Parking brake apparatus for vehicle

1. A parking brake apparatus for a vehicle, comprising:

a motor section receiving electric power from an outside, and generating power;

a power transmission section rotated by driving the motor section;

a pair of pressing units having rotation axes that are disposed parallel to a rotation axis of the power transmission section, and pressing a brake pad by receiving power from the power transmission section; and

a load transmission unit installed between the pair of pressing units, connected to each of the pair of pressing units, and transmitting a pressing load of any one of the pair of pressing units to the other pressing unit,

wherein each of the pair of pressing units comprises:

a sun gear section rotated by receiving power from the driving unit;

a planetary gear section rotated by being meshed with the sun gear section; and

a piston section pressing the brake pad by being moved toward the brake pad through receiving rotational power from the planetary gear section,

wherein the load transmission unit comprises a pair of ring gear sections,

wherein each of the pair of ring gear sections is rotatable by being meshed with the planetary gear section, and

wherein the pair of ring gear sections are directly or indirectly meshed with each other,

wherein the power transmission section comprises a power transmission gear which has a rotation axis parallel to a rotation axis of the sun gear section, and

wherein the power transmission gear is meshed with a driving gear of the motor section, receives power from the motor section, and transmits power to the sun gear section through a connection gear section.

2. The parking brake apparatus of claim 1 , wherein each of the pair of pressing units further comprises a carrier section coupled to the planetary gear section, wherein the piston section is connected to the carrier section.

3. The parking brake apparatus of claim 1 , wherein the connection gear section comprises:

a connection gear body coupled to the sun gear section; and

a connection gear formed on an outer circumference surface of the connection gear body, and meshed with the power transmission gear.

4. The parking brake apparatus of claim 3 ,

wherein the connection gear section further comprises a connecting insertion part formed in a space inside a wall on which the connection gear is formed, and

wherein the ring gear section is inserted into and disposed in the connecting insertion part.

5. The parking brake apparatus of claim 4 , wherein a rotation center of the sun gear section is concentric with a rotation center of the connection gear section.

6. The parking brake apparatus of claim 3 , wherein the power transmission section is disposed at a middle between the connection gear of any one of the pair of pressing units and the connection gear of the other of the pair of pressing units.

7. The parking brake apparatus of claim 2 , wherein each of the pair of ring gear sections comprises:

a ring gear inner part formed with an internal gear portion on an inner circumferential surface thereof to be meshed with the planetary gear section; and

a ring gear outer part coupled to an outer surface of the ring gear inner part, and formed with an external gear portion on an outer circumferential surface thereof.

8. The parking brake apparatus of claim 7 , wherein the ring gear inner part projects more toward the sun gear section than the ring gear outer part, and surrounds the sun gear section and the planetary gear section.

9. The parking brake apparatus of claim 2 , wherein the carrier section is spline-coupled to the piston section.

10. The parking brake apparatus of claim 9 , wherein the piston section receives rotational power from the carrier section, and is linearly reciprocated relative to the brake pad depending on a rotating direction of the carrier section.

11. A parking brake apparatus for a vehicle, comprising:

a motor section receiving electric power from an outside, and generating power;

a power transmission section including a transmission belt, and rotated as driving of the motor section is transmitted by the transmission belt;

a pair of pressing units receiving power from the power transmission section and pressing a brake pad; and

a load transmission unit installed between the pair of pressing units, connected to each of the pair of pressing units, and transmitting a pressing load of any one of the pair of pressing units to the other pressing unit,

wherein each of the pair of pressing units comprises:

a sun gear section rotated by receiving power from the power transmission section;

a planetary gear section rotated by being meshed with the sun gear section; and

a piston section pressing the brake pad by being moved toward the brake pad through receiving rotational power from the planetary gear section, wherein the power transmission section comprises:

a transmission shaft dynamically connected to the motor section by the transmission belt; and

transmission worm gears disposed at both sides of the transmission shaft, and each transmitting a rotational force of the transmission shaft to the sun gear section.

12. The parking brake apparatus of claim 11 , wherein each of the pair of pressing units further comprises a carrier section coupled to the planetary gear section, wherein the piston section is connected to the carrier section.

13. The parking brake apparatus of claim 12 , wherein each transmission worm gear transmits power to the sun gear section through a connection gear section.