1、SAE Fluid Sealing Handbook Radial Lip Seals 1996 Edition SAE HS-1417 The Engineering Society mAEFor Advancing Mobility -Land Sea Air and Space INTERNATIONAL Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IH
2、S-,-SAE Fluid Sealing Handbook Radial Lip Seals 1996 Edition SAE HS-1417 Published by: Society of Automotive Engineers, Inc. 400 Commonwealth Drive Warrendale, PA 15096-0001 U.S.A. Phone: (412) 776-4841 Fax: (412) 776-5760 Copyright SAE International Provided by IHS under license with SAENot for Res
3、aleNo reproduction or networking permitted without license from IHS-,-All technical reports, including standards approved and practices recommended, are advisory only. Their use by anyone engaged in industry or trade or their use by governmental agencies is entirely voluntary. There is no agreement
4、to adhere to any SAE Standard or Recommended Practice, and no commitment to conform to or be guided by any technical report. In formulating and approving technical reports, the Technical Board, its councils, and committees will not investigate or consider patents which may apply to the subject matte
5、r. Prospective users of the report are responsible for protecting themselves against liability for infringement of patents, trademarks, and copyrights. Copyright O 1996 Society of Automotive Engineers, Inc. All rights reserved. Printed in the United States of America. ISBN 1-56091-719-9 Permission t
6、o photocopy for internal or personal use, or the internal or personal use of specific clients, is granted by SAE for libraries and other users registered with the Copyright Clearance Center (CCC), provided that the base fee of $50 per page is paid directly to CCC, 222 Rosewood Dr., Danvers, MA 01923
7、. Special requests should be addressed to the SAE Publications Group. 1-56091 -71 9-9/96 $.50. Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-Radial LOD Seal Standards Committee David D. Black CR Indu
8、stries John W. Abar Hydraulic Accessories Dr. Leslie A. Horve CR Industries Dennis J. Abraham Bayer Corporation Douglas B. Boyers CR Industries John J. Carr Freudenberg NOK Gen. Partnership Harold L. Chambers Ford Motor Co. Frank J. Charhut Chicago Allis Manufacturing Corp. Thomas P. Ciepichal Monro
9、e Auto Equip Co. Phillip W. Downey II General Motors Corp. Ramakrish Emmadi Chrysler Corp. Edward S. Esshaki George Fedorovich J.M. Clipper Raymond V. Gallagher Eagles Pitcher Automotive Group Michael R. Gerulski Federal Mogul Corp. Frederick Hatch Federal Mogul Corp. Mark W. Houy Chrysler Corp. Ron
10、ald A. Jackowski CR Industries Dr. David E. Johnston Freudenberg NOK Merrill L. Karcher Albert Troste1 Packings Ltd. T.P. Koch Ford Motor Co. Judith Kocsis Federal Mogul Corp. Ronny K. MacLaren CR Industries Leo R. Marcy Federal Mogul Corp. Eugene S. Mazurek Acadia Corp. Mark R. Moldovan Timken Co.
11、Bruce L. Murden Rockwell International James Oshanski Acadia Polymers Dennis L. Otto Timken Co. Mark G. Pahios Indianhead Ind. Ralph D. Proctor Bob Puri GMC David Sakata Freudenberg NOK Gen. Partnership John A. Serio Navistar International Trans. Corp. Kenneth J. Seyuin Stanley N. Smith Federal Mogu
12、l Corp. Alvin L. Spicer General Motors Corp. William M. Stewart Joseph Anthony Stojkov Federal Mogul Corp. Robert N. Tanis Henkel Corp. Dale A. Van Deven ARS Manufacturing Inc. Lawrence Wagle Eaton Corp. Patrick M. Wilcox General Motors Corp. James R. Wood Milton F. Oliveira Delta Rubber Company Joh
13、n M. Taylor Ethyl Research Center Ralph T. Northnip, Jr. SAE Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-Seal Forum Committee Stanley N. Smith Federal Mogul Corp. Joseph Anthony Stojkov Federal Mog
14、ul Corp. Dennis L. Otto Timken Co. John W. Abar Hydraulic Accessories Dennis J. Abraham Bayer Corp. Darren B. Antoine Fel-Pro Inc. David D. Black CR Industries Joseph A. Bliss JBC Seals Packing how- ever, a closer examination at several diameters magnifica- tion could reveal imperfections which coul
15、d be the direct cause of seal leakage in some applications. Machine lead can screw oil out of the sump or contaminants into the sump when the shaft rotates. The specification for machine lead is zero k0.05. Details and recommended machining practices 1 Copyright SAE International Provided by IHS und
16、er license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-EFFECTS CAUSING LEAKAGE APPLICATION VARIABLES 1. Thermal Expansion FLUID SHAFT 2. Cracking of the Element 3. Deterioration less than 0.001 in (0.025 mm) and the measurement segment deflection limited
17、to 0.001 in (0.025 mm) at maximum loads to achieve repeatability. As the shaft measuring segment size decreases, the allowable deflection decreases proportionately. Smaller segments require deflec- 13 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or
