Brake apparatus for vehicle

Abstract

The present invention relates to a brake device for a vehicle, comprising: a caliper body having a cylinder; a nut screw rotatably disposed in the cylinder; a bolt screw movable in conjunction with the rotation of the nut screw in a first direction or in a second direction opposite to the first direction; a piston movably disposed in the cylinder, moved in the first direction by the pressure of the bolt screw, and interfering with the bolt screw to restrict the rotation of the bolt screw; and a retainer fixed to the cylinder and interfering with the piston to restrict the rotation of the piston.

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

[0002] 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.

[0003] 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.

[0004] These EMBs enable 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 can achieve higher performance due to the absence of hydraulic transmission delay.

[0005] 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

[0006] The objective of the present invention is to provide a vehicle brake device capable of securing stable braking performance. means of solving the problem

[0007] A vehicle brake device according to the present invention, devised to achieve the above objective, comprises: a caliper body having a cylinder; a nut screw rotatably disposed in the cylinder; a bolt screw movable in conjunction with the rotation of the nut screw in a first direction or in a second direction opposite to the first direction; a piston movably disposed in the cylinder, moved in the first direction by the pressure of the bolt screw, and interferes with the bolt screw to restrict the rotation of the bolt screw; and a retainer fixed to the cylinder and interferes with the piston to restrict the rotation of the piston.

[0008] The above piston may include a piston body portion into which the bolt screw is inserted, a first interference portion provided on the inner circumference of the piston body portion and interfering with the bolt screw, and a second interference portion provided on the outer circumference of the piston body portion and interfering with the retainer.

[0009] The first interference part may be formed protruding from the inner circumferential surface of the piston body part, and the second interference part may be formed recessed from the outer circumferential surface of the piston body part.

[0010] The second interference portion may be extended along a direction parallel to the first direction and the second direction.

[0011] The above bolt screw may include a bolt body portion coupled to the nut screw and a ball member, a bolt head portion that pressurizes the piston body portion, and a third interference portion provided on the outer surface of the bolt head portion and capable of contacting the first interference portion.

[0012] The above third interference part may form a flat surface by cutting off a portion of the outer surface of the above bolt head part.

[0013] The above retainer may include a ring-shaped retainer body portion disposed between the cylinder and the piston, and a fourth interference portion provided on the inner circumference of the retainer body portion and capable of contacting the second interference portion.

[0014] The above-mentioned fourth interference part may be formed protruding from the inner circumference of the above-mentioned retainer body part.

[0015] The above retainer may further include a damper portion that is coupled to the retainer body portion and can contact the piston.

[0016] The above damper part may further be provided with a projection that rests on the piston. Effects of the invention

[0017] The present invention has the effect of preventing rotation of the piston by interfering with the fourth interference part formed on the retainer, and preventing rotation of the bolt screw by interfering with the first interference part formed on the piston by the third interference part formed on the bolt head.

[0018] The present invention has the effect of maintaining the centering of the piston by applying the elastic force of a projection formed in the damper portion toward the center of the piston to the piston.

[0019] The present invention has the effect of minimizing sliding resistance of the piston by forming a stable lubricating film when the piston moves, as the groove formed between a plurality of protrusions acts as a grease (lubricant) pocket. Brief explanation of the drawing

[0020] FIG. 1 is a perspective view of a vehicle brake device according to an embodiment of the present invention, viewed from one direction. FIG. 2 is a perspective view of FIG. 1 seen from a different direction. FIG. 3 is a cross-sectional view schematically showing a vehicle brake device according to a first embodiment of the present invention, Fig. 4 is a partial enlarged view of Fig. 3, FIG. 5 is an exploded perspective view of the configuration of a vehicle brake device according to a first embodiment of the present invention, viewed from one direction. FIG. 6 is an exploded perspective view of FIG. 5 viewed from a different direction. FIG. 7 is a cross-sectional view schematically showing a vehicle brake device according to a second embodiment of the present invention. Fig. 8 is a partial enlarged view of Fig. 7, FIG. 9 is an exploded perspective view of the configuration of a vehicle brake device according to a second embodiment of the present invention, viewed from one direction. FIG. 10 is an exploded perspective view of FIG. 9 viewed from a different direction. FIGS. 11 and 12 are partially enlarged cross-sectional views schematically illustrating the assembly process of a vehicle brake device according to an embodiment of the present invention. Specific details for implementing the invention

[0021] 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.

