Actuator and brake system including the same

Abstract

The invention relates to an actuator and a brake system including the same. The actuator may include: a first gear configured to be rotated by a motor; a second gear operably connected to the first gear and configured to convert rotational movement of the first gear into linear movement; and a foot portion configured to linearly move together with the second gear to move a back plate of the brake pad. A stopper protrusion may be provided at one end portion of the first gear, and a foot may have a stopper groove having a substantially circular arc or partially circular shape such that the stopper protrusion rotating together with the first gear can be inserted into the stopper groove, and when the foot becomes closer to one end portion of the first gear, the stopper protrusion may be inserted into the stopper groove to prevent the first gear from rotating.

Description

Technical Field

[0001] The present disclosure generally relates to an actuator and a brake system including the same, and more particularly, to an actuator including a stopper for preventing a sticking phenomenon caused by excessive release of an electromechanical brake and a brake system including the same. Background Art

[0002] A braking system for brakes is vital to a vehicle, and various types of braking systems have been developed for the safety of drivers and passengers.

[0003] Existing brake systems have generally used a method in which, when a driver steps on a brake pedal, hydraulic pressure for brakes is supplied to a wheel cylinder through a booster mechanically connected to the brake pedal. However, recently, for the convenience of the driver, an electromechanical brake system is being developed that brakes the vehicle by receiving the driver's intention to brake as an electrical signal and operating a transmission device such as a motor based on the electrical signal.

[0004] The electromechanical brake system provides a clamping force of the brake disc by receiving power from an actuator including a motor and a reducer, and performs the service brake or parking brake of the vehicle through the clamping pressure. A ball screw device is used to convert the rotary power from the motor into linear movement, thereby applying a clamping force or pressure to the brake disc.

[0005] In a brake system using a ball screw device, when the brake pad is over-retracted, the ball nut contacts the screw shaft or the foot connected to the screw shaft in the axial direction, which may cause a sticking phenomenon. Generally, since the electromechanical brake system performs position control of the motor through a controller, the excessive withdrawal of the brake pad can be prevented by the controller when the brake is released.

[0006] However, when the position control of the motor fails due to an error of the controller, a stuck phenomenon may occur. When a stuck phenomenon occurs, it may be difficult to release the stuck phenomenon using only the driving force of the motor. In this case, vehicle maintenance is required, such as disassembling the brake system. Summary of the invention

[0007] According to an actuator and a brake system including the actuator according to some embodiments of the present disclosure, the actuator can prevent a sticking phenomenon of a ball screw device caused by excessive release when the brake is released.

[0008] According to an actuator and a brake system including the actuator according to certain embodiments of the present disclosure, the actuator can use a position where rotation is stopped by a stopper as a reference point for motor control.

[0009] Additional aspects of the disclosure will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosure.

[0010] According to an embodiment, an actuator may include: a first gear, which is configured to rotate by receiving a rotational force from a motor; a second gear, which is connected to the first gear on the same axis as the first gear through a ball screw method and is configured to convert the rotational motion of the first gear into a linear motion; and a foot, which is provided at one side of the second gear and is configured to move linearly together with the second gear to press a back plate of an inner brake pad away from the first gear, wherein a stopper protrusion may be provided at one end of the first gear in such a manner as to be spaced apart from the axis in a radial direction by a preset distance, and the foot may be provided with a stopper groove having a radius corresponding to the preset distance from the axis and in a circular arc shape, so that the stopper protrusion rotating with the first gear is inserted into the stopper groove, and when the foot becomes close to one end of the first gear, the stopper protrusion may be inserted into the stopper groove to prevent the first gear from rotating.

[0011] The foot may be configured to prevent the foot from rotating relative to the back plate by contacting the back plate, and the second gear may be configured to prevent the second gear from rotating relative to the back plate by coupling to the foot.

[0012] The foot may be provided with an anti-rotation groove, and the anti-rotation protrusion provided in the back plate is inserted into the anti-rotation groove.

[0013] The first gear may be a ball nut, the second gear may be a screw shaft, a flange portion protruding outward in a radial direction may be integrally provided at an outer periphery of one end of the first gear, and the stopper protrusion may protrude from the flange portion.

