JPS6028085B2 - temperature switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature switch configured using a reed switch.

Curie temperature, such as ferrite or Fe-Ni-Cr alloys (at this temperature, they rapidly lose their magnetism)
In recent years, temperature sensors such as temperature switches and thermal solid relays, which use reed switches to turn on and off, have been used to detect and control the temperature of high-temperature parts of household appliances, such as forced circulation oil heaters. It has been put into practical use.

As shown in Fig. 1, this type of temperature switch constructed using conventional temperature-sensitive magnetic materials includes a permanent magnet 1 such as a ferrite magnet, and a permanent magnet 1 such as a temperature-sensitive ferrite magnet that suddenly becomes magnetic at a certain temperature. The temperature-sensitive magnetic material 2 to be lost and the reed switch 4 are coupled by the magnetic material 3, and a loop of magnetic flux JT flows out from the magnet 1 and flows through the temperature-sensitive magnetic material 2 to create a magnetic closed circuit. There is one in which a reed switch 4 is provided in parallel with a loop of magnetic flux JR that creates a magnetic closed circuit passing through a bush piece.

According to this, when the temperature-sensitive magnetic material 2 is in a temperature range below the Curie temperature, most of the magnetic flux from the magnet 1 flows into the cape loop, and therefore the reed switch 4 is turned off (break state).
On the other hand, when the temperature rises to around the temperature of cue 1, the temperature-sensitive magnetic material 2 rapidly loses its magnetism, so most of the magnetic flux flows to the OR loop, and the reed switch 4 is turned on (make state), and then acts as a temperature switch that turns on and off as shown by curve A in Figure b in response to changes in temperature. By the way, when this type of temperature switch is incorporated into a forced circulation type kerosene heater, generally, as shown in Fig. 2, two parts of the temperature-sensitive magnetic material are directly attached to the high-temperature part A to be detected or controlled. A method is adopted in which the information is transmitted to the control unit B.

However, in order to downsize this type of temperature switch, the distance between the permanent magnet 1 or reed switch 4 and the temperature-sensitive magnetic material 2 is shortened, and the permanent magnet 1 and reed switch 4 move the yoke 3 away from the high temperature part A. There is a problem in that the temperature increases due to heat conducted through the wire.

That is, when the temperature becomes particularly high, the magnetic flux decreases due to the temperature characteristics of the permanent magnet 1, and the magnetic flux ■R passing through the reed switch 4 becomes
This results in the state shown by curve C in FIG. 2B, which causes instability in the on-operation as a temperature switch, and in extreme cases, there is a risk that the switch will not operate. This phenomenon is further aggravated by the temperature characteristics of the magnetic material forming the reed piece of the reed switch 4. In consideration of this problem, a permanent magnet 1 having sufficient magnetic flux is used. However, since forced circulation hot air heaters generally send cold outside air to the combustion section, the permanent magnet 1 and the reed switch 4 are cooled, and the above-mentioned instability factor is reduced.

However, when extremely low-temperature outside air is introduced and one part of the permanent magnet becomes cold, the magnetic flux of the permanent magnet 1 increases, and the magnetic flux ■R flowing to the reed switch 4 becomes as shown in the curve in Figure 1b. There is a risk that the heat sensitive part will remain in the on state even if it reaches the temperature at which it would normally turn off, causing the heat sensitive part to not operate as a switch. As described above, it is difficult to miniaturize the temperature switch shown in FIG. 1a when it is used in a device with extremely high and low temperatures, such as a forced circulation oil heater.

The present invention aims to solve these problems and provide a highly reliable temperature switch that reduces the temperature dependence of the permanent magnet even if it is a 4-type magnet.

That is, the present invention provides a permanent magnetic open circuit at the tip of a yoke integrally formed in a substantially U-shape made of a heat-sensitive magnetic material that rapidly loses its magnetism at a certain temperature. A magnet is arranged, and a reed switch is arranged so as to constitute a second magnetic circuit parallel to the first magnetic closed circuit through the bush piece, and has a large temperature dependence and a negative temperature coefficient. A temperature switch characterized in that a second magnetic material is arranged to form a third magnetic closed circuit in parallel with the first and second magnetic closed circuits, thereby reducing the influence of outside temperature. be.

The present invention will be further explained with reference to the drawings.

3 to 5 show embodiments of a temperature switch according to the present invention. In FIG. 3, the yoke is made of a temperature-sensitive magnetic material such as an Nj-Cr-Fe alloy and is integrally formed in a substantially U-shape, and has holes in the relative same position of the legs 2-1 and 2-2. 2, a cylindrical permanent magnet 1 made of a material such as a ferrite magnet magnetized in the direction of the spacing between the legs 2-1 and 2-2 is attached to the inner flange of the permanent magnet and a hole provided in the yoke 2. A glass-sealed door switch 4 is inserted to form a cross section of the whole.

