Electromechanical brake and method of operation thereof

Abstract

The present application provides an electromechanical brake and a method for operating the same. The electromechanical brake according to the present embodiment includes a piston configured to advance and retreat to press a brake pad, a power conversion unit configured to receive a driving force from an actuator, convert the rotational motion into linear motion, and provide the linear motion to the piston, and a position adjustment portion configured to adjust a relative position of the piston with respect to the power conversion unit, wherein the power conversion unit includes a main shaft configured to receive the driving force from the actuator and rotate, and a nut coupled to the main shaft and configured to advance or retreat on an inner side of the piston by rotation of the main shaft in a first direction or a second direction, thereby advancing or retreating the piston, and the position adjustment portion includes an adjustment screw configured to be disposed on an outer side of the nut and rotate together with the nut, a first thread formed on an outer circumferential surface of the adjustment screw, a second thread formed on an inner circumferential surface of the piston and engaged with the first thread, and an adjuster configured to be disposed between the main shaft and the nut and rotate the nut and the adjustment screw in the first direction or the second direction by rotation of the main shaft, thereby advancing or retreating the relative position of the piston.

Description

Technical Field

[0001] This invention relates to electromechanical brakes and their operating methods, and more specifically, to an electromechanical disc brake and its operating method that utilizes the rotational driving force of a motor to achieve vehicle braking. Background Technology

[0002] Vehicles are always equipped with braking systems to perform braking. For the safety of drivers and passengers, various types of braking systems have been proposed.

[0003] Existing braking systems primarily utilize a mechanically connected booster to supply hydraulic pressure to the wheel cylinders when the driver depresses the brake pedal. However, a new generation of braking systems, electromechanical braking systems, has recently been developed. These systems receive the driver's braking intention via electrical signals and, based on this, activate transmission devices such as motors to provide braking force to the vehicle.

[0004] According to this electromechanical braking system, the rotational force of the motor is converted into linear motion through a motor and a reducer, thereby providing clamping pressure on the brake disc and thus performing vehicle service braking and parking braking.

[0005] On the other hand, brake pads, which are in direct contact with the brake discs and apply pressure, gradually wear down with repeated braking. To maintain the vehicle's braking performance despite brake pad wear, compensation is needed to address this wear. However, this increases the size of the braking system or its axial length, leading to a decrease in the vehicle's usability. Summary of the Invention

[0006] Technical problems to be solved

[0007] This embodiment provides an electromechanical braking system and its operating method that can maintain and improve the braking performance of a vehicle even when the brake pads are worn.

[0008] This embodiment provides an electromechanical braking system and its operating method that can stably perform vehicle braking even under various vehicle operating conditions.

[0009] This embodiment provides an electromechanical braking system and its operating method that reduce the size and weight of the vehicle, thereby improving its applicability and space utilization.

[0010] This embodiment provides an electromechanical braking system and its operating method that can easily compensate for brake pad wear through a simple structure.

[0011] This embodiment provides an electromechanical brake system and its operating method that reduces drag, improves braking performance, and suppresses braking noise and vibration.

[0012] means of solving technical problems

[0013] According to one aspect of the present invention, the provided electromechanical brake may include: a piston configured to move forward and backward to pressurize brake pads; a power conversion unit that receives driving force from an actuator and converts rotational motion into linear motion, which is provided to the piston; and a position adjustment unit that adjusts the relative position of the piston with respect to the power conversion unit, wherein the power conversion unit includes: a main shaft that receives driving force from the actuator and rotates; and a nut connected to the main shaft, which moves forward or backward inside the piston by rotation of the main shaft in a first direction or a second direction, thereby causing the piston to move forward or backward; the position adjustment unit includes: an adjusting screw disposed outside the nut and rotating together with the nut; a first thread formed on the outer peripheral surface of the adjusting screw; a second thread formed on the inner peripheral surface of the piston and engaging with the first thread; and an adjuster disposed between the main shaft and the nut, which rotates the nut and the adjusting screw in the first or second direction by rotation of the main shaft, thereby causing the relative position of the piston to move forward or backward.

[0014] The aforementioned adjuster may include: a flange extending radially on the outer circumferential surface of the main shaft; a first protrusion protruding from the flange; and a second protrusion protruding from the nut, which is engaged by the first protrusion when the main shaft rotates in a first direction, guiding the rotation of the nut and the adjusting screw in the first direction, thereby advancing the relative position of the piston.

[0015] When the vehicle's brakes are released, the first angle between the first protrusion and the second protrusion can be greater than the second angle by which the first protrusion rotates from the state of brake release to the state of brake application.

[0016] The aforementioned regulator may also include a third protrusion formed on the aforementioned flange, and when the aforementioned main shaft rotates in the second direction, the aforementioned second protrusion is locked by the aforementioned third protrusion, guiding the rotation of the aforementioned nut and the aforementioned adjusting screw in the second direction, thereby causing the relative position of the aforementioned piston to retract.

