BRAKE ACTUATOR AND BRAKE APPARATUS INCLUDING THE SAME

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 10-2023-0189869, filed on Dec. 22, 2023, which is hereby incorporated by reference for all purposes as if set forth herein.

BACKGROUND
Technical Field

Exemplary embodiments of the present disclosure relate to a brake actuator and a brake apparatus including the same, and more particularly, to a brake actuator and a brake apparatus including the same, which are capable of ensuring stable parking braking performance.

Discussion of the Background

A vehicle brake apparatus generally serves to brake a vehicle by pushing a piston with driving force to bring a pad into close contact with a disc and thus using frictional force between the pad and the disc.

Among others, an electro mechanical brake (EMB) is to generate braking force by mounting a motor-driven actuator directly to a caliper without using hydraulic pressure and pressing a piston through mechanisms such as gears and screws. Such an EMB is capable of performing active braking and wheel-specific independent braking, enabling implementation of additional functions such as ABS, ESC, TCS, and AEB as well as of typical main braking. The EMB is also able to achieve higher performance because there is no delay of hydraulic transmission.

A conventional EMB ensures fast piston response and high efficiency through ball screws. However, these ball screws are impossible, due to the structural characteristics thereof, in self-locking that is allowed to limit their own rotation. Hence, if supply of power to motors is interrupted, braking force may be arbitrarily released by repulsive force between a pad and a piston.

The related art of the present disclosure is disclosed in Korean Patent Application Publication No. 10-2010-0098846 (published on Sep. 10, 2010, entitled “DISC BRAKE WITH PARKING FUNCTION”).

SUMMARY

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Various embodiments are directed to a brake actuator and a brake apparatus including the same, which are capable of ensuring stable parking braking performance.

In an embodiment, a brake actuator includes a casing, a first motor mounted in the casing, a transmission gear rotatably mounted in the casing and connected to the first motor, a first parking member engaged to the first motor and configured to rotate together with the transmission gear, a second motor spaced apart from the first motor, and a second parking member mounted to be rotatable and linearly movable in the casing and configured to selectively limit rotation of the first parking member by operation of the second motor.

The first parking member may include a first parking body connected to a first output shaft of the first motor, and a plurality of extension parts extending from the first parking body and arranged along a circumferential surface of the first parking body.

Each of the extension parts may extend obliquely with respect to a radial direction of the first parking body.

The second parking member may include a second parking body, a guide rail formed through the second parking body, a second output shaft of the second motor being inserted into the guide rail, and a latch extending from the second parking body and inserted between an associated pair of neighboring extension parts as the second parking body is rotated in a first rotation direction. The second parking body may be rotated at the same angular speed as the second output shaft, and may be moved linearly in a first direction as the latch is inserted between the associated pair of neighboring extension parts.

A longitudinal direction of the guide rail may extend in a direction parallel to the first direction.

A width of the guide rail perpendicular to the first direction may be smaller than one of the widths of the second output shaft perpendicular to its longitudinal direction.

The second parking member may further include a first return member connected to the second parking body and configured to press the second parking body in a second rotation direction opposite to the first rotation direction, and a second return member connected to the second parking body and configured to press the second parking body in a second direction opposite to the first direction.

The first return member may be configured to be elastically deformable, and first and second ends of the first return member may be connected to the second motor and the second parking body, respectively.

The first return member may be a torsion spring.

The second return member may be configured to be elastically deformable, and both ends of the second return member may be connected to the second output shaft and the second parking body, respectively.

The second return member may be a compression spring.

The second parking member may further include a support member configured to limit a range of movement of the second parking body with respect to the first direction.

The support member may include a first stopper extending from the second parking body, and a second stopper disposed to face the first stopper, and configured to contact with the first stopper as the second parking body is moved in the first direction over a set distance.

The second stopper may extend from the casing.

The first parking body may be mounted to be movable in a longitudinal direction of the first output shaft. When a reaction force acting between an associated one of the extension parts and the latch increases beyond a set magnitude, the first parking body may be moved in a departure direction parallel to the longitudinal direction of the first output shaft.

The extension part may have a side surface inclined with respect to the longitudinal direction of the first output shaft.

The brake actuator may further include a restoration member configured to move the first parking member in a direction opposite to the departure direction.

The restoration member may be configured to be elastically deformable in a direction parallel to the longitudinal direction of the first output shaft, and first and second ends of the restoration member may be in contact with the first parking body and the transmission gear, respectively.

The restoration member may be a compression spring.

In another embodiment, a brake apparatus includes a caliper body, a piston unit movably mounted on the caliper body, and a brake actuator connected to the piston unit and configured to move the piston unit. The brake actuator includes a casing, a first motor mounted in the casing, a transmission gear rotatably mounted in the casing and connected to the first motor, a first parking member engaged to the first motor and configured to rotate together with the transmission gear, a second motor spaced apart from the first motor, and a second parking member mounted to be rotatable and linearly movable in the casing and configured to selectively limit rotation of the first parking member by operation of the second motor.

As apparent from the above description, the brake actuator and brake apparatus according to the present disclosure can maintain parking braking force even if the operation of the first motor is released during parking braking by the first parking member and the second parking member.

The brake actuator and brake apparatus according to the present disclosure can return the second parking body to its initial position without driving the second motor by the first return member and the second return member, thereby controlling the operation of the second parking body only by the ON/OFF control of the second motor.

The brake actuator and brake apparatus according to the present disclosure can prevent damage to the second output shaft by distributing the reaction force, generated between the extension part and the latch during parking braking, through the support member.

