GB/T 27546-2026Lifting appliances - Sheaves (English PDF)

4.2 Type

4.2.1 According to the manufacturing process of pulleys, they are classified as follows, and a typical schematic diagram is shown in Figure 2.

a) Cast pulleys;

b) Welding pulleys;

c) Double-width plate pressing pulley;

d) Rolling pulleys.

4.2.2 According to the type of bearing used, they are classified as follows, and a typical structural diagram is shown in Figure 3.

4.3 Basic Parameters The basic dimensions of the pulley rope groove cross section should conform to the provisions of Table 1, and the schematic diagram is shown in Figure 2. The wheel hub size and other detailed dimensions are determined by the pulley manufacturer based on the shaft size, bearing type, and the force and strength of the pulley. The diameter of the pulley shaft should preferably be selected from the following range (in millimeters). 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 90. 100,110,120,130,140,150,160,170,180,190,200,220,240.

6.1 Usage Conditions

6.1.1 The operating ambient temperature is -20°C to 60°C. Any temperature exceeding this range should be resolved through consultation between the user and the manufacturer.

6.1.2 The maximum skew angle when the wire rope enters or exits the pulley groove (i.e., the angle between the centerline of the wire rope and the plane perpendicular to the pulley axis). It should not exceed 5°.

6.2 Materials The mechanical properties of the pulley materials are shown in Table 3.

6.3 Welding and weld seams Welded pulleys and rolled pulleys shall meet the following requirements.

a) The welding materials shall be compatible with the materials being welded and shall comply with the provisions of GB/T 5117;

b) The weld bevel design shall conform to the requirements of GB/T 985.1 and GB/T 985.2;

c) Welds shall be visually inspected and shall be free from craters, spatter, slag, severe undercut, and surface cracks that affect performance and appearance quality. Defects should be identified, and non-destructive testing of critical welds should be performed if necessary.

6.4 Appearance and Surface Treatment

6.4.1 The surface roughness of the pulley rope groove shall not be lower than Ra in GB/T 1031 for rope grooves manufactured by machining. 12.5µm; for rope groove surfaces manufactured by rolling and pressing, the surface roughness should not be lower than Ra25µm as specified in GB/T 1031; the surface roughness of the inner bore of the pulley mounting bearing should also be 12.5µm. The surface roughness should not be lower than Ra3.2µm, and the roughness of other unprocessed surfaces should not be lower than Ra25µm in GB/T 1031.

6.4.2 The machined surfaces of pulleys and exposed parts such as spacers should be coated with anti-rust oil, and non-machined surfaces should be painted.

6.4.3 Cast pulleys, welded pulleys and rolled pulleys shall be subjected to stress relief treatment.

6.4.4 The surface of the welded pulley rope groove should be free of scratches and oxide scale after rolling.

6.4.5 The pressing part of the double-width plate pressing pulley should be smooth, flat, and free of wrinkles, cracks and burrs.

6.4.6 The machined surfaces of castings shall be free from defects such as sand holes, porosity, shrinkage cavities, cracks, and looseness, and the non-machined surfaces shall be free from defects that affect strength. defect.

6.4.7 The spokes of the pulley should be provided with lifting holes for the pulley.

6.5 Assembly

6.5.1 The assembled pulleys should rotate freely.

6.5.2 The recommended tolerance for the fit between the pulley body and the bearing outer diameter is M7 or P7.

6.5.3 The limit deviation of the groove bottom radius r shall conform to the provisions of Table

1.For other dimensional limit deviations, h14 shall apply to cast pulleys, and h14 shall apply to other pulleys. It should comply with the provisions of Table 4.

6.6 Geometric Tolerances The geometric tolerances of the pulleys are shown in Table 5.

6.7 Load-bearing capacity The load-bearing capacity of a pulley should be matched with the maximum tension of the largest diameter wire rope to which it is adapted.

6.8 Pulley Hardness The hardness of the pulley should meet the design requirements.

7.1 Test Conditions

7.1.1 The ambient temperature is measured to be between -20°C and 60°C using a thermometer.

7.1.2 The angle between the center line of the wire rope and the plane perpendicular to the pulley axis shall not exceed 5°.

7.2 Visual inspection Visual inspection includes, but is not limited to, the following items.

c) Appearance quality;

d) Surface roughness;

e) Assembly dimensions;

f) Geometric tolerances are measured using geometric tolerance measuring instruments;

g) Hardness was measured using a hardness tester.

7.3 Non-destructive testing of welds The results of magnetic particle testing shall be no lower than Grade 2 as specified in GB/T 26952.

7.4 Load-bearing capacity test The test shall be conducted in accordance with the test method of GB/T 5905.1.