[0017] When the vehicle is braking, the third angle between the second protrusion and the third protrusion can be greater than the fourth angle by which the third protrusion rotates from the braking state of the vehicle to the braking release state of the vehicle.

[0018] The inner circumferential surface of the nut provided may be formed with an internal thread. The spindle includes: a first end on one side, the outer circumferential surface of which is formed with an external thread that engages with the internal thread; a second end on the other side, which is connected to the actuator; and a central portion located between the first end and the second end, wherein the flange is fixedly disposed on the outer circumferential surface of the central portion.

[0019] The first and third protrusions are separate from each other and protrude from the front surface of the flange facing the nut, while the second protrusion protrudes from the back surface of the nut facing the front surface of the flange.

[0020] The aforementioned adjusting screw can be formed as a hollow cylinder to cover a portion of the outer side of the aforementioned nut. At least a portion of the parts of the adjusting screw and the aforementioned nut that are in contact with each other are formed as planar anti-rotation surfaces.

[0021] It may also include: a release spring, one end of which is supported by the first protrusion and the other end by the second protrusion, and is compressed by rotation of the main shaft in the first direction.

[0022] It may also include: an electronic control unit that controls the operation of the actuator; and a sensing unit that measures the clamping force between the brake disc and the brake pads that rotate together with the wheel.

[0023] When the clamping force between the brake disc and the brake pads, as measured by the aforementioned sensing unit, is less than a set value while the vehicle is braking, the aforementioned electronic control unit can determine that the brake pads are worn, and thus enter a first mode that advances the relative position of the pistons.

[0024] When the braking force between the brake disc and the brake pads measured by the aforementioned sensing unit is greater than a set value when the vehicle's brakes are released, the electronic control unit can determine that there is drag and thus enter a second mode that causes the relative position of the piston to retract.

[0025] In the first mode described above, the operation of the actuator can be controlled to rotate the main shaft in the first direction from the vehicle's brake release state to the vehicle's braking state, and trigger further rotation of the main shaft in the first direction, causing the first protrusion to connect and rotate with the second protrusion, thereby guiding the rotation of the nut and the adjusting screw in the first direction. Through the rotation of the adjusting screw in the first direction, the relative position of the piston with respect to the nut is advanced.

[0026] After the first mode described above, the electronic control unit can return the main shaft or the first protrusion to its original position when the vehicle's brakes are released.

[0027] In the second mode described above, the operation of the actuator can be controlled to rotate the main shaft in the second direction from the vehicle's braking state to the vehicle's braking release state, and trigger further rotation of the main shaft in the second direction, causing the third protrusion to rotate in contact with the second protrusion, thereby guiding the rotation of the nut and the adjusting screw in the second direction. Through the rotation of the adjusting screw in the second direction, the piston's relative position to the nut is retracted.

[0028] Invention Effects

[0029] According to the electromechanical braking system and its operating method of this embodiment, even if the brake pads wear, the braking performance of the vehicle can be maintained and improved.

[0030] The electromechanical braking system and its operating method according to this embodiment can stably perform vehicle braking even under various operating conditions of the vehicle.

[0031] The electromechanical braking system and its operating method according to this embodiment reduce size and weight, thereby improving the applicability of the vehicle and enabling better space utilization.

[0032] According to the electromechanical brake system and its working method of this embodiment, the wear of brake pads can be compensated through a simple structure.

[0033] According to the electromechanical brake system and its working method in this embodiment, drag phenomenon is reduced, thereby improving braking performance and suppressing braking noise and vibration. Attached Figure Description

[0034] Figure 1 This is a side cross-sectional view showing the electromechanical brake according to this embodiment.

[0035] Figure 2 This is an enlarged side cross-sectional view showing the main parts of the electromechanical brake according to this embodiment.

[0036] Figure 3 This is an exploded perspective view showing the main parts of the electromechanical brake according to this embodiment.

[0037] Figure 4 yes Figure 2 The cross-sectional view along the A-A' direction shows the positions of the first protrusion, the second protrusion, and the third protrusion before braking or when the vehicle is released from braking.

[0038] Figure 5 This is a side cross-sectional view showing the operation of the electromechanical brake according to this embodiment under vehicle braking conditions.

[0039] Figure 6yes Figure 5 The cross-sectional view along the B-B' direction shows the positions of the first protrusion, the second protrusion, and the third protrusion when the vehicle is braking.

[0040] Figure 7 This is a side cross-sectional view of the operation of the electromechanical brake according to this embodiment in the first mode state used to compensate for brake pad wear.

[0041] Figure 8 yes Figure 7 The cross-sectional view along the C-C' direction shows the positions of the first protrusion, the second protrusion, and the third protrusion in the first mode state.

