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CN-115771486-B - Electromechanical brake

CN115771486BCN 115771486 BCN115771486 BCN 115771486BCN-115771486-B

Abstract

Some embodiments of the present disclosure provide an electromechanical brake configured to pull a brake pad toward a brake disc by a piston under a drive motor, the electromechanical brake including a hysteresis data storage unit for storing rising interval function data about a rising interval in which a braking force increases as the piston moves toward the brake disc, and falling interval function data about a falling interval in which the braking force decreases as the piston moves away from the brake disc, a transition interval function data generating unit for generating data about a transition interval function for a transition interval in which the braking force is transmitted from any one of the rising interval or the falling interval to the other of the rising interval and the falling interval as a direction of movement of the piston changes, a position detecting unit, and a braking force calculating unit.

Inventors

  • LIN DONGHUAN

Assignees

  • 现代摩比斯株式会社

Dates

Publication Date
20260505
Application Date
20220901
Priority Date
20210908

Claims (10)

  1. 1. An electromechanical brake for causing a piston to pull a brake pad toward a brake disc under the influence of a drive motor, the electromechanical brake comprising: A hysteresis data storage unit configured to store rising interval function data regarding a rising interval in which a braking force increases as a piston moves toward the brake disc, and falling interval function data regarding a falling interval in which the braking force decreases as the piston moves away from the brake disc; A transition section function data generation unit configured to generate data on a transition section function of a transition section in which the braking force is converted from either one of the rising section or the falling section to the other one of the rising section and the falling section when a moving direction of the piston is changed; A position detecting unit for detecting the position of the piston, and And a braking force calculation unit configured to calculate the braking force based on the detected position of the piston.
  2. 2. The electromechanical brake according to claim 1, wherein the transition section function data generating unit includes a memory that stores transition section function data concerning the transition section.
  3. 3. The electromechanical brake according to claim 1, wherein the transition section function data generating unit includes a calculating unit that calculates the transition section function based on the detected position of the piston.
  4. 4. The electromechanical brake according to claim 1, wherein the braking force calculation unit calculates the braking force by a function having a larger function value among the transition section function and the descent section function when the moving direction of the piston is changed from a direction toward the brake disc to a direction away from the brake disc.
  5. 5. The electromechanical brake according to claim 1, wherein the braking force calculation unit calculates the braking force by 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 brake disc to a direction toward the brake disc.
  6. 6. The electromechanical brake according to claim 1, wherein the transition interval function has a positive slope.
  7. 7. The electromechanical brake according to claim 1, wherein the transition interval function is a linear function having a positive slope.
  8. 8. The electromechanical brake according to claim 1, wherein the plurality of transition functions between the rising interval and the falling interval are each linear functions having the same slope.
  9. 9. The electromechanical brake according to claim 1, wherein the differential value of the transition interval function is greater than the differential value of the rising interval function at any piston position and the differential value of the falling interval function at any piston position.
  10. 10. The electromechanical brake according to claim 1, wherein the hysteresis data storage unit stores a plurality of rising functions and a plurality of falling functions that are modified according to an amount of wear of the brake pad.

Description

Electromechanical brake Cross Reference to Related Applications The present application claims priority and benefit from korean patent application No. 10-2021-019776 filed on 8 of 9 of 2021, which is incorporated herein by reference in its entirety. Technical Field The present disclosure relates to an electromechanical brake. Background The statements in this section merely provide background information of the present disclosure and may not constitute prior art. Electromechanical brakes (Electro-MECHANICAL BRAKE, EMB) have been widely used. Electromechanical brakes were developed as electronic parking brakes (Electronic Parking Brake, EPB), but the field of use of brakes is expanding to foundation brakes instead of traditional hydraulic brakes. EMB is a device in which an actuator driven by a motor is mounted on a caliper to directly brake a vehicle by a motor driving force without a medium such as brake fluid. Since the mechanism of EMB is similar to Electronic Parking Brake (EPB), it differs from EPB only in that it is mainly used for foundation brakes, and thus EMB requires higher brake response and operation durability than EPB. In addition, compared with a hydraulic brake, the electromechanical brake has simpler structure, faster brake response speed and more accurate control, thereby improving the brake stability. The EMB equipped with the load sensor can accurately measure the clamping force. However, if the EMB is equipped with a load sensor, the design of the components to mount the sensor becomes complicated, and the manufacturing cost thereof increases. Furthermore, the size of the EMB may be inevitably increased due to the installation of the sensor. To prevent an increase in manufacturing cost and an increase in EMB size, a current sensor may be used instead of a load sensor to estimate the clamping force. The EMB may be designed such that the current sensor measures the current flowing through the motor generating the braking force, and estimates the clamping force based on the measured current value. However, the method of estimating the clamping force by measuring the current flowing through the motor is problematic in that the estimation accuracy is lowered due to the measurement noise of the current sensor, as compared with the case of using the load sensor. Fig. 11A, 11B, and 11C are schematic views showing the construction of a conventional electromechanical brake. Referring to fig. 11A, 11B and 11c, the emb includes a brake disc 11_c, a pair of brake pads 11_b provided on both sides of the brake disc 11_c, and a piston 11_a for pressing the brake pads 11_b toward the brake disc 11_c. As the piston 11_a moves toward the brake disc 11_c, the braking force increases. Even if the relative positions of the piston 11_a and the brake pad 11_b are the same, the braking force has different values according to the movement path of the piston 11_a. That is, the braking force of the position of the piston 11_a has hysteresis. Therefore, if the moving path of the piston 11_a is not considered, the braking force of the EMB cannot be accurately estimated. Disclosure of Invention In view of the above, the electromechanical brake according to one embodiment can estimate the clamping force with high accuracy by estimating the clamping force based on the position of the piston at which a specific current value is detected. The electromechanical brake according to one embodiment calculates the braking force by considering hysteresis of the braking force of the piston position, thereby more accurately calculating the braking force so as to control the electromechanical brake using the calculated braking force. The problems to be solved by the present disclosure are not limited to the above-described problems, and other problems not mentioned will be clearly understood by those skilled in the art from the following description. According to at least one embodiment, the present disclosure provides an electromechanical brake configured to pull a brake pad toward a brake disc by driving a motor, the electromechanical brake including a hysteresis data storage unit for storing ascending section function data regarding an ascending section, in which a braking force increases as the piston moves toward the brake disc, and descending section function data regarding a descending section, in which a braking force decreases as the piston moves away from the brake disc, a transition section function data generating unit for generating data regarding a transition section function for the transition section, in which the braking force is converted from any one of the ascending section or the descending section to a remaining section of the ascending section and the descending section as a direction of movement of the piston changes, a position detecting unit for detecting a position of the piston, and a braking force calculating unit for calculating the braking force based on the detected piston position. According to on