GB/T 304.9-2021Spherical plain bearings—Part 9: General technical regulations (English PDF)

4.1 Classification

The classification of spherical plain bearings shall comply with the provisions of GB/T 304.1.

4.2 Identification code

The identification code of spherical plain bearings shall comply with the provisions of GB/T 304.2.

4.3 Appearance dimension

4.3.1 The appearance dimension of radial spherical plain bearings shall comply with the provisions of GB/T 9163.

4.3.2 The appearance dimension of angular contact spherical plain bearings shall comply with the provisions of GB/T 9164.

4.3.3 The appearance dimension of thrust spherical plain bearings shall comply with the provisions of GB/T 9162.

4.3.4 The appearance dimension of rod ends spherical plain bearings shall comply with the provisions of GB/T 9161.

4.4 Tolerance

4.4.1 The tolerance of radial spherical plain bearings shall comply with the provisions of GB/T 9163.

4.4.2 The tolerance of angular contact spherical plain bearings shall comply with the provisions of GB/T 9164.

4.4.3 The tolerance of thrust spherical plain bearings shall comply with the provisions of GB/T 9162.

4.4.4 The tolerance of rod ends spherical plain bearings shall comply with the provisions of GB/T 9161.

20CrMnMo, 20CrNiMo carburized steel specified in GB/T 3077; and G20CrMo, G20CrNiMo carburized bearing steel specified in GB/T 3203. The quality of heat treatment shall comply with the provisions of JB/T 14004.

4.8.2 Extrusion outer rings, gasket-inserted outer rings and rod end bodies are generally made of 45 or 35 high-quality carbon structural steels complying with the provisions of GB/T 699; and 35CrMo, 40Cr, 40CrNiMoA, 42CrMo quenched and tempered steels specified in GB/T 3077. For parts that need heat treatment, the quality of heat treatment shall comply with the provisions of JB/T 14004.

4.8.3 The ferrule and rod end body can also be made of other materials that meet the performance requirements; and the quality of heat treatment is determined by the user and the manufacturer through consultation.

4.9 Surface treatment

4.9.1 The surface of spherical plain bearing ferrules with sliding contact surface of steel/steel shall generally be treated with manganese phosphating; and the thickness and surface quality of the phosphating layer shall meet the requirements of product drawings; the sliding contact surface shall be coated with molybdenum disulfide.

4.9.2 The outer spherical surface of the inner ring of the self-lubricating spherical plain bearing shall be plated with hard chromium; and the thickness and surface quality of the coating shall meet the requirements of the product drawing.

4.9.3 The outer surface of the rod end shall adopt galvanized trivalent chromium passivation or other environmentally friendly anti-corrosion coatings; and the thickness and surface quality of the coating shall meet the requirements of the product drawing. After the neutral salt spray test is carried out according to the provisions of GB/T 10125 for no less than 48 hours, there shall be no red rust on the external surface of the rod end.

4.9.4 Other surface treatment requirements for spherical plain bearing parts shall be determined through negotiation between the manufacturer and the user.

4.10 Residual magnetism

The maximum value of residual magnetism of spherical plain bearings shall not exceed the provisions of Table 7.

The outer ring of the assembled rod end spherical plain bearing shall be closely matched with the rod end eye; and its circumferential, radial and axial directions shall not be loose. The outer ring of the installed radial spherical plain bearing is not allowed to expose the end face of the rod end eye. After the slotted outer ring type radial spherical plain bearing is installed into the rod end eye, the slotted position of the outer ring shall be perpendicular to the thread axis; and the deviation shall be no greater than ±10°. For products with marks, the direction of the typing surface on the eye of the rod end shall generally be consistent with the direction of the typing surface of the outer ring of the assembled radial spherical plain bearing.

4.15 Other technical requirements

The spherical plain bearings shall rotate and swing flexibly; and other requirements shall comply with the provisions of product drawings.

4.16 Detection method

4.16.1 Measurement of tolerances

4.16.1.1 The tolerance of spherical plain bearings shall be inspected after finishing, before surface treatment and slotting; and the measurement method shall be in accordance with the provisions of GB/T 307.2.

4.16.1.2 The deviation of the actual center height of the rod end can be replaced by measuring the distance between the bottom of the inner hole and the end of the rod end body plus the radius of the inner hole.

4.16.1.3 Thread tolerances are to be inspected with thread limit gauges of corresponding grades after surface treatment.

4.16.2 Measurement of radial clearance

4.16.2.1 The measurement of the radial clearance of self-lubricating slotted radial spherical plain bearings shall be in accordance with the provisions of JB/T 14003.

4.16.2.2 The measurement of the radial clearance of lubricated slotted radial spherical plain bearings shall be measured according to the following two methods according to the different sizes.

a) For bearings with a nominal inner diameter d<=80mm, the bearing needs to be installed in the corresponding ferrule (the upper limit deviation of the ferrule is the upper limit deviation value of M7 specified in GB/T 1800.2-2020; and the lower limit deviation is the upper limit deviation value - 5µm); sealed rings shall be removed before measuring the sealed bearings. Fix the inner ring; move the outer ring in the diameter direction for measurement. Measure at three positions 120° apart on the circumference, and the arithmetic mean value is the radial clearance. The measurement of radial clearance adopts load measurement; and the measurement load is in accordance with the provisions