[0042] Figure 9 This is a side cross-sectional view of the operation of the electromechanical brake according to this embodiment in the vehicle's brake release state after the first mode.

[0043] Figure 10 yes Figure 9 The cross-sectional view along the D-D' direction shows the positions of the first, second, and third protrusions of the vehicle in the brake-released state after the first mode.

[0044] Figure 11 This is a side cross-sectional view showing the operation of the electromechanical brake according to this embodiment in the second mode state for reducing drag.

[0045] Figure 12 yes Figure 11 The cross-sectional view along the E-E' direction shows the positions of the first protrusion, the second protrusion, and the third protrusion in the second mode state.

[0046] Figure 13 This is an enlarged side cross-sectional view showing the main parts of an electromechanical brake according to a modified embodiment of the present invention. Detailed Implementation

[0047] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided to fully convey the spirit of the invention to those skilled in the art. The present invention is not limited to the embodiments disclosed below and can be implemented in other ways. For clarity, parts unrelated to the description are omitted from the drawings, and the dimensions of constituent elements are sometimes exaggerated to aid understanding.

[0048] Figure 1 This is a side cross-sectional view showing the electromechanical brake 100 according to this embodiment.

[0049] Reference Figure 1The electromechanical brake 100 according to this embodiment may include a bracket (not shown) that provides a pair of pads 11, 12 to pressurize a brake disc (not shown) that rotates together with the wheel; a caliper housing 20 that is slidably provided on the bracket to operate the pair of pads 11, 12; a piston 110 that is retractably provided inside the caliper housing 20; an actuator (not shown) that generates and provides a driving force for moving the piston 110; a power conversion unit 120 that receives the rotational driving force provided by the actuator, converts it into linear motion, and transmits it to the piston 110 to realize the axial retractable movement of the piston 110; a position adjustment unit 130 that adjusts the relative position of the piston 110 with respect to the power conversion unit 120 to compensate for the wear of the brake pads 10 or reduce drag; a sensing unit 140 that measures the contact force between the brake disc and the brake pads 10 or the fastening force of the brake pads 10; and an electronic control unit (not shown) that controls the operation of the actuator based on the information provided by the sensing unit 140.

[0050] Brake pads 10 are respectively attached to the inner surfaces of a pair of pads 11 and 12. The pair of pads 11 and 12 are composed of an inner pad 11 and an outer pad 12, and are slidably mounted on the bracket. The inner pad 11 is configured such that its outer surface is flush with the front surface of the piston 110. Figure 1 The outer pad 12 is configured such that its outer surface is in contact with the finger portion 22 of the caliper housing 20.

[0051] The caliper housing 20 includes a finger-like portion 22 for actuating the outer pad 12 and a cylinder portion 21 with a piston 110, and is slidably fastened to the bracket. When braking the vehicle, the caliper housing 20 slides from the bracket and moves toward the brake disc side due to the reaction force generated by the movement of the piston 110. This allows the outer pad 12 to approach the brake disc side via the finger-like portion 22, thereby pressurizing the brake disc.

[0052] Figure 2 as well as Figure 3 This is an enlarged side cross-sectional view and an exploded perspective view showing the main parts of the electromechanical brake 100 according to the embodiment, with reference to Figures 1 to 3 Piston 110 can be configured to be open rear side ( Figure 1 as well as Figure 2The piston 110 is cup-shaped (on the right side) and can be slidably inserted inside the cylinder section 21. The piston 110 receives power via an actuator (not shown) and a power conversion unit 120 (described later) to pressurize the inner pad 11 against the brake disc. A second thread 133 is formed on the inner circumferential surface of the piston 110, engaging with a first thread 132 formed on the outer circumferential surface of the adjusting screw 131 (described later). For adjusting the relative position of the piston 110 with respect to the spindle 121 or the nut 125 via the position adjustment section 130, refer to... Figures 4 to 12 This will be discussed later.

[0053] The power conversion unit 120 includes a main shaft 121 that receives driving force from an actuator and rotates, a nut 125 disposed inside a piston 110 and screwed to the main shaft 121, which moves forward with the piston 110 when the main shaft 121 rotates in a first direction or moves backward with the piston 110 when the main shaft 121 rotates in a second direction, and a plurality of balls 129 clamped between the main shaft 121 and the nut 125. This power conversion unit 120 can be composed of a ball screw type conversion device that converts the rotational motion of the main shaft 121 into linear motion.

[0054] The first direction of rotation of the spindle 121 described below refers to the direction of rotation in which the nut 125 moves forward by rotating the spindle 121. The second direction of rotation of the spindle 121 refers to the direction of rotation opposite to the first direction, which is the direction of rotation in which the nut 125 moves backward by rotating the spindle 121.

