JPH056536Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention relates to an air blow detection device for a cooling blower that prevents overheating in equipment using a temperature-sensitive switch made of a reed switch, a permanent magnet, and a temperature-sensitive magnetic material. It is something.

<Prior Art> Conventionally, when a blower that cools heat generated from an electronic device stops due to some abnormality, a blower detection device is used that detects the ambient temperature and closes or opens a switch. This kind of airflow detection device is
Generally, it is formed by arranging a reed switch between the ends of both legs of a U-shaped temperature-sensitive magnetic body having a desired Curie temperature, and a ring-shaped permanent magnet having the same polar direction around the outer periphery of the reed switch. Furthermore, a positive temperature coefficient thermistor is closely attached to the base of the U-shaped temperature-sensitive magnetic material,
By detecting the ambient temperature using this thermistor, the above-mentioned reed switch is closed or opened, and the power is cut off to prevent overheating inside the device.

<Problems that the invention aims to solve> However, in this type of conventional air blower detection device, the response time from when the blower stops until the reed switch closes or opens varies greatly depending on the ambient temperature. Therefore, there is a drawback that the range of change in response time cannot be narrowed. Another disadvantage is that it cannot be used if the temperature range exceeds a specified range.

<Means for solving the problem> The air blow detection device according to this invention has a U-shaped temperature-sensitive magnetic material whose magnetic properties change depending on the desired Curie temperature. A ring-shaped permanent magnet magnetized in each direction is fixed, a reed switch is inserted and fixed in the center of these magnets, and a positive temperature coefficient thermistor is closely attached to the base of the U-shaped temperature-sensitive magnetic body. Rotatable control permanent magnets are provided at opposing positions above the tips of both legs of the temperature-sensitive magnetic body.

<Function> A control magnet magnetized above the tip of the temperature-sensitive magnetic material is installed parallel to the reed switch, and by making this control magnet rotatable, the magnetic field at the contact point of the reed switch is adjusted to maintain an appropriate ambient temperature. A desired operating point can be selected from the relationship between the range and response time.

<Example> A first example of the present invention will be described with reference to FIG. 1 showing the configuration of a closed molded air blow detection device.

The closed-molded air detection device shown in FIG. 1 has a U-shaped temperature-sensitive magnetic body 1 whose magnetic properties change at a desired Curie temperature, and the holes at the tips of its legs 11, 11' are , a reed switch 4 is installed through the contact point of the reed switch 4. In addition, these legs 11 and 1
A pair of ring-shaped permanent magnets 2 and 2', each magnetized in the same direction, are fixed to the outer periphery of the reed switch 4 with a gap 3 between them and the magnet 1'. The reed switch 4 is held by the legs of the insulating holding frame 8 via lead wires at both ends.

Further, a heat sensitive body, such as a positive temperature coefficient thermistor 5, whose main surfaces are sandwiched between an electrode plate 6 and an elastic electrode body 7, is closely attached to the base 12 of the temperature sensitive magnetic body 1. Furthermore, a control permanent magnet 13 is provided at the tip of the temperature-sensitive magnetic body 1 on its upper surface with an insulating holding frame 8 in between so as to be horizontally rotatable with a knob 14 .

Now, when the heat transmitted to the base 12 of the temperature-sensitive magnetic body 1 by the positive temperature coefficient thermistor 5 is less than the Curie temperature at the time of air blowing, the temperature-sensitive magnetic body 1 is a ferromagnetic body,
The magnetic flux from the inner magnetic poles of permanent magnets 2 and 2' is
Since the area is narrow, the contact point of the reed switch 4 cannot be operated. Further, since the magnetic flux from the outer magnetic poles of the permanent magnets 2, 2' passes through the temperature-sensitive magnetic body 1, the contacts of the reed switch 4 are in an open state. Here, when the temperature of the positive temperature coefficient thermistor 5 rises in a calm state,
Depending on the temperature, the temperature-sensitive magnetic material 1 becomes a paramagnetic material, and no magnetic flux passes through it. By this,
The magnetic flux from the outer magnetic poles of the permanent magnets 2, 2' passes through the contacts of the reed switch 4, and the reed switch 4 is brought into a closed state.

In addition, if the operating temperature of the temperature-sensitive switch is high and the response time is longer than the specified value, if the control permanent magnet 13 is oriented in the same direction as the permanent magnets 2 and 2' as shown in FIG. The magnetic flux is biased in the direction of , lowering the operating temperature of the temperature-sensitive switch and providing proper response time. On the other hand, if the response time is too fast, the knob 14 of the control permanent magnet 13 may be rotated to control the response time to an appropriate value.

FIG. 3 shows an example of a releasable air blowing detection device as a second embodiment. According to this configuration,
The reed switch 4 is inserted into the hole provided at the tip of the leg portions 11, 11' of the U-shaped temperature-sensitive magnetic body 1 having a desired Curie temperature, and the reed switch 4 is
Ring-shaped permanent magnets 2, 2' having the same magnetization direction are fixed on the outer periphery of the legs 11, 11'.
The reed switch 4 is held by the legs of an insulating holding frame 8. At the top of this holding frame 8 is a reed switch 4.
A control permanent magnet 13 is provided which is magnetized in parallel to the magnet, and the magnet is horizontally rotated by an adjustment knob 14.

According to this structure, when the response time is larger than a specified value, the direction of the magnetic pole of the control permanent magnet 13 is rotated in the opposite direction to that of the permanent magnets 2 and 2' as shown in FIG. Biasing in the direction of magnetic flux 16 lowers the temperature sensitive switch's operating point to provide proper response time.

If the response time is too short, the control permanent magnet 13 may be rotated using the knob 14 so as to be in the opposite direction to that shown in FIG.

<Effects of the invention> As described above, according to the invention, the response time can be reduced by rotating the direction of the magnetic pole of the control permanent magnet 13 for either closed molding or open molding. It can be adjusted with high precision, and thereby the equipment used can be quickly prevented from overheating that would occur in the event of a blower failure, which has a significant effect on improving reliability.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the configuration of a first embodiment according to the present invention, FIG. 2 is an explanatory diagram showing the operation of FIG. 1, and FIG. 3 is a diagram showing the configuration of a second embodiment according to the present invention. The front view and FIG. 4 are explanatory diagrams showing the operation of FIG. 3. In addition, in the figure, 1... Temperature-sensitive magnetic material, 2, 2'... Permanent magnet, 3
... Gap, 4 ... Reed switch, 5 ... Positive temperature coefficient thermistor, 6 ... Electrode plate, 7 ... Elastic electrode plate, 8 ... Insulation holding frame, 11, 11' ... Legs,
12...Base, 13...Control permanent magnet, 14...
…Knob.

Claims (1)

[Scope of utility model registration request] Ring-shaped permanent magnets magnetized in the same direction are fixed on the outer periphery of the holes in the tips of both legs of a temperature-sensitive magnetic material whose magnetic properties change depending on the desired Curie temperature. A reed switch is inserted and fixed in the center, a positive temperature coefficient thermistor is closely attached to the base of the temperature-sensitive magnetic body, and rotatable control permanent magnets are placed at opposing positions at the upper ends of both legs of the temperature-sensitive magnetic body. Air blow detection device.