SAE J2732-2008

__________________________________________________________________________________________________________________________________________SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefrom, is the sole responsibility of the user.” SAE reviews each technical report at least every five years at which time it may be reaffirmed, revised, or cancelled. SAE invites your written comments and suggestions. Copyright © 2008 SAE International All rights reserved. No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of SAE. TO PLACE A DOCUMENT ORDER: Tel: 877-606-7323 (inside USA and Canada) Tel: 724-776-4970 (outside USA) Fax: 724-776-0790 Email: [email protected] SAE WEB ADDRESS: http://www.sae.org

J2732 JUN2008 SURFACEVEHICLESTANDARD Issued 2008-06

Motor Vehicle Seat Dimensions

RATIONALE

The Motor Vehicle Dimensions Recommended Practice (SAE J1100) has a limited number of seating measurements related to automotive interior space. This document provides additional and more comprehensive dimensional measurements specifically for the design, evaluation and benchmarking of vehicle seats. Coordinate references are established along the cushion and seat back to better define seat characteristics. These dimensions are based primarily on the use of the SAE J4002 HPM-II that provides divot points, support points, a measure of lumbar support prominence, and many seat measures that can be taken independent of the seating package. Many of the definitions and measurements can be made with the SAE J826 H-point machine (HPM); however, the measured values may not be identical to values taken using HPM-II.

TABLE OF CONTENTS

INTRODUCTION..................................................................................................................................................................... 2

1. SCOPE.......................................................................................................................................................... 2

2. NORMATIVE REFERENCES....................................................................................................................... 32.1 Applicable Publications ................................................................................................................................. 32.1.1 SAE Publications........................................................................................................................................... 3

3. DEFINITIONS ............................................................................................................................................... 4

4. CODE EXPLANATION ................................................................................................................................. 74.1 Prefix Codes.................................................................................................................................................. 74.2 Seat Position Codes ..................................................................................................................................... 84.3 Cross Sectional Code ................................................................................................................................... 8

5. SEAT DIMENSIONS..................................................................................................................................... 9

6. NOTES........................................................................................................................................................ 186.1 Marginal Indicia ........................................................................................................................................... 18

APPENDIX A (INFORMATIVE) RECOMMENDED SEAT CROSS SECTIONS............................................................... 19

BIBLIOGRAPHY ................................................................................................................................................................... 22

SAE J2732 Issued JUN2008 - 2 -

INTRODUCTION

The tools and procedures for determining motor vehicle seat dimensions used in this document are based on the SAE J4002 H-Point Machine (HPM-II). Many of the definitions and measurements can be made with the SAE J826 H-point machine (HPM), however the measured values may not be identical to values taken using HPM-II. Since the SAE J826 HPM does not have support or divot points, dimensions based on these points are difficult to measure in the field, but can readily be measured in CAD if desired. The LSP measure is not available with the SAE J826 HPM. Users shall document and maintain a record noting whenever the SAE J826 HPM is used in making the measurements cited in this document.

H-point devices are used (1) during vehicle design and development to establish interior reference points and dimensions for occupant packaging, (2) to validate (audit) the location of these key reference points and dimensions on physical properties, and (3) to measure competitive vehicles for benchmarking. The procedures employed for each usage vary somewhat.

SAE J4002 describes the use of the HPM-II in auditing vehicle seats and other interior compartment dimensions. SAE J4003 describes the use of the HPM-II in benchmarking. Audits are conducted by regulatory agencies and OEMs to assess how closely the vehicle is manufactured to its design intent. Although serving different purposes, auditing and benchmarking procedures are very similar. The most significant difference between them is that audits use actual design intent values to set up the vehicle and position the seat, whereas benchmarking is used to discover the design intent values for competitor vehicles.

1. SCOPE

This document provides dimension definitions that facilitate geometric quantification and evaluation of seats. Dimensions described in this document have been designed to be measured in a CAD environment; however, many dimensions require the HPM position and attitude. This can be obtained by physically establishing H-point using benchmark or auditing procedures OR by measuring the HPD within a CAD or modelling system. Refer to the appropriate document for these procedures.

