Electromechanical brakes and their operating methods

Abstract

This invention discloses an electromechanical brake and its operating method. The electromechanical brake according to this embodiment may include: a piston, movably disposed to press a brake pad; a power conversion unit, receiving driving force from an actuator to convert rotational motion into linear motion and provide it to the piston; and a position adjustment unit, adjusting the relative position of the piston relative to the power conversion unit. The power conversion unit includes: a main shaft, receiving driving force from the actuator and rotating; and a nut, connected to the main shaft, and moving forward or backward inside the piston by rotation of the main shaft in a first or second direction, thereby moving the piston forward or backward. The position adjustment unit includes: an adjusting screw, disposed outside the nut and rotating with the nut; a first thread formed on the outer circumferential surface of the adjusting screw; a second thread formed on the inner circumferential surface of the piston and engaging with the first thread; and an adjuster, disposed between the main shaft and the nut, and compressing or expanding back to its original shape when the rotation of the main shaft exceeds a preset rotation amount, so that the nut and the adjusting screw rotate in the first or second direction, thereby moving the relative position of the piston forward or backward.

Description

Technical Field

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

[0002] Vehicles must be equipped with braking systems to perform braking, and various types of braking systems have been proposed for the safety of drivers and passengers.

[0003] Traditional braking systems primarily use a mechanically connected booster to provide the necessary hydraulic pressure to the wheel cylinders when the driver depresses the brake pedal. However, as a next-generation braking system, an electromechanical braking system is currently under development. This system receives an electrical signal representing the driver's braking intention and operates an electric motor, among other things, to provide braking force to the vehicle.

[0004] This electromechanical braking system converts the rotational force of a motor into linear motion through a motor and a reducer, thereby providing clamping pressure on the brake disc and performing the vehicle's service and parking brakes.

[0005] On the other hand, the brake pads, which directly contact and press against the brake discs of the vehicle, gradually wear down with repeated braking operations. In order to maintain the vehicle's braking performance even with brake pad wear, it is necessary to compensate for brake pad wear. However, in this case, the size or axial length of the braking system increases, resulting in a reduction in vehicle applicability. Summary of the Invention

[0006] (a) Technical problems to be solved

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

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

[0009] This embodiment aims to provide an electromechanical braking system and its operation method that can improve the applicability of a vehicle by reducing its size and weight and ensuring the space utilization of the vehicle.

[0010] This embodiment aims to provide an electromechanical brake system and its operation method that can easily compensate for brake pad wear with a simple structure.

[0011] This embodiment aims to provide an electromechanical brake system and its operation method that can improve braking performance by reducing drag and suppressing braking noise and vibration.

[0012] (II) Technical Solution

[0013] According to one aspect of the invention, an electromechanical brake can be provided, comprising: a piston movably disposed to press a brake pad; a power conversion unit receiving a driving force from an actuator to convert rotational motion into linear motion and provide it to the piston; and a position adjustment unit adjusting the relative position of the piston with respect to the power conversion unit, the power conversion unit comprising: a main shaft receiving a driving force from the actuator and rotating thereon; and a nut connected to the main shaft and moving forward or backward inside the piston by rotation of the main shaft in a first or second direction, thereby moving the piston forward or backward; the position adjustment unit comprising: an adjusting screw disposed outside the nut and rotating with the nut; a first thread formed on the outer circumferential surface of the adjusting screw; a second thread formed on the inner circumferential surface of the piston and engaging with the first thread; and an adjuster disposed between the main shaft and the nut, and compressing or expanding back to its original shape when the rotation of the main shaft exceeds a preset rotation amount, so that the nut and the adjusting screw rotate in the first or second direction, thereby moving the relative position of the piston forward or backward.

[0014] The adjuster may include: a flange formed radially extending from the outer circumferential surface of the spindle; and a torsion spring supported at one end by the nut and at the other end by the flange.

[0015] From the moment the vehicle's brakes are released to the moment the vehicle is braked, the torsion spring can be compressed according to the amount of rotation of the main shaft in a first direction. The elastic restoring force of the torsion spring according to the amount of rotation in the first direction is less than the threaded engagement force between the adjusting screw and the piston.

