1、 WORLDWIDE ENGINEERING STANDARDS Test Procedure GMW14871 Brake Fitting Torque Copyright 2012 General Motors Company All Rights Reserved November 2012 Originating Department: North American Engineering Standards Page 1 of 16 1 Scope Note: Nothing in this standard supercedes applicable laws and regula
2、tions. Note: In the event of conflict between the English and domestic language, the English language shall take precedence. 1.1 Purpose. The purpose of this test is to provide data to help establish a tightening specification for brake tube nuts. 1.2 Foreword. This procedure is concerned with the i
3、nitial tightening of threaded brake fittings. It does not address the issues of loosening and retightening of the fitting or the properties of sealant compounds applied to the threads. 1.3 Applicability. This procedure applies to all threaded brake fittings. 2 References Note: Only the latest approv
4、ed standards are applicable unless otherwise specified. 2.1 External Standards/Specifications. None 2.2 GM Standards/Specifications. GMW15569 2.3 Additional References. CG583 Validation Test and Vehicle Review 3 Resources 3.1 Facilities. GM Approved Laboratory or location for this test procedure. 3.
5、2 Equipment. 3.2.1 Appropriate fixture, bedplate or slotted table. 3.2.2 Leak detection solution (“The Leak Detective” Low Temp DL-11, MIL-L-25567D Type II) or equivalent and applicator. 3.2.3 SPS Sensor I digital torque wrench or equivalent. 3.2.4 Flare nut crows foot (open end) wrench, sockets and
6、 adapters. 3.2.5 Air pressure gauges/transducers and fittings. 3.2.6 Torque angle transducer capable of measuring ultimate torque. 3.2.7 Data acquisition system capable of: collecting torque angle data at a sampling rate of at least 500 Hz, plotting torque angle data at various scales, and identifyi
7、ng torque and angle data for each point on the curve. 3.2.8 Electric tube nut power tool capable of operating at 250 RPM, downshifting to 50 RPM to a final torque and a control unit capable of displaying torque and angle values. 3.2.9 Power tool with a free spinning speed of 100 RPM 50 RPM and capab
8、le of developing Ultimate Torque. 3.2.10 Pin gages. Note: All instrumentation is to be calibrated. Record instrumentation details and date of calibration. 3.3 Test Vehicle/Test Piece. 3.3.1 The recommended number of test samples is: Copyright General Motors Company Provided by IHS under license with
9、 General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14871 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 2 of 16 Six samples for Test No. 1 (Torque Angle Evaluation). Thirty samp
10、les for Test No. 2 (Hand Torque to Seal and Leakage). Unspecified number of samples for Test No. 3 (Through-Hole Reduction Measurement). Thirty samples for Test No. 4 (Torque to Target Through-Hole Reduction Measurement and Seal) or an alternative number of test samples specified by the Fastener/Des
11、ign Release or Test Engineer. 3.3.2 Test material will be to production specifications or as specified by the Fastener/Design Release or Test Engineer per CG583 Validation Test and Vehicle Review. 3.4 Test Time. Calendar time: 2 to 10 days Test hours: 16 to 80 hours Coordination hours: 8 hours 3.5 T
12、est Required Information. Fastener/Design Release or Test Engineer is to supply and record all data requested on Test Required Information Worksheet or similar (reference Appendix B). 3.6 Personnel/Skills. Test Technician shall be qualified on the basis of appropriate education, training, experience
13、, and/or demonstrated skills. 4 Procedure 4.1 Preparation. 4.1.1 Fittings and associated components should be reviewed for conformity to specifications or as directed by the Fastener/Design Release or Test Engineer for each associated component (tube nut, tube, port). 4.1.2 Any modifications to part
14、s, not specifically requested in the test request, that may affect test results, are to be documented in the test notes. All test configurations, parts and noted deviations to be approved prior to executing test. 4.1.3 Unless otherwise specified, components will be “as received” clean and dry. Blow
15、out any foreign material that has fallen into the port. 4.1.4 Torque shall be applied to the externally threaded tube nut unless otherwise directed by the Fastener/Design Release or Test Engineer. 4.1.5 Each tube nut, tube, or port shall not be reused unless specified by the Fastener/Design Release
16、or Test Engineer. 4.1.6 Set the data acquisition system to collect data at a sampling rate of at least 500 Hz. 4.2 Conditions. 4.2.1 Environmental Conditions. Measurements are to be taken at room ambient temperature conditions, 20 C to 25 C (68 F to 73 F). 4.2.2 Test Conditions. Deviations from the
