1、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 entirelyvoluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefro
2、m, 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 2002 Society of Automotive Engineers, Inc.All rights reserved. No part of this
3、 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 (o
4、utside USA)Fax: 724-776-0790Email: custsvcsae.orgSAE WEB ADDRESS: http:/www.sae.orgSURFACEVEHICLERECOMMENDEDPRACTICEJ332REV.NOV2002Issued 1969-01Revised 2002-11Superseding J332 AUG1981Testing Machines for Measuring the Uniformity ofPassenger Car and Light Truck TiresForewordThis Document has also ch
5、anged to comply with the new SAE Technical Standards Board Format.References were added as Section 2. All other section numbers have changed accordingly. Also metric is nowthe primary unit of measure followed by english in parentheses.1. ScopeThe comfort and fatigue of vehicle passengers is a major
6、engineering consideration. Among themany factors involved are vibratory and auditory disturbances. Tires participate, among other elements of thevehicle, in exciting vibrations and noises. Furthermore, tires also may generate forces leading to lateral drift ofthe vehicle.This SAE Recommended Practic
7、e describes the design requirements for equipment to evaluate some of thecharacteristic excitations of passenger car and light truck tires which may cause disturbance in vehicles. Thekinds of excitations treated result from nonuniformities in the structure of the tire and have their effect when aveh
8、icle bearing the tire travels on a smooth road.This document also describes some broad aspects of the use of the equipment and lists precautionarymeasures that have arisen out of current experience.The intention underlying these recommendations is to establish a standardized measurement for use by t
9、heengineering community.The evidence from years of experience supports the statistical relevance of data obtained using the type ofequipment and procedures described. However, mechanical instability of materials in response totemperature, storage conditions, and surface contamination, as well as the
10、 previous history of usage, etc.,produces variation in vibratory excitations. Thus, the measurements of individual tires are always to a degreeof uncertain. Nevertheless, larger values of vibratory excitations are usually well identified, and statisticalevaluations of the data usually serve to indic
11、ate properly the vibration excitation quality of production lots oftires for those items considered in this document.Criteria of quality which might be based on measurements made under this document follow from the needs ofindividual engineering applications and are consequently not sufficiently gen
12、eral to be specified here.SAE J332 Revised NOV2002-2-2. Reference2.1 Applicable PublicationThe following publication forms a part of this specification to the extent specifiedherein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE PUBLICATIONAvailable from SAE
13、, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J2047Tire Performance Technology3. Basic Form of MeasurementThe measurement detects the variations in force components produced by amounted and inflated tire while the tire runs unsteered against a smooth road drum at constant axle height overt
14、hat drum and at a constant speed. The varying and constant force components of the tire requiring evaluationare generally four in number. These components of force (see SAE J2047 for axis system) are termed asfollows:a. The variation in radial force.b. The variation in lateral force.c. The variation
15、 in fore-aft force.d. The constant component of the lateral force.4. Apparatus4.1 General The equipment is essentially an axle or spindle supporting a rim on which tires may be readilymounted, a means for loading the tire against a drum at a specified load and for holding a fixed tire-to-drumcenter
16、distance during measurements, and a system for measuring the excitation forces equivalent to those atthe tires spindle as the tire and drum are rotated at prescribed speeds. Rotation can be accomplished bydriving either the tire or the drum. There should be provisions for both clockwise and counterc
17、lockwisedirections of rotation to account for use of tires on left or right sides of the vehicle. The equipment also requiresa means for rapid inflation and deflation of the tire, and for control of inflation pressure during rotation.4.2 StructureThe supporting structure and components of the machin
18、e must be sufficiently rigid to insure thatnatural frequencies of the machine assemblies (which may be ultimately detected in the measurement offorces) are above 40 times the wheel rotational frequency used in the measurement. For special types ofinstrumentation that are matched to machine resonance
