Steer-by-wire type power steering apparatus

1. A steer-by-wire type power steering apparatus comprising:

a cylinder provided inside a housing and comprising a first spline on an inner circumferential surface of the cylinder; and

a sliding bar inserted into the cylinder and comprising a second spline engaged with the first spline and first and second screws, wherein the second spline of the sliding bar is disposed between the first screw and the second screw of the sliding bar,

wherein the sliding bar comprises an anti-rotation bar comprising the second spline and at least one screw bar comprising the first and second screws.

2. The steer-by-wire type power steering apparatus of claim 1 , wherein:

the first screw of the sliding bar is disposed adjacent to one end of the second spline of the sliding bar, and the second screw of the sliding bar is disposed adjacent to another end of the second spline of the sliding bar, and

screw directions of the first screw and the second screw of the sliding bar are formed in different directions from each other.

3. The steer-by-wire type power steering apparatus of claim 1 , wherein any one of the anti-rotation bar and the screw bar comprises an engagement groove recessed in an axial direction and a remaining one comprises an engagement part inserted into the engagement groove.

4. The steer-by-wire type power steering apparatus of claim 3 , wherein the engagement part is screwed to the engagement groove, press-fitted to the engagement groove, or screwed and press-fitted to the engagement groove.

5. The steer-by-wire type power steering apparatus of claim 1 ,

wherein one or more motors comprise a first motor connected to the first screw via a first gear box and a second motor connected to the second screw via the second gear box.

6. The steer-by-wire type power steering apparatus of claim 5 , wherein a screw direction of the first screw and a screw direction of the second screw are opposite each other.

7. The steer-by-wire type power steering apparatus of claim 5 , further comprising:

a sliding bar positioner that determines a moving position of the sliding bar based on first rotation information, which is rotation information of the first motor or the first gear box, and a moving position of the sliding bar based on second rotation information, which is rotation information of the second motor or the second gear box,

wherein the first motor and the sliding bar have a first reduction ratio, and the second motor and the sliding bar have a second reduction ratio different from the first reduction ratio.

8. The steer-by-wire type power steering apparatus of claim 7 , wherein the first rotation information and the second rotation information are phase information, and

wherein the sliding bar positioner determines the moving position of the sliding bar based on a phase difference between the first rotation information and the second rotation information.

9. The steer-by-wire type power steering apparatus of claim 8 , wherein the sliding bar positioner comprises a rotation information receiver configured to receive the first rotation information and the second rotation information, a rotation information monitor configured to monitor a change in the first rotation information and the second rotation information, and a positioner configured to determine the moving position of the sliding bar based on a monitoring result.

10. The steer-by-wire type power steering apparatus of claim 9 , wherein the rotation information monitor monitors the phase difference and a number of times the phase difference becomes zero (0).

11. A steer-by-wire type power steering apparatus comprising:

a cylinder provided inside a housing and comprising a first spline on an inner circumferential surface of the cylinder, and

a sliding bar inserted into the cylinder and comprising a second spline engaged with the first spline and first and second screws,

wherein:

the second spline of the sliding bar is disposed between the first screw and the second screw of the sliding bar,

a first motor is connected to the first screw of the sliding bar, and

a second motor is connected to the second screw of the sliding bar.

12. A steer-by-wire type power steering apparatus comprising:

a cylinder disposed inside a housing and comprising a first spline on an inner circumferential surface of the cylinder; and

a sliding bar inserted into the cylinder and comprising a second spline engaged with the first spline, the sliding bar having screw bars configured to be slidable in an axial direction by one or more motors to steer one or more wheels,

wherein:

at least one of the screw bars is connected to a ball nut configured to be rotated by the one or more motors,

the screw bars comprise a first screw bar positioned adjacent to one end of the second spline of the sliding bar and a second screw bar positioned adjacent to another end of the second spline of the sliding bar, and

a screw of the first crew bar and a screw of the second screw bar are formed in different directions from each other.

13. The steer-by-wire type power steering apparatus of claim 1 , further comprising a sliding bar positioner configured to receive first rotation information of a first motor or a first gear box connected to the first screw and second rotation information of a second motor or a second gear box connected to the second crew, monitor a change in the first rotation information and the second rotation information, and determine a moving position of the sliding bar based on a monitoring result.