17、requirements of this standard shall have been agreed upon. Such requirements shall be specified on component drawings, test certificates, reports, etc. 4.3 Instructions. 4.3.1 Test No. 1: Torque Angle Evaluation. 4.3.1.1 Secure component (master cylinder, anti-lock braking system (ABS) unit, etc.) i
18、n a fixture/vise. 4.3.1.2 Measure and record port through-hole diameter for inverted flares and the tube flare through-hole diameter for International Organization for Standardization (ISO) mushroom flares using pin gages. 4.3.1.3 Cut tube to a length that can be used with a deep socket. If necessar
19、y, use a spacer in a deep socket to prevent the socket from contacting the port housing during tightening. 4.3.1.4 Obtain approval for the setup from the requestor unless otherwise specified. 4.3.1.5 Take photograph or digital image of test configuration. 4.3.1.6 Measure and document tool free spinn
20、ing speed. Free spinning speed to be 100 RPM 50 RPM. 4.3.1.7 Align tool and torque transducer to prevent side loading. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLD
21、WIDE ENGINEERING STANDARDS GMW14871 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 3 of 16 4.3.1.8 Dynamically tighten each sample to failure, using a power tool with no down shift, and a torque angle transducer (see Appendix A, Figure A1). Record torque and angle. Docu
22、ment the Ultimate Torque and record the failure mode. Disassemble if required. 4.3.1.9 Measure and record port through-hole diameter for inverted flares and the tube flare through-hole diameter for ISO mushroom flares using pin gages (see Figure A2). If necessary, cut off the tube next to the tube n
23、ut to measure the through-hole diameter. Report through-hole size to the Fastener/Design Release or Test Engineer to determine if Test No. 3 is required. Test No. 3 is not required if the final through-hole size is larger than the minimum required for system fluid flow. 4.3.1.10 Review parts with th
24、e Fastener/Design Release or Test Engineer. 4.3.1.11 Conduct Test No. 3 if specified by the requestor. 4.3.2 Test No. 2: Hand Torque to Seal and Leakage. 4.3.2.1 Secure component (master cylinder, Anti-lock Braking System (ABS) unit, etc.) in a fixture/vise. 4.3.2.2 Hand thread the test parts togeth
25、er and pre-torque the fittings to 2.0 Nm using a digital hand torque wrench (see Figure A3). 4.3.2.3 Obtain approval for the setup from the requestor unless otherwise specified. 4.3.2.4 Pressurize the connection to 620 kPa (90 psi) 10% with air. Apply leak detection solution to the fitting. Brush or
26、 siphon all bubbles off of the fitting to confirm whether leakage occurs. Maintain this pressure for one minute. Recurrence of any bubble indicates leakage. 4.3.2.5 If the fitting does not leak, record the seal torque. 4.3.2.6 If the fitting leaks, use a digital torque wrench to slightly tighten the
27、 fitting in 1 Nm increments until the leakage stops. Record the seal torque. 4.3.2.7 After joint seals, continue to tighten the fitting as follows. 4.3.2.7.1 For an ISO mushroom type flare, tighten the fitting in 5 Nm increments until leakage occurs or other failure occurs. 4.3.2.7.2 For an inverted
28、 flare fitting, tighten the first 10 samples in 5 Nm increments until leakage or other failure. Tighten the remaining samples in a slow continuous motion until failure occurs. 4.3.2.8 Record the leakage torque or failure torque and the failure mode. 4.3.3 Test No. 3: Through-Hole Reduction Measureme
29、nt (When Specified). 4.3.3.1 The quantity of test pieces is as specified by the Fastener/Design Release or Test Engineer. 4.3.3.2 Measure and record port through-hole diameter for inverted flares and the tube flare through-hole diameter for ISO mushroom flares using pin gages. See Figure 1. Figure 1
30、: Port Through Hole 4.3.3.3 Hand thread the test parts together two or three threads. Tighten the nut with the electric tube nut power tool to the torque, RPM and shift requirements as specified by the Fastener/Design Release or Test Engineer. Tighten first sample(s) to 20 Nm or as specified by the
31、Fastener/Design Release or Test Engineer. 4.3.3.4 Record tool (dynamic) torque. 4.3.3.5 Measure and record audit (static) torque per test procedure GMW15569. 4.3.3.6 Disassemble the attachment, measure and record the component through-hole diameter using pin gages. Copyright General Motors Company P
32、rovided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STANDARDS GMW14871 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 4 of 16 4.3.3.7 Repeat 4.3.3.2 through 4
33、.3.3.6 for additional torque levels in 5 Nm increments or as requested by the Fastener/Design Release or Test Engineer. 4.3.4 Test No. 4: Torque to Target, Through-Hole Reduction Measurement and Seal. 4.3.4.1 Obtain the target torque range from the Fastener/Design Release or Test Engineer. 4.3.4.2 M
