Brake apparatus for vehicle

Abstract

The present invention relates to a brake device for a vehicle, comprising: a caliper body having a cylinder; a piston part movably disposed in the cylinder and disposed opposite to a brake pad; a nut screw part disposed inside the piston part, rotates by receiving rotational force from an actuator, and has an outer ball rail on its inner circumference forming a circulation path for a ball member; a bolt body coupled to the nut screw part and receiving rotational force from the nut screw part; and a bolt head provided separately from the bolt body, coupled to the bolt body, and disposed opposite to the piston part, wherein the bolt screw part has an inner ball rail on its outer circumference facing the outer ball rail to form a circulation path for a ball member; a bearing part disposed between the cylinder and the nut screw part and supporting the nut screw part so that the nut screw part can rotate inside the cylinder; and a position fixing part that contacts and supports the bearing part so that the bearing part is fixed in position on the nut screw part, wherein the nut screw part includes a first return hole part through which a ball member can be inserted and removed, and a part communicating with the first return hole part. It includes a return passage and a second return hole section that is connected to the return passage and allows a ball member to be inserted and removed.

Description

Technology Field

[0001] The present invention relates to a vehicle brake device, and more specifically, to a vehicle brake device capable of securing stable braking performance. Background Technology

[0003] Generally, a vehicle's braking system pushes a piston with driving force to bring the pad and disc into close contact, and brakes the vehicle using the frictional force between the pad and the disc.

[0004] Among vehicle braking systems, the Electro-Mechanical Brake (EMB) does not use hydraulics; instead, it mounts a motor-driven actuator on the caliper and generates braking force by pressurizing a piston through a mechanism that converts the rotational motion of a screw into the linear motion of a nut, or vice versa.

[0005] EMB enables active braking and independent braking for each wheel, allowing for the implementation of not only standard main braking but also additional functions such as ABS (Anti-lock Brake System), ESC (Electric Stability Control), TCS (Traction Control System), and AEB (Automatic Emergency Braking), and enables higher performance due to the absence of hydraulic transmission delay.

[0006] The background technology of the present invention is disclosed in Korean Published Patent Application No. 10-2024-0054695 (published April 26, 2024, Title of Invention: Brake Device for Vehicle). The problem to be solved

[0008] The present invention aims to provide a vehicle brake device in which the bolt body and bolt head of the bolt screw portion are manufactured as separate parts.

[0009] Another objective of the present invention is to provide a vehicle brake device capable of increasing the contact diameter of a bolt head in contact with a piston portion.

[0010] Another objective of the present invention is to provide a vehicle brake device capable of firmly fixing the bearing portion on the nut screw portion.

[0011] Another objective of the present invention is to provide a vehicle brake device capable of improving braking performance by limiting the displacement of the outer ring portion of the bearing portion to within a set range during the braking and release processes. means of solving the problem

[0013] A brake device for a vehicle according to one aspect of the present invention comprises: a caliper body having a cylinder; a piston portion movably disposed in the cylinder and disposed opposite to a brake pad; a nut screw portion disposed inside the piston portion, rotates by receiving rotational force from an actuator, and has an outer ball rail on its inner surface forming a circulation path for a ball member; a bolt screw portion comprising a bolt body coupled to the nut screw portion and receiving rotational force from the nut screw portion, and a bolt head disposed separately from the bolt body, coupled to the bolt body and disposed opposite to the piston portion, wherein an inner ball rail is disposed on the outer surface of the bolt body facing the outer ball rail and forming a circulation path for the ball member; and a bearing portion disposed between the cylinder and the nut screw portion and supporting the nut screw portion so that the nut screw portion can rotate inside the cylinder. and includes a position fixing part that contacts and supports the bearing part so that the bearing part is fixed in position on the nut screw part, and the nut screw part may include a first return hole part in which the ball member can be inserted and removed, a return passage communicating with the first return hole part, and a second return hole part communicating with the return passage and in which the ball member can be inserted and removed.

[0014] The ball member that has entered the first return hole section is guided to the second return hole section through the return passage, and the ball member that has entered the second return hole section can be guided to the first return hole section through the return passage.

[0015] The first return hole portion may be positioned closer to the piston portion than to the second return hole portion.

[0016] The bearing portion may include an outer ring portion that contacts the inner surface of the cylinder; an inner ring portion that is rotatable inside the outer ring portion and contacts the nut screw portion; and a bearing ball disposed between the outer ring portion and the inner ring portion.

[0017] The above position fixing part may include a contact ring part that contacts the inner ring part when coupled to the above nut screw part.

[0018] The above contact ring portion may be positioned opposite to the piston and spaced apart from the outer ring portion by a predetermined distance.

[0019] The above position fixing part may further include an extension ring part that is connected to the contact ring part, extends in the opposite direction of the piston, and makes surface contact with the nut screw part.

[0020] The above position fixing part may be made of a metal material.

[0021] The bolt head may include a head connecting portion that is coupled to the bolt body and has an outer diameter larger than the outer diameter of the bolt body; and a head extension portion that extends from the head connecting portion toward the piston portion and has an outer diameter larger than the outer diameter of the head connecting portion.

[0022] The head extension portion has a curved surface on its outer circumference facing the piston portion, and the head extension portion can come into contact with the piston portion on the curved surface. Effects of the invention

[0024] According to the present invention, the shape flexibility of the bolt head can be improved as the bolt head is manufactured separately from the bolt body.