The brake actuator and brake apparatus according to the present disclosure can prevent the vehicle from losing its driving ability by forcibly releasing the braking force by the inclined structure of the extension part and the restoration member when the braking force is not smoothly released due to damage or malfunction of the first and second parking members.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view schematically illustrating a configuration of a brake apparatus according to an embodiment of the present disclosure.

FIG. 2 is a cross-sectional view schematically illustrating the configuration of the brake apparatus according to the embodiment of the present disclosure.

FIG. 3 is a perspective view schematically illustrating a configuration of a brake actuator according to the embodiment of the present disclosure.

FIG. 4 is a front view schematically illustrating the configuration of the brake actuator according to the embodiment of the present disclosure.

FIG. 5 is a perspective view schematically illustrating a configuration of a first parking member and a second parking member according to the embodiment of the present disclosure.

FIG. 6 is a front view schematically illustrating the configuration of the first parking member and the second parking member according to the embodiment of the present disclosure.

FIG. 7 is an enlarged view schematically illustrating a configuration of a guide rail according to the embodiment of the present disclosure.

FIG. 8 is a view schematically illustrating an installation state of a restoration member according to the embodiment of the present disclosure.

FIGS. 9 to 11 are views schematically illustrating a process of generating parking braking force.

FIGS. 12 to 14 are views schematically illustrating a process of releasing parking braking force.

FIGS. 15 and 16 are views schematically illustrating a process of forcibly releasing parking braking force.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Exemplary embodiments of the present disclosure will be described below with reference to the accompanying drawings.

It should be considered that the thickness of each line or the size of each component in the drawings may be exaggeratedly illustrated for clarity and convenience of description. In addition, the terms used herein are terms defined in consideration of functions of the present disclosure, and these terms may change depending on the intention or practice of a user or an operator. Therefore, these terms should be defined based on the entirety of the disclosure set forth herein.

In the specification, it will be understood that when an element is referred to as being “connected (or joined)” to another element, it can be “directly connected (or joined)” to the other element or it can be “indirectly connected (or joined)” to the other element with other elements being interposed therebetween. In the specification, it will be understood that when a component is referred to as “comprising (or including)” any component, it does not exclude other components, but can further comprise (or include) the other components unless otherwise specified.

Throughout the specification, like reference numerals may refer to like components. Even if the same or similar reference numerals are not mentioned or described in a particular drawing, they may be described based on other drawings. In addition, even if there is an element that is not marked with a reference numeral in a specific drawing, that element may be described based on other drawings. Moreover, the number, shape, size, relative difference, and the like of the detailed components represented in the drawings herein are set for convenience of understanding, and may be implemented in various forms without limiting the embodiments thereof.

FIG. 1 is a perspective view schematically illustrating a configuration of a brake apparatus according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view schematically illustrating the configuration of the brake apparatus according to the embodiment of the present disclosure.

Referring to FIGS. 1 and 2, the brake apparatus, which is designated by reference numeral 1, according to the present embodiment includes a caliper body 10, a piston unit 20, and a brake actuator 30.

The caliper body 10 may define a schematic appearance of the brake apparatus and support the piston unit 20 and the brake actuator 30 as a whole.

The caliper body 10 according to this embodiment may include a bridge 11, a finger 12, and cylinder 13.

The bridge 11 may define a central appearance of the caliper body 10 and support the finger 12 and the cylinder 13. The bridge 11 may have a lower surface facing a circumferential surface of a brake disc D with spaced at a predetermined distance therefrom. The bridge 11 may have both sides extending in opposite directions along a direction parallel to the central axis of the brake disc D (X-axis direction in FIG. 1). The bridge 11 is not limited to having the shape illustrated in FIGS. 1 and 2, and may be designed and changed into various shapes.

A pair of brake pads P may be arranged on the lower side of the bridge 11. The pair of brake pads P may be spaced apart from each other along the central axis of the brake disc D. The pair of brake pads P may face each other with the brake disc D interposed therebetween. The pair of brake pads P may be supported on a carrier 2 or the bridge 11 so as to be slidable in a direction parallel to the central axis of the brake disc D. A friction pad, which is made of a material with a high coefficient of friction, such as rubber, may be attached to one surface of each of the brake pads P facing the brake disc D.

The bridge 11 may be movably connected to the carrier 2 fixed to a knuckle (not shown) or the like via a guide rod 11a. The bridge 11 may slide in a direction parallel to the central axis of the brake disc D by the reaction force generated between the piston unit 20 and the associated brake pad P during braking of a vehicle.

The finger 12 may extend downward from one side of the bridge 11. The finger 12 may be integrally connected to the bridge 11 by welding, pressing, bending, or the like. The finger 12 may be disposed to face one of the pair of brake pads P. The finger 12 may press or release one of the pair of brake pads P toward or from the brake disc D by sliding the bridge 11.

The cylinder 13 may extend downward from the other side of the bridge 11. The cylinder 13 may have a hollow cylindrical shape with open at one side. The central axis of the cylinder 13 may be parallel to the central axis of the brake disc D. The open side of the cylinder 13 may be disposed to face the remaining one of the pair of brake pads P.

The piston unit 20 may be movably mounted on the caliper body 10. The piston unit 20 may come into contact with or separate from the remaining one of the pair of brake pads (P) depending on the direction of movement thereof. When the piston unit 20 comes into contact with an associated brake pad P, it may press the brake pad P toward the brake disc D so that the brake pad P is in close contact with the brake disc D to apply braking force to the vehicle. The piston unit 20 may release the pressing force applied to the brake pad P when separated from the brake pad P so that the brake pad P is separated from the brake disc D to release the braking force applied to the vehicle.

