Step device for vehicle

1. A step device for a vehicle, the step device comprising:

a movable step supported under a door opening;

a coupling member that, in a state of being supported by a sliding door that moves in a vehicle front-rear direction with a shifting zone in a vehicle width direction, engages with the movable step to move the movable step in the vehicle width direction in conjunction with opening and closing of the sliding door;

a support arm that has a first pivot-joint point relative to a vehicle body and a second pivot-joint point relative to the movable step, and supports the movable step toward an upper side; and

a cover member that is fixed to a lower surface of the vehicle body so as to define a housing space opening toward an outer side in the vehicle width direction and to cover a lower side of the support arm when the movable step is in a retracted position,

wherein the cover member includes a bottom wall that is disposed under the support arm and a peripheral wall that is erected at an edge of the bottom wall so as to extend upward toward the lower surface of the vehicle body, and

wherein the peripheral wall is provided with a seal member that is interposed between the peripheral wall and the lower surface of the vehicle body.

2. The step device according to claim 1 , wherein a sloping surface that slopes downward while extending from a vehicle front side toward a vehicle rear side is provided at a vehicle front-side part of the peripheral wall provided at a front end portion of the cover member.

3. The step device according to claim 1 , wherein the cover member is disposed at a higher level than a lower end of a rocker flange that is provided on the lower surface of the vehicle body.

4. The step device according to claim 1 , further comprising a sub-step that is disposed under the door opening in a state of being fixed to the vehicle body, wherein the cover member has the housing space together with the lower surface of the vehicle body and a lower surface of the sub-step.

5. A step device for a vehicle, the step device comprising:

a movable step supported under a door opening;

a coupling member that, in a state of being supported by a sliding door that moves in a vehicle front-rear direction with a shifting zone in a vehicle width direction, engages with the movable step to move the movable step in the vehicle width direction in conjunction with opening and closing of the sliding door,

a support arm that has a first pivot-joint point relative to a vehicle body and a second pivot-joint point relative to the movable step, and supports the movable step toward an upper side; and

a cover member that is fixed to a lower surface of the vehicle body so as to define a housing space opening toward an outer side in the vehicle width direction and to cover a lower side of the support arm when the movable step is in a retracted position, wherein

the cover member includes a bottom wall that is disposed under the support arm and a peripheral wall that is erected at an edge of the bottom wall so as to extend upward toward the lower surface of the vehicle body, and

a sloping surface that slopes downward while extending from a vehicle front side toward a vehicle rear side is provided at a vehicle front-side part of the peripheral wall provided at a front end portion of the cover member.

6. The step device according to claim 5 , wherein the cover member is disposed at a higher level than a lower end of a rocker flange that is provided on the lower surface of the vehicle body.

7. The step device according to claim 5 , further comprising a sub-step that is disposed under the door opening in a state of being fixed to the vehicle body, wherein the cover member has the housing space together with the lower surface of the vehicle body and a lower surface of the sub-step.