)

AbstractBecause of low cost, easily productivity and high thermal conductivity, aluminum (Al) moulds are preferred in the production of the polyurethane (PUR) parts. In this study, adhesion behavior and surface properties of coated materials between mould used in the production of automotive seat and PUR materials were investigated. Four different polymer types were coated on Al mould and they were characterized using contact angle, surface roughness, coating thickness, adhesion, cross-cut and SEM test methods. It was found that, PFA has the least value of surface roughness and ETFE has the highest one in the four different coatings produced. After holding period in isocyanate, decrease were measured on the angle values of all coatings. In the contact angle measurements before and after isocyanate tests, PFA exhibited the highest contact angle value.

Development and performance analysis of an automotive power seat for disabled persons

As the number of disabled people grows, independence and mobility become a priority for those individuals. To achieve this goal, a ‘Turny-type power seat’ was developed in this study to assist a disabled person rise from a vehicle without trouble. The design and modeling of the power seat were performed using AutoCAD and CATIA software. The major motions of the power seat system are swiveling, sliding, and extending, which are accomplished primarily by DC motors, chains, and gears. Most of the power seat parts were made from mild steel. Welding technology was used throughout the frame fabrication. To ensure the safety and stability of the power seat, various tests were performed, and the results analyzed. The static analysis of the power seat was carried out by ANSYS 11.0. The results showed that the power seat conformed to the Americans with Disabilities Act (ADA) standards. The durability test was performed by repeatedly rotating and sliding the power seat under loading conditions. Dynamic crash simulation was carried out using the LS-DYNA software. The durability test ensured a longer life of the power seat, while the crash analysis showed a small rotational distortion that was not harmful to passengers. However, the front seat had a slightly larger forward displacement, which was not comfortable for passengers. Therefore, further modifications of the power seat should be done to improve the performance, with attention given to the reduction of the forward displacement in the event of a crash.

Repeatability, Reproducibility, and Validity of a New Method for Characterizing Lumbar Support in Automotive Seating

This article describes a new and more repeatable, reproducible, and valid test method for characterizing lumbar support in automotive seating. Lumbar support is important because it affects occupant accommodation and perceptions of seat comfort. Assessing only the lumbar mechanism--particularly in terms of travel--is inadequate because it does not consider the effects of trim and foam. The Society of Automotive Engineers' next-generation H-Point machine and associated loading protocol were used as the basis for the new test. The method was found to satisfy minimum gage repeatability and reproducibility requirements. Validity was demonstrated through a regression model that revealed 93.9% of the variance in subjective ratings of poor uncomfortable lumbar support can be explained by two objective indicators: (1) lumbar support prominence in the full-off position and (2) effective travel. The method can be used to differentiate between seats offering two-way adjustable lumbar support. The best two-way adjustable lumbar seat systems are those that couple little to no lumbar support in the starting or off position (i.e., they are nonintrusive) with a considerable amount of effective or perceptible travel. The automotive industry has long needed a way to address the fact that consumers want more lumbar support than their seats currently supply. This contribution offers a method to objectify an important aspect of automotive seating comfort-namely, lumbar support. This should help human factors professionals produce, but not necessarily guarantee, better consumer ratings.

A study on the influence of the seat and head restraint foam stiffnesses on neck injury in low speed offset rear impacts

Soft tissue neck injury (STNI) is thought to be related to automotive seat characteristics, and it is important to know how the stiffness of the seatback and head restraint foam affect the occupant’s motions in low speed rear impacts. The combined MADYMO(MAthematical DYnamic MOdel, TNO) 50th percentile facet male human body model with a detailed neck model was selected for this analysis. In order to determine the relationship between the occupant’s motions and seatback and head restraint foam stiffnesses, 40% offset rear impact simulations were performed by changing the stiffness of seatback and head restraint. Simulated results show that the maximum acceleration of head and trunk would tend to increase with those stiffnesses. Increased stiffness of the seatback and head restraint resulted in increased ligament and disc forces. On the other hand a proper combination of seatback and head restraint stiffness can reduce a possible neck injury. It is clear that an appropriate combination of stiffnesses between seatback and head restraint allows to minimize a neck injury.

