Seat Structure

• US 20070236071A1
• Filed: 04/01/2005
• Published: 10/11/2007
• Est. Priority Date: 04/02/2004
• Status: Active Grant

• Current Assignee: Delta Tooling Co., Ltd. (Delta Kogyo Company Limited)
• Original Assignee: Delta Tooling Co., Ltd. (Delta Kogyo Company Limited)
• Inventors: Fujita, Etsunori, Ogura, Yumi, Ueno, Yoshiyuki
• Granted Patent: US 7,971,939 B2
• Time in Patent Office: Days
• US Class Current: 297/452.500
• CPC Class Codes: B60N 2/70 Upholstery springs ; Upholstery
• CPC Class Codes: B60N 2/7058 Metallic springs
• CPC Class Codes: B60N 2/7094 Upholstery springs

Abstract

A seat structure which can ameliorate fatigue of a sitting person in accordance with a long period of sitting is provided.

In a vehicle seat 10, a back edge side of a lower layer sheet 50 of a cushion material 20, of which a front edge side is fixed to a front edge side of a sitting portion frame 14, is resiliently connected to a back edge side of the sitting portion frame 14 via a movable frame 34 and a torsion bar 46, which is a resilient member. The cushion material 20 has a spring zero characteristic in which a spring constant of a portion that supports a protrusion portion of the sitting person is smaller than a spring constant of other portions. This vehicle seat 10 makes smaller the energy of vibrations which are transmitted to a spinal column portion of the sitting person through the sitting portion frame 14, and peripheral portions thereof convert vibrations corresponding to fluctuations in the body and transmit these through the sitting portion frame 14. α waves of 10 Hz to 12 Hz, which occur in a relaxed waking state, are caused in the brain of the sitting person. Vibrations in a resonance frequency region are attenuated in amplitude and transmitted to the sitting person.

Claims

1. A seat structure comprising:

a sitting portion frame; and

a cushion material including a sheet material, of which a front edge side is fixed at a front edge side of the sitting portion frame and a back edge side is connected to a back edge side of the sitting portion frame via a resilient member,

the cushion material including spring characteristics in which, in a stationary sitting state, a spring constant of a portion that supports a protrusion portion of a sitter is smaller than a spring constant of another portion.

2. The seat structure described in claim 1, wherein a vibration transmissibility when a vibration in a resonance frequency region of a spinal column of the sitter is input via the sitting portion frame is approximately 1, and a vibration transmissibility when a vibration in a frequency region which causes α

waves in a brain of the sitter is input via the seat frame is at most approximately 0.55.

3. The seat structure described in claim 1, wherein a resonance frequency of a system including the sitter, the cushion material and the resilient member is in a range of at least 3 Hz and at most 4 Hz.

5. The seat structure described in claim 1, wherein the resilient member deforms such that the back edge side of the sheet material moves forward or downward when a downward load acts on the cushion material.

7. The seat structure described in claim 5, further comprising, at the cushion material, another sheet material which is tensioned onto the sitting portion frame at an upper side of the sheet material and which presses a region of the sheet material corresponding to a buttock portion of a sitter such that the resilient member is deformed.

8. The seat structure described in claim 7, wherein the other sheet material is structured with a three-dimensional woven fabric or a two-dimensional woven fabric.

9. The seat structure described in claim 7, formed such that a jerk of a seat cushion which is structured to include the sitting portion frame and the cushion material is smaller than an intrinsic jerk of muscle of the buttock portion of a sitter.

10. The seat structure described in claim 5, further comprising a pivoting member, of which a lower end side is supported at a back edge side of the sitting portion frame so as to be pivotable about an axis along a left-right direction of the sitting portion frame, and an upper end side is anchored at the back edge side of the sheet material which is connected to the sitting portion frame via the resilient member,

the resilient member includes a torsion bar which is provided at the pivoting axis of the pivoting member, and which resiliently twistingly deforms in accordance with pivoting of the pivoting member.

11. The seat structure described in claim 5, further comprising other resilient members which are provided between a back edge side of the sitting portion frame and two respective left-right direction edge portions at the back edge side of the sheet material connected to the sitting portion frame via the resilient member, the other resilient members increasing a front-rear direction tension of the sheet material accompanying sitting.

12. The seat structure described in claim 5, further comprising a sheet-form member, which is provided forward of a position corresponding to a hipbone joint of the sitter in a sitting state, and which by tension which acts accompanying sitting restricts downward distorting of the sheet material connected to the sitting portion frame via the resilient member.

13. The seat structure described in claim 1, further comprising a seat back which includes:

a back portion frame which is a resilient structure;

a back portion cushion material;

first resilient members which respectively connect two left-right direction edge portions of an upper end side of the back portion cushion material to an upper end side of the back portion frame; and

second resilient members which respectively connect two left-right direction edge portions of a lower end side of the back portion cushion material to a lower end side of the back portion frame,

and the seat back being formed so as to support an upper body of a sitter by the resilient members.

15. The seat structure described in claim 13, further comprising a third resilient member, which is provided between the back portion cushion material and the back portion frame, and which causes left-right direction tension at a position of the back portion cushion material that corresponds with a lumbar portion of the sitter.

16. The seat structure described in claim 15, wherein the first resilient members, the second resilient members and the third resilient member are respectively tension coil springs.

4. A seat structure comprising:

a sitting portion frame; and

a cushion material including a sheet material, of which a front edge side is fixed at a front edge side of the sitting portion frame and a back edge side is connected to a back edge side of the sitting portion frame via a resilient member,

in which seat structure an attenuation ratio when a sitter displaces upward is set larger than an attenuation ratio when the sitter displaces downward.

6. A seat structure comprising:

a sitting portion frame;

a cushion material including a sheet material of which a front edge side is fixed at a front edge side of the sitting portion frame; and

a resilient member which is provided between a rear portion of the sitting portion frame and a back edge side of the sheet material, tensioning the sheet material onto the sitting portion frame, and deforming such that the back edge side of the sheet material descends while moving forward when a downward load acts on the sheet material.

14. A seat structure which comprises:

a back portion frame;

a back portion cushion material;

first resilient members which respectively connect two left-right direction edge portions of an upper end side of the back portion cushion material to an upper end side of the back portion frame; and

second resilient members which respectively connect two left-right direction edge portions of a lower end side of the back portion cushion material to a lower end side of the back portion frame,

and the seat structure being formed so as to support an upper body of a sitter by the resilient members.

17. A seat structure comprising:

a back portion frame; and

a back portion cushion material with at least one end side of an up-down direction of which connected to the back portion frame via a resilient member, which is tensioned onto the back portion frame, and which forms a flat backrest in a non-sitting state.