Further, a magnetic material 9 having a large magnetic temperature coefficient and negative characteristics, such as a Ni--Fe alloy, is fixed so as to short-circuit the tips of the legs 2-1 and 2-2 of the yoke 2. In this way, the yoke 2, the reed switch contact piece 8, and the magnetic material 9 form parallel closed circuits as shown by the flow of magnetic fluxes ◇T, JR, and ◇M from the magnet 1, respectively, and the yoke The on/off operation of the switch is performed as described above at a point near the Curie temperature of 2. Furthermore, due to the incorporation of the magnetic material 9 having a negative temperature coefficient, if the temperature near the magnet 1 drops extremely, for example, the magnetic material 9
Since the magnetic resistance of becomes smaller and acts to increase the magnetic flux ■M passing through it, most of the magnetic flux increase △■ from the magnet 1 at that time is absorbed by the magnetic material 9, and as a result , the magnetic fluxes (T) and (R) flowing through the yoke 2 and the IJ switch 4 are hardly affected by the temperature drop, and therefore perform predetermined on/off operations based on the temperature of the yoke 2. Furthermore, when the outside temperature of the magnet 1 is high, the magnetic flux from the magnet 1 decreases, but at this time, the magnetic resistance of the magnetic material 9 increases and the magnetic flux ■w
Since it acts to reduce (or block)
Therefore, predetermined on/off operations are performed based on the temperature of the yoke 2. In this way, despite the temperature dependence of the permanent magnet 1, a temperature switch is obtained that reliably performs on/off operations almost unaffected by temperature.
Also, therefore, miniaturization becomes possible.

4 and 5 operate on exactly the same principle, and in FIG. 4 a cylindrical magnetic material 9 is placed on the outside of the magnet 1, and in FIG. A cylindrical magnetic material 9 is arranged to form a third magnetic closed circuit. In any case, the magnetic closed circuit formed by the magnetic material 9 and the permanent magnet 1 is treated as a bypass circuit,
It is necessary to take into account the magnetic properties of the yoke 2 and the magnetic properties of the lead piece of the lead switch 4 in determining its properties and cross-sectional area. FIG. 6 shows a more specific embodiment.

The principle is the same as the embodiment shown in FIG. A yoke 2 is formed by molding a Ni-Cr-Fe alloy with a Curie temperature of 260 qo into a substantially U-shape, and a hole is provided at the tip of the yoke 2.
After fixing the cylindrical mother ferrite magnet 1 to this hole with a yellow steel eyelet 10, insert the glass-sealed lead switch 4 into the eyelet 10, and connect the contact piece 8 and the lead wire 6 by soldering or the like. Then, a two-part case 11 made of aluminum or the like is attached via a cap 15 made of phenol resin or the like so as to press the magnetic material 9, and bosses and screws are inserted into the screw holes 16 and screw holes 13. This is a temperature switch. The present invention has been described above, and it is possible to control the temperature in an extremely wide range without being affected by ambient temperature, and because the device is compact and the yoke is constructed as one piece, there is no process such as welding. It can be said that the device is highly reliable, compact, and inexpensive.

[Brief explanation of the drawing]

FIG. 1a is a schematic front view of a conventional example, FIG. 1b is a diagram showing the characteristics of the same example, and FIG. 2 is a diagram showing the same example installed in a forced circulation oil heater. 3 shows an embodiment of the present invention, a is a left side view, b is a front sectional view, FIGS. 4 and 5 are front sectional views of other embodiments of the invention, and FIG. 6 is a front sectional view of the present invention. A more specific embodiment of the invention is shown, in which a is a front sectional view and b is a right side view.
1...Permanent magnet, 2...Temperature-sensitive magnetic material,
3, 9...Magnetic material, 4...Reed switch, 5...Resin, 6...Lead wire, 8...
IJ-doswitch piece, 10... Eyelet, 11
...Non-magnetic case, 12...Solder, 13, 14
...Screw hole, 15...Cap, 16...Screw hole, A...Forced circulation hot air heater high temperature section, 8.
...Forced circulation hot air heater control unit. Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1 A temperature-sensitive magnetic material that rapidly loses its magnetism at a certain temperature.
A permanent magnet, which together with the yoke forms a first magnetic closed circuit, is disposed at the tip of the yoke integrally constructed in the shape of a letter, and a reed switch is connected in parallel to the first magnetic circuit through its contact piece. arranged to constitute a second magnetic closed circuit,
In addition, a second magnetic material having a large temperature dependence and a negative coefficient is arranged to constitute a third magnetic closed circuit in parallel with the first and second magnetic closed circuits, thereby eliminating the influence of outside temperature. A temperature switch characterized by reduced temperature.