Vehicle brake system

Abstract

Disclosed is a vehicle brake system including: a caliper body including a cylinder; a piston portion movably disposed on the cylinder and arranged to face a brake pad; a nut screw portion arranged inside the piston portion and rotated by receiving a rotational force from an actuator; a bolt screw portion including a bolt body coupled to the nut screw portion and receiving a rotational force from the nut screw portion, and a bolt head provided separately from the bolt body, coupled to the bolt body, and arranged to face the piston portion; and a bearing portion including an outer ring portion in contact with an inner surface of the cylinder, and bearing balls arranged between the outer ring portion and the nut screw portion. According to the present disclosure, since the bolt head is manufactured as a product separate from the bolt body, shape flexibility of the bolt head can be improved.

Description

Technical Field

[0001] Exemplary embodiments of this disclosure relate to vehicle braking systems, and more particularly, to vehicle braking systems capable of ensuring stable braking performance. Background Technology

[0002] Typically, vehicle braking systems utilize driving force to push pistons to bring brake pads into contact with brake discs, and use the friction between the brake pads and brake discs to brake the vehicle. In vehicle braking systems, electromechanical brakes (EMBs) generate braking force without the use of hydraulic pressure by mounting an electric motor-driven actuator on the caliper to pressurize the piston via a mechanism. In this mechanism, the electric motor-driven actuator converts the rotational motion of a screw into the linear motion of a nut, or vice versa.

[0003] The EMB system can perform active and independent braking on each wheel, enabling not only general main movement but also additional functions such as anti-lock braking system (ABS), electronic stability control (ESC), traction control system (TCS), and automatic emergency braking (AEB), and achieving higher performance because there is no delay in hydraulic delivery.

[0004] According to relevant technologies, using thrust bearings in ball screws increases the axial length of the caliper body, resulting in disadvantages in component configuration and space efficiency. Furthermore, conventional four-point ball bearings suffer from large ball size and a limited number of balls, leading to an increased outer diameter within the caliper and complicating assembly. Moreover, in conventional designs, when the spindle travels beyond its maximum permissible stroke, this operation becomes uncontrollable, potentially causing malfunction or failure of the EMB (Electronic Brake Module).

[0005] The background technology of this disclosure is disclosed in Korean Patent Publication No. 10-2024-0054695 (published on April 26, 2024, entitled "Braking Device for Vehicles"). Utility Model Content

[0006] The purpose of this disclosure is to provide a vehicle braking system that at least partially solves some of the problems described above.

[0007] Various implementations relate to vehicle braking systems, in which the bolt body and bolt head of the bolt shank are manufactured separately.

[0008] Various implementations relate to vehicle braking systems, in which the contact diameter between the bolt head and the piston portion can be enlarged.

[0009] Various implementations relate to vehicle braking systems capable of stably supporting the nut and screw portion during the generation and release of braking force.

[0010] Various implementations relate to vehicle braking systems capable of reducing the outer diameter of components such as bolt and nut bolt portions.

[0011] Various implementations relate to vehicle braking systems that can prevent malfunctions or failures by setting the maximum permissible travel of the bolt thread portion.

[0012] A vehicle braking system according to a first embodiment of the present disclosure may include: a caliper body including a cylinder; a piston portion movably disposed on the cylinder and arranged to face the brake pad; a nut and screw portion disposed inside the piston portion and rotated by receiving rotational force from an actuator; a bolt and screw portion including a bolt body and a bolt head, the bolt body being coupled to the nut and screw portion and receiving rotational force from the nut and screw portion, the bolt head being separately disposed from the bolt body, coupled to the bolt body, and arranged to face the piston portion; and a bearing portion including an outer ring portion and bearing balls, the outer ring portion contacting the inner surface of the cylinder, the bearing balls being disposed between the outer ring portion and the nut and screw portion.

[0013] The outer ring portion may include: a bearing ball contact portion on which bearing balls are placed; an outer ring bottom portion which is connected to a first side of the bearing ball contact portion and has the same height as the area of ​​the bearing ball contact portion that contacts the outermost region of the bearing ball; and an outer ring step portion which is connected to a second side of the bearing ball contact portion and protrudes further toward the nut and screw portion than the outer ring bottom portion.

[0014] The bottom of the outer ring can protrude toward the nut screw to be positioned further inward than the outermost area of ​​the bearing balls.

[0015] The nut screw portion may include: a rolling contact portion on which bearing balls are mounted; a nut bottom portion connected to a first side of the rolling contact portion; and a nut step portion connected to a second side of the rolling contact portion and protruding further toward the outer ring portion than the nut bottom portion.

[0016] The bottom of the nut can protrude towards the outer ring to be positioned further outward than the innermost area of ​​the bearing balls.

[0017] The bearing ball contact portion may include a first outer contact area and a second outer contact area. The first outer contact area is arranged on one side of the outer ring step portion relative to the outermost region of the bearing ball, and the second outer contact area is arranged on one side of the bottom of the outer ring. The rolling contact portion may include a first inner contact area and a second inner contact area. The first inner contact area is arranged on one side of the nut step portion relative to the innermost region of the bearing ball, and the second inner contact area is arranged on one side of the bottom of the nut.

[0018] The first outer contact area and the first inner contact area can be arranged such that the bearing balls face each other diagonally, and the bearing balls can be supported by contacting the first outer contact area and the first inner contact area when the bolt thread portion moves toward the piston portion.

[0019] The second outer contact area and the second inner contact area can be arranged so that the bearing balls face each other diagonally, and the bearing balls can be supported by contacting the second outer contact area and the second inner contact area when the bolt thread portion moves toward the opposite side of the piston portion.

[0020] The bolt head may include: a head connection portion coupled to the bolt body and having a diameter larger than the outer diameter of the bolt body; and a head expansion portion extending from the head connection portion toward the piston portion and having an outer diameter larger than the outer diameter of the head connection portion.

[0021] The head extension may have a curved surface region surrounding the periphery of the piston portion, and the head extension may roll contact with the piston portion on the curved surface region.

[0022] A vehicle braking system according to a second embodiment of this disclosure may include: a caliper body including a cylinder; a piston portion movably disposed on the cylinder and arranged facing the brake pad; a nut and screw portion disposed inside the piston portion, rotating by receiving rotational force from an actuator, and including an outer ball track forming a circulation path for ball members on its inner peripheral surface; and a bolt and screw portion including a bolt body and a bolt head, the bolt body being coupled to and receiving rotational force from the nut and screw portion, the bolt head being separately disposed from the bolt body, coupled to the bolt body, and arranged facing the piston portion, wherein an inner ball track is disposed on the outer peripheral surface of the bolt body facing the outer ball track and forming a circulation path for ball members. The nut and screw portion may include a first return hole unit, a return channel, and a second return hole unit, the ball members entering and exiting through the first return hole unit, the return channel communicating with the first return hole unit, the second return hole unit communicating with the return channel, and the ball members entering and exiting through the second return hole unit.

[0023] The ball bearings entering the first return hole unit can be guided to the second return hole unit through the return channel, and the ball bearings entering the second return hole unit can be guided to the first return hole unit through the return channel.

[0024] The first return hole unit can be arranged closer to the piston than the second return hole unit.

[0025] The vehicle braking system may also include a bearing portion and bearing balls, the bearing portion having an outer ring portion that contacts the inner surface of the cylinder, the bearing balls being arranged between the outer ring portion and the nut and screw portion.

[0026] The outer ring portion may include: a bearing ball contact portion on which bearing balls are placed; an outer ring bottom portion connected to a first side of the bearing ball contact portion; and an outer ring step portion connected to a second side of the bearing ball contact portion and protruding further toward the nut and screw portion than the outer ring bottom portion.

[0027] The nut screw portion may include: a rolling contact portion on which bearing balls are mounted; a nut bottom portion connected to a first side of the rolling contact portion and having the same height as the portion of the bearing ball contact portion that contacts the innermost area of ​​the bearing balls; and a nut step portion connected to the other side of the rolling contact portion and protruding further toward the second ring portion than the nut bottom portion.

[0028] The outer ring step and the nut step can be arranged to face each other diagonally relative to the bearing balls.

[0029] The bolt head may include a head connection portion and a head extension portion. The head connection portion is coupled to the bolt body and has a diameter larger than the outer diameter of the bolt body. The head extension portion extends from the head connection portion toward the piston portion and has an outer diameter larger than the outer diameter of the head connection portion.

[0030] The head extension may have a curved surface region surrounding the periphery of the piston portion, and the head extension may contact the piston portion on the curved surface region.

[0031] When the piston section is tilted relative to the central axis, the head extension section can roll relative to the piston section in the curved surface area, and the nut screw section can roll relative to the bearing section.

