초록 ▼

In order to improve seating comfort and vibration absorbency, a structure including a first torsion bar unit 70 disposed in the rear of a seat cushion, and a second torsion bar unit 80 disposed in the front of the seat cushion, and a base net 60 stretched between a rear supporting frame 74 of the fi

In order to improve seating comfort and vibration absorbency, a structure including a first torsion bar unit 70 disposed in the rear of a seat cushion, and a second torsion bar unit 80 disposed in the front of the seat cushion, and a base net 60 stretched between a rear supporting frame 74 of the first torsion bar unit 70 and a front supporting frame 84 of the second torsion bar unit 80, is provided. Owing to the elastic force of a front torsion bar 81 of the second torsion bar unit 80 positioned in the front of the seat, a sense of stroke at the time of seating is enhanced. Owing to the elastic force of a rear torsion bar 71 of the first torsion bar unit 70 positioned in the rear of the seat, similarly to the conventional structure, a load of a seated person can be sufficiently received and a stable seating comfort can be obtained. Since both the first torsion bar unit 70 and the second torsion bar unit 80 work together to dampen vibration inputted during driving, vibration absorbency is more enhanced than ever.

대표청구항 ▼

What is claimed is: 1. A base net supporting mechanism for a seat cushion supporting a base net disposed under a cushioning member for the seat cushion, wherein the seat cushion is disposed across a seat frame, comprising: a first torsion bar unit including a torsion bar, arms connecting to the tor

What is claimed is: 1. A base net supporting mechanism for a seat cushion supporting a base net disposed under a cushioning member for the seat cushion, wherein the seat cushion is disposed across a seat frame, comprising: a first torsion bar unit including a torsion bar, arms connecting to the torsion bar, and a supporting frame supported by the arms, and said arms being provided at a rear of the seat cushion and being pivotal forward and rearward around the torsion bar acting as a fulcrum, wherein said first torsion bar unit is provided so that the torsion bar acting as a fulcrum is positioned above the supporting frame supported via the arm; and a second torsion bar unit including a torsion bar, arms connecting to the torsion bar, and a supporting frame supported by the arms, and said arms being provided at a front of the seat cushion and being pivotal forward and rearward around said torsion bar acting as a fulcrum, wherein the base net is stretched between the supporting frame of said first torsion bar unit and said supporting frame of the second torsion bar unit. 2. The base net supporting mechanism for a seat cushion according to claim 1, wherein said second torsion bar unit is provided so that the torsion bar acting as a fulcrum is positioned lower than the supporting frame supported via the arm. 3. The base net supporting mechanism for a seat cushion according to claim 2, wherein an engaging bracket protruding downward is attached to the supporting frame of said second torsion bar unit, a front end of said base net is wound around the supporting frame and a portion to be engaged provided at the front end is engaged with said engaging bracket. 4. The base net supporting mechanism for a seat cushion according to claim 1, wherein an engaging bracket protruding upward is attached to the supporting frame of said first torsion bar unit, a rear end of said base net is wound around the supporting frame, and a portion to be engaged provided in the rear end is engaged with said engaging bracket. 5. The base net supporting mechanism for a seat cushion according to claim 1, wherein the pivoting range of the arm in said second torsion bar unit is set at an angle of 40�� around the torsion bar in both forward-tilting and rearward titling direction, respectively. 6. A seat structure having a cushioning member for a seat cushion wherein the seat cushion is disposed across a seat frame, and a base net disposed under the cushioning member for the seat cushion, comprising: a first torsion bar unit including a torsion bar, arms connecting to the torsion bar, and a supporting frame supported by the arms, and the arms being provided at a rear of the seat cushion being pivotal forward and rearward around the torsion bar acting as a fulcrum, wherein said first torsion bar unit is provided so that the torsion bar acting as a fulcrum is positioned above the supporting frame supported via the arm; and a second torsion bar unit including a torsion bar, arms connecting to the torsion bar, and a supporting frame supported by the arms, and said arms being provided at a front of the seat cushion and being pivotal forward and rearward around said torsion bar acting as a fulcrum, wherein the base net is stretched around the supporting frame of said first torsion bar unit and the supporting frame of said second torsion bar unit. 7. The seat structure according to claim 6, wherein said second torsion bar unit is provided so that the torsion bar acting as a fulcrum is positioned lower than the supporting frame supported via the arm. 8. The seat structure according to claim 7, wherein an engaging bracket protruding downward is attached to the supporting frame of said second torsion bar unit, a front end of said base net is wound around the supporting frame and a portion to be engaged provided in the front end is engaged with said engaging bracket. 9. The seat structure according to claim 6, wherein an engaging bracket protruding upward is attached to the supporting frame of said first torsion bar unit, a rear end of said base net is wound around the supporting frame and a portion to be engaged provided in the rear end is engaged with said engaging bracket. 10. The seat structure according to claim 6, wherein the pivoting range of the arm of said second torsion bar unit is set at an angle of 40�� around the torsion bar in both forward-tilting and rearward titling direction, respectively. 11. The seat structure according to claim 6, wherein side frames of the seat frame are elastically deformed when a load equal to or greater than a predetermined limit is placed rearward on a seat back during impact, the supporting frame of said first torsion bar unit relatively displaces in a lower forward-tilting direction, lowering tension of the base net, and increasing a damping ratio. 12. The seat structure according to claim 11, wherein a stopper member controlling a pivoting range of the arm of said second torsion bar unit in a rearward-tilting direction is provided, and when the arm of the second torsion bar unit abuts on the stopper member after the tension of said base net is loosened during impact, the stopper member deforms or displaces moving a control position of the arm further rearward, to further lower the tension of said base net. 13. The seat structure according to claim 6, further comprising: an auxiliary elastic mechanism provided under said base net between said first torsion bar unit and the second torsion bar unit, to support a load together with the base net. 14. The seat structure according to claim 13, wherein said auxiliary elastic mechanism comprises an auxiliary net disposed under the base net, and a coil spring elastically supporting the auxiliary net to the side frames of the seat frame. 15. The seat structure according to claim 13, wherein said auxiliary elastic mechanism is formed including an air cushion disposed under the base net and having a plurality of partitioned bulging portions.