JP5044296B2 - Temperature sensor element and temperature sensor - Google Patents

Description

  The present invention relates to a temperature sensor, and more particularly to a temperature sensor that detects the temperature of an engine or exhaust gas.

  In the field of automobile engines, various sensors are known, such as a temperature sensor that measures the in-cylinder temperature and exhaust gas temperature of an internal combustion engine, and a flow rate sensor that measures an intake air flow rate. For example, Patent Document 1 discloses extending the life of a temperature sensor while accurately detecting the in-cylinder temperature by using a plurality of SiC (silicon carbide) fibers in the temperature sensor.

  Patent Document 2 discloses a temperature sensor that is excellent in heat resistance, thermal responsiveness, and the like by sandwiching a heat-sensitive film between electric insulating films formed on a metal support (substrate). Furthermore, Patent Document 3 discloses that a temperature sensor is formed on an electrical insulating film formed on a silicon substrate and covered with a protective layer such as silicon dioxide to provide a highly accurate flow sensor. .

Here, a temperature measurement method using a two-wire thermocouple will be described as an example of a temperature measurement method in the above-described temperature sensor. In the temperature measurement method using a two-wire thermocouple, two thermocouples having different heat capacities are used. For example, in Non-Patent Document 1, the time constants of two thermocouples are calculated from the simultaneous equations (3), respectively, and the difference between the calculated time constants is canceled by the calculation, so that the rapidly changing temperature is accurately measured. Is disclosed.
Japanese Utility Model Publication No. 5-199130 WO96 / 35932 publication JP 2004-257870 A Masato Tagawa and two others, “Temperature Measurement of Turbulent Combustion Field Using Two-Wire Thermocouple”, Transactions of the Japan Society of Mechanical Engineers (Part B) Vol. 62, No. 598 (1996-6), p. 414-420

  By the way, in the method of measuring temperature using the two thermocouples described above, it is known that the temperature followability of the temperature sensor is improved by reducing the wire diameter of the thermocouple. There was a limit to reducing the wire diameter of the thermocouple from the viewpoint of mechanical strength.

  This invention is made | formed in view of such a situation, and it aims at providing the temperature sensor element and temperature sensor which suppress degradation of mechanical strength, maintaining the temperature followability with respect to a temperature change. .

A temperature sensor element of the present invention for solving such a problem includes a substrate including a thick portion having a predetermined thickness and a thin portion having a thickness smaller than the thick portion, an electrical insulating film formed on the substrate, possess a first thermocouple film formed on the electrical insulating film on the thick portion, and a second thermocouple film portion on the electrical insulating film on the thin-walled portion is formed, a, The first thermocouple film and the second thermocouple film are different in thickness .
According to this configuration, since the thickness of the substrate where the first thermocouple is formed is different from the thickness of the substrate where the second thermocouple is formed, the first thermocouple and the second thermocouple are different. Therefore, it is possible to provide a temperature sensor element using a temperature measuring method using a two-wire thermocouple. Further, according to this configuration, the heat capacities can be made different by making the thickness of the first thermocouple different from the thickness of the second thermocouple.

In addition, the temperature sensor element of the present invention includes a substrate including a thick portion having a predetermined thickness and a thin portion having a thickness smaller than the thick portion, an electrical insulating film formed on the substrate, and an electric power on the thin portion. A first thermocouple film partially formed on the insulating film and a second thermocouple film partially formed on the thin insulating portion and having a thickness different from that of the first thermocouple film. A thermocouple film.
According to this configuration, even if the thickness of the portion of the substrate where the first thermocouple is formed is the same as the thickness of the portion of the substrate where the second thermocouple is formed, the first thermocouple It is also possible to make the heat capacities different by making the thickness and the thickness of the second thermocouple different.

Further, the temperature sensor of the present invention has a temperature sensing part including the temperature sensor element described above, a sensor attachment part including a sheath pin core connected to one end of the temperature sensor element, and a lead wire attached to the other end of the sheath pin core. It has a lead wire attachment portion.
According to this configuration, it is possible to provide a temperature sensor including a temperature sensor element that uses a temperature measurement technique using a two-wire thermocouple.

