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.QUESTIONS REGARDING THIS DOCUMENT: (412) 772-8512 FAX: (412) 776-0243TO PLACE A DOCUMENT
3、 ORDER; (412) 776-4970 FAX: (412) 776-0790SAE WEB ADDRESS http:/www.sae.orgCopyright 1997 Society of Automotive Engineers, Inc.All rights reserved. Printed in U.S.A.SURFACEVEHICLE400 Commonwealth Drive, Warrendale, PA 15096-0001STANDARDSubmitted for recognition as an American National StandardJ1977I
4、SSUEDAPR97Issued 1997-04BRAKING PERFORMANCERUBBER-TIRED, SELF-PROPELLED CRANES1. ScopeThis SAE Standard applies to machines as defined in Appendix A. Some of these machines cantravel on-highway, but function primarily off-highway.1.1 PurposeThis document specifies braking system performance and test
5、 criteria for rubber-tired cranes asdefined in the scope and is a guideline to enable uniform evaluation of the braking capability of thesemachines. Service, secondary, and parking brake systems are included.2. References2.1 Related PublicationsThe following publications are provided for information
6、 purposes only and are not arequired part of this document.2.1.1 SAE PUBLICATIONSAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001.SAE J786aBrake System Road Test CodeTruck, Bus, and Combination of VehiclesSAE J1473Brake PerformanceRubber-Tired Earthmoving Machines2.1.2 ISO PUBLI
7、CATIONAvailable from ANSI, 11 West 42nd Street, New York, NY 10036-8002.ISO3450-1985Earthmoving machineryWheeled machinesPerformance requirements and testprocedures for braking systems3. Definitions3.1 Rubber-Tired CranesA rubber-tired machine consisting of a chassis designed for mounting anupperstr
8、ucture and its attachments as identified in Appendix A.3.2 Braking SystemsAll the elements which participate in stopping and holding the machine. Such systemsconsist of a supply, control, means of power transmission, and the brake.3.2.1 SERVICE BRAKE SYSTEMThe primary system used for stopping and ho
9、lding the machine.3.2.2 SECONDARY BRAKE SYSTEMThe system used for stopping the machine in the event of any single failure inthe service brake system.SAE J1977 Issued APR97-2-3.2.3 PARKING BRAKE SYSTEMThe system used to hold a stopped machine in a stationary position for anextended period of time.3.2
10、.4 BRAKE SYSTEM COMPONENTS3.2.4.1 SupplyA pump or compressor in combination with a reservoir to provide the energy for actuation of theservice and secondary brake.3.2.4.2 ControlThe component(s) activated by the operator to cause a force to be transmitted to the brake(s).3.2.4.3 Power Transmission M
11、eansAll of the elements between the control and the brake(s) which connect(s)them (it) functionally.3.2.4.4 Brake(s)The component(s) which directly applies (apply) a force to oppose movement of the machine.3.2.4.5 RetarderAn energy absorption device normally used to control machine speed while desce
12、nding grades.3.3 Common ComponentA component which performs a function in two or more braking systems.3.4 Machine MassOperating mass of the machine up to that mass which includes the heaviest combination ofequipment approved by the manufacturer of the machine, an operator of 75 kg, and with the mach
13、ine fullyfueled and serviced.3.5 Stopping DistanceThe distance traveled by the machine from the point on the test course at which themachine brake control actuation initial movement begins to the point where the machine is fully stopped.3.6 MEAN DecelerationThe average rate of change of velocity of
14、the machine, from the instant the brakecontrol actuation begins until a full stop is achieved. It may be determined from Equation 1:(Eq. 1)where:a = mean deceleration in m/s2V = velocity in m/s of the machine immediately prior to brake control actuationL = stopping distance in meters3.7 BurnishA pro
15、cedure to condition the frictional surfaces of the machine brake(s) to provide good lining todrum contact.3.8 Brake System PressureThe gas or hydraulic pressure available at the brake actuation mechanism.3.9 Test CourseThe surface upon which the test is conducted.3.10 Cold BrakesBrakes shall be cons
16、idered to be “cold” if any of the following conditions are met:3.10.1 The brakes have not been actuated in the previous 1 h.3.10.2 The brakes have been cooled to 100 C or less when measured on the brake disc or on the outside of thebrake drum.3.10.3 In case of totally enclosed brakes, including oil-
17、immersed brakes, the temperature measured on the outsideof the housing is below 50 C, or within the manufacturers specifications.a = V2 2LSAE J1977 Issued APR97-3-4. Instrumentation4.1 A means to measure and record test parameters within the specified accuracy, see Table 1:5. General Brake Requireme
18、nts5.1 Required Brake RequirementsAll machines shall be equipped with:5.1.1 A service braking system5.1.2 A secondary braking system5.1.3 A parking system5.2 Common ComponentsBraking systems may use common components; however, in the event of a failure ofany single component, other than a tire, the
19、braking systems shall provide machine stopping capability meetingthe secondary braking system performance requirements specified in the appropriate table.5.3 Service Braking SystemAll machines shall meet the service braking performance requirements specified inthe appropriate table (see 7.6). All ma
