Sensor element and method of manufacturing sensor element
AssigneeNGK Insulators, Ltd.
InventorsYuki Kajita, Yuma Tanabe
Life of this patent
Estimating the term…
Abstract
A sensor element is equipped with a main body including a cavity for taking in a gas on a distal end side thereof, and a porous protective layer covering an outer peripheral surface of the main body at the distal end side thereof. The porous protective layer is equipped with a water droplet blocking structure covering at least a part of a distal end surface, the part overlapping the cavity in a longitudinal direction, and a thin portion covering the distal end surface around the water droplet blocking structure.
Claims11
A sensor element comprising:
- a main body including a cavity on a distal end side of the main body, the cavity being configured to take in a gas;
- and
- a porous protective layer covering an outer peripheral surface of the main body on the distal end side,
- wherein the porous protective layer comprises:
- a water droplet blocking structure covering at least a part of a distal end surface of the main body, the part overlapping with the cavity in a longitudinal direction perpendicular to the distal end surface;
- and
- a thin portion that is thinner than the water droplet blocking structure and covering the distal end surface around the water droplet blocking structure and having an outer surface that is parallel to the distal end surface, and
- wherein the thin portion shortens diffusion paths required for the gas to reach an opening of the cavity.
A method of manufacturing a sensor element provided with a main body including a cavity on a distal end side of the main body, the cavity configured to take in a gas, and a porous protective layer covering an outer peripheral surface of the main body on the distal end side, the method comprising:
- depositing the porous protective layer on a side surface of the main body by plasma spraying, as a first thermal spraying process;
- and
- depositing the porous protective layer on a distal end surface of the main body by the plasma spraying, as a second thermal spraying process,
- wherein the second thermal spraying process comprises arranging a thermal spraying gun so as to face the distal end surface and aligning a nozzle center, at which a deposition efficiency of the thermal spraying gun is highest, on an extension line of the cavity in a longitudinal direction perpendicular to the distal end surface, performing plasma thermal spraying, and thereby forming the porous protective layer including a convex portion covering at least a part of the distal end surface, the part overlapping the cavity in the longitudinal direction, and a thin portion that is thinner than the convex portion and covering the distal end surface around the convex portion and having an outer surface that is parallel to the distal end surface, and
- wherein the thin portion shortens diffusion paths required for the gas to reach an opening of the cavity.
A method of manufacturing a sensor element provided with a main body including a cavity on a distal end side of the main body, the cavity configured to take in a gas, and a porous protective layer covering an outer peripheral surface of the main body on the distal end side, the method comprising:
- depositing the porous protective layer on a side surface of the main body by cold spraying, as a first spraying process;
- and
- depositing the porous protective layer on the distal end surface of the main body by the cold spraying, as a second spraying process,
- wherein the second spraying process comprises arranging a spraying gun so as to face the distal end surface and aligning a nozzle center, at which a deposition efficiency of the spraying gun is highest, on an extension line of the cavity in a longitudinal direction perpendicular to the distal end surface, performing spraying, and thereby forming the porous protective layer including a convex portion covering at least a part of the distal end surface, the part overlapping the cavity in the longitudinal direction, and a thin portion that is thinner than the convex portion and covering the distal end surface around the convex portion and having an outer surface that is parallel to the distal end surface, and
- wherein the thin portion shortens diffusion paths required for the gas to reach an opening of the cavity.
A sensor element comprising:
- a main body including a cavity at an end portion of the main body, the cavity being configured to take in a gas;
- and
- a porous protective layer provided on the main body and covering at least the end portion of the main body,
- wherein the porous protective layer comprises:
- a water droplet blocking structure covering an area corresponding to the cavity;
- and
- a peripheral portion adjacent to the water droplet blocking structure and covering the end portion of the main body,
- wherein the peripheral portion includes a recessed portion formed at a position closer to a center of the main body than a peripheral edge of a distal end surface of the end portion of the main body, and
- wherein the porous protective layer is formed to have a thickness that is thinner at the recessed portion than at the peripheral edge of the distal end surface.
Dependencies are inferred from the claim text.