[0032] A vehicle braking system according to a third embodiment of the present disclosure may include: a caliper body including a cylinder; a piston portion movably disposed on the cylinder and arranged to face the brake pad; a nut screw portion disposed inside the piston portion and rotated by receiving rotational force from an actuator; and a bolt screw portion including a bolt body and a bolt head, the bolt body being coupled to the nut screw portion to receive rotational force from the nut screw portion, the bolt head being separately disposed from the bolt body to be coupled to the bolt body and arranged to face the piston portion, wherein the nut screw portion blocks the movement toward the piston portion when the bolt body moves toward the piston portion by a predetermined distance.

[0033] The bolt body may be provided with a stop protrusion, and the stop member is provided on the inner circumferential surface of the nut thread portion. When the stop protrusion contacts the stop member, it can prevent the bolt body from moving inside the nut thread portion.

[0034] The stop protrusion can protrude further outward than the outer circumferential surface of the bolt body, and the stop can protrude further inward than the inner circumferential surface of the nut shank.

[0035] The stop protrusion can be press-fitted or bolted to the bolt body for integration, and the stop can be press-fitted or bolted to the nut shank for integration.

[0036] The outer diameter of the bolt head can be larger than the outer diameter of the bolt body.

[0037] The bolt head may include a head connection portion and a head extension portion, the head connection portion being coupled to the bolt body, and the head extension portion extending from the head connection portion toward the piston portion and having an outer diameter larger than the outer diameter of the head connection portion.

[0038] The head extension may have a curved surface region surrounding the periphery of the piston portion, and the head extension may contact the piston portion on the curved surface region.

[0039] When the piston section is tilted relative to the central axis, the head extension section can roll relative to the piston section on the curved surface area.

[0040] The vehicle braking system may also include a bearing portion disposed between the cylinder and the nut and screw portion and supporting the nut and screw portion, such that the nut and screw portion rotates within the cylinder and can roll relative to the bearing portion when the piston portion is tilted relative to the central axis.

[0041] The bearing portion may include an outer ring portion and bearing balls. The outer ring portion contacts the inner surface of the cylinder. The bearing balls are arranged between the outer ring portion and the nut and screw portion. The nut and screw portion may include a rolling contact portion at the part facing the bearing balls.

[0042] According to this disclosure, since the bolt head is manufactured as a product separate from the bolt body, the shape flexibility of the bolt head can be improved.

[0043] According to this disclosure, as the contact diameter of the bolt head that contacts the piston increases, the load can be stably transmitted to the piston.

[0044] According to this disclosure, when braking force is generated and released, the bearing balls contact the rolling contact portion and the bearing ball contact portion, thereby stably supporting the load of the nut screw portion.

[0045] According to this disclosure, since the bearing portion is configured as a two-point bearing, assembly is simple and the ball size can be reduced, thereby enabling a reduction in the outer diameter of the bolt thread portion and nut thread portion assembly.

[0046] According to this disclosure, since the return path is separately provided in the nut screw section, the ball component can repeatedly cycle and run on the outer ball track and the inner ball track, thereby stably converting and transmitting the rotational torque to the axial load.

[0047] According to this disclosure, since the maximum permissible stroke of the bolt thread is set by the stop protrusion and the stop member, it is possible to prevent malfunctions or failures of the vehicle braking system in advance. Attached Figure Description

[0048] Figure 1 This is a perspective view schematically showing a vehicle braking system according to a first embodiment of the present disclosure.

[0049] Figure 2 This is a schematic cross-sectional view of a vehicle braking system according to a first embodiment of the present disclosure.

[0050] Figure 3 yes Figure 2 A magnified view of a portion of the image.

[0051] Figure 4 yes Figure 3 A magnified view of a portion of the image.

[0052] Figure 5 This is an enlarged view showing the bearing portion of a vehicle braking system according to a first embodiment of the present disclosure.

[0053] Figure 6 This is a perspective view showing the actuator section of a vehicle braking system according to a first embodiment of the present disclosure.

[0054] Figure 7 This is a schematic cross-sectional view of a vehicle braking system according to a second embodiment of the present disclosure.

[0055] Figure 8This is a schematic view showing the return path of a ball bearing in a vehicle braking system according to a second embodiment of the present disclosure.

[0056] Figure 9 yes Figure 7 A magnified view of a portion of the image.

[0057] Figure 10 yes Figure 9 A magnified view of a portion of the image.

[0058] Figure 11 This is a schematic cross-sectional view of a vehicle braking system according to a third embodiment of the present disclosure.

[0059] Figure 12 This is a cross-sectional view showing the nut and bolt portions of a vehicle braking system according to a third embodiment of the present disclosure.

[0060] Figure 13 This is a cross-sectional perspective view showing the nut and bolt portions of a vehicle braking system according to a third embodiment of the present disclosure.

[0061] Figure 14 yes Figure 11 A magnified view of a portion of the image.

[0062] Figure 15 yes Figure 14 A magnified view of a portion of the image. Detailed Implementation

[0063] In the following, a vehicle braking system according to the present disclosure will be described in detail with reference to the accompanying drawings through various exemplary embodiments. It should be understood that, for clarity and convenience of description, the thickness of each line or the size of each component in the drawings may be exaggerated. Furthermore, the terms described below have been defined by consideration of their function in this disclosure and may vary depending on the intent or practice of the user or operator. Therefore, these terms should be interpreted based on the entire contents of this specification.

[0064] Figure 1 This is a perspective view schematically showing a vehicle braking system according to a first embodiment of the present disclosure. Figure 2 This is a schematic cross-sectional view of a vehicle braking system according to a first embodiment of the present disclosure. Figure 3 yes Figure 2 A magnified view of a portion of the image. Figure 4 yes Figure 3 A magnified view of a portion of the image. Figure 5 This is an enlarged view showing the bearing portion of a vehicle braking system according to a first embodiment of the present disclosure, and Figure 6 This is a perspective view showing the actuator section of a vehicle braking system according to a first embodiment of the present disclosure.

[0065] refer to Figures 1 to 6 The vehicle braking system according to the embodiments of the present disclosure includes a caliper body 100, a piston portion 200, a nut and screw portion 300, and a bolt and screw portion 400.

[0066] The caliper body 100 forms the external shape of the vehicle braking system and surrounds or supports the piston portion 200, the nut and screw portion 300, and the bolt and screw portion 400. The caliper body 100 includes a bridging member 110, a finger member 120, and a cylinder 130.

[0067] The bridging member 110 forms the appearance of the central portion of the caliper body 100 and supports the finger member 120 and the cylinder 130. The bridging member 110 can be connected to a bracket (not shown) via a guide rod (not shown), which is fixed to the steering knuckle (not shown), etc.

[0068] The lower surface of the bridging member 110 is positioned at predetermined intervals facing the circumferential surface of the brake disc 20. The two sides of the bridging member 110 are positioned relative to the brake disc 20 along a first direction (e.g., Figure 2 The +X direction shown) and the second direction opposite to the first direction (as shown) Figure 2 Extends in the -X direction (as shown).

[0069] A pair of brake pads 30 are arranged below the bridging member 110. The pair of brake pads 30 are arranged facing each other, and the brake disc 20 is located between the pair of brake pads 30.

[0070] Friction pads, including those made of materials with a high coefficient of friction (such as rubber), can be attached to the side of each brake pad 30 facing the brake disc 20.

[0071] Finger 120 extends downward from the first side of bridging member 110. Finger 120 is arranged to face one of a pair of brake pads 30.

[0072] Cylinder 130 extends downward from the second side of bridge 110. Cylinder 130 may have a hollow cylindrical shape. One side of cylinder 130 ( Figure 2 The left side of the pair of brake pads 30 is arranged to face the other one of the pair of brake pads 30.

[0073] One side of the cylinder 130 is open, and the open side of the cylinder 130 is spaced apart from the brake pad 30 by a certain distance, which is spaced apart from the brake disc 20 in the second direction.

[0074] The central axis of cylinder 130 is parallel to the central axis C1 of brake disc 20. The central axis of cylinder 130 is in a third direction (based on...) Figure 2 It is spaced apart from the central axis C1 of the brake disc 20 in the +Z direction.

[0075] The third direction can be exemplified as a direction perpendicular to the first and second directions and extending from the central axis C1 of the brake disc 20 toward the central axis of the cylinder 130.

[0076] When the lower surface of the bridging component 110 is parallel to the ground, the third direction can be a direction perpendicular to the ground, i.e., based on... Figure 2 The direction of upward movement along the Z-axis.

[0077] Piston 200 is arranged in cylinder 130 in a first direction (based on Figure 2 (in the +X direction) or the second direction (based on) Figure 2 It is movable in the -X direction. The piston part 200 is arranged inside the cylinder 130.