[0014] A protrusion height of the stopper protrusion may be greater than a pitch of the screw shaft.

[0015] A depth of the stopper groove may be greater than the protrusion height of the stopper protrusion.

[0016] The stopper groove may have an arc shape having a central angle of 180 degrees or more.

[0017] The stopper protrusion may be configured to first contact an end of the arc rather than a bottom of the stopper groove when the foot becomes close to one end of the first gear.

[0018] According to an embodiment, a brake system including an inner brake pad and an outer brake pad respectively positioned at both sides of a brake disc may include: a motor configured to provide rotational power; a gear assembly configured to transmit the rotational power of the motor; and an actuator configured to press the inner brake pad by receiving the rotational power from the gear assembly, wherein the actuator may include: a first gear configured to rotate by receiving the rotational force with the aid of the gear assembly; a second gear connected to the first gear on the same axis as the first gear by a ball screw method and configured to convert the rotational motion of the first gear into a linear movement; and a foot, which is arranged at one side of the second gear and is configured to move linearly with the second gear to press the back plate of the inner brake pad away from the first gear, wherein a stop protrusion can be arranged at one end of the first gear in such a way as to be spaced a preset distance from the axis in the radial direction, and the foot can be provided with a stop groove having a radius corresponding to the preset distance from the axis and in the shape of a circular arc, so that the stop protrusion is inserted into the stop groove, and when the foot becomes close to one end of the first gear, the stop protrusion can be inserted into the stop groove to prevent the first gear from rotating.

[0019] The foot may be configured to prevent the foot from rotating relative to the back plate by contacting the back plate, and the second gear may be configured to prevent the second gear from rotating relative to the back plate by coupling to the foot.

[0020] The foot may be provided with an anti-rotation groove, and the anti-rotation protrusion provided in the back plate is inserted into the anti-rotation groove.

[0021] The first gear may be a ball nut, the second gear may be a screw shaft, a flange portion protruding outward in a radial direction may be integrally provided at an outer periphery of one end of the first gear, and the stopper protrusion may protrude from the flange portion.

[0022] A protrusion height of the stopper protrusion may be greater than a pitch of the screw shaft.

[0023] The stopper groove may have a depth greater than a pitch of the screw shaft.

[0024] The brake system may further include a caliper in which the actuator is accommodated, wherein a bearing may be provided between the flange portion and the caliper.

[0025] The bearing may be a thrust bearing.

[0026] A gear portion configured to transmit rotational power by engaging with the gear assembly may be provided at the other end of the first gear.

[0027] The stopper groove may be in the shape of a circular groove having a central angle of 180 degrees or more.

[0028] The stopper protrusion may be configured to first contact an end of the arc rather than a bottom of the stopper groove when the foot becomes close to one end of the first gear.

[0029] The braking system may further include a controller configured to control driving of the motor, wherein the controller may be configured to detect a position where rotation is prevented by the stopper protrusion and the stopper groove, and use the detected position as a reference position for controlling the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] These and / or other aspects of the present disclosure will become apparent and more readily understood through the following description of embodiments in conjunction with the accompanying drawings, in which:

[0031] Figure 1 is a perspective view showing a braking system according to an embodiment of the present disclosure;

[0032] Figure 2 is a cross-sectional view showing a portion of a brake system according to an embodiment of the present disclosure;

[0033] Figure 3 is a perspective view showing an actuator according to an embodiment of the present disclosure;

[0034] Figure 4 and Figure 5 is an exploded perspective view of an actuator according to an embodiment of the present disclosure;

[0035] Figure 6 is a side view of the actuator in a state in which the stopper protrusion is positioned outside the stopper groove according to an embodiment of the present disclosure;

[0036] Figure 7 is a side view of an actuator in a state in which a stopper protrusion is inserted into a stopper groove according to an embodiment of the present disclosure;

[0037] Figure 8 is a front view of a foot portion in a state in which a stopper protrusion contacts an end of an arc of a stopper groove according to an embodiment of the present disclosure; and

[0038] Fig. 9 is a cross-sectional view of a stopper groove in a state in which a stopper protrusion contacts an end portion of an arc of the stopper groove according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0039] Figure 1 is a perspective view showing a brake system according to an embodiment of the present disclosure, and Figure 2 is a cross-sectional view showing a portion of a brake system according to an embodiment of the present disclosure.

