Cam brake

At present, cam brakes are used in the pneumatic brake systems of all domestic cars and some foreign cars, and most of them are designed to be hoofed. The cam brake uses a cam instead of a brake wheel cylinder to act on the two brake shoes, and the air is usually rotated by the air pressure.

When braking, the brake adjusting arm drives the camshaft to rotate under the action of the push rod of the brake air chamber 6, so that the two brake shoes are pressed against the brake drum to brake. Due to the central symmetry of the cam profile and the axial symmetry of the two-hoof structure and the installation, the displacement of the corresponding points on the two hooves caused by the rotation of the cam must be equal. The sling brake actuated by the axis-fixed cam is an isometric brake, and the friction of the brake drum against the brake shoe causes the end of the hoof to force away from the brake cam, closer to the end of the hoof Cam. Therefore, although the hoof has an auxiliary effect and has a decreasing effect from the hoof, it is this difference that makes the driving force of the brake bristles with lower braking performance less than the hoof with low braking efficiency. The driving force is such that the braking torques of the two hooves are equal. Wedge Brakes The arrangement of the two hoofs in a wedge brake can be a hoof. 

The actuating device of the brake wedge itself as the brake shoe actuating member may be mechanical, hydraulic or pneumatic. The arcuate faces of the ends of the two brake shoes are respectively floated on the bottom surfaces of the straight grooves of the outer end faces of the plunger 3 and the plunger 6. The inner end faces of the plungers 3 and 6 are both inclined faces which are in contact with the rollers 4 supported in the grooves on both sides of the spacer 5. When braking, the wheel cylinder piston 15 pushes the brake wedge 13 inwardly under the action of hydraulic pressure. The latter in turn causes the two rollers to roll inwardly along the slanting side of the plunger, while pushing the two plungers 3 and 6 outwardly in the bore of the brake shoe 7 a certain distance, thereby pressing the brake shoe against the brake drum.