GB 7128-2008Automotive air brake hose and hose assemblies (English PDF)

4.1 Permanent joint

Permanent joint when the hose fitting, the hose assembly of the hose to comply with Table 1, A, and size requirements AI AII type hose.

4.2 Wild-type connector assembly

When the hose assembly wild-type connector assembly, the hose of hose assemblies shall comply AI table and a variety of hose AII shall comply with size requirements or Table 1 A hose 10, 12 and 13SP size requirements specifications. Wild-type connector assembly and with AI AII Different type of hose used.

6.1 Performance Acceptance

6.1.1 Pipe fittings

Fittings shall comply with all parts of this standard. After fitting to the hose, the smallest diameter of the tube or hose is not less than the joint Table 1 66% of the minimum inner diameter of the hose shown in FIG. All hose assemblies before any other test of this standard should be performed by this requirement.

6.1.2 Verify pressure

In the hose assembly charged air or nitrogen pressure of 2MPa ± 0.1MPa, and immersed in water should leak 30s.

6.1.3 The minimum burst pressure Minimum burst pressure test according to GB/T 5563 for, when the hose or hose assembly is subjected to pressure 6MPa, there should be no blasting, vent the drain pipe joint or separation.

6.1.4 Assembly Tensile strength

Take a 450mm long hose assemblies (including joint) were tested for the rate of longitudinal stretching 25mm/min ± 2.5mm/min, and Test until separation of the joint hose or hose damage. The nominal size of 6mm and less occurrence of failure load specifications of not less than 1100N, Nominal size of 6mm or more is not less than 1450N.

6.1.5 Change in length

Length variation test shall GB/T 5563 (elongation and contraction) of the initial pressure measurements are made at 0.1MPa. Hose or hose Change in length of the assembly should be measured at 1.5MPa, and the variation range is between + 5% to 7%.

6.1.6 Adhesive properties

Adhesion tests carried out on a sample shall only initial unaged.

6.1.6.1 Adhesion performance fiber reinforced hose

Adhesion test shall GB/T 14905 method, hose, between the layers of the adhesion strength between the outer layer and the reinforcing layer is not less than 1.4kN/m.

6.1.6.2 Wire reinforced hose adhesion performance

AI type and requirements and methods for testing the performance AII-sensitive adhesive layer with a wire reinforced hose outer cladding with 6.1.6.1. Take some do not Less than 380mm long hose, according to the following requirements Adhesion Test inner liner.

Table 3 provides the specifications of the ball placed in the lumen of the hose. End of the hose is connected to a vacuum source, and the other end plugged. Basically in the hose

The straight state, 17kPa absolute vacuum is applied, maintaining 5min. After 5min remains under vacuum, the hose along two different ways Respectively bent 180 ° to the table 2 in the minimum bend radius. The hose is bent back to basics straight state, still under vacuum, steel Ball rolling from one end to the other end. The ball can be freely rolled from one end to the other end of said inner liner layer and the reinforcing layer was separated, and determines Ineligible.

Table 3 Test improve the adhesion properties of the layer wire ball size in millimeters

Nominal size 568,111,316 Ball Specifications 3.5 4.5 6.0 7.5 9.5 12.0

6.2 Identification of performance

For the initial identification under this standard, all performance acceptance, and bending tests to identify performance requirements should be satisfied. Minimum sampling and provisions the test procedure continues in accordance with Table 4.

Table 4 Minimum sampling and subsequent test procedures

Test Test Sample No. connection 1 6.1.1a 6.2.1.1, and 6.1.2.

2 6.1.1a 6.2.1.2, and 6.1.2.

3 6.2.2.1 -

4 6.1.1a 6.2.2.2, and 6.1.4 5 6.2.2.3 -6 6.1.1a 6.2.2.4, and 6.1.3 7 6.1.1a 6.1.5, and 6.1.2 and 6.1.3 8 6.1.6 -9 6.1.1a Chapter 7 mounting a pipe joint or before the start of the test to aging.

6.2.1 Temperature Performance

6.2.1.1 High temperature performance

The hose portion of the hose or hose assembly is bent on the model, and the aging tank at 100 °C ± 2 °C, after 72h ± 2h after aging when straight, not its internal and external cracks, charring and fragmentation should appear. Radius of the test model should be consistent with the provisions of Table 2. An outer braided fiber cladding soft the outer surface of the tube is not feasible due to the visual inspection, can be free from cracks item.

After completion of the test, the hose assemblies shall be tested in accordance with the verification 6.1.2 pressure.

6.2.1.2 Low temperature performance

The hose and having radii as shown in Table 2 Model placed in an air circulating inside the rear through 70h ± 2h at -40 °C ± 2 °C, this temperature of the hose is bent 180 ° on the model, not the inner and outer hose cracks should appear. in the whole process. Hoses and model should be based on non-metallic table Surface support. 5s to be bent into a completed 3s. The outer surface of the fiber cladding outer braided hose is not feasible due to the visual inspection, the subject may be free from Check cracking project.