These dimensions are package independent in that they do not require use of the HPM-II supplemental thigh/leg/shoe. Three types of seat geometry reference points and measurements have been developed:

• Simple reference points and measurements not related to H-point.

• H-point dependent reference points and measurements that utilize the seat characterization capabilities of the HPM to quantify seat measurements.

• Cross sectional seat trim outlines.

For convenience and simplicity, many terms associated with H-point devices use human body parts in their name. However, they should not be construed as measures that indicate interaction with any or all occupants concerning accommodation, human capabilities, or comfort.

H-point devices do not represent the size or posture of any category of occupant.


2. NORMATIVE REFERENCES

2.1 Applicable Publications

This document contains provisions which reference the following documents. The latest edition of the reference applies.

2.1.1 SAE Publications

Available from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org.

SAE J182 Motor Vehicle Fiducial Marks and Three-dimensional Reference System

SAE J826 Devices for Use in Defining and Measuring Vehicle Seating Accommodation

SAE J1100 Motor Vehicle Dimensions

SAE J4002 H-Point Machine (HPM-II) Specifications and Procedure for H-Point Determination—Auditing Vehicle Seats

SAE J4003 H-Point Machine (HPM-II)—Procedure for H-Point Determination—Benchmarking Vehicle Seats


3. DEFINITIONS

For the purposes of this document, the following definitions apply.

TABLE 1 - SEAT DEFINITIONS

Term Definition Figure A-Surface Surface of a seat, or any of its components, that is closest to the

occupant. For example, the A-surface of the foam pad is the surface the occupant sits on.

3

B-Surface Surface of a seat, or any of its components, that is furthest from the occupant (opposite the A-surface). For example, the B-surface of the foam pad is the surface in contact with the frame.

3

Bench Seat Seat structure designed to hold multiple occupants. N/A Biteline (seat bight) Area close to and including the intersection of the surface of the

vehicle seat cushion and seat back. 2

Bolster Raised contour at lateral edges of the seat cushion and seat back. 2 Bucket Seat Seat structure designed to hold a single occupant usually contoured to

hold the occupant. N/A

Centerline of Occupant (C/LO) Lateral (Y) centerline of an occupant in a given designated seating position. See SAE J1100. C/LO is repeated in this section for convenience. In the case of a CL trench or decorative raised regions, a lateral offset can be used to approximate the centerline.

2

Cross Car Lateral direction across vehicle (+Y, -Y). 1 Deflection (HPM) Distance between the free unloaded seat trim contour prior to HPM

installation and the HPM surface, when loaded in the seat.4

Head Restraint Protective device that limits the rearward displacement of a seated occupant’s head relative to the occupant’s torso.

2

Insert Primary seating region between the bolsters on the seat cushion and seat back, usually defined with a seam or line in the trim A-Surface.

2

Lumbar Region Area of the seat back that provides support for an occupant’s lower back – can be adjustable or static.

N/A

Protruded (Extended) Refers to an adjustable mechanism when it is in its maximal or projected state.

N/A

Retracted Refers to an adjustable mechanism when it is in its minimal or withdrawn state.

N/A

Seat Adjuster Refers to mechanisms used to alter position, shape, or support characteristics of the seat.

N/A

Seat Back Part of the seat that supports the occupant’s back. 2 Seat Cushion Part of the seat that supports the occupant’s buttocks and thighs. 2 Split Bench Seat Seat structure designed to hold multiple occupants that may be split

for independent adjustment of two or more occupant positions. N/A

Tie-down Depression or line in the A-surface of the trim cover created by the attachment of trim to seat components.

N/A

Trench Recess in the foam pad used to accommodate or attach seams in the trim cover.

2

Trim Cover Material or attachment used to cover a seat. N/A Trim Prominence Most prominent point on the undeflected profile of the seat trim

defined by the tangent point of a line parallel to a reference line such as the Cushion or Torso (Back) Line.