18、networking permitted without license from IHS-,-tions that are difficult to control, even in the lab. A 0.20 in (5.0 mrn) segment measuring a 2 in (5 1 .O mm) oil seal should have a positional and deflection accuracy of 100 min (2.5 mm, Ra) to achieve less than 10% error. Errors of such a large magn
19、itude make small segment devices difficult to employ accurately on a consistent basis. Lip Openinu Pressum Perhaps the most commonly used indicator of radial load is the General Motors Lip Opening Pressure Device. It is most often used as a quality control instrument in produc- tion. Lip opening pre
20、ssure (LOP) is directly proportional to radial load and inversely proportional to shaft diameter and seal lip length. Lip opening pressure is related to a standard air flow oc- curring between the lip and a test mandrel when air pressure is applied to the air side of the seal. The procedure in SAE 5
21、946 describes a method for gaging lip opening pressure of a radial lip type seal. rea LIP Diameter Free lip diameter is important to the proper functioning of the seal. There are several test instrument methods for determining the diameter of a seal lip. Perhaps the simplest method is to use machine
22、d metal cones graduated in 0.005 in (0.13 or 0.2 mm) increments and placed on the reflecting surface of a light box. The procedure is to place the seals over the cone and record the point at which the sealing lip is light tight. This method provides measurement data within the range of accuracy cons
23、idered suitable for seal perfor- mance testing or quality control. A second method which is somewhat more accurate, but more time-consuming, is the use of a comparator. The diam- eter of each seal lip must be measured in at least six angular positions and then averaged to arrive at a true lip diamet
24、er. A third method, that of air gaging, has been developed as a means of providing a system whereby a Sealectorm ma- chine can be used to determine whether the free lip diameter is within an acceptable size range. However, the same sys- tem can be used to determine actual seal size if a series of sh
25、afts are provided in graduated sizes of 0.005 in (0.13 mm) increments. The method for gaging Free Lip Diameter is described in the Appendix (GM 9001P). Diameter tolerance is related to rate of air flow between the lip and mandrel of known size when air is applied at a standard pressure to the air si
26、de of the seal. Garter Springs The coiled tension spring, or “garter spring, is used to supplement the radial lip force. It is designed to close toler- ances in order to maintain an adequate radial lip force. See SAE 5946 in the Appendix for techniques on measuring the spring variables. Radlal Wall
27、Uaratlon Lip-to-Case Eccenuicl Seal lip eccentricity is the displacement of the seal lip diameter center in relation to the seal case OD and is related to the method of manufacture. Seals of the bonded and molded lip design are normally within limits as shown in 5946 (Appendix). This mechanical vari
28、able can be deter- mined in test seals by means of a toolroom shadowgraph. Seals are placed in a V” block or on two rollers and rotated to determine the variation of the radial wall. The value of the total deviation measured by this method is twice the ac- tual eccentricity value to be assigned to t
29、he seal being mea- sured. Environmental Testlng When the mechanical properties of the candidate lip seals have been established, it is sometimes desirable to conduct dynamic tests on the seals under controlled environmental testing conditions. The time spent in conducting laboratory seal tests is in
30、valuable in determining their performance in the actual application. Refer to SAE 5110 in the Appendix. Exclusion tests are described in RMA OS- 18. 14 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-O
31、btaining Service Performance - 140 - 130 - 120 - 110 - 100 - 90 - 00 - 70 - 60 Field Failura Analysis Reporting a Field Failure When a sealing application fails to perform as expected in service, it usually is assumed that the seals have failed. However, in many instances, the seal itself might not
32、be the cause of failure. Failure can occur for a variety of reasons associated with other sealing system components. The initial step in determining the cause of poor perfor- mance is to review the operating conditions and requirements. This is the identical step that is taken in selection or design
33、 of a seal for an application. However, when a sealing system fails to perform, the operating conditions and requirements should be reviewed to determine if any factor was overlooked or omitted in initial seal selection or design. It is suggested that the Sealing System Leakage Analysis Checklist sh
34、own in the Appendix (RMA OS-17, Sealing System Leakage Analysis Guide) be used to evaluate field failures. Application Conditions Speed - The type of motion that the seal will be sub- jected to must be determined. The seal may be used on shafts or in housings that rotate, reciprocate, or oscillate.
