US-20260126088-A1 - BRAKE APPARATUS FOR VEHICLE

US20260126088A1US 20260126088 A1US20260126088 A1US 20260126088A1US-20260126088-A1

Abstract

A brake apparatus for a vehicle includes: a caliper body including a cylinder; a nut screw rotatably engaged to the cylinder; a bolt screw engaged to the nut screw and movable in a first direction or in a second direction opposite to the first direction in conjunction with rotation of the nut screw; a piston movably disposed in the cylinder and configured to move in the first direction by pressurization of the bolt screw and interfere with the bolt screw to restrict rotation of the bolt screw; and a retainer secured to the cylinder and configured to interfere with the piston to restrict rotation of the piston.

Inventors

Sang Pil BOO
Choong Sik Shin
Dae Ung Jeon
Bo Ram Yoon
Sang Jun Park
Mun Hwan BYOUN

Assignees

HYUNDAI MOBIS CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20250325
Priority Date: 20241104

Claims (16)

1 . A brake apparatus for a vehicle, the brake apparatus comprising: a caliper body including a cylinder; a nut screw rotatably engaged to the cylinder; a bolt screw engaged to the nut screw and movable in a first direction or in a second direction opposite to the first direction in conjunction with rotation of the nut screw; a piston movably disposed in the cylinder and configured to move in the first direction by pressurization of the bolt screw and interfere with the bolt screw to restrict rotation of the bolt screw; and a retainer secured to the cylinder and configured to interfere with the piston to restrict rotation of the piston.
2 . The brake apparatus of claim 1 , wherein the piston includes: a piston body portion into which the bolt screw is inserted; a first interference portion disposed on an inner peripheral surface of the piston body portion and interfering with the bolt screw; and a second interference portion provided on an outer peripheral surface of the piston body portion and interfering with the retainer.
3 . The brake apparatus of claim 2 , wherein the piston body portion is linearly movable along the first and second interference portions in the first direction or the second direction in conjunction with rotation of the nut screw.
4 . The brake apparatus of claim 2 , wherein the first interference portion protrudes inwards from the inner peripheral surface of the piston body portion, and wherein the second interference portion is recessed inwards on the outer peripheral surface of the piston body portion.
5 . The brake apparatus of claim 4 , wherein the first interference portion extends along a central axis of the piston.
6 . The brake apparatus of claim 4 , wherein the second interference portion extends along a central axis of the piston.
7 . The brake apparatus of claim 2 , wherein the bolt screw includes: a bolt body portion rotatably coupled to the nut screw; a bolt head portion configured to pressurize the piston body portion; and a third interference portion formed on an outer peripheral surface of the bolt head portion and capable of slidably coming into contact with the first interference portion.
8 . The brake apparatus of claim 7 , wherein the bolt body portion is rotatably coupled to the nut screw by a ball member disposed between the bolt body portion and the nut screw.
9 . The brake apparatus of claim 7 , wherein the third interference portion is formed as a flat surface by cutting off a portion of an outer peripheral surface of the bolt head portion.
10 . The brake apparatus of claim 7 , wherein the nut screw includes: a first portion disposed adjacent to the bolt head portion in the first direction; and a second portion disposed opposite to the first portion in the second direction, wherein an outer diameter of the first portion is larger than an outer diameter of the second portion, and wherein a bearing is mounted between the first portion and the second portion to rotatably support the nut screw inside the cylinder.
11 . The brake apparatus of claim 2 , wherein the retainer includes: a retainer body portion being in an annular shape and disposed between the cylinder and the piston; and a fourth interference portion disposed on an inner peripheral surface of the retainer body portion and seated inside the second interference portion.
12 . The brake apparatus of claim 11 , wherein the fourth interference portion protrudes inwards from the inner peripheral surface of the retainer body portion.
13 . The brake apparatus of claim 11 , wherein the retainer further includes a damper portion coupled to the retainer body portion and slidably contacting with the piston.
14 . The brake apparatus of claim 13 , wherein the damper portion includes a projection portion slidably seated on the piston.
15 . The brake apparatus of claim 13 , wherein the projection portion is in plural and a groove is formed between the plurality of the projection portions to act as a lubricant pocket.