[0016] The inner circumferential surface of the nut may be formed with an internal thread, and the spindle may include: a first end on one side, with an external thread on the outer circumferential surface that engages with the internal thread; a second end on the other side, connected to the actuator; and a central portion located between the first end and the second end, wherein the flange may be fixedly disposed on the outer circumferential surface of the central portion.

[0017] The position adjustment part may further include: a connecting cover, which engages the adjusting screw and the nut.

[0018] The electromechanical brake may further include: an electronic control unit for controlling the operation of the actuator; and a sensing unit for measuring the bonding force between the brake disc, which rotates with the wheel, and the brake pad.

[0019] When the vehicle is braking, if the force between the brake disc and the brake pad measured by the sensing unit is less than a preset value, the electronic control unit can determine that the brake pad is worn and enter a first mode that moves the relative position of the piston forward.

[0020] When the vehicle's brakes are released, if the force between the brake disc and the brake pad measured by the sensing unit is greater than a preset value, the electronic control unit can determine that there is resistance and enter a second mode that moves the relative position of the piston backward.

[0021] In the first mode, the operation of the actuator can be controlled to rotate the main shaft in a first direction from the vehicle's brake release state to the vehicle's braking state, thereby compressing the torsion spring and causing the main shaft to rotate an additional amount in the first direction beyond the preset rotation. Furthermore, the elastic restoring force of the torsion spring can guide the rotation of the nut and the adjusting screw in the first direction, so that the relative position of the piston with respect to the nut can be moved forward by the rotation of the adjusting screw in the first direction.

[0022] In the second mode, the operation of the actuator can be controlled to rotate the main shaft in a second direction from the vehicle's braking state to the vehicle's braking release state, thereby expanding the torsion spring and causing the main shaft to generate an additional second-direction rotation exceeding the preset rotation amount. Furthermore, the second-direction rotation of the nut and the adjusting screw can be guided by the elastic restoring force of the torsion spring, so that the relative position of the piston with respect to the nut is moved backward by the second-direction rotation of the adjusting screw.

[0023] (III) Beneficial Effects

[0024] The electromechanical braking system and its operation method according to this embodiment can maintain and improve the braking performance of a vehicle even when the brake pads are worn.

[0025] The electromechanical braking system and its operating method according to this embodiment can stably perform vehicle braking under various operating conditions.

[0026] The electromechanical braking system and its operation method according to this embodiment can improve the applicability of a vehicle by reducing its size and weight, and ensure the space utilization of the vehicle.

[0027] The electromechanical brake system and its operation method according to this embodiment can easily compensate for brake pad wear with a simple structure.

[0028] The electromechanical braking system and its operating method according to this embodiment can improve braking performance by reducing resistance and suppressing braking noise and vibration. Attached Figure Description

[0029] Figure 1 This is a lateral cross-sectional view of the electromechanical brake according to this embodiment.

[0030] Figure 2 This is an enlarged side cross-sectional view showing the main part of the electromechanical brake according to this embodiment.

[0031] Figure 3 This is an exploded perspective view showing the main parts of the electromechanical brake according to this embodiment.

[0032] Figure 4 This is a side cross-sectional view showing the operation of the electromechanical brake according to this embodiment under the braking state of the vehicle.

[0033] Figure 5 This is a side cross-sectional view showing the operation of the electromechanical brake according to this embodiment in a first mode state for compensating for wear of the brake pads.

[0034] Figure 6 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.

[0035] Figure 7 This is an enlarged side cross-sectional view showing the main part of the electromechanical brake according to a modified embodiment of the present invention. Detailed Implementation

[0036] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. These 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 described below and may be embodied in other forms. In the drawings, for clarity of illustration, parts unrelated to the description may be omitted, and for aid of understanding, the dimensions of components may be enlarged.

[0037] Figure 1 This is a lateral cross-sectional view of the electromechanical brake 100 according to this embodiment.

[0038] Reference Figure 1The electromechanical brake 100 according to this embodiment may include: a carrier (not shown) having a pair of pads 11, 12 for pressing a brake disc (not shown) that rotates with the wheels of the vehicle; a caliper housing 20 slidably mounted on the carrier to operate the pair of pads 11, 12; a piston 110 movable back and forth 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 and converts the rotational driving force into linear motion and transmits it to the piston 110, thereby realizing the axial back and forth 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 wear of the brake pad 10 or reduce drag; a sensing unit 140 that measures the adhesion force between the brake disc and the brake pad 10 or the bonding force of the brake pad 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.