The piston unit 20 may include a piston 21, a bolt screw 22, and a nut screw 23.

The piston 21 may have a cup shape with open at one side. The closed side of the piston 21 may be directed toward the brake pad P disposed to face the cylinder 13. The open side of the piston 21 may be directed toward the internal space of the cylinder 13. The piston 21 may have an outer surface slidably supported on the inner surface of the cylinder 13. Alternatively, the outer surface of the piston 21 may also be spaced at a predetermined distance from the inner surface of the cylinder 13 to form a gap therebetween.

The piston 21 may move forward and backward in a direction parallel to the central axis of the cylinder 13 (in a direction parallel to the X-axis in FIG. 1). The piston 21 may protrude to the outside of the cylinder 13 when moving forward, and may press the brake pad P, disposed to face the cylinder 13, toward the brake disc D. In this case, the bridge 11 may move in a direction opposite to the direction of movement of the piston 21 by the reaction force generated between the piston 21 and the brake pad P. When the piston 21 moves backward, it may release the pressing force applied to the brake pad P and separate the brake pad P from the brake disc D.

The bolt screw 22 may be disposed inside the cylinder 13 and may be rotated by the driving force received from the brake actuator 30.

As an example, the bolt screw 22 may be in the form of a rod having a substantially circular cross-section. The bolt screw 22 may be disposed inside the cylinder 13, and its central axis may be positioned coaxially with the central axis of the cylinder 13. The bolt screw 22 may have one end facing the inner end surface of the piston 21 with spaced at a predetermined distance therefrom. The bolt screw 22 may have the other end protruding to the outside of the caliper body 10 through the closed side of the cylinder 13. The bolt screw 22 may be rotated clockwise or counterclockwise about the central axis thereof when the brake actuator 30 is operated.

The bolt screw 22 may have a groove, formed on the outer peripheral surface thereof, in which one circumference of a spherical rolling element is seated. The groove may extend spirally in the longitudinal direction of the bolt screw 22 to provide a circulation path for the rolling element.

The nut screw 23 may be disposed inside the cylinder 13 and may be connected to the bolt screw 22. The nut screw 23 may linearly reciprocate in a direction parallel to the longitudinal direction of the bolt screw 22 in conjunction with the rotation of the bolt screw 22 within the cylinder 13. The nut screw 23 may press or release the piston 21 toward or from the brake pad P depending on the direction of movement thereof.

As an example, the nut screw 23 may have a hollow cylindrical shape. The nut screw 23 may have an inner peripheral surface facing the outer peripheral surface of the bolt screw 22 with spaced at a predetermined distance therefrom. The nut screw 23 may have a groove, formed on the inner peripheral surface thereof, in which the other circumference of the spherical rolling element is seated. The groove may extend spirally in the longitudinal direction of the nut screw 23 to provide a circulation path for the rolling element.

The nut screw 23 may receive the rotational force of the bolt screw 22 via the rolling element. When the bolt screw 22 is rotated, the nut screw 23 may move forward and backward in the longitudinal direction of the bolt screw 22 by circulation movement of the rolling element.

When the nut screw 23 moves forward, it may come into contact with the inner surface of the piston 21 to press the piston 21 toward the brake disc D. When the nut screw 23 moves backward, it may be separated from the inner surface of the piston 21 to release the pressing force applied to the piston 21.

The brake actuator 30 may be connected to the piston unit 20 and may move the piston unit 20. In other words, the brake actuator 30 may function as a component that generates driving force for applying or releasing braking force to or from the vehicle and transmits the generated driving force to the piston unit 20.

FIG. 3 is a perspective view schematically illustrating the configuration of the brake actuator according to the embodiment of the present disclosure. FIG. 4 is a front view schematically illustrating the configuration of the brake actuator according to the embodiment of the present disclosure.

Referring to FIGS. 3 and 4, the brake actuator 30 according to this embodiment includes a casing 100, a first motor 200, a transmission gear 300, a first parking member 400, a second motor 500, and a second parking member 600.

The casing 100 may be fixed to the caliper body 10, and may support the first motor 200, the transmission gear 300, the first parking member 400, the second motor 500, and the second parking member 600 as a whole.

The casing 100 may include a casing body 110 and a casing cover 120.

The casing body 110 may have a hollow cylindrical shape with open at one side. The closed side of the casing body 110 may be disposed to face the rear of the cylinder 13. The casing body 110 may be fixed to the rear of the cylinder 13 by various types of coupling methods such as bolting, welding, and fitting. The casing body 110 is not limited to having the shape illustrated in FIGS. 3 and 4, and may be designed and changed into various shapes.

The casing cover 120 may be disposed to face the casing body 110 and may close the internal space of the casing body 110. The casing cover 120 may have a substantially plate shape and may be disposed to face the open side of the casing body 110. The casing cover 120 may be fixed to the open side of the casing body 110 by various types of coupling methods such as bolting, welding, and fitting. The cross-sectional shape of the casing cover 120 may correspond to the cross-sectional shape of the casing body 110.

The first motor 200 is mounted in the casing 100 and generates rotational force to move the piston unit 20. As an example, the first motor 200 may be exemplified as various types of electric motors that may rotate a first output shaft 210 by receiving power from the outside. The first motor 200 may be fixed to the outside of the casing body 110 by various types of coupling methods such as bolting, welding, and fitting. The first output shaft 210 may protrude through the casing body 110 to the internal space thereof. The first output shaft 210 may be disposed such that the longitudinal direction thereof is parallel to the longitudinal direction of the bolt screw 22 in the cylinder 13, e.g., the X-axis direction in FIG. 3. The first motor 200 may be electrically connected to the battery or the like of the vehicle for receiving power therefrom.

