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The definitions and illustrations in this SAE Recommended Practice are intended to establish common nomenclature and terminology for automotive transmission one-way clutches.

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use.The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems.The specific purpose of this document is to define a µPVT Test for the evaluation of the variation of wet friction system performance as a function of speed, temperature, and pressure. This procedure is intended as a standard for both suppliers and end users.The only variables selected by the supplier or user of the friction system are:a. Friction materialb. Fluidc. Reaction platesThese three variables must be clearly identified when reporting the results of this test.

The following is a list of the most common terminology used in describing automatic transmission functions.

The range of test conditions on the dynamometer shall be sufficient to determine the primary operating characteristics corresponding to the full range of vehicle operations. The characteristics to be determined are: a Torque ratio versus speed ratio and output speed b Input speed versus speed ratio and output speed c Efficiency versus speed ratio and output speed d Capacity factor versus speed ratio and output speed e Input torque versus input speed NOTE: For more information about these characteristics and the design of hydrodynamic drives, refer to “Design Practices: Passenger Car Automatic Transmissions,” SAE Advances in Engineering, AE-18 (Third Ed.) or AE-29 (Fourth Ed.).

The following listed definitions are intended to establish terminology and criteria for describing the various kinds of automotive transmissions. A specific arrangement may be described by a combination of several of these definitions.

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. This SAE No. 2 friction test monitors the µ-v curve for a negative slope which can be used to evaluate a wet clutch system (WCS) anti-shudder performance and can be used for any wet driveline mechanism. WCS shudder is considered a clutch failure condition. The cause of shudder is consistent with glazing as the primary failure mode. It has been shown that a substantial loss of the wet friction material surface porosity leads to a glaze forming on the friction material surface. This process typically leading to a negative dµ/dv slope over time as addressed in SAE 2020-01-0560.

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The specific purpose of this SAE Recommended Practice is to define a procedure to determine intrinsic properties of friction materials such as compressive modulus and rebound/recovery time at specific fatigue test pressures. Results from this test will both independently characterize the friction material and serve as input to the compression fatigue test. NOTE: If this test is intended to determine the rebound interval for the compression fatigue test, then the maximum test pressure (Pmax) in this procedure must be selected with future fatigue testing levels in mind. It is important that the rebound time is sufficient at the maximum apply pressure to allow the matieral to rebound back to its original thickness. Standard reporting processes are recommended.

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. a. The specific purpose of this document is to define a compression fatigue life testing procedure for wet friction material. This procedure is intended as a standard for both the suppliers and end users. The only variables selected by the supplier or user of the friction system are: a. Friction Material b. Fluid c. Maximum Load d. Fatigue Test Cycle requirements These variables must be clearly identified when reporting the results of this test. If any of the test parameters or system hardware as described in this document are changed, other than the variables above, the data may not be reported as having been obtained using this procedure.

This test procedure is intended to apply to hydraulic pump suction filters and strainers used in automotive automatic transmissions that include hydraulic power pumps. The various paragraphs of Section 5 include a variety of tests and alternative tests that are not applicable to all filters and applications, so the engineer must specify which tests are to be performed for a particular application. These test procedures are intended to evaluate filter functional performance characteristics only, durability is not evaluated under this standard. Filter design requirements must be specified by the engineer on the filter assembly drawing, an applicable engineering specification, or summarized on an application data sheet similar to that found in this recommended practice. See Figure 6. Pressure circuit filters, both barrier and system contamination control types, are not covered under this standard.

This SAE Recommended Practice provides a method to determine the performance characteristics of the hydraulic oil pumps used in automatic transmissions and automatic transaxles. This document outlines the specific tests that describe the performance characteristics of these pumps over a range of operating conditions and the means to present the test data. This document is not intended to assess pump durability.

This SAE Standard specifies the major dimensions and tolerances for Engine Flywheel Housings and the Mating Transmission Housing Flanges. It also locates the crankshaft flange face or the transmission pilot bore (or pilot bearing bore) stop face in relation to housing SAE flange face. This document is not intended to cover the design of the flywheel housing face mating with the engine crankcase rear face or the design of housing walls and ribs. Housing strength analysis and the selection of housing materials are also excluded. This document applies to any internal combustion engine which can utilize SAE No. 6 through SAE No. 00 size flywheel housing for mounting a transmission.

Since the torque converter and fluid coupling are commonly used components of automatic transmissions in industry, the SAE appointed a committee to standardize terminology, test procedure, data recording, design symbols, and so forth, in this field. The following committee recommendations will facilitate a clear understanding for engineering discussions, comparisons, and the preparation of technical papers. The recommended usages represent the predominant practice or the acceptable practice. Where agreement is not complete, alternates have been included for clarification. EXAMPLE: Two systems of blade angle designations are described. Consequently, when a blade angle is specified, the system should be designated. This SAE Recommended Practice deals only with the physical parts and dimensions and does not attempt to standardize the design considerations, such as the actual fluid flow angle resulting from the physical blade shape.

The following schematic diagrams reflect various methods of illustrating automotive transmission arrangements. These have been developed to facilitate a clear understanding of the functional interrelations of the gearing, clutches, hydrodynamic drive unit, and other transmission components. Two variations of transmission diagrams are used: in neutral (clutches not applied), and in gear. For illustrative purposes, some typical transmissions are shown.

The purpose of this SAE Recommended Practice is to establish guidelines for the automatic transmission and hydraulic systems engineer to design rectangular cross section seals for rotating and static grooved shaft applications. Also included are property comparisons of polymeric materials suitable for these applications. Historically, material covered in this document is not intended to include aluminum contact applications.

The definitions and illustrations in this SAE Recommended Practice are intended to establish common nomenclature and terminology for automotive transmission one-way clutches.

This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a 6000 rpm stepped power test for the evaluation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 6000 rpm and is intended as a standard procedure for common use by both suppliers and end users.

This SAE Recommended Practice is intended as the definition of a standard test, which may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a μPVT Test for the evaluation of the variation of wet friction system performance as a function of speed, temperature, and pressure. This procedure is intended as a standard for both suppliers and end users. The only variables selected by the supplier or user of the friction system are: a Friction material b Fluid c Reaction plates These three variables must be clearly identified when reporting the results of this test.

This SAE Recommended Practice is intended as the definition of a standard test, but may be subject to frequent change to keep pace with experience and technical advances. This should be kept in mind when considering its use. The SAE No. 2 Friction Test Machine is used to evaluate the friction characteristics of automatic transmission plate clutches with automotive transmission fluids. It can also be used to conduct durability tests on wet friction systems. The specific purpose of this document is to define a 3600 rpm Stepped Power Test for the evaluation of wet friction system performance variation as a function of power level. This procedure uses an initial engagement speed of 3600 rpm and is intended as a standard procedure for common use by both suppliers and end users.

The range of test conditions on the dynamometer shall be sufficient to determine the primary operating characteristics corresponding to the full range of vehicle operations. The characteristics to be determined are: a Torque ratio versus speed ratio and output speed b Input speed versus speed ratio and output speed c Efficiency versus speed ratio and output speed d Capacity factor versus speed ratio and output speed e Input torque versus input speed NOTE: For more information about these characteristics and the design of hydrodynamic drives, refer to “Design Practices: Passenger Car Automatic Transmissions,” SAE Advances in Engineering, AE-18 (Third Ed.) or AE-29 (Fourth Ed.).

Figures 1 through 5 illustrate in simplified form some of the more common planetary gear arrangements in order to establish applicable terminology. Figures 6 and 7 provide additional examples that use elements of those gear arrangements. Gear ratio is the numerical ratio of input to output speed.