1、This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. APRIL 2009 Page 1 of 7 NAVISTAR, INC. Engineering Standard Parts NUMBER: ESP-EM-56
2、.101-GS TITLE: Prevailing Torque Hex Nuts All Metal General Specifications Metric Series (Noun Code 5780) CURRENT ISSUE DATE: APRIL 2009 WRITTEN/REVIEWED BY: Corporate Technical Standards APPROVED BY: Corporate Technical Standards SUPERSEDES ISSUE OF: May 2008 PRINTED COPIES OF THIS DOCUMENT MUST BE
3、 VERIFIED FOR CURRENT REVISION Change Notice: Added general specifications for M22 nut. GENERAL: This specification contains elements of the following standards: American National Standards Institute: B 18.16.3M International Organization for Standardization: ISO 2320, 7042, 7719 Prevailing torque t
4、ype is a nut which is frictionally resistant to rotation due to a self-contained prevailing torque feature, and not because of a compressive load developed against the bearing surface of the nut. Prevailing torque is the torque necessary to rotate the nut on its mating externally threaded component,
5、 with the torque being measured while the nut is in motion, and with no axial load in the mating component. Inch series prevailing torque hex nuts - all metal, may be found in ESP-E-56.101-GS. Letter symbols designating dimensional characteristics are in accord with those used in ANSI and ISO standa
6、rds. PREFERRED PARTS POLICY: Preferred parts are so designated to reduce variety of parts and assure maximum availability and cost savings: Nominal Sizes: M6, M8, M10, M12, M16, M20, M24, M30, and M36 Material: Class 10 Finish: Phosphate Coating (PHC) WIDTH ACROSS FLATS: The width across flats will
7、be distance, measured perpendicular to the axis of the nut, between two opposite wrenching flats. The maximum width across flats may be exceeded by 0.05 mm to allow for nut deformation caused by introduction of the prevailing-torque feature. The width across flats may be less than the specified mini
8、mum in the deformed portion of the nut containing the prevailing-torque feature. THICKNESS: The nut thickness will be the overall distance, measured parallel to the axis of the nut, from the top of the nut to the bearing surface of hex nuts. Raised identification markings, if present, will be exclud
9、ed. WRENCHING HEIGHT: The wrenching height is the distance, measured at a corner of the hex, from the bearing surface of hex nuts, to the last plane of full formed hex, i.e., the plane perpendicular to the nut axis which is closest to the top of the nut and at which the width across corners is withi
10、n its specified limits. Wrenching height for hex nuts is dimension M, in Table 1, and is subject to measurement. BEARING SURFACE: Hex nuts will have a chamfered bearing surface. The diameter of the bearing surface will not exceed the width across flats nor be less than the bearing face diameter spec
11、ified on Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General Specifications CURRENT ISSUE DATE: April 20
12、09 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. APRIL 2009 Page 2 of 7 the page. The bearing surface will be flat and perpendic
13、ular to the axis of the thread within the total runout limit specified on the last page. TRUE POSITION OF TAPPED HOLE: The axis of tapped hole will be located at true position with respect to the axis of nut body within a tolerance zone having a diameter equivalent to 3 percent of the maximum width
14、across flats, regardless of feature size. COUNTERSINK: The tapped hole will be countersunk on the bearing face, and may be countersunk on the top face. The countersink included reference angle will be 90 deg to 120 deg. The maximum countersink diameter will be 1.15 times the nominal thread diameter
15、(major diameter) for nuts M4 and smaller, the nominal thread diameter plus 0.75 mm for M5 through M8 nuts, and 1.08 times the nominal thread diameter for M10 and larger nuts. The minimum countersink diameter will be the nominal thread diameter. THREADS: Threads, prior to introduction of the prevaili
16、ng-torque feature, will be metric coarse threads with class 6H tolerances in accordance with ANSI B1.13M. Nuts M10 and smaller will assemble a minimum of one-half turn, and nuts M12 and larger will assemble a minimum of one full turn by hand on a basic GO thread plug gage. The plug gage will be with
17、out a chip groove, and will have a point with dimensions conforming to those for the point on metric hex head bolts given in ESP-BM-1.101-GS. MATERIAL: Steel, Class 10 per CEMS A-31, Part II. FINISHES: In accordance with the International Engineering Material Specification and class listed below: Pl