[0025] According to the present invention, as the contact diameter of the bolt head in contact with the piston part is increased, the load can be stably transmitted to the piston part.

[0026] According to the present invention, since the position fixing part contacts and supports the inner ring part of the bearing part, the bearing part can be firmly fixed in position on the nut screw part.

[0027] According to the present invention, during the braking and release process, the position fixing part limits the displacement of the outer ring of the bearing part to within a set range, thereby improving braking performance. Brief explanation of the drawing

[0029] FIG. 1 is a perspective view showing a vehicle brake device according to one embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a vehicle brake device according to one embodiment of the present invention. FIG. 3 is a schematic diagram showing the return path of a ball member in a vehicle brake device according to one embodiment of the present invention. Figure 4 is a partial enlarged view of Figure 2. Figure 5 is a partial enlarged view of Figure 4. FIG. 6 is a drawing showing the state in which a position fixing part is mounted on a nut screw part in a vehicle brake device according to one embodiment of the present invention. FIG. 7 is a perspective view showing an actuator part of a vehicle brake device according to one embodiment of the present invention. Specific details for implementing the invention

[0030] Hereinafter, an embodiment of a vehicle brake device according to the present invention will be described with reference to the attached drawings. In this process, the thickness of lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of explanation. Furthermore, the terms described below are defined considering their functions in the present invention, and these may vary depending on the intention or convention of the user or operator. Therefore, the definitions of these terms should be based on the content throughout this specification.

[0032] FIG. 1 is a perspective view showing a vehicle brake device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view schematically showing a vehicle brake device according to an embodiment of the present invention, FIG. 3 is a diagram schematically showing the return path of a ball member in a vehicle brake device according to an embodiment of the present invention, FIG. 4 is a partial enlarged view of FIG. 2, FIG. 5 is a partial enlarged view of FIG. 4, FIG. 6 is a diagram showing the state in which a position fixing part is mounted on a nut screw part in a vehicle brake device according to an embodiment of the present invention, and FIG. 7 is a perspective view showing an actuator part of a vehicle brake device according to an embodiment of the present invention.

[0033] Referring to FIGS. 1 to 7, a vehicle brake device according to one embodiment of the present invention may include a caliper body (100), a piston part (200), a nut screw part (300), a bolt screw part (400), and a bearing part (500).

[0034] The caliper body (100) forms the outer shape of a vehicle brake device and can surround or support a piston part (200), a nut screw part (300), and a bolt screw part (400).

[0035] The caliper body (100) may include a bridge (110), a finger (120), and a cylinder (130).

[0036] The bridge (110) forms the exterior of the central part of the caliper body (100) and can support the finger (120) and the cylinder (130). The bridge (110) can be connected to a carrier (not shown) fixed to a knuckle (not shown) via a guide rod (not shown).

[0037] The lower surface of the bridge (110) may be positioned to face the periphery of the brake disc (20) at a set distance. Both sides of the bridge (110) may extend along a first direction (+X direction in FIG. 2) and a second direction (-X direction in FIG. 2), which is opposite to the first direction, respectively, with respect to the brake disc (20).

[0038] A pair of brake pads (30) may be placed on the lower side of the bridge (110). A pair of brake pads (30) may be placed facing each other with the brake disc (20) in between.

[0039] A friction pad containing a material with a high coefficient of friction, such as rubber, may be attached to one side of the brake pad (30) facing the brake disc (20).

[0040] The finger (120) may extend downward from one side of the bridge (110). The finger (120) may be positioned to face one of a pair of brake pads (30).

[0041] The cylinder (130) may extend downward from the other side of the bridge (110). The cylinder (130) may be formed in the shape of a hollow column. One side of the cylinder (130) (left side in FIG. 2) may be positioned to face the other of a pair of brake pads (30).

[0042] One side of the cylinder (130) may be open, and the open side of the cylinder (130) may be spaced apart from the brake pad (30) which is spaced apart from the brake disc (20) in a second direction by a set distance.

[0043] The central axis of the cylinder (130) may be positioned parallel to the central axis (C1) of the brake disc (20). The central axis of the cylinder (130) may be spaced apart from the central axis (C1) of the brake disc (20) along a third direction (+Z direction based on FIG. 2).

[0044] The third direction is perpendicular to the first and second directions and can be exemplified as a direction from the center axis (C1) of the brake disc (20) toward the center axis of the cylinder (130).

[0045] The third direction may be a direction perpendicular to the ground, i.e., a direction rising along the Z-axis direction with respect to FIG. 2, when the lower surface of the bridge (110) is positioned parallel to the ground.

[0046] The piston portion (200) may be positioned to be movable in a first direction (+X direction based on FIG. 2) or a second direction (-X direction based on FIG. 2) in the cylinder (130). The piston portion (200) may be positioned inside the cylinder (130).

[0047] The piston portion (200) may be formed in the shape of a column with a hollow interior. The side of the piston portion (200) facing the brake pad (30) may be closed. The piston portion (200) may be arranged along the longitudinal direction of the cylinder (130).

[0048] The outer surface of the piston portion (200) can be slidably supported on the inner surface of the cylinder (130). Alternatively, the outer surface of the piston portion (200) can be spaced apart from the inner surface of the cylinder (130) by a set distance.

[0049] As the piston portion (200) moves in the first direction, it protrudes outward from the cylinder (130) and can press the brake pad (30), which is positioned facing the cylinder (130), toward the brake disc (20). Through this, the vehicle brake device can generate braking force.