[0039] A pair of pads 11 and 12 are configured such that brake pads 10 are respectively attached to their inner surfaces. The pair of pads 11 and 12 consist of an inner pad 11 and an outer pad 12 and are slidably mounted on a 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 contacts the finger portion 22 of the caliper housing 20, with the left side surface as a reference.

[0040] The caliper housing 20 includes a finger-like portion 22 for operating the outer pad 12 and a cylinder portion 21 for mounting the piston 110, and is slidably coupled to the bracket. When the vehicle brakes, the caliper housing 20 slides from the bracket and moves toward the brake disc by the reaction force caused by the movement of the piston 110. As a result, the outer pad 12 moves closer to the brake disc via the finger-like portion 22, thereby pressing the brake disc.

[0041] Figure 2 and 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 as rear-side ( Figure 1 and Figure 2 The piston 110 has a cup-shaped opening on the right side and can be slidably inserted into the cylinder body 21. Furthermore, the piston 110 receives power via the actuator and power conversion unit 120 described below, thereby enabling it to press the inner pad 11 towards the brake disc. The inner circumferential surface of the piston 110 may have a second thread 133 formed, which engages with a first thread 132 formed on the outer circumferential surface of the adjusting screw 131 described below. (See below for reference.) Figures 4 to 6 The operation of adjusting the relative position of the piston 110 with respect to the spindle 121 or nut 125 via the position adjustment unit 130 is described.

[0042] 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 threadedly connected to the main shaft 121, for moving forward with the piston 110 by rotation of the main shaft 121 in a first direction, or moving backward with the piston 110 by rotation of the main shaft 121 in a second direction; and a plurality of balls 129 sandwiched between the main shaft 121 and the nut 125. This power conversion unit 120 can be configured as a ball screw type conversion device that converts the rotational motion of the main shaft 121 into linear motion.

[0043] The first direction of rotation of the spindle 121 described below refers to the direction of rotation in which the nut 125 moves forward due to the rotation of the spindle 121. The second direction of rotation of the spindle 121 is the rotation in the opposite direction to the first direction, which refers to the direction of rotation in which the nut 125 moves backward due to the rotation of the spindle 121.

[0044] 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 to receive driving force; and a central portion 121b, disposed between the first end 121a and the second end 121c, and the flange 136 described below is fixed to the central portion 121b. 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 smooth rotation of the flange 136 described below, and a sensing part 140 for sensing the load applied to the spindle 121 to measure the bonding force between the brake disc and the brake pad 10.

[0045] The nut 125 can be formed as a hollow cylinder so that the first end 121a of the spindle 121 can be inserted into the inside of the nut 125, and the inner circumferential surface of the nut 125 can be formed with an internal thread 126, which engages with the external thread 122 of the spindle 121 through a ball (not shown). Additionally, an adjusting screw 131 can be provided on the outside of the nut 125, and the adjusting screw 131 covers at least a portion of the outer circumferential surface of the nut 125. At least a portion of the outer circumferential surface of the nut 125 can be provided with a planar anti-rotation surface 125a to prevent relative rotation with the adjusting screw 131. Ball screw type power conversion devices are widely used and well-known technologies; therefore, a detailed description of operation will be omitted.

[0046] The actuator (not shown) may include a motor and a reduction gear with multiple reduction gears, and may receive power from a power supply located in the vehicle to generate and provide driving force. The actuator is connected to a second end 121c of the main shaft 121, thereby enabling the generation of driving force to be transmitted 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 of the motor and provide it to the main shaft 121.

[0047] The position adjustment unit 130 adjusts the relative position of the piston 110 relative to the power conversion unit 120, so that the relative position of the piston 110 is moved forward to compensate for the wear of the brake pad 10, or the relative position of the piston 110 is moved backward to reduce the resistance phenomenon.

[0048] The position adjustment part 130 may include: an adjustment screw 131 disposed on the outside of the nut 125 and rotating together with the nut 125; a first thread 132 formed on the outer peripheral surface of the adjustment 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 spindle 121 and the nut 125, which compresses or expands according to the amount of rotation of the spindle 121, causing the nut 125 and the adjustment screw 131 to rotate in a first direction to move the relative position of the piston 110 forward, or causing the nut 125 and the adjustment screw 131 to rotate in a second direction opposite to the first direction to move the relative position of the piston 110 backward.

