Temperature sensor having intermediate member connecting leads to element electrode wires extending from temperature detector
A temperature sensor includes a temperature detector having a thermosensitive element, element electrode wires, leads, and intermediate members. The temperature sensor is formed such that ends of the element electrode wires are embedded in the temperature detector, the leads are electrically connected to the respective element electrode wires, and the intermediate members electrically connect the element electrode wires to the respective leads. Each element electrode wire and the corresponding intermediate member are arranged being aligned in the extending direction, and bonded to each other, with opposing surfaces facing each other being abutted each other. The intermediate member and the corresponding lead are juxtaposed in a direction perpendicular to the extending direction, and bonded being overlapped with each other.
1. A temperature sensor comprising:
a temperature detector including a thermosensitive element for detecting a temperature;
a pair of element electrode wires made of a noble metal or a noble metal alloy, the pair of element electrode wires being formed so as to have respective ends embedded in the temperature detector and other respective ends extended in the same direction;
a pair of leads made of an Ni-based alloy or an Fe-based alloy, the pair of leads being formed so as to be electrically connected to the respective element electrode wires and extend in an extending direction of the respective element electrode wires; and
a pair of intermediate members made of an Ni-based alloy or an Fe-based alloy, the pair of intermediate members being formed so as to electrically connect the element electrode wires to respective leads and extend in the extending direction, wherein:
each of the element electrode wires and a corresponding one of the intermediate members are arranged being aligned in the extending direction, and bonded to each other in a state where mutually facing opposing surfaces are abutted with each other; and
each of the intermediate member and a corresponding one of the leads are juxtaposed in a direction perpendicular to the extending direction and bonded being overlapped with each other.
2. The temperature sensor according to claim 1 , wherein:
the temperature detector is accommodated in a cover member; and
the temperature detector and the cover member are secured by a filler filled in the cover member.
3. The temperature sensor according to claim 1 , wherein
in the extending direction, a length L 1 of a portion of each of the element electrode wires protruding from the temperature detector toward a corresponding one of the leads satisfies a relation 0.2 mm≤L 1 ≤8 mm.
4. The temperature sensor according to claim 1 , wherein
in the extending direction, an element side bonding portion bonding each of the element electrode wires to a corresponding one of the intermediate members is located at a position nearer the temperature detector than a tip end portion of a corresponding one of the leads is; and
a distance L 2 from the element side bonding portion to the tip end portion of the lead satisfies a relation 0 mm≤L 2 ≤8 mm.
5. The temperature sensor according to claim 1 , wherein
the pair of element electrode wires are formed of a Pt-based alloy doped with Rh or Ir.
6. The temperature sensor according to claim 5 , wherein
in a cross section perpendicular to the extending direction, an outer shape of each of the intermediate members is greater than an outer shape of a corresponding one of the element electrode wires; and
the outer shape of the intermediate member is large enough to cover the outer shape of the element electrode wire.
7. The temperature sensor according to claim 1 , wherein
a thermal expansion coefficient E 1 of the thermosensitive element is equal to a thermal expansion coefficient E 2 of the element electrode wire.
8. The temperature sensor according to claim 1 , wherein
a thermal expansion coefficient E 3 of the intermediate members is intermediate between the thermal expansion coefficient E 2 of the element electrode wires and a thermal expansion coefficient E 4 of the leads, and satisfies a relation E 2 ≤E 3 ≤E 4 .
9. The temperature sensor according to claim 1 , wherein
the intermediate members and the leads are formed of the same material.
10. The temperature sensor according to claim 1 , wherein
each of element electrode wires is bonded to a corresponding one of the intermediate members by welding, and each of the intermediate member is bonded to a corresponding one of the leads by welding.