[0050] When the piston portion (200) is moved in the second direction, the piston portion (200) can be separated from the brake pad (30). As a result, the pressure applied by the piston portion (200) to the brake pad (30) is released, and the braking force of the vehicle brake device disappears.

[0051] The piston part (200) may include a piston body (210) and a piston head (220).

[0052] The piston body (210) is formed in the shape of a hollow column, and the piston head (220) is connected to the piston body (210) to close one side of the piston body (210) (left side in Fig. 2). The piston head (220) is positioned on the side facing the brake pad (30) among the open sides of the piston body (210) to close the open area of ​​the piston body (210).

[0053] A bolt screw portion (400) may be disposed on the inner side of the piston portion (200). The bolt body (410) and bolt head (420) of the bolt screw (400) are surrounded by the piston body (210). The bolt head (420) may be disposed to be inserted into the piston head (220).

[0054] A piston boot (260) may be installed on the inner side of the cylinder (130) to prevent the ingress of external foreign matter and to watertightly seal the interior of the cylinder (130). The piston boot (260) may be installed between the cylinder (130) and the piston part (200). The piston boot (260) may be coupled to the piston body (210) or the piston head (220) and pressed into the inner side of the cylinder (130).

[0055] The piston boot (260) may be formed to surround the piston portion (200). The piston boot (260) may include an elastically deformable material. For example, the piston boot (260) may be manufactured including a rubber material. The piston boot (260) may be formed to have a corrugated shape.

[0056] The nut screw portion (300) is rotatably disposed in the cylinder (130) and can be coupled with the bolt screw portion (400). A bearing portion (500) that rotatably supports the nut screw portion (300) may be installed on the inner side of the cylinder (130). The bearing portion (500) may be a ball bearing disposed between the cylinder (130) and the nut screw portion (300).

[0057] The nut screw portion (300) may be hollow inside and have a column shape with both ends open. The nut screw portion (300) is positioned inside the cylinder (130), and its central axis may be located on the same axis as the central axis of the cylinder.

[0058] One side (left side in FIG. 2) of the nut screw portion (300) may be positioned facing the inner surface (right side in FIG. 2) of the piston portion (200) at a set distance. The other side (right side in FIG. 2) of the nut screw portion (300) may penetrate the cylinder (130) and protrude to the outside of the cylinder (130).

[0059] The nut screw portion (300) may be positioned so that its inner surface faces the outer surface of the bolt screw portion (400). An outer ball rail (R1) on which a spherical ball member (B) is seated may be formed on the inner circumference of the nut screw portion (300). The outer ball rail (R1) extends in a spiral shape along the longitudinal direction of the nut screw portion (300). The outer ball rail (R1) of the nut screw portion (300) forms a circulation path for the ball member (B) together with the inner ball rail (R2) of the opposite bolt screw portion (400).

[0060] The nut screw part (300) receives rotational force generated from the actuator (600) through the power transmission part when the actuator (600) operates, and can rotate clockwise or counterclockwise around the central axis.

[0061] The nut screw part (300) may include a nut screw body (310) and a nut screw tail (320).

[0062] Most of the nut screw body (310) is positioned inside the cylinder (130), and the nut screw tail (320) may be entirely or mostly exposed outside the cylinder (130). The nut screw body (310) may be surrounded by the piston body (210).

[0063] The nut screw tail (320) may be formed in a non-circular column shape. Non-circular means a shape that is not a perfect circle, and includes shapes such as elliptical and polygonal. In this embodiment, the nut screw tail (320) is formed in a polygonal column, specifically in a roughly hexagonal column shape.

[0064] The bolt screw portion (400) can be moved in a first direction and a second direction inside the cylinder (130) in conjunction with the rotation of the nut screw portion (300). The bolt screw portion (400) can be positioned inside the nut screw portion (300). The bolt screw portion (400) can be positioned to penetrate both ends of the nut screw portion (300).

[0065] The bolt screw portion (400) can be moved in a first direction toward the brake pad (30) to move the piston portion (200) so that it presses the brake pad (30). Additionally, the bolt screw portion (400) can be moved in a second direction opposite to the first direction to release the pressure on the piston portion (200).

[0066] The bolt screw part (400) may include a bolt body (410) and a bolt head (420).

[0067] The bolt body (410) is combined with the nut screw portion (300) to receive rotational force from the nut screw portion (300). The bolt head (420) may be provided separately from the bolt body (410). The bolt body (410) may be integrated by press-fitting it into the bolt head (420). For example, the bolt body (410) may be press-fitted into the bolt head (420) in a serrated manner.

[0068] Since the bolt head (420) is manufactured separately 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) may change depending on the specifications of the vehicle brake device, etc. Since the bolt head (420) is formed separately from the bolt body (410), which is relatively easy to standardize, customization is easy and the degree of design freedom can be increased. According to the present embodiment, if the size of the piston part (200) changes, the contact diameter of the bolt head (420) can be easily changed accordingly.

[0069] When the bolt body (410) is translated into the first direction inside the cylinder (130) in conjunction with the rotation of the nut screw part (300), the bolt head (420) positioned at the front (left side according to FIG. 2) of the bolt body (410) presses the piston part (200).

[0070] The bolt body (410) may be formed in a column shape having a roughly circular cross-section. The bolt body (410) is positioned inside the cylinder (130), and its central axis may be located on the same axis as the central axis of the cylinder (130). The bolt body (410) may be joined to the nut screw portion (300) and the ball member (B) via a ball member.

