JPS6248338B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing an air blow detection device that combines a temperature switch composed of a temperature-sensitive magnetic material, a reed switch, and a permanent magnet, and a heater element.

This type of airflow detection device is mainly used for detecting abnormal stoppage of cooling fans of power supply equipment and the like. However, in the conventional heater element, an ordinary resistor is used, and when the fan stops abnormally, the temperature of the resistor heating element rises abnormally, which poses a problem in terms of safety.
Furthermore, since a reed switch is used, there is a problem in that the glass sealing part is easily damaged during assembly.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an object of the present invention is to provide an air blowing detection device that uses a positive temperature coefficient thermistor having a self-temperature holding function as a heater element and ensures thermal safety when a fan stops abnormally. do.

The present invention is also easy to assemble and has a low defect rate.
Therefore, an inexpensive air blow detection device is provided.

The present invention provides an air blow detection device comprising a temperature switch composed of a temperature-sensitive magnetic body, a reed switch, and a permanent magnet, a heater element that heats the temperature-sensitive magnetic body, and a rectangular insulating frame that holds these elements. In the device, a positive temperature coefficient thermistor having a self-temperature holding function is used as the heater element, and when the temperature switch is installed in the frame, the connection between the lead of the reed switch and the lead wire connection terminal is improved.

Examples of the present invention will be described below.

FIG. 1 is a front view of a blowing air detection device obtained according to the present invention, and FIG. 2 is an exploded perspective view thereof.

This device has two legs of a U-shaped temperature-sensitive magnetic body 4.
A temperature switch in which two permanent magnets 5 and 5' are fitted around the outer periphery of a reed switch 7 with magnetic poles aligned in the axial direction and with a spacer 6 made of a gap or a non-magnetic material, and a temperature switch with positive characteristics. A heater element consisting of a thermistor 3, a first electrode plate 1 to which a power source is connected, and a square-shaped second electrode plate 2, and a rectangular insulating main frame 9 for holding these elements.
It consists of an auxiliary frame body 10 made of the same material.

In the temperature switch, the open end of the temperature-sensitive magnetic body 4 is fitted into grooves 91 and 91' provided in the main frame body 9,
Leads 71, 71' of the reed switch 7 and lead wire connection terminals 8, 8' welded to the ends of the leads are fitted into grooves 92, 92' provided in the main frame 9 and held therein. One end of the electrode plate 1 is fitted into a groove 93' provided in the inner wall of the main frame 9, and the other end serves as a lead wire connection terminal 81 and is fitted into a groove 93 provided in the main frame 9. That is, this electrode plate 1
is installed so as to be in close contact with the outer surface of the closed end side of the temperature-sensitive magnetic body 4 of the temperature switch held in the main frame 9, and holds the temperature switch. Further, one end of the electrode plate 2 on the same side as the lead wire connection terminal 81 of the electrode plate 1 is fitted into a groove 94 provided in the inner wall of the main frame body 9, and the other end is used as the lead wire connection terminal 82 and is inserted into the main frame body 9. It is fitted into a groove 94' provided in the body 9.
The electrode plate 2 is installed on the main frame 9 with the positive temperature coefficient thermistor 3 sandwiched between its upper side and the electrode plate 1. The positive temperature coefficient thermistor 3 includes projecting pieces 21 and 2 formed by folding back and cutting up the electrode plate 2.
1' and the projecting pieces 22, 22' prevent displacement in the surface direction. An auxiliary frame 10 is fixed to the main frame 9 by adhesive or welding to prevent the temperature switch and heater element from falling off. Reference numerals 95 and 95' are mounting pieces for the main body of the apparatus.

This device is installed in a ventilation path using mounting pieces 95, 95' so that air can pass through the main frame 9,
A power source is connected to electrode plate 1 and electrode plate 2. As a result, the positive temperature coefficient thermistor 3 generates heat, but
When air is blown at the rated wind speed, heat is dissipated by the air flow, so the temperature of the closed end 41 of the temperature-sensitive magnetic body 4 is kept below its Kyrie point, and the entire temperature-sensitive magnetic body 4 exhibits ferromagnetism. ing. Therefore, most of the magnetic flux from the permanent magnets 5, 5' flows through the temperature-sensitive magnetic body 4, and only a small amount of magnetic flux flows through the contact portion of the reed switch 7, so that the reed switch 7 is in an open state.

