Distortion Detector

• US 20080245157A1
• Filed: 09/30/2005
• Published: 10/09/2008
• Est. Priority Date: 10/05/2004
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Mori, Hiroaki, Kawasaki, Shusaku, Kobayashi, Yasunobu, Matsukawa, Yasunori, Yosiuti, Sigehiro
• Granted Patent: US 7,658,118 B2
• Time in Patent Office: Days
• US Class Current: 73/763
• 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 bridge circuit having at least two strain resistance elements;

a substrate having a circuit portion electrically connected to the strain resistance elements and arranging the strain resistance elements thereon;

a first fixed member fixed to a center of an area of the substrate, an outer periphery of the area being set at a position where the strain resistance elements are arranged; and

a second fixed member fixed outside the position, where the strain resistance elements are arranged, at the substrate,

wherein 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.

2. The strain detector according to claim 1,

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.

3. The strain detector according to claim 2,

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

a part of the substrate, to which the second fixed member is mounted, has an identical external shape with that of the second fixed member.

4. The strain detector according to claim 2,

wherein at least one of the first fixed member and the second fixed member, which is fixed to the substrate by one of welding and adhesion, substantially agrees with the substrate in coefficient of thermal expansion.

5. The strain detector according to claim 1,

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

6. The strain detector according to claim 5, further comprising a fastening member, which engages with the threaded portion.

7. The strain detector according to claim 1,

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

8. The strain detector according to claim 1,

wherein the second fixed member includes a guide portion, into which the substrate is inserted, on a side where the second fixed member is fixed to the substrate.

9. The strain detector according to claim 1,

wherein the second fixed member includes at least one hook portion on a side where the second fixed member is fixed to the substrate, and the substrate is provided with an insertion hole, into which the hook portion is inserted to suspend the second fixed member from the substrate.

10. The strain detector according to claim 1,

wherein the circuit portion corrects variation of the strain resistance elements in value of resistance.