[0071] An inner ball rail (R2) on which a ball member (B) is seated may be formed on the outer surface of the bolt body (410). The inner ball rail (R2) may be extended in a spiral shape along the longitudinal direction (left and right direction based on FIG. 2) of the bolt body (410) to provide a circulation path for the ball member (B). Accordingly, when the nut screw part (300) rotates, the bolt body (410) may be moved in a first direction or a second direction by the circulation movement of the ball member (B).

[0072] The outer ball rail (R1) formed on the inner circumference of the nut screw part (300) and the inner ball rail (R2) formed on the outer circumference of the bolt body (410) can be arranged to face each other. The ball member (B) can be moved in a spiral shape along the outer ball rail (R1) and the inner ball rail (R2) by having its outer part guided by the outer ball rail (R1) and its inner part guided by the inner ball rail (R2).

[0073] The nut screw section (300) may include a return path capable of moving a ball member (B) located on one side of the outer ball rail (R1) and the inner ball rail (R2) to the other side of the outer ball rail (R1) and the inner ball rail (R2). The return path of the nut screw section (300) may include a first return hole section (350), a return passage (353), and a second return hole section (355).

[0074] The first return hole section (350) may have an inner diameter larger than the outer diameter of the ball member (B) so that the ball member (B) running on the outer ball rail (R1) and the inner ball rail (R2) can enter and exit. The first return hole section (350) may be formed to be in communication with the outer ball rail (R1) and the inner ball rail (R2) so that the ball member (B) can enter or exit.

[0075] The second return hole section (355) may have an inner diameter larger than the outer diameter of the ball member (B) so that the ball member (B) operating on the outer ball rail (R1) and the inner ball rail (R2) can enter and exit. The second return hole section (355) may be formed to be in communication with the outer ball rail (R1) and the inner ball rail (R2) so that the ball member (B) can enter or exit. The second return hole section (355) is formed at a different point from the first return hole section (350). In this embodiment, the first return hole section (350) may be positioned closer to the piston section (200) than the second return hole section (355).

[0076] One side of the return passage (353) is connected to the first return hole section (350), and the other side is connected to the second return hole section (355), thereby connecting the first return hole section (350) and the second return hole section (355) to each other. Accordingly, a ball member (B) that has entered the first return hole section (350) is guided to the second return hole section (355) through the return passage (353) and can advance again onto the outer ball rail (R1) and the inner ball rail (R2), and a ball member (B) that has entered the second return hole section (355) is guided to the first return hole section (350) through the return passage (353) and can advance again onto the outer ball rail (R1) and the inner ball rail (R2).

[0077] The first return hole section (350) and the second return hole section (355) allow for both entry and exit of the ball member (B). For example, during the process in which braking force is generated in the vehicle brake device, that is, when the bolt screw section (400) moves toward the piston section (200), the ball member (B) can enter the first return hole section (350) and exit through the second return hole section (355). Conversely, during the process in which braking force is released in the vehicle brake device, that is, when the bolt screw section (400) moves toward the opposite side of the piston section (200), the ball member (B) can enter the second return hole section (355) and exit through the first return hole section (350).

[0078] When explaining the process of generating braking force in a vehicle brake device, as the bolt screw part (400) moves toward the piston part (200) by the rotation of the nut screw part (300), and the ball member (B) reaches a set point, which is the point where the first return hole part (350) is formed in this embodiment, the ball member (B) enters toward the first return hole part (350) by the continuous rotation of the nut screw part (300). Subsequently, the ball member (B) is guided to the second return hole part (355) through the return passage (353), exits from the second return hole part (355), and is placed again on the outer ball rail (R1) and the inner ball rail (R2). When the rotation of the nut screw part (300) continues, the ball member (B) travels along the outer ball rail (R1) and the inner ball rail (R2) at the point where the second return hole part (355) is formed, reaches the point where the first return hole part (350) is formed, and then recirculates the ball member (B) by entering the first return hole part (350) again.

[0079] When explaining the process of releasing braking force in a vehicle brake device, as the bolt screw part (400) moves to the opposite side of the piston part (200) by the rotation of the nut screw part (300), and the ball member (B) reaches the point where the second return hole part (355) is formed, the ball member (B) enters the second return hole part (355) side by the continuous rotation of the nut screw part (300). Subsequently, the ball member (B) is guided to the first return hole part (350) through the return passage (353), exits from the first return hole part (350), and is placed again on the outer ball rail (R1) and inner ball rail (R2). When the rotation of the nut screw part (300) continues, the ball member (B) travels along the outer ball rail (R1) and the inner ball rail (R2) at the point where the first return hole part (350) is formed, and then reaches the point where the second return hole part (355) is formed, and the recirculation of the ball member (B) can continue as it enters the second return hole part (355) again.

[0080] According to the present embodiment, since a return path is separately provided in the nut screw part (300), the ball member (B) can be repeatedly circulated and operated on the outer ball rail (R1) and the inner ball rail (R2). This improves the durability between the nut screw part (300) and the bolt screw part (400), and allows the rotational torque to be stably converted into an axial load and transmitted during braking or brake release operation of the vehicle brake device.

[0081] The bolt head (420) may be positioned between the bolt body (410) and the piston part (200). The bolt head (420) may be formed to have a roughly circular cross-section. The bolt head (420) may be positioned to be inserted into the piston head (220). The bolt head (420) may be positioned facing the inner surface of the piston head (220) at a set distance. When braking force is not generated in the vehicle brake device or when the braking force is released, the bolt head (420) may be positioned spaced apart from the piston head (220).