[0078] The piston portion 200 has a hollow, cylindrical shape. The sides of the piston portion 200 facing the brake pad 30 can be closed. The piston portion 200 can be arranged along the longitudinal direction of the cylinder 130.

[0079] The outer surface of the piston portion 200 is slidably supported on the inner surface of the cylinder 130. Alternatively, the outer surface of the piston portion 200 may be spaced apart from the inner surface of the cylinder 130 by a set distance.

[0080] When the piston 200 moves in the first direction, it protrudes outward from the cylinder 130 and presses the brake pad 30, which is positioned facing the cylinder 130, toward the brake disc 20. As a result, the vehicle braking system generates braking force.

[0081] When the piston portion 200 moves in the second direction, the piston portion 200 separates from the brake pad 30. Therefore, the pressure applied to the brake pad 30 by the piston portion 200 is released, and the braking force of the vehicle braking system disappears.

[0082] The piston section 200 includes a piston body 210 and a piston head 220.

[0083] The piston body 210 has a hollow cylindrical shape, and the piston head 220 is connected to the piston body 210 to close one side of the piston body 210. Figure 2 (Left side of the piston body 210). The piston head 220 is arranged on one of the open sides of the piston body 210, so as to face the brake pad 30 to close the open area of ​​the piston body 210.

[0084] The bolt shank portion 400 is arranged inside the piston portion 200. The bolt body 410 and bolt head 420 of the bolt shank portion 400 are surrounded by the piston body 210. The bolt head 420 is arranged to be inserted into the piston head 220.

[0085] A piston boot 260, which prevents external foreign matter from entering and provides a water-tight seal inside the cylinder 130, is installed inside the cylinder 130. The piston boot 260 is installed between the cylinder 130 and the piston section 200. The piston boot 260 is coupled to the piston body 210 or the piston head 220 and press-fitted into the cylinder 130.

[0086] The piston cover 260 is arranged to surround the piston portion 200. The piston cover 260 comprises an elastically deformable material. For example, the piston cover 260 may comprise a rubber material. The piston cover 260 may have a corrugated shape.

[0087] The nut screw portion 300 is rotatably arranged in the cylinder 130 and coupled to the bolt screw portion 400. A bearing portion 500 that rotatably supports the nut screw portion 300 is installed inside the cylinder 130. The bearing portion 500 may be a ball bearing arranged between the cylinder 130 and the nut screw portion 300.

[0088] The nut and screw portion 300 has a hollow cylindrical shape with open ends. The nut and screw portion 300 is arranged inside the cylinder 130, and the central axis of the nut and screw portion 300 can be positioned on the same axis as the central axis of the cylinder 130.

[0089] The first side of the nut and screw section 300 (based on) Figure 2 The left side) is set at an interval facing the inner side of the piston part 200 (based on) Figure 2 (Right side). The second side of the nut and screw section 300 (based on) Figure 2 (The right side) passes through cylinder 130 and protrudes outside cylinder 130.

[0090] The nut threaded portion 300 is arranged such that its inner surface faces the outer surface of the bolt threaded portion 400. An outer ball track R1, on which the spherical ball bearing member B is mounted, is arranged on the inner circumferential surface of the nut threaded portion 300. The outer ball track R1 extends in a helical shape in the longitudinal direction of the nut threaded portion 300. The outer ball track R1 of the nut threaded portion 300, together with the inner ball track R2 of the bolt threaded portion 400 on the other side, forms the circulation path of the ball bearing member B.

[0091] When the actuator 600 is running, the nut screw part 300 receives the rotational force generated from the actuator 600 through the power transmission part and rotates clockwise or counterclockwise around the central axis.

[0092] The nut screw portion 300 includes a nut screw body 310 and a nut screw tail portion 320.

[0093] Most of the nut and screw body 310 is located inside the cylinder 130, while all or most of the nut and screw tail 320 is exposed outside the cylinder 130. The nut and screw body 310 is surrounded by the piston body 210.

[0094] The nut screw tail 320 has a non-circular cylindrical shape. A non-circular shape refers to a shape that is not perfectly circular and includes shapes such as ellipses and polygons. In this embodiment, the nut screw tail 320 has a polygonal cylindrical shape, specifically, a generally hexagonal cylindrical shape.

[0095] The bolt thread portion 400 and the nut thread portion 300 are rotationally interlocked to allow movement within the cylinder 130 in a first and second direction. The bolt thread portion 400 is disposed inside the nut thread portion 300. The bolt thread portion 400 may be arranged to pass through both ends of the nut thread portion 300.

[0096] The bolt thread portion 400 moves in a first direction to move the piston portion 200 to pressurize the brake pad 30, the first direction being toward the brake pad 30. Furthermore, when the bolt thread portion 400 moves in a second direction opposite to the first direction, the pressure on the piston portion 200 can be released.

[0097] The bolt shank portion 400 includes a bolt body 410 and a bolt head 420.

[0098] The bolt body 410 is coupled to the nut shank portion 300 to receive rotational force from the nut shank portion 300. The bolt head 420 is separately disposed from the bolt body 410. The bolt body 410 is press-fitted into the bolt head 420 for integration. For example, the bolt body 410 may be serrated and press-fitted into the bolt head 420.

[0099] Because the bolt head 420 is separately disposed from the bolt body 410, the shape flexibility of the bolt head 420 can be improved. In particular, the shape of the bolt head 420 can be changed according to the specifications of the vehicle braking system, and because the bolt head 420 is separately disposed from the bolt body 410, it is relatively easy to standardize, easy to customize, and can increase design freedom. According to this embodiment, when the size of the piston portion 200 is changed, the contact diameter of the bolt head 420 can be easily changed accordingly.

[0100] The bolt body 410 is rotationally interlocked with the nut shank 300, and when the bolt body 410 translates in the first direction inside the cylinder 130, it is positioned in front of the bolt body 410. Figure 2 The bolt head 420 on the left side presses against the piston part 200.

[0101] The bolt body 410 has a cylindrical shape with a generally circular cross-section. The bolt body 410 is arranged inside the cylinder 130, and the central axis of the bolt body 410 is located on the same axis as the central axis of the cylinder 130. The bolt body 410 is coupled to the nut shank portion 300 via a ball bearing member B.

[0102] An inner ball track R2, on which the ball bearing component B is mounted, is arranged on the outer peripheral surface of the bolt body 410. The inner ball track R2 is located in the longitudinal direction of the bolt body 410 (based on...). Figure 2 The ball bearing extends in a spiral shape in the left-right direction to provide a circulation path for the ball bearing component B. Therefore, when the nut screw portion 300 rotates, the bolt body 410 can move in the first or second direction through the circulatory movement of the ball bearing component B.

[0103] The outer ball track R1, arranged on the inner circumferential surface of the nut thread portion 300, and the inner ball track R2, arranged on the outer circumferential surface of the bolt body 410, are arranged to face each other. The ball member B may have an exterior guided by the outer ball track R1 and an interior guided by the inner ball track R2, so as to move in a helical shape along the outer ball track R1 and the inner ball track R2.

[0104] A bolt head 420 is disposed between the bolt body 410 and the piston portion 200. The bolt head 420 may have a generally circular cross-section. The bolt head 420 is arranged to insert into the piston head 220. The bolt head 420 is arranged to face the inner surface of the piston head 220 at a predetermined interval. When no braking force is generated or when braking force is released in the vehicle braking system, the bolt head 420 may be arranged to be spaced apart from the piston head 220.

[0105] Bolt head 420 can press piston head 220. Depending on the direction of movement of bolt body 410, bolt head 420 can press piston head 220 or release pressure on piston head 220 in a first direction.

[0106] The outer diameter of the bolt head 420 can be larger than the outer diameter of the bolt body 410. Therefore, when the bolt shank portion 400 presses against the piston portion 200 to move toward the brake pad 30, the contact diameter of the bolt shank portion 400 that contacts the piston portion 200 can be increased.

[0107] Compared to when the outer diameter of the bolt head 420 contacting the piston head 220 is equal to or smaller than the outer diameter of the bolt body 410, when the outer diameter of the bolt head 420 is larger than the outer diameter of the bolt body 410, the contact diameter of the bolt head 420 with the piston head 220 is further increased. Therefore, the efficiency of load transmission to the piston portion 200 through the bolt head 420 can be improved. Furthermore, as the contact diameter of the bolt head 420 with the piston head 220 increases, the load can be stably transmitted to the piston portion 200, and the bolt screw portion 400 can be stably kept in the center.

[0108] The bolt head 420 includes a head connection portion 421 and a head extension portion 422.

[0109] The head connection portion 421 is the portion that faces the bolt body 410 from the bolt head 420 and is coupled to the bolt body 410. The head extension portion 422 extends from the head connection portion 421 toward the piston head 210 and has an outer diameter larger than the outer diameter of the head connection portion 421. Therefore, the contact diameter between the bolt shank portion 400 and the piston portion 200 can be increased.

