Electro-mechanical brake and vehicle comprising the same

1. An electro-mechanical brake comprising a pair of brake pads disposed on both sides of a disc, comprising:

a motor that provides a rotational driving force;

a rotating screw that rotates about a second rotating shaft parallel to a first rotating shaft of the motor;

a power transmission unit that transmits the rotational driving force of the motor to the rotating screw;

a piston that is coupled to the rotating screw to be able to move forward and backward to press the disc with the brake pads; and

a ball nut that is coupled to the rotating screw,

wherein the power transmission unit includes a first gear coupled to the first rotating shaft of the motor, a second gear coupled to the second rotating shaft of the rotating screw, and a third gear engaging with the first gear and the second gear and rotating about a third rotating shaft spaced apart from a plane including the first rotating shaft and the second rotational shaft,

the rotating screw includes a first body portion to which the ball nut is coupled, a second body portion formed behind the first body portion and coupled to the second gear, and a third body portion formed between the first body portion and the second body portion,

the piston is formed in a cup shape with an opening at a rear thereof,

the ball nut is inserted into the opening of the piston to press the piston forward,

the first body portion, the third body portion, and the second body portion are formed such that a size of a cross-section perpendicular to a longitudinal direction is sequentially decreased,

wherein the electro-mechanical brake comprises a supporter that is disposed on an outer peripheral surface of the third body portion and includes a front surface supported on an edge portion of a rear end of the first body portion, and

an elastic that includes one side coupled to the supporter and the other side coupled to the ball nut to pull the ball nut toward the supporter.

2. The electro-mechanical brake according to claim 1 , further comprising a planetary gear structure that includes one side coupled to a rear end of the rotating screw,

wherein the second gear is coupled to the other side of the planetary gear structure.

3. The electro-mechanical brake according to claim 1 , wherein the first gear, the second gear and the third gear are helical gears.

4. The electro-mechanical brake according to claim 1 , further comprising a connector that is formed to surround a front end of the ball nut in order to be pressed forward by the ball nut, and includes a first screw thread formed on an outer peripheral surface thereof,

wherein a second screw thread screw-coupled to the first screw thread is formed on an inner peripheral surface of the piston.

5. The electro-mechanical brake according to claim 4 , wherein an inclined surface is formed on a front edge portion of the ball nut along a circumference,

a support surface corresponding to the inclined surface is formed on an inner peripheral surface of a front side of the connector so as to be pressed by the inclined surface.

6. The electro-mechanical brake according to claim 1 , wherein the elastic is formed in a spiral shape surrounding outer peripheral surfaces of the ball nut and the supporter.

7. The electro-mechanical brake according to claim 6 , further comprising a thrust bearing disposed at a rear of the supporter to support a load according to an axial force of the rotating screw.

8. The electro-mechanical brake according to claim 1 , further comprising a rotation preventing unit that controls the third gear to rotate in only one direction.

9. The electro-mechanical brake according to claim 8 , wherein the rotation preventing unit includes a latch to be inserted into a first space formed on one side of the third gear,

the third gear is in a locked state in which the third gear is rotated in only one direction when the latch is inserted into the first space, and the third gear is in an unlocked state in which the third gear is rotated in both directions when the latch is separated from the first space.

10. The electro-mechanical brake according to claim 9 , wherein the latch is fixed to be pivotally rotatable,

the rotation preventing unit further includes a plurality of protrusions continuously formed along a circumference of the third gear on one side of the third gear, and an actuator for controlling pivot rotation of the latch, and

the first space is formed in plurality between the plurality of protrusions.

11. The electro-mechanical brake according to claim 10 , wherein one side of the plurality of protrusions in a circumferential direction of the third gear is provided with a guide surface formed to be inclined.

12. A vehicle provided with an electro-mechanical brake, comprising:

the electro-mechanical brake according to claim 9 ;

a wheel to which the disc is coupled to one side so that the rotating shafts coincide; and

the pair of brake pads that is disposed on both sides of the disc and coupled to the electromechanical brake,

wherein in a driving state, a rotation speed of the wheel is controlled by pressing the disc with the brake pads while the unlocked state is maintained,

in a parking state, the locked state is maintained while the disc is pressed with the brake pads.