[0055] The spindle 121 can be divided into a first end 121a on one side with an external thread 122 formed on its outer circumferential surface, a second end 121c on the other side connected to an actuator and receiving driving force, and a central portion 121b disposed between the first end 121a and the second end 121c, where the flange 136 described later is fixed. The first end 121a of the spindle 121 can be inserted into the inside of the nut 125, and the second end 121c can be provided with a bearing 150 for enabling smooth rotation of the flange 136 described later, and a sensing part 140 for sensing the load applied to the spindle 121 to measure the fastening force between the brake disc and the brake pad 10.

[0056] The nut 125 can be formed as a hollow cylinder so that the first end 121a of the main shaft 121 can be inserted into it. The inner circumferential surface can be formed with an internal thread 126 that engages with the external thread 122 of the main shaft 121 via balls (not shown). Furthermore, the outer side of the nut 125 can be provided with an adjusting screw 131 (described later) that covers at least a portion of the outer circumferential surface of the nut 125. The outer circumferential surface of the nut 125 can be formed with an anti-rotation surface 125a, at least a portion of which is flat to prevent relative rotation with the adjusting screw 131. Ball screw type power conversion devices are widely used and well-known technologies, so a detailed description of their operation is omitted.

[0057] The actuator (not shown) may comprise a motor and a reduction gear with multiple reduction gears. It can receive power from a power supply located in the vehicle to generate and provide driving force. The actuator is connected to the second end 121c of the main shaft 121, thereby transmitting the generated driving force to the rotational motion of the main shaft 121. The actuator may be located on the outside of the caliper housing 20, and the reduction gear may employ various structures such as planetary gear assemblies or worm gear structures to reduce the power speed of the motor before supplying it to the main shaft 121.

[0058] The position adjustment unit 130 is configured to adjust the relative position of the piston 110 relative to the power conversion unit 120, so that the relative position of the piston 110 moves forward to compensate for the wear of the brake pads 10, or to move the relative position of the piston 110 backward to reduce drag.

[0059] The position adjustment unit 130 may include an adjusting screw 131 disposed outside the nut 125 and rotating together with the nut 125, a first thread 132 formed on the outer peripheral surface of the adjusting screw 131, a second thread 133 formed on the inner peripheral surface of the piston 110 and engaging with the first thread 132, and an adjuster 135 disposed between the main shaft 121 and the nut 125, which, by rotating the main shaft 121, causes the nut 125 and the adjusting screw 131 to rotate in a first direction to advance the relative position of the piston 110, or causes the nut 125 and the adjusting screw 131 to rotate in a second direction opposite to the first direction to retract the relative position of the piston 110.

[0060] The first direction of rotation of the nut 125 or adjusting screw 131 described below is the same as the first direction of rotation of the main shaft 121 described above, indicating the direction of rotation in which the piston 110 is advanced by rotating the adjusting screw 131. Furthermore, the second direction of rotation of the nut 125 or adjusting screw 131 is the opposite direction of rotation to the first direction, the same as the second direction of rotation of the main shaft 121 described above, indicating the direction of rotation in which the piston 110 is retracted by rotating the adjusting screw 131.

[0061] The adjusting screw 131 is configured to cover the front side of the nut 125, and a first thread 132 is formed on its outer peripheral surface. The adjusting screw 131 may have an anti-rotation surface 131a formed on at least a portion of its inner peripheral surface that contacts the nut 125, so as to prevent relative rotation while rotating together with the nut 125. When the nut 125 rotates via the adjuster 135 (described later), the adjusting screw 131 rotates together with the nut 125, and can transmit the rotational force of the nut 125 to the piston 110 side. The adjusting screw 131 is clamped between the nut 125 and the piston 110, thereby absorbing the load generated when the nut 125 contacts the piston 110, and preventing deformation and wear of components such as the nut 125 and piston 110 under heavy loads.

[0062] A first thread 132 can be formed on the outer peripheral surface of the adjusting screw 131, and a second thread 133 can be formed on the inner peripheral surface of the piston 110. The first thread 132 and the second thread 133 are configured to mesh with each other. In this way, the adjusting screw 131 and the piston 110, which rotate and move linearly together with the nut 125, are screwed together. The nut 125 moves linearly together with the adjusting screw 131 and the piston 110. Thus, when the vehicle brakes normally, the nut 125, the adjusting screw 131, and the piston 110 can move forward together, or when the vehicle brakes are released, the nut 125, the adjusting screw 131, and the piston 110 can move backward together. At the same time, the piston 110 and the adjusting screw 131 can rotate relative to each other, so that by rotating the nut 125 and the adjusting screw 131 in the first direction, the piston 110 can move forward relative to the nut 125 or the main shaft 121, and by rotating the nut 125 and the adjusting screw 131 in the opposite second direction, the piston 110 can move backward relative to the nut 125 or the main shaft 121.