[0110] Compared to when the outer diameter of the head extension 422 contacting the piston head 220 is equal to the outer diameter of the head connection 421, when the outer diameter of the head extension 422 is larger than the outer diameter of the head connection 421, the contact diameter of the head extension 422 contacting the piston head 220 is further increased. Therefore, the efficiency of load transmission to the piston portion 200 through the bolt head 420 can be improved. Furthermore, as the contact diameter of the head extension 422 contacting the piston head 220 increases, load transmission to the piston portion 200 becomes more stable.

[0111] The head extension 422 has a curved surface region 422a on its outer periphery facing the piston head 220. The curved surface region 422a is a convex curved surface region facing the piston head 220 and is arranged on the entire outer periphery of the head extension 422. The head extension 422 can contact the piston head 220 on the curved surface region 422a.

[0112] The head extension 422 can roll in contact with the piston head 220 on the curved surface region 422a. That is, the head extension 422 can roll relative to the piston head 220 on the curved surface region 422a.

[0113] The piston head 220 includes a flat surface region 220a in the area that contacts the curved surface region 422a. Therefore, when the head extension 422 contacts the piston head 220 due to the movement of the bolt thread portion 400 in the first direction, even if the head extension 422 rolls relative to the piston head 220, the head extension 422 including the convex curved surface region 422a and the piston head 220 including the flat surface region 220a can remain in contact with each other.

[0114] When the brake disc 20 rubs against the brake pad 30 and generates braking force through the movement of the piston 200, the shape of the caliper body 100 may be partially deformed due to the reaction force. Therefore, compared to the non-braking state, the cylinder 130 and piston 200 may be slightly tilted relative to the central axis. That is, in the braking state, the cylinder 130 and / or piston 200 may be tilted at a small angle relative to their respective central axes.

[0115] When the cylinder 130 and / or the piston portion 200 tilts about their respective central axes, the head extension 422 can roll in contact with the piston head 220 on the curved surface region 422a. That is, when the cylinder 130 and / or the piston portion 200 tilts about their respective central axes, the head extension 422 can roll relative to the piston head 220 on the curved surface region 422a.

[0116] When the cylinder 130 and / or piston 200 tilt about their respective central axes, the head extension 422 rolls relative to the piston head 220, so the bolt body 410 coupled to the bolt head 420 also tilts at an angle as large as the angle at which the bolt head 420 tilts by the rolling motion.

[0117] In this way, when the cylinder 130 and / or piston 200 tilt relative to their respective central axes, the bolt head 420 and bolt body 410 also tilt, thereby preventing the load from being concentrated only on a specific ball member B among the plurality of ball members B arranged in the longitudinal direction of the bolt body 410. Therefore, the robustness of the bolt shank portion 400 when the cylinder 130 and / or piston portion 200 tilts can be ensured, thereby improving the durability of the vehicle braking system.

[0118] The bearing portion 500 is arranged between the cylinder 130 and the nut and screw portion 300 and supports the nut and screw portion 300, so that the nut and screw portion 300 can rotate within the cylinder 130.

[0119] When the cylinder 130 and / or piston 200 tilt about their respective central axes, the nut screw portion 300 can roll into contact with the bearing portion 500. That is, when the cylinder 130 and / or piston 200 tilt about their respective central axes, the nut screw portion 300 can roll relative to the bearing portion 500.

[0120] In this way, when the cylinder 130 and / or piston 200 tilt relative to their respective central axes, the nut screw portion 300 also tilts, preventing the load on the nut screw portion 300 from being concentrated only on a specific ball member B among the plurality of ball members B arranged in the longitudinal direction along the bolt body 410. Therefore, the robustness of the bolt screw portion 400 when the cylinder 130 and / or piston portion 200 tilts can be ensured, thereby improving the durability of the vehicle braking system.

[0121] The bearing section 500 includes an outer ring section 510 and bearing balls 520.

[0122] The outer ring portion 510 contacts the inner surface of the cylinder 130. The outer ring portion 510 is press-fitted into the cylinder 130 (e.g., mounting protrusion 135) and securely fixed in place. Because the outer ring portion 510 is press-fitted into the cylinder 130, the load applied to the bearing ball 520 can be distributed in the axial direction and / or the outer radial direction through the outer ring portion 510.

[0123] Bearing balls 520 are arranged between the outer ring portion 510 and the nut and screw body 310. In this embodiment, since the nut and screw body 310 acts as the inner ring portion of the bearing portion 500, the outer diameter of the bearing portion 500 can be reduced, thereby enabling a more compact manufacturing of the vehicle braking system and reducing the number of components, thus lowering costs.

[0124] The outer ring portion 510 includes a bearing ball contact portion 515, an outer ring step portion 516, and an outer ring bottom portion 517.

[0125] The outer ring portion 510 includes: an outer ring bottom 517 formed on the piston head 220 side relative to the bearing ball contact portion 515; and an outer ring step portion 516 formed on the nut screw tail portion 320 side. Compared to the outer ring bottom 517, the outer ring step portion 516 protrudes more inward toward the nut screw portion 300, and the bearing ball contact portion 515 is arranged between the outer ring step portion 516 and the outer ring bottom 516.

[0126] The bearing ball contact portion 515 is formed with a concave curved surface area facing inward and is arranged on the entire inner circumference of the outer ring portion 510. The bearing ball 520 is in direct contact with the bearing ball contact portion 515, or indirect contact with the bearing ball contact portion 515 through another component. In this embodiment, the bearing ball 520 is placed on the bearing ball contact portion 515.

[0127] The bearing ball 520 arranged between the outer ring portion 510 and the nut screw body 310 has an outermost region 520A and an innermost region 520B. On the outer peripheral surface of the bearing ball 520, the outermost region 520A is farthest from the center of the bolt screw portion 400, and on the outer peripheral surface of the bearing ball 520, the innermost region 520B is closest to the center of the bolt screw portion 40.

[0128] The outer ring step portion 516 and the outer ring bottom portion 517 protrude toward the nut screw portion 300, so as to be located inwards from the outermost region 520A of the bearing ball 520. Therefore, the outer ring step portion 516 and the outer ring bottom portion 517 are arranged to surround the outermost region 520A of the bearing ball 520.

[0129] The bearing ball contact portion 515 includes a first outer contact area 515A and a second outer contact area 515B. The first outer contact area 515A is disposed on the outer ring step portion 516 side relative to the outermost region 520A of the bearing ball 520, and the second outer contact area 515B is disposed on the outer ring bottom 517 side relative to the outermost region 520A of the bearing ball 520. The bearing ball 520 can contact the inner surface of the bearing ball contact portion 515 at the first outer contact area 515A and the second outer contact area 515B.

[0130] The nut screw body 310 includes a rolling contact portion 315, a nut step portion 316, and a nut bottom portion 317.

[0131] Since the nut screw body 310 functions as an inner ring portion, which is the rotating portion of the bearing portion 500, the nut screw body 310 rotates relative to the outer ring portion 510. Furthermore, since the nut screw body 310 has a rolling contact portion 315 in the area facing the bearing ball 520, the nut screw body 310 can roll relative to the bearing ball 520. Moreover, because the nut screw body 310 rolls relative to the bearing ball 520, the angle between the nut screw body 310 and the outer ring portion 510 can be changed.

[0132] The nut screw body 310 has a nut step portion 316 disposed on the piston head 220 side relative to the rolling contact portion 315 and a nut bottom portion 317 disposed on the nut screw tail portion 320 side. Compared with the nut bottom portion 317, the nut step portion 316 protrudes further outward toward the outer ring portion 510, and the rolling contact portion 315 is disposed between the nut step portion 316 and the nut bottom portion 317.

[0133] The rolling contact portion 315 is arranged with a concave curved surface portion facing inward and is arranged on the entire outer periphery of the nut screw body 310. The bearing ball 520 is in direct contact with the rolling contact portion 315 or indirect contact with the rolling contact portion 315 through another component.

[0134] Because the rolling contact portion 315 has a curved surface, the nut screw body 310 rolls relative to the bearing balls 520 or the outer ring portion 510 on the rolling contact portion 315.

[0135] The nut step portion 316 and the nut bottom portion 317 may protrude further outward than the innermost region 520B of the bearing ball 520. Therefore, the nut step portion 316 and the nut bottom portion 317 may be arranged to surround the innermost region 520B of the bearing ball 520.

[0136] The rolling contact portion 315 includes a first inner contact area 315A and a second inner contact area 315B. The first inner contact area 315A is arranged on the side of the nut step portion 316 relative to the innermost area 520B of the bearing ball 520, and the second inner contact area 315B is arranged on the side of the nut bottom portion 317 relative to the innermost area 520B of the bearing ball 520. The bearing ball 520 contacts the inner surface of the rolling contact portion 315 in the first inner contact area 315A and the second inner contact area 315B.