3


FIGURE 1 - THREE DIMENSIONAL REFERENCE SYSTEM, SEE SAE J1100

FIGURE 2 - GENERAL SEAT DEFINITIONS


FIGURE 3 - GENERAL SEAT DEFINITIONS (CROSS SECTION)

TABLE 2 - HPM SPECIFIC DEFINITIONS

Term Definition Figure Cushion Line Line from the H-point through the C1 divot point. See SAE J4002. 4 D-point Located on the bottom of the cushion pan, at the lateral centerline, 25.5 mm

(15 degrees) rearward of the H-point (when cushion angle equals 0). This point is identified by a divot point on the surface of the cushion pan. See SAE J1100.

4

Divot Points Fourteen divot points are provided on the HPM. See SAE J4002. N/A Exit Point Point where the undeflected trim separates from the manikin’s surface. Exit

Points are determined using CAD. Lateral Exit Points are referenced to the HPM centerline. The measurement process assumes that HPM centerline is at the centerline of occupant (C/LO).

4

H-point Point at the pivot center of the back pan and cushion pan assemblies, located on the lateral centerline of the H-point device (HPM or HPD). See SAE J4002. NOTE 1: When an H-point device is properly positioned within a vehicle – either in CAD or in an actual physical property – the location of the H-point relative to the vehicle is used as a vehicle reference point. If the seat is moved, the location of the H-point within the vehicle is changed. Therefore, adjustable seats will have more than one H-point location, while fixed seats will have only one H-point location.NOTE 2: H-points are often referred to as hip points or hip pivot points. However, they do not accurately represent the location of the human hip joint.

4

Support Points There are nine support points: 5 located on the outer surface of the cushion pan and 4 on the back pan assembly. See SAE J4002.

N/A

Torso (Back) Line Line from the H-point through the sliding thoracic pivot (B1 divot point). See SAE J4002.

4


FIGURE 4 - HPM SPECIFIC DEFINITIONS

4. CODE EXPLANATION

Each dimension is assigned a code, which consists of an alpha prefix and a number. The letters denote the direction or type of measurement (e.g. W - Width, A - Angle). See Table 3. Numeric codes relate to the type of vehicle dimension. Seat specific dimensions range between 1000–1999 (e.g. W1020). See Table 4.

Users shall record pertinent design, setup, and measurement information, including settings for user adjustable features (e.g. lumbar support or thigh extender), CAD vs. field measurement, and the HPM (SAE J4002 / SAE J826) used to set the reference position and attitude.

4.1 Prefix Codes

TABLE 3 - PREFIXES

Letter Meaning W Widths associated with seats (cross car distance). L Lengths associated with seats. H Heights associated with seats. A Angles associated with seats. R Radii associated with seats.

TABLE 4 - NUMERIC SCHEME

Number Range Type of Dimension 1–99 Interior (General Seat Dimensions).

1000–1199 Seat Cushion Lateral Dimensions. 1200–1399 Seat Cushion Centerline Dimensions. 1400–1599 Seat Back Lateral Dimensions. 1600–1799 Seat Back Centerline Dimensions. 1800–1999 Seat Head Restraint Dimensions.


4.2 Seat Position Codes

These dimensions can be applied to several designated seating positions. In order to indicate a specific seat position, the basic alphanumeric code remains the same, but an additional alphanumeric code is added (e.g., H30-1-L, H30- 2-R, H30-3-C). The number indicates the designated seating row. See Table 5. The letter indicates the seating position in that particular row. See Table 6 (e.g. W1015-1-L).

TABLE 5 - SEATING ROW

Row Number Designated Seating Row -1 Front Row Measurement. -2 Second Row Measurement. -3 Third Row Measurement. -4 Fourth Row Measurement. -5 Fifth Row Measurement.

TABLE 6 - SEATING POSITION (SUFFIX)

Letter Designated Seating Position -L Measurement taken for the left, outboard designated seating position. (-Y in vehicle

coordinates)-R Measurement taken for the right, outboard designated seating position. (+Y in

vehicle coordinates) -C Measurement taken for the center designated seating position. -B Measurement taken for an entire bench seat (such as overall width).

4.3 Cross Sectional Code

Selected dimensions are measured at a given distance from H-point along or normal to a given reference line and are denoted with _X (where X equals the distance in mm from H-point) following the alphanumeric prefix (e.g. W1020_100). See Figure 5 and Appendix A.

