Electromechanical brake system and method of controlling the same

Abstract

Electromechanical brake system and control method thereof. An electromechanical brake system of one embodiment includes an actuator of an electromechanical brake that operates by a motor, a motor drive portion that drives the motor, and a control portion that is electrically connected to the motor drive portion, calculates a first rotation angle of a spindle when the electromechanical brake is in an apply mode, calculates a second rotation angle of the spindle when the electromechanical brake is in a release mode, and controls a notification device to notify a wear state of a brake pad when there is a difference between the calculated first rotation angle and the calculated second rotation angle.

Description

Technical Field

[0001] This invention relates to an electromechanical braking system and its control method that can notify the driver of the wear status of brake pads in real time. Background Technology

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

[0003] In the past, braking systems primarily relied on mechanically connected boosters to supply the hydraulic pressure required for braking to the wheel cylinders when the driver pressed the brake pedal. However, as a next-generation braking system, electromechanical braking systems have recently been developed that receive the driver's braking intention via electrical signals and drive an electric motor to provide braking force to the vehicle.

[0004] Such an electromechanical braking system converts the rotational force of the motor into linear motion through a motor and a reducer, thereby providing clamping force to the brake disc and performing vehicle service braking and parking braking.

[0005] However, in the case of conventional electromechanical braking systems, the brake pads gradually wear down due to repeated braking and releasing actions.

[0006] Therefore, in the case of conventional electromechanical braking systems, it is impossible to determine the wear condition of the brake pads. Even if the brake pads are worn, this is not recognized, thus posing a risk of accident when braking. Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] One aspect provides an electromechanical braking system and its control method that can notify the driver of the wear status of brake pads in real time.

[0009] Methods for solving problems

[0010] According to one aspect of the disclosed invention, an electromechanical braking system is provided, comprising an actuator for an electromechanical brake operated by a motor. The electromechanical braking system includes: a motor drive unit that drives the motor; and a control unit electrically connected to the motor drive unit. When the electromechanical brake is in an apply mode, the control unit calculates a first rotation angle of a spindle rotated by the motor drive. When the electromechanical brake is in a release mode, the control unit calculates a second rotation angle of the spindle. When there is a difference between the calculated first rotation angle and the calculated second rotation angle, the control unit controls a notification device to notify the brake pads of their wear condition.

[0011] The control unit receives first rotation angle information of the motor obtained by the motor position sensor during the braking operation mode, and calculates the first rotation angle of the spindle based on the received first rotation angle information of the motor. The control unit also receives second rotation angle information of the motor obtained by the motor position sensor during the braking operation release mode, and calculates the second rotation angle of the spindle based on the received second rotation angle information of the motor.

[0012] The aforementioned braking operation modes include at least one of a mode for performing braking operations of the aforementioned electromechanical brake and a mode for performing compensatory braking operations of the aforementioned electromechanical brake for brake pad wear.

[0013] The aforementioned brake release mode includes at least one of the following modes: a mode for performing brake release action of the aforementioned electromechanical brake and a mode for performing compensatory brake release action of the aforementioned electromechanical brake in response to drag phenomenon.

[0014] The aforementioned control unit controls the aforementioned notification device to notify the wear condition of the brake pads related to the corresponding electromechanical brakes in the front and rear wheel electromechanical brakes.

[0015] The aforementioned notification device is the center console located between the driver's seat and the passenger seat.

[0016] When there is a difference between the first rotation angle calculated above and the second rotation angle calculated above, the control unit further calculates the adjustment stroke value of the piston corresponding to the difference value of the rotation angle. In order to advance the relative position of the piston in accordance with the calculated adjustment stroke value of the piston, the control unit further controls the motor drive unit to make the motor rotate.

[0017] According to another aspect of the disclosed invention, a control method for an electromechanical braking system is provided. The electromechanical braking system includes an actuator for an electromechanical brake that is operated by a motor. The control method for the electromechanical braking system includes the following steps: when the electromechanical brake is in a braking action mode, calculating a first rotation angle of a spindle that rotates under the drive of the motor; when the electromechanical brake is in a braking action release mode, calculating a second rotation angle of the spindle; and when there is a difference between the calculated first rotation angle and the calculated second rotation angle, notifying the wear condition of the brake pads.

[0018] In the step of calculating the first rotation angle of the spindle, the first rotation angle information of the motor obtained by the motor position sensor during the braking operation mode is received, and the first rotation angle of the spindle is calculated based on the received first rotation angle information of the motor.

[0019] In the step of calculating the second rotation angle of the spindle, the second rotation angle information of the motor obtained by the motor position sensor during the braking action release mode is received, and the second rotation angle of the spindle is calculated based on the received second rotation angle information of the motor.

[0020] In the step of notifying the wear condition of the aforementioned brake pads, the wear condition of the brake pads related to the corresponding electromechanical brakes in the front and rear wheel electromechanical brakes is notified.

