Hengyang Heavy Industry pneumatic caliper disc brake QP25.4-D six springs

2) Inspection of brake disc size

As shown in Figure 3, A represents the thickness of the brake disc (45mm for new discs). When the thickness of the brake disc is ≤ 39mm, it is recommended to replace it with a new friction plate and brake disc; 13 is the limit value for brake disc wear (B=37mm). When the thickness of the brake disc is less than 37mm, the brake disc must be replaced (when measuring the thickness of the thin part of the brake disc, it should be avoided to measure at the edge of the brake disc due to burrs); C is the total thickness of the friction plate, and the new plate is 30mm; D is the thickness of the base plate, D=8mm: E is the small thickness of the friction material, E=3mm: F is the small allowable value of the total thickness of the friction material and the base plate. When D=8mm, F: 11mm.

The width of the contact area of the brake disc can still be used until the wear limit value (37mm) is reached when:

① There are small spots distributed on the surface (A1 in Figure 4).

② A radial crack with a depth and width less than 1.5mm, and a crack length less than 3/4 of the width of the contact area of the friction plate (B1 in Figure 4).

③ A circular groove with a depth of less than 1.5mm (C1 in Figure 4). If the crack penetrates into the ventilation and cooling channels of the brake disc or radially penetrates the width of the friction plate contact area (D1 in Figure 4), the brake disc must be replaced.

The brake disc is maintenance free and does not require surface polishing when replacing the friction plate, but polishing is better. For example, when there are severe grooves on the friction surface of the brake disc, polishing can increase the contact area between the friction plate and the brake disc. To meet safety requirements, the small thickness of the polished brake disc must be greater than 39mm.