18、ain (PLN) Free from dirt and rust and coated with a light oil film. Phosphate Coated (PHC) CEMS G-1, Class B-2. Zinc Aluminum Clear (ZACLR) TMS-4518, Type II. All nuts will be provided with a supplementary lubricant following plating which will be clean and dry to the touch. Lubricant will not deter
19、iorate due to temperature and humidity variations so as to affect nut performance for a period of one year when nuts are stored, shipped, or handled in a normal manner. RESTRICTED CHEMICAL SUBSTANCES: Effective January 1, 2007, all product supplied to the requirements of this specification must comp
20、ly with the requirements of the CEMS B-50 specification. WORKMANSHIP: Nuts will not contain an excess of surface imperfections which might affect their serviceability, such as burrs, seams, laps, loose scale, and other irregularities. PERFORMANCE REQUIREMENTS: The prevailing torque developed by nuts
21、 during their first installation or any subsequent installation or removal, will not exceed the maximum first installation torque as specified in Table 1 when tested as specified in this standard. In addition, the prevailing torque developed by nuts during their first and fifth removals will not be
22、less than those specified in Table 1. Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General Specifications
23、 CURRENT ISSUE DATE: April 2009 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. APRIL 2009 Page 3 of 7 Table 1 - Proof Loads, Clam
24、p Loads and Prevailing Torques for Nuts Nominal Size Proof Load, kN Clamp Load, kN Prevailing Torque, Nm Class 9 Class 10 Class 10 First Installation Max First Removal Min Fifth Removal Min M6 18.1 20.9 12.5 4 0.55 0.4 M8 34.4 38.1 22.8 8 1.15 0.8 M10 54.5 60.3 36.1 14 2 1.4 M12 80.1 88.5 52.5 21 3.
25、1 2.1 M14 109 121 71.6 31 4.4 3 M16 149 165 97.5 42 6 4.2 M20 - 260 152 72 10.5 7 M22 - 321 189 90 13 9 M24 - 374 220 106 15 10.5 M30 - 595 350 140 19 14 M36 - 866 509 180 24 17 5 Note: The clamp loads for class 10 nuts are equal to 75 percent of the proof load of property class 10.9 bolts. Proof lo
26、ads are given in CEMS A-31, Part I. TEST METHODS: Proof Load Test: The test sample nut will be assembled on a test bolt or on a hardened mandrel with a minimum of three threads projecting through the nut. For referee test purposes, the hardened mandrel will be used. The maximum torque occurring duri
27、ng the assembly of the nut on the test bolt or mandrel will be recorded. A tensile load equal to the specified proof load for the nut, as given in Table 1, will be applied through the test bolt or mandrel against the nut bearing surface in an axial direction. The nut will resist this load without th
28、read stripping or rupture. The torque necessary to remove the nut from the test bolt or mandrel will not exceed the maximum torque occurring during assembly. Test Bolt: The bolt used for proof load testing nuts will have threads conforming to ISO 965, Part I, Class 6g tolerances. The test bolt will
29、have a proof load capability strength in excess of the specified proof load of the nut being tested. Hardened Mandrel: The mandrel used for proof load testing nuts will have threads conforming to ISO 965, Part I, Class 5h tolerances, except that the tolerance of the major diameter will be the lowest
30、 quarter of the 6g range on the minimum material side. The mandrel will be heat treated to a hardness of Rockwell C45 to C50. Hardness Test: Either Vickers or Rockwell hardness may be determined. Vickers testing will be in accordance with ISO R81, and Rockwell testing in accordance with ISO R80. For
31、 referee purposes, Vickers hardness will be determined. The hardness of the sample nut will be determined on the top or bottom face of the nut. The top or bottom surface of the nut will be prepared by grinding, removing sufficient material from the surface to eliminate the effects of plating, coatin
32、g or other surface condition. Material removal will also be such as to provide a flat area large enough to allow a hardness test to be made midway between the hex Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitt
33、ed without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General Specifications CURRENT ISSUE DATE: April 2009 This document is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Sup
34、pliers are required to assume all patent liability. 2009 by Navistar, Inc. APRIL 2009 Page 4 of 7 corner and the major diameter of the thread. The opposite surface (i.e., top or bottom of nut) will be prepared parallel to the test surface with removal of plating or coating. Prevailing Torque Test: T
