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.TO PLACE A DOCUMENT ORDER: (724) 776-4970 FAX: (724) 776-0790SAE WEB ADDRESS http:/www.s
3、ae.orgCopyright 2001 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001RECOMMENDEDPRACTICESubmitted for recognition as an American National StandardJ1731REV.JUN2001Issued 1995-06Revised 2001-06Superseding J1731 J
4、UN1995Pilot Bearings for Truck and Bus Applications1. ScopeThis SAE Recommended Practice describes STANDARD-DUTY and EXTREME-DUTY Pilot Bearingrequirements and sizes for class 6, 7, and 8 on-highway trucks and buses that use diesel engines and manualtransmissions. The recommendations may apply to a
5、wide range of other pilot-bearing applications, such asagricultural, industrial, and construction equipment.1.1 PurposeThis document establishes standards for pilot-bearing construction, tolerances, installationdimensions, and operating characteristics. It is intended to standardize installation dim
6、ensions for engine andtransmission manufacturers, and identify minimum operating characteristics to ensure satisfactory bearing lifein pilot-bearing application environment.2. ReferencesThere are no referenced publications specified herein.3. General InformationThis document applies to Pilot Bearing
7、s used to locate and support the transmissioninput shaft to the engine crankshaft rotational center. These bearings are usually located in the engineflywheel, and the pilot diameter of the transmission input shaft slides into them upon installation of thetransmission to the engine.Pilot Bearings des
8、cribed in this document are Conrad type ball bearings and generally conform to normal ballbearing construction and dimensioning practices, except as specified in this document.The maximum operating temperatures shown in this document reflect temperature ratings for the variousmaterials involved. It
9、is generally agreed that peak temperatures will be short-term events related to dutycycle. Normal continuous operating temperatures will be significantly lower. Continuous operation atmaximum temperature rating may result in shortened bearing life. Consult bearing manufacturer forapplication approva
10、l.3.1 Standard-Duty Pilot BearingsSTANDARD-DUTY Pilot Bearings are recommended for applications wherethe maximum bearing temperature will not exceed 149 C (300 F).3.2 Extreme-Duty Pilot Bearings3.2.1 EXTREME-DUTY Pilot Bearings are recommended for applications where maximum bearing temperaturesexcee
11、d 149 C (300 F) but do not exceed 200 C (392 F).3.2.2 EXTREME-DUTY Pilot Bearings are suitable for use for standard-duty applications.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE J1731 Revised J
12、UN2001-2-3.3 Operating Characteristics3.3.1 OPERATING TEMPERATUREStandard-Duty Pilot Bearings will operate in a temperature range of 40 to+149 C (40 to +300 F). Extreme-Duty Pilot Bearings will operate in a temperature range of 40 to 200 C(40 to 392 F). All materials shall be capable of operation th
13、roughout these respective temperature ranges,and be compatible with each other within these temperature ranges.Extreme-Duty Pilot Bearings will require special heat stabilization of the steel elements to ensurecompatibility with the higher operating temperature.3.3.2 BEARING INTERNAL CLEARANCEAll Pi
14、lot Bearings shall have a C5 internal clearance to ensure that nopreload exists within the bearing throughout the temperature range and dimensional fits.3.3.3 SEALINGIt is required that pilot bearings be sealed on both sides to prevent the ingestion of contaminantsand to provide retention of the bea
15、ring lubricant. The seals must be capable of operating effectivelythroughout the established temperature ranges and must be compatible with the lubricant. It is generallyaccepted that fluorocarbon (Viton) seals, or equivalent, are required for both Standard-Duty and Extreme-Duty applications.3.3.4 B
16、EARING LUBRICANTThe pilot bearing should be permanently lubricated with a grease that is capable ofoperating throughout the required temperature range, and is compatible with the oil seal materials.Premium-quality, high-temperature, petroleum-based lubricants may be satisfactory for Standard-Duty Pi
17、lotBearings. Extreme-Duty Pilot Bearings require synthetic-based grease due to their higher operatingtemperature requirements.The bearing shall be packed with a sufficient quantity of appropriate lubricant to ensure adequate lubrication,but shall not be overfilled to the point that lubricant will mi
18、grate out of the bearing or overcome the seals. It isgenerally accepted that a 30% fill of the actual sealed volume of the bearing is desired.3.3.5 MAXIMUM ROTATING TORQUEAll pilot bearings require that the maximum torque to rotate the outer racerelative to the inner race not exceed 0.20 Nm (1.77 in
19、-lb).Torque shall be measured at ambient temperature 22 C 6 C (72 F 11 F) while rotating the inner raceat 600 RPM with the outer race restrained. Bearing should be operated at 600 RPM for 20 min prior tomeasurement of maximum torque. Test should be run with no radial load, and with no interference f
20、it to thetest fixture that would influence internal bearing clearance.Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE J1731 Revised JUN2001-3-3.4 Pilot-Bearing Sizes and TolerancesSee Figure 1.FIGU
21、RE 1PILOT-BEARING SIZES AND TOLERANCES4. Notes4.1 Marginal IndiciaThe change bar (l) located in the left margin is for the convenience of the user in locatingareas where technical revisions have been made to the previous issue of the report. An (R) symbol to the leftof the document title indicates a
22、 complete revision of the report.PREPARED BY THE SAE TRUCK AND BUS CLUTCH SUBCOMMITTEEOF THE SAE TRUCK AND BUS POWERTRAIN COMMITTEECopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-SAE J1731 Revised JUN2
23、001RationaleNot applicable.Relationship of SAE Standard to ISO StandardNot applicable.ApplicationThis SAE Recommended Practice describes STANDARD-DUTY and EXTREME-DUTY PilotBearing requirements and sizes for class 6, 7, and 8 on-highway trucks and busses that use dieselengines and manual transmissio
24、ns. The recommendations may apply to a wide range of other pilot-bearing applications, such as agricultural, industrial, and construction equipment.Reference SectionThere are no referenced publications specified herein.Developed by the SAE Truck and Bus Clutch SubcommitteeSponsored by the SAE Truck and Bus Powertrain CommitteeCopyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-