[0040] refer to Figure 1 and Figure 2 The brake system according to an embodiment of the present disclosure may include an inner brake pad 20 and an outer brake pad 30 respectively positioned at both sides of a brake disc. The brake system may further include: a motor 200 configured to generate or provide a rotational force or power; a gear assembly 300 configured to transmit the rotational power of the motor 200; an actuator 100 configured to move the inner brake pad 20 in response to the rotational power received from the gear assembly 300, such as pressing the inner brake pad 20; a caliper 10 in which the actuator 100 is accommodated; and a controller 400 configured to control the motor 200.

[0041] The motor 200 may be operated by receiving power from a power source such as a battery of the vehicle, and generate and provide power for braking the vehicle. For example, the motor 200 may be accommodated in and supported by a motor accommodating portion formed by recessing one side of the housing, and the motor 200 may be operated according to an electrical signal transmitted from an electronic control unit (ECU) of the controller 400. The drive gear 310 to be described below may be coupled to a drive shaft of the motor 200, and details about the drive gear 310 will be described below.

[0042] The gear assembly 300 can reduce the rotational force or power provided from the motor 200 and transmit the reduced rotational power to the actuator 100. The gear assembly 300 may include, for example but not limited to: a driving gear 310, which is provided on the driving shaft of the motor 200; a first reduction gear 330, which is rotatably connected to the driving gear 310 of the motor 200 and is configured to transmit the rotational force or power received from the driving gear 310; a second reduction gear 340, which is connected to the first reduction gear 330 and is configured to transmit the rotational power received from the first reduction gear 330; and a third reduction gear 350, which is rotatably connected to the second reduction gear 340 or engaged with the second reduction gear 340 and is configured to transmit the received rotational power to the actuator 100.

[0043] The driving gear or pulley 310 may be coupled to a driving shaft of the motor 200 and rotated together with the driving shaft by the operation or rotational force of the motor 200. The driving gear or pulley 310 may mainly reduce the rotational force or power provided from the motor 200 or generated by the motor 200 through the belt 320, and then transmit the reduced rotational power to the first reduction gear 330, which will be described below.

[0044] The first reduction gear 330 may receive the rotational force or power transmitted from the driving gear 310 and transmit the rotational force or power to the second reduction gear 340, which will be described below. The first reduction gear 330 may be provided at one side or one end portion of a gear shaft or a connecting shaft extending in the axial direction and at the other side or the other end portion of the gear shaft or the connecting shaft, and the second reduction gear 340 may be provided to transmit the rotational force or power transmitted from the driving gear 310 to the second reduction gear 340. The rotation axis of the gear shaft or the connecting shaft may be parallel to the driving shaft of the motor 200, and the gear shaft or the connecting shaft may be accommodated in a housing of the brake system.

[0045] The second reduction gear 340 may receive the rotational force or power transmitted from the first reduction gear 330 and transmit the received rotational force or power to the third reduction gear 350. The second reduction gear 340 may be rotatably engaged with the third reduction gear 350 and transmit the rotational force or power to the third reduction gear 350.

[0046] The actuator 100 may receive a rotational force or power from the gear assembly 300, and is configured to move the inner brake pad 20, for example, press the inner brake pad 20, in response to the rotational force or power from the gear assembly 300. For example, the actuator 100 may be accommodated in the caliper 10. The inner brake pad 20 and the outer brake pad 30 may be positioned on or at both sides of the brake disc, respectively, and when the inner brake pad 20 is pressed or moved by the actuator 100, the finger-shaped portion of the caliper 10 may press or move the outer brake pad 30 by a reaction force. Therefore, the inner brake pad 20 and the outer brake pad 30 may press or clamp the brake disc at both sides, respectively, so that braking may be performed by friction.

