Electrically adjustable steering column

1. An electrically adjustable steering column comprising:

a top bracket attached to a vehicle body;

a steering shaft to which a steering wheel is connected;

a steering jacket held by the top bracket and configured to rotatably support the steering shaft on an inner side; and

an actuator configured to adjust lengths of the steering shaft and the steering jacket,

wherein the steering jacket includes a first jacket member and a second jacket member in this order from a side proximal to the steering wheel, and the first jacket member and the second jacket member overlap each other such that the steering jacket is extendable and retractable in an axial direction,

wherein the actuator is connected to an extension bracket that is attached to an outer surface of the first jacket member and extends toward the front of the vehicle body, so as to extend and retract the first jacket member with respect to the second jacket member,

wherein the extension bracket is attached to an outer surface of the first jacket member on the side proximal to the steering wheel and extends toward the front of the vehicle body,

wherein the second jacket member includes a guide portion configured to guide movement of the extension bracket,

wherein the guide portion holds the extension bracket so as to prevent rotation and movement in a radial direction of the extension bracket with respect to an axis of the electrically adjustable steering column,

wherein the actuator includes a motor, a screw shaft rotationally driven by the motor, and a nut to be screwed to the screw shaft to move on the screw shaft, and

wherein the extension bracket slidably contacts the guide portion and is coupled to the nut.

2. The electrically adjustable steering column according to claim 1 ,

wherein the actuator is provided between the top bracket and the first jacket member, and a motor of the actuator is fixed to the top bracket.

3. The electrically adjustable steering column according to claim 1 ,

wherein the actuator is provided between the first jacket member and the second jacket member, and a motor of the actuator is fixed to the second jacket member.

4. The electrically adjustable steering column according to claim 1 ,

wherein the extension bracket extends in the axial direction at a position offset from a straight line connecting a coupling point between the actuator and the top bracket or between the actuator and the second jacket member and a coupling point between the actuator and the extension bracket.

5. The electrically adjustable steering column according to claim 1 ,

wherein the steering shaft includes a first shaft member and a second shaft member in this order from the side proximal to the steering wheel, and the first shaft member and the second shaft member overlap each other such that the steering shaft is extendable and retractable in an axial direction.

6. An electrically adjustable steering column comprising:

a top bracket attached to a vehicle body;

a steering shaft to which a steering wheel is connected;

a steering jacket held by the top bracket and configured to rotatably support the steering shaft on an inner side; and

an actuator configured to adjust lengths of the steering shaft and the steering jacket,

wherein the steering jacket includes a first jacket member and a second jacket member in this order from a side proximal to the steering wheel, and the first jacket member and the second jacket member overlap each other such that the steering jacket is extendable and retractable in an axial direction,

wherein the actuator is connected to an extension bracket that is attached to an outer surface of the first jacket member and extends toward the front of the vehicle body, so as to extend and retract the first jacket member with respect to the second jacket member,

wherein the actuator includes a motor disposed on the top bracket or the second jacket member, a screw shaft rotationally driven by the motor, and a nut to be screwed to the screw shaft to move on the screw shaft, and

wherein at least one of a breaking mechanism configured to separate the extension bracket and the nut and a load generating mechanism configured to generate an energy absorbing load is provided on the extension bracket or between the extension bracket and the nut.

7. An electrically adjustable steering column comprising:

a top bracket attached to a vehicle body;

a steering shaft to which a steering wheel is connected;

a steering jacket held by the top bracket and configured to rotatably support the steering shaft on an inner side; and

an actuator configured to adjust lengths of the steering shaft and the steering jacket,

wherein the steering jacket includes a first jacket member and a second jacket member in this order from a side proximal to the steering wheel, and the first jacket member and the second jacket member overlap each other such that the steering jacket is extendable and retractable in an axial direction,

wherein the actuator is connected to an extension bracket that is attached to an outer surface of the first jacket member and extends toward the front of the vehicle body, so as to extend and retract the first jacket member with respect to the second jacket member, and

wherein the extension bracket has a deformation starting point causing the extension bracket to deform in a predetermined direction in a radial direction at the time of a vehicle collision.