[0137] The nut screw portion 300 rotates in one direction to generate braking force in the vehicle braking system, and thus the bolt screw portion 400 moves toward the piston portion 200. During the generation of braking force in the vehicle braking system, the bearing balls 520 contact the first inner contact area 315A and the first outer contact area 515A of the rolling contact portion 315 to stably support the load applied by the nut screw portion 300 in a direction opposite to the direction of movement of the bolt screw portion 400. The first inner contact area 315A and the first outer contact area 515A are arranged to face each other in a diagonal direction relative to the bearing balls 520.

[0138] When the braking force of the vehicle braking system is released, the nut screw portion 300 rotates in the opposite direction, and thus the bolt screw portion 400 moves toward the opposite side of the piston portion 200. During the release of the braking force of the vehicle braking system, the bearing balls 520 contact the second inner contact area 315B and the second outer contact area 515B of the rolling contact portion 315, and the bearing balls 520 can stably support the load applied to the nut screw portion 300 in the direction opposite to the movement direction of the bolt screw portion 400. Furthermore, even when the nut screw portion 300 rotates, displacement in the front-rear direction can be suppressed, and zero drag can be implemented when separated from the piston portion 200. The second inner contact area 315B and the second outer contact area 515B are arranged to face each other in a diagonal direction relative to the bearing balls 520.

[0139] During braking of the vehicle braking system, the piston portion 200 or the cylinder 130 can tilt relative to the central axis by means of braking torque or the opening of the caliper body 100. According to this embodiment, since the bolt head 420 rolls relative to the piston portion 200, it prevents the load from being concentrated only on a specific ball member B among the plurality of ball members B arranged on the outer surface of the bolt thread portion 400. Furthermore, according to this embodiment, since the nut thread portion 300 moves relative to the bearing portion 500 in a rolling motion, it prevents the load from being concentrated only on a specific ball member B among the plurality of ball members B arranged on the inner surface of the nut thread portion 300.

[0140] The vehicle braking system according to this embodiment can move in a rolling motion in front of the bolt thread portion 400, outside the nut thread portion 300, or in the portion in front of the bolt thread portion 400 and outside the nut thread portion 300, so that even when the piston portion 200 is tilted relative to the central axis or the cylinder 130 is tilted relative to the central axis, the concentrated load received by the specific ball member B can be suppressed. Therefore, the vehicle braking system according to this embodiment can improve the durability of the device while ensuring robustness against tilting.

[0141] The vehicle braking system according to an embodiment of the present disclosure also includes an actuator section 600.

[0142] The actuator section 600 receives power from the motor section 660 to provide rotational force to the nut and screw section 300.

[0143] The actuator section 600 includes a power transmission section. The power transmission section can engage with the nut screw section 300 to transmit rotational force to the nut screw section 300. When the nut screw section 300 rotates under the rotational force provided by the actuator section 600, the bolt screw section 400 can translate.

[0144] This embodiment provides a nut-screw driven vehicle braking system, wherein the nut-screw portion 300 first rotates by receiving rotational force from the actuator portion 600, and then the nut-screw portion 300 and the bolt-screw portion 400, which are dynamically coupled by the ball member B, rotate continuously. Therefore, according to this embodiment, the axial length can be reduced compared to a bolt-screw driven vehicle braking system.

[0145] The power transmission unit may include multiple gears that are sequentially engaged and coupled between the motor unit 660 and the nut and screw unit 300. The power transmission unit is not limited to this configuration, and the design can be modified to accommodate various types of power transmission devices capable of rotating the nut and screw unit 300 by receiving rotational force from the motor unit 660.

[0146] The power transmission unit includes a power transmission channel 620 arranged inside the actuator housing 610.

[0147] The power transmission groove 620 is arranged around the anti-rotation protrusion 630, and the nut screw tail 320 of the nut screw portion 300 can be inserted therein.

[0148] The power transmission groove 620 is arranged in a shape corresponding to the tail portion 320 of the nut screw, and engages with the tail portion 320 of the nut screw. The power transmission groove 620 may be formed as a non-circular groove. A non-circular shape refers to a shape other than a perfect circle, and includes shapes such as ellipses and polygons. In this embodiment, the power transmission groove 620 is formed as a polygonal groove, specifically, a generally hexagonal groove.

[0149] Since each of the nut screw tail portion 320 and the power transmission groove 620 has a non-circular shape but the same or corresponding shape, when the nut screw tail portion 320 is inserted into the power transmission groove 620, the nut screw tail portion 320 and the power transmission groove 620 engage with each other. Therefore, when the power transmission groove 620 rotates during the operation of the actuator section 600, the nut screw tail portion 320, which engages with the power transmission groove 620, also rotates in the same direction. Therefore, the rotational force of the actuator section 600 can be stably transmitted to the nut screw portion 300 without loss.

[0150] The actuator section 600 may include an anti-rotation section. The anti-rotation section can limit the rotation of the bolt thread section 400 by engaging with the bolt thread section 400. When the nut thread section 300 rotates under the rotational force provided by the actuator section 600, the bolt thread section 400 translates.

[0151] Since the nut screw portion 300 and the bolt screw portion 400 are dynamically coupled through the ball bearing member B, the rotation of the bolt screw portion 400 is prevented by the anti-rotation part, thereby converting the rotation of the nut screw portion 300 into the translation of the bolt screw portion 400.

[0152] The anti-rotation part includes an anti-rotation protrusion 630. The anti-rotation protrusion 630 is disposed inside the actuator housing 610 and protrudes to the outside of the actuator housing 610. The anti-rotation protrusion 630 is disposed inside the power transmission groove 620.

[0153] When the nut spur tail 320 is inserted into the power transmission groove 620 and engages with it, the anti-rotation protrusion 630 is inserted into the anti-rotation groove 411 of the bolt body 410 and engages with it. In this way, according to this embodiment, power transmission to the nut spur portion 300 and anti-rotation of the bolt spur portion 400 can be achieved with a single component, and therefore, assemblability can be greatly improved.

[0154] The anti-rotation protrusion 630 may be non-circular columnar. Non-circular means not perfectly circular and includes shapes such as ellipses or polygons. In this embodiment, the anti-rotation protrusion 630 is polygonal columnar, specifically, generally hexagonal columnar.

[0155] The anti-rotation groove 411 is arranged in the bolt body 410 in a shape corresponding to the anti-rotation protrusion 630 to engage with the anti-rotation protrusion 630. The anti-rotation groove 411 may be formed as a non-circular groove. A non-circular shape refers to a shape other than a perfect circle, including shapes such as ellipses or polygons. In this embodiment, the anti-rotation groove 411 is formed as a polygonal groove, specifically, a generally hexagonal groove.

[0156] Since each of the anti-rotation protrusion 630 and the anti-rotation groove 411 has a non-circular shape but the same or corresponding shape, the anti-rotation protrusion 630 and the anti-rotation groove 411 engage with each other when the anti-rotation protrusion 630 is inserted into the anti-rotation groove 411. Therefore, when the power transmission groove 620 rotates during the operation of the actuator section 600, the nut screw tail 320, which engages with the power transmission groove 620, rotates in the same direction, but the rotation of the bolt body 410 is prevented. Therefore, the rotational force of the actuator section 600 can be stably converted into the translational motion of the bolt screw section 400 without loss.

[0157] The anti-rotation protrusion 630 and the anti-rotation groove 411 are in surface contact with each other, thereby reducing the loss of friction and keeping the bolt body 410 centered when an axial positive load is generated. In addition, since the anti-rotation groove 411 can be integrally formed with the bolt body 410, there is no need to manufacture the anti-rotation structure separately, and space utilization can be increased.

[0158] The anti-rotation groove 411 includes an outwardly extending inclined surface 411a to induce insertion of the anti-rotation protrusion 630. The anti-rotation protrusion 630 includes an inclined surface region 630a that tapers outward at its front end for easier insertion into the anti-rotation groove 411.

[0159] The length of the anti-rotation protrusion 630 inserted into the bolt body 410 can be greater than the maximum stroke of the piston portion 200. The maximum stroke of the piston portion 200 refers to the distance the piston portion 200 moves from the origin to the maximum forward stroke, and the stroke of the piston portion 200 can increase due to wear as the brake pad 30 wears. Therefore, since the length of the anti-rotation protrusion 630 inserted into the bolt body 410 is greater than the maximum stroke of the piston portion 200, the anti-rotation protrusion 630 always engages with the anti-rotation groove 411 of the bolt body 410 and can continuously prevent the bolt thread portion 400 from rotating.