19、s, this requirement may be waived. The drum andwheel spindles are to be rigidly supported with no lash in radial, axial, or tractive directions.The structure and rims are to accept tires of 559 to 914 mm (22 to 36 in) in diameter and 127 to 330 mm (5 to13 in) in section width. The equipment is to be
20、 capable of rotating tires at a speed in the range of 15 to 60 rpmduring the measuring operation and with the option of 300 to 400 rpm for stabilization before measurement.The design should be based on a maximum force between tire and drum of 8.9 kN (2000 lb) in the radialdirection, 2.22 kN (500 lb)
21、 laterally, and 2.22 kN (500 lb) in the tractive direction.4.3 Drum, Axles, and RimsThe drum is to be standardized at 854.1 mm 2.5 mm (33.625 in 0.100 in) indiameter. The total indicated runout of this member as measured at a reference band is to be less than0.025 mm (0.001 in). The maximum acceptab
22、le unbalance is 0.113 Nm (1 in-lb). The drum should feature ahigh-friction, textured surface, such as provided by knurling, sprayed tungsten carbide, adhered tungstencarbide crystals, etc. The surface texturing, however, must be sufficiently uniform so that the average radius ofthe drum per 51 mm (2
23、.0 in) of circumference meets the specifications for runout. The parallelism of the rimaxis and the drum axis while under 8.9 kN (2000 lb) of radial load and 445 N (100 lb) of lateral load should bewithin a tolerance of one part in 4000 (0.25 mm/m (0.003 in/ft).SAE J332 Revised NOV2002-3-The machine
24、 should be adaptable for accommodating different sizes of tires. This is best accomplishedthrough interchangeable rims. Rims for force variation measurement should be based on the recommendedcontour of the Tire and Rim Association for that size and type tire. Some modifications to this contour may b
25、erequired to facilitate mounting, dismounting, and proper seating of the bead for repeatable data. Thesemodifications will depend upon tire bead dimensions, mounting technique, and warm-up procedure. The innerspacing between flanges (for both passenger cars and light truck tires) should be the Tire
26、and Rim Associationdesign rim width 13 mm (0.5 in).These rims are to have a total indicated runout at the bead seats of less than 0.025 mm (0.001 in). Thislimitation refers to both radial and axial directions and pertains to rims as installed with normal piloting on themachine. The design of the rim
27、s should enable rapid mounting and dismounting of the tires. The rims are tobe sufficiently rigid to insure that deflection in any direction at the bead seat operating under loads is less than0.127 mm (0.005 in).5. Measuring System A mechanical system of appropriate design which includes transducers
28、 for thedevelopment of output signals is required to isolate and detect the aforementioned components of forcevariation and mean force. The transducers may be either between the structure supporting the tire and thetire, or between the structure supporting the drum and the drum. For either alternati
29、ve, the precaution shouldbe observed that the torque for providing rotation does not pass through the spindle at which the transducersare located.In accordance with the resonance requirements already indicated, the minimum natural frequency of the forcemeasuring system shall be at least 40 times the
30、 frequency of tire rotation that prevails during measurement.The resolution of force components by the measuring system shall be 4.4 N (1 lb) or less, including the effectsof static friction. The deviations from true values of force within the 445 N (100 lb) range of excursion shall beless than 4.4
31、N (1 lb).Errors in measurement of lateral force due to mechanical interaction from the radial force shall be less than0.1% of the radial force. Spurious components of radial force due to mechanical interaction from the lateralforce shall be less than 1% of the lateral force. Removal of interaction,
32、where required, shall be accomplishedin the signal processing circuitry or other instrumentation.The mechanical isolation of the machine or of the force measuring system shall be such that vibratoryinterferences from exterior and internal sources will not exceed 2.2 N (0.5 lb) root mean square in an
33、y of theforce component measuring systems.A matching calibration system is required for use with the force measuring system. The resolution of the loadsapplied by the calibrating system should be within 1.1 N (0.25 lb) for both lateral and tractive forcecomponents. The calibration system for the mea
34、n radial force measurement requires tare loads up to 8.9 kN(2000 lb) with resolutions of applied force of 44 N (10 lb). There should as well be an additional provision forcalibrating radial force variations from the tare load with forces up to 890 N (200 lb) and with resolutions ofapplied force with