34、easure and record port through-hole diameter for inverted flares and the tube flare through-hole diameter for ISO mushroom flares using pin gages. 4.3.4.3 Hand-thread test parts together two or three threads. 4.3.4.4 Secure the tube so it cannot rotate during tightening. Rotation can be prevented by
35、 bending the tube 90 degrees and positioning it against a stop, or by using a 90 degree fitting and positioning the fitting against a stop. 4.3.4.5 Use the electric tube nut tool to tighten the tube nuts (see Figure A4). Program the electric tube nut tool to tighten the tube nut to 50% of the target
36、 torque at 250 RPM, then downshift to 50 RPM to the target torque. 4.3.4.6 Obtain approval for the setup from the requestor unless otherwise specified. 4.3.4.7 Dynamically tighten the fittings to the low end of the torque range. 4.3.4.8 Record tool (dynamic) torque. 4.3.4.9 Pressurize the connection
37、 to 620 kPa (90 psi) 10% air or as specified by the requestor. Apply leak detection solution to the fitting (see Figure A5). Maintain this pressure for one minute and check for leaks. 4.3.4.10 Record whether the fitting leaked. 4.3.4.11 If the fittings leak, contact the Fastener/Design Release or Te
38、st Engineer. 4.3.4.12 If no leak occurs, measure the audit torque per test procedure GMW15569 using a digital hand torque wrench. Record the audit torque. 4.3.4.13 Measure and record the port through-hole diameter for inverted flares and the tube flare through-hole diameter for ISO mushroom flares u
39、sing pin gages. If necessary, disassemble the attachment or cut off the tube near the tube nut to make the measurements. 4.3.4.14 Repeat 4.3.4.2 through 4.3.4.13 for the remaining samples unless otherwise specified by requestor. 5 Data 5.1 Calculations. Not applicable. 5.2 Interpretation of Results.
40、 5.2.1 Summary of Results. Required. 5.2.1.1 Test file log to be on Test Log Sheet or similar (reference Appendix C). 5.2.1.2 Provide detail of failure modes consisting of, but not limited to, fastener fracture, component fracture, component distortion, hex round off, or internal or external thread
41、stripping (if applicable). 5.2.1.3 Test incidents to be recorded on Test Summary Sheet or similar (reference Appendix D). 5.2.1.4 Test data summarization to be on Test Data Sheets or similar (reference Appendices E through H). 5.2.1.5 Perform Statistical Analysis of Seal. Torque, Ultimate Torque, Ma
42、ximum Allowable Torque, Audit Torque including the average, minimum, maximum, standard deviation and average 3 standard deviations. 5.2.1.6 Required Plots. Make individual plots of torque (Y axis) vs. angle (X axis) for each sample in Test No. 1, and a multiple plot with the curves aligned to Zero A
43、ngle Reference Torque just above the maximum seat torque. Scale the plots from zero to the maximum value in whole numbers to capture the complete event. 5.3 Test Documentation. 5.3.1 Photograph the test setup and test samples. 5.3.2 Identify the failure mode for each joint tested. 5.3.3 Report all e
44、quipment serial numbers/tool characteristics. 5.3.4 Record any part deviation from design intent. Copyright General Motors Company Provided by IHS under license with General Motors CompanyNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-GM WORLDWIDE ENGINEERING STAN
45、DARDS GMW14871 Copyright 2012 General Motors Company All Rights Reserved November 2012 Page 5 of 16 6 Safety This standard may involve hazardous materials, operations, and equipment. This standard does not propose to address all the safety problems associated with its use. It is the responsibility o
46、f the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 7 Notes 7.1 Glossary. Maximum Allowable Torque: The value of torque beyond which the seal is no longer functional or the threaded fitting, port or
47、tube is deformed beyond functionality (e.g., maximum allowable reduction of port through-hole). See Figure 2. Seal Torque: The minimum value of torque that is needed for the threaded fitting to provide a sealed connection. See Figure 2. Seat Torque: The torque level at which the fitting contacts the
48、 seat. It is characterized by a change in the torque angle signature from an upward curve to a straight line. Ultimate Torque: The maximum torque the joint can tolerate prior to fracture or strip. See Figure 2. Figure 2: Maximum Allowable Torque Zero Angle Reference Torque: Torque value at which the
49、 angle of all samples is set to zero for analysis purposes. 7.2 Acronyms, Abbreviations, and Symbols. ABS Anti-lock Braking System ISO International Organization for Standardization PAD Product Assembly Document (also known as Master Process Document (MPD) RPM Revolutions per minute 8 Coding System This standard shall be referenced in other documents, drawings, etc., as follows: Test to GMW14871 9 Release and Revisions This standard was orig