[0160] Figure 7 This is a schematic cross-sectional view of a vehicle braking system according to a second embodiment of the present disclosure. Figure 8 This is a schematic view illustrating the return path of the ball bearing in a vehicle braking system according to a second embodiment of the present disclosure. Figure 9 yes Figure 7 A magnified view of a portion of the image, and Figure 10 yes Figure 9 A magnified view of a portion of the image.

[0161] refer to Figures 7 to 10 as well as Figure 1 and Figure 6 The vehicle braking system according to the second embodiment of this disclosure includes a caliper body 100, a piston portion 200, a nut and screw portion 300, and a bolt and screw portion 400. The vehicle braking system according to the second embodiment of this disclosure differs from [the previous one] only in certain configurations. Figures 1 to 6 The vehicle braking system in the first embodiment differs from that in the following text, therefore, details regarding the braking system are omitted. Figures 1 to 6 The first embodiment of the vehicle braking system is described with the same configuration.

[0162] The caliper body 100 includes a bridging component 110, a finger component 120, and a cylinder 130.

[0163] The piston section 200 includes a piston body 210 and a piston head 220.

[0164] The nut and screw section 300 includes a nut and screw body 310 and a nut and screw tail section 320.

[0165] The outer ball track R1, which is arranged on the inner circumferential surface of the nut shank portion 300, and the inner ball track R2, which is formed on the outer circumferential surface of the bolt body 410, are arranged to face each other. Each ball component B has an outer portion guided by the outer ball track R1 and an inner portion guided by the inner ball track R2, so as to move in a helical shape along the outer ball track R1 and the inner ball track R2.

[0166] The nut screw portion 300 includes a return path that moves the ball members B on a first side of the outer ball track R1 and the inner ball track R2 to a second side of the outer ball track R1 and the inner ball track R2. The return path of the nut screw portion 300 includes a first return hole unit 350, a return channel 353, and a second return hole unit 355.

[0167] The first return hole unit 350 has an inner diameter larger than the outer diameter of each ball member B, allowing the ball members B running on the outer ball track R1 and the inner ball track R2 to enter and exit. The first return hole unit 350 is arranged to communicate with the outer ball track R1 and the inner ball track R2, allowing the ball members B to enter or exit.

[0168] The second return hole unit 355 has an inner diameter larger than the outer diameter of the ball member B, allowing the ball member B, which runs on the outer ball track R1 and the inner ball track R2, to enter and exit. The second return hole unit 355 is arranged to communicate with the outer ball track R1 and the inner ball track R2, allowing the ball member B to enter or exit. The second return hole unit 355 is formed at a different point than the first return hole unit 350. In this embodiment, the first return hole unit 350 may be arranged closer to the piston portion 200 than the second return hole unit 355.

[0169] One side of the return channel 353 communicates with the first return hole unit 350, and the other side communicates with the second return hole unit 355, connecting the first return hole unit 350 and the second return hole unit 355. Therefore, the ball component B entering the first return hole unit 350 is guided through the return channel 353 to the second return hole unit 355, and then advances again onto the outer ball track R1 and the inner ball track R2. The ball component B entering the second return hole unit 355 is guided through the return channel 353 to the first return hole unit 350, and then advances again onto the outer ball track R1 and the inner ball track R2.

[0170] The first return hole unit 350 and the second return hole unit 355 allow the ball member B to enter and exit. For example, during the generation of braking force in the vehicle braking system, i.e., when the bolt screw portion 400 moves toward the piston portion 200, the ball member B can enter the first return hole unit 350 and exit from the second return hole unit 355. Conversely, when the braking force is released from the vehicle braking system, i.e., when the bolt screw portion 400 moves to the opposite side of the piston portion 200, the ball member B can enter the second return hole unit 355 and exit from the first return hole unit 350.

[0171] Based on the process of generating braking force in a vehicle braking system, when the bolt screw portion 400 moves towards the piston portion 200 through the rotation of the nut screw portion 300 and reaches the set point where the first return hole unit 350 is arranged in this embodiment, the ball component B enters the first return hole unit 350 side through the continuous rotation of the nut screw portion 300. Thereafter, the ball component B is guided to the second return hole unit 355 through the return channel 353, leaves from the second return hole unit 355, and is again arranged on the outer ball track R1 and the inner ball track R2. As the rotation of the nut screw portion 300 continues, the ball component B travels from the point where the second return hole unit 355 is arranged along the outer ball track R1 and the inner ball track R2, reaches the point where the first return hole unit 350 is arranged, and then re-enters the first return hole unit 350. Therefore, the recirculation of the ball component B can continue.

[0172] Based on the process of releasing the braking force of the vehicle braking system, when the bolt screw portion 400 moves to the opposite side of the piston portion 200 due to the rotation of the nut screw portion 300 and the ball component B reaches the point where the second return hole unit 355 is arranged, the ball component B enters the second return hole unit 355 through the continuous rotation of the nut screw portion 300. Thereafter, the ball component B is guided to the first return hole unit 350 through the return channel 353, leaves the first return hole unit 350, and is re-arranged on the outer ball track R1 and the inner ball track R2. As the rotation of the nut screw portion 300 continues, the ball component B travels from the point where the first return hole unit 350 is arranged along the outer ball track R1 and the inner ball track R2, reaches the point where the second return hole unit 355 is arranged, and then re-enters the second return hole unit 355. Therefore, the recirculation of the ball component B can continue.

[0173] According to this embodiment, since the return path is separately provided in the nut screw portion 300, the ball component B can repeatedly cycle and run on the outer ball track R1 and the inner ball track R2. Therefore, the durability between the nut screw portion 300 and the bolt screw portion 400 can be improved, and during braking or release operations of the vehicle braking system, the rotational torque can be stably transferred to the shaft and transmitted.

[0174] The bolt shank portion 400 includes a bolt body 410 and a bolt head 420, and the bolt head 420 includes a head connection portion 421 and a head extension portion 422.

[0175] The bearing portion 500 includes an outer ring portion 510 and bearing balls 520. The outer ring portion 510 includes a bearing ball contact portion 515, an outer ring step portion 516, and an outer ring bottom portion 517.

[0176] The outer ring portion 510 includes an outer ring bottom 517 formed on the piston head 220 side relative to the bearing ball contact portion 515 and an outer ring step portion 516 formed on the nut screw tail portion 320 side. The outer ring step portion 516 protrudes further inward into the nut screw portion 300 than the outer ring bottom 517, and the bearing ball contact portion 515 is arranged between the outer ring step portion 516 and the outer ring bottom 517.

[0177] The bearing ball contact portion 515 has an inwardly recessed curved surface area and is arranged on the entire inner circumference of the outer ring portion 510. The bearing ball 520 is in direct contact with the bearing ball contact portion 515, or indirect contact with the bearing ball contact portion 515 through another component. In this embodiment, the bearing ball 520 can be mounted on the bearing ball contact portion 515.

[0178] The bearing balls 520 arranged between the outer ring portion 510 and the nut screw body 310 include an outermost region 520A and an innermost region 520B. The outermost region 520A is the region of the outer peripheral surface of the bearing balls 520 that is farthest from the center of the bolt screw portion 400, and the innermost region 520B is the region of the outer peripheral surface of the bearing balls 520 that is closest to the center of the bolt screw portion 400.

[0179] The bottom of the outer ring 517 has the same height as the outermost region 520A of the bearing ball contact portion 515 that contacts the outermost region 520A of the bearing ball 520.

[0180] The bearing ball contact portion 515 may include an outer contact area 515A. The outer contact area 515A is closer to the outer wheel step portion 516 than the outer ring bottom 517, relative to the outermost region 520A of the bearing ball 520. The bearing ball 520 may contact the inner surface of the bearing ball contact portion 515 at the outer contact area 515A.

[0181] The bearing portion 500 also includes a bearing cover 511. A first side of the bearing cover 511 is press-fitted to the inner surface of the outer ring portion 510, and a second side of the bearing cover 511 extends toward the nut body 310. The bearing cover 511 is positioned in front of the nut step portion 316, thus restricting the movement of the nut screw body 310 beyond a predetermined range. In other words, because the bearing cover 511 is spaced a predetermined distance from the front of the nut step portion 316, further movement of the nut step portion 314 may be blocked by the bearing cover 511 when the nut screw body 310 moves relative to the outer ring portion 510 by a predetermined range. Therefore, relative movement between the nut screw portion 300 and the cylinder 130 can be prevented from exceeding the predetermined range.

[0182] The nut and screw body 310 includes a rolling contact portion 315, a nut step portion 316, and a nut bottom 317. The rolling contact portion 315 is formed as a curved surface region recessed inward and is arranged on the entire outer periphery of the nut and screw body 310. The bearing ball 520 can directly contact the rolling contact portion 315 or indirectly contact the rolling contact portion 315 through another component. In this embodiment, the bearing ball 510 can be placed on the ball contact portion 315.