FIGURE 5 - CROSS SECTIONS AND CENTERLINE SECTIONS


5. SEAT DIMENSIONS

The dimension definitions that follow are shown with no suffix codes to indicate seat row or position. In practice the proper suffix codes should be added to identify seat aspects. Note also that certain seat and package dimensions are repeated in this Section for convenience.

TABLE 7 - GENERAL SEAT DIMENSIONS

Code Dimension Definition Figure A27 Cushion Angle Angle of the Cushion Line from the horizontal with the

HPM loaded in the seat with the seat at design attitude. See SAE J4002.

6

A42 Hip Angle Included angle between the Cushion Line and Torso (Back) Line with the seat at design attitude. See SAE J1100.

6

A40 Torso Angle Angle measured between a vertical line through the H-point and the Torso (Back) Line. See SAE J1100.

6

L81 Lumbar Support Prominence

LSP is a measure of the attitude (posture) of the H-point device. It is defined as 57 mm minus the distance from the lumbar-pelvic pivot point to the Torso (Back) line, measured normal to the Torso (Back) line. When LSP = 0, the posture is referred to as neutral. The suffix following L81 identifies the designated seating position. See SAE J1100.

6

FIGURE 6 - BASIC HPM DIMENSIONS


TABLE 8 - SEAT CUSHION LATERAL CROSS SECTION DIMENSIONS

Code Dimension Definition Figure W1000_X Seat Cushion Width Width across the seat cushion soft trim surface within a

cross sectional plane normal (90 deg) to the Cushion Line.

7a

W1020_X Seat Cushion Bolster Width

Width between the highest points on the bolsters within a cross sectional plane normal (90 deg) to the Cushion Line.

7a

W1040_X Seat Cushion Insert Width

Width of the insert between the bolsters within a cross sectional plane normal (90 deg) to the Cushion Line. In certain cases this measure is not definable.

7a

H1060_X Seat Cushion Bolster Height

Height of the bolsters above the centerline (C/L) insert within a cross sectional plane normal (90 deg) to the Cushion Line. In certain cases this measure is not definable.

7a

R1080_X Seat Cushion Bolster Radius

Radius defined by the arc of the highest point of the outboard bolster, the highest point of the inboard bolster, and the surface of the centerline (C/L) insert within a cross sectional plane normal (90 deg) to the Cushion Line. In certain cases this measure is not definable.

7c

W1100_X Seat Cushion Lateral Exit Point

Distance from the seat centerline to the lateral exit points within a cross sectional plane normal (90deg) to the Cushion Line. If the seat is not symmetrical use only the outboard side.In the case of a trench use furthest lateral exit pt.

7b

H1120_X Seat Cushion Trim Deflection

Distance from the manikin surface to the undeflected seat cushion surface measured within a cross sectional plane normal (90 deg) to the Cushion Line.

7b

H1140_X Seat Cushion Bolster Asymmetry

Difference in outboard bolster height and inboard bolster height within a cross sectional plane normal (90deg) to the Cushion Line. Center seats should use the same convention as the left outboard seat position. Value will be negative if inboard bolster is higher than outboard bolster.

7c

FIGURE 7A - SEAT CUSHION LATERAL CROSS SECTION DIMENSIONS


FIGURE 7B - HPM SPECIFIC SEAT CUSHION LATERAL CROSS SECTION DIMENSIONS

FIGURE 7C - SEAT CUSHION LATERAL CROSS SECTION -BOLSTER ASYMMETRY AND RADIAL DIMENSIONS


TABLE 9 - SEAT CUSHION CENTERLINE SECTION DIMENSIONS

Code Dimension Definition Figure H1200_X Seat Cushion Trim

Prominence to Cushion Line

Distance measured normal (90 deg) to the Cushion Line from the Seat Cushion Trim Prominence to the Cushion Line.

8a

L1220_X Seat Cushion Trim Prominence to H-point

Distance measured parallel to the Cushion Line from H-point to the Seat Cushion Trim Prominence.

8a

L1240_X Cushion Biteline Exit Point

Distance measured parallel to the Cushion Line from H-point rearward to a line normal to the Cushion Line at the exit point.