[0049] The rotation of the nut 125 or adjusting screw 131 in the first direction described below is the same direction of rotation as the rotation of the main shaft 121 described above, meaning the rotation direction in which the piston 110 is moved forward by rotating the adjusting screw 131. Furthermore, the rotation of the nut 125 or adjusting screw 131 in the second direction, which is the opposite direction to the first direction, is the same direction of rotation as the rotation of the main shaft 121 described above, meaning the rotation direction in which the piston 110 is moved backward by rotating the adjusting screw 131.

[0050] The adjusting screw 131 is configured to cover the front portion of the nut 125, and a first thread 132 is formed on its outer peripheral surface. At least a portion of the inner peripheral surface of the adjusting screw 131, in contact with the nut 125, is formed as a planar anti-rotation surface 131a, which prevents relative rotation between the adjusting screw 131 and the nut 125 while allowing the adjusting screw 131 to rotate together with the nut 125. When the nut 125 is rotated by the adjusting mechanism 135, the adjusting screw 131 can transmit the rotational force of the nut 125 to the piston 110 side while rotating together with the nut 125. The adjusting screw 131 is clamped between the nut 125 and the piston 110, thereby absorbing the load generated when the nut 125 and piston 110 are in contact, thus preventing deformation and wear of components such as the nut 125 and piston 110 under heavy loads.

[0051] 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 mesh with each other. As described above, the adjusting screw 131, which rotates and moves linearly with the nut 125, is threadedly engaged with the piston 110, and the nut 125, the adjusting screw 131, and the piston 110 move linearly together. Thus, during normal vehicle braking, the nut 125 can move forward together with the adjusting screw 131 and the piston 110, or when the vehicle brakes are released, the nut 125 can move backward together with the adjusting screw 131 and the piston 110. Meanwhile, the piston 110 and the adjusting screw 131 can rotate relative to each other. Therefore, 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 direction in the second direction, the piston 110 can move backward relative to the nut 125 or the main shaft 121.

[0052] Adjuster 135 rotates nut 125 and adjusting screw 131, thereby enabling the relative position of piston 110 with respect to nut 125 or spindle 121 to move forward or backward. Adjuster 135 may include: flange 136, fixed to the center portion 121b of spindle 121 and extending radially; torsion spring 137, disposed between nut 125 and flange 136, to elastically support nut 125 with respect to flange 136, and to compress or expand to its original shape when spindle 121 or flange 136 exceeds a preset rotation amount, thereby guiding rotation of nut 125 and adjusting screw in a first or second direction.

[0053] Flange 136 extends radially from the center portion 121b of spindle 121 and is fixed to spindle 121 to be able to rotate integrally with spindle 121. On the rear surface of flange 136 (with... Figure 2 A bearing 150 may be provided on the right side surface (based on the reference), the bearing 150 being used to allow the flange 136 to rotate smoothly and to prevent wear between the flange 136 and surrounding components.

[0054] One end of the torsion spring 137 can be inserted into and fixed to the outer circumferential surface of the nut 125, and the other end can be inserted into and fixed to the flange 136. The torsion spring 137 remains compressed or expanded within a preset rotation amount, for example, the rotation amount of the main shaft 121 between the vehicle's brake release state and braking state, and compresses or expands to return to its original shape when the preset rotation amount is exceeded, thereby guiding the rotation of the nut 125 and the adjusting screw 131 in a first direction or a second direction.

[0055] Specifically, when transitioning from the pre-operation state or the vehicle's brake-released state to the vehicle's braking state, the elastic restoring force based on the amount of rotation of the main shaft 121 in the first direction can be less than the threaded engagement force between the adjusting screw 131 and the piston 110. Therefore, during normal vehicle braking, even if the main shaft 121 and flange 136 rotate in the first direction, the torsion spring 137 can remain compressed, thereby maintaining a constant relative position with respect to the nut 125 or the piston 110 of the main shaft 121.