The transmission gear 300 may be rotatably mounted in the casing 100. The transmission gear 300 is connected to the first motor 200 and rotated in conjunction with the rotational force generated by the first motor 200. The transmission gear 300 may function as a component that transmits the rotational force generated by the first motor 200 to the piston unit 20.

The transmission gear 300 may include a first transmission gear 310, a second transmission gear 320, and a third transmission gear 330.

The first transmission gear 310 may be connected to the first output shaft 210 of the first motor 200. As an example, the first transmission gear 310 may be a hollow helical gear or spur gear with teeth formed on the outer peripheral surface thereof. The central axis of the first transmission gear 310 may be disposed coaxially with the central axis of the first output shaft 210 of the first motor 200. The first transmission gear 310 may have an inner peripheral surface splined to the outer peripheral surface of the first output shaft 210. Accordingly, the first transmission gear 310 may be rotated at the same angular speed as the first output shaft 210 when the first motor 200 is operated.

The second transmission gear 320 may be engaged with the first transmission gear 310 and may be rotated in conjunction with the rotation of the first transmission gear 310. As an example, the second transmission gear 320 may be a hollow helical gear or spur gear with teeth formed on the outer peripheral surface thereof. The central axis of the second transmission gear 320 may be disposed parallel to the central axis of the first transmission gear 310. The second transmission gear 320 may be supported so as to be rotatable about its central axis within the casing 100 by a separate shaft (not shown) or the like. The second transmission gear 320 may have an outer peripheral surface engaged with the outer peripheral surface of the first transmission gear 310. The second transmission gear 320 may be rotated in a direction opposite to the first transmission gear 310 when the first transmission gear 310 is rotated. The second transmission gear 320 may have a larger diameter than the first transmission gear 310. Accordingly, the second transmission gear 320 may amplify the magnitude of the rotational force transmitted from the first transmission gear 310.

The third transmission gear 330 may be engaged with the second transmission gear 320 and may be rotated in conjunction with the rotation of the second transmission gear 320. The third transmission gear 330 may function as a component that finally transmits the rotational force generated by the first motor 200 to the piston unit 20. As an example, the third transmission gear 330 may be a hollow helical gear or spur gear with teeth formed on the outer peripheral surface thereof. The central axis of the third transmission gear 330 may be disposed parallel to the central axis of the second transmission gear 320. The central axis of the third transmission gear 330 may be positioned coaxially with the central axis of the bolt screw 22 of the piston unit 20. The third transmission gear 330 may have an outer peripheral surface engaged with the outer peripheral surface of the second transmission gear 320. The third transmission gear 330 may be rotated about its central axis in a direction opposite to the second transmission gear 320 when the second transmission gear 320 is rotated. The rear end of the bolt screw 22 protruding from the rear of the cylinder 13 may be inserted into the center of the third transmission gear 330. The bolt screw 22 may have an outer peripheral surface splined to the inner peripheral surface of the third transmission gear 330. Accordingly, when the third transmission gear 330 is rotated, the bolt screw 22 may rotate together with the third transmission gear 330 to move the nut screw 23 forward and backward. The third transmission gear 330 may have a larger diameter than the second transmission gear 320. Accordingly, the third transmission gear 330 may be rotated at a lower angular speed than the second transmission gear 320 when the second transmission gear 320 is rotated, and may amplify the magnitude of the rotational force transmitted to the piston unit 20.

When the first output shaft 210 is rotated in a direction of braking application, the rotational force of the first output shaft 210 may be sequentially transmitted to the first transmission gear 310, the second transmission gear 320, the third transmission gear 330, and the bolt screw 220, and the nut screw 23 and the piston 21 may move forward to bring the brake pad P into close contact with the brake disc D.

When the first output shaft 210 is rotated in a direction of braking release, the rotational force of the first output shaft 210 may be sequentially transmitted to the first transmission gear 310, the second transmission gear 320, the third transmission gear 330, and the bolt screw 220, and the nut screw 23 and the piston 21 may move backward to separate the brake pad P from the brake disc D.

The first parking member 400 may function as a component that rotates together with the transmission gear 300 and maintains parking braking force together with the second parking member 600.

FIG. 5 is a perspective view schematically illustrating the configuration of the first parking member and the second parking member according to the embodiment of the present disclosure. FIG. 6 is a front view schematically illustrating the configuration of the first parking member and the second parking member according to the embodiment of the present disclosure.

Referring to FIGS. 1 to 6, the first parking member 400 may include a first parking body 410 and an extension part 420.

The first parking body 410 may be connected to the first output shaft 210 of the first motor 200. As an example, the first parking body 410 may be in the form of a ring with a hollow formed in the center thereof. The central axis of the first parking body 410 may be positioned coaxially with the central axis of the first output shaft 210. The first parking body 410 may have an inner peripheral surface splined to the outer peripheral surface of the first output shaft 210. When the first output shaft 210 is rotated, the first parking body 410 may be rotated at the same angular speed as the first output shaft 210 and the first transmission gear 310. Accordingly, the first parking body 410 may decrease the size of the load applied to the second parking member 600, compared to when it is connected to the second transmission gear 320 or the third transmission gear 330 whose rotational force is multiplied by the gear ratio thereof. When the first output shaft 210 is rotated, the first parking body 410 may be rotated in a direction of braking application or in a direction of braking release together with the first output shaft 210.

