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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 entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising therefr
2、om, 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: (724) 772-8512 FAX: (724) 776-0243 TO PLACE A DOCU
3、MENT ORDER; (724) 776-4970 FAX: (724) 776-0790 SAE WEB ADDRESS http:/www.sae.org Copyright 1995 Society of Automotive Engineers, Inc. All rights reserved.Printed in U.S.A. SURFACE VEHICLE 400 Commonwealth Drive, Warrendale, PA 15096-0001 RECOMMENDED PRACTICE Submitted for recognition as an American
4、National Standard J1236 REV. MAY95 Issued1972-02 Revised1995-05 Superseding J1236 APR93 (R) CAST IRON SEALING RINGS (METRIC) ForewordThis Document has also changed to comply with the new SAE Technical Standards Board Format. 1.ScopeThe purpose of this SAE Recommended Practice is to establish specifi
5、cations for use as a guide to the automatic transmission and hydraulic systems designer, helping him to select cast iron sealing ring width, thickness, coatings, and other accepted design details. 2.References 2.1Applicable PublicationThe following publication forms a part of this specification to t
6、he extent specified herein. The latest issue of SAE publications shall apply. 2.1.1SAE PUBLICATIONAvailable from SAE, 400 Commonwealth Drive, Warrendale, PA 15096-0001. SAE J1590Internal Combustion EnginesPiston RingsMaterial Specifications 3.MaterialsCast iron sealing rings are generally made from
7、gray cast iron piston ring material. Gray cast iron piston ring material is used for general automotive application. Gray cast iron piston rings are made with a high carbon equivalent iron and with casting techniques that promote, in the small section castings, the most desirable graphite and matrix
8、 microstructural conditions for wear resistance and adequate mechanical and physical properties. The chemical element ranges shown in Table 1 represent typical chemical compositions for gray cast iron piston rings. Reference also SAE J1590 Class 10 Subclass 12. 3.1CompositionAlloying elements such a
9、s chromium, copper, molybdenum, vanadium, tin, etc., may be added to enhance the material properties or improve the material for special applications. TABLE 1CHEMICAL ELEMENT RANGES Elements% Total carbon3.503.95 Silicon2.203.10 Manganese0.400.80 Phosphorus0.300.80 Sulfur0.13 max SAE J1236 Revised M
10、AY95 -2- 3.2HardnessRockwell B 95107 or equivalent. 3.3MicrostructureGray cast iron piston rings are made to present an abrasion resistant matrix combined with the best graphite attainable in gray iron for mechanical and physical properties. The matrix is essentially completely pearlitic or sorbitic
11、 with a minimum of free ferrite and massive cementite. The phosphorus constituent, steadite, is uniformly distributed in nonmassive particles. The graphite will consist principally of randomly oriented flakes that are described as AFS-ASTM Type A or A- B combination. The graphite particles will norm
12、ally be of AFS-ASTM sizes 4 to 8. 4.Application Design Data 4.1Surface Finish and CoatingsSealing rings are usually phosphate or oxide coated. Occasionally, they are used uncoated or covered with a flash of tin or other metallic plating. Ring side finish to be 0.90 m (35.0 in) Ra before coating. OD
13、is to be smooth-turned (see Figure 1). FIGURE 1SEAL RING DESIGN 4.2Axial Width (W)The widths shown in Table 2 are considered “common“ sizes. Other widths may be necessary for special applications. The minimum sealing ring width tolerance has historically been 0.025 mm (0.0010 in) for uncoated and ph
14、osphated rings less than 127 mm (5.0000 in) in diameter and 0.038 mm SAE J1236 Revised MAY95 -3- (0.0015 in) for rings more than 127 mm (5.0000 in) in diameter. Consult a ring manufacturer for tolerancing of plated rings. The general failure mode of a hook joint sealing ring is that it spins in the
15、bore and wears on the OD. When the hooks engage, due to the OD wear, they limit the travel and the ring fails to seal on the OD. This typically results in not enough pressure at the clutch. Based on side versus OD torque on the sealing ring, the nominal width should be approximately 1.4 times the ra
16、dial thickness. Consult a ring manufacturer if the width is less than 1.2 times the radial thickness. (See Figure 1 and Figure 2). 4.3Radial Wall Thickness (T)It is recommended that sealing ring radial wall thicknesses be 0.030 to 0.040 times gage diameter. If a somewhat thinner section is desired t