  ADVANTAGE OF THE INVENTION According to this invention, it can be set as the temperature sensor element and temperature sensor which suppressed deterioration of mechanical strength, maintaining the temperature followability with respect to a high-speed temperature change.

(First embodiment)
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, the best mode for carrying out the invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an overall configuration of a temperature sensor 100 according to an embodiment of the present invention.

  As shown in FIG. 1, the temperature sensor 100 uses a temperature sensor element 102 having two thermocouples. For example, the temperature sensor 100 is attached to an exhaust pipe of an automobile and is used for temperature detection of exhaust gas.

  First, the temperature sensing part A that incorporates the temperature sensor element 102 and detects the temperature of exhaust gas or the like will be described. The temperature sensing part A is composed of a metal tube 101, a temperature sensor element 102, a cement 103, and the like. The tip side 101a of the metal tube 101 is curled and then closed by welding, and the temperature sensor element 102 is housed inside the tip side 101a. The periphery of the temperature sensor element 102 is filled with cement 103, thereby preventing the temperature sensor element 102 from swinging due to vibration during use.

  Next, the sensor attachment part B to which the temperature sensor element 102 is attached will be described. The sensor mounting portion B is composed of a protective tube 104, a nut 105, a sheath pin 108, and the like. The rear end side 101b of the metal tube 101 is open, the rear end side 101b is inserted into the protective tube 104, the rear end surface is brought into contact with a receiving port provided on the inner peripheral surface of the protective tube 104, and argon welding is performed. Has been fixed.

  A nut 105 having a hexagonal nut portion 105a and a screw portion 105b is rotatably fitted to the outer peripheral surface of the protective tube 104. In the temperature sensor 100, the front end surface of the protective tube 104 is brought into contact with an attachment portion provided at a predetermined position of the exhaust pipe, and is fixed by a nut 105. This prevents leakage of exhaust gas and the like from the temperature detection portion to the outside.

  A small-diameter portion is formed on the outer peripheral surface of the end portion on the rear end side 104b of the protective tube 104, and one end side of the joint 106 is fitted into the small-diameter portion and is argon-welded. The outer diameters of the joint 106 and the rear end side 104b of the protective tube 104 are substantially the same, and there are almost no steps in the connecting portion.

  Inside the metal tube 101, the protective tube 104, and the joint 106, a seaspin 108 that includes a pair of seaspin core wires 107 is disposed. The temperature sensor element 102 is connected via a Pt / Rh alloy wire 109. The Pt / Rh alloy wire 109 is formed by simultaneous firing with the temperature sensor element 102, and the Pt / Rh alloy wire 109 is resistance welded to the sheath pin core wire 107.

  Further, the lead wire attachment portion C for attaching the lead wire 111 to the sheath pin core 107 will be described. The lead wire mounting portion C includes a joint 106, a terminal electrode 110, a lead wire 111, a bush 112, and the like. One end of a pair of lead wires 111 is connected to the sheath pin core wire 107 drawn from the rear end side 108 b of the sheath pin 108 inside the joint 106 by a terminal electrode 110. The lead wire 111 is enclosed in a bush 112 made of heat-resistant rubber, and the other end is drawn out to the outside. The bush 112 and the joint 106 are fixed to each other when the joint 106 is rounded or hexagonally crimped from the outer peripheral surface side, and the bush 112 and the joint 106 are sufficiently adhered to each other and airtightness is maintained. Thereby, a sealed space is formed inside the metal tube 101, the protective tube 104, and the joint 106, and the temperature sensor element 102 is accommodated in the sealed space.

  Since this temperature sensor 100 is used in a high temperature environment as high as 1000 ° C., each component member needs to have sufficient heat resistance. Therefore, the metal tube 101, the sheath pin core 107, and the sheath pin 108 are formed of SUS310S, which is a heat-resistant alloy containing Fe as a main component and containing C, Si, Mn, P, S, Ni, and Cr. The protective tube 104 is made of SUS309S, which is a heat-resistant alloy having the same composition except that the amount ratio of Cr is slightly lower than that of SUS310S. Further, the joint 106 is formed of SUS304, which is a heat-resistant alloy having a similar composition except that the amount ratio of Cr is lower.