[0047] The actuator 100 may include: a first gear (or rotatable portion) 120, which is configured to rotate by performing a rotational motion according to a rotational force or power received by means of the gear assembly 300; a second gear (or translatable portion) 110, which is operably connected to the first gear 120, is coaxially arranged with the first gear 120 on the same axis as the first gear 120 by, for example but not limited to, a ball screw mechanism or method, and is configured to translate by converting the rotational motion of the first gear 120 into a linear motion; and a foot or base 130, which is disposed at one side of the second gear 110 or connected to an end portion of the second gear 110, and is configured to move linearly together with the second gear (or translatable portion) 110 to press the back plate 22 of the inner brake pad 20 in a direction away from the first gear 120.

[0048] In an exemplary embodiment of the present disclosure, the first gear 120 may be a ball nut, and the second gear 110 may be a screw shaft, although not required. The ball nut may be connected to the screw shaft by a ball screw mechanism or method, and when the ball nut rotates, the rotation of the ball nut causes the screw shaft, whose rotation is blocked, to move linearly.

[0049] For example, according to an embodiment of the present disclosure, the foot or base 130 cannot rotate or can be prevented from rotating relative to the back plate 22 by contacting the back plate 22 of the inner brake pad 20, and the second gear (or translatable portion) 110 cannot rotate or can be prevented from rotating relative to the back plate 22 by being coupled to the foot or base 130. In this way, in a state in which the axial rotation of the second gear 110 is prevented, the motor 200 can provide a rotational force or power to the first gear (or rotatable portion) 120 operably connected to the second gear (or translatable portion) 110 through a ball screw mechanism or method, so that the second gear (or translatable portion) 110 moves linearly.

[0050] Alternatively, according to another embodiment of the present disclosure, the first gear (or rotatable part) 120 may be a screw shaft, and the second gear (or translatable part) 110 may be a ball nut. The ball nut may be connected to the screw shaft by a ball screw mechanism or method, and when the screw shaft rotates, the rotation of the screw shaft causes the ball nut, whose rotation is blocked, to move linearly.

[0051] Hereinafter, the actuator 100 according to an embodiment of the present disclosure will be described in more detail.

[0052] Figure 3 is a perspective view showing an actuator according to an embodiment of the present disclosure, and Figure 4 and Figure 5 is an exploded perspective view of an actuator according to an embodiment of the present disclosure.

[0053] refer to Figures 3 to 5 , the foot or base 130 may be directly or indirectly coupled to or in contact with the back plate 22 of the inner brake pad 20, and the second gear (or translatable portion) 110 may be coupled to the foot or base 130 by, for example, but not limited to, a coupling screw 150. For example, the first gear (or rotatable portion) 120 may be connected to the second gear (or translatable portion) 110 by a ball screw mechanism or method.

[0054] The foot or base 130 may include an anti-rotation groove 132 into which an anti-rotation protrusion provided in the back plate 22 is inserted, so that the foot or base 130 cannot rotate. When the foot 130 contacts the back plate 22, the anti-rotation protrusion of the back plate 22 may be inserted into the anti-rotation groove 132, thereby preventing the foot or base 130 from rotating.

[0055] The foot or base 130 may be coupled to the second gear (or translatable portion) 110 by a coupling screw 150. The coupling screw 150 may be threadedly connected or inserted into a screw coupling hole 115 provided in an end portion of the second gear (or translatable portion) 110 by penetrating the foot 130 to couple the foot or base 130 to the second gear (or translatable portion) 110.

[0056] In this example, the anti-rotation coupling 113 may be provided at the end of the second gear (or translatable portion) 110. The anti-rotation coupling 113 may have, for example but not limited to, a polygonal shape, preferably a gear tooth shape. The anti-rotation coupling 113 may be inserted into an anti-rotation coupling groove 133 provided on the foot 130. The anti-rotation coupling groove 133 may be provided as a groove having a shape corresponding to the shape of the anti-rotation coupling 113 or a shape that can be fixedly coupled to the shape of the anti-rotation coupling 113 to prevent rotational movement of the second gear (or translatable portion) 110 when the anti-rotation coupling 113 is inserted.

