QC/T 1191-2023Steering gear racks for passenger cars (English PDF)

3.1 edge hardness

hardness measured near the edge of the specimen with a durometer

Note: Considering influence factors such as the stability of the specimen under stress during test, the influence depth of the straightening of the outer surface of the specimen and the size of the indenter of the durometer, the position is generally selected at about 2mm from the outer edge of the indentation to the outer surface.

3.2 a quarter of D hardness

hardness at half of the radius

3.3 surface hardness

hardness measured directly by a durometer on the surface of rack material cylinder

Note: When steering gear manufacturers are more concerned about the surface hardness, they may choose to test the hardness at this position. However, because the indentation is curved when the hardness is detected at this position, the hardness value is not accurate enough. The hardness value shall be compensated according to the curvature radius of the material and the hardness testing standard.

4.1 General requirements

4.1.1

The racks of steering gear for passenger cars shall be manufactured, verified and validated in accordance with prescribed procedures and design specifications, drawings and process requirements.

4.1.2

The overall structure of a rack of steering gear for passenger car includes the threaded ends on both sides, gear milling section, ball screw, or polished rod.

4.1.3

Potential failure mode analysis and corresponding strength calculation shall be carried out in the design process of racks of steering gear for passenger cars.