Bolt with function of measuring strain

• US 20070017295A1
• Filed: 07/19/2005
• Published: 01/25/2007
• Est. Priority Date: 07/19/2005
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ohta, Hiroyuki, Sumigawa, Takashi
• Granted Patent: US 7,293,466 B2
• Time in Patent Office: Days
• US Class Current: 73/761
• CPC Class Codes: F16B 31/02 for indicating the attainment of a particular tensile load or limiting tensile load apparatus for, or method of, determining value of torque or twisting moment for tightening a nut or other member similarly stressed G01L5/24
• CPC Class Codes: G01B 7/18 using change in resistance
• CPC Class Codes: G01L 5/0004 Force transducers adapted for mounting in a bore of the force receiving structure G01L5/0009 takes precedence
• CPC Class Codes: G01L 5/24 for determining value of torque or twisting moment for tightening a nut or other member which is similarly stressed

Abstract

A bolt with a function of measuring strain, comprising a Wheatstone bridge circuit comprising a strain sensor and a dummy resistor, a translate circuit that amplifies a signal from the Wheatstone bridge circuit to convert the same into a digital signal, a transmitting circuit that transmits the digital signal outside the bolt, and a power circuit, by which electromagnetic wave energy received from outside the bolt is supplied as a power source for at least any one of the circuits.

Claims

1. A bolt with a function of measuring strain, the bolt being provided with a Wheatstone bridge circuit comprising a strain sensor and a dummy resistor, a translate circuit that amplifies a signal from the Wheatstone bridge circuit to convert the same into a digital signal, a transmitting circuit that transmits the digital signal outside the bolt, and a power circuit, by which electromagnetic wave energy received from outside the bolt is supplied as a power source for at least any one of the circuits.

2. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed on a common silicone monocrystal member, the strain sensor includes an n-type impurity diffusion layer, the dummy resistor includes a p-type impurity diffusion layer, the strain sensor is formed to be lengthwise in a <

100>

direction of the silicone, and the dummy resistor is formed to be lengthwise in a <

110>

direction of the silicone.

3. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed on a common silicone monocrystal substrate, the strain sensor includes a first region formed by diffusing a p-type impurity layer in the silicone substrate, the first region is formed to be lengthwise in a <

110>

direction of the silicone substrate, the dummy resistor includes a second region formed by diffusing a p-type impurity layer in the silicone substrate, and the second region is formed to be lengthwise in a <

100>

direction of the silicone substrate.

4. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal substrate, the strain sensor includes a first region formed by diffusing an n-type impurity layer in the silicone substrate, the first region is formed to be lengthwise in a <

100>

direction of the silicone substrate, the dummy resistor includes a second region formed by diffusing an n-type impurity layer in the silicone substrate, and the second region is formed to be lengthwise in a <

110>

direction of silicone.

5. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal member comprising, the strain sensor includes a p-type impurity diffusion layer, the dummy resistor includes an n-type impurity diffusion layer, and the strain sensor and the dummy resistor are formed to be lengthwise in a <

110>

direction of the silicone monocrystal member.

6. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal member, the strain sensor includes a p-type impurity diffusion layer, the dummy resistor includes an n-type impurity diffusion layer, and the strain sensor and the dummy resistor are formed to be lengthwise in a <

100>

direction of the silicone monocrystal member.

7. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal member, the strain sensor includes a p-type impurity diffusion layer, the dummy resistor includes an n-type impurity diffusion layer, the strain sensor is formed to be lengthwise in a <

100>

direction of the silicone monocrystal member, and the dummy resistor is formed to be lengthwise in a <

110>

direction of the silicone monocrystal member.

8. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal member, the strain sensor includes a first region formed by diffusing a p-type impurity layer in the silicone substrate, the first region is formed to be lengthwise in a <

110>

direction of the silicone monocrystal member, the dummy resistor includes a second region formed by diffusing a p-type impurity layer in the silicone substrate, and the second region is formed to be lengthwise in a <

100>

direction of the silicone monocrystal member.

9. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal member, the strain sensor includes a first region formed by diffusing an n-type impurity layer in the silicone substrate, the first region is formed to be lengthwise in a <

100>

direction of the silicone monocrystal member, the dummy resistor includes a second region formed by diffusing an n-type impurity layer in the silicone substrate, and the second region is formed to be lengthwise in a <

110>

direction of the silicone monocrystal member.

10. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal member, the strain sensor includes a first region formed by diffusing a p-type impurity layer in the silicone substrate, the dummy resistor includes a second region formed by diffusing an n-type impurity layer in the silicone substrate, and the first region and the second region are formed to be lengthwise in a <

110>

direction of the silicone monocrystal member.

11. A bolt according to claim 1, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal member, the strain sensor includes an n-type impurity diffusion layer, the dummy resistor includes a p-type impurity diffusion layer, and the n-type impurity diffusion layer and the p-type impurity diffusion layer are formed to be lengthwise in a <

100>

direction of the silicone monocrystal member.

12. A bolt with a function of measuring strain, wherein a Wheatstone bridge circuit comprising a strain sensor and a dummy resistor, a translate circuit that amplifies a signal from the Wheatstone bridge circuit to convert the same into a digital signal, a transmitting circuit that transmits the digital signal outside the bolt, and a power circuit, by which electromagnetic wave energy received from outside the bolt is supplied as a power source for at least any one of the circuits are provided in a hole formed in the bolt, and wherein the translate circuit, the transmitting circuit, and the power circuit are formed on a common semiconductor chip, and a power supply ground of the semiconductor chip and the bolt are electrically connected.

13. A bolt with a function of measuring strain, wherein a Wheatstone bridge circuit comprising a strain sensor and a dummy resistor, a translate circuit that amplifies a signal from the Wheatstone bridge circuit to convert the same into a digital signal, a transmitting circuit that transmits the digital signal outside the bolt, and a power circuit, by which electromagnetic wave energy received from outside the bolt becomes a power source for any one of the circuits are mounted in a hole formed in a direction along a lengthwise axis of the bolt, and wherein the Wheatstone bridge circuit and the power circuit are formed on a common monocrystal semiconductor chip.

14. A bolt with a function of measuring strain, wherein a Wheatstone bridge circuit comprising a strain sensor and a dummy resistor, a translate circuit that amplifies a signal from the Wheatstone bridge circuit to convert the same into a digital signal, a transmitting circuit that transmits the digital signal outside the bolt, a power circuit, by which electromagnetic wave energy received from outside the bolt becomes a power source for at least any one of the circuits, and a temperature sensor are mounted on the bolt, and the temperature sensor and the Wheatstone bridge circuit are formed in a common silicone monocrystal member, and the temperature sensor comprises an impurity diffusion layer of the member.

15. A bolt with a function of measuring strain, wherein a Wheatstone bridge circuit comprising a strain sensor and a dummy resistor is mounted in a hole formed in a direction along a lengthwise axis of the bolt, and the Wheatstone bridge circuit is formed in a single monocrystal semiconductor chip.

16. A bolt according to claim 15, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, include regions formed by diffusing an impurity in the silicone substrate, the strain sensor includes a first region formed so that a lengthwise direction of a p-type impurity diffusion region is substantially in agreement with a <

110>

direction of the silicone monocrystal member, and the dummy resistor includes a second region formed so that a lengthwise direction of a p-type impurity diffusion region is substantially in agreement with a <

−

110>

direction of the silicone monocrystal member, and a lengthwise direction of the first region is substantially in agreement with the direction along the lengthwise axis of the bolt, and a lengthwise direction of the second region is substantially perpendicular to the direction along the lengthwise axis of the bolt.

17. A bolt according to claim 15, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, include regions formed by diffusing an impurity in the silicone substrate, the strain sensor includes a first region formed so that a lengthwise direction of an n-type impurity diffusion region is substantially in agreement with a <

110>

direction of the silicone monocrystal member, and the dummy resistor includes a second region formed so that a lengthwise direction of an n-type impurity diffusion region is substantially in agreement with a <

−

110>

direction of the silicone monocrystal member, and a lengthwise direction of the first region is substantially in agreement with the direction along the lengthwise axis of the bolt, and a lengthwise direction of the second region is substantially perpendicular to the direction along the lengthwise axis of the bolt.

18. A bolt according to claim 15, wherein the strain sensor and the dummy resistor, which constitute the Wheatstone bridge circuit, are formed in a common silicone monocrystal substrate, the strain sensor includes a first region formed by diffusing a p-type impurity layer in the silicone substrate, the first region is formed to be lengthwise in a <

110>

direction of the silicone substrate, the dummy resistor includes a second region formed by diffusing a p-type impurity layer in the silicone substrate, and the second region is formed to be lengthwise in a <

100>

direction of the silicone substrate.