[0082] The bolt head (420) can press the piston head (220). The bolt head (420) can press the piston head (220) in a first direction or release the pressure according to the direction of movement of the bolt body (410).

[0083] The outer diameter of the bolt head (420) may be larger than the outer diameter of the bolt body (410). Therefore, when the bolt screw portion (400) presses the piston portion (200) to move toward the brake pad (30), the contact diameter of the bolt screw portion (400) in contact with the piston portion (200) can be increased.

[0084] When the outer diameter of the bolt head (420) in contact with the piston head (220) is greater than the outer diameter of the bolt body (410) compared to when the outer diameter of the bolt head (420) is equal to or smaller than the outer diameter of the bolt body (410), the contact diameter of the bolt head (420) in contact with the piston head (220) is further expanded, thereby improving the load transfer efficiency to the piston part (200) through the bolt head (420). Additionally, as the contact diameter of the bolt head (420) in contact with the piston head (220) is expanded, the load can be stably transferred to the piston part (200), and the centering of the bolt screw part (400) can be stably maintained.

[0085] The bolt head (420) may include a head connection part (421) and a head extension part (422).

[0086] The head connection portion (421) is a part extending from the bolt head (420) toward the bolt body (410) 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 may have an outer diameter larger than the outer diameter of the head connection portion (421). Thus, the contact diameter of the bolt screw portion (400) in contact with the piston portion (200) can be expanded.

[0087] When the outer diameter of the head extension part (422) in contact with the piston head (220) is larger than the outer diameter of the head connection part (421) compared to when the outer diameter of the head extension part (422) in contact with the piston head (220) is equal to the outer diameter of the head connection part (421), the contact diameter of the head extension part (422) in contact with the piston head (220) is further expanded, thereby further improving the load transfer efficiency to the piston part (200) through the bolt head (420). In addition, as the contact diameter of the head extension part (422) in contact with the piston head (220) is expanded, the load transfer to the piston part (200) becomes more stable.

[0088] The head extension (422) may have a curved surface (422a) on the outer circumference facing the piston head (220).

[0089] The head extension portion (422) may have a curved portion (422a) on the outer circumference facing the piston head (220). The curved portion (422a) is formed as a curved surface with a convex shape facing the piston head (220) and may be formed over the entire outer circumference of the head extension portion (422). The head extension portion (422) may come into contact with the piston head (220) on the curved portion (422a).

[0090] The head extension portion (422) can make rolling contact with the piston head (220) on the curved portion (422a). That is, the head extension portion (422) can perform rolling motion with respect to the piston head (220) on the curved portion (422a).

[0091] The piston head (220) may have a flat portion (220a) in contact with the curved portion (422a). Therefore, when the head extension portion (422) comes into contact with the piston head (220) due to the movement of the bolt screw portion (400) in the first direction, even if the head extension portion (422) rolls against the piston head (220), the head extension portion (422) having the convex curved portion (422a) and the piston head (220) having the flat portion (220a) can maintain a state of contact.

[0092] When braking force is generated by the movement of the piston (200) causing the brake disc (20) to frictionally rub against the brake pad (30), the caliper body (100) may have its shape partially deformed due to the reaction of the braking force. As a result, the cylinder (130) and the piston (200) may tilt slightly relative to the center axis compared to the non-braking state. That is, in the braking state, the cylinder (130) and / or the piston (200) may tilt at a fine angle relative to the center axis.

[0093] When the cylinder (130) and / or piston (200) are tilted about their respective central axes, the head extension (422) may come into rolling contact with the piston head (220) on the curved surface (422a). That is, when the cylinder (130) and / or piston (200) are tilted about their central axes, the head extension (422) may roll against the piston head (220) on the curved surface (422a).

[0094] When the cylinder (130) and / or piston (200) is tilted about the central axis, the head extension (422) rolls about the piston head (220), so the bolt head (420) rolls and the bolt body (410) coupled to the bolt head (420) also tilts by the angle of inclination.

[0095] In this way, when the cylinder (130) and / or piston (200) tilts with respect to the central axis, the bolt head (420) and the bolt body (410) also tilt, thereby preventing the load from being concentrated on only a specific ball member (B) among the plurality of ball members (B) arranged along the longitudinal direction of the bolt body (410). By doing so, the robustness of the bolt screw part (400) against the tilting of the cylinder (130) and / or piston (200) can be secured, thereby improving the durability of the vehicle brake device.

[0096] The bearing portion (500) is positioned between the cylinder (130) and the nut screw portion (300) and can support the nut screw portion (300) so that the nut screw portion (300) can rotate inside the cylinder (130).

[0097] The bearing portion (500) may include an outer ring portion (510), a bearing ball (520), and an inner ring portion (530). The outer ring portion (510) is in contact with the inner surface of the cylinder (130). The outer ring portion (510) can be press-fitted into the cylinder (130) to be firmly fixed in position. Since the outer ring portion (510) is press-fitted into the cylinder (130), the load applied to the bearing ball (520) can be distributed through the outer ring portion (510) in the axial direction and / or the outer diameter direction.

[0098] The outer ring portion (510) may include a bearing ball contact portion (515), an outer ring step portion (516), and an outer ring bottom portion (517).