[0057] A flange portion 122 protruding outward in a radial direction may be integrally provided at the outer periphery of one end portion of the first gear (or rotatable portion) 120. Also, a gear portion 123 rotatably engaged with the gear assembly 300 to transmit a rotational force or power may be provided at the other end of the first gear (or rotatable portion) 120. The gear portion 123 may receive the rotational force or power by rotatably engaging with the third reduction gear 350 of the gear assembly 300 to rotate the first gear (or rotatable portion) 120.

[0058] Meanwhile, the bearing 140 may be provided between the first gear (or rotatable part) 120 and the caliper 10 (or any non-rotatable structure of the vehicle) to rotatably support the first gear (or rotatable part) 120. For example, the bearing 140 may be positioned between the flange portion 122 and the caliper 10, and the bearing 140 may be a thrust bearing. If the bearing 140 is a thrust bearing positioned between the flange portion 122 and the caliper 10, the first gear (or rotatable part) 120 may be easily rotated inside the caliper 10 regardless of the reaction force transmitted when the foot or base 130 presses the inner brake pad 20 by the linear movement of the second gear (or translatable part) 110.

[0059] refer to Figure 5 The stopper protrusion 121 may be provided at one end portion of the first gear (or rotatable portion) 120 in such a manner as to be spaced apart from the rotation axis in the radial direction. The stopper protrusion 121 may protrude from the flange portion 122.

[0060] In addition, reference Figure 4 The foot or base 130 may be provided with a stopper groove 131 having a radius corresponding to a preset distance from the axis. For example, the stopper groove 131 of the foot or base 130 is in the shape of an arc or a part of a circle, so that the stopper protrusion 121 is inserted into the stopper groove 131.

[0061] The second gear (or translatable portion) 110 may be linearly moved in the axial direction by the rotation of the first gear 120, and the foot or base 130 fixedly coupled to the second gear (or translatable portion) 110 may be linearly moved in the axial direction together with the second gear (or translatable portion) 110. When the foot or base 130 moves closer to one end of the first gear (or rotatable portion) 120, the stopper protrusion 121 of the first gear (or rotatable portion) 120 may be inserted into the stopper groove 131 of the foot or base 130 to prevent the first gear (or rotatable portion) 120 from rotating.

[0062] like Figure 4 As shown in , the stopper groove 131 may be in the shape of an arc or a part of a circle. Because the stopper groove 131 is in the shape of an arc or a part of a circle, the stopper protrusion 121 that rotates according to the rotation of the first gear (or rotatable part) 120 may rotate within a preset angle range in a state of being inserted into the stopper groove 131, and when the stopper protrusion 121 contacts the end of the arc or the part of the circle of the stopper groove 131, the first gear 120 may be prevented from rotating.

[0063] At the same time, Figures 3 to 5In the exemplary embodiment shown in , the stopper groove 131 is provided in or on the foot 130, and the stopper protrusion 121 may be provided in or on the first gear (or rotatable part) 120, although not required. Alternatively, the stopper protrusion 121 may be provided in or on the foot or base 130, and the stopper groove 131 may be provided in or on the first gear (or rotatable part) 120.

[0064] Figure 6 is a side view of the actuator in a state in which the stopper protrusion is positioned outside the stopper groove according to an embodiment of the present disclosure, and Figure 7 is a side view of an actuator in a state in which a stopper protrusion is inserted into a stopper groove according to an embodiment of the present disclosure.

[0065] The foot or base 130 fixedly coupled to the second gear (or translatable portion) 110 may be linearly movable by rotation of the first gear 120, the second gear (or translatable portion) 110 being configured to be linearly movable in response to rotation of the first gear (or rotatable portion) 120. Figure 6 , the foot 130 may be spaced apart from one end of the first gear (or rotatable part) 120. Therefore, because the stopper protrusion 121 is positioned outside the stopper groove 131 of the foot 130, the first gear (or rotatable part) 120 may be freely rotated without any limitation of the rotatable range, and the foot 130 may be linearly moved according to the rotation of the first gear (or rotatable part) 120 to press the back plate 22 of the brake pad 20. In this way, the foot 130 may press the back plate 22 so that the friction material 21 of the brake pad 20 may contact the brake disc to perform braking.