[0056] However, as described below, when the first mode of compensating for wear of the brake pad 10 is executed, and the rotation of the main shaft 121 for braking the vehicle exceeds the first directional rotation amount, the elastic restoring force of the torsion spring 137 will be greater than the threaded engagement force between the adjusting screw 131 and the piston 110. This causes the torsion spring 137 to expand and return to its original shape, and the expansion of the torsion spring 137 generates rotation of the nut 125 and the adjusting screw 131 in the first directional direction. Therefore, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 can be moved forward. Furthermore, as described below, when the second mode is executed to reduce resistance, and the rotation of the main shaft 121 for brake release exceeds the second directional rotation amount, the elastic restoring force of the torsion spring 137 will be greater than the threaded engagement force between the adjusting screw 131 and the piston 110. This causes the torsion spring 137 to compress and return to its original shape, and the compression of the torsion spring 137 generates rotation of the nut 125 and the adjusting screw 131 in the second directional direction. Therefore, the relative position of the piston 110 with respect to the nut 125 or the spindle 121 can be moved backward. Hereinafter, reference will be made to... Figures 4 to 6 This will be described in detail.

[0057] Furthermore, after the nut 125 and piston 110 move forward to bring the brake disc into contact with the brake pad 10 for vehicle braking, the vehicle's brakes need to be self-released to ensure passenger safety in the event of an actuator failure or power supply interruption. Therefore, during vehicle braking, the torsion spring 137 is compressed by the rotation of the main shaft 121 and flange 136 in a first direction, and when the actuator operation is interrupted or the power supply is interrupted, the main shaft can rotate in a second direction by the elastic restoring force of the torsion spring 137. This allows the nut 125 and main shaft 121 to move backward to release the vehicle's brakes.

[0058] The sensing unit 140 is configured to measure the adhesion or bonding force between the brake disc and the brake pad 10. The sensing unit 140 may be configured as a force sensor, etc., that senses the load on the spindle 121 or actuator to measure the bonding force between the brake disc and the brake pad 10, but is not limited to such devices. The sensing unit 140 sends the measured bonding force information of the brake pad 10 to the electronic control unit, which can determine the wear or resistance of the brake pad 10 based on the bonding force information measured by the sensing unit 140.

[0059] The operation method of the electromechanical brake 100 system according to this embodiment will be described below.

[0060] Figure 4 This is a side cross-sectional view showing the operation of the electromechanical brake 100 according to this embodiment under the braking state of the vehicle.

[0061] Reference Figure 2 and Figure 4 When the vehicle's service brake or parking brake is not engaged in the first or second mode of normal braking as described below, it can be used from... Figure 2 The brake release state operation shown is as follows Figure 4 The braking state is shown.

[0062] Specifically, when the driver applies pedal force to the brake pedal (not shown) to brake the vehicle, the pedal displacement sensor (not shown) detects the electrical signal indicating the driver's braking intention and sends it to the electronic control unit. The electronic control unit controls the operation of the actuator based on this electrical signal, thereby causing the brake disc and brake pad 10 to come into close contact, thus achieving vehicle braking.

[0063] When the vehicle brakes, the main shaft 121 rotates by a preset amount in the first direction through the operation of the actuator. The nut 125 moves forward due to the rotation of the main shaft 121 in the first direction. Similarly, the piston 110 moves forward towards the pad side. The brake pad 10 mounted on the pad comes close to and adheres tightly to the brake disc, thereby generating a contact force, which in turn generates braking force on the vehicle.

[0064] At this time, the main shaft 121 rotates in the first direction, and the torsion spring 137 is compressed. However, from the vehicle's brake release state to the vehicle's braking state, the elastic restoring force of the torsion spring 137, generated by the preset rotation amount in the first direction, is less than the threaded engagement force between the adjusting screw 131 and the piston 110. Therefore, under normal braking conditions, the nut 125 and the adjusting screw 131 will not rotate. Thus, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 can remain constant.

[0065] When the vehicle's brakes are released, it can be... Figure 4 The braking state operation shown is as follows Figure 2 The brake release state is shown. Specifically, the main shaft 121 rotates in the second direction by the operation of the actuator, and the nut 125 moves backward due to the rotation of the main shaft 121 in the second direction. At the same time, the piston 110 also separates from the pads 11 and 12 and moves backward. The brake pads 10 mounted on the pads 11 and 12 separate from the brake disc, thereby releasing the vehicle's brakes. At this time, the amount of rotation of the main shaft 121 in the second direction corresponds to the amount of rotation of the main shaft 121 in the first direction under normal braking conditions. Therefore, the torsion spring 137 will also return to its original shape due to the rotation of the main shaft 121 in the second direction.

