Seat device of vehicle

1. A seat device of a vehicle, comprising:

a seat comprising a seat cushion and a seatback which is connected to a rear end portion of the seat cushion; and

a slide rail provided to attach the seat to a floor panel such that a position of the seat is longitudinally adjustable within a specified longitudinal range,

wherein said slide rail as a specified front-upward slant angle within a range of 9-11 degrees relative to the floor panel such that said seat slides longitudinally with said specified front-upward slant angle and is adjustable over said specified longitudinal range along the slide rail, a thigh support portion is provided at a front end portion of said seat cushion so as to swing vertically around a rear portion thereof with an adjustable swing-angle range of 4 degrees or greater, and said seat device of the vehicle does not comprise any other lift mechanism for adjusting a height of said seat other than said slide rail.

2. The seat device of the vehicle of claim 1 , further comprising an assist spring for operational-force reduction which reduces an operational force of adjusting the position of said seat along said slide rail having the specified front-upward slant angle.

3. The seat device of the vehicle of claim 1 , wherein the front-upward slant angle of said slide rail is set substantially at 10 degrees.

4. The seat device of the vehicle of claim 1 , wherein the adjustable swing-angle range of said thigh support portion is set substantially at 5 degrees.

5. The seat device of the vehicle of claim 1 , wherein the specified longitudinal range of the seat's adjustable position and the front-upward slant angle of said slide rail are set such that a first shortest clear-vision distance between eye points of a driver and a ground intersection point of a line of sight of an AF05 seated in the seat located at a forward position of the side rail is within a preset specified distance range and a second shortest clear-vision distance between eye points of the driver and the ground intersection point to the line of sight of a AM95 seated in the seat located at a rear end position of the slide rail is within said preset specified distance range.

6. The seat device of the vehicle of claim 5 , wherein said specified distance range of the first and second shortest clear-vision distance is set at 7.0-8.1 m.

7. The seat device of the vehicle of claim 5 , wherein a difference between a largest distance and a smallest distance of said preset specified distance range of the first and second shortest clear-vision distances is set at 1.5 m or less.

8. The seat device of the vehicle of claim 1 , wherein a steering wheel of the vehicle is not provided with a telescopic mechanism.

9. A seat device of a vehicle, comprising:

a seat comprising a seat cushion and a seatback which is connected to a rear end portion of the seat cushion; and

a slide rail provided to attach the seat to a floor panel such that a position of the seat is longitudinally adjustable within a specified longitudinal range,

wherein said slide rail has a specified front-upward slant angle within a range of 9-11 degrees relative to the floor panel such that said seat slides longitudinally with said specified front-upward slant angle and is adjustable over said specified longitudinal range along the slide rail.

10. The seat device of the vehicle of claim 9 , further comprising an assist spring for operational-force reduction which reduces an operational force of adjusting the position of said seat along said slide rail having the specified front-upward slant angle.

11. The seat device of the vehicle of claim 9 , wherein the front-upward slant angle of said slide rail is set substantially at 10 degrees.

12. A seat device of a vehicle, comprising:

a seat comprising a seat cushion and a seatback which is connected to a rear end portion of the seat cushion; and

a slide rail provided to attach the seat to a floor panel such that a position of the seat is longitudinally adjustable within a specified longitudinal range and said slide rail has a specified front-upward slant angle relative to the floor panel such that said seat slides longitudinally with said specified front-upward slant angle and is adjustable over said specified longitudinal range along the slide rail;

wherein the specified longitudinal range of the seat's adjustable position and the front-upward slant angle of said slide rail are set such that a first shortest clear-vision distance between eye points of a driver and a ground intersection point of a line of sight of an AF05 seated in the seat located at a forward position of the side rail is within a preset specified distance range and a second shortest clear-vision distance between eye points of the driver and the ground intersection point to the line of sight of an AM95 seated in the seat located at a rear end position of the slide rail is within said preset specified distance range; and

said seat device of the vehicle does not comprise any other lift mechanism for adjusting a height of said seat other than said slide rail.

13. The seat device of the vehicle of claim 12 , further comprising an assist spring for operational-force reduction which reduces an operational force of adjusting the position of said seat along said slide rail having the specified front-upward slant angle.

14. The seat device of the vehicle of claim 12 , wherein the front-upward slant angle of said slide rail is set within a range of 9-11 degrees relative to the floor panel.

15. The seat device of the vehicle of claim 14 , wherein the front-upward slant angle of said slide rail is set substantially at 10 degrees.