The extension part 420 may function as a component that extends from the first parking body 410 and forms an interference structure with the second parking member 600. As an example, the extension part 420 may protrude from the circumferential surface of the first parking body 410 to the outside of the first parking body 410. The extension part 420 may consist of a plurality of extension parts. The plurality of extension parts 420 may be arranged at set intervals along the circumferential surface of the first parking body 410 around the central axis of the first parking body 410. The distance between neighboring extension parts 420 may all be the same.

Each extension part 420 may extend obliquely with respect to the radial direction of the first parking body 410. As an example, the extension part 420 may be inclined at a set angle or may extend spirally in a curved shape in a direction of braking release, namely, in a clockwise direction in FIG. 6 from the circumferential surface of the first parking body 410. Accordingly, when the extension part 420 is fastened to the second parking member 600, it may permit the first parking body 410 to rotate in the direction of braking release, and at the same time, may limit rotation of the first parking body 410 in the direction of braking release.

The second motor 500 is mounted in the casing 100 and generates rotational force to rotate the second parking member 600. As an example, the second motor 500 may be exemplified as various types of electric motors that may rotate a second output shaft 510 by receiving power from the outside. The second motor 500 may be spaced apart from the first motor 200. The second motor 500 may be disposed inside the casing body 110, or alternatively, may be disposed outside the casing body 110. The second motor 500 may be fixed to the casing body 110 by various types of coupling methods such as bolting, welding, and fitting. The second output shaft 510 may be disposed in the internal space of the casing body 110. The second output shaft 510 may be disposed such that the longitudinal direction thereof is parallel to the longitudinal direction of the first output shaft 210. Alternatively, the second output shaft 510 may be disposed such that the longitudinal direction thereof intersects the longitudinal direction of the first output shaft 210. The second motor 500 may be electrically connected to the battery or the like of the vehicle for receiving power therefrom.

The second parking member 600 may be mounted to be rotatable and linearly movable in the casing 100. The second parking member 600 may be rotated and moved linearly by the operation of the second motor 500 and may selectively limit the rotation of the first parking member 400. More specifically, the second parking member 600 may permit the first parking member 400 to rotate during normal driving of the vehicle, thereby smoothly performing main braking by the first motor 200. In addition, the second parking member 600 may limit the rotation of the first parking member 400 during main braking of the vehicle, thereby preventing the piston unit 20 from losing parking braking force by arbitrary separation from the brake pad P even if the operation of the first motor 200 is stopped.

The second parking member 600 may include a second parking body 610, a guide rail 620, and a latch 630.

The second parking body 610 may define a schematic appearance of the second parking member 600 and may support the latch 630. The second parking body 610 may be connected to the second output shaft 510 via the guide rail 620. As an example, the second parking body 610 may have a substantially rod shape.

The second parking body 610 may be rotated in a first rotation direction and a second rotation direction opposite to the first rotation direction in conjunction with the rotation of the second output shaft 510. The rotation of the second parking body 610 in the first rotation direction may mean that the second parking body 610 is rotated counterclockwise about the central axis of the second output shaft 510 in FIG. 6, and the rotation of the second parking body 610 in the second rotation direction may mean that the second parking body 610 is rotated clockwise about the central axis of the second output shaft 510 in FIG. 6.

The second parking body 610 may be moved linearly in first and second directions by the reaction force acting between the extension part 420 and the latch 630. Here, the first direction may refer to a direction that is directed toward an end, where the latch 630 is not formed, of both ends of the second parking body 610 and is parallel to the longitudinal direction of the second parking body 610. In addition, the second direction may refer to a direction opposite to the first direction, which is directed toward an end, where the latch 630 is not formed, of both ends of the second parking body 610 and is parallel to the longitudinal direction thereof.

The guide rail 620 may function as a component that transmits the rotational force of the second output shaft 510 to the second parking body 610 when the second output shaft 510 is rotated, thereby rotating the second parking body 610 in the first rotation direction or the second rotation direction. In addition, the guide rail 620 may function as a component that support the second parking body 610 to be movable in the first and second directions, thereby guiding the linear movement of the second parking body 610.

FIG. 7 is an enlarged view schematically illustrating the configuration of the guide rail according to the embodiment of the present disclosure.

Referring to FIGS. 5 to 7, the guide rail 620 may be formed through the second parking body 610. The second output shaft 510 of the second motor 500 may be inserted into the guide rail 620. The guide rail 620 may have both ends extending in the longitudinal direction of the second parking body 610. In other words, the longitudinal direction of the guide rail 620 may extend parallel to the first and second directions.

The guide rail 620 may have a width w1 that is perpendicular to the first direction and smaller than one of the widths of the second output shaft 510 perpendicular to the longitudinal direction thereof. For example, as illustrated in FIG. 7, the width w1 of the guide rail 620 perpendicular to the first direction may be smaller than the width w2 of the second output shaft 510 parallel to the first direction. Accordingly, when the second output shaft 510 is rotated, the second parking body 610 may be rotated at the same angular speed as the second output shaft 510 while the second output shaft 510 is not rotated relative to the guide rail 620. The cross-sectional shape of the second output shaft 510 may be designed and changed to various shapes except for a circular shape, such as an elliptical, polygonal, or irregular shape.

The circumferential surface of the second output shaft 510 may be slidably in contact with the inner surface of the guide rail 620. Accordingly, the second output shaft 510 may guide the second parking body 610 to move smoothly and linearly along a fixed path.

The latch 630 may extend from the second parking body 610. The latch 630 may limit or permit the rotation of the extension part 420 depending on the rotation direction of the second parking body 610.

