# US 10,309,839 B2 · Temperature sensor > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,309,839 B2 - Document ID: US10309839B2 - Status: Granted - Kind: B2 - Application number: 15/326,730 - Filed: 2015-07-01 - Published: 2017-07-20 - Granted: 2019-06-04 - Earliest claimed: 2014-07-17 - Assignees: Denso Corporation - Applicants: Denso Corporation - Inventors: Kouichi Yoshida; Shigeru Murata - Web page: https://patentgrep.com/patent/US10309839B2 ## CPC - G01K 7/02: using thermoelectric elements, e.g. thermocouples - G01K 1/08: Protective devices, e.g. casings - G01K 2205/04: for measuring exhaust gas temperature - G01K: MEASURING TEMPERATURE; MEASURING QUANTITY OF HEAT; THERMALLY-SENSITIVE ELEMENTS NOT OTHERWISE PROVIDED FOR (radiation pyrometry G01J5/00) ## Abstract A temperature sensor includes: a sheath tube; a pair of thermocouple wires inserted into the sheath tube; a temperature measuring junction of the pair of thermocouple wires; an insulating support disposed in the sheath tube; and a tip protective tube covering the outer periphery of a tip end of the sheath tube to surround the temperature measuring junction. The tip protective tube includes a base-end side tube portion and a tip-end side tube portion, the tip-end side tube portion having a diameter smaller than that of the base-end side tube portion. The tip-end side tube portion has a tip-end side portion filled with a first insulating filler in which the temperature measuring junction is buried. In the remaining part on the inside of the tip-end side tube portion, an air layer is formed. ## Claims ### Claim 1 A temperature sensor comprises: a sheath tube; a pair of thermocouple wires inserted into the sheath tube; a temperature measuring junction formed by joining tip ends of a tip projecting portion of the pair of thermocouple wires with each other, the tip projecting portion being projected from the sheath tube; an insulating support disposed in the sheath tube; and a tip protective tube that covers an outer periphery of a tip-end of the sheath tube to surround the temperature measuring junction, wherein, the tip protective tube includes a base-end side tube portion that covers the outer periphery of the tip end of the sheath tube, and a tip end-side tube portion formed at a position adjacent to a tip-end side of the base-end side tube portion, the tip-end side tube portion having a diameter smaller than a diameter of the base-end side tube portion, a tip end of the tip-end side tube portion being closed; the tip-end side tube portion has a tip-end side portion filled with a first insulating filler, the first insulating filler burying the temperature measuring junction therein; and the tip-end side tube portion has a portion adjacent to a base-end side of the first filler, the portion being formed with an air layer. ### Claim 2 (depends on 1) The temperature sensor according to claim 1, wherein, the tip-end side tube portion includes a middle step portion connected to the base-end side tube portion, and a tip portion formed at a position adjacent to a tip-end side of the middle step portion, the tip portion having a diameter smaller than a diameter of the middle step portion, the tip portion having a closed tip end; and the temperature measuring junction is disposed inside the tip portion. ### Claim 3 (depends on 2) The temperature sensor according to claim 2, wherein, a base-end surface of the first filler is located inside the middle step portion. ### Claim 4 (depends on 1) The temperature sensor according to claim 1, wherein, a distance from the tip end of the sheath tube to a center of the temperature measuring junction is in a range of 5 to 15 mm; a distance from the tip end of the sheath tube to the base-end surface of the first filler is in a range of 1 to 5 mm; and a distance from the base end surface of the first filler to the center of the temperature measuring junction is in a range of 1 to 10 mm. ### Claim 5 (depends on 2) The temperature sensor according to claim 2, wherein, a distance from the tip end of the sheath tube to a center of the temperature measuring junction is in a range of 5 to 15 mm; a distance from the tip end of the sheath tube to the base-end surface of the first filler is in a range of 1 to 5 mm; and a distance from the base end surface of the first filler to the center of the temperature measuring junction is in a range of 1 to 10 mm. ### Claim 6 (depends on 3) The temperature sensor according to claim 3, wherein, a distance from the tip end of the sheath tube to a center of the temperature measuring junction is in a range of 5 to 15 mm; a distance from the tip end of the sheath tube to the base-end surface of the first filler is in a range of 1 to 5 mm; and a distance from the base end surface of the first filler to the center of the temperature measuring junction is in a range of 1 to 10 mm. ### Claim 7 (depends on 2) The temperature sensor according to claim 2, wherein, the tip-end side tube portion has an inner surface coated with an insulating material; and a distance from a tip end of the temperature measuring junction to an inner tip end of the tip portion of the tip-end side tube portion is 0.1 mm or less. ### Claim 8 (depends on 3) The temperature sensor according to claim 3, wherein, the tip-end side tube portion has an inner surface coated with an insulating material; and a distance from a tip end of the temperature measuring junction to an inner tip end of the tip portion of the tip-end side tube portion is 0.1 mm or less. ### Claim 9 (depends on 1) The temperature sensor according to claim 1, wherein, the first filler and the second filler are configured by particle aggregates made of ceramics, and a glass layer made of crystallized glass filling gaps between the particle aggregates. ### Claim 10 (depends on 1) The temperature sensor according to claim 1, wherein: a length of the air layer, extending from the tip end of the sheath tube to a base-end surface of the first filler in an axial direction of the air layer, is in a range of 1 to 5 mm. ### Claim 11 (depends on 2) The temperature sensor according to claim 2, wherein: the air layer is arranged inside the middle step portion, the middle step portion having a diameter smaller than that of the base-end side tube portion. ### Claim 12 (depends on 11) The temperature sensor according to claim 11, wherein: the air layer is further arranged in an inclined step portion between the middle step portion and the base-end side tube portion.