Friction-Induced Vibration in Lead Screw Systems: Mathematical Modeling and Experimental Studies

Lead screw mechanisms are used to convert rotary to linear motion. The velocity-dependent coefficient of friction at the contact between lead screw and nut threads can lead to self-excited vibrations, which may result in excessive noise generated by the system. In this paper, based on a practical example of a powered automotive seat adjuster, the nonlinear dynamics of lead screw systems is studied. A test setup is developed to perform experiments on the horizontal motion drive. The experimental results are used in a novel two-step identification approach to estimate friction, damping, and stiffness parameters of the system. The identified parameters together with other known system parameters are used in the numerical simulations. The accuracy of the mathematical model is validated by comparing numerical simulation results with actual measurements in cases where limit cycles are developed. Using simulation results for a range of lead screw angular velocities and axial forces, regions of stability were found. Also, the effects of damping and stiffness parameters on the steady-state amplitude of vibration were investigated.

Parametric modelling approach for development of an automotive bucket seat frame

This paper presents a design process of an automotive bucket seat frame using a parametric modelling approach. The design process involves, first, optimising a generic seat frame using OptiStruct optimisation software. Then, a parametric model of the seat frame was developed based on the optimisation analysis results using CATIA V5. The design parameters were changed in the parametric model and numerous static tests were also performed using CATIA V5. Design of Experiment (DOE) study was then conducted using MINITAB to optimise the design parameters. Finally, the optimised seat frame was evaluated based on the requirements of the Federal Motor Vehicle Safety Standards (FMVSS) using in LS-DYNA.

Leggett & Platt, Inc.

AbstractFurniture and Fixtures (MIC: SIC: 2519 NAIC: 337121)Leggett & Platt is engaged in designing and producing a range of components and products that are used in homes, offices, retail stores and automobiles. Co.'s products include manufactured components for residential furniture and bedding, adjustable beds, carpet underlay, retail store fixtures and point‐of‐purchase displays, office furniture, drawn steel wire, automotive seat support and lumbar systems, and machinery for wire forming, sewing, and quilting. As of Dec 31 2007, Co.'s operations were organized into 22 business units, which are divided into 10 groups under four segments: Residential Furnishings; Commercial Fixturing & Components; Industrial Materials; and Specialized Product.

Automotive Seating Foams with Excellent Riding Comfort Prepared by a Novel Polypropylene Glycol

Automotive Seating Foams with Excellent Riding Comfort Prepared by a Novel Polypropylene Glycol

Leggett & Platt, Inc.

AbstractFurniture and Fixtures (MIC: SIC: 2519 NAIC: 337121)Leggett & Platt is engaged in designing and producing a range of components and products that are used in homes, offices, retail stores and automobiles. Co.'s products include manufactured components for residential furniture and bedding, adjustable beds, carpet underlay, retail store fixtures and point‐of‐purchase displays, office furniture, drawn steel wire, automotive seat support and lumbar systems, and machinery for wire forming, sewing, and quilting. As of Dec 31 2007, Co.'s operations were organized into 22 business units, which are divided into 10 groups under four segments: Residential Furnishings; Commercial Fixturing & Components; Industrial Materials; and Specialized Product.

An Equivalent-Acoustic Finite Element Method for Modeling Sound Absorbing Materials

An equivalent-acoustic finite element method is developed for modeling sound absorbing materials, such as seats and interior trim in the automobile passenger compartment. The equivalent-acoustic method represents the sound absorbing material using acoustic finite elements with frequency-dependent material properties determined from the measured acoustic impedance of sound absorbing material samples. Solution of the equivalent-acoustic model within the Nastran computer capability and coupling of the model with an acoustic finite element model of a surrounding enclosure, such as the passenger compartment, are developed. The accuracy of the equivalent-acoustic method is assessed for modeling a sound absorbing material in a one-dimensional impedance tube, a foam layer in a rectangular box enclosure, and an automotive seat in a semi-reverberant enclosure.