[0021] It also includes the following steps: when there is a difference between the first rotation angle calculated above and the second rotation angle calculated above, the adjustment stroke value of the piston corresponding to the difference value of the rotation angle is further calculated, and the motor is rotated so that the relative position of the piston advances in accordance with the adjustment stroke value of the piston calculated above.

[0022] Invention Effects

[0023] According to one aspect of the disclosed invention, it is possible to notify the driver of the wear status of the brake pads in real time. Attached Figure Description

[0024] Figure 1 This describes the structure of an electromechanical brake included in an electromechanical braking system according to one embodiment.

[0025] Figure 2 The figure is a cross-sectional view of the main components of an electromechanical brake included in an electromechanical braking system of one embodiment.

[0026] Figure 3 The figure illustrates the main components of an electromechanical brake included in an electromechanical braking system of one embodiment.

[0027] Figure 4 This refers to the braking action of an electromechanical brake included in an electromechanical braking system in one embodiment.

[0028] Figure 5 This indicates the brake release action of the electromechanical brake in an electromechanical braking system included in one embodiment.

[0029] Figure 6 This refers to the compensatory braking action of the electromechanical brake in an electromechanical braking system included in one embodiment in response to brake pad wear.

[0030] Figure 7 This refers to the compensatory brake release action of the electromechanical brake in an electromechanical braking system included in one embodiment, in response to drag phenomenon.

[0031] Figure 8 This illustrates the structure of an electromechanical braking system according to one embodiment.

[0032] Figure 9 This refers to the case where the piston adjustment stroke value is calculated based on the difference in rotation angle with the main shaft in an electromechanical braking system according to one embodiment.

[0033] Figure 10 This describes the process of calculating the required piston adjustment stroke value based on the difference in the rotation angle of the spindle in an electromechanical braking system according to one embodiment.

[0034] Figure 11 This describes a control method for an electromechanical braking system according to one embodiment.

[0035] Figure 12 This describes a case where an instrument cluster is installed in a vehicle using an electromechanical braking system according to one embodiment.

[0036] Figure 13 This indicates that the wear condition of the brake pads of the left-side electromechanical brake in a vehicle using an electromechanical braking system according to one embodiment is displayed via a display panel in the instrument cluster. Detailed Implementation

[0037] Throughout this specification, the same symbols denote the same constituent elements. Not all elements of the embodiments are described in this specification; general content within the technical field to which the disclosed invention pertains or content repeated between embodiments is omitted. Terms such as 'part, module, component, block' as used in the specification can be implemented in software or hardware. According to embodiments, multiple 'parts, modules, components, blocks' may be implemented by a single constituent element, or a 'part, module, component, block' may include multiple constituent elements.

[0038] Throughout the instruction manual, when referring to a part as being "connected" to other parts, this includes not only direct connections but also indirect connections, including connections via wireless communication networks.

[0039] Furthermore, when referring to a part as "including" a certain element, it does not exclude other elements unless otherwise stated, but may include other elements.

[0040] Throughout the instruction manual, when referring to a component as being "on" other components, this includes not only cases where a component is connected to other components, but also cases where there is another component between the two components.

[0041] The terms "first" and "second" are used to distinguish one element from others, and these terms do not limit the elements. Unless explicitly excluded in the text, the singular includes the plural.

[0042] The identification numbers are used for illustrative purposes only and do not indicate the order of the steps. If no specific order is specified in the text, the steps may be performed in a different order than that described.

[0043] Figure 1 This describes the structure of an electromechanical brake included in an electromechanical braking system according to one embodiment.

[0044] Reference Figure 1 The electromechanical brake 100 of this embodiment includes: a carrier (not shown) having a pair of pads 11, 12 for pressurizing a brake disc (not shown) that rotates together with the wheels of the vehicle; a caliper housing 20 slidably disposed on the carrier to actuate the pair of pads 11, 12; a piston 110 disposed inside the caliper housing 20 in a forward-moving manner; an actuator 160 that generates and provides a driving force to move the piston 110; and a power conversion unit 120 that receives power from the actuator 160. The provided rotational driving force is converted into linear motion and transmitted to the piston 110 to achieve axial forward movement of the piston 110; a position adjustment unit 130 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; and a sensing unit 140 measures the adhesion force between the brake disc (not shown) and the brake pad 10 or the clamping force of the brake pad 10. A pair of pads 11 and 12 have brake pads 10 attached to their inner surfaces. The pair of pads 11 and 12 consist of an inner pad 11 that is configured to contact the piston 110 and an outer pad 12 that is configured to contact the claw portion 22 of the caliper housing 20 (described later) and are slidably disposed on the carrier.

[0045] The caliper housing 20 includes a claw portion 22 for actuating the outer pad 12 and a cylinder portion 21 with a piston 110, and is slidably fastened to a carrier. When the vehicle is braked, the caliper housing 20 slides from the carrier and moves to the brake disc (not shown) side by the reaction force generated by the movement of the piston 110, thereby pressurizing the brake disc (not shown) by the outer pad 12 approaching the brake disc (not shown) side via the claw portion 22.