When the wind speed becomes lower than the rated wind speed from this state, the temperature of the positive temperature coefficient thermistor 3 increases because heat dissipation due to the air flow decreases. Following this, the temperature of the electrode plate 1 and the closed end portion 41 of the temperature-sensitive magnetic body 4 also rises, and when the temperature of the closed end portion 41 reaches the Curie temperature Tc,
Becomes paramagnetic. Due to this, the permanent magnet 5,
Most of the magnetic flux from 5' flows into the leads of reed switch 7, causing the contacts to close, and an electric circuit connected to terminals 8 and 8' detects a decrease in air flow. On the other hand, since the positive temperature coefficient thermistor 3 is stably maintained at a predetermined constant temperature above the Curie temperature Tc by its self-temperature holding function, it Thermal safety during shutdown is significantly improved.

By the way, when assembling this device, in particular,
When setting the temperature switch on the main frame 9, it is necessary to be careful not to damage the reed switch 7. That is, it is important for mass production to minimize the stress applied to the glass sealing portions of the leads 71, 71' of the reed switch 7 during assembly to prevent glass breakage and the like.

Therefore, in the present invention, when setting the temperature switch, the leads 71, 71' of the reed switch 7 and the lead wire connection terminals 8, 8' are separately set in the grooves 92, 92' of the main frame 9, and After the body 10 is fixed, the protruding portions 72, 72' of the leads 71, 71' extending from the main frame body 9 to the outside and the lead wire connection terminals 8, 8' are connected by spot welding from the outside. . According to this method, the leads 71, 71 during assembly are more convenient than the conventional method in which the lead wire connection terminals and the leads of the reed switch are spot-welded in advance and assembled into the main frame 9 before each component is assembled. The stress applied to the reed switch is greatly reduced, and the defective rate due to damage to the reed switch can be greatly improved.

FIG. 3 is a diagram showing a method of performing spot welding using external welding electrodes 11 and 12.

The lower electrode 12 has a bent portion to avoid contact with the lead wire connection terminal 81, and the upper end surface is provided with a groove corresponding to the lead diameter of the reed switch 7 to prevent positional deviation during welding. I have to.

As described above, according to the present invention, it is possible to provide an inexpensive air blow detection device that has high thermal safety, is easy to assemble, and can greatly reduce breakage of reed switches to improve yield. .

[Brief explanation of the drawing]

FIG. 1 is a front view of a blowing air detection device obtained according to the present invention, FIG. 2 is an exploded perspective view of FIG. 1, and FIG. 3 is a diagram showing a spot welding method. In the figure, 1, 2: electrode plate, 3: positive temperature coefficient thermistor, 4: temperature-sensitive magnetic material, 5, 5': permanent magnet, 7:
Lead switch, 8, 8': Lead wire connection terminal,
9: Insulating main frame body, 10: Auxiliary frame body, 11, 1
2: Electrode for spot welding.

Claims (1)

[Claims] 1 Temperature control is achieved by installing two permanent magnets around the outer periphery of a reed switch, with their magnetic poles aligned in the axial direction and fitted at a constant distance from each other, between the legs of a roughly U-shaped temperature-sensitive magnetic body. In the air blowing detection device that includes a switch, a heater element that heats the temperature-sensitive magnetic material, and a rectangular insulating frame that holds these, the temperature switch is located at the ends of both legs of the temperature-sensitive magnetic material. is inserted into a groove provided in the inner wall of the frame, and the lead of the reed switch is led out of the frame through the groove provided in the frame, and the heater element includes a positive temperature coefficient thermistor between two electrode plates. These two electrode plates are mounted on the frame so that one of the electrode plates is in contact with the outer surface of the closed end side of the temperature-sensitive magnetic body, and the frame is further placed in such a way that it is in contact with the lead of the reed switch. A lead wire connecting terminal is inserted into the groove of the reed switch, and the lead wire connecting terminal is connected to the lead of the reed switch protruding outside the frame by spot welding from the outside after each component is assembled. A manufacturing method of a characteristic air blowing detection device.