[0099] The outer ring portion (510) may have an outer ring bottom portion (517) formed on the piston head (220) side relative to the bearing ball contact portion (515), and an outer ring stepped portion (516) formed on the nut screw tail (320) side. The outer ring stepped portion (516) is a part that protrudes further inward toward the nut screw portion (300) compared to the outer ring bottom portion (517), and the bearing ball contact portion (515) may be formed between the outer ring stepped portion (516) and the outer ring bottom portion (517).

[0100] The bearing ball contact portion (515) is formed as a curved surface with a concave shape facing inward and can be formed over the entire inner circumference of the outer ring portion (510). The bearing ball (520) can be in direct contact with the bearing ball contact portion (515) or indirectly contacted through another member. In this embodiment, the bearing ball (510) can be seated on the bearing ball contact portion (515).

[0101] The inner ring portion (530) is rotatably positioned on the inner side of the outer ring portion (510) and can be coupled to the nut screw portion (300). The inner ring portion (530) can be press-fitted to the nut screw body (310). A bearing ball (520) is positioned between the outer ring portion (510) and the inner ring portion (530) to reduce friction when the inner ring portion (530) rotates.

[0102] A vehicle brake device according to one embodiment of the present invention may include a position fixing part (550). The position fixing part (550) may contact and support the bearing part (500) on the rear side of the piston head (220) so that the bearing part (500) is fixed in position on the nut screw part (300).

[0103] The position fixing part (550) may include a contact ring part (551). The contact ring part (551) is formed in a ring shape and can contact and support the bearing part (500) from the rear.

[0104] The position fixing part (550) can be firmly connected to the nut screw part (300) by means such as press-fitting. When the position fixing part (550) is connected to the nut screw part (300), the contact ring part (551) can be positioned to contact the inner ring part (530). Thus, the contact ring part (551) can support the inner ring part (530) so that the inner ring part (530) is fixed in position on the nut screw body (310).

[0105] The contact ring portion (551) may be formed to extend from the portion facing the inner ring portion (530) to the portion facing the outer ring portion (510). Accordingly, the contact ring portion (551) may come into contact with at least a portion of the outer ring portion (510) as well as the inner ring portion (530).

[0106] The contact ring portion (551) may be positioned so as to be spaced apart from the outer ring portion (510) by a predetermined distance in the opposite direction of the piston (200). Accordingly, when generating braking force of the vehicle brake device, the contact ring portion (551) and the outer ring portion (510) may be spaced apart by about 0.1 to 0.3 mm, and when releasing the braking force, the outer ring portion (510) may come into contact with the contact ring portion (551), thereby blocking further movement of the outer ring portion (510). Accordingly, during the operation of the vehicle brake device, the displacement of the outer ring portion (510) can be limited to within a set range, thereby improving braking performance.

[0107] The position fixing portion (550) may include an extension ring portion (552) connected to the contact ring portion (551). The extension ring portion (552) may extend from the inner end of the contact ring portion (551) toward the rear, that is, in the opposite direction of the piston (200).

[0108] The inner surface of the extension ring portion (552) can be in close contact with the nut screw body (310). When the position fixing portion (550) is press-fitted into the nut screw body (310), the inner surface of the contact ring portion (551) and the inner surface of the extension ring portion (552) are each press-fitted into the outer surface of the nut screw body (310). Therefore, the position fixing portion (550) can increase the bonding area with the nut screw body (310) through the extension ring portion (552), thereby improving the bonding strength.

[0109] The overall cross-section of the contact ring portion (551) and the extension ring portion (552) can be formed in an approximately L-shape.

[0110] The position fixing part (500) may be made of a metal material. In this embodiment, the position fixing part (500) is made of a steel material, but is not limited thereto and may be replaced with other metal materials.

[0111] When the cylinder (130) and / or piston (200) is tilted about their respective center axis, the inner ring (530) or outer ring (510) may come into rolling contact with the bearing ball (520). That is, when the cylinder (130) and / or piston (200) is tilted about its center axis, the inner ring (530) or outer ring (510) may roll against the bearing ball (520).

[0112] In this way, as the inner ring portion (530) rolls when the cylinder (130) and / or piston (200) tilts with respect to the central axis, the nut screw portion (300) also tilts, thereby preventing the load of the nut screw portion (300) from being concentrated on only a specific ball member (B) among the plurality of ball members (B) arranged in the longitudinal direction of the bolt body (410). By doing so, the robustness of the bolt screw portion (400) against the tilting of the cylinder (130) and / or piston (200) can be secured, thereby improving the durability of the vehicle brake device.

[0113] The inner ring portion (530) may include a rolling contact portion (535), an upper step portion (536), and a lower bottom portion (537).

[0114] The inner ring portion (530) is provided with a rolling contact portion (535) at the portion facing or in contact with the bearing ball (520), so it can perform rolling motion with respect to the bearing ball (520). The outer ring portion (510) is provided with a rolling contact portion (not shown) at the portion facing or in contact with the bearing ball (520), so it can perform rolling motion with respect to the bearing ball (520).

[0115] The inner ring portion (530) may have an upper step portion (536) formed on the piston head (220) side relative to the rolling contact portion (535), and a lower bottom portion (537) formed on the nut screw tail (320) side. The upper step portion (536) is a portion that protrudes outward compared to the lower bottom portion (537), and the rolling contact portion (535) may be formed between the upper step portion (536) and the lower bottom portion (537).

[0116] The rolling contact portion (535) is formed as a curved surface with a concave shape facing inward and can be formed over the entire outer circumference of the inner ring portion (530). The bearing ball (520) can be in direct contact with the rolling contact portion (535) or indirectly contacted through another member.