16 . The brake apparatus of claim 1 , further including a piston boot disposed between the cylinder and the piston.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority from and the benefit under 35 USC § 119 of Korean Patent Application No. 10-2024-0154338, filed on Nov. 4, 2024, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated by reference for all purposes. BACKGROUND Field Exemplary embodiments of the present disclosure relate to a brake apparatus for a vehicle, and more particularly, to a brake apparatus for a vehicle, which may ensure stable braking performance. Description of the Related Art In general, a vehicle brake apparatus pushes a piston through a driving force to bring a pad and a disc into close contact, and uses a friction force between the pad and the disc to brake a vehicle. Among vehicle brake apparatuses, an electro mechanical brake (EMB) does not use hydraulic pressure, but instead has a motor-driven actuator mounted on a caliper, pressurizing a piston to generate a braking force through a mechanism that converts a rotational motion of a screw into a linear motion of a nut or converts a rotational motion of the nut into a linear motion of the screw. The EMB is capable of active braking and independent braking for each wheel, thereby enabling not only general primary braking but also the implementation of each of the additional functions such as an anti-lock brake system (ABS), electric stability control (ESC), a traction control system (TCS), and automatic emergency braking (AEB), and the absence of hydraulic transmission delay enables higher performance. The related art of the present disclosure is disclosed in Korean Patent Application Publication No. 10-2024-0054695 (published on Apr. 26, 2024 and entitled “BRAKE APPARATUS FOR VEHICLE”). SUMMARY An objective of the present disclosure is to provide a brake apparatus for a vehicle, which may ensure stable braking performance. A brake apparatus for a vehicle according to the present disclosure includes: a caliper body including a cylinder; a nut screw rotatably engaged to the cylinder; a bolt screw engaged to the nut screw and movable in a first direction or in a second direction opposite to the first direction in conjunction with rotation of the nut screw; a piston movably disposed in the cylinder and configured to move in the first direction by pressurization of the bolt screw and interfere with the bolt screw to restrict rotation of the bolt screw; and a retainer secured to the cylinder and configured to interfere with the piston to restrict rotation of the piston. The piston may include: a piston body portion into which the bolt screw is inserted; a first interference portion disposed on an inner peripheral surface of the piston body portion and interfering with the bolt screw; and a second interference portion provided on an outer peripheral surface of the piston body portion and interfering with the retainer. The first interference portion may be formed to protrude from the inner peripheral surface of the piston body portion, and the second interference portion may be formed to be recessed on the outer peripheral surface of the piston body portion. The second interference portion may extend along a direction parallel to the first direction and the second direction. The bolt screw may include: a bolt body portion rotatably coupled to the nut screw by a ball member disposed between the bolt body portion and the nut screw; a bolt head portion configured to pressurize the piston body portion; and a third interference portion provided on an outer peripheral surface of the bolt head portion and capable of coming into contact with the first interference portion. The third interference portion may be formed as a flat surface by cutting off a portion of the outer peripheral surface of the bolt head portion. The retainer may include: a retainer body portion being in an annular shape and disposed between the cylinder and the piston; and a fourth interference portion provided on an inner peripheral surface of the retainer body portion and capable of coming into contact with the second interference portion. The fourth interference portion may be formed to protrude from the inner peripheral surface of the retainer body portion. The retainer further may include a damper portion coupled to the retainer body portion and capable of coming into contact with the piston. The damper portion may be further provided with a projection portion slidably seated on the piston. With the present disclosure, the second interference portion formed on the piston interferes with the fourth interference portion formed on the retainer, thereby preventing the rotation of the piston, and the third interference portion formed on the bolt head portion interferes with the first interference portion formed on the piston, thereby preventing the rotation of the bolt screw. With the present disclosure, an elastic force of the projection portion formed on the damper portion is applied to the piston toward a central portion of the