[0046] Figure 2 The figure is a cross-sectional view of the main components of an electromechanical brake included in an electromechanical braking system of one embodiment. Figure 3 The figure illustrates the main components of an electromechanical brake included in an electromechanical braking system of one embodiment.

[0047] Reference Figures 1 to 3 The piston 110 is a cup-shaped cylinder with its rear side open, allowing it to slide inside the cylinder body 21. Furthermore, the piston 110 receives power from the actuator 160 and power conversion unit 120 (described later) to press the inner pad 11 against the brake disc (not shown). 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). The power conversion unit 120 includes: a main shaft 121 that receives driving force from the actuator 160 and rotates; a nut 125 disposed inside the piston 110, threadedly connected to the main shaft 121 and rotating in a first direction with the main shaft 121 to move forward with the piston 110 or rotating in a second direction with the main shaft 121 to move backward with the piston 110; and a plurality of balls 129 located between the main shaft 121 and the nut 125. Such a power conversion unit 120 is composed of a ball screw type conversion device that converts the rotary motion of the main shaft 121 into linear motion.

[0048] 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.

[0049] 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 the actuator 160 and receiving driving force; and a central portion 121b disposed between the first end 121a and the second end 121c for fixing the flange 136 described later. The first end 121a of the spindle 121 is inserted into the inside of the nut 125, and the second end 121c is provided with a bearing 150 for facilitating smooth rotation of the flange 136 described later, and a sensing portion 140 for sensing the load applied to the spindle 121 and measuring the fastening force between the brake disc (not shown) and the brake pad 10.

[0050] The nut 125 is formed in a hollow cylindrical shape to be inserted into the first end 121a of the main shaft 121. An internal thread 126 is formed on its inner circumferential surface, engaging with the external thread 122 of the main shaft 121 via a ball 129. Furthermore, an adjusting screw 131, described later, surrounds at least a portion of the outer circumferential surface of the nut 125 and is formed on the outside of the nut 125. At least a portion of the outer circumferential surface of the nut 125 has a rotation-preventing surface 125a, which is planar, to prevent relative rotation with the adjusting screw 131. Ball screw type power conversion devices are widely used and well-known technologies; therefore, detailed descriptions are omitted.

[0051] The actuator 160 comprises a reduction gear 162 including a motor 161 and multiple reduction gears, and receives power from a power supply unit located in the vehicle to generate driving force. The actuator 160 is connected to the second end 121c of the main shaft 121 to transmit the generated driving force as rotational motion of the main shaft 121. The actuator 160 is located on the outside of the caliper housing 20. The reduction gear 162 can be a device with various structures such as a planetary gear assembly or a worm gear structure, which reduces the power of the motor 161 and provides it to the main shaft 121. The motor 161 rotates the main shaft 121, causing the nut 125 to move forward and backward, thereby pressurizing or depressurizing the piston 110. The reduction gear 162 is located between the output shaft of the motor 161 and the main shaft 121.

[0052] The position adjustment unit 130 adjusts the relative position of the piston 110 relative to the power conversion unit 120, thereby advancing the relative position of the piston 110 to compensate for the wear of the brake pad 10, or retracting the relative position of the piston 110 to reduce drag.

[0053] The position adjustment part 130 includes: an adjustment screw 131, which is located on the outside of the nut 125 and rotates together with the nut 125; a first thread 132, which is formed on the outer peripheral surface of the adjustment screw 131; a second thread 133, which is formed on the inner peripheral surface of the piston 110 and engages with the first thread 132; and an adjuster 135, which is located between the main shaft 121 and the nut 125 and compresses or expands according to the amount of rotation of the main shaft 121, thereby causing the nut 125 and the adjustment screw 131 to rotate in a first direction to advance the relative position of the piston 110, or to rotate the nut 125 and the adjustment screw 131 in the opposite direction of the first direction, i.e., a second direction, to retract the relative position of the piston 110.

[0054] 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, which refers to 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, being the opposite direction to the first direction, is the same as the second direction of rotation of the main shaft 121 described above, which refers to the direction of rotation in which the piston 110 is retracted by rotating the adjusting screw 131.

[0055] The adjusting screw 131 is provided to surround the front side portion of the nut 125, and is constructed by forming a first thread 132 on its outer peripheral surface. The adjusting screw 131 rotates together with the nut 125, and at least a portion of the inner peripheral surface that contacts the nut 125 is formed as a plane to prevent relative rotation. When the nut 125 is rotated by the adjuster 135 (described later), the adjusting screw 131 rotates together with the nut 125 and transmits the rotational force of the nut 125 to the piston 110 side. The adjusting screw 131 is formed between the nut 125 and the piston 110, thereby absorbing the load generated when the nut 125 and the piston 110 come into contact, thereby preventing deformation and wear of components such as the nut 125 and the piston 110 under heavy loads.