[0117] Since the rolling contact portion (535) has a curved portion, the nut screw body (310) can roll relative to the cylinder (130).

[0118] When braking a vehicle brake device, the piston part (200) may be tilted about the center axis or the cylinder (130) may be tilted about the center axis due to braking torque or the opening of the caliper body (100). According to the present embodiment, since the bolt head (420) can roll against the piston part (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) disposed on the outer surface of the bolt screw part (400). In addition, according to the present embodiment, since the inner ring part (530) rolls against the bearing ball (520) and the nut screw part (300) can roll against the cylinder (130), it is possible to prevent the load from being concentrated only on a specific ball member (B) among the plurality of ball members (B) disposed on the inner surface of the nut screw part (300).

[0119] The vehicle brake device according to the present embodiment is capable of rolling motion at the front portion of the bolt screw portion (400), at the outer portion of the nut screw (300), or at the front portion of the bolt screw portion (400) and the outer portion of the nut screw (300). Therefore, even when the piston portion (200) is tilted about the central axis or the cylinder (130) is tilted about the central axis, the specific ball member (B) can be suppressed from receiving a concentrated load. Thus, the vehicle brake device according to the present embodiment can improve the durability of the device while ensuring robustness against tilting.

[0120] A vehicle brake device according to one embodiment of the present invention may further include an actuator part (600).

[0121] The actuator part (600) can receive power from the motor part (660) and provide rotational force to the nut screw part (300).

[0122] The actuator section (600) may be equipped with a power transmission section. The power transmission section may engage with the nut screw section (300) to transmit rotational force to the nut screw section (300). As the nut screw section (300) rotates due to the rotational force provided by the actuator section (600), the bolt screw section (400) may be translated.

[0123] This embodiment is a nut screw driven type vehicle brake device in which a nut screw portion (300) rotates first by receiving rotational force from an actuator (600), and a bolt screw portion (400), which is power-coupled to the nut screw portion (300) by a ball member (B), rotates in succession. Accordingly, according to this embodiment, the axial length can be reduced compared to a bolt screw driven type vehicle brake device.

[0124] The power transmission unit may include a plurality of gears that are sequentially engaged and coupled between the motor unit (660) and the nut screw unit (300). The power transmission unit is not limited to this configuration, and the design can be modified to various types of power transmission means capable of receiving rotational force from the motor unit (660) and rotating the nut screw unit (300).

[0125] The power transmission unit may include a power transmission groove (620) disposed inside the actuator housing (610).

[0126] The power transmission groove (620) is positioned to surround the anti-rotation projection (630), and the nut screw tail (320) of the nut screw portion (300) can be inserted.

[0127] The power transmission groove (620) may be formed in a shape corresponding to the nut screw tail (320) so as to engage with the nut screw tail (320). The power transmission groove (620) may be formed as a non-circular groove. Non-circular means a shape that is not a perfect circle, and includes shapes such as elliptical and polygonal. In this embodiment, the power transmission groove (620) is formed as a polygonal groove, specifically a roughly hexagonal groove.

[0128] Since the nut screw tail (320) and the power transmission groove (620) are each formed as non-circular shapes, but are formed with the same shape or a corresponding shape, when the nut screw tail (320) is inserted into the power transmission groove (620), the nut screw tail (320) and the power transmission groove (620) interlock with each other. Therefore, when the power transmission groove (620) rotates during the operation of the actuator (600), the nut screw tail (320) interlocked with the power transmission groove (620) also rotates in the same direction. As a result, the rotational force of the actuator (600) can be stably transmitted to the nut screw part (300) without loss.

[0129] The actuator part (600) may be equipped with a rotation prevention part. The rotation prevention part may engage with the bolt screw part (400) to restrict the rotation of the bolt screw part (400). As the nut screw part (300) rotates due to the rotational force provided by the actuator part (600), the bolt screw part (400) is translated.

[0130] Since the nut screw part (300) and the bolt screw part (400) are power-coupled via a ball member (B), the rotation of the bolt screw part (400) is blocked by a rotation prevention part so that the rotation of the nut screw part (300) is converted into translational movement of the bolt screw part (400).

[0131] The anti-rotation portion may include an anti-rotation projection (630). The anti-rotation projection (630) may be positioned inside the actuator housing (610) and may protrude to the outside of the actuator housing (610). The anti-rotation projection (630) may be positioned inside the power transmission groove portion (620).

[0132] When the nut screw tail (320) is inserted into the power transmission groove (620) and interlocks with each other, the anti-rotation projection (630) can be inserted into the anti-rotation groove (411) of the bolt body (410) and interlock with each other. As such, according to the present embodiment, power transmission to the nut screw part (300) and anti-rotation to the bolt screw part (400) can be achieved by a single assembly, thereby greatly improving assembly efficiency.

[0133] The anti-rotation projection (630) may be formed in a non-circular column shape. Non-circular means a shape that is not a perfect circle, and includes shapes such as elliptical and polygonal. In this embodiment, the anti-rotation projection (630) is formed in a polygonal column shape, specifically a roughly hexagonal column shape.

[0134] The anti-rotation groove (411) may be formed in the bolt body (410) in a shape corresponding to the anti-rotation projection (630) so as to engage with the anti-rotation projection (630). The anti-rotation groove (411) may be formed as a non-circular groove. Non-circular means a shape that is not a perfect circle, and includes shapes such as elliptical and polygonal. In this embodiment, the anti-rotation groove (411) is formed as a polygonal groove, specifically a roughly hexagonal groove.

