SAE J1405-1990 OPTIONAL IMPULSE TEST PROCEDURES FO

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between the number of cycles of flexing and impulse and assures that the test specimen is in a different configuration of each succeeding impulse.

FIGURE 1—FLEX IMPULSE T EST HOSE GEOMETRY

The vertical centerline of a stationary manifold is positioned a distance "A" from the center of revolution of the revolving manifold. This distance was determined empirically such that the test specimen is subjected to back bending motion near each fitting with the radius of bend at that point being greater than the applicable SAE minimum bend radius. However, when the revolving manifold reaches the position nearest the stationary manifold, the bend 1 radius inside the loop is smaller than the applicable SAE minimum bend radius. Distance "A" is calculated with the following equation:

(Eq. 2)

Specimens for flex-impulse testing should be mounted with straight end fittings on the rig as described above using care to avoid imparting twist to the hose. (Angular fittings may be used, provided they are installed in such a position to assure the hose travel and geometry of Figure 1.) A like number of samples, preferably not less than three, should be tested simultaneously and should be run to failure.

T o accelerate completion of the test for comparative purposes, a pressure based on actual burst values of the hose is recommended, with flexing and nonflexing specimens to be tested at the same pressure. Suggested procedure is to first determine the average burst strength for the test length of hose and from this calculate the impulse test pressure as 35% of average burst. If this test procedure does not produce failures within the desired range, a higher or lower percentage may be used.

1.75 (minimum bend radius + hose O.D.)

4.

Option II - Flex Impulse Test 4.1Purpose—T o establish requirements for impulse testing with the addition of flexing. This is a specialized test

which is not a requirement of SAE J517, nor is it specified in SAE J343. It is intended to provide a standard method to flex-impulse hose assemblies when flexing is deemed necessary.

4.2

Test Procedure—Four unaged hose assemblies for flexing are to be made up with free hose length in accordance with the following equation:

(Eq. 3)Performance of the flex-impulse test requires a supplementary rig capable of moving one test manifold in a continuous circular pattern as shown in Figure 1. This manifold is geared so that the center lines of the hose fittings at hose attachment stay parallel at all times. A variable drive is provided, and the number of revolutions per minute are to be controlled to 36% ± 2 of the impulse cycles per minute. This maintains a proportionality between the number of cycles of flexing and impulse and assures that the test specimen is in a different configuration on each succeeding impulse.

The vertical centerline of a stationary manifold is positioned a distance "A" from the center of revolution of the revolving manifold. This distance was determined empirically such that the test specimen is subjected to back bending motion near each fitting with the radius of bend at that point being greater than the applicable SAE minimum bend radius. However, when the revolving manifold reaches the position nearest the stationary manifold, the bend radius inside the loop is smaller than the applicable SAE minimum bend radius. 2 Distance "A" is calculated with the following equation:

(Eq. 4)

Specimens for flex-impulse testing should be mounted with straight end fittings on the rig as described above using care to avoid imparting twist to the hose. (Angular fittings may be used provided they are installed in such a position to assure the hose travel and geometry of Figure 1.)

4.3Test Requirements—The hose assemblies shall be tested at the impulse pressures, temperatures and

minimum bend radii, for the minimum number of impulse cycles, as specified in SAE J517 for 100R series hoses. Other test parameters, as agreed upon by the supplier and/or user may be used.

5.Option III - Cool Down Leakage Test

5.1Purpose—T o establish requirements for performing a cold start leakage test to be used in conjunction with both flexing or nonflexing impulse tests.

5.2

Test Procedure—The impulse test unit shall be shut down at 40% ± 10 and 90% ± 10 of the required number of impulse cycles and allowed to cool until the test oil and hose assemblies reach a temperature of 30 °C ± 3(85 °F ± 5). Accelerated cool down procedures, i.e. fans, heat exchangers, etc., may be used to speed the cooling process. Check test assemblies to assure they are clean and dry. With oil heater turned off, resume the test and observe and note leakage for 1000 impulse cycles. The acceptable rate of leakage shall be as agreed upon by the supplier and/or user. (See SAE J1176 for leakage classes.)

After completing the 1000 impulse cycles, turn on oil heater and continue the impulse test.

If leakage is noted during the cool down cycle, notation shall also be made as to whether or not a seal-off was effected as the temperature came back up. Results are applicable only to the specific hose construction and size, hose fitting design and size, and fitting assembly technique.

Free hose length = 4.142 (minimum bend radius) + 3.57 (hose O.D.)1.75 (minimum bend radius) + hose O.D.

6.1Marginal Indicia—The change bar (l) located in the left margin is for the convenience of the user in locating

areas where technical revisions 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 FLUID CONDUCTORS AND CONNECTORS TECHNICAL COMMITTEE S2—

HYDRAULIC HOSE AND FITTINS SUBCOMMITTEERationale—In 1987 FCCTC was approached by ORMTC and asked to comment on a proposed new Hose T est Procedure, XJ1438, which they had been working on since 1984.

This document contained a flex impulse test and a "cool down" or "cold start" leakage test which were not then part of any SAE standard.

FCCTC-SC2, which was given XJ1438 to review, suggested this document be combined with J1405 which was already in existence. The document you are being asked to vote on is a combination of XJ1438 and J1405.

The new J1405 contains 3 test options.

Option I: Comparative Flex Impulse T est Procedure

This is a procedure designed to generate test data, with and without flexing, to compare these two options and the effect they have on hose life. Option I is a duplicate of J1405 as it formerly EXISTED.

Option II: Flex Impulse Test

This is new material which describes the procedure to be used to conduct a flex impulse test.

Option III: Cool Down Leakage Test

Also new, we have included the test procedure to use for checking "cold start" leakage, with or without flexing.

NOTE—This document has already been successfully balloted to ORMTC-SC4 and FCCTC-SC2 and FCCTC.

Relationship of SAE Standard to ISO Standard—Not applicable.

Application—The procedures contained in this SAE Recommended Practice have been developed to establish uniform methods for impulse testing of hydraulic hose assemblies under special conditions not specified in SAE J343 for SAE J517 hoses. Basic impulse test parameters are to be in accordance with SAE J343 except as modified in this document.

Reference Section

SAE J343—T ests and Procedures for SAE 100R Series Hydraulic Hose and Hose Assemblies

SAE J517—Hydraulic Hose

SAE J1176—External Leakage Classifications for Hydraulic Systems

Developed by the SAE Fluid Conductors and Connectors Technical Committee S2—Hydraulic Hose and Hose Fittings Subcommittee

Sponsored by the SAE Fluid Conductors and Connectors Technical Committee