JPH0534543U - Temperature sensor - Google Patents

Abstract

(57) [Summary] [Object] The present invention mainly relates to a temperature sensor for detecting an exhaust gas temperature used for controlling an internal combustion engine, and an object thereof is to provide a temperature sensor having excellent thermal responsiveness. To do. [Structure] A process for forming a heat receiving surface 5 on the sealing end side of a protective cylinder 1 made of a heat-resistant metal (for example, SUS-310S) in accordance with the shape of a heat sensitive element 2a made of an oxygen ion conductive solid electrolyte (for example, After crushing by a press), the heat-sensitive element 2a is housed, and alumina powder is filled as the amorphous heat-resistant material 6 in the gap between the heat-sensitive element 2a and the protective cylinder 1, and then the insulating support 7 of the heat-sensitive element 2a is formed. The protective cylinder 1 is bonded to the protective cylinder 1 with a heat-resistant inorganic adhesive 8, and the lead wire 9 for taking out the electric output of the heat sensitive element 2a is attached to the protective cylinder 1.
The temperature sensor 12 was constructed by connecting to the wiring cord 10 fitted on the open end side of.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention mainly relates to a temperature sensor for detecting an exhaust gas temperature used for controlling an internal combustion engine.

[0002]

[Prior Art]

 As a method for measuring the temperature of combustion exhaust gas in internal combustion engines and various combustion furnaces, a temperature sensor incorporating an oxygen ion conduction type or electron conduction type thermistor or a metal resistor as a heat sensitive element is used. As shown in FIG. 3 (a), the schematic structure of these temperature sensors has a thermosensitive element 2a composed of a thermistor or a metal resistor, and one end side which serves as a protective cover for the thermosensitive element and a mounting bracket for the sensor. It is housed in the sealed end side of the protective cylinder 1 made of a sealed heat-resistant metal, and the lead wire 9 for taking out its electric output is connected to the wiring cord 10 fitted to the open end side of the protective cylinder. It is like this.

[0003]

[Problems to be solved by the device]

 In the temperature sensor having the above-described structure, first, the exhaust gas temperature is received by the protective cylinder, and then the heat is transmitted from the protective cylinder to the heat-sensitive element. Generally, in a thermosensitive element consisting of a thermistor or a metal resistor, the thermosensitive response to heat transfer from a certain specific direction differs depending on the orientation of the thermosensitive element. It depends on the arrangement relationship with the metal terminals formed on. In order to obtain excellent thermal response, it is preferable to use a thermosensitive element that is thin in the direction perpendicular to the area sandwiched by a pair of metal terminals, and is located in this direction on the surface of the thermosensitive element. It is necessary to efficiently transfer heat to the specific surface (the most effective heat-sensitive surface) to be heated. However, the sealed end side of the protective cylinder used in the conventional temperature sensor has a cylindrical shape with a constant radius whose end is sealed in a substantially hemispherical shape regardless of the shape of the heat-sensitive element. As shown in FIG. 3 (b) showing the BB cross section in a), a large space existing between the most effective heat-sensitive surface of the heat-sensitive element and the protective cylinder is an obstacle to rapid heat transfer, There was a shortcoming that the heat-sensitive response speed was slow.

An object of the present invention is to solve such problems and to provide a temperature sensor having excellent thermal responsiveness.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a temperature sensor in which a thermosensitive element is housed in a protective cylinder, in which the inner side of the protective cylinder is placed in a direction parallel to the most effective thermal surface of the thermosensitive element. The first gist is a temperature sensor characterized in that the direction perpendicular to the most effective heat-sensitive surface is made small. . Further, in the present invention, the heat-sensitive element is provided in the protection cylinder such that the distance between the heat-sensitive element and the inner surface of the protection cylinder facing the heat-sensitive element is the shortest at at least one most effective heat-sensitive surface of the heat-sensitive element. A second aspect of the present invention is a temperature sensor according to claim 1, wherein the temperature sensor is housed in Further, a third aspect of the present invention is the temperature sensor according to claim 1 or 2, wherein an amorphous heat resistant material is filled in a gap formed between the heat sensitive element and the protective cylinder.

[0006]

【Example】

 The configuration of the present invention will be specifically described below based on the embodiments shown in the accompanying drawings. 1A and 1B are views showing an example of the structure of a temperature sensor constructed by using a disk-type thermosensitive element according to the present invention. FIG. 1A is a vertical sectional view and FIG. 1B is FIG. 1A. 3 is a sectional view taken along line AA in FIG. FIG. 2 is a perspective view showing a state in which the thermosensitive elements of various shapes are housed in the protective cylinder. The protective cylinder is partially omitted and only the sealing end side is shown.

