EP-4737757-A1 - BRAKE APPARATUS FOR VEHICLE

EP4737757A1EP 4737757 A1EP4737757 A1EP 4737757A1EP-4737757-A1

Abstract

A brake apparatus for a vehicle includes: a caliper body provided with a cylinder; a nut screw rotatably disposed on the cylinder; a bolt screw 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

BOO, SANG PIL
SHIN, CHOONG SIK
JEON, DAE UNG
YOON, Bo Ram
PARK, SANG JUN
BYOUN, MUN HWAN

Assignees

Hyundai Mobis Co., Ltd.

Dates

Publication Date: 20260506
Application Date: 20250225

Claims (10)

A brake apparatus for a vehicle, the brake apparatus comprising: a caliper body provided with a cylinder; a nut screw rotatably disposed on the cylinder; a bolt screw 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 brake apparatus for the vehicle of claim 1, wherein the piston comprises: a piston body portion into which the bolt screw is inserted; a first interference portion provided on an inner peripheral surface of the piston body portion and configured to interfere with the bolt screw; and a second interference portion provided on an outer peripheral surface of the piston body portion and configured to interfere with the retainer.
The brake apparatus for the vehicle of claim 2, wherein: the first interference portion is formed to protrude from the inner peripheral surface of the piston body portion, and the second interference portion is formed to be recessed on the outer peripheral surface of the piston body portion.
The brake apparatus for the vehicle of claim 2 or 3, wherein the second interference portion extends along a central axis of the piston.
The brake apparatus for the vehicle of any one of claims 2 to 4, wherein the bolt screw comprises: a bolt body portion coupled to the nut screw by means of a ball member; 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 brake apparatus for the vehicle of claim 5, wherein the third interference portion is formed as a flat surface by cutting off a portion of the outer peripheral surface of the bolt head portion.
The brake apparatus for the vehicle of any one of claims 2 to 6, wherein the retainer comprises: a retainer body portion, in a ring shape, 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 brake apparatus for the vehicle of claim 7, wherein the fourth interference portion is formed to protrude from the inner peripheral surface of the retainer body portion.
The brake apparatus for the vehicle of claim 7 or 8, wherein the retainer further comprises a damper portion coupled to the retainer body portion and capable of coming into contact with the piston.
The brake apparatus for the vehicle of claim 9, wherein the damper portion is further provided with a projection portion seated on the piston.

Description

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 April 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 provided with a cylinder; a nut screw rotatably disposed on the cylinder; a bolt screw 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 provided on an inner peripheral surface of the piston body portion and configured to interfere with the bolt screw; and a second interference portion provided on an outer peripheral surface of the piston body portion and configured to interfere 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 coupled to the nut screw by means of a ball member; 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, in a ring shape, 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 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 piston, thereby maintaining the centering of the piston. With the present disclosure, a groove formed between a plurality of the projection portions may act as a grease (lubricant) pocket to form a stable lubrication film when the piston moves, thereby minimizing frictional resistance of the piston. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a brake apparatus