8b

L1260_X Cushion Thigh Exit Point Distance measured parallel to the Cushion Line from H-point forward to a line normal to the Cushion line at the exit point. Usually offset from centerline of occupant (C/LO) by 100mm.

8b

L1280_X Seat Cushion Length to H-point

Distance measured parallel to the Cushion Line from H-point to a line normal (90 deg) to the Cushion Line tangent to the front of the cushion at centerline of occupant (C/LO).

8a

L1300_X Seat Cushion Tie-down Location

Distance measured parallel to the Cushion Line from H-point to a line normal to the Cushion Line at the closest cross car tie down on the A-Surface of the seat. This measurement is positive (forward of H-point) or negative (rearward of H-point).

8a

FIGURE 8A - SEAT CUSHION CENTERLINE SECTION


FIGURE 8B - HPM SPECIFIC SEAT CUSHION CENTERLINE SECTION


TABLE 10 - SEAT BACK LATERAL CROSS SECTION DIMENSIONS

Code Dimension Definition Figure W1400_X Seat Back Width Width across the soft trim surface within a cross

sectional plane normal (90 deg) to the Torso (Back) Line.

9a

W1420_X Seat Back Bolster Width Width between the most forward points of the bolsters within a cross sectional plane normal (90 deg) to the to the Torso (Back) Line.

9a

W1440_X Seat Back Insert Width Width of the insert between the bolsters within a cross sectional plane normal (90 deg) to the to the Torso (Back) Line. In certain cases this measure is not definable.

9a

H1460_X Seat Back Bolster Height Distance of the bolsters forward of the insert at the centerline (C/L) within a cross sectional plane normal (90 deg) to the Torso (Back) Line. In certain cases this measure is not definable.

9a

R1480_X Seat Back Bolster Radius Radius defined by the arc of the highest point of the outboard bolster, the highest point of the inboard bolster, and the surface of the centerline (C/L) insert within a cross sectional plane normal (90deg) to the Torso (Back) Line. In certain cases this measure is not definable.

9c

W1500_X Seat Back Lateral Exit Points Distance from the seat centerline to the lateral exit points within a cross sectional plane normal (90 deg) to the Torso (Back) Line. If the seat is not symmetrical, use only the outboard side. In the case of a trench use furthest lateral exit pt.

9b

H1520_X Seat Back Trim Deflection Distance from the manikin surface to the undeflected trim, measured within a cross sectional plane normal (90 deg) to the Torso (Back) Line.

9b

H1540_X Seat Back Bolster Asymmetry

Difference in bolster depth on outboard side to inboard within a cross sectional plane normal (90 deg) to the Torso (back)line. Center seats should use the same convention as the left outboard seat position.Value will be negative if inboard bolster is bigger than outboard bolster

9c

FIGURE 9A - SEAT BACK LATERAL CROSS SECTION DIMENSIONS


FIGURE 9B - HPM SPECIFIC SEAT BACK LATERAL CROSS SECTION DIMENSIONS

FIGURE 9C - SEAT BACK LATERAL CROSS SECTION -BOLSTER ASYMMETRY AND RADIAL DIMENSIONS


TABLE 11 - SEAT BACK CENTERLINE SECTION DIMENSIONS

Code Dimension Definition Figure L1600_X Seat Back Trim

Prominence to Torso (Back) Line

Distance from the seat Back Trim Prominence to the Torso (Back) Line measured normal (90 deg) to the Torso (Back) Line along centerline of occupant C/LO.

10a

H1620_X Seat Back Trim Prominence to H-point

Distance from the Seat Back Trim Prominence to the H-point measured parallel to the Torso (Back) Line along centerline of occupant (C/LO).

10a

H1640_X Back Biteline Exit Point Distance from the H-point parallel to the Torso (Back) Line to a line normal to the Torso (Back) Line at the exit point. This measure can be either positive (above H-point) or negative (below H-point).

10b

H1660_X Upper Back Exit Point Distance from the H-point parallel to the Torso (Back) Line to a line normal to the Torso (Back) Line at the exit point.

10b

H1680_X Seat Back Height from H-point without Head Restraint

Distance from the H-point along the Torso (Back) Line to the intersection at a line normal (90 deg) to the Torso (Back) Line, tangent to the top of the seat back at centerline of occupant (C/LO). Head restraint is excluded. This measurement does not apply for integrated head restraints.