20、chines shall have braked wheels on all axles and wheels except formachines that fit the description of Class 3, which shall have at least two braked wheels on the one axle.5.4 Secondary Braking SystemAll machines shall meet the secondary braking performance requirementsspecified in the appropriate t
21、able (see 7.6).5.5 Parking Brake SystemAfter being applied, this system shall not be dependent upon an exhaustible energysource. The parking brake system may use common components with other braking systems provided therequirements of 7.5.2 and 7.5.3 are met.5.6 Warning Device (Stored Energy Sources
22、)If stored energy is used to apply the service braking system, thatsystem shall be equipped with a warning device which activates before system energy drops below the greaterof 50% of the manufacturers specified maximum operating energy level or the level required to meet thesecondary stopping requi
23、rements, whichever is higher. The warning device shall readily attract the operatorsattention by providing a continuing visual or audible warning. Gauges indicating pressure or vacuum do notmeet this requirement.5.7 Reservoirs (Air System)The combined volume of all service and supply reservoirs shal
24、l be at least twelvetimes the combined volume of all service brake chambers at maximum travel of the pistons of diaphragms.5.8 Air Compressors (Air System)An air compressor of sufficient capacity to increase air pressure in thesupply and service reservoirs from 85 psi to 100 psi in 25 s with the min
25、imum required reservoir capacity andthe engine operating at the vehicle manufacturers maximum recommended rpm.TABLE 1TEST PARAMETERSParameter Instrument AccuracyBraking System Pressure 3.0%Machine Speed 3.0%Machine Mass 2.5%Stopping Distance 1.0%Brake Control Actuating Force 3.0%Grade 1.0%SAE J1977
26、Issued APR97-4-6. Test Conditions6.1 The machine manufacturers precautions shall be observed while conducting performance tests.6.2 The test course surface shall consist of a hard, dry surface with a well compacted base. The test course shallnot have more than 3% grade at right angles to the directi
27、on of travel. Grade in the direction of travel shall notexceed 1.0%. The approach to the test course shall be of sufficient length, smoothness, and uniformity ofgrade to ensure reaching the required machine speed before the brakes are actuated.6.3 Machine mass shall be as defined in 3.4 at the manuf
28、acturers specified axle distribution.6.4 All parameters related to braking systems shall be within the machine manufacturers specifications, i.e., tiresize and pressure, brake adjustment, warning device actuation point, etc. All brakes system pressures shall bewithin the machine manufacturers specif
29、ication range. No manual adjustment(s) shall be made to the brakesystem during any one performance test.6.5 When the machine transmission provides a selection of gear ratios, the stopping tests shall be conducted withthe transmission in the gear commensurate with the test speed specified. The powert
30、rain may be disengagedimmediately prior to completing the stop but shall not downshift during the test unless done automatically.6.6 Retarders shall not be used during the service brake system tests. Retarders may be used during thesecondary brake system tests as specified in 7.6.2.4.6.7 The upperst
31、ructure and other equipment shall be carried in the transport position as recommended by themanufacturer.6.8 Burnishing (conditioning) of brakes before testing is recommended. Follow burnish procedure in SAE J786a.6.9 Immediately prior to a test, the machine shall be operated until the engine, trans
32、mission, brakes, and machinefluid are at normal operating temperature. This is generally 66 to 93 C.6.10 Machine speed shall be measured immediately prior to the brake control being applied.6.11 As a minimum, all data required by the test report (Section 8) shall be recorded and reported.7. Performa
33、nce Tests7.1 Braking Systems Controls7.1.1 Control forces needed to meet the required brake performance for the systems defined in 3.2, shall notexceed the values in Table 2.7.1.2 All braking system controls shall be capable of being applied by a person seated in the drivers seat. Thesecondary and p
34、arking brake system(s) control(s) shall be arranged so that they cannot be released from thedrivers seat after any application unless immediate reapplication can be made from the drivers seat.SAE J1977 Issued APR97-5-7.2 Service Brake System Recovery Capacity (Stored Energy System)The engine speed c
35、ontrol (throttle)shall be set to obtain maximum engine rotational speed (rpm). The service brake system shall have thecapability to deliver at least 70% of the pressure measured during the first brake application after the servicebrakes have been fully applied 12 times at a rate of 4 applications pe
36、r minute.7.3 Secondary Brake System Capacity (Stored Energy System)If the service brake system stored energyreservoir(s) is (are) used to apply the secondary braking system, then, with the energy source disconnectedand the machine stationary, the capacity of the service brake system reservoir(s) sha
37、ll be such that the energyremaining in the reservoir(s) after five full service brake applications is not less than that required to meet thesecondary stopping requirements in 7.6.2.4. The secondary brake system for Class 1 and 2 shall be capableof modulation by means of the service brake control.7.
