JPS6396525A - Temperature detecting element - Google Patents

Abstract

PURPOSE:To improve the mu characteristic of a low temperature side by forming a series circuit of a magnetic permeability of a thermosensible magnetic material and a resistance value of the thermosensible magnetic material itself, and correcting an impedance drop of the low temperature side. CONSTITUTION:Electrodes 31, 32 are provided on the upper and the lower faces of a thermosensible magnetic material 11, and a resistance value of the thermosensible magnetic material itself is fetched through this electrode. A coil 43 is wound round to the magnetic material 11, its terminal part 51 is connected to the electrode 31, and between the other end of this coil 43 and the electrode 32, an AC power source is impressed by an oscillating circuit OSC. According to such a constitution, an inductance by the coil 43 and a resistance of the thermosensible magnetic material 11 are connected in series, therefore, a temperature characteristic of its composite impedance drops suddenly in the vicinity of a Curie temperature, and as it falls from the Curie temperature, the impedance increases monotonously. As a result, a malfunction in a low temperature area, which has become a problem up to the present is prevented, and the working temperature range can be enlarged.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to temperature detection of heaters such as air conditioners and space heaters;
Alternatively, the present invention relates to a temperature detection element used for detecting the temperature of cooling water in automobiles, etc.

<Prior Art> FIG. 7 shows an example of a conventional temperature detection element, and FIG. 9 shows a block diagram of a temperature detection circuit using the temperature detection element shown in FIG. 7. The temperature-sensitive magnetic material 1 is made of Mn--Zn ferrite material, has a cylindrical shape, and has a conductive wire 2 coated with an insulating coating 21 wound N times.

The temperature characteristics of the magnetic permeability μ of the material itself of the temperature-sensitive magnetic material 1 are as follows.

As shown in FIG. 8(b), μ shows a maximum value immediately before the Curie temperature T0, and μ rapidly decreases at the Curie temperature Tc.

<Problems to be Solved by the Invention> Highly accurate temperature detection is possible by detecting the sudden drop in magnetic permeability μ just before the temperature Tc using a circuit.
In the .mu.-T characteristic, .mu. tends to decrease monotonically as the temperature decreases below the Curie temperature Tc, and as .mu. decreases at low temperatures, a problem arises in which malfunction occurs.

In the detection circuit of FIG. 9, an oscillation circuit O8C applies an alternating current of frequency f to the temperature sensor 10 shown in FIG. 7, and the output voltage V1 versus temperature T characteristic of the temperature sensor 10 is Since it is proportional to μ of the temperature-sensitive magnetic material, as shown in FIG. 8(a), the μ- of the constituent material of the temperature-sensitive magnetic body 1 is
The tendency is almost the same as that of the Ding characteristic. Here, the comparator value is selected to be VBF, and the temperature T1 is detected (T1
is one cucumber temperature T. It is 0.2-0.5℃ lower).

Due to the μmT% nature of the material itself, there is a temperature T' on the low temperature side that corresponds to IVBE, and T/ becomes the malfunction temperature.

Figure 10 shows the voltage-temperature characteristics of the detection circuit shown in Figure 9, and below the temperature T' on the low temperature side, the comparator C
It can be understood that a high level signal is output from the OP, resulting in malfunction.

In order to avoid malfunctions at temperature T', conventional product specifications have to be set at or above the operating environment temperature range e T /. Therefore, there has been a problem in that it is difficult to use it for applications that require a wide usage environment temperature range (for example, for automobiles, etc.).

On the other hand, other conventional countermeasures include adding a temperature compensation element such as a thermistor element in series with the temperature detection element to suppress the drop in output voltage in low temperature ranges, but the thermistor element The added cost of the amplifier and the integration of the temperature-sensitive magnetic material and thermistor element into a part of the sensor increased its size, resulting in performance problems such as a decrease in thermal response.

The purpose of the present invention is to correct the decrease in magnetic permeability μ in a low temperature range of a temperature sensing element using a conventional temperature-sensitive magnetic material. Another objective is to improve the μ characteristics on the low temperature side with a configuration that reduces the number of parts.