Leggett & Platt, Inc.

AbstractFurniture and Fixtures (MIC: 11.10 SIC: 2519 NAIC: 337121)Leggett & Platt is engaged in designing and producing a range of components and products that are used in homes, offices, retail stores and automobiles. Co.'s products include manufactured components for residential furniture and bedding, adjustable beds, carpet underlay, retail store fixtures and point‐of‐purchase displays, office furniture, drawn steel wire, automotive seat support and lumbar systems, and machinery for wire forming, sewing, and quilting. As of Dec 31 2007, Co.'s operations were organized into 22 business units, which are divided into 10 groups under four segments: Residential Furnishings; Commercial Fixturing & Components; Industrial Materials; and Specialized Product.

Leggett & Platt, Inc.

AbstractFurniture and Fixtures (MIC: 11.10 SIC: 2519 NAIC: 337121)Leggett & Platt is engaged in designing and producing a range of components and products that are used in homes, offices, retail stores and automobiles. Products include manufactured components for residential furniture and bedding, components for office furniture, drawn steel wire, automotive seat support and lumbar systems, adjustable beds, and bedding industry machinery for wire forming, sewing and quilting. As of Dec 31 2006, Co.'s operations were organized into 29 business units, which are divided into 11 groups under five segments: Residential Furnishings; Commercial Fixturing & Components; Aluminum Products; Industrial Materials; and Specialized Products.

A ramp—heated plate method for measuring heat and water vapour transport in seats

In this paper, an experimental ramp method is presented which was used to quantify the capability of an automotive seat to move heat and moisture away from its surface. The method involved placing an indenter on a seat cushion for a fixed time period. Average heat and mass transfer rates were measured to compare seats. In addition, an effective effusivity was defined and measured to quantify the seat's thermal property. The ramp method was used to compare the difference in dry ventilated and dry non—ventilated seats. An increase of 82 per cent in heat transfer was observed. The ventilated and non—ventilated seat effusivities were 440 W s1/2/m2 K and 292 W s1/2/m2 K respectively. In comparing wet ventilated with wet non—ventilated seats, an increase of 60–94 per cent in mass transfer was observed. Also, the method was used to compare the difference in positive—pressure and negative—pressure ventilation systems. The positive—pressure system demonstrated an increase over the negative—pressure system in dry heat transfer rate of 32 per cent. Both were comparable in terms of mass transfer capability.

居眠り運転防止シート(自動車,<メカライフ特集>のりもの-人と乗物のいい関係-)

居眠り運転防止シート(自動車,<メカライフ特集>のりもの-人と乗物のいい関係-)

HIGHLY RELIABLE CAE MODEL, THE KEY TO STRATEGIC DEVELOPMENT OF ADVANCED TDS

In recent years, the advanced manufacturing industry is engaging in a "global production strategy — for simultaneous achievement of QCD". A close look at the development designing and production process stage reveals an excessive repetition of "experiment, prototyping, and evaluation" that prevents the "scale-up effect" generated in the bridging stage between prototyping, experiment, evaluation, and mass production. Consequently, what is urgently needed, is innovation to promote the advance from the conventional evaluation-based development, that uses the prototyping and experiment process which had long supported highly reliable designing, to a CAE prediction-based designing process. To accomplish this, a new development designing technique was established, the "Highly Reliable CAE Model. This is the key to strategic promotion of the "Total Integrated Development Design model — Advanced TDS" which utilizes the core element of the "Total Development System, TDS" of "New JIT". In an effort to realize this, the author has proposed the "high quality assurance model for super short period development designing, a "Highly Reliable CAE Numerical Simulation" and demonstrated its effectiveness. As an application example, a simulation technology was developed for molding urethane foam and it was implemented as the "Production of CAE Software for Molding Automotive Seat Pads — Urethane Foam Molding Simulator".