[0183] Because the rolling contact portion 315 has a curved portion, the nut screw body 310 can roll relative to the bearing balls 520 or the outer ring portion 510 on the rolling contact portion 315.

[0184] The nut step 316 protrudes further outward than the innermost region 520B of the bearing ball 520. Therefore, the nut step 316 is arranged to surround the innermost region 520B of the bearing ball 520. The nut bottom 317 has the same height as the area where the rolling contact portion 315 contacts either the innermost region 520B or the outermost region 520A of the bearing ball 520.

[0185] The rolling contact portion 315 includes an inner contact area 315A. The inner contact area 315A is closer to the nut step portion 316 than the bottom of the nut 317, relative to the innermost region 520B of the bearing ball 520. The bearing ball 520 can contact the inner surface of the rolling contact portion 315 at the inner contact area 315A.

[0186] The nut screw portion 300 rotates in one direction to generate braking force in the vehicle braking system, and thus the bolt screw portion 400 moves toward the piston portion 200. During the generation of braking force in the vehicle braking system, the bearing balls 520 contact the inner contact area 315A and the outer contact area 515A of the rolling contact portion 315 to stably support the load applied by the nut screw portion 300 in the direction opposite to the movement direction of the bolt screw portion 400.

[0187] According to this embodiment, when the braking force of the vehicle braking system is generated or released, the bearing balls 520 of the bearing portion 500 can be configured as a two-point bearing that contacts the inner contact area 315A of the rolling contact portion 315 and the outer contact area 515A of the bearing ball contact portion 515. Compared with a four-point bearing, the two-point bearing is easier to assemble and the ball size can be reduced, thus reducing the outer diameter of the assembly of the bolt thread portion 400 and the nut thread portion 300.

[0188] During braking of the vehicle braking system, the piston portion 200 can tilt relative to the central axis by the braking torque or the opening of the caliper body 100, or the cylinder 130 can tilt relative to the central axis. According to this embodiment, since the bolt head 420 can roll relative to the piston portion 200, it is possible to prevent the load from being concentrated only on a specific ball member B among the plurality of ball members B arranged on the outer surface of the bolt thread portion 400. Furthermore, according to this embodiment, since the nut thread portion 300 can roll relative to the bearing portion 500, it is possible to prevent the load from being concentrated only on a specific ball member B among the plurality of ball members B arranged on the inner surface of the nut thread portion 300.

[0189] Since the vehicle braking system according to this embodiment can roll in front of the bolt thread portion 400, outside the nut thread portion 300, or in front of the bolt thread portion 400 and outside the nut thread portion 300, even when the piston portion 200 is tilted relative to the central axis or the cylinder 130 is tilted relative to the central axis, the concentrated load received by the specific ball member B can be suppressed. Therefore, the vehicle braking system according to this embodiment can improve the durability of the system while ensuring robustness against tilting.

[0190] Figure 11 This is a schematic cross-sectional view of a vehicle braking system according to a third embodiment of the present disclosure. Figure 12 This is a cross-sectional view showing the nut and bolt portions of a vehicle braking system according to a third embodiment of the present disclosure. Figure 13 This is a cross-sectional perspective view showing the nut and bolt portions of a vehicle braking system according to a third embodiment of the present disclosure. Figure 14 yes Figure 11 A magnified view of a portion of the image, and Figure 15 yes Figure 14 A magnified view of a portion of the image.

[0191] refer to Figures 11 to 15 as well as Figure 1 and Figure 6The vehicle braking system according to the third embodiment of this disclosure includes a caliper body 100, a piston portion 200, a nut and screw portion 300, and a bolt and screw portion 400. The vehicle braking system according to the third embodiment of this disclosure differs from [the previous one] only in certain configurations. Figure 1 The vehicle braking system of the first embodiment differs from that in the following text; therefore, details regarding the difference are omitted. Figure 1 The first embodiment of the vehicle braking system is described with the same configuration.

[0192] The caliper body 100 includes a bridging component 110, a finger component 120, and a cylinder 130.

[0193] The piston section 200 includes a piston body 210 and a piston head 220.

[0194] The nut screw portion 300 includes a nut screw body 310 and a nut screw tail portion 320.

[0195] The track hole and through hole 325 can be provided on the inner circumferential surface of the nut screw portion 300. In the track hole, the outer ball track R1 on which the ball member B is mounted is arranged in a spiral shape in the longitudinal direction. The through hole 325 is the inner circumferential surface of the nut screw portion 300 where the outer ball track R1 is not arranged.

[0196] The through-hole portion 325 is arranged along the inner circumferential surface of the nut shank tail portion 320. The inner diameter of the through-hole portion 325 is larger than the maximum outer diameter of the bolt body 410. Therefore, the bolt body 410 can move within the through-hole portion 325 during rotation of the nut shank portion 300.

[0197] A stop 326 is provided in the through hole 325. The stop 326 can be formed during the machining of the inner circumferential surface of the nut thread portion 300. The stop 326 is arranged separately from the nut thread portion 300, and the stop 326 can be press-fitted or bolted to the nut thread portion 300 to be integrated with the nut thread portion 300.

[0198] The stop 326 protrudes inward from the inner circumferential surface of the through hole 325 and is arranged on the movement path of the stop protrusion 416. When the bolt body 410 moves toward the piston 200 by the rotation of the nut screw portion 300, the stop protrusion 416 provided at the end of the bolt body 410 also moves in the same direction. Since the stop 326 is arranged on the movement path of the stop protrusion 416, when the bolt body 410 moves a set distance, the stop protrusion 416 is blocked by the stop 326 and cannot move further. The set distance that the bolt body 410 can move can be within the maximum permissible travel range set in the vehicle braking system.

[0199] The maximum permissible travel of the bolt thread section 400 can be set differently depending on the thickness of the brake pad 30 required by the caliper. The bolt thread section 400 can move further in the first direction, depending on the wear of the brake pad 30, and the zero setting value can be reset in the state of further movement.

[0200] When the bolt body 410 moves a set distance toward the piston portion 200, the nut screw portion 300 prevents the bolt body 410 from moving toward the piston portion 200. According to another embodiment, when the bolt screw portion 400 reaches its maximum permissible stroke, the stop protrusion 416 of the bolt screw portion 400 contacts the stop member 326 of the nut screw portion 300, and thus prevents the bolt screw portion 400 from moving in the first direction.

[0201] The maximum distance that the bolt body 410 can move within the nut thread portion 300 can be the maximum permissible stroke of the bolt thread portion 400. When the bolt thread portion 400 moves within the maximum permissible stroke, it can prevent malfunctions or failures of the vehicle braking system in advance.

[0202] By limiting the piston stroke of the vehicle braking system as in another embodiment of this disclosure, malfunctions or failures due to various reasons can be prevented, including manual operation difficulties when replacing the brake pad 30 due to complete wear.

[0203] The nut screw tail 320 has a non-circular cylindrical shape. A non-circular shape refers to a shape that is not perfectly circular, including shapes such as ellipses and polygons. In this embodiment, the nut screw tail 320 has a polygonal cylindrical shape, specifically, a generally hexagonal cylindrical shape.

[0204] The bolt shank portion 400 includes a bolt body 410 and a bolt head 420, and the bolt head 420 includes a head connection portion 421 and a head extension portion 422.

[0205] The bolt body 410 is provided with a stop protrusion 416, specifically, at the end opposite to the bolt head 420. The stop protrusion 416 is press-fitted or bolt-coupled to the bolt body 410 for integration with the bolt body 410. When the bolt body 410 moves a predetermined distance, the stop protrusion 416 protrudes outward beyond the outer peripheral surface of the bolt body 410 to contact the stop member 326 of the nut shank portion 300. When the stop protrusion 416 contacts the stop member 326, it prevents the bolt body 410 from moving in the first direction.

[0206] The bearing portion 500 includes an outer ring portion 510 and bearing balls 520. The outer ring portion 510 contacts the inner surface of the cylinder 130. The outer ring portion 510 is press-fitted into the cylinder 130 for secure positioning. The bearing balls 520 are arranged between the outer ring portion 510 and the nut screw body 310. In this embodiment, the nut screw body 310 is exemplified as performing the function of the inner ring portion; however, the inner ring portion may be integrally formed with the nut screw body 310 as in this embodiment, or it may be formed separately from the nut screw body 310.

[0207] The nut and screw body 310 includes a rolling contact portion 315, an upper step portion 316, and a lower bottom portion 317.

