求SAE标准( 二 ) _SAE

4.1 Test Conditions
The assemblies for each performance test shall be new and unused and shall be at least 24 h old. The last 4 h prior to testing shall be at a temperature of 15 to 32 °C (60 to 90 °F). Prior to installation of the hose assembly on a whip or cold bend test, all external appendages such as mounting brackets, spring guards, and metal collars shall be removed or long tubes shortened, or both. The temperature of the testing room shall be between 15 and 32 °C (60 and 90 °F) for all tests except brake fluid compatibility, cold bend, hot impulse, ozone, dynamic ozone, salt spray, and water absorption. SAE Referee Brake Fluid, RM 66-05, should be used for all tests requiring brake fluid. Different test results may be obtained using different fluids.
4.2 Test Procedures
4.2.1 100% PRESSURE TEST—The hose assembly shall be subject to a pressure test, using inert gas, air, water, or brake fluid as a pressure medium. Brake fluid shall meet SAE J1703/J1705. The test pressure shall be 10.3 MPa (1500 psi) minimum, 14.5 MPa (2100 psi) maximum for inert gas and air and 20.7 MPa (3000 psi) minimum, 24.8 MPa (3600 psi) maximum for water and nonpetroleum-base hydraulic brake fluid. Special care should be taken when gas or air is used. Under the pressure specified, gas or air is explosive if a failure should occur in the hose or hose assembly. The pressure shall be held for not less than 10 nor more than 25 s.
4.2.2 CONSTRICTION TEST—For qualification and lab testing, the constriction of the hose assemblies shall be measured with a gage plug as shown in Figure 1. Hold the assembly vertically at the fitting and insert the “A” diameter portion of the constriction gage into the end of the fitting. Allow the gage to drop of its own weight for the full length of the probe. The time required for the gage to drop shall not exceed 5s. Repeat this step for the other end of the brake hose assembly<.

The design of some fittings makes it impossible to insert the gage plug externally. For these assemblies, insert a special elongated gage plug into the opposite fitting and pass the probe through the hose, into and through the crimped area of the fitting being tested. If the gage plug becomes misaligned at the entrance to the second fitting, it may be necessary to align the hose to allow the plug gage to pass through. The special gage plug shall meet all the requirements of Figure 1, with the exception of the 76 mm (3 in) length, which must be increased appropriately so that its tip will extend past the hose opening. Some brake hose assemblies have fittings on both ends, brackets, and/or center fittings that cannot be entered with a gage plug. Cut these assemblies 50 mm ± 3 mm (2 in ± 0.1 in) from the end of the fitting and then test with the plug gage. (Reference Table 1, footnote 2).
4.2.3 VOLUMETRIC EXPANSION TEST—The expansion test is designed to measure, by fluid displacement, the volumetric expansion of the free length of assembled hydraulic brake hose when subjected to specified internal pressures. Water or SAE Referee Brake Fluid RM 66-05 should be used as a pressure medium.
【求SAE标准】4.2.3.1 If the specimen used in this test has been subjected to a pressure above 20 MPa (2900 psi) using any medium prior to this test, allow it to recover for 15 min.
4.2.3.2 Carefully thread the hose assembly into the adapters designed to seal in the same manner as in actual use. Do not twist. Maintain the hose in a vertical, straight position, without tension, while under pressure.
4.2.3.3 Bleed all the air from the system by allowing approximately 0.25 L (0.5 pt) of brake fluid or water to flow through the hose assembly and into the buret. Removal of air bubbles may be facilitated by moving the hose back and forth. Close the valve to the buret and apply 20.0 MPa +0, ?0.14 MPa (2900 psi +0, ?20 psi) to the hose assembly. Within 10 s, inspect the hose assembly for leaks at the connections and then release the pressure completely in the hose. Adjust the brake fluid or water level in the buret to zero. With the valve to the buret closed, apply 6.9 MPa +0, ?0.14 MPa (1000 psi +0, ?20 psi) to hose assembly and seal this pressure in the hose within 5 s ± 3 s. Within 3 s, open the valve to the buret for 10 s +3, ?0 s and allow the brake fluid or water level in the expanded hose to rise in the buret. The brake fluid or water level in the buret should be constant within that time period.

求SAE标准( 二 )

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