35、in 1.1 N (0.25 lb).The measuring system shall contain a position marker to indicate the angular orientation of the tire relative tothe force signals that it produces.6. InstrumentationInstrumentation shall be provided to convert the variations in force components into analogsignals or into a numeric
36、al form suitable for engineering evaluation. This subsystem shall have suchproperties as to enable the uniformity testing machine to produce data within the specifications under theparagraph on Ranges and Accuracies of the Uniformity Testing Machine.The instrumentation should contain an integral mea
37、ns for testing (both statically and dynamically) its scalingand the interaction among channels.SAE J332 Revised NOV2002-4-6.1 Optional InstrumentationAccording to the usage intended several kinds of auxiliary instrumentation maybe provided with the Uniformity Measuring Machine. Two types that have f
38、ound considerable application arelisted as follows:a. Equipment for indicating peak-to-peak measurements and time averages of components of forcevariations.b. Equipment for measuring the amplitude and phase of the first ten harmonics of components of forcevariation. Phase is designated by the angula
39、r orientation of the rotating tire.7. Ranges and Accuracies of the Uniformity Testing Machine7.1 The machine is to provide output signals corresponding to the following ranges of force components:Mean radial load from 0 to 8.9 kN (0 to +2000 lb).Mean lateral force from 890 to +890 N (200 to +200 lb)
40、.Mean tractive force from 890 to +890 N (200 to +200 lb).Radial force variation from 445 to +445 N (100 to +100 lb).Lateral force variations from 445 to +445 N (100 to +100 lb).Tractive force variations from 445 to +445 N (100 to +100 lb).7.2 The complete machine shall be capable of measuring the va
41、rious force variations to within 2.2 N (0.5 lb) andto measure and set the mean radial force to within 5% of the prescribed value.7.3 Error in the measurement of force components due to the presence of other components of force (applied inother transducer channels) shall be less than 0.5% of full-sca
42、le reading of that channel.7.4 Output impedances shall be at the 600 level or less.7.5 Random errors in force measurements for any varying component shall be less than 4.4 N (1 lb) over thefrequency range from zero to the tenth harmonic of wheel rotation frequency.7.6 The frequency response of the t
43、otal measurement relative to input force shall be within 2% of the staticresponse at 445 N (100 lb) peak-to-peak of excitation force from the first to the tenth harmonic. The maximumallowable phase shift for frequency contents over this range is given by the quantity . It is required that beless tha
44、n 6, where is defined as phase shift in degrees of the signal frequency divided by the harmonicnumber of the frequency.8. Operating ScheduleThe schedule consists of the following key steps. Numerous auxiliary actions are notlisted.a. Tire mounting and inflation of the tire.b. A warm-up procedure whi
45、ch insures that distortions in the structure of the tire due to packaging andshipping are reduced to an acceptable level.c. The adjustment of the inflation pressure and the rotation of the tire at a constant angular velocity formeasurement.d. The adjustment of the axle-to-axle spacing of the rolling
46、 tire and drum to provide a predeterminedvalue of mean radial force.e. The measurement of the force components generated by rotating the tire.f. Where desired, the reversal of the direction of rotation and a repeated measurement of forcecomponents.SAE J332 Revised NOV2002-5-8.1 Precautions and Condi
47、tionsSpecific precautions and conditions that are recommended for the variousphase of operation are as follows:a. Care should be taken that both the tire and drum are free of surface contamination such as labels, oil,and dirt.b. Proper bead seating should be assured by use of a suitable lubricant an
48、d/or low friction bead surface,by suitable mounting methods, and by the subsequent warm-up procedure.c. A suitable warm-up procedure is required to insure that local distortions due to packaging and shippinghave been removed from the tire. This procedure consists of rolling the tire against the drum
49、 at somecombination of speed, inflation pressure, mean radial load, and running time. The particularcombination of conditions has to be established for each plant or location and typical state of the tires.The warm-up procedure is considered sufficient when it guarantees that the change in peak-to-peakforce variations for a group of 20 tires selected at random when run against the drum for an additionaltime period at the “nominal” conditions of load and inflation specified for that size and type tire is lessthan 5.67 N (1.5 lb) from the value mea