10a

H1700_X Seat Back Tie-Down Location

Distance from H-point parallel to the Torso (Back) Line to a line normal to the Torso (Back) Line at the closest cross car trench in the seat back. This measurement can be positive (above H-point) or negative (below H-point).

10a

FIGURE 10A - SEAT BACK CENTERLINE SECTION DIMENSIONS


FIGURE 10B - HPM SPECIFIC SEAT BACK CENTERLINE SECTION DIMENSIONS

TABLE 12 - HEAD RESTRAINT DIMENSIONS

Code Dimension Definition Figure H1800_X Seat Back Height from

H-point with Head Restraint

Distance measured parallel to the Torso (Back) Line from the H-point to the intersection of a line normal (90 deg) to the Torso (Back) Line and tangent to the top of the headrest.If the head restraint is adjustable it is placed in the full down position. This dimension is similar to ECE Head Restraint Height

11

W1820 Head Restraint Width Width across trimmed surfaces of the head restraint at widest points.

11

H1840_X Head Restraint Height Distance measured parallel to the Torso (Back) Line from a line normal (90 deg) to the Torso (Back) Line tangent to the bottom of the head restraint to a line normal to the Torso (Back) Line tangent to the top of the head restraint.

11


FIGURE 11 - HEAD RESTRAINT DIMENSIONS

6. NOTES

6.1 Marginal Indicia

A change bar (I) located in the left margin is for the convenience of the user in locating areas where technical revisions, not editorial changes, have been made to the previous issue of this document. An (R) symbol to the left of the document title indicates a complete revision of the document, including technical revisions. Change bars and (R) are not used in original publications, nor in documents that contain editorial changes only.

PREPARED BY THE SAE HUMAN ACCOMMODATION AND DESIGN DEVICES COMMITTEE


APPENDIX A - (INFORMATIVE) RECOMMENDED SEAT CROSS SECTIONS

Dimensions described in this document can be measured at distances from H-point along a given reference line. This distance is denoted by _X where X is the offset from H-point (see Figures below). This section describes a minimum set of recommended cross sections intended for seat comparisons and evaluations.

Although used for reference these HPM sections and locations do not represent the size or posture of any category of occupant. Additionally, the H-point does not represent the location of the human hip joint.

TABLE A1 - SEAT CUSHION DIMENSIONS

Code Section Definition Figure _0 Lateral Cross

Section0 mm forward of H-point (plane normal to cushion line through CP1).

A1

_125 Lateral Cross Section

125 mm forward of H-point (plane normal to cushion line through CP2).

A1


250 mm forward of H-point (plane normal to cushion line through CP3).

A1, A3

_0 Centerline Cross Section

0 mm lateral of H-point (plane parallel to the cushion and torso (back) line through H-point).

A2


±110 mm on either side of H-point (dependent on outboard or inboard requirement).

A2

TABLE A2 - SEAT BACK DIMENSIONS


35 mm above the H-point (plane normal to torso (back) line through BP1).

A1



A1



A1, A4


0 mm lateral of H-point (plane parallel to the cushion and torso (back) line through H-point).

A2


±110 mm on either side of H-point (dependent on outboard or inboard requirement).

A2


FIGURE A1 - RECOMMENDED LATERAL CROSS SECTIONS REFERENCED FROM H-POINT

FIGURE A2 - RECOMMENDED CENTERLINE SECTIONS REFERENCED FROM H-POINT(SHOWS POSITIVE AND NEGATIVE OFFSET)


FIGURE A3 - EXAMPLE HPM SEAT CUSHION CROSS SECTION THROUGH THIGH (250 mm FORWARD OF H-POINT)

FIGURE A4 - EXAMPLE HPM SEAT BACK CROSS SECTION THROUGH SHOULDERS (350 mm ABOVE H-POINT)


BIBLIOGRAPHY

ASPECT/SAE Seat Dimensions Task Group, “Proposed Seat Dimension Definitions for SAE J1100 Derived from Aspect (HPMII),” Final Report, November 30, 1999

Documents

SAE J2732-2008