[0063] Adjuster 135 rotates nut 125 and adjusting screw 131, thereby advancing or retracting the relative position of piston 110 with respect to nut 125. Adjuster 135 may include a flange 136 fixed to the central portion 121b of spindle 121 and extending radially, and a protrusion formed on the front surface of flange 136 (to... Figure 2 The first protrusion 137 (on the left side of the reference surface) is formed on the back of the nut 125 (with the reference surface). Figure 2The right side of the reference flange 136 and the second protrusion 138 that is triggered and guides the rotation of the nut 125 and the adjusting screw 131 in the first direction when the main shaft 121 rotates in the first direction, and the third protrusion 139 that is formed on the front surface of the flange 136 and is triggered and guides the rotation of the nut 125 and the adjusting screw 131 in the second direction when the main shaft 121 rotates in the second direction, are locked by the second protrusion 138.

[0064] A flange 136 extends radially from the central portion 121b of the main shaft 121 and is fixed to the main shaft 121, thus allowing it to rotate integrally with the main shaft 121. The front surface of the flange 136 (with...) Figure 2 The left side of the flange 136 (as referenced) is separated from each other by a predetermined angle and has a first protrusion 137 and a third protrusion 139, which will be described later. Figure 2 The right side (based on the reference) may be provided with a bearing 150 to allow the flange 136 to rotate smoothly and to prevent wear between the flange 136 and surrounding component elements.

[0065] The first protrusion and the third protrusion 139 protrude from the front surface of the flange 136 facing the nut 125 (to... Figure 2 (based on the left side), so that when the main shaft 121 rotates, it can rotate together with the flange 136 about the main shaft 121 as an axis. The second protrusion 138 is formed on the back side of the nut 125 facing the flange 136 (with the left side as a reference), so that when the main shaft 121 rotates, it can rotate together with the flange 136 about the main shaft 121 as an axis. Figure 2 (based on the right side), thus being held in place by the first protrusion 137 or the third protrusion 139, which can guide the rotation of the nut 125 and the adjusting screw 131.

[0066] Figure 4 yes Figure 2 The cross-sectional view along the A-A' direction shows the positions of the first to third protrusions 139 before or after vehicle braking. (Refer to...) Figure 4 A first protrusion 137 and a third protrusion 139 are provided on the front surface of the flange 136, which are spaced apart from each other at an angle, and a second protrusion 138 provided on the back of the nut 125 can be disposed therebetween.

[0067] Specifically, in the pre-operation state or the vehicle's brake-released state, the angle (hereinafter referred to as the "first angle") between the first protrusion 137 on the front surface of the flange 136 and the second protrusion 138 on the back of the nut 125 is formed to be greater than the rotation angle of the first protrusion 137 from the vehicle's brake-released state to the vehicle's braking state (refer to...). Figure 6(Hereinafter referred to as the "second angle"). If the second angle ② is greater than the first angle ①, during normal vehicle braking, the second protrusion 138 is also locked by the first protrusion 137, triggering the rotation of the nut 125 and the adjusting screw 131 in the first direction. This causes the piston 110 relative to the nut 125 or the main shaft 121 to advance, rapidly increasing the clamping force between the piston 110 and the pad, resulting in a braking force greater than the driver's braking requirement, and causing drag, thus reducing vehicle driving stability and fuel economy. Therefore, by making the first angle ① greater than the second angle ②, during normal vehicle braking, the first protrusion 137 and the second protrusion 138 can be prevented from contacting each other, thereby maintaining a uniform relative position of the piston 110 relative to the nut 125 or the main shaft 121, achieving better driver braking operability and driving stability.

[0068] Furthermore, when the vehicle is braking, the angle between the second protrusion 138 on the back of the nut 125 and the third protrusion 139 on the front surface of the flange 136 (refer to...) Figure 6 (Hereinafter referred to as the "third angle") is formed by a rotation angle greater than the third protrusion 139 from the braking state of the vehicle to the braking release state of the vehicle (refer to...). Figure 4 as well as Figure 6 (Hereinafter referred to as the "fourth angle"). If the fourth angle ④ is greater than the third angle ③, during normal vehicle brake release, the second protrusion 138 is also locked by the third protrusion 139, triggering the second-direction rotation of the nut 125 and the adjusting screw 131. As a result, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 moves backward, reducing the clamping force between the piston 110 and the pad, thus applying a braking force less than the driver's braking requirement, posing a risk of a safety accident. Therefore, by making the third angle ③ greater than the fourth angle ④, during normal vehicle brake release, the second protrusion 138 and the third protrusion 139 can be prevented from contacting each other, thereby maintaining a uniform relative position of the piston 110 with respect to the nut 125 or the main shaft 121, thus achieving better driver braking operability and driving stability.