[0023] FIG. 1 is a perspective view of a vehicle brake device according to an embodiment of the present invention viewed from one direction, FIG. 2 is a perspective view of FIG. 1 viewed from another direction, FIG. 3 is a cross-sectional view schematically showing a vehicle brake device according to a first embodiment of the present invention, FIG. 4 is a partial enlarged view of FIG. 3, FIG. 5 is an exploded perspective view of the configuration of a vehicle brake device according to a first embodiment of the present invention viewed from one direction, and FIG. 6 is an exploded perspective view of FIG. 5 viewed from another direction.

[0024] Referring to FIGS. 1 to 6, a vehicle brake device according to the first embodiment of the present invention includes a caliper body (100), a piston (200), a nut screw (300), a bolt screw (400), and a retainer (500), which are described in detail as follows.

[0025] The caliper body (100) forms the general appearance of a vehicle brake device according to the present embodiment and can support the piston (200), nut screw (300), bolt screw (400), and retainer (500) in its entirety.

[0026] The caliper body (100) according to the present embodiment may include a bridge (110), a finger (120), and a cylinder (130).

[0027] The bridge (110) forms the central exterior of the caliper body (100) and can support the finger (120) and cylinder (130). The bridge (110) can be connected to a carrier (10) fixed to a knuckle (not shown), etc. via a guide rod (11).

[0028] The bridge (110) can be connected to the carrier (10) so as to be reciprocally movable along a first direction (D1) or a second direction (D2). The first direction (D1) and the second direction (D2) can be exemplified as opposite directions to each other and parallel to the X-axis with respect to the center axis (C1) of the brake disc (20), i.e., FIG. 3.

[0029] The lower surface of the bridge (110) may be positioned to face the circumferential surface of the brake disc (20) at a set distance. Both sides of the bridge (110) may extend along the first direction (D1) and the second direction (D2), respectively, with respect to the brake disc (20).

[0030] A pair of brake pads (30) may be positioned on the lower side of the bridge (110). The pair of brake pads (30) may be spaced apart from each other along the central axis (C1) of the brake disc (20). The pair of brake pads (30) may be positioned facing each other with the brake disc (20) in between.

[0031] One of the pair of brake pads (30) may be spaced apart from the brake disc (20) along a first direction (D1), and the other brake pad (30) may be spaced apart from the brake disc (20) along a second direction (D2).

[0032] A pair of brake pads (30) may be supported on a carrier (10) or a bridge (110) so as to be slidable in a first direction (D1) and a second direction (D2). 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).

[0033] The finger (120) may extend downward from one side of the bridge (110). The finger (120) may be positioned to face one of the pair of brake pads (30).

[0034] The finger (120) can be positioned to face the brake pad (30) that is spaced apart from the brake disc (20) in a first direction (D1) among a pair of brake pads (30).

[0035] The finger (120) can press the brake pad (30), which is spaced apart from the brake disc (20) in the first direction (D1), toward the brake disc (20) when the bridge (110) moves along the second direction (D2).

[0036] 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 cylinder that is hollow inside and has one side open. The open side of the cylinder (130) may be positioned to face the other brake pad (30) of the pair of brake pads (30).

[0037] The open side of the cylinder (130) may be positioned to face the brake pad (30) that is spaced apart from the brake disc (20) in a second direction (D2) among a pair of brake pads (30). The open side of the cylinder (130) may be spaced apart from the brake pad (30) that is spaced apart from the brake disc (20) in a second direction (D2) at a set distance.

[0038] The central axis (C2) of the cylinder (130) may be positioned parallel to the central axis (C1) of the brake disc (20). The central axis (C2) of the cylinder (130) may be spaced apart from the central axis (C1) of the brake disc (20) along a third direction (D3).