[0056] A first thread 132 is formed on the outer peripheral surface of the adjusting screw 131, and a second thread 133 is formed on the inner peripheral surface of the piston 110. The first thread 132 and the second thread 133 mesh with each other. Thus, the adjusting screw 131 and the piston 110, which rotate and move linearly together with the nut 125, are threaded together. As a result, the nut 125, the adjusting screw 131, and the piston 110 move linearly together. Therefore, when braking a normal vehicle, the nut 125, the adjusting screw 131, and the piston 110 move forward together, or when the vehicle brakes are released, the nut 125, the adjusting screw 131, and the piston 110 move backward together. At the same time, as the piston 110 and the adjusting screw 131 can rotate relative to each other, the piston 110 moves forward relative to the nut 125 or the main shaft 121 by rotating the nut 125 and the adjusting screw 131 in the first direction, and the nut 125 and the adjusting screw 131 rotate in the opposite direction, i.e., the second direction, so that the piston 110 moves backward relative to the nut 125 or the main shaft 121.

[0057] The adjuster 135 rotates the nut 125 and the adjusting screw 131 to advance or retract the relative position of the piston 110 with respect to the nut 125 or the spindle 121. The adjuster 135 includes: a flange 136 fixed to the central portion 121b of the spindle 121 and extended radially; and a torsion spring 137 disposed between the nut 125 and the flange 136 to elastically support the nut 125 relative to the flange 136, which compresses or expands back to its original shape when the spindle 121 or the flange 136 exceeds a predetermined rotation angle, thereby guiding the nut 125 and the adjusting screw to rotate in a first direction or a second direction.

[0058] The flange 136 is formed by extending radially from the central portion 121b of the main shaft 121 and is fixed to the main shaft 121 and rotates integrally with the main shaft 121. A bearing 150 may be provided on the back side of the flange 136 to enable smooth rotation of the flange 136 and prevent wear between the flange 136 and surrounding components.

[0059] One end of the torsion spring 137 is inserted into and fixed to the outer circumferential surface of the nut 125, and the other end is inserted into and fixed to the flange 136. The torsion spring 137 is kept in a compressed or expanded state within a predetermined rotation angle, such as the rotation angle of the main shaft 121 between the vehicle's brake release state and braking state. When the predetermined rotation angle is exceeded, it is compressed or expanded to return to its original state, thereby guiding the nut 125 and the adjusting screw 131 to rotate in a first direction or a second direction.

[0060] Specifically, in the pre-driving state or when the vehicle is in a brake-released state, when switching to the braking state, the elastic restoring force generated by the first-direction rotation angle of the main shaft 121 is less than the threaded fastening 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 remains compressed, keeping the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 fixed.

[0061] When the first-direction rotation angle of the main shaft 121 used for braking the vehicle exceeds a predetermined rotation angle in order to perform a compensating braking action for wear of the brake pads 10, the electromechanical brake 100 causes the elastic restoring force of the torsion spring 137 to be greater than the threaded fastening force between the adjusting screw 131 and the piston 110. This causes the torsion spring 137 to expand and return to its original shape. The expansion of the torsion spring 137 generates first-direction rotation of the nut 125 and the adjusting screw 131. Therefore, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 advances.

[0062] When the second-direction rotation angle of the main shaft 121 used for releasing the vehicle's brakes exceeds a predetermined rotation angle in order to perform a compensatory brake release action against dragging, the electromechanical brake 100 causes the elastic restoring force of the torsion spring 137 to exceed the threaded fastening force between the adjusting screw 131 and the piston 110. This compresses the torsion spring 137, restoring it to its original shape. The compression of the torsion spring 137 causes the nut 125 and the adjusting screw 131 to rotate in the second direction. Therefore, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 retracts.

[0063] Force sensor 141 measures the contact force or clamping force between the brake disc (not shown) and the brake pad 10. Force sensor 141 senses the load on the spindle 121 or actuator 160 to measure the clamping force between the brake disc (not shown) and the brake pad 10. Force sensor 141 transmits the clamping force information between the brake disc (not shown) and the brake pad 10 to the control unit 220.

[0064] Motor position sensor 142 measures the rotation angle of motor 161. Motor position sensor 142 measures a first rotation angle of motor 161 in braking operation mode and a second rotation angle of motor 161 in braking release mode. The braking operation mode includes at least one of a mode for performing braking action of electromechanical brake 100 and a mode for performing compensatory braking action of electromechanical brake 100 to compensate for brake pad wear. The braking release mode includes at least one of a mode for performing brake release action of electromechanical brake 100 and a mode for performing compensatory brake release action of electromechanical brake 100 to compensate for drag. Motor position sensor 142 transmits the first rotation angle information and the second rotation angle information of motor 161 to control unit 220.

[0065] Figure 4 This refers to the braking action of an electromechanical brake included in an electromechanical braking system in one embodiment.

[0066] Reference Figure 4 The electromechanical brake 100 uses the actuator 160 to rotate the main shaft 121 in the first direction, thereby causing the nut 125 to move forward and pressurize the piston 110. The piston 110, which is pressurized by the movement of the nut 125, pressurizes the inner pad 11 and causes the brake pad 10 to press tightly against the brake disc (not shown), thereby performing a braking action that generates clamping force.

