JPS60244826A - Temperature sensor - Google Patents

Abstract

PURPOSE:To facilitate manufacture by flanging the end part of a sensor head to which a sensor chip for temperature detection and a sensor metallic fixture are fixed, and joining the flange fixedly to the flange at the end part of a cylindrical case. CONSTITUTION:The sensor chip 6 is fixed to a sensor head 15 with a joint layer 7. The sensor chip 6 consists of an insulating substrate 3, electrode film 4, and temperature sensing resistor film 5. Further, the sensor metallic fixture 9 is fixed to the sensor head 15. An insulating plate 8 is fitted to the sensor metallic fixture 9. A groove or hole 12 for guiding a sensor lead wire 11 is provided to the insulating plate 8. The sensor head 5 is provided with a flange, which is joined with the flange of a cylindrical case 16. The sensor head 15 is brought into contact with the bottom part of a cooking container 1 to detect the temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to the construction of a temperature sensor for a cooking device that is brought into contact with the bottom of a cooking container to detect the temperature of the food inside.

Structure of a conventional example and its problems FIG. 1 shows a conventional example. 1 is a cooking container, which is heated by a heating device (not shown). 2 is a sensor head that comes into contact with the bottom of the cooking container 1, and is integrally molded into a substantially cylindrical shape to prevent boiled liquid from entering. The dimensions are φ20 in diameter and 3 in length to accommodate and protect each part.
It is around 0 tomo.

Inside the sensor head 2, a sensor chip 6 formed of an electrode film 4 and a temperature-sensitive resistor film 5 using SiC is fixed on the surface of an insulating substrate 3 with a bonding layer 7 by brazing or adhesive, and further insulating A plate 8 is bent and a sensor fitting 9 fixed by caulking or the like is fixed by welding. Two terminals are attached to the insulating plate 8, and a groove or hole 12 for guiding the sensor lead wire 11 is provided. Both electrode films 4 of the sensor chip 6 are easily welded as sensor lead wires 11.
A thin platinum wire is generally used and welded in order to be highly durable and to reduce mechanical stress on the electrode film 4, and the sensor lead wire 11 is passed through the hole 12 of the insulating plate 8 and welded to the terminal 10. be done. Furthermore, an external lead wire 13 is welded to the terminal 10. Reference numeral 14 denotes an insulating film that covers the sensor chip 6 and a portion of the sensor lead wire 11.

In the above configuration, the size of the sensor heat sensitive part is small, and the sensor chip 7F is connected to the sensor metal fitting 9 and both lead wires 1.
Although precision is required in the assembly process such as welding and insulating film formation in 1.13, the sensor head 2 is integrally molded, so there are restrictions on the work method, poor workability, and the need for assembly jigs. It became complicated. Therefore, in the welding process, the sensor metal fitting 9 was insufficiently attached, and the platinum wire peeled off or broke, and if adhesive was used in the joining process, uniform adhesion could not be achieved and the sensor chip 6 was weakly fixed.

If the bonding layer 7 of the sensor chip 6 is soldered, silver solder foil,
It is not easy to stack the titanium foil, the silver solder foil (a bonding layer made of three types of laminated layers), and the sensor chip 6, and misalignment easily occurs, making it difficult to achieve good brazing. Problems such as the insulating film not being formed uniformly occurred, which made it difficult to maintain the quality of the sensor, making it unsuitable for mass production and expensive.

OBJECTS OF THE INVENTION It is an object of the present invention to solve these conventional problems and provide a temperature sensor that is highly reliable, easy to manufacture, and inexpensive.

Structure of the Invention In order to achieve this object, the present invention provides a sensor chip having a temperature-sensitive resistor film and a sensor metal fitting for holding a terminal fixed to an insulating plate for connecting both lead wires. A flange is provided at the end of the sensor head, and the flange is bonded and fixed to a flange provided at the end of a cylindrical case to form a heat sensitive section. This configuration improves the workability of sensor assembly and makes it possible to obtain a highly reliable and low-cost temperature sensor.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 2, 3, and 4. The same members as in FIG. 1 are given the same numbers.

Reference numeral 15 denotes a substantially disk-shaped sensor head that comes into contact with the bottom of the cooking container 1, and has a diameter of φ20, a thickness of about 2 gates, and a flange 15 provided at the end. The material is ferritic stainless steel, which has a coefficient of thermal expansion similar to that of the sensor chip 6. 16 is a cylindrical case, with a flange 16 at the end.
' is provided.

Both end portions 15' and 16' are joined and fixed to each other by projection welding to form a heat sensitive portion 17.

Inside the sensor head 15, a sensor chip 6 formed of an electrode film 4 and a temperature-sensitive resistor film 5 using SiC is bonded and fixed on the surface of an insulating substrate 3 with a bonding layer 7, and an insulating plate 8 is further fixed. The sensor fitting 9 is bent and fixed by caulking or the like, and then fixed by welding. A second terminal is attached to the insulating plate 8, and a groove or hole 12 for guiding the sensor lead wire 11 is provided. Thin platinum wire is generally used for both electrode films 4 of the sensor chip 6 as the sensor lead wire 11 because it is easy to weld, has high durability, and reduces mechanical stress on the electrode film 4. The sensor lead wire 11 is passed through the hole 12 of the insulating plate 8 and welded to the terminal 10. Furthermore, an external lead wire 13 is welded to the terminal 10. Reference numeral 14 denotes an insulating film that covers the sensor chip 6 and a portion of the sensor lead wire 11.