[0039] The third direction (D3) is perpendicular to the first direction (D1) and the second direction (D2) and can be exemplified as a direction from the center axis (C1) of the brake disc (20) toward the center axis (C2) of the cylinder (130).

[0040] The third direction (D3) may be a direction perpendicular to the ground, i.e., a direction rising along the Z-axis direction with respect to FIG. 3, when the lower surface of the bridge (110) is positioned parallel to the ground.

[0041] The piston (200) may be installed in the cylinder (130) so as to be movable in a first direction (D1) or a second direction (D2). The piston (200) may be positioned inside the cylinder (130). The piston (200) may be formed in a hollow shape with one side open. The closed side of the piston (200) may be positioned to face the brake pad (30) which is positioned facing the cylinder (130).

[0042] The open side of the piston (200) may be positioned to face the internal space of the cylinder (130). The outer surface of the piston (200) may be slidably supported on the inner surface of the cylinder (130). Alternatively, the outer surface of the piston (200) may be spaced apart from the inner surface of the cylinder (130) by a set distance to form a gap.

[0043] As the piston (200) moves in the first direction (D1), 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).

[0044] The bridge (110) can be moved in a second direction (D2) by the reaction force generated between the piston (200) and the brake pad (30). As the piston (200) moves in the second direction (D2), it releases the pressure applied to the brake pad (30) and can be separated from the brake pad (30).

[0045] The piston (200) may interfere with the bolt screw (400) to restrict the rotation of the bolt screw (400). The bolt screw (400) may interfere with the piston (200) to restrict its axial rotation. The piston (200) may include a piston body part (210), a first interference part (220), and a second interference part (230).

[0046] The piston body portion (210) forms the overall exterior of the piston (200) and can be formed in the shape of a cylinder with a hollow interior. A bolt screw (400) can be inserted into the inner side of the piston body portion (210). Additionally, a bolt head portion (420) can be inserted into the piston body portion (210).

[0047] The first interference portion (220) may be provided on the inner circumference of the piston body portion (210). The first interference portion (220) may interfere with the bolt screw (400). Additionally, the first interference portion (220) may interfere with the bolt head portion (420).

[0048] The first interference portion (220) may be formed protruding from the inner circumference of the piston body portion (210). The first interference portion (220) may extend from the inner circumference of the piston body portion (210) toward the center of the piston body portion (210) with a set thickness. The first interference portion (220) may be formed as a flat surface.

[0049] In another embodiment, when the third interference part (430) has a convex shape, the first interference part (220) may be formed by being recessed into the inner circumference of the piston body part (210).

[0050] The first interference portion (220) may be provided in multiple numbers. The multiple first interference portions (220) may be spaced apart along the circumferential direction of the piston body portion (210). For example, a pair of first interference portions (220) may be arranged facing each other.

[0051] A pair of first interference parts (220) may be positioned on both sides of the piston body part (210). Additionally, a pair of first interference parts (220) may be positioned at the 3 o'clock and 9 o'clock directions of the piston body part (210) when viewed from the front.

[0052] The second interference portion (230) may be provided on the outer surface of the piston body portion (210). The second interference portion (230) may interfere with the retainer (500). Additionally, the second interference portion (230) may interfere with the fourth interference portion (520).

[0053] The second interference portion (230) may be formed by being recessed on the outer surface of the piston body portion (210). The second interference portion (230) may be formed to have the shape of a groove.

[0054] In another embodiment, if the fourth interference part (520) has a concave shape, the second interference part (230) may be formed protruding from the outer surface of the piston body part (210).

[0055] The second interference part (230) can guide the linear movement of the piston (200) moving in the first direction (D1) or the second direction (D2). The second interference part (230) can extend along the direction of the central axis (C3) of the piston (200).

[0056] The second interference portion (230) may extend along the longitudinal direction of the piston body portion (210), that is, in a direction parallel to the first direction (D1) and / or the second direction (D2). The second interference portion (230) may be formed in the shape of an elongated hole having a set length.