[0067] At this time, the main shaft 121 rotates in the first direction, compressing the torsion spring 137. However, the elastic restoring force of the torsion spring 137 generated by the predetermined rotation angle in the first direction from the vehicle's brake release state to the vehicle's braking state is less than the threaded fastening force between the adjusting screw 131 and the piston 110. Therefore, during normal braking operations, the nut 125 and the adjusting screw 131 do not rotate. Thus, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 can be kept fixed.

[0068] Figure 5 This indicates the brake release action of the electromechanical brake in an electromechanical braking system included in one embodiment.

[0069] Reference Figure 5 The electromechanical brake 100 uses the actuator 160 to rotate the main shaft 121 in the second direction, thereby causing the nut 125 that pressurizes the piston 110 to move backward. The backward movement of the nut 125 releases the pressure on the piston 110. By releasing the pressure on the piston 110, the brake pad 10 is separated from the brake disc (not shown), thereby performing the brake release action of releasing the clamping force generated.

[0070] At this time, the second direction rotation angle of the main shaft 121 corresponds to the first direction rotation angle of the main shaft 121 in normal braking action, thereby the torsion spring 137 returns to its original shape according to the second direction rotation of the main shaft 121.

[0071] Figure 6 This refers to the compensatory braking action of the electromechanical brake in an electromechanical braking system included in one embodiment in response to brake pad wear.

[0072] Reference Figure 6 The electromechanical brake 100 uses the actuator 160 to rotate the main shaft 121 in the first direction by more than a predetermined rotation angle, thereby generating the rotation of the nut 125 and the adjusting screw 131 to further pressurize the piston 110. The piston 110, which is further pressurized by the rotation of the nut 125 and the adjusting screw 131, further pressurizes the inner pad 11, causing the brake pad 10 to be further pressed against the brake disc (not shown), thereby performing a compensating braking action for the wear of the brake pad 10.

[0073] At this time, the main shaft 121 rotates additionally in the first direction, causing the torsion spring 137 to be compressed more than in a normal braking action. This results in the elastic restoring force of the torsion spring 137 being greater than the threaded fastening force between the adjusting screw 131 and the piston 110. Consequently, the torsion spring 137 expands to return to its original shape, causing the nut 125 and the adjusting screw 131 to rotate in the first direction. Therefore, the relative position of the piston 110 with respect to the nut 125 or the main shaft 121 advances, compensating for the wear of the brake pad 10.

[0074] Figure 7 This refers to the compensatory brake release action of the electromechanical brake in an electromechanical braking system included in one embodiment, in response to drag phenomenon.

[0075] Reference Figure 7 The electromechanical brake 100 uses the actuator 160 to rotate the main shaft 121 beyond a predetermined rotation angle in the second direction, thereby generating the rotation of the nut 125 and the adjusting screw 131 to further release the pressure on the piston 110. The piston 110, which is further released from pressure by the rotation of the nut 125 and the adjusting screw 131, is further separated from the inner pad 11, thereby performing a compensating brake release action against the drag phenomenon of the brake pad 10.

[0076] At this point, the spindle 121 is rotated in the second direction, causing the torsion spring 137 to expand more than in a normal brake release action. This results in the elastic restoring force of the torsion spring 137 being greater than the threaded fastening force between the adjusting screw 131 and the piston 110. Consequently, the torsion spring 137 compresses to return to its original shape, causing the nut 125 and the adjusting screw 131 to rotate in the second direction. Therefore, the relative position of the piston 110 with respect to the nut 125 or the spindle 121 retracts, thereby reducing the drag of the piston 110 from returning to its original position.

[0077] An electromechanical braking system of one embodiment calculates a first rotation angle and a second rotation angle of the spindle based on a first rotation angle information and a second rotation angle information of the motor obtained by a motor position sensor. When there is a difference between the calculated first rotation angle and the calculated second rotation angle, the system notifies the driver in real time of the wear condition of the brake pads and guides the replacement of the brake pads.

[0078] Figure 8 This illustrates the structure of an electromechanical braking system according to one embodiment.

[0079] Reference Figure 8 The electromechanical braking system 200 includes a motor 161, a motor drive unit 210, and a control unit 220.

[0080] The control unit 220 can receive brake pedal information via the brake pedal position sensor, and can also receive brake pedal information from other systems that perform in-vehicle network communication, i.e., CAN (Controller Area Network). For example, the control unit 220 receives brake pedal information from the ABS system or TCS system. Brake pedal information is the operation signal of the brake pedal pressed by the driver. The control unit 220 receives clamping force information between the brake disc (not shown) and the brake pad 10 from the force sensor 141.

[0081] The control unit 220 drives the motor 161 based on the braking signal generated by the driver pressing the brake pedal. The control unit 220 executes either the brake application mode or the brake release mode based on the braking signal generated by the driver pressing the brake pedal.