A process for forming a heat receiving surface 5 on the sealing end side of the protective cylinder 1 made of a heat-resistant metal (for example, SUS-310S) so as to match the shape of the heat sensitive element 2a made of an oxygen ion conductive solid electrolyte. (For example, a crushing process by a press) is performed, and the inner side of the protective cylinder in the direction perpendicular to the most effective heat sensitive surface 3 or 3'of the heat sensitive element 2a is parallel to the most effective heat sensitive surface 3 or 3'of the heat sensitive element 2a. It is smaller than the inside of the protective cylinder. As shown in FIG. 2 (a), the thermosensitive element 2a is housed therein, and the gap between the thermosensitive element 2a and the protective cylinder 1 is filled with alumina powder as the amorphous heat-resistant material 6. The support 7 and the protective cylinder 1 were bonded together using a heat resistant inorganic adhesive 8. At this time, each position and direction were adjusted so that the distance between the heat-sensitive element 2a and the inner surface of the protective cylinder facing it was the shortest at the most effective heat-sensitive surface 3 or 3 '. Furthermore, the lead wire 9 for taking out the electric output of the thermosensitive element 2a was connected to the wiring cord 10 fitted to the open end side of the protective cylinder 1 to form the temperature sensor 12.

Also, as an example of a temperature sensor using a thermosensitive element of another shape according to the present invention, a perspective view of a state in which a film thermosensitive element 2b is housed in a protective cylinder is shown in FIG. 2 (b). Since these configurations are almost the same as those of the embodiment shown in FIG. 1, their details are omitted.

FIG. 4 is a graph showing the results of comparing the thermal response characteristics of the temperature sensor of the above-described embodiment with that of a conventional temperature sensor. The temperature sensor of the present invention has a response time shortened to about 3/4 compared to the conventional temperature sensor, and it was confirmed that the thermal sensitivity was significantly improved.

The heat-sensitive element used in the present invention may be of a well-known shape such as a bead type, a horseshoe type, or a column type, in addition to the above-mentioned embodiment. Further, the effect of accelerating the heat-sensitive response can be obtained without filling the gap between the heat-sensitive element and the protective cylinder with the amorphous heat-resistant material, but the filling of the amorphous heat-resistant material is more effective. preferable. As the amorphous heat-resistant material to be filled, ceramics such as spinel, magnesia, beryllia, silicon nitride, and silicon carbide, and heat-resistant and oxidation-resistant metals can be used in addition to the alumina listed in the examples. The shape may be powder, fiber, whisker, or the like. In order to obtain excellent heat-sensitive response, it is preferable to use a material having good thermal conductivity as much as possible. However, when filling up to the part that touches the metal terminals of the heat sensitive element, an insulating material is selected and used.

[0011]

[Effect of the device]

 As described above, the temperature sensor of the present invention has a structure in which the heat transfer path for the exhaust gas temperature maintains a uniform shortest distance to the most effective heat-sensitive surface of the heat-sensitive element, so that heat loss during heat transfer is reduced. The heat-sensitive response speed can be significantly reduced. Furthermore, by filling the gap between the heat-sensitive element and the protective tube with the amorphous heat-resistant material, the heat-sensitive response speed can be further increased. In addition, the filling of the amorphous heat resistant material also has an effect of preventing damage to the heat sensitive element due to vibration or shock.

[Brief description of drawings]

FIG. 1 is a vertical sectional view and a horizontal sectional view showing the structure of a temperature sensor of the present invention.

FIG. 2 is a perspective view showing a state in which various heat-sensitive elements are stored in a protective cylinder.

FIG. 3 is a longitudinal sectional view and a lateral sectional view showing the structure of a conventional temperature sensor.

FIG. 4 is a graph showing a thermosensitive response characteristic of the temperature sensor of the present invention.

[Explanation of symbols]

1 ························································ Disc type heat-sensitive element 2b ··· Membrane-type heat-sensitive element 3, 3 ′ ·· Most effective heat-sensitive surface 4 ··· 7 ... Insulating support 8 ... Heat-resistant inorganic adhesive 9 ... Lead wire for electrical output extraction 10 ... Wiring cord 11, 12 ...
Temperature sensor

Claims (3)

[Scope of utility model registration request] 1. A temperature sensor in which a heat sensitive element is housed in a protective cylinder, wherein the inner side of the protective cylinder is perpendicular to the most effective heat sensitive surface rather than the direction parallel to the most effective heat sensitive surface of the heat sensitive element. A temperature sensor characterized by having a smaller direction. 2. The thermosensitive element is provided in the protective cylinder such that the distance between the thermosensitive element and the inner surface of the protective cylinder facing the thermosensitive element is shortest at at least one most effective thermal surface of the thermosensitive element. The temperature sensor according to claim 1, wherein the temperature sensor is housed. 3. The amorphous heat resistant material is filled in a gap formed between the heat sensitive element and the protective cylinder.
Alternatively, the temperature sensor according to claim 2.