[0057] A piston boot (600) 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 (600) may be installed between the cylinder (130) and the piston (200). The piston boot (600) may be coupled to the piston body part (210) and pressed into the inner side of the cylinder (130).

[0058] The piston boot (600) may be formed to surround the piston body portion (210). The piston boot (600) may be positioned along a first direction from the second interference portion (230) and the retainer (500). The piston boot (600) may come into contact with the retainer (500).

[0059] The piston boot (600) may include an elastically deformable material. For example, the piston boot (600) may be manufactured including a rubber material. The piston boot (600) may be formed to have a corrugated shape.

[0060] A nut screw (300) is rotatably positioned in a cylinder (130) and can be connected to a bolt screw (400). A bearing (700) that rotatably supports the nut screw (300) may be installed inside the cylinder (130). The bearing (700) may be exemplified as a ball bearing provided between the cylinder (130) and the nut screw (300).

[0061] The nut screw (300) may be formed in a hollow shape with an empty interior and open ends. The nut screw (300) may be positioned inside the cylinder (130), and its central axis may be located on the same axis as the central axis (C2) of the cylinder.

[0062] One side of the nut screw (300) (left side in Fig. 3) may be positioned facing the inner surface of the piston (200) at a set distance. The other side of the nut screw (300) (right side in Fig. 3) may penetrate the closed side of the cylinder (130) and protrude to the outside of the cylinder (130).

[0063] The other end of the nut screw (300) may be connected to a power transmission means (not shown) that receives rotational force from an actuator (not shown). The actuator may be exemplified by various types of electric motors capable of generating rotational force by receiving power from a vehicle battery (not shown), etc.

[0064] The power transmission means can transmit the rotational force of the actuator to the nut screw (300). The power transmission means may include a plurality of gears that are sequentially engaged and coupled between the actuator and the nut screw (300). However, the power transmission means is not limited to such a configuration, and the design can be modified to various types of power transmission means capable of receiving rotational force from the actuator and rotating the nut screw (300).

[0065] The nut screw (300) receives rotational force generated from the actuator through a power transmission means when the actuator operates, and can be rotated clockwise or counterclockwise around a central axis.

[0066] The nut screw (300) may be positioned so that its inner surface faces the outer surface of the bolt screw (400). A ball rail may be formed on the inner circumference of the nut screw (300) on which one side of a spherical ball member (B) is seated. This ball rail may extend in a spiral shape along the longitudinal direction of the nut screw (300) to provide a circulation path for the ball member (B).

[0067] The bolt screw (400) can be moved in a first direction (D1) or a second direction (D2) inside the cylinder (130) in conjunction with the rotation of the nut screw (300). The bolt screw (400) can be positioned inside the nut screw (300). The bolt screw (400) can be positioned to penetrate both ends of the nut screw (300).

[0068] The bolt screw (400) can press the piston (200) in the first direction (D1) as it moves in the first direction (D1), and release the pressure on the piston (200) as it moves in the second direction (D2).

[0069] The bolt screw (400) may include a bolt body part (410), a bolt head part (420), and a third interference part (430).

[0070] The bolt body portion (410) may be formed in a rod shape having a roughly circular cross-section. The bolt body portion (410) is positioned inside the cylinder (130), and its central axis may be located on the same axis as the central axis (C2) of the cylinder (130). The bolt body portion (410) may be joined to the nut screw (300) and the ball member (B) via a ball member.

[0071] A ball rail may be formed on the outer surface of the bolt body portion (410) on which the other circumference of the ball member (B) rests. This ball rail may extend in a spiral shape along the longitudinal direction of the bolt body portion (410) to provide a circulation path for the ball member (B). Accordingly, when the nut screw (300) rotates, the bolt body portion (410) may be moved in a first direction (D1) or a second direction (D2) by the circulation movement of the ball member (B).

[0072] The bolt head portion (420) may be positioned between the bolt body portion (410) and the piston (200). The bolt head portion (420) may be formed to have a roughly circular cross-section. The bolt head portion (420) may be inserted into the piston body portion (210). The bolt head portion (420) may be positioned facing the inner surface of the piston body portion (210) at a set distance.

