Load detection device for vehicle seat

• US 9,021,888 B2
• Filed: 10/31/2012
• Issued: 05/05/2015
• Est. Priority Date: 10/31/2011
• Status: Active Grant

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Takuma, Setsu, Ichihara, Kan, Nishide, Harutomi, Nakayama, Koichi, Washino, Koji
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): COTEY, PHILIP L
• Application Number:
  US13/665,079
• Publication Number:
  US 20130104666A1
• Time in Patent Office: 916 Days
• Field of Search: 738/55
• US Class Current: 73/855
• CPC Class Codes: G01G 19/4142 for controlling activation of safety devices, e.g. airbag systems electrical circuits for triggering safety arrangements in case of vehicle accidents B60R21/015
• CPC Class Codes: G01L 1/2206 Special supports with preselected places to mount the resistance strain gauges; Mounting of supports

Abstract

A load detection device for a vehicle seat includes a strain generating body including a first end hole, a second end hole and a strain gauge, a first fixing member including a first middle shaft portion and a first end shaft portion, a second fixing member including a second middle shaft portion and a second end shaft portion, a bracket member including first and second fixing portions connected to each other with a connecting portion, first and second fixing holes, the first end shaft portion is press-fitted into the first fixing hole, the second fixing hole is fitted onto the second end shaft portion in a manner that the second fixing hole includes a degree of freedom of a movement thereof in a lengthwise direction and a movement thereof in a direction intersecting with the lengthwise direction is restricted, and a connecting member.

Claims

1. A load detection device for a vehicle seat, comprising:

a strain generating body including a first end hole at a first end portion of the strain generating body and a second end hole at a second end portion of the strain generating body, and a strain gauge being attached on the strain generating body between the first end hole and the second end hole;

a first fixing member including a first middle shaft portion press-fitted into the first end hole and a first end shaft portion protruding from the first middle shaft portion, the first fixing member being configured to be connected to one of a seat-side fixing member fixing the vehicle seat and a floor-side fixing member fixing the seat-side fixing member to a floor of the vehicle;

a second fixing member including a second middle shaft portion press-fitted into the second end hole and a second end shaft portion protruding from the second middle shaft portion, the second fixing member being configured to be connected to the one of the seat-side fixing member and the floor-side fixing member;

a bracket member including a connecting portion and first and second fixing portions connected to each other with the connecting portion, the bracket member including a first fixing hole at one of the first and second fixing portions and a second fixing hole at the other one of the first and second fixing portions, the first fixing hole being formed in a manner that the first end shaft portion of the first fixing member is configured to be press-fitted into the first fixing hole, the second fixing hole being formed to be fitted onto the second end shaft portion of the second fixing member in a manner that the second fixing hole includes a degree of freedom of a movement of the second fixing hole relative to the second end shaft portion of the second fixing member in a lengthwise direction of the strain generating body and in a manner that a movement of the second fixing hole relative to the second end shaft portion in a direction intersecting with the lengthwise direction is restricted;

a connecting member integrally connected to a center portion of the strain generating body and connected to the other one of the seat-side fixing member and the floor-side fixing member; and

fastening nuts each of which is formed to include an outside dimension that is larger than a diameter dimension of the second fixing hole along a lengthwise direction thereof and which are used for fastening directly to the first and second fixing portions, respectively,

wherein the second fixing member is fitted to the second end shaft portion of the second fixing hole in a manner that the second fixing hole is restricted from moving relative to the second end shaft portion of the second fixing member in the direction which intersects, on a surface to which the strain gauge is attached, with the lengthwise direction of the strain generating body, and in a manner that the other one of the first and second fixing portions, at which the second fixing hole is formed, is restricted from moving relative to the second end shaft portion of the second fixing member in an insertion direction of the second fixing member,

wherein the second fixing hole is fitted onto the second end shaft portion of the second fixing member with a clearance therebetween, the clearance encircles the entire second end shaft portion, and the clearance hole reduces the movement of the second fixing hole relative to the second end shaft portion in the direction intersecting with the lengthwise direction of the strain generating body, and

wherein the fastening nut is formed so that an inner diameter of a screw hole of a bearing surface opening end of each of the fastening nuts is larger than a diameter dimension of the second fixing hole along a lengthwise direction.

2. The load detection device according to claim 1, wherein the second fixing hole is constituted by an elongated hole including a width-across-flat portion extending in the lengthwise direction of the strain generating body.

3. The load detection device according to claim 1,

wherein each of the fastening nuts includes a bearing surface which is formed so that an area of contact at which the bearing surface of the fastening nut fastening the other one of the first and second fixing portions, at which the second fixing hole is formed, is in contact with the bracket member is equal to an area of contact at which the bearing surface of the fastening nut fastening the one of the first and second fixing portions, at which the first fixing hole is formed, is in contact with the bracket member.

4. The load detection device according to claim 2,

wherein each of the fastening nuts includes a bearing surface which is formed so that an area of contact at which the bearing surface of the fastening nut fastening the other one of the first and second fixing portions, at which the second fixing hole is formed, is in contact with the bracket member is equal to an area of contact at which the bearing surface of the fastening nut fastening the one of the first and second fixing portions, at which the first fixing hole is formed, is in contact with the bracket member.

5. The load detection device according to claim 2, wherein the second fixing hole includes circular arc portions each connected to corresponding end portions of the width-across-flat portions.

6. The load detection device according to claim 1, wherein the clearance is larger in the lengthwise direction of the upper bracket than the clearance is in the direction that intersects the lengthwise direction.