Motor-driven steering column device for vehicle

1. A motor-driven steering column device for a vehicle, the motor-driven steering column device comprising:

a housing fixed to a vehicle body and having a pipe through one side portion of which a slot is formed;

a telescopic pipe inserted into an internal diameter portion of the housing to be movable back and firth and locked and fastened to a steering shaft;

a telescopic bracket disposed on an internal diameter portion of the telescopic pipe; and

a driving device coupling the telescopic pipe and the telescopic bracket through the slot and providing power of moving back and forth to the telescopic pipe and the telescopic bracket,

wherein the telescopic bracket includes:

arched portion plates in contact with an internal diameter surface of the telescopic pipe;

straight portion plates distanced from the internal diameter surface of the telescopic pipe, which are integrally and repeatedly formed together in a circumferential direction thereof; and

an internal thread hole formed on one end portion of the telescopic bracket.

2. The motor-driven steering column device of claim 1 , wherein the straight portion plates of the telescopic bracket have a guide hole inside, through which a bending plate is inserted.

3. The motor-driven steering column device of claim 1 , wherein the slot is long to limit movements of the telescopic pipe and the telescopic bracket and extends in a front and rear direction thereof.

4. The motor-driven steering column device of claim 1 , wherein the driving device includes:

a motor mounted on an external diameter portion of the housing;

a screw connected to an output shall of the motor;

a back and forth moving block into which the screw is inserted and fastened to be rotatable; and

a bolt fastened to an internal thread hole of the telescopic bracket from the back and forth moving block and coupling the telescopic bracket and the telescopic pipe with each other.

5. The motor-driven steering column device of claim 4 , wherein the bolt has a telescopic bushing attached to a head portion thereof, the bushing being a material contactable with an outer circumferential surface of the slot of the housing to slip on the outer circumferential surface of the slot.

6. The motor-driven steering column device of claim 4 , wherein the bolt has a collision absorbing bushing attached to a bottom portion thereof, the collision absorbing bushing tightening and attaching the telescopic pipe to the telescopic bracket.

7. The motor-driven steering column device of claim 1 , further including:

a bending plate including a straight plate of which a first end portion is fixed to an internal diameter end portion of the telescopic pipe, and a restriction plate having a curved cross section which extends from a second end portion of the straight plate, passes through a guide hole of the telescopic bracket, extends toward a rear end portion of the telescopic bracket.

8. The motor-driven steering column device of claim 7 , wherein the straight plate of the bending plate is disposed straight in a space of the telescopic bracket where the straight portion plates and the telescopic pipe are distanced from each other.

9. The motor-driven steering column device of claim 7 , wherein the restriction plate of the bending plate has a curved cross section formed convexly outward, and wherein the restriction plate is disposed to be in friction contact with an internal surface of the straight portion plates of the telescopic bracket.

10. The motor-driven steering column device of claim 1 , wherein the external diameter surface of the telescopic pipe has at least three load support structures protruded at an equal interval in a circumferential direction thereof.

11. The motor-driven steering column device of claim 10 , wherein the load support structures are concentratedly formed on the internal diameter surface of the housing, and are wide toward a rear end portion from a front end portion thereof.