Steer-by-wire steering apparatus
According to the embodiments of the present invention, the overall size reduction allows installation space to be advantageously secured, reduction in noise generated during operation improves the comfort of the driver, and the strength and stability of the connective structure between parts can be increased and power transmission can be more effective.
1. A steer-by-wire steering device, comprising:
a sliding bar provided to be axially slidable in a housing and having a screw formed on an outer circumferential surface thereof;
a first shaft hollow to allow the sliding bar to be inserted thereto and rotated by an actuator;
a plurality of second shafts circumferentially provided between the sliding bar and the first shaft and including a screw shaft portion having a screw formed on an outer circumferential surface thereof to be engaged with the sliding bar; and
a supporting member formed in an annular shape to be coupled to an inner circumferential surface of the first shaft and having a coupling hole through which an end of the second shaft is inserted and coupled.
2. The steer-by-wire steering device of claim 1 , wherein two supporting members are provided to be coupled to two opposite ends of the first shaft.
3. The steer-by-wire steering device of claim 1 , wherein the second shaft includes a supporting shaft portion supported on the inner circumferential surface of the first shaft.
4. The steer-by-wire steering device of claim 3 , wherein a mountain portion and a valley portion engaged with each other are formed on an outer circumferential surface of the supporting shaft portion and the inner circumferential surface supported on the supporting shaft portion of the first shaft.
5. The steer-by-wire steering device of claim 3 , wherein supporting shaft portions are provided on two opposite ends of the second shaft.
6. The steer-by-wire steering device of claim 3 , wherein two or more screw shaft portions are provided to be spaced apart from each other, and wherein the supporting shaft portion is provided between the screw shaft portions.
7. The steer-by-wire steering device of claim 3 , wherein the screw shaft portion has a larger diameter than the supporting shaft portion.
8. The steer-by-wire steering device of claim 1 , wherein a bearing is coupled between the housing and the first shaft.
9. The steer-by-wire steering device of claim 1 , wherein the actuator includes a stator coupled to an inner circumferential surface of the housing and a rotator hollow to allow the sliding bar to be inserted thereto and rotated, together with the first shaft.
10. The steer-by-wire steering device of claim 9 , wherein the first shaft includes a coupling portion formed by diameter expansion at the outer circumferential surface thereof, and
wherein the first shaft and the rotator are coupled by a coupling member axially passing through the coupling portion and coupled by the rotator.
11. The steer-by-wire steering device of claim 9 , wherein the rotator is integrally formed with the first shaft.
12. The steer-by-wire steering device of claim 1 , wherein a bushing member is coupled between the housing and the sliding bar, and wherein a first flat portion formed to be chamfered is provided on an outer circumferential surface of the sliding bar, and a second flat portion supported on the first flat portion is provided on an inner circumferential surface of the bushing member.
13. The steer-by-wire steering device of claim 12 , wherein an insertion portion radially protruding is formed on an outer circumferential surface of the bushing member, and an insertion recess to which the insertion portion is inserted is depressed in the inner circumferential surface of the housing.
14. The steer-by-wire steering device of claim 1 , further comprising a worm wheel gear engaged with the screw of the sliding bar, wherein a position of the sliding bar is sensed from a rotation angle of the worm wheel gear.
15. The steer-by-wire steering device of claim 14 , wherein a circumference of the worm wheel gear is longer than a maximum stroke of the sliding bar.