[0073] The bolt head portion (420) can press the piston body portion (210). The bolt head portion (420) can press the piston body portion (210) in a first direction (D1) or release the pressure depending on the direction of movement of the bolt body portion (410).

[0074] The bolt head portion (420) may be provided on one side (left side based on FIG. 3) of the bolt body portion (410) which is positioned facing the piston (200).

[0075] The diameter of the bolt head portion (420) can be formed to be larger than the diameter of the bolt body portion (410). The outer diameter of the bolt head portion (420) can be formed to be larger than the inner diameter of the nut screw (300). Accordingly, the bolt head portion (420) can protrude from the nut screw (300).

[0076] The bolt head portion (420) contacts the inner surface of the piston body portion (210) as the bolt body portion (410) moves in the first direction (D1), and can press the piston body portion (210) in the first direction (D1).

[0077] The bolt head portion (420) can be separated from the inner surface of the piston body portion (210) as the bolt body portion (410) moves in the second direction (D2), and the pressure applied to the piston body portion (210) can be released.

[0078] The third interference part (430) may be provided on the outer surface of the bolt head part (420). The third interference part (430) may come into contact with the first interference part (220). The third interference part (430) may interfere with the first interference part (220).

[0079] The third interference portion (430) may be formed as a flat plane corresponding to the first interference portion (220). The third interference portion (430) may be formed as a flat plane by cutting off a portion of the outer surface of the bolt head portion (420).

[0080] The third interference portion (430) may come into surface contact with the first interference portion (220). In another embodiment, if the first interference portion (220) has a concave shape, the third interference portion (430) may be formed protruding from the outer surface of the bolt head portion (420).

[0081] The third interference portion (430) may be provided in multiple numbers. The multiple third interference portions (430) may be spaced apart along the circumferential direction of the bolt head portion (420). For example, a pair of third interference portions (430) may be arranged facing each other.

[0082] A pair of third interference parts (430) may be positioned on both sides of the bolt head part (420). To elaborate, the pair of third interference parts (430) may be positioned at the 3 o'clock and 9 o'clock directions of the bolt head part (420) when viewed from the front. That is, the third interference parts (430) may be positioned at a location corresponding to the first interference part (220). As the third interference part (430) interferes with the first interference part (220), the axial rotation of the bolt screw (400) may be restricted.

[0083] The bolt head portion (420) according to the present embodiment may further be provided with a pressurizing portion (421) that contacts the inner surface of the piston body portion (210).

[0084] The pressure portion (421) may be formed protruding from the bolt head portion (420). The pressure portion (421) may protrude from the outer surface of the bolt head portion (420) and may be formed along the circumferential direction of the bolt head portion (420).

[0085] The pressurizing part (421) may be provided on one side (left side according to FIG. 4) of the bolt head part (420) facing the direction in which the piston (200) is located.

[0086] The retainer (500) can be fixed to the cylinder (130). The retainer (500) can interfere with the piston (200) to restrict the rotation of the piston (200). The piston (200) can interfere with the retainer (500) to restrict its axial rotation. The retainer (500) may include a metal material.

[0087] The retainer (500) may include a retainer body part (510) and a fourth interference part (520).

[0088] The retainer body portion (510) may be formed in a ring shape. The retainer body portion (510) may be positioned between the cylinder (130) and the piston (200). The retainer body portion (510) may be interposed between the inner surface of the cylinder (130) and the outer surface of the piston body portion (210).

[0089] The outer surface of the retainer body part (510) is in close contact with the inner surface of the cylinder (130), and the inner surface of the retainer body part (510) can be in close contact with the outer surface of the piston body part (210).

[0090] The retainer body part (510) can be fixed to the cylinder (130) by a joining method such as bolting or pin joining to the inner surface of the cylinder (130), and can be fixed to the cylinder (130) by an assembly method such as press-fitting or serration press-fitting to the inner side of the cylinder (130).

[0091] The fourth interference part (520) may be provided on the inner circumference of the retainer body part (510). The fourth interference part (520) may come into contact with the second interference part (230). The fourth interference part (520) may interfere with the second interference part (230).