35、It is nec- essary that the motion of both the housing and shaft be known. Usually, only one type of motion is encountered in an appli- cation. However, intermittent reciprocation in rotating and oscillating applications due to bearing end play is frequently encountered. In these instances, the amoun
36、t of end play un- der load and the frequency of occurrence should be known. The maximum speed must be known. The rotational speed in rpms can be converted to rubbing speed in feet per minute (meters per second) so that comparisons of rotational speed and rubbing speed can be made with operating spee
37、ds of simi- lar successful applications. The maximum operating speed can vary greatly between different seal designs. Experience with other applications using the same basic seal design and compound in a similar application is valuable in determining the suitability of the seal for the required oper
38、ating speed. However, the maximum operating speed for any specific seal design will be dependent on specific application parameters, such as the lubricant used, the operating temperature and pressure, and the performance level expected. The maximum operating speed is not all the information required
39、 regarding the speed of the application. It is neces- sary to know the complete cycle of operating speeds, includ- ing the frequency of starts and stops, and the percentage of the time that the application is actually operating. Starts and stops, long downtime periods, and low speed operation can al
40、l be detrimental to seal performance under specific appli- cation conditions. At very low speeds it is difficult to main- tain adequate lubrication. Long periods of downtime can cause lubricant starvation in the seal lip area when the appli- cation is restarted. As speed increases, the heat generate
41、d increases and the seal operating temperature increases. The maximum speed is critical since most sealing materials have definite upper temperature limits. TemDerature - The maximum and minimum operating and ambient temperatures must be known to determine if the compound selected is suited for the
42、application. The maxi- mum and minimum temperature capabilities for various fami- lies of compounds are contained in Chapter III of this manual. The temperatures provided are the maximum and minimum sustained temperatures that the specific compound family can withstand. Individual compounds within e
43、ach family can operate beyond the stated temperature limits. However, this is usually at the sacrifice of some other property of the com- pound. The seal underlip temperature can be significantly higher than the bulk oil temperature due to friction. If the seal operating temperature cannot be measur
44、ed, it must be estimated from knowledge of the bulk fluid temperature, in- ternal pressure, speed, and cooling conditions. A typical underlip temperature rise in OF would be approximately K s, where s = shaft speed in Wmin (ds) and K varies from 1 - 2 for Fahrenheit and 5 - 10 for Celsius calculatio
45、ns (see Figs. 11, 12, and 13). NOTE: The previous discussion of polymer temperature limits was concerned with bulk oil temperatures, not underlip temperatures. The minimum temperatures are established for each seal family to indicate the lowest temperature that the seal can be subjected to in “norma
46、l“ operation without breaking or tear- ing the lip material. Obviously, the lower limit is dependent on the dynamic runout of the shaft. One factor that is not considered in establishing the minimum temperature is the seal wear rate. The low temperature wear rate of a lip LIP INTERFACE TEMPERATURE (
47、Nitrile Rubber) Standard 011 10W.30 1.75 inch through 4.75 inch (44mm - 120mm) shalt diameter W a I- W 40 5 w I- Y Y 2 0 m “E 300 200 260 240 220 200 100 160 140 0123456 SHAFT SPEED (F.P.M. x 1OOO) (MISec x 5) Figure 1 1-Lip Interface Temperature 15 Copyright SAE International Provided by IHS under
48、license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-“C “F UNDERLIP TEMPERATURE DIFFERENCE vs SHAFT SPEED Conventlonal Trimmed Llp Seal 3.000 Inch (76.2mm) Shaft Dlameter 250F (121 OC) Sump SAE 10W30 Oll AIR 120 - POLYACRYLATE w O 1000 2000 3000 4000 5000
49、SHAFT SPEED (RPM) Figure 12-Underlip Temperature Differential for Different Seal Lip Materials ISOTHERMAL SHAFT TEMPERATURES 200F (93C) SUMP Figure 13-Interface Radial Lip Seal Temperatures 16 Copyright SAE International Provided by IHS under license with SAENot for ResaleNo reproduction or networking permitted without license from IHS-,-Figure 13-Interface Radial Lip Seal Temperatures material does not necessarily cor
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