[0208] The nut screw body 310 has an upper stepped portion 316 disposed on the piston head 220 side relative to the rolling contact portion 315 and a lower bottom portion 317 disposed on the nut screw tail 320 side. The upper stepped portion 316 protrudes outward relative to the lower bottom portion 317, and the rolling contact portion 315 is disposed between the upper stepped portion 316 and the lower bottom portion 317.

[0209] The rolling contact portion 315 is formed as a curved portion that is recessed inward and is arranged on the entire outer periphery of the nut and screw body 310. The bearing ball 520 is in direct contact with the rolling contact portion 315 or indirect contact with the rolling contact portion 315 through another component.

[0210] Because the rolling contact portion 315 has a curved portion, the nut screw body 310 can roll relative to the bearing balls 520 or the outer ring portion 510 on the rolling contact portion 315.

[0211] During braking of the vehicle braking system, the piston portion 200 can tilt relative to the central axis by the braking torque or the opening of the caliper body 100, or the cylinder 130 can tilt relative to the central axis. According to this embodiment, since the bolt head 420 can roll relative to the piston portion 200, it is possible to prevent the load from being concentrated only on a specific ball member B among the plurality of ball members B arranged on the outer surface of the bolt thread portion 400. Furthermore, according to this embodiment, since the nut thread portion 300 can roll relative to the bearing portion 500, it is possible to prevent the load from being concentrated only on a specific ball member B among the plurality of ball members B arranged on the inner surface of the nut thread portion 300.

[0212] Since the vehicle braking system according to this embodiment can roll in front of the bolt thread portion 400, outside the nut thread portion 300, or in front of the bolt thread portion 400 and outside the nut thread portion 300, even when the piston portion 200 is tilted relative to the central axis or the cylinder 130 is tilted relative to the central axis, the concentrated load received by the specific ball member B can be suppressed. Therefore, the vehicle braking system according to this embodiment can improve the durability of the system while ensuring robustness against tilting.

[0213] Although this disclosure has been described with reference to embodiments shown in the accompanying drawings, the embodiments of this disclosure are for illustrative purposes only, and those skilled in the art will understand that various modifications and other equivalent embodiments may be made according to the embodiments.

Claims

1. A vehicle braking system, characterized in that, include: The caliper body includes a cylinder; A piston portion, which is movably arranged on the cylinder and positioned to face the brake pad; The nut screw section is arranged inside the piston section and rotates by receiving rotational force from the actuator; A bolt shank portion includes a bolt body and a bolt head, the bolt body being coupled to the nut shank portion and receiving the rotational force from the nut shank portion, and the bolt head being separately disposed from the bolt body, coupled to the bolt body, and arranged to face the piston portion; as well as The bearing portion includes an outer ring portion and bearing balls, the outer ring portion being in contact with the inner surface of the cylinder, and the bearing balls being arranged between the outer ring portion and the nut and screw portion.

2. The vehicle braking system according to claim 1, characterized in that, The outer ring portion includes: The bearing ball contact portion has the bearing balls mounted thereon; The bottom of the outer ring is connected to the first side of the bearing ball contact portion; and The outer ring stepped portion connects to the second side of the bearing ball contact portion and protrudes further toward the nut screw portion than the bottom of the outer ring.

3. The vehicle braking system according to claim 2, characterized in that, The bottom of the outer ring protrudes toward the nut screw portion to be positioned further inward than the outermost region of the bearing balls.

4. The vehicle braking system according to claim 3, characterized in that, The nut and screw portion includes: The rolling contact portion, on which the bearing balls are mounted; The bottom of the nut, which is connected to the first side of the rolling contact; and The nut step portion connects to the second side of the rolling contact portion and protrudes further toward the outer ring portion than the bottom of the nut.

5. The vehicle braking system according to claim 4, characterized in that, The bottom of the nut protrudes towards the outer ring to be positioned further outward than the innermost region of the bearing balls.

6. The vehicle braking system according to claim 5, characterized in that, The bearing ball contact portion includes a first outer contact area and a second outer contact area. The first outer contact area is disposed on one side of the outer ring step portion relative to the outermost region of the bearing ball, and the second outer contact area is disposed on one side of the bottom of the outer ring. The rolling contact portion includes a first inner contact area and a second inner contact area. The first inner contact area is arranged on one side of the nut step portion relative to the innermost region of the bearing ball, and the second inner contact area is arranged on one side of the bottom of the nut.

7. The vehicle braking system according to claim 6, characterized in that, The first outer contact area and the first inner contact area are arranged such that the bearing balls face each other diagonally, and the bearing balls are supported by contacting the first outer contact area and the first inner contact area while the bolt thread portion is moving toward the piston portion.

8. The vehicle braking system according to claim 6, characterized in that, The second outer contact area and the second inner contact area are arranged such that the bearing balls face each other diagonally, and the bearing balls are supported by contacting the second outer contact area and the second inner contact area while the bolt screw portion is moving toward the opposite side of the piston portion.

9. The vehicle braking system according to claim 1, wherein, The bolt head includes: A head connector, coupled to the bolt body and having a diameter larger than the outer diameter of the bolt body; and A head extension portion extends from the head connection portion toward the piston portion and has an outer diameter larger than the outer diameter of the head connection portion.

10. The vehicle braking system according to claim 9, in, The head extension has a curved surface region surrounding the periphery of the piston portion, and The head extension makes rolling contact with the piston portion on the curved surface region.

11. A vehicle braking system, comprising: The caliper body includes a cylinder; A piston portion, which is movably arranged on the cylinder and positioned to face the brake pad; The nut screw section is arranged inside the piston section, rotates by receiving rotational force from the actuator, and includes an outer ball track that forms a circulation path for the ball members on the inner circumferential surface. as well as A bolt shank portion includes a bolt body and a bolt head. The bolt body is coupled to and receives the rotational force from the nut shank portion. The bolt head is separately disposed from the bolt body, coupled to the bolt body, and arranged to face the piston portion. An inner ball track is disposed on the outer peripheral surface of the bolt body to face the outer ball track and forms a circulation path for the ball component. The nut screw portion includes a first return hole unit, a return channel, and a second return hole unit. The ball component enters and exits through the first return hole unit. The return channel is connected to the first return hole unit, and the second return hole unit is connected to the return channel. The ball component enters and exits through the second return hole unit.

12. The vehicle braking system according to claim 11, characterized in that, The ball bearing that enters the first return hole unit is guided to the second return hole unit through the return channel, and the ball bearing that enters the second return hole unit is guided to the first return hole unit through the return channel.

13. The vehicle braking system according to claim 12, characterized in that, The first return hole unit is arranged closer to the piston portion than the second return hole unit.

14. The vehicle braking system according to claim 13, characterized in that, It also includes a bearing portion and bearing balls, the bearing portion having an outer ring portion that contacts the inner surface of the cylinder, and the bearing balls being arranged between the outer ring portion and the nut screw portion.

15. The vehicle braking system according to claim 14, characterized in that, The outer ring portion includes: The bearing ball contact portion has the bearing balls mounted thereon; The bottom of the outer ring is connected to the first side of the bearing ball contact portion and has the same height as the area where the bearing ball contact portion contacts the outermost region of the bearing ball; and The outer ring stepped portion connects to the second side of the bearing ball contact portion and protrudes further toward the nut screw portion than the bottom of the outer ring.

16. A vehicle braking system, characterized in that, include: The caliper body includes a cylinder; A piston portion, which is movably arranged on the cylinder and positioned to face the brake pad; The nut screw section is arranged inside the piston section and rotates by receiving rotational force from the actuator; as well as A bolt shank portion includes: a bolt body and a bolt head, the bolt body being coupled to the nut shank portion to receive the rotational force from the nut shank portion, the bolt head being separately disposed from the bolt body, coupled to the bolt body, and arranged to face the piston portion, wherein, when the bolt body moves a predetermined distance toward the piston portion, the nut shank portion prevents movement toward the piston portion.

17. The vehicle braking system according to claim 16, characterized in that, The bolt body is provided with a stop protrusion, and the stop element is provided on the inner circumferential surface of the nut thread portion. Specifically, when the stop protrusion is in contact with the stop member, it prevents the bolt body from moving inside the nut screw portion.

18. The vehicle braking system according to claim 17, characterized in that, The stop protrusion protrudes further outward than the outer peripheral surface of the bolt body, and the stop protrudes further inward than the inner peripheral surface of the nut screw portion.

19. The vehicle braking system according to claim 17, characterized in that, The stop protrusion is press-fitted or bolted to the bolt body for integration, and The stop is press-fitted or bolted to the nut screw portion for integration.

20. The vehicle braking system according to claim 16, characterized in that, It also includes a bearing portion, which is disposed between the cylinder and the nut and screw portion and supports the nut and screw portion, allowing the nut and screw portion to rotate inside the cylinder. In this case, when the piston portion is tilted relative to the central axis, the nut screw portion rolls relative to the bearing portion.

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