[0069] The sensing unit 140 is configured to detect the contact force or clamping force between the brake disc and the brake pads 10. The sensing unit 140 may be configured as a force sensor, which measures the clamping force between the brake disc and the brake pads 10 by sensing the load on the spindle 121 or the actuator, but is not limited to this type of device. The sensing unit 140 sends the measured clamping force information of the brake pads 10 to the electronic control unit, which can determine the wear or drag of the brake pads 10 based on the clamping force information measured by the sensing unit 140.

[0070] The operation method of the electromechanical brake 100 system according to this embodiment will be described below.

[0071] Figure 5 This is a side cross-sectional view showing the operation of the electromechanical brake 100 according to this embodiment under vehicle braking conditions. Figure 6 yes Figure 5 A cross-sectional view along the B-B' direction shows the positions of the first protrusion 137, the second protrusion 138, and the third protrusion 139 when the vehicle is under braking conditions.

[0072] Reference Figure 2 , Figures 4 to 6 When performing normal braking actions such as service braking or parking braking, without entering the first or second mode described later, it can be done from... Figure 2 as well as Figure 4 The brake release state shown Figure 5 as well as Figure 6 The braking state shown is in operation.

[0073] Specifically, when the driver applies pressure to the brake pedal (not shown) to brake the vehicle, the pedal displacement sensor (not shown) detects the driver's braking intention as an electrical signal and sends it to the electronic control unit. Based on its control of the actuator, the electronic control unit ensures that the brake disc and brake pads 10 are in close contact, thereby achieving vehicle braking.

[0074] When the vehicle brakes, the actuator operates, causing the main shaft 121 to rotate in a first direction. As the main shaft 121 rotates in the first direction, the nut 125 moves forward, and the piston 110 also moves towards the pad side. The brake pad 10, mounted on the pad, approaches and presses against the brake disc, thereby generating a clamping force that triggers the vehicle's braking.

[0075] At this time, as the main shaft 121 rotates in the first direction, the first protrusion 137 of the flange 136 on the main shaft 121 rotates by a second angle ② from the vehicle's brake-released state to the vehicle's braking state. In the vehicle's brake-released state, the first angle ① between the first protrusion 137 of the flange 136 and the second protrusion 138 of the nut 125 becomes larger, so that under normal braking conditions, the first protrusion 137 of the flange 136 and the second protrusion 138 of the nut 125 do not contact each other. Therefore, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 can be maintained at a certain level.

[0076] When releasing the vehicle brakes, it can be done from... Figure 5 as well as Figure 6 The braking state shown is towards Figure 2 as well as Figure 4 The diagram shows the operation in the brake release state. Specifically, by operating the actuator, the main shaft 121 rotates in the second direction. As the main shaft 121 rotates in the second direction, the nut 125 retracts, and simultaneously the piston 110 separates from the pad and retracts as well. The brake pad 10, mounted on the pad, separates from the brake disc, thereby releasing the vehicle's brakes. With the rotation of the main shaft 121 in the second direction, the first protrusion 137 on the flange 136 of the main shaft 121 returns to its original position.

[0077] The first mode of the electromechanical brake 100 according to this embodiment, which compensates for the wear of the brake pads 10 so as to maintain the braking performance of the vehicle even if the brake pads 10 are worn, will be described below.

[0078] If the contact force or fastening force between the brake disc and brake pad 10 measured by the sensing unit 140 during vehicle braking is less than the set normal range value, the electronic control unit determines that the brake pad 10 is worn, and can then enter the first mode to compensate for the wear.

[0079] Figure 7 This is a side cross-sectional view showing the operation of the electromechanical brake 100 according to this embodiment in a first mode state for compensating for wear of the brake pads 10. Figure 8 yes Figure 7 The cross-sectional view along the C-C' direction shows the positions of the first protrusion 137, the second protrusion 138, and the third protrusion 139 in the first mode state.

[0080] Reference Figure 7 as well as Figure 8 To enter the first mode, the electronic control unit controls the actuator to rotate the spindle 121 in the first direction. At this time, the electronic control unit triggers rotation of the spindle 121 in the first direction, similar to the rotation used in normal braking mode (see reference). Figure 5 as well as Figure 6 The second angle) compared to a further rotation in the first direction (more than) Figure 4 The first protrusion 137 on the flange 136 of the main shaft 121 engages with and rotates with the second protrusion 138 on the nut 125. The second protrusion 138 is engaged by the first protrusion 137 and rotates together in the first direction, thereby also triggering the rotation of the nut 125 and the adjusting screw 131 in the first direction. By rotating the nut 125 and the adjusting screw 131 in the first direction, the relative position of the piston 110 with respect to the nut 125 can advance, thereby compensating for the wear of the brake pad 10.

[0081] After the first mode of compensating for the wear of the brake pads 10 ends, the electromechanical brake 100 according to this embodiment returns to the state before the vehicle's brakes are released or before braking begins.

