Gas sensor with increased heat resistance

A gas sensor comprising:

• a sensor element for detecting a concentration of specified gas in measuring gases;
• an element holder including a housing adapted to be mounted on a gas flow passage and an element-side insulator, fixedly retained in the housing, for fixedly supporting the sensor element;
• an atmosphere-side insulator placed on a base end portion of the element holder so as to cover a base end portion of the sensor element;
• an atmosphere-side cover, placed on the base end portion of the element holder and fixedly supported with the housing so as to cover the base end portion of the atmosphere-side insulator, which has a shoulder portion radially extending inward from an outer periphery of the atmosphere-side cover in face-to-face relation with a base end face of the atmosphere-side insulator;
• a pressing member interposed between the shoulder portion of the atmosphere-side cover and the base end face of the atmosphere-side insulator;
• and
• a heat-transfer restricting support member including a plurality of convexed ribs, formed on the shoulder portion of the atmosphere-side cover, which are held in abutting engagement with the pressing member in a minimum contact surface.

A gas sensor comprising:

• a sensor element for detecting a concentration of specified gas in measuring gases;
• an element holder including a housing adapted to be mounted on a gas flow passage and an element-side insulator, fixedly retained in the housing, for fixedly supporting the sensor element;
• an atmosphere-side insulator placed on a base end portion of the element holder so as to cover a base end portion of the sensor element;
• an atmosphere-side cover, placed on the base end portion of the element holder and fixedly supported with the housing so as to cover the base end portion of the atmosphere-side insulator, which has a shoulder portion radially extending inward from an outer periphery of the atmosphere-side cover in face-to-face relation with a base end face of the atmosphere-side insulator;
• a heat-transfer restricting support member acting as a pressing member and including an annular member having a plurality of spring portions, extending radially outward from an outer periphery of the annular member, which are interposed between the shoulder portion of the atmosphere-side cover and the base end face of the atmosphere-side insulator.

A gas sensor comprising:

• a sensor element for detecting a concentration of specified gas in measuring gases;
• an element holder including a housing adapted to be mounted on a gas flow passage and an element-side insulator, fixedly retained in the housing, for fixedly supporting the sensor element;
• an atmosphere-side insulator placed on a base end portion of the element holder so as to cover a base end portion of the sensor element;
• an atmosphere-side cover, placed on the base end portion of the element holder and fixedly supported with the housing so as to cover the base end portion of the atmosphere-side insulator, which has a shoulder portion radially extending inward from an outer periphery of the atmosphere-side cover in face-to-face relation with a base end face of the atmosphere-side insulator;
• a pressing member interposed between the shoulder portion of the atmosphere-side cover and the base end face of the atmosphere-side insulator;
• and
• a heat-transfer restricting support member including a plurality of convexed ribs, formed on the base end face of the atmosphere-side insulator, which are held in abutting engagement with the pressing member in a minimum contact surface.

A gas sensor comprising:

• a sensor element for detecting a concentration of specified gas in measuring gases;
• an element holder including a housing adapted to be mounted on a gas flow passage and an element-side insulator, fixedly retained in the housing, for fixedly supporting the sensor element;
• an atmosphere-side insulator, placed on a base end portion of the element holder so as to cover a base end portion of the sensor element, which has an upper protrusion and an annular base end face formed around the upper protrusion;
• an atmosphere-side cover, placed on the base end portion of the element holder and fixedly supported with the housing so as to cover the base end portion of the atmosphere-side insulator, which has an annular shoulder portion radially extending inward from an outer periphery of the atmosphere-side cover in face-to-face relation with the annular base end face of the atmosphere-side insulator;
• a pressing member interposed between the annular shoulder portion of the atmosphere-side cover and the annular base end face of the atmosphere-side insulator;
• and
• a heat-transfer restricting support member including a plurality of convexed ribs, formed on the annular shoulder portion of the atmosphere-side cover, which are held in abutting engagement with the pressing member in a minimum contact surface.

A gas sensor comprising:

• a sensor element for detecting a concentration of specified gas in measuring gases;
• an element holder including a housing adapted to be mounted on a gas flow passage and an element-side insulator, fixedly retained in the housing, for fixedly supporting the sensor element;
• an atmosphere-side insulator, placed on a base end portion of the element holder so as to cover a base end portion of the sensor element, which has an upper protrusion and an annular base end face formed around the upper protrusion;
• an atmosphere-side cover, placed on the base end portion of the element holder and fixedly supported with the housing so as to cover the base end portion of the atmosphere-side insulator, which has an annular shoulder portion radially extending inward from an outer periphery of the atmosphere-side cover in face-to-face relation with the annular base end face of the atmosphere-side insulator;
• a heat-transfer restricting support member acting as a pressing member and including an annular member having a plurality of spring portions, extending radially outward from an outer periphery of the annular member, which are interposed between the annular shoulder portion of the atmosphere-side cover and the annular base end face of the atmosphere-side insulator.

A gas sensor comprising:

• a sensor element for detecting a concentration of specified gas in measuring gases;
• an element holder including a housing adapted to be mounted on a gas flow passage and an element-side insulator, fixedly retained in the housing, for fixedly supporting the sensor element;
• an atmosphere-side insulator, placed on a base end portion of the element holder so as to cover a base end portion of the sensor element, which has an upper protrusion and an annular base end face formed around the upper protrusion;
• an atmosphere-side cover, placed on the base end portion of the element holder and fixedly supported with the housing so as to cover the base end portion of the atmosphere-side insulator, which has an annular shoulder portion radially extending inward from an outer periphery of the atmosphere-side cover in face-to-face relation with the annular base end face of the atmosphere-side insulator;
• a pressing member interposed between the annular shoulder portion of the atmosphere-side cover and the annular base end face of the atmosphere-side insulator;
• and
• a heat-transfer restricting support member including a plurality of convexed ribs, formed on the annular base end face of the atmosphere-side insulator, which are held in abutting engagement with the pressing member in a minimum contact surface.