Next, the temperature sensor element 102 described above will be described in more detail with reference to FIGS.
2 is a partially enlarged view of the temperature sensor element 102, and FIG. 3 is a cross-sectional view of the temperature sensor element 102 taken along the line AA.

As shown in FIG. 2, the temperature sensor element 102 includes a first thermocouple 102b and a second thermocouple respectively formed in desired shapes on an electrically insulating thin film plate 102a made of SiO ₂ or the like. 102c. The thin film plate 102a is applied to the upper surface and / or the lower surface of the substrate 102d such as a single crystal silicon wafer so as to have a thickness of about 0.01 mm.

  Further, as shown in FIG. 3, a part of the substrate 102d is removed by silicon etching or the like to have a cavity 102e having a desired size. Thereby, the board | substrate 102a will be provided with the thin part 102y thinner than the thickness of the thick part 102x which has predetermined thickness, and the thick part 102x. Note that the cross-sectional shape of the hollow portion 102e is not limited to that shown in FIG. 3, and may be formed to be generally trapezoidal as shown in FIG. 4, for example. At this time, as shown in the figure, the thickness of the thin portion 102y may be eliminated. Even in such a form, the heat capacities are different.

  As shown in FIGS. 2 and 4, the first thermocouple 102b is formed so as to cross a part thereof on the thin film plate 102a on the thin portion 102y. By forming the first thermocouple 102a in such a manner, a portion where the first thermocouple 102a crosses becomes a thermally insulated thin film plate 102a because the substrate 102d does not exist under the thin film plate 102a.

  Further, as shown in FIG. 2, the first thermocouple 102b has a zigzag shape on the thin film plate 102a on the thin wall portion 102y, but a part of the shape is on the thin wall portion 102y. The shape is not limited to such a shape as long as it crosses over the thin film plate 102a, and may be, for example, a straight line, a curved line, an S-shape or an inverted S-shape. When the first thermocouple 102b has a zigzag shape on the thin film plate 102a on the thin wall portion 102y, the thermocouple becomes longer, and the accuracy as the temperature sensor is improved. Furthermore, the thickness of the first thermocouple 102b may be increased on the thin film plate 102a on the thick portion 102x. In FIG. 2, an area (hereinafter referred to as a thin-walled area) AR in a broken-line rectangle indicates that the thin-walled part 102y is below the thin-film plate 102a. The same applies to FIGS. 6, 8 and 9 described later.

  On the other hand, as shown in FIG. 2, the second thermocouple 102c is formed without crossing over the thin film plate 102a on the thin portion 102y. The shape of the second thermocouple 102c is not particularly limited, and may be a straight line, a curved line, an S-shape, an inverted S-shape, or the like, similar to the first thermocouple 102b. In addition, as shown in FIG. 5, the thickness of the second thermocouple 102c may be different from the thickness of the first thermocouple 102b, whereby the heat capacities of the two thermocouples are different.

  Therefore, two thermocouples having different heat capacities can be formed by changing the thicknesses of the portions of the substrate 102d where these thermocouples are formed, and a temperature measurement method using a two-wire thermocouple can be used. Therefore, it is possible to measure the temperature changing at high speed with good followability.

The first thermocouple 102a and the second thermocouple 102b are formed in a film shape on the thin film plate 102a by, for example, metal sputtering, metal paste printing, vapor deposition method, plating technique, CVD (vapor phase growth) method or the like. The
The materials of the first thermocouple 102b and the second thermocouple 102c are not particularly limited as long as they become thermocouples by heat treatment. Examples of these thermocouples include chromel (Ni-Cr alloy) -alumel (Ni-Al alloy), iron-constant (Ni-Cu alloy), platinum / rhodium-platinum, chromel-constant, and the like.

(Second Embodiment)
Subsequently, a temperature sensor element according to a second embodiment of the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the structure similar to each part of the temperature sensor element shown by FIG.2 and FIG.3, and the description is abbreviate | omitted.