17、o minimize groove depths and shaft diameters, a ring manufacturer should be consulted so that a radial wall thickness can be recommended that will still give good sealing characteristics along with the reduced thickness. (See Figure 1.) 4.4End Clearance or Compressed Gap (G)This document applies to
18、butt joint and hook joint rings. The tolerance required for manufacture increases as the ring diameters get larger. The smallest recommended clearance is 0.05 mm (0.002 in), which should be measured at the OD of the ring in a gage of minimum bore diameter as illustrated in Figure 1 and Figure 2. Con
19、sult a ring manufacturer for the upper limit since this dimension considerably affects cost and performance. It would be in the interest of both parties to make sure the tolerance is specified to the best “value added“ for a tight tolerance. 4.5Hook Joint DetailsHook joint rings are used when assist
20、ance is needed in blind assembly operations. The direction of the hooks is optional as shown in Figure 2. Also shown are the other necessary hook dimensions. TABLE 2SEALING RING WIDTH Nominal Width Maximum Sealing Ring Width 2.000 mm1.990 mm (0.0783 in) 2.385 mm (3/32 in)2.375 mm (0.0935 in) 3.000 m
21、m2.990 mm (0.1177 in) 3.160 mm (1/8 in)3.150 mm (0.1240 in) 3.972 mm (5/32 in)3.962 mm (0.1560 in) 4.000 mm3.990 mm (0.1571 in) 4.747 mm (3/16 in)4.737 mm (0.1865 in) 5.000 mm4.990 mm (0.1965 in) 6.000 mm5.990 mm (0.2358 in) 6.335 mm (1/4 in)6.325 mm (0.2490 in) SAE J1236 Revised MAY95 -4- FIGURE 2H
22、OOK JOINT DETAILS 4.6Grooving RecommendationsThe ring groove must be deep enough so that the ring will not bottom in the groove at extreme conditions. The groove root diameter (GRD) may be calculated by using the formula shown in Figure 3. Note that adding ID chamfers to the ring would allow the rin
23、g to nest into the groove radius and make GRD max larger and help reduce hang-down (H in 5.1). Also note that reducing ring radial thickness tolerance and GRD tolerance would also help reduce hang-down. The groove sides should be cut perpendicular to the axis of the shaft within 0.02/20 maximum. The
24、 groove sides should be flat within 0.025 mm (0.001 in) maximum in 360 degrees and 0.0065 mm (0.00025 in) maximum in 90 degrees. The surface finish on the groove walls should be 1.3 m (50.0 in) Ra. SAE J1236 Revised MAY95 -5- FIGURE 3GROOVE DIAMETER AND SIDE CLEARANCE 5.Sample Calculation 5.1Loading
25、 Chamfer Diameter CalculationIn order to properly install the carrier and ring assembly in the bore, without a ring compressor, a chamfer of sufficient diameter is required to allow for the ring bottoming in the groove on one side and the ring hanging out on the other side as illustrated in Figure 4
26、. The minimum radial dimension of the chamfer is equal to the maximum hang-down and can be calculated using Equation 1: (Eq. 1) The minimum diameter of the chamfer can be calculated using Equation 2: SAE J1236 Revised MAY95 -6- (Eq. 2) FIGURE 4LOADING CHAMFER DETAILS 5.2Example Calculation for Seali
27、ng Ring ApplicationSee Figure 1 through Figure 4. Given: B = 50.5250.54 C = 50.2950.42 E = 0.065 max F = 0.25 max T = 2.032.29 Z = 53.98 max SAE J1236 Revised MAY95 -7- Check: BMIN - CMAX 0.10 50.52 - 50.42 = 0.10 GRDMAX = CMIN - 2(TMAX + EMAX + FMAX) = 50.29 - 2(2.29 + 0.065 + 0.25) = 50.29 - 5.21
28、GRDMAX = 45.08 GRDMIN = GRDMAX - 0.25 = 45.08 - 0.25 GRDMIN = 44.83 HMAX = 53.98 - 49.525 HMAX = 4.46 XMIN = BMAX + 2HMAX = 50.54 + 8.92 XMIN = 59.46 6.Notes 6.1Marginal IndiciaThe change bar (l) located in the left margin is for the convenience of the user in locating areas where technical revision
29、s have been made to the previous issue of the report. An (R) symbol to the left of the document title indicates a complete revision of the report. PREPARED BY THE SAE TRANSMISSION/AXLE/DRIVETRAIN FORUM SAE J1236 Revised MAY95 RationaleNot applicable. Relationship of SAE Standard to ISO StandardNot a
30、pplicable. ApplicationThe purpose of this SAE Recommended Practice is to establish specifications for use as a guide to the automatic transmission and hydraulic systems designer, helping him to select cast iron sealing ring width, thickness, coatings, and other accepted design details. Reference Section SAE J1590Internal Combustion EnginesPiston RingsMaterial Specifications Developed by the SAE Transmission/Axle/Drivetrain Forum