[0066] At the same time, if Figure 7 As shown in , when the foot 130 further moves linearly toward the first gear (or rotatable part) 120 by the rotation of the first gear (or rotatable part) 120, the stopper protrusion 121 of the first gear 120 may be inserted into the stopper groove 131 of the foot 130. Then, the stopper protrusion 121 may contact the arc or partially circular end of the stopper groove 131, and this may result in preventing the first gear (or rotatable part) 120 from rotating further. Therefore, the foot 130 may not directly contact the first gear (or rotatable part) 120 in the axial direction, and a sticking phenomenon caused by axial contact may be prevented.

[0067] Figure 8 is a front view of a foot portion in a state in which a stopper protrusion contacts an end of an arc of a stopper groove according to an embodiment of the present disclosure, and Fig. 9is a cross-sectional view of a stopper groove in a state in which a stopper protrusion contacts an end portion of an arc of the stopper groove according to an embodiment of the present disclosure.

[0068] Figure 8 A state in which the stopper protrusion 121 inserted into the stopper groove 131 having an arc shape contacts an arc or partially circular end portion 131 a of the stopper groove 131 is shown.

[0069] like Figure 8 As shown in , the stopper groove 131 may be in the shape of an arc or a part of a circle with a central angle of 180 degrees or more. More preferably, the stopper groove 131 may be in the shape of an arc or a part of a circle with a central angle of 270 degrees or more to limit the rotatable angle of the first gear (or rotatable part) 120, thereby preventing contact between the foot or base 130 and the first gear (or rotatable part) 120. The stopper protrusion 121 may rotate with the first gear (or rotatable part) 120, and when the foot 130 becomes gradually close to the stopper protrusion 121 by the rotation of the first gear (or rotatable part) 120, the stopper protrusion 121 may be inserted into the stopper groove 131 while rotating. The stopper groove 131 may be in the shape of an arc or a partial circle with a central angle of 180 degrees or more, preferably 270 degrees or more, so that the stopper protrusion 121 is inserted into the stopper groove 131 when rotated to a preset angle or more.

[0070] At the same time, reference Fig. 9 According to an embodiment of the present disclosure, when the foot 130 becomes closer to one end of the first gear (or rotatable part) 120, the stopper protrusion 121 may contact the arc or partially circular end 131a of the stopper groove 131 instead of the bottom 131b of the stopper groove 131.

[0071] Even when the foot 130 becomes closer to the first gear 120, the stopper protrusion 121 and the stopper groove 131 may be configured not to allow the foot 130 to directly contact the first gear (or rotatable part) 120 in the axial direction to prevent a sticking phenomenon. To this end, before the foot 130 contacts the first gear (or rotatable part) 120, the stopper protrusion 121 may contact the stopper groove 131 to prevent the end of the first gear 120 from directly contacting the foot 130 in the axial direction, and the stopper protrusion 121 may contact the arc or partially circular end 131a instead of the bottom 131b of the stopper groove 131 to prevent the first gear (or rotatable part) 120 from directly contacting the foot 130 in the axial direction.

[0072] For example, the protrusion height of the stopper protrusion 121 may be greater than the pitch of the second gear (or the translatable portion) 110 implemented as a screw shaft.

