Structure, performance requirements and test methods of brake hose
1 Scope
This document specifies the structure, performance requirements, test methods and identification of brake hose, brake hose end fitting and brake hose assembly for automobiles, motorcycles, mopeds and trailers.
This document is applicable to hydraulic, pneumatic and vacuum brake hose and brake hose end fitting and brake hose assembly for automobiles, motorcycles, mopeds and trailers.
This document is not applicable to spiral pipes and high temperature gas transmission rubber hoses for automobiles.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 1690-2010 Rubber, vulcanized or thermoplastic—Determination of the effect of liquids
GB/T 7129-2001 Rubber or plastics hoses—Determination of volumetric expansion
GB/T 10125-2021 Corrosion tests in artificial atmospheres—Salt spray tests
GB 12981-2012 Motor vehicle brake fluids
GB/T 14905-2020 Rubber and plastics hoses—Determination of adhesion between components
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
brake hose
flexible hose used in a brake system to transfer fluid and gas energy to a brake or booster in brake system
3.2
brake hose end fitting
accessories attached to the end of brake hose for connection in addition to clamps
3.3
brake hose assembly
brake hose with brake hose end fitting
Note: The brake hose may be/not be provided with armor.
3.4
armor
protective device installed outside the brake hose for improving the scratch or impact resistance of the brake hose
3.5
free length
straight line length of the brake hose exposed between the hose end fittings when the brake hose assembly is in a plumb state
3.6
nominal inside diameter
inside diameter of brake hose expressed in millimeter
3.7
nominal outside diameter
outside diameter of brake hose expressed in millimeter
4 General requirements
4.1 The brake hose assembly used for the test shall be an unused product manufactured at least 24 hours ago. Before the test, the brake hose assembly shall be placed for at least 4h at 15°C–32°C.
4.2 The brake fluid used in the test of hydraulic brake hose assembly shall be HZY3 or HZY4 specified in GB 12981-2012, or other test media which shall be indicated in the test report.
4.3 Unless otherwise required, the test shall be conducted at room temperature of 15°C–32°C.
4.4 The positive and negative deviations are allowed for nominal inside diameter and nominal outside diameter. For convenience of reference, integers may be used. Among them, hydraulic brake hose and other rubber brake hose shall be expressed by nominal inside diameter, while pneumatic brake plastic hose and vacuum brake plastic hose shall be expressed by nominal outside diameter.
5 Hydraulic brake hose assembly
5.1 Structure
Hydraulic brake hose assembly consists of brake hose and brake hose end fittings, as well as accessories (such as armor, etc.). The brake hose and the brake hose end fitting shall be connected permanently, which shall be realized by crumpling or cold extrusion deformation of the hose by the fitting.
5.2 Performance requirements
The hydraulic brake hose assembly or corresponding parts shall be tested according to 5.3, and the test results shall meet the performance requirements specified in Table 1.
Table 1 Performance requirements for hydraulic brake hose assembly
S.N. Test item Unit Performance requirements Quantity/piece Test method
1 Internal hole throughput after necking a — All gauges pass within 3s without applying external force 44 5.3.1
2 Maximum expansion mL/m See Table 2 4 5.3.2
3 Bursting strength Inside diameter ≤ 3.2 mm MPa ≥49.0 5.3.3
Inside diameter > 3.2 mm ≥34.5
4 Compatibility of brake fluid Internal hole throughput after necking — All gauges pass within 3s without applying external force 4 5.3.4
Bursting
strength Inside diameter ≤ 3.2 mm MPa ≥49.0
Inside diameter > 3.2 mm ≥34.5
5 Flexural fatigue b h ≥35 4 5.3.5
6 Tensile strength Slow N ≥1 446 4 5.3.6
Fast ≥1 646 4
7 Water absorption Bursting strength Inside diameter ≤ 3.2 mm MPa ≥49.0 4 5.3.7
Inside diameter > 3.2 mm ≥34.5
Flexural fatigue h ≥35.0 4
Tensile strength Slow N ≥1 446 4
Fast ≥1 646 4
8 Cold resistance — No crack 1 5.3.8
9 Ozone resistance — No chap 1 5.3.9
10 Dynamic ozone resistance — No chap 1 5.3.10
11 High temperature pulse resistance Bursting strength Inside diameter ≤ 3.2 mm MPa ≥49.0 4 5.3.11
Inside diameter > 3.2 mm ≥34.5
12 Corrosion resistance of fitting — No corrosion of metal substrate 1 5.3.12
a If it is necessary to cut the hydraulic brake hose assembly for the test of internal hole throughput after necking, the number of test samples is 52, 8 of which are subjected to the test of internal hole throughput after necking.
b This test is only performed on hydraulic brake hose assemblies for frame and axle with relative motion parts.
Table 2 Maximum expansion
Nominal inside diameter/mm Test pressure/MPa Standard expansion hose/(mL/m) Low expansion hose/(mL/m)
≤3.2 6.9 ≤2.17 ≤1.08
10.3 ≤2.59 ≤1.38
20.0 ≤3.96 ≤2.00
>3.2–5.0 6.9 ≤2.82 ≤1.81
10.3 ≤3.35 ≤2.36
20.0 ≤5.48 ≤2.98
>5.0 6.9 ≤3.41 ≤2.69
10.3 ≤4.27 ≤3.84
5.3 Test methods
5.3.1 Internal hole throughput after necking
5.3.1.1 Gauge requirements
The structure and dimension of the gauge shall meet the requirements of Figure 1, and its mass shall meet those specified in Table 3.
If the gauge is fully inserted into the hose from the fitting at one end of the hydraulic brake hose assembly by not cutting the hose, the gauge may be lengthened or the handle may be removed, but the structure shall meet the requirements of Figure 1 and the mass shall meet those specified in Table 3.
If steel balls are used, the diameters shall meet those specified in Table 3.