[0066] The first mode will be described below. In the first mode, the electromechanical brake 100 according to this embodiment compensates for the wear of the brake pad 10 so as to maintain the braking performance of the vehicle even when the brake pad 10 is worn.

[0067] When the vehicle is braking, if the contact force or bonding force between the brake disc and the brake pad 10 measured by the sensing unit 140 is less than a preset normal range value, the electronic control unit can determine that the brake pad 10 is worn, and thus enter the first mode to compensate for the wear of the brake pad 10.

[0068] Figure 5 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 pad 10.

[0069] Reference Figure 5To enter the first mode, the electronic control unit controls the operation of the actuator, causing the main shaft 121 to rotate in a first direction. At this time, the electronic control unit causes the main shaft 121 to rotate an additional amount in the first direction beyond the preset rotation for normal vehicle braking. The torsion spring 137 is further compressed by this additional rotation in the first direction compared to normal vehicle braking, at which point the elastic restoring force of the torsion spring 137 is greater than the threaded engagement force between the adjusting screw 131 and the piston 110. As the torsion spring 137 expands to return to its original shape, rotation in the first direction is generated between the nut 125 and the adjusting screw 137, thereby shifting the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 forward, thus compensating for wear on the brake pad 10.

[0070] After the first mode of compensating for the wear of the brake pad 10 ends, the electromechanical brake 100 according to this embodiment rotates the main shaft 121 in the second direction by an amount corresponding to the rotation of the main shaft 121 in the second direction under normal braking conditions, thereby restoring the vehicle to its state before braking release or braking operation. In other words, although an additional rotation of the main shaft 121 in the first direction is generated during the execution of the first mode compared to normal braking conditions, after the first mode ends, the main shaft 121 is rotated in the second direction only by an amount corresponding to the rotation of the main shaft 121 under normal braking or braking release conditions, so that the main shaft 121 returns to its adjusted position. Thus, when braking the vehicle again after the first mode has been executed, braking is achieved by compensating for the wear of the brake pad 10 through the relative position of the piston 110 relative to the main shaft 121 or the nut 125, thereby enabling stable braking of the vehicle.

[0071] The following describes the operation of the electromechanical brake 100 according to this embodiment in performing the second mode to reduce the resistance phenomenon that the piston 110 cannot quickly return to its original position after the vehicle braking operation.

[0072] When the vehicle's brakes are released, if the force of contact or engagement between the brake disc and the brake pad 10 measured by the sensing unit 140 is greater than a preset normal range value, the electronic control unit can determine that there is resistance that prevents the piston 110 from returning to its original position, and thus enter the second mode.

[0073] Figure 6 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.

[0074] Reference Figure 6To enter the second mode, the electronic control unit controls the operation of the actuator to rotate the main shaft 121 in a second direction. At this time, the electronic control unit causes the main shaft 121 to rotate in an additional second direction, exceeding the preset rotation amount corresponding to the transition from the normal braking state to the brake release state. The torsion spring 137 expands further due to this additional second-direction rotation of the main shaft 121 compared to the normal vehicle brake release state. At this point, the elastic restoring force of the torsion spring 137 is greater than the threaded engagement force between the adjusting screw 131 and the piston 110. When the torsion spring 137 is compressed to return to its original shape, a second-direction rotation is generated between the nut 125 and the adjusting screw 131. This causes the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 to shift backward, separating the piston 110 from the pad, thereby reducing resistance.

[0075] Hereinafter, an electromechanical brake according to a modified embodiment of the present invention will be described.

[0076] In the following description of the electromechanical brake according to a modified embodiment of the present invention, the contents are the same as those of the electromechanical brake 100 according to this embodiment described above, except where further description is given by additional reference numerals. To avoid repetition, the description of the electromechanical brake will be omitted.

[0077] Figure 7 This is an enlarged side cross-sectional view showing the main part of the electromechanical brake 100 according to a modified embodiment of the present invention, with reference to... Figure 7 It can be equipped with a connecting cover 210 that connects the adjusting screw 131 and the nut 125.