As an example, the latch 630 may extend from one end of the second parking body 610 spaced apart from the guide rail 620 in the first direction. The longitudinal direction of the latch 630 may extend obliquely with respect to the first direction. The latch 630 may have an end directed toward the first parking member 400. The latch 630 may be inserted between any associated pair of neighboring extension parts 420 as the second parking body 610 is rotated in the first rotation direction. In this case, the latch 630 may be latched to the associated extension part 420 to limit the rotation of the first parking body 410. The latch 630 may be separated from the associated pair of neighboring extension parts 420 as the second parking body 610 is rotated in the second rotation direction. In this case, the latch 630 may be unlatched from the associated extension part 420 to permit the rotation of the first parking body 410.

The latch 630 may gradually narrow in width toward the end thereof. Accordingly, the latch 630 may be more easily inserted between any associated pair of neighboring extension parts 420 when the second parking body 610 is rotated in the first rotation direction.

When the latch 630 is inserted between the associated pair of neighboring extension parts 420, a reaction force may be generated between the latch 630 and the associated extension part 420 in a direction parallel to the first direction. This reaction force may allow the second parking body 610 to linearly move in the first direction.

The second parking member 600 may further include a first return member 640 and a second return member 650.

The first return member 640 may be connected to the second parking body 610 and may press the second parking body 610 in the second rotation direction opposite to the first rotation direction. The first return member 640 may be configured to be elastically deformable. The first return member 640 may function as a component that, when the latch 630 is unlatched from the extension part 420, rotates the second parking body 610 in the second rotation direction by its own elastic restoring force. Accordingly, when the parking braking is released, the first return member 640 may return the second parking body 610 to its initial angle without driving the second motor 500, thereby implementing the bidirectional rotation of the second parking body 610 only by ON/OFF control of the second motor 500.

As an example, the first return member 640 may be a torsion spring that stores or releases rotational force through elastic deformation. The central axis of the first return member 640 may be positioned coaxially with the central axis of the second output shaft 510. The first return member 640 may have one end connected to the second parking body 610. The first return member 640 may have the other end connected to the second motor 500. However, the connection position of the other end of the first return member 640 is not limited thereto, and various designs and changes thereof can be made. For example, the other end of the first return member 640 may be connected to the part that is fixed when the second parking body 610 rotates, for example, to the casing 100 or the like.

The first return member 640 may be mounted so as to be compressed or tensioned in the first rotation direction in a neutral state when the latch 630 is inserted into the associated pair of neighboring extension parts 420. Accordingly, when the parking braking is released, the first return member 640 may unlatch the latch 630 from the associated extension part 420 by applying rotational force to the second parking body 610 in the second rotation direction.

One end of the first return member 640 may be connected to the second parking body 610 so as to be slidable in a direction parallel to the first direction. In this case, the other end of the first return member 640 may be fixed to the second motor 500. Accordingly, the first return member 640 may apply rotational force to the second parking body 610 in the second rotation direction, and at the same time, may not interfere with the linear movement of the second parking body 610. Alternatively, one end of the first return member 640 may be fixed to the second parking body 610, and the other end of the first return member 640 may be connected to the second motor 500 so as to be slidable in a direction parallel to the first direction.

The second return member 650 may be connected to the second parking body 610 and may press the second parking body 610 in the second direction opposite to the first direction. The second return member 650 may be configured to be elastically deformable. The second return member 650 may function as a component that, when the latch 630 is unlatched from the extension part 420, linearly moves the second parking body 610 in the second direction by its own elastic restoring force. Accordingly, when the parking braking is released, the second return member 650 may return the second parking body 610, which has been moved in the first direction, to its initial position without a separate power means.

As an example, the second return member 650 may be a compression spring that is elastically deformable in the longitudinal direction thereof. The second return member 650 may be disposed such that the longitudinal direction thereof is parallel to the first direction. The second return member 650 may be inserted into the guide rail 620. The second return member 650 may have both ends that are in contact with the circumferential surface of the second output shaft 510 and the inner surface of the second parking body 610, respectively. When the second parking body 610 is moved in the first direction, the second return member 650 may be compressed longitudinally to store elastic energy. The second return member 650 may press the second parking body 610 in the second direction against the second output shaft 510 by the stored elastic energy as the latch 630 is unlatched from the extension part 420, and may move the second parking body 610 in the second direction.

The second parking member 600 may further include a support member 660.

The support member 660 may limit the range of linear movement of the second parking body 610 with respect to the first direction. More specifically, the support member 660 may function as a component that, when the second parking body 610 moves over a set distance in the first direction by the reaction force acting between the latch 630 and the extension part 420, limits the movement of the second parking body 610 by supporting the second parking body 610 in a direction opposite to the reaction force acting between the latch 630 and the extension part 420. Accordingly, the support member 660 can prevent damage to the second output shaft 510 by blocking direct transmission of the reaction force, acting between the latch 630 and the extension part 420, to the second output shaft 510.

The support member 660 may include a first stopper 661 and a second stopper 662.

The support member 660 may extend from the second parking body 610. As an example, the support member 660 may be in the form of a rod extending in a direction intersecting the first and second directions at a position where it is spaced apart from the latch 630.

The second stopper 662 may be spaced apart from the second parking body 610 and may face the first stopper 661. The second stopper 662 may come into contact with one surface of the first stopper 661 as the second parking body 610 moves over a set distance in the first direction. As an example, the second stopper 662 may be in the form of a rod extending from the inner surface of the casing 100 toward the internal space of the casing 100.