38、4 Warning Device (Stored Energy System)The service brake system energy shall be reduced by anysuitable means. The warning device (see 5.6) shall activate before system energy drops below the greater of50% of the manufacturers specified maximum stored energy level or the stored energy level required
39、to meetthe secondary stopping requirements (see 7.6.2.4). The warning device shall activate prior to any automaticapplication of a secondary braking system.7.5 Holding PerformanceAll machines shall be tested in both the forward and reverse directions on a testcourse as described in 6.2.7.5.1 The ser
40、vice braking system shall have the capability of holding the machine stationary on a 25% grade.7.5.2 The parking brake system shall be capable of holding the machine stationary on a 15% grade. Thepowertrain(s) shall be disengaged.7.5.3 If the tests in 7.5.1 and 7.5.2 are impractical, the tests may b
41、e carried out either:a. On a tilt platform (a skid-resistant surface that may be inclined), orb. By applying a pulling force to the stationary machine with the brake set and with the transmission inneutral on a test course as described in 6.2, the pulling force shall be applied horizontally near the
42、ground to achieve a minimum force equivalent to the grades specified in 7.5.1 and 7.5.2. Theequivalent force in Newtons is 2.38 times machine mass force in kilograms for a 25% grade and 1.46times machine mass in kilograms for a 15% grade (see 6.3).TABLE 2BRAKING CONTROL FORCESControl Type ForceFinge
43、r Grasp(Flip levels and switches)20 NHand GraspUpward 400 NFore-aft 300 NSideways 300 NFoot Pedal (leg control) 700 NFoot Treadle (ankle control) 350 NSAE J1977 Issued APR97-6-7.6 Stopping Performance7.6.1 TEST CONDITIONSa. Brake performance shall be tested from a machine speed not less than 32 km/h
44、 3 km/h and no morethan 48 km/h 3 km/h. Use the machines maximum level surface speed if less than 32 km/h.b. Tests shall be performed in accordance with the test conditions specified in Section 6.7.6.2 COLD TESTS7.6.2.1 Beginning with cold brakes (see 3.10 and 6.9), service and secondary braking sys
45、tem stopping distancetests shall be conducted two times while traveling forward, once in each direction of the test course, with atleast 10 min between stops.7.6.2.2 Stopping distance and machine speed used in reporting the test results shall be the average of the twotests (once in each direction of
46、 the test course) described in 7.6.2.1.7.6.2.3 The service braking system (see 5.3) shall stop the machine within the stopping distance specified inTable 3 or 4.7.6.2.4 The secondary braking system (see 5.4) shall stop the machine within the distance specified in Table 3 or4. Auxiliary retarders sha
47、ll not be used in the test unless the retarder is simultaneously actuated by theapplicable brake system control.7.6.3 HEAT FADE TEST7.6.3.1 Machines shall be tested as stated in 7.6.1.TABLE 3STOPPING PERFORMANCECLASS 1Machine Mass(kg)Maximum StoppingDistance in Meters (m)Service BrakeSystem(1)1. whe
48、re: V = Machine Speed (km/h)Maximum StoppingDistance in Meters (m)Secondary BrakeSystem(1)up to 32 000 V2 / 85 + 0.1 (32 V) V2 / 35 + 0.1 (32 V)over 32 000 V2 / 72 + 0.1 (32 V) V2 / 30 + 0.1 (32 V)TABLE 4STOPPING PERFORMANCECLASS 2 AND 3Machine Mass(kg)Maximum StoppingDistance in Meters (m)Service B
49、rakeSystem(1)1. where: V = Machine Speed (km/h)Maximum StoppingDistance in Meters (m)Secondary BrakeSystem(1)up to 23 000 V2 / 63 + 0.1 (32 V) V2 / 24 + 0.1 (32 V)over 23 000 V2 / 57 + 0.1 (32 V) V2 / 23 + 0.1 (32 V)SAE J1977 Issued APR97-7-7.6.3.2 The service brakes shall be applied and released to complete four consecutive stops at or as near aspossible to the machines maximum deceleration without sliding tires. After each stop, the initial test speedshall be regained as quickly as possible using max