35、wo test programs are included in this standard. The first, program A, is intended for the routine acceptance of lots of prevailing torque nuts as produced by the manufacturer and received by the user. It is generally considered that products meeting program B in qualification, may ordinarily be acce
36、pted by the routine test procedure of program A. Program A: Program A is recommended for routine inspection for lot acceptance. The prevailing torque test will be conducted at room temperature using a load measuring device. A test bolt will be inserted in the load measuring device, a test washer pla
37、ced on the bolt and the sample nut then assembled on the bolt. The nut will be advanced on the bolt until a minimum of two full bolt threads protrude through the nut. Nut tightening may be either manually with a torque wrench or with an equivalent torque-sensing power device. The maximum torque occu
38、rring while the nut is being advanced through the next 360 of nut rotation will be measured. For the nut to be acceptable, this torque will not exceed the first installation prevailing torque value as specified for the applicable nut in Table 1. Tightening will be continued until the nut is seated a
39、gainst the test washer. The length of the test bolt should be such that seating of the nut occurs when a length equivalent to four to seven thread pitches of the test bolt protrude through the top of the nut, measured from the end of the bolt. The nut will then be tightened until a tensile load equa
40、l to the clamp load, as specified in Table 1, is developed in the bolt. The test washer will be prevented from turning during nut tightening. The nut will then be backed off by the application of reverse torque until the tensile load in the bolt has been reduced to zero. The maximum torque occurring
41、 while the nut is being backed off through the next 360 of rotation will be measured. For the nut to be acceptable, this torque will not be less than the first removal prevailing torque value specified for the applicable nut in Table 1. Program B: Program B will be used when qualifying nuts, and als
42、o for referee inspection for lot acceptance. The Program A test procedure will be conducted. After the first removal prevailing torque has been measured, the nut will be backed off until the prevailing torque element is disengaged from the bolt thread. The nut will then be reassembled and removed fo
43、ur more times. On each assembly, the nut will be advanced sufficiently to allow a length equivalent to four to seven thread pitches to protrude through the nut. On each removal, the prevailing torque element will be disengaged from the bolt thread. This portion of the test need not be carried out in
44、 the load measuring device. During the fifth removal, the maximum torque occurring while the nut is being backed off through the first 360 of rotation will be measured. For the nut to be acceptable, this torque will not be less than the fifth removal prevailing torque value as specified in Table 1.
45、In addition, at no time during these four additional installations and removals will the torque exceed the maximum first installation prevailing torque value as specified in Table 1. Sufficient time will elapse between cycles of application of the torque to prevent overheating of the test assembly.
46、Copyright Navistar International Corporation Provided by IHS under license with INTERNNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-NUMBER: ESP-EM-56.101-GS TITLE: Prevailing Torque Hex Nuts All Metal - General Specifications CURRENT ISSUE DATE: April 2009 This d
47、ocument is restricted and may not be sent outside Navistar, Inc. or reproduced without permission from Corporate Technical Standards. Suppliers are required to assume all patent liability. 2009 by Navistar, Inc. APRIL 2009 Page 5 of 7 The speed of application and removal of the torque will not excee
48、d 30 rev/min, and will be continuous and uniform. Torque Measuring Device: The torque measuring device (torque wrench or power device) will be accurate within plus or minus 2 percent of the maximum of the specified torque range of the device. For referee purposes, all readings taken must fall within
49、 the upper 50 percent of the torque range of the measuring device. Load Measuring Device: The load measuring device used in the prevailing torque test will be an instrument capable of measuring the actual tension induced in the test bolt as the nut is tightened. The device will be accurate within plus or minus 5 percent of test clamp load being used. The bolt clearance hole in the backing plate will have