[0092] The fourth interference portion (520) may be formed protruding from the inner circumference of the retainer body portion (510). The fourth interference portion (520) may be formed to have the shape of a protrusion. The fourth interference portion (520) may extend from the inner circumference of the retainer body portion (510) toward the center of the retainer body portion (510) with a set thickness.

[0093] The fourth interference part (520) can be accommodated in the second interference part (230) and seated on the inside of the second interference part (230).

[0094] In another embodiment, if the second interference portion (230) has a convex shape, the fourth interference portion (520) may be formed by being embedded in the inner circumference of the retainer body portion (510).

[0095] The fourth interference portion (520) may be provided in multiple numbers. The multiple fourth interference portions (520) may be spaced apart along the circumferential direction of the retainer body portion (510). For example, a pair of fourth interference portions (520) may be arranged facing each other.

[0096] A pair of fourth interference parts (520) may be positioned on both sides of the retainer body part (510). To elaborate, a pair of fourth interference parts (520) may be positioned at the 3 o'clock and 9 o'clock directions of the retainer body part (510) when viewed from the front. That is, the fourth interference parts (520) may be positioned at a location corresponding to the second interference part (230).

[0097] The axial rotation of the piston (200) can be restricted because the retainer body part (510) is fixed to the cylinder (130) and the fourth interference part (520) interferes with the second interference part (230). As the axial rotation of the piston (200) is restricted, the axial rotation of the bolt screw (400) can be restricted.

[0098] Additionally, as the fourth interference part (520) is seated on the inner side of the second interference part (230), the linear movement of the piston (200) moving in the first direction (D1) or the second direction (D2) can be guided.

[0099] FIG. 7 is a schematic cross-sectional view of a vehicle brake device according to a second embodiment of the present invention, FIG. 8 is a partial enlarged view of FIG. 7, FIG. 9 is an exploded perspective view of the configuration of a vehicle brake device according to a second embodiment of the present invention viewed from one direction, and FIG. 10 is an exploded perspective view of FIG. 9 viewed from another direction.

[0100] Referring to FIGS. 1 to 10, a vehicle brake device according to a second embodiment of the present invention may include a caliper body (100), a piston (200), a nut screw (300), a bolt screw (400), and a retainer (500).

[0101] In describing a vehicle brake device according to a second embodiment of the present invention, we will describe another embodiment of the retainer (500) in the vehicle brake device according to the first embodiment of the present invention and a damper part (530) that is not described in the vehicle brake device according to the first embodiment of the present invention.

[0102] For the remaining components of the vehicle brake device according to the second embodiment of the present invention, the description of the vehicle brake device according to the first embodiment of the present invention may be applied as is.

[0103] The retainer (500) can be fixed to the cylinder (130). The retainer (500) can interfere with the piston (200) to restrict the rotation of the piston (200). The piston (200) can interfere with the retainer (500) to restrict its axial rotation. The retainer (500) may include a metal material.

[0104] The retainer (500) may include a retainer body part (510), a fourth interference part (520), and a damper part (530).

[0105] The retainer body portion (510) may be formed in a ring shape. The retainer body portion (510) may be positioned between the cylinder (130) and the piston (200). The retainer body portion (510) may be interposed between the inner surface of the cylinder (130) and the outer surface of the piston body portion (210).

[0106] The retainer body part (510) can be fixed to the cylinder (130) by a joining method such as bolting or pin joining to the inner surface of the cylinder (130), and can be fixed to the cylinder (130) by an assembly method such as press-fitting or serration press-fitting to the inner side of the cylinder (130).

[0107] The fourth interference part (520) may be provided on the inner circumference of the retainer body part (510). The fourth interference part (520) may come into contact with the second interference part (230). The fourth interference part (520) may interfere with the second interference part (230).

[0108] The fourth interference portion (520) may be formed protruding from the inner circumference of the retainer body portion (510). The fourth interference portion (520) may be formed to have the shape of a protrusion. The fourth interference portion (520) may extend from the inner circumference of the retainer body portion (510) toward the center of the retainer body portion (510) with a set thickness.

