The increasing and decreasing force of brake shoes refer to the effect of brake shoes on the brake drum during the braking process. When the opening direction of the brake shoe is the same as the rotation direction of the brake drum, this type of brake shoe is called the leading shoe, which has an increasing force effect and helps to enhance the braking effect. On the contrary, when the opening direction of the brake shoe is opposite to the rotation direction of the brake drum, this type of brake shoe is called a slave shoe, which has a force reducing effect and helps to reduce the braking effect.
In the specific working process, hydraulic pressure causes the brake shoes to press against the brake drum, thereby generating braking torque and helping the vehicle decelerate or stop. For example, when the brake drum reverses, the friction force of the left shoe strengthens the braking effect, and the left shoe is the leading shoe (increasing momentum shoe) at this time; The friction force of the right hoof weakens the braking effect, and at this time, the right hoof is a subordinate hoof (reducing force hoof).