[0073] Because the first gear (or rotatable part) 120 and the second gear (or translatable part) 110 are connected by a ball screw mechanism or method, when the first gear (or rotatable part) 120 rotates one circle, the second gear (or translatable part) 110 can linearly move the pitch of the screw shaft. Figure 7 ) The distance between the foot portion 130 and the end of the first gear (or rotatable portion) 120 is the same as the distance before the stopper protrusion 121 is inserted into the stopper groove 131 (see Figure 6 ) The difference between the distance between the foot 130 and the end of the first gear (or rotatable part) 120 may be the pitch of the screw shaft. If the protrusion height of the stopper protrusion 121 is smaller than the pitch of the second gear (or translatable part) 110, when the stopper protrusion 121 is inserted into the stopper groove 131, the foot 130 may directly contact the end of the first gear 120 before the stopper protrusion 121 contacts the end 131a of the arc of the stopper groove 131, which may cause a sticking phenomenon. Therefore, according to an embodiment of the present disclosure, the protrusion height of the stopper protrusion 121 may be larger than the pitch of the second gear (or translatable part) 110 implemented as a screw shaft to prevent the foot 130 from directly contacting the end of the first gear (or rotatable part) 120.

[0074] According to an embodiment of the present disclosure, the depth of the stopper groove 131 may be greater than the pitch of the second gear (or the translatable portion) 110 implemented as a screw shaft.

[0075] As described above, each time the first gear (or rotatable part) 120 rotates one circle, the second gear (or translatable part) 110 can move the pitch of the screw shaft. And each time the first gear (or rotatable part) 120 rotates one circle, the foot 130 can also move the pitch of the screw shaft. That is, after the first gear (or rotatable part) 120 rotates one circle (see Figure 7 ) The distance between the bottom 131b of the stopper groove 131 and the end of the stopper protrusion 121 is the same as the distance before the stopper protrusion 121 is inserted into the stopper groove 131 (see Figure 6) The difference between the distances between the bottom 131b of the stopper groove 131 and the end of the stopper protrusion 121 may be the pitch of the screw shaft. If the depth of the stopper groove 131 is less than the pitch of the second gear (or translatable portion) 110, the end of the stopper protrusion 121 may contact the bottom 131b instead of the arc or partially circular end 131a of the stopper groove 131, which may cause a sticking phenomenon. According to an embodiment of the present disclosure, because the depth of the stopper groove 131 is greater than the pitch of the second gear (or translatable portion) 110 implemented as the screw shaft, the stopper protrusion 121 may contact the arc or partially circular end 131a of the stopper groove 131 instead of the bottom 131b of the stopper groove 131 to prevent the first gear 120 from rotating, and therefore, the end of the stopper protrusion 121 cannot directly contact the bottom 131b of the stopper groove 131.

[0076] The braking system according to the embodiment may include a controller 400. The controller 400 may control the operation of braking of the braking system by controlling the motor 200. The controller 400 may be configured as a circuit including devices or electronic components mounted on a printed circuit board (PCB) and provided inside a housing of the braking system (see Figure 1 ).

[0077] The controller 400 may be connected to a motor position sensor configured to detect the rotational position of the motor 200 to control the rotation of the motor 200, thereby controlling the rotation of the first gear (or rotatable part) 120, and controlling the pressing or releasing movement of the brake pads 20 and 30. However, when the controller 400 or the sensor fails or malfunctions, or an error such as error accumulation occurs, the controller 400 may not be able to properly control the motor 200 and the first gear (or rotatable part) 120.

[0078] The controller 400 according to an embodiment of the present disclosure may detect a position where the rotation of the first gear (or rotatable part) 120 is prevented by the stopper protrusion 121 and the stopper groove 131 , and use the detected position as a reference position for controlling the motor 200 .

[0079] Meanwhile, during the rotation of the first gear (or rotatable part) 120, for example, during the reverse rotation for releasing the pressure applied to the brake pads 20 and 30, the stopper protrusion 121 is inserted into the stopper groove 131 to prevent the first gear (or rotatable part) 120 from rotating, and the load applied to the motor 200 may suddenly increase. At this time, the controller 400 may detect the anti-rotation by the stopper protrusion 121 and the stopper groove 131 by means of a sensor such as a motor current sensor or a motor voltage sensor.

[0080] The controller 400 may detect a position where the rotation of the first gear (or rotatable part) 120 is prevented by the stopper protrusion 121 and the stopper groove 131, and use the detected position as a reference position for controlling the motor 200. For example, the controller 400 may set the position where the rotation of the first gear (or rotatable part) 120 is prevented by the stopper protrusion 121 and the stopper groove 131 as an origin or a reference point, increase the value of the position when the motor 200 rotates in a direction for pressing the brake pads 20 and 30 in the forward direction, and control the motor 200 based on the value of the position. In this way, by using the position where the rotation is prevented by the stopper protrusion 121 and the stopper groove 131 as a reference position for controlling the motor 200, the control stability of the motor 200 may be improved.

