Distortion detector

• US 7,658,118 B2
• Filed: 09/30/2005
• Issued: 02/09/2010
• Est. Priority Date: 10/05/2004
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Mori, Hiroaki, Matsukawa, Yasunori, Yosiuti, Sigehiro, Kawasaki, Shusaku, Kobayashi, Yasunobu
• Primary Examiner(s): Caputo; Lisa M
• Assistant Examiner(s): ROY, PUNAM P
• Application Number:
  US11/663,284
• Publication Number:
  US 20080245157A1
• Time in Patent Office: 1,593 Days
• Field of Search: 737/69, 738/620.44, 738/620.45
• US Class Current: 73/862.044
• CPC Class Codes: G01L 1/2231 the supports being disc- or ring-shaped, adapted for measuring a force along a single direction
• CPC Class Codes: G01L 5/101 using sensors inserted into the flexible member

Abstract

A strain detector includes a bridge circuit having at least two strain resistance elements, a substrate, a first fixed member, and a second fixed member. The substrate has a circuit portion electrically connected to the strain resistance elements. The strain resistance elements are arranged on the substrate. The first fixed member is fixed to a center of an area, where an outer periphery of the area is set at a position at which the strain resistance elements are arranged. The second fixed member is fixed outside the position, where the strain resistance elements are arranged at the substrate. A center of an axis of the first fixed member, a center of an axis of the second fixed member, and the center of the area are positioned on a straight line, and the first fixed member and the second fixed member are arranged on two mutually opposed surfaces of the substrate.

Claims

1. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at a center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements,

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis,

wherein at least one of the first fixed member and the second fixed member is fixed to the substrate by one of welding and adhesion,

wherein the second fixed member is fixed to the substrate by one of welding and adhesion, and

wherein a periphery of the substrate in a region where the second fixed member is fixed is flush with a periphery of the second fixed member such that the periphery of the substrate and the periphery of the second fixed member form a flat edge for welding or adhesion.

2. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at the center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements,

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis, and

wherein at least one of the first fixed member and the second fixed member is fixed to the substrate by one of welding and adhesion, and has a coefficient of thermal expansion substantially equal to a coefficient of thermal expansion of the substrate.

3. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at a center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements,

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis, and

wherein the substrate is provided with a hole at the center of the mounting area, the first fixed member has a threaded portion disposed in the hole, and the first fixed member is clamped and fixed to the substrate at the threaded portion.

4. The strain detector according to claim 3, further comprising a fastening member which engages with the threaded portion.

5. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at the center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements, and

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis,

wherein the second fixed member includes a ring-shaped convex portion fixed to the substrate, a notch portion is provided on the convex portion in a position facing the circuit portion, and wherein the strain resistance elements are disposed on the second surface of the substrate.

6. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at a center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements,

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis, and

wherein the second fixed member includes a guide portion into which the substrate is inserted, the guide portion extending from the second surface of the substrate to the first surface of the substrate.

7. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at the center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements,

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis, and

wherein the substrate includes at least one insertion hole, and the second fixed member includes at least one hook portion extending through the insertion hole such that the second fixed member is suspended from the substrate.

8. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at a center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements,

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis,

wherein the substrate includes an outer periphery disposed between the first surface of the substrate and the second surface of the substrate, and

wherein the second fixed member includes a guide portion into which the substrate is inserted, the guide portion extending from the second surface of the substrate around the outer periphery and contacting the first surface of the substrate such that the second fixed member is held to the substrate.

9. A strain detector comprising:

a substrate having a mounting area;

a first fixed member fixed to the mounting area of the substrate on a first surface of the substrate, the first fixed member having a first longitudinal axis located at a center of the mounting area;

a second fixed member fixed to a second surface of the substrate, the second surface of the substrate being opposed to the first surface, the second fixed member having a second longitudinal axis coaxial with the first longitudinal axis;

a bridge circuit provided on the substrate and including at least two strain resistance elements, the strain resistance elements being disposed outside of the mounting area in a radial direction relative to the first longitudinal axis; and

a circuit portion provided on the substrate, the circuit portion being electrically connected to the strain resistance elements,

wherein the second fixed member is fixed to the second surface of the substrate at a region disposed outside of the strain resistance elements in a radial direction relative to the first longitudinal axis,

wherein the substrate includes a plurality of insertion holes, and

wherein the second fixed member includes a plurality of hook portions, each hook portion of the plurality of hook portions extending through an insertion hole of the plurality of insertion holes such that the second fixed member is suspended from the substrate.