[0082] Figure 9 This is a side cross-sectional view showing the operation of the electromechanical brake 100 according to this embodiment in the brake-released state of the vehicle after the first mode. Figure 10 yes Figure 9 A cross-sectional view along the D-D' direction shows the positions of the first protrusion 137, the second protrusion 138, and the third protrusion 139 in the brake-released state of the vehicle after the first mode.

[0083] Reference Figure 9 as well as Figure 10 After compensating for the wear of the brake pads 10 in the first mode, the electronic control unit controls the operation of the actuator, triggering the rotation of the main shaft 121 in the second direction. Specifically, as... Figure 2 as well as Figure 4 As shown, the actuator rotates the main shaft 121 in a second direction, returning it to its state before the vehicle's brakes are released or engaged. As described above, when a further rotation of the main shaft 121 in the first direction is triggered in the first mode, the electronic control unit can rotate the main shaft 121 in the second direction by an amount equivalent to the further rotation in the first direction triggered in the first mode, thereby returning the main shaft 121 and the nut 125 to their original positions.

[0084] After executing the first mode, the main shaft 121, which returns to its original position, rotates to a second angle when braking the vehicle again. This allows it to compensate for the wear of the brake pads 10 by adjusting the relative position of the piston 110 with respect to the main shaft 121 or the nut 125, thereby enabling stable braking of the vehicle.

[0085] The following describes how the electromechanical brake 100 according to this embodiment performs a second mode to reduce the drag phenomenon that occurs when the piston 110 does not quickly return to its original position after vehicle braking.

[0086] When the braking force or clamping force between the brake disc and brake pad 10 measured by the sensing unit 140 in the vehicle's brake-released state is greater than the set normal range value, the electronic control unit determines that there is a drag phenomenon in which the piston 110 has not returned to its original position, and thus can enter the second mode.

[0087] Figure 11 This is a side cross-sectional view showing the operation of the electromechanical brake 100 according to this embodiment in a second mode state for reducing drag. Figure 12 yes Figure 11 The cross-sectional view along the E-E' direction shows the positions of the first protrusion 137, the second protrusion 138, and the third protrusion 139 in the second mode state.

[0088] Reference Figure 11 as well as Figure 12 In order to enter the second mode, the electronic control unit controls the actuator to rotate the spindle 121 in the second direction. At this time, the electronic control unit triggers a further rotation in the second direction (exceeding) compared to the rotation of the spindle 121 in the second direction used for the normal brake release state. Figure 4 The third protrusion 139 on the flange 136 of the main shaft 121 is engaged by the second protrusion 138 on the nut 125. The second protrusion 138 is engaged by the third protrusion 139, causing them to rotate together in the second direction, thereby also triggering rotation of the nut 125 and the adjusting screw 131 in the second direction. Through the rotation of the nut 125 and the adjusting screw 131 in the second direction, the relative position of the piston 110 with respect to the nut 125 can be retracted, thereby separating the piston 110 from the pad and reducing drag.

[0089] The electromechanical brake according to a modified embodiment of the present invention will now be described.

[0090] The following description of the electromechanical brake according to a modified embodiment of the present invention is the same as that of the electromechanical brake 100 according to this embodiment described above, except for the parts further described by separate reference numerals. To avoid repetition, the description is omitted.

[0091] Figure 13 This is an enlarged side cross-sectional view showing the main parts of the electromechanical brake 100 according to a modified embodiment of the present invention, with reference to... Figure 13 A separation spring 210 may be provided between the first protrusion 137 and the second protrusion 138 of the regulator 135.

[0092] One end of the release spring 210 is supported by a first protrusion 137, and the other end is supported by a second protrusion 138. During normal vehicle braking, the spring is compressed between the first protrusion 137 and the second protrusion 138 due to the rotation of the main shaft 121 in the first direction. For vehicle braking, the nut 125 and piston 110 advance, bringing the brake disc and brake pads 10 into contact. However, in the event of an actuator failure or power supply interruption, the vehicle brakes need to be automatically released for passenger safety. Therefore, during vehicle braking, as the first protrusion 137 and second protrusion 138 approach each other, the release spring 210 is compressed. If the actuator operation is interrupted, the elastic restoring force of the release spring 210 presses the first protrusion 137 back to its original position, triggering the rotation of the main shaft 121 in the second direction. The nut 125 and main shaft 121 then retract, thereby releasing the vehicle brakes.

[0093] like Figure 13As shown, the release spring 210 can be made of a disc spring, but is not limited to this. As long as the two ends are supported by the first protrusion 137 and the second protrusion 138 respectively and are compressed during vehicle braking to generate an elastic restoring force, it can be made of various materials and structures.