[0081] An actuator and a brake system including the actuator according to some embodiments of the present disclosure can prevent a sticking phenomenon of a ball screw device caused by excessive release when performing a release of the brake.

[0082] An actuator and a brake system including the actuator according to certain embodiments of the present disclosure may use a position at which rotation of a rotatable portion of the actuator is stopped by a stopper as a reference point for position control.

Claims

1. An actuator, comprising: a first gear configured to be rotatable by a rotational force of a motor; a second gear disposed coaxially with the first gear and configured to translate by converting a rotational motion of the first gear into a linear motion; as well as a foot coupled to the second gear and configured to move linearly with the second gear to move a back plate of the brake pad, in, A stopper protrusion is provided at one end portion of the first gear, and the stopper protrusion is positioned at a distance away from a rotation axis of the first gear, and The foot has a stopper groove having a shape that is roughly an arc or a partial circle and a radius that corresponds to the distance of the stopper protrusion away from the rotation axis of the first gear, so that the stopper protrusion that rotates together with the first gear can be inserted into the stopper groove of the foot according to the rotation of the first gear, and the end portion of the stopper groove of the foot is configured to limit the rotation of the first gear.

2. The actuator according to claim 1, wherein: The foot is fixedly coupled to the back plate to limit rotation of the foot relative to the back plate, and The second gear is fixedly coupled to the foot to restrict rotation of the second gear relative to the back plate.

3. The actuator according to claim 2, wherein: The foot portion has an anti-rotation groove, and the anti-rotation protrusion of the back plate is inserted into the anti-rotation groove.

4. The actuator according to claim 1, wherein: The first gear has a ball nut, The second gear has a screw shaft, and The stopper protrusion protrudes from a flange portion that protrudes outward from one end portion of the first gear in a radial direction.

5. A braking system, comprising: a motor configured to provide rotational power; a gear assembly configured to transmit the rotational power of the motor; as well as an actuator configured to move a brake pad in response to the rotational power from the gear assembly, Wherein, the actuator comprises: a first gear configured to be rotatable by the rotational power received via the gear assembly; a second gear coaxially disposed with the first gear and configured to translate by converting a rotational motion of the first gear into a linear motion; and a foot coupled to the second gear and configured to move linearly with the second gear to move a back plate of the brake pad, wherein a stopper protrusion is provided at one end portion of the first gear, and the stopper protrusion is positioned at a distance away from a rotation axis of the first gear, and The foot is provided with a stopper groove having a shape of a roughly circular arc or a partial circle with a radius corresponding to the distance of the stopper protrusion away from the rotation axis of the first gear, so that the stopper protrusion can be inserted into the stopper groove of the foot according to the rotation of the first gear, and the end portion of the stopper groove of the foot is configured to limit the rotation of the first gear.

6. The braking system according to claim 5, wherein: The first gear has a ball nut, The second gear has a screw shaft, and The stopper protrusion protrudes from a flange portion that protrudes outward from one end portion of the first gear in a radial direction.

7. The braking system according to claim 6, wherein: A protrusion height of the stopper protrusion protruding from the flange portion of the first gear is greater than a pitch of the screw shaft of the second gear.

8. The braking system according to claim 7, wherein: The stopper groove of the foot portion has a depth greater than a pitch of the screw shaft of the second gear.

9. The braking system according to claim 6, further comprising: a caliper in which the actuator is housed; as well as A bearing is provided between the caliper and the flange portion, the bearing protruding from the flange portion of the first gear.

10. The brake system according to claim 5, further comprising a controller configured to control the motor, in, The controller is configured to detect a position where rotation of the first gear is stopped by the stopper protrusion of the first gear and the stopper groove of the foot, and set the detected position as a reference position for controlling the motor.

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