Temperature sensing resistance element and thermal flow sensor using same

• US 20020189342A1
• Filed: 05/28/2002
• Published: 12/19/2002
• Est. Priority Date: 06/04/2001
• Status: Active Grant

• Current Assignee: NGK Insulators Limited
• Original Assignee: NGK Insulators Limited
• Inventors: Ishikawa, Zenji, Ishiguro, Fujio
• Granted Patent: US 6,647,779 B2
• Time in Patent Office: Days
• US Class Current: 73/204.26
• CPC Class Codes: G01F 1/69 of resistive type
• CPC Class Codes: G01K 7/18 the element being a linear resistance, e.g. platinum resistance thermometer G01K7/26 takes precedence
• CPC Class Codes: H01C 1/148 the terminals embracing or surrounding the resistive element H01C1/142 takes precedence

Abstract

The temperature sensing resistance element comprises a substrate made of an insulating material, a temperature sensing resistor formed on at least a part of the outer peripheral surface of the substrate so as to connect both ends of the substrate, a cap-shaped conducting member being electrically connected to the temperature sensing resistor and disposed at each end of the substrate, and a protective film covering at least the temperature sensing resistor. There is provided with a gap which is defined by an inner surface of the enlarged portion and a part of the outer surface of the substrate, and is widened gradually toward the end of the opening of the conducting member.

Claims

1. A temperature sensing resistance element, comprising

a substrate formed of an insulating material,

a temperature sensing resistor formed on at least a part of the outer peripheral surface of this substrate so as to connect both ends of this substrate,

a cap-shaped conducting member having an enlarged portion formed at a vicinity of an opening thereof and being electrically connected to the temperature sensing resistor and disposed at each end of this substrate, and a protective film for covering at least the above-described temperature sensing resistor,

wherein there is provided a gap defined by an inner surface of the enlarged portion and a part of the outer surface of the substrate, and being widened gradually toward an end of the opening of the conducting member.

2. The temperature sensing resistance element according to claim 1, wherein a level-difference portion formed at the boundary between the opening of the conducting member and the outer surface of the substrate is covered smoothly with this protective film 6 comprising a continuous curved line.

3. The temperature sensing resistance element according to claim 1, wherein a lead wire made of a noble metal alloy or a lead wire whose base metal core wire is covered with a noble metal is fixed at each outer surface of said cap-shaped conducting member.

4. The temperature sensing resistance element according to claim 2, wherein a lead wire made of a noble metal alloy or a lead wire whose base metal core wire is covered with a noble metal is fixed at each outer surface of said cap-shaped conducting member.

5. A thermal flow sensor, comprising a temperature sensing resistance element, comprising a substrate formed of an insulating material, a temperature sensing resistor formed on at least a part of the outer peripheral surface of this substrate so as to connect both ends of this substrate, a cap-shaped conducting member having an enlarged portion formed at a vicinity of an opening thereof and being electrically connected to the temperature sensing resistor and disposed at each end of this substrate, a protective film for covering at least the above-described temperature sensing resistor, and a gap defined by an inner surface of the enlarged portion and a part of the outer surface of the substrate and being widened gradually toward an end of the opening of the conducting member,

wherein said temperature sensing resistance element is built into a bridge circuit.

6. A temperature sensing resistance element, comprising:

a cylindrical substrate formed of an insulating material,

a temperature sensing resistor formed on an outer peripheral surface of the substrate for connecting both ends of the substrate,

a conducting member formed in a cap-like shape being electrically connected to a temperature sensing resistor and disposed at each end of the substrate, and

a protective film for covering at least the above-described temperature sensing resistor,

wherein the radius of curvature of both end edges of said substrate is 0.05 mm or more.

7. The temperature sensing resistance element according to claim 6, wherein a level-difference portion formed at the boundary between the opening of the conducting member and the outer surface of the substrate is covered smoothly with this protective film 6 comprising a continuous curved line.

8. The temperature sensing resistance element according to claim 6, wherein a lead wire made of a noble metal alloy or a lead wire whose base metal core wire is covered with a noble metal is fixed at each outer surface of said cap-shaped conducting member.

9. The temperature sensing resistance element according to claim 7, wherein a lead wire made of a noble metal alloy or a lead wire whose base metal core wire is covered with a noble metal is fixed at each outer surface of said cap-shaped conducting member.

10. A thermal flow sensor, comprising a temperature sensing resistance element, comprising a cylindrical substrate formed of an insulating material, a temperature sensing resistor formed on an outer peripheral surface of the substrate for connecting both ends of the substrate, a cap-shaped conducting member being electrically connected to a temperature sensing resistor and disposed at each end of the substrate, and a protective film for covering at least the above-described temperature sensing resistor;

both end edges of said substrate having a radius of curvature of 0.05 mm or more,

wherein said temperature sensing resistance element is built into a bridge circuit.