Claims

1. An electromechanical brake, comprising: The piston is designed to move forward and backward in order to pressurize the brake pads; The power conversion unit receives driving force from the actuator and converts the rotary motion into linear motion, which is then supplied to the piston. as well as The position adjustment unit adjusts the relative position of the piston with respect to the power conversion unit. The aforementioned power conversion unit includes: The main shaft, which receives driving force from the aforementioned actuator and rotates; and The nut, connected to the main shaft, moves forward or backward inside the piston as the main shaft rotates in a first or second direction, thereby causing the piston to move forward or backward. The aforementioned position adjustment unit includes: The adjusting screw, which is positioned outside the nut to prevent relative rotation, rotates together with the nut. The first thread is formed on the outer circumferential surface of the aforementioned adjusting screw; A second thread is formed on the inner circumferential surface of the piston and engages with the first thread; and An adjuster, located between the main shaft and the nut, rotates the main shaft to rotate the nut and the adjusting screw in a first or second direction, thereby causing the relative position of the piston to advance or retract. The above regulator includes: A flange is formed by extending radially along the outer peripheral surface of the aforementioned main shaft; The first protrusion is formed on the aforementioned flange; and The second protrusion, which protrudes from the nut, is engaged by the first protrusion when the main shaft rotates in the first direction, guiding the rotation of the nut and the adjusting screw in the first direction, thereby advancing the relative position of the piston. When the vehicle's brakes are released, the first angle between the first protrusion and the second protrusion is greater than the second angle of rotation of the first protrusion from the state of brake release to the state of brake application. The aforementioned regulator also includes a third protrusion formed on the aforementioned flange. The second protrusion is engaged by the third protrusion when the main shaft rotates in the second direction, guiding the rotation of the nut and the adjusting screw in the second direction, thereby causing the relative position of the piston to retract. When the vehicle is braking, the third angle between the second protrusion and the third protrusion is greater than the fourth angle of rotation of the third protrusion from the braking state of the vehicle to the braking release state of the vehicle.

2. The electromechanical brake according to claim 1, wherein, An internal thread is formed on the inner circumferential surface of the nut. The aforementioned spindle includes: The first end on one side has an external thread on its outer peripheral surface that engages with the aforementioned internal thread; The second end on the other side is connected to the aforementioned actuator; and The central portion, which is located between the first end and the second end, The aforementioned flange is fixedly disposed on the outer peripheral surface of the aforementioned central portion.

3. The electromechanical brake according to claim 2, wherein, The first and third protrusions are separated from each other and protrude from the front surface of the flange facing the nut. The second protrusion is formed on the back side of the nut, which faces the front surface of the flange.

4. The electromechanical brake according to claim 1, wherein, The aforementioned adjusting screw is formed into a hollow cylindrical shape to cover a portion of the outer side of the aforementioned nut. The aforementioned adjusting screw and the aforementioned nut each have at least a portion of their interlocking parts formed as a planar anti-rotation surface.

5. The electromechanical brake according to claim 1, wherein, Also includes: The release spring is supported at one end by the first protrusion and at the other end by the second protrusion, and is compressed by rotation of the main shaft in the first direction.

6. The electromechanical brake according to claim 1, wherein, Also includes: An electronic control unit controls the operation of the aforementioned actuators; as well as The sensing unit measures the clamping force between the brake disc and the brake pads, which rotate together with the wheel.

7. A method for operating an electromechanical brake, wherein the electromechanical brake is the electromechanical brake as described in claim 6, wherein, When the clamping force between the brake disc and the brake pads, as measured by the aforementioned sensing unit, is less than a set value while the vehicle is braking, the electronic control unit determines that the brake pads are worn and enters a first mode that advances the relative position of the pistons.

8. The method of operating the electromechanical brake according to claim 7, wherein, When the braking force between the brake disc and the brake pads measured by the aforementioned sensing unit is greater than a set value when the vehicle's brakes are released, the electronic control unit determines that there is drag and enters a second mode that causes the relative position of the pistons to retract.

9. The method of operating the electromechanical brake according to claim 7, wherein, In the first mode described above, the operation of the actuator is controlled to rotate the main shaft in the first direction from the vehicle's brake release state to the vehicle's braking state, and to trigger further rotation of the main shaft in the first direction, so that the first protrusion and the second protrusion come into contact and rotate, thereby guiding the rotation of the nut and the adjusting screw in the first direction. Through the rotation of the adjusting screw in the first direction, the relative position of the piston with respect to the nut is advanced.

10. The method of operating the electromechanical brake according to claim 9, wherein, After the first mode described above, the electronic control unit returns the main shaft or the first protrusion to its original position in the vehicle's brake-released state.

11. The method of operating the electromechanical brake according to claim 8, wherein, In the second mode described above, the operation of the actuator is controlled to rotate the main shaft in the second direction from the vehicle's braking state to the vehicle's braking release state, and to trigger further rotation of the main shaft in the second direction, causing the third protrusion to rotate in contact with the second protrusion, thereby guiding the rotation of the nut and the adjusting screw in the second direction. Through the rotation of the adjusting screw in the second direction, the relative position of the piston with respect to the nut is retracted.

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