FIG. 8 is a view schematically illustrating an installation state of a restoration member according to the embodiment of the present disclosure.

Referring to FIG. 8, the first parking body 410 may be mounted to reciprocate in the longitudinal direction of the first output shaft 210. As an example, the first parking body 410 may have an inner peripheral surface splined to the outer peripheral surface of the first output shaft 210.

The side surface of the extension part 420 may be inclined with respect to the longitudinal direction of the first output shaft 210. As an example, the extension part 420 may gradually narrow in cross-sectional area as it is directed upward in FIG. 8.

The side surface of the latch 630 may be parallel to the longitudinal direction of the first output shaft 210. Alternatively, the side surface of the latch 630 may be inclined with respect to the longitudinal direction of the first output shaft 210. In this case, the side surface of the latch 630 may be formed at an angle corresponding to the side inclination of the extension part 420 so as to be in surface contact with the side surface of the extension part 420.

A portion of the reaction force acting between the extension part 420 and the latch 630 may be transmitted in a direction parallel to the longitudinal direction of the first output shaft 210 by the angle of inclination of the side surface of the extension part 420. In this case, when the reaction force acting between the extension part 420 and the latch 630 increases beyond a set magnitude, the first parking body 410 may be moved linearly in a departure direction parallel to the longitudinal direction of the first output shaft 210. When the first parking body 410 is moved in the departure direction, the extension part 420 may be separated from the latch 630. As an example, the departure direction may refer to a downward direction in FIG. 8. Accordingly, if the second parking body 610 is not rotated smoothly in the second rotation direction due to pinching between the extension part 420 and the latch 630 or damage to the first return member 640, the extension part 420 may be separated from the latch 630 by forced rotation of the first output shaft 210.

The brake actuator 30 may further include a restoration member 700.

After the first parking body 410 of the first parking member 400 is moved in the departure direction, the restoration member 700 may move the first parking body 410 in a direction opposite to the departure direction. Accordingly, the restoration member 700 may returns the first parking body 410 to its initial position after the extension part 420 and the latch 630 are forcibly separated, thereby preventing the permanent loss of the main braking maintenance performance of the brake actuator 30.

As an example, the restoration member 700 may be a compression spring that is elastically deformable in the longitudinal direction thereof. The restoration member 700 may be disposed such that the longitudinal direction thereof is parallel to the longitudinal direction of the first output shaft 210. The central axis of the restoration member 700 may be positioned coaxially with the central axis of the first output shaft 210. The restoration member 700 may have both ends that are in contact with the upper surface of the first parking body 410 and the lower surface of the first transmission gear 310, respectively. Alternatively, first and second ends of the restoration member 700 may be in contact with the lower surface of the first parking body 410 and the upper surface of the first motor 200, respectively.

When the first parking body 410 is located at its initial position, the restoration member 700 may be mounted in an untensioned or uncompressed neutral state. When the first parking body 410 is moved in the departure direction, the restoration member 700 may be tensioned or compressed longitudinally to accumulate elastic energy. After the extension part 420 and the latch 630 are forcibly separated, the restoration member 700 may press or pull the first parking body 410 in a direction opposite to the departure direction by the accumulated elastic energy to return the first parking body 410 to its initial position. The initial position of the first parking body 410 may be designed and changed in various ways within the range of the position where the latch 630 is insertable between the associated pair of neighboring extension parts 420 when the second parking body 610 is rotated in the first rotation direction.

Although it has been described above as an example that the first parking body 410 is mounted to reciprocate in the longitudinal direction of the first output shaft 210, the present disclosure is not limited thereto. For example, the second parking body 610 may also be mounted to reciprocate in the longitudinal direction of the second output shaft 510.

In this case, the restoration member 700 may be disposed such that the longitudinal direction thereof is parallel to the longitudinal direction of the second output shaft 510, and may have both ends that are in contact with the second parking body 610 and the second motor 500 or the second parking body 610 and the casing 100, respectively.

The brake actuator 30 may further include a control module.

The control module is connected to the first motor 200 and the second motor 500, and controls the operation of the first motor 200 and the second motor 500. More specifically, the control module may control the operation of the first motor 200 and the second motor 500 based on the braking signal or brake release signal generated by a driver's brake pedal operation or a parking braking command. The control module may be implemented as an integrated circuit (IC), a microcontroller (μC), a microprocessor, an application specific integrated circuit (ASIC), or a combination thereof, which may be electrically connected to the first motor 200 and the second motor 500 and may control whether the first output shaft 210 and the second output shaft 510 rotate, the rotation speeds of the first output shaft 210 and second output shaft 510, and the like. The control module may control the directions of rotation of the first output shaft 210 and the second output shaft 510 only in one direction through ON/OFF operation. Alternatively, the control module may bidirectionally control the directions of rotation of the first output shaft 210 and the second output shaft 510 through multiple circuits. The control module may be disposed inside the casing 100, or otherwise may be coupled to the outer surface of the casing 100.

Hereinafter, the operation of the brake actuator 30 according to the embodiment of the present disclosure will be described.

FIGS. 9 to 11 are views schematically illustrating a process of generating parking braking force.

Referring to FIGS. 1 to 11, during parking braking, in a state in which the second parking body 610 is located at its initial position, the first motor 200 may rotate the first output shaft 210 in a direction of braking application (in a counterclockwise direction in FIG. 9).

As the first output shaft 210 is rotated in the direction of braking application, the rotational force of the first output shaft 210 may be transmitted to the piston unit 20 through the transmission gear 300 and the brake pad P may come into contact with the brake disc D to generate braking force in the vehicle.