Means to Solve the Problem> First and second electrode portions are provided on opposite surfaces of a temperature-sensitive magnetic material having a predetermined shape, and the temperature-sensitive magnetic material is connected to a coil for applying a magnetic field. The terminal end of the coil wound around the temperature-sensitive magnetic material is electrically connected to the first electrode, and the starting end serves as one power terminal, and the second electrode has a terminal end electrically connected to the first electrode. , a temperature sensing element characterized in that a lead wire is connected to the other power terminal.

With the above configuration, the resistance value of the temperature-sensitive magnetic material itself can be obtained, and on the other hand, by flowing an alternating current between the two power supply terminals, the magnetic permeability μ of the temperature-sensitive magnetic material and its own resistance can be determined. By forming a series connection circuit with the value R, impedance drop on the low temperature side is improved.

<Embodiments of the Invention> Fig. 3 shows an external view of the temperature-sensitive magnetic material part used in the temperature detection element according to the present invention, and Fig. 1 shows temperature detection according to the present invention using the temperature-sensitive magnetic material shown in Fig. 3. An example of the element is shown. The temperature-sensitive magnetic body 11 has a cylindrical or annular shape, and furthermore,
Electrodes 31, 32 are provided on the lower side, respectively. The electrodes 31 and 32 are generally formed by heat treatment after applying a silver paste material, and have ohmic contact with the temperature-sensitive magnetic material 11.
Its own resistance value R is calculated. The temperature-sensitive magnetic material 11 is Mn
- Although it is a Zn-based ferrite material, its resistance characteristics are semiconductor-like, and its resistance value R vs. temperature T characteristic is the fourth
Figure (b) shows the throat, which shows a tendency to decrease monotonically as the temperature rises. in general.

The resistance value at room temperature is several Ω, and the rate of change in resistance value is 0.4% per 1°C, which is about the same as that of a normal thermistor.

FIG. 4(a) shows the magnetic permeability μ vs. temperature T characteristic, and the electrode 31
．． The addition of 32 has almost no effect on the conventional μ
- It is almost the same as T- property.

The embodiment shown in FIG. 1 has an insulating coating 4 on the temperature-sensitive magnetic body 11 shown in FIG.
01 is wound to form a coil 43, and its terminal end is electrically connected to the electric wire 31 by an electrical connection portion 51.

On the other hand, a conductive wire 42 is extended from the electrode 32 through the joint portion 52 . The joint portions 51, 52 are typically formed by soldering or the like. There is no series connection between the external terminals 411 and 422 with the inductance L component due to the coil portion 43 and the resistance value of the temperature-sensitive magnetic body 11 itself, and the temperature characteristics of the combined impedance are as shown by the broken line in FIG. 2(a). , the impedance tends to decrease rapidly near the Curie temperature T0, and increase monotonically as it decreases from Tc.

If the detection circuit shown in FIG. 9 is used, the temperature characteristic of the terminal voltage v2 of the temperature detection element will be approximately the same as the impedance trend shown in FIG. 2(,), and will therefore be as shown in FIG. 2(b).

In this way, the temperature T', which conventionally caused malfunctions, is
The terminal voltage vT' corresponding to is maintained at a value several times higher than the threshold voltage vBE of the converter. Therefore, malfunctions in low temperature ranges, which have been a problem in the past, are eliminated, and a wide operating temperature range can be guaranteed.

In addition, the size of the temperature sensing element itself depends only on the temperature-sensitive magnetic body 11, and compared to the conventional case where an external thermistor element is added, the size is clearly smaller and the number of parts is smaller than that of the thermistor. Since the temperature-sensitive magnetic body itself serves the function, the number of parts per unit is reduced compared to the conventional method, and it is also more advantageous in terms of cost than the conventional method.

6(a) and 6(b) show the shapes of temperature-sensitive magnetic bodies used in other embodiments of the present invention, and FIG. 5 shows a temperature-sensing element according to the present invention using the temperature-sensitive magnetic body of FIG. This is an example.