[0135] The anti-rotation projection (630) and the anti-rotation groove (411) are each formed as non-circular shapes, but are formed with the same shape or a corresponding shape. Therefore, when the anti-rotation projection (630) is inserted into the anti-rotation groove (411), the anti-rotation projection (630) and the anti-rotation groove (411) interlock with each other. Accordingly, when the power transmission groove (620) rotates during the operation of the actuator (600), the nut screw tail (320) engaged with the power transmission groove (620) rotates in the same direction, but the rotation of the bolt body (410) is blocked. As a result, the rotational force of the actuator (600) can be stably converted into the translational movement of the bolt screw part (400) without loss.

[0136] Since the anti-rotation projection (630) and the anti-rotation groove (411) are in surface contact, the loss of frictional force can be reduced when an axial forward load occurs, and the centering of the bolt body (410) can be maintained. In addition, since the anti-rotation groove (411) can be formed integrally with the bolt body (410), there is no need to manufacture an anti-rotation structure separately, thus increasing space utilization.

[0137] The anti-rotation groove (411) may be provided with an outwardly extending inclined surface (411a) to induce the insertion of the anti-rotation projection (630). The anti-rotation projection (630) may be provided with a tapered inclined surface (630a) on the outer side of the tip portion to allow for easier insertion into the anti-rotation groove (411).

[0138] The length at which the anti-rotation projection (630) is inserted into the bolt body (410) may be greater than the maximum stroke of the piston part (200). The maximum stroke of the piston part (200) refers to the distance the piston part (200) moves from its original position to its maximum forward position, and the stroke of the piston part (200) may increase by the amount of wear when the brake pad (30) is worn. Therefore, since the length at which the anti-rotation projection (630) is inserted into the bolt body (410) is greater than the maximum stroke of the piston part (200), the anti-rotation projection (630) is always kept engaged with the anti-rotation groove (411) of the bolt body (410), so the rotation of the bolt screw part (400) can always be blocked.

[0140] Although the present invention has been described with reference to the embodiments illustrated in the drawings, this is merely illustrative, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible therefrom. Accordingly, the true technical scope of protection of the present invention should be determined by the claims below. Explanation of the symbols

[0142] 20: Brake disc 30: Brake pad 100: Caliper body 130: Cylinder 200: Piston 210: Piston body 220: Piston head 300: Nut screw part 310: Nut screw body 320: Nut screw tail 400: Bolt screw section 410: Bolt body 420: Bolt head 500: Bearing part 600: Actuator 620: Power transmission groove 630: Anti-rotation protrusion

Claims

Claim 1 A caliper body equipped with a cylinder; a piston portion movably disposed in the cylinder and positioned opposite a brake pad; a nut screw portion disposed inside the piston portion, rotates by receiving rotational force from an actuator, and is provided with an outer ball rail on its inner surface that forms a circulation path for a ball member; a bolt screw portion comprising a bolt body coupled to the nut screw portion and receiving rotational force from the nut screw portion, and a bolt head provided separately from the bolt body, coupled to the bolt body and positioned opposite the piston portion, wherein an inner ball rail is provided on the outer surface of the bolt body to face the outer ball rail and forms a circulation path for the ball member; a bearing portion disposed between the cylinder and the nut screw portion and supporting the nut screw portion so that the nut screw portion can rotate inside the cylinder; A brake device for a vehicle, characterized in that it includes a position fixing part that contacts and supports the bearing part so that the bearing part is fixed in position on the nut screw part, and the nut screw part includes a first return hole part through which the ball member can be inserted and removed, a return passage communicating with the first return hole part, and a second return hole part communicating with the return passage and through which the ball member can be inserted and removed. Claim 2 A vehicle brake device according to claim 1, characterized in that the ball member that enters the first return hole section is guided to the second return hole section through the return passage, and the ball member that enters the second return hole section is guided to the first return hole section through the return passage. Claim 3 A vehicle brake device according to claim 2, characterized in that the first return hole portion is positioned closer to the piston portion than the second return hole portion. Claim 4 A vehicle brake device according to claim 1, wherein the bearing portion comprises: an outer ring portion in contact with the inner surface of the cylinder; an inner ring portion rotatable within the outer ring portion and in contact with the nut screw portion; and a bearing ball disposed between the outer ring portion and the inner ring portion. Claim 5 In paragraph 4, A vehicle brake device characterized in that the above position fixing part includes a contact ring part that contacts the inner ring part when coupled to the above nut screw part. Claim 6 In paragraph 5, A vehicle brake device characterized in that the contact ring portion is positioned opposite to the piston and spaced apart from the outer ring portion by a predetermined distance. Claim 7 In paragraph 5, A vehicle brake device characterized in that the above position fixing part is connected to the above contact ring part and further includes an extension ring part that extends in the opposite direction of the piston and makes surface contact with the above nut screw part. Claim 8 A vehicle brake device according to claim 1, characterized in that the position fixing part comprises a metal material. Claim 9 A vehicle brake device according to claim 1, wherein the bolt head comprises: a head connecting portion coupled to the bolt body and having an outer diameter larger than the outer diameter of the bolt body; and a head extension portion extending from the head connecting portion toward the piston portion and having an outer diameter larger than the outer diameter of the head connecting portion. Claim 10 A vehicle brake device according to claim 9, wherein the head extension portion has a curved surface portion on the outer circumference facing the piston portion, and the head extension portion contacts the piston portion on the curved surface portion.

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