[0082] The motor drive unit 210 drives the motor 161. The motor drive unit 210 drives the motor 161 in a first direction or a second direction. When the motor drive unit 210 drives the motor 161 in the first direction, the electromechanical brake 100 performs a braking action; when the motor 161 is driven in the second direction, the electromechanical brake 100 performs a brake release action. The motor drive unit 210 generates a motor current that drives the motor 161 in the first direction or the second direction and applies it to the motor 161. For example, the motor drive unit 210 includes an H-bridge circuit composed of multiple power switching elements to drive the motor 161 in the first direction or the second direction.

[0083] The control unit 220 includes a processor 221 and a memory 222.

[0084] The processor 221 calculates a first rotation angle of the spindle 121 during the braking operation mode of the electromechanical brake 100. The processor 221 receives first rotation angle information of the motor 161 obtained via the motor position sensor 142 during the braking operation mode, and calculates the first rotation angle of the spindle 121 based on the received first rotation angle information of the motor 161. When the rotation of the motor 161 is in a first direction, the processor 221 determines that it is in braking operation mode, and calculates the first rotation angle of the spindle 121 based on the received first rotation angle information of the motor 161. The braking operation mode includes at least one of a mode for performing braking action of the electromechanical brake 100 and a mode for performing compensatory braking action of the electromechanical brake 100 for brake pad wear.

[0085] When the electromechanical brake 100 is in brake release mode, the processor 221 calculates the second rotation angle of the spindle 121. The processor 221 receives the second rotation angle information of the motor 161 obtained by the motor position sensor 142 during brake release mode, and calculates the second rotation angle of the spindle 121 based on the received second rotation angle information of the motor 161. When the rotation of the motor 161 is in the second direction, the processor 221 determines that it is in brake release mode, and calculates the second rotation angle of the spindle 121 based on the received second rotation angle information of the motor 161. The brake release mode includes at least one of a mode for performing brake release action of the electromechanical brake 100 and a mode for performing compensatory brake release action of the electromechanical brake 100 against drag.

[0086] When there is a difference between the calculated first rotation angle and the calculated second rotation angle of the main shaft 121, the processor 221 controls the notification device 300 to notify the wear condition of the brake pads 10. The notification device 300 notifies the wear condition of the brake pads 10 associated with the corresponding electromechanical brakes in the front and rear wheel electromechanical brakes. For example, the notification device 300 notifies the wear condition of the brake pads 10 associated with the left front wheel electromechanical brake, the right front wheel electromechanical brake, the left rear wheel electromechanical brake, and the right rear wheel electromechanical brake.

[0087] When there is a difference between the calculated first rotation angle of the spindle 121 and the calculated second rotation angle of the spindle 121, the processor 221 further calculates the adjustment stroke value of the piston 110 corresponding to the difference value of the rotation angle.

[0088] Figure 9 This indicates the case where the piston's adjustment stroke value is calculated based on the difference in rotation angle between the piston and the main shaft in an electromechanical braking system of one embodiment.

[0089] Reference Figure 9 When there is a difference between the first rotation angle A of the main shaft 121 in the calculated braking action mode and the second rotation angle B of the main shaft 121 in the calculated braking action release mode, the processor 221 can calculate the piston adjustment stroke value D corresponding to the difference value C of the rotation angle.

[0090] As an experimental example, the electromechanical brake 100 performs braking and brake release actions in primary, secondary, tertiary, and quaternary braking states respectively, based on the driver's operation of pressing the brake pedal. The processor 221 calculates the difference value C of the rotation angle related to the primary, secondary, tertiary, and quaternary braking states, and the piston adjustment stroke value D corresponding to the difference value C. For example, if the processor 221 determines that the difference value C of the rotation angle related to the secondary and quaternary braking states is "5" and "7", it calculates the piston adjustment stroke value D as "0.11" and "0.16" respectively, corresponding to "5" and "7". At this time, when performing braking and brake release actions in the secondary and quaternary braking states, the processor 221 determines that the brake pads 10 are in a worn state.

[0091] Figure 10 This describes the process of calculating the required piston adjustment stroke value based on the difference in the rotation angle of the spindle in an electromechanical braking system according to one embodiment.

[0092] Reference Figure 10When there is a difference between the first rotation angle of the main shaft 121 during the calculated braking action mode and the second rotation angle of the main shaft 121 during the calculated braking action release mode, the processor 221 calculates the piston adjustment stroke value required based on the difference in the rotation angle of the main shaft. At this time, TS1 is the piston adjustment stroke value required in the braking action release direction based on the difference in rotation angle. When the difference in rotation angle is "5", the piston adjustment stroke value in the braking action release direction is output as "0.11", and when the difference in rotation angle is "7", the piston adjustment stroke value in the braking action release direction is output as "0.16". On the other hand, S1 is the piston stroke value in the braking action direction, S2 is the adjuster stroke value, and S3 is the nut stroke value.