6.2.2 Environmental resistance

6.2.2.1 Oil

According to GB/T 1690-2006 experiment, samples were prepared from the inner liner and the outer cover ASTMIRM903 at 100 °C ± 2 °C of Oil immersed 70h ± 2h, taken out from, the measurement volume expansion should not exceed 100%.

6.2.2.2 Water

The hose or hose assembly is bent and placed on the model listed in Table 2 of the minimum bend radius of distilled water at room temperature regulator 168h ± 2h.

To the end portion is completely sealed during impregnation.

After the test, the hose assemblies for assembly 6.1.4 tensile strength test.

6.2.2.3 Ozone

The hose assembly on the model table listed the minimum bend radius of bend 2, and placed in an ozone test chamber, ± 2 deg.] C at ambient temperature for 40 °C Under standard atmospheric conditions through 70h ± 2h, the gas tank is composed of air and ozone, the ozone partial pressure of 100 mPa (100 per million parts 100 parts of ozone air). 7 times was observed with a magnifying glass, the hose should not have cracks. The test only applies to elastomeric outer hose coating.

6.2.2.4 Salt spray test

According to GB/T 10125 test. The hose assemblies to the vertical direction angle of 15 ° ~ 30 ° so as to support or suspend the salt spray exposure in 24h ± 1h. After this exposure, in addition to the joint wrinkles and identification imprint the deformed part red rust can not accept the outer metal corrosion. White Color corrosion products can be accepted.

After completion of the test, the hose assemblies 6.1.3 should burst strength test.

7.1 Preparation of the sample

7.1.1 Prior to cutting the hose, the longitudinal direction of the hose (the hose with the natural bending line due to the coil formed by) a draw (color significantly different the hose outer cover layer) line, see Figure 1.

FIG hose reticle 1

7.1.2 Sample hose assemblies hose cut to prepare a free length of the hose shown in Figure 2 and Table 5. The free length of the hose is finished soft Hose pipe length between the exposed pipe joint assembly.

7.1.3 linker manufacturer's instructions should be fitted on the hose.

7.2 Preconditioned

7.2.1 Salt spray regulation

Each of the sample assembly is first adjusted as follows, and then press 7.2.2 adjusted.

The end of the hose assembly of the sample plug, according to GB/T 10125 salt spray test method, exposed to salt spray 24h ± 1h.

After completion of the salt spray according to the adjusted start before high temperature aging test 7.2.2, the time interval should not exceed 168h.

7.2.2 High-temperature aging

Each specimen hose assembly is placed flat, aged 70h ± 2h at 100 ± 2 °C deg.] C in air. During the entire adjustment, each hose should be exposed to the lumen of the sample in air aging tank.

At least 2h with the hose assembly cooled to room temperature, but before high temperature aging after completing the 7.3 and 7.4 according to the flexural test start, Time interval should not exceed 168h.

7.3 in the test sample is mounted in the apparatus After preconditioning the sample, in 5 Figure 2 and Table predetermined manner mounted in the test apparatus. Installation procedures are as follows.

Flex test apparatus 2 of FIG.

TABLE 5 millimeters deflection test device

Hose free

Length ± 2

Nominal size

size

Position 1 Position 2 ABCRABCR ± 3 ± 3 ± 3 Reference ± 3 ± 3 ± 3 Reference 255 5,6 7,570,953,475,709,530 280 8,10,11 75 9,011,543,759,011,533 355 12,13SP, 13,15,16 75 100 125 56 75 100 125 46 7.3.1 flex tester movable manifold center of its travel, so that mark line is located in the top center of the connector "B" connected to the movable manifold Tube (see FIG. 2).

7.3.2 mounted connector "B" to the rear of the movable manifolds, then the joint "A" is connected to a stationary manifold, not imposing any twist connection, it should be Allowing its natural bent.

7.4 Test Procedure

7.4.1 Overview

Deflection from the center of the sample is obtained by moving the position of the stroke linker "B" from each side of the center to 75mm (dimension A in FIG. 2), i.e., the position "1" and the position "2" are alternately performed. At the same time, pressure is applied to the circulating air, the opening 60s, OFF 60s.

7.4.2 Flex/pressure cycling test parameters

7.4.2.1 The total deflection stroke 150mm ± 1.5mm.

7.4.2.2 Deflection stroke frequency

1.7Hz ± 0.1Hz.

7.4.2.3 Ambient temperature

26 °C ± 6 °C.

7.4.2.4 Inner pressure of the sample

1MPa ± 0.1MPa. Air pressure should alternate, all "open" 60s ± 5s, all "OFF" 60s ± 5s.

7.5 Bending test termination

Due to damage of the sample can lead to loss of air pressure, whereby the measurement can be the point of failure (the number of cycles Flexing). Air pressure is provided by cross for all "open" 60s ± 5s and full "off" 60s ± 5s applied. Through a 1.6mm + 0.05 0 mm diameter orifice again in 2min when pressurized to 1MPa ± 0.1MPa, the pressure loss can be referred to as system damage. The system does not before completing one million cycles Flexing it should be destroyed.