In this case, the first parking member 400 may be rotated in the direction of braking application together with the first output shaft 210.

The second motor 500 may then rotate the second output shaft 510 in a first rotation direction (in a counterclockwise direction in FIG. 10).

As the second output shaft 510 is rotated in the first rotation direction, the second parking body 610 is rotated in the first rotation direction together with the second output shaft 510 and the latch 630 is moved toward the first parking member 400.

As the second parking body 610 is rotated at more than a set angle in the first rotation direction, the latch 630 may be inserted between any associated pair of neighboring extension parts 420.

The first return member 640 may be elastically deformed as the second parking body 610 is rotated in the first rotation direction, thereby accumulating elastic energy to rotate the second parking body 610 in the second rotation direction.

Then, the operation of the first motor 200 is stopped, and a rotational force is generated in the first output shaft 210 in a direction of braking release (in a clockwise direction in FIG. 11) by the reaction force acting between the brake disc D and the brake pad P.

The extension part 420 and the latch 630 are unlatched from each other by the rotational force applied to the first output shaft 210 in the direction of braking release, and a reaction force is generated in the first direction between the extension part 420 and the latch 630.

The second parking body 610 is moved linearly in the first direction (in the right direction in FIG. 11) by the reaction force acting between the extension part 420 and the latch 630.

As the second parking body 610 is moved linearly over a set distance in the first direction, the first stopper 661 comes into contact with the second stopper 662 and the movement of the second parking body 610 in the first direction is stopped.

The reaction force acting between the extension part 420 and the latch 630 is offset by the first stopper 661 and the second stopper 662. Accordingly, the size of the load transmitted to the second output shaft 510 may be decreased by the latching between the extension part 420 and the latch 630.

As the second parking body 610 is moved linearly in the first direction, the first return member 640 may be elastically deformed in a direction parallel to the first direction, thereby accumulating elastic energy to linearly move the second parking body 610 in the second direction.

Then, the rotational force applied to the first output shaft 210 in the direction of braking release may be offset by the latching force between the extension part 420 and the latch 630 and the supporting force of the second stopper 662 with respect to the first stopper 661, and the parking braking may be maintained by limiting the rotation of the first parking body 410 and the first output shaft 210.

FIGS. 12 to 14 are views schematically illustrating a process of releasing parking braking force.

Referring to FIGS. 1 to 14, when the parking braking is released, in the state of FIG. 11, the first motor 200 may rotate the first output shaft 210 at a certain angle in a direction of braking application (in a counterclockwise direction in FIG. 12).

As the first output shaft 210 is rotated in the direction of braking application, the magnitude of the reaction force acting between the extension part 420 and the latch 630 is decreased.

Due to this reduction in reaction force, the second parking body 610 may be rotated in a second rotation direction (in a clockwise direction in FIG. 13) and may be moved linearly in a second direction (in a left direction in FIG. 13) by the elastic energy accumulated due to the elastic deformation of the first return member 640 and the second return member 650.

As the second parking body 610 is rotated in the rotation direction and moved linearly in the second direction, the latch 630 is separated from the pair of neighboring extension parts 420 and the rotation of the first parking body 410 and the first output shaft 210 is permitted.

Then, the first output shaft 210 may be rotated in the direction of braking release (in the clockwise direction in FIG. 14), thereby releasing the parking braking force.

FIGS. 15 and 16 are views schematically illustrating a process of forcibly releasing parking braking force.

Referring to FIGS. 1 to 16, if the first output shaft 210 is not rotated in the direction of braking application (in the counterclockwise direction in FIG. 14) and the second parking body 610 is not rotated in the second rotation direction (in the clockwise direction in FIG. 14) due to pinching between the extension part 420 and the latch 630 or damage to the first return member 640, the first motor 200 forcibly rotates the first output shaft 210 in the direction of braking release (in the clockwise direction in FIG. 14).

As the first output shaft 210 is rotated in the direction of braking release, the magnitude of the reaction force acting between the extension part 420 and the latch 630 is increased.

A portion of the reaction force acting between the extension part 420 and the latch 630 is transmitted in a direction parallel to the longitudinal direction of the first output shaft 210 by the angle of inclination of the side surface of the extension part 420.

When the reaction force acting between the extension part 420 and the latch 630 increases beyond a set magnitude, the first parking body 410 is moved linearly in a departure direction (in a downward direction in FIG. 16) parallel to the longitudinal direction of the first output shaft 210.

The extension part 420 may be moved relative to the latch 630 in the longitudinal direction of the first output shaft 210, and the extension part 420 and the latch 630 may be separated from each other.

In this process, the restoration member 700 is elastically deformed in the longitudinal direction of the first output shaft 210 to accumulate elastic energy to restore the first parking body 410 to its initial position.

As the extension part 420 and the latch 630 are separated from each other, the first output shaft 210 may be rotated in the direction of braking release.

Then, when the second parking body 610 is returned to its initial position by the elastic restoring force of the first return member 640, the driving force of the second motor 500, or manually, the first parking body 410 may be moved in a direction opposite to the departure direction (in an upward direction in FIG. 16) and may be returned to its initial position.

While the present disclosure has been described with respect to the embodiments illustrated in the drawings, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It will be understood by those skilled in the art that various modifications and other equivalent embodiments may be made without departing from the spirit and scope of the disclosure as defined in the following claims.

Therefore, the technical protection scope of the present disclosure should be defined by the following claims.

BRAKE ACTUATOR AND BRAKE APPARATUS INCLUDING THE SAME

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CPC

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Priority Claims (1)