The temperature-sensitive magnetic body 12 is a circular thin plate, and electrode portions 33 and 34 are provided approximately at the center of its upper and lower surfaces. Fifth
As shown in the figure, a spiral planar coil 6 on which an insulated wave M611 is applied is closely fixed to a surface on which an electrode 33 is provided.

The end portion is electrically connected to the electrode 33 by peeling off the insulating coating. On the other hand, a lead wire 61 is connected to the electrode 34. The end portions of the lead wires 61 and 62 can be regarded as a series circuit of the inductance L component due to the planar coil 6 and the resistance value R of the temperature-sensitive magnetic body 1 between the electrodes 33 and 34. Therefore, a terminal voltage vs. temperature characteristic similar to that shown in FIG. 2(b) can be obtained,
Malfunctions at low temperatures are prevented.

In the embodiment shown in FIG. 5, the temperature-sensitive magnetic body 12 is made thin, so that a temperature detection function with excellent thermal responsiveness is ensured.

<Effects of the Invention> As described above, according to the present invention, it is possible to provide a temperature detection element that compensates for the decrease in magnetic permeability μ in a conventional low temperature range without adding any additional parts, and it is possible to provide a temperature detection element that can be used over a wider temperature range than before. Accordingly, it is possible to provide a highly reliable temperature detecting element that can be kept at a low cost and can also be miniaturized.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the temperature detection element according to the present invention, and FIGS. 2(a) and 2(b) show the induction 2-temperature T characteristic and output voltage v2 in the embodiment of FIG. An explanatory diagram of T-characteristics at one temperature, Figures 3(a) and (b) are perspective views and side views of the temperature-sensitive magnetic material used in the embodiment of Figure 1, and Figure 4(a)
, (b) is the magnetic permeability μ- of the temperature-sensitive magnetic material in Figure 3.
FIG. 5 is a perspective view of another embodiment of the temperature detection element according to the present invention; FIG.
Figures (a) and (b) are a perspective view and a side view of the temperature-sensitive magnetic material in Figure 5, Figure 7 is a perspective view of an example of a conventional temperature detection element, and Figures 8 (a) and (b). In Fig. 7, the output voltage v1 - temperature characteristic and the magnetic permeability μ - temperature characteristic Fig. 9 shows an example of a temperature detection circuit using a temperature sensor.
The figure shows an example of the operation of a detection circuit using a conventional temperature detection element. 1.11, 12 Two temperature-sensitive magnetic materials, 2, 4, 41: Conductor, 6
: Planar coil, 31, 33: First electrode. 32.34: Second electrode. 1st rIA ■・ Third factor of TCL hot water temperature (a) (b) Figure 4 Figure 5 Figure 6 (a) (b) Figure 7 Figure 9 Temperature (°C)

Claims (3)

[Claims] 1. First and second electrode portions are provided on opposite surfaces of a temperature-sensitive magnetic body having a predetermined shape, a coil for applying a magnetic field is provided to the temperature-sensitive magnetic body, and the coil is connected to the temperature-sensitive magnetic body. The terminal end of the winding wound around the magnetic material is electrically connected to the first electrode, the starting end is used as one power terminal, and a lead wire is connected to the second electrode to connect the other terminal. A temperature detection element characterized by having a power supply terminal. 2. In the temperature sensing element according to claim 1, the temperature-sensitive magnetic body has an annular or rectangular shape forming a closed magnetic path, a winding is wound around the temperature-sensitive magnetic body, and the first and second 2. A temperature detection element characterized in that electromagnetic waves No. 2 are applied to the upper and lower surfaces of the temperature-sensitive magnetic body. 3. In the temperature sensing element according to claim 1, the temperature-sensitive magnetic body is in the form of a thin plate, and the first and second electrodes are provided on the lower surface thereof, and the first and second electrodes are provided on the lower surface thereof, and the temperature-sensitive magnetic body is in the form of a thin plate. , a spiral planar coil is arranged, the terminal end of the planar coil is electrically connected to a first electrode on the corresponding temperature-sensitive magnetic material plane, and the starting end is set as one power terminal, A temperature detection element characterized in that a lead wire is connected to the second electrode to serve as the other power supply terminal.