[0093] The processor 221 further controls the motor drive unit 210 to rotate the motor 161, causing the piston 110 to advance in a manner corresponding to the calculated adjustment stroke value of the piston 110. For example, the processor 221 controls the motor drive unit 210 in a manner corresponding to the piston's adjustment stroke value D, namely "0.11" and "0.16".

[0094] The processor 221 includes a digital signal processor that processes first rotation angle information and second rotation angle information of the motor 161, and a microcontroller unit (MCU) that generates a notification signal for informing the brake pad 10 of its wear status.

[0095] The memory 222 stores the program and / or data of the processor 221 for processing the first rotation angle information and the second rotation angle information of the motor 161, and the program and / or data of the processor 221 for generating a notification signal that notifies the wear status of the brake pad 10.

[0096] The memory 222 temporarily stores the first rotation angle information and the second rotation angle information of the motor 161, and temporarily stores the processing result of the processor 221 of the first rotation angle information and the second rotation angle information of the motor 161.

[0097] The memory 222 may include not only volatile memories such as S-RAM and D-RAM, but also non-volatile memories such as flash memory, read-only memory (ROM), and erasable programmable read-only memory (EPROM).

[0098] Figure 11 This describes a control method for an electromechanical braking system according to one embodiment.

[0099] Reference Figure 11 When the control unit 220 executes the braking action mode of the electromechanical brake 100 based on the operation of the brake pedal pressed by the driver, it receives first rotation angle information (1110) of the motor 161 obtained by the motor position sensor 142. Based on the received first rotation angle information of the motor 161, the control unit 220 calculates the first rotation angle (1120) of the spindle 121. When the motor 161 rotates in the first direction, the control unit 220 determines that a braking action mode has been entered. The braking action mode includes at least one of a mode for executing the braking action of the electromechanical brake 100 and a mode for executing a compensatory braking action of the electromechanical brake 100 for brake pad wear.

[0100] When the electromechanical brake 100 is in brake release mode, the control unit 220 receives second rotation angle information (1130) of the motor 161 obtained by the motor position sensor 142. Based on the received second rotation angle information of the motor 161, the control unit 220 calculates the second rotation angle (1140) of the spindle 121. When the motor 161 rotates in the second direction, the control unit 220 determines that it is in brake release mode. The brake release mode includes at least one of a mode for performing brake release action of the electromechanical brake 100 and a mode for performing compensatory brake release action of the electromechanical brake 100 against drag.

[0101] The control unit 220 determines whether there is a difference between the calculated first rotation angle of the spindle 121 and the calculated second rotation angle of the spindle 121 (1150). When there is a difference between the calculated first rotation angle of the spindle 121 and the calculated second rotation angle of the spindle 121, the control unit 220 determines that the brake pad 10 is worn.

[0102] When there is a difference between the calculated first rotation angle of the spindle 121 and the calculated second rotation angle of the spindle 121, the control unit 220 controls the notification device 300 to notify the brake pad 10 of its wear condition (1160).

[0103] Figure 12 This describes a case where an instrument cluster is installed in a vehicle using an electromechanical braking system according to one embodiment.

[0104] Reference Figure 12The notification device 300 may be a center console located on the dashboard between the driver's and passenger's seats within the vehicle 1, and may include a display panel 301 for an AVN (Audio / Video / Navigation) device that displays the wear status of the brake pads to the driver or outputs voice and image information. The notification device 300 notifies the driver of the wear status of the brake pads related to the corresponding electromechanical brakes in the front and rear wheel electromechanical brakes. The notification device 300 is not limited to the illustrated configuration; it may display the wear status of the brake pads via an instrument panel or a separate terminal, or via a HUD (Head-Up Display) device located on the driver's window.

[0105] Figure 13 The wear condition of the brake pads of the left-side electromechanical brake is displayed via a display panel in the instrument cluster of a vehicle using an electromechanical braking system according to one embodiment.

[0106] Reference Figure 13 The notification device 300 notifies the wear condition of the brake pads of the left front wheel electromechanical brake via the display panel 301. Not limited to the illustrated case, the notification device 300 can also notify the wear condition of brake pads related to the right front wheel electromechanical brake, the left rear wheel electromechanical brake, and the right rear wheel electromechanical brake.

[0107] On the other hand, if there is no difference between the calculated first rotation angle of the spindle 121 and the calculated second rotation angle of the spindle 121 in the judgment result of the operation mode 1150, the notification device 300 is not controlled so as not to notify the wear state of the brake pad 10.

[0108] When there is a difference between the calculated first rotation angle and the calculated second rotation angle of the main shaft 121, the control unit 220 further calculates the adjustment stroke value (1170) of the piston 110 corresponding to the difference value of the rotation angle. The control unit 220 calculates the difference value C of the rotation angle related to the first braking state, the second braking state, the third braking state, and the fourth braking state, and the adjustment stroke value D of the piston corresponding to the difference value C of the rotation angle. For example, if the control unit 220 determines that the difference value C of the rotation angle related to the second braking state and the fourth braking state is "5" and "7", the adjustment stroke value D of the piston is calculated to be "0.11" and "0.16" respectively, corresponding to "5" and "7".