  As shown in FIGS. 6 and 7, the temperature sensor element 102 according to the second embodiment is formed so that the second thermocouple 102 c crosses the thin film plate 102 a on the thin portion 102 y (not shown). As shown, the thickness is different from the thickness of the first thermocouple 102b.

  In this way, even if the first thermocouple 102b and the second thermocouple 102c are formed across the thin film plate 102a on the thin portion 102y, the heat capacities are different by making the thicknesses different from each other. A temperature measurement technique using a two-wire thermocouple can be used. Therefore, it is possible to measure the temperature changing at high speed with good followability.

  If the first thermocouple 102b and the second thermocouple 102c are formed across the thin film plate 102a on the thin portion 102y and have different thicknesses, the first thermocouple The shapes of the 102b and the second thermocouple 102c on the thin film plate 102a on the thin portion 102y are not particularly limited. For example, as shown in FIG. 8, the shape of the zigzag shape in the longitudinal direction is changed, or the shape of the first thermocouple is slid so as not to overlap as shown in FIG. You may make it a pair shape or make a zigzag-shaped part oppose.

  Note that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, a thermistor may be used without using a thermocouple for the temperature sensor element. Further, the present embodiment is not limited to this embodiment as long as two thermocouples are formed so as to have different heat capacities.

  As described above, according to the present invention, the thickness of the substrate where one thermocouple is formed and the substrate where the other thermocouple is formed are made different without reducing the wire diameter. Therefore, the heat capacity becomes different. Therefore, deterioration in mechanical strength can be suppressed while maintaining temperature followability with respect to a high-speed temperature change, and industrial applicability is high.

It is a schematic sectional drawing which shows the whole structure of a temperature sensor. It is the elements on larger scale of the temperature sensor element which concerns on 1st Embodiment. It is AA sectional drawing of a temperature sensor element. It is other AA sectional drawing of a temperature sensor element. It is other AA sectional drawing of a temperature sensor element. It is the elements on larger scale of the temperature sensor element which concerns on 2nd Embodiment. It is BB sectional drawing of a temperature sensor element. It is the other partial enlarged view of the temperature sensor element which concerns on 2nd Embodiment. It is the other partial enlarged view of the temperature sensor element which concerns on 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Temperature sensor 101 Metal tube 101a The front end side of a metal tube 101b The rear end side of a metal tube 102 Temperature sensor element 102a Thin film plate 102b 1st thermocouple 102c 2nd thermocouple 102d Substrate 102e Cavity part 102x Thick part 102y Thin part 103 Cement 104 Protective tube 104b Protective tube rear end side 105 Nut 105a Hex nut part 105b Screw part 106 Joint 107 Seaspin core wire 108 Seaspin 108b Seaspin rear end side 109 Pt / Rh alloy wire 110 Terminal electrode 111 Lead wire 112 Bush A feeling Warm part B Sensor mounting part C Lead wire mounting part AR Thin part area

Claims (3)

A substrate including a thick portion having a predetermined thickness and a thin portion having a thickness smaller than the thick portion;
An electrical insulating film formed on the substrate;
A first thermocouple film formed on the electrical insulating film on the thick part;
A second thermocouple film partially formed on the electrical insulating film on the thin-walled portion;
I have a,
The temperature sensor element, wherein the first thermocouple film and the second thermocouple film have different thicknesses . A substrate including a thick portion having a predetermined thickness and a thin portion having a thickness smaller than the thick portion;
An electrical insulating film formed on the substrate;
A first thermocouple film partially formed on the electrical insulating film on the thin-walled portion;
A second thermocouple film that is partially formed on the electrical insulating film on the thin-walled portion and has a thickness different from that of the first thermocouple film;
A temperature sensor element comprising: A temperature sensing part including the temperature sensor element according to claim 1;
A sensor mounting portion including a sheath pin core wire, one end of which is connected to the temperature sensor element;
A lead wire attaching portion to which a lead wire is attached to the other end of the sheath pin core;
A temperature sensor comprising:

Images