According to the above configuration, the assembly process involves assembling each component except for the case 16 into the approximately disk-shaped sensor head 15, and finally bringing the flange 16' of the case 16 and the flange 15' of the sensor head 15 into close contact and using projection welding. A heat sensitive section 17 can be formed.

Since the sensor head 15 is separated from the case 16 and has a substantially disk shape, there is a degree of freedom in the working method.
and the sensor chip 6, welding the sensor head 15 and the sensor metal fitting 9, welding the electrode film 4 of the sensor chip 6 and the sensor lead wire 11, welding the sensor lead wire 11 and the terminal 10,
The workability of each process such as coating the insulating film 14 is extremely good. Therefore, if the sensor chip 6 is bonded by adhesive, it will be evenly bonded, and if it is soldered, it will be bonded with silver solder foil.

Laminated layers of titanium foil and the like can be bonded reliably and without misalignment, resulting in a temperature sensor with good thermal response. Further, the sensor lead wire 11 and the sensor metal fitting 9 can be welded well, and reliable welding can be performed without disconnection or peeling.

Furthermore, if ferritic stainless steel is used for the sensor head 15, it will have high contact resistance and heat resistance, and can be manufactured at low cost.Since the coefficient of thermal expansion is similar to that of the sensor chip 6, there will be no damage due to thermal distortion, and it will have excellent thermal shock resistance. It becomes a temperature sensor. In particular, the bonding layer 7 between the sensor chip 6 and the sensor head 15
When joining two sheets of silver solder foil and titanium foil by brazing, it is necessary to use ferritic stainless steel to reduce thermal shock. Next, the insulating film 11 is also connected to the sensor chip 6.
It can be formed uniformly over the entire surface of the sensor chip 6, completely insulating the sensor chip 6, and also sufficiently reinforcing the welding of the sensor lead wire 11 to which the electrode film 4 is attached.

Next, another embodiment of the present invention is shown in FIG. The same members as in FIG. 2 are given the same numbers. 18 is a cylindrical case, and a flange 18' is provided at the end. The flange 18' is fixed to the flange 15' of the sensor head 15 by caulking to form a heat-sensitive section 19. The other configurations are the same as in FIG. 2.

Even with such a configuration, effects similar to those of the first embodiment can be obtained. Further, as shown in the embodiment, the sensor head 15 and the case 16 or 18 are joined by projection welding or caulking to provide a highly reliable temperature sensor that is easy to manufacture and to completely seal the entire circumference. Therefore, there is no problem with spilled liquid from the cooking container 1.

Effects of the Invention The present invention has a sensor chip in which an electrode film and a temperature-sensitive resistor film are formed on the surface of an insulating substrate, and a sensor metal fitting that holds a terminal fixed to an insulating plate for connecting both lead wires. The following effects can be obtained by providing a flange at the end of the substantially disk-shaped sensor head and joining and fixing the flange to a flange provided at the end of the cylindrical case.

(1) Since each part is assembled into a roughly disk-shaped sensor head, the joining and welding processes are easy, preventing peeling of each part or disconnection due to poor workmanship, and making it possible to obtain a highly reliable temperature sensor. can.

(2) Since the workability is good, mass production is possible using relatively simple equipment and jigs, and temperature sensors can be provided at low cost.

(3) By sealing and fixing the entire periphery of the sensor head and the flange of the case, the mechanical strength of the heat-sensitive part can be increased, and there is no fear that boiled liquid from the cooking container will infiltrate inside.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of the main parts of a conventional temperature sensor, FIG. 2 is a sectional view of the main parts of an embodiment of the temperature sensor of the present invention, and FIG. 3 is a sensor head and other parts of the temperature sensor of the present invention. FIG. 4 is a cross-sectional view of a case constituting the temperature sensor, and FIG. 5 is a cross-sectional view of main parts showing another embodiment of the temperature sensor of the present invention. 5... Temperature sensitive resistor film (temperature sensitive resistor), 6...
...Sensor chip, 8...Insulation plate, 9...
−・Sensor metal fittings, 10・・・Terminals, 11・Group・
Sensor lead wire, 13...External lead wire, 15
......sensor head, 15'...flange, 16...case, 16'...flange section, 17...heat sensitive section. Name of agent: Patent attorney Toshio Nakao (1st person)
Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) A sensor chip that has a temperature-sensitive resistor that detects temperature and a sensor metal fitting that holds a terminal that is fixed to an insulating plate that connects the sensor lead wire and the external lead wire. A temperature sensor in which a flange is provided at an end of a disc-shaped sensor head, and the flange is bonded and fixed to a flange provided at an end of a cylindrical case to form a temperature-sensing section. (2) The temperature sensor according to claim 1, wherein the sensor head is made of ferritic stainless steel. (3) The temperature sensor according to claim 1, in which the flange portion is fixed by projection welding or biting.