Electro-mechanical brake
The present disclosure in some embodiments provides an electro-mechanical brake configured such that a piston pulls a brake pad toward a wheel disc by driving a motor, the electro-mechanical brake comprising: a hysteresis data storage unit storing rising-section function data on a rising section in which braking force increases as the piston moves toward the wheel disc, and falling-section function data on a falling section in which the braking force decreases as the piston moves away from the wheel disc; a transition section function data generating unit generating data on a transition section function for a transition section in which the braking force is transferred from any one of the rising section or the falling section to a remaining section of the rising and falling sections as a moving direction of the piston is changed; a position detection unit; and a braking force calculation unit.
1. An electro-mechanical brake configured such that a piston pulls a brake pad toward a wheel disc by driving a motor, the electro-mechanical brake comprising:
a hysteresis data storage unit storing rising-section function data on a rising section in which braking force increases as the piston moves toward the wheel disc, and falling-section function data on a falling section in which the braking force decreases as the piston moves away from the wheel disc;
a transition section function data generating unit generating data on a transition section function for a transition section in which the braking force is transferred from any one of the rising section or the falling section to a remaining section of the rising and falling sections as a moving direction of the piston is changed;
a position detection unit detecting a position of the piston; and
a braking force calculation unit calculating the braking force based on the detected position of the piston;
wherein the braking force calculation unit calculates the braking force by following a function having a larger function value among the transition section function and the falling section function, when a moving direction of the piston is changed from a direction towards the wheel disc to a direction away from the wheel disc.
2. The electro-mechanical brake of claim 1 , wherein the transition section function data generating unit comprises a memory storing transition section function data on the transition section.
3. The electro-mechanical brake of claim 1 , wherein the transition section function data generating unit comprises a calculation unit calculating the transition section function based on the detected position of the piston.
4. The electro-mechanical brake of claim 1 , wherein the transition section function has a positive slope.
5. The electro-mechanical brake of claim 1 , wherein the transition section function is a linear function having a positive slope.
6. The electro-mechanical brake of claim 1 , wherein all of a plurality of transition functions between the rising section and the falling section are linear functions having the same slope.
7. The electro-mechanical brake of claim 1 , wherein a differential value of the transition section function is greater than a differential value of the rising section function at any piston position and a differential value of the falling section function at any piston position.
8. The electro-mechanical brake of claim 1 , wherein the hysteresis data storage unit stores a plurality of rising functions and a plurality of falling function varying depending on a wear amount of the brake pad.
9. An electro-mechanical brake configured such that a piston pulls a brake pad toward a wheel disc by driving a motor, the electro-mechanical brake comprising:
a hysteresis data storage unit storing rising-section function data on a rising section in which braking force increases as the piston moves toward the wheel disc, and falling-section function data on a falling section in which the braking force decreases as the piston moves away from the wheel disc;
a transition section function data generating unit generating data on a transition section function for a transition section in which the braking force is transferred from any one of the rising section or the falling section to a remaining section of the rising and falling sections as a moving direction of the piston is changed;
a position detection unit detecting a position of the piston; and
a braking force calculation unit calculating the braking force based on the detected position of the piston;
wherein the braking force calculation unit calculates the braking force by following a function having a smaller function value among the transition section function and the rising section function, when the moving direction of the piston is changed from a direction away from the wheel disc to a direction towards the wheel disc.