[0078] The cap 210 is configured to cover the front opening of the nut 125, with its inner circumference fixed and supported on the nut 125, and its outer circumference fixed and supported on the inner circumference of the adjusting screw 131. This allows the nut 125 and the adjusting screw 131 to engage with each other. The cap 210 synchronizes the rotational and linear movements of the nut 125 and the adjusting screw 131. Furthermore, the adjusting screw 131 and the piston 110 are threaded together and move as a single unit. Therefore, when the vehicle's brakes are released, as the nut 125 returns to its original position, the adjusting screw 131 and the piston 110 can also smoothly return to their original positions, thus quickly preparing for subsequent vehicle braking operations.

Claims

1. An electromechanical brake, comprising: The piston is movable back and forth to press the brake pad; The power conversion unit receives driving force from the actuator to convert the rotational motion into linear motion and then provides it 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 power conversion unit includes: The main shaft receives driving force from the actuator and rotates; and A nut is connected to the main shaft, and moves forward inside the piston by rotation of the main shaft in a first direction, thereby moving the piston forward; and moves backward inside the piston by rotation of the main shaft in a second direction, thereby moving the piston backward. The position adjustment unit includes: Adjust the screw, positioned outside the nut to prevent relative rotation, and rotate with the nut; A first thread is formed on the outer circumferential surface of the adjusting screw; A second thread is formed on the inner circumferential surface of the piston and engages with the first thread; and An adjuster is disposed between the main shaft and the nut, and compresses or expands back to its original shape when the rotation of the main shaft exceeds a preset rotation amount, so that the nut and the adjusting screw rotate in a first direction or a second direction, thereby causing the relative position of the piston to move forward or backward.

2. The electromechanical brake according to claim 1, wherein, The adjuster includes: A flange is formed radially extending from the outer circumferential surface of the spindle; and The torsion spring is supported at one end by the nut and at the other end by the flange.

3. The electromechanical brake according to claim 2, wherein, From the moment the vehicle's brakes are released to the moment the vehicle is braked, the torsion spring is compressed according to the amount of rotation of the main shaft in the first direction. The elastic restoring force of the torsion spring according to the amount of rotation in the first direction is less than the threaded engagement force between the adjusting screw and the piston.

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

5. The electromechanical brake according to claim 2, wherein, The position adjustment unit further includes: The cover is then used to engage the adjusting screw and the nut.

6. The electromechanical brake according to claim 2, further comprising: The electronic control unit controls the operation of the actuator; as well as The sensing unit measures the bonding force between the brake disc and the brake pad, which rotate together with the wheel.

7. A method for operating an electromechanical brake, which is the method for operating an electromechanical brake according to claim 6. When the vehicle is braking, if the force between the brake disc and the brake pad measured by the sensing unit is less than a preset value, the electronic control unit determines that the brake pad is worn and enters a first mode that moves the relative position of the piston forward.

8. The method of operating the electromechanical brake according to claim 7, wherein, When the vehicle's brakes are released, if the force between the brake disc and the brake pad measured by the sensing unit is greater than a preset value, the electronic control unit determines that there is resistance and enters a second mode that moves the relative position of the piston backward.

9. The method of operating the electromechanical brake according to claim 7, wherein, In the first mode, the operation of the actuator is controlled to rotate the main shaft in a first direction from the vehicle's brake release state to the vehicle's braking state, thereby compressing the torsion spring and causing the main shaft to generate an additional rotation in the first direction exceeding the preset rotation amount. The elastic restoring force of the torsion spring guides the rotation of the nut and the adjusting screw in a first direction, so that the relative position of the piston with respect to the nut is moved forward by the rotation of the adjusting screw in the first direction.

10. The method of operating the electromechanical brake according to claim 8, wherein, In the second mode, the actuator is controlled to rotate the main shaft in a second direction from the vehicle's braking state to the vehicle's brake release state, thereby inflating the torsion spring and causing the main shaft to rotate an additional amount in the second direction beyond the preset rotation. The elastic restoring force of the torsion spring guides the rotation of the nut and the adjusting screw in a second direction, thereby causing the relative position of the piston with respect to the nut to shift backward through the rotation of the adjusting screw in the second direction.

Images