[0109] The control unit 220 further controls the motor drive unit 210 to rotate the motor 161, causing the piston 110 to advance (1180) in accordance with the calculated adjustment stroke value of the piston 110. For example, the control unit 220 controls the motor drive unit 210 in accordance with the piston adjustment stroke value D, namely "0.11" and "0.16". The motor 161 generates a rotational force in the direction of brake release in accordance with the calculated adjustment stroke value of the piston 110.

[0110] Traditional electromechanical braking systems use electronic brake pad wear sensors or mechanical brake pad wear sensors to sense the wear condition of the brake pads.

[0111] As described above, the electromechanical braking system 200 of one embodiment does not utilize an electronic brake pad wear sensor or a mechanical brake pad wear sensor. Instead, it calculates the first rotation angle and the second rotation angle of the spindle 121 based on the first rotation angle information and the second rotation angle information of the motor 161 obtained by the motor position sensor 142. When there is a difference between the calculated first rotation angle and the calculated second rotation angle, the driver is notified in real time of the wear status of the brake pads 10 through the notification device 300.

Claims

1. An electromechanical brake system including an actuator of an electromechanical brake that operates by a motor, the electromechanical brake system including: a motor drive section that drives the motor; and a control section that is electrically connected to the motor drive section, when the electromechanical brake is in a brake operation mode, the control section calculates a first rotation angle of a main shaft that rotates by driving of the motor, when the electromechanical brake is in a brake operation release mode, the control section calculates a second rotation angle of the main shaft, when there is a difference between the calculated first rotation angle and the calculated second rotation angle, the control section controls a notification device to notify a wear state of a brake pad.

2. The electromechanical brake system according to claim 1, wherein the control section receives first rotation angle information of the motor obtained by a motor position sensor when the brake operation mode, and calculates the first rotation angle of the main shaft based on the received first rotation angle information of the motor, the control section receives second rotation angle information of the motor obtained by the motor position sensor when the brake operation release mode, and calculates the second rotation angle of the main shaft based on the received second rotation angle information of the motor.

3. The electromechanical brake system according to claim 1, wherein the brake operation mode includes at least one of a mode for performing a brake operation of the electromechanical brake and a mode for performing a compensation brake operation of the electromechanical brake for brake pad wear.

4. The electromechanical brake system according to claim 1, wherein the brake operation release mode includes at least one of a mode for performing a brake release operation of the electromechanical brake and a mode for performing a compensation brake release operation of the electromechanical brake for a drag phenomenon.

5. The electromechanical brake system according to claim 1, wherein the control section controls the notification device to notify a wear state of a brake pad related to a corresponding electromechanical brake among a front wheel electromechanical brake and a rear wheel electromechanical brake.

6. The electromechanical brake system according to claim 1, wherein the notification device is a meter center box located between a driver's seat and a front passenger's seat.

7. The electromechanical brake system according to claim 1, wherein when there is a difference between the calculated first rotation angle and the calculated second rotation angle, the control section further calculates an adjustment stroke value of a piston corresponding to a difference value of the rotation angles, in order to advance a relative position of the piston corresponding to the calculated adjustment stroke value of the piston, the control section further controls the motor drive section to rotate the motor.

8. A control method of an electromechanical brake system including an actuator of an electromechanical brake that operates by a motor, the control method of the electromechanical brake system including: when the electromechanical brake is in a brake operation mode, calculating a first rotation angle of a main shaft that rotates by driving of the motor, When the above-described electromechanical brake is in the brake operation release mode, a second rotational angle of the above-described main shaft is calculated, When there is a difference between the above-described calculated first rotational angle and the above-described calculated second rotational angle, a wear state of the brake pad is notified.

9. The control method of the electromechanical brake system according to claim 8, wherein, In the step of calculating the first rotational angle of the main shaft, first rotational angle information of the motor obtained by the motor position sensor in the brake operation mode is received, and the first rotational angle of the main shaft is calculated based on the received first rotational angle information of the motor.

10. The control method of the electromechanical brake system according to claim 8, wherein, In the step of calculating the second rotational angle of the main shaft, second rotational angle information of the motor obtained by the motor position sensor in the brake operation release mode is received, and the second rotational angle of the main shaft is calculated based on the received second rotational angle information of the motor.

11. The control method of the electromechanical brake system according to claim 8, wherein, In the step of notifying the wear state of the brake pad, the wear state of the brake pad related to the corresponding electromechanical brake among the front wheel electromechanical brake and the rear wheel electromechanical brake is notified.

12. The control method of the electromechanical brake system according to claim 8, wherein, further comprising the steps of: When there is a difference between the above-described calculated first rotational angle and the above-described calculated second rotational angle, a stroke adjustment value of the piston corresponding to the difference value of the rotational angle is further calculated, in order to advance the relative position of the piston corresponding to the above-described calculated stroke adjustment value of the piston, the motor is rotated.

Images