[0109] The fourth interference part (520) can be accommodated in the second interference part (230) and seated on the inside of the second interference part (230).

[0110] In another embodiment, if the second interference portion (230) has a convex shape, the fourth interference portion (520) may be formed by being embedded in the inner circumference of the retainer body portion (510).

[0111] The fourth interference portion (520) may be provided in multiple numbers. The multiple fourth interference portions (520) may be spaced apart along the circumferential direction of the retainer body portion (510). For example, a pair of fourth interference portions (520) may be arranged facing each other.

[0112] A pair of fourth interference parts (520) may be positioned on both sides of the retainer body part (510). To elaborate, a pair of fourth interference parts (520) may be positioned at the 3 o'clock and 9 o'clock directions of the retainer body part (510) when viewed from the front. That is, the fourth interference parts (520) may be positioned at a location corresponding to the second interference part (230).

[0113] The axial rotation of the piston (200) can be restricted because the retainer body part (510) is fixed to the cylinder (130) and the fourth interference part (520) interferes with the second interference part (230). As the axial rotation of the piston (200) is restricted, the axial rotation of the bolt screw (400) can be restricted.

[0114] Additionally, as the fourth interference part (520) is seated on the inner side of the second interference part (230), the linear movement of the piston (200) moving in the first direction (D1) or the second direction (D2) can be guided.

[0115] The damper portion (530) can be coupled to the retainer body portion (510). The damper portion (530) can be provided in a form that surrounds the retainer body portion (510). The damper portion (530) can come into contact with the piston (200).

[0116] The damper portion (530) may be positioned between the retainer body portion (510) and the piston (200). The damper portion (530) may be positioned between the inner surface of the retainer body portion (510) and the outer surface of the piston body portion (210). The damper portion (530) may be in close contact with the piston body portion (210).

[0117] The damper portion (530) may include an elastically deformable material. For example, the damper portion (530) may be manufactured including a rubber material. The damper portion (530) may be integrally provided with the retainer body portion (510). The damper portion (530) may be insert-molded into the retainer (500). The fourth interference portion (520) may protrude from the damper portion (530).

[0118] The damper part (530) can elastically support the piston (200). Additionally, the damper part (530) can elastically support the piston body part (210).

[0119] The damper portion (530) may further be provided with a projection portion (531). The projection portion (531) may be formed protrudingly on the outer surface of the damper portion (530) that contacts the piston body portion (210). The projection portion (531) may be seated on the piston (200). The projection portion (531) may be seated on the outer circumference of the piston body portion (210).

[0120] Multiple protrusions (531) may be spaced apart along the direction of the central axis (C4) of the retainer (500). Here, the central axis (C4) of the retainer (500) and the central axis (C3) of the piston (200) may be located on the same axis.

[0121] The elastic force of the protrusion (531) is applied to the piston (200) toward the center of the piston (200), so that the piston (200) can maintain centering. As a result, when the piston (200) moves in the first direction (D1) or the second direction (D2), smooth linear movement is possible, thereby ensuring the straightness of the piston (200).

[0122] Additionally, the protrusion (531) can reduce rattle noise by absorbing vibrations that occur as the piston (200) moves in the first direction (D1) or the second direction (D2).

[0123] A groove formed between a plurality of protrusions (531) spaced apart along the central axis (C4) of the retainer (500) acts as a grease (lubricant) pocket, thereby forming a stable lubricating film when the piston (200) moves in the first direction (D1) or the second direction (D2), so that the sliding resistance of the piston (200) can be kept to a minimum.

[0124] The assembly process of a vehicle brake device according to an embodiment of the present invention, which is configured as described above, is as follows.

[0125] FIGS. 11 and 12 are partially enlarged cross-sectional views schematically illustrating the assembly process of a vehicle brake device according to an embodiment of the present invention.

[0126] Referring to FIG. 11, a retainer (500) is pressed into the cylinder (130). A load is applied to the retainer body portion (510) in a second direction to press the retainer body portion (510) into the inside of the cylinder (130). The retainer body portion (510) can be fixed to the cylinder (130) by an assembly method such as pressing into the inside of the cylinder (130) or serration pressing, and can also be fixed to the cylinder (130) by a coupling method such as bolting or pinning to the inner surface of the cylinder (130).

[0127] Referring to FIG. 12, a piston (200) is inserted into a cylinder (130). A load smaller than the load applied to the retainer body part (510) in a second direction is applied to the piston boot (600) coupled to the piston body part (210) to press the piston boot (600) into the inside of the cylinder (130).

[0128] A vehicle brake device according to an embodiment of the present invention prevents rotation of the piston (200) by interfering with the fourth interference part (520) formed on the piston (200) and prevents rotation of the bolt screw (400) by interfering with the first interference part (220) formed on the piston (200) by the third interference part (430) formed on the bolt head part (420).

[0129] A vehicle brake device according to an embodiment of the present invention can maintain the centering of the piston (200) by applying the elastic force of a protrusion (531) formed on a damper part (530) toward the center of the piston (200) to the piston (200).

[0130] A vehicle brake device according to an embodiment of the present invention can maintain the sliding resistance of the piston (200) to a minimum by forming a stable lubricating film when the piston (200) moves, as the groove formed between a plurality of protrusions (531) acts as a grease (lubricant) pocket.

[0132] 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

[0133] 10: Carrier 11: Guide rod 20: Brake disc 30: Brake pad 100: Caliper body 110: Bridge 120: Finger 130: Cylinder 200: Piston 210: Piston body 220: 1st Interference Section 230: 2nd Interference Section 300: Nut screw 400: Bolt screw 410: Bolt body 420: Bolt head 421: Pressurizing section 430: Third interference section 500: Retainer 510: Retainer body 520: 4th Interference Section 530: Damper Section 531: Protrusion 600: Piston boot 700: Bearing

Claims

Claim 1 A brake device for a vehicle, comprising: a caliper body equipped with a cylinder; a nut screw rotatably disposed in the cylinder; a bolt screw movable in conjunction with the rotation of the nut screw in a first direction or in a second direction opposite to the first direction; a piston movably disposed in the cylinder, moved in the first direction by the pressure of the bolt screw, and interfering with the bolt screw to restrain the rotation of the bolt screw; and a retainer fixed to the cylinder and interfering with the piston to restrain the rotation of the piston; wherein the retainer comprises a damper portion coupled to a ring-shaped retainer body portion disposed between the cylinder and the piston and capable of contacting the piston. Claim 2 A vehicle brake device according to claim 1, wherein the piston comprises: a piston body portion into which the bolt screw is inserted; a first interference portion provided on the inner circumferential surface of the piston body portion and interfering with the bolt screw; and a second interference portion provided on the outer circumferential surface of the piston body portion and interfering with the retainer. Claim 3 A vehicle brake device according to claim 2, characterized in that the first interference part is formed protruding from the inner circumferential surface of the piston body part, and the second interference part is formed recessed from the outer circumferential surface of the piston body part. Claim 4 A vehicle brake device according to paragraph 3, characterized in that the second interference portion extends along the central axis direction of the piston. Claim 5 A vehicle brake device according to claim 2, wherein the bolt screw comprises: a bolt body portion coupled to the nut screw via a ball member; a bolt head portion that pressurizes the piston body portion; and a third interference portion provided on the outer surface of the bolt head portion and capable of contacting the first interference portion. Claim 6 A vehicle brake device according to claim 5, wherein the third interference portion is characterized by a portion of the outer surface of the bolt head portion being cut to form a flat plane. Claim 7 A vehicle brake device according to paragraph 2, wherein the retainer further comprises a fourth interference part provided on the inner circumferential surface of the retainer body part and capable of contacting the second interference part. Claim 8 A vehicle brake device according to claim 7, characterized in that the fourth interference portion is formed protruding from the inner circumference of the retainer body portion. Claim 9 delete Claim 10 A vehicle brake device according to claim 1, characterized in that the damper portion further comprises a projection portion that rests on the piston.

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