Gas sensor
AssigneeNGK Insulators, Ltd.
InventorsShintaro Maki, Kota Katagiri, Kohei Yaita, Yuya Seike, Satoru Shiraishi
Life of this patent
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Abstract
Provided is a gas sensor that reduces a possibility that a terminal fitting electrically connecting a sensor element and a lead wire to each other breaks due to vibrations applied to the gas sensor. In the gas sensor according to one aspect of the present invention, a value obtained by dividing a second distance db, which is a distance from a start end that is an end of a reduced diameter portion of a tubular body on a frontmost end side to a positioning fixture of the terminal fitting, by a first distance Da, which is a distance from the start end to a protrusion of the tubular body, is 0.24 or more and 0.39 or less.
Claims6
A gas sensor capable of detecting a specific gas concentration of a gas to be measured, the gas sensor comprising:
- a sensor element that extends in an axial direction and includes a detection unit on a front end side and an element electrode on a rear end side;
- a terminal fitting that extends in the axial direction and includes an element contact portion electrically connected to the element electrode on the front end side;
- a ceramic housing that houses the element electrode and the element contact portion;
- a tubular body that has an open end and in which the sensor element, the terminal fitting, and the ceramic housing are disposed;
- a lead wire, the front side of which is crimped and fixed to a lead wire holder formed in the terminal fitting on the rear end side, and the rear end side of which extends outward from the open end;
- and
- an elastic body that is disposed so as to seal the open end and into which the lead wire is inserted,
- wherein the terminal fitting includes a positioning fixture that is locked to the ceramic housing to fix a position of the terminal fitting with respect to the ceramic housing,
- the tubular body includes, on the front end side, a protrusion that is in contact with an external member, to which the gas sensor is to be attached, and prevents leakage of the gas to be measured from a space defined by the external member,
- a reduced diameter portion that caulks a portion of the elastic body that accommodates the lead wire therein and extends in the axial direction from a periphery is formed in the tubular body on the rear end side, and
- a value obtained by dividing (2) a second distance Db that is a distance in the axial direction from a start end that is an end of the reduced diameter portion on a frontmost end side to the positioning fixture by (1) a first distance Da that is a distance in the axial direction from the start end to the protrusion is 0.24 or more and 0.39 or less.
Dependencies are inferred from the claim text.