Drum brake apparatus

Patent metadata

Field	Value
Publication number	US-11891027-B2
Application number	US-202117356115-A
Country	US
Kind code	B2
Filing date	Jun 23, 2021
Priority date	Jun 23, 2020
Publication date	Feb 6, 2024
Grant date	Feb 6, 2024

Abstract

A drum brake apparatus includes a housing; a main braking unit installed on one part of the housing, and driven by a hydraulic pressure and pressing a shoe, during main braking; and a parking braking unit installed on the other part of the housing, and driven by an electromotive force of an actuator and pressing the shoe, during parking braking, the parking braking unit includes a bevel gear section disposed in the housing while having a structure of a bevel gear, and rotated in association with the actuator; and a rod section connected with the bevel gear section, and moved out of the housing in association with the bevel gear section and pressing the shoe.

First claim

What is claimed is:

1. A drum brake apparatus comprising:
a housing;
a main braking unit disposed on a first portion of the housing, the main braking unit configured to be, during main braking, driven by a hydraulic pressure and pressing a shoe; and
a parking braking unit disposed on a second portion of the housing, the parking braking unit configured to be, during parking braking, driven by an electromotive force of an actuator and to press the shoe,
the parking braking unit comprising:
a bevel gear section disposed in the housing, the bevel gear section configured to rotate in association with the actuator, the bevel gear section comprising:

a driving gear connected with the actuator; and
a driven gear meshed with the driving gear; and
a rod section connected with the bevel gear section, the rod section disposed to be reciprocating in and out of the housing in association with the bevel gear section while pressing the shoe, the rod section comprising:
a rotation rod connected with the driven gear, wherein external threads are disposed on an outer surface of the rotation rod to be symmetrical to each other based on the driven gear,

wherein the main braking unit is disposed closer to a rotation center of a back plate than the parking braking unit.

2. The drum brake apparatus according to claim 1 , wherein the
driven gear is disposed on the same horizontal line as the driving gear, and threadedly coupled with the rod section via the rotation rod.

3. The drum brake apparatus according to claim 2 , wherein the driving gear is disposed parallel to the rotation center of the back plate, and
wherein the driven gear is disposed on a same radial extension line as the main braking unit with respect to the rotation center of the back plate.

4. The drum brake apparatus according to claim 2 , wherein the rod section further comprises:
a push rod threadedly coupled around the rotation rod, and disposed to be reciprocating in and out of the housing in association with rotation of the rotation rod, and
wherein the rotation rod is connected with the driven gear on a same shaft.

5. The drum brake apparatus according to claim 1 , wherein the housing comprises a housing body which includes:
a piston receiving body at a first side of the housing body, the piston receiving body having a hollow structure in which the main braking unit is disposed; and
a rod receiving body at a second side of the housing body, the rod receiving body having a hollow structure in which the parking braking unit is disposed.

6. The drum brake apparatus according to claim 5 , wherein the housing body further comprises:
a body part integrally connected with the piston receiving body and the rod receiving body;
a fastening part disposed on the body part to be fastened to the back plate; and
a foreign matter introduction prevention part configured to be coupled to a side of the body part having openings of the piston receiving body and the rod receiving body, the foreign matter introduction prevention part configured to cover an edge portion of the piston receiving body and an edge portion of the rod receiving body.

7. The drum brake apparatus according to claim 6 , wherein the fastening part comprises:
a fastening locking portion defined at each side of the body part, and configured to be fastened to the back plate together with the actuator by a locking member; and
a movement preventing portion protruding on the body part so as to correspond to the main braking unit and extend through a through hole of the back plate.

8. The drum brake apparatus according to claim 6 , wherein the foreign matter introduction prevention part comprises:
a sealing cover disposed to cover a side of the body part;
a piston sealing portion having a hollow structure at a first side of the sealing cover, an edge of the piston sealing portion connected with the main braking unit;
a rod sealing portion having a hollow structure at a second side of the sealing cover, an edge of the rod sealing portion connected with the parking braking unit; and
a body fixing portion continuously disposed along the edge of the sealing cover and fixedly connected to the body part.

9. The drum brake apparatus according to claim 5 , wherein the piston receiving body comprises:
a cylinder, having a circular space, disposed in the housing body and accommodating the main braking unit; and
a hydraulic flow path, through which a fluid is supplied into the cylinder, extending from an outer surface of the housing body to the cylinder.

10. The drum brake apparatus according to claim 5 , wherein the rod receiving body comprises:
a rod cylinder, having a circular space, disposed in the housing body and accommodating the parking braking unit; and
a driving shaft receiving part, through which an output shaft of the actuator extends and is connected to the parking braking unit, disposed at a predetermined distance from the piston receiving body and communicating with the rod cylinder part.

11. The drum brake apparatus according to claim 5 , wherein the piston receiving body and the rod receiving body are disposed on the same radial extension line with respect to the rotation center of the back plate, and
wherein the actuator, which is disposed parallel to the rotation center of the back plate, is disposed on the same radial extension line as a chassis which is configured to support a center portion of the back plate.

12. The drum brake apparatus according to claim 1 , wherein the main braking unit comprises:
a piston disposed at an end of the housing, and configured to reciprocate in and out of the housing by a hydraulic pressure so as to press the shoe; and
an elastic member disposed in the housing, the elastic member configured to reduce an impact force applied to the piston returning into the housing.

13. The drum brake apparatus according to claim 2 , wherein the drum brake apparatus includes a first row corresponding to a rotation axis of the main braking unit and a second row corresponding to rotation axes of the driving gear and the driven gear.

14. The drum brake apparatus according to claim 1 , wherein the driven gear and the rotation rod are integrally connected.

Assignees

• Hyundai Mobis Co Ltd

Inventors

• Jo Chi Hoon
• Kim Byeung Su

Classifications

• B60T13/588 Primary

  both fluid and mechanical assistance or drive · CPC title

• B60T13/746

  and mechanical transmission of the braking action · CPC title

• F16D65/22

  adapted for pressing members apart {, e.g. for drum brakes} · CPC title

• B60T1/067

  employing drum (B60